Studies on Chemotherapeutics for Mycobacterium tuberculosis. XI

Synthesis and Antibacterial Activity of 4-Thiazolidone Derivatives containing the α, β-Unsaturated Ketone Group. (1)

Abstract

Condensation of the active methylene group at 5-position of 4-thiazolidone derivatives with aromatic aldehydes results in the formation of 5-arylidene-4-thiazolidones. These substances contain α, β-unsaturated ketonic bonding, =C=C-C=O, in their molecule so that they should react with the SH-system enzymes requisite for bacterial metabolism and may inhibit the growth of bacteria. Under such expectations, 2-thlo-, -oxo-, or -imino-5-arylidene-4-thiazolidones were prepared and were submitted to in vitro screening for tubercle bacilli. Of these compounds tested, 2-oxo derivatives showed the most powerful action, followed by the 2-thio derivatives, while 2-imino derivatives showed a much weaker action than the foregoing two. The effect of hydroxyl and nitro groups as a substituent in the benzene ring and the position thereof on the antibacterial action did not follow any definite order. The compounds already appearing in the existing literature were prepared as described and the unknown substances were prepared in a good yield by the condensation of 4-thiazolidones with aromatic aldehydes in acetic acid with the use of sodium acetate or in dilute sodium hydroxide solution with the addition of ammonium chloride.