1,8-Diazabicyclo(5.4.0)undec-7-ene → Ethyl thieno[2,3-b]thiophene-2-carboxylate

HRID 225852Notes

Reaction equation

HRID 225852 reaction equation
[C:1]([CH2:6][S:7][C:8]1[S:9][CH:10]=[CH:11][C:12]=1[CH:13]=O)([O:3][CH2:4][CH3:5])=[O:2].C1CCN2C(=NCCC2)CC1>CO>[S:7]1[C:8]2[S:9][CH:10]=[CH:11][C:12]=2[CH:13]=[C:6]1[C:1]([O:3][CH2:4][CH3:5])=[O:2]

Participants

4

Reactant 2

HCID 811841,8-Diazabicyclo(5.4.0)undec-7-eneHCID 22593753HCID 22593753, compound

Product 1

HCID 22593799Ethyl thieno[2,3-b]thiophene-2-carboxylateYield 45%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a solution of 2-(carboethoxymethylthio)3-formylthiophene (from step c) in MeOH (200 mL) was added DBU (0.6 mL, 4.0 mmole) at 0° C. After 1 hr the mixture was warmed to RT and concentrated. The residue was taken up in EtOAc, washed with 10% HCl, H2O (3×), dried (MgSO4), and concentrated. Flash chromatography on silica gel (50% toluene/hexanes) gave the title compound (3.84 g, 45% over 4 steps) as an off-white solid: 1H NMR (400 MHz, CDCl3) δ 7.95 (s, 1 H), 7.40 (d, J=5.2 Hz, 1 H), 7.26 (d, J=5.2 Hz, 1 H), methyl ester 3.92 (s, 3 H), ethyl ester 4.38 (q, J=7.1 Hz, 2 H)) and 1.41 (t, J=2.4 Hz, 3 H).

Workup

  1. concentrationconcentrated
  2. washwashed with 10% HCl, H2O (3×)
  3. dry with materialdried (MgSO4)
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-fcebefdeddb742658c6fd70f34cf5642
Source dataset
uspto-grants-2009_07
Patent number
US07557125B2

Reaction notes

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