Use of N-Fmoc Amino Acid Chlorides and Activated 2-(Fluorenylmethoxy)-5(4H)-oxazolones in Solid-Phase Peptide Synthesis. Efficient Syntheses of Highly N-Alkylated Cyclic Hexapeptide Oxytocin Antagonists Related to L-365,209

Article abstract of DOI:10.1021/jo00042a016

Fmoc amino acid chlorides have been shown to be useful reagents in the solid-phase synthesis of hexapeptides containing up to four sequential secondary amino acids.The oxytocin antagonist cyclo-(D-Phe-Ile-D-Pip-Pip-D-(N-Me)Phe-Pro) (1) was prepared in 70p