Efficient hydrolysis of dithioacetals by the N-fluoro-2,4,6-trimethylpyridinium triflate-water system
摘要:
Dithioacetals including 1,3-dithianes and 1,3-dithiolanes are efficiently cleaved by the title reagent system to the parent carbonyl compounds. The cleavage of diprotected symmetrical alpha-diketones and p-phenylene-diketones gives monoketones in good yields. Amide, 1,3-dioxolane, disulfide, ester, ether, hydroxy, nitrile, nitro, and sulfide functions are relatively stable under the cleavage conditions but thiols are oxidized to disulfides.
Transdithioacetalization of acetals, ketals, oximes, enamines and tosylhydrazones catalysed by natural kaolinitic clay
作者:G. K. Jnaneshwara、N. B. Barhate、A. Sudalai、V. H. Deshpande、R. D. Wakharkar、A. S. Gajare、M. S. Shingare、R. Sukumar
DOI:10.1039/a706475f
日期:——
Natural kaolinitic clay efficiently catalyses the transdithioacetalization of acetals, ketals, oximes, enamines and tosylhydrazones with ethane-1,2-dithiol and propane-1,3-dithiol to produce the corresponding dithiolanes in high yields.
An efficient method has been found for the preparation of cyclic monodithioacetats of 1,3-dicarbonyl compounds usingborontrifluorideetherate as the acid catalyst. Asymmetric 1,3-diketones react regioselectively in most of the cases tried. A study of the 13C and 1H nmr characteristics of these compounds has been carried out.
已经发现使用三氟化硼醚化物作为酸催化剂来制备1,3-二羰基化合物的环状单二硫代乙酸酯的有效方法。在大多数尝试过的情况下,不对称的1,3-二酮会发生区域选择性反应。已经对这些化合物的13 C和1 H nmr特性进行了研究。
The Reaction of 2-Ethoxy-1,3-oxathiolane with Carbonyl Compounds in the Presence of ZnCl<sub>2</sub>or HgCl<sub>2</sub>
In the reaction of 2-ethoxy-1,3-oxathiolane with carbonylcompounds in the presence of ZnCl2 or HgCl2, it has been found that only the breaking of the endocyclic bond (C–O or C–S bond) occurs, while the breaking of the exocyclic C–O bond to give the 1,3-oxathiolan-2-ium ion is unfavorable. This behavior is different from that of 2-ethoxy-1,3-dithiolane, in which the breaking of the endocyclic C–S bond