31.2 g (4-chlorophenyl)biguanidine hydrochloride and 35 ml of concentrated
formic acid were refluxed for 4 hours. The hot solution was cooled and mixed
with 200 ml of diluted hydrochloric acid. The falling crystals were filtered off.
The yield of chlorazanil was 24 g (74%). MP 258°C. tice it is usually used as hydrochloride.
