A series of 4-[4-(2, 4-dichloro-5-fluorophenyl)-6-(4-methoxyphenyl)pyrimidine-2-yl]-1-(arylaminocarbonyl/thiocarbonyl)semicarbazides was synthesized and their in vitro antibacterial activity was studied.In recent decades, the problems of multi-drug resistant microorganisms have reached alarming level in many countries around the world. Recent clinical reports published in the United State and European countries make an emphasis on increasing occurrence of meticillin-resistant S. aureus and other antibiotic-resistant human pathogenic microorganisms. Infections caused by those microorganisms pose a serious challenge to the medical community and need for an effective therapy has stimulated a search for novel antimicrobial agents. Chalcones are a class of privileged structure that have a wide range of biological properties [1] including anticancer [2], antimalarial [3 -4], antiviral [5], and antibacterial activities [6].Pyrimidine scaffold and its derivatives being components of a number of drugs are responsible for their biological, pharmaceutical and therapeutic activity [7]. Pyrimidine derivatives are attractive due to their pharmacological activity [8 -9] and possess antiviral [10], antitumor [11], antibacterial [12 -13], antihypertensive [14], and antituberculous properties [15]. Diaryl pyrimidine (DAPY'S) appears to be most effective against a wild type and various mutant strains of . In this work, we report the results of synthesis and biological assessment of some substituted pyrimidine derivatives. EXPERIMENTAL CHEMICAL PARTAll the reagents were of analytical grade and used directly. Melting points were determined in the open glass capillary and were uncorrected. Progress of the reaction was monitored by thin layer chromatography (TLC) using silica gel-G coated aluminum plates (0.5 mm thickness, Merck). Spots were visualized under UV radiation. All the components were purified by crystallization. Elemental analyses were carried out on PERKIN ELMER 2400. The IR spectra were recorded on BRUKER TENSOR Series using KBr pellets. 1 H NMR spectra were recorded on 300 MHz BRUKER ULTRASHIELD using DMSO-d 6 as a solvent and TMS as an internal reference and chemical shift values were expressed in d ppm. Table 1 and Table 2 present physicochemical and spectral data, respectively. 1-(2,4-Dichloro-5-fluorophenyl)-3-(4-methoxyphenyl)-2-propen-1-one (III).To a well stirred solution of 2,4-dichloro-5-fluoroacetophenone I (10.0 g, 0.048 mol) and 4-methoxybenzaldehyde II (6.53 g, 0.048 mol) in methanol (50 ml) 20% NaOH solution (10 ml) was added. The reaction mixture was stirred for 30 min at room temperature and left overnight. The progress of the reaction was monitored by TLC using toluene: acetone (8:2) as eluent. After completion of the reaction the mixture obtained was poured into ice-cold water, acidified, filtered and crystallized from ethanol to give III. Yield 70% (m.p. 120 -122°C). 2-Amino-4-(2,4-dichloro-5-fluorophenyl)-6-(4-methoxyphenyl)-pyrimidine (IV).A mixture of III (8.0 g, 0.024 mol), guanidine nitrate (4.39 ...

A series of urea and thiourea derivatives of s-triazine have been developed based on high yielding nucleophilic substitution of 2,4,6-trichloro-1,3,5-triazine by 4-hydroxy coumarin, cyclopropylamine and ammonia at suitable conditions. These were further treated with various substituted aryl isocyanate and aryl isothiocyanate. All the synthesized compounds were evaluated for their antibacterial activities against various Gram-positive and Gram-negative strains of bacteria. A few compounds showed good to superior in vitro antibacterial activity against S.aureus, B.subtilis, E.coli and P.aeruginosa respectively. The new synthesized compounds were characterized using IR, 1 H-NMR and elemental analysis.

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