Abstract
In order to examine the physiological activity the arginine-linked cardiotonic steroids have been synthesized as bufotoxin analogs. Resibufogenin 3-suberoyl-p-nitrophenyl ester, derivable from the 3-suberate, was condensed with L-arginine hydrochloride to yield resibufogenin 3-suberoyl-L-arginine. In an analogous manner digitoxigenin 3-suberate was converted into 3-suberoyl-L-arginine, -L-arginyl-L-arginine and -L-arginyl-L-proline via the activated p-nitrophenyl ester. The structure of the product was verified by leading to the pyrimidine derivative, respectively.
