Cyclic AMIDES formed from aminocarboxylic acids by the elimination of water. Lactims are the enol forms of lactams.
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)
Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
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.
A 13-amino acid peptide derived from proteolytic cleavage of ADRENOCORTICOTROPIC HORMONE, the N-terminal segment of ACTH. ACTH (1-13) is amidated at the C-terminal to form ACTH (1-13)NH2 which in turn is acetylated to form alpha-MSH in the secretory granules. Alpha-MSH stimulates the synthesis and distribution of MELANIN in MELANOCYTES in mammals and MELANOPHORES in lower vertebrates.
A class of organic compounds containing a ring structure made up of more than one kind of atom, usually carbon plus another atom. The ring structure can be aromatic or nonaromatic.
Four-membered cyclic AMIDES, best known for the PENICILLINS based on a bicyclo-thiazolidine, as well as the CEPHALOSPORINS based on a bicyclo-thiazine, and including monocyclic MONOBACTAMS. The BETA-LACTAMASES hydrolyze the beta lactam ring, accounting for BETA-LACTAM RESISTANCE of infective bacteria.
Compounds consisting of glucosamine and lactate joined by an ether linkage. They occur naturally as N-acetyl derivatives in peptidoglycan, the characteristic polysaccharide composing bacterial cell walls. (From Dorland, 28th ed)
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.
Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)
A cyclohexylamido analog of PENICILLANIC ACID.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
A plant genus of the family CAPPARACEAE that contains cleogynol and 15alpha-acetoxycleomblynol (dammaranes) and 1-epibrachyacarpone (a triterpene), and ISOTHIOCYANATES.
A family of G-protein-coupled receptors that have specificity for MELANOCYTE-STIMULATING HORMONES and ADRENOCORTICOTROPIC HORMONE. There are several subtypes of melanocortin receptors, each having a distinct ligand specificity profile and tissue localization.
The characteristic three-dimensional shape of a molecule.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)
A group of antibiotic aminoglycosides differing only in the number of repeating residues in the peptide side chain. They are produced by Streptomyces and Actinomyces and may have broad spectrum antimicrobial and some antiviral properties.
Organic compounds containing the carboxy group (-COOH). This group of compounds includes amino acids and fatty acids. Carboxylic acids can be saturated, unsaturated, or aromatic.
Substances that reduce the growth or reproduction of BACTERIA.
A frequent complication of drug therapy for microbial infection. It may result from opportunistic colonization following immunosuppression by the primary pathogen and can be influenced by the time interval between infections, microbial physiology, or host resistance. Experimental challenge and in vitro models are sometimes used in virulence and infectivity studies.
A separation technique which combines LIQUID CHROMATOGRAPHY and CAPILLARY ELECTROPHORESIS.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Acyclic branched or unbranched hydrocarbons having two carbon-carbon double bonds.
The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include pharmacokinetics, dosage analysis, or drug administration analysis.
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
Inorganic or organic compounds derived from phosphine (PH3) by the replacement of H atoms. (From Grant & Hackh's Chemical Dictionary, 5th ed)
A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
Alkyl compounds containing a hydroxyl group. They are classified according to relation of the carbon atom: primary alcohols, R-CH2OH; secondary alcohols, R2-CHOH; tertiary alcohols, R3-COH. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Alkaloids extracted from various species of Cinchona.
Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).
A class of saturated compounds consisting of two rings only, having two or more atoms in common, containing at least one hetero atom, and that take the name of an open chain hydrocarbon containing the same total number of atoms. (From Riguady et al., Nomenclature of Organic Chemistry, 1979, p31)
Addition of hydrogen to a compound, especially to an unsaturated fat or fatty acid. (From Stedman, 26th ed)
Glycosylated compounds in which there is an amino substituent on the glycoside. Some of them are clinically important ANTIBIOTICS.
An analytical technique for resolution of a chemical mixture into its component compounds. Compounds are separated on an adsorbent paper (stationary phase) by their varied degree of solubility/mobility in the eluting solvent (mobile phase).
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.
A hybrid separation technique combining both chromatographic and electrophoretic separation principles. While the method was invented to separate neutral species, it can also be applied to charged molecules such as small peptides.
A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
Organic nitrogenous bases. Many alkaloids of medical importance occur in the animal and vegetable kingdoms, and some have been synthesized. (Grant & Hackh's Chemical Dictionary, 5th ed)
Unstable isotopes of indium that decay or disintegrate emitting radiation. In atoms with atomic weights 106-112, 113m, 114, and 116-124 are radioactive indium isotopes.
A publication issued at stated, more or less regular, intervals.
A quantitative measure of the frequency on average with which articles in a journal have been cited in a given period of time.
"The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.
The use of statistical methods in the analysis of a body of literature to reveal the historical development of subject fields and patterns of authorship, publication, and use. Formerly called statistical bibliography. (from The ALA Glossary of Library and Information Science, 1983)
The evaluation by experts of the quality and pertinence of research or research proposals of other experts in the same field. Peer review is used by editors in deciding which submissions warrant publication, by granting agencies to determine which proposals should be funded, and by academic institutions in tenure decisions.
The study of the structure, growth, function, genetics, and reproduction of bacteria, and BACTERIAL INFECTIONS.
The profession of writing. Also the identity of the writer as the creator of a literary production.
Park, Yoonsu; Chang, Sukbok (2019-02-18). "Asymmetric formation of γ-lactams via C-H amidation enabled by chiral hydrogen-bond- ... They later published selective formation of gamma-lactams via C-H amidation with this type of nucleophile. 2019: Korea Best ... "Selective formation of γ-lactams via C-H amidation enabled by tailored iridium catalysts". Science. 359 (6379): 1016-1021. doi: ...
... lycoperdic acid through an endo selective hydroxylation of the chiral bicyclic lactam enolate with MoOPH". Tetrahedron. 58 (48 ...
Chiral resolution using alpha-phenylethylamine gave optically active 47. Oxidation of the double bond with chromic acid gave ... This compound resisted ring-opening of the lactam group due to incorrect stereochemistry of the propionic ester side-chain. The ... A total of nine carbon atoms on the corrin frame are chiral, adding another challenge to the synthesis. The Woodward/ ... The starting material for the synthesis of ring C was chiral (+)-camphorquinone 38 which can be converted to the acetoxy ...
Chiral induction has been demonstrated with many other chiral ketones and ketones with chiral auxiliaries, including SAMP and ... spirocylic oxaziridines undergo ring expansions to the corresponding lactam. The migrating substituent is determined by a ... oxidation of chiral imines and oxidation of imines with chiral peracids may yield enantiopure oxaziridines. Some oxaziridines ... Chiral camphorsulfonyloxaziridines proved useful in the syntheses of complex products, such as taxol which is marketed as a ...
The absolute stereochemistry at several chiral centers has been determined as of 2009. In 2012, a three-dimensional solution ... Bottromycin is structurally distinct from both vancomycin, a glycopeptide antibiotic, and methicillin, a beta-lactam antibiotic ...
For example medium sized lactams can be synthesized in the chiral environment of an ene-reductase through a reductive, baldwin ... In biocatalyzed asymmetric synthesis, a non-chiral unit becomes chiral in such a way that the different possible stereoisomers ... The chirality is introduced into the substrate by influence of enzyme, which is chiral. Yeast is a biocatalyst for the ... Enantioselectivity: Since almost all enzymes are made from L-amino acids, enzymes are chiral catalysts. As a consequence, any ...
All are chiral. (R)-γ-caprolactone is a component of floral scents and of the aromas of some fruits and vegetables, and is also ... Caprolactone is treated with ammonia at elevated temperatures to give the lactam: (CH2)5CO2 + NH3 → (CH2)5C(O)NH + H2O ...
