tert-Butyl piperazine-1-carboxylate → Tert-butyl 4-(3-methoxy-2,2-dimethyl-3-oxopropyl)piperazine-1-carboxylate

Temperature

0 °C

A solution of 567 (0.57 mmol, crude in 25 ml of DCM) and 1-Boc-piperazine (1.175 g, 6.31 mmol) in DCM (50 ml) was stirred for 1 h at rt under nitrogen, then cooled down to 0° C. To the cold solution NaBH(OAc)3 (4.22 g, 18.93 mmol) was added in one portion. The reaction mixture was stirred at 0° C. for 1 h, then at rt overnight, quenched by addition of water, stirred for 1 h and slowly neutralyzed with a saturated aqueous solution of sodium bicarbonate (pH=7-8). The alkaline solution was extracted with DCM. The organic extract was dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by Biotage (Snap 25 g cartridge, MeOH/DCM: 0/100 to 10/90 over 30 CV), to afford the desired product 568 (1.137 g, 3.79 mmol, 60% yield) as colorless oily liquid. MS (m/z): 301.3 (M+H).

1. customat rt overnight, quenched by addition of water
2. stirringstirred for 1 h and slowly neutralyzed with a saturated aqueous solution of sodium bicarbonate (pH=7-8)
3. extractionThe alkaline solution was extracted with DCM
4. extractionThe organic extract
5. dry with materialwas dried over anhydrous magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customThe residue was purified by Biotage (Snap 25 g cartridge, MeOH/DCM: 0/100 to 10/90 over 30 CV)

ORD record

ord-393d49bbd82746e88f035e55c787cf03

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08906852B2