A catalyst-free multicomponent domino sequence for the diastereoselective synthesis of (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]chromen-4-ones.

The three-component domino reactions of (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones, 3-formylchromone and anilines under catalyst-free conditions afforded a library of novel (E)-3-(2-arylcarbonyl-3-(arylamino)allyl)-4H-chromen-4-ones in good to excellent yields and in a diastereoselective transformation. This transformation generates one C-C and one C-N bond and presumably proceeds via a reaction sequence comprising a Michael-type addition-elimination reaction, a nucleophilic attack of an enamine to a carbonyl reminiscent of one of the steps of the Bayllis-Hilman condensation, and a final deoxygenation. The deoxygenation is assumed to be induced by carbon monoxide resulting from the thermal decomposition of the dimethylformamide solvent.

A regio- and stereoselective 1,3-dipolar cycloaddition for the synthesis of novel spiro-pyrrolothiazolyloxindoles and their antitubercular evaluation.

The 1,3-dipolar cycloaddition of azomethine ylides derived from substituted isatins and 1,3-thiazolane-4-carboxylic acid to a series of 2-(arylmethylene)-2,3-dihydro-1H-inden-1-ones afforded twenty nine novel spiro-pyrrolothiazolyloxindoles regio- and stereoselectively in moderate yields. These compounds were screened for their in vitro activity against Mycobacterium tuberculosis H37Rv (MTB) using agar dilution method. Among 29 compounds screened, spiro[5.3']-5'-nitrooxindole-spiro-[6.3″]-2,3-dihydro-1H-inden-1″-one-7-(2,3-dichlorophenyl)tetrahydro-1H-pyrrolo[1,2-c][1,3]thiazole, was found to be the most active compound with MIC of 2.8 µM against MTB, being 1.67 and 2.70 times more active than ciprofloxacin and ethambutol respectively.