Reaction of acetal. Medical search. Frequent questions

Another way to avoid the entropic cost is to perform the synthesis by acetal exchange, using a pre-existing acetal-type reagent as the OR'-group donor rather than simple addition of alcohols themselves. (wikipedia.org)
Acetals are used as protecting groups for carbonyl groups in organic synthesis because they are stable with respect to hydrolysis by bases and with respect to many oxidizing and reducing agents. (wikipedia.org)
Acetalisation is often used in organic synthesis to create a protecting group because it is a reversible reaction. (wikipedia.org)
The Kobayashi aldol reaction is one of the most powerful methods to synthesize the polyketide skeleton and has been applied to the total synthesis of natural products. (elsevierpure.com)
The synthesis of isopropyl and isobutyl ethers of the bicyclic alcohol 1 was accomplished using this methodology, although reactions in the synseries were complicated by the formation of tricyclic products by an intramolecular cyclisation. (illinois.edu)
The reaction is based on a mechanism that frequently occurs in nature, but has rarely been used in chemical synthesis up to now. (nanowerk.com)
During acetal synthesis, titanium first absorbs an oxygen atom and then releases it again (oxidation is followed by a so-called reduction). (nanowerk.com)
In Chapter II, a unique strategy for enantioselective synthesis of bicyclic lactam N,S-acetals scaffolds was developed. (miun.se)
Chapter III focuses on a stereodivergent synthesis of fluorinated lactams bearing two vicinal stereogenic centers by multicomponent reaction. (miun.se)
Also, be familiar with the use of acetals and cyclic acetals as protecting groups in synthesis. (utexas.edu)
Stereochemical insights into the biogenesis of polygalolides A and B have been provided by the stereocontrolled total synthesis of these natural products (see scheme), wherein the key steps include a highly diastereoselective hetero-Michael reaction, a [Rh 2 (OAc) 4 ]-catalyzed carbonyl ylide formation/1,3-dipolar cycloaddition, and a Mukaiyama aldol-type reaction. (wiley.com)
The butane di-acetal (BDA) derivatives 293, 300, and 301 (as well as acetylated and methylated derivatives thereof) were prepared during work directed towards the synthesis of the inositol core of a phosphatidylinositol manno-oligosaccharide (PIM-6) isolated from Mycobacterium bovis and M. smegmatis. (vuw.ac.nz)
Also, process development work was done to adapt the preparation so that it was suitable for scale-up, and a subsequent large scale synthesis of the acetal was undertaken. (vuw.ac.nz)
Glavač, D., Jerić, I. & Gredičak, M. (2019) Organocatalytic Synthesis of α,α-Diaryl Substituted α-Amino Acid Derivatives by an Interrupted Three-Component Ugi Reaction . (irb.hr)

It was clearly suggested by (i) the intramolecular cyclization of ketene N,S -acetals 7 to the corresponding thiophenes 8 , (ii) 1 H NMR studies of Meldrum's acid-substituted aminothioacetals 9 , and (iii) substitution studies of the methoxy group on Meldrum's acid containing N,S -acetals 9b . (beilstein-journals.org)
The compound (5S,6S,11aS)-hexahydro-6-methyl-5- phenylspiro[l H,7 H-pyrrolo[2,l-e][l,3,6,2]dioxazasilonine- 3,1'-silacyclopentan]-7-one (1) results from the silicon-directed condensation of the prolinol-derived O-silacyclopentyl ketene N,O-acetal (2) with benzaldehyde. (caltech.edu)
Mechanistic studies of the reaction of the (S)-prolinol-derived O-silyl ketene N,O-acetal 1 with aromatic aldehydes are reported. (caltech.edu)
Experiments with three 0-silyl ketene N,O-acetals derived from different 1,2-amino alcohols are also described and lead to a coherent mechanistic picture involving pseudorotation of trigonal bipyramidal organosilicon intermediates. (caltech.edu)
The strategy includes a stereoselective vinylogous Mukaiyama aldol reaction (VMAR) using chiral silyl ketene N,O-acetal to construct C6-C7 stereocenters, an E-selective ring closing metathesis to construct a C12-C13 olefin, and stereodivergent construction of a C8-C9 epoxide. (unboundmedicine.com)
List, B. The Catalytic Asymmetric Mukaiyama-Michael Reaction of Silyl Ketene Acetals with α,β-Unsaturated Methyl Esters. (mpg.de)

