Novel p-arylthio cinnamides as antagonists of leukocyte function-associated antigen-1/intracellular adhesion molecule-1 interaction. 2. Mechanism of inhibition and structure-based improvement of pharmaceutical properties

Catalyst-free chemoselective α-sulfenylation/β-thiolation for α,β-unsaturated carbonyl compounds

A novel, efficient, catalyst-free and product-controllable strategy has been developed for the chemoselective α-sulfenylation/β-thiolation of α,β-unsaturated carbonyl compounds. An aromatic sulfur group could be chemoselectively introduced at α- or β-position of carbonyls with different sulfur reagents under slightly changed reaction conditions. A series of desired products were obtained in moderate to excellent yields. Mechanistic studies revealed that B2pin2 played the key role in activating the transformation towards the β-thiolation of α,β-unsaturated carbonyl compounds. This transition-metal-catalyst-free method provides a convenient and efficient tool for the highly chemoselective preparation of α-thiolation or β-sulfenylation products of α,β-unsaturated carbonyl compounds.

Cinnamamide: An insight into the pharmacological advances and structure-activity relationships

The cinnamamide (cinnamic acid amide and cinnamide) is a privileged scaffold present widely in a number of natural products. The scaffold acts as a useful template for designing and arriving at newly drug-like molecules with potential pharmacological activity. An attempt has been made to review the extensive occurrence of cinnamamide scaffold in many lead compounds reported for treating various diseases, their binding interactions with the therapeutic targets as well as mechanism of action and their structure-activity relationships. The discoveries of cinnamamide systems and some examples of unusual cinnamamides having an aromatic, aliphatic, and heterocyclic or other rings condensed to the basic cinnamamide structure also have been extensively covered in this review.

An efficient clean methodology for the C–S coupling to aryl thioethers and S–S homocoupling to aromatic disulfides catalyzed over a Ce(iv)-leucine complex immobilized on mesoporous MCM-41

Anchored Ce(iv) on the surface of MCM-41 mesoporous silica was used for the synthesis of aryl thioethers and aromatic disulfides.

Substrate-switched dual functionalization of alkenes: catalyst-free synthetic route for β-hydroxy and β-keto thioethers

A substrate-controlled dual functionalization of alkenes under catalyst-free and solvent-free conditions to provide β-hydroxy thioethers and β-keto thioethers is described.

Site-Selective C-S Bond Formation at C-Br over C-OTf and C-Cl Enabled by an Air-Stable, Easily Recoverable, and Recyclable Palladium(I) Catalyst

This report widens the repertoire of emerging PdI catalysis to carbon-heteroatom, that is, C-S bond formation. While Pd0 -catalyzed protocols may suffer from the formation of poisonous sulfide-bound off-cycle intermediates and lack of selectivity, the mechanistically diverse PdI catalysis concept circumvents these challenges and allows for C-S bond formation (S-aryl and S-alkyl) of a wide range of aryl halides. Site-selective thiolations of C-Br sites in the presence of C-Cl and C-OTf were achieved in a general and a priori predictable fashion. Computational, spectroscopic, X-ray, and reactivity data support dinuclear PdI catalysis to be operative. Contrary to air-sensitive Pd0 , the active PdI species was easily recovered in the open atmosphere and subjected to multiple rounds of recycling.

Synthesis of DNA interactive C3-trans-cinnamide linked β-carboline conjugates as potential cytotoxic and DNA topoisomerase I inhibitors

A series of new C3-trans-cinnamide linked β-carboline conjugates has been synthesized by coupling between various β-carboline amines and substituted cinnamic acids. Evaluation of their anti-proliferative activity against a panel of selected human cancer cell lines such as A549 (lung cancer), MCF-7 (breast cancer), B16 (melanoma), HeLa (cervical cancer) and a normal cell line NIH3T3 (mouse embryonic fibroblast cell line), suggested that the newly designed conjugates are considerably active against all the tested cancer cell lines with IC₅₀ values 13-45 nM. Moreover, the conjugates 8v and 8x were the most active against MCF-7 cells (14.05 nM and 13.84 nM respectively) and also even potent on other cell lines tested. Further, detailed investigations such as cell cycle analysis, apoptosis induction study, topoisomerase I inhibition assay, DNA binding affinity and docking studies revealed that these new conjugates are DNA interactive topoisomerase I inhibitors.

