3.6- Dimethyl-1,2,4-triazine 4-oxide

The halogenation of 3-methoxy- or 3-methyl(dimethyl)amino-1,2,4-triazine 2-oxides 18 was found to proceed in a similar manner, resulting in 6-halo-1,2,4-triazine 2-oxides 19 (77JOC3498, 78JOC2514). 

The reaction of the fervenulin 1-oxides 100 with secondary amines results in contraction of the 1,2,4-triazine ring to form 2-amino-5,7-dimethylimidazo[4,5-e] pyrimidine-4,6(5/7,7//)-diones 101. The reaction of the same fervenulin 1-oxides 100 with ammonia leads to the 1,2,4-triazine ring cleavage product, 1,3-dimethyl-5-imino-6-isonitrosouracil 102 (94KGS1253). 

The reaction of hydroxyamidrazone 134 with dimethylglyoxal in methanol leads to 5,6-dimethyl-3-phenyl-1,2,4-triazine 4-oxide 135 (71LA12). 

Heteroannelated 1,2,4-triazine 4-oxides—fervenulin 4-oxides 12—were obtained starting from 6-hydrazino-l,3-dimethyl-5-nitrosouracil. Orthocarboxylates, formic acid, dimethyl sulfate, or DMF in the presence of POCI3 were used as cyclization agents (77H273, 78JOC175, 78JOC469). 

Treating glycosyl isothiocyanates 415 with 5,6-diamino-1,3-dimethyl-uracil (416) gave thioureas 417, which on oxidative cyclization with N-bromosuccinimide afforded 5,7-dioxopyrimido[5,4- ][1,2,4]triazine nucleosides 418 (80MI1 82MI2). 

A methyl group in the 5-position can be oxidized by potassium permanganate to a carboxyl group, while one in the 3- or 6-position is converted into an oxo group under the same reaction conditions, leading to l,2,4-triazin-3- or -6-ones. Oxidation of 5,6-dimethyl-... 

Oxidation of 3-amino-1,2,4-triazine (39) with peracetic acid led to 3-amino-1,2,4-triazin-5-one (233) (79JHC555) while oxidation with permanganate gave the 3,5-dione (234) (79JHC1649). When 3-amino-5,6-dimethyl-l,2,4-triazine (235) was treated in basic or acidic medium with potassium permanganate the only isolated product was the 3-amino-6-methyl-... 

Dichloro-5,5-dimethyl-2,4-imidazolidindione, 1859 Potassium l,3-dibromo-l,3,5-triazine-2,4-dione-6-oxide, 1028 Sodium l,3-dichloro-l,3,5-triazine-2,4-dione-6-oxide, 1034 1,3,5 -Trichloro-1,3,5 -triazinetrione, 1036... 

Peracetic acid oxidizes 3-phenyl-5,6-dimethyl-1,2,4-triazine 4-oxide to the... 

Monocyclic 1,2,3-triazines, e.g., 199 are hydrolyzed by acid to yield 1,3-dicarbonyl compounds, and 1-benzoylphtha-lazine is hydroxylated with sodium hydroxide in dimethyl sulfoxide to give, after oxidation, 4-benzoyl-l(2//)phthala-zinone 200 <1985CPB4193>. 

E7b/2, 483 6-[CH(OR)J-l,2,4-triazin + Acetyl-cyclopentan 2-Ethoxycarbonyl-4-pentyl- E7b/2, 424 [H2C = CH-C(C5H,) = CH-OR + NC-COOR] Pyridin-l-oxid 4,5-Dimethyl-2-(1-hydroxy-cyclohexyl)- E19d,... 

Dimethylamine and trimethylamine (commercially available), 1,3,5-tri-N-methyl hexahydro-5-triazine (from reaction of formaldehyde and methylamine), tetramethylhydiazine (gift of B. J. Aylett), tetramethylmethylenediamine (from reaction of formaldehyde with dimethylamine), dimethyl- and diethylnitrosamine (from reaction of nitrous acid with the appropriate dialkylamine), diethylmethyl-amine (from reductive methylation of diethylamine), ethylethylideneamine (from reaction of ethylamine and acetaldehyde), and TMT and TET (from oxidation of the appropriate wnst/m-dialkylhydrazine). 

The election-deficient triazine ring 352 is readily attacked by sodium borohydride in methanol to give the 2,5-dihydro-1,2,3-triazines 353 in quantitative yield. Under similar conditions 4,6-dimethyl-1,2,3-tria-zine 1-oxide (354) gave the same compound (353, R = Me) in 85% yield, along with 352 (R = Me). However, reduction of the 1,2,3-triazine 2-oxides 355 left the iV-oxide functionality intact for the most part, giving the 1,4,5,6-tetrahydro-1,2,3-triazine 2-oxides 356 as the major products. Both cis and trans isomers of356 were detected, the former predominating. 

X-ray crystallographic analysis of 6-methyl-4-phenyl-l,2,3-triazine 1-oxide (8),22 1-methyl-4,6-diphenyl-l,2,3-triazinium iodide (9),23 4,6-dimethyl-l,2,3-triazine 2-oxide (10a),19 4,6-diphenyl-1,2,3-triazine 2-oxide (10b),19 4,5,6-triphenyl-l,2,3-triazine 2-oxide (10c),36 4,5,6-tris(4-tolyl)-... 

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