Sridhar Madabhushi

Oxyhalogenation of thiols and disulfides into sulfonyl chlorides/bromides using oxone-KX (X = Cl or Br) in water

A simple and rapid method for efficient synthesis of sulfonyl chlorides/bromides by oxyhalogenation of thiols and disulfides with oxone-KX (X = Cl or Br) using water as the solvent is described.

Synthesis of novel benzimidazole functionalized chiral thioureas and evaluation of their antibacterial and anticancer activities.

A small library of benzimidazole functionalized chiral thioureas was prepared starting from natural amino acids (S)-alanine, (S)-phenylalanine, (S)-valine and (S)-leucine and also their (R)-isomers and studied their antimicrobial activity against a various Gram-positive and Gram-negative bacterial strains. In this study, compounds 5g and 5j were found to exhibit good antibacterial activity against both Gram-positive and Gram-negative bacterial strains such as Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Klebsiella planticola, Escherichia coli and Pseudomonas aeruginosa. In the cytotoxicity study, thioureas derived from non-natural amino acids 5a-l showed good activity against human cancer cell lines A549, MCF7, DU145, HeLa, and no cytotoxicity was observed with their antipodes 6a-l.

Efficient synthesis of polyfunctionalized thiophene-2,3-diones and thiophen-3(2H)-ones using β-oxodithioesters

Efficient methods for the preparation of polyfunctionalized thiophene-2,3-diones and thiophen-3(2H)-ones using β-oxodithioesters were described. In this study, β-oxodithioesters were found to react directly with oxalyl chloride producing 4-aroyl-5-(methylthio)thiophene-2,3-diones in 96–98% yields. However, β-oxodithioesters were found to react efficiently with chloroacetic anhydride in the presence of a base catalyst such as DMAP, which gave 4-aroyl-5-(methylthio)thiophen-3(2H)-ones in 61–77% yields.

New method for the preparation of N-chloroamines by oxidative N-halogenation of amines using oxone-KCl

ABSTRACT A mild and efficient method for preparation of N-chloroamines by oxidative N-halogenation of primary/secondary amines using oxone-KCl is described. GRAPHICAL ABSTRACT

Oxone-mediated annulation of 2-aminobenzamides and 1,2-diaminobenzenes with sec-amines via imine-N-oxides: new syntheses of 2,3-dihydroquinazolin-4(1H)-ones and 1H-benzimidazoles

An efficient and mild method for the preparation of 2,3-dihydroquinazolin-4(1H)-ones and 1H-benzimidazoles by the oxone-mediated reaction of sec-amines via imine-N-oxides with 2-amino-N-substituted benzamides and 1,2-diaminobenzenes respectively in THF–water (2 : 1) at ambient temperature is described.

Efficient multicomponent synthesis of spiro[indoline-3,4′-thiopyran]-2-ones

ABSTRACT Synthesis of new thiopyran fused spirooxindoles (spiro[indoline-3,4′-thiopyran]-2-ones) were achieved by a multicomponent reaction of N-methyl isatin, malononitrile/ethyl cyanoacetate, and β-oxodithioester using N,N′-dimethylaminopyridine as the catalyst. GRAPHICAL ABSTRACT

Synthesis of polysubstituted 3,4-dihydro-2H-thiopyrans by regioselective annulation of 3,3-disubstituted allylic alcohols with a β-oxodithioester

Polyfunctionalized 3,4-dihydro-2H-thiopyrans were obtained in high yields via the regioselective annulation of 3,3-disubstituted allylic alcohols with a β-oxodithioester under BF3·Et2O catalysis.

Synthesis and characterization of 2-(4-((1-alkyl or aryl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)naphtho[1,2-d]oxazoles for protein tyrosine phosphatase 1B inhibitory activity

Abstract2-(4-((1-Alkyl/aryl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)naphtho[1,2-d] were prepared and evaluated as protein tyrosine phosphatase 1B (PTP1B) inhibitors. In this study, two new compounds with potent PTP1B inhibitory activity were identified.