Selenium Dioxide → 6-chloro-3-methoxy-1-trityl-1H-pyrazolo[4,3-c]pyridine-4-carbaldehyde

HRID 588090Notes

Reaction equation

HRID 588090 reaction equation
[Cl:1][C:2]1[N:7]=[C:6]([CH3:8])[C:5]2[C:9]([O:31][CH3:32])=[N:10][N:11]([C:12]([C:25]3[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=3)([C:19]3[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=3)[C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)[C:4]=2[CH:3]=1.[Se](=O)=[O:34]>O1CCOCC1>[Cl:1][C:2]1[N:7]=[C:6]([CH:8]=[O:34])[C:5]2[C:9]([O:31][CH3:32])=[N:10][N:11]([C:12]([C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)([C:19]3[CH:20]=[CH:21][CH:22]=[CH:23][CH:24]=3)[C:25]3[CH:26]=[CH:27][CH:28]=[CH:29][CH:30]=3)[C:4]=2[CH:3]=1

Participants

4

Reactant 2

HCID 24007Selenium DioxideHCID 1182721496-chloro-3-methoxy-4-methyl-1-trityl-1H-pyrazolo[4,3-c]pyridine

Product 1

HCID 1182719996-chloro-3-methoxy-1-trityl-1H-pyrazolo[4,3-c]pyridine-4-carbaldehydeYield 76%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

6-chloro-3-methoxy-4-methyl-1-trityl-1H-pyrazolo[4,3-c]pyridine (25 g, 45.5 mmol) was charged with 1,4-dioxane (200 ml) and selenium dioxide (15.13 g, 136 mmol) and heated to reflux overnight. The white slurry eventually dissolved to a dark yellow solution. TLC and LC/MS showed good conversion to product, with some SM left. The reaction was filtered through celite, washed with DCM and purified on silica gel, 10-50% EtOAc/hexanes to provide 6-chloro-3-methoxy-1-trityl-1H-pyrazolo[4,3-c]pyridine-4-carbaldehyde (15.7 g, 34.6 mmol, 76% yield).

Workup

  1. temperatureheated
  2. temperatureto reflux overnight
  3. dissolutionThe white slurry eventually dissolved to a dark yellow solution
  4. waitwith some SM left
  5. filtrationThe reaction was filtered through celite
  6. washwashed with DCM
  7. custompurified on silica gel, 10-50% EtOAc/hexanes

Sources & evidence

ORD record
ord-6ec8dd6b6d0241f2a86444a178bb8164
Source dataset
uspto-grants-2016_01
Patent number
US09226922B2

Reaction notes

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