3.5- Dioxo-2,3,4,5-tetrahydro-1,2,4-triazin

According to systematic triazine nomenclature, 6-azauracil is 3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine (42). The indexes of the Chemical Abstracts describe it as as-triazine-3,5(2H,4H)-dione. In addition ... 

Hydrazination of 4-aryl-3,5-dioxo-2,3,4,5-tetrahydro-l,2,4-triazine (66) also affords a rearranged product, 4-amino-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine (81JHC953). This replacement of the A-aryl group by the N-amino group requires the intermediacy of the ring-opened compound 67. This intermediate could be isolated under mild conditions and its structure was proven by an independent synthesis. From this structure it can be concluded unequivocally that the ring transformation involves initial addition of the hydrazine at C-5 and not at C-3 (Scheme III.37). 

Chemical Name Sodium salt of (6R,7R)-7-[2-(2-amino-4-thiazolyl)-2-(methoxyimino)ace-tamido] -8-oxo-3-[[(1,4,5,6-tetrahydro-4-methyl-5,6-dioxo-as-triazin-3-yl)thio] methyl] -5-thia-1 -azabicycio [4.2.0] oct-2-ane-2-carboxylic acid... 

H-Pyrazino[l,2-a][l,3,5]triazine, 2-amino-8-methyl-4,9-dioxo-cis-6,7-diphenyl-6,7,8,9-tetrahydro-... 

According to the triazine nomenclature, 5-azauracil is 2,4-dioxo-l,2,3,4-tetrahydro-l,3,5-triazine (2). The subject index of Chemical Abstracts prefers s-triazine-2,4(lH,3H)-dione. Furthermore, some authors use a name derived from the lactim structure, 2,4-dihydroxy-s-triazine (3). The numbering of the substituents is the same for all these types of nomenclature. 

In this connection the possibility of oxidation of these substances to the tetrahydro derivatives should be mentioned. It was made use of by Thiele and Bailey for the preparation of 6-methyl-3,5-dioxo-2,3,4,5-tetrahydro-l,2,4-triazine (6-azathymine) (46) and only recently by Grundman et al. for that of 6-azauracil (42). 

It was observed already by BougaulU that the reaction of 6-benzyl-3,5-dioxo-2,3,4,5-tetrahydro-l,2,4-triazines with alkyl halides in an alkaline solution yields a mixture of the 4-mono- and 2,4-dialkyl derivatives. This mixture of alkylation products can be readily sepa-... 

By comparing the dissociation constant of 6-azauracil and 6-aza-uridine with those or uracil and uridine, 6-azauridine is now considered to be 1-ribofuranosyl derivative (2-ribofuranosyl-3,5-dioxo-2,3,4,5-tetrahydro-l,2,4-triazine), The same was shown more exactly by comparing the UV and IR spectra and the dissociation constants of 6-azauridine with the two monomethyl derivatives of 6-aza-uracil," Enzymatic synthesis thus, proceeds, in the same way in natural bases and in their aza analogs. 

Alkyl and 6-aryl derivatives of 3,5-dioxo-2,3,4,5-tetrahydro-l,2,4-triazine or of its thio analogs have been mentioned before in this review (e.g., Section II,B,2,a). Some of theih contained functional... 

Most of the reported triazinothiadiazines have been prepared from 1,2,4-triazine derivatives. Treatment of amino-1,2,4-triazine 28 with chloroacetyl chloride in dioxane in the presence of triethylamine at 10 °C resulted in the formation of 6-methyl-4-(A -chloroacetamido)-3-thioxo-5-oxo-2,3,4,5-tetrahydro-l,2,4-triazine 29 and 3-methyl-4,7-dioxo-4,6,7,8-tetrahydro-l,2,4-triazino[3,4-A][l,3,4]thiadiazine 15 (Scheme 1) <2005JHC935>. 

Ceftriaxone Ceftriaxone, 7-[[(2-amino-4-lhiazolyl)-2-(Z)-(methyoximino)acetyl]amino]-8-oxo-3-[[(l,2,5,6-tetrahydro-2-methyl-5,6-dioxo-l,2,4-triazin-3-yl)thio]methyl]-5-thia-l-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid (32.1.2.72), is synthesized by acylating 7-amino-3-[[(2,5-dihydro-6-hydroxy-2-methyl-l,2,4-triazin-5-on-3-yl)thio]methyl]3-cefem-... 

H-Purin 3,7-Dimethyl-2,6-dioxo-l-(5-oxo-hexyl)-l,2,3,6-tetrahydro-E18, 1091 (En - On) 1,3,5-Triazin 2-(4-Amino-2-meth-oxy-phenyl)-4,6-dioxo-1,3,5-trimethyl-hexahydro- E3, 113 (Ar-CHO + R-NH-COOH)... 

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