Condensed Heterotricycles: synthesis of pyridine-annealed dibenz[b,f][l,4]oxazepines

Abstract

Cyclization of N-(2-chloro-5-nitrobenzoyl)-8-hydroxy-l,2,3,4-tetrahydroquinolines (7)-(9) using hot aqueous alkali affords pyridodibenzoxazepinones 10, 11 and 12 respectively. Heating the sodium salts of o-chlorobenzamides (16)-(19) in dimethylformamide affords similar pyrido- dibenzoxazepinones 20, 21, 22 and 23 respectively. Catalytic reduction of the nitrolactam 10 to the amine 33 followed by diazotization and deamination gives 20. Reaction of the nitrochlorobenz- amides 7 and 9'with cyclic secondary bases leads to displacement of chlorine by amines, to give 14 and 15. Nitration of pyridodibenzoxazepinones 11 and 20 affords 31 and 32 respectively. The nitrolactams 12, 11, 22, 32 and 31 are reduced to the respective amines 34-38. Amine 34 is transformed to the chloracetyl (39) and to the morpholinoacetyl derivative (40) and to ethyl (41) and allyl (42) thioureas, while 37 is converted to the aminomethylene malonate 43. LAH reduc tion of 20 gives the pyridodibenzoxazepine 44. A second synthesis of the tetracyclic ring system is by the ring closure of the N-acetylphenoxytetrahydroquinoline 29 by phosphorus pentoxide. 30 is obtained and characterized as the iodide. The sultam 48 analogous to 10 is made from 47 in low yield.