Which of the following reactions leads to the formation of a primary amine ? .

Options

A. `Et_(2)C=O+underset((DMF))HCOMe_(2)overset(Delta)rarr`
B. `PhCOCH_(3)+overset(+)NH_(4)HCO_(2)^(_)overset(Delta)rarr`
C. Cyclohexanone `+ DMFoverset(Delta)rarr`
D. All of these

Answer

B

Explanation

These reductive aminations are examples of the Leuckart reaction.
`PhCOCH_(3)+overset(+)(N)H_(4)HCbarO_(2)overset(Delta)rarrunderset(1^(@)"amine")(Phoverset(NH_(2))overset(|)(C)HCH_(3))`
`Et_(3)C-O+HCONMe_(2)overset(Delta)rarrEtunderset(3^(@)"amine")(-overset(NH_(2))overset(|)(C)H-Et)`

Aldehydes and ketones with ammonium formate or with formamide to give formy1 derivatives of primary amines (Leuckart reaction) These formy1 derivatives are readily hydrolysed by acid to the primary amine :