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

HRID 1671634Notes

Reaction equation

HRID 1671634 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-84bc3fb38d564d5f8f6e969faae83354
Source dataset
uspto-grants-2011_08
Patent number
US07994333B2

Reaction notes

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