Methyl 4-aminothiophene-3-carboxylate Hydrochloride → HCID 59702106, compound

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Reaction Steps

A preferred intermediate in the preparation of a compound of formula (II) is 4-chloro-1,2-dihydro-2-oxo-thieno[3,4-b]pyridine-3-carboxylic acid ethyl ester, depicted by formula (25) below. To prepare this intermediate, 4-amino-thiophene-3-carboxylic acid methyl ester hydrochloride, depicted by formula (21), was reacted with ethylmalonyl chloride to yield intermediate 4-(2-ethoxycarbonyl-acetylamino)-thiophene-3-carboxylic acid methyl ester, depicted by formula (22). This intermediate was converted to 7-hydroxy-5-oxo-4,5-dihydro-2-thia-4-aza-indene-6-carboxylic acid ethyl ester, depicted by formula (23) by reacting with sodium ethoxide, and was then converted into 5,7-dihloro-2-thia-4-aza-indene-6-carboxylic acid ethyl ester, depicted by formula (24). Hydrolysis 5,7-dihloro-2-thia-4-aza-indene-6-carboxylic acid ethyl ester, depicted by formula (24), yielded 7-chloro-5-oxo-4,5-dihydro-2-thia-4-aza-indene-3-carboxylic acid ethyl ester, depicted by formula (25), as shown in Scheme 11.

Provenance & Evidence