Citric Acid → 6-Methyl-1H-pyrazolo[3,4-b]pyridine

HRID 922466Notes

Reaction equation

HRID 922466 reaction equation
Cl[C:2]1[N:9]=[C:8]([CH3:10])[CH:7]=[CH:6][C:3]=1[CH:4]=O.O.[NH2:12][NH2:13].O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(O)(=O)CC(CC(O)=O)(C(O)=O)O>>[CH3:10][C:8]1[N:9]=[C:2]2[NH:12][N:13]=[CH:4][C:3]2=[CH:6][CH:7]=1

Participants

5

Reactant 4

HCID 311Citric AcidHCID 24654Hydrazine hydrate (1:1)HCID 521998p-Toluenesulfonic acid monohydrateHCID 138491392-Chloro-6-methylpyridine-3-carbaldehyde

Product 1

HCID 552533026-Methyl-1H-pyrazolo[3,4-b]pyridine

Conditions

Temperature
130 °C

Procedure

to a mixture of 2-chloro-6-methylnicotinaldehyde (5.0 g) and hydrazine monohydrate (6.24 mL) was added para-toluenesulfonic acid monohydrate (3.67 g), and the mixture was stirred at 130° C. for 18 hours. The reaction solution was cooled, and then thereto was added 10% aqueous citric acid solution, and the mixture was stirred at room temperature for 30 minutes. The reaction solution was extracted with ethyl acetate, and washed with saturated saline. The organic layer was dried over sodium sulfate, and then concentrated under reduced pressure to give 6-methyl-1H-pyrazolo[3,4-b]pyridine [REx(104-1)] (3.61 g) as a brown powder.

Workup

  1. temperatureThe reaction solution was cooled
  2. stirringthe mixture was stirred at room temperature for 30 minutes
  3. extractionThe reaction solution was extracted with ethyl acetate
  4. washwashed with saturated saline
  5. dry with materialThe organic layer was dried over sodium sulfate
  6. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-9f177475d6af418da6c1b273c54f36b4
Source dataset
uspto-grants-2016_03
Patent number
US09278944B2

Reaction notes

Loading…