... quinones and amides catalyzed by chiral Lewis acids and nucleophiles; such as catalytic, asymmetric synthesis of β-lactams; and ... He presented the mechanism of the β-lactam development with proton sponge as the stoichiometric base, and also discussed the ... Evans, David A.; Lectka, Thomas; Miller, Scott J. (October 29, 1993). "Bis(imine)-copper(II) complexes as chiral lewis acid ... lactams. During his studies at Cornell University from 1986 until 1991, Lectka focused on the design, synthesis, and study of ...
... and the Nazarov reaction has been performed catalytically using chiral Lewis acids, Brønsted acids and chiral amines. IUPAC ... The most commonly studied reactions in this field are the 4π Staudinger β-lactam synthesis and the 4π Nazarov reaction; ... asymmetric catalysis of both reactions have been controlled by use of a chiral auxiliary, ...
Staudinger synthesis of β-lactams and many more. Chiral DMAP analogues are used in kinetic resolution experiments of mainly ... Ryan P. Wurz (2007). "Chiral Dialkylamine Catalysts in Asymmetric Synthesis". Chem. Rev. 107 (12): 5570-5595. doi:10.1021/ ...
For example, cyclo(L-Phe-L-Phe) 1 gives the chiral piperazine (2S,5S)-dibenzylpiperazine 2. Reaction of the lactam-derived enol ... These small, conformationally rigid, chiral templates have multiple H-bond acceptor and donor functionality and have multiple ... The most common method for alkylation of the lactam nitrogen of 2,5-diketopiperazines is based on the use of sodium hydride as ... Reduction of the carbonyl groups of chiral 2,5-diketopiperazine with lithium aluminium hydride (LiAlH4) cleanly gives the ...
Rao is the pioneer of Chiral synthesis and technology in India and is known to have synthesized compounds of high structural ... diversity like Coriolic acid, Dimorphicolic acid, β-Lactam antibiotics, Azamacrolides, Camptothecin, Andrimid and Chrysanthemic ... Elias James Corey Institute of Chemical Technology Chiral synthesis National Chemical Laboratory Indian Institute of Chemical ...
Propargyl substituted bislactim ethyl ether is generated by using Schöllkopf chiral auxiliary bis lactam ether with n-BuLi, THF ...
... lactam, macrolide and tetracycline antibiotics), which was accomplished by using carbohydrates as chiral sources in their ...
In the 1998 Keuhne synthesis of chiral (−)-strychnine the starting material was derived from chiral tryptophan. In the Rawal ... The three ester groups were hydrolyzed using iodotrimethylsilane forming pentacyclic lactam 5 after a methanol quench in a ... The overall yield (10%) is to date the largest of any of the published methods In the Bosch synthesis of (1999, chiral) the ... The Shibasaki synthesis ((-) chiral, 2002) was a second published method in strychnine total synthesis using an asymmetric ...
Consequent lactam-ring opening and functionalization were expected to give Taxol. Similarly, molecules of the fusicoccin family ... the general ease to create the four tertiary chiral centers is still noteworthy. Use of [4+4] photocycloaddition need not be ... effect of ring substituents and chiral ketal". Tetrahedron Lett. 50: 1188-1192. doi:10.1016/j.tetlet.2008.12.117. Song, D.; ...
Ojima lactam Valine as a Chiral auxiliary in the Schöllkopf method Key Chiral Auxiliary Applications (Second Edition)(ed.: Roos ... Chiral auxiliaries were introduced by Elias James Corey in 1975 with chiral 8-phenylmenthol and by Barry Trost in 1980 with ... Chiral α,β-Unsaturated Carboximides as Practical Chiral Acrylate and Crotonate Dienophile Synthons". J. Am. Chem. Soc. 106 (15 ... Condensation, alkylation, and cleavage with SAMP/RAMP chiral auxiliaries Chiral auxiliaries are generally reliable and ...
This lactam was first synthesized by Iwao Ojima. The organic synthesis is an illustration of asymmetric synthesis via a chiral ... in the β-lactam a chiral auxiliary is used in the enolate synthesis. The enolate synthesis starts from glycolic acid. The ... by an intramolecular nucleophilic acyl substitution of the amine with expulsion of the chiral auxiliary to the cis-lactam. The ... The Ojima lactam is an organic compound of some importance in the commercial production of Taxol. ...
Synthesis of Chiral 7-Oxa-2-azabicyclo[2.2.1]heptane and 8-Oxa-6-azabicyclo[3.2.1]octane Ring Systems". J. Org. Chem. 68 (3): ... reported that the amidyl radical intermediates, produced by photolysis of medium-sized lactams, e.g. 82 in the presence of PhI( ... E. Suárez and co-workers also applied their methodology in the synthesis of chiral 8-oxa-6-azabicyclo[3.2.1]-octane 85 and 7- ... "Hypervalent organoiodine reagents in the transannular functionalisation of medium-sized lactams: synthesis of 1-azabicyclo ...
Achiral ketenes and imines, in the presence of a chiral nucleophilic catalyst, are allowed to react to make β-lactams in high ... Subsequent ring closure leads to the formation of the β-lactam and the regeneration of the chiral nucleophilic organocatalyst. ... Unlike the Staudinger β-lactam synthesis, the umpolung ketene in the Lectka β-lactam synthesis behaves as the nucleophile ... Mechanistic evidence for imine activation working in tandem with chiral enolate formation in the synthesis of beta-lactams". J ...
With chiral biphenols Schaus and Lou of Boston University reported the following reaction, in which chiral α-amino acids with ... Hydroxypyrrolidines and Hydroxy-γ- and δ-lactams have been shown to react very diastereoselectively, with good to excellent ... With chiral N-acyliminium ions Chiral N-acyliminium ion "starting materials" are generally prepared by in-situ dehydration of ... With chiral amine nucleophile Generally speaking, when chiral amine is used in Petasis coupling, the stereochemical outcome of ...
Many methods have been developed for influencing the stereoselectivity of the Diels-Alder reaction, such as the use of chiral ... Chlorosulfonyl isocyanate can be utilized as a dienophile to prepare Vince lactam. Lewis acids such as zinc chloride, boron ... Evans, D. A.; Chapman, K. T.; Bisaha, J. (1988). "Asymmetric Diels-Alder cycloaddition reactions with chiral α,β-unsaturated N- ... Corey, E. J.; Shibata, T.; Lee, T. W. (2002). "Asymmetric Diels-Alder reactions catalyzed by a triflic acid activated chiral ...
6) Chiral auxiliaries have been employed on either the imino nitrogen or imino carbon to effect diastereoselection. (5) ... Synthesis of alpha,beta-unsaturated delta-valerolactones and -lactams". Org. Lett. 1 (4): 641-4. doi:10.1021/ol9907217. PMID ... Corey, E. J.; Yuen, P.-W. (1989). "A short, stereospecific route to chiral trans-2,6-disubstituted quinuclidines". Tetrahedron ... Use of amino-acid-based chiral auxiliaries, for instance, leads to good diastereoselectivities in reactions of cyclopentadiene ...
... s react, thermally, with ketenes in [2+2] cycloadditions to form β-lactams in the Staudinger synthesis. An imine can be ... Since imines derived from unsymmetrical ketones are prochiral, their reduction is a useful method for the synthesis of chiral ... NBn and PhSiH2 in a hydrosilylation with chiral ligand DIOP and rhodium catalyst (RhCl(CH2CH2)2)2. Many systems have since been ... Applications to the Synthesis of Tetrahydropyrimidines and β-Lactams". Organic Letters. 16 (3): 740-743. doi:10.1021/ol403427s ...
Biocatalysis Catalysis Chemosensors Chiral synthesis Flow chemistry Green chemistry Mechanochemistry Photoredox catalysis Acids ... Xylenes Aryl halides Carbohydrates Sugar Carbonyl compounds Acid anhydride Acyl halides Acyl chlorides Aldehydes Amides Lactams ...
