Methyl 3-amino-2-thiophenecarboxylate → HCID 2807589, compound

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Reaction Steps

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

Provenance & Evidence