METHOD OF PREPARING HIGH-PURITY BUSPIRON AND ITS HYDROCHLORIDES Russian patent published in 1999 - IPC

FIELD: organic synthesis. SUBSTANCE: high-purity 8-[4-[4-(pyrimidine- 2-yl)piperazine-1-yl] butyl]-8-azaspiro[4,5]decane-7,9-dione (buspiron) with formula I: (I) and its hydrochloride are prepared by catalytic hydrogenation of 8-[4-[4-(pyrimidine-2-yl)piperazine-1-yl]but-2-inyl]- 8-azaspiro[4,5]decane-7,9-dione with formula II: (II) in presence of palladium catalyst or Raney nickel in inert organic solvent. According to invention, at least 40% solution of compound II in organic solvent is continuously added to suspension of catalyst in inert organic solvent with such velocity that weight ratio of compound II to catalyst were (0.01-1):1, after which catalyst is removed and, if desired, compound 1 is either isolated or treated with hydrogen chloride in (i) ethanol or isopropyl alcohol at stirring and temperature 15-40 C to give buspiron-hydrochloride with m.p.188-191 C or (ii) in isopropyl alcohol or ethylacetate at temperature not exceeding 70 C to give buspiron-hydrochloride with m.p.201-203 C. EFFECT: increased purity with no additional purification. 12 cl, 6 ex