Diisopropylamine → Methyl 5-(3,5-dimethoxypyridin-4-yl)-5-(1,1-dimethylethylsulfinamido)pentanoate

Participants

Reaction Conditions

Reaction Steps

A cooled (−78° C.) slightly yellow solution of diisopropylamine (1.946 g; 19.23 mmol) in anh. THF (85 ml), under nitrogen, was treated dropwise with a solution of 1.6 M n-BuLi in hexanes (12.0 ml; 19.23 mmol). The resulting slightly yellow solution was further stirred at −78° C. for 20 min. A slightly yellow solution of 3,5-dimethoxypyridine (2.433 g; 17.48 mmol) in anh. THF (7 ml) was then added dropwise. The resulting yellow heterogeneous mixture was further stirred at −78° C. for 30 min. A yellow solution of methyl 5-((tert-butylsulfinyl)imino)pentanoate (4.080 g; 17.48 mmol) in anh. THF (8 ml) was then added to the cooled reaction mixture, and stirring at −78° C. was continued for 90 min. The resulting orange reaction mixture was treated successively with aq. sat. NH4Cl (29 ml), Et2O (100 ml) and water (25 ml). The separated yellow 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=20/1) afforded methyl 5-(3,5-dimethoxypyridin-4-yl)-5-(1,1-dimethylethylsulfinamido)pentanoate as a yellow oil. LC-MS (conditions B): tR=0.59 min.; [M+H]+: 373.00 g/mol.

Provenance & Evidence