Synthetic applications of bicyclic phosphoric triamides

Abstract

Bis(2-arylaminoethyl)amines cannot be efficiently prepared by the obvious route from bis(2-chloroethyl)amine and anilines, as intramolecular cyclisation to piperazine is favoured over a second substitution to form the open triamine. A series of bis(2¬arylaminoethyl)amines was successfully prepared via a new and general route, the facile cleavage under acidic conditions of the corresponding bicyclic phosphoric triamides. In some cases, the resultant amines were functionalised further, ego yielding the trihydrochloride salts and the tri-N-acetylated derivatives. The base hydrolysis of the bicyclic phosphoric triamides in turn, may lead to the formation of interesting amino acids or zwitterions, as demonstrated for one of the derivatives.