Ethyl Acetate → Trifluoro-methanesulfonic acid 6-methyl-8-nitro-5-oxo-2,3-dihydro-5H-oxazolo[3,2-a]pyridin-7-yl ester

HRID 1259384Notes

Reaction equation

HRID 1259384 reaction equation
[S:1]([O:8]S(C(F)(F)F)(=O)=O)([C:4]([F:7])([F:6])[F:5])(=[O:3])=[O:2].O[C:17]1[C:18]([N+:28]([O-:30])=[O:29])=[C:19]2[O:27][CH2:26][CH2:25][N:20]2[C:21](=[O:24])[C:22]=1[CH3:23].C(OC(=O)C)C>C(Cl)Cl.CCCCCC>[CH3:23][C:22]1[C:21](=[O:24])[N:20]2[CH2:25][CH2:26][O:27][C:19]2=[C:18]([N+:28]([O-:30])=[O:29])[C:17]=1[O:8][S:1]([C:4]([F:7])([F:6])[F:5])(=[O:3])=[O:2]

Participants

6

Reactant 3

HCID 8857Ethyl AcetateHCID 67749Trifluoromethanesulfonic anhydrideHCID 583805897-Hydroxy-6-methyl-8-nitro-2H-oxazolo[3,2-A]pyridin-5(3H)-one

Product 1

HCID 58380561Trifluoro-methanesulfonic acid 6-methyl-8-nitro-5-oxo-2,3-dihydro-5H-oxazolo[3,2-a]pyridin-7-yl esterYield 20.8%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8058HexaneSolvent

Procedure

Triflic anhydride (2.78 g, 9.9 mmol) was added dropwise to a stirred solution of 7-hydroxy-6-methyl-8-nitro-2,3-dihydro-oxazolo[3,2-a]pyridin-5-one (1.5 g, 7.0 mmol) and TEA (1.42 g, 14.060 mmol) in DCM (30 mL) at −78° C. over a period of 1 hour. The resulting mixture was stirred at room temperature for 5 hours. The reaction mixture was monitored by TLC (50% ethylacetate in hexane). The reaction mixture was partitioned between DCM and water. The organic layer was washed with water, brine solution, dried over Na2SO4 and concentrated. Purification by column chromatography on silica gel (50% ethylacetate in hexane) afforded 0.5 g of the product (20.6% yield).

Workup

  1. customThe reaction mixture was partitioned between DCM and water
  2. washThe organic layer was washed with water, brine solution
  3. dry with materialdried over Na2SO4
  4. concentrationconcentrated
  5. customPurification by column chromatography on silica gel (50% ethylacetate in hexane)

Sources & evidence

ORD record
ord-fa86631f2a55403f9143502ca0a026b1
Source dataset
uspto-grants-2013_06
Patent number
US08466289B2

Reaction notes

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