Water → Pyrazolo[1,5-a]pyridin-3-amine

HRID 859130Notes

Reaction equation

HRID 859130 reaction equation
[N+:1]([C:4]1[CH:5]=[N:6][N:7]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=12)([O-])=O.[Cl-].[Ca+2].[Cl-].O>C(O)C.[Zn]>[N:6]1[N:7]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]2=[C:4]([NH2:1])[CH:5]=1

Participants

6

Reactant 3

HCID 962WaterHCID 5284359Calcium ChlorideHCID 143613453-Nitropyrazolo(1,5-a)pyridine

Product 1

HCID 12068469Pyrazolo[1,5-a]pyridin-3-amineYield 77.2%

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 702EthanolSolvent

Procedure

To a mixture of 3-nitropyrazolo[1,5-a]pyridine (2.35 g, 14.4 mmol) and zinc (28.2 g, 432 mmol) in 78% ethanol (75.0 mL) was added a solution of calcium chloride (0.8 g, 7.2 mmol) in a minimum amount of water. The resulting mixture was refluxed for 2 h and filtered in hot and washed with hot ethanol. The filtrate was concentrated in vacuo to dryness and the residue was subjected to column chromatography (EtOAc) to give an orangish solid as the desired product (1.48 g, 77%): 1H NMR (400 MHz, CDCl3) δ 8.31 (d, J=7.0 Hz, 1H), 7.69 (s, 1H), 7.44 (d, J=9.0 Hz, 1H), 7.01–6.96 (m, 1H), 6.68–6.64 (m, 1H), 2.90 (br, 2H); MS (EI) m/z 134 (M++H).

Workup

  1. temperatureThe resulting mixture was refluxed for 2 h
  2. filtrationfiltered in hot and
  3. washwashed with hot ethanol
  4. concentrationThe filtrate was concentrated in vacuo to dryness

Sources & evidence

ORD record
ord-ed5cb388c17d477e9422cd220b3ddb7a
Source dataset
uspto-grants-2006_12
Patent number
US07151109B2

Reaction notes

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