B. Sreedhar

Direct One-Pot Reductive Amination of Aldehydes with Nitroarenes in a Domino Fashion: Catalysis by Gum-Acacia-Stabilized Palladium Nanoparticles

This note describes the direct reductive amination of carbonyl compounds with nitroarenes using gum acacia-palladium nanoparticles, employing molecular hydrogen as the reductant. This methodology is found to be applicable to both aliphatic and aromatic aldehydes and a wide range of nitroarenes. The operational simplicity and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of carbonyl compounds.

CuI nanoparticles for C-N and C-O cross coupling of heterocyclic amines and phenols with chlorobenzenes.

Employing CuI nanoparticles as an efficient catalyst for the cross-coupling reactions of various N/O nucleophilic reagents with aryl chlorides could be successfully carried out under mild conditions in the absence of both the ligands and strong bases. A variety of products including N-arylimidazoles and aryl ethers were synthesized in good to excellent yields.

Synthesis and Antitumor Evaluation of Nitrovinyl Biphenyls: Anticancer Agents Based on Allocolchicines

A new class of nitrovinyl biphenyl compounds based on the structures of colchicines and allocolchicines were designed, synthesized, and shown to inhibit tubulin polymerization and cause mitotic arrest. A majority of these compounds were found to possess potent anticancer properties, with IC50 values in the range of 0.05–7u2005μM, and are equally potent with colchicine in HeLa and MCF‐7 cells. Compounds 14u2009e and 14u2009f inhibited tubulin assembly by more than 60u2009%, and flow cytometry studies indicated growth arrest of cells in the G2/M phase of the cell cycle in a concentration‐dependent manner. Treatment of cells with 14u2009f resulted in upregulation of cyclinu2005B1 and aurora kinaseu2005B mRNA levels, corresponding to growth arrest in the G2/M phase of the cell cycle as the mode of action.

Design and synthesis of biaryl aryl stilbenes/ethylenes as antimicrotubule agents

Two new series of compounds E-2,3,4-trimethoxy-6-styrylbiphenyls and 2,3,4-trimethoxy-6-(1-phenylvinyl)biphenyls were designed, synthesized and evaluated for antitubulin activity. A common intermediate 4,5,6-trimethoxybiphenyl-2-carbaldehydes was employed to generate the two scaffolds. Majority of the analogs inhibited cell proliferation and those functionalized with 3,4-(1,3-dioxolane) and 3,4-difluoro groups were identified as effective inhibitors in both the series. Treatments with 19b, 19c, 22b and 22c arrested cells at G2/M phase, disrupted microtubule network, accumulated tubulin in the soluble fraction and manifested an increased expression of the G2/M marker, Cyclin B1. Molecular docking analysis demonstrated the interaction of these compounds at the colchicine binding site of tubulin.

Chemoselective one-pot synthesis of β-keto sulfones from ketones

A practical method to synthesize substituted β-keto sulfones directly from ketones at room temperature has been developed. This method involves the nucleophilic addition of a base generated enolate to sulfonyl iodide. The reaction shows high chemoselectivity for the addition of a sulfonyl group to an α-carbon over a hydroxyl group. In addition, the given protocol provides good to excellent yields of β-keto sulfones under mild reaction conditions. Moreover, the regiochemical aspect of the protocol is also explored.