Alkynes: Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Rhodium: Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)Click Chemistry: Organic chemistry methodology that mimics the modular nature of various biosynthetic processes. It uses highly reliable and selective reactions designed to "click" i.e., rapidly join small modular units together in high yield, without offensive byproducts. In combination with COMBINATORIAL CHEMISTRY TECHNIQUES, it is used for the synthesis of new compounds and combinatorial libraries.Alkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Propanols: Isomeric forms and derivatives of PROPANOL (C3H7OH).Azides: Organic or inorganic compounds that contain the -N3 group.Palladium: A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.Cycloparaffins: Alicyclic hydrocarbons in which three or more of the carbon atoms in each molecule are united in a ring structure and each of the ring carbon atoms is joined to two hydrogen atoms or alkyl groups. The simplest members are cyclopropane (C3H6), cyclobutane (C4H8), cyclohexane (C6H12), and derivatives of these such as methylcyclohexane (C6H11CH3). (From Sax, et al., Hawley's Condensed Chemical Dictionary, 11th ed)Alkadienes: Acyclic branched or unbranched hydrocarbons having two carbon-carbon double bonds.Ruthenium: A hard, brittle, grayish-white rare earth metal with an atomic symbol Ru, atomic number 44, and atomic weight 101.07. It is used as a catalyst and hardener for PLATINUM and PALLADIUM.Cycloaddition Reaction: Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products.Amination: The creation of an amine. It can be produced by the addition of an amino group to an organic compound or reduction of a nitro group.IminesIndolizidines: Saturated indolizines that are fused six and five-membered rings with a nitrogen atom at the ring fusion. They are biosynthesized in PLANTS by cyclization of a LYSINE coupled to ACETYL COENZYME A. Many of them are naturally occurring ALKALOIDS.Vinyl CompoundsOrganometallic Compounds: A class of compounds of the type R-M, where a C atom is joined directly to any other element except H, C, N, O, F, Cl, Br, I, or At. (Grant & Hackh's Chemical Dictionary, 5th ed)Silanes: Compounds similar to hydrocarbons in which a tetravalent silicon atom replaces the carbon atom. They are very reactive, ignite in air, and form useful derivatives.Organogold Compounds: Organic compounds that contain GOLD as an integral part of the molecule. Some are used as ANTIRHEUMATIC AGENTS. The term chrysotherapy derives from an ancient Greek term for gold.Organosilicon Compounds: Organic compounds that contain silicon as an integral part of the molecule.Hempa: A chemosterilant agent that is anticipated to be a carcinogen.Isocyanates: Organic compounds that contain the -NCO radical.Diynes: Compounds with two triple bonds. Some of them are CYTOTOXINS.Combinatorial Chemistry Techniques: A technology, in which sets of reactions for solution or solid-phase synthesis, is used to create molecular libraries for analysis of compounds on a large scale.KetonesHeterocyclic Compounds: Ring compounds having atoms other than carbon in their nuclei. (Grant & Hackh's Chemical Dictionary, 5th ed)Copper: A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Chemistry, Organic: The study of the structure, preparation, properties, and reactions of carbon compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)AcetyleneTerminology as Topic: The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.Polyenes: Hydrocarbons with more than one double bond. They are a reduced form of POLYYNES.PhotochemistrySodium Hydroxide: A highly caustic substance that is used to neutralize acids and make sodium salts. (From Merck Index, 11th ed)Transition Temperature: The temperature at which a substance changes from one state or conformation of matter to another.Ammonia: A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.Methylene Blue: A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Electrons: Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.Diagnosis, Oral: Examination of the mouth and teeth toward the identification and diagnosis of intraoral disease or manifestation of non-oral conditions.Periodontics: A dental specialty concerned with the histology, physiology, and pathology of the tissues that support, attach, and surround the teeth, and of the treatment and prevention of disease affecting these tissues.Halogens: A family of nonmetallic, generally electronegative, elements that form group 17 (formerly group VIIa) of the periodic table.Hydrocarbons, HalogenatedAlkanes: The generic name for the group of aliphatic hydrocarbons Cn-H2n+2. They are denoted by the suffix -ane. (Grant & Hackh's Chemical Dictionary, 5th ed)Alkane 1-Monooxygenase: A P450 oxidoreductase that catalyzes the hydroxylation of the terminal carbon of linear hydrocarbons such as octane and FATTY ACIDS in the omega position. The enzyme may also play a role in the oxidation of a variety of structurally unrelated compounds such as XENOBIOTICS, and STEROIDS.Isoquinolines: A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)Sulfur Oxides: Inorganic oxides of sulfur.Thalictrum: A plant genus of the family RANUNCULACEAE. Members contain isoquinoline alkaloids and triterpene glycosides.

Smoothing of the thermal stability of DNA duplexes by using modified nucleosides and chaotropic agents. (1/688)

The effect of alkyltrimethylammonium ions on the thermostability of natural and modified DNA duplexes has been investigated. We have shown that the use of tetramethylammonium ions TMA+along with the chemical modification of duplexes allow the fine adjustment of T m and the possibility of obtaining several duplex systems with varied isostabilizedtemperatures, some of which show greater stability than those of natural DNA. This approach could be very useful for DNA sequencing by hybridization.  (+info)

Inhibition of glutathione synthesis with propargylglycine enhances N-acetylmethionine protection and methylation in bromobenzene-treated Syrian hamsters. (2/688)

The finding that liver necrosis caused by the environmental glutathione (GSH)-depleting chemical, bromobenzene (BB) is associated with marked impairment in O- and S-methylation of BB metabolites in Syrian hamsters raises questions concerning the role of methyl deficiency in BB toxicity. N-Acetylmethionine (NAM) has proven to be an effective antidote against BB toxicity when given after liver GSH has been depleted extensively. The mechanism of protection by NAM may occur via a replacement of methyl donor and/or via an increase of GSH synthesis. If replacement of the methyl donor is an important process, then blocking the resynthesis of GSH in the methyl-repleted hamsters should not decrease NAM protection. This hypothesis was examined in this study. Propargylglycine (PPG), an irreversible inhibitor of cystathionase, was used to inhibit the utilization of NAM for GSH resynthesis. Two groups of hamsters were pretreated with an intraperitoneal (ip) dose of PPG (30 mg/kg) or saline 24 h before BB administration (800 mg/kg, ip). At 5 h after BB treatment, an ip dose of NAM (1200 mg/kg) was given. Light microscopic examinations of liver sections obtained 24 h after BB treatment indicated that NAM provided better protection (P < 0.05) in the PPG + BB + NAM group than in the BB + NAM group. Liver GSH content, however, was lower in the PPG + BB + NAM group than in the BB + NAM group. The Syrian hamster has a limited capability to N-deacetylated NAM. The substitution of NAM with methionine (Met; 450 mg/kg) resulted in a higher level of GSH in the BB + Met group than in the BB + NAM group (P < 0.05). The enhanced protection by PPG in the PPG + BB + NAM group was accompanied by higher (P < 0.05) urinary excretions of specificO- and S-methylated bromothiocatechols than in the BB + NAM group. The results suggest that NAM protection occurs primarily via a replacement of the methyl donor and that methyl deficiency occurring in response to GSH repletion plays a potential role in BB toxicity.  (+info)

Inhibition of gene expression by anti-sense C-5 propyne oligonucleotides detected by a reporter enzyme. (3/688)

Using a reporter plasmid containing the luciferase gene under the control of the insulin-like growth factor 1 (IGF-1) promoter region [including its 5' untranslated region (UTR)], we demonstrate that a 17-mer oligophosphorothioate containing C-5 propyne pyrimidines is able to inhibit luciferase gene expression in the nanomolar concentration range when the anti-sense oligonucleotide is targeted either to a coding sequence in the luciferase gene or to the 5' UTR of the gene for IGF-1. Inhibition was obtained independently of whether the plasmid and the anti-sense oligonucleotide were co-transfected or transfected separately into hepatocarcinoma cells. However, the efficiency of inhibition by the anti-sense oligonucleotides was 10-fold greater in the first case. The unmodified oligophosphorothioate targeted to the 5' UTR of IGF-1 did not inhibit luciferase gene expression at a 100-fold higher concentration unless its length was increased from 17 to 21 nt, in which case an inhibition of gene expression was obtained and an IC50 of 200 nM was observed.  (+info)

