Method of preparation of 3, 4 - dihydroxy isopropylamino propiophenone alpha - - -

摘要

The invention comprises the compounds 2 : 4 - dihydroxy - a - isopropylaminopropiophenone, 3 : 4 - dibenzyloxy - a - isopropylaminopropiophenone, and their salts, specifically the hydrochlorides, hydrobromides and sulphates. Other salts may be formed by use of phosphoric, acetic, propionic, and benzoic acids. In the examples: (1) 3 : 4-dibenzyloxy - a - bromopropiophenone is treated with isopropylamine to give 3 : 4-dibenzyloxy-a -isopropylaminopropiophenone (isolated as the hydrobromide). The hydrochloride is obtained using hydrochloric instead of hydrobromic acid. The free base is obtained by treatment of the salt with triethanolamine and extraction with ether; (2) 3 : 4-dibenzyloxy-a -isopropylaminopropiophenone hydrobromide obtained as in example (1) is reduced in alcoholic solution in the presence of palladium on charcoal catalyst to 3 : 4-dihydroxy-a -isopropylaminopropiophenone hydrobromide which may be converted into the free base with ammonium hydroxide; (4) the sulphate of the base formed in example (3) is produced by treatment with sulphuric acid in alcoholic solution; (5) the hydrochloride of 3 : 4-dihydroxy-a -isopropylaminopropiophenone is prepared by the reduction of 3 : 4 - dibenzyloxy - a - isopropylaminopropiophenone using a palladium or charcoal catalyst. The compounds of the invention have a bronchodilator effect.