Dang and Chen
TABLE 1. Photophysical Data of Compounds 1c-h in DCM
General Procedure for the Preparation of Compounds 1c-
1h. To a solution of 1b (0.5 mmol) in anhydrous THF (15 mL)
were added Pd(PPh3)4 (3 mol %) and a solution of K2CO3 solution
(2.5 M, 2 mL). The resulting solution was stirred for 10 min at
ambient temperature. To the resulting solution was added the
corresponding boronic acid reagent (1.5 mmol) under nitrogen, and
the reaction was monitored by TLC. After no further starting
material 1b was detected by TLC, H2O (20 mL) was added to the
residue, and the product was extracted with Et2O (3 × 20 mL).
The combined organic phase was washed with H2O (30 mL) and
a saturation solution of NaCl (30 mL), respectively, and dried over
MgSO4. After evaporation of the solvent, the crude product was
purified by flash column chromatography (PE-EtOAc). 1c. Yield:
82%. Mp ) 204-205 °C. 1H NMR δ: 7.16-7.10 (m, 10H), 6.96-
6.94 (m, 4H), 6.76-6.74 (d, J ) 8.8 Hz, 4H), 3.77 (s, 6H). 13C
NMR δ: 158.9, 138.8, 137.8, 136.9, 131.0, 130.5, 127.9, 127.0,
126.6, 113.9, 55.3. HRMS m/z: calcd for C30H24O2S 448.1497,
found 448.1495 (100%). Anal. Calcd for C30H24O2S: C, 80.40; H,
5.39. Found: C, 80.38; H, 5.33. 1d. Yield: 80%. Mp ) 174-
compd
λabsmax (nm)
ꢀ (×104)
λemmax (nm)
φf
1c
1d
1e
1f
1g
1h
320
310
350
300
370
330
1.87
1.75
1.77
1.75
3.01
1.98
418
0.029
446
417
464
418
0.021
0.020
0.081
0.098
procedure, and excellent yield. With 3,4-diaryl-2,5-dibro-
mothiophenes, a class of 2,4,5,6-tetraarylthiophenes has also
been prepared in good yields. These may provide a useful
synthetic route to the preparation of 3,4-diaryl-2,5-dibro-
mothiophenes and 2,3,4,5-tetraarylthiophenes.
Experimental Section
1
176 °C. H NMR δ: 8.14 (t, 2H), 8.09 (d, J ) 8.2 Hz, 2H), 7.51
General Procedure for the Preparation of Compounds 1b-
6b. To the solution of 1a-6a (1.0 mmol) in DCM (15 mL) was
added Br2 (2.5 mmol) in DCM (10 mL). The mixture was stirred
at room temperature until no further starting material was detected
by TLC. The solution was washed with water (50 mL), NaHCO3
(10%, 50 mL), and saturated NaCl solution (50 mL), respectively,
and extracted with DCM. The combined organic solution was dried
over MgSO4. After evaporation of the solvent, the target compounds
were obtained without further purification. 1b. Yield: 91%. Mp )
150-151 °C. 1H NMR δ: 7.25-7.23 (m, 6H), 7.07-7.05 (m, 4H).
13C NMR δ: 142.4, 134.6, 130.3, 128.1, 127.8, 109.7. HRMS
m/z: calcd for C16H10Br2S 393.8849, found 393.8853 (100%). Anal.
Calcd for C16H10Br2S: C, 48.79; H, 2.56. Found: C, 48.81; H,
2.51. 2b. Yield: 88%. Mp ) 129-130 °C. 1H NMR δ: 7.25 (d, J
) 8.5 Hz, 4H), 6.99 (d, J ) 8.4 Hz, 4H). 13C NMR δ: 140.9,
134.1, 132.7, 131.6, 128.6, 110.4. HRMS m/z: calcd for C16H8-
Br2Cl2S 461.8070, found 461.8071 (100%). Anal. Calcd for C16H8-
Br2Cl2S: C, 41.61; H, 1.75. Found: C, 41.58; H, 1.71. 3b. Yield:
(d, J ) 7.9 Hz, 2H), 7.39 (t, 2H), 7.22-7.15 (m, 6H), 6.98 (d, J )
7.6 Hz, 4H). 13C NMR δ: 148.4, 141.6, 136.8, 135.7, 135.2, 135.0,
130.6, 129.5, 128.5, 127.7, 124.0, 122.4. HRMS m/z: calcd for
C28H18N2O4S 478.0987, found 478.0985 (100%). Anal. Calcd for
C28H18N2O4S: C, 70.34; H, 3.79. Found: C, 70.38; H, 3.73. 1e.