Elevated expression of liver gamma-cystathionase is required for the maintenance of lactation in rats. (4/688)

Liver gamma-cystathionase activity increases in rats during lactation; its inhibition due to propargylglycine is followed by a significant decrease in lactation. This is reversible by N-acetylcysteine administration. To study the role of liver gamma-cystathionase and the intertissue flux of glutathione during lactation, we used lactating and virgin rats fed liquid diets. Virgin rats were divided into two groups as follows: one group was fed daily a diet containing the same amount of protein that was consumed the previous day by lactating rats (high protein diet-fed rats); the other virgin group was fed the normal liquid diet (control). The expression and activity of liver gamma-cystathionase were significantly greater in lactating rats and in high protein diet-fed virgin rats compared with control rats. The total glutathione [reduced glutathione (GSH) + oxidized glutathione (GSSG)] released per gram of liver did not differ in lactating rats or in high protein diet-fed rats, but it was significantly higher in these two groups than in control virgin rats. Liver size and the GSH + GSSG released by total liver were significantly higher in lactating rats than in high protein diet-fed virgin rats, and this difference was similar to the amount of glutathione taken up by the mammary gland (454.2 +/- 36.0 nmol/min). The uptake of total glutathione by the lactating mammary gland was much higher than the uptakes of free L-cysteine and L-cystine, which were negligible. These data suggest that the intertissue flux of glutathione is an important mechanism of L-cysteine delivery to the lactating mammary gland, which lacks gamma-cystathionase activity. This emphasizes the physiologic importance of the increased expression and activity of liver gamma-cystathionase during lactation.  (+info)

Guest exchange in an encapsulation complex: a supramolecular substitution reaction. (5/688)

Encapsulation complexes are reversibly formed assemblies in which small molecule guests are completely surrounded by large molecule hosts. The assemblies are held together by weak intermolecular forces and are dynamic: they form and dissipate on time scales ranging from milliseconds to days-long enough for many interactions, even reactions, to take place within them. Little information is available on the exchange process, how guests get in and out of these complexes. Here we report that these events can be slow enough for conventional kinetic studies, and reactive intermediates can be detected. Guest exchange has much in common with familiar chemical substitution reactions, but differs in some respects: no covalent bonds are made or broken, the substrate is an assembly rather than a single molecule, and at least four molecules are involved in multiple rate-determining steps.  (+info)

Effects of a lipoxygenase inhibitor, panaxynol, on vascular contraction induced by angiotensin II. (6/688)

We investigated whether a lipoxygenase inhibitor, panaxynol, affected the vascular contraction induced by angiotensin (Ang) II and the mean arterial pressure in spontaneously hypertensive rats (SHR). Panaxynol suppressed dose-dependently the contractile responses induced by 30 nM Ang II in isolated intact and endothelial cell-denuded aorta in the hamster. IC50 values in the intact and endothelial cell-denuded aorta were 23 and 20 microM, respectively. In SHR, the mean arterial pressure after injection of 30 and 60 mg/kg panaxynol was reduced, and the maximum hypotensive values were 23 and 48 mmHg, respectively. Thus, lipoxygenase products may affect the renin-angiotensin system.  (+info)

Similarity and dissimilarity in mode and mechanism of action between YT-146, a selective adenosine receptor A2 agonist, and adenosine in isolated canine hearts. (7/688)

To elucidate the differences in mode and mechanism of action between YT-146, a highly selective adenosine A2 receptor agonist, and adenosine, we compared their effects on coronary circulation and myocardium and modifications of these effects by glibenclamide, a blocker of ATP-sensitive potassium (K) channels, in three kinds of isolated, blood-perfused canine heart preparations. YT-146 and adenosine were injected i.a. In all preparations both YT-146 and adenosine increased coronary blood flow and in this respect YT-146 was about 5 times as potent as adenosine. The increase in blood flow caused by adenosine was transient, whereas that produced by YT-146 was biphasic; the transient increase was followed by a sustained one. In isolated, blood-perfused sinoatrial (SA) node preparations, YT-146 failed to affect sinus rate, whereas adenosine reduced sinus rate by about 38% at its maximum effect. In isolated, blood-perfused atrioventricular (AV) node preparations, when injected into the artery supplying the AV node, YT-146 exerted no effect on AV conduction time, whereas adenosine prolonged AV conduction time by about 17% at the maximum effect. In isolated, blood-perfused papillary muscle preparations, the force of contraction was affected by neither YT-146 nor adenosine. In the same preparations the effect of YT-146 in increasing coronary blood flow was antagonized by glibenclamide in such a manner that the maximum increase was suppressed, but that of adenosine was not. Reactive hyperemia induced by ischemia for 30 seconds was not affected by glibenclamide. These results suggest that although both YT-146 and adenosine produce an increase in coronary blood flow via adenosine A2 receptors, the opening of ATP- or glibenclamide-sensitive K channels is involved in the action of the former, but scarcely in the action of the latter. The opening of ATP- or glibenclamide-sensitive K-channels is less likely involved in reactive hyperemia.  (+info)

NAD(+)-dependent (S)-specific secondary alcohol dehydrogenase involved in stereoinversion of 3-pentyn-2-ol catalyzed by Nocardia fusca AKU 2123. (8/688)

An NAD(+)-dependent alcohol dehydrogenase was purified to homogeneity from Nocardia fusca AKU 2123. The enzyme catalyzed (S)-specific oxidation of 3-pentyn-2-ol (PYOH), i.e., part of the stereoinversion reaction for the production of (R)-PYOH, which is a valuable chiral building block for pharmaceuticals, from the racemate. The enzyme used a broad variety of secondary alcohols including alkyl alcohols, alkenyl alcohols, acetylenic alcohols, and aromatic alcohols as substrates. The oxidation was (S)-isomer specific in every case. The K(m) and Vmax for (S)-PYOH and (S)-2-hexanol oxidation were 1.6 mM and 53 mumol/min/mg, and 0.33 mM and 130 mumol/min/mg, respectively. The enzyme also catalyzed stereoselective reduction of carbonyl compounds. (S)-2-Hexanol and ethyl (R)-4-chloro-3-hydroxybutanoate in high optical purity were produced from 2-hexanone and ethyl 4-chloro-3-oxobutanoate by the purified enzyme, respectively. The K(m) and Vmax for 2-hexanone reduction were 2.5 mM and 260 mumol/min/mg. The enzyme has a relative molecular mass of 150,000 and consists of four identical subunits. The NH2-terminal amino acid sequence of the enzyme shows similarity with those of the carbonyl reductase from Rhodococcus erythropolis and phenylacetaldehyde reductase from Corynebacterium sp.  (+info)

