Hydrochloric Acid → alpha-(Difluoromethyl)arginine

Participants

Reaction Steps

To a solution of 2-difluoromethyl-2,5-diamino-pentanoic acid monohydrate monohydrochloride (5 g or 21.13 mmole) in NaOH 2M (8.5 ml) is added at once ethylthiouronium hydrobromide (7.82 or 42.26 mmole). The pH of the solution is adjusted to 10.5 with NaOH 2M and maintained to that value for 4 days. The reaction mixture is then neutralized to pH=7 with 1M HCl and concentrated under reduced pressure. The residue is passed on an Amberlite IR 120 H+ form column. Elution with NH4OH 2M affords 2-difluoromethyl-2-amino-5-guanidinopentanoic acid which is recrystallized from H2O/EtOH (2.3 g) m.p. 257° C.

Provenance & Evidence