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

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

1,2,* email and 1email
Received: 27 August 2012; in revised form: 23 September 2012 / Accepted: 26 September 2012 / Published: 18 October 2012
(This article belongs to the Section Theoretical Chemistry)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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.

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.

Chicago/Turabian Style

Khalil, Khaled D.; Al-Matar, Hamad 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, no. 10: 12225-12233.

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