L-Glutamine → Boc-L-Valine

Participants

Reaction Steps

A larger excess of 6 to 8 equivalents is used in the coupling of steps (h) and (m) with the tert-butoxycarbonyl-protected amino acids aparagine, glutamine, isoleucine, proline, and threonine. In the cycles following addition of a tryptophane residue, 2% 1,2-ethanedithiol (FLUKA) is added to the deprotection steps (a) and (b) in order to prevent the oxidation of the indole ring. Dehydration of the carboxamide function of glutamine is minimized by preforming the 1-hydroxybenzotriazole ester (0°, 15 min) before addition to the resin in step (h).

Provenance & Evidence