Hydrochloric Acid → HCID 13306583, compound

Participants

Reaction Steps

To a solution of 5.66 g (25 mmol) of Pyr-Pro-OH (III) in 60 ml of anhydrous tetrahydrofuran, 2.81 ml (25 mmol) N-methyl-morpholine and 2.48 ml (25 mmol) of ethylchloroformate were successively added at -12° C. After stirring for 2 minutes, a cold solution of 8.85 g (25 mmol) of HCl.H-Trp-Val-OMe (XI) and 2.81 ml (25 mmol) of N-methylmorpholine in 60 ml of dimethylformamide was added. The reaction mixture was stirred for 1 h at -12° C. and for 2 h at 0°-15° C., then filtered to remove salts and evaporated in vacuo. The crude product was purified by column chromatography on silica gel (Merck) 0.040-0.063 mm with an eluent of methylene dichloride:methanol:water in a ratio of 92:8:1 by volume. A 8.37 g (63.7% yield) amount of XII was obtained from isopropyl alcohol/diisopropyl ether. m.p. 120° C. [α]D24 =-76.3° (c=1 MeOH); RfB 0.21; RfC 0.56; Amino acid ratio:Glu 1.00; Pro 0.98; Val 1.00.

Provenance & Evidence