SYNTHESIS OF ACYCLO C-NUCLEOSIDES OF RO[9,10-E][1,2,4]TRIAZINO[3,4-C]-[1,2,4]TRIAZOLES, AND THEIR PRECURSORS

Reaction of 3 -hydrazinophenanthro[9, 10-e][l,2,4]triazine (1) with al iphatic and aromatic aldehydes as well as monosaccharides gave the cor responding hydrazones 2a-g. The D-glucose analogue exists in the cycli c pyranosyl structure 5. Acetylation and partial acetylation of the su gar hydrazones were carried out. Cyclization of a number of hydrazones including the partially acetylated sugar hydrazones by thionyl chlori de gave regioselectively the respective angular isomer 1-substituted p henanthro[9,10-e][ l,2,4]triazino[3,4-c][ 1,2,4]triazoles 16i-l, and n ot the linear isomer. The cyclization of 1 with acetic acid, however, gave regioselectively the linear isomer 19. The structural assignments were based on a model study whereby the angular 16a was found to be d ifferent from the linear isomer 19a obtained by the condensation of 4, 5-diamino-3-methyl- 1,2,4-triazole with 9, 10-phenanthraquinone. Perio date oxidation of 2d gave 20 whose reaction with 1 gave 21.