Synthesis of 2,3-Difunctionalized 4-Nitropyrroles

Nishiwaki, Nagatoshi; Nakanishi, Masataka; Hida, Takahiko; Miwa, Yuko; Tamura, Mina; Hori, Koichi; Tohda, Yasuo; Ariga, Masahiro

doi:10.1021/jo010566l

Cited by 25 publications

(6 citation statements)

References 36 publications

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“…Nitroisoxazolone 5a readily reacted with amines to afford aamino-b-nitroenamines (nitroketene aminals) and amidoximes 21 and underwent ring transformation to afford polyfunctionalized pyrroles upon treatment with sodium enolates of 1,3-dicarbonyl compounds (Scheme 3). 22 Upon heating in DMF at 100 • C in the absence of a nucleophile, isoxazolone 5a was found to remain intact, but bubbles were formed in the reaction mixture after activated carbon was added. From this mixture, bis(Nmethylcarbamoyl)-1,2,5-oxadiazole-2-oxide (furoxan) (6) could be isolated in 40% yield (based on 5a), indicating the in situ generation of carbamoylnitrile oxide (2d, R 1 = Me, R 2 = H) from nitroisoxazolone 5a and the concurrent elimination of carbon dioxide.…”

Section: Resultsmentioning

confidence: 99%

“…22 Upon heating in DMF at 100 °C in the absence of nucleophile, isoxazolone 5a was found to remain intact, but bubbles were formed in the reaction mixture after activated carbon was 25 added. From this mixture, bis(N-methylcarbamoyl)-1,2,5-oxadiazole-2-oxide (furoxan) (6) could be isolated in 40% yield (based on 5a), indicating the in situ generation of carbamoylnitrile oxide (2d, R 1 = Me, R 2 = H) from nitroisoxazolone 5a and the concurrent elimination of carbon 30 dioxide.…”

Section: Resultsmentioning

confidence: 99%

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An anomalous hydration/dehydration sequence for the mild generation of a nitrile oxide

et al. 2011

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A nitrile oxide having a carbamoyl group is readily generated upon the treatment of 2-methyl-4-nitro-3-isoxazolin-5(2H)-one with water under mild reaction conditions, even in the absence of special reagents. The obtained nitrile oxide undergoes cycloaddition with dipolarophiles, alkynes 10 and alkenes, to afford the corresponding isoxazol(in)es, which are useful intermediates in the synthesis of polyfunctionalized compounds. A plausible mechanism underlying the formation of the nitrile oxide is proposed, which involves an anomalous hydration/dehydration sequence. DFT calculations were also performed to support this mechanism.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

An anomalous hydration/dehydration sequence for the mild generation of a nitrile oxide

et al. 2011

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“…The nitroisoxazolone 177 was considered by the authors as the hidden form of the substituted nitroenamine (Scheme 59). 115 Finally, Moradi and co-workers reported a one-pot threecomponent synthesis of pyrrolo [1,2-a]pyrazines 181 from ethylenediamine 91, acetylenic esters 180 and nitrostyrene derivatives 40 (Scheme 60). 116 The reaction was performed via initial stirring of the ethylenediamine 91 (1.2 equiv.)…”

Section: And Benzene Ring In 127bmentioning

confidence: 99%

Part I: Nitroalkenes in the synthesis of heterocyclic compounds

2014

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The applications of nitroalkenes in the synthesis of three-to five-membered O, N and S-heterocycles, including natural products are investigated in this review. These heterocyclic compounds were synthesized from nitroalkenes with a variety of substituents at the a and b-positions and those that were part of common and medium rings via a wide variety of reactions such as Michael addition reactions, epoxidation, [3 + 2] cycloaddition and many cascade/domino/tandem reactions. In addition, the potential of nitroalkenes to take part in multi-component and cascade reactions, particularly, in diastereo-and enantioselective versions is reviewed. The high reactivity of nitroalkenes and their potential to coordinate with the metal catalysts as well as organocatalysts signify them as efficient precursors in synthetic organic chemistry. Also, the flexibility of the nitro group in functional group manipulations has expanded the scope of the nitro group, in general, and nitroalkenes, in particular, in organic synthesis.

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“…We previously demonstrated nitrile oxide having a carbamoyl group is generated by only stirring nitroisoxazolone 17) in water at room temperature without any base or special reagent 18) . The cycloaddition of nitrile oxide with versatile alkenic or alkynic dipolarophiles effectively proceeds to afford corresponding 3-carbamoyl-2-isoxazolines and isoxazoles in moderate to high yields ( ).…”

Section: Introductionmentioning

confidence: 99%