STABLE ISOLATED SYMMETRICAL ANHYDRIDES OF <i>N</i>_α‐9‐FLUORENYLMETHYLOXYCARBONYLAMINO ACIDS IN SOLID‐PHASE PEPTIDE SYNTHESIS:

Abstract

The synthesis and isolation of symmetrical anhydrides of N α ‐9‐fluorenylmethyloxycarbonyl (Fmoc) amino acids using water soluble carbodiimide is described. These compounds were used in a solid phase peptide synthesis of methionine‐enkephalin on a p‐benzyloxybenzyl ester polystyrene 1% divinylbenzene resin support. Homogeneous free pentapeptide was obtained in 42% overall yield. The Fmoc amino acid symmetrical anhydrides were stable during prolonged storage (2 years at 0°) and offer advantages over present “Fmoc solid phase” methods which use anhydrides formed in situ.