The work in this thesis involves three parts. Part I: Synthesis: Acridone derivatives containing 1, 3, 4-oxadiazole and 1, 3, 4-thiadiazole rings are synthesized according to the following steps: Step one: Diphenylamine-2,4`-dicarboxylic acid [1] is obtained in a high yield by refluxing a mixture of 4-aminobenzoic acid and 2-chloro benzoic acid in the presence of catalytic amount of copper axide. [1]
Step two: 9(10H)-Acridone-2-carboxylic acid [2] is synthesized in ring closure reaction by heating compound [1] in sulfuric acid followed by basic hydrolysis.
[2]
Step three: Reaction of compound [2] with thiosemicarbazide in the presence of phosphorus oxychloride gave 2-[5-amino-1, 3, 4-thiadiazole-2-yl]-9(10H)-acridone.
[3]
Step four: Ethyl benzoate, ethyl-4-nitrobenzoate, ethyl-4-chlorobenzoate and ethyl-4-hydroxybenzoate were prepared by the usual esterification method through the reaction of the corresponding acid with absolute ethanol in the presence of catalytic amount of sulfuric acid.
[4] , [5] , [6 ] , [7]
Aryl hydrazines [8-11] were obtained by refluxing of the corresponding esters [4, 5, 6, and 7] and hydrazine hydrate in absolute ethanol.
[8] , [9] , [10] , [11]
Step five: Three of 2-[5-(4-substituted benzene)-1, 3, 4-oxadiazole-2-yl]-9(10H)-acridone were prepared through the cycloaddition reaction of compound [2] with the appropriate acid hydrazide [8, 9 and 10] in the presence of phosphorus oxychloride.
[12],[13],[14]
Step six: The condensation-cyclization reaction of 4-hydroxy benzoyl hydrazine with two equivalents of compound [2] in the presence of phosphorus oxychloride yielded the cyclized product .
[15]
Step seven The following acid chloride [16] was obtained by the reaction of compound [2] with thionyl chloride.
[16]
Esterification of compound [16] with absolute ethanol afforded the following ester [17] .
[17]
Thus on hydrazinolysis of this compound yielded the acid hydrazide derivative,[18].
[18]
Compound [18] was subjected to cyclodehydration by means of carbon disulfide in basic medium leading to the formation of 2-[5-thiol-1, 3, 4-oxadiazole-2-yl]-9(10H)-acridone.
[19]
Step eight: 2,4`-bis [5- (phenyl) -1,3,4-oxadiazole-2-yl] diphenylamine synthesized by reaction compound [1] with two equivalents of benzoyl hydrazine [8] in the presence of phosphorus oxychloride.
Step nine: Reaction of compound [1] with two equivalents of thiosemicarbazide in the presence of phosphorus oxychloride gives 2,4`-bis[5-(amino)-1,3,4-thiadiazole-2-yl]diphenylamine.
Step ten: Finally, two new Schiff bases [22,23] were synthesized by the reaction of compound [21] with two equivalents of benzaldehyde and 4-nitrobenzaldehyde , respectively .
Part II: Characterization:
Structures of all these synthesized compounds have been confirmed by spectral (FTIR, UV) data. The results were discussed and found in agreement with the suggested structures. Part III: Biological Activity: Antibacterial behavior of some of the synthesized compounds against two strains of bacteria has been investigated; the results obtained are listed in Table (3-2)