Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Organic Chemistry

Bromination of N-substituted homophthalimides and tetrahydropyrido[4,3-d]- pyrimidine-5,7-diones produces 4,4-dibromohomophthalimide and 8,8-dibromo- tetrahydropyrido[4,3-d]pyrimidine-5,7-dione derivatives, respectively, that can be used as precursors for spiro derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiroisoquinoline and spirotetrahydropyrido [4,3-d]- pyrimidine-5,7-dione derivatives, respectively. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro derivatives. All new compounds are prepared by using the usual chemical conditions and microwave assisted conditions. The latter conditions improved the reaction yields, reduced reaction times and ameliorated the effects on the surrounding environment as the reactions are carried out in closed systems. In the second part of our research, mixing equimolecular amounts of ethyl acetoacetate was mixed with equimolecular amounts of thiourea and salicylaldehyde in ethanol in the presence of K₂CO₃ to produce compound 6-(2-Hydroxyphenyl)-2-mercapto-4-oxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile, similarly when salicylaldehyde was replaced with terephthaldehyde, two moles of both of ethyl acetoacetate and thiourea reacted with one mol of terephthaldehyde in ethanol in the presence of K₂CO₃ to produce compound 6,6'-(1,4-phenylene)bis(4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5- carbonitrile). While refluxed with iodomethane afforded 4-(2-hydroxyphenyl)-2-(methylthio)-6-oxo-1,6- dihydropyrimidine-5-carbonitrile and 6,6'-(1,4-phenylene)bis(2-(methylthio)-4-oxo-1,4- dihydropyrimidine-5-carbonitrile) afforded (1,4-phenylene)bis-S-methyl pyrimidine respectively

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