Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.

The disclosure provides a process for the preparation of 3-(4-annitophenyl)-2-metlioxypropionic acid, and analogs and intermediates thereof, contemplated to be capable of modulating the activity of receptors, e.g., PPARs receptors.

The disclosure provides a process for the preparation of 3-(4-annitophenyl)-2-metlioxypropionic acid, and analogs and intermediates thereof, contemplated to be capable of modulating the activity of receptors, e.g., PPARs receptors.