This compound is commercially available as a single enantiomer and the single chiral group present in this molecule is able to ... Taxol resulted from the tail addition of the Ojima lactam to alcohol 51, which is baccatin III (the original target molecule of ... Protection: See: Ojima lactam Deprotection: hydrogen fluoride, pyridine, and acetonitrile The TES protecting group that was ... Subsequent reduction using sodium borohydride produced alcohol 51 . Reaction of this alcohol with the Ojima lactam 52 and a ...
The protected group (leaving group) is not directly attached to this chiral carbon atom, however has been shown to be able to ... 2. Intramolecular Insertions Leading to Polycyclic Lactams". Journal of the American Chemical Society. 115 (23): 10568-10580. ... The phenacyl moiety itself contains one chiral carbon atom in the backbone. ... Kammath, Viju Balachandran (2012). "Photoremovable chiral auxiliary". Photochemical and Photobiological Sciences. 11 (9): 500- ...
The ester 3 is converted into an amide in 4 by reaction with ammonia and the next step to lactam 5 is an iodolactamization with ... Roche has other routes to oseltamivir that do not involve the use of (−)-shikimic acid as a chiral pool starting material, such ... and a chiral catalyst to the azide 2. The amide group is protected as a BOC group with Boc anhydride and DMAP in 3 and ...
Finally, Stephen G. Davies of Oxford has designed a chiral auxiliary that combines the functionality of the Weinreb amide with ... various lactams and lactones, sulfonates, sulfinates, and phosphonate esters. A wide variety of nucleophiles can be used in ... Chiral Weinreb Amide Equivalents", The Journal of Organic Chemistry, 75 (4): 1214-1227, doi:10.1021/jo902499s, PMID 20095549. ...
... s react, thermally, with ketenes in [2+2] cycloadditions to form β-lactams in the Staudinger synthesis. An imine can be ... Since imines derived from unsymmetrical ketones are prochiral, their reduction is a useful method for the synthesis of chiral ... Langlois, N (1973). "Synthese asymetrique d'amines par hydrosilylation d'imines catalysee par un complexe chiral du rhodium". ... NBn and PhSiH2 in a hydrosilylation with chiral ligand DIOP and rhodium catalyst (RhCl(CH2CH2)2)2.[18] Many systems have since ...
X-ray diffraction has been used for the identification of antibiotic drugs such as: eight β-lactam (ampicillin sodium, ... For example, reflection symmetries cannot be observed in chiral molecules; thus, only 65 space groups of 230 possible are ... allowed for protein molecules which are almost always chiral. Indexing is generally accomplished using an autoindexing routine. ... "X-ray powder diffraction patterns for certain beta-lactam, tetracycline and macrolide antibiotic drugs". Analytical Sciences ...
It is a chiral molecule and thus has two potential configurations, as (R)- and (S)-enantiomers.[13] ... β-Lactams (e.g., penicillins, cephalosporins, carbapenems). *Basmisanil. *Bemegride. *Bicyclic phosphates (TBPS, TBPO, IPTBO) ...
Many natural phenols are chiral. An example of such molecules is catechin. Cavicularin is an unusual macrocycle because it was ... "Lead identification of conformationally restricted β-lactam type combretastatin analogues: Synthesis, antiproliferative ...
... often have chiral centers.[25] An example of such a molecule is catechin.[citation needed] Cavicularin is an unusual ... "Lead identification of conformationally restricted β-lactam type combretastatin analogues: Synthesis, antiproliferative ...
Li, M; Wu, A; Zhou, P. A concise synthesis of (+)-pancratistatin using pinitol as a chiral building block. Tetrahedron Lett. ... The synthesis was completed by deprotection of the amine and a Cobalt catalzyed CO insertion to furnish the lactam. (+)- ...
described chiral oligomers of pentenoic amides (COPAs) that can be used to construct mass encoded OBOC libraries. Kerr et al. ... The formed imines were then derivatized to generate 4-thiazolidinones, B-lactams, and pyrrolidines. The use of solid-phase ...
In a time when asymmetric reactions largely relied on chiral auxiliaries to be covalently bound to the reactants, tin(II) ... the others from its use of L-serine as a starting material and for being the only total synthesis not to use the Ojima lactam ... Tin(II) goes a step further by having multiple empty orbitals, allowing it to coordinate chiral ligands and induce ... enolates formed from chiral diamine ligands derived from L-proline could achieve over 90% ee. In 1975, Mukaiyama reported that ...
He has contributed extensively to the synthesis of β-lactams using alkenyl anions, ynolates, novel isocyanates, iron ... "Chiral bis-Acetal Porphyrazines as Near-infrared Optical Agents for Detection and Treatment of Cancer". Photochemistry and ... "Chiral porphyrazine near-IR optical imaging agent exhibiting preferential tumor accumulation". Proceedings of the National ...
... is chiral but is mainly encountered as the racemate. 2-Methylglutaronitrile is a by-product of the ... US 5814508, R. DiCosimo, R.D. Fallon, J.E. Gavagan, F.E. Herkes, "Preparation of lactams from aliphatic α, ω-dinitriles", ...
Thus, β-lactams are structural elements of penicillin and cephalosporin antibiotics, imidazoles are found both in modern ... This is particularly the case in the synthesis of molecules with chiral centres. Here, it is possible to substitute the ... In this context, the ability to synthesize chiral molecules has become an important competency. Two types of processes are used ... About 2/3 of chiral products produced on large industrial scale are already made using biocatalysis. In the manufacture of fine ...
Asymmetric formation of γ-lactams via C-H amidation enabled by chiral hydrogen-bond-donor catalysts Chiral γ-lactams are of ... Now, Park and Chang report an iridium-based catalyst system for the production of chiral γ-lactams from an abundant feedstock ... Asymmetric catalysis is a type of catalysis in which a chiral catalyst directs the formation of a chiral compound such that ... Phosphoric acid-catalyzed atroposelective construction of axially chiral arylpyrroles Axially chiral arylpyrroles are ...
CH9910891Chiral Synthesis of a New Protected γ-Lactam Bridged Dipeptide. NJ Ede, ID Rae and MTW Hearn ...
Erratum: Corrigendum to Stereoselective synthesis of an optically active axially chiral lactam and its reaction with some ... Stereoselective synthesis of an optically active axially chiral lactam and its reaction with some electrophiles (Tetrahedron ( ...
Open-chain building blocks from chiral lactams. Enantioselective synthesis of macrocyclic nitrogen-containing natural products ... phenylglycinol-derived oxazolopiperidone lactams brought about the reductive opening of both the oxazolidine and lactam rings, ... 9. The approach we have developed significantly expands the potential of phenylglycinol-derived d-lactams, which have been ... 1. (R)-Phenylglycinol-derived oxazolopiperidone lactams can be converted to enantiopure open-chain amino ester scaffolds by ...
In summary, C and ECg enhanced the antibacterial effect of β-lactam antibiotics against MRSA in vitro and in vivo, which might ... Qidong, Y.; Guoqiang, L. Chiral Drugs: Research and Evaluation; Chemical Industry Press: Beijing, China, 2011. [Google Scholar] ... These β-lactam antibiotics are both classic and representative β-lactam antibiotics in the clinic. However, they cannot be used ... The main resistance mechanisms of MRSA to the β-lactam antibiotics are a large expression of β-lactamase to destroy β-lactams ...
Diastereoselective radical addition to γ-alkyl-α-methylene-γ-butyrolactams and the synthesis of a chiral pyroglutamic acid ... γ-lactam and reported that the N-unsubstituted lactam yields cis-α,γ-disubstituted lactams using (Me3Si)3SiH under UV ... Here, we report cis- and trans-stereoselective radical additions to α-methylene-γ-alkyl- γ-lactams and the synthesis of chiral ... However, the most commonly used methods for synthesizing chiral γ-lactams are based on the cyclization or cycloaddition of N- ...
