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词条 Reduction of nitro compounds
释义

  1. Aliphatic nitro compounds

     Reduction to hydrocarbons  Reduction to amines  Reduction to hydroxylamines  Reduction to oximes 

  2. Aromatic nitro compounds

     Reduction to anilines  Reduction to hydroxylamines  Reduction to hydrazino compounds  Reduction to azo compounds  Reduction to azoxy compounds 

  3. References

The chemical reactions described as reduction of nitro compounds can be affected by many reagents and reaction conditions. Historically, the nitro group was one of the first functional groups to be reduced.

Alkyl and aryl nitro compounds behave differently. Thus, reduction conditions can be broadly classified by starting materials: aliphatic nitro compounds or aromatic nitro compounds. Secondary classifications are based upon reaction products.

Aliphatic nitro compounds

Reduction to hydrocarbons

Hydrodenitration (replacement of a nitro group with hydrogen) is difficult to achieve but can be effected by catalytic hydrogenation over platinum on silica gel at high temperatures.[1]

The reaction can also be done through radical reaction with tributyltin hydride and a radical initiator, AIBN as an example.[2]

Reduction to amines

Aliphatic nitro compounds can be reduced to aliphatic amines by several reagents:

  • Catalytic hydrogenation using platinum(IV) oxide (PtO2)[3] or Raney nickel[4]
  • Iron metal in refluxing acetic acid[5]
  • Samarium diiodide[6]
  • Raney nickel, platinum on carbon, or zinc dust and formic acid or ammonium formate[7]

α,β-Unsaturated nitro compounds can be reduced to saturated amines by:

  • Catalytic hydrogenation over palladium-on-carbon
  • Iron metal
  • Lithium aluminium hydride[8] (Note: Hydroxylamines and oximes are typical impurities.)
  • Lithium borohydride or sodium borohydride and trimethylsilyl chloride[9]
  • Red-Al[10]

Reduction to hydroxylamines

Aliphatic nitro compounds can be reduced to aliphatic hydroxylamines using diborane.[11]

The reaction can also be carried out with zinc dust and ammonium chloride {{citation needed|date=April 2014}}:

R-NO2 + 4 NH4Cl + 2 Zn → R-NH-OH + 2 ZnCl2 + 4 NH3 + H2O

Reduction to oximes

Nitro compounds are typically reduced to oximes using metal salts, such as stannous chloride[12] or chromium(II) chloride.[13] Additionally, catalytic hydrogenation using a controlled amount of hydrogen can generate oximes.[14]

Aromatic nitro compounds

Reduction to anilines

The reduction of nitroaromatics is conducted on an industrial scale.[15] Many methods for the production of anilines from aryl nitro compounds exist, such as:

  • Catalytic hydrogenation using: Raney nickel[16] or nickel nanoparticles on zeolite,[17] palladium-on-carbon,[18] platinum(IV) oxide, or Urushibara nickel[7].
  • Iron in acidic media[19] (Note: Iron is particularly well suited for this reduction as the reaction conditions are typically gentle and also because iron has a high functional group tolerance.) (See Bechamp reduction)
  • Sodium hydrosulfite[20]
  • Sodium sulfide (or hydrogen sulfide and base). For example, reduction of a 1,3-dinitrobenzene derivative using sodium sulfide gives the 3-nitroaniline.[21]
  • Tin(II) chloride[22]
  • Titanium(III) chloride
  • Zinc
  • Samarium[23]
  • Raney nickel, platinum-on-carbon, or zinc dust and formic acid or ammonium formate[7]
  • Decaborane in presence of palladium-on-carbon and acetic acid[7]
  • Hydroiodic acid[24]

Metal hydrides are typically not used to reduce aryl nitro compounds to anilines because they tend to produce azo compounds. (See below)

Reduction to hydroxylamines

Several methods for the production of aryl hydroxylamines from aryl nitro compounds exist:

  • Raney nickel and hydrazine at 0-10 °C[25]
  • Electrolytic reduction[26]
  • Zinc metal in aqueous ammonium chloride[27]

Reduction to hydrazino compounds

{{see also|Hydrazine}}

Treatment of nitroarenes with excess zinc metal results in the formation of N,N-diarylhydrazine.[28]

Reduction to azo compounds

Treatment of aromatic nitro compounds with metal hydrides gives good yields of azo compounds. For example, one could use:

  • Lithium aluminium hydride[29]
  • Zinc metal with sodium hydroxide.[28] (Excess zinc will reduce the azo group to a hydrazino compound.)

