Synthesis of 1‐ and 3‐amino‐5‐t‐butyl‐1H‐ and ‐3H‐v‐triazolo[4,5‐d]pyrimidines as hetaryne precursors

This is the authors' abstract. We don't add key points for this paper.

The synthesis of the title compounds 6 and 8 has first been accomplished by reaction of O ‐mesitylsulfonyl‐hydroxylamine with 5‐ t ‐butyl‐3 H ‐ v ‐triazolo[4,5‐ d ]pyrimidine ( 5 ) whose preparation is reported in detail. However the preferred route for the synthesis of the 3‐amino derivative 8 is based upon the preparation of 3‐benzylideneamino‐5‐ t ‐butyl‐3 H ‐ v ‐triazolo[4,5‐ d ]pyrimidine ( 10 ), followed by the removal of the benzylidene protecting group. This critical step was effected by treatment of 10 with dilute hydrochloric acid, in the presence of 2,4‐dinitrophenylhydrazine. The diazotization of 5‐amino‐4‐hydrazino‐2‐ t ‐butylpyrimidine gave predominantly the tetrazolo[1,5‐ c ]‐pyrimidine 13 along with a small amount of compound 8.