Regioselective synthesis of novel 3-allyl-2-(substituted imino)- 4-phenyl-3H-thiazole and 2,2 0 -(1,3-phenylene)bis (3-substituted-2-imino-4-phenyl-3H-thiazole) derivatives as antibacterial agents Jafar Abbasi Shiran a , Asieh Yahyazadeh a,⇑ , Manouchehr Mamaghani a , Mehdi Rassa b a Department of Chemistry, Faculty of Sciences, University of Guilan, P.O. Box 1914, Rasht, Iran b Department of Biology, Faculty of Sciences, University of Guilan, P.O. Box 41335-1914, Rasht, Iran highlights " Synthesis of allyl-1,3-thiazoline and bis(1,3-thiazoline) have been studies. " Antibacterial activity of 3H-thiazole and bis(3H-thiazole) derivatives were measured. " Bis-structure indicated higher antibacterial activity compare to other compounds. article info Article history: Received 18 December 2012 Received in revised form 3 February 2013 Accepted 4 February 2013 Available online 14 February 2013 Keywords: Allylisothiocyanate Allylthiourea Allyl-3H-thiazole Bis-allyl-3H thiazole Antibacterial activity abstract Several novel 3-allyl-2-(substituted imino)-4-phenyl-3H-thiazole derivatives were synthesized by the reaction of allyl-thioureas and 2-bromoacetophenone. We also report the synthesis of bis-allyl-3H thia- zoles using the reaction of various isothiocyanates and 1,3-phenylenediamine. The structures of all com- pounds were characterized by spectral and elemental analysis. Most of the synthesized compounds exhibited efficient antibacterial activities against Salmonella enterica, Micrococcus luteus, Bacillus subtilis and Pseudomonas aeruginosa. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction Thiazoles and their derivatives exhibit various biological activ- ities such as anti-bacterial [1], anti-fungal [2], anti-inflammatory [3], anti-convulsant [4], pifithrin (pft-a), skin whitening agent (KHG22394) [5], Furthermore, some thiazoles are used in agricul- ture as pesticides and plant growth regulators [6]. Several novel thiazole derivatives have been reported in literatures such as; introduction of fluorine into thiazoline [7] and synthesis of sydno- nyl substituted thiazolidinone and thiazoline derivatives [8]. The above mentioned biological and synthetic significance of thiazole derivatives promoted us to carry out the synthesis of some new 3-allyl-2- imino-4-phenyl-3H-thiazoles. We felt that introduction of allyl groups into structure of 1,3-thiazolines can bring about sig- nificant changes in the physicochemical and biological attributes. Herein, we report a regioselective synthesis of new derivatives of 3-allyl-2-(substituted imino)-4-phenyl-3H-thiazole 2a-h (Scheme 1) and 2,2 0 -(1,3-phenylene)bis(3-substituted-2-imino-4-phenyl-3H- thiazole) 4a-c (Scheme 2) as antibacterial agents. 2. Experimental 2.1. Materials and methods All commercially available chemicals and reagents were used without further purification. Melting points were determined with an Electrothermal model 9100 apparatus and are uncorrected. FT- IR spectra were recorded on a Shimadzu 8400S spectrophotometer. The NMR spectra were recorded on a Bruker AVANCE DMX400 spectrometer, operating at 400 MHz ( 1 H NMR) and 100 MHz ( 13 C NMR). The chemical shift values are expressed in ppm relative to TMS as an internal standard. Elemental analyses were recorded with a CHN model 2400 Perkin–Elmer and agreed with the calcu- lated values. 0022-2860/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.molstruc.2013.02.003 ⇑ Corresponding author. Tel./fax: +98 1313233262. E-mail address: Yahyazadeh@guilan.ac.ir (A. Yahyazadeh). Journal of Molecular Structure 1039 (2013) 113–118 Contents lists available at SciVerse ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc