A typical pathway for the preparation of the title compound is depicted. Slight modifications are possible according to the patent literature.
Acylation of 4-iodoaniline (I) with 3,4-dimethoxybenzenesulfonyl chloride (II), followed by basic methanolysis leads to sulfonamide (III). Heck coupling of aryl iodide (III) with acrylic acid (IV) in the presence of tris(dibenzylideneacetone)dipalladium and tri(o-tolyl)phosphine gives the cinnamic acid derivative (V). This is then coupled to the tetrahydropyranyl-protected hydroxylamine (VI) by means of EDC/HOBt to furnish (VII). The tetrahydropyranyl hydroxamate (VII) is finally deprotected under acidic conditions to produce the title compound.
In a different method, p-aminocinnamic acid (I) is acylated by 3,4-dimethoxybenzenesulfonyl chloride (II) to yield sulfonamide (III). After activation of the carboxylic acid (III) with oxalyl chloride, the resultant acid chloride (IV) is condensed with hydroxylamine to furnish the target hydroxamic acid.