الفهرس 
Study of the reactions of 2- aminobenzimidazole with aldehydes and diketone derivativesOnly 14 pages are availabe for public view
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Abstract
Thesis Titles: Utilization of eco-friendly chemical catalysts in one-pot multicomponent synthesis of diverse heterocyclic scaffolds of expected biological properties
Name: Nagwa Mourad Abd El Azeem Helal
National Research Centre
Abstract: In the present thesis, a novel catalyst (silica sulfuric acid / ethylene glycol) for the synthesis of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives have been demonstrated. Silica sulfuric acid / ethylene glycol was able to modify the reaction protocol and successfully benzo[4,5]imidazo[1,2-a]pyrimidine derivatives were obtained in high yield and high purity with short reaction times via the multi-component condensation reactions of 2-aminobenzimidazole, aldehydes and dicarbonyl compounds (or cyanomethyl derivatives). Silica sulfuric acid / ethylene glycol offer several advantages such as simplicity, mild reaction conditions, high yields, and little environmental impact.
The three-component reaction of 2-aminobenzimidazole and acetyl acetone with aldehyde in afforded the corresponding benzo[4,5]imidazo[1,2-a]pyrimidine derivatives 1a-g in good yields (60-93%). When benzoylacetone was left to react with different aldehydes and 2-amino- benzimidazole afforded the corresponding benzo[4,5]imidazo[1,2-a]pyrimidine derivatives 2a-g in yields from 58% to 97%. Thus, 2-aminobenzimidazole and 1,3-diphenylpropane-1,3-dione were reacted with aldehyde afforded the corresponding benzo[4,5]imidazo[1,2-a]pyrimidine derivatives 3a-g in good yields (76-97%). The 2-aminobenzimidazole and malononitrile were reacted with different aldehydes in glycol catalyst to afford the corresponding 2-amino-4-aryl-1,4-dihydro benzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitrile derivatives 4a-f in good yields (83-97%). the three-component condensation of ethyl cyanoacetate with 2-aminobenzimidazole and different aldehydes, leading to two products 5a-g and their oxizied 6a-g. The 2-amino- benzimidazole and cyanoacetamide were reacted with aldehyde to form the corresponding benzo[4,5]imidazo[1,2-a]pyrimido[4,5-d]pyrimidin-4(1H)-one derivatives 10a-e. The 2-amino- benzimidazole and acetyl acetone were reacted with aldehyde and afforded the corresponding benzo[4,5]imidazo[1,2-a]pyrimidine derivatives 11a-g in good yields (70-94%). Finally, the reaction of 2-aminobenzimidazole, aldehydes and diethyl malonate afforded two types of products 2-hydroxyethyl 3-hydroxy-4-aryl-2-oxo-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]- pyrimidine-3-carboxylate derivatives 15 and 4-aryl-3,4-dihydrobenzo[4,5]imidazo[1,2-a]- pyrimidin-2(1H)-one derivatives 16.
Evaluation of antitumor activity for the synthesized compounds was carried out to probe their activity. The compounds were found to have moderate to weak antitumor activity.
Keywords: silica sulfuric acid / ethylene glycol, 2-aminobenzimidazole, aldehydes, diketones, active methylenes, ketoesters, diesters, benzo[4,5]imidazo[1,2-a]pyrimidines, benzo[4,5]- imidazo[1,2-a]pyrimidine-3-carbonitriles, benzo[4,5]imidazo[1,2-a]pyrimido[4,5-d]pyrimidin-4(1H)-ones, 2-hydroxyethyl 3-hydroxy-4-aryl-2-oxo-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxylate derivatives and 4-aryl-3,4-dihydrobenzo[4,5]imidazo[1,2-a]- pyrimidin-2(1H)-one derivatives.