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प्रश्न
How will you bring about the following conversion in not more than two steps?
Ethanol to 3-Hydroxybutanal
How will you convert the following:
Ethanol to 3-Hydroxybutanal
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उत्तर १
\[\begin{array}{cc}
\phantom{...............................................................}\ce{OH}\\
\phantom{.............................................................}|\\
\ce{\underset{Ethanal}{CH3 - CH2 - OH}->[Mild oxidation][KMnO4/dil.H2SO4]\underset{(Two molecules)}{\underset{Acetaldehyde}{CH3 - CHO}}->[dil.OH-][warm]\underset{3-Hydroxybutanal}{CHO - CH2 - CH - CH3}}\
\end{array}\]
उत्तर २
\[\begin{array}{cc}
\phantom{....................................}\ce{OH}\\
\phantom{..................................}|\\
\ce{CH3CH2OH ->[PCC] CH3CHO ->[dil NaOH][Aldol condensation] \underset{3-Hydroxybutanal}{CH3 - CH - CH2 - CHO}}
\end{array}\]
PCC = Pyridinechlorochromate
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संबंधित प्रश्न
A compound 'A' of molecular formula C2H3OCl undergoes a series of reactions as shown below. Write the structures of A, B, C and D in the following reactions :
Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as electrophile.
Describe the following:
Cross aldol condensation
Complete the synthesis by giving missing starting material, reagent or product.
\[\begin{array}{cc}
\ce{C6H5CHO}\phantom{............}\\
\phantom{........}\ce{+\phantom{......}\ce{->[dil.NaOH][\Delta]}}\phantom{...}\\
\ce{CH3CH2CHO}\phantom{............}
\end{array}\]
Write chemical equations of the following reaction :
Benzoyl chloride is hydrogenated in the presence of `"Pd"/(BaSO_4)`
Compounds A and C in the following reaction are:
\[\ce{CH3CHO ->[(i) CH3MgBr][(ii) H2O] (A) ->[H2SO4, Δ] (B) ->[Hydroboration oxidation] (C)}\]
Which of the following compounds do not undergo aldol condensation?
(i) \[\ce{CH3 - CHO}\]
(ii) 
(iii) \[\begin{array}{cc}
\phantom{}\ce{O}\\
\phantom{}||\\
\ce{CH3 - C - CH3}
\end{array}\]
(iv) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]
Which of the following conversions can be carried out by Clemmensen Reduction?
(i) Benzaldehyde into benzyl alcohol
(ii) Cyclohexanone into cyclohexane
(iii) Benzoyl chloride into benzaldehyde
(iv) Benzophenone into diphenyl methane
Compound ‘A’ was prepared by oxidation of compound ‘B’ with alkaline \[\ce{KMnO4}\]. Compound ‘A’ on reduction with lithium aluminium hydride gets converted back to compound ‘B’. When compound ‘A’ is heated with compound B in the presence of \[\ce{H2SO4}\] it produces fruity smell of compound C to which family the compounds ‘A’, ‘B’ and ‘C’ belong to?
Identify A and B from the following reaction:
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{....................}\\
\phantom{}\ce{2CH3 - C = O ->[Ba(OH)2] A ->[Δ] B + H2O}
\end{array}\]
Convert the following:
Acetaldehyde to But-2-enal
\[\ce{CH3-CH2-CHO ->[dil][alkali] Product}\]
The product in the above reaction is:
The major product of the following reaction is:
Explain the aldol condensation of ethanal.
Why is the α-hydrogens of aldehydes and ketones are acidic in nature?
Assertion (A): The final product in Aldol condensation is always α, β-unsaturated carbonyl compound.
Reason (R): α, β-unsaturated carbonyl compounds are stabilised due to conjugation.
Identify A and B:
When acetaldehyde is treated with dilute NaOH, the following reaction is observed.
\[\begin{array}{cc}
\ce{2CH3 - CHO ->[dil.NaOH] CH3 - CH - CH2 - CHO}\\
\phantom{...............}|\\
\phantom{.................}\ce{OH}
\end{array}\]
- What are the functional groups in the product?
- Can another product be formed during the same reaction? (Deduce the answer by doing atomic audit of reactant and product).
- Is this an addition reaction or condensation reaction?
What is aldol condensation? Explain it with suitable examples.
