Hydrochloric Acid → 1H-Pyrazolo[3,4-b]quinoline

HRID 1655882Notes

Reaction equation

HRID 1655882 reaction equation
O.[NH2:2][NH2:3].C1O[CH:7]([C:8]2[C:9](I)=[N:10][C:11]3[C:16]([CH:17]=2)=[CH:15][CH:14]=[CH:13][CH:12]=3)OC1.C(N(CC)CC)C.Cl>CO>[NH:2]1[C:9]2=[N:10][C:11]3[C:16]([CH:17]=[C:8]2[CH:7]=[N:3]1)=[CH:15][CH:14]=[CH:13][CH:12]=3

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8471TriethylamineHCID 24654Hydrazine hydrate (1:1)HCID 11347989Quinoline, 3-(1,3-dioxolan-2-yl)-2-iodo-

Product 1

HCID 113211981H-Pyrazolo[3,4-b]quinoline

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Hydrazine hydrate (10 g, 0.20 mol) is added dropwise to a suspension of 2-iodoquinoline-3-carboxaldehyde ethylene ketal (65.5 g, 0.20 mol), (0. Meth-Cohn, J. Chem. Soc., Perkin I, 2509 (1981), m.p. 104.5°-106.5° C. in methanol (250 mL) containing triethylamine 28 mL) at reflux. After refluxing overnight additional hdyrazine hydrate (10 g) is added and the mixture is stirred at reflux for another six and one-half hours. Concentrated hydrochloric acid (75 mL) is then added dropwise, while the mixture is refluxing and the reaction continued for one hour. The reaction mixture is cooled, poured onto ice and allowed to stand for two days. A red solid is removed by filtration and the filtrate is concentrated by rotary evaporation to remove methanol. The remaining solution is adjusted to pH 9 with concentrated ammonium hydroxide and the cream colored precipitate is filtered, washed with water and air dried. Recrystallization from ethanol gives an analytical sample, melting point 207°-208° C., calcd. for C10H 7 N3 :C, 70.99; H, 4.17; N, 24.84. Found: C, 70.82: H, 4.06: N, 24.18.

Workup

  1. temperatureat reflux
  2. additionis added
  3. temperatureat reflux for another six and one-half hours
  4. temperatureis refluxing
  5. temperatureThe reaction mixture is cooled
  6. additionpoured onto ice
  7. waitto stand for two days
  8. customA red solid is removed by filtration
  9. concentrationthe filtrate is concentrated by rotary evaporation
  10. customto remove methanol
  11. filtrationthe cream colored precipitate is filtered
  12. washwashed with water and air
  13. customdried
  14. customRecrystallization from ethanol
  15. customgives an analytical sample, melting point 207°-208° C., calcd

Sources & evidence

ORD record
ord-64c018e49aa74a689e6f0f4b74a7d726
Source dataset
uspto-grants-1993_10
Patent number
US05252538

Reaction notes

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