Trifluoroacetic acid → 2-Tetralone

HRID 1758791Notes

Reaction equation

HRID 1758791 reaction equation
Br[C:2]1[C:11](OC)=[C:10]2[C:5]([CH2:6][CH2:7][CH:8]3[O:14][CH:9]32)=[C:4](OC)[CH:3]=1.FC(F)(F)C(O)=O.CCCCCC.C(OCC)(=O)C>C(Cl)(Cl)Cl>[CH2:7]1[C:8](=[O:14])[CH2:9][C:10]2[C:5](=[CH:4][CH:3]=[CH:2][CH:11]=2)[CH2:6]1

Participants

5

Reactant 3

HCID 6422Trifluoroacetic acidHCID 15916417HCID 15916417, compoundHCID 21226206Ethyl acetate hexane

Product 1

HCID 682662-TetraloneYield 98.9%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

To a solution of epoxide (2C) (0.494 g, 1.73 mmol) in 7 ml of chloroform was added 3.5 ml of trifluoroacetic acid. The solution was refluxed for 2 hrs. under argon, and then allowed to stand at room temperature overnight. The solution was once again refluxed for 1 hr. and then allowed to cool to room temperature. Washing the solution with 10 ml of water, drying over sodium sulfate, and evaporating the solvent yielded a yellow oil. Subjecting the product to medium pressure liquid chromatography using hexane-ethyl acetate::7.:3 yielded 0.250 g (51%) of the β-tetralone 44:mp 88°-89° C. 1H NMR (CDCl3) δ2.43 (2H, t, J=6 Hz,ArCH2CH2CO), 2.96, (2H, t, J=6 Hz, ArCH2CH2), 3.50 (2H, ArCH2CO,s), 3.70 (3H, s, ArOCH3), 3.73 (3H, s, ArOCH3), 6.76 (1H, s, ArH); IR (CHCl3) 3030, 2980, 2905, 2840, 2400, 2250, 1780, 1710, 1575, 1510, 1470, 1430, 1400, 1375 (sh), 1335, 1285, 1210 (br), 1170 (sh), 1140, 1080, 1040, 1010 cm-1 etc.; mass spectrum m/e/ (rel. intensity) 286 (M+ +2, 100%), 284 (M+, 100%), 271 (M+ +2-CH3. 25%), 269 (M+ -CH3, 25%), 244 (M+ +2-CH2 =C=O, 31%), 242 (M+ -CH2 =C=O, 38%), 229 (M+ +2,CH3 --CH2 =C=0, 69%), 277 (M+ -CH3 -CH2 =C=O, 69%), etc.

Workup

  1. temperatureThe solution was refluxed for 2 hrs
  2. temperatureThe solution was once again refluxed for 1 hr
  3. washWashing the solution with 10 ml of water
  4. dry with materialdrying over sodium sulfate
  5. customevaporating the solvent
  6. customyielded a yellow oil

Sources & evidence

ORD record
ord-1634f6a9fb9242dca2af3daca11900b0
Source dataset
uspto-grants-1983_02
Patent number
US04374979

Reaction notes

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