4. Experimental section
4.1. General
1H (400.1 MHz), 13C (100.6 MHz) NMR spectra were recorded on
Bruker AVANCE 400 MHz spectrometer. Chemical shifts (d) are
given in ppm; the coupling constants (J) are given in Hertz. Theconcerted application of 1He1H 2D homonuclear experiments
NOESY and COSY as well as 1He13C 2D heteronuclear experiments
HMBC and HSQC were used for the distinction of the carbon and
proton resonances. The IR spectra were recorded with a Bruker
Vertex 70 FT-IR spectrometer and with a portable Varian 3100 diamond
ATR/FT-IR spectrometer. The GC/MS analyses were performed
with a Shimadzu GCeMS-QP5050A instrument (EI, 70 eV).
The silica gel used for column chromatographywas 230e400 Mesh.
All reagents were of reagent grade and were used as such or distilled
prior to use. All the solvents were dried according to standard
procedures and freshly distilled prior to use.
4.2. General procedure for synthesis of pushepull aroxyenones
2aee
An anhydrous KHCO3 (7 mmol) and corresponding phenol
(1 mmol) in 2 mL of dry acetone were placed into an Erlenmeyer
flask with a reflux condenser. Then the solution of ketone 1
(1 mmol) in 1 mL of dry acetone was added while stirred. The reaction
mixture was stirred under the room temperature for 20 h
and then diluted with 5 mL of diethyl ether. The precipitate was
filtered and washed with 2 mL of diethyl ether. The filtrate was
concentrated in vacuo, the residue was purified by column chromatography
(SiO2, CH2Cl2). The isomers ratio was defined for the
reaction mixture and varied slightly during purification. The following
aroxyenones 2aee were all prepared according to this
procedure.