Collect. Czech. Chem. Commun. 1979, 44, 2563-2572

Analogues of oxytocin with esters of glutamic acid instead of glutamine in position 4: Synthesis of a compound with high and specific galactogogic activity

Michal Lebl, Tomislav Barth and Karel Jošt

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The reaction of [4-glutamic acid]deamino-1-carba-oxytocin (Ib) with diazoalkanes yielded the corresponding methyl ester Ic and ethyl ester Id. Alternatively, the methyl ester was prepared by means of carbodiimide or thionyl chloride, or by treating the caesium salt of compound Ib with methyl iodide. [2-O-Methyltyrosine, 4-glutamic acid methyl ester]deamino-1-carba-oxytocin (Ih) was also synthetized. The structure of the analogues was verified and their galactogogic and uterotonic activities tested. Compound Ic had the highest galactogogic potency observed as yet (1 307 I.U./mg).