Treatment of 4-(acetylamino)phenylsulfonyl chloride (I) with tert-butylamine yields sulfonamide (II), which on deprotection with potassium hydroxide gives amine (III). Reaction of compound (III) with 4-methoxy-3-fluorobenz-aldehyde gives imine (IV), which is cyclized with tosylmethyl isocyanide to afford imidazole (V). Regioselective chlorination of compound (V) with N-chlorosuccinimide (NCS) to afford the chloroimidazole (VI) and then deprotection of the sulfonamide group of (VI) yields cimicoxib in 40% overall yield.

Treatment of 4-(acetylamino)phenylsulfonyl chloride (I) with tert-butylamine yields sulfonamide (II), which on deprotection with potassium hydroxide gives amine (III). Reaction of compound (III) with 4-methoxy-3-fluorobenz-aldehyde gives imine (IV), which is cyclized with tosylmethyl isocyanide to afford imidazole (V). Regioselective chlorination of compound (V) with N-chlorosuccinimide (NCS) to afford the chloroimidazole (VI) and then deprotection of the sulfonamide group of (VI) yields cimicoxib in 40% overall yield.

Treatment of 4-(acetylamino)phenylsulfonyl chloride (I) with tert-butylamine yields sulfonamide (II), which on deprotection with potassium hydroxide gives amine (III). Reaction of compound (III) with 4-methoxy-3-fluorobenz-aldehyde gives imine (IV), which is cyclized with tosylmethyl isocyanide to afford imidazole (V). Regioselective chlorination of compound (V) with N-chlorosuccinimide (NCS) to afford the chloroimidazole (VI) and then deprotection of the sulfonamide group of (VI) yields cimicoxib in 40% overall yield.