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Studies on density of substituted indole-3-carboxaldehyde in the mixture of benzene + methanol have been made. The cmc values in higher volume percent of methanol are higher than those in higher volume percent of benzene. Masson equation has been applied successfully to interpret apparent molar volume of compounds in benzene +methanol. The studies suggest that interactions between solute solvent molecule increases when non-polar hydrocarbon is predominant in solvent mixture whereas solute-solute interactions increases when methanol is predominant at below and above cmc.
In this study, various concentrations of ethanolic extracts of propolis (EEP) ranging from 0.03 to 1.0 mg/µL were tested against Staphylococcus aureus (ATCC25923) in vitro employing the disk diffusion technique. EEP showed significant antimicrobial activity against S. aureus with MIC of 0.06 mg/µL (p<0.005) and minimal bactericidal concentration (MBC) of 0.13 mg/µL (p<0.005). This finding suggests a potential use of propolis as an alternative treatment method in combating infections caused by S. aureus that have posed a problem in healthcare settings in Malaysia.
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A new high performance liquid chromatographic (HPLC) method was developed and validated for the determination of nateglinide in pharmaceutical formulations. Optimum separation was achieved in 12 minutes using C18 column (250 mm × 4.6 mm, i.d., particle size 5 mm), and elution was accomplished using a mobile phase (1mL/min). Detection was carried out using a UV detector set at 245 nm. A linear relationship between mean peak area and concentration of nateglinide was observed in the range 1-10 µg/mL, with a detection limit of 0.05 µg/mL and a quantification limit of 0.173 µg/mL. Intra-day and Inter-day precision, and accuracy of the methods have been established according to the current ICH guidelines. The developed method was successfully applied to the determination of nateglinide in pharmaceutical formulations. The results were statistically compared with those of the reference method (UV method) by applying Student's t-test and F-test. Accuracy, evaluated by means of the recovery method, was in the range 99.83 - 99.94%, with precision (RSD) 0.89%. No interference was observed from the coformulated substances. The proposed method was successfully employed for the determination of nateglinide in various pharmaceutical preparations.
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A simple, sensitive and specific spectrophotometric method has been developed for the determination of manganese (II) in benzene. The metal ion reacts with 2-hydroxy-4-n-butoxy-5-bromo propiophenone thiosemicarbazone (HBBrPT) forming a dark yellow coloured complex in the pH range 7.0-11.0. The complex shows maximum absorption at 440 nm. Beer's law is obeyed in the range 2.74-6.86 µg/ml. The molar absorptivity and Sandell's sensitivity are found to be 5229 l mol-1 cm-1 and 0.0105 µg cm-2, respectively. The solid complex have been isolated and characterized on the basis of elemental analysis, UV, IR, NMR and Mass spectra. HBBrPT is found to be a selective and strong chelating agent for manganese. The results deduced from Job's method of continuous variation, the mole ratio and the slope ratio method showed that metal: ligand ratio in the complex to be 1:2. The stability constant of the complex found to be 1.92 X 107. The free energy change for the complex formation reaction is found to be -10.158 K cal/mole at 32oC. The complex is fairly stable for about 24 h and up to 55oC.
In view of various biological activities of cinnoline derivatives like antibacterial, antioxidant, antineoplastic it was our interest to prepare fluoro-pyrimido-cinnolines and then substitute it with various anilines, morpholine, piperazine and to evaluate them for antimicrobial activity. Fluoro-pyrimido-cinnoline was synthesized by reaction between 4-fluoro-3-chloro-aniline with sodium nitrite in presence of conc. HCI to form diazonium salt solution. This on treatment with ethyl cyano-acetamide gives aryl-hydrazino(cyano)acetamide which reacts with chlorobenzene in the presence of AlCl3 to form 4-amino-3-cinnolino carboxamides which was further refluxed with formamide to give fluoro-pyrimido-cinnolines. Various fluoro-pyrimido-cinnoline derivatives were prepared by refluxing with morpholine, piperazine and substituted anilines in the presence of acetonitrile for 3-4 hours.
The condensation of 2,4-dihydro-2,5-disubstituted-3H-pyrazol- 3-ones (1) with substituted benzaldehyde (2) in presence of glacil acetic acid gives 4-arylmethylene-2,4-dihydro-2,5-disubstituted-3H- pyrazol-3-ones (3). Similarly, the 4-arylmethylene-2,4-dihydro-2,5- disubstituted-3H-pyrazol-3-ones (3) reacts with thioureal/ phenyl thiourea / urea/ phenyl urea in presence of alkaline solution of ethanol at reflux temperature to give l,3-disubstituted-4-substituted phenyl-6-imino / phenylimino-4,7 -dihydro-1,3-thiazino / oxazino [5,4-d] pyrazoles. The antibacterial activities of the compounds (4) were tested against S. aureus and B. cereus bacteria.
Complexes of 3-(4'-pyridyl)-4-Phenyltriazoline-5-thione have been prepared with Mg(II), Sn(II), Pb(II), Sb(II) and Bi(III) and characterized using various physico-chemical methods. The probable structures to these complexes have been assigned and mode of metal-ligand bonding has been investigated. The nature of shifting and change in intensity of all four thioamide bands of the ligand are used as diagnostic tool for metal-ligand bonding. The bonding through sulphur causes splitting of thio amide band IV. All the splitted bands are observed at lower frequencies.
Some novel Piperazine tetrazolium salts have been synthesised and their biological activity have been evaluated, these compounds exhibited moderate to good antibacterial activity.
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