Journal article
A new method for functionalizing alpha,gamma-dinitro compounds at the beta-position: application to the cyclization of beta-alkoxy-alpha,gamma-dinitro compounds
Journal of physical organic chemistry, v 27(1)
01 Jan 2014
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Abstract
Treatment of 2,4-dinitropentane with bromine and sodium methoxide in methanol, affords formation of an ether product, 2,4-dibromo-3-methoxy-2,4-dinitropentane, in 59% yield as a mixture of three diastereomers. This observation has led to a general synthesis of 3-alkoxy-2,4-dibromo-2,4-dinitropentanes, obtained in 75-86% yield from 2,4-dibromo-2,4-dinitropentane as the preferred reactant. 4-Bromo-2,4-dinitro-2-pentene has been identified as an intermediate in these reactions. The nitroalkene has been isolated and undergoes conjugate addition with alkoxides to afford the same ether products after brominative work-up. The nitroalkene undergoes conjugate addition with sodium azide to give 3-azido-2,4-dibromo-2,4-dinitropentane in 38% yield as a mixture of two isomers in which the (R*,R*) isomer predominates. Sequential treatment of 2,4-dibromo-2,4-dinitropentane with sodium methoxide followed by sodium iodide and acetic acid gives 3-methoxy-2,4-dinitropentane in 63% yield, the overall product of simple methoxylation of 2,4-dinitropentane. However, attempted complete debromination of 2,4-dibromo-3-methoxy-2,4-dinitropentane with excess sodium iodide and acetic acid results only in monodebromination to give 2-bromo-3-methoxy-2,4-dinitropentane in 86% yield. Likewise, 2-bromo-3-ethoxy-2,4-dinitropentane is formed in 93% yield from the ethoxy analog. A mechanistic rationale is offered for condition-specific removal of the second Br atom in these reactions. Treatment of 3-methoxy-2,4-dinitropentane with potassium acetate/iodine in dimethyl sulfoxide affords formation of 4,5-dihydro-3,4-dimethyl-3-methoxy-4-nitroisoxazole 2-oxide in 30% yield as a single diastereomer. Conversion of 2-bromo-3-methoxy-2,4-dinitropentane in 15% yield to 4,5-dihydro-3,4-dimethyl-3-methoxy-4-nitroisoxazole 2-oxide is also possible by using potassium acetate in dimethyl sulfoxide. The mechanistic pathways for formation of 4,5-dihydro-3,4-dimethyl-3-methoxy-4-nitroisoxazole 2-oxide apparently involve unstable 3-methoxy-1,2-dimethyl-1,2-dinitrocyclopropane as the common intermediate. Similarly, 2-bromo-3-ethoxy-2,4-dinitropentane affords 4,5-dihydro-3-ethoxy-3,4-dimethyl-4-nitroisoxazole 2-oxide in 13% yield. Copyright (c) 2013 John Wiley & Sons, Ltd.
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Details
- Title
- A new method for functionalizing alpha,gamma-dinitro compounds at the beta-position: application to the cyclization of beta-alkoxy-alpha,gamma-dinitro compounds
- Creators
- Peter A. Wade - Drexel UniversityChristopher E. Castillo - Drexel UniversityNicholas Paparoidamis - Drexel University
- Publication Details
- Journal of physical organic chemistry, v 27(1)
- Publisher
- Wiley
- Number of pages
- 9
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]; Chemistry
- Web of Science ID
- WOS:000328554300005
- Scopus ID
- 2-s2.0-84890572049
- Other Identifier
- 991019167983704721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Chemistry, Organic
- Chemistry, Physical