Advertisements
Advertisements
प्रश्न
Write a note on Stephen reaction.
Advertisements
उत्तर
Nitriles are reduced to imine hydrochloride by stannous chloride in presence of hydrochloric acid which on acid hydrolysis give corresponding aldehydes. This reaction is called Stephen reaction.
\[\ce{\underset{(Alkane nitrile)}{R - C ≡ N +}2[H] ->[SnCl2, HCl]\underset{(Imine hydrochloride)}{R - HC = NH.HCl}->[H3O+]\underset{(Aldehyde)}{R - CHO} + NH4Cl}\]
e.g. \[\ce{\underset{(Ethanenitrile)}{H3C - C ≡ N}+2[H] ->[SnCl2, HCl][(reduction)]\underset{(Ethanimine hydrochloride)}{CH3 - HC = NH.HCl}->[H3O+]\underset{(Ethanal)}{CH3 - CHO} + NH4Cl}\]
संबंधित प्रश्न
Addition of sodium bisulphite to ethanol is ____________ type of reaction.
Write the name of the product when ketones react with 1,2-diol in presence of dry HCl.
Write a reaction to distinguish acetaldehyde from acetone.
Benzaldehyde gives all tests positive EXCEPT ____________.
The product formed after reaction between benzaldehyde and methyl magnesium iodide followed by acid hydrolysis is ____________.
Which of the following is Schiff's reagent?
Which of the following compounds does NOT undergo aldol condensation?
Which of the following represents the structure of isopropyl methyl ketone?
Compounds of general formula, are called ____________.
\[\begin{array}{cc} \phantom{...}\ce{R}\phantom{....}\ce{OR'}\phantom{}\\ \phantom{}\backslash\phantom{..}/\\ \ce{C}\\ \phantom{}/\phantom{..}\backslash\\ \phantom{...}\ce{H}\phantom{....}\ce{OR'}\phantom{} \end{array}\]
The compound which does NOT undergo haloform reaction is ____________.
Which of the following does NOT give yellow precipitate when reacted with (NaOH + I2) mixture?
Identify A, B and C.
Identify A, B, C and D.
\[\ce{ethanoic acid ->[SOCl2] A ->[Pd/BaSO4] B ->[NaOH] C ->[][\Delta] D}\]
How will you convert benzaldehyde into the following compound?
Benzophenone
What is the action of HCN on 2, 4-dichlorobenzaldehyde?
What is the action of HCN on ethanal?
Write the structure of the major product of the aldol condensation of benzaldehyde with acetone.
How will you prepare ethyl acetate from methyl acetate?
How acetone is converted into propane.
Which one of the following substituents at para-position is most effective in stabilizing the phenoxide 
ion?
A substance C4H10O yields on oxidation a compound, C4H8O which gives an oxime and a positive iodoform test. The original substance on treatment with a conc. H2SO4 gives C4H8. The structure of the compound is ______.
Which of the following is most reactive towards the addition reaction of hydrogen cyanide to form the corresponding cyanohydrin?
Which of the following is not correctly matched?
A carbonyl compound A having molecular formula C5H10O forms crystalline precipitate with sodium bisulphate and gives positive iodoform test. A does not reduce Fehling solution. Identify A.
Write the structure of the products obtained from the following ketones by action of hydrazine in presence of a slightly acidic medium.
What is the action of the following regent on propanal?
Sodium Bisulphite
How will you prepare acetic anhydride from acetic acid?
