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niketreaction-190310185849.pdf

27 Mar 2023
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niketreaction-190310185849.pdf

  1. ADVANCED ORGANIC CHEMISTRY Presented by : Niket D.Bajare [M.pharm First year] Guided by :Dr S. Pekamwar School of Pharmcy ,Nanded.
  2. Mechanism and Synthetic Application of Naming reaction • DIECKMANN REACTION • OZONOLYSIS REACTION
  3. DIECKMANN REACTION -It is named after the german chemist Walter Dieckmann (1869-1925) -certain diesters undergoes intramolecular condensation in the presence of strong base to produce B-keto esters this called as “Dieckmann condensation reaction”. -its ring forming reaction.
  4. General Reaction :-
  5. Mechanism....... -Deprotonation of an ester at the alpha-position generates an enolate ion which then undergoes a 5- exo-trig nucleophilic attack to give a cyclic enol. -protonation with a Bronsted-Lowry acid reforms the Beta-keto ester.
  6. Mechanism.........
  7. synthetic application.......... • It is used in the synthesis of various cyclopentane &cyclohexane derivative. • it is used in preparation of cyclic indole.(active against cancer)
  8. OZONOLYSIS
  9. what is ozonolysis ? • OZONOLYSIS is an organic reaction where the unsaturated bonds of alkenes,alkynes or azo compound are cleaved with ozone . • alkenes and alkynes form organic compound in which the multiple carbon-carbon bond has been replaced by a carbonyl group.while azo compound form nitrosamines. • the out come of reaction depends on the type of multiple bond being oxidised and work up condition.
  10. ozonolysis of alkenes............. • alkenes can oxidised with ozone to form alcohol,aldehyde,or ketone or carboxylic acid. • e.g- tetramethyl alkene which is undergoes ozonolysis in methanol at -78dc. to form the prop- 2-one and small amount of acids.
  11. reaction
  12. Mechanism .... • The alkene and ozone form an intermediate molozonide in a 1,3-dipolar cycloaddition. • the molozonide reverts to its corresponding carbonyl oxide and aldehyde or ketone in a retro-1,3-dipolar cycloaddition. • the oxide and aldehyde or ketone react again in a 1,3- dipolar cycloaddition or produce a relatively stable ozonide intermediate (a trioxolane )
  13. Synthetic application.... • It is used for structure elucidation of unknown organic compound containing carbon carbon double bond(c=c). C H3 (CH2)7 CH CH (CH2)7 COOH C H3 (CH2)7 COOH pelargonic acid O3 1) 2) H2O2 Oleic acid HOOC (CH2)7 COOH Azelaric acid +
  14. References :- • Organic chemistry Clayden, Greeves,Warren & Woihers ., Oxford University. • Wikipedia
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