3-(4-Bromothiophenoxy)propionic acid → 6-Bromo-2,3-dihydro-4H-1-benzothiopyran-4-one

Participants

Reaction Steps

200 mL of concentrated sulfuric acid was added to 27.7 g (0.106 mol) of the title compound of Step A. The mixture was stirred at room temperature under nitrogen overnight, and was then poured over crushed ice. The mixture was filtered, and the solid was dissolved in methylene chloride. The resulting solution was dried (MgSO4), filtered, and evaporated to dryness to yield 14.77 g of the title compound of Step B as a solid melting at 50° C. (dec). 1H NMR (CDCl3): δ3.0 (m,2H), 3.2 (m,2H), 7.16-8.2 (3H).

Provenance & Evidence