Oxalyl chloride → HCID 15565856, compound

Participants

Reaction Steps

The preferred intermediate in the preparation of compounds of structure (I), 7-chloro-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester depicted by formula (4) below, was also prepared by an alternative route as shown in Scheme 34. In this method, methyl-3-amino-thiophene-2-carboxylate was reacted with 4-methoxy benzylchloride to yield methyl 3-(4-methoxybenzylamino)thiophene-2-carboxylate, depicted by formula (65). This intermediate was reacted with ethylmalonyl chloride followed by a cyclization reaction to yield 7-hydroxy-4-(4-methoxybenzyl)-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester, depicted by formula (67). Chlorination of 7-hydroxy-4-(4-methoxybenzyl)-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester, depicted by formula (67) by reacting with oxalyl chloride followed by deprotection yielded the intermediate 7-chloro-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester, depicted by formula (4), as shown in Scheme 34.

Provenance & Evidence