Crystalline tetrapeptides with phagocytosis-stimulating activity - prepd. by reaction of a tripeptide with amino acids and purification using partition chromatography

摘要

Title cpds of formula (I) X-L-lysyl-L-prolyl-L-arginine (I) are prepd. by reacting a cpd. (II) H-Lys(BOC)-Pro-Arg-OH (II) with a cpd. (III) X-OH (III) (where X = L- or D-seryl, L- or D-pyroglutamyl or L-threonyl). The free-amino groups of (III) are Z- or BOC-protected. Z-groups are first removed by hydrogenation and the BOC-protected tetrapeptide is purified using partition chromatography, followed by de-protection with acid. (I) has phagocytosis-stimulating activity and may be used alone or together with therapeutically-active substance(s) such as antibiotics or sulphonamides. (I) also remove toxins, esp. endotoxins of Gram-neg bacteria and may be used to prevent toxaemia. The process gives a yield of ca 25% of pure compound.