Youre right; the definition in your book is simplistic. A terminal alkyne would be better defined as "an alkyne with the formula $\ce{RC_2H}$", differentiating from an internal alkyne, which would have the formula $\ce{RC_2R}$ and the added stipulation that neither R nor R can be a hydrogen. Equivalently stated as in Wikipedia, an internal alkyne has carbon substitutents on all acetylenic carbons, and a terminal alkyne is therefore not an internal alkyne because at least one acetylenic carbon has a hydrogen bonded to it.. The example formula you cite is vinylacetylene, systematic name butenyne or 1-buten-3-yne (heres your IUPAC nomenclature rules favoring double bonds at work; otherwise itd be ethynylbutene or similar). It is indeed an example of a terminal alkyne, having the exploded formula (C2H3)C2H.. ...
Evaluation of biofilm formation on novel copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based resins for dental restoratives Journal Article ...
Rh(III)-catalyzed C−H bond annulation with alkynes has excogitated into a potent method for the preparation of highly substituted polycyclic aromatic and heteroaromatic compounds. Here Rh(III)-catalyzed annulation of 4-phenyl quinazolines with internal alkynes via dual C−H bond activation has been explored. The synthetic procedure has the advantages of high efficiency and functional group tolerance, excellent regioselectivity and broad substrate scope under mild conditions and some of the resulting products exhibit intense fluorescence in the solution state. Such structural motifs may important precursors for further transformations into biologically active compounds & π-conjugated functional materials such as organic semiconductors and luminescent materials which have broad prospect in future life.. ...
Transition-metal-mediated cross coupling reaction of alkynes and alkenes has recently gained increasing significance in organic chemistry because it represents an efficient method for the formation of new carbon-carbon bond. In recent years, two types of the coupling reactions have been developed: intramolecular couplings of enynes and intermolecular couplings of alkynes and alkenes. These results were classified into two mechanistic pathways, one not involving carbon-carbon bond cleavage, insertion mechanism, and the other involving carbon-carbon bond cleavage, metathesis mechanism. While the coupling reactions of alkynes with substituted alkenes have been well developed, there are very few reports on the coupling of alkynes with the simplest alkene, ethylene documented in the literature. Our research goal is to develop a new rutheniumbased system to study the coupling reactions of alkynes with ethylene, and extend its scope to enyne and substituted alkenes.
Wang, Y.-F., Toh, K. K., Lee, J.-Y. and Chiba, S. (2011), Synthesis of Isoquinolines from α-Aryl Vinyl Azides and Internal Alkynes by Rh-Cu Bimetallic Cooperation. Angew. Chem., 123: 6049-6053. doi: 10.1002/ange.201101009 ...
Synonyms for alkyne in Free Thesaurus. Antonyms for alkyne. 2 synonyms for alkyne: acetylene, ethyne. What are synonyms for alkyne?
Communications DOI: 10.1002/anie.201100252 Asymmetric Catalysis C1-Symmetric Rh/Phebox-Catalyzed Asymmetric Alkynylation of a-Ketoesters** Takashi Ohshima,* Takahito Kawabata, Yosuke Takeuchi, Takahiro Kakinuma, Takanori Iwasaki, Takayuki Yonezawa, Hajime Murakami, Hisao Nishiyama, and Kazushi Mashima* Catalytic asymmetric alkynylation of carbonyl compounds is one of the most efficient routes for the synthesis of optically active propargylic alcohols, which are useful and versatile building blocks for a variety of functionalized molecules, such as biologically active natural products.[1] In the initial stages of development of this transformation, stoichiometric amounts of metal reagents such as organolithium, organomagnesium, and diorganozinc compounds were used to increase the nucleophilicity of the alkyne and to prevent an undesired retro reaction.[1, 2] In terms of atom economy,[3] however, the direct in situ generation of a metal alkynylide species from terminal alkynes using a catalytic ...
A regioselective hydroboration of alkynes has been developed by using commercially available zinc triflate as a catalyst, in the presence of catalytic amount of NaBHEt3. The reaction tolerates a wide range of terminal alkynes having several synthetically useful functional groups and proceeds regioselectively to furnish hydroborated products in moderate to excellent yields. This system shows moderate chemoselectivity towards terminal C equivalent to C bond over terminal and internal C=C bond and internal C equivalent to C bond.. ...
In this work, we confirmed that the copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction is an effective method for the organic-functionalization of polyoxometalates (POMs). Herein, for the first time, four novel 1,2,3-triazole functionalized polyoxovanadate (POV) organic-inorganic hybrids, (Bu4N)2[V6O13{(O
TY - GEN. T1 - A new sinthetic application of (dichloroiodo)benzene in reactions with alkenes and alkynes. AU - Yusubova, R. J.. AU - Filimonov, V. D.. AU - Yusubov, M. S.. AU - Chi, Ki Whan. PY - 2004. Y1 - 2004. N2 - A convenient synthesis of vicinal methoxychlorides, methoxyiodides from alkenes and alkynes using PhICl2/CH3OH, I 2/PhICl2/CH3OH is described.. AB - A convenient synthesis of vicinal methoxychlorides, methoxyiodides from alkenes and alkynes using PhICl2/CH3OH, I 2/PhICl2/CH3OH is described.. KW - (dichloroiodo)Benzene. KW - Alkenes. KW - Alkynes. KW - Chloromethoxylation. KW - Iodomethoxylation. UR - http://www.scopus.com/inward/record.url?scp=29144459782&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=29144459782&partnerID=8YFLogxK. M3 - Conference contribution. AN - SCOPUS:29144459782. SN - 0780383834. SN - 9780780383838. VL - 2. SP - 97. EP - 98. BT - 8th Korea-Russia International Symposium on Science and Technology - Proceedings: KORUS 2004. ER - ...
TY - JOUR. T1 - New oxidative transformations of alkenes and alkynes under the action of diacetoxyiodobenzene. AU - Yusubov, M. S.. AU - Zholobova, G. A.. AU - Filimonova, I. L.. AU - Chi, Ki Whan. PY - 2004/8/1. Y1 - 2004/8/1. N2 - Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.. AB - Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.. KW - Alkenes. KW - Alkynes. KW - Diacetoxyiodobenzene. KW - Oxidative rearrangement. KW - Polyvalent iodine compounds. UR - http://www.scopus.com/inward/record.url?scp=14944340734&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=14944340734&partnerID=8YFLogxK. U2 - 10.1007/s11172-005-0027-8. DO - ...
Best Chemical Properties Of The Alkynes Online Homework Help, Assignment Help providers on internet. 24 X 7 live online tutoring at Assignmenthelp.net.
Highly enantioselective allylic alkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminal alkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this transformation. Cold-spray ionization mass spectrometry (CSI-MS) and X-ray crystallography were used to identify some catalytic intermediates, which include guanidinium cuprate ion pairs and a copper-alkynide complex. A linear correlation between the enantiopurity of the catalyst and reaction product indicates the presence of a copper complex bearing a single guanidine ligand at the enantio-determining step. Further experimental and computational studies supported that the alkynylation of allylic bromide underwent an anti-SN2 pathway catalyzed by nucleophilic cuprate species. Moreover, ...
TY - JOUR. T1 - Bismuth(III)-Catalyzed hydration of terminal alkynes. T2 - Sustainable synthesis of methyl ketones in batch and flow. AU - Ötvös, Sándor B.. AU - Szécsényi, Zsanett. AU - Fülöp, F.. PY - 2019/8/5. Y1 - 2019/8/5. N2 - Environmentally benign synthesis of methyl ketones is demonstrated via unprecedented bismuth(III)-catalyzed activation and Markovnikov-type hydration of terminal acetylenes. Besides a batch process operating under reasonably mild conditions, a chemically intensified high-temperature continuous-flow methodology has also been developed using a coil reactor. The preparative capabilities of the flow process were demonstrated with multigram-scale alkyne hydrations. The methods presented rely on readily available bismuth(III) salts as "green" catalysts and exhibit less environmental concerns than earlier methods.. AB - Environmentally benign synthesis of methyl ketones is demonstrated via unprecedented bismuth(III)-catalyzed activation and Markovnikov-type hydration ...
