Hydrochloric Acid → HCID 178476726, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of 7.64 g of L-pyroglutamyl-L-histidine hydrazide in a mixture of 95 ml of dimethyl sulphoxide and 125 ml of dimethylformamide was treated at -20° C with 104 ml of 1.64-N HCl in tetrahydrofuran. 5 ml of isoamyl nitrite were added to this solution. The mixture was stirred for 30 minutes at -20° C, cooled to -30° C and neutralised at this temperature with 23.7 ml of triethylamine. 7.7 g of L-prolyl-β-alaninamide hydrochloride were dissolved in a mixture of 20 ml of dimethyl sulphoxide and 15 ml of dimethylformamide. cooled to -10° C, neutralised with 4.9 ml of triethylamine and added to the previously described mixture. The thus-obtained mixture was stirred for 1 hour at -20° C, stored for 24 hours at 4° C and filtered. The filtrate was concentrated in vacuo, the residue taken up in 350 ml of water and extracted five times with 70 ml of ethyl acetate each time. The aqueous phase was concentrated in vacuo and the residue purified by countercurrent distribution in 1-butanol/glacial acetic acid/water (4:1:5). L-pyroglutamyl-L-histidyl-L-prolyl-β-alaninamide acetate was obtained by concentration of the appropriate fractions in vacuo and subsequent lyophilisation. [α]D25 = -83.4° (c = 1 in 1 N acetic acid).

Provenance & Evidence