Carbon Dioxide → 4,5-dihydro-8-(3-methoxyphenyl)-5-thioxo-3H,6H-1,4,5a,8a-tetraazaacenaphthylen-3-one

Participants

Reaction Steps

A mixture of 4,5-dihydro-7-(3-methyoxyphenyl)pyrazolo1,5-a]pyrimidine-3-carboxamide (prepared as described in Example 3) in dry tetrahydrofuran is stirred and cooled at -78° C. (dry-ice, acetone), under nitrogen and two equivalents of sodium hydride (60% dispersion in mineral oil) is added. The mixture is stirred at 78° C. for 30 minutes, then 1,1'-thiocarbonyldiimidazole is added in one portion. The temperature is kept at -78° C. for 2 hours, then the mixture is allowed to warm slowly to room temperature while stirring is continued for 48 hours. The reaction mixture is quenched with water and neutralized to pH 6-7 with 5% aqueous hydrochloric acid. A crystalline solid forms which is collected by filtration, triturated with ether, filtered and dried to give 4,5-dihydro-8-(3-methoxyphenyl)-5-thioxo-3H,6H-1,4,5a,8a-tetraazaacenaphthylen-3-one.

Provenance & Evidence