ISSN 2415-1297 (Online)   ISSN 2415-1300 (Print)
Volume : 27 Issue : 3 Year : 2019
Synthesis of Condensed 1,2,4-Triazolo-Heterocycles [Med J Islamic World Acad Sci]
Med J Islamic World Acad Sci. 1990; 3(4): 255-261

Synthesis of Condensed 1,2,4-Triazolo-Heterocycles

Mohammed A. E. Shaban1, Adel Z. Nasr1, Mamdouh A. M. Taha2
1From Department of Chemistry, Faculty of Science, Alexandria University, Alexandria, Egypt.
2From Department of Chemistry, Faculty of Education, Cairo University (Faroum Branch), Egypt.

Dehydrogenative cyclization of hydrazones derived from aromatic aldehydes and 2-hydrazino-1,3-benzothiazole, 2-hydrazinoquinoline, 2-hydrazinolepidine and 2-hydrazinopyridine using different dehydrogenating or oxidizing agents gave the corresponding 3-aryl-1,2,4-triazolo [3,4-b] 1,3-benzothiazoles, 3-aryl-1,2,4-triazolo [4,3-a] quinolines, 3-aryl-1,2,4-triazolo [4,3-a] lepidines and 3-aryl-1,2,4-triazolo [4,3-a] pyridines respectively. 1-Aroyl-2-(1,3-benzothiazol-2-yl)-, 1- aroyl-2-(quinol-2-yl)- and 1-aroyl-2-(lepid-2-yl) hydrazines were also prepared and their dehydrative cyclization using acetyl chloride was attempted. Under the used conditions 1-aroyl-2-(quinol-2-yl) hydrazines directly cyclized to 1,2,4-triazolo [4,3-a] quinolines while 1-aroyl-2-(1,3-benzothiazol-2-yl) hydrazines and 1-aroyl-2- (lepid-2-yl) hydrazines gave 1-acety-2-aroyl-1-1-(1,3-benzothiazol-2-yl) hydrazines and 1-acetyl-2-aroyl-1-(lepid-2-yl) hydrazines respectively. The latter were successfully cyclized through the elimination of an acetic acid molecule to the corresponding 3-aryl-1,2,4-triazolo-heterocycle by heating in boiling phenol.

Keywords: Hydrazines, hydrazones, cyclization.

Mohammed A. E. Shaban, Adel Z. Nasr, Mamdouh A. M. Taha. Synthesis of Condensed 1,2,4-Triazolo-Heterocycles. Med J Islamic World Acad Sci. 1990; 3(4): 255-261

Corresponding Author: Mohammed A. E. Shaban, Egypt

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