Chlorosulfonic acid → 3-Methyl-1-(2-pyridyl)pyrazole-4-sulfonylchloride

HRID 1638904Notes

Reaction equation

HRID 1638904 reaction equation
[Cl:1][S:2]([OH:5])(=O)=[O:3].[CH3:6][C:7]1[CH:11]=[CH:10][N:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][N:13]=2)[N:8]=1>C(Cl)(Cl)Cl>[CH3:6][C:7]1[C:11]([S:2]([Cl:1])(=[O:5])=[O:3])=[CH:10][N:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][N:13]=2)[N:8]=1

Participants

4

Reactant 2

HCID 24638Chlorosulfonic acidHCID 218123462-(3-methyl-1H-pyrazol-1-yl)pyridine

Product 1

HCID 198394923-Methyl-1-(2-pyridyl)pyrazole-4-sulfonylchloride

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Conditions

Temperature
60 °C

Procedure

To 30 ml of chlorosulfonic acid contained in 60 ml of chloroform, 30 g of 3-methyl-1-(2-pyridyl)pyrazole was added dropwise under ice-cooling, followed by stirring at 60° C. for 3 hours. To a residue obtained by evaporating chloroform under reduced pressure, 30 ml of thionyl chloride was added dropwise at about 60° C. over a period of 1 hour. After the addition, the reaction mixture was stirred at 95° C. for 30 minutes while heating under reflux. After cooling, it was poured into ice water and extracted with chloroform, organic layer was washed with water and dried, and thereafter solvent was evaporated under reduced pressure to obtain 49 g of crude 3-methyl-1-(2-pyridyl)pyrazole-4-sulfonylchloride as an oily product. The sulfonylchloride obtained was dissolved in 50 ml of tetrahydrofuran, and then was added dropwise at 0° to 10° C. to 41.4 g of t-butylamine contained in 100 ml of tetrahydrofuran. After stirring at room temperature for 1.5 hour, filtration was carried out, and filtrate obtained was concentrated to give a residue, to which ethyl acetate was added, followed by washing with diluted hydrochloric acid and drying, and then solvent was evaporated to give crystals. Crystals obtained was washed with ether to obtain 48.6 g of the title compound. m.p.: 174° to 175° C.

Workup

  1. temperaturecooling
  2. customTo a residue obtained
  3. customby evaporating chloroform under reduced pressure, 30 ml of thionyl chloride
  4. additionwas added dropwise at about 60° C. over a period of 1 hour
  5. additionAfter the addition
  6. stirringthe reaction mixture was stirred at 95° C. for 30 minutes
  7. temperaturewhile heating
  8. temperatureunder reflux
  9. temperatureAfter cooling
  10. additionit was poured into ice water
  11. extractionextracted with chloroform, organic layer
  12. washwas washed with water
  13. customdried
  14. customsolvent was evaporated under reduced pressure

Sources & evidence

ORD record
ord-18f4596cc8024a4f89ad5005ac2c370e
Source dataset
uspto-grants-1989_11
Patent number
US04881965

Reaction notes

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