Ammonia → 2-Chloro-3,4-dimethoxypyridine hydrochloride

Temperature

-78 °C

A solution of diisopropylamine (84.0 μl, 0.599 mmol) and the compound of Example B240 (860 mg, 5.99 mmol) in tetrahydrofuran (4 ml) was added to a solution of 1.06 M phenyllithium cyclopentane-diethyl ether solution in tetrahydrofuran (11 ml) cooled to −78° C. under nitrogen atmosphere. This reaction mixture was stirred at −40° C. for 1 hour, then at −18° C. for another 20 minutes. The reaction mixture was cooled again to −78° C., trimethoxyborate (2.04 ml, 18.0 mmol) was added dropwise thereto, and the resulting mixture was stirred at 0° C. for 20 minutes. At that temperature, aqueous ammonia (29%, 30 ml), ammonium chloride (4.5 g), and an aqueous hydrogen peroxide solution (30%, 12 ml) were added in this order, and the mixture was stirred at room temperature for 2 hours. Saturated sodium thiosulfate, acetic acid and ethyl acetate were added, and the mixture was washed with saturated brine. The ethyl acetate layer obtained upon filtration through silica gel was concentrated under reduced pressure. The resulting residue was treated in the same manner as in Example B231 to obtain the title compound (31.3 mg).

1. waitat −18° C. for another 20 minutes
2. temperatureThe reaction mixture was cooled again to −78° C.
3. stirringthe resulting mixture was stirred at 0° C. for 20 minutes
4. stirringthe mixture was stirred at room temperature for 2 hours
5. washthe mixture was washed with saturated brine
6. customThe ethyl acetate layer obtained upon filtration through silica gel
7. concentrationwas concentrated under reduced pressure

ORD record

ord-83e948a57ad94afe8527aba1225a893f

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07375204B2