Sodium hydride → 4,5-Dihydro-8-phenyl-5-thioxo-3H,6H-1,4,5a,8a-tetraazaacenaphthylen-3-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 7.6 g of 4,5-dihydro-7-phenyl-pyrazolo(1,5-a)pyrimidine-3-carboxamide (prepared as described in Example 25 of commonly assigned U.S. Pat. No. 4,847,256) in 304 ml of dry tetrahydrofuran is stirred and cooled at -78° C., under nitrogen and 2.17 g of sodium hydride (60 percent dispersion in mineral oil) is added. The mixture is stirred at -78° C. for 30 minutes, then 4.84 g of 1,1'-thiocarbonyldiimidazole is added in one portion and the temperature is kept at -78° C. for 2 hours and then is allowed to rise slowly to room temperature. Stirring is continued for 48 hours, and then the reaction mixture is quenched with 500 ml of water and neutralized with 5 percent aqueous hydrochloric acid. A crystalline solid forms which is collected by filtration, triturated with ether, filtered and dried to give 3.2 g of the desired product as white crystals, mp 289-291° C.

Provenance & Evidence