Boron trifluoride etherate → 6-Methoxy-1-benzothiophene

HRID 2232339Notes

Reaction equation

HRID 2232339 reaction equation
C(O[CH:4](OCC)[CH2:5][S:6][C:7]1[CH:12]=[CH:11][CH:10]=[C:9]([O:13][CH3:14])[CH:8]=1)C.B(F)(F)F.CCOCC.C([O-])(O)=O.[Na+]>C(Cl)Cl>[CH3:14][O:13][C:9]1[CH:10]=[CH:11][C:12]2[CH:4]=[CH:5][S:6][C:7]=2[CH:8]=1

Participants

5

Reactant 3

HCID 8000Boron trifluoride etherateHCID 516892Sodium BicarbonateHCID 13642516(2,2-Diethoxyethyl)(3-methoxyphenyl)sulfane

Product 1

HCID 136342376-Methoxy-1-benzothiopheneYield 66.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of 1-[(2,2-diethoxy)ethylthio]-3-methoxybenzene (13.0 g, 0.051 mol) in CH2Cl2 (100 ml) was added dropwise to a solution of BF3.Et2O (6.7 ml, 0.054 mol) in CH2Cl2 (1000 ml) at room temperature under a nitrogen atmosphere. The reaction mixture was stirred for 0.5 hours, treated with aqueous NaHCO3 solution, and stirred until both phases were clear. The CH2Cl2 layer was separated, and the aqueous layer was extracted with CH2Cl2. The combined organic extracts were dried over Na2SO4, filtered, and concentrated in vacuo to give 8.68 g of an approximately 10:1 mixture of 6- and 4-methoxybenzo[b]thiophene as a dark brown oil. Purification by vacuum distillation (bp=65°-7° C. at 0.3 mmHg) gave 5.58 g of pale yellow oil. Major isomer: 'H NMR, δ: (CDCl3): 3.85 (3H, s, --OCH3); 6.98 (1H, dd, J=4.5, H5); 7.23 (2H, s, H2, H3); 7.35 (1H, d, J=1.5, H7); 7.68 (1H, d, J=4.5, H4).

Workup

  1. stirringstirred until both phases
  2. customThe CH2Cl2 layer was separated
  3. extractionthe aqueous layer was extracted with CH2Cl2
  4. dry with materialThe combined organic extracts were dried over Na2SO4
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customto give
  8. customPurification
  9. distillationby vacuum distillation (bp=65°-7° C. at 0.3 mmHg)

Sources & evidence

ORD record
ord-fad25374393a49b7b912874756468ba5
Source dataset
uspto-grants-1988_11
Patent number
US04788192

Reaction notes

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