Acetylene is the ultimate carbon building block (on paper, anyway!). It bears two relatively acidic C-H bonds (pKa 25) and can therefore be "alkylated" (i.e. deprotonated to give its conjugate base, then treated with an alkyl halide) on either end giving either a mono-substituted (also known as a "terminal" alkyne) or di-substituted ("internal") alkyne as desired. This is important because in first semester organic chemistry, this reaction represents an important means of extending the carbon chain. You dont learn that many reactions that form C-C. This reaction comes up a lot ...
Outline1. Bonding in alkynes. sp-Hybridization2. Physical properties and nomenclature of alkynes 3. Preparation and use of alkynes4. Addition to triple bonds. Hydrohalogenation5. Addition to triple bonds. Hydration6. Addition to triple bonds. Hydroboration-oxidation7. Addition to triple bonds....
Alkynes Hydrocarbons that contain carbon-carbon triple bonds C≡C Acetylene, the simplest alkyne is produced industrially from methane and steam at high temperature Our study of alkynes provides an introduction to organic synthesis, the preparation of organic molecules from simpler organic molecules
TY - JOUR. T1 - Hydrofluoroarylation of alkynes with fluoroarenes. AU - Kanyiva, Stephen Kyalo. AU - Kashihara, Natsuko. AU - Nakao, Yoshiaki. AU - Hiyama, Tamejiro. AU - Ohashi, Masato. AU - Ogoshi, Sensuke. PY - 2010/11/21. Y1 - 2010/11/21. N2 - A combination of Ni(cod)2 and PCyp3 is found to be an effective catalyst for chemoselective activation of the C-H bond of fluoroarenes over C-F bonds followed by insertion of alkynes to allow direct alkenylation of the electron-deficient arenes. The characteristics of the reactions are: a C-H bond ortho to a fluorine substituent is selectively activated; the reactivity of fluorobenzenes is roughly proportional to the number of fluorine atoms. The reaction conditions tolerate a broad range of both alkynes and fluoroarenes containing both electron-withdrawing and -donating groups, thus allowing efficient synthesis of a variety of substituted ethenes containing a fluoroaryl motif in high regio- and stereoselective manners. Mechanistic studies including ...
Alkyne functionalized Single layer graphene Flake size: 0.5-5 microns. Thickness: Single atomic layer >80% Purity: Carbon contents over 80% Alkyne functionalized online from Mknano.com.
Alkynes and Their Reactions Naming Alkynes Alkynes are named in the same general way that alkenes are named. In the IUPAC system, change the ane ending of the parent alkane name to the suffix yne. Choose
ALKYnes sem 1: 2011/2012. Khadijah Hanim bt Abdul Rahman School of Bioprocess Engineering, UniMAP Week 5: 13/10/2011 [email protected] Learning outcomes. Structure, nomenclature and naming alkynes DEFINE and ILLUSTRATE the principle in naming alkynes on few examples...
A Lewis acid-catalyzed insertion of unsymmetrical alkynes into electron-deficient alkenes was developed for the first time, and used to produce 34 hitherto unreported pentacyclic benzo[5,6]chromeno[2,3-b]indoles with generally good yields and complete stereoselectivity. A Yb(OTf)3-catalyzed reaction between
Preparation, properties and reactions of alkenes and alkynes: Physical properties of alkenes and alkynes (boiling points, density and dipole moments); Acidity of alkynes; Acid catalysed hydration of alkenes and alkynes (excluding the stereochemistry of addition and elimination); Reactions of alkenes with KMnO4 and ozone; Reduction of alkenes and alkynes; Preparation of alkenes and alkynes by elimination reactions; Electrophilic addition reactions of alkenes with X2, HX, HOX and H2O (X=halogen); Addition reactions of alkynes; Metal acetylides ...
Rhodium-Catalyzed Intermolecular Alkyne Cyclotrimerization Route to a Functionalized CycloparaphenyleneRhodium-Catalyzed Intermolecular Alkyne Cyclotrimerization Route to a Functionalized Cycloparaphenylene ...
A metal-free oxidative trifluoromethyl-thiolation of terminal alkynes using readily available CF3SiMe3 and elemental sulfur at room temperature has been developed. This reaction provides an efficient and convenient method for the preparation of alkynyl trifluoromethyl sulfides bearing a wide range of functional groups. Preliminary investigation revealed that elemental sulfur instead of air acted as the oxidant ...
TY - JOUR. T1 - Catalytic Enantioselective Addition of Terminal Alkynes to Aldehydes: Preparation of (S)-(-)-1,3-Diphenyl-2-Propyn-1-ol and (S)-(-)-4-Methyl-1-Phenyl-2-Pentyn-1,4-Diol. AU - Takita, Ryo. AU - Harada, Shinji. AU - Ohshima, Takashi. AU - Matsunaga, Shigeki. AU - Shibasaki, Masakatsu. PY - 2008. Y1 - 2008. U2 - 10.1002/0471264229.os085.13. DO - 10.1002/0471264229.os085.13. M3 - Article. VL - 85. JO - Organic Syntheses. JF - Organic Syntheses. SN - 0078-6209. ER - ...
Ligand lability offers a unique opportunity for access to metal-ligand cooperativity (MLC), helping to direct new organometallic and catalytic reactions. In recent years, ligand-assisted C-H bond activation and, more generally, proton migration have been of particular interest. This paper describes a detailed computational study into the mechanism, as well as the region and stereoselectivity, observed in a recently reported transformation where MLC in a 16-electron iridium(III) phosphoramidate complex plays a critical role in directing the activation of terminal alkynes toward the generation of novel five-membered (E)-vinyloxyirida(III)cycles. Five possible pathways for the formation of such products were investigated. Based on our findings, it is proposed that the reaction proceeds via a ligand-assisted proton shuttle (LAPS) mechanism, where the phosphoramidate phosphoryl (P=O) group assists in both alkyne C-H bond activation and C-H bond formation to form a vinylidene intermediate. Next, C-O ...
Poly(ethylene glycol) (PEG) is one of the most extensively studied antifouling coatings due to its ability to reduce protein adsorption and improve biocompatibility. Although the use of PEG for antifouling coatings is well established, the stability and density of PEG layers are often inadequate to provide optimum antifouling properties. To improve on these shortcomings, we employed the stepwise construction of PEG layers onto a silicon surface. Acetylene-terminated alkyl monolayers were attached to nonoxidized crystalline silicon surfaces via a one-step hydrosilylation procedure with 1,8-nonadiyne. The acetylene-terminated surfaces were functionalized via a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of the surface-bound alkynes with an azide to produce an amine terminated layer. The amine terminated layer was then further conjugated with PEG to produce an antifouling surface. The antifouling surface properties were investigated by testing adsorption of human serum albumin ...
In systematic chemical nomenclature, alkynes are named with the Greek prefix system without any additional letters. Examples include ethyne or octyne. In parent chains with four or more carbons, it is necessary to say where the triple bond is located. For octyne, one can either write 3-octyne or oct-3-yne when the bond starts at the third carbon. The lowest number possible is given to the triple bond. When no superior functional groups are present, the parent chain must include the triple bond even if it is not the longest possible carbon chain in the molecule. Ethyne is commonly called by its trivial name acetylene.. In chemistry, the suffix -yne is used to denote the presence of a triple bond. In organic chemistry, the suffix often follows IUPAC nomenclature. However, inorganic compounds featuring unsaturation in the form of triple bonds may be denoted by substitutive nomenclature with the same methods used with alkynes (i.e. the name of the corresponding saturated compound is modified by ...
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Jie Zhou,Jingjing Shi,Qi ZS,et al. Mild and Efficient Ir(III)-Catalyzed Direct C−H Alkynylation of N‑Phenoxyacetamides with Terminal Alkyne[J]. ACS Catalysis,2016,6(0):6999 ...
