p-Toluenesulfonic acid → Oxazolo(4,5-b)pyridine

HRID 1796137Notes

Reaction equation

HRID 1796137 reaction equation
[NH2:1][C:2]1[C:7]([OH:8])=[CH:6][CH:5]=[CH:4][N:3]=1.[CH2:9](OC(OCC)OCC)C.C1(C)C=CC(S(O)(=O)=O)=CC=1>>[O:8]1[C:7]2[C:2](=[N:3][CH:4]=[CH:5][CH:6]=2)[N:1]=[CH:9]1

Participants

4

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 281142-Amino-3-HydroxypyridineHCID 31214Ethyl orthoformate

Product 1

HCID 10103159Oxazolo(4,5-b)pyridine

Conditions

Temperature
140 °C

Procedure

A mixture of 2-amino-3-hydroxy pyridine (25 g, 227 mmol), triethylorthoformate (75 ml) and p-toluenesulfonic acid (61 mg) was heated at 140° C. for 8 hours. Excess triethylorthoformate was removed under vacuum. The product was crystallized from ethyl acetate to yield 22.5 g of oxazolo[4,5-b]pyridine; H1NMR (DMSO-δ): 9.26 (1H, s), 8.78 (1H, d), 8.45 (1H, d), 7.7(1H, dd); MS: 120.8 (M+1).

Workup

  1. customExcess triethylorthoformate was removed under vacuum
  2. customThe product was crystallized from ethyl acetate

Sources & evidence

ORD record
ord-926a731e56534eb88193d5a0f6966cb3
Source dataset
uspto-grants-2006_04
Patent number
US07030116B2

Reaction notes

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