Synthesis of Chiral β-Lactam, a Constituent or Precursor of Important Drugs. Gautam Bhattacharya. Chemistry. Journal of Arts, ...
Process for Preparation of Chiral Y-Lactams 1870/DEL/2010 Dr. Manas Kumar Ghorai, Mr. Deo Prakash Tiwari Patent Filed ...
Enantioselective Staudinger synthesis of beta-lactams catalyzed by a planar-chiral nucleophile. ... Enantioselective addition of amines to ketenes catalyzed by a planar-chiral derivative of PPY: possible intervention of chiral ... Catalytic asymmetric Staudinger reactions to form beta-lactams: an unanticipated dependence of diastereoselectivity on the ...
David Konas Selective electrophilic flourination of a chiral lactam ring. Presenter: Title: Co-author:. William Hendrixson ...
"Synthesis of chiral .beta.-lactams using L-ascorbic acid"; Journal of Organic Chemistry (1985), 50(19), 3462-3467(compound 12), ...
An updated guide to the most current information available for determining how to use NMR spectroscopy to differentiate chiral ... 6.2 Lactams and Lactam-Like Compounds 178. 6.3 Aldehydes 184. 6.4 Ketones 188 ... An updated guide to the most current information available for determining how to use NMR spectroscopy to differentiate chiral ... Differentiation of Chiral Compounds Using NMR Spectroscopy offers a thoroughly revised second edition to the essential volume ...
... which comprises subjecting a β-lactam compound represented by the formula: ##STR2## wherein Ar, R1 and R2 have the same ... Process for the production of chiral hydroxy-β-lactams and hydroxyamino acids derived therefrom. ... The β-lactam compound of the above formula (I) which is used as a starting material in the present process can readily be ... which comprises subjecting a β-lactam compound represented by the formula ##STR6## wherein Ar, R1 and R2 have the same meanings ...
Achiral ketenes and imines, in the presence of a chiral nucleophilic catalyst, are allowed to react to make β-lactams in high ... Subsequent ring closure leads to the formation of the β-lactam and the regeneration of the chiral nucleophilic organocatalyst. ... Unlike the Staudinger β-lactam synthesis, the umpolung ketene in the Lectka β-lactam synthesis behaves as the nucleophile ... Mechanistic evidence for imine activation working in tandem with chiral enolate formation in the synthesis of beta-lactams". J ...
Chiral resolution using alpha-phenylethylamine gave optically active 47. Oxidation of the double bond with chromic acid gave ... This compound resisted ring-opening of the lactam group due to incorrect stereochemistry of the propionic ester side-chain. The ... A total of nine carbon atoms on the corrin frame are chiral, adding another challenge to the synthesis. The Woodward/ ... The starting material for the synthesis of ring C was chiral (+)-camphorquinone 38 which can be converted to the acetoxy ...
Thus an optically active compound having plural chiral centers.Further, an optically active 2,5,6-substituted-1,3-dioxan-4-one ... lactam compounds through acid amide compounds. The .beta.-lactam compoundscan be starting materials for producing carbapenem ... The compounds of the present invention can be converted to various useful compounds due to the plural chiral centers.. The ... 1. A process for producing an optically active compound having plural chiral centers which comprises causing an ester to act on ...
Chiral N-heterocyclic carbene ligands based on a biisoquinoline template. Dalton Transactions(41), pp. 4922-4925. (10.1039/ ... A Convenient Protocol for the Alkylidenation of Lactams. Synthesis 2006(7), pp. 1162-1170. (10.1055/s-2006-926390) ... Chiral N-heterocyclic carbene ligands based on a biisoquinoline template. Dalton Transactions(41), pp. 4922-4925. (10.1039/ ... A Convenient Protocol for the Alkylidenation of Lactams. Synthesis 2006(7), pp. 1162-1170. (10.1055/s-2006-926390) ...
This lactam was first synthesized by Iwao Ojima. The organic synthesis is an illustration of asymmetric synthesis via a chiral ... in the β-lactam a chiral auxiliary is used in the enolate synthesis. The enolate synthesis starts from glycolic acid. The ... by an intramolecular nucleophilic acyl substitution of the amine with expulsion of the chiral auxiliary to the cis-lactam. The ... The Ojima lactam is an organic compound of some importance in the commercial production of Taxol. ...
Structure-directed reversion in the pi-facial stereoselective alkylation of chiral bicyclic lactams. The Journal of organic ...
For use in the synthesis of chiral ß-lactams, see: J. Chem. Soc., Chem. Commun., 1376 (1988). ... and oligosaccharides as chiral selectors: di- and oligosaccharide chiral selectors in capillary electrophoresis. Chirality. ... for use in the synthesis of chiral ß-lactams. ...
Enantioselective Staudinger Synthesis of β-Lactams Catalyzed by a Planar-Chiral Nucleophile ... A catalytic enantioselective Staudinger reaction is described that preferentially furnishes trans β-lactams. The use of an N- ... Catalytic Asymmetric Staudinger Reactions to Form β-Lactams: An Unanticipated Dependence of Diastereoselectivity on the Choice ...
Enantioselective Conjugate Addition of Organometallic Reagents to Cycloalkenones by the Aid of Chiral Lactam-Phosphine Ligand ( ...
Enantioselective Fluorination of tert-Butoxycarbonyl Lactones and Lactams Catalyzed by Chiral Pd(II)-Bisphosphine Complexes. J ...
Design, synthesis, biological evaluation and cocrystal structures with tubulin of chiral β-lactam bridged combretastatin A-4 ...
... β-unsaturated lactam. The receptors combine a double H-bond donor pattern that resembles the oxyanion hole in natural enzymes, ... Synthesis of a chiral artificial receptor. with catalytic activity. in Michael additions. and its chiral resolution by a new ... Synthesis of a chiral artificial receptor with catalytic activity in Michael additions and its chiral resolution by a new ... lactam. . The receptors combine a double H. -bond donor pattern that resembles the oxyanion. hole in natural enzymes, with a ...
... were obtained for the formation of chiral γ-amino carboxylic acid derivatives and γ-lactams. ... A chiral nickel DBFOX complex as a bifunctional catalyst for visible-light-promoted asymmetric photoredox reactions† ... A chiral nickel DBFOX complex as a bifunctional catalyst for visible-light-promoted asymmetric photoredox reactions X. Shen, Y ... The non-precious chiral catalyst is involved in the photochemical process to initiate single electron transfer and at the same ...
The other two chiral centers can be found in the chiral sulfoxide, a moiety that differentiates sulopenem from other β-lactam ... Those two chiral centers make the synthesis of the chiral sulfoxide costly. Oxalic acid derivatives make up the rest of the ... The chiral base wasnt commercially available in the large amounts they needed. Also, methyl iodide proved to be a fairly ... The next step, N-acylation of the β-lactam nitrogen with an oxalic acid derivative, had to be carried out at -50 °C. "Typical ...
Reactions of chiral beta-lactam-derived epsilon-amino-allylic anions with aldehydes. An application in stereo-divergent ...
... homopropargyl amides provides ready access to synthetically useful chiral γ-lactams with excellent ee by combining the chiral ... Synthesis of γ-lactams. Recent Literature. An oxidative copper-catalyzed arylation of various ring-size lactams with ... γ-lactams using an α-amino-acid-based chiral ligand. This reaction proceeds with excellent efficiency and with outstanding ... This convenient reaction offers a step-economic route to γ-lactams.. S. Huh, S. Y. Hong, S. Chang, Org. Lett., 2019, 21, 2808- ...
