Michael addition of itaconic acid (II) to 4-tert-butylaniline (I), and further lactamization afforded pyrrolidone carboxylic acid (III). This was esterified with H2SO4 in MeOH, and the resulting methyl ester (IV) was reduced to alcohol (V) with NaBH4 in boiling tetrahydrofuran. Optical resolution of (V) was achieved by condensation with phthalic anhydride (VI) to give amide (VII), followed by coupling of the remaining carboxylic acid group of (VII) with chiral alpha-methylbenzyl amine (VIII) yielding (IX). After separation of the diastereomeric mixture (IX), hydrolysis of the phthalate ester furnished the required (S)-alcohol (X) (2). Mesylate (XI), prepared from alcohol (X) and MsCl in the presence of Et3N, was condensed with methyl 4-hydroxybenzoate (XII) to afford ether (XIII). Then, basic hydrolysis of the methyl ester of (XIII) provided the title compound.

Michael addition of itaconic acid (II) to 4-tert-butylaniline (I), and further lactamization afforded pyrrolidone carboxylic acid (III). This was esterified with H2SO4 in MeOH, and the resulting methyl ester (IV) was reduced to alcohol (V) with NaBH4 in boiling tetrahydrofuran. Optical resolution of (V) was achieved by condensation with phthalic anhydride (VI) to give amide (VII), followed by coupling of the remaining carboxylic acid group of (VII) with chiral alpha-methylbenzyl amine (VIII) yielding (IX). After separation of the diastereomeric mixture (IX), hydrolysis of the phthalate ester furnished the required (S)-alcohol (X) (2). Mesylate (XI), prepared from alcohol (X) and MsCl in the presence of Et3N, was condensed with methyl 4-hydroxybenzoate (XII) to afford ether (XIII). Then, basic hydrolysis of the methyl ester of (XIII) provided the title compound.

The Michael addition of 4-tert-butylaniline (I) with 2-methylenesuccinic acid (II) followed by cyclization gives racemic 1-(4-tert-butylphenyl)-5-oxopyrrolidine-3-carboxylic acid (III) (1), which is treated with SOCl2 and condensed with (S)(-)-1-(4-methylphenyl)ethylamine (IV) to yield a diastereomeric mixture of amides (V). The resolution of (V) by silicagel chromatography affords the (S,S)-diastereomer (VI), which is treated with N2O4 and NaOAc in CCl4 to provide 1-(4-tert-butylphenyl)-5-oxopyrrolidine-3(S)-carboxylic acid (VII). The reduction of (VII) with BH3/THF in dichloromethane gives the corresponding carbinol (VIII), which is treated with MsCl and TEA in dichloromethane to yield the mesylate (IX). The condensation of (IX) with 4-hydroxybenzoic acid methyl ester (X) by means of K2CO3 in DMF affords the corresponding phenyl ether (XI), which is finally hydrolyzed with HCl/AcOH to furnish the target compound.

The Michael addition of 4-tert-butylaniline (I) with 2-methylenesuccinic acid (II) followed by cyclization gives racemic 1-(4-tert-butylphenyl)-5-oxopyrrolidine-3-carboxylic acid (III) (1), which is treated with SOCl2 and condensed with (S)(-)-1-(4-methylphenyl)ethylamine (IV) to yield a diastereomeric mixture of amides (V). The resolution of (V) by silicagel chromatography affords the (S,S)-diastereomer (VI), which is treated with N2O4 and NaOAc in CCl4 to provide 1-(4-tert-butylphenyl)-5-oxopyrrolidine-3(S)-carboxylic acid (VII). The reduction of (VII) with BH3/THF in dichloromethane gives the corresponding carbinol (VIII), which is treated with MsCl and TEA in dichloromethane to yield the mesylate (IX). The condensation of (IX) with 4-hydroxybenzoic acid methyl ester (X) by means of K2CO3 in DMF affords the corresponding phenyl ether (XI), which is finally hydrolyzed with HCl/AcOH to furnish the target compound.