A Convenient Synthesis of a Lymphocyte Function-Associated Antigen-1 (LFA-1) Antagonist of ‘Compound 4’

The lymphocyte function-associated antigen-1 (LFA-1) antagonist of ‘Compound 4’ was synthesised by a convenient route using cheap, commercially available starting materials and catalysts under mild reaction conditions and by easily handled reactions. The total yield in the preparation of ‘Compound 4’ was more than 38% via Sonogashira coupling of an iodide and an alkyne, reduction of the alkyne catalysed by Raney nickel and later steps involving hydrolysis of an ester, condensation of an acid and an amine and a final hydrolysis of an ester.

Diels-Alder and Stille Coupling Approach for the Short Protecting-Group-Free Synthesis of Mycophenolic Acid, Its Phenylsulfenyl and Phenylselenyl Analogues, and Reactive Oxygen Species (ROS) Probing Capacity in Water

A short, protecting-group-free synthesis is achieved. The synthesis is step-efficient and general. A Diels-Alder and Stille cross-coupling approach includes key transformations, allowing for a competitive synthesis which involves a rare halophenol Stille cross-coupling study. The phenylselenyl and phenylsulfenyl analogues were prepared as novel compounds in good overall yield. The applicability of one of the intermediates as a potential probe for reactive oxygen species (ROS) in water is investigated.

Efficient dehydrative alkylation of thiols with alcohols catalyzed by alkyl halides

Alcohols can be efficiently converted into the useful thioethers by a transition metal- and base-free dehydrative S-alkylation reaction with thiols or disulfides by employing alkyl halides as the effective catalyst. This simple and efficient method is a green and practical way for the preparation of thioethers, as it tolerates a wide range of substrates such as aryl and alkyl thiols, as well as benzylic, allylic, secondary, tertiary, and even the less reactive aliphatic alcohols.

Cobalt-catalyzed carbon–sulfur/selenium bond formation: synthesis of benzo[b]thio/selenophene-fused imidazo[1,2-a]pyridines

An efficient cobalt-catalyzed C–S/C–Se bond formation method for the synthesis of benzo[b]thio/selenophene-fused imidazo[1,2-a]pyridines has been developed.

Recyclable imidazolium ion-tagged nickel catalyst for microwave-assisted C–S cross-coupling in water using sulfonyl hydrazide as the sulfur source

Recyclable nickel(ii) catalyst promoted sulfenylation of aryl halides with sulfonyl hydrazides in water using microwave irradiation under mild conditions is reported.

Copper Mediated Coupling of 2-(Piperazine)-pyrimidine Iodides with Aryl Thiols using Cu(I)Thiophene-2-carboxylate

A copper-mediated synthesis of diaryl sulfides utilizing Cu(I)-thiophene-2-carboxylate (CuTC) is described. We demonstrate the use of CuTC as a soluble, non-basic catalyst in the coupling of aryl iodides and aryl thiols in the synthesis of synthetically advanced diaryl sulfides. This method allows for the successful coupling of challenging substrates including ortho-substituted and heteroaryl iodides and thiols. Additionally, most of the aryl iodide substrates used here contain the privileged piperazine scaffold bound to a pyrimidine, pyridine, or phenyl ring and thus this method allows for the elaboration of complex piperazine scaffolds into molecules of biological interest. The method described here enables the incorporation of late-stage structural diversity into diaryl sulfides containing the piperazine ring, thus enhancing the number and nature of derivatives available for SAR investigation.

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C-S cross-coupling reaction

The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols using nickel nanoparticles (Ni NPs) supported on reduced graphene oxide (Ni/RGO) as a heterogeneous catalyst. It is observed that the uniformly dispersed Ni NPs supported on RGO could exhibit excellent catalytic activity in C–S cross-coupling reactions and the catalytic application is generalized with diverse coupling partners. Although the electron-rich planar RGO surface helps in stabilizing the agglomeration-free Ni NPs, the catalytic process is found to occur involving Ni(II) species and the recovered catalyst containing both Ni(0)/Ni(II) species is equally efficient in recycle runs. A correlation of loading of Ni species, size of NPs and the intermediate Ni-related heterostructures formed during the catalytic process has been established for the first time, and found to be best in the C–S cross-coupling reaction for Ni(0) and Ni(II) NPs of the average sizes 11–12 nm and 4 nm, respectively.