1,5-Diazabicyclo(4.3.0)non-5-ene → Methyl thieno[2,3-b]thiophene-2-carboxylate

HRID 1382364Notes

Reaction equation

HRID 1382364 reaction equation
[CH:1]([C:3]1[CH:7]=[CH:6][S:5][C:4]=1[S:8][CH2:9][C:10]([O:12][CH3:13])=[O:11])=O.N12CCCC1=NCCC2>CO>[S:8]1[C:4]2[S:5][CH:6]=[CH:7][C:3]=2[CH:1]=[C:9]1[C:10]([O:12][CH3:13])=[O:11]

Participants

4

Reactant 2

HCID 763491,5-Diazabicyclo(4.3.0)non-5-eneHCID 11959090Methyl 2-(3-formyl-2-thienylthio)acetate

Product 1

HCID 12475296Methyl thieno[2,3-b]thiophene-2-carboxylateYield 80.6%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a solution of methyl (3-formylthiophene-2-ylthio)acetate (19.31 g, 91 g, 91 mmol) in methanol (150 mL) was added 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) (1 mL, 1 g, 8.05 mmol) and the stirred reaction flask was immediately immersed in an ice-water bath. Stirring was continued for 30 minutes and the mixture was filtered to give a tacky solid product which was washed with a little cold (-20° C.) methanol. The solvent was evaporated in vacuo from the mother liquor and the residue was partitioned between ether and aqueous sodium bicarbonate. The water layer was washed with ether twice, and the combined ether extracts were dried (MgSO4), filtered, and the solvent evaporated in vacuo to give an oil which solidified when triturated with a little cold (-20° C.) methanol. This was combined with the original solid product to give a total of 14.55 g of methyl thieno[2,3-b]thiophene-2-carboxylate, m.p. 101°-105° C. Recrystallization from methanol gave product with m.p. 106°-107° C. Anal. Calc'd for C8H6O2S2 : C, 48.47; H, 3.05. Found: C, 48.80; H, 3.32.

Workup

  1. customthe stirred reaction flask
  2. customwas immediately immersed in an ice-water bath
  3. filtrationthe mixture was filtered
  4. customto give a tacky solid product which
  5. washwas washed with a little cold (-20° C.) methanol
  6. customThe solvent was evaporated in vacuo from the mother liquor
  7. customthe residue was partitioned between ether and aqueous sodium bicarbonate
  8. washThe water layer was washed with ether twice
  9. dry with materialthe combined ether extracts were dried (MgSO4)
  10. filtrationfiltered
  11. customthe solvent evaporated in vacuo
  12. customto give an oil which
  13. customtriturated with a little cold (-20° C.) methanol

Sources & evidence

ORD record
ord-e34c7d7d86094544baf618fef1179102
Source dataset
uspto-grants-1989_02
Patent number
US04806562

Reaction notes

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