Piperazine → N-Desmethylzopiclone

Participants

Reaction Conditions

Reaction Steps

Anhydrous piperazine (86 g.) is added to a suspension of 6-(5-chloropyrid-2-yl)-7-oxo-5-phenoxycarbonyloxy-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine (76.4 g.) in acetonitrile (760 cc.). The reaction mixture is stirred for 5 hours at a temperature of about 20° C. and then the insoluble product is filtered off, washed with acetonitrile (3×25 cc.) and with diisopropyl ether (50 cc.). After drying, a product (30.8 g.) is obtained and is dissolved in methylene chloride (750 cc.). A small amount of insoluble matter is removed by treating the solution with decolourising charcoal (2 g.). After filtration, the solution is concentrated to dryness under reduced pressure. 6-(5-Chloropyrid-2-yl)-7-oxo-5-(piperazin-1-yl)carbonyloxy-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine (28.3 g.), which melts at 205° C., is thus obtained.

Provenance & Evidence