Unexpected Synthesis of Novel 3-Allyl-5-(arylidene)-2-thioxo-thiazolidin-4-ones in Reactions of 3-Allylrhodanine with 2-Arylidene-4-methyl-5-oxopyrazolidinium Ylides

The reaction of 3-allylrhodanine with 2-arylidene-4-methyl-5-oxopyrazolidinium ylides proceeded unexpectedly to form novel 3-allyl-5-(arylidene)-2-thioxo-thiazolidin-4-ones 6a–k in good yields. All structures have been formulated on the basis of their spectral (IR, NMR, MS) data and elemental analyses. In addition, the structure of compound 6a was confirmed by means of x-ray crystallographic analysis.