Phentermine hydrochloride

Common Name a-benzylisopropylamine hydrochloride phenyl-tert-butylamine hydrochloride 

Trade Neme Manufacturer Country Year Introduced 

Isobutyryl chloride Ammonia Hydrogen chloride Bromine Calcium hydroxide 

Preparation of 1,3-Diphenyl-2,2-Dimethylpropanone-1 Sodamide was prepared from 12.5 grams of sodium added in small portions to 600 cc of liquid ammonia with 1 gram of hydrous ferric chloride as catalyst. The ammonia was replaced by 200 cc of dry toluene and without delay a solution of 74 grams of isobutyrophenone and 76.5 grams of benzyl bromide in 200 cc of benzene was slowly added with stirring. The reaction mixture was heated on a boiling water bath for 48 hours. Water was then added, the organic layer separated and the product isolated by distillation. The 1,3-diphenyl-2,2-dimethylpropanone-1 boiled from 142°-143°C at a pressure of 3 mm, t ° 1.5652. 

Preparation of Di-(0-Pheny/-a,a-Dimethylethyl)Urea 3.5 grams of a,a-dimethyl-(3-phenyl-propionamide in 420 cc of water was added to a solution of 87.5 grams of potassium hydroxide and 35 grams of bromine in 350 cc of water. After 2 hours at 60°C, the product was obtained on crystallization from ethanol, melting at 184°C. 

Preparation of Isobutyrophenone In a 12 liter, 3-necked flask, 1,280 grams of aluminum chloride was covered with 2,000 cc of dry thiophene-free benzene and a solution of 919 grams of isobutyryl chloride, (BP 92°-94°C) in 1 liter of benzene was added slowly with stirring. After heating for 3 hours at reflux, the solution was cooled and poured over a mixture of 1 liter of concentrated hydrochloric acid and 5 kg of ice. The benzene layer was separated, the aqueous layer extracted with benzene, and the combined benzene solutions were washed, dried and concentrated in vacuo. The residue was distilled rapidly to give 1,051 grams of isobutyrophenone, boiling at 81°-89°C at 1 mm, yield 83.4%. 

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PHENTERMINE HYDROCHLORIDE Take 8 mg 3 times/day, 30 minutes before meals, or 15 to 37.5 mg as a single daily dose before breakfast or 10 to 14 hours before retiring. 

Note. Phentermine is an isomer of methylamphetamine. Phentermine Hydrochloride... 

Infra-red Spectrum. Principal peaks at wavenumbers 730, 1285, 705, 1495,1610, 1510 (phentermine hydrochloride, KCl disk). 

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