1-Mercapto-2-propanone → 1-(7-bromo-4H-thieno[3,2-c]chromen-2-yl)ethanone

Participants

Reaction Steps

To a solution of sodium methoxide (5.57 g, 103 mmol) in 250 ml of methanol at 0° C., mercaptoacetone (5.11 g, 57 mmol) was added portion-wise, and after 15 min., 7-bromo-4-chloro-2H-chromene-3-carbaldehyde (1a) (14 g, 52 mmol) was added to it portion-wise with stirring. After the addition, the ice bath was removed and the product gradually started precipitating out as a yellow solid. Stirring was continued for another 3 h, after which water was added to quench the reaction and the methanol was removed under vacuum. Addition of more water yielded the title compound as a yellow solid (1b) which was filtered and dried (14.1 g, 78%). m/z 308.9 (79Br) & 310.9 (81Br).

Provenance & Evidence