Diphenyl Ether → 1-ethyl-4-hydroxy-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester

HRID 329177Notes

Reaction equation

HRID 329177 reaction equation
C(O[C:4](=[O:21])[C:5](=[CH:11][NH:12][C:13]1[N:17]([CH2:18][CH3:19])[N:16]=[C:15]([CH3:20])[CH:14]=1)[C:6]([O:8][CH2:9][CH3:10])=[O:7])C.C1(OC2C=CC=CC=2)C=CC=CC=1>C(O)C>[CH2:9]([O:8][C:6]([C:5]1[C:4]([OH:21])=[C:14]2[C:15]([CH3:20])=[N:16][N:17]([CH2:18][CH3:19])[C:13]2=[N:12][CH:11]=1)=[O:7])[CH3:10]

Participants

4

Reactant 2

HCID 7583Diphenyl EtherHCID 11380881[[(1-Ethyl-3-methyl-5-pyrazolyl)amino]methylene]malonic acid diethyl ester

Product 1

HCID 1784695811-ethyl-4-hydroxy-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

14.8 g. of [[(1-ethyl-3-methyl-5-pyrazolyl)amino]methylene]malonic acid diethyl ester (0.05 mol.) are dissolved in 50 g. of diphenyl ether. The reaction mixture is heated to 235°-250° (bath temperature) and allowed to react at this temperature for 1 to 2 hours, while the resulting ethanol is continuously distilled off. The last part of the alcohol is removed by means of a water aspirator. The diphenyl ether is separated by distillation with a fractionating column in vacuo. The 1-ethyl-4-hydroxy-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester is obtained at b.p. 0.1-0.5 125°-129°, yield 10.7 g. (86%), m.p. 91°-93°. The compound is recrystallized from ligroin (90°-100°), m.p. 93°-94°.

Workup

  1. temperatureThe reaction mixture is heated to 235°-250° (bath temperature)
  2. distillationis continuously distilled off
  3. customThe last part of the alcohol is removed by means of a water aspirator
  4. customThe diphenyl ether is separated by distillation with a fractionating column in vacuo

Sources & evidence

ORD record
ord-417c16714e7349c7835b64a3e3d7512a
Source dataset
uspto-grants-1977_04
Patent number
US04020072

Reaction notes

Loading…