Trifluoroacetic acid → 2-Amino-5-bromo-3-hydroxypyridine

HRID 2181144Notes

Reaction equation

HRID 2181144 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[O:10][CH:9]=[N:8][C:5]2=[N:6][CH:7]=1.FC(F)(F)C(O)=O>[Pd].C(O)=O>[Br:1][C:2]1[CH:3]=[C:4]2[O:10][CH:9]=[N:8][C:5]2=[N:6][CH:7]=1.[NH2:8][C:5]1[C:4]([OH:10])=[CH:3][C:2]([Br:1])=[CH:7][N:6]=1

Participants

6

Reactant 2

HCID 6422Trifluoroacetic acidHCID 219640536-Bromo-[1,3]oxazolo[4,5-b]pyridine

Product 2

HCID 116940412-Amino-5-bromo-3-hydroxypyridineHCID 219640536-Bromo-[1,3]oxazolo[4,5-b]pyridine

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 284Formic AcidSolvent

Procedure

In another example, 6-bromooxazolo[4,5-b]pyridine can be subjected to palladium-catalyzed coupling and deprotection of the resulting intermediate with trifluoroacetic acid. 6-Bromooxazolo[4,5-b]pyridine can be produced from 2-amino-5-bromo-3-pyridinol by condensation with formic acid or a trialkyl orthoformate, using methodology similar to that of Viaud et al., Heterocycles 41: 2799 (1995). The use of other carboxylic acids produces 2-substituted-6-bromooxazolo[4,5-b]pyridines, which are also substrates for the Heck and Sonogashira reactions. The synthesis of 2-amino-5-bromo-3-pyridinol proceeds from furfurylamine (Aldrich Chemical Company). Thus, 5-bromo-3-pyridinol (produced from furfurylamine according to U.S. Pat. No. 4,192,946) can be chlorinated, using methods described by Koch et al., Synthesis, 499 (1990), to give 2-chloro-5-bromo-3-pyridinol, which in turn can be converted to 2-amino-5-bromo-3-pyridinol by treatment with ammonia.

Sources & evidence

ORD record
ord-ab7e32850913420ebecfa2998ffef343
Source dataset
uspto-grants-2005_05
Patent number
US06890935B2

Reaction notes

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