Various non-fluorescent alkynes for copper-catalyzed Click Chemistry. Fluorescent dye alkynes are listed under Reactive dyes category.
As you should know already, carbon is generally found in a tetravalent state - it forms four covalent bonds with other atoms. As you know from the section on alkenes, all four bonds are not necessarily to different atoms, because carbon atoms can double-bond to one another. What this does is create the appearance of only being bound to three other atoms, but in actuality four bonds exist. Alkenes are molecules that consist of carbon and hydrogen atoms where one or more pairs of carbon atoms participate in a double bond, which consists of one sigma (σ) and one pi (π) bond. Alkynes are also molecules consisting of carbon and hydrogen atoms, but instead of forming a double bond with only one sigma (σ) and one pi (π) bond, the alkyne has at least one pair of carbon atoms who have a σ and two π bonds -- a triple bond. The carbon-carbon triple bond, then, is a bond in which the carbon atoms share an s and two p orbitals to form just one σ and two π bonds between them. This results in a linear ...
Role of small molecules such as drugs or metabolites in cells is commonly studied by fluorescence microscopy in which a fluorescent label is attached to the molecule. However, fluorescent labels are typically large that often interfere with the normal cellular function of the molecule. To avoid the use of bulky fluorescent labels, we introduce a technique that uses a simple small chemical tag called alkyne consisting of two carbons connected by a triple bond. The alkyne-tagged molecule is imaged using Raman microscopy that detects the strong Raman signal from the CC triple bond stretching vibration (~2120 cm-1). Because the alkyne signal is located in the silent region of the cell (1800-2700 cm-1), it does not interfere with any intrinsic cellular Raman signals. Here, we demonstrate this technique by showing Raman images of an alkyne-tagged component of DNA in a living cell using a slit-scanning confocal Raman microscope. This fast imaging technique is based on a line-shaped focus illumination ...
Bioorthogonal chemistry was pioneered by Dr. Carolyn Bertozzi, a 2017 inductee into the National Inventors Hall of Fame. Her work in Immunology earned her--
Alkenes & Alkynes - Crash Course Chemistry #41 - lesson plan ideas from Spiral. Tagged under: Chemistry (Professional Field),crash ,chemistry,molecule,energy,chemical bonds,Leucippus,atomic theory, nucleus,organic chemistry,Organic Chemistry (Field Of Study),alkanes,isomers,structure,alkenes,alkynes,naming rules,cis trans isomerism,hydrogenation,halogenation,polymerization,triglycerides,names fats
Alkenes & Alkynes - Crash Course Chemistry #41 - lesson plan ideas from Spiral. Tagged under: Chemistry (Professional Field),crash ,chemistry,molecule,energy,chemical bonds,Leucippus,atomic theory, nucleus,organic chemistry,Organic Chemistry (Field Of Study),alkanes,isomers,structure,alkenes,alkynes,naming rules,cis trans isomerism,hydrogenation,halogenation,polymerization,triglycerides,names fats
For the linear alkanes, the internal methylene groups $\left(-\ce{CH2}-\right)$ are considered to be the functional group defining the homologous series:. $$ \ce{H3C-\underline{(\ce{CH2})_n}-CH3}~,~~n\geq 0 \tag{n-alkanes} $$. Alternatively, this series is defined by the absence of any particular functional group other than methyl and methylene.. Ethane, $\ce{C2H6}$ is the member of the series for $n=0$. Technically, one could exclude methane, $\ce{CH4}$, from the series, since it doesnt have two capping methyl groups. However, to my knowledge its usually considered part of the series as a special case.. For the 1-alkenes and 1-alkynes, the double and triple bonded carbons are the functional groups defining the series:. $$ \ce{H3C-(CH2)_n-\underline{\ce{CH=CH2}}} ~,~~n\geq 0 \tag{1-alkenes} $$. $$ \ce{H3C-(CH2)_n-\underline{\ce{C#CH}}} ~,~~n\geq 0 \tag{1-alkynes} $$. Parallel to the alkanes, the shortest "official" members of the two series are technically propene ...
Abstract. Synthesis of 1,3-diene from alkyne and ethylene (1 atm) was improved using a ruthenium NHC carbene complex having a heterocyclic carbene as a ligand. Various 1,3-dienes could be synthesized from alkynes and ethylene.. ...
TY - JOUR. T1 - A frustrated-Lewis-pair approach to catalytic reduction of alkynes to cis-alkenes. AU - Chernichenko, Konstantin. AU - Madarász, Ádám. AU - Pápai, I.. AU - Nieger, Martin. AU - Leskelä, Markku. AU - Repo, Timo. PY - 2013/8. Y1 - 2013/8. N2 - Frustrated Lewis pairs are compounds containing both Lewis acidic and Lewis basic moieties, where the formation of an adduct is prevented by steric hindrance. They are therefore highly reactive, and have been shown to be capable of heterolysis of molecular hydrogen, a property that has led to their use in hydrogenation reactions of polarized multiple bonds. Here, we describe a general approach to the hydrogenation of alkynes to cis-alkenes under mild conditions using the unique ansa-aminohydroborane as a catalyst. Our approach combines several reactions as the elementary steps of the catalytic cycle: hydroboration (substrate binding), heterolytic hydrogen splitting (typical frustrated-Lewis-pair reactivity) and facile intramolecular ...
Alkenes and alkynes can be transformed into almost any other functional group you can name! We will review their nomenclature, and also learn about the vast possibility of reactions using alkenes and alkynes as starting materials.
Alkanes, Alkenes vs Alkynes Alkanes, alkenes and alkynes are all hydrocarbons with different structures and thus different physical and chemical properties.
This Alkenes and Alkynes Worksheet is suitable for Higher Ed. In this alkenes and alkynes worksheet, students name six structures using the IUPAC naming systems and they draw three organic molecules. They also answer a question about a chemical reaction using the Markovnikov rule.
The reaction mechanism for the palladium and amine cocatalyzed carbocyclization of aldehydes with alkynes has been investigated by means of density functional theory calculations and experiments. The Pd/amine cocatalyzed transformation is a carbocyclization of in situ generated enaminynes where the C-C bond-forming step is most likely promoted by a Pd(II) species. Notably, the latent Pd(0)/Pd(II) catalytic redox cycle of this metal/organo cooperative catalytic reaction can be merged with catalytic direct aerobic alcohol oxidation (Pd oxidase catalysis). (Chemical Equation Presented).. ...
Clever Directory lists major producers alkyne services and products in Alberta. It is cleverdirectory.coms goal to provide you a complete list of alkyne companies and organizations. Please use this list of manufacturers to contact the one that interests you.
How to say Alkyne in German. Easily find the right translation for Alkyne from English to German submitted and enhanced by our users.
Author(s): Wang, S; Goronzy, DP; Young, TD; Wattanatorn, N; Stewart, L; Baše, T; Weiss, PS | Abstract: © 2018 American Chemical Society. The reaction aimed at completing and closing the open cages of 1-decaboranethiol self-assembled monolayers (SAMs) on Au{111} with 4-phenyl-1-butyne results in highly ordered monolayers of 4-phenyl-1-butyne. The initially disordered 1-decaboranethiolate changed into ordered (âš3×âš3)R 30° lattices on Au{111} typical of alkyne SAMs, indicating the complete substitution of 1-decaboranethiolate moieties, as determined by nanoscale imaging with scanning tunneling microscopy and X-ray photoelectron spectroscopy. Vibrational spectroscopy results indicate that the process happens gradually and that alkynyl groups are not totally oxidized in the ordered 4-phenyl-1-butyne monolayer.
