合成路线1

Aldol condensation of acetophenone (I) with 3-nitrobenzaldehyde (II) in the presence of sodium methoxide in methanol at room temperature afforded enone (III). Double bond hydrogenation over Pd/C in MeOH-THF, with simultaneous nitro group reduction and O-benzyl hydrogenolysis, provided hydroxy ketone (IV). This compound was acylated with acetyl chloride in the presence of triethylamine and catalytic dimethylaminopyridine(DMAP) to yield ester-amide (V), which was cyclized to chromenone (VI) on treatment with NaH in DMSO, followed by HCl in refluxing acetic acid (1). Acidic hydrolysis of amide (VI) gave amine (VII), and this was treated with triflic anhydride and triethylamine to afford the corresponding sulfonamide (VIII). Demethylation of ether (VIII) with HBr in acetic acid gave phenol (IX), and then alkylation with with 2-(chloromethyl)-5-fluorobenzothiazole (X) yielded (XI). Reduction of chromenone with L-Selectride(R) in THF at -78 C gave racemic chromanone (XII) with trans stereochemistry.