trans-Stereoselective Reduction of Hexahydroquinazoline-2(1H)-thione Derivatives
作者:I. M. Gella、O. D. Bui、A. V. Mirnyi、S. V. Shishkina、O. V. Shishkin、V. D. Orlov
DOI:10.1007/s10593-013-1247-8
日期:2013.5
Reduction of substituted 4-arylhexahydroquinazoline-2(1H)-thiones using NaBH4/CF3CO2H in chloroform gave the corresponding trans-fused octahydroquinazoline-2(1H)-thiones. The use of two reducing systems, NaBH4/CH3CO2H or NaBH4/CF3CO2H, permitted the consecutive trans-selective reduction of the endo- and exocyclic double bond in the case of 8-dithiomethylidene derivatives of hexahydroquinazoline-2(1H)-thiones.
An Efficient and Environmentally Friendly Procedure for the Synthesis of Some Novel 8-Benzylidene-4-phenyl-3,4,5,6,7,8-hexahydro-1H-quinazolin-2-ones/thiones using Tetrabutylammonium Hexatungstate as a Reusable Heterogeneous Catalyst under Solvent-Free Conditions
An efficient method for the preparation of 8-benzylidene-4-phenyl-3,4,5,6,7,8-hexahydro-1H-quinazolin-2ones/thiones from the reaction of aromatic aldehydes with cyclohexanone and urea or thiourea in the presence of Tetrabutylammonium hexatungstate, [TBA]2[W6O19], as an efficient, inexpensive catalyst under thermal and solvent-free conditions has been developed. Good yields, short reaction times, straightforward