Potassium Hydroxide → 2-Fluoro-5-hydrazinylpyridine

Temperature

0 °C

A solution of sodium nitrite (345 mg, 5.00 mmol) in water (2.5 ml) was added dropwise to a vigorously stirred solution of 6-fluoropyridin-3-amine (561 mg, 5 mmol) in 6N hydrochloric acid (5 ml) at 0° C. The mixture was stirred at 0° C. for 1 hour, then a solution of tin (II) chloride dihydrate (2.82 g, 12.5 mmol) in 6N hydrochloric acid (5 ml) was added dropwise whilst adding small pieces of ice to keep the inner temperature below 5° C. The formation of a foamy layer was observed during the addition and stirring was continued at 0° C. for 3 h. The mixture was made alkaline (pH=14) by addition of 40% aqueous solution of potassium hydroxide and extracted with ethyl acetate (5 times 15 ml). The combined organic extracts were dried over sodium sulfate, the drying agent was filtered off and the solvent was removed under reduced pressure to afford 250 mg (39%) of the target compound as a pale-yellow solid.

1. additionwhilst adding small pieces of ice
2. customthe inner temperature below 5° C
3. additionThe formation of a foamy layer was observed during the addition
4. stirringstirring
5. waitwas continued at 0° C. for 3 h
6. extractionextracted with ethyl acetate (5 times 15 ml)
7. dry with materialThe combined organic extracts were dried over sodium sulfate
8. filtrationthe drying agent was filtered off
9. customthe solvent was removed under reduced pressure

ORD record

ord-46519a903a244cdf9adc79197d8e6d62

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08163724B2