Thionyl Chloride → 4-Chloro-5-chloromethyl-1-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine

HRID 237111Notes

Reaction equation

HRID 237111 reaction equation
[Cl:1][C:2]1[C:7]([CH2:8]O)=[CH:6][N:5]=[C:4]2[N:10]([CH2:14][CH3:15])[N:11]=[C:12]([CH3:13])[C:3]=12.S(Cl)([Cl:18])=O>>[Cl:1][C:2]1[C:7]([CH2:8][Cl:18])=[CH:6][N:5]=[C:4]2[N:10]([CH2:14][CH3:15])[N:11]=[C:12]([CH3:13])[C:3]=12

Participants

3

Reactant 2

HCID 24386Thionyl ChlorideHCID 213152334-Chloro-1-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-methanol

Product 1

HCID 213152344-Chloro-5-chloromethyl-1-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine

Procedure

Into a three necked flask, fitted with a stirrer, reflux condenser and dropping funnel are added 94.6 g. of 4-chloro-1-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine-5-methanol (0.42 mol.) (U.S. Pat. No. 3,983,128; Example 2). While stirring 475 ml. of thionyl chloride are added dropwise within 45 minutes and the mixture is then refluxed for one and a half hours. The excess thionyl chloride is removed by a rotary evaporator and the residue is dissolved in benzene. The solvent is again removed and the remaining solid product is triturated with ligroin, filtered and dried at 70°, yield 91 g. of 4-chloro-5-chloromethyl-1-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine, which, after recrystallization from hexane, gives 83.5 g. of pure product, m.p. 96°-97°. Evaporation of the ligroin mother liquor and recrystallization of the residue gives a second crop of 5.7 g. (m.p. 95°-96°). Total yield: 89.2 g. (87%).

Workup

  1. customInto a three necked flask, fitted with a stirrer
  2. temperaturereflux condenser
  3. additionare added 94.6 g
  4. temperaturethe mixture is then refluxed for one and a half hours
  5. customThe excess thionyl chloride is removed by a rotary evaporator
  6. dissolutionthe residue is dissolved in benzene
  7. customThe solvent is again removed
  8. customthe remaining solid product is triturated with ligroin
  9. filtrationfiltered
  10. customdried at 70°
  11. customof 4-chloro-5-chloromethyl-1-ethyl-3-methyl-1H-pyrazolo[3,4-b]pyridine, which, after recrystallization from hexane
  12. customgives 83.5 g
  13. customEvaporation of the ligroin mother liquor and recrystallization of the residue
  14. customgives a second crop of 5.7 g

Sources & evidence

ORD record
ord-5c130557d48a48bfa78e5bae6fd8e848
Source dataset
uspto-grants-1979_06
Patent number
US04159380

Reaction notes

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