合成路线1

Reaction of vanillic acid (I) with 3-bromopropanol gave ether (II). Subsequent nitration of (II) with simultaneous oxidation of the primary alcohol employing nitric acid afforded the nitro diacid (IV), which by chemoselective esterification in the presence of a catalytic amount of p-toluenesulfonic acid yielded monoester (IV). After conversion of (IV) to the acid chloride upon treatment with oxalyl chloride, coupling with (S)-2-(hydroxymethyl)pyrrolidine (V) gave amide (VI). Catalytic hydrogenation of the nitro group of (VI), followed by protection of the intermediate aniline with 2,2,2-trichloroethyl chloroformate provided carbamate (VII). Further Swern oxidation of the alcohol group of (VII) with concomitant cyclization generated the pyrrolobenzodiazepine (VIII). The methyl ester of (VIII) was then hydrolyzed to carboxylic acid (IX).