THE PREPARATION OF GUANETHIDINE

An industrial method for the preparation of the antihypertensive drug guanethidine (Ⅷ) has been described. The manufacture of the raw material cycloheptanone (Ⅰ) via 1-nitromethylcylohexanol was accomplished by the conventional reduction by means of iron filings and hydrochloric acid. This modification gave results in overall yield (55—60% against the nitro compound) compared favourably with those obtained by the reported procedures, such as catalytic reduction or electrolytic reduction. It offers advantages of cheapness, rapidity, simplicity and industrial adaptibility. Electrolytic reduction of the appropriate thiolactam (Ⅲ) gave cycloheptamethylenimine (Ⅳ), which in turn through the Gabriel synthesis led to 2-(octahydro-1-azocinyl)ethylamine (Ⅶ).