Acetic Acid → 2-[[(1,1-Dimethylethoxy)carbonyl]amino]-4,5-dimethyl-3-thiophenecarboxylic acid

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Reaction Steps

Ethyl 2-bis(t-butoxycarbonyl)amino-4,5-dimethylthiophene3-carboxylate (13.6 g, 34 mmol) was hydrolysed by refluxing in 70 ml of water and 140 ml of methanol with 7.63 g of potassium hydroxide. Addition of 8.1 ml of acetic acid and stirring overnight precipitated 8.27 g (90%) of 2-t-butoxycarbonylamino-4,5-dimethylthiophene-3-carboxylic acid. M.p. 185° C. (dec.). 1H-NMR (DMSO-d6, δ): 1.5 (s, 9H), 2.15 (s, 3H), 2.2 (s, 3H), 10.4 (s, 1H), 13.1 (br.s, 1H).

Provenance & Evidence