Phosphorus pentachloride → 1-(3,5-bis-trifluoromethyl-benzyl)-5-chloro-1H-[1,2,3]triazole-4-carboxylic acid ethyl ester

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Reaction Steps

Combine PCl5 (5.73 g, 27.5 mmol) with a solution of 1-(3,5-bis-trifluoromethyl-benzyl)-5-hydroxy-1H-[1,2,3]triazole-4-carboxylic acid ethyl ester (5.30 g, 13.8 mmol) in toluene (150 mL) and heat to 50° C. After 2 h, cool to RT, concentrate solution and dissolve crude material in ether (100 mL). Wash the organic solution with saturated NaHCO3 (2×100 mL) and brine (100 mL), dry, filter, and concentrate. Purify the crude material by passing through a short plug of silica gel using a linear gradient of 50% to 80% EtOAc/hexanes, then recrystallize from 1:1 diethyl ether:petroleum ether (150 mL). MS (ES) 402.0 (M+H)+; 1H NMR (400 MHz, CDCl3) δ 7.88 (s, 1H), 7.76 (s, 2H), 5.67 (s, 2H), 4.43 (q, 2H, J=7.0 Hz), 1.40 (t, 3H, J=7.0 Hz).

Provenance & Evidence