Formaldehyde → HCID 9823511, compound

Participants

Reaction Steps

37-40% Aqueous formaldehyde solution (12.4 ml) was added to a solution of 1-(1,4-benzodioxan-5-yl)piperazine (33.1 g; prepared in a similar manner to that described in Example 2 above) in absolute ethanol (250 ml) and the mixture stirred at ambient temperature for 3 hours. The mixture was diluted with absolute ethanol (500 ml) and the resulting solution stirred at ambient temperature for 19 hours. A solution of 3-amino-2-methyl-1-phenyl-3-pyrazolin-5-one (31.7 g) in absolute ethanol (1000 ml) was added and the solution stirred at ambient temperature for 23 hours. The resulting solid was collected by filtration, dried in vacuo at ambient temperature, and suspended in ethyl acetate (1200 ml). The mixture was stirred and heated under reflux for 66 hours, and the resulting solid was collected by hot filtration, dried in vacuo at ambient temperature, ground with a mortar and pestle then again stirred and heated under reflux with ethyl acetate (1700 ml) for 46 hours. The product was collected by hot filtration, then dried in vacuo at ambient temperature to give 3-amino-4-[4-(1,4-benzodioxan-5-yl)piperazin-1-ylmethyl]-2-methyl-1-phenyl-3-pyrazolin-5-one as a white solid (50.4 g), m.p. 223-224° C.

Provenance & Evidence