STUDIES IN SIGMATROPIC REARRANGEMENT: THERMAL REARRANGEMENT OF 3-PROP-2′-YNYLOXYBENZOTHIAPYRAN-4-ONES
作者:K. C. Majumdar、B. Roy
DOI:10.1081/scc-120012988
日期:2002.1
ABSTRACT 3-Prop-2′-ynyloxybenzothiapyran-4-one derivatives (3a–d) were prepared from 3-hydroxy benzothiapyran-4-one (1) and prop-2-ynylic halides (2) in 70–90% yield. The ethers (3a–d) were then heated in refluxing chlorobenzene to give furo[3,2-b]benzothiapyran-9-one derivatives (4a–d) in 87–95% yields. 2-Chloro-2-methylbut-3-yne (2e) on reaction with 3-hydroxybenzothiapyran-4-one (1a) directly afforded