Temitope O. Olomola

Synthesis and evaluation of coumarin derivatives as potential dual-action HIV-1 protease and reverse transcriptase inhibitors

Baylis-Hillman-derived 3-(benzylaminomethyl)coumarins have been treated, sequentially, with chloroacetyl chloride and propargylamine to afford alkynylated coumarins as substrates for Click Chemistry reactions with azidothymidine (AZT) in the presence of a Cu(I) catalyst. The dual-action HIV-1 protease (PR) and reverse transcriptase (RT) inhibition potential of the resulting N-benzylated cycloaddition products, and a series of non-benzylated analogues, has been explored using saturation transfer difference (STD) NMR, computer modelling and enzyme inhibition techniques.

Novel furocoumarins as potential HIV-1 integrase inhibitors.

A series of seven novel, rationally designed N-substituted 3-{3,5-dimethylfuro[3,2-g]coumarin-6-yl}propanamides have been prepared as potential HIV-1 integrase (IN) inhibitors via a five-step pathway commencing with resorcinol and diethyl 2-acetylglutarate, and the HIV-1 IN inhibition potential of these compounds has been examined relative to raltegravir, a known HIV-1 IN inhibitor.

Convenient Synthesis of 3-Methylcoumarins and Coumarin-3-carbaldehydes

Abstract Rapid, microwave-assisted Baylis–Hillman reactions of substituted salicylaldehydes, followed by one-pot hydrogen iodide–mediated cyclization and reduction of the corresponding adducts, has afforded 3-methylcoumarins in up to 94% yield in the final step. Subsequent microwave-assisted selenium dioxide oxidation of selected 3-methylcoumarins has provided convenient access to the corresponding coumarin-3-carbaldehydes and permitted a significant improvement over the yield obtained using conventional heating. GRAPHICAL ABSTRACT

Elucidating Latent Mechanistic Complexity in Competing Acid-Catalyzed Reactions of Salicylaldehyde-Derived Baylis–Hillman Adducts

(1)H NMR-based kinetic studies have revealed the latent mechanistic complexity of deceptively simple hydrochloric acid-catalyzed reactions of salicylaldehyde-derived Baylis-Hillman adducts. Reactions conducted at 0 °C afforded 2-(chloromethyl)cinnamic acid derivatives as the major products and the corresponding 3-(chloromethyl)coumarin derivatives as the minor products. In reactions conducted in refluxing acetic acid, however, the 3-(chloromethyl)coumarin derivatives are the sole products. Variable-temperature (1)H NMR analysis permitted the determination of the rate constants and kinetic parameters involved in the pseudo-first-order formation of (Z)-2-(chloromethyl)-3-(2-hydroxyphenyl)-2-propenoic acid. The kinetic data clearly preclude the operation of classical kinetic versus thermodynamic control and indicate the operation of three independent reaction pathways. Theoretical studies of these pathways undertaken at the B3LYP/6-31G(d) level permitted rationalization of the experimental data and provided insights into the possible mechanism of the enzymic E-Z isomerization and cyclization of (E)-cinnamic acid analogues to afford coumarins.