A facile 1,3-dipolar cycloaddition of azomethine ylides to 2-arylidene-1,3-indanediones: Synthesis of dispiro-oxindolylpyrrolothiazoles and their antimycobacterial evaluation

A facile 1,3-dipolar cycloaddition of azomethine ylide generated in situ from the reaction of 1,3-thiazolane-4-carboxylic acid and isatin to 2-arylidene-1,3-indanediones furnished novel dispiro-oxindolylpyrrolothiazoles regio- and stereo-selectively in moderate to good yields (60-92%). In vitro antitubercular screening of 27 compounds against Mycobacterium tuberculosis H37Rv (MTB) disclosed that spiro[5.3']-5'-nitrooxindolespiro-[6.3 '']-1H-inden-1 '',3 ''(2H)-dione-7-(4-bromophenyl)tetrahydro-1H-pyrrolo[1,2-c] [1,3] thiazole has the maximum potency with a minimum inhibitory concentration (MIC) of 1.4 mu M against MTB, being 3.4 and 5.4 times more potent than ciprofloxacin and ethambutol, respectively. (C) 2010 Elsevier Ltd. All rights reserved.