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Nitrite Ion, Nitrous Acid, and Nitrosyl Cation Nitrite Ion, Nitrous Acid, and Nitrosyl Cation H H + + O O •• •• •• •• N N O O •• •• •• •• O O •• •• •• •• N N O O •• •• •• •• H H H H + + O O •• •• N N O O •• •• H H H H + + + + •• •• N N O O •• •• + + O O H H H H
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Nitrite Ion, Nitrous Acid, and Nitrosyl Cation H+ –O NO O NO H H+ O NO HH + + NO + O HH.

Jan 16, 2016

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  • Nitrite Ion, Nitrous Acid, and Nitrosyl Cation+

  • Nitrosyl Cation and Nitrosation

  • Nitrosyl Cation and Nitrosation+

  • Nitrosation of Primary Alkylaminesanalogous to nitrosation of secondary amines to this point+H+H+HRRH

  • Nitrosation of Primary Alkylaminesthis species reacts furtherRH

  • Nitrosation of Primary AlkylaminesRH

  • Nitrosation of Primary Alkylamines

  • Nitrosation of Primary Alkylamines+ NNO RH

  • Nitrosation of Primary Alkylamines

  • Nitrosation of Primary Alkylaminesnitrosation of a primary alkylamine gives an alkyl diazonium ionprocess is called diazotization+

  • Alkyl Diazonium Ions alkyl diazonium ions readily lose N2 to give carbocations+

  • Nitrosation of Primary Arylaminesgives aryl diazonium ionsaryl diazonium ions are much more stable than alkyl diazonium ionsmost aryl diazonium ions are stable under the conditions of their formation (0-10C)

  • Nitrosation of Primary Arylaminesgives aryl diazonium ionsaryl diazonium ions are much more stable than alkyl diazonium ionsmost aryl diazonium ions are stable under the conditions of their formation (0-10C) fastslowAr++N2

  • Example:HSO4

  • Synthetic Origin of Aryl Diazonium Salts

  • 22.18Synthetic Transformations of Aryl Diazonium Salts

  • Transformations of Aryl Diazonium Salts

  • Preparation of Phenolshydrolysis of a diazonium saltH2O, heat

  • Example2. H2O, heat1. NaNO2, H2SO4 H2O, 0-5C(73%)

  • Transformations of Aryl Diazonium Salts

  • Preparation of Aryl Iodidesreaction of an aryl diazonium salt with potassium iodideKI

  • Example2. KI, room temp.1. NaNO2, HCl H2O, 0-5C(72-83%)IBr

  • Transformations of Aryl Diazonium Salts

  • Preparation of Aryl Fluoridesheat the tetrafluoroborate salt of a diazonium ion;process is called the Schiemann reaction

  • Example(68%)2. HBF41. NaNO2, HCl, H2O, 0-5C3. heat

  • Transformations of Aryl Diazonium Salts

  • Preparation of Aryl Chlorides and Bromidesaryl chlorides and aryl bromides are prepared by heating a diazonium salt with copper(I) chloride or bromidesubstitutions of diazonium salts that use copper(I) halides are called Sandmeyer reactions

  • Example(68-71%)NH2NO22. CuCl, heat1. NaNO2, HCl, H2O, 0-5CClNO2

  • Example(89-95%)2. CuBr, heat1. NaNO2, HBr, H2O, 0-10CBrCl

  • Transformations of Aryl Diazonium Salts

  • Preparation of Aryl Nitrilesaryl nitriles are prepared by heating a diazonium salt with copper(I) cyanidethis is another type of Sandmeyer reaction

  • Example(64-70%)2. CuCN, heat1. NaNO2, HCl, H2O, 0CCNCH3

  • Transformations of Aryl Diazonium Salts

  • Transformations of Aryl Diazonium Saltshypophosphorous acid (H3PO2) reduces diazonium salts; ethanol does the same thingthis is called reductive deamination

  • Example(70-75%)NaNO2, H2SO4, H3PO2

  • Value of Diazonium Salts1) allows introduction of substituents such as OH, F, I, and CN on the ring2) allows preparation of otherwise difficultly accessible substitution patterns

  • Example(74-77%)NaNO2, H2SO4, H2O, CH3CH2OH(100%)

  • 22.19Azo Coupling

  • Azo CouplingDiazonium salts are weak electrophiles.React with strongly activated aromatic compounds by electrophilic aromatic substitution.

  • Azo CouplingDiazonium salts are weak electrophiles.React with strongly activated aromatic compounds by electrophilic aromatic substitution.+an azo compoundAr' must bear a strongly electron-releasing group such as OH, OR, or NR2.

  • Example+Cl

    10101010101010101010101818202132222222222222222222222222222222222222222223222222

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