Hydrochloric Acid → HCID 178524411, compound

HRID 1087915Notes

Reaction equation

HRID 1087915 reaction equation
[OH:1][C:2]1[N:10]=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[ClH:11].OO>>[Cl:11][C:8]1[CH:9]=[N:10][C:2]([OH:1])=[C:3]([CH:7]=1)[C:4]([OH:6])=[O:5]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 784Hydrogen PeroxideHCID 178418543HCID 178418543, compound

Product 1

HCID 178524411HCID 178524411, compoundYield 32.2%

Procedure

To a solution of 42.5 g (0.3 mole) of 2-hydroxynicotinic acid in 212.5 ml of 37% hydrochloric acid (0.3 mole) was added dropwise 46 ml of a 30% aqueous solution of hydrogen peroxide (0.45 mole) at 25°±3° C. using an ice bath to control the temperature over a 10 minute period. The mixture was seeded with crystals from a previous trial. After 5-10 min. some crystals developed and after 1.5 hr precipitate was collected and rinsed three times with water and dried to give 16.75 g (Fraction 1) (32% yield) of crude 5-chloro-2-hydroxynicotinic acid containing 5-7% starting 2-hydroxynicotinic acid and some 3,5-dichloro-2-hydroxypyridine. After about 4 hr total time from the start, an additional 23 ml of 30% hydrogen peroxide was added to the mother liquor at 25°-30° C. At the 5th hour another 23 ml (0.22 mole) of 30% hydrogen peroxide was added. The solid was then collected and rinsed with water and dried to give 3.77 g (Fraction 2) (7.6% of yield) of crude 5-chloro-2-nicotinic acid containing 10-20% 3,5-dichloro-2-hydroxypyridine and a trace of starting material. The mother liquor was stirred overnight. No new precipitate was present. The mother liquor was then combined with rinsings from Fractions 1 and 2 and the resulting solution was extracted 3 times with methylene chloride. The combined methylene chloride layers were back washed with water, dried and evaporated to give 5.5 g of solid (Fraction 3). Analysis of Fraction 3 by 1HNMR gave many signals. Chemical Ionization Mass Spectroscopy analysis showed compounds m/e 214, 216, 218, 220 corresponding to compounds with multiple (2-3) halogen atoms on pyridine ring. For the trial as a whole, the total yield of 5-chloro-2-hydroxynicotinic acid was about 35% of theory considering the impurities and yield of polychlorinated impurities was about 10% on a theoretical mole base.

Workup

  1. customover a 10 minute
  2. customprecipitate was collected
  3. washrinsed three times with water
  4. customdried

Sources & evidence

ORD record
ord-ddb728fb441b402c88df75fa6ebdfa6e
Source dataset
uspto-grants-1990_10
Patent number
US04960896

Reaction notes

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