Iodine → 3-Fluoro-4-iodopyridine-2-carbonitrile

Temperature

0 °C

To a solution of diisopropylamine (2.80 ml, 19.66 mmol) in THF (Volume: 201 ml) cooled to −78° C. was added n-butyllithium (7.86 ml, 19.66 mmol) dropwise. The dry ice/acetone bath was replaced with an ice water bath and reaction mixture was stirred at 0° C. for 25 min, and then re-cooled to −78° C. In a separate flask, a solution of 3-fluoropicolinonitrile (1.5 g, 12.29 mmol) in THF (50 mL) was cooled to −78° C., and then LDA (130 mL, 1.0 equiv) was added. The solution turned dark red. After 35 min, iodine (3.43 g, 13.51 mmol) was added rapidly. The reaction mixture was stirred for 45 min, then quenched with H2O. Layers were separated and the aqueous phase extracted with CH2Cl2 (2×). Organics combined, dried over Na2SO4, filtered, and concentrated to afford a brown residue. The crude material was dissolved in a minimal amount of CH2Cl2 to be chromatographed. Purification of the crude material by silica gel chromatography using an ISCO machine (80 g column, 60 mL/min, 0-20% EtOAc in hexanes over 23 min, tr=18 min) gave the title compound (1.7 g, 6.79 mmol, 55.2% yield) as a brown solid.

1. customreaction mixture
2. temperaturere-cooled to −78° C
3. waitAfter 35 min
4. stirringThe reaction mixture was stirred for 45 min
5. customquenched with H2O
6. customLayers were separated
7. extractionthe aqueous phase extracted with CH2Cl2 (2×)
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated
11. customto afford a brown residue
12. customto be chromatographed
13. customPurification of the crude material by silica gel chromatography
14. customan ISCO machine (80 g column, 60 mL/min, 0-20% EtOAc in hexanes over 23 min, tr=18 min)

ORD record

ord-3b5c94aec9f1436ea3dfe20730e610a8

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08969586B2