合成路线1

Alkylation of 3-hydroxybenzaldehyde (I) with t-butyl bromoacetate (II) affords t butyl (3-formylphenoxy)acetate (III). Aldehyde (III) is then converted to oxime (IV) upon treatment with hydroxylamine in MeOH. Reduction of oxime (IV) to the benzylic amine (V) is carried out by catalytic hydrogenation in the presence of Raney nickel. Subsequent reductive alkylation of amine (V) with 4-t-butylbenzaldehyde (VI) furnishes the secondary amine (VII). This is then acylated by pyridine-3-sulfonyl chloride (VIII) producing sulfonamide (IX). The t-butyl ester group of (IX) is finally cleaved with trifluoroacetic acid to give the corresponding carboxylic acid.