A number of copolymers between styrene (St) or 4-azidomethylstyrene (N 3St) and 2,3,4,5,6-pentafluorostyrene (FSt) have been prepared by atom-transfer radical polymerization (ATRP) and conventional free radical polymerization (FRP). The mode of monomer alternation in copolymers has been established unambiguously using heteronuclear multiple bond correlation (HMBC) NMR. The degree and nature of monomer alternation was found to be strongly dependent on both the solvent (or lack thereof) and the polymerization initiator. These results are in contrast to previously published studies, which rely primarily on classic analysis of monomer reactivity ratios. We proceeded to independently functionalize the N3St and FSt moieties using orthogonal click chemistries: copper-catalyzed azide-alkyne cycloaddition (CuAAC) and fluoroarene-thiol coupling (FTC). An alternating copolymer bearing -NH2 and -SO3 - functional groups was found to be a competent organocatalyst for a Henry reaction between benzaldehyde ...
A. C. Cardiel, M. C. Benson, L. M. Bishop, K. M. Louis, J. C. Yeager, Y. Tan, R. J. Hamers. "Chemically Directed Assembly of Photoactive Metal Oxide Nanoparticle Heterojunctions via the Copper-Catalyzed Azide-Alkyne Cycloaddition "Click" Reaction." ACS Nano 2012, 6, 310-318. This article was also featured in C&EN on Jan. 23, 2012 in the News of the Week section (Volume 90, Issue 4, p. 8).. ...
Tyrrell, E, Tesfa, KH, Mann, A and Singh, K (2007) Enantioselective alkynylation reactions to substituted benzaldehyde and salicylaldehyde derivatives: The effect of substituents upon the efficiency and enantioselectivity. Synthesis, (10), pp. 1491-1498. ISSN (print) 0039-7881 ...
Terminal alkyne protecting groups[edit]. *Propargyl alcohols in the Favorskii reaction,. *Silyl groups, especially in ...
Alkynes[edit]. Similar to alkenes, alkynes often show strong molecular ion peak. Propargylic cleavage is a most significant ...
Addition of carboxylic acids to alkenes and alkynes[edit]. In the presence of palladium-based catalysts, ethylene, acetic acid ... Carboxylic acids also add across alkynes to give the same products. Silicotungstic acid is used to manufacture ethyl acetate by ...
"Chapter 9: Alkynes". Retrieved 9 June 2017. Shao, L; Shi, M. "N-Bromosuccinimide and Lithium Bromide: An Efficient Combination ...
... , also known as methylpentylethin and oct-2-yne,[1] is a type of alkyne with a triple bond at its second carbon (the '2 ...
Alkynes. CnH2n − 2. Linear alkynes. *Ethyne. *Propyne. *Butyne ...
Alkynes. CnH2n − 2. Linear alkynes. *Ethyne. *Propyne. *Butyne ...
The Thiol-yne reaction (also alkyne hydrothiolation) is an organic reaction between a thiol and an alkyne. The reaction product ... Diphenyl disulphide reacts with alkynes to a 1,2-bis(phenylthio)ethylene. Reported alkynes are ynamides. A photoredox thiol-yne ... Yadav, J. S.; Reddy, B. V. Subba; Raju, A.; Ravindar, K.; Baishya, Gakul (2007). "Hydrothiolation of Unactivated Alkynes ... Weiss, Charles J.; Wobser, Stephen D.; Marks, Tobin J. (2009). "Organoactinide-Mediated Hydrothiolation of Terminal Alkynes ...
Also sometimes designed as ethinyl in compounds (ethinylestradiol, ethisterone (ethinyltestosterone)). See main page alkynes. ...
By hydration of alkynes. Such processes occur via enols and require the presence of an acid and HgSO4. Subsequent enol-keto ... This equilibrium allows ketones to be prepared via the hydration of alkynes. Ketones are far more acidic (pKa ≈ 20) than a ... Ketones containing alkene and alkyne units are often called unsaturated ketones. The most widely used member of this class of ... This reaction always produces a ketone, even with a terminal alkyne. From Weinreb Amides using stoichiometric organometallic ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
Linear alkynes. *C2H2. *C3H4. *C4H6 ...
In 1991, Utimoto reacted gold(III) (NaAuCl4) with alkynes and water. Teles identified a major drawback of this method as Au(III ... Norman, R. O. C.; Parr, W. J. E.; Thomas, C. B. (1976). "The reactions of alkynes, cyclopropanes, and benzene derivatives with ... Cationic gold(I) forms π-complexes with alkene or alkyne bonds, following the Dewar-Chatt-Duncanson model. Gold is certainly ... For instance, Hashmi reported a AuCl3-catalyzed alkyne / furan Diels-Alder reaction - a type of cycloaddition that does not ...
Alkene Alkyne Cycloalkane Higher alkanes "Alkane - Definition from the Compendium of Chemical Terminology". iupac.org. ... "Alkanes". Arora, A. (2006). Hydrocarbons (Alkanes, Alkenes And Alkynes). Discovery Publishing House Pvt. Limited. ISBN ...
The generation of nitrogen gas gives a vinyl carbene G, which via a 1,2-migration forms the desired alkyne H. Dimethyl ( ... A facile synthesis of alkynes". J. Org. Chem. 47 (10): 1837-1845. doi:10.1021/jo00349a007. D. G. Brown; E. J. Velthuisen; J. R ... S. Müller; B. Liepold; G. Roth & H. J. Bestmann (1996). "An Improved One-pot Procedure for the Synthesis of Alkynes from ... Reaction of Bestmann's reagent with aldehydes gives terminal alkynes often in very high yield. The use of the milder potassium ...
... is the addition of an N-H bond of an amine across a carbon-carbon multiple bond of an alkene, alkyne, diene, or ... The four main categories are (1) nucleophilic attack on an alkene alkyne, or allyl ligand and (2) insertion of the alkene into ... Müller, T. E. Beller, M. (1998). "Metal-Initiated Amination of Alkenes and Alkynes". Chemical Reviews. 98 (2): 675-704. doi: ... Pohlki, F., Doye, S. (2003). "The catalytic hydroamination of alkynes". Chemical Society Reviews. 32 (2): 104-114. doi:10.1039/ ...
"Platinum-catalyzed hydrosilylation of alkynes". Organometallics. 10 (10): 3750-3759. doi:10.1021/om00056a055. Moravek, R. T.; ...
Base is not required for electron-deficient alkenes (e.g., derivatives of acrylonitrile) and alkynes. Under free-radical ... "Nucleophilic and free-radical additions of phosphines and phosphine chalcogenides to alkenes and alkynes". Arkivoc. v (5): 12- ...
From alkenes and alkynesEdit. In hydrohalogenation, an alkene reacts with a dry hydrogen halide (HX) like hydrogen chloride ( ... The reaction of alkynes are similar, with the product being a geminal dihalide; once again, Markovnikov's rule is followed. ... Alkynes react similarly, forming the tetrahalo compounds. This is sometimes known as "decolorizing" the halogen, since the ... Similarly, dihaloalkanes can be converted to alkynes.. In related reactions, 1,2-dibromocompounds are debrominated by zinc dust ...
R. J. Rahaim & J. T. Shaw (2008). "Zinc-Catalyzed Silylation of Terminal Alkynes". J. Org. Chem. 73 (7): 2912-2915. doi:10.1021 ... "Silylation of 1-alkynes with chlorosilanes promoted by Zn(OTf)2: an efficient way to the preparation of alkynylsilanes". ...
A terminal alkyne is an alkyne in which one (or both) of the two alkyne carbons is at the end of a chain. ... A terminal alkyne would be better defined as "an alkyne with the formula $\ce{RC_2H}$", differentiating from an internal alkyne ... Like for example pent-2-yne or 2-pentyne is an external alkyne but pent-3-yne is an internal alkyne $\endgroup$ - Caters May 23 ... Alkynes in which the triple bond is between carbons 1 and 2 are commonly referred to as terminal alkynes. ...
Evaluation of biofilm formation on novel copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based resins for dental ...
Chapter 11: Alkenes, Alkynes, and Aromatic Compounds. Owners Manual,Physics Revision Notes For Ordinary Level,Steve Jobs La.New ...
In the alkyne zipper reaction, alkynes are generated from other alkynes by treatment with a strong base. ... Naming alkynes[edit]. In systematic chemical nomenclature, alkynes are named with the Greek prefix system without any ... Terminal and internal alkynes[edit]. Internal alkynes feature carbon substituents on each acetylenic carbon. Symmetrical ... Cycloaddition processes involving alkynes are often catalyzed by metals, e.g. enyne metathesis and alkyne metathesis, which ...
An alkyne trimerisation reaction is a 2+2+2 cyclization reaction in which three molecules of alkyne react to form an arene. The ... Many variations have been developed including cyclization of mixtures of alkynes and alkenes as well as alkynes and nitriles. ... The reactions begin with the formation of metal-alkyne complexes. The combination of two alkynes within the coordination sphere ... If the third alkyne unit is tethered to the first two, three rings can be created in a single step. In the example below in the ...
