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A novel synthesis of 1,3,5-trisubstituted pyrazoles through a spiro-pyrazoline intermediate via a tandem 1,3-dipolar cycloaddition/elimination
被引:49
作者:
Dadiboyena, Sureshbabu
[1
]
Valente, Edward J.
[2
]
Hamme, Ashton T., II
[1
]
机构:
[1] Jackson State Univ, Dept Chem, Coll Sci Engn & Technol, Jackson, MS 39217 USA
[2] Mississippi Coll, Dept Chem & Biochem, Clinton, MS 39058 USA
关键词:
Cycloaddition;
Ring fragmentation;
Heterocycles;
Spirocycles;
Tandem reactions;
Regioselectivity;
NITRILE IMINES;
NITROOLEFINS;
ISOXAZOLES;
HYDRAZONES;
CELECOXIB;
D O I:
10.1016/j.tetlet.2008.10.145
中图分类号:
O62 [有机化学];
学科分类号:
070303 ;
081704 ;
摘要:
The syntheses of an important class of hitherto unreported 1,3,5-pyrazoles, inspired by all unanticipated eliminatory ring opening are described, The reported pyrazole compounds were constructed through the Huisgen cyclization of 2-methylene-1,3,3-trimethylindoline and an in situ generated nitrile imine. The newly formed spiro-pyrazoline intermediate presumably then undergoes a ring opening/elimination process to afford a pyrazole, as evidenced by single X-ray crystal data. The Current report constitutes the first formal observation of this kind of ring opening involving a spiro-pyrazoline intermediate. Published by Elsevier Ltd.
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页码:291 / 294
页数:4
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