Reduction to azoxy compounds

Aromatic compounds are reduced to azoxy compounds by using:

Na3AsO3 or glucose or NaOH[30]

C6H5NO2→ Azoxybenzene

References

1. ^{{cite journal |author1=M. J. Guttieri |author2=W. F. Maier |lastauthoramp=yes | title = Selective cleavage of carbon-nitrogen bonds with platinum | year = 1984 | journal = J. Org. Chem. | volume = 49 | issue = 16 | pages = 2875–2880 | doi = 10.1021/jo00190a006}}
2. ^T. V. (Babu) RajanBabu, Philip C. Bulman Page, Benjamin R. Buckley, "Tri-n-butylstannane" Encyclopedia of Reagents for Organic Synthesis 2004, John Wiley & Sons. doi:10.1002/047084289X.rt181.pub2
3. ^{{cite journal | author = A. T. Nielsen | title = The Isomeric Dinitrocyclohexanes. II. Stereochemistry | year = 1962 | journal = J. Org. Chem. | volume = 27 | issue = 6 | pages = 1998–2001 | doi = 10.1021/jo01053a019}}
4. ^{{OrgSynth | author = Dauben, Jr., H. J.; Ringold, H. J.; Wade, R. H.; Pearson, D. L.; Anderson, Jr., A. G. | title = Cycloheptanone | collvol = 4 | collvolpages = 221 | year = 1963 | prep = cv4p0221}}
5. ^{{cite journal | author = Senkus, M. | title = Ind. Eng. Chem. | year = 1948 | volume = 40 | pages = 506}}
6. ^{{cite journal |author1=A. S. Kende |author2=J. S. Mendoza |lastauthoramp=yes | title = Controlled reduction of nitroalkanes to alkyl hydroxylamines or amines by samarium diiodide | year = 1991 | journal = Tetrahedron Letters | volume = 32 | issue = 14 | pages = 1699–1702 | doi = 10.1016/S0040-4039(00)74307-3}}
7. ^1 2 3 {{Cite journal|last=Adams|first=J. P.|date=2002|title=Nitro and related groups|url=|journal=Journal of the Chemical Society, Perkin Transactions 1|language=en|volume=0|issue=23|pages=2586–2597|doi=10.1039/b009711j|issn=|via=}}
8. ^{{cite journal | author = A. Burger, M. L. Stein and J. B. Clements | title = Some Pyridylnitroalkenes, Nitroalkanols, and Alkylamines | year = 1957 | journal = J. Org. Chem. | volume = 22 | issue = 2 | pages = 143–144 | doi = 10.1021/jo01353a010}}
9. ^{{Cite journal|last=Giannis|first=A.|last2=Sandhoff|first2=K.|date=1989|title=LiBH4(NaBH4)/Me3SiCl, an Unusually Strong and Versatile Reducing Agent|journal=Angewandte Chemie International Edition in English|language=en|volume=28|issue=2|pages=218–220|doi=10.1002/anie.198902181}}
10. ^{{Cite journal|last=Butterick|first=John R.|last2=Unrau|first2=A. M.|date=1974|title=Reduction of β-nitrostyrene with sodium bis-(2-methoxyethoxy)-aluminium dihydride. A convenient route to substituted phenylisopropylamines|url=|journal=J. Chem. Soc., Chem. Commun.|language=en|volume=0|issue=8|pages=307–308|doi=10.1039/c39740000307|issn=|via=}}
11. ^{{cite journal | author = H. Feuer, R. S. Bartlett, B. F. Vincent and R. S. Anderson | title = Diborane Reduction of Nitro Salts. A New Synthesis of N-Monosubstituted Hydroxylamines | year = 1965 | journal = J. Org. Chem. | volume = 30 | issue = 9 | pages = 2880–2882 | doi = 10.1021/jo01020a002}}
12. ^{{cite journal |author1=Braun, V. J. |author2=Sobecki, W. | title = Über primäre Dinitro-, Nitronitrit- und Dialdoxim-Verbindungen der Fettreihe | journal = Ber. | year = 1911 | volume = 44 | issue = 3 | pages = 2526–2534 | doi = 10.1002/cber.19110440377}}
13. ^{{cite journal |author1=J. R. Hanson |author2=E. Premuzic |lastauthoramp=yes | title = Applications of chromous chloride--II : The reduction of some steroidal nitro-compounds | year = 1967 | journal = Tetrahedron | volume = 23 | issue = 10 | pages = 4105–4110 | doi = 10.1016/S0040-4020(01)97921-9}}
14. ^{{cite journal | author = C. Grundmann | title = Über die partielle Reduktion von Nitro-cyclohexan | year = 1950 | journal = Angewandte Chemie | volume = 62 | issue = 23–24 | pages = 558–560 | doi = 10.1002/ange.19500622304}}
