Water → HCID 178488146, compound

1.2 g (3.6 mmol) of 2-{[(4-chloro-3,5-dimethyl-2-pyridinyl)methyl]thio}-5-methoxy-1H-benzimidazole was mixed with toluene (40 mL). The mixture was concentrated until half the volume was left. Water (38 mg, 2.1 mmol), (S,S)-diethyl tartrate (1.85 g, 9.0 mmol) and titanium tetraisopropoxide (1.0 g, 3.6 mmol) were added in the given order while stirring. The mixture was then stirred at 50° C. for an hour and then N,N-diisopropylethylamine (0.46 g, 3.6 mmol) was added at room temperature. After 15 minutes cumene hydroperoxide (80% in cumene, 0.69 g, 3.6 mmol) was added dropwise and stirring was then continued for 2 h at room temperature. The optical purity of crude sulfoxide turned out to be 75% ee as determined by chiral HPLC analysis of the solution. The mixture was washed with water and then evaporated. The product was purified by chromatography on silica gel using methanol/dichloromethane as eluent (gradient, 1-7% MeOH) and this afforded 1.0 g of a crude product as a solid. Recrystallisation from hot acetonitrile gave 0.35 g of a white solid with an enantiomeric excess of 51%. Next, the mother liqueur from the filtration was concentrated and this material was then also recrystallised from acetonitrile to give 0.35 g of the title compound as a crystalline product with an enantiomeric excess of 92.5%.

1. concentrationThe mixture was concentrated until half the volume
2. waitwas left
3. stirringThe mixture was then stirred at 50° C. for an hour
4. stirringstirring
5. washThe mixture was washed with water
6. customevaporated
7. customThe product was purified by chromatography on silica gel
8. customRecrystallisation from hot acetonitrile

ORD record

ord-868475b01c124be182a0e8f4375d2b08

Source dataset

uspto-grants-2014_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08697880B2