Molecules | |
Green One Pot Solvent-Free Synthesis of Pyrano[2,3-c]-Pyrazoles and Pyrazolo[1,5-a]Pyrimidines | |
Hamad M. Al-Matar1  Khaled D. Khalil1  Aisha Y. Adam1  | |
[1] 1Chemistry Department, Faculty of Science, University of Kuwait, P.O. Box 5969, Safat, 13060 Kuwait 2Chemistry Department, Faculty of Science, Cairo University, Giza, 12613, Egypt | |
关键词: pyranopyrazole; multi-component synthesis; aminopyrazolinone; pyrazolo[1; 5-a]pyrimidine; cyanoacetic acetic anhydride; NOE difference experiments; | |
DOI : 10.3390/molecules15096619 | |
来源: mdpi | |
【 摘 要 】
Pyrano[2,3-c]pyrazoles are obtained via mixing ethyl acetoacetate, hydrazine hydrate, aldehydes or ketones and malononitrile in the absence of solvent. These same products were also obtained by reacting arylidenemalononitriles 3 with 3-methyl-2-pyrazolin-5-ones. NOE difference experiments confirmed that these products exist solely in the 2H form. Similar treatments of 3-amino-2-pyrazolin-5-one with arylidene-malononitrile afforded adduct 6. Similarly mixing ethyl cyanoacetate, hydrazine hydrate, aldehydes, with malononitrile gave the same product 6. A novel synthesis of 4-oxo-4H-pyrano[2,3-c]pyrazole (8) could be achieved via reacting 3-methyl-2-pyrazolin-5-one with a mixture of cyanoacetic acid and acetic anhydride. Similar treatment of 3-aminopyrazole 11 with the benzylidene-malononitrile produced the pyrazolo[2,3-a]pyrimidines 12a,b.
【 授权许可】
CC BY
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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