Studies in Stobbe condensation. Part 7: Synthesis and biological activity of some new cyclopentadienones and cyclopentadienes.

The condensation of cinnamaldehyde, thienyl and furyl acrolein with dimethyl succinate in the presence of potassium tert-butoxide, gives the corresponding acid-esters (la-c) (R1 = Me) as major products. These esters are further converted into cyclopentadiene and cyclopentadienone derivatives. Dicondensation products (2a-c) are also obtained. Furthermore, the correlation between the chemical structures of the studied compounds and their respective biological activities were discussed.

Novel antimicrobial compounds among naphthalene and methylenedioxyphenyl derivatives.

2-Benzoyl-2-phenyl-4,5,6,7-tetrachlorobenzo-1,3-dioxole (1) undergoes Stobbe condensation readily with dimethylsuccinate in the presence of potassium tert-butoxide to give the acid ester (2a), which is converted into benzocyclopentadienone and naphthalene derivatives via two different routes. The in vitro antimicrobial spectra of these compounds were evaluated. Anhydride (3), phenolic acid (5b), carbamate (5c) and hydrazide (5e) are shown to possess high activity against all tested pathogenic gram-negative organisms in addition to Staphylococcus aureus and the tested yeast species.