合成路线1

The synthesis of rofecoxib can be performed by several different ways: 1) The condensation of phenylacetic acid (I) with ethyl bromoacetate (II) by means of triethylamine in THF yields 2-(phenylacetoxy)acetic acid ethyl ester (III), which is cyclized to the hydroxyfuranone (IV) by means of potassium tert-butoxide in tert-butanol. The reaction of (IV) with triflic anhydride and diisopropylethylamine in dichloro-methane affords the corresponding triflate (V), which by reaction with LiBr in hot acetone yields the bromofuranone (VI). The condensation of (VI) with 4-(methylsulfanyl)phenylboronic acid (VII) by means of Na2CO3 and Pd(Ph3P)4 in hot toluene gives 4-[4-(methylsulfanyl)-phenyl]-3-phenylfuran-2(5H)-one (VIII), which is finally oxidized with 2KHSO5.KHSO4.K2SO4 (oxone). 2) The intermediate (VIII) can also be obtained by condensation of triflate (V) with boronic acid (VII) by means of Na2CO3 and Pd(Ph3P)4 in hot toluene. 3) The intermediate (VIII) can also be synthesized by the reaction of triflate (V) with tetramethylammonium chloride, giving the chlorofuranone (IX), which is then condensed with boronic acid (VII) as before.