Thionyl Chloride → Pyrazolo[1,5-a]pyrimidine-3-carbonyl chloride

HRID 418296Notes

Reaction equation

HRID 418296 reaction equation
[N:1]1[N:5]2[CH:6]=[CH:7][CH:8]=[N:9][C:4]2=[C:3]([C:10]([OH:12])=O)[CH:2]=1.S(Cl)([Cl:15])=O>>[N:1]1[N:5]2[CH:6]=[CH:7][CH:8]=[N:9][C:4]2=[C:3]([C:10]([Cl:15])=[O:12])[CH:2]=1

Participants

3

Reactant 2

HCID 24386Thionyl ChlorideHCID 1910189Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid

Product 1

HCID 19623233Pyrazolo[1,5-a]pyrimidine-3-carbonyl chlorideYield 107.2%

Conditions

Temperature
60 °C

Procedure

Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid (11.73 g, 71.9 mmol) was suspended in thionyl chloride (36 mL, 493 mmol) and heated at 60° C. for 2 h. Formation of the acyl chloride was monitored as follows: a sample of the reaction mixture was evaporated and added to MeOH and formation of the corresponding methyl ester was detected by UPLC. Then thionyl chloride was removed under reduced pressure to obtain pyrazolo[1,5-a]pyrimidine-3-carbonyl chloride (14 g) as a yellow solid.

Workup

  1. customa sample of the reaction mixture was evaporated
  2. additionadded to MeOH and formation of the corresponding methyl ester
  3. customThen thionyl chloride was removed under reduced pressure

Sources & evidence

ORD record
ord-6c8013a9a7fa4956a46e67507f5712aa
Source dataset
uspto-grants-2012_01
Patent number
US08093249B2

Reaction notes

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