Manufacturing Process
Pipethanate hydrochloride is dissolved in water and the solution is made alkaline by adding 10% sodium hydroxide solution. The crystals that are separated are filtered off and recrystallized from dilute ethanol. The monohydrate thereby obtained is dehydrated at 100°C under reduced pressure for 20 minutes. The products that are now in the form of a syrup due to loss of water of crystallization are further dehydrated for 2 days in a desiccator over phosphorus pentoxide whereupon the anhydrous pipethanate is obtained.
3.8 g of the anhydrous pipethanate prepared by the method described is dissolved in 15 cc of acetone, 18 g of purified ethyl bromide is added, and the mixture heated for 8 hours in a sealed tube at 100°C to 110°C. After cooling the crystals are separated and isolated by filtration. They are then washed with acetone to give 5.2 g (95.6%) of pipethanate ethylbromide with a decomposition point of 218°C to 220°C. The crystals are almost pure.
