2-Benzimidazyl And Hydrochloric Acid Synthesis Essay

2.3. Synthesis of 2-(2-(Morpholinomethyl)-1H-benzimidazol-1-yl)acetohydrazide (4)
To a solution of compound 3 (0.01 M, 2.89 g) in methanol (60 mL), 99% hydrazine hydrate (1 mL) was added and the mixture was refluxed for 6 h. The reaction mixture was cooled and the solid thus obtained was filtered, washed with cold water and recrystallized with ethanol to obtain the compound 4.
2.4. General procedure for synthesis of 1-{(5-substituted-1,3,4-oxadiazol-2-yl)methyl}-2-(morpholinomethyl)-1H-benzimidazoles (5a-r)
An equimolar mixture of compound 4 (0.001 M) and substituted carboxylic acid in phosphoryl chloride (POCl3) was refluxed for 8–12 h. Then reaction mixture was cooled, poured into ice-cold water and neutralized with 20% w/v NaHCO3 solution.

The animals were fasted for 24 h before the experiment with free access to water and were treated orally with two equal doses of either indomethacin (10 mg Kg-1 b.w.) or the test compounds (50 mg Kg-1 b.w.) at 0 and 12 h intervals, except the control group, which received 0.5% w/v CMC. After the drug treatment, the rats were fed a normal diet for 17 h and then sacrificed. The stomach was removed and opened along the greater curvature, washed with distilled water and cleaned gently by dipping in normal saline. The mucosal damage was examined by means of a microscope with a 4 × magnifying lens. The mucosal damage in each stomach was assessed according to the following scoring system: [{0.5 for redness; 1.0 for spot ulcers; 1.5 for hemorrhagic streaks; 2.0 for ulcers more than 3 but less than 5; 3.0 for more than five ulcers}. The mean score of each treated group minus the mean score of control group was regarded as severity index of gastric mucosal

After the evaluation of stomach for ulcers, the gastric mucosa of glandular portion was scrapped with the help of two glass slides, weighed (100 mg) and homogenized in 1 mL of a 0.15 M, ice cold potassium chloride (KCl) solution and centrifuged at 3,000 RPM for 10 minutes (REMI centrifuge). 1 mL of suspension was taken from the above tissue homogenate in test tube and 0.5 mL of 30% w/v TCA (trichloroacetic acid) was added to it, followed by 0.5 mL of 0.8% w/v TBA (thiobarbituric acid) reagent. The tubes were then covered with aluminium foil and kept in water bath for 30 minutes at 80 °C. After 30 minutes, tubes were taken out and kept in ice-cold water for 30 minutes and centrifuged at 3000 rpm for 15 minutes (R-BC DX REMI centrifuge). The absorbance of the supernatant was read in spectrophotometer (UV-1601, SHIMADZU) at 540 nm against blank. Blank consisted of 1 mL distilled water, 0.5 mL of 30% w/v TCA and 0.5 mL of 0.8% w/v TBA. The results were expressed as nM of MDA (malondialdehyde) formed /hr/ mg of