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S. Hu et al. / Journal of Photochemistry and Photobiology A: Chemistry 270 (2013) 37–42
SCH3
O
C
O
O
HCl, HAc
SnCl2
I2, CuO
DMSO
CH3
C CH C C
SCH3
O
4
3
2
N
Br
N
SCH3
O
OH
33%HBr-HAc
(CH2O)n
6
SCH3
O
CH3CN, K2CO3
O
5
1
2.3. Synthesis
parameters for the non-hydrogen atoms. All H atoms were initially
located in a difference Fourier map. All H atoms were placed in
geometrically idealized positions and constrained to ride on their
˚
parent atoms, with C–H = 0.93 A and Uiso(H) = 1.2 Ueq(C).
2.3.1. Synthesis of 3-(bromomethyl)-4-(methylthio)-2,5-
diphenylfuran(5)
2.5. Analytical procedure
3-(Methylthio)-2,5-diphenylfuran (4) was prepared according
to literatures [25]. To a solution of 0.64 g of paraformaldehyde in
6.0 g of 33% hydrogen bromide-acetic acid reagent was added a
solution of 0.54 g (2 mmol) of compound 4 in 6 ml of glacial acetic
acid. The mixture was stirred for 2 h after which time the crystals
which formed were filtered off, and consequently recrystallized
from ethanol to afford pure compound 5 (0.51 g, 71.5%) as a pale
solid. M.p.: 160–161 ◦C. IR (KBr, cm−1): 1632, 1389, 1203, 768, 676.
1H NMR (CDCl3, 300 MHz): ␦ 8.03–8.01 (m, 2H), 7.54–7.86 (m, 2H),
7.35–7.52 (m, 6H), 4.75 (s, 2H) 2.48 (s, 3H); EI-MS: m/z 358.2, 359
[M+1], 360 [M+2], 361 [M+3].
The stock solutions of 1 (1.0 × 10−5 M) were prepared by dis-
solving 1 in DMF/water (98:2, v/v) containing BR buffer(10 mM,
pH = 7.0). The cationic stocks were all in H2O with a concentra-
tion of 3.0 × 10−3 M for UV–vis absorption and fluorescence spectra
analysis. For metal ion absorption and fluorescence titration exper-
iments, each time 3 mL solution of 1 filled in a quartz cell of 1 cm
optical path length, and we increased concentrations of metal ions
by stepwise addition of different equivalents using a micro-syringe.
After each addition of Fe3+ ion, the solution was stirred for 3 min.
The volume of cationic stock solution added was less than 100 L
with the purpose of keeping the total volume of testing solution
without obvious change. For all measurements of fluorescence
spectra of 1, the excitation was at 314 nm.
2.3.2. Synthesis of 8-((4-(methylthio)-2,5-diphenylfuran-3-yl)
methoxy)quinoline (1)
Compound 5 (0.358 g, 1.0 mmol) and quinolin-8-ol (6) (0.145 g,
1.0 mmol) was dissolved in CH3CN (20 mL) and K2CO3 (0.55 g,
4.0 mol) was added. The resultant mixture was refluxed for 3 h,
cooled to room temperature, diluted with 2 N HCl (50 mL) and
extracted with EtOAc (3 × 20 mL). The extracts were washed
with brine (2 × 20 mL) and dried over anh. MgSO4. After fil-
tration and rotary evaporation the residue was purified by
flash chromatography with petroleum as elust to give com-
pound 1(0.38 g, 65.2%) as a pale solid. Mp: 168–169 ◦C; IR (KBr,
cm−1): 3060, 2922, 1604, 1563, 1486, 1373, 1249, 1092, 970. 1H
NMR (300 MHz, CDCl3): ı = 8.19–8.23 (m, 2H), 8.12–8.15 (m,1H),
7.82–7.85 (m,2H), 7.302–7.53 (m,10H), 5.35 (s,2H), 2.36 (s,3H).
13C NMR (75 MHz, CDCl3): ı = 154.6, 152.8, 152.4, 1149.4, 140.4,
135.8, 130.4, 130.1, 129.5, 128.7, 128.5, 128.3, 126.7, 126.6, 126.1,
121.6, 120.7, 120.2, 116.9, 109.8, 61.9,19.6. EI-MS: m/z 424.3
[M+1].
3. Results and discussion
3.1. Synthesis and structural characteristics of 1
with compound 5 in CH3CN with K2CO3 as base under reflux. The
H
diffraction analysis.
The molecular view of 1 is shown in Fig. 1. A summary of crys-
tallographic data collection parameters and refinement parameters
for 1 are compiled in Table 1.
The structure of compound 1 is crystallized in Triclinic space
group P-1. The phenyl rings (C15–C20) and phenyl ring (C21–C26)
are bonded to the furan ring at the atoms of C12 and C13. They is
twisted away from the furan ring and form dihedral angles of 36.85◦
and 23.12◦ respectively, with the furan ring (O2–C12). The dihe-
dral angle between them is 22.13◦. The 8-hydroxyquinoline ring
is connected with the furan ring at the atoms of C11 by a bridged
methylene, the dihedral angle between them is 83.37◦. Because of
the presence of the electron-rich nitrogen, oxygen and sulfur atom
in the possible cavity, 1 has the potential to bind guests.
Regarding the crystal structure of 1, there is a intramolecular
C26–H26· · ·S1 hydrogen bond forming a pseudo six-membered.
The molecules are connected by weak C–H· · · interaction, which is
2.4. X-ray crystallography of compound 1
Suitable single crystals of 1 for X-ray structural analysis were
obtained by slow evaporation of a solution of 1 in CHCl3–CH3OH
(20:1, v/v) mixture at room temperature. The diffraction data was
collected with a Bruker SMART CCD diffractometer using a graphite
˚
monochromated MoK␣ radiation (ꢀ = 0.71073 A) at 296(2) K. The
structures were solved by direct methods with SHELXS-97 program
and refinements on F2 were performed with SHELXL-97 program
by full-matrix least-squares techniques with anisotropic thermal