Tetrahydrofuran → tert-butyl (3'RS,4'RS)-3'-hydroxy-3',4',5',6'-tetrahydro-2'H-[2,4']bipyridine-1'-carboxylate

Temperature

50 °C

A solution of 1.30 g (5.0 mmol) of tert-butyl 3',6'-dihydro-2'H-[2,4']bipyridine-1'-carboxylate in 15 ml of absolute tetrahydrofuran was treated dropwise at 0° C. under argon with 1.0 ml (801 mg ,10.0 mmol) of borane-dimethyl sulphide complex (95%) in dimethyl sulphide. The mixture was heated to boiling such that a slow distillation of the solvent took place (about 1 drop per minute). After 3 hours 3 ml of 2N sodium hydroxide solution and 2 ml of hydrogen peroxide solution (30%) were added dropwise at 0° C. The mixture was stirred at 50° C. for 6 hours, then cooled to room temperature and, for working-up, poured into a mixture of 200 ml of ether, 200 ml of water and 25 ml of sodium pyrosulphite solution (10%) while stirring vigorously. The organic phase was separated and the aqueous phase was extracted three times with 50 ml of ether each time. The combined organic phases were washed twice with 25 ml of water each time, dried over magnesium sulphate and finally the solvent was distilled off under reduced pressure. The crude product was purified by flash chromatography on silica gel with a 1:1 mixture of hexane and ethyl acetate as the eluent. There were obtained 354 mg (24% of theory) of tert-butyl (3'RS,4'RS)-3'-hydroxy-3',4',5',6'-tetrahydro-2'H-[2,4']bipyridine-1'-carboxylate as a yellow oil; MS: 279 (M+H)+.

1. temperatureThe mixture was heated
2. distillationto boiling such that a slow distillation of the solvent
3. additionAfter 3 hours 3 ml of 2N sodium hydroxide solution and 2 ml of hydrogen peroxide solution (30%) were added dropwise at 0° C
4. temperaturecooled to room temperature
5. additionpoured into a mixture of 200 ml of ether, 200 ml of water and 25 ml of sodium pyrosulphite solution (10%)
6. stirringwhile stirring vigorously
7. customThe organic phase was separated
8. extractionthe aqueous phase was extracted three times with 50 ml of ether each time
9. washThe combined organic phases were washed twice with 25 ml of water each time
10. dry with materialdried over magnesium sulphate
11. distillationfinally the solvent was distilled off under reduced pressure
12. customThe crude product was purified by flash chromatography on silica gel with a 1:1 mixture of hexane and ethyl acetate as the eluent

ORD record

ord-fbe168ce79c9490faa1d157db16153e2

Source dataset

uspto-grants-2000_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06150526