Acetate → HCID 67852048, compound

Participants

Reaction Steps

Condensation (two runs) of ##STR106## (mixture of isomers, 31.4 mg., 400 mg.) and H-trp-Leu-Phe-NH2 (example 2, 77.5 mg., 556 mg.) using dicyclohexylcarbodiimide (17.2 mg., 220 mg.) and N-hydroxysuccinimide (9.6 mg., 123 mg.) in tetrahydrofuran (1 ml. 10 ml.) at 0° C. for 0.5 hr. and then at room temperature (overnight, 6 hr.), combination of the crude products, and purification by column chromatography on silica gel first with ethyl acetate-pyridine-acetic acid-water (900:54:16:30) as eluant to give ##STR107## as a mixture of isomers (350 mg., 37% yield) and then with ethyl acetate-pyridine-acetic acid-water (1500:54:16:30) as eluant gave isomer A (75 mg.) and isomer B (125 mg.). Lyophilization of isomer A from acetic acid followed by conversion into the phosphate salt by ion exchange chromatography followed by lyophilization from water-acetic acid (95:5) gave ##STR108## phosphate (1:1) salt as an amorphous pale yellow solid (19 mg.).

Provenance & Evidence