Methanol (225 ml.) is placed in a
500-ml. two-necked flask equipped with a mechanical stirrer and a reflux condenser.
Sodium (6.8 g., 0.30 g. atom) in small pieces is dropped down the condenser into the stirred
methanol. The resultant solution is cooled to room temperature, and
64 g. (0.30 mole) of 1-phenylbiguanide hydrochloride (Note
1) is added. The mixture is stirred at room temperature for 20 minutes. The
sodium chloride that precipitates is separated on a
Büchner funnel and washed with
25 ml. of methanol.
The combined filtrates, which contain
1-phenylbiguanide as the free base, are placed in a 500
-ml. three-necked flask equipped with a mechanical stirrer, a drying tube containing calcium chloride, and a dropping funnel, and
36.8 g. (0.30 mole) of ethyl chloroacetate (Note
2) is added at room temperature with stirring. The mixture is stirred at room temperature for 14 hours, during which time
2-amino-4-anilino-6-(chloromethyl)-s-triazine precipitates as a white solid. After being separated by filtration and air-dried, the triazine weighs
37–40 g. and melts at
138–140°. The
methanol filtrate is added to 500 ml. of cold water. The mixture is cooled in an
ice bath with stirring for 2 hours and filtered to remove an additional
10–12 g. of gray triazine, m.p.
140–142°. The total yield of crude product is
47–52 g.