
%0 Journal Article
%A Collins, David J. 
%A Hughes, Timothy C. 
%A Johnson, Wynona M. 
%T Dihydro-1,2,4-triazin-6(1<emph type="2">H</emph>)-ones. IV. Chemical Modification of 3-Phenyl-4,5-dihydro-1,2,4-triazin-6(1<emph type="2">H</emph>)-ones
%J Australian Journal of Chemistry
%D 2000/05/11
%V 53
%N 2
%P 137-141
%K 
%R https://doi.org/10.1071/CH99156
%U https://www.publish.csiro.au/paper/CH99156 
%X Reaction of 3-phenyl-4,5-dihydro-1,2,4-triazin-6(1H)-one (1) and its 5,5-dimethyl derivative (4) with phosphoruspentasulfide gave the corresponding 6-thiones (2) and (5); methylation of (2) gave the 6-methylsulfanyl-3-phenyl-4,5-dihydro-1,2,4-triazine (3), also obtained by reaction of 6-chloro-3-phenyl-4,5-dihydro-1,2,4-triazine (8) withsodium thiomethoxide. Reaction of (8) with morpholine afforded the 6-(morpholin-4&cent;-yl) derivative (9). Reaction of (1) with isopropyl isocyanate gave N-isopropyl-6-oxo-3-phenyl-1,4,5,6-tetrahydro-1,2,4-triazine-1-carb-oxamide (19a), and a Mannich reaction of (1) with morpholine and formaldehyde gave the 1-morpholinomethylene derivative (20a). Attempts to effect cycloaddition of 1-methyl-3-phenyl-1,2,4-triazin-6(1H)-one (12) with a benzonitrile oxide failed. Reaction of the thione (2) with 1,3-dipolarophiles gave unstable adducts. 