Acetals are formed from and convertible to aldehydes or ketones and have the same oxidation state at the central carbon, but have substantially different chemical stability and reactivity as compared to the analogous carbonyl compounds. (wikipedia.org)
The term ketal is sometimes used to identify structures associated with ketones (both R groups organic fragments rather than hydrogen) rather than aldehydes and, historically, the term acetal was used specifically for the aldehyde-related cases (having at least one hydrogen in place of an R on the central carbon). (wikipedia.org)
The use of bismuth nitrate enables a chemoselective deprotection of acetals derived from ketones and conjugated aldehydes. (organic-chemistry.org)
We will be learning about the nomenclature and reactions of aldehydes and ketones, including how to use acetals as protecting groups. (khanacademy.org)
The mechanism of the reaction with aldehydes or ketones. (utexas.edu)
Utilizing thioxanthenone as the photocatalyst and inexpensive household lamps as the light source, a variety of aromatic and aliphatic aldehydes have been converted into acyclic and cyclic acetals in high yields. (blogspot.com)

In spite of inefficient hydrolysis of 1-(2-aminophenyl)-2,2,3,3,4,4,4-heptafluorobutan-1-one diethyl acetal ( 2 ), this compound undergoes readily the acid-catalyzed Friedländer reaction with enolizable ketones to give the corresponding quinolines ( 4 - 6 ). (heterocycles.jp)
reaction--see text] The butane-2,3-diacetal (BDA) desymmetrized glycolic acid building block undergoes efficient and highly diastereoselective lithium enolate Michael additions to alpha,beta-unsaturated ketones, lactones, and nitro olefins. (unboundmedicine.com)
Matišić, M. & Gredičak, M. (2021) Enantioselective construction of a tetrasubstituted stereocenter in isoindolinones via an organocatalyzed reaction between ketones and 3-hydroxyisoindolinones . (irb.hr)

Recent advances in the study of acetal hydrolysis and the use of acetals in model systems for the investigation of enzymically catalysed hydrolysis are reviewed. (gla.ac.uk)
The kinetics of the hydrolysis of benzaldehyde substituted (X) - phenyl methyl acetals and substituted (Y)-benzaldehyde phenyl methyl acetals were measured in pivalate , acetate, d1-deutero-acetate, beta-chloropropionate, formate and chloroacetate buffers, and in hydrochloric and deutero-chloric acids. (gla.ac.uk)
The hydrolysis rates measured in buffer solutions, of the twelve acetals studied were found to be dependent on the concentration of undissociated acid and shown to be authentic examples of general acid catalysis, with reference to current opinions that such observations might be manifestations of solvent, electrolyte or buffer effects. (gla.ac.uk)
It seemed not unreasonable to assume that the same process occurs also in the hydrolysis reaction. (gla.ac.uk)
The results obtained were all indicative of an A-SE2 mechanism in the general acid catalysed hydrolysis of aromatic aryl methyl acetals, with concerted proton transfer to phenolic oxygen and carbon-phenolic oxygen bond fission in the rate limiting step and where incipient carbonium ion stability and leaving group ability, rather than a high relative degree of proton transfer in the transition state, were commensurate to faster hydrolysis rates. (gla.ac.uk)
of general acid catalysis in acetal hydrolysis, although relief of steric strain through carbonium ion formation is also relevant. (gla.ac.uk)
The hydrolysis of benzaldehyde methyl acetyl acylal, the possible intermediate of acetate anion nucleophilic attack on benzaldehyde phenyl methyl acetal, was found to be general acid catalysed, and is believed to be the first reported example of buffer catalysis in acylal hydrolysis. (gla.ac.uk)
A series of sterically similar five- and six-membered ring cyclic diol-derived ketone acetals have been prepared and their rates of acid-catalysed hydrolysis examined. (worktribe.com)
Cyclic acetals are more stable towards hydrolysis than acyclic ones, they are also much easier to make. (chemtube3d.com)

Cyclic acetals are readily formed by the reaction of two molecules, a ketone and a diol. (chemtube3d.com)

