43 g of the thiourea compound (melting point 124°C) obtained in known
fashion from 2-chloro-4-methylaniline and ammonium thiocyanate and 20 cc
of methyl iodide were dissolved in 200 cc of methanol, and the solution was
refluxed for two hours.1 Thereafter, the solvent was evaporated in vacuo,
leaving 73.2 g of the isothiouronium hydroiodide of the formula as a residue.
This isothiouronium salt was admixed with 20 cc of ethylenediamine, and the
mixture was heated for about 30 minutes at 150°C to 160°C, accompanied by
stirring; methyl mercaptan escaped during that time. Subsequently, the
reaction mixture was taken up in hot dilute acetic acid, and the resulting
solution was made alkaline with 2 N sodium hydroxide. A precipitate formed,
which was separated by vacuum filtration, washed with water and dried. It
was identified to be 2-(2'-chloro-4'-methylphenyl)-amino-1,3-
diazacyclopentene-(2) having a melting point of 142°C to 145°C. The yield
was 10.2 g.
The nitrate of the base, obtained by acidifying a solution of the free base with
nitric acid, had a melting point of 162°C to 164°C and was soluble in water
and methanol.
