O-Phenylenediamine → Thiabendazole

Participants

Reaction Steps

To a 1 liter four-neck flask equipped with a mechanical stirrer, a condenser, pH probe and thermometer were added 54 grams (0.5 mole) of 4-cyanothiazole, 90.5 grams (0.5 mole) of o-phenylenediamine dihydrochloride and 250 ml of deionized water. Sodium hydroxide pellets were added in sufficient proportion to increase the pH of the reaction mixture to a value of 4.0. The mixture was heated to reflux and held at reflux (100°-102° C.) for 4 hours. The reaction was determined to be complete when the peaks corresponding to o-phenylenediamine and 4-cyanothiazole were absent from the gas chromatogram. The reaction mass was allowed to cool to room temperature before adding 0.1N NaOH to adjust the pH to a value within a range of 8-10. The product was filtered, washed three times with 300 ml portions of deionized water, and then dried overnight in a vacuum oven. A total of 78.0 grams of thiabendazole were obtained which corresponds to a 77.5% yield.

Provenance & Evidence