Aromatic Compounds

4,153 views

Published on

Published in: Technology

Aromatic Compounds

  1. 1. RETROSYNTHETIC APPROCH TO ORGANIC SYNTHESIS Dr. Shaikh S. Nizami Department of Chemistry University of Karachi
  2. 2. <ul><li>RETROSYNTHESIS </li></ul><ul><li>OF </li></ul><ul><li>AROMATIC </li></ul><ul><li>COMPOUNDS </li></ul>
  3. 3. CONTENTS 1.Aromatic Eletrophilic Substitution Reactions 2.Aromatic Nucleophilic Substitution Reactions
  4. 4. Retrosynthesis of Aromatic Electrophilic Substitution Reactions Addition of cationic synthons to the aromatic ring
  5. 5. Reagents for Aromatic Electrophilic Substitution
  6. 6. Reagents for Aromatic Electrophilic Substitution
  7. 7. Friedel-Crafts Alkylation
  8. 8. Retrosynthesis of BHT & Synthesis
  9. 9. Friedel-Crafts Acylation
  10. 10. Friedel-Crafts Acylation
  11. 11. One-carbon electrophile for aromatic synthesis
  12. 12. Retrosynthesis of Piperonol (perfumery compound) & Synthesis
  13. 13. AROMATIC SIDE CHAINS BY Function Group Interconversion Y X Reagent Reduction -NO 2 -NH 2 H 2 , Pd, C Sn, conc.HCl -COR -CH(OH)R NaBH 4 -COR -CH 2 R Zn/Hg/conc.HCl
  14. 14. AROMATIC SIDE CHAINS BY Functional Group Interconversion Oxidation Y X Reagent - CH 2 Cl -CHO hexamine - CH 2 R -CO 2 H KMnO 4 -CH 3 - COR -OCOR R’CO 3 H
  15. 15. Aromatic Side Chains by Functional Group Interconversion Substitution Y X Reagent -CH 3 -CCl3 Cl 2 ,PCl 5 - CCl 3 -CF3 SbF 5 -CN -COOH HO-, H 2 O
  16. 16. Nucleophilic Aromatic Substitution Reactions Addition of an oxygen atom to an aromatic ring Add anionic reagents RO - to an Aromatic compound with a leaving Group .
  17. 17. Nucleophilic Aromatic Substitution <ul><li>Nucleophilic aromatic substitution works best when the leaving groups is N 2 (diazonium salts) </li></ul><ul><li>The synthetic sequence is </li></ul><ul><li>nitration, reduction,diazotisation </li></ul><ul><li>and substitution </li></ul>
  18. 18. Nucleophilic Aromatic Substitution
  19. 19. Retrosynthesis of Phenol
  20. 20. Synthesis HNO 3 H 2 SO 4 Sn/H + HOAc Br 2 NaOH NaNO 2 /HCl H 2 O
  21. 21. Aromatic compounds made by nucleophilic displacement of daizonium salts Reagent_____ HO H 2 O RO ROH CN Cu(I)CN Br/Cl Cu(I)Br/Cu(I)Cl I KI H H 3 PO 2 or EtOH/H + ____Z_____
  22. 22. Retrosynthetic analysis & synthesis Subst. FGI
  23. 23. SYNTHESIS HNO 3 H 2 SO 4 H 2 Pd,c NaNO 2 ,HCl Cu(I)CN
  24. 24. NUCLEOPHILIC SUBSTITUTION OF HALIDES Direct displacement of halide from an aromatic ring is possible only if : There are ortho and para nitro groups OR Similar electron-withdrawing groups
  25. 25. NUCLEOPHILIC SUBSTITUTION OF HALIDES HNO 3 H 2 SO 4 Nu -
  26. 26. Retrosynthetic analysis Trifluralin B- a herbicide
  27. 27. SYNTHESIS HNO 3 H 2 SO 4 base N-Pr 2 NH

×