Hydrochloric Acid → HCID 21510053, compound

HRID 1576818Notes

Reaction equation

HRID 1576818 reaction equation
C([O:3][C:4]([C:6]1[C:7]([O:17][CH2:18][CH3:19])=[C:8]2[CH:14]=[N:13][N:12]([CH2:15][CH3:16])[C:9]2=[N:10][CH:11]=1)=O)C.[H-].[Al+3].[Li+].[H-].[H-].[H-].Cl.Cl.C(OC1C(CO)=CN=C2N(CC)N=CC=12)C>O1CCCC1.O>[CH2:18]([O:17][C:7]1[C:6]([CH2:4][OH:3])=[CH:11][N:10]=[C:9]2[N:12]([CH2:15][CH3:16])[N:13]=[CH:14][C:8]=12)[CH3:19]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 13072976Ethyl 4-ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylateHCID 21226445Aluminium lithium hydrideHCID 21510052HCID 21510052, compound

Product 1

HCID 21510053HCID 21510053, compound

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Procedure

115 g. of 4-Ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (0.438 mol.) are dissolved in 1.7 liters of anhydrous tetrahydrofuran. Nitrogen is passed through the flask and while stirring and cooling with tap water 12.5 g. of lithium aluminium hydride is added in portions in order to prevent the temperature from exceeding 22°. The mixture is stirred at room temperature for 1 hour and then at reflux temperature for 2 hours. While stirring and cooling with ice-water, 600 ml. of hydrochloric acid (3 N) is added drop by drop and the reaction mixture is allowed to stand over night. Then the clear solution is evaporated to dryness in vacuo and the residue is treated with 1.6 liters of hot absolute alcohol dissolving mainly AlCl3 and LiCl but leaving 45.3 g. of 4-ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-methanol hydrochloride (m.p. 170°-171° dec.). An additional amount of 14.1 g. of hydrochloride precipitates from the alcoholic solution. Yield 59.4 g. (52.5%). Neutralization of the hydrochloride by means of aqueous sodium hydroxide and extracting with chloroform provides the free compound, m.p. 100°-102°.

Workup

  1. temperaturecooling
  2. customfrom exceeding 22°
  3. stirringThe mixture is stirred at room temperature for 1 hour
  4. temperatureat reflux temperature for 2 hours
  5. stirringWhile stirring
  6. waitto stand over night
  7. customThen the clear solution is evaporated to dryness in vacuo
  8. additionthe residue is treated with 1.6 liters of hot absolute alcohol dissolving mainly AlCl3 and LiCl
  9. customleaving 45.3 g
  10. customof hydrochloride precipitates from the alcoholic solution
  11. extractionNeutralization of the hydrochloride by means of aqueous sodium hydroxide and extracting with chloroform
  12. customprovides the free compound, m.p. 100°-102°

Sources & evidence

ORD record
ord-a64d9f3fa4e042b4b09ab103507054af
Source dataset
uspto-grants-1976_09
Patent number
US03983128

Reaction notes

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