Thionyl Chloride → 1-(Benzo[b]thiophen-3-yl)-3-chloropropan-2-one

HRID 2375562Notes

Reaction equation

HRID 2375562 reaction equation
[Cl:1][CH2:2]C(=O)CC1SC=CC=1.[S:11]1[CH:15]=[C:14]([CH2:16][C:17]([OH:19])=O)[C:13]2[CH:20]=[CH:21][CH:22]=[CH:23][C:12]1=2.S(Cl)(Cl)=O>>[S:11]1[CH:15]=[C:14]([CH2:16][C:17](=[O:19])[CH2:2][Cl:1])[C:13]2[CH:20]=[CH:21][CH:22]=[CH:23][C:12]1=2

Participants

4

Reactant 3

HCID 24386Thionyl ChlorideHCID 70799Benzo[b]thiophene-3-acetic acidHCID 161002061-Chloro-3-(thiophen-2-yl)propan-2-one

Product 1

HCID 161001791-(Benzo[b]thiophen-3-yl)-3-chloropropan-2-oneYield 56%

Procedure

The procedure described above for the synthesis of 1-chloro-3-(thiophen-2-yl)propan-2-one was followed. To prepare the acid chloride, 2-(benzo[b]thiophen-3-yl)acetic acid (1.00 g, 5.20 mmol) was added to 6 mL thionyl chloride in a 25 mL round-bottomed flask. The mixture was stirred overnight at room temperature, and the thionyl chloride then removed in vacuo and the residue azeotroped twice with toluene. The acid chloride was then reacted with diazomethane and HCl. The crude product was purified by flash chromatography over silica gel (2-30% ethyl acetate in hexanes) to give pure material (0.661 g, 56% yield): 1H NMR (400 MHz, CDCl3) δ 4.12 (s, 2H) 4.14 (d, J=1.0 Hz, 2H) 7.36-7.44 (m, 3H) 7.67-7.71 (m, 1H) 7.87-7.90 (m, 1H).

Workup

  1. customthe thionyl chloride then removed in vacuo
  2. customthe residue azeotroped twice with toluene
  3. customThe acid chloride was then reacted with diazomethane and HCl
  4. customThe crude product was purified by flash chromatography over silica gel (2-30% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-2c40f2d070c64193a208144e751dfb42
Source dataset
uspto-grants-2008_12
Patent number
US07465798B2

Reaction notes

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