Studies on sulfoxide rearrangements: regioselective synthesis of 3-(aryloxyacetyl)-2,3-dihydrothieno[3,2-c][1]benzopyran-4-ones
作者:K.C Majumdar、S.K Ghosh
DOI:10.1016/s0040-4039(02)00200-9
日期:2002.3
Hitherto unreported 3-(aryloxyacetyl)-2,3-dihydrothieno[3,2-c][1] benzopyran-4-ones 5a–f were synthesised in 70–75% yields by the application of the sulfoxide rearrangement of 4-(4-aryloxybut-2-ynylthio)[1]benzopyran-2-ones 4a–f. The substrates 4a–f were synthesised by phase-transfer-catalysed alkylation of previously unreported 4-mercaptocoumarin.
Studies in Sigmatropic Rearrangement: Synthesis of a [6,6]Pyranothiopyran Ring System by Sequential Claisen Rearrangement and Pyridine Hydrotribromide Mediated Regioselective “6-Endo” Cyclization
作者:K. C. Majumdar、U. K. Kundu、S. K. Ghosh
DOI:10.1021/ol020088g
日期:2002.8.1
afford 4-aryloxymethylthiopyrano[3,2-c][1]benzopyran-5(2H)-ones which are subsequently subjected to heating in o-dichlorobenzene in the presence of N,N-diethylaniline and then treated with pyridinehydrotribromide to give [6,6]pyranothiopyrans in almost quantitative yield.