New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems
Experimental evidence on the powerful biological activity of pirazolo[1,5-a]pyrimidines] has been supported by several reports in the last years, which has made possible their wide utilization in the pharmaceutical industry. For this reason, the synthesis of these condensed heterocycles has been car...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Centro Nacional de Investigaciones Científicas
2004-05-01
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| Series: | Revista CENIC Ciencias Químicas |
| Online Access: | https://revista.cnic.cu/index.php/RevQuim/article/view/1465 |
| _version_ | 1797399342813806592 |
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| author | Maribel Nápoles Klaus Peseke José Quincoces Arístides Rosado Arturo Macías Hermán Vélez |
| author_facet | Maribel Nápoles Klaus Peseke José Quincoces Arístides Rosado Arturo Macías Hermán Vélez |
| author_sort | Maribel Nápoles |
| collection | DOAJ |
| description | Experimental evidence on the powerful biological activity of
pirazolo[1,5-a]pyrimidines] has been supported by several reports in the last
years, which has made possible their wide utilization in the pharmaceutical
industry. For this reason, the synthesis of these condensed heterocycles has
been carried out with increasing interest. The purpose of the work was to develop
a new simpler synthesis method with good yields and purity than those reported
for obtaining similar structures. Therefore the presence of reactive centres in
alquene and dithiethane push pull systems was taken into account making
possible the intramolecular cyclization subsequently to the initial nucleophilic
attack of the cyanoacetahydrazide. The reaction behavior was studied in aloholic
medium as dimethylformamide. In all cases, best results were achieved by using
the aprotic dipolar solvent since it allows the stabilization of the polar transition
states formed through the reaction course. It was demonstrated that the
dithiethanes are less reactive than the keten-S,S-acetals. A reaction scheme is
showed which is agreement with the general reaction mechanism proposed by
Rappaport for the interaction between nucleophiles and push pull ethylenes.
The structures of the most stable intermediate was established on the basis of
the calculations performed by means of the MOPAC 6.0 program. The compounds
synthesized were characterized adequately by means of their elemental
quantitative analysis and several spectroscopic techniques IR, NMR, including
the COLOC method, and the Mass Spectrometry. |
| first_indexed | 2024-03-09T01:38:54Z |
| format | Article |
| id | doaj.art-32a49a3c528644e9a6f40cde1f719a37 |
| institution | Directory Open Access Journal |
| issn | 2221-2442 |
| language | English |
| last_indexed | 2024-03-09T01:38:54Z |
| publishDate | 2004-05-01 |
| publisher | Centro Nacional de Investigaciones Científicas |
| record_format | Article |
| series | Revista CENIC Ciencias Químicas |
| spelling | doaj.art-32a49a3c528644e9a6f40cde1f719a372023-12-08T20:44:34ZengCentro Nacional de Investigaciones CientíficasRevista CENIC Ciencias Químicas2221-24422004-05-013510170211627New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systemsMaribel NápolesKlaus PesekeJosé QuincocesArístides RosadoArturo MacíasHermán VélezExperimental evidence on the powerful biological activity of pirazolo[1,5-a]pyrimidines] has been supported by several reports in the last years, which has made possible their wide utilization in the pharmaceutical industry. For this reason, the synthesis of these condensed heterocycles has been carried out with increasing interest. The purpose of the work was to develop a new simpler synthesis method with good yields and purity than those reported for obtaining similar structures. Therefore the presence of reactive centres in alquene and dithiethane push pull systems was taken into account making possible the intramolecular cyclization subsequently to the initial nucleophilic attack of the cyanoacetahydrazide. The reaction behavior was studied in aloholic medium as dimethylformamide. In all cases, best results were achieved by using the aprotic dipolar solvent since it allows the stabilization of the polar transition states formed through the reaction course. It was demonstrated that the dithiethanes are less reactive than the keten-S,S-acetals. A reaction scheme is showed which is agreement with the general reaction mechanism proposed by Rappaport for the interaction between nucleophiles and push pull ethylenes. The structures of the most stable intermediate was established on the basis of the calculations performed by means of the MOPAC 6.0 program. The compounds synthesized were characterized adequately by means of their elemental quantitative analysis and several spectroscopic techniques IR, NMR, including the COLOC method, and the Mass Spectrometry.https://revista.cnic.cu/index.php/RevQuim/article/view/1465 |
| spellingShingle | Maribel Nápoles Klaus Peseke José Quincoces Arístides Rosado Arturo Macías Hermán Vélez New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems Revista CENIC Ciencias Químicas |
| title | New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems |
| title_full | New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems |
| title_fullStr | New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems |
| title_full_unstemmed | New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems |
| title_short | New method for synthesis of pyrazolo[1,5-a]pyrimidines from cyanoacetohydrazide and push pull systems |
| title_sort | new method for synthesis of pyrazolo 1 5 a pyrimidines from cyanoacetohydrazide and push pull systems |
| url | https://revista.cnic.cu/index.php/RevQuim/article/view/1465 |
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