19752-94-4Relevant academic research and scientific papers
Reactions in Slightly Hydrated Solid/Liquid Heterogeneous Media: The Methylation Reaction with Dimethyl Sulfoxide
Achet, D.,Rocrelle, D.,Murengezi, I.,Delmas, M.,Gaset, A.
, p. 642 - 643 (1986)
The O-methylation of alcohols and phenols with stoichiometric amounts of dimethyl sulfate in 1,4-dioxan or triglyme in the presence of solid potassium hydroxide and small amounts of water represents a useful method for the synthesis of methyl ethers in high yields and with high selectivity.The complete consumption of dimethyl sulfate in this reaction avoids the problems connected with the work-up of reaction mixtures still containing excess amounts of this toxic reagent.
Auto-Tandem Catalysis with Frustrated Lewis Pairs for Reductive Etherification of Aldehydes and Ketones
Bakos, Mária,Gy?m?re, ádám,Domján, Attila,Soós, Tibor
supporting information, p. 5217 - 5221 (2017/04/27)
Herein we report that a single frustrated Lewis pair (FLP) catalyst can promote the reductive etherification of aldehydes and ketones. The reaction does not require an exogenous acid catalyst, but the combined action of FLP on H2, R-OH or H2O generates the required Br?nsted acid in a reversible, “turn on” manner. The method is not only a complementary metal-free reductive etherification, but also a niche procedure for ethers that would be either synthetically inconvenient or even intractable to access by alternative synthetic protocols.
METHOD FOR THE PRODUCTION OF ETHERS
-
Page/Page column 9, (2008/06/13)
The invention relates to a method for the production of ethers of formula (I), where R1 and R2 independently = H, substituted or unsubstituted, branched or linear 1 - 20 C alkyl chains, substituted or unsubstituted 5 - 8 C cycloaliphatic groups with a ring size of from 5 - 8 carbon atoms, whereby the ring can be interrupted by a heteroatom, or R1 and/or R2 = unsubstituted or substituted aromatic groups or together form a chain of 5 - 7 methylene groups and R3 = linear or branched 1 - 20 C alkyl chains, by hydrogenation of acetals of formula (II), where R1, R2 and R3 have the meanings given above, in the presence of hydrogen on a catalyst comprising copper oxide, aluminium oxide and optionally, in addition, manganese oxide.
A mechanistic survey of the oxidation of alcohols and ethers with the enzyme laccase and its mediation by TEMPO
D'Acunzo, Francesca,Baiocco, Paola,Fabbrini, Maura,Galli, Carlo,Gentili, Patrizia
, p. 4195 - 4201 (2007/10/03)
The oxidation of alcohols and ethers by O2 with the enzyme laccase, mediated by the stable N-oxyl radical TEMPO, affords carbonylic products. An ionic mechanism is proposed, where a nucleophilic attack of the oxygen lone-pair of the alcohol (or ether) onto the oxoammonium form of TEMPO (generated by laccase on oxidation) takes place leading to a transient adduct. Subsequent deprotonation of this adduct a to the C-O bond leads to the carbonylic product. Additional mechanistic considerations for the laccase-mediated oxidation of ethers and thioethers are offered. The proposed mechanism is supported by: (i) investigating the inter- and intramolecular selectivity of oxidation with appropriate substrates, (ii) thermochemical considerations, and (iii) attempting a Hammett correlation for the oxidation of a series of 4-X-substituted benzyl alcohols, wherein a shift of the rate-determining step as a function of the 4-X-substituent results. Based on the above points, the lack of mediation efficiency of another stable N-oxyl radical (viz., IND-O) can be explained. Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2002.
The role of hydrogen migration in the mechanism of alcohol elimination from MH+ ions of ethers upon chemical ionization
Morlender-Vais,Mandelbaum
, p. 1124 - 1132 (2007/10/03)
An enhanced elimination of alcohol under isobutane CI conditions, resulting in highly abundant [MH - ROH]+ ions, has been observed in several primary and secondary ethers having a tertiary β-position (methine), as compared with those with β-methylene. This elimination exhibits a significant degree of stereospecificity in stereoisomeric 2-methyl-1-methoxycyclohexanes 4 and 1-methoxy-trans-decalins 7, affording more abundant [MH - ROH]+ ions in the cis isomers 4c and 7tc than in their trans counterparts 4t and 7tt. These findings suggest involvement of a 1,2-hydride migration from the β- to α-position in the course of the alcohol elimination from the MH+ ions of the above cis-ethers, resulting in tertiary carbocation structures. The proposed mechanism of alcohol elimination is supported by a considerable deuterium isotope effect detected in β-deuterium-labeled cis-2-methyl-1-methoxycyclohexane and by a CID study of the structures of [MH - ROH]+ ions obtained from cis- and trans-1,2-dialkoxycyclohexanes. Ring contraction by a Meerwein-type rearrangement has also been observed in the latter system.
Kinetics and mechanism of the aminolysis of cycloalkylmethyl arenesulfonates
Oh, Hyuck Keun,Song, Se Jeong,Jo, Dong-Soo,Lee, Ikchoon
, p. 91 - 96 (2007/10/03)
Nucleophilic substitution reactions of cycloalkylmethyl arenesulfonates (CmH2n-1 CH2OSO2C6H4Z) with anilines (XC6H4NH2) in methanol at 65.0 °C were studied. The reactivity order (n=4>6>7>5) reflects largely the order of steric effect of the ring size (SEs term) except for n=5, which exhibits the least reactivity. This reversal of the order for n=5 is considered to result from large rate retardation due to polar effect of the ρ*σ* term. Application of the Taft equation to the rate data for n=5 and 6 gives ρ=17·4 and 5=2·3 with correlation coefficient of 0·90. The σ* values for n=4 and 7 are estimated to be - 0·23 and - 0·11, respectively. The positive ρxz values of ca 0·3 are consistent with previous results for the reactions at primary reaction centers.
