1-Piperazinecarboxaldehyde → 2-Cyclopropyl-7,8-dihydro-4-(1-piperazinyl)-6H-thiopyrano[3,2-d]pyrimidine dihydrochloride hemihydrate

Participants

Reaction Conditions

Reaction Steps

A solution of product from Step B (12.1 g), and 1-piperazinecarboxaldehyde (11 ml) in acetonitrile (15 ml) was heated at reflux for 16 hours. The acetonitrile was distilled at reduced pressure and the gummy residue treated with H2O (280ml) and concentrated hydrochloric acid (70 ml) and heated at 95° C. for 1 hour. The solvent was distilled at reduced pressure, the residue treated with ammonium hydroxide, extracted with CH2Cl2 washed with water, brine and dried over K2CO3. The CH2Cl2 was distilled at reduced pressure and the residue chromatographed on silica gel (320 g) eluting with CHCl3.CH3OH (9:1). The pertinent fractions were combined and evaporated, the product dissolved in ethanol (60 ml), treated with 10N sthanolic HCl (10 ml) and ether (60 ml) to give 12.5 g of title compound which melted at 205°-207° C. after recrystallization from ethanol-ether.

Provenance & Evidence