Dimethylformamide → 2-Chloro-3-pyridinecarboxaldehyde

Temperature

-70 °C

Form a solution of lithium diisopropylamide by the adding n-butyl lithium (37.5 mL, 0.06 mol, 1.6 M in hexanes) to diisopropylamine (8.39 mL, 0.06 mol) in tetrahydrofuran (200 mL) at −10 to −20° C. under a nitrogen atmosphere. After stirring for 20 min., cool the mixture to −70° C. and add 2-chloropyridine (4.96 mL, 0.05 mol) dropwise via syringe and stir the mixture for 1 hour at this temperature. Add N,N-dimethylformamide (7.73 mL, 0.10 mol) dropwise via syringe and stir for 1 hour near −70° C. after which time remove the cooling bath and add a solution of aqueous 5N hydrochloric acid/tetrahydrofuran (5 ml125 mL) in a dropwise manner. Add water (200 mL) and warm the mixture to −10° C. Extract with ethyl acetate. Dry the combined extracts over sodium sulfate and concentrate in vacuo. Elute the resulting residue over silica gel using 10% ethyl acetate/hexanes allowing for isolation of the desired aldehyde (2.86 g, 40%) as a solid. MS(EI): (M)+ 140.2, 141.3, 143.3 m/z.

1. customat −10 to −20° C.
2. stirringstir the mixture for 1 hour at this temperature
3. customremove the cooling bath
4. additionadd a solution of aqueous 5N hydrochloric acid/tetrahydrofuran (5 ml125 mL) in a dropwise manner
5. temperatureAdd water (200 mL) and warm the mixture to −10° C
6. extractionExtract with ethyl acetate
7. dry with materialDry the combined extracts over sodium sulfate
8. concentrationconcentrate in vacuo
9. washElute the resulting residue over silica gel using 10% ethyl acetate/hexanes allowing for isolation of the desired aldehyde (2.86 g, 40%) as a solid

ORD record

ord-26e4d72c87a2406a9c123b70df9cc390

Source dataset

uspto-grants-2006_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07037921B2