Pentannulation of N-heterocycles by a tandem gold-catalyzed [3,3]-rearrangement/Nazarov reaction of propargyl ester derivatives: a computational study on the crucial role of the nitrogen atom

The tandem gold(I)-catalyzed rearrangement/Nazarov reaction of enynyl acetates in which the double bond is embedded in a piperidine ring was computationally and experimentally studied. The theoretical calculations predict that the position of the propargylic acetate substituent has a great impact on the reactivity. In contrast to our previous successful cyclization of the 2-substituted substrates, where the nitrogen favors the formation of the cyclized final product, the substitution at position 3 was computed to have a deleterious effect on the electronic properties of the molecules, increasing the activation barriers of the Nazarov reaction. The sluggish reactivity of 3-substituted piperidines predicted by the calculations was further confirmed by the results obtained with some designed substrates.

Triazoles with long chain alkyl groups as a potential biological compounds

New series of four compounds was synthesized from multi hydroxyl group compounds such as methyl glycoside by coupling with long-chain alky propargyl ester ( C10, C12, C14 and unsaturated C18) via click chemistry after activation the hydroxyl at C6 position by chlorination with N-chlorosuccinimide NCS and functionalized with sodium azide NaN3. The chemical structures and the purity of the resulting triazoles derivatives was confirmed by elemental analysis (CHN) and spectroscopic analysis 1H NMR & 13C NMR. The biological activity for the target compounds was investigated, and they show good antibacterial and antifungal properties against some selected gram-posative and fungi, which make them suitable for medical applications.

Iodine-promoted stereoselective amidosulfenylation of electron-deficient alkynes

Iodine-promoted three-component synthesis of substituted β-amino sulfides has been developed starting from propargyl ester, aliphatic secondary amine, and disulfide.