Dj. Collins et al., Dihydro-1,2,4-triazin-6(1H)-ones. II - Synthesis of several methylated 3-phenyl-4,5-dihydro-1,2,4-triazin-6(1H)-ones, AUST J CHEM, 52(5), 1999, pp. 379-385
Novel syntheses of 4,5-dihydro-1,2,4-triazin-6(1H)-ones were developed by u
se of imidoyl chlorides. The overall yield of 4,5-dihydro-1,2,4-triazin-6(1
H)-ones prepared from amino acid imidates and hydrazines was improved by th
e development of a much more efficient synthesis of the imidates. The new 1
,2-, 1,4- and 5,5-dimethyl dihydro-1,2,4-triazin-6(1H)-ones have been synth
esized by cyclocondensation/cycloaddition pathways. Base-catalysed methylat
ion of 3-phenyl-4,5-dihydro-1,2,4-triazin-6(1H)-one (15) gave the 1-methyla
ted derivative (8); under similar conditions 2-methyl-3-phenyl-2,5-dihydro-
1,2,4-triazin-6(1H)-one (9) afforded the 1,2-dimethyl derivative (7).