4-Cyanothiazole → Thiabendazole

Participants

Reaction Conditions

Reaction Steps

The mixture was heated and when the pot temperature reached 164° C., distillation commenced. The temperature gradually increased to 201° C. and a total of 44 ml of water plus ethylene glycol distillate were removed. The mixture was allowed to cool to 100° C. before 27.5 g (0.25 moles) of 4-cyanothiazole were added to the solution containing o-phenylenediamine monohydrochloride. The reaction mixture was heated to 125° C. and held within a temperature range of 125°-130° C. for a period of 5 hours. Thiabendazole formed as a precipitte during the 5 hours of heating. The reaction was monitored by gas chromatography and determined to be complete when the peaks corresponding to o-phenylenediamine and 4-cyanothiazole were negligible. Next, the reaction mass was cooled to 50° C. and filtered to collect the precipitate using a Buchner funnel and #4 Whatman filter paper. The wet cake was washed with 1.5 L of deionized water. The washed precipitate was dried overnight in a vacuum oven under 15-20" Hg and at a temperature of 90° C. The weight of dry thiabendazole crystals was 38.0 g, which corresponds to a yield of 75.5%. The purity was determined to be 99.67% (based on area %) using HPLC analysis.

Provenance & Evidence