Evaluation of new base-labile 2-(4-nitrophenylsulfonyl) ethoxycarbonyl (Nsc)-amino acids for solid-phase peptide synthesis

J Pept Res. 2000 Aug;56(2):70-9. doi: 10.1034/j.1399-3011.2000.00759.x.

Abstract

The 2-(4-nitrophenylsulfonyl)ethoxycarbonyl (Nsc) group is a new base-labile protecting group for solid-phase peptide synthesis, completely interchangeable with the fluorenylmethoxycarbonyl (Fmoc) protecting group, but with certain advantages. In this paper, we report a methodology with Nalpha-Nsc-protected amino acids for the synthesis of some melanotropins important to our research, namely, gamma-melanocyte-stimulating hormone (gamma-MSH), its [Nle3]-analogue, and a cyclic alpha-MSH/beta-MSH hybrid. We developed an efficient protocol for the synthesis of the cyclic MSH analogue that yielded this peptide in >98% purity. The gamma-MSH synthesis, which gave problems with both the Boc and Fmoc strategies, yielded the desired peptide by Nsc-chemistry but was accompanied by side products. Finally, the Nle3-gamma-MSH analogue was synthesized more efficiently using the Fmoc strategy, suggesting that Nsc-chemistry might not be the best methodology for certain sequences.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / chemistry*
  • Disulfides / chemistry
  • Evaluation Studies as Topic
  • Fluorenes / chemistry*
  • Melanocyte-Stimulating Hormones / chemical synthesis
  • Melanocyte-Stimulating Hormones / chemistry*
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptide Biosynthesis*

Substances

  • Amino Acids
  • Disulfides
  • Fluorenes
  • Melanocyte-Stimulating Hormones