1-Methylpiperazine → HCID 20549839, compound

Participants

Reaction Steps

15.0 g of 4-chloroacetyl-1,3-dimethyl-1,4,9,10-tetrahydropyrazolo[4,3-b][1,5]benzodiazepin-10-one, 21 g of N-methylpiperazine and 70 ml of dioxane are stirred at 80° C. for 1 hour (complete reaction being already indicated by a thin layer chromatogram after 20 minutes), and the thus-obtained solution is concentrated to dryness in vacuo. 150 ml of isopropanol and 40 ml of water are added to the residue, 25 ml of concentrated hydrochloric acid are then added dropwise and the resulting mixture is cooled in an icebath to obtain 1,3-dimethyl-4-[(4-methylpiperazin-1-yl)acetyl]-1,4,9,10-tetrahydropyrazolo[4,3-b][1,5]benzodiazepin-10-one dihydrochloride mixed with N-methylpiperazine hydrochloride. The hydrochlorides are dissolved in water and chloroform, the pH is adjusted to 8.2 with 2 N sodium hydroxide solution, the aqueous phase is exhaustively extracted by shaking it with chloroform and the organic solution is dried and concentrated to dryness in vacuo. This yields 17.6 g of 1,3-dimethyl-4-[(4-methylpiperazin-1-yl)acetyl]-1,4,9,10-tetrahydropyrazolo[4,3-b][1,5]benzodiazepin-10-one, mp 186° to 188° C. (from toluene); dihydrochloride, mp 222° to 224° C. (dec.); hemi fumarate, mp 257° to 258° C. (dec.).

Provenance & Evidence