Biocatalytic production of bicyclic β-lactams with three contiguous chiral centres using engineered crotonases ... Beta-lactam-synthesizing enzymes carbapenam synthetase (CPS) and beta-lactam synthetase (beta-LS) are evolutionarily linked to ... Naturally occurring β-lactam compounds fall into four basic structural groups, the penicillins/cephalosporins, the clavams, the ... Carbapenam synthetase (CarA) is an ATP/Mg2+-dependent enzyme that catalyzes formation of the β-lactam ring in (5R)-carbapenem-3 ...
  • Here the authors achieve excellent stereocontrol in the synthesis of chiral allenes with a palladium-DTBM-SEGPHOS catalytic system in a non-substrate-dependent manner. (nature.com)
  • This stereoselective radical reaction was used for synthesis of chiral pyroglutamic acid derivatives starting from a commercially available chiral amino acid. (beilstein-journals.org)
  • Substituted γ-lactams, in particular, have potential application in drug synthesis, but the development of stereoselective synthesis of chiral γ-lactams remains a challenge [4,5] . (beilstein-journals.org)
  • Therefore, we were interested in whether our reaction conditions would be suitable for γ-alkyl substrates and would allow the efficient synthesis of chiral N -containing compounds. (beilstein-journals.org)
  • Here, we report cis - and trans -stereoselective radical additions to α-methylene-γ-alkyl- γ-lactams and the synthesis of chiral pyroglutamic acid derivatives using our reaction, starting from a commercially available chiral amino acid. (beilstein-journals.org)
  • Can undergo aldol-type reactions with aldehydes with either syn- or anti-selectivity according to the conditions, for use in the synthesis of chiral ß-lactams. (alfa.com)
  • Synthesis of chiral b2,2,3-3-amino-2-hydroxyalkanoates and 3-alkyl-3-hydroxy-b-lactams by double asymmetric induction. (cnr.it)
  • 1. Yongjie Shi, Xuefeng Tan, Shuang Gao, Yao Zhang, Jingxin Wang, Xumu Zhang, and Qin Yin*, Direct Synthesis of Chiral NH Lactams via Ru-Catalyzed Asymmetric Reductive Amination/Cyclization Cascade of Keto Acids/Esters, Org. (sustech.edu.cn)
  • Design and Synthesis of Chiral oxa-Spirocyclic Ligands for Ir-Catalyzed Direct Asymmetric Reduction of Bringmann's Lactones with Molecular H2. (sustech.edu.cn)
  • Highly Enantioselective Synthesis of Chiral γ-Lactams by Rh-Catalyzed Asymmetric Hydrogenation. (sustech.edu.cn)
  • Asymmetric Synthesis of Chiral Primary Amines by Ruthenium-Catalyzed Direct Reductive Amination of Alkyl Aryl Ketones with Ammonium Salts and Molecular H2. (sustech.edu.cn)
  • γ-Lactams exist in many natural products and biologically active compounds and are one of the most important classes of compounds for drug discovery [1-3] . (beilstein-journals.org)
  • Differentiation of Chiral Compounds Using NMR Spectroscopy. (researchandmarkets.com)
  • Differentiation of Chiral Compounds Using NMR Spectroscopy offers a thoroughly revised second edition to the essential volume that puts the focus on the chiral systems that are commercially available and have been widely vetted for use in NMR spectroscopy. (researchandmarkets.com)
  • Comprehensive in scope, the text describes the chiral NMR differentiating agents as derivatizing agents, solvating agents, metal-based reagents and liquid crystals and gels, and explains the range and types of compounds for which they can be used for analysis. (researchandmarkets.com)
  • Differentiation of Chiral Compounds Using NMR Spectroscopy is a comprehensive guide designed for investigators planning to use NMR spectroscopy to determine enantiomeric purity or assign the absolute configuration of a compound. (researchandmarkets.com)
  • Since these compounds cannot be obtained enantiomerically pure from natural sources, chiral resolution was necessary to study their enantioselectivity. (rsc.org)
  • Oxidation of these compounds using a modification of Tamao's191 procedure gave the potentially useful C-4 hydroxymethyl beta-lactams in good to moderate yield. (bl.uk)
  • The work presented in this thesis is aimed to design efficient reactive crystallization operations that could potentially be implemented in the manufacture of enantiomerically pure compounds and β-lactam antibiotics. (gatech.edu)
  • In addition, the potential of penicillin G acylase goes beyond the biocatalysis of β-lactams due to its enantioselectivity and promiscuity as it can be used for the preparation of chiral and achiral compounds which are convenient in production of active pharmaceutical ingredients and synthons respectively. (transparencymarketresearch.com)
  • On the other hand, penicillin G acylase can also be used in some other useful biotransformation, such as synthesis of peptides and the resolution of racemic mixtures of chiral compounds. (transparencymarketresearch.com)
  • Part I is devoted to general topics related to TLC in the context of drug analysis, including the chemical basis of TLC, sample pleparation, the optimization of layers and mobile phases, detection and quantification, analysis of ionic compounds, and separation and analysis of chiral substances. (routledge.com)
  • Asymmetric Synthesis of Atropisomeric Compounds with an N-C Chiral Axis(2014/01 Org. (shibaura-it.ac.jp)
  • Here, the authors report the atroposelective synthesis of axially chiral arylpyrrole derivatives, which proved to be efficient chiral ligands for asymmetric catalysis, through desymmetrization and kinetic resolution. (nature.com)
  • A stereoselective addition to a γ-lactam skeleton provides a direct and efficient method for synthesizing various γ-lactam derivatives. (beilstein-journals.org)
  • A N -heterocyclic carbene catalyzed formal [3 + 2] annulation of enals with 2-aminoacrylates provides various γ-lactam derivatives in good yields with excellent diastereo- and enantioselectivities. (organic-chemistry.org)
  • Xanthone derivatives were tested as organocatalysts for the Michael addition of pyrrolidine to an α,β-unsaturated lactam . (rsc.org)
  • These products can be converted readily into bioactive δ-lactams, piperidines, and their derivatives. (wiley.com)
  • The enamine-based stereoselective Michael addition of lactols or cyclic hemiaminals to electron-deficient olefinic oxindole motifs provided chiral C4 components, which were further combined with triethylamine catalyzed Michael/Henry sequential reactions affording spirocyclic oxindole derivatives containing six continuous stereogenic centers with excellent enantioselectivities as a single diastereoisomer. (mdpi.com)
  • Synthesis and applications of sulfur-containing chiral ferrocene derivatives, particularly, ferrocene-containing β-lactams: 07SL360. (jeonjucj.kr)
  • Catalytic Asymmetyric Desymmetrization of meso-Diamide derivatives through Enantioselective N-Allylation Using Chiral -Allyl Pd Catalyst: Improvement and Reversal of the Enantioselectivity. (shibaura-it.ac.jp)
  • In summary, C and ECg enhanced the antibacterial effect of β-lactam antibiotics against MRSA in vitro and in vivo , which might be related to the increased accumulation of antibiotics within MRSA via suppression of important efflux pumps' gene expression. (mdpi.com)
  • In fact, MRSA bacteria are resistant to nearly all types of antibiotics, especially β-lactam antibiotics [ 2 ]. (mdpi.com)
  • The main resistance mechanisms of MRSA to the β-lactam antibiotics are a large expression of β-lactamase to destroy β-lactams by hydrolysis, an acquisition of the mecA gene to encode the penicillin-binding protein 2a (PBP2a) with low affinity to β-lactam antibiotics [ 3 ], and an expression of efflux pumps to extrude antibiotics or other toxic agents from the pathogen [ 4 ]. (mdpi.com)
  • Lactam Antibiotics). (abnewswire.com)
  • The second example is a reactive crystallization towards the manufacture of β-lactam antibiotics. (gatech.edu)
