Predict the products of the following reactions:
Cyclohexanone + HO-NH₂ → H⁺
Cyclohexanone reacts with hydroxylamine (HO-NH₂) in presence of acid to form cyclohexanone oxime. The carbonyl group (C=O) is converted to C=N-OH.
C₆H₅COCH₃ + NH₂-NH-NO₂ →
Acetophenone (C₆H₅COCH₃) reacts with 2,4-dinitrophenylhydrazine to form 2,4-dinitrophenylhydrazone of acetophenone. This forms a yellow/orange precipitate (2,4-DNP derivative).
R-CH=CH-CHO + NH₂-C-NH-NH₂ → H⁺
The α,β-unsaturated aldehyde (R-CH=CH-CHO) reacts with semicarbazide in presence of acid to form the corresponding semicarbazone derivative.
C₆H₅CHO + CH₃CH₂NH₂ → H⁺
Benzaldehyde (C₆H₅CHO) reacts with ethylamine (CH₃CH₂NH₂) in presence of acid to form N-ethylbenzaldimine (a Schiff base/imine).
Explanation
These reactions involve nucleophilic addition of nitrogen-containing compounds to the carbonyl group of aldehydes and ketones. Hydroxylamine forms oximes, 2,4-dinitrophenylhydrazine forms 2,4-DNP derivatives (used for characterization as mentioned in Question 8.10 context), semicarbazide forms semicarbazones (referenced in Question 8.6), and primary amines form imines (Schiff bases). All reactions occur under acidic conditions which catalyze the nucleophilic addition-elimination mechanism.