Nitric Acid → 5,7-Difluoro-3,4-dihydro-3-oxo-2H-1,4-benzothiazine-6-carboxylic acid

HRID 885682Notes

Reaction equation

HRID 885682 reaction equation
[N+:1]([C:4]1[C:5]([F:17])=[C:6]([C:12]([F:16])=[CH:13][C:14]=1F)[C:7]([O:9]CC)=[O:8])([O-])=O.FC1C=C(F)C=C(F)[C:20]=1[C:21]([O:23]CC)=O.[N+]([O-])(O)=O.O.O[S:38](O)(=O)=O>>[F:17][C:5]1[C:4]2[NH:1][C:21](=[O:23])[CH2:20][S:38][C:14]=2[CH:13]=[C:12]([F:16])[C:6]=1[C:7]([OH:9])=[O:8]

Participants

6

Reactant 5

HCID 944Nitric AcidHCID 962WaterHCID 1118Sulfuric AcidHCID 46311438Ethyl 2,4,6-trifluorobenzoateHCID 59560652HCID 59560652, compound

Product 1

HCID 595606095,7-Difluoro-3,4-dihydro-3-oxo-2H-1,4-benzothiazine-6-carboxylic acidYield 98%

Procedure

Ethyl 3-nitro-2,4,6-trifluorobenzoate. To a suspension of ethyl 2,4,6-trifluorobenzoate (3.93 g, 19.2 mmol) in conc. H2SO4 at 0° C. was added conc. HNO3 (70% HNO3) dropwise via pipet. After the addition was complete, the reaction was allowed to warm to RT and stir for 4 h. The biphasic mixture was poured into H2O and extracted with CH2Cl2 (3×). The combined organic layers were dried (Na2SO4) and concentrated to provide 4.71 g (98%) of the title compound as a yellow solid. 1H NMR (400 MHz, CDCl3): 6.96 (ddd, J=9.2, 9.2, 2.2, 1H), 4.45 (q, J=7.2, 2H), 1.40 (t, J=7.2, 3H).

Workup

  1. additionAfter the addition
  2. extractionextracted with CH2Cl2 (3×)
  3. dry with materialThe combined organic layers were dried (Na2SO4)
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-c47ac574352b42c589e820d366d751eb
Source dataset
uspto-grants-2012_08
Patent number
US08242275B2

Reaction notes

Loading…