合成路线1

4-Bromothiophenol (I) was alkylated with tert-butyl bromoisobutyrate (II) to give the bromoester (III). Heck reaction of (III) with vinylphthalimide (IV) produced adduct (V), which was hydrogenated in the presence of Wilkinson's catalyst to yield the arylethyl phthalimide (VI). Following phthalimide deprotection with hydrazine, the resulting primary amine (VII) was coupled with heptanoic acid using diisopropyl carbodiimide and hydroxybenzotriazole affording amide (VIII). Borane reduction of (VIII) furnished the secondary amine (IX), which was condensed with 2,4-difluorophenyl isocyanate (X) to give urea (XI). Finally, trifluoroacetic acid-promoted cleavage of the tert-butyl ester of (IX) provided the title carboxylic acid.