Pyridine → 4,5-Dihydro-5-methyl-4-oxopyrano[3,2-b]indole-2-carbonitrile

Participants

Reaction Steps

A mixture of 10.5 g (43.3 mmole) 4,5-dihydro-5-methyl-4-oxopyrano[3,2-b]indole-2-carboxamide, 12.6 g (66.2 mmole) p-toluenesulfonyl chloride, and 10.3 g (10.5 ml, 130 mmole) of pyridine in 55 ml DMF was heated under nitrogen on a steam bath for 4 hr. The cooled mixture was added to 500 g ice/water, stirred for 20 min, and the pink solid was filtered and washed with cold water. Two recrystallizations from ethanol yielded light pink needles of mp 190°-192° C.

Provenance & Evidence