Hydrochloric Acid → HCID 10399928, compound

A mechanically stirred solution of 4-[(2-fluorobenzyl)amino]-3-nitropyridine (37.62 g, 152.17 mmol) in concentrated hydrochloric acid (400 mL) was heated to 90° under a nitrogen atmosphere. Stannous chloride dihydrate (174.88 g, 775.07 mmol) was added in small portions over a 20 min period. When the reaction became vigorous, the oil bath was removed until the reaction subsided. After 45 min at an increased temperature to 120° for 45 min, the reaction mixture was cooled, diluted with water (350 mL) and spin evaporated in vacuo. The residue was diluted with water (600 mL), cooled in an ice-bath and concentrated ammonium hydroxide (250 mL) was added to adjust the pH to 7-8. The solid were collected and allowed to air dry overnight. The solid cake was broken up and suspended in ethyl acetate (3×1 L). Each suspension was refluxed with the refluxing time varying from 3.5 hrs to 18 hrs. The ethyl acetate was filtered and evaporated in vacuo to yield 3-amino-2-chloro-4-[(2-fluorobenzyl)amino]pyridine (27.13 g, 71%) as an off-white solid, mp.=181°-187°. The analytical sample was prepared by essentially the same preparative method and was purified by column chromatography.

1. customthe oil bath was removed until the reaction
2. temperaturethe reaction mixture was cooled
3. additiondiluted with water (350 mL)
4. customspin evaporated in vacuo
5. additionThe residue was diluted with water (600 mL)
6. temperaturecooled in an ice-bath
7. additionconcentrated ammonium hydroxide (250 mL) was added
8. customThe solid were collected
9. customto air dry overnight
10. temperatureEach suspension was refluxed with the refluxing time
11. waitvarying from 3.5 hrs to 18 hrs
12. filtrationThe ethyl acetate was filtered
13. customevaporated in vacuo

ORD record

ord-524471feab124c3b9f1e6842c7eb7817

Source dataset

uspto-grants-1993_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05240937