Recrystallization processes

A recrystallization and reprocessing process for the mercaptoalkanoylamino lactam acid of the formula

• wherein
• X1 is a lactam of the formula
• R1 is straight or branched chain alkyl of 1 to 6 carbons, —(CH2)m-aryl, —(CH2)m-substituted aryl, or —(CH2)m-heteroaryl;
• m is zero or an integer from 1 to 6;
• n is zero or one;
• d is zero or one;
• v is one or two;
• Y5 is —CH2—, —S—, or —O— provided that Y5 is —S—or —O—only when d is one;
• Y6 is —S— or —O—;
• R4 and R5 are both hydrogen;
• R6 and R7 are both methyl;
• q is two;
• R10 and R11 are both hydrogen;
• and
• b is zero;
• which comprises adding the mercaptoalkanoylamino lactam acid of forula I to a solvent containing a sufficient amount of an agent that minimizes the amount of the disulfide of the formula
• which, in turn, minimizes the formation of the undesired epimer of the pharmaceutically active compound of formula I and then subjecting the resulting slurry to changes in temperature and/or pH, optionally filtering, and then changing the temperature and/or pH to effect recrystallization.