Acetic Acid → 2,3-Dichloro-5-(chloromethyl)pyridine

Temperature

-5 °C

2,3-dichloro-5-trichloromethylpyridine (36.60 g, 0.139 mol) was added to a flask containing acetic acid (53.50 g, 0.892 mol) and methanol (200 mL). The mixture was cooled to −5° C., and zinc dust (20.01 g, 0.308 mol) was added in small portions at 10 minute intervals. The mixture was stirred mechanically for 4 hours, filtered, and concentrated in vacuo. The residue was dissolved in dichloromethane and washed with brine, followed by saturated aqueous sodium bicarbonate, followed by a second brine wash. The organic phase was dried over magnesium sulfate and concentrated in vacuo to yield 21.55 g (79%) of Preparatory Compound P, 2,3-dichloro-5-(chloromethyl)pyridine, as a yellow liquid (about 65% purity). 1H NMR δ 8.31 (d, 1H, J=2.3 Hz), 7.85 (q, 1H, J=0.4 Hz and J=2.2 Hz), 4.56 (s, 2H). MS (ESI) m/z 199 ([M+4]+, 8), 197 ([M+2]+, 27), 195 ([M]+, 28), 164 (11), 162 (66), 160 (100), 124 (19)

1. filtrationfiltered
2. concentrationconcentrated in vacuo
3. dissolutionThe residue was dissolved in dichloromethane
4. washwashed with brine
5. washwash
6. dry with materialThe organic phase was dried over magnesium sulfate
7. concentrationconcentrated in vacuo

ORD record

ord-2211d9c5d4294265bb7f624644d70fc3

Source dataset

uspto-grants-2009_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07557132B2