Acetic Acid → Thieno(2,3-b)thiophene, 3,4-dibromo-

HRID 1640328Notes

Reaction equation

HRID 1640328 reaction equation
Br[C:2]1[S:11][C:5]2[S:6][C:7](Br)=[C:8]([Br:9])[C:4]=2[C:3]=1[Br:12].C(O)(=O)C>[Zn].O>[Br:9][C:8]1[C:4]2[C:3]([Br:12])=[CH:2][S:11][C:5]=2[S:6][CH:7]=1

Participants

5

Reactant 2

HCID 176Acetic AcidHCID 143033Thieno(2,3-b)thiophene, 2,3,4,5-tetrabromo-

Product 1

HCID 143030Thieno(2,3-b)thiophene, 3,4-dibromo-Yield 72.5%

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 962WaterSolvent

Procedure

A mixture of 2,3,4,5-tetrabromothieno[2,3-b]thiophene (0.83 g, 1.8 mmol), zinc dust (0.29 g, 4.4 mmol), and acetic acid (30 ml) is refluxed for 2 h. The reaction mixture is poured into water, extracted with DCM, washed with aqueous saturated sodium carbonate solution, dried (Na2SO4), and concentrated under reduced pressure. The product is purified by recrystallisation from hot methanol to obtain white fibrous crystals (389 mg, 72%). M/Z (298, t, M+). Found C, 24.5; H, 0.8. Calc. for C6H2Br2S2C, 24.2; H, 0.7. 1H NMR (300 MHz, CDCl3) δ 7.32 (s, 2H). 13C NMR (300 MHz, CDCl3) δ 139.35, 137.42, 126.44, 102.96.

Workup

  1. temperatureis refluxed for 2 h
  2. extractionextracted with DCM
  3. washwashed with aqueous saturated sodium carbonate solution
  4. dry with materialdried (Na2SO4)
  5. concentrationconcentrated under reduced pressure
  6. customThe product is purified by recrystallisation from hot methanol

Sources & evidence

ORD record
ord-727fb6da539442389e9bf6d7b5bf3943
Source dataset
uspto-grants-2012_02
Patent number
US08114316B2

Reaction notes

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