4-nitrobenzo[b]thiophene-2-carboxylic acid synthesis

Yield:19995-46-1 162 mg

Reaction Conditions:

with lithium hydroxide monohydrate in methanol;water at 80; for 4 h;

Steps:

9

A mixture of 180 mg of methyl 4-nitrobenzo[b]thiophene-2-carboxylate, 48 mg of lithium hydroxide monohydrate,2 ml of water, and 4 ml of methanol was stirred for 4 hours at 80°C. After the reaction mixture was cooled to roomtemperature, 10 ml of 0.5 M aqueous hydrochloric acid solution was added thereto. The precipitated solids were collectedby filtration and dried under reduced pressure, thereby obtaining 162 mg of 4-nitrobenzo[b]thiophene-2-carboxylic acid(hereinafter, described as a "compound 17 of the present invention").1H-NMR (DMSO-D6) δ: 14.03 (br s, 1H), 8.59-8.58 (m, 2H), 8.44-8.42 (m, 1H), 7.78-7.76 (m, 1H).

References:

EP2926660,2015,A1 Location in patent:Paragraph 0269; 0270