الفهرس | Only 14 pages are availabe for public view |
Abstract Utility of naturally occurring khellin in heterocyclic synthesis’’ Noura Ali Abd El-Fatah Department of Chemistry, Faculty of Education, Ain Shams University The chemical reactivity of 4,9-dimethoxy-5-oxo-5H-furo[3,2-g] chromene-6-carboxaldehyde (6-formylkhellin) (1) was studied towards a diversity of nitrogen nucleophilic reagents. Reaction of carboxaldehyde 1 with some primary amines and heterocyclic amines afforded the corresponding Schiff bases. Also, the reactivity of carboxaldehyde 1 was studied towards some hydrazine derivatives namely; 7-chloro-4-hydrazinoquinoline, 3-hydrazino-5,6-diphenyl-1,2,4-triazine, N4-phenylthiosemicarbazide and S-benzyl dithiocarbazate. 6-Formylkhellin (1) underwent ring transformation upon treatment with hydroxylamine hydrochloride producing 5-hydroxy-4,9-dimethoxy-7-oxo-7H-furo[3,2-g] chromene-6-carbonitrile (22). Some pyrimidine, [1,2,4]triazolo[4,3-a] pyrimidine, tetrazolo[1,5-a]pyrimidine and diazepine derivatives linked benzofuran were efficiently synthesized. Reaction of carboxaldehyde 1 with a variety of 1,4-binucleophiles produced furochromone fused benzodiazepine, pyridotriazepine, benzoxazepine and benzothiazepine derivatives. Some unsymmetrical thiocarbohydrazone were also synthesized. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data. The newly synthesized compounds were evaluated for their in vitro antibacterial activity Keywords: 6-Formylkhellin, furochromones, benzofurans, nucleophilic reagents, condensation, RORC, pyrazoles, pyrimidines, Schiff bases. Supervisors: Assist. prof. Magdy Ahmed Mohamed Ibrahim …………………………. Assist. Professor of Organic Chemistry, Faculty of Education, Ain Shams University. Dr. Nasser Mohamed Abdel-Fatah Ahmed …………………………. Lecturer of Organic Chemistry, Faculty of Education, Ain Shams University. |