N. Peet
Sep 1, 1984
Citations
0
Influential Citations
4
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
The reactions of secondary amines (pyrrolidine, piperidine and morpholine) with 3,4,5-trichloropyridazine (4) was investigated. With 4 and excess amine, disubstitution occurred in good yield and selectively at positions 3 and 5. Treatment of 4 with 2 equivalents of the amine in ethanol afforded high yields of products resulting from monosubstitution at position 5. 3,4-Dichloro-5-(1-pyrrolidinyl)pyridazine (6a), resulting from 4 and 2 equivalents of pyrrolidine, was converted cleanly to 4-chloro-3-hydrazino-5-(1-pyrrolidinyl)pyridazine (8) with hydrazine hydrate. Pyridazine 8 was cyclized with formic acid to give a 1:1 complex (9) of formic acid and 8-chloro-7-(1-pyrrolidinyl)-1,2,4-triazolo[4,3-b]pyridazine (13). Triazolopyridazine 13 also formed a monohydrate (12) and a monohydrochloride salt (14). Catalytic hydrogenation of 9 gave 7-(1-pyrrolidinyl)-1,2,4-triazolo[4,3-b]pyridazine (3), which was a target compound of this investigation.