nucleophilic substitution in acyl chlorides

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Nucleophilic Substitution in Acyl Chlorides. ••. OH. ••. O. O. • •. • •. R. C. C. C. Y. R. X. R. Y. X. General Mechanism for Nucleophilic Acyl Substitution. involves formation and dissociation of a tetrahedral intermediate. H Y. -H X. O. O. (CH 3 ) 2 CHC OH. - PowerPoint PPT Presentation

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  • Nucleophilic Substitutionin Acyl Chlorides

  • General Mechanism for Nucleophilic Acyl Substitutioninvolves formation and dissociation of a tetrahedral intermediateHY-HX

  • Preparation of Acyl Chloridesfrom carboxylic acids and thionyl chloride SOCl2heat+SO2+HCl(90%)

  • Reactions of Acyl Chlorides

  • Reactions of Acyl Chlorides++HClAcyl chlorides react with carboxylic acids to give acid anhydrides:

  • Reactions of Acyl Chlorides++HClAcyl chlorides react with carboxylic acids to give acid anhydrides:via:

  • Example+pyridine(78-83%)

  • Reactions of Acyl Chlorides++HClAcyl chlorides react with alcohols to give esters:R'OH

  • Reactions of Acyl Chlorides++HClAcyl chlorides react with alcohols to give esters:R'OHvia:

  • Example+(CH3)3COHpyridine(80%)

  • Reactions of Acyl Chlorides++H2OAcyl chlorides react with ammonia and amines to give amides:R'2NH+ HO+Cl

  • Reactions of Acyl Chlorides++H2OAcyl chlorides react with ammonia and amines to give amides:R'2NH+ HO+Clvia:

  • Example+NaOH(87-91%)H2O

  • Reactions of Acyl Chlorides++HClAcyl chlorides react with water to give carboxylic acids (carboxylate ion in base):H2O++Cl2HO+H2O

  • Reactions of Acyl Chlorides++HClAcyl chlorides react with water to give carboxylic acids (carboxylate ion in base):H2Ovia:

  • Example+H2O+HCl

  • ReactivityAcyl chlorides undergo nucleophilic substitution much faster than alkyl chlorides.C6H5CH2ClRelative rates of hydrolysis (25C)1,0001

  • Preparation ofCarboxylic Acid AnhydridesAnhydrides can be prepared from acyl chlorides

  • Some anhydrides are industrial chemicalsAcetic anhydridePhthalic anhydrideMaleic anhydride

  • From dicarboxylic acidsCyclic anhydrides with 5- and 6-membered rings can be prepared by dehydration of dicarboxylic acids(89%)+ H2O

  • Reactions ofCarboxylic Acid Anhydrides

  • Reactions of Anhydrides

  • Reactions of Acid Anhydridesnormally, symmetrical anhydrides are used (both R groups the same)reaction can be carried out in presence of pyridine (a base) or it can be catalyzed by acids++Carboxylic acid anhydrides react with alcohols to give esters:R'OH

  • Reactions of Acid Anhydrides++Carboxylic acid anhydrides react with alcohols to give esters:R'OHvia:

  • Example(60%)H2SO4

  • Reactions of Acid Anhydrides++Acid anhydrides react with ammonia and amines to give amides:2R'2NH

  • Reactions of Acid Anhydrides++Acid anhydrides react with ammonia and amines to give amides:2R'2NHvia:

  • Example(98%)+

  • Reactions of Acid Anhydrides+2RCOHAcid anhydrides react with water to give carboxylic acids (carboxylate ion in base):H2O+2RCO+2HOH2O

  • Reactions of Acid Anhydrides+2RCOHAcid anhydrides react with water to give carboxylic acids (carboxylate ion in base):H2O

  • Example+H2O

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