Hydrogen Bromide → HCID 178526735, compound

HRID 2394339Notes

Reaction equation

HRID 2394339 reaction equation
NC1C=CC(F)=NC=1.Br.FC1C=CC(OC)=CN=1.Cl.[F:20][C:21]1[CH:22]=[CH:23][C:24]([OH:27])=[N:25][CH:26]=1.[N+:28]([O-])([OH:30])=[O:29]>S(=O)(=O)(O)O>[F:20][C:21]1[CH:22]=[CH:23][C:24]([OH:27])=[N:25][CH:26]=1.[F:20][C:21]1[CH:22]=[C:23]([N+:28]([O-:30])=[O:29])[C:24]([OH:27])=[N:25][CH:26]=1

Participants

9

Reactant 6

HCID 260Hydrogen BromideHCID 313Hydrochloric AcidHCID 944Nitric AcidHCID 8194405-Amino-2-fluoropyridineHCID 189731092-Fluoro-5-methoxypyridineHCID 178516119HCID 178516119, compound

Product 2

HCID 178516119HCID 178516119, compoundHCID 178526735HCID 178526735, compoundYield 53%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

5-Fluoro-2-hydroxypyridine (5-fluoro-2-pyridone) was prepared from commerially available 5-amino-2-fluoropyridine as described by Nesnow and Heidelberger (J. Heterocyclic Chem., 10, 779 (1973)) except that refluxing 48% hydrobromic acid was used to carry out the final hydrolysis of 2-fluoro-5-methoxypyridine rather than the literature conditions (25% hydrochloric acid in a sealed glass tube at 145° C.). 5-Fluoro-2-hydroxypyridine (11.16 g, 98.7 mmol) was added in portions to concentrated sulfuric acid (90 mL) at 0° C. Fuming nitric acid was then added dropwise. The reaction mixture was allowed to warm to room temperature and was then heated at 55°-60° C. for 3 hours. The mixture was cooled to room temperature and was then poured into ice/water. The yellow product was collected by filtration, washed with water and dried in the air to yield 8.24 g (53%) of the title compound. The filtrate was adjusted to pH 2 by the addition of solid NaHCO3 and was extracted with ethyl acetate. The combined extracts were dried (MgSO4) and concentrated to yield an additional amount of the title compound (1.71 g, 11%).

Workup

  1. temperaturewas then heated at 55°-60° C. for 3 hours
  2. temperatureThe mixture was cooled to room temperature
  3. filtrationThe yellow product was collected by filtration
  4. washwashed with water
  5. customdried in the air

Sources & evidence

ORD record
ord-9848542ce0b14cd789df35fc95ffa9f6
Source dataset
uspto-grants-1998_09
Patent number
US05811432

Reaction notes

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