合成路线1

The acylation of 2,3-dihydrobenzofuran (I) with acetyl chloride and AlCl3 in dichloromethane gives 5-acetyl-2,3-dihydrobenzofuran (II), which by reaction with sulfur, morpholine (III) and p-toluenesulfonic acid at high temperature yields 2-(2,3-dihydrobenzofuran-5-yl)thioacetic acid morpholide (IV). The hydrolysis of (IV) with H2SO4 in refluxing water-acetic acid affords 2-(2,3-dihydrobenzofuran-5-yl) acetic acid (V), which is esterified to (VI) with ethanol and H2SO4 in refluxing toluene. The condensation of the ester (VI) with 4-(methylthio)benzoyl chloride (VII) by means of SnCl4 in refluxing dichloromethane gives ethyl 2-[7-[4-(methylthio)benzoyl]benzofuran-5-yl]acetate (VIII), which by hydrolysis with NaOH in refluxing methanol-water yields the corresponding acid (IX). Finally, this compound is dehydrogenated with N-bromosuccinimide (NBS) and dibenzoyl peroxide in refluxing CCl4.

合成路线2

Darifenacin can be obtained by three related ways: 1) The decarboxylation of (2S,4R)-4-hydroxypyrrolidine-2-carboxylic acid (I) by heating at 154 C in cyclohexanol/2-cyclohexenone gives 3(R)-hydroxypyrrolidine (II), which is N-tosylated with p-toluenesulfonyl chloride and pyridine yielding (III). The reaction of (III) with methyl p-toluenesulfonate, triphenylphosphine and diethyl azodicarboxylate (DEAD) in THF affords 1-tosyl-3(S)-(tosyloxy)pyrrolidine (IV), which is condensed with 2,2-diphenylacetonitrile (V) by means of NaH in refluxing toluene to give 2,2-diphenyl-2-[1-(p-toluenesulfonyloxy)pyrrolidin-2(S)-yl]acetonitrile (VI). Elimination of the tosyl group of (VI) with HBr and phenol in refluxing water yields 2,2-diphenyl-2-[2(S)-pyrrolidinyl]acetonitrile (VII), which by treatment with 95% H2SO4 at 100 C is converted into the corresponding acetamide (VIII). The condensation of (VIII) with 5-(chloroacetyl)-2,3-dihydrobenzofuran (IX) by means of potassium carbonate in industrial methylated spirits affords the ketonic amide (X), which is finally reduced with H2 over Pd/C in acetic acid. The intermediate 5-(chloroacetyl)-2,3-dihydrobenzofuran (IX) has been obtained by Friedel-Crafts condensation of 2,3-dihydrobenzofuran (XI) with chloroacetyl chloride by means of AlCl3 in dichloromethane. 3) The condensation of 5-(2-bromoethyl)benzofuran (XV), with the previously obtained acetamide (VIII) by means of K2CO3 in refluxing acetonitrile affords the condensation product (XVI), which is hydrogenated with H2 over Pd/C in hot acetic acid.

合成路线3