Formation of an acetal occurs when the hydroxyl group of a hemiacetal becomes protonated and is lost as water. (wikipedia.org)
As a reaction to create an acetal proceeds, water must be removed from the reaction mixture, for example, with a Dean-Stark apparatus, lest it hydrolyse the product back to the hemiacetal. (wikipedia.org)
10.Be able to write the detailed mechanism for acid and base catalyzed hemiacetal formation .Also, write the mechanism for the acid catalyzed conversion of a hemiacetal to an acetal. (utexas.edu)

Acetals are stable compared to hemiacetals but their formation is a reversible equilibrium as with esters. (wikipedia.org)
In view of the high compatibility between ozone and ionic liquids, two ozone -mediated model reactions were chosen: firstly the oxidation of acetals to esters in the presence of ozone and secondly the ozonation of methyl oleate to monomethyl azelate and pelargonic acid . (rsc.org)
List, B. Scalable and Highly Diastereo- and Enantioselective Catalytic Diels−Alder Reaction of α,β - Unsaturated Methyl Esters. (mpg.de)

However, in contrast to historical usage, ketals are now a subset of acetals, a term that now encompasses both aldehyde- and ketone-derived structures. (wikipedia.org)
Acetalisation is the organic reaction that involves the formation of an acetal (or ketals). (wikipedia.org)

One way of acetal formation is the nucleophilic addition of an alcohol to a ketone or an aldehyde. (wikipedia.org)
Why are nucleophilic substitution and elimination reactions introduced before electrophilic addition reactions or nucleophilic addition reactions? (teachthemechanism.com)
Why are nucleophilic addition reactions presented in two chapters (Chapters 18 and 19)? (teachthemechanism.com)
Similarly, why are nucleophilic addition-elimination reactions presented in two separate chapters (Chapters 22 and 23)? (teachthemechanism.com)

Key features of this sequence include the coupling of the enol triflate 11 and the arylboronic acid 10 (90%), the thermal deprotection/internal amidation of the coupling product 18 (84%), the use of 2-chloropyridine as an economical alternative to 2,6-di-tert-butylpyridine to promote the reaction of the quinolone 9 and triflic anhydride (85%), the highly stereoselective addition of the (Z)-enediyne 31 to the quinoline 61 (89%), intramolecular acetylide addition within the acetylenic ketone 66 (94%), and oxidation of the phenol 76 with iodosobenzene to afford the quinone imine precursor 77 in 89% yield. (caltech.edu)
A1do1 reactions with the C-8 to C- 11 ketone have been investigated, and subsequent progress towards the assembly of the pyranose ring fragment is presented. (vuw.ac.nz)

The formation of acetals reduces the total number of molecules present (carbonyl + 2 alcohol → acetal + water) and therefore is generally not favourable with regards to entropy. (wikipedia.org)
One situation where it is not entropically unfavourable is when a single diol molecule is used rather than two separate alcohol molecules (carbonyl + diol → acetal + water). (wikipedia.org)
Various specific carbonyl compounds have special names for their acetal forms. (wikipedia.org)

For example, an acetal formed from formaldehyde (two hydrogens attached to the central carbon) is sometimes called a formal or the methylenedioxy group. (wikipedia.org)
Contains formaldehyde cyclododecyl ethyl acetal, delta-1-(2,6,6-trimethyl-3-cyclohexen-1-yl)-2-buten-1-one, may produce an allergic reaction. (esteban.fr)
All of the formaldehyde is produced from an exothermic reaction occurring at atmospheric pressure and 300-400 EC. (cdc.gov)

List, B. Asymmetric Lewis Acid Organocatalysis of the Diels-Alder Reaction by a Silylated C-H Acid. (mpg.de)
Why are the Diels-Alder, syn dihydroxylation, and oxidative cleavage reactions introduced in their own chapter (Chapter 26) instead of alongside electrophilic addition reactions (Chapters 12 and 13)? (teachthemechanism.com)
With the Karty textbook, can I teach alkene/alkyne chemistry in its entirety (including Diels-Alder and oxidative cleavage reactions) in first semester? (teachthemechanism.com)

