Thiabendazole → 1-(2-Benzyloxyethoxycarbonyl)-2-(4-thiazolyl)-benzimidazole

Participants

Reaction Steps

32.2 G. (150 mmoles) of 2-benzyloxyethylchloroformate is added dropwise with protection from moisture to a stirred suspension of 30.1 g. (150 mmoles) of 2(4-thiazolyl)-benzimidazole in 200 ml. of pyridine. The addition is complete in 30 minutes whereupon all of the starting material is dissolved and pyridine hydrochloride begins to precipitate. The reaction mixture is stirred at room temperature for 15 1/2 hours and filtered to remove pyridine hydrochloride. The solid material is washed with a small volume of pyridine and the combined filtrate and washing are evaporated to dryness in vacuo. The residual oil is dissolved in 300 ml. of methylene chloride and allowed to stand during which time a substantial amount of solid material precipitates. The solid is removed by filtration and the filtrate washed twice with 250 ml. of 0.25 N HCl containing ice followed by 200 ml. of saturated sodium bicarbonate solution containing 50 ml. of ice. The methylene chloride fraction is dried with magnesium sulfate, treated with charcoal, filtered and evaporated to dryness in vacuo affording 38.9 g. of a yellow-orange oil which begins to solidify on standing. The material is recrystallized from toluenecyclohexane affording 23.8 g. of 1-(2-benzyloxyethoxycarbonyl)-2-(4-thiazolyl)-benzimidazole, m.p. 93°-95° C.

Provenance & Evidence