3- Phenyl-3 -triazolo quinoline

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 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). 

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. 

AX(C)1119>, 3-(2 -phenyl-quinolin-4 -yl)-[l,2,4]triazolo[3,4-Albenzothiazole 7 <2002JlST41, 2001MI2>,... 

Chloro-2-(3-methyl-4H-l,2,4-triazol-4-yl)benzophenone (Oxidation of 7-chloro-l-methyl-5-phenyl-s-trizolo[4,3-a]quinoline) A stirred suspension of 7-chloro-l-methyl-5-phenyl-s-triazolo[4,3-a] quinoline (2,94 g, 0.01 mol) in acetone (110 ml) was cooled in an ice-bath and treated slowly with a solution prepared by adding sodium periodate (2 g) to a stirred suspension of ruthenium dioxide (200 mg) in water (35 ml). The mixture became dark. Additional sodium periodate (8 g) was added during the next 15 minutes. The ice-bath was removed and the mixture was stirred for 45 minutes. Additional sodium periodate (4 g) was added and the mixture was stirred at ambient temperature for 18 hours and filtered. The solid was washed with acetone and the combined filtrate was concentrated in vacuum. The residue was suspended in water and extracted with methylene chloride. The extract was dried over anhydrous potassium carbonate and concentrated. The residue was chromatographed on silica gel (100 g) with 10% methanol and 90% ethyl acetate 50 ml fractions were collected. The product was eluted in fractions 10-20 and was crystallized from ethyl acetate to give 0.405 g of melting... 

N-C-N side chain was used by Cusmano and co-workers in the preparation of triazolo[l,5-a]quinolines and triazolo[l,5-a]pyridines. The base-catalyzed thermal rearrangement of 1,2,5-oxadiazole 22 afforded the desired triazolo[l,5-a]quinoline (E)-23 in good yield as a single stereoisomer. The expected Z-oxime products readily isomerize to the respective -oximes under the reaction conditions. When the phenyl-substituted 1,2,5-oxadiazole 24 was subjected to the reaction conditions, however, complete isomerization of the products was not observed and a mixture of stereoisomers (E)-25 and (Z)-25 was obtained. 

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