Novel quinolizines and a process for the manufacture thereof and the conversion thereof into other compounds

The invention comprises 2-hydroxy-3-R-6,7-dihydro-4H-benzo[a ]quinolizines of the general formula wherein R is an alkyl or aralkyl group, e.g. a benzyl group, and S stands for 10-methoxy-, 9:10 - dimethoxy -, 9:10 - methylenedioxy-or 8:9:10-trimethoxy-, and acid addition salts thereof, and their preparation by cyclizing the appropriate 1 - [b - [31(41,51) - substituted-phenyl] - ethyl] - 2 - oxo - 4 - ethylene dioxy - 5-(alkyl or aralkyl)-piperidine in a Bischler-Napieralski reaction, treating the cyclized product with dilute mineral acid to hydrolyse the ethylene dioxy group, basifying the resulting compound with dilute alkali and if required converting the resulting base of the above general formula into an acid addition salt by treatment with an acid. The cyclization is preferably effected by heating at 100 DEG C. with phosphorus oxychloride in anhydrous toluene. The quinolizines and their acid addition salts may be converted into the corresponding 3[8,9],10-substituted - 2 - hydroxy - 1:2:3:4:6:7 - hexahydro-benzo[a ]quinolizines by catalytic hydrogenation or reduction with lithium aluminium hydride followed by catalytic hydrogenation. (3) Examples describe the preparation as above of (1) 2-hydroxy-3-ethyl-9, 10-dimethoxy-6:7-dihydro-4H-benzo[b ]quinolizine and its hydrochloride and hydroiodide salts and conversion of the base into the corresponding hexa-hydrobenzo[a ]quinolizine by hydrogenation using palladized charcoal, and the formation of its hydro bromide; (2) 2-hydroxy-3-butyl-9,10-dimethoxy - 6,7 - dihydro - 4H - benzo [a ] quinolizine, its bromide and chloride and (3) 2-hydroxy - 3 - isobutyl - 9,10 - dimethoxy-6,7 - dihydro - 4H - benzo [a ] quinolizine and its chloride and bromide. Specifications 800,969 and 861,524 are referred to.