SYNTHESIS AND TAUTOMERISM OF NEW 1-n-ALKYL-5-PYRAZOLONE DERIVATIVES
3-Phenyl-5-pyrazolone (1) is selectively alkylated at position 1 in 40% yield. The alkylated compound (2) is acylated (3) in 60% yield and nitrosated (4) in 80% yield. According to the spectroscopic data a N-H or O-H structure can be proposed for 1 in DMSO. The proton may be at N-2 or on the oxygen...
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| Autores principales: | , , , |
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| Lenguaje: | English |
| Publicado: |
Sociedad Chilena de Química
1999
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| Materias: | |
| Acceso en línea: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0366-16441999000300014 |
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| Sumario: | 3-Phenyl-5-pyrazolone (1) is selectively alkylated at position 1 in 40% yield. The alkylated compound (2) is acylated (3) in 60% yield and nitrosated (4) in 80% yield. According to the spectroscopic data a N-H or O-H structure can be proposed for 1 in DMSO. The proton may be at N-2 or on the oxygen at C-5, respectively. The alkylated compound 2 exists as 5-pyrazolone in chloroform with a CH2 at C-4. In DMSO, 2 is a 5-hydroxypyrazole. For compound 3 in chloroform the structure corresponds to 4-acyl-5-hydroxypyrazole. For compound 4 in chloroform there is one tautomer with a 4-nitroso-5-hydroxypyrazole structure while in DMSO the same 4-nitroso-5-hydroxypyrazole (92%) and a 4-nitroso-5-pyrazolone (8%) tautomer can be found |
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