A. M. Dawidar

Xanthanolides from Xanthium spinosum

Abstract The aerial parts of Xanthium spinosum afforded in addition to known xanthanolides three new ones. The structures were elucidated by spectroscopic methods and by partial synthesis. Furthermore one lactone was transformed to a known derivative.

Prenylstilbenes and prenylflavanones from Schoenus nigricans

Abstract The extract of Schoenus nigricans afforded, in addition to a known stilbene and a known prenylflavanone, four new stilbenes and two new prenylflavanones. The structures were elucidated on the basis of spectral data.

A sesquiterpene glucoside from Reichardia tingitana

Abstract Reichardia tingitana var. orientalis afforded, in addition to lupeol, taraxasterol, and the corresponding acetates, three sesquiterpene lactones of the guaianolide type including a new glucoside. The structures were elucidated by spectral methods.

Synthesis and chemical reactions of the steroidal hormone 17α-methyltestosterone

Structural modifications of natural products with complex structures like steroids require great synthetic effort. A review of literature is presented on the chemistry of the steroidal hormone 17α-methyltestosterone that is approved by Food and Drug Administration (FDA) in the United States as an androgen for estrogen-androgen hormone replacement therapy treatment. The analog also offers special possibilities for the prevention/treatment of hormone-sensitive cancers. The testosterone skeleton has important functionalities in the molecule that can act as a carbonyl component, an active methylene compound, α,β-unsaturated enone and tertiary hydroxyl group in various chemical reactions to access stereoisomeric steroidal compounds with potent activity. In addition, microbiological methods of synthesis and transformation of this hormone are presented.

p-Coumaric acid derivatives from Artemisia monosperma.

Abstract Artemisia monosperma afforded four flavonoids, two acetylenes, eight p -hydroxyacetophenone derivatives and three p -coumaric acid derivatives, two of them being new. The structures were elucidated by spectral methods. The flavonoids present are naringenin 7-methyl ether, eriodictyol 7-methyl ether, quercetin 3,7-dimethyl ether and quercetin 7,3′-dimethyl ether.