The arylmethylidene moiety of these natural products was successfully installed by a Mukaiyama aldol-type reaction of a silyl enol ether with a dimethyl acetal, followed by elimination under basic conditions. (wiley.com)
When the C2 hydroxy group was protected as TBS ether, the C1 carboxylic acid did not undergo esterification with a bulky secondary alcohol, while the p-methoxybenzylidene N,O-acetal afforded 2,4-dimethyl-3-pentyl ester. (researchgate.net)

A syn-selective Kobayashi aldol reaction by using the E,E-vinylketene silyl N,O-acetal and an excess amount of Lewis acid is presented. (elsevierpure.com)

However, the reaction of [ 1 ] with the Fe 3 (CO) 12 -pyridine N -oxide (PyNO) reagent system selectively afforded 1,2-diphenylethane derivatives [ 2 ]. (go.jp)

Nanowerk News ) Acetals are important chemical compounds that are used, for example, in the production of certain medical agents. (nanowerk.com)

The mechanism for this reaction is based on the formation of a sulfur ylide-like intermediate. (beilstein-journals.org)
The rates of reaction of products 4 and 5 with GSH are roughly comparable to that of 1, while the calicheamicin-glutathione disulfide 6 forms 3 at a rate approximately 2 orders of magnitude slower than the rate of formation of 3 from 1. (caltech.edu)
Next, the addition of thiol amine leads to the construction of bicyclic lactams via a imine/N,S-acetal formation/lactamization cascade sequence. (miun.se)
The reaction proceeds via enantioselective Michael addition /imine formation/lactamization cascade process. (miun.se)
Be familiar with cyclic acetal formation and the reason it is especially favorable. (utexas.edu)
May be much simple protection procedure is the acetal formation with ethylene glycol or some other CHO protecting group. (chemicalforums.com)
The formation of myo-inositol camphanylidene acetal 269a is one successful solution, and work done in an attempt to better understand the selectivity of the reaction is reported here. (vuw.ac.nz)
The reaction produces two products, the acetal plus water, so the usually unfavourable entropy of acetal formation is not a factor. (chemtube3d.com)
Formation is also kinetically favoured because the intramolecular ring-closing reaction is fast. (chemtube3d.com)
Formation of acetals . (wikidoc.org)

Non-symmetrical acetals have been combined with Grignard reagents in toluene at reflux to generate α-and β-branched ethers in moderate to high yields. (illinois.edu)
The results are published in the journal Angewandte Chemie ( 'Oxidizing under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom-Economy by Titanocene(III)-Catalysis' ). (nanowerk.com)

Goldberg and coworkers first demonstrated that the reaction of the isolated chromophore (1) with thiols in the presence of double-stranded DNA leads to DNA cleavage by a free-radical mechanism. (caltech.edu)
The following detailed mechanism emerges for the DNA cleavage reaction. (caltech.edu)
Write the mechanism of the reaction and explain why this strategy works. (utexas.edu)

Under what conditions are acetals stable? (utexas.edu)

The compound exhibits reactions expected for an electrophilic alkynyl aldehyde. (wikipedia.org)
For example, Shen and co-workers reported the use of trifluoromethyl-substituted sulfonium ylide 5 in electrophilic trifluoromethylation reactions [33,34] . (beilstein-journals.org)

Beriša, A. & Gredičak, M. (2023) Chiral phosphoric acid-catalyzed Friedel-Crafts reaction of 2,5-disubstituted and 2-monosubstituted pyrroles with isoindolinone-derived ketimines . (irb.hr)

Loss of the proton from the attached alcohol gives the acetal. (wikipedia.org)
Why is curved arrow notation for reactions introduced in Chapter 6 in the context of proton transfer reactions? (teachthemechanism.com)
Why are reaction free energy diagrams introduced in Chapter 6 in the context of proton transfer reactions? (teachthemechanism.com)

The halide component of the Grignard reagent and the solvent were found to be an important factor in facilitating these reactions. (illinois.edu)
The success of this methodology relies critically upon the purity of the NBSH reagent employed in the reaction. (caltech.edu)
Samarium(II) iodide (SmI 2 , Kagan's reagent) has been widely used to forge challenging C-C bonds through reductive coupling reactions. (mdpi.com)

