4- Hydroxy-3,4-dihydro- 1,2,4-triazines

The ring-chain isomerism was studied in a series of 4-hydroxy-3,4-dihydro-1,2,4-triazines 87, which are models for cr -adducts at the 3 position of the... 

Phenanthro[l,2-d][l,2,3]selenadiazole, 10,11 dihydro- H NMR, 6, 348 synthesis, 6, 353 Phenanthro[b]thiophenes synthesis, 4, 914 Phenanthro[4,5-bcd]thiophenes synthesis, 4, 883, 907, 914 Phenanthro[9,10-ej[l, 2,4]triazines synthesis, 3, 434 Phenarsazin synthesis, 1, 561 Phenazine dyes, 3, 196-197 nitration, 3, 177 UV Spectra, 2, 127 Phenazine, 3-amino-2-hydroxy-in colour photography, 1, 374 Phenazine, 1-chloro-nucleophilic substitution, 3, 164-165 5-oxide... 

Triazine 4-oxides 55 react with phenols (phenol, 2,6-dimethylphenol, resorcinol, 4-hexyh esorcinol) in trifluoroacetic acid in a similar way, yielding intermediate (T -adducts 5-hydroxyphenyl-4-hydroxy-4,5-dihydro-l,2,4-triazines 61. Subsequent oxidation leads to the corresponding 5-hydroxyphenyl-l,2,4-triazine 4-oxides 62 (97MC116). 

Aus 3-Hydroxy- (bzw. 3-Mercapto)-5,6-diphenyl-1,2,4-triazin wird ein Gemisch aus 1,4-Dihydro- (sehr oxidationsempfindlich) und 4,5-Dihydro-Dcrivat erhalten4 ... 

C7H22N2 140-80-7) see Chloroquinc Mepacnne 7(77)-amino-3-[[(2,5-dihydro-6-hydroxy-2-methyl-5-oxo-l,2,4-triazin-3-yl)thio]mcthyl]-3-cephem-4-carboxylicadd (C12H13N5O5S2 58909-56-1) see Ceftriaxone (15-franx)-l-amino-2,3-dihydro-l//-inden-2-ol (CyH NO 163061-74-3) see Indinavir sulfiite cis-l-amino-2,3-dihydro-l//-inden-2-ol (C9H11NO 7480-35-5) see Indinavir sulfate... 

LA Carpino, J Xia, A El-Faham. 3-Hydroxy-4-oxo-3,4-dihydro-5-aza-benzo-l,2,3-triazine. J Org Chem 69, 54, 2004. 

Amino-4,5-dihydro-5-hydroxy-l,2,4-triazine (82B) exhibits a temperature-dependent equilibrium with the open-chain hydrazide-hydrazone derivative 82A in CDCI3 solution, as shown by the H-NMR data (85LA78). 

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-... 

Dihydroxytriazinylformaldoxime, Dihydroxy-triazinylmethanol Oxime or 3,4-Dihydro-6-hydroxy-4-oxo-s-triazine-2-carboxaldehyde Oxime CA Nomenclature). 

Various extensions are possible (see CHEC 2.19 for full details). Use of aminoguanidines, semicarbazide and thiosemicarbazide gives respectively the 3-amino-1,2,4-triazine, and the 3-one and 3-thione derivatives. Use of a-keto esters and a-keto cyanides gives 5-ones and 5-amino derivatives, respectively. a-Hydroxy ketones afford dihydro-1,2,4-triazines. Intermediates (479) and (480) can sometimes be isolated. 

Data on the structures of monocyclic dihydro- or hexahydro-1,2,3-triazines, on 1,2,3-triazine tV-oxides and 1,2,3-triazinones are not yet available. From studies on the one-electron reduction of the tetrahydro-l,2,3-triazinium salts (7) it was concluded that the heterocyclic ring is flexible and not planar (80LA285). No detailed information on the structure of 3-benzyl-l,5-diphenyl-l,2-dihydro-l,2,3-triazine-4,6(3//,5f/)-dione (8) or of the 6-hydroxy-4-oxo-l,4-dihydro-l,2,3-triazinium hydroxide inner salts (9) seems to be available. 

Reduction of 4-amino-1,2,4-triazin-5-ones (291) affords compounds which were formulated (rather improbably) as 4-amino-5-hydroxy-3,4-dihydro-l,2,4-triazines (292)... 

Hydrazono-l,l,l-trifluoroalkan-2-ones (4) react with aldehydes in the presence of aqueous ammonia to yield 5-trifluoromethyl-2,3-dihydro-1,2,4-triazines which can be oxidised to give 5-trifluoromethyl-l,2,4-triazines (5) or 5-trifluoromethyl-2,5-dihydro-5-hydroxy-1,2,4-triazines (6) [94H(39)155], whilst hydrazines react with a-lactams to give 1,2,4-triazine-3,6-diones [95JOC4121 95JOC5992] (Scheme 3). 

Stabile Derivate des 1,2,4-Triazins (z.B. 3-Hydroxy-5,6-dipnenyl-l,2,4-triazin) konnen unter Erhaltung des Rings Wasserstoff anlagem, wobei im neutralen oder alkali-schen Medium die Dihydro-, im sauren Milieu die Tetrahydro-Derivate entstehen z.B.11 12 ... 

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