UNSATURATED NITROGEN-COMPOUNDS CONTAINING FLUORINE .16. THE SYNTHESIS OF 3,5-BIS(TRIFLUOROMETHYL)-1H-1,2,4-TRIAZOLE AND SOME 4-SUBSTITUTED DERIVATIVES FROM 2,5-DICHLORO-1,1,1,6,6,6-HEXAFLUORO-3,4-DIAZAHEXA-2,4-DIENE

The dichloroazine 5 has been converted into the monoaminoazines CF3C(NHR)=NN=CClCF3 (6) [a, R=Ph (89%); b, R=H (81%); e, R=Me (89%); d, R=CH(2)CO(2)Me (96%); e, R=CH(2)CO(2)Et (95%)] and the diaminoazines CF3C(NHR)=NN=C(NHR)CF3 (4) [c, R=H (96%); d, R=Me (94%); e, R=CH(2)CO(2)Me (50%); f, R=CH(2)CO(2)Et (77%)] by reaction with ammonia or the appropriate primary amino compound; with hydroxylamine the syn-oxime CF3CCl=NNHC(CF3)=NOH (8) (86%) was formed. The mixed diaminoazines CF3C(NHR)=NN=C(NHR')CF3 (4) [g, R=H, R'=Ph; h, R=Me, R'=H; i, R=Me, R'=CH(2)CO(2)Me; j, R=CH2CO2Me, R'=Ph (92%-96%)] have been synthesised from the monoaminoazines 6a-d. A solution of the diaminoazine 49, heated in ethanol under reflux, gave 3,5-bis(trifluoromethyl)-1H-1,2,4-triazole (1a) (28%) and its ammonium salt NH4+[C2N3(CF3)(2)](-) (7b) (54%), while the azines 4g and 4j under the same conditions each afforded 4-phenyl-3,5-bis(trifluoromethyl)-4H-1,2,4-triazole (2c) (ca. 85%). Thermolysis of the diaminoazines 4c-f and 4h in vacuo over the range 120-150 degrees C gave the following results: 4c --> 7b (98%); 4d --> MeNH(3)(+)[C2N3(CF3)(2)](-) (7c) (ca. 26%)+Me(4)N(+)[C2N3(CF3)(2)](-) (7d) (ca. 13%) +4-methyl-3,5-bis(trifluoromethyl)-4N-1,2,4-triazole (2b) (54%) +1-methyl-3,5-bis(trifluoromethyl)-1H-1,2,4-triazole (1b) (1.5 %); 4e --> the 4-carbomethoxymethyltriazole (2e) (93%); 4f --> the 4-carboethoxymethyltriazole (2f) (82%); 4h --> 1a (11%) + 2b (54%) + 7c (31%). Treatment of salt 7b with aqueous hydrochloric acid afforded the triazole la (75%).