2391-03-9

Disomer,White,US,1959

The S-enantimer of Brompheniramine maleate (B686355) as antihistaminic.

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.

Disomer (Schering).

Antihistaminic

Like the chlorinederivative, the antihistaminic activity of brompheniramineexists predominantly in the dextro isomer, dexbrompheniraminemaleate (D-isomer), and is of comparable potency.