<unk>  is an alkylamine and is a part of a series of antihistamines including pheniramine (Naphcon) and its halogenated derivatives including fluorpheniramine, dexchlorphenamine (Polaramine), brompheniramine (Dimetapp), dexbrompheniramine (Drixoral), deschlorpheniramine, and iodopheniramine. The halogenated alkylamine antihistamines all exhibit optical isomerism, and<unk>  in the indicated products is racemic<unk>  maleate, whereas dexchlorphenamine is the dextrorotary stereoisomer. Synthesis There are several patented methods for the synthesis of<unk> . In one example, 4-chlorophenylacetonitrile is reacted with 2-chloropyridine in the presence of sodium amide to form 4-chlorophenyl(2-pyridyl)acetonitrile. Alkylating this with 2-dimethylaminoethylchloride in the presence of sodium amide gives γ-(4-chlorphenyl)-γ-cyano-N,N-dimethyl-2-pyridinepropanamine, the hydrolysis and decarboxylation of which lead to<unk> . Chlorpheniramine synthesis A second method boom starts from pyridine, which undergoes alkylation by 4-chlorophenylacetonitrile, giving 2-(4-chlorobenzyl)pyridine. Alkylating this with 2-dimethylaminoethylchloride in the presence of sodium amide gives<unk> . Chlorpheniramine synthesis
Chlorphenamine
Phenethylamine
Methoxyphenamine
Beclamide
Nicergoline
Phenoxypropazine
Mephentermine
Brompheniramine