3- -5,6-diphenyl-l,2,4-triazine

The photochemistry of 5-phenyl-l,2,4-thiadiazole 12 is more complicated. Irradiation of compound 12 also gave benzonitrile (58%) along with 3-phenyl-l,2,3-thiadiazole H (18%), phenyl-1,3,5-triazine 13 (4%), diphenyl-1,3,5-triazine 14 (2%), and 3,5-diphenyl-l,2,4-thiadiazole 15 (trace). 3-Methyl-5-phenyl-l,2,4-thiadiazole, when irradiated, affords a similar distribution of compounds. 1SN labeling studies suggested the mechanisms of the transformations all proceed via a common intermediate 16 (Equation 1) <2003JOC4855>. 

Bei der Bestrahlung von 3,5-Diphenyl-l,2,4-oxadiazol in 2-Propanol oder Methanol erhalt man neben Phenyl-chinazolinen auch ringoffene Produkte3,B, wahrend in Diethylether Triphenyl-1,3,4-triazin in geringer Menge nachgewiesen wurde319. 

The tetrazole (66) decomposes to yield nitrogen and a residue consisting of three main components aminodiphenyltriazole, 3,5-diphenyl-l,2,4-triazole and triphenyl-s-triazine (81MIH510, 69USP3442829). The inert nature of the decomposition products makes (66) suitable for use with high temperature polymers such as polycarbonate, polyester and Nylon 6. 

Photolysis of l,6-diazido-2,5-diphenyl-3,4-diaza-2,4-hexadiene (679) afforded 3,6-diphenyl-l,2,4-triazine (680) in 21% yield (72CL1185). 

Many 1,2,4-triazines form complexes with metal ions and can be used for their determination. Thus, 3- and/or 5-(2-pyridyl)-substituted 1,2,4-triazines (e.g. 820) can be used for the determination of iron (II), cobalt(II), nickel(II), zinc(II) and copper(I) ions, thallium and palladium ions can be analyzed by 6-phenyl- (821a) and 5,6-diphenyl-l,2,4-triazine-3-thione (821b), while osmium can be determined by 3-thioxo-l,2,4-triazin-5-one (822), 3-thioxo-dihydro-l,2,4-triazin-5-one (823), 6-mercapto-l,2,4-triazine-3,5-dione (824a), 6-mercapto-5-thioxo-l,2,4-triazin-3-one (824b) and 3,5-dithioxo-l,2,4-triazine-6-carboxyl-ates (825) <78HC(33)189, p. 1004). 

Phenylmagensium bromide reacts with 5-arylmethyl-3-phenyl-l,2,4-triazin-6(l//)-ones to form 5-phenylated products which are easily oxidised to 3,5-diphenyl-1,2,4-triazin-6(lfl)-one. Further derivatives have been obtained by standard metatheses (Scheme 25) 194JCR(S)453]. 

Broad band irradiation of 3,5,6-triphenyl-l,2,4-triazine in neat triethylamine as solvent leads to rapid degradation of the starting material and N-dealkylation of triethylamine to give 2,5-dihydro-3,5,6-triphenyl-l,2,4-triazine, as well as ting-contraction products, 3,5-diphenyl-1,2,4-triazole and 2,3-di(3,5-diphenyl-l,2,4-triazol-l-yl)butane, as a mixture of stereomeric compounds (Scheme 1) <2000MI57>. 

The electrophilic character of 1,2,4-triazines allows their introduction into different other systems. Thus, calix[4]arenes 12 were modified at the meso-carbon atom with a 1,2,4-triazine ring by nucleophilic addition of a calrx-arene lithium derivative to 3,6-diphenyl-l,2,4-triazine 13 with formation of o-adduct 14 which was then oxidized with DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone) giving an aromatic product 15 (13MHC308). 

Pyridyl)-5,6-diphenyl-l,2,4-triazine-p,p -disulfonic acid, monosodium salt (H2O)... 

The synthesis of diphenylmethylpyrimidotriazinones 243 was achieved (86MI2) by the reaction of 3-chloro-5,6-diphenyl[l,2,4]triazine with chlo-ro- or cyanoacetamides in pyridine to give 242, which cyclized with sodium acetate in acetic acid. 

The synthesis of the triazinotriazines 519 was achieved (87MI5) by reaction of 3-hydrazino-5,6-diphenyl[l,2,4]triazine 518 with 4-substituted phenacyl halides. These triazinotriazines were screened against P-388 lymphocytic leukemia in mice and were inactive. 

Azidomethylbenzenediazonium tetrafluoroborate, 2708 Benzenediazonium tetrafluoroborate, 2223 2-Chloro-3-pyridinediazonium tetrafluoroborate, 1816 5-(4-Diazoniobenzenesulfonamido)thiazole tetrafluoroborate, 3119 5,6-Diphenyl-l,2,4-triazine-3-diazonium tetrafluoroborate 2-oxide, 3677... 

Fluoro-5-phenyl-l,2,4-triazine (109, X = F) reacts much faster than the 3-chloro-, 3-bromo-, or 3-iodo-compound. Moreover, the reaction mixture obtained is cleaner than that from the corresponding 3-chloro- or 3-bromo compounds 3-amino-5-phenyl-l,2,4-triazine (110) is formed in good yield. This conversion takes place to only a small extent (18%) via the ANRORC process the main part of the aminodefluorination seems to involve the Sn(AE) mechanism. This result is consistent with the observation that the aminodefluorination of 4,6-diphenyl-2-fluoropyrimidine follows the Sn(AE) process, whereas 2-fluoro-4-phenylpyrimidine (position 6 is vacant for addition of the nucleophile) reacts for the most part according to the Sn(ANRORC) mechanism (see Section II,C,l,c). 

Pyridyl)-5,6-diphenyl-l,2,4-triazine-p,p -disulphonic acid, monosodium salt (H2O) [63451-29-6] M 510.5. Purified by recrystn from water or by dissolving in the minimum volume of water, followed by addition of EtOH to ppte the pure salt. 

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