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 g 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