  • One of the major drawbacks of the utilization of enzymes towards the manufacture of β-lactam antibiotics is the fact that the same enzyme that catalyzes the synthesis of the antibiotic also catalyzes its hydrolysis and thus, its degradation. (gatech.edu)
  • Owing to the fact that β-lactams comprise 65% of the world antibiotic market and represent the most important group of antibiotics which explains such a tremendous and continuous interest in this enzyme over the decades. (transparencymarketresearch.com)
  • Penicillin G acylase market is also growing with the growing interest of β-lactam antibiotics in the market. (transparencymarketresearch.com)
  • 6-aminopenicillanic acid and 7-Amino-3-methyl-3-cephem-4-carboxylic acid are key intermediates in the production of semisynthetic β-lactam antibiotics. (transparencymarketresearch.com)
  • Penicillin G acylase has gained its demand in the antibiotic industry, where it is used in the production of β-lactam antibiotics. (transparencymarketresearch.com)
  • The increasing drug resistance has fuelled the market for semisynthetic antibiotics, where penicillin G acylase is used to generate intermediates which are helpful in the production of β-lactams. (transparencymarketresearch.com)
  • In order to counter the pathogenicity, pharmaceutical industries are focusing to generate semi-synthetic or modified antibodies, where penicillin G acylase has gained significant importance to generate β-lactam antibiotics. (transparencymarketresearch.com)
  • The mechanism of ß-lactam formation is central to the question of how penicillin and related antibiotics are formed. (jhu.edu)
  • The former problem is centered on the discovery relatively recently of a previously unrecognized mechanism of bacterial cell wall cross-linking analogous to the step inhibited by penicillin and other b-lactam antibiotics but carried out by a family of evolutionarily and structurally distinct enzymes. (jhu.edu)
  • interestingly, changing the identity of the copper ligand changes the product ratio of β/γ-lactams. (rsc.org)
  • A highly enantioselective Ir(III)-catalyzed intramolecular C(sp 3 )-H amidation reaction of dioxazolone substrates provides optically enriched γ-lactams using an α-amino-acid-based chiral ligand. (organic-chemistry.org)
  • Significant advances have been made in the mechanistic understanding of boronate activation via ligand exchange with chiral diols. (bu.edu)
  • Herein we present anthracene-photodimer-derived chiral monophosphine ligand 1, which features dual chirality and a rigid scaffold. (bvsalud.org)
  • The copper catalysed reactions compare favorably in terms of efficiency and enantioselectivity to the corresponding reactions catalysed by commercially available chiral rhodium catalysts. (rsc.org)
  • The direct intermolecular regiospecific and highly enantioselective a-allylic alkylation of linear aldehydes by combination of achiral bench stable Pd(0) complexes and simple chiral amines as co-catalysts is disclosed. (diva-portal.org)
  • The reactions will be rendered asymmetric through the development of asymmetric catalysts and chiral boronate reagents and the utility of the methods developed demonstrated by the asymmetric synthesis of pharmaceuticals and natural products. (bu.edu)
  • Our continued interest in reaction discovery has led to the identification of chiral diol acid catalysts capable of promoting the enantioselective addition reactions to acetals. (bu.edu)
  • Reactions of chiral beta-lactam-derived epsilon-amino-allylic anions with aldehydes. (fnp.org.pl)
  • Evaluation of the elimination reactions performed with lactam 4 . (hindawi.com)
  • Our goal is to examine the use of chiral phosphonamides and phosphonates in stereoselective reactions. (umsl.edu)
  • Whole cells presenting immobilized TliA were shown to catalyze three representative lipase reactions: hydrolysis of olive oil, synthesis of triacylglycerol and chiral resolution. (biomedcentral.com)
  • The development of chiral ligands with privileged scaffolds plays an important role in transition-metal-catalyzed asymmetric reactions. (bvsalud.org)
  • Thus an optically active compound having plural chiral centers.Further, an optically active 2,5,6-substituted-1,3-dioxan-4-one obtained by transesterification and recrystallization is reacted with an alcohol to produce an optically active 2-substituted-3-hydroxycarboxylic acid ester. (patentgenius.com)
  • The present invention relates to an optically active compound having plural chiral centers and processes for producing said compound. (patentgenius.com)
  • One-pot organocatalytic multicomponent reaction, which could meet the demands of atom economy and efficiency, has proven to be a promising approach for the preparation of chiral organic molecules with multistereogenic centers [ 1 , 2 , 3 , 4 , 5 ]. (mdpi.com)
  • The first synthesis of N,O-protected ß2,2,3,3-isoserines bearing two adjacent quaternary stereogenic centers and their corresponding ß-lactams. (cnr.it)
  • This step is highlighted by the xvi simultaneous creation of two stereogenic centers of the γ-lactam core. (usf.edu)
  • More particularly, the new β-lactams are prepared from readily available and enantiomerically pure chiral auxiliaries. (patentsencyclopedia.com)
  • An oxidative copper-catalyzed arylation of various ring-size lactams with arylboronic acids gives N-arylated products in good yield without any additional bases, ligands, or additives. (organic-chemistry.org)
  • The organic synthesis is an illustration of asymmetric synthesis via a chiral auxiliary. (wikipedia.org)
  • In order to ensure the correct stereochemistry (the phenyl group and the silyl ether must adopt a cis configuration) in the β-lactam a chiral auxiliary is used in the enolate synthesis. (wikipedia.org)
  • The acid chloride reacts with the chiral auxiliary trans-2-phenyl-1-cyclohexanol. (wikipedia.org)
  • Both imine and enole intermediate join in a cycloaddition reaction followed by an intramolecular nucleophilic acyl substitution of the amine with expulsion of the chiral auxiliary to the cis-lactam. (wikipedia.org)
  • The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. (elsevier.com)
  • Natarajan, A, Mague, JT & Ramamurthy, V 2005, ' Asymmetric induction during Yang cyclization of α-oxoamides: The power of a covalently linked chiral auxiliary is enhanced in the crystalline state ', Journal of the American Chemical Society , vol. 127, no. 10, pp. 3568-3576. (elsevier.com)
  • Finally, the chiral auxiliary is cleaved and protecting groups are removed to provide the desired taxane. (patentsencyclopedia.com)
  • Chiral ketene enolate formation via nucleophilic activation by the cinchona alkaloid facilitates enantioselective and diastereoselective β-lactam synthesis. (wikipedia.org)
  • γ-Amino-β-hydroxy amide products derived from a diastereoselective addition to N -diphenylphosphinyl imines can be efficiently converted to γ-lactams. (organic-chemistry.org)
  • The synthesis of C-4-alkylated pyrrolidin-3-one 5 was achieved by regio- and diastereoselective alkylation of chiral hydrazone 8 with electrophile 7 followed by selective deprotection. (nationallizenzen.de)
  • 3-Carene, an efficient chiral pool for the diastereoselective synthesis of b-lactams. (iisc.ernet.in)
  • Catalytic Enantioselective Synthesis of Atropisomeric Indoles with an N-C Chiral Axis. (shibaura-it.ac.jp)
  • Catalytic Enantioselective Synthesis of Key Intermediates for NET Inhibitors using Atropisomeric Lactam Chemistry(2008/02 Tetrahedron Lett. (shibaura-it.ac.jp)
  • 102. "Preparation of Chiral Photosensitive Organocatalysts and Their Application for the Enantioselective Synthesis of 1,2-Diamines" Lyu, J. (cnrs.fr)
  • Achiral ketenes and imines, in the presence of a chiral nucleophilic catalyst, are allowed to react to make β-lactams in high yields, enantioselectivities, and diastereoselectivities. (wikipedia.org)
