1453-21-0Relevant articles and documents
Synthesis of Formaldehyde Acetals by Phase Transfer Catalysis
Wang, Maw-Ling,Chang, Shahng-Wern
, p. 2149 - 2155 (1993)
By employing phase transfer catalysis, formaldehyde acetals were synthesized from the reaction of alcohols and dibromomethane at moderate temperatures.Using a high alkaline concentration, the reaction could be improved to obtain a 100percent yield by reacting dibromomethane and 1-alcohol employing tetrabutylammonium bromide (TBAB) as a phase transfer catalyst.Six kinds of alcohols with various structures, four sorts of solvents with various dielectric constants and seven types of catalysts were examined to test their reactivities to the reactions.Only one unique product with two alkoxides substituents was observed which indicated the presence of a rather fast reaction rate during the second reaction of the organic phase.The reaction was dramatically enhanced by adding a small amount of quaternary ammonium salt (QX) to obtain a 100percent yield utilizing the alcohols with nonbonding electron pairs within a short period of reaction time.The conversion was also observed to be strongly dependent upon the structure of the quaternary ammonium salts.The reaction rate and the product yield were satisfactorily accounted for the chemical reaction equilibrium of alcohols and KOH in the aqueous phase, the hydration of the active catalyst (QOR) in the organic phase and the distribution of QOR between two phases.
Dimethyl sulfoxide as a "methylene" source: Ru(ii) photo-catalysed facile synthesis of acetals from alcohols
Talukdar, Ranadeep
supporting information, p. 13334 - 13338 (2019/09/06)
Acetals are important molecules with versatile reactivity and uses. For the first time a simple photo-catalysed facile synthesis of formaldehyde acetals is documented herein upon the reaction of alcohols with dimethyl sulfoxide under very mild conditions in the presence of air. The reactions require only 1 mol% of RuII(bpy)3Cl2 photocatalyst under blue LED irradiation (λ = 445 nm) to give good to excellent yields of the corresponding acetal products. Here DMSO acts as a "methylene" source.
A new and more efficient synthesis of methylene acetals
Chu, Guobiao,Zhang, Yanqiao,Li, Chunbao,Zhang, Yuqing
experimental part, p. 3828 - 3832 (2010/03/03)
A new and efficient synthesis of benzyl chlorides and methylene acetals by use of 2,4-dichloro-6-methoxy[l,3,5]triazine (MeOTCT) and dimethyl sulfoxide has been developed. Chlorides are the major products for benzyl alcohols, while methylene acetals are the major products for secondary alcohols. This procedure provides the highest yields so far for methylene acetals of steroids. A plausible mechanism is proposed on the basis of the experiments. Georg Thieme Verlag Stuttgart.
Simple synthesis of N-alkoxymethyl derivatives of anilides
Danikiewicz,Szmigielski
, p. 3047 - 3054 (2007/10/03)
Facile, two-step synthesis of N-alkoxymethyl derivatives of anilides consisting of the methoxymethylation of the appropriate anilides with chlomethyl methyl ether followed by heating with an alcohol in the presence of an acid is described.
Methylene acetals as protecting group - An improved preparation method
Guiso, Marcella,Procaccio, Carmela,Fizzano, Maria Rosaria,Piccioni, Francesco
, p. 4291 - 4294 (2007/10/03)
A facile method to protect vic diols, 1,3 diols and other hydroxyl functions as methylene acetals is achieved by treating the relative substrates with POCl3 or SOCl2 in DMSO. The good yields obtained, the good solubility of many orga
Montmorillonite, an efficient catalyst for the preparation of dialkoxymethanes
Deshmukh,Gumaste,Bhawal
, p. 3939 - 3944 (2007/10/03)
The reaction of various alcohols with paraformaldehyde in presence of montmorillonite to give dialkoxymethanes (2a-g) in very good yield is described.
Approaches to Chemically Modified Enzymes As Synthetic Catalysts
Aitken, David J.,Alijah, Renate,Onyiriuka, Samuel O.,Suckling, Colin J.,Wood, Hamish C. S.,Zhu, Limin
, p. 597 - 608 (2007/10/02)
Attempts to introduce new catalytic activities of potential use in synthetic transformations into enzyme active sites are described.Substitution of the naturally occurring zinc in carboxypeptidase A by several metals known to catalyse hydrogenation was investigated; a new protein characterised as a rhodium carboxypeptidase was isolated but it failed to show activity as a hydrogenation catalyst for the reduction of a series of dehydroamino acid amides.Horse liver alcohol dehydrogenase was investigated for its potential to act as an oxygen transferase via Lewis acid catalysis.A series of cyclohexenyl and phenylribosides together with new alkenyl(arenyl)oxymethylenoxyethanols was prepared for evaluation as substrates; in the course of this study, novel neighbouring group participation by the oxygen atom of a chloromethyl ether was observed.Although the binding of potential oxygen acceptors (alkenes and aromatic compounds) and oxygen donors (hydrogen peroxide and alkyl hydroperoxides) was demonstrated, oxygen transfer did not occur with the combinations investigated.In contrast to the failure of the above metalloenzymes to catalyse new reactions, papain modified at the active site sulfhydryl group by thiazolium salts and pyridinium salts was shown to exhibit reactions characteristic of the covalently attached cofactor.Thus the thiazolopapains acted as decarboxylation catalysts for pyruvate and the pyridinopapains could be reduced to dihydropyridines which reduced electrophilic carbonyl substrates with small enantiomeric excess.
NOVEL REACTIVITY OF 2-(CHLOROMETHOXY)ETHYL ACETATE
Aitken, David J.,Rees, Lilias,Suckling, Colin J.,Wood, Hamish C. S.
, p. 3417 - 3420 (2007/10/02)
2-(Chloromethoxy)ethyl acetate reacts with alcohols in the presence of silver carbonate to produce 2-(alkoxymethoxy)ethyl acetates and bis(alkoxy)methanes.A mechanism which involves neighboring group participation of a chloromethyl ether oxygen atom is proposed to account for the formation of the latter products.
