Reactions of activated lupane oxo-compounds with diazomethane: An approach to new derivatives of cytotoxic triterpenes
Abstract
The reactions of diazomethane with activated carbonyl derivatives of lupane were investigated. Previously known cytotoxic oxo-compounds were chosen as substrates, which allowed new information on the structure-activity relationships of this group of compounds to be obtained.
Reactions of lupane derivatives containing an unsaturated aldehyde, α-diketones or 18,19-seco-triketones with diazomethane gave 1,3-dipolar and carbene addition products, for example oxirane and dihydropyrazole derivatives, along with products arising from homologation of cyclic ketones, such as methylenoleth-ers. We synthesised seventeen new compounds containing dihydropyrazole, oxirane, cyclopropane or 3-methoxycyclohex-2-en-1-one rings on the triterpenic skeleton.
All compounds were tested for their in vitro cytotoxic activity against the T-lymphoblastic leukaemia CEM cell line.