Abstract

STUDIES ON 6-METHYL-4-HYDROXY COUMARIN AND SULFOXIDE REARRANGEMENT: AN ECO-FRIENDLY SYNTHESIS OF 3-(ARYLOXYACETYL)-2,3-DIHYDROTHIENO[3,2-C][1]-8-METHYLBENZOPYRAN-4-ONES.

S. K. Ghosh*

ABSTRACT

Through phase transfer-catalysed alkylation of 6-methyl- 4-mercaptocoumarin 3 with 1-chloro-4-aryloxybut-2-yne 4(a-f), starting substrates 4-[4-aryloxybut-2-ynylthio] [1] – 6 -methylbenzopyran-2-ones 5(a-f) were prepared in 80-87% yield by. 5(a-f) upon [2,3] sigmatropic or sulfoxide rearrangement yielded 3-(aryloxyacetyl)-2,3-dihydrothieno[3,2-c][1]-8-methylbenzopyran-4-ones with 80-90% yield through treatment with metachloroperoxybenzoic acid followed by refluxing in carbon tetrachloride.

Keywords: Sulfoxide rearrangement, 6-methyl- 4- mercaptocoumarin, 1 – chloro – 4 – aryloxybut – 2 – yne Metachloroperoxybenzoic acid, Phase-transfer catalyst.