الفهرس 
General Introduction and Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
The original work of this thesis includes three parts beside the general introduction about synthesis, reactions and biological activities of 1,3,4-thiadiazoles, each part deals with synthesizing a set of new functionalized, condensed and non-condensed thiadiazole with other heterocycles aiming to enhance the biological activity of the thiadiazole nucleus, stearic acid was utilized as starting material for these syntheses. the biological activity of the new synthesized compounds was evaluated against some gram positive, gram negative bacteria and some fungi, also, the surface active properties after propoxylation of some synthesized compounds were determined as nonionic surfactants, Part 1 synthesis and reactions of 2-amino-5- heptadecyl-1,3,4-thiadiazole ; facile procedure for one pot synthesis of novel functionalized thiadiazoles, thiadiazolo[3,2-a]pyrimidines, imidazo[2,1-b]thiadiazole and triazole carrying a long chain moiety : in this part 2-amino - 5 - heptadecy l - 1, 3, 4 -thiadiazole (1) was prepared from the reaction of stearic acid and thiosemicarbazide in refluxing phosphorus oxychloride, in one-pot and convenient route, 1, 3 - dielectrophilic carbon compounds (ethyl cyanoacetate, ethyl acetoacetate, diethyl malonate, acetylacetone) and / or 1,2- dielectrophilic carbon compounds as oxalyl chloride were reacted in different solvents with 2-amino - 5 - heptadecy l - 1,3,4-thiadiazole and produced different products depending on the nature of 1,3- and 1,2- dielectrophilic carbon compounds employed and also on the reaction conditions, when the aminothiadiazole (1) was reacted with ethyl cyanoacetate in boiling ethanol, 2-cyano - N -(5-heptadecyl[1,3,4]thiadiazol-2-yl)acetamide (2) was obtained while When this reaction was carried out in boiling glacial acetic acid and in the presence of catalytic amount of sodium acetate, a bicyclic product of 5-amino - 2 - heptadecyl[1,3,4]thiadiazolo [3,2-a] pyrimidin-7-one (3) was btained when acetylacetone was refluxed in glacial acetic acid and sodium acetate as a catalyst, a sole product was obtained in a good yield, which assigned to be 4 - (5 - heptadecy l - [1,3,4]thiadiazo l - 2 - y limino)pentan-2-one (4), the same product was obtained when the reaction was carried out in ethanol, but when aminothiadiazole 1 was reacted with diethyl malonate, and / or ethy l acetoacetate in refluxing ethanol and / or glacial acetic acid in sodium acetate, the bicyclic products of thiadiazolo [3,2 - a] pyrimidine derivatives (5,6) were produced, the original work of this thesis includes three parts beside the general introduction about synthesis, reactions and biological activities of 1,3,4 -thiadiazoles, each part deals with synthesizing a set of new functionalized, condensed and non -condensed thiadiazole with other heterocycles aiming to enhance the biological activity of the thiadiazole nucleus, stearic acid was utilized as starting material for these syntheses, the biological activity of the new synthesized compounds was evaluated against some gram positive, gram negative bacteria and some fungi, also, the surface active properties after propoxylation of some synthesized compounds were determined as nonionic surfactants, Part 1 synthesis and reactions of 2 - amino - 5 - heptadecy l - 1,3,4 - thiadiazole ; facile procedure for one pot synthesis of novel functionalized thiadiazoles, thiadiazolo [3,2-a] pyrimidines, imidazo[2,1-b] thiadiazole and triazole carrying a long chain moiety : in this part 2 - amino - 5 - heptadecy l - 1,3,4-thiadiazole (1) was prepared from the reaction of stearic acid and thiosemicarbazide in refluxing phosphorus oxychloride. In one-pot and convenient route, 1,3- dielectrophilic carbon