1 / 31

Nucleophilic Substitution in Acyl Chlorides

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.

joella
Download Presentation

Nucleophilic Substitution in Acyl Chlorides

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nucleophilic Substitutionin Acyl Chlorides

  2. •• OH •• O O •• •• R C C C Y R X R Y X General Mechanism for Nucleophilic Acyl Substitution involves formation and dissociationof a tetrahedral intermediate HY -HX

  3. O O (CH3)2CHCOH (CH3)2CHCCl Preparation of Acyl Chlorides from carboxylic acids and thionyl chloride SOCl2 + + SO2 HCl heat (90%)

  4. O RCCl O O RCOCR' O RCOR' O RCNR'2 O RCO– Reactions of Acyl Chlorides

  5. O O O O RCOCR' RCCl R'COH Reactions of Acyl Chlorides Acyl chlorides react with carboxylic acids to giveacid anhydrides: + + HCl

  6. O O O O RCOCR' RCCl R'COH H O O R OCR' C Cl Reactions of Acyl Chlorides Acyl chlorides react with carboxylic acids to giveacid anhydrides: + + HCl via:

  7. O O CH3(CH2)5CCl CH3(CH2)5COH O O CH3(CH2)5COC(CH2)5CH3 Example + pyridine (78-83%)

  8. O O RCOR' RCCl Reactions of Acyl Chlorides Acyl chlorides react with alcohols to give esters: + + R'OH HCl

  9. O O RCOR' RCCl H O R OR' C Cl Reactions of Acyl Chlorides Acyl chlorides react with alcohols to give esters: + + R'OH HCl via:

  10. O O C6H5COC(CH3)3 C6H5CCl Example pyridine + (CH3)3COH (80%)

  11. O O RCNR'2 RCCl Reactions of Acyl Chlorides Acyl chlorides react with ammonia and aminesto give amides: + + R'2NH + HO– H2O + Cl–

  12. O O RCNR'2 RCCl H O R NR'2 C Cl Reactions of Acyl Chlorides Acyl chlorides react with ammonia and aminesto give amides: + + R'2NH + HO– H2O + Cl– via:

  13. O O C6H5CN C6H5CCl HN Example NaOH + H2O (87-91%)

  14. O O RCOH RCCl O O RCO– RCCl Reactions of Acyl Chlorides Acyl chlorides react with water to givecarboxylic acids (carboxylate ion in base): + + H2O HCl + + 2HO– Cl– + H2O

  15. O O RCOH RCCl H O R OH C Cl Reactions of Acyl Chlorides Acyl chlorides react with water to givecarboxylic acids (carboxylate ion in base): + + H2O HCl via:

  16. O O C6H5CH2COH C6H5CH2CCl Example + + H2O HCl

  17. O C6H5CCl Reactivity • Acyl chlorides undergo nucleophilic substitution much faster than alkyl chlorides. C6H5CH2Cl Relative rates ofhydrolysis (25°C) 1,000 1

  18. Preparation ofCarboxylic Acid Anhydrides • Anhydrides can be prepared from acyl chlorides

  19. O O O O CH3COCCH3 O O O O Some anhydrides are industrial chemicals Aceticanhydride Phthalicanhydride Maleicanhydride

  20. O O H COH H C tetrachloroethane O 130°C C H H COH O O From dicarboxylic acids • Cyclic anhydrides with 5- and 6-membered rings can be prepared by dehydration of dicarboxylic acids + H2O (89%)

  21. Reactions ofCarboxylic Acid Anhydrides

  22. O O RCOCR' O RCOR' O RCNR'2 O RCO– Reactions of Anhydrides

  23. O O O O RCOR' RCOCR RCOH Reactions of Acid Anhydrides Carboxylic acid anhydrides react with alcoholsto give esters: • normally, 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 + + R'OH

  24. O O O O RCOR' RCOCR RCOH H O R OR' C OCR O Reactions of Acid Anhydrides Carboxylic acid anhydrides react with alcoholsto give esters: + + R'OH via:

  25. O O + CH3CHCH2CH3 CH3COCCH3 OH O CH3COCHCH2CH3 CH3 Example H2SO4 (60%)

  26. O O O O RCNR'2 RCO– RCOCR + R'2NH2 Reactions of Acid Anhydrides Acid anhydrides react with ammonia and aminesto give amides: + + 2R'2NH

  27. O O O O RCNR'2 RCO– RCOCR H + O R'2NH2 R NR'2 C OCR O Reactions of Acid Anhydrides Acid anhydrides react with ammonia and aminesto give amides: + + 2R'2NH via:

  28. O O H2N CH(CH3)2 CH3COCCH3 O CH3CNH CH(CH3)2 Example + (98%)

  29. O O O RCOCR O O O RCOCR Reactions of Acid Anhydrides Acid anhydrides react with water to givecarboxylic acids (carboxylate ion in base): + H2O 2RCOH + + 2HO– 2RCO– H2O

  30. O O O RCOCR H O R OH C OCR O Reactions of Acid Anhydrides Acid anhydrides react with water to givecarboxylic acids (carboxylate ion in base): + H2O 2RCOH

  31. O O COH O COH O O Example + H2O

More Related