Acetals of lactams and acid amides. (chemspider.com)

The catalysis we have developed simply shifts this oxygen in the molecule, which creates the acetal. (nanowerk.com)

This methodology has been used to construct anti-aldol products, and only a few precedents on the syn-selective Kobayashi aldol reaction are known. (elsevierpure.com)
The C-7 to C-8 bond was to be formed via an asymmetric aldol reaction to give the pyranose ring fragment (highlighted in blue). (vuw.ac.nz)

The d1-acetic acid catalysed d4-methanolysis of benz-aldehyde phenyl methyl acetal was followed in a high resolution N. M. R. spectrometer and the initial bond fission found to occur between carbon and the phenolic oxygen. (gla.ac.uk)

The reaction of 2 with pentanal yields quinoline ( 12 ) as the major product. (heterocycles.jp)

The experimental evidence suggests that the cumulene intermediate undergoes cycloaromatization while bound to DNA and that the biradical formed in this cycloaromatization reaction is a highly reactive and poorly selective intermediate. (caltech.edu)
In the presence of Lewis acids, 2,3-homotropone 1 smoothly undergoes cycloaddition reactions with cyclopentadiene and butadiene in [4π+2π] fashion with "inverse electron demand," the dienes acting as dienophiles. (go.jp)

Used in a more general sense, the term X,Y-acetal also refers to any functional group that consists of a carbon bearing two heteroatoms X and Y. For example, N,O-acetal refers to compounds of type R1R2C(OR)(NR'2) (R,R' ≠ H) also known as a hemiaminal ether) and S,S-acetal refers to compounds of type R1R2C(SR)(SR') (R,R' ≠ H, also known as a thioacetal). (wikipedia.org)

In this work we tackle the problematic separation of reaction products from ionic liquid media. (rsc.org)
The objective was to retain the ionic liquid phase by means of a solvent-resistant nanofiltration membrane , while the organic reaction products permeate through the polymeric membrane . (rsc.org)

The key step in the production of acetals is the bonding of two oxygen atoms to one carbon atom. (nanowerk.com)
Strong oxidizing agents are normally used to accomplish this by releasing an oxygen atom during the reaction. (nanowerk.com)

And that makes sense, guys, because remember that this is a reversible reaction. (pearson.com)

Highly diastereoselective Michael addition reactions of butane-2,3-diacetal desymmetrized glycolic acid. (unboundmedicine.com)

The mild reaction conditions (neutral pH, reaction temperatures ≤23 °C) are especially attractive for substrates containing sensitive functional groups. (caltech.edu)
According to the afatinib refined product synthetic method, the reaction process condition is mild, the corrosion risk to reaction equipment is lowered, the reaction process is simplified, operation is easy, the purity of the product is high, and the yield is increased conveniently. (lookchem.com)

The scope and limitations of the ether-forming reactions were explored with a series of acetals derived from primary, secondary and tertiary alcohols. (illinois.edu)

Why are radical reactions presented at the end of the book (Chapter 27)? (teachthemechanism.com)

Acetic acid is one of the most important bulk commodity chemicals and is currently manufactured by methanol carbonylation reactions with rhodium or iridium organometallic complexes and halide-containing promoters named Monsanto or BP Cativa™ homogeneous processes, respectively. (blogspot.com)
Why are the reactions that form organometallic reagents presented in Chapter 20? (teachthemechanism.com)

New and existing data pertaining to the potential role of DNA as a catalyst in the thiol activation reaction and to the potential participation of the carbohydrate amino group of 1 in that reaction is evaluated. (caltech.edu)
This enabled the researchers in their study to optimize their catalyst so that it completely converts the starting material into the desired acetal. (nanowerk.com)
The first uses silver as a metal catalyst in its reactions. (cdc.gov)
The simultaneous reactions involved in the metal catalyst process occur at essentially atmospheric pressure and 600-650 EC (Gerberich et al. (cdc.gov)

Resonance appears in Chapter 1 to give students as much practice with predicting molecular stability and drawing curved arrows as possible before they are held accountable for working with reactions and mechanisms. (teachthemechanism.com)

What is the only product obtainable in good yield in such a reaction? (utexas.edu)

