反应详情

To prepare compounds of structure (I) with R2 as carbonitrile, and R1 and R3 as defined above, 7-chloro-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carbonitrile, depicted by formula (12), was used as a key intermediate. To prepare this intermediate, methyl-3-amino-thiophene-2-carboxylate was reacted with methylcyanoacetate to yield intermediate 3-(2-cyano-acetylamino)-thiophene-2-carboxylic acid methyl ester, depicted by formula (10). This intermediate was converted to 7-hydroxy-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carbonitrile, depicted by formula (11), by reacting with sodium ethoxide, and was then converted into 7-chloro-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carbonitrile, depicted by formula (12), as shown in Scheme 5.