ChEBI: The maleic acid salt of the (pharmacologically active) (S)-(+)-enantiomer of brompheniramine. A histamine H1 receptor antagonist, it is used for the symptomatic relief of allergic conditions, including rhinitis and co
junctivitis.
The following is taken from US Patent 3,061,517. Sixteen grams of racemic 3-
(2-pyridyl)-3-p-bromophenyl-N,N,-dimethylpropylamine and 9.7 grams of dphenylsuccinic acid are dissolved in 150 ml of absolute alcohol and kept at
room temperature until crystallization is effected. The crystals are filtered,washed with absolute ethyl alcohol, and recrystallized from the same solvent
using 5 ml there of per gram of solid. Three subsequent crystallizations from
80% alcohol give d-3-(2-pyridyl)-3-p-bromophenyl-N,N-dimethylpropylamined-phenylsuccinate; MP 152-154°C; [α]D25 91 (concentration, 1% in
dimethylformamide).
The free base, d-3-(2-pyridyl)-3-p-bromophenyl-N,N-dimethylpropylamine, is
obtained from this salt with diethyl ether and aqueous potassium carbonate;
[α]D25 +42.7 (concentration, 1% in dimethylformamide). The free base is then
reacted with maleic acid.
Like the chlorinederivative, the antihistaminic activity of brompheniramineexists predominantly in the dextro isomer, dexbrompheniraminemaleate (D-isomer), and is of comparable potency.
