Replacement of dimethylpyrazolyl group in 1,2,4,5-tetrazines by aliphatic alcohols and water
摘要:
Reactions of 3,6-bis(4-R-3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazines and 3-amino-6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazines with aliphatic alcohols and water in the presence of a base involved replacement of the dimethylpyrazolyl group and resulted in the formation of mono- and dialkoxy-1,2,4,5-tetrazines and 6-substituted 3-hydroxy-1,2,4,5-tetrazines. Dissociation constants of the latter were determined by potentiometric titration.
Synthesis of 1,2,4,5-tetrazines, symmetrically and unsymmetrically 3,6-disubstituted by N-nucleophiles
摘要:
6-R-3-(3,5-Dimethylpyrazol-1-yl)-1,2,4,5-tetrazines with aliphatic, cycloaliphatic, and aromatic amines, and also with NH-heterocycles undergo a nucleophilic substitution of the dimethylpyrazole moiety yielding symmetrically and unsymmetrically substituted 1,2,4,5-tetrazines. In the 3,6-diimidazolyl- and 3,6-dibenzotriazolyl derivatives reactions of nucleophilic substitution of the heterocyclic moiety also occur. In some cases an ipsosubstitution of amino, hydrazino, and azido groups is observed.