Hydrochloric Acid → ethyl 6-methyl-2-(trifluoromethyl)-2H-1-benzothiopyran-3-carboxylate

HRID 1636657Notes

Reaction equation

HRID 1636657 reaction equation
[CH3:1][C:2]1[CH:3]=[CH:4][C:5]([SH:10])=[C:6]([CH:9]=1)[CH:7]=O.[F:11][C:12]([F:21])([F:20])/[CH:13]=[CH:14]/[C:15]([O:17][CH2:18][CH3:19])=[O:16].C([O-])([O-])=O.[K+].[K+].Cl>C(OCC)(=O)C.CN(C=O)C>[CH3:1][C:2]1[CH:3]=[CH:4][C:5]2[S:10][CH:13]([C:12]([F:11])([F:21])[F:20])[C:14]([C:15]([O:17][CH2:18][CH3:19])=[O:16])=[CH:7][C:6]=2[CH:9]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 11430Potassium CarbonateHCID 5371261Ethyl (2E)-4,4,4-trifluoro-2-butenoateHCID 218836425-Methyl-2-sulfanylbenzaldehyde

Product 1

HCID 21883614ethyl 6-methyl-2-(trifluoromethyl)-2H-1-benzothiopyran-3-carboxylateYield 69.4%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 8857Ethyl AcetateSolvent

Procedure

The 5-methyl-2-mercaptobenzaldehyde (Step 1) (3.25 g, 21.3 mmol) was added to DMF (5 mL) and ethyl 4,4,4-trifluorocrotonate (4.32 g, 25.7 mmol). With stirring, K2CO3 (3.78 g, 27.3 mmol) was added causing the reaction to become a deep red. The reaction was stirred at room temperature for hours, acidified with 3N HCl, diluted with ethyl acetate and washed with water, saturated NaHCO3 solution, brine, dried over MgSO4, filtered and concentrated in vacuo yielding an oil. The oil was crystallized from diethyl ether-petroleum ether to give ethyl 6-methyl-2-(trifluoromethyl)-2H-1-benzothiopyran-3-carboxylate as a light yellow solid (4.47 g, 69%): mp 93.1-94.7° C. 1H NMR (acetone-d6/300 MHz) 7.94 (s, 1H), 7.41 (s, 1H), 7.31 (d, 1H, J=7.9 Hz), 7.25 (d, 1H, J=7.9 Hz), 4.96 (q, 1H, J=8.5 Hz), 4.33 (m, 2H), 2.34 (s, 3H), 1.35 (t, 3H, J=7.0 Hz). FABLRMS m/z 309 (M+Li).

Workup

  1. customthe reaction
  2. stirringThe reaction was stirred at room temperature for hours
  3. washwashed with water, saturated NaHCO3 solution, brine
  4. dry with materialdried over MgSO4
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customyielding an oil
  8. customThe oil was crystallized from diethyl ether-petroleum ether

Sources & evidence

ORD record
ord-b12a2ff9e22f4e4190f2cdf2223e9a13
Source dataset
uspto-grants-2000_03
Patent number
US06034256

Reaction notes

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