Process for the manufacture of piperazinopyrrolobenzodiazepines

Abstract From the Canadian patent

The invention concerns the manufacture of new 1,3,4,14b-tetrahydro-2H,1OH-pyrazino1,2-alpyrrolo2,1-c 1,4lbenzodlazeplnes of the formula, (I) wherein each of R1, R3 and R4 is hydrogen or lower alkyl; R2 is hydrogen, lower or higher alkyl, lower alkenyl lower, alkynyl, or (3 to 7 ring-membered cycloalkyl hydroxy, carboxy, lower carbalkoxy, carbamoyl HPh, lower alkanoyl, or HPhCO)-lower alkyl; Ph is 1,2-phenylene unsubstituted, or substituted by up to two members selected from lower alkyl, lower alkoxy, halogeno and trifluormethyl; CnH2n is lower alkylene separating both nitrogen atoms by 2 or 3 carbon atoms and R5 is hydrogen, lower alkyl lower carb-, alkoxy or hydroxy-lower alkyl; the lower …