The reaction solvent used in the lactamizarion step gives switchable diastereoselectivity to the fluorinated quaternary stereocenter. (miun.se)

In this case, water produced along with the acetal product is destroyed when it hydrolyses residual orthoester molecules, and this side reaction also produces more alcohol to be used in the main reaction. (wikipedia.org)
The reaction of the chromophore subunit (1) of the natural antitumor antibiotic neocarzinostatin with methyl thioglycolate produces an NMR-observable intermediate, assigned as 2, which decays with a half-life of ~2 h at -38 °C to form the putative biradical 3. (caltech.edu)

Although conventional acrylic resins (polymethyl methacrylate-PMMA) offer appropriate esthetics, they do not meet all the mechanical requirements imposed on removable partial dentures 6 since PMMA is subject to mechanical failures and dimensional changes, and may cause allergic reactions 7 . (bvsalud.org)

Asymmetric organocatalysis, cooperative dual catalysis and one-pot multicomponent reaction strategies were applied for the construction of continuous and quaternary stereogenic center. (miun.se)
Since such a reaction introduces an additional stereogenic center, two anomers are formed (α-isomer and β-isomer) from each distinct straight-chain monosaccharide. (wikidoc.org)

3. Skip the haloform reaction and the iodoform test. (utexas.edu)
Can I skip Chapter 7 (An Overview of the Most Common Elementary Steps), because the topics will be revisited later in the book in the context of the reactions where they apply? (teachthemechanism.com)

The title compound, (4S,5S,8R,10Z)-2,2,5,6,8,10- hexamethyl-4-phenyl-l,3-dioxa-6-aza-2-silacycloundec- 10-en-7-one, crystallizes with two virtually identical molecules in the asymmetric unit, each with the same absolute configuration. (caltech.edu)

acetals do not form under basic conditions. (wikipedia.org)

Why are multistep mechanisms introduced in the context of S N 1 and E1 reactions in Chapter 8? (teachthemechanism.com)

Practicing with resonance helps students understand and make predictions about key aspects of molecular stability, a major factor that dictates the outcome of a chemical reaction. (teachthemechanism.com)

Another possible pathway is through the reaction of propynylidyne (C3H) with water. (wikipedia.org)
A New and Unusual Pathway for the Reaction of Neocarzinostatin Chromophore with Thiols. (caltech.edu)

Similarly, the negative p values obtained from the substituted (X) - benzaldehyde acetals increased in magnitude from. (gla.ac.uk)

In 1992, Saito and co-workers showed that the reaction of holo-NCS with small thiols, such as β-mercaptoethanol (BME), takes a different course, to form a product that is formally a 1:1:1 adduct of thiol, 1, and water. (caltech.edu)
The calicheamicin-glutathione disulfide 6 is formed as the major product of the reaction, while the dihydrothiophene derivative 3, the thiosulfenic acid derivative 4, and the calicheamicin-glutathione trisulfide 5 are formed as comparatively minor products. (caltech.edu)
The reaction of p-substituted benzyl chlorides [ 1 ] with Fe 3 (CO) 12 in benzene gave p-substituted diphenylmethanes [ 3 ] as a major product. (go.jp)

Chemicals and Drugs4

Phenomena and Processes3

Disciplines and Occupations1

Synthesis14

Ketene6

Aldehydes6

Ketones3

Hydrolysis9

Cyclic acetals1

Hemiacetal3

Esters3

Ketals2

Nucleophilic addition4

Ketone2

Carbonyl3

Formaldehyde3

Diels-Alder3

Dimethyl2

Silyl1

Derivatives1

Chemical Compounds1

Formation10

Ethers2

Mechanism3

Stable1

Electrophilic2

Chiral1

Proton3

Reagent3

Lactams1

Molecule1

Aldol2

Aldehyde1

Yields1

Undergoes2

Compounds1

Ionic liquid2

Oxygen2

Reversible reaction1

Diastereoselective1

Mild2

Alcohols1

Radical Reactions1

Organometallic2

Catalyst4

Arrows1

Yield1

Solvent1

Produces2

Allergic1

Stereogenic2

Skip2

Asymmetric1

Conditions1

Mechanisms1

Resonance1

Pathway2

Similarly1

Product3