Reaction of carbonyl compounds

THIS POWERPOINT CONTAIN REACTION OF CARBONYL COMPOUNDS WITH MACHANISM OF THE FOLLOWING
1. CONDENSATION
2. ALDOL CONDENSATION
3. CROSSED ALDOL CONDENSATION
4. CANNIZZARO REACTION
5. CROSSED CANNIZZARO REACTION
6. BENZOIN CONDENSATION
7. PERKIN CONDENSATION

1. BY – VISHAL SINGH SOLANKI CORPORATE INSTITUTE OF PHARMACY, BHOPAL VISIT MY YOUTUBE CHANNEL – PHARMARISING OR VISHAL SINGH SOLANKI REACTION OF CARBONYL COMPOUNDS 1. CONDENSATION 2. ALDOL CONDENSATION 3. CROSSED ALDOL CONDENSATION 4. CANNIZZARO REACTION 5. CROSSED CANNIZZARO REACTION 6. BENZOIN CONDENSATION 7. PERKIN CONDENSATION

2. 1. CONDENSATION 2. ALDOL CONDENSATION 3. CROSSED ALDOL CONDENSATION 4. CANNIZZARO REACTION 5. CROSSED CANNIZZARO REACTION 6. BENZOIN CONDENSATION 7. PERKIN CONDENSATION CONTENT BY – VISHAL SINGH SOLANKI

3. condensation reaction  is the combination of two molecules to form a single molecule, usually with the loss of a small molecule such as water. CONDENSATION condensation of two amino acids to give a  peptide bond . BY – VISHAL SINGH SOLANKI

4. Aldol condensation occurs in aldehydes having  α-hydrogen  with a dilute base to give  β-hydroxy aldehydes   called aldols. This reaction is most commonly known as aldol condensation. If the condensation reaction occurs between two different carbonyl compounds it is called  crossed aldol condensation . An  aldol condensation   is a condensation reaction in organic chemistry in which an enol or an enolate ion reacts with a carbonyl compound to form a β- hydroxyaldehyde or β-hydroxyketone, followed by dehydration to give a conjugated enone . ALDOL CONDENSATION BY – VISHAL SINGH SOLANKI

5. EXAMPLE - CONTI… BY – VISHAL SINGH SOLANKI

6. Step-1: In reverse order, The hydroxide ion deprotonates the aldehyde. MECHANISM OF ALDOL CONDENSATION BY – VISHAL SINGH SOLANKI

7. Step-2: Here Enolate ion 1 adds to the unreacted aldehyde. CONTI… BY – VISHAL SINGH SOLANKI

8. Step-3: Alkoxide ion 2 is protonated by water. CONTI… BY – VISHAL SINGH SOLANKI

9. Step-4: A small amount of aldol is converted into enolate ion (4) by hydroxide ion CONTI… BY – VISHAL SINGH SOLANKI

10. Step-5: Here Enolate Ion(4) loses a hydroxide ion CONTI… BY – VISHAL SINGH SOLANKI

11. The condensation reaction between two different molecules of an  aldehyde or ketone   in a protic solvent such as water or alcohol constitutes the crossed aldol reaction. When condensation is between two different carbonyl compounds, it is called crossed aldol condensation. CROSSED ALDOL CONDENSATION + BY – VISHAL SINGH SOLANKI

12. The  Cannizzaro reaction , named after its discoverer  Stanislao Cannizzaro , is a  chemical reaction  that involves the  base -induced  disproportionation   of two molecules of a non- enolizable   aldehyde   to give a  primary alcohol   and a  carboxylic acid . CANNIZZARO REACTION BY – VISHAL SINGH SOLANKI

13. Mechanism Step 1 A nucleophile such as a hydroxide ion is used to attack the carbonyl group of the given aldehyde, causing a disproportionation reaction and giving rise to an anion carrying 2 negative charges. MECHANISM OF CANNIZZARO REACTION BY – VISHAL SINGH SOLANKI

14. Mechanism Step 2 This resulting intermediate can now function as a hydride reducing agent. Due to its unstable nature, the intermediate releases a hydride anion. This hydride anion proceeds to attack another aldehyde molecule. Now, the doubly charged anion is converted into a carboxylate anion and the aldehyde is converted into an alkoxide anion. CONTI… BY – VISHAL SINGH SOLANKI

15. Mechanism Step 3 In this final step, water offers a proton to the alkoxide anion which gives rise to the final alcohol product. The reaction can proceed since the alkoxide is more basic than water. Now, the carboxylate ion gives rise to the final carboxylic acid product when acid workup is used (the acid workup is required since carboxylate is less basic than water and therefore cannot obtain a proton from water). CONTI… BY – VISHAL SINGH SOLANKI

16. CONTI… BY – VISHAL SINGH SOLANKI

17. Aldehydes with alpha hydrogen atoms undergo deprotonation due to the strongly alkaline conditions of the reaction, leading to enolates and/or aldol reactions of these enolates were beta-hydroxy aldehydes or ketones are obtained. Therefore, it is not surprising that the reaction produces only 50% of the required alcohol and  carboxylic acid   at ideal conditions. This is why the crossed Cannizzaro reaction is more commonly used. A sacrificial aldehyde is combined with a more valuable chemical and formaldehyde is used as a reductant, oxidizing it to sodium formate . The required alcohol is obtained from the reduction of the other aldehyde chemical. Since 2 different aldehydes can be completely converted into the required product, the yield of the valuable chemical is increased. CROSSED CANNIZZARO REACTION BY – VISHAL SINGH SOLANKI

18. CONTI… BY – VISHAL SINGH SOLANKI

19.   Benzoin condensation reaction can be defined as the reaction between two kinds of aromatic aldehydes especially benzaldehyde, in the presence of some catalyst (either nucleophile or heterocyclic) to form an aromatic parent compound. Condensation reactions are mainly used to create carbon to carbon bonds,  polymers , new monomers, production of polypeptides, etc. The benzoin condensation reaction is nothing but the coupling reaction that occurs between aldehydes for the formation of parent benzoin. In this case, the benzaldehyde is involved in this homocoupling process. BENZOIN CONDENSATION BY – VISHAL SINGH SOLANKI

20. CONTI… BY – VISHAL SINGH SOLANKI

21. Step 1: Formation of a Cyanohydrin Step 2: Formation of a Nucleophiles from the Cyanohydrin Step 3: Reaction of the New Nucleophile with the Second Equivalent of Benzaldehyde Step 4: Regeneration of the Catalyst MECHANISM OF BENZOIN CONDENSATION BY – VISHAL SINGH SOLANKI

22. MECHANISM OF BENZOIN CONDENSATION BY – VISHAL SINGH SOLANKI

23. EXAMPLE OF BENZOIN CONDENSATION BY – VISHAL SINGH SOLANKI

24. The  Perkin reaction  is an  organic reaction   developed by  English   chemist   William Henry Perkin  that is used to make  cinnamic acids . It gives an α,β-unsaturated aromatic acid by the  aldol condensation   of an  aromatic   aldehyde   and an  acid anhydride , in the presence of an alkali salt of the acid. The alkali salt acts as a  base   catalyst , and other bases can be used instead. One notable application for the Perkin reaction is in the laboratory synthesis of the  phytoestrogenic   stilbene   resveratrol . PERKIN CONDENSATION BY – VISHAL SINGH SOLANKI

25. MECHANISM OF PERKIN CONDENSATION BY – VISHAL SINGH SOLANKI

26. THANK YOU FOR WATCHING BY – VISHAL SINGH SOLANKI