The title hemiglutarate ester was synthesized by acylation of the known olivacine derivative (I) with glutaric anhydride (II) in pyridine, followed by conversion to the corresponding dihydrochloride salt.
The known pyridocarbazole (I) was methylated to (II) using dimethyl carbonate as the alkylating agent in the presence of K2CO3 and the phase-transfer catalyst adogen-464. For the preparation of the required amide (V), the ester group of (III) was first hydrolyzed with NaOH to the carboxylic acid (III), which was then coupled with 2-(dimethylamino)ethyl amine (IV) by means of (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP) in hot N-methylpyrrolidone yielding (V). Finally, cleavage of the methyl ether of (V) with BBr3 provided the title compound.