Pyridine → cis-2,6-Dimethyl-piperidine-1-carboxylic acid N'-(5-fluoro-pyridin-2-yl)-hydrazide

Temperature

45 °C

Pyridine (2.40 mL, 29.7 mmol) was added dropwise to an ice cold suspension of triphosgene (4.42 g, 14.9 mmol) in DCM (30.0 mL). cis-2,6-Dimethylpiperidine (2.00 mL, 14.9 mmol) was added and the reaction stirred for 3 hours, then quenched by dropwise addition of HCl (1M aqueous, 30 mL). The mixture was extracted into DCM (3×). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated in vacuo. The product was used in the next reaction without purification. cis-2,6-Dimethylpiperidine-carbamoylchloride (1.79 g, 10.2 mmol) was dissolved in DCM (90.0 mL) and DIPEA (2.42 mL, 13.9 mmol) was added followed by (5-fluoro-pyridin-2-yl)-hydrazine (WO 2010 022076, which is incorporated herein by reference in its entirety, 1.18 g, 9.30 mmol) and the reaction heated to 45° C. overnight. The reaction was cooled and quenched into water. The mixture was extracted into DCM (3×). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated in vacuo. The residue was purified by FCC using 0-6% [2M NH3 in MeOH] in DCM to give the title compound (1.38 g, 56%). 1H NMR (300 MHz, CDCl3): 1.29 (6H, d, J 7.1 Hz), 1.48-1.90 (6H m), 4.26 (2H, qn, J 6.9 Hz), 6.39 (1H, d, J 2.3 Hz), 6.50 (1H, d, J 2.3 Hz), 6.74 (1H, dd, J 9.0, 3.6 Hz), 7.27 (1H, ddd, J 8.9, 8.0, 2.9 Hz), 8.03 (1H, d, J 2.9 Hz).

1. customquenched by dropwise addition of HCl (1M aqueous, 30 mL)
2. extractionThe mixture was extracted into DCM (3×)
3. washThe combined organic layers were washed with brine
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. customevaporated in vacuo
7. customThe product was used in the next reaction without purification
8. temperatureThe reaction was cooled
9. customquenched into water
10. extractionThe mixture was extracted into DCM (3×)
11. washThe combined organic layers were washed with brine
12. dry with materialdried (MgSO4)
13. filtrationfiltered
14. customevaporated in vacuo
15. customThe residue was purified by FCC

ORD record

ord-93e94c6bab2d44c6892a72e743d508f0

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09139584B2