Hydrochloric Acid → 1-Ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-methanol, hydrochloride

HRID 237116Notes

Reaction equation

HRID 237116 reaction equation
[CH2:1]([N:3]1[C:7]2=[N:8][CH:9]=[C:10]([C:12](OCC)=[O:13])[CH:11]=[C:6]2[C:5]([CH3:17])=[N:4]1)[CH3:2].O1CCCC1.[H-].[Al+3].[Li+].[H-].[H-].[H-].[ClH:29]>O>[ClH:29].[CH2:1]([N:3]1[C:7]2=[N:8][CH:9]=[C:10]([CH2:12][OH:13])[CH:11]=[C:6]2[C:5]([CH3:17])=[N:4]1)[CH3:2]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8028TetrahydrofuranHCID 21226445Aluminium lithium hydrideHCID 544745731-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester

Product 1

HCID 215100541-Ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-methanol, hydrochloride

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

49 g. of 1-Ethyl-3-methyl-1H-pyrazolo[3,4-b]-pyridine-5-carboxylic acid, ethyl ester (0.21 mol.) are dissolved in 250 ml. of anhydrous tetrahydrofuran. Nitrogen is passed through the flask and, while stirring and cooling with tap water, 6 g. of lithium aluminum hydride (0.16 mol.) are added in small portions keeping the reaction temperature at 20°. Stirring is continued for an additional three hours at room temperature. Then 3 N-hydrochloric acid (380 ml.) is added, while cooling the flask with ice water, and the cloudy solution is evaporated in vacuo. The residue is dissolved in 95 ml. of hot water and the solution is allowed to stand over the week-end. The crystallized product (8 g. m.p. 207°-208°) is discarded. The aqueous mother liquor is extracted with three 100 ml. portions of chloroform. The combined chloroform extracts are dried with sodium sulfate and evaporated in vacuo. The resulting oily-crystalline mass is sucked off, washed with acetonitrile and dried at 70°, yield: 10 g. (21%) of 1-ethyl-3-methyl-1H-pyrazolo-[3,4-b]pyridine-5-methanol, hydrochloride (1:1); m.p. 169°-170°. A sample recrystallized from acetonitrile melts at 170°-171°.

Workup

  1. customat 20°
  2. stirringStirring
  3. customthe cloudy solution is evaporated in vacuo
  4. dissolutionThe residue is dissolved in 95 ml
  5. extractionThe aqueous mother liquor is extracted with three 100 ml
  6. dry with materialThe combined chloroform extracts are dried with sodium sulfate
  7. customevaporated in vacuo
  8. washwashed with acetonitrile
  9. customdried at 70°
  10. customA sample recrystallized from acetonitrile melts at 170°-171°

Sources & evidence

ORD record
ord-0e036278c999476086f495de4829bd9b
Source dataset
uspto-grants-1979_06
Patent number
US04159380

Reaction notes

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