3-Phenyl triazolo

Phenyl-2, l, 3 -Triazolol-4, 5 4,5-[1.2,3-Triazole] (2-Phenyl-[triazolo[4, 4 4,5-triazole], N-Phenyl-C,C-azimino-osotriazol [Ger] orPhenyl-osotrlazolazimid[Ger]). 

Fig. 3.11. Rearrangement of phenyl thiadiazolo[3,4-o]pyridazine to phenyl triazolo[3,4-o]pyridazines.

A soln. of crude startg. m. in 97%-hydrazine stirred overnight at room temp. -> 7-chloro-5-phenyl-j-triazolo[4,3-a]quinoline (Y 7%) and 4,5-dihydro-5-hy-droxy analog (Y 47%) which can be quantitatively dehydrated by heating in acetic acid. Total Y of 7-chloro-5-phenyl- -triazolo[4,3-a]quinoline 54%. A. Wal-ser, T. Flynn, and R. I. Fryer, J. Heterocyclic Chem. 12, 717 (1975). 

Oxidation of the hydrazone of 2-hydrazinopyrazole (226) with Pb(OAc)4 in CH2CI2 is a two-step reaction. The azine (227) was formed as an intermediate and this underwent ring closure to the 3H-pyrazolo[5,l-c][l,2,4]triazole (228) (79TL1567). A similar reaction applied to the benzal derivative of 2-hydrazinobenzothiazole (229) gave 3-phenyl-[l,2,4]triazolo[3,4-6]benzothiazole (230) together with a by-product (231) (72JCS(P1)1519). 

Reaction of 1-chloroisoquinoline with 5-phenyltetrazole gave 3-phenyl[l,2,4]triazolo[3,4-n]isoquinoline (428). It has been suggested that the initial 2-tetrazolylisoquinoline (425) underwent ring opening to (426) which readily lost N2 giving (427). This nitrilimine is a 1,5-dipole, and on cyclization the [l,2,4]triazolo[3,4-n]isoquino-line (428) is formed (70CB1918). 

A combination of the preceding type of synthesis and of cyclization of 4-amino-5-arylazopyrimidine can be seen in the novel procedure of Richter and Taylor. Proceeding from phenylazomalonamide-amidine hydrochloride (180), they actually close both rings in this synthesis. The pyrimidine ring (183) is closed by formamide, the triazole (181) one by oxidative cyclization in the presence of cupric sulfate. Both possible sequences of cyclization were used. The synthetic possibilities of this procedure follow from the combination of the two parts. The synthesis was used for 7-substituted 2-phenyl-l,2,3-triazolo[4,5-d]-pyrimidines (184, 185). An analogous procedure was employed to prepare the 7-amino derivatives (188) from phenylazomalondiamidine (186). 

Diaminopyrimidines (22) were also cyclized with cyanogen bromide (90JHC851) or phenyl isothiocyanate (97PHA753) to give the corresponding 2-amino- or 2-anilino-l,2,4-triazolo[l,5-c]pyrimidines 30 and 31 respectively (Scheme 15). 

Oxidation of 5-arylazo-6-aminoquinoline 146 with copper sulfate in pyridine gave the corresponding 2-aryltriazolo[4,5-/]quinolines 147. Condensation of halo-genated nitrobenzenes with triazolo[4,5-/]quinoline 145 yielded the appropriate 2H- and 3//-aryl derivatives. The nitration of 3-phenyl-3//-triazolo[4,5-/]quino-line 147 occurred at position 4 of the phenyl ring (Scheme 46) (73T221). 

When 3-phenyl-3//-triazolo[4,5-/]quinoline was heated at 390 00°C, IH-pyrido[2,3-c]carbazole 149 originated. Its structure could be confirmed by unambiguous synthesis from the 8,9,10,1 l-tetrahydro-7//-pyrido[2,3-c]carbazole (52CJC711). 

Phenyl-2//-triazolo[4,5-/]quinoline was prepared and used as optical bright-ener, light, and drug stabilizer (86GEP1), whereas 3,5,7-3//-trimethyl-triazolo[4, 5-/]quinoline was identified by gas chromatography/mass spectrometry as a water pollutant of the Shinano River (Japan) (82MI6). 

Chemicel Name 8-Chloro-1 methyl-6-phenyl-4H-s-triazolo[4,3-a] [1,4]benzodiazepine Common Name —... 

Chloro-1 -methyl-5-phenyl-s-trizolo[4,3-a]quinoline A stirred mixture of 6triethyl-orthoacetate (0.925 g,0.0057 mol) and xylene (100 ml) was refluxed, under nitrogen, for 2 hours 40 minutes. During this period the ethanol formed in the reaction was removed by distillation through a short,glass helix-packed column. The mixture was concentrated to dryness In vacuo and the residue was crystallized from methanol-ethyl acetate to give 1.28 g of 7-chloro-1-methyl-5-phenyl-s-triazolo[4,3-a]-quinoline (83.9% yield). The analytical sample was crystallized from methylene chloride methanol and had a melting point 252.5°-253.5°C. 

Chemical Name 8-chloro-6-phenyl-4H-[1,2,4l-triazolo[4,3-a] [ 1,4] benzodiazepine Common Name -Structural Formula ... 

Most of the reported 1,2,5,6-tetrazocine systems probably do not exist in the monocyclic form but rather as the tetraazapentalene betaine structure (see Introduction) 2 3 7"13 for the tetra-phenyl-substituted system, the compound does actually exist as the mesoionic tetraphenyl-[1,2.3]triazolo[l,2-h][l,2,3]triazole, as determined by H and 13C NMR spectroscopy.15 The following syntheses arc therefore questionable. 

The reaction of 3-hydrazinophenanthro[9,10-e][l,2,4]triazine 742 with carbon disulfide, thiourea, phenyl isothiocyanate, urea, and phenyl isocyanate led [77ZN(B)569] to the formation of phenanthro[9,10-e][l,2,4]-triazolo[4,3-/j][l,2,4]triazines 743. Alkylation of 743 in aqueous alkaline... 

Benzylidenehydrazino-3-methoxyquinoxaline (273) underwent oxidative cyclization to 4-methoxy-l-phenyl[l,2,4]triazolo[4,3-fl]quinoxaline (274) [Cu(OAc)2, AcOH, reflux, 1 h 80% " tetrachlorobenzoquinone, CICH2CH2 Cl, reflux, 90 min 92% " analogs by both procedures]... 

Chloro-2-[l-methyl-4-phenyl(thiosemicarbazido)]quinoxaline (275) gave 7-chloro-3-methyl[ 1,2,4]triazolo[4,3-fl]quinoxalin-3-ium-1 -thiolate (276) (Me2... 

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