Synthesis and Antibacterial Activity of Chalcones and Pyrimidine-2-ones

Some new chalcones have been prepared by Claisen-schmidt condensation of ketone and different aromatic aldehydes. These chalcones on condensation with urea in presence of acid gave Pyrimidine-2-ones. The synthesized compounds have been characterized by elemental analysis, IR and 1 H NMR spectral data. They have been screened for their antibacterial activity against Gram positive bacteria B. subtillis & S. aureus and Gram negative bacteria E. coli & S. typhi.


Introduction
The chemistry of chalcones have been recognized as a significant field of study.2][3] Besides this they show antifungal 4 , insecticidal 5 , anaesthetic 6 , anti-inflammatory, analgesic and ulcerogenics 7 properties.Pyrimidines and their derivatives are considered to be important as drugs and agricultural chemicals.Some substituted pyrimidines and their derivatives have been reported to possess interesting biological activities such as hypnotic properties 8 , antifungal 9 , antitumour 10 , activities.Many pyrimidines are used as thyroid drugs. 11

Experimental
Melting points of synthesized compounds have been taken in open capillaries and are uncorrected.Purity of compounds were checked by TLC on silica gel coated glass plates.IR spectra were recorded by preparing pallets in KBr on Shimatzu FT-IR 8300 spectrophotometer. 1 H NMR spectra recorded on "Perkin Elmer Model -32 NMR spectrometer" of 300 MHz using TMS as an internal standard.All the synthesized compounds have been screened for their antibacterial activity.

A. K. PAREKH et al.,
4a-4h Preparation of chalcones 2-Hydroxy-4-isopropoxy-5-nitro-acetophenone (0.01mole) dissolved in ethanol and various substituted aromatic aldehydes (0.01mole) dissolved in ethanol were mixed and potassium hydroxide solution (40%, 25ml) was added to it drop wise with stirring and kept overnight at room temperature.The content was then poured over crushed ice and acidified with cold dilute HCl (10%).The solid thus separated was filtered, washed with water, dried and crystallised from acetic acid.

Results and Discussion
Structures of the compounds synthesized have been confirmed by elemental analysis, IR spectra and 1 H NMR spectra.

Table - 3
The synthesized compounds were tested for their antibacterial activity by measuring the inhibition area on agar plates (diffusimetric method)12with Gram positive bacteria B. subtillis & S. aureus and Gram negative bacteria E. coli & S typhi as test germs.The results of antibacterial screening indicated that very good activity was shown by compound 3d against all four organisms while compound 3g was found to possess moderate activity against Gram negative bacteria but poor activity against Gram positive bacteria.Compounds 4d, 4f and 4h exhibited very good activity.Other compounds showed moderate activity against both Gram positive and Gram negative bacteria.112 A. K. PAREKH et al., Antibacterial Activity of Newly Synthesized Compounds, Zone of Inhibition (mm).