Sulfuric Acid → HCID 19025451, compound

Participants

Reaction Steps

To a stirred, warm (40° C.) solution of 10.8 g (0.0648 mole) of potassium iodide in 80 ml of water was added dropwise a solution of 10.0 g (0.0324 mole) of 4-(4-amino-2-chlorophenyl)-3-trifluoromethyl-4,5-dihydro-1-methyl-1,2,4triazol-5(1H)-thione (Compound 94 to Table 1, prepared in Step C of Example 2), 2.70 g (0.389 mole) of sodium nitrite, and 20.0 g (0.204 mole) of concentrated sulfuric acid in 125 g of ice-cold water. The resultant mixture was stirred at 40° C. for three hours. The mixture was cooled and was extracted with methylene chloride. The extract was washed with an aqueous sodium metabisulfite solution. The washed organic phase was dried over anhydrous magnesium sulfate and was filtered. The filtrate was evaporated under reduced pressure, leaving a residue. This residue was purified by column chromatography on silica gel, eluting with petroleum ether:diethyl ether (75:25) to yield 5.0 g of 4-(2-chloro-4iodophenyl)-3-trifluoromethyl -4,5-dihydro-1-methyl-1,2,4-triazol-5(1H)-thione as a solid, mp 117°-119° C., Compound 91 of Table 1. The nmr spectra were consistent with the proposed structure.

Provenance & Evidence