Water → α-Methyl-4-thiazoleacetic acid

Participants

Reaction Steps

A solution of 5.0 g (27 mmol) of ethyl 2-(1,3-thiazol-4-yl)propanoate from step A above in 25 mL of methanol was added dropwise to a mixture of 6.6 mL (33 mmol) of a 5 N aqueous NaOH solution, water (16 ml) and methanol (30 ml). After addition was complete the mixture was stirred for 2 h. The methanol was removed by evaporation and the pH of the remaining aqueous was adjusted to ˜2.5 with a concentrated hydrogen chloride solution. The mixture was saturated with solid sodium chloride and extracted with EtOAc (3×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate and treated with activated charcoal overnight. The mixture was filtered and evaporated to afford the title compound as an off-white solid 4.0 g (95%). 1H NMR (500 MHz, CDCl3) δ: 1.63 (d, J=7.3, 3H), 4.11 (q, J=7.3), 7.25 (d, J=1.8, 1H), 8.88 (d, J=1.8, 1H), 10.25 (br s, 1H).

Provenance & Evidence