Reaction #1929043

Reaction equation

Dibenzothiophene oxide

4-methoxybenzoic acid

Sodium iodide

Eaton's Reagent

→

title compound

Yield 55.0%

5-(5-carboxy-2-methoxyphenyl)-5H-dibenzo[b,d]thiophenium iodide

Yield 55.0%

Solvents

water

water

dichloromethane

Conditions

Workup

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   TemperatureThe reaction mixture was cooled back to 0° C.
3. 3
   Otherquenched with the slow addition of water (800 mL)
4. 4
   FiltrationThe precipitate was filtered off
5. 5
   Otherthe layers separated
6. 6
   ExtractionThe aqueous layer was extracted with ethyl acetate (2×500 mL)
7. 7
   Washthe combined organic layers were washed with water (500 mL)
8. 8
   OtherThe crude oil was recrystallized from acetone

Procedure

Dibenzothiophene oxide (57 g, 285 mmol) and 4-methoxybenzoic acid (47.7 g, 314 mmol, 1.1 eq) were suspended in dichloromethane (400 mL) and cooled to 0° C. where Eaton's Reagent (285 mL) was added dropwise. The solution was taken off ice and stirred overnight at r.t. The reaction mixture was cooled back to 0° C. and quenched with the slow addition of water (800 mL), followed by ethyl acetate (500 mL). The precipitate was filtered off and the layers separated. The aqueous layer was extracted with ethyl acetate (2×500 mL) and the combined organic layers were washed with water (500 mL). Sodium iodide (341.6 g, 2.28 mol, 4 eq) in water (500 mL) was slowly poured onto the combined aqueous layers. Additional water was slowly added until precipitation of a viscous oil stopped. The crude oil was recrystallized from acetone afford the title compound (72.0 g, 55%) as a white solid. 1H NMR (300 MHz, (d-DMSO) δ: 12.0-13.0 (brs, 1H), 8.54 (d, J=7.8 Hz, 2H), 8.35 (d, J=8.1 Hz, 2H), 8.21 (dd, J=8.7, 2.1 Hz, 1H), 7.99 (t, J=7.8 Hz, 2H), 7.79 (t, J=7.8 Hz, 2H), 7.51 (d, J=8.7 Hz, 1H), 7.44 (d, J=2.1 Hz, 1H), 4.08 (s, 3H).

Source