  • We reported the first example of a lathanide chiral catalyst in the addition of simple phosphites to achiral aldehydes. (umsl.edu)
  • This work not only provides strategic guidance for the syntheses of chiral silver nanoclusters in an all-achiral environment, but also deciphers the origin of chirality at molecular level by identifying the special effects of intra- and inter-cluster supramolecular interactions. (bvsalud.org)
  • However, the most commonly used methods for synthesizing chiral γ-lactams are based on the cyclization or cycloaddition of N -containing precursors, which are synthesized stereoselectively, and there are limited studies on the stereoselective additions to γ-lactam skeletons [6-8] and no reports on radical addition. (beilstein-journals.org)
  • Upon Ir catalysis, N -benzoyloxyamides serve as efficient acylnitrenoid precursors to afford γ-lactams. (organic-chemistry.org)
  • In order to study the applicability of this method to C-4 silylmethyl beta-lactams simple N-protected precursors were prepared. (bl.uk)
  • Over the past few years, the combination of dual catalytic systems into asymmetric one-pot tandem procedures has been paid much attention due to the fact that this could provide effective access to valuable chiral complex structures from simple precursors via sequential processes. (mdpi.com)
  • Loughborough University Institutional Repository: Routes to chiral N-acyliminium ion precursors for the synthesis of optically active pure ring-fused pyrroloisoquinoline alkaloids. (lboro.ac.uk)
  • NEW METHODS FOR THE PREPARATION OF TAXANES USING CHIRAL AUXILIARIES - A stereoselective synthesis of novel β-lactam dimers as useful precursors for the preparation of paclitaxel, docetaxel, and analogues thereof. (patentsencyclopedia.com)
  • Enantioselective Fluorination of tert-Butoxycarbonyl Lactones and Lactams Catalyzed by Chiral Pd(II)-Bisphosphine Complexes. (alfa.com)
  • Ir catalysis achieves a lactam synthesis directly from lactones and amines via aminolysis of lactone, N -alkylation of amine with hydroxyamide, and intramolecular transamidation of aminoamide. (organic-chemistry.org)
  • Lactams [ 9 , 10 ] and lactones [ 11 ] are well known anti-bacterial agents. (biomedcentral.com)
  • The newly developed chemistry of the hydroxy phosphonates is being applied toward the synthesis of the cathepsin B, cruzain, and renin inhibitors, lactones and lactams. (umsl.edu)
  • 2008. Structure-directed reversion in the pi-facial stereoselective alkylation of chiral bicyclic lactams . (ub.edu)
  • Bond constructions are selected to access chiral synthetic intermediates that could be used in the construction of pharmaceuticals and natural products. (bu.edu)
  • This compound existed as a mixture of two enantiomers (racemic) and chiral resolution using (−)-alpha-phenylethylisocyanate was employed for the isolation of the (+)-enantiomer. (wikipedia.org)
  • This can take place through the development of the chiral switch enantiomers with suitable bioactivity. (abnewswire.com)
  • A comparative MM-PB(GB)SA binding free energy of solvation values of PCU-lactam and lactone models and their enantiomers as well as the PCU-lactam-NH-EAIS and lactone-CO-EAIS peptide inhibitors and their corresponding diastereomers complexed with South African HIV protease (C-SA) was performed. (biomedcentral.com)
  • A conserved tyrosyl-glutamyl catalytic dyad in evolutionarily linked enzymes: carbapenam synthetase and beta-lactam synthetase. (semanticscholar.org)
  • These data demonstrate the promising of Bg ADH3 in practical synthesis of ( R )-CHBE as a valuable chiral synthon. (biomedcentral.com)
  • The cis - and trans -stereoselective radical additions to α-methylene-γ-alkyl- γ-lactams were investigated and the scope and limitation of the reaction were also revealed. (beilstein-journals.org)
  • A catalytic enantioselective Staudinger reaction is described that preferentially furnishes trans β-lactams. (organic-chemistry.org)
  • A quick, efficient, one-pot, BF 3 OEt 2 -mediated reaction of various substituted arenes with azido alkanoic acid chlorides affords substituted N -aryl lactams in good to excellent yields at room temperature. (organic-chemistry.org)
  • An Al(OTf) 3 -catalyzed cascade cyclization and ionic hydrogenation reaction of nitrogen substituted ketoamides enables an efficient and versatile synthesis of N -substituted lactams, pyrrolindinones, piperidones, and structurally related heterocycles in good yields. (organic-chemistry.org)
  • This convenient reaction offers a step-economic route to γ-lactams. (organic-chemistry.org)
  • We were intrigued by reports from Fleming142 and Taddei141 that allylsilanes bearing a chiral centre directly adjacent to the double bond undergo reaction with various electrophiles, including CSI, with remarkably high stereoselectivity. (bl.uk)
  • We recognised that a suitably substituted bicyclic lactam (A) could act as a precursor in an intramolecular N-acyliminium mediated cyclisation reaction in a stereoselective approach to the core of the erythrinane target ring system. (lboro.ac.uk)
  • Goals of the research program include developing a breadth of reactivity, providing access to novel chiral blocks, and new reaction development. (bu.edu)
  • Jialin Qi, Fang Wei, Chen-Ho Tung, and Zhenghu Xu*, Modular Synthesis of alpha-Quaternary Chiral beta-Lactams by a Synergistic Cu/Pd-Catalyzed Multicomponent Reaction. (sdu.edu.cn)
  • Synthesis of optically active N-C axially chiral tetrahydroquinoline and its response to acid-accelerated molecular rotor(2015/07 Chem. (shibaura-it.ac.jp)
  • Almost all successful syntheses of bicyclic beta-lactams involve the early synthesis of the monocyclic azetidin-2-one ring. (bl.uk)
  • Asymmetric catalysis is a type of catalysis in which a chiral catalyst directs the formation of a chiral compound such that formation of one particular stereoisomer is favoured. (nature.com)
  • A gold-catalyzed tandem cycloisomerization/oxidation of homopropargyl amides provides ready access to synthetically useful chiral γ-lactams with excellent ee by combining the chiral tert -butylsulfinimine chemistry and gold catalysis. (organic-chemistry.org)
  • 20:1 dr and 99% ee) in one pot from simple starting materials (allylic alcohols, enals, diamines and amino alcohols) using cascade transformations promoted by chiral amine/BrOnsted or metal/chiral amine/BrOnsted relay catalysis is disclosed. (diva-portal.org)
  • A new mechanism of b-lactam formation has been discovered and yet another previously unappreciated NRPS mode of catalysis appears to be acting in monobactam biosynthesis. (jhu.edu)
  • Abstract CD‐CZE methods were developed for complete stereoisomeric separations of a series of six γ‐lactam analogues, of which some were neutral, or cationic depending on the background electrolyte nature. (chemistryviews.org)
  • The D ring was synthesized starting from chiral (S)-camphor 8 which was converted to oxime 9 (oxidation / hydroxylamine ), then to amide 10 (hydrolysis), lactam 11 (acid-amide condensation), N-nitroso compound 12, diazo compound 13 and to cyclopentene 14 (carbene, methyl group migration). (wikipedia.org)
  • Reductive Amination/Cyclization of Methyl Levulinate with Aspartic Acid: Towards Renewable Polyesters with a Pendant Lactam Unit. (univ-lille1.fr)
  • Publications] 鈴木一郎: 'Conformationally Rigid Acyclic 2,2,6,6-Tetramethyl-3,5-heptanediol as a New Class of Chiral Auxiliaries' J.Am.Chem.Soc.115. (nii.ac.jp)
  • Now, Park and Chang report an iridium-based catalyst system for the production of chiral γ-lactams from an abundant feedstock via an intramolecular asymmetric sp 3 C−H amidation. (nature.com)