Alkenes, alkynes, dienes, polyenes. Takashi Tsuno This review briefly covers the literature concerning photochemistry of ... alkenes, alkynes, dienes, and polyenes published during July 2004 and June 2007. ...
... and also learn about the vast possibility of reactions using alkenes and alkynes as starting materials. ... Alkenes and alkynes can be transformed into almost any other functional group you can name! We will review their nomenclature, ... Alkenes and alkynes can be transformed into almost any other functional group you can name! We will review their nomenclature, ... and also learn about the vast possibility of reactions using alkenes and alkynes as starting materials. ...
... a yellow emitting fluorescent alkyne dye. Join researchers using high quality Cy3 alkyne from Abcam and achieve your mission, ... Yellow emitting fluorescent alkyne dye for click chemistry reactions. Analog of Cy3® alkyne. Can be attached to nearly any ... Size-matched alkyne-conjugated cyanine fluorophores to identify differences in protein glycosylation.. Electrophoresis 35:2621- ...
FSc Chemistry Book2, CH 8, LEC 25: Oxidation Reactions of Alkynes. 4 years ago2.7K. views ...
... Malmgren, Joel Stockholm University, Faculty of Science, Department ...
Although some common alkyne names, such as acetylene, are still found in many textbooks, the International Union of Pure and ... The rules for alkynes in this system are identical with those for alkenes, except for the ending. The following rules summarize ... Although some common alkyne names, such as acetylene, are still found in many textbooks, the International Union of Pure and ... The parent name of the alkyne comes from the IUPAC name for the alkane of the same number of carbon atoms, except the ‐ ane ...
... representing the first alkynylsilylation of alkynes via the cleavage of a C(sp)-Si bond by transition-metal catalysis. A highly ... Rhodium-catalyzed intramolecular alkynylsilylation of alkynes is described. The reaction proceeds through syn-insertion by a ... Rhodium-catalyzed intramolecular alkynylsilylation of alkynes R. Shintani, H. Kurata and K. Nozaki, Chem. Commun., 2015, 51, ... Rhodium-catalyzed intramolecular alkynylsilylation of alkynes is described. The reaction proceeds through syn-insertion by a ...
S,R,S)-AHPC-PEG5-Alkyne; Synonym: (2S,4R)-1-((S)-2-(tert-Butyl)-4-oxo-7,10,13,16,19-pentaoxa-3-azadocos-21-ynoyl)-4-hydroxy-N-( ... S,R,S)-AHPC-PEG5-Alkyne Synonym: (2S,4R)-1-((S)-2-(tert-Butyl). -. 4-. oxo-. 7,10,13,16,19-. pentaoxa-. 3-. azadocos-. 21- ... Protein degrader builiding block (S,R,S)-AHPC-PEG5-Alkyne enables the synthesis of molecules for targeted protein degradation ... S,R,S)-AHPC-C6-PEG3-butyl alkyne, ≥95% pricing ... other protein degrader building blocks with a pendant alkyne ...
3. Hydration of Alkynes and Tautomerism. As with alkenes, the addition of water to alkynes requires a strong acid, usually ... The following problems review the chemistry of alkynes. The first question requires you to select one of two starting alkynes ... Addition Reactions of Alkynes. A carbon-carbon triple bond may be located at any unbranched site within a carbon chain or at ... For terminal alkynes the addition of water follows the Markovnikov rule, as in the second example below, and the final product ...
For alkyne nomenclature, the -ene (or -ane) suffix is replaced by -yne. The simplest alkyne, C2H2, goes by the name ethyne or ... Alkynes: Nomenclature Alkynes are similar to alkenes, except they involve a triple bond between two carbons rather than a ... The same rules of alkene nomenclature apply to alkynes. If a double bond and triple bond both appear in the same molecule, the ... Below are two illustrative examples of alkyne nomenclature. Note in the molecule on the right, the double bond wins in the case ...
708d) Optimized Mie Potentials for Phase Equilibria: Application to Noble Gases, Alkanes, Alkynes and Their Mixtures. ... For alkynes, experimental saturated liquid densities are reproduced to within 2% average absolute deviation (AAD), except for 1 ... Transferable united-atom force fields, based on n-6 Mie potentials are presented for noble gases, branched alkanes, and alkynes ... Alkynes, Ethers, and Alcohols. Industrial & Engineering Chemistry Research, 2004. 43(7): p. 1788-1793. ...
... alkenes and alkynes are all hydrocarbons with different structures and thus different physical and chemical properties. ... Alkynes. Alkynes are also unsaturated hydrocarbons; they have one or more triple bonds between the carbon atoms. Their general ... Alkanes, Alkenes vs Alkynes. Alkanes, alkenes and alkynes are all hydrocarbons with different structures and thus different ... They have remained unchanged for millions of years; alkenes are less stable than alkanes and more stable than alkynes; alkynes ...
Synthesis of Isoquinolines from α-Aryl Vinyl Azides and Internal Alkynes by Rh-Cu Bimetallic Cooperation†. ... Synthesis of Isoquinolines from α-Aryl Vinyl Azides and Internal Alkynes by Rh-Cu Bimetallic Cooperation. Angew. Chem., 123: ...
... catalyzed azide-alkyne cycloaddition reaction to form a 1,4-disubstituted triazole. The dendronization reaction proceeded ... Synthesis of Dendronized Poly(l-Glutamate) via Azide-Alkyne Click Chemistry by Peter Perdih. , Andrej Kržan and Ema Žagar * ... Perdih, P.; Kržan, A.; Žagar, E. Synthesis of Dendronized Poly(l-Glutamate) via Azide-Alkyne Click Chemistry. Materials 2016, 9 ... Perdih P, Kržan A, Žagar E. Synthesis of Dendronized Poly(l-Glutamate) via Azide-Alkyne Click Chemistry. Materials. 2016; 9(4): ...
Stereoselective Synthesis of (E)-Alkenyl Sulfones from Alkenes or Alkynes via Copper-Catalyzed Oxidation of Sodium Sulfinates ... Copper-Catalyzed Oxidative Hydrosulfonylation of Alkynes Using Sodium Sulfinates in Air. Nobukazu Taniguchi*. *Department of ... Copper-catalyzed hydrosulfonylations of both terminal and internal alkynes can be carried out using sodium sulfinates in air. ...
... alkenes and alkynes vary? Been searching for like 10 minutes, no luck here. Seems like it varies on a case... ... When comparing alkynes, alkenes, and alkanes of similar molecular weight and structure(unbranched), I am pretty sure alkynes ... When comparing alkynes, alkenes, and alkanes of similar molecular weight and structure(unbranched), I am pretty sure alkynes ... cycloalkanes,alkynes, cis alkenes,trans alkenes,alkanes,terminal alkenes. I just need to post the graph now... ...
... Xiao Zhang, Wen-Zhen Zhang*, Xiang Ren, Lin-Lin Zhang ... propiolic acids was developed by AgI-catalyzed carboxylation of terminal alkynes using carbon dioxide as carboxylative agent ...
In this alkenes and alkynes worksheet, students name six structures using the IUPAC naming systems and they draw three organic ... This Alkenes and Alkynes Worksheet is suitable for Higher Ed. ... In this organic chemistry of alkynes worksheet, students write ... How do we tell organic molecules apart? Discover the basics of alkene and alkyne formulas, bonding, and isomers with a video ... In this organic chemistry of alkynes worksheet, students write the reactions needed to convert a carbon compound to a different ...
Physical properties and nomenclature of alkynes 3. Preparation and use of alkynes4. Addition to triple bonds. ... Alkynes -. .1 introduction .2 nomenclature of alkynes .3 physical properties of alkynes .4 preparation of alkynes .5 reactions ... Chapter 9 Alkynes -Organic chemistry , 6 th edition l. g. wade, jr. chapter 9 alkynes. introduction. alkynes contain a triple ... Chapter 9 Alkynes -Organic chemistry , 6 th edition l. g. wade, jr. chapter 9 alkynes. introduction. alkynes contain a triple ...
Chemical safety goggles. Compatible chemical resistant gloves. NIOSH/MSHA approved respirator. Mechanical exhaust (fume hood). Avoid inhalation. Avoid contact with eyes, skin and clothing. Wash thoroughly after handling ...
  • Subsequent transfer of hydrogen to the adsorbed alkyne proceeds slowly, relative to the corresponding hydrogen transfer to an adsorbed alkene molecule. (msu.edu)
  • The alkyne-tagged molecule is imaged using Raman microscopy that detects the strong Raman signal from the CC triple bond stretching vibration (~2120 cm -1 ). (spie.org)
