Ammonium Chloride → Ethyl 4-(2,4-dimethoxypyridin-3-yl)-4-(1,1-dimethylethylsulfinamido)-2-methylbutanoate

Temperature

-78 °C

A cooled (−78° C.) solution of commercially available 3-bromo-2,4-dimethoxypyridine (1.390 g; 5.74 mmol) in anh. THF (70 ml), under nitrogen, was treated dropwise with a solution of 1.6 M n-BuLi in hexanes (3.60 ml; 5.74 mmol). The resulting solution was further stirred at −78° C. for 15 min. A solution of ethyl 4-((tert-butylsulfinyl)imino)-2-methylbutanoate (1.290 g; 5.22 mmol) in anh. THF (5 ml) was then added to the cooled reaction mixture, and stirring at −78° C. was continued for 30 min. The resulting reaction mixture was treated successively with aq. sat. NH4Cl (35 ml), Et2O (75 ml) and water (20 ml). The separated organic layer was then washed with brine (30 ml), dried over anh. MgSO4, filtered, and concentrated to dryness under reduced pressure. Purification by FC (DCM/MeOH=30/1) afforded ethyl 4-(2,4-dimethoxypyridin-3-yl)-4-(1,1-dimethylethylsulfinamido)-2-methylbutanoate as a yellow oil. LC-MS (conditions B): tR=0.78 min. and [M+H]+: 386.68 g/mol; tR=0.80 min. and [M+H]+: 386.76 g/mol (mixture of diastereoisomers).

1. stirringstirring at −78° C.
2. waitwas continued for 30 min
3. customThe resulting reaction mixture
4. washThe separated organic layer was then washed with brine (30 ml)
5. dry with materialdried over anh. MgSO4
6. filtrationfiltered
7. concentrationconcentrated to dryness under reduced pressure
8. customPurification by FC (DCM/MeOH=30/1)

ORD record

ord-4215c71e68a3464d8800e1014729793f

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09242970B2