Reaction #446331

Reaction equation

α-phenylcinnamic acid

α-mercaptophenylacetic acid

dibenzyl sulfide

sodium hydride

Methyl benzoylformate

→

3-Hydroxy-2,4,5-triphenylthiophene

Solvents

N,N-dimethylformamide

Conditions

Workup

1. 1
   Temperatureto cool
2. 2
   Temperaturethe mixture heated at 60° C. for 1 hour
3. 3
   Temperaturecooled
4. 4
   Otherseparated
5. 5
   Extractionthe aqueous layer re-extracted 1 time with ether
6. 6
   Washthe combined organic layer washed 2 times with water
7. 7
   Dryingdried over sodium sulfate
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated to a residue
10. 10
    OtherChromatography on silica gel (1 time flush with 10% ethyl acetate/hexane
11. 11
    Otheryielded 50 mg

Procedure

To an ice cooled, stirred solution of dibenzyl sulfide (2.14 g, 0.01 m) in dried N,N-dimethylformamide was added sodium hydride (0.88 g, 0.022 mmol of a 60% suspension in mineral oil). The mixture was gradually heated to 60° C. (bath temperature), kept 2 hours and allowed to cool. Methyl benzoylformate (1.42 ml, 0.01 mmol) was then added and the mixture heated at 60° C. for 1 hour, cooled, added to a stirred ice-dilute hydrochloric acid-ether mixture, separated, the aqueous layer re-extracted 1 time with ether, and the combined organic layer washed 2 times with water, dried over sodium sulfate, filtered and concentrated to a residue. Chromatography on silica gel (1 time flush with 10% ethyl acetate/hexane followed by a careful chromatography with a methylene chloride/hexane mixture) yielded 50 mg. of product compound as a pale yellow-white crystalline material. M.S.: M+ =328; NMR: consistent, identical to the nmr spectrum of material prepared from α-phenylcinnamic acid and α-mercaptophenylacetic acid via Michael addition and ring closure. ##STR28##

Source