Ethylmorpholine → Boc-Tyr-(D)Ala-Gly-MePhe methioninol

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Reaction Steps

1.23 g of Boc-Tyr-(D)Ala-Gly-OH is dissolved in 30 ml of THF and cooled to 15°. 0.38 ml of ethylmorpholine are added with stirring followed by 0.39 ml of chloroformic acid iso-butyl ester and stirring continued for 10 minutes. A cold solution of 14 g of TFA.H-MePHe-methioninol and 0.45 ml of N-ethylmorpholine in 12 ml of TFA are added with stirring at -15°. The mixture is stirred for 20 hours at 0°, diluted with 250 ml of acetic acid and washed repeatedly with water, 1 N citric acid, 10% KHCO3 and 30% NaCl solution. The liquid is dried over Na2SO4 and evaporated. The residue is purified chromatographically on kieselgel using a mixture of methanol/CH2Cl2 /50% acetic acid, whereby the title compound is obtained. Decomp. 160°.

Provenance & Evidence