Synthesis of Dalargin, the synthetic Leu-enkephalin analogue in solid phase peptide synthesis

An efficient and fast synthesis of dalargin, a potent synthetic opioid peptide was achieved on gram scale within 2 days, with 98% HPLC purity in solid phase peptide synthesis. Benzoisothiazolone was used as reusable coupling reagent in the present peptide synthesis and was recycled up to 90%. The expensive conventional coupling reagents in the peptide synthesis were replaced by a recyclable and fast coupling reagent there by improving the economic and safety factors of peptide synthesis.