NOVEL MANUFACTURE OF BENZODIAZEPINE COMPOUND

1. Process for preparing 5,11-dihydro-11-[(4-methyl-1-piperazinyl)acetyl]-6H- -pyrido[2,3-b][1,4]-benzodiazepin-6-one or the salts thereof with inorganic or organic acids, characterised in that 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one of formula I see diagramm : EP0104566,P8,F1 is reacted in a solvent conventionally used for lithiation reactions first with at least two equivalents of a lithium alkyl or lithium aryl at temperatures of between -60 and 0 degrees C and subsequently with a (4-methyl-1-piperazinyl)-acetate of general formula III see diagramm : EP0104566,P8,F2 wherein R represents an alkyl group with 1 to 10 carbon atoms, a phenyl or phenylalkyl group with 1 to 3 carbon atoms in the alkyl part, and the compound thus obtained is isolated and, if desired, converted into the salts thereof with inorganic or organic acids.