Tetrafluoroboric acid → 5-bromo-2-nitroThiazole

HRID 2085486Notes

Reaction equation

C(=O)(OC1C=CC=CC=1)N.[Br:11][C:12]1[S:16][C:15](N)=[N:14][CH:13]=1.F[B-](F)(F)F.[H+].[N:24]([O-:26])=[O:25].[Na+]>[Cu]>[Br:11][C:12]1[S:16][C:15]([N+:24]([O-:26])=[O:25])=[N:14][CH:13]=1

Participants

Conditions

Temperature: 23 °C

Procedure

Scheme 3 depicts a method for preparing compounds of formula 1 wherein R1 is ABN-. An aqueous solution consisting of 5-bromo-2-aminothiazole (6) and 20% tetrafluoroboric acid are added to an aqueous slurry of copper powder and sodium nitrite at about 0° C., followed by warming to about 23° C. Standard work-up and purification by radial chromatography afford 5-bromo-2-nitrothiazole 7. Treatment of 7 with triethylamine and ABNH hydrochloride in dimethylsulfoxide at about 60° C. affords 8. Dissolution of 8 in a solvent such as ethyl acetate and treatment with palladium on carbon and hydrogen gas (3 atmospheres) affords aminothiazole 4. The aminothiazoles thus obtained can be treated with a carboxylic acid (HO(═O)C(CR10R11)nR4), propanephosphonic acid cyclic anhydride, and triethylamine in a solvent such as ethyl acetate or dichloromethane to afford compounds of formula 1.

Workup

customStandard work-up and purification by radial chromatography

Sources & evidence

ORD record: ord-faf9f7cf3a8246f9b13bfae4624cab77
Source dataset: uspto-grants-2004_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06720427B2

Reaction notes

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