Solid phase synthesis and biological activities of [Arg8]-vasopressin methylenedithioether.

Solid phase synthesis of Arg8]-vasopressin methylenedithioether, an analog of vasopressin which contains an extra methylene group between the two sulfur atoms of Cys1 and Cys6, is described. Methylene insertion occurred easily when the thiol free peptide on a solid support was treated with tetrabutylammonium fluoride in dichloromethane at room temperature for 3 h. The uterotonic in vitro, pressor, and antidiuretic activities of the compound were reduced in comparison to Arg8]-vasopressin by one order of magnitude.