HDPhe-Leu-MetNH2 hydrochloride → BocPro DBpa Phe-DPhe-Leu-MetNH2

Participants

Reaction Steps

Condensation of each of BocPro-LBpa-PheNHNH2 (1.20 g.) and BocPro-DBpa-PheNHNH2 (0.450 g.) with HDPhe-Leu-MetNH2 hydrochloride salt (Example 23, 1.02 g., 0.445 g.) by the acyl azide method (Yajima et al., Chem. Pharm. Bull., vol. 19, p. 1900, 1971) gave BocPro-LBpa-Phe-DPhe-Leu-MetNH2 in 51% yield and BocPro-DBpa-Phe-DPhe-Leu-MetNH2 in 44% yield. De-t-butoxycarbonylation of BocPro-LBpa-Phe-DPhe-Leu-MetNH2 (0.500 g.) and BocPro-DBpa-Phe-DPhe-Leu-MetNH2 (0.250 g.) using hydrogen chloride in dioxane gave HPro-LBpa-Phe-DPhe-Leu-MetHN2, which was isolated as the amorphous white solid dihydrochloride salt hydrate (2:9) in 53% yield, and HPro-DBpa-Phe-DPhe-Leu-MetNH2, which was isolated as the dihydrochloride salt hexahydrate in 59% yield.

Provenance & Evidence