Tetrazolo-triazines, reduction

Reduction of the tetrazolo-triazines (327) with sodium borohydride in methanol afforded the... 

Hydrogenation of tetrazolo[l,5-6][l,2,4]triazines 6 with a palladium on charcoal catalyst stopped after the absorption of 1 molar equivalent of hydrogen and the 7,8-dihydro derivative was isolated. Reduction of the same compounds with sodium borohydride in methanol produces the corresponding 5,6,7,8-letrahydro compounds.376... 

Reduction of tetrazolo[l,5-ft][l,2,4]triazine derivatives (16) was also studied <76JOC4l>. Catalytic hydrogenation resulted in partial reduction at the C(7)—N(8) bond to give (17). Sodium borohy-dride, in contrast, led to the formation of a tetrahydro derivative (19). Behavior of both reduction products (17) and (19) towards nitration reagent was also studied, and nitrations of the NH groups have been detected (i.e., (17) gave the mononitro compound (18), whereas (19) afforded the dinitro derivative (20)). 

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