Cyclohexylamine → 4-Hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carboxylic acid cyclohexylarnide

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Reaction Steps

To yield compounds of structure (III) with R2 as carbonitrile, and R1 and R3 as defined above, 4-chloro-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carbonitrile, depicted by formula (50), was used as a key intermediate. To prepare this intermediate, 4-hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carboxylic acid ethyl ester, depicted by formula (40), was reacted with cyclohexylamine to yield intermediate 4-hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carboxylic acid cyclohexylamide, depicted by formula (48). This intermediate was converted to 4,6-dichloro-thieno[2,3-b]pyrdine-5-carbonitrile, depicted by formula (49), by reacting with phosphorous oxychloride, which was then converted into 4-chloro-6-oxo-6,7-dihydro-2-thieno[2,3-b]pyridine-5-carbonitrile, depicted by formula (50), as shown in Scheme 25.

Provenance & Evidence