Branched polycyclic tetrazole systems. 1. Synthesis and structure of 2-(5-tetrazolyl)ethyl derivatives of some CH-, OH-, and NH-acids

Article abstract of DOI:10.1007/BF02320330

The cycloaddition of dimethylammonium azide to the nitrile groups of 2-cyanoethyl derivatives of CH-, OH-, and NH-acids leads to open-chain branched structures containing terminal NH-tetrazolyl groups. An x-ray diffraction structural analysis of tris[2-(5-tetrazolyl)ethyl]nitromethane revealed steric access of the equivalent NH-tetrazolyl rings of the branched system. In going from the branched nitrile substrates to the corresponding tetrazoles, the PMR spectra show a breakdown in the resolution of the multiplet components, which had not been observed previously for monocyclic 5-substituted tetrazoles. A dependence was found for the ¹³C NMR chemical shifts on the pK_a values, reflecting the NH-addity of the branched polycyclic tetrazoles in water.