Synthesis of Some 1-(Flavon-7-yl)-4,5-dihydro-1,2,4-triazin-6(1H)-ones and Related Congeners

Herein, a selected set of chiral N1-(4-oxochromen-7-yl)-4,5-dihydro-1,2,4-triazin-6(1H)-ones (7a-k / 8a-k) were prepared via direct interaction of L-α-amino esters with N1-(4-oxochromen-7-yl) nitrile imines (generated in situ from their hydrazonoyl chloride precursors 5a,b by the action of triethylamine). These novel dihydrotriazinone-flavone hybrid compounds (7), their 2- methylchromenone analogs (8) and the L-proline homologs (9,10) were characterized by microanalytical and spectral (HRMS and NMR) data. Compounds 7a and 7i displayed good activity against (MCF-7) breast cancer.