1-Methylpiperazine → 1-Methylpiperazine hydrochloride

Participants

Reaction Steps

14.9 g of 4-chloroacetyl-9,10-dihydro-4H-thieno[3,4-b][1,5]benzodiazepin-10-one, 21 g of N-methylpiperazine and 70 ml of dioxane are stirred at 80° C. for 1 hour, and the obtained solution is concentrated to dryness in vacuo. 150 ml of isopropanol and 40 ml of water are added to the resulting residue, and 25 ml of concentrated hydrochloric acid are then added dropwise; the thus prepared mixture is cooled in an ice-bath, and 9,10-dihydro-4-[(4-methylpiperazin-1-yl)acetyl]-4H-thieno[3,4-b][1,5]benzodiazepin-10-one dihydrochloride is obtained as a mixture 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 extracted exhaustively by shaking it with chloroform, and the organic solution is dried and concentrated to dryness in vacuo. 16 g of 9,10-dihydro-4-[(4-methylpiperazin-1-yl)acetyl]-4H-thieno[3,4 -b][1,5]benzodiazepin-10-one, m. 177° to 178° C. (from acetone), are thus obtained.

Provenance & Evidence