Collect. Czech. Chem. Commun. 1987, 52, 2317-2325

Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

Jan Hlaváčeka,b, Jan Pospíšekb, Jiřina Slaninováb, Walter Y. Chanc and Victor J. Hrubya

a Department of Chemistry, University of Arizona, Tucson, AZ 85721 U.S.A.
b Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6, Czechoslovakia
c Department of Pharmacology, Cornell University Medical College, New York, NY 10021, U.S.A.


[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.