Thia-Michael Reaction under Heterogeneous Catalysis

Thia-Michael reactions between aliphatic and aromatic thiols and various Michael acceptors were performed under environmentally-friendly solvent-free conditions using Amberlyst® A21 as a recyclable heterogeneous catalyst to efficiently obtain the corresponding adducts in high yields. Ethyl acrylate was the main acceptor used, although others such as acrylamide, linear, and cyclic enones were also utilized successfully. Bifunctional Michael donor, 3-mercaptopropanoic acid, positively furnished the product, albeit in a lower yield and after leaving the reaction to take place for a longer time. The catalyst was easy and safe to handle and successfully recycled for five consecutive cycles.

Novel p-Functionalized Chromen-4-on-3-yl Chalcones Bearing Astonishing Boronic Acid Moiety as MDM2 Inhibitor: Synthesis, Cytotoxic Evaluation and Simulation Studies

BACKGROUND

Novel 4-[3-(6/7/8-Substituted 4-Oxo-4H-chromen-3-yl)acryloyl]phenylboronic acid derivatives (5a-h) as well as other 6/7/8-substituted-3-(3-oxo-3-(4-substitutedphenyl) prop-1-enyl)-4H-chromen-4-one derivatives (3a-u) have been designed as p53-MDM2 pathway inhibitors and reported to possess significant cytotoxic properties against several cancer cell lines.

OBJECTIVES

The current project aims to frame the structure-anticancer activity relationship of chromen-4-on-3-yl chalcones (3a-u/5a-h). In addition, docking studies were performed on these chromeno-chalcones in order to have an insight into their interaction possibilities with MDM2 protein.

METHODS

Twenty-nine chromen-4-on-3-yl chalcone derivatives (3a-u/5a-h) were prepared by utilizing silica supported-HClO4 (green route with magnificent yield) and tested against four cancer cell lines (HCT116, MCF-7, THP-1, NCIH322).

RESULTS

Among the series 3a-u, compound 3b exhibited the highest anticancer activity (with IC50 values ranging from 8.6 to 28.4 µM) overall against tested cancer cell lines. Interestingly, para- Boronic acid derivative (5b) showed selective inhibition against colon cancer cell line, HCT-116 with an IC50 value of 2.35 µM. Besides the emblematic hydrophobic interactions of MDM2 inhibitors, derivative 5b was found to exhibit extra hydrogen bonding with GLN59 and GLN72 residues of MDM2 in molecular dynamics (MD) simulation. All the compounds were virtually nontoxic against normal fibroblast cells.

CONCLUSION

Novel compounds were obtained with good anticancer activity especially 6- Chlorochromen-4-one substituted boronic acid derivative 5b. The molecular docking study proposed good activity as a MDM-2 inhibitor suggesting hydrophobic as well as hydrogen bonding interactions with MDM2.

Thio-Michael addition of α,β-unsaturated amides catalyzed by Nmm-based ionic liquids

Most substrates work well for this transformation in water, and the IL-catalyst is recyclable and applicable for gram-scale synthesis.

One-pot odorless thia-Michael reaction by copper ferrite nanoparticle-catalyzed reaction of elemental sulfur, aryl halides and electron-deficient alkenes

One-pot CuFe₂O₄ catalyzed reaction of aryl halides or boronic acids with sulfur and electron-deficient alkenes for generation of sulfides.

N-heterocyclic carbene catalyzed carba-, sulfa-, and phospha-Michael additions with NHC·CO₂ adducts as precatalysts

N-heterocyclic carbene catalyzed Michael additions have been revisited with 1,3-dialkyl- or 1,3-diarylimidazol(in)ium-2-carboxylates, that is, NHC·CO2 adducts, as the source of the free NHC catalysts in solution. Using these precatalysts, a number of efficient carba-, sulfa-, and phospha-Michael additions were achieved very conveniently, without the need for an external strong base to generate the NHC by deprotonation of an azolium salt. To further expand the scope of the procedure, some NHC-catalyzed sulfa-Michael/aldol organocascades were also investigated.

Total synthesis of grandisine D

Total synthesis of grandisine D (5) was achieved by a Brønsted acid mediated Morita-Baylis-Hillman (MBH) ring-closure reaction and stereoselective aldol condensation with (S)-5-methylcyclohexenone (9) as key steps. The MBH approach was also applicable for the construction of the aza-fused bicyclic systems of pyrrolizidine and stemona alkaloids.