4, 5-Substituted Pyridazines. VII. Synthesis and Acylation of 3, 4-Dichloro-5-aminopyridazine.

Abstract

1) The structures of 3, 4-dichloro-5-aminopyridazine (VIII), m.p. 178, ° and 5, 6-dichloro-3-pyridazinol (III), m.p. 203∼204°, were established. (VIII) was obtained from 4-chloro-5-amino-3-pyridazinol (VI) and was identical with the sample derived from 3, 4, 5-trichloropyridazine ; (IV) was characterized as a convenient intermediate for preparing 5-amino-3-pyridazinol (V) and 3, 6-dichloro-4-aminopyridazine (II). 2) Preparations of 5-amino-6-chloro-3-pyridazinol (IV), 3-chloro-4-hydroxy-5-aminopyridazine (XI), and 2-phenyl-7-chloro-oxazolo [4, 5-d] pyridazine (XII) obtained from (VIII) and (XI) were reported.