Ethanol → L-Pyroglutamic Acid

Participants

Reaction Conditions

Reaction Steps

In a 2 L flask equipped with mechanical stirrer and condenser, add ethanol (945 ml) and (±)-2-amino-1,2,3,4-tetrahydro-cyclopenta[b]indole-7-carbonitrile (40 g, 0.203 mmol). Stir the mixture and heat to 60-65° C. until complete solution is achieved. Add D-pyroglutamic acid (28.4 g, 0.192 mmol) and water (55 ml). Heat the mixture to reflux for 20 min. Cool to 40-45° C. over 90 min. Stir at 40-45° C. for one hour, and then cool to 24° C. over 2 h. Stir at this temperature for two additional hours. Isolate a crystalline solid by filtration and wash with a mixture of EtOH/water (95:5) (3×50 mL). Dry the solid in vacuo at 50° C. overnight to give 23 g pyroglutamic acid salt.

Provenance & Evidence