Tetrazoloazines. 15N nuclear magnetic resonance and infrared absorption spectroscopy

Abstract
The reaction of 4‐chloro‐2‐phenylquinazoline with K15NN2 has been studied by 15N‐NMR. spectroscopy. 15N‐chemical shifts in 5‐phenyl‐1 (3)‐[15N]‐tetrazolo[1,5‐c]quinazoline and ‐Nα(Nγ)‐[15N]‐4‐azido‐2‐phenylquinazoline are reported. The characteristic IR. absorption frequencies of the tetrazole group have been determined in a series of annelated 15N‐labelled compounds. From these studies and the chemistry of the labelled tetrazoles, it is concluded that all haloazines examined react with KN3 by the direct nucleophilic substitution mechanism. An addition of nucleophile‐ring opening‐ring closure (ANRORC) mechanism was not observed. The synthesis of several 15N‐labelled tetrazoloazines is described.