SOME 2,3-FUSED DIAZA-HETEROCYCLES OF ESTRA-1,3,5(10)-TRIEN-17-1

Nitration of 3-aminoestra-1,3,5(10)-trien-17-one (7) in concentrated sulfuric acid afforded 3-amino-2-nitroestra-1,3,5(10)-trien-17-one (8). Refluxing of 8 in formic acid with 10% palladium on carbon gave estra-1,3,5(10)-trieno[2,3-d]imidazol-17-one (1). Diazotization of 8 followed by treatment with sodium azide furnished 3-azido-2-nitroestra-1,3,5(10)-trien-17-one (14) which in refluxing toluene gave estra-1(10),4-dieno[2,3-c][1',2',5'] oxadiazol-17-one 2'(and 5' )oxide (2). The N-oxide was deoxygenated with triphenylphosphine to estra-1(10 ),4-dieno[2,3-c][l',2',5']oxadiazol-17-one (3). Reduction of 8 with zinc-acetic acid gave 2,3-diaminoestra-1, 3,5(10)-trien-17-one (15) which on reaction with nitrous acid provided estra-1,3,5(10)-trieno[2,3-d][1',2',3'] triazol-17-one (4). Treatment of the diamine 15 with sulfur dioxide in dimethylformamide solution gave estra-1(10),4-dieno[2,3-d][2',1',3']thiadiazol-17-one 5). The furoxan derivative (2) was shown to exist as a rapidly equilibrating mixture of the two N-oxide isomers at room temperature. © 1968.