Ammonium Hydroxide → 5,6-dihydro-4H-imidazo[1,2-a][1]benzazepin-4-amine

Participants

Reaction Conditions

Reaction Steps

Charge a reactor with 35.9 kg of 5,6-dihydro-4H-imidazo[1,2-a][1]benzazepin-4-amine dihydrochloride and 453 ml of water. Add 29.7 L of NH4OH 25% slowly within 30 minutes maintaining the temperature below 25° C. After the addition, the pH is 9 and is a clear brown solution. Crystallization is induced by adding 31.5 grams of seeds at 22° C. Stir the suspension for 8 hrs and cool to 5° C. Filter and wash the filter cake with 54 L of cold water and dry the resulting filter cake in the filter using N2/vacuum for 31 hrs which yields 5,6-dihydro-4H-imidazo[1,2-a][1]benzazepin-4-amine. Dissolve 29 kg of the crude filter cake in 145 L of ethanol portionwise. Remove 73 L of solvent by vacuum distillation. Add 108 L of ethanol and remove and distillation 133 L of solvent until the final concentration is 2 L/kg. Perform an in-process Karl Fischer analysis to determine the final water content at ≦0.1% w/w.

Provenance & Evidence