合成路线1

Copper-catalyzed arylation of 3-methyl-6-nitroindazole (I) with 2-bromo-6-methoxybenzoic acid (II) furnished (III). Subsequent reduction of the nitro group of (III) to (IV) was effected by transfer hydrogenation with hydrazine hydrate in the presence of Pd/C. Intramolecular cyclization of carboxylic acid (IV) in hot PPA gave rise to the pyrazoloacridine system (V). The amino group of (V) was then converted to the bromide (VI) using a Sandmeyer reaction (1). Methyl ether cleavage in (VI) with HBr in hot AcOH provided phenol (VII), which was brominated with elemental bromine at low temperature to give (VIII). A formyl group was subsequently introduced in (VIII) by treatment with dichloromethyl methyl ether and TiCl4, yielding (IX). Oxidative cleavage of aldehyde (IX) under Baeyer-Villiger rearrangement conditions furnished the diphenol compound (X). Selective acetylation of one hydroxyl group of (X) affording (XI), followed by methylation of the remaining hydroxyl afforded (XII). Benzylic bromination of the side-chain methyl group of (XII) with NBS gave the bromomethyl derivative (XIII)