A. Z. Nasr | Researchain

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Advances in Heterocyclic Chemistry | 1990

Synthesis of condensed 1,2,4-triazolo [3,4-z] heterocycles

M. A. E. Shaban; A. Z. Nasr

Publisher Summary This chapter discusses the synthesis of condensed 1,2,4-triazolo[3,4-z]- heterocycles. The synthesis of condensed 1,2,4-triazolo[3,4-z]- heterocycles is arranged according to the complexity of the ring directly fused to the 1,2,4-triazole nucleus (irrespective of other rings that might be fused to it) beginning with those rings having one nitrogen atom in a five-membered ring and proceeding with those that are more complex. The heterocycles are arranged in the following order according to their types of heteroatoms: nitrogen, oxygen, sulfur, and other elements. Consideration is given to the possible alternative nomenclature of some 1,2,4- triazoles[3,4-z]heterocycles such as heterocyclo[n,m-c] 1,2,4-triazoles (n,m are numbers indicating linkage positions of the heterocycle to the traizole ring) in order to comply with the nomenclature rules of the IUPAC.

Journal of Carbohydrate Chemistry | 1995

Synthesis of 1,3,4-Thiadiazole and 1,2,4-Triazole acyclo C-Nucleosides

M. A. E. Shaban; A. Z. Nasr; Mamdouh A.M. Taha

Abstract Reaction of 4-arylthiosemicarbazides (1) with 2,3,4,5-tetra-O-acetylgalactaroyl dichloride (2) gave the corresponding 2,3,4,5-tetra-O-acetylgalactaroyl-bis(4-aryl-thiosemicarbazides (3). The latter compounds underwent dehydrative cyclization by heating with phosphoryl chloride to give 1,2,3,4-tetra-O-acetyl-1,4-bis(5-arylamino-1,3,4-thiadiazol-2-yl)galacto-tetritols (4) which afforded, upon de-O-acetylation with methanolic ammonia, the corresponding 1,4-bis(5-arylamino-1,3,4-thiadiazol-2-yl)-galacto-tetritols (5). Compounds 3 were also cyclodehydrated, in a different way, with concomitant de-O-acetylation upon treatment with ethanolic sodium ethoxide to give 1,4-bis(4-aryl-5-thioxo-1,2,4-triazol-3-yl)galacto-tetritols (6). Acetylation of 6 with acetic anhydride in the presence of pyridine afforded 1,2,3,4-tetra-O-acetyl-1,4-bis(1-acetyl-4-aryl-5-thioxo-1,2,4-triazol-3yl)galacto-tetritols (7). Compounds 3a, 3b and 6a-c showed no antibacterial activity against Bacillus subtilis, Escherichia coli, P...

Advances in Heterocyclic Chemistry | 1997

THE CHEMISTRY OF C-NUCLEOSIDES AND THEIR ANALOGS I : C-NUCLEOSIDES OF HETERO MONOCYCLIC BASES

M. A. E. Shaban; A. Z. Nasr

Pharmazie | 1995

Synthesis of acyclo C-nucleosides : 3-(alditol-1-yl)-5-methyl-7-oxo-1,2,4-triazolo[4,3-a]pyrimidines

M. A. E. Shaban; Mamdouh A.M. Taha; A. Z. Nasr; A. E. A. Morgaan

Pharmazie | 1999

Synthesis of acyclo C-nucleosides : Sterically controlled regiospecific heterocyclization of aldehydo-sugar {5-methyl-1,2,4-triazino[5,6-b]indol-3-yl}-hydrazones to 3-(alditol-1-yl)-10-methyl-1,2,4-triazolo[4'3': 2,3]1,2,4-triazino[5,6-b]-indoles

M. A. E. Shaban; A. Z. Nasr; A. E. A. Morgaan

Pharmazie | 1995

Synthesis of acyclo C-nucleoside analogs : 6-(D-gluco-pentitol-1-yl)-1,2,4-triazolo[3,4-b]1,3,4-thiadiazoles and 1,4-bis(1,2,4-triazolo[3,4-b]1,3,4-thiadiazol-6-yl) galacto-tetritols

M. A. E. Shaban; A. Z. Nasr; Mamdouh A.M. Taha

Pharmazie | 1996

Synthesis of acyclo C-nucleosides : 3-(alditol-1-yl)-6,7-diphenyl-1,2,4-triazolo[4,3-b][1,2,4]triazines

M. A. E. Shaban; Mamdouh A.M. Taha; A. Z. Nasr

Pharmazie | 1991

Reactions of 4-aryl-1-hydrazinophthalazines with carbonyl compounds.

M. A. E. Shaban; Mamdouh A.M. Taha; A. Z. Nasr

Die Pharmazie | 2003

Oxidative cyclization of D-fructose thiosemicarbazones to 2-amino-5-(D-arabino-1,2,3,4-tetrahydroxybut-1-yl)-1,3,4-thiadiazoles through carbon-carbon bond cleavage of the sugar chain.

M. A. E. Shaban; M. A. Mostafa; A. Z. Nasr

Archive | 1991

SYNTHESIS AND BIOLOGICAL ACTIVITIES OF SOME 1,3,4-OXADIAZOLES AND BIS (1,3,4-OXADIAZOLES)

M. A. E. Shaban; A. Z. Nasr; Susan M. El-Badry

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