Dimethylformamide → 4,5-Dichloropyridine-3-carbaldehyde

Temperature

-40 °C

To a solution of diisopropylamine (10.73 ml, 75.9 mmol) in THF (60 ml) at −40° C., was added n-butyllithium (47.45 ml, 75.9 mmol, 1.6M in hexanes) and the solution was stirred for 15 min at −40° C., before cooling to −70° C. A solution of 3,4-dichloropyridine (10.7 g, 72.3 mmol) in THF (30 ml) was added dropwise to maintain the temperature below −65° C. The reaction was stirred at −70° C. for 2 hours before the addition of DMF (6.74 ml, 86.8 mmol). The reaction was then stirred at −40° C. for 1 hours and then allowed to warm to −5° C. before the careful addition of saturated ammonium chloride solution (50 ml) with rapid stirring over 3 min. The mixture was then partitioned between saturated ammonium chloride (150 ml) and dichloromethane (150 ml) and the layers separated. The aqueous layer was extracted with dichloromethane (2×100 ml) and the combined organic layers were dried over magnesium sulfate, then concentrated in vacuo. Purification of the resultant residue by flash chromatography (Si-PPC, dichloromethane:ethyl acetate gradient 100:0 to 94:6) afforded the title compound as white waxy solid (8.01 g, 63%).

1. temperaturebefore cooling to −70° C
2. temperatureto maintain the temperature below −65° C
3. stirringThe reaction was then stirred at −40° C. for 1 hours
4. stirringwith rapid stirring over 3 min
5. customThe mixture was then partitioned between saturated ammonium chloride (150 ml) and dichloromethane (150 ml)
6. customthe layers separated
7. extractionThe aqueous layer was extracted with dichloromethane (2×100 ml)
8. dry with materialthe combined organic layers were dried over magnesium sulfate
9. concentrationconcentrated in vacuo
10. customPurification of the resultant residue by flash chromatography (Si-PPC, dichloromethane:ethyl acetate gradient 100:0 to 94:6)

ORD record

ord-42a27b5e34a1427a9214b86bed42fd4d

Source dataset

uspto-grants-2010_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07855216B2