Hydrochloric Acid → 3-(phenylthio)acrylic acid

Participants

Reaction Conditions

Reaction Steps

Methyl propiolate (3.37 ml, 40.0 mmol) was suspended in aqueous 2.5N NaOH (32.0 ml, 80 mmol), and the resulting mixture was cooled to 0° C. Thiophenol (4.12 ml, 40.0 mmol) was added drop wise under vigorous stirring, and the reaction was left at room temperature for 1 hour. The mixture was diluted with water (30 ml), and the pH was adjusted to 1 with aqueous 10% HCl. The aqueous solution was extracted with AcOEt (2×60 ml) and the combined organic layers were dried over Na2SO4 and evaporated to dryness (presence of two diastereoisomers, Z/E ratio about 90/10). The solid residue was suspended in CH3CN (20 ml) and heated to 40° C. to obtain complete dissolution. The solution was cooled to 0° C. and crystallization of the (Z) isomer was observed. The solid was collected by filtration and dried under vacuum affording (Z)-3-(phenylthio)acrylic acid (299a) (2.67 g, 14.81 mmol, 37% yield, MS/ESI+ 181.3 [MH]+).

Provenance & Evidence