Dicyclohexylcarbodiimide → HCID 178455946, compound

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Reaction Steps

Z-Leu-Val-Ile-His-Lys(BOC)-OMe: 300 mg of Z-Leu-Val-OH, 454 mg of H-Ile-His-Lys(BOC)-OMe (manufactured as discribed in European Patent Applicaiton No. 111 266) and 136 mg of HOBt are dissolved in 5 ml of DMF, cooled to 0° and 198 mg of DCCI are added. After stirring briefly, the whole is left to stand overnight at 0° and for a further 24 hours at room temperature and then the DCH which has crystallised out is filtered off. The filtrate is concentrated in a high vacuum at 40° and the oily residue is dissolved in 12 ml of methanol/glacial acetic acid/H20 (94:3:3) and heated for 1 hour at 60°. The solution is again concentrated to dryness and the residue is purified by Craig distribution in the system methanol/acetate buffer/ethylene chloride/chloroform 10:3:8:4 (acetate buffer: 14.3 ml of glacial acetic acid and 9.6 g of ammonium acetate in 1000 ml of water) over 800 stages. The fractions pure according to thin layer chromatography (K=0.26) are combined, concentrated to dryness, pulverised and subsequently dried in a high vacuum at 40°. Rf (B17)=0.70, Rf (S4)=0.75.

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