Hydrochloric Acid → 2-(3-Methylthiophen-2-YL)acetic acid

Participants

Reaction Conditions

Reaction Steps

112.5 ml (116 g, 2.312 mol) of hydrazine hydrate were added slowly to a solution of 90 g (0.489 mol) of methyl (3-methylthiophen-2-yl)oxoacetate in 260 ml of diethylene glycol, and the mixture was heated at reflux for 30 min. After cooling to 30-40° C., 82 g (1.246 mol) of potassium hydroxide were added a little at a time, which was associated with a temperature increase to 70-80° C. with simultaneous evolution of nitrogen. The mixture was then slowly heated to reflux and stirred at this temperature for a total of 5 h. After cooling to room temperature, the mixture was poured into 2 l of water, adjusted to pH=1 using 250 ml of semiconcentrated hydrochloric acid and extracted with ethyl acetate. Drying of the organic phase over magnesium sulphate, filtration and removal of the solvent gave 50 g of (3-methylthiophen-2-yl)acetic acid. Yield: 66%. 1H-NMR (DMSO): δ=7.25 (d, 1H), 6.84 (d, 2H), 3.67 (s, 2H), 2.11 (s, 3H).

Provenance & Evidence