magnified image N,N′‐(1,4‐phenylene)bis(3‐oxo‐3‐phenylpropanamide) 1 reacts with DMFDMA in refluxing toluene to afford N,N′‐(1,4‐phenylene)bis(2‐benzoyl‐3‐(dimethylamino)acrylamide) 2. Compound 2 reacts with a twofold excess of the active methylene reagents 3a, 3b, 3c to afford the pent‐2‐enediamide derivatives 7 and 8a, 8b, respectively. Compounds 7 and 8a could be cyclized to afford the same compound N,N′‐(1,4‐phenylene)bis(5‐cyano‐6‐oxo‐2‐phenyl‐1,6‐dihydropyridine‐3‐carboxamide) 9a while 8b was cyclized to afford the 6‐thioxo analogue 9b. Compound 2 reacts with hydrazine derivatives 10a, 10b in refluxing ethanol/piperidine to afford the hydrazinylacrylamide derivatives 11a, 11b, which have been cyclized to the corresponding N,N′‐(1,4‐phenylene)bis(1H‐pyrazole‐4‐carboxamide) derivatives 12a, 12b, respectively. Compound 2 reacts also with urea derivatives 13a, 13b, 13c in refluxing ethanol/piperidine to afford the N,N′‐(1,4‐phenylene)bis(2‐benzoyl‐3‐substituted‐acrylamide) derivatives 14a‐c, which could be cyclized into N,N′‐(1,4‐phenylene)bis(6‐phenyl‐1,2‐dihydropyrimidine‐5‐carboxamide)‐2‐oxo; 2‐thioxo or 2‐imino derivatives 15a, 15b, 15c, respectively. J. Heterocyclic Chem., (2009).

The 5-(ethoxymethylene)-4-thioxothiazolidin-2-ones 2a-c were synthesized and reacted with acrylonitrile. ethyl acrylate. ß-nitrostyrene. N-phenylmaleimide and malononitrile under different conditions. to yield the cycloaddition products 3-14. The antibacterial and antifungal activities of the new products were tested.Reaktionen mit 5-Ethoxymethylenthiazolidin-2,4-dion-Derivaten und ihre biologische Wirksamkeit Die 5-Ethoxymethylen-4-thioxo-2-one 2a-c wurden synthetisiert und mit Acrylnitril, Ethylacrylat. ß-Nitrostyrol. N-Phenylmaleinsäureimid und Malonodinitril unter verschiedenen Bedingungen umgesetzt. Die Wirkungen der neuen Verbindungen gegen Bakterien und Pilze wurde geprüft.As apart of our studies directed towards the synthesis of new compounds of biological potentialities, comaining thiopyrano-thiazole ring system 1-)1, we report here the results of cycloaddition of some dienophiles with the ethoxymethylene derivatives of 4-thioxo-thiazolidine-2-ones.The 5-ethoxymethylene derivatives 2a-c were synthesized by the reaction of 2-thiazolidinone-4-thiones la-c with ethylorthoformate in acetic anhydride.Treatment of the coloured 2a-c with acrylonitrile in toluene at room tempo afforded the colourless 1: 1 adducts 3a-c. Structure 3 was established from elemental and IR data. Besides, the 1 H -NMR data of 3c can be interpreted in terms of 6-cyano-3-phenyl-7 -ethoxy-5,6-dihydrothiopyranoI2,3-dl-thiazolidin-2-one. The formation of the adduct 3c is a conclusive evidence for 2 + 4 cycloaddition rather than N-cyanoethylation re action represented by structure 4.On the other hand, when the above re action was carried out in refluxing acetic acid, 5a-c were obtained via ethoxy group elimination. Similar ethoxy group elimination has been reported by acid treatment 4l . Moreover. when 3a-c were refluxed in acetic acid, 5a-c were obtained.

in Wiley InterScience (www.interscience.wiley.com).2-(1-Aryl-ethylidene)-malononitriles 1a-d undergo self dimerization in ethanol catalyzed by sodium ethoxide to afford 2-[4,6-diaryl-3-cyano-6-methyl-5,6-dihydropyridin-2(1H)-ylidene]-malononitrile derivatives 3a-d, respectively. The structure of the dimer was elucidated by X-ray crystallography and a plausible mechanism for its formation is depicted. Compound 3a couples with arene diazonium salts 4a-d to afford the hydrazo derivatives 5a-d; and reacts with hydrazine hydrate and phenylhydrazine 6a,b to afford the pyrazolo [3,4-h]

5‐Arylidene‐2‐thiazolidinone‐4‐thiones 1 undergo Michael type reactions with Ω‐nitrostyrene, α,β‐unsaturated ketones and N‐arylmaleimides to give the corresponding 7‐aryl‐tetrahydro‐7H‐thiopyrano[2,3‐d]thiazole‐2‐one derivatives 3 and 4. Arylmagnesium bromides add to the lateral double bond of 5‐arylidene‐3‐phenyl‐2‐thiazolidinone‐4‐thiones 5 to yield products 6. With phenyl‐hydrazine at room temperature, 1 or 5 yield the corresponding aldehyde phenylhydrazones and 4‐phenyl‐hydrazono‐2‐thiazolidinone or its 3‐phenyl derivative. The thione group in 5‐diaryl‐methyl‐2‐thiazolidinone‐4‐thiones condenses with phenylhydrazine to yield 5‐diarylmethyl‐4‐phenyl‐hydrazono‐2‐thiazolidinones 9.

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