Quassinoid derivatives preparation

ABSTRACT This review covers various bioactive quassinoids in Simaroubaceous plants, which show cytotoxic antitumor, anti-tumor-promoter (= inhibitor against TPA-induced EBV-EA activation), anti-HIV, anti-tuberculosis, insect antifeedant, and other biological activities. Stability of quassinoids, the preparation of their derivatives, and their biological activities are also discussed. 

Biologically inactive but easily available chaparrin (244) was converted into potent antileukemic C-15 esters of glaucarubolone (245-247) and quassinoid analogs in which C-15 ester side chain has been replaced by an alkyl or alkenyl group. The synthetic methodology developed and described below has been applied to the preparation of C-15 ester derivatives and quassinoid analogs [120],... 

Quassinoids are natural products formed by oxidative degradation of triterpene derivatives their biosynthetic precursors are similar to those of limonoids but the biosynthetic pathways of quassinoids have not been established so far [1]. At least 351 different natural quassinoids have been described in the literature (Fig. 125.1), and a large number of semisynthetic and synthetic analogues have been prepared for synthesis or medicinal chemistry purposes, mostly in last 30 years [see, for example, 2-4]. Several base skeletons have been described in the literature, and these can be classified into five distinct groups according to the number of atoms of the main chain (Fig. 125.1). 

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