Process for the preparation of a substituted 2,5-diamino-3-hydroxyhexane

A process for the preparation of the substantially pure compound of the formula:

• ##STR22## wherein R.sub.6 and R.sub.7 are independently selected from ##STR23## wherein R.sub.a and R.sub.b are independently selected from hydrogen, loweralkyl and phenyl and R.sub.c, R.sub.d and R.sub.e are independently selected from hydrogen, loweralkyl, trifluoromethyl, alkoxy, halo and phenyl;
• and ##STR24## wherein the naphthyl ring is unsubstituted or substituted with one, two or three substitutents independently selected from loweralkyl, trifluoromethyl, alkoxy and halo;
• or R.sub.6 and R.sub.7 taken together with the nitrogen atom to which they are bonded are ##STR25## wherein R.sub.f, R.sub.g, R.sub.h and R.sub.i are independently selected from hydrogen, loweralkyl, alkoxy, halogen and trifluoromethyl;
• or an acid addition salt thereof, comprising reacting an enaminoketone compound of the formula:
• ##STR26## wherein R.sub.6 and R.sub.7 are defined as above with hydrogen gas in the presence of a hydrogenation catalyst and from about 2 molar equivalents to about 4 molar equivalents (based on the enaminoketone) of an acid.