Ammonia → 1-(1-(4-chloro-3-methoxyphenyl)piperidin-4-yl)-2-(5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl)ethanamine

A mixture of 1-(1-(4-chloro-3-methoxyphenyl)piperidin-4-yl)-2-(5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl)ethanone (941 mg, 2.263 mmol), ammonia (5.7 mL of a 2.0 M solution in EtOH, 11.31 mmol) and titanium(IV) isopropoxide (1.34 mL, 4.53 mmol) was stirred at RT in a tightly stoppered flask for 16 h. At the conclusion of this period, the mixture was treated with anhydrous 1,2-DCE (2 mL), cooled in an ice bath and then treated with sodium borohydride (128 mg, 3.39 mmol) in portions. After 45 min, the mixture had changed to a thick foamy mixture. As a result, 1,2-DCE (3 mL) was added to facilitate stirring and the reaction was stirred for an additional 2 h. After this time, the mixture was poured into aqueous concentrated NH4OH (5 mL), diluted with CH2Cl2 (115 mL) and stirred vigorously for 30 min before being filtered through Celite. The filtrate was placed in a separatory funnel and the phases separated. The aqueous phase was extracted with CH2Cl2 (3 times). The combined extracts were washed with brine, dried (MgSO4) and concentrated to give the crude product. The crude product was purified by flash chromatography on silica gel using EtOAc and 5% MeOH/CH2Cl2 as eluents to provide 1-(1-(4-chloro-3-methoxyphenyl)piperidin-4-yl)-2-(5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl)ethanamine (490 mg, 1.175 mmol, 51.9% yield) as a pale yellow solid. 1H-NMR (400 MHz, CDCl3) δ ppm 7.18 (1 H, d, J=8.79 Hz), 6.50 (1 H, d, J=2.42 Hz), 6.41-6.47 (1 H, m), 6.30 (1 H, s), 4.22 (1 H, dd, J=13.84, 3.52 Hz), 3.91-3.99 (1 H, m), 3.87 (3 H, s), 3.69 (2 H, d, J=8.57 Hz), 3.22-3.28 (1 H, m), 2.65-2.75 (2 H, m), 2.33 (3 H, s), 1.89-1.98 (1 H, m), 1.84 (1 H, d, J=9.67 Hz), 1.53-1.63 (3 H, m).

1. temperaturecooled in an ice bath
2. waitAfter 45 min
3. stirringto facilitate stirring
4. stirringthe reaction was stirred for an additional 2 h
5. stirringstirred vigorously for 30 min
6. filtrationbefore being filtered through Celite
7. customThe filtrate was placed in a separatory funnel
8. customthe phases separated
9. extractionThe aqueous phase was extracted with CH2Cl2 (3 times)
10. washThe combined extracts were washed with brine
11. dry with materialdried (MgSO4)
12. concentrationconcentrated
13. customto give the crude product
14. customThe crude product was purified by flash chromatography on silica gel

ORD record

ord-9beb565ed7634ce5958a12874cb94ad7

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08354432B2