Hydrazine, propyl- → 2,4,6,7-Tetrahydro-3-phenyl-7-(phenylmethylene)-1-propylthiopyrano[4,3-c]pyrazole

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Reaction Steps

A mixture of tetrahydro-3,5-bis-(phenylmethylene)-4H-thiopyran-4-one (5.84 g, 20 mmole) and n-propyl hydrazine (1.48 g, 20 mmole, CA 59:8724f) in MeOH (100 ml) is heated at reflux temperature for 3 hours. The initial heterogeneous mixture becomes homogeneous after about 0.5 hour. Upon cooling, crystals form and are collected and washed (MeOH) to give 5.0 g, m.p. 106°-118°. Recrystallization from MeOH gives the major product.

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