Processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate

A process for preparing a compound of Formula (I):

• or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof, comprising
• (a) contacting a compound of Formula (II):
• or a solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof, wherein R1 is an amino protecting group, with
• NH2—R2
• wherein R2 is hydrogen or an amino protecting group, to provide a compound of Formula (III):
• or a solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof;
• (b) transforming the compound of Formula (III), or a solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof, to a compound of Formula (IV):
• or a solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof;
• (c) deprotecting the —NH—R1 group and, when R2 is an amino protecting group, deprotecting the —NH—R2 group to provide a compound of Formula (I), or a solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof;
• and
• (d) optionally converting the compound of Formula (I), or a solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof, to a salt of the compound.