compounds (ethyl cyanoacetate, ethyl acetoacetate, diethyl malonate, acetylacetone) and / or 1,2 - dielectrophilic carbon compounds as oxaly l - chloride were reacted in different solvents with 2-amino - 5 -heptadecy l- 1,3,4 - thiadiazole and produced different products depending on the nature of 1,3 - and 1,2- dielectrophilic carbon compounds employed and also on the reaction conditions when the aminothiadiazole (1) was reacted with ethyl cyanoacetate in boiling ethano l,2 - cyano - N - (5 -heptadecyl [1,3,4] thiadiazo l - 2 - y l) acetamide (2) was obtained while When this reaction was carried out in boiling glacial acetic acid and in the presence of catalytic amount of sodium acetate, a bicyclic product of 5-amino- 2- heptadecyl [1,3,4] thiadiazolo[3,2-a]pyrimidin - 7 - one (3) was obtained when acetylacetone was refluxed in glacial acetic acid and sodium acetate as a catalyst, a sole product was obtained in a good yield, which assigned to be 4 - (5 - heptadecy l -[1,3,4]thiadiazol-2-ylimino)pentan-2-one (4), the same product was obtained when the reaction was carried out in ethanol, but when aminothiadiazole 1 was reacted with diethyl malonate, and / or ethy l acetoacetate in refluxing ethanol and/or glacial acetic acid in sodium acetate, the bicyclic products of thiadiazolo[3,2-a]pyrimidine derivatives (5,6) were produced, 1,2 - Dicarbony l compounds such as oxalylchloride was reacted with aminothiadiazole to yield imidazo[2,1-a]thiadiazole derivatives (7 the reaction of compound 1 with triethy l or thoformate, 2 - naphthaldehyde, succinic anhydride and hydroxylamine hydrochloride were achieved and produced compounds ; thiadiazolyl formamidate (8, schiff’s base (9), thiadiazolyl pyrrolidine (10) and triazole derivative 11) Part 2 behaviour of 5 - heptadecy l - 1,3,4 -hiadiazole formation of (azo hyrdrazono tautomer and cyclization of the product : diazotization of 2 - amino - 5 - heptadecy l - 1,3,4 -thiadiazole (1) with sodium nitrite in concentrated hydrochloric acid containing glacial acetic acid produce the non-isolated compound 5-heptadecyl- 1,3,4- thiadiazole - 2 - diazonium chloride (12) which was used in situ during the reaction with active methylene compounds (ethyl acetoacetate, ethyl cyanoacetate, diethyl malonate and acetylacetone). In all the synthesized compounds (13-16), azo hydrazono tautomerism was detected spectroscopically by IR and from fragmentation patterns of mass spectra. Also, it was detected chemically by reaction with nitrogen nucleophiles as hydrazine hydrate, hydroxylamine hydrochloride and thiourea which were reacted via azo tautomer and affording 5-heptadecy l - 2 - (5-hydroxy-3-methyl-1 H -pyrazo l -4 - ylazo)- 1,3,4 -thiadiazole (18), 5-heptadecy l - 2 - (5-hydroxy-3-methyl-isoxazol-4-ylazo)-1,3,4-thiadiazole (19), 5-(5-heptadecyl-[1,3,4] thiadiazo l- 2 - ylazo)- 2 -mercapto-6-methyl- pyrimidin-4-ol (20), While carbon electrophliles as phenylisocyanate was reacted via hydrazono tautomer to give 6-acetyl-2-(5-heptadecy l [1,3,4] thiadiazo l - 2 l)-4-phenyl- 2H -[1,2,4]triazine-3,5-dione (21), 5 - Heptadecyl-1,3,4-thiadiazole - 2 - diazonium chloride (12) was also reacted with β -naphthol through coupling reaction and gave the corresponding azo dye intermediate which converted to compound (17), UV-visible spectrum of the synthesized compounds was screened at concentration (1x10-5 M) and the maximum wave length (λ max) was determined (, λ, Part 3 : Synthesis of some condensed and non-condensed thiadiazoles based on 2-chloro - 5 - heptadecy l [1,3,4]thiadiazole : 2 - Chloro-5-heptadecy l[l,3,4]thiadiazole (22) was obtained by leaving the diazonium salt (12) for two hours at room temperature, Chlorothiadiazole was proved to be an easy access to synthesize some condensed and non-condensed thiadiazole systems.