acyclic acetals to the corresponding hydroxyalkyl carboxylic esters and simple esters, respectively. 2-Iodoxybenzoic acid (IBX) in the presence of tetraethylammonium bromide was employed for the reaction in aqueous media. The salient features of the protocol include short reaction time, environmentally benign reagents and solvent, and moderate to high yields. o-iodoxybenzoic acid - acetals - oxidations
Salmi; Kyrki, Suomen Kemistilehti B, 1946, vol. 19, p. 97,100
作者:Salmi、Kyrki
DOI:——
日期:——
A New Approach to the Synthesis of 2-Nitrobenzaldehyde. Reactivity and Molecular Structure Studies
作者:C. Ignacio Sainz-Díaz
DOI:10.1007/s007060270002
日期:2002.1
New approaches to the synthesis of 2-nitrobenzaldehyde by formation and selective isomer separation of 2-nitrophenyl-1,3-dioxolane and further hydrolysis are reported. In this route, the same acidic heterogeneous catalyst is used for 1,3-dioxolane formation and hydrolysis; it can be recycled several times without loss of efficiency. The ortholmeta isomers of 2-nitrophenyl-1,3-dioxolane can be separated by a combination of stereoselective crystallization and fractionated distillation. This new route reduces safety and environmental hazards in the synthesis of 2-nitro- and 3-nitro-benzaldehydes. The molecular structures of the nitro derivatives were confirmed by H-1 and C-13 NMR spectroscopy. The results are in accordance with a non-coplanar conformer of the,2-nitro derivatives (2-nitrobenzaldehyde and 2-(2'-nitrophenyl)-1,3-dioxolane), where the nitro group is twisted with respect to the phenyl ring. In contrary, both the carbonyl and the nitro group are coplanar with the phenyl ring in 3-nitrobenzaldehyde. This result is consistent with the reactivity of the compounds.
Facile oxidative hydrolysis of acetals to esters using hypervalent iodine(III)/LiBr combination in water
作者:Waraporn Panchan、Supanimit Chiampanichayakul、Deanna L. Snyder、Siriporn Yodbuntung、Manat Pohmakotr、Vichai Reutrakul、Thaworn Jaipetch、Chutima Kuhakarn
DOI:10.1016/j.tet.2010.01.098
日期:2010.4
The combination of (diacetoxy)iodobenzene (Phl(OAc)(2), DIB) and lithium bromide (LiBr) efficiently oxidized cyclic and acyclic acetals to the corresponding hydroxyalkyl carboxylic esters and simple esters in good to excellent yields The merits of this reaction are that it employs commercially available and non-explosive hypervalent iodine(III) reagent, water as the solvent, a short reaction tune, and mild reaction conditions (C) 2010 Elsevier Ltd All rights reserved
on the acetal C−O bond in the vicinity of more electron-withdrawing (or less electron-donating) groups. The study also revealed considerable complexity in the cleavage mechanism and that the structural variations in the substrate can significantly alter the reaction pathway. This deprotection strategy was found to be also applicable for 2-thioethanol when released from the corresponding monothioacetal