  • Masanobu Uchiyama and Ryo Takita from the RIKEN Center for Sustainable Resource Science and researchers from the University of Tokyo have now devised a method for selectively adding boron atoms to opposite sides of an alkyne molecule. (phys.org)
  • When additional atomic groups are added to an organic compound such as an alkyne, which has two carbon -carbon triple bond sites, the added groups can attach to the triple bond sites such that they are oriented to one side of the molecule to form what is known as a cis configuration, or oriented in opposite directions to afford a trans structure. (phys.org)
  • There are lots of types of formulas and each of them should be used in different situations.This is shown on alkenes and alkynes.There is also a way how to resize a molecule shown. (zirael.org)
  • A symmetrical alkyne is an alkyne in whose molecule the triply bonded carbon atoms bear the same ligands. (libretexts.org)
  • In the language of valence bond theory, the carbon atoms in an alkyne bond are sp hybridized: they each have two unhybridized p orbitals and two sp hybrid orbitals. (wikipedia.org)
  • The parent name of the alkyne comes from the IUPAC name for the alkane of the same number of carbon atoms, except the ‐ ane ending is changed to ‐ yne to signify the presence of a triple bond. (cliffsnotes.com)
  • 3. The position of the triple bond is indicated by placing the lower of the pair of numbers assigned to the triple‐bonded carbon atoms in front of the name of the alkyne. (cliffsnotes.com)
  • Figure 1: The three-dimensional structure of trans-diborylated alkyne, showing the position of boron (yellow), oxygen (red), carbon (gray) and hydrogen (white) atoms. (phys.org)
  • Uchiyama's team investigated whether diboron-two boron atoms -could be selectively added to an alkyne to form a trans arrangement (Fig. 1). (phys.org)
  • Treatment of compound A with sodium amide converts it to compound B. Compound B on ozonol- ysis gives a diacid that retains all the carbon atoms of B. Compound B must therefore be a cyclic alkyne, formed by an intramolecular alkylation. (coursehero.com)
  • Although there are many reports on alkyne transformations, one recent development in this area has been the reaction of alkynes with tertiary alkyl electrophiles to produce functionalized quaternary carbon atoms via addition [5-or coupling [11-. (beilstein-journals.org)
  • Functionalizingpentacyclo[5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane-8-11-oneand 1-phenyl-pentacyclo[5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane-8-11-one can be easily accomplished by using the alcohols of various alkynes and alkenes. (scielo.org.za)
  • identify the reagents needed to convert a given alkyne to a given ketone. (libretexts.org)
  • identify the reagents, the alkyne, or both, needed to prepare a given ketone or a given cis alkene through a vinylic borane intermediate. (libretexts.org)
  • This fact, together with the capacity of I2 to activate both alkyne carbons towards nucleophilic attack, makes I2 the reagent of choice (superior to iodonium reagents) for iodocyclizations of resistant substrates. (edu.au)
  • Similarly, Zhu's group has reported that the reaction of an alkyne and an α-bromocarbonyl compound furnishes a highly functionalized 1,3-enyne compound via ATRA followed by an alkynylation reaction , but both Pd and Cu are required as catalysts in that case. (beilstein-journals.org)
  • write an equation for the reaction of an alkyne with borane. (libretexts.org)
  • Other methods for the direct formation of aromatic rings from substituted, unsaturated precursors include the Dötz reaction, palladium-catalyzed [4+benzannulation of enynes with alkynes, and Lewis-acid-mediated [4+cycloaddition of enynes with alkynes. (wikipedia.org)
  • Cyclization of transient benzyne species with alkynes, catalyzed by palladium, can also produce substituted aromatic compounds. (wikipedia.org)
  • The reaction mechanism for the palladium and amine cocatalyzed carbocyclization of aldehydes with alkynes has been investigated by means of density functional theory calculations and experiments. (diva-portal.org)
  • A palladium-catalyzed multicomponent reaction of alkynes, carboxylic acids, and isocyanides has been developed with the assistance of silver salt under mild conditions. (figshare.com)
  • Alkynes can be selectively hydrogenated into alkenes on solid palladium catalysts. (gla.ac.uk)
  • To address this critical need, a novel brominated coumarin azide was used to tag alkynes and detect alkyne-conjugated biomolecules. (figshare.com)
  • Here we highlight our recent results of the application of ring-closing metathesis and ring-closing alkyne metathesis (RCAM) in biologically relevant biomolecules in order to introduce alkene- and/or alkyne-bridges as novel covalent constraints for stabilizing their bioactive conformation and increasing their metabolic stability. (gla.ac.uk)
  • Alkyne has 4 fewer hydrogens than an alkane. (slideserve.com)
  • The chiral column high-performance liquid chromatography (HPLC) method in general could not be directly used to resolve such substrates, since the differentiation of the alkyne segment with the other alkane/alkene segment is not significant in the stationary phase, and the alkyne group is not a good UV chromophore. (mdpi.com)
  • Moreover, the reaction of α-bromocarbonyl compound 2 and an alkyne 4 possessing a carboxamide moiety undergoes tandem alkyl radical addition/C-H coupling to produce indolinone derivative 5 . (beilstein-journals.org)
  • Alkynes are generally prepared by dehydrohalogenation of vicinal alkyl dihalides or the reaction of metal acetylides with primary alkyl halides. (chemeurope.com)
  • In this chapter, we shall discuss how alkynes are prepared via elimination reactions and by adding alkyl group(s) to the smaller ethyne unit. (tutorsglobe.com)
  • In this account, our two approaches to the metal-free synthesis of oxazoles by means of a peculiar activation of alkynes by iodine species is described with the related contexts. (eurekaselect.com)
  • predict the structure of the ketone formed when a given alkyne reacts with sulfuric acid in the presence of mercury(II) sulfate. (libretexts.org)
  • Possible explanations involve the two π-bonds in the alkyne delocalising, which would reduce the energy of the π-system [ citation needed ] or the stability of the intermediates during the reaction. (wikipedia.org)
  • Methods to form two carbon-boron bonds on the same side of an alkyne, a procedure called cis-diborylation, have been described previously," explains Uchiyama, "but trans-diborylation has not been possible. (phys.org)
  • The triple bond of alkynes consists of one sigma bond and two pie bonds, which are perpendicular to each other. (assignmenthelp.net)
  • Concentrating on alkyne and allene cyclisation and upon reaction mechanisms postulated on the basis of empirical and theoretical results, we have examined the coordination of gold fragments to triple bonds, the modification of gold(I) precatalysts to effect specific reaction pathways or enantioselectivity and the isolation of coordinated intermediates or model compounds thereof. (sun.ac.za)
  • Alkynes possess 2 pi bonds allowing for a full or partial reduction. (leah4sci.com)
  • Organic chemistry is difficult, those who study it have alkynes of trouble" was posted on Twitter on November 3, 2011. (barrypopik.com)
  • From what I've heard, organic chemistry students have alkynes of trouble with the class. (barrypopik.com)
  • Organic Chemistry is very difficult, those who take it have Alkynes of trouble. (barrypopik.com)
  • Akio Saito*, "Hypervalent Iodine-Mediated/Catalyzed Oxidative Cycloisomerization/Annulation of Alkynes for Metal-Free Synthesis of Oxazoles", Current Organic Chemistry (2020) 24: 1. (eurekaselect.com)
  • Alkyne reactions typically mark the turning point between basic organic chemistry and this just got real! (leah4sci.com)
  • The resulting polymers, called polyacetylenes (which do not contain alkyne units) are conjugated and can exhibit semiconducting properties. (wikipedia.org)
  • By contrast, I+ gives unsymmetrical, open iodovinyl cations, in which only one carbon is activated toward nucleophilic attack, especially for polarized alkynes. (edu.au)