Reaction of N-Monosubstituted Hydrazones with Nitroolefins: A Novel Regioselective Pyrazole Synthesis

Xiaohu Deng* and Neelakandha S. Mani

*Department of Drug Discovery, Johnson & Johnson Pharmaceutical R&D LLC, 3210 Merryfield Row, San Diego, California 92121, Email: xdengprdus.jnj.com

X. Deng, N. S. Mani, Org. Lett., 2006, 8, 3505-3508.

DOI: 10.1021/ol061226v

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Abstract

A regioselective one-pot synthesis of substituted pyrazoles from N-monosubstituted hydrazones and nitroolefins gives products in good yields. A key nitropyrazolidine intermediate is characterized and a plausible mechanism is proposed.

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proposed mechanism

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Regioselective Synthesis of 1,3,5-Tri- and 1,3,4,5-Tetrasubstituted Pyrazoles from N-Arylhydrazones and Nitroolefins

X. Deng, N. S. Mani, J. Org. Chem., 2008, 73, 2412-2415.

Base-Mediated Reaction of Hydrazones and Nitroolefins with a Reversed Regioselectivity: A Novel Synthesis of 1,3,4-Trisubstituted Pyrazoles

X. Deng, N. S. Mani, Org. Lett., 2008, 10, 1307-1310.

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Key Words

pyrazoles, 1,3-dipolar cycloaddition, oxygen

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ID: J54-Y2006-2320