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An acid-catalyzed regioselective cyclization reaction of 2,5-disubstituted-1,3,4-thiadiazoles and 1,3,4-oxadiazoles has been developed. The synthetic precursors alkyl 2-(methylthio)-2-thioxoacetates/alkyl 2-amino-2-thioxoacetates react efficiently with acyl hydrazides, which transformed into a series of dehydrative and desulfurative products with employment of p-TSA and AcOH through a regioselective cyclization process. The alkyl 2-amino-2-thioxoacetate pathway generates excellent yield among the mentioned procedures. The reported methods are operationally simplistic and highly efficient with metal-free conditions and demonstrate significant functional group compatibility. Regioselective cyclized products were confirmed by single-crystal X-ray diffraction studies.

Design of chemically novel, biologically potent small heterocyclic molecules with anticancer activities, which targets the enzyme heparanase has gained prominent clinical interest. We have synthesized a novel class of carboxamide derivatives by coupling various substituted aromatic acid hydrazides and triazoleamine with pyrrolidine carboxylic acid by using coupling agents. The synthesized compounds are characterized by spectroscopic techniques such as FT-IR, HRMS and NMR. These compounds are investigated for cytotoxicity on different cancer cell lines and heparanase inhibitory activity. Most of them showed moderate heparanase inhibitory activity and good cytotoxicity.

Synthesis of a series of 2-(arylmethylthio)-6-ethyl-7H-pyrrolo[2,3-d]pyrimidin-4-ol and their cytotoxic activity on HCT-116 and A-549 cell lines using MTT assay is reported. The 6-ethyl-2-((4-fluorobenzyl)thio)-7H-pyrrolo[2,3-d]pyrimidin-4-ol 3dis the most active compound on HCT-116 with IC50of 8.65 ± 0.36 µM. On the other hand, 6-ethyl-2-((3-nitrobenzyl)thio)-7H-pyrrolo[2,3-d]pyrimidin-4-ol 3iand 2-((2-bromo‑3,4-dimethoxybenzyl)thio)-6-ethyl-7H-pyrrolo[2,3-d]pyrimidin-4-ol 3jexhibited high activities on A-549 with IC50values 2.7 ± 0.49 µM and 2.21 ± 0.66 µM respectively.

In this review, we present recent advances in the transition metal catalyzed electro-organic transformations since 2000. The review mainly focuses on C-C and C-heteroatom bond-forming reactions along with miscellaneous reactions. Electro-organic synthesis attracts the attention of chemists due to no use of equivalent amount of chemical oxidants. Since electron is a mass free reagent, atom economy of electro-organic reactions is high and hence they are green reactions. We present articles in which transition metal catalysts are regenerated by electricity. Besides, reactions due to sacrificial anodes are also presented.

Propylphosphonic anhydride (T3P®)–DMSO-mediated one-pot three-component synthesis which provides 2-arylquinolines in a single step from benzyl alcohols, anilines, and ethyl vinyl ether by the modified Povarov reaction has been demonstrated. T3P®–DMSO is a mild and low-toxic peptide coupling agent and an easy to handle reagent for bulk reactions at room temperature.

An efficient and ecofriendly protocol for the N-alkylation of secondary heterocyclic amines such as 10H-phenothiazine, 5H-dibenzo[b,f]azepine, 9H-carbazole and 2-butyl-4-chloro-1H-imidazole-5-carbaldehyde by various alkyl halides such as allyl bromide, propargyl bromide, methyl iodide and 4-methylbenzyl chloride in Glucose-Urea-NaCl and Glucose-Urea-NH4Cl eutectic mixture has been reported. High yield (73-94%) and short reaction time are the noteworthy features of this protocol.

Reductive coupling of o-substituted carbonyl compounds and m-substituted carbonyl compounds by the direct transfer of electron to carbonyl group respectively gave 1-(4-(1-hydroxy-1-phenylethyl/methyl)phenyl)ethanones/methanones and 2,3-bis(3-substitutedphenyl)butane/ethane-2,3-diols. 4-Methoxyacetophenone surprisingly gave 4-methoxybenzoic acid as oxidation product. Even acetophenone conjugated with alkyne group afforded interesting reductive addition product. Finally, imine also furnished reductively coupled diamino compound. Probable mechanisms for the formation of products is proposed.