Acetone Cyanohydrin → 3,3-Dimethyl-1,2,3,4-tetrahydroquinoxalin-2-one

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Reaction Steps

5.4 parts of o-phenylenediamine and 40 parts chloroform are placed in a 250 ml flask, 20 parts 50% by weight NaOH solution is added followed by 0.5 part benzyl triethyl ammonium chloride (BTAC). The flask is cooled in an ice-bath and 5.5 parts acetone cyanohydrin in 10 parts chloroform are added dropwise over 30 minutes. The flask is cooled in the ice-bath for an additional two hours, then warmed and maintained at room temperature for another two hours. Conversion in excess of 90% is obtained. The reaction product is worked up, filtered and washed with CHCl3 several times, and dried to yield 3,3-dimethyl-1,2,3,4-tetrahydroquinoxalin-2-one, which is dissolved in ethanol and conventionally hydrogenated.

Provenance & Evidence