1,2-Pyrrolidinedicarboxylic acid, 1-(1,1-dimethylethyl) ester, (2S)- → 1-[(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-2-hydroxybutyl]-4-[(S)-3,5-dimethyl-4-(N-tert-butoxycarbonylpyrrolidine-2-carbonyloxy)benzyl]-1H-[1,2,4]triazol-4-ium bromide

Participants

Reaction Steps

To a solution of 3 g of 3,5-dimethyl-4-hydroxybenzyl bromide in CH3CN(30 mL) was added 1.2 g of (1R,2R)-4-[2-[2-(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-[1,2,4]triazol-1-yl-propyl]thiazol-4-yl]benzonitrile and stirring was continued for 2 h at room temperature. The precipitate was filtered and washed with ether to give 1.37 g(81 %y.) of 1-[(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-2-hydroxybutyl]-4-(3,5-dimethyl-4-hydroxy)benzyl-1H-[1,2,4]triazol-4-ium bromide(RoO9-3846) as a white solid. To a mixture of 30 g of 1-[(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluoro-phenyl)-2-hydroxybutyl]-4-(3,5-dimethyl-4-hydroxybenzyl)-1H-[1,2,4]triazol-4-ium bromide, 10.9 g of Boc-(L)-proline and 2.8 g of N,N-dimethylaminopyridine in 1.2L of dichloromethane was added 17.6 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and the mixture was stirred for 1.5 h at room temperature and concentrated in vacuo. The residue was chromatographed on silica gel (Wakogel C-200, solvent: CH2Cl2 /MeOH=14/1) to give 30.9 g(79%y.) of 1-[(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-2-hydroxybutyl]-4-[(S)-3,5-dimethyl-4-(N-tert-butoxycarbonylpyrrolidine-2-carbonyloxy)benzyl]-1H-[1,2,4]triazol-4-ium bromide as a white solid. 30.9 g of 1-[(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-2-hydroxybutyl]-4-[(S)-3,5-dimethyl-4-(N-tert-butoxycarbonylpyrrolidine-2-carbonyloxy)benzyl]-1H-[1,2,4]triazol-4-ium bromide was stirred in 600 mL of 10% TFA-dichloromethane for 5 h at room temperature and the solvent was removed in vacuo. The residue was diluted with ether and the precipitate was washed with ether to give 1-[(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-2-hydroxybutyl]-4-[(S)-3,5-dimethyl-4-(pyrrolidine-2-carbonyloxy)benzyl]-1H-[1,2,4]triazol-4-ium bromide trifluoroacetic acid salt as a white solid.

Provenance & Evidence