1-AMINOPHOSPHONIC ACIDS AND ESTERS BEARING HETEROCYCLIC MOIETY .2. PYRIDINE, PYRROLE AND IMIDAZOLE DERIVATIVES

The benzylic amines (benzylamine, benzhydrylamine and benzyl carbamate ) were applied in the synthesis of aminophosphonates derived from pyri dine, pyrrole and imidazole. The Schiff bases obtained from correspond ing heterocyclic aldehydes and benzylic amines were caused to react wi th diphenyl phosphonate or dibenzyl phosphonate to form corresponding heterocyclic aminophosphonates in good yields. The N-(benzylamino)-pho sphonates were deblocked by catalytic hydrogenolysis. The benzhydryl g roup from the phosphonates was removed by acidic hydrolysis, and the c arbobenzyloxy group from the phosphonates can be easy removed by treat ment with a solution of 30% HBr in acetic acid, as well. It was found that during acidic hydrolysis of 2- and 4-pyridylmethylaminophosphonat es a rearrangement occurred, combined with a cleavage of C-P bond in t he phosphonate molecules and subsequent formation of the corresponding amines.