V-TRIAZOLINES - PART 40 - THERMAL AND PHOTOCHEMICAL-TRANSFORMATIONS OF 1-BIARYL-5-AMINO-4,5-DIHYDRO-V-TRIAZOLES A NEW SYNTHETIC APPROACH TO6-ALKYLPHENANTHRIDINES AND AZA-ANALOGS

1-Biaryl-5-morpholino-v-triazolines 4 were prepared from aliphatic ald ehydes 1, morpholine and 2-azidobiaryls 3. They underwent smooth; ther mal rearrangement to tertiary amidines 5 which were photochemically cy clized to 6-alkylphenanthridines 6a,b,e,f and analogs 6c,d and 8a,b wi th morpholine elimination. Direct photolysis of triazolines 4 afforded lower yields of the same compounds 6 together with by-products indica tive of the mechanism of the photochemical rearrangement which is disc ussed.