Hakki Erdogan

Second Derivative Spectrophotometric Determination of p-Aminophenol in the Presence of Paracetamol

Abstract A second derivative spectroscopic method for the determination of p-aminophenol in paracetamol powder is described. Second derivative absorbance (d2A/dλ2) values were measured at 223.8 nm (Δ = 4.2 nm) where p-aminophenol showed derivative responses obeying Beers Law but paracetamol had negligible derivative absorption. The concentrations of p-aminophenol solutions prepared in 0.1 N HCl (0.12–7.61 mcg/ml), containing constant amounts of paracetamol (20 mcg/ml) related linearly with the d2A/dλ2 values and gave a straight line (r = −0.9999). The method allowed determination of 0.5% to 38% of p-aminophenol in paracetamol without prior separation, it is rapid, precise and accurate.

Synthesis of 3-(4-substituted benzoylmethyl)-2-benzoxazolinones and screening antimicrobial activities.

A number of 3-(4-substituted benzoylmethyl)-2-benzoxazolinones have been synthesized by reacting with 2-benzoxazolinone and 4-substituted phenacyl bromide in ethanol. Their chemical structures were confirmed by IR, 1H NMR and elemental analysis. For screening antimicrobial activity, minimum inhibitory concentration (MIC) values were determined against two Gram positive, one Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) and three yeast-like the fungi (Candida albicans, Candida krusei, Candida parapsilosis).

Analgesic activity of acylated 2-benzoxazolinone derivatives

Ten new benzoxazolinone derivatives having a disubstituted benzoyl group at the six position of the ring were synthesized by reacting 2-benzoxazolinone with aromatic carboxylic acids in the presence of polyphosphoric acid. The structure of the compounds were elucidated by IR, 1H NMR, MS and elemental analysis. Analgesic activity was evaluated by a modified Koster test. Seven compounds showed analgesic activities higher than that of acetylsalicylic acid.

Synthesis of some novel 3-methyl-6-(2-substituted propanoyl/propyl)-2-benzoxazolinone derivatives and anti-nociceptive activity.

In this study, 12 new 3-methyl-6-(2-substituted aminopropanoyl)-2-benzoxazolinone and 3-methyl-6-(1-hydroxy-2-substituted aminopropyl)-2-benzoxazolinone derivatives have been prepared. Their structures have been elucidated by IR, 1H NMR spectra and by elementary analysis. The anti-nociceptive activity of these compounds has been investigated by using a modified Koster test. It was found that most compounds are capable of inducing anti-nociception in animals.

Novel Antiinflammatory Analgesics: 3-(2-/4-Pyridylethyl)-Benzoxazolinone and Oxazolo[4,5-β]pyridin-2-one Derivatives

Twenty‐two new 3‐[2‐(2‐and/or 4‐pyridyl)ethyl]benzoxazolinone and oxazolo[4,5‐b]pyridin‐2‐one derivatives have been synthesized by reacting 2‐and/or 4‐vinylpyridine and appropriate benzoxazolinones and oxazolo[4,5‐b]pyridine‐2‐one. Their chemical structures have been proven by IR, 1H‐NMR, 13C‐NMR, mass spectroscopy, and elemental analysis. The analgesic activities of these compounds were investigated by a modified Koster′s Test. Test results revealed that, at 100 mg/kg dose level, most of the compounds showed significant analgesic activities when compared to aspirin. Therefore the compounds were screened for their antiinflammatory activities using the carrageenan hind paw edema test. Compounds 1, 7, 10, 11, 12, 13, 15, 18, 20, 21 were found more active than indomethacine. In gastric ulceration studies gastrointestinal bleeding was not observed at 100 mg/kg dose level in compounds 1 and 2.

Synthesis and characterization of some new 2(3H)-benzoxazolones with analgesic and antiinflammatory activities

The synthesis, characterization and pharmacological activities of a new series of (6-difluorobenzoyl)-5-methyl-3-benzoylmethyl-2(3H)-benzoxazolone and 5-methyl-3-(2-hydroxyl-2-phenylethyl)-2(3H)-benzoxazolone are described. Antiinflammatory activity was investigated by the carrageenin-induced paw oedema test and analgesic activity by acetic acid writhing and hot plate tests in mice. Among the synthesized compounds, compound 3e 6-(2,5-difluorobenzoyl)-3-(4-bromobenzoylmethyl-2(3H)-benzoxazolone was found to be the most promising compound for analgesic activity. Reduced compounds (4a–4d) displayed considerable anti-inflammatory activity compared to the other derivatives.

Differential Pulse Polarographic Determination of Some (5-Nitro-2-Furl)Alkylidene-2-Hydrazinothiazole Derivatives

Abstract The differential pulse polarographic analysis of four (5-nitro-2-furyl)alkylidene-2-hydrazinothiazole derivatives are presented, 0.1 M tetramethylammonium tetrafluoroborate solution was found to be the best supporting electrolyte. At static mercury drop electrode the nitro group of the compounds studied was reduced to the amine in a six-electron process. Linear response was observed over 0.2 to 140 mg.L−1 with a relative standard deviation of 3.3%.

Synthesis and Evaluation of Analgesic, Anti-Inflammatory and Antioxidant Activities of New 6-Acyl-3-alkyl-5-methyl-2 (3H) -benzoxazolones

A new series of 6-acyl-3-alkyl-5-methyl-2(3H)-benzoxazolones have been obtained starting from 5-methyl-2(3H)-benzoxazolone. All the compounds have been characterized by IR, 1H-NMR and mass spectroscopy. The new compounds were screened for analgesic and anti-inflammatory activities and ulcerogenic effect. The in vitro antioxidant capacity of the synthesized compounds were tested by the nitric oxide radical scavenging assay. Most of the compounds showed antiinflammatory activity. Among them, 3-[4-(4-fluorophenyl)piperazinomethyl] -6-(3-chlorobenzoyl)-5-methyl-2(3H)-benzoxazolone (3j) was found more potent than the reference drug indometacin (CAS 53-86-1) with 41.66% decrease in edema. Compared with the control, some of the compounds exhibited analgesic effects. Similar to the anti-inflammatory activity results, compound 3j showed the highest analgesic profile with 48.56% inhibition. No active hemorragic focus was observed in the microscopic evaluation in the ulcerogenic effect studies of the tested compounds. 6-(3-Chlorobenzoyl)-5-methyl-2(3H)-benzoxazolone (2b) and 3-[4-(4-fluorophenyl-piperazino)methyl]-6-(3-chlorobenzoyl)-5-methyl-2(3H)-benzoxazolone (3j) showed nearly maximum antioxidant activity compared to ascorbic acid (CAS 50-81-7) with IC50 values of 27.6 and 30.1 microg/mL, respectively.