15. ^{{cite journal|author=Gerald Booth|title=Nitro Compounds, Aromatic|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2007|publisher=Wiley-VCH|location=Weinheim|doi=10.1002/14356007.a17_411}}
16. ^{{OrgSynth | author = Allen, C. F. H.; VanAllan, J. | title = 2-Amino-p-cymene | collvol = 3 | collvolpages = 63 | year = 1955 | prep = cv3p0063}}
17. ^{{OrgSynth |author = Mazaheri O., Javad Kalbasi R. | title = Preparation and characterization of Ni/mZSM-5 zeolite with a hierarchical pore structure by using KIT-6 as silica template: an efficient bi-functional catalyst for the reduction of nitro aromatic compounds | DOI= 10.1039/C5RA02349A}}
18. ^{{OrgSynth | author = Bavin, P. M. G. | title = 2-Aminofluorene | collvol = 5 | collvolpages = 30 | year = 1973 | prep = cv5p0030}}
19. ^{{OrgSynth | author = Fox, B. A.; Threlfall, T. L. | title = 2,3-Diaminopyridine | collvol = 5 | collvolpages = 346 | year = 1973 | prep = cv5p0346}}
20. ^{{OrgSynth | author = Redemann, C. T.; Redemann, C. E. | title = 5-Amino-2,3-dihydro-1,4-phthalazinedione | collvol = 3 | collvolpages = 69 | year = 1955 | prep = cv3p0069}}
21. ^{{OrgSynth | author = Hartman, W. W.; Silloway, H. L. | title = 2-Amino-4-nitrophenol | collvol = 3 | collvolpages = 82 | year = 1955 | prep = cv3p0082}}
22. ^{{cite encyclopedia | last1 = Faul | first1 = Margaret M. | last2 = Thiel | first2 = Oliver R. | title = Encyclopedia of Reagents for Organic Synthesis | encyclopedia = Encyclopedia of Reagents for Organic Synthesis | year = 2005 | doi = 10.1002/047084289X.rt112.pub2 | chapter = Tin(II) Chloride | isbn = 9780470842898 }}
23. ^{{cite journal | doi = 10.1016/S0040-4039(00)00917-5 | journal = Tetrahedron Lett. | author = Basu, M. K. | title = Ultrasound-promoted highly efficient reduction of aromatic nitro compounds to the aromatic amines by samarium/ammonium chloride | year = 2000 | pages = 5603 | issue = 30 | volume = 41}}
24. ^{{Cite journal|last=Kumar|first=J. S. Dileep|last2=Ho|first2=ManKit M.|last3=Toyokuni|first3=Tatsushi|date=2001|title=Simple and chemoselective reduction of aromatic nitro compounds to aromatic amines: reduction with hydriodic acid revisited|url=|journal=Tetrahedron Letters|volume=42|issue=33|pages=5601–5603|doi=10.1016/s0040-4039(01)01083-8|issn=|via=}}
25. ^{{Cite journal |author1=Ayyangar, N. R. |author2=Brahme, K. C. |author3=Kalkote, U. R. |author4=Srinivasan, K. V. | title = Facile Transfer-Reduction of Nitroarenes to N Arylhydroxylamines with Hydrazine in the Presence of Raney Nickel | journal = Synthesis | year = 1984 | volume = 1984 | issue = 11 | pages = 938 | doi = 10.1055/s-1984-31027}}
26. ^{{OrgSynth | author = Harman, R. E. | title = Chloro-p-benzoquinone | collvol = 4 | collvolpages = 148 | year = 1963 | prep = cv4p0148}}
27. ^{{OrgSynth | author = Kamm, O. | collvol = 1 | collvolpages = 445 | year = 1941 | title = β-Phenylhydroxylamine | prep = cv1p0445}}
28. ^1 {{OrgSynth | author = Bigelow, H. E.; Robinson, D. B. | title = Azobenzene | collvol = 3 | collvolpages = 103 | year = 1955 | prep = cv3p0103}}
29. ^{{cite journal |author1=R. F. Nystrom |author2=W. G. Brown |lastauthoramp=yes | title = Reduction of Organic Compounds by Lithium Aluminum Hydride. III. Halides, Quinones, Miscellaneous Nitrogen Compounds | year = 1948 | journal = J. Am. Chem. Soc. | volume = 70 | issue = 11 | pages = 3738–3740 | doi = 10.1021/ja01191a057 | pmid=18102934}}
30. ^O.P.Tandon
{{DEFAULTSORT:Reduction Of Nitro Compounds}}

1 : Organic redox reactions
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