Cardenolide analogues. Part 12. 13C N.m.r. of semi-synthetic glycosides and side-chain modified genins

Abstract

¹³ C N.m.r. chemical shifts of a number of semi-synthetic cardenolide analogues are presented and the singal assignments justified. Compounds studied include digitoxigenin analogues having αβ-unsaturated 17βside-chains; the α-L-rhamnopyranoside, β-D-glucopyranoside, and β-D-galactopyranoisde of digitoxigenin and/or uzarigenin, and some peracetylated dervatives thereof. The effects of both structural changes in the side-chain and glycoside formation on the chemical shifts of certain carbons on the steroid skeleton are analysed.