p-Toluenesulfonic acid monohydrate → 2-(4-Chloro-phenyl)-4,5-dihydro-thieno[2,3-c]pyran-7-one

Participants

Reaction Conditions

Reaction Steps

Dissolve 5-(4-chloro-phenyl)-3-(2-hydroxy-ethyl)-thiophene-2-carboxylic acid methyl ester (3.4 g, 11.46 mmol) in toluene (60 mL) and add p-toluenesulfonic acid monohydrate (0.3 g, 1.58 mmol) and heat to 80° C. for one hour. Cool the mixture to room temperature and dilute with ethyl acetate (50 mL). Wash the solution with 1 N NaOH and extract the aqueous portion twice with ethyl acetate. Combine the organic fractions, dry over Na2SO4, filter, and concentrate. Triturate the solid with ether and then filter and dry under vacuum to give 1.3 g (43%) of the title compound. LC-MS/ES m/z (35Cl) 265.0 [M+H]+.

Provenance & Evidence