Original Article 1-(SUBSITUTED)-4, 4, 6-TRIMETHYL-3, 4-DIHYDROPYRIMIDINE-2(1H)-THIONE: GREEN SYNTHESIS, ANTIBACTERIAL ACTIVITY AND DNA PHOTOCLEAVAGE ACTIVITY AJAY SHARMA a , RAJSHREE KHARE A* , VINOD KUMAR a , GIRISH KUMAR GUPTA b , VIKAS BENIWAL c a Department of Chemistry, Maharishi Markandeshwar University, Mullana, Ambala 133207, Haryana, India, b Department of Pharmaceutical Chemistry, Maharishi Markandeshwar College of Pharmacy, Maharishi Markandeshwar University, Mullana, Ambala 133207, Haryana, India, c Department of Biotechnology, Maharishi Markandeshwar University, Mullana, Ambala 133207, Haryana, India. Email: rajshreekhare@gmail.com Received: 10 Feb 2014, Revised and Accepted: 28 Apr 2014 ABSTRACT Objective: 1-(subsituted)-4,4,6-trimethyl-3,4-dihydropyrimidine-2(1H)-thione: Green synthesis, antibacterial activity and DNA photocleavage activity. Methods: In the present study, 1-(subsituted)-4,4,6-trimethyl-3,4-dihydropyrimidine-2(1H)-thione has been achieved under mild reaction conditions by employing microwave assisted and grind stone method. All the synthesized compounds were evaluated for their DNA nicking activity. Some of them were selected as to evaluate their antibacterial effect against gram- positive (Enterococcus) and gram-negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) bacteria. The outcome of the study indicating that compounds containing flour, methoxy and chloro substituent were found to exhibit complete DNA cleavage at 40 μg/μl concentration. Results: The reported compounds synthesized through greener methods such as grindstone and microwave assisted synthesis. Conclusion: Some of the compounds have exhibited promising antibacterial and DNA Photoclevage activity. Keywords: 2-Thiopyrimidine, Microwave assisted synthesis, Grindstone method, Antibacterial activity, DNA cleavage activity. INTRODUCTION Pyrimidine derivatives are extensively investigated due to their great biological significance and the main constituent of nucleic acids. They found to exhibit remarkable pharmacological activities [1-3] such as anti-cancer [4,5], anti-tumor [6,7], anti-inflammatory [8] and antifungal [9] etc. They are also widely used as agrochemical, pharmaceuticals, dyes [10], organic additives in electroplating of steel [11] and in the polymerization process [12]. A literature survey reveals that DNA is the primary target receptor of most anticancer and antitumor drugs [13-15]. DNA of cancer cells can be damaged as a result of interaction with small molecules, which in turn blocks the cell division and finally cause the death of cancer cells. Thus, it is important to study DNA cleavage under irradiation without any additives such as metal and reducing agents for designing DNA binding drugs or as a site directed photonucleases for accessing structural and genetic information [16]. In addition to the biological significance, it is necessary to develop simple and effective synthetic routes for the organic compounds by using available reagents. Green approaches gaining great interest are grinding stone method [17-23] and microwave assisted synthesis [24-26] as these processes avoid toxic chemicals besides providing shorter reaction time. Today, there is great need to develop safe and environmentally friendly process without using volatile and toxic solvents. Perusal of literature revealed that 1-(subsituted)-4,4,6-trimethyl- 3,4-dihydropyrimidine-2(1H)-thione had already been synthesized by conventional method [27-29]. In continuation our ongoing interest towards the developments of greener protocols in organic synthesis and further to evaluate the potential of synthesized heterocycles, it was planned to explore the new and efficient methodology by non-conventional approaches for the synthesis of potent DNA cleaving and antibacterial agents. MATERIALS AND METHODS All the chemicals purchased from a common commercial supplier (Hi-media, Loba, S.D. Fine chemicals and Rankem) including solvents which were of LR grade and used as supplied. Double distilled water was used in the present investigation. Melting points were determined using Digital melting point apparatus (Paraffin bath) and are uncorrected. Thin layer chromatography was performed on silica gel G for TLC (Rankem) and the spots were visualized by iodine vapors or by irradiation with UV light (254nm). Microwave assisted synthesis were carried out in an open glass vessel on modified microwave oven model 2001 ETB with rotating tray and a power source 230V, at an output energy of 800W and 2450 MHz frequency. The microwave reactions were performed using on/off cycling to control the temperature. The 1 H NMR spectra of the compounds were recorded on Bruker spectrophotometer at 400 MHz instrument, using TMS as internal reference standard in DMSO d6. Infrared spectra were recorded using the KBr disc on Perkin Elmer RZX FTIR spectrophotometer. The mass spectra were recorded on Q-ToF Micro Waters LC-MS spectrometer. Chemical synthesis 1. Synthesis of 4-Isothiocynato-4-methylpentan-2-one (1) Sulphuric acid (1.1mol) was diluted with distilled ice cold water (100 ml) and was added over a period of 25 minutes to mesityl oxide (1 mol) at 15°C. Added ammonium thiocyanate (1.1mol) aqueous solution to the mixture at 21°C in one lot. Separated oily layer after 15 min stirring, washed with aqueous sodium carbonate solution and with distilled water. Finally, the oily layer dried using anhydrous sodium sulphate[27]. 2. General procedures for 1-(subsituted)-4,4,6-trimethyl-3,4- dihydropyrimidine-2(1H)-thione (3a-m) Method A The 4-Isothiocynato-4-methylpentan-2-one (0.01mol) and amine (0.01mol) were dissolved in 10 ml ethanol and added H2SO4 in catalytic amount. Then the reaction mixture subjected to refluxing on water bath and reaction progress was monitored by TLC. The content was cooled and solid was filtered, washed with alcohol and crystallized from glacial acetic acid. International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 6, Issue 3, 2014 Innovare Academic Sciences