合成路线1

3) The chlorination of 1,3-dimethoxybenzene (V) with SO2Cl2 in CHCl3 gives 1-chloro-2,4-dimethoxybenzene (VI), which is condensed with (II) by means of AlCl3 in dichloroethane yielding 5-chloro-2-hydroxy-4-methoxybenzophenone (VII). The cyclocondensation of (VII) with hydroxylamine - HCl and then with acetic anhydride - sodium acetate in refluxing DMF affords 5-chloro-6-methoxy-3-phenyl-1,2-benzoisoxazole (VIII), which is demethylated with pyridine hydrochloride at 180 C, giving 5-chloro-6-hydroxy-3-phenyl-1,2-benzoisoxazole (IX). The condensation of (IX) with dimethylamine and formaldehyde in water gives 5-chloro-7-(dimethylaminomethyl)-6-hydroxy-3-phenyl-1,2-benzoisoxazole (X), which is cyclized with (ethoxycarbonylmethyl)dimethylsulfonium bromide (XI) by means of K2CO3 in DMF, yielding 5-chloro-3-phenyl-7,8-dihydrofuro[2,3-g]-1,2-benzoisoxazole-7-carboxyli c acid ethyl ester (XII). Finally, this compound is hydrolyzed with NaOH in refluxing ethanol. 4) The condensation of isoxazole (IX) with allyl bromide by means of K2CO3 in DMF gives 6-allyloxy-5-chloro-3-phenyl-1,2-benzoisoxazole (XIII), which is rearranged with refluxing N,N-dimethylaniline yielding 7-allyl-5-chloro-6-hydroxy-3-phenyl-1,2-benzisoxazole (XIV). The cyclization of (XIV) with m-chloroperbenzoic acid (MCPBA) in refluxing CHCl3 or N-bromosuccinimide in DMSO affords 5-chloro-3-phenyl-7,8-dihydrofuro[2,3-g]-1,2-benzisoxazole-7-methanol (XV), which is finally oxidized with CrO3-H2SO4 in acetone or KMnO4 in dichloroethane. 5) The alkylation of phenol (IX) with ortho-acrylic acid trietyl ester (XXI) by means of pivalic acid in refluxing toluene gives the substituted chromane (XXIII), which is then treated with Br2 in pyridine-CHCl3 to afford ethyl ester (XII), already obtained.