Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines

Khalil, Khaled D.; Al-Matar, Hamad M.

doi:10.3390/molecules171012225

Open AccessArticle

Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines

by

Khaled D. Khalil

^1,2,*

and

Hamad M. Al-Matar

¹

Chemistry Department, Faculty of Science, University of Kuwait, P.O. Box 5969, Safat 13060, Kuwait

²

Chemistry Department, Faculty of Science, Cairo University, Giza, 12613, Egypt

^*

Author to whom correspondence should be addressed.

Molecules 2012, 17(10), 12225-12233; https://doi.org/10.3390/molecules171012225

Submission received: 27 August 2012 / Revised: 23 September 2012 / Accepted: 26 September 2012 / Published: 18 October 2012

(This article belongs to the Section Organic Chemistry)

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Abstract

Coupling of 2-benzylmalononitrile with aromatic diazonium salts afforded 3-phenyl-2-arylhydrazonopropanenitriles 4a,b, which were rearranged into 2-cyanoindoles 5a,b upon heating with ZnCl₂ in the presence of glacial acetic acid. The produced indole derivatives 5a,b can be successfully used as valuable precursors to synthesize 1,2,4-oxadiazolylindoles 8a,b. The reaction of arylhydrazononitriles 4a,b with hydroxylamine afforded an amidoximes 9a,b that could be cyclized into 1,2,3-triazole-4-amines 10a,b. In addition, 4a,b could be converted into 4-aminopyrazoles 12a,b via condensation with chloroacetonitrile in the presence of triethylamine as a basic catalyst. Finally, compounds 12a,b were refluxed with dimethylformamide dimethylacetal (DMFDMA) to afford amidines 13a,b that were readily cyclized to the corresponding pyrazolo[4,3-d]pyrimidines 14a,b when refluxed with ammonium acetate.

Keywords: benzylidenemalononitrile; 2-arylhydrazononitrile; amidoxime; cyanoindole; dimethylformamide dimethylacetal; 1,2,3-triazole

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MDPI and ACS Style

Khalil, K.D.; Al-Matar, H.M. Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines. Molecules 2012, 17, 12225-12233. https://doi.org/10.3390/molecules171012225

AMA Style

Khalil KD, Al-Matar HM. Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines. Molecules. 2012; 17(10):12225-12233. https://doi.org/10.3390/molecules171012225

Chicago/Turabian Style

Khalil, Khaled D., and Hamad M. Al-Matar. 2012. "Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines" Molecules 17, no. 10: 12225-12233. https://doi.org/10.3390/molecules171012225

APA Style

Khalil, K. D., & Al-Matar, H. M. (2012). Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines. Molecules, 17(10), 12225-12233. https://doi.org/10.3390/molecules171012225

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Studies on 2-Arylhydrazononitriles: Synthesis of 3-Aryl-2-arylhydrazopropanenitriles and Their Utility as Precursors to 2-Substituted Indoles, 2-Substituted-1,2,3-Triazoles, and 1-Substituted Pyrazolo[4,3-d]pyrimidines

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