The hitherto unknown 5‐(2‐aryl‐2‐oxoethyl)‐4‐oxo‐1,3‐thiazolidines 1a‐l have been synthesized viacycloaddition process between thiourea and/or its derivatives with 3‐aroylpropenoic acids. 1H NMR spectra revealed the presence of 1a‐c as a tautmeric mixture. The presence of the thiazoline tautmers (1a‐c)′ was confirmed by methylating the tautmeric mixture, to the respective methylated derivatives 2‐N‐methylanilino‐5‐(2‐aryl‐2‐oxoethyl)‐4‐oxo‐1,3‐thiazolines2a‐c and 1g‐i. Acidic treatment of 1 provided the respective 2‐oxo homologues 3a‐i. When 1a‐d, k were refluxed with DMF, molecular rearrangement was achieved, providing the 4‐oxo‐2‐thioxoimidazolidine isomers4a‐d, k. Bromination of 4a and 4d in hot acetic acid afforded the respective (E,Z)‐5‐benzoylmethylene derivatives 5a,d which were prepared authentically. Thiation of 1a‐c and 4a‐c gave 5‐aryl‐2,3‐dihydro‐2‐phenyliminothieno[2,3‐d]thiazoles 6a‐cand 1‐phenyl‐5‐aryl‐2,3‐dihydro‐2‐thioxothieno[2,3‐d]imidazoles 7a‐c, respectively. The proposed structures have been confirmed by elemental analysis and spectroscopic data. The selected products showed different antimicrobial effect.

Novel (E)-3-(benzo[d][1,3]dioxol-5-yl)-2-cyanoacryloyl chloride 4 was condensed with several mono-; 1,2-; 1,3- and 1,4-bi-nucleophilic reagents containing nitrogen and oxygen to give new 2-propenoylamide and ester derivatives. Some of these amides cyclised under the reaction conditions and/or with POCl3 to give new derivatives of heterocyclic systems. Antibacterial activities were tested for nine of these products.

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A One-Pot Synthesis of 2,3-Dihydro-2-thioxothieno[2,3-d]thiazoles.-A mild and simple one-pot synthesis leads to thioxothienothiazoles (II) in excellent yields by reaction of thiazolidines (I) with either Lawesson's reagent or tetraphosphorous decasulfide. However, thionation of the E/Z mixtures (III) affords the corresponding title compounds (IIc) and (IId) in lower yields together with unknown oily compounds. The new method provides an easy route to the fused bithienyls (IIa) and (IIb) of anticipated nematocidal activity. The route of conversion is discussed. -(OMAR, MOHAMED T.; EL-AASAR, NADIA K.; SAIED, KHALED F.; Synthesis (2001) 3, 413-418; Dep. Chem., Fac. Sci., Ain-Shams Univ., Cairo, Egypt; EN)