Formaldehyde → HCID 9823511, compound

Participants

Reaction Steps

A mixture of 1-(1,4-benzodioxan-5-yl)piperazine (2.45 g), 37-40% aqueous formaldehyde solution (0.8 ml) and industrial methylated spirit (30 ml) was stirred at ambient temperature under nitrogen for 18 hours, then a slurry of 3-amino-2-methyl-1-phenyl-3-pyrazolin-5-one (1.95 g) in industrial methylated spirit (55 ml) was added in one portion. The stirred mixture was heated under reflux for 5 hours, then allowed to stand at ambient temperature for 18 hours. The resulting solid was collected by filtration, and the filtrate was concentrated in vacuo to 40 ml then cooled in ice to give a second crop of white solid which was collected by filtration. The combined solids were suspended in industrial methylated spirit (80 ml), and the mixture was heated to reflux temperature. Undissolved solid was removed by filtration of the hot mixture, then the filtrate was concentrated to 40 ml, cooled in ice, and the resulting solid was collected by filtration. The two crops of solid were combined and dried in vacuo at 65° C. to give 3-amino-4-[4-(1,4-benzodioxan-5-yl)piperazin-1-ylmethyl]-2-methyl-1-phenyl-3-pyrazolin-5-one 0.75 hydrate as a white solid (2.45 g), m.p. 222-224° C.

Provenance & Evidence