Hydrochloric Acid → Chloride 2-chloropyridinium 1-oxide

HRID 1679263Notes

Reaction equation

HRID 1679263 reaction equation
[ClH:1].N[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][N+:4]=1[O-:9].Cl.N([O-])=O.[Na+]>O>[ClH:1].[Cl:1][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][N+:4]=1[O-:9]

Participants

5

Reactant 3

HCID 313Hydrochloric Acid3×HCID 23668193Sodium NitriteHCID 178479081HCID 178479081, compound

Product 1

HCID 88478Chloride 2-chloropyridinium 1-oxide

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

The moist crystals of 2-aminopyridine-1-oxide hydrochloride from Example 1, with or without drying and recrystallization, or the material of Example 2 after purification, can be used in this preparation without substantial difference in the results. A solution of 2-aminopyridine-1-oxide hydrochloride (110 g. dry weight) and 146 g. of concentrated hydrochloric acid (37.5%) in 158 g. of water was cooled to about 0° C and treated dropwise, with stirring, with 51.8 g. of sodium nitrite in 110 g. of water over a period of 1 hour with the temperature being maintained between -5° C and +5° C, to give a clear, orange solution of diazotized material. The orange solution was stirred for about 5 minutes at about 0° C, and was then immediately added by a cooled funnel, over a 40-minute period with stirring, to a hot solution of 110 g. 20% hydrochloric acid with the temperature of the reaction vessel being maintained at 95°-101° C. After 1/3 of the diazotized solution was added, 58.5 g. concentrated hydrochloric acid (37.5%) was poured into the hot reaction mixture. The addition of the remaining 2/3 of diazotized solution was then continued at the same rate and temperature, and stirring was then continued until nitrogen evolution ceased, about 7 minutes. This treatment yielded an aqueous solution of 2-chloropyridine-1-oxide hydrochloride, suitable for use as the solution in Examples 4 and 5. Isolation by vacuum evaporation, extraction from inorganic salts with absolute ethanol and recrystallization from ethanol-toluene gave purified material, m.p. 135°-137° C.

Workup

  1. dry with materialThe moist crystals of 2-aminopyridine-1-oxide hydrochloride from Example 1, with or without drying
  2. customrecrystallization
  3. customthe material of Example 2 after purification
  4. customcan be used in this preparation without substantial difference in the results
  5. additiontreated dropwise
  6. customto give a clear, orange solution of diazotized material
  7. stirringThe orange solution was stirred for about 5 minutes at about 0° C
  8. additionwas then immediately added by a cooled funnel, over a 40-minute period
  9. stirringwith stirring, to a hot solution of 110 g
  10. additionAfter 1/3 of the diazotized solution was added
  11. additionThe addition of the remaining 2/3 of diazotized solution
  12. stirringstirring

Sources & evidence

ORD record
ord-ef7dd7ca8789414eae917e0af94f3f73
Source dataset
uspto-grants-1978_03
Patent number
US04080329

Reaction notes

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