Bondline / Reactions

Amide from an acyl chloride

Ammonia adds to the very electrophilic acyl chloride; the tetrahedral intermediate expels chloride, the best leaving group. A second NH₃ takes the proton.

Acyl substitution · 3 steps

Conditions

Two equivalents of NH₃ or amine (or one plus a base such as pyridine), cold.

Mechanism in 3 steps

Red curly arrows show where each pair of electrons moves.

NH3OClO−ClNH3++
Step 1Ammonia uses its lone pair to attack the carbonyl carbon.
O−ClNH3+NH2+HONH3+
Step 2The tetrahedral intermediate collapses, expelling chloride.
NH2+HONH3NH2ONH4+NH₃++
Step 3A second ammonia removes a proton from nitrogen.

About acyl substitution reactions

Carboxylic acid derivatives react by nucleophilic addition followed by elimination: the nucleophile adds to C=O, then the leaving group is expelled and the C=O reforms.

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