4,5-Dihydro-2-thiazolamine → 4-[(4,5-dihydro-2-thiazolyl)amino]tetrahydro-3,5-bis(phenylmethylene)-2H-thiopyran-4-ol

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Reaction Steps

A slurry of tetrahydro-3,5-bis-(phenylmethylene)-4H-thiopyran-4-one (5.5 g, 18.9 mmole) in 200 ml of acetone is treated with a solution of 2-amino-2-thiazoline (2.0 g, 19.6 mmole, filtered) in 100 ml of acetone at room temperature. The mixture never becomes homogeneous, but the nature of the solids change (yellow to white). After stirring at room temperature for 2 days, the starting ketone remains as evidenced by tlc. Additional 2-amino-2-thiazoline (1 g, 9.8 mmole, filtered) in 50 ml of acetone is added and the mixture is heated at reflux temperature for 1 day. Upon cooling to room temperature, filtration and washing with acetone affords a combined yield of 6.9 g (92.5%) of product in two crops, m.p. 171°-172.5°).

Provenance & Evidence