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acrylaldehyde (1 mmol) dissolved in DCM (15 mL) was stirred with
triphenylbenzyl phosphonium chloride (0.39 g, 1 mmol) for 5 min at room
temperature. To this was added 50% aqueous NaOH (7.5 mL) solution slowly and
the mixture was stirred further for 1 h at room temperature. The reaction
mixture was then poured onto ice-cold water (20 mL). A semi-solid obtained
was extracted with DCM (3 Â 25 mL), the organic layer was dried with
anhydrous sodium sulfate and the solvent was evaporated off. The crude
product obtained was purified by column chromatography on silica gel (60–
120 mesh) using ethyl acetate–hexane (1:19) mixture as the eluent to get 2a–g
in 78–90% yield as pale yellow crystalline solid.
24. General procedure for the synthesis of aryl-(2-(alkylthio)-5-phenylfuran-3-
yl)methanones from (E)-2-(bis(alkylthio)methylene)-1-aryl-4-phenylbut-3-en-1-
ones: A solution of (E)-2-(bis(alkylthio)methylene)-1-aryl-4-phenylbut-3-en-
1-ones (1 mmol) and NBS (264 mg, 1.5 mmol) in aqueous acetonitrile (5 mL)
was stirred at room temperature for 24 h. The reaction mixture was poured
onto ice-cold water and extracted with dichloromethane (2 Â 20 mL). The
organic layer was dried with anhydrous sodium sulfate, the solvent was
removed under vacuum and the crude product obtained was purified by
column chromatography on silica gel (60–120 mesh) using hexane as the
eluent to get 3a–g in 60–70% yield as white solid.
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23. General procedure for the synthesis of (E)-2-(bis(alkylthio)methylene)-1-aryl-
25. General procedure for the synthesis of (2-(ethylamino)-5-phenylfuran-3-
yl)(aryl)methanones from aryl-(2-(alkylthio)-5-phenylfuran-3-yl)methanones: To
a solution of aryl-(2-(alkylthio)-5-phenylfuran-3-yl)methanones (1 mmol) in
ethanol (5 mL) was added ethylamine (0.2 mL, 3 mmol) and the reaction
mixture was refluxed for 24 h. The reaction mixture was then poured onto
saturated sodium chloride solution (40 mL), neutralized with saturated
NaHCO3 and extracted with dichloromethane (3 Â 25 ml). The organic layer
was washed with water (2 Â 20 mL), dried over anhydrous Na2SO4 and purified
by column chromatography on silica gel (60–120 mesh) using hexane/ethyl
acetate (40:60) as the eluent to get 11a and 11e in 94–95% yield as pale yellow
solid.
4-phenylbut-3-en-1-ones:
The
appropriate
2-aroyl-3,3-bis(alkylthio)-