Acetic Acid → (benzo[b]thiophen-5-yl)-2,5-dimethyl-1H-pyrrole

HRID 2267294Notes

Reaction equation

HRID 2267294 reaction equation
[S:1]1[CH:5]=[CH:4][C:3]2[CH:6]=[C:7]([NH2:10])[CH:8]=[CH:9][C:2]1=2.[CH3:11][C:12](=O)[CH2:13][CH2:14][C:15](=O)[CH3:16].C(O)(=O)C>C1C=CC=CC=1.C(OCC)C>[S:1]1[CH:5]=[CH:4][C:3]2[CH:6]=[C:7]([N:10]3[C:15]([CH3:16])=[CH:14][CH:13]=[C:12]3[CH3:11])[CH:8]=[CH:9][C:2]1=2

Participants

6

Reactant 3

HCID 176Acetic AcidHCID 80352,5-HexanedioneHCID 288032Benzo(b)thiophen-5-amine

Product 1

HCID 57428820(benzo[b]thiophen-5-yl)-2,5-dimethyl-1H-pyrroleYield 97%

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 3283Diethyl EtherSolvent

Procedure

A stirred solution of benzo[b]thiophen-5-amine (2.48 g, 17.0 mmol), hexane-2,5-dione (1.95 mL, 17.0 mmol) and glacial acetic acid (0.2 mL) in benzene (35 mL) was heated to reflux under a Dean-Stark head. After 14 h the reaction was cooled to r.t., diluted with diethyl ether (40 mL), and successively washed with aqueous 2 N hydrochloric acid (30 mL), brine (30 mL), a saturated aqueous solution of sodium hydrogen carbonate (30 mL) and finally brine (30 mL). The organic layer was separated, dried over magnesium sulfate, filtered and the solvent evaporated in vacuo to yield 1-(benzo[b]thiophen-5-yl)-2,5-dimethyl-1H-pyrrole (3.67 g, 97%) as a light orange crystalline solid. 1H NMR δ (CDCl3, 400 MHz) 2.04 (s, 6 H), 5.93 (s, 2 H), 7.19 (dd, J=8, 2 Hz, 1 H), 7.37 (d, J=5 Hz, 1 H), 7.55 (d, J=5 Hz, 1 H), 7.66 (d, J=2 Hz, 1 H), 7.94 (d, J=9 Hz, 1 H).

Workup

  1. temperatureto reflux under a Dean-Stark head
  2. washsuccessively washed with aqueous 2 N hydrochloric acid (30 mL), brine (30 mL)
  3. customThe organic layer was separated
  4. dry with materialdried over magnesium sulfate
  5. filtrationfiltered
  6. customthe solvent evaporated in vacuo

Sources & evidence

ORD record
ord-b66ac67e2823491395836063477b0fd0
Source dataset
uspto-grants-2010_12
Patent number
US07858785B2

Reaction notes

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