British Patent 1,040,736
EXAMPLE 1
2.3 g of para-hydroxynorephedrine are dissolved in 5 ml of water to which are added 25 ml of NH4OH (d=0.90). A solution of 5.78 g of iodine in 50 ml of 95% ethanol is added, while stirring, over a period of 45 min. The formed 1-(4-hydroxy-3,5-diiodo-phenyl)-2-aminopropanol becomes insoluble in the course of the reaction. The precipitate, separated out by filtration, is washed with cold distilled water and then purified by dissolving it in a sodium hydroxide solution followed by precipitation by means of a current of CO2 to give the product in the form of the free base, mp 212°C.
EXAMPLE 2
4.35 g (20 millimoles) of para-hydroxyephedrine hydrochloride are dissolved in 50 ml of distilled water to which 140 ml of NH4OH are added (d=0.90). A solution of 11.43 g (90 millimoles) of iodine in 150 ml of 95% ethanol is added, while stirring, over a period of time of 45 min. The 1-(4-hydroxy-3,5-diiodophenyl)-2-(methylamino)-propanol becomes insoluble in the course of the reaction. The precipitate, which is separated out by filtration, is washed with cold distilled water and then purified by dissolving it in a sodium hydroxide solution followed by precipitation by means of a current of CO2. mp 186°C.