4-(2-Bromoethylsulfonyl)benzonitrile → 4-(2-(3-methyl-1H-1,2,4-triazole-1-yl)ethylsulfonyl)benzonitrile

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Reaction Steps

To a stirred suspension of 10 g of thiosemicarbazide in 100 mL of pyridine was slowly added 7.8 ml of acetyl chloride at 0° C. The temperature was maintained throughout the addition (0-4° C.). The reaction mixture was allowed to warm to room temperature and stirred for 16 h. Evaporation gave 1-acetyl thiosemicarbazide. The crude 1-acetyl thiosemicarbazide was dissolved in 70 mL of MeOH and 12 g of sodium methoxide, and was refluxed for 10 h. The solvent was removed and the residue was dissolved in H2O, then acidified to pH 2 by the addition of 1N HCl. The resulting solid was filtered and washed with H2O to give 3-methyl-1,2,4-triazole-5-thiol. 1 g of 3-methyl-1,2,4-triazole-5-thiol was added to a solution of 61 mg of sodium nitrite in 3 ml of nitric acid and 6 mL of H2O at 0° C. The reaction-mixture was stirred for 1 h at 0° C., and basified with saturated sodium carbonate and concentrated. The residue was dissolved with MeOH and filtered. The filtrate was evaporated to give 3-methyl-1,2,4-triazole. 230 mg of 4-(2-bromoethylsulfonyl)benzonitrile was used in Procedure P with 3-methyl-1,2,4-triazole to yield 4-(2-(3-methyl-1H-1,2,4-triazole-1-yl)ethylsulfonyl)benzonitrile. 310 mg of 4-(2-(3-methyl-1H-1,2,4-triazole-1-yl)ethylsulfonyl)benzonitrile was reacted via Procedure T to give 4-(2-(3-methyl-1H-1,2,4-triazole-1-yl)ethylsulfonyl)benzoic acid.

Provenance & Evidence