  • Y represents a hydroxy group, an amino group or an acylamino group, which comprises subjecting a β-lactam compound represented by the formula: ##STR2## wherein Ar, R 1 and R 2 have the same meanings as defined above, and X represents a hydroxy group, an amino group or an acylamino group, an azido group or a benzyloxy group, to hydrogenolysis in the presence of a catalyst. (google.com)
  • 2. A process according to claim 1 wherein the amount of the catalyst to be used ranges from 0.1 to 100 mole % in terms of the palladium atom, based on the β-lactam compound. (google.com)
  • More particularly, it relates to a process for the preparation of a dipeptide derivative by hydrogenolysis of a lactam compound in the presence of a catalyst. (google.com)
  • trans γ-lactams with up to 82% ee are achieved with the CuCl 2 -bisoxazoline-NaBARF catalyst system. (rsc.org)
  • The tertiary amine contained within the quinuclidine can act as a nucleophile that attacks the most electrophilic carbon of the ketene to promote the formation of β-lactams. (wikipedia.org)
  • The chiral ketene enolate nucleophile attacks electrophilic carbon of the imine group. (wikipedia.org)
  • The stereochemical outcome of this step is directed by the chiral environment of the enolate itself. (usf.edu)
  • Lectka and co-workers developed a catalytic, asymmetric method to synthesize β-lactams. (wikipedia.org)
  • Unlike the Staudinger β-lactam synthesis, the umpolung ketene in the Lectka β-lactam synthesis behaves as the nucleophile rather than the electrophile. (wikipedia.org)
  • Association constants of the chiral dirhodium(II) carboxamidate Rh(2)(5S-MEPY)(4) with Lewis bases including acetonitrile and amides have been determined by UV-vis titration experiments. (mysciencework.com)
  • From equilibrium associations with acetamide, N-methylacetamide, and N,N-dimethylacetamide, as well as equilibrium constants for lactams and acyclic amides, higher values occur when both the amide carbonyl oxygen and N-H are bound to Rh(2)(5S-MEPY)(4). (mysciencework.com)
  • The Ojima lactam is an organic compound of some importance in the commercial production of Taxol. (wikipedia.org)
  • A Ru-catalyzed enantioselective annulation of 1,4,2-dioxazol-5-ones provides γ-lactams in good yield and high ee via intramolecular carbonylnitrene C-H insertion. (organic-chemistry.org)
  • The first key step involves formation of the γ -lactam core via rhodium (II) catalyzed intramolecular C-H insertion of the α-diazo-α-(phenylsulfonyl)acetamide intermediate. (usf.edu)
  • diyl hydrogen phosphate in capillary electrophoresis by using di- and oligosaccharides as chiral selectors: di- and oligosaccharide chiral selectors in capillary electrophoresis. (alfa.com)
  • Long‐end and short‐end modes and concentration variations of chiral selectors. (chemistryviews.org)
  • Of particular interest are the proteins such as ß-lactam synthetase, active in clavulanic acid formation yet entirely distinct from penicillin biosynthesis. (jhu.edu)
  • The methodology for this transformation has been developed and applied to the synthesis of highly functionalized stereogenic γ-lactams from natural α-amino acids. (usf.edu)
  • This will enable us to rationalize the considerable difference between inhibitory concentration (IC 50 ) of PCU-lactam-NH-EAIS and PCU-lactone-CO-EAIS peptides. (biomedcentral.com)
  • With chiral lactams and acyclic acetamides in their R- and S-configurations equilibrium constants with chiral dirhodium carboxamidates are measures of chiral differentiation, and equilibrium constant ratios as high as three have been determined. (mysciencework.com)
  • Subsequent ring closure leads to the formation of the β-lactam and the regeneration of the chiral nucleophilic organocatalyst. (wikipedia.org)
  • For the most promising receptor , this was accomplished using a new methodology that exploits its supramolecular interactions with a chiral guest and that is inspired in dynamic combinatorial chemistry. (rsc.org)
  • Studied chemistry at Simmons College in Boston, and did her dissertation in the field of physical chemistry at Brandeis University on the solution structure of chiral ions pairs by NMR spectroscopy. (bruker.com)
  • X-ray structures and detailed mechanistic enzymology of both enzymes have opened the way to protein engineering and directed evolution experiments to capture the synthetic power and chiral selection of these enzymes to accept alternate substrates and produce other medicinally-useful products. (jhu.edu)
  • Opposite Enantioselectivity in the Bioreduction of ( Z )-β-Aryl-β-cyanoacrylates Mediated by the Trp 116 Mutants of Old Yellow Enzyme 1: Synthetic Approach to ( R )- and ( S )-β-Aryl-γ-lactams. (ufl.edu)
  • In cases where there are competing C-H insertion pathways available, to form sulfolanes or thiopyrans, only the insertion into the amide chain to form γ-lactams is observed. (rsc.org)
  • The adsorption of certain chiral amino acids from aqueous solution onto β-cyclodextrin silica particles (CDS) had been investigated with the aim of in-depth understanding of the host-guest interaction. (scirp.org)
  • Chiral amino acids are one of the most important biomolecules because of their relevance in nature and their chemical richness. (scirp.org)
  • Therefore, chiral analysis of D/L-amino acids is of increasing importance in biological science. (scirp.org)
  • Various chiral separation methods are available for the enantiomeric resolution of amino acids. (scirp.org)
  • In this paper, we report both experimental and theoretical results on adsorption behaviour of certain chiral amino acids on β-CD bonded to silica gel with emphasis on understanding the host-guest interaction and such a study will be useful for better understanding of the chiral recognition mechanism of amino acids by β-CD bonded silica gel as a selective sorbent. (scirp.org)
  • The stereoisomers ( ) 6 , (+) 7 , (+) 6 , and ( ) 7 had molecular formulae C 32 H 39 O 4 N, established by FAB HR MS, indicating the addition of the en antiomerically pure amines (C 8 H 11 N) to rac diligustilide ( 1 ) (C 24 H 28 O 4 ). (scielo.org.mx)
  • The lactam peptide exhibits an order of magnitude better HIV protease inhibitory activity, in comparison with the lactone analogues. (biomedcentral.com)
  • 104. "Chiral Phosphoric Acid-Catalyzed Enantioselective Construction of 2,3-Disubstituted Indolines" Ma, W.-Y. (cnrs.fr)
  • Chiral phosphoric acid based organocatalysis and visible-light photocatalysis have both emerged as promising technologies for the sustainable production of fine chemicals. (cnrs.fr)
  • Toward this goal, several BINOL-based chiral phosphoric acid backbones presenting one or two visible-light-sensitive thioxanthone moieties have been prepared and studied. (cnrs.fr)
  • Their unlimited structural diversity and versatile applications are being used as chiral building blocks and molecular scaffolds in building combinatorial libraries. (abnewswire.com)
  • His areas of study included substituted b lactams, taxoids, and antibacterials. (bruker.com)
  • Axially chiral arylpyrroles are structural motifs often found in natural and medicinal products. (nature.com)
  • Methods based on chiral ligandexchange [7-10] and on the formation of inclusion complexes with cyclodextrins have received the most attention [11-13]. (scirp.org)
  • Ethyl ( R )-4-chloro-3-hydroxybutyrate (( R )-CHBE) is a versatile chiral precursor for many pharmaceuticals. (biomedcentral.com)
  • The pharmaceutical industry accounts for almost 80% of chiral market revenues. (abnewswire.com)
  • Despite the fact that chiral drugs have been in use much before the arrival of modern medicine, it is only now that chiral drugs in the pharmaceutical industry has gained so much attention. (abnewswire.com)
  • It can be argued that these characteristics will ensure better eletronic interaction between the lactam and the receptor, corresponding to the observed HIV protease activities in terms of experimental IC 50 data. (biomedcentral.com)