Spectra and structure of 1-aminophthalazines

On the basis of VU and PMR spectroscopic data with the aid of the method of experimental structures and the method of dipole moments it was concluded that the products of the reaction of 1,4-dichlorophthalazine with ammonia, methylamine, and aniline in solutions and in the crystalline form exist primarily as Z conformers of the amino tautomeric form. Conversion to the tautomeric imino form was established for 1-phenylamino-4-chlorophthalazine in a number of solvents. The imines of 2-methyl-4-chlorophthalazine exist as the E isomers.