Synthesis of diosgenin derivatives by A and B ring modifications and low-valent titanium (Ti0)-catalysed McMurry coupling reactions and designing to create novel biological agents

Abstract

Diosgenin is a steroidal sapogenin ((25R)-spirost-5-en-3β-ol) occurs abundantly in therapeutic herbs such as Dioscorea alata, Smilax China, and Trigonella foenum graecum. It demonstrates a wide range of pharmacological activities and medicinal properties in a large of experimental and theoretical studies. It also constitutes an important class of compounds for new drug development. In the current study, diosgenin derivatives were synthesized and designed, aiming to discover new steroid-based biological agents. In this work, new diosgenin derivatives were synthesized through low-valent titanium (Ti0)-catalyzed McMurry coupling reaction and structural modifications to the A- and B- rings in the diosgenin. McMurry reaction gave the A-nor and B-nor derivatives in by the intramolecular reductive dimerization of carbonyl compounds in the presence of low-valent titanium agents, in moderate yields (46–47%). The modification reactions on the A and B rings of diosgenin were accomplished by using efficient reagents to give three different series, in moderate to high yields (55–97%). The structures of all novel derivatives were confirmed by FTIR, 1H NMR, 13C NMR, and HRMS methods.