Yield: 85%. Mp ) 155-156 °C. 1H NMR δ: 7.22-7.19 (m, 6H),
7.12-7.09 (m, 6H), 6.97 (d, J ) 3.6 Hz, 2H), 6.90 (dd, J1 ) 5.0
Hz, J2 ) 5.1 Hz, 2H). 13C NMR δ: 140.1, 136.2, 136.0, 131.3,
130.9, 128.2, 127.5, 127.0, 126.0, 125.7. HRMS m/z: calcd for
C24H16S3 400.0414, found 400.0405 (100%). Anal. Calcd for
C24H16S3: C, 72.06; H, 4.03. Found: C, 72.03; H, 3.98. 1f. Yield:
1
81%. Mp ) 203-205 °C. H NMR δ: 8.02 (d, J ) 7.8 Hz, 2H),
7.84-7.80 (m, 4H), 7.52 (d, J ) 7.0 Hz, 2H), 7.46-7.38 (m, 6H),
6.96 - 6.91 (m, 10H). 13C NMR δ: 140.7, 137.5, 136.5, 133.7,
132.9, 132.1, 130.5, 130.0, 128.6, 128.2, 127.6, 126.4, 126.4, 126.3,
126.0, 125.2. HRMS m/z: calcd for C36H24S 488.1599, found
488.1602 (100%). Anal. Calcd for C36H24S: C, 88.58; H, 4.95.
Found: C, 88.54; H, 4.93. 1g. Yield: 76%. Mp ) 269-271 °C.
1H NMR δ: 7.66-7.64 (m, 4H), 7.31-7.20 (m, 12H), 7.17-7.14
(m, 4H). 13C NMR δ: 141.5, 140.1, 139.6, 136.2, 135.6, 132.3,
130.9, 128.3, 127.8, 124.6, 123.6, 122.6, 122.1. HRMS m/z: calcd
for C32H20S3 500.0727, found 500.0733 (100%). Anal. Calcd for
C32H20S3: C, 76.86; H, 4.03. Found: C, 76.81; H, 3.97. 1h. Yield:
1
95%. Mp ) 103-104 °C. H NMR δ: 7.06 (d, J ) 7.9 Hz, 4H),
6.96 (d, J ) 8.0 Hz, 4H), 2.30 (s, 6H). 13C NMR δ: 142.3, 137.5,
131.7, 130.1, 128.8, 109.4, 21.4. HRMS m/z: calcd for C18H14-
Br2S 421.9162, found 421.9160 (100%). Anal. Calcd for C18H14-
Br2S: C, 51.24; H, 3.34. Found: C, 51.28; H, 3.29. 4b. Yield:
1
80%. Mp ) 132-134 °C. H NMR δ: 7.41 (d, J ) 8.5 Hz, 4H),
1
6.93 (d, J ) 8.4 Hz, 4H). 13C NMR δ: 140.8, 133.1, 131.9, 131.6,
122.4, 110.4. HRMS m/z: calcd for C16H8Br4S 551.7039, found
551.7040 (100%). Anal. Calcd for C16H8Br4S: C, 34.83; H, 1.46.
85%. Mp ) 250-251 °C. H NMR δ: 7.59 (d, J ) 7.4 Hz, 2H),
7.48 (d, J ) 8.3 Hz, 2H), 7.42 (t, 2H), 7.34-7.30 (m, 3H), 7.16-
7.12 (m, 3H), 7.05 (m, 2H). 13C NMR δ: 140.6, 139.9, 138.4, 136.7,
133.4, 131.0, 129.6, 128.9, 128.1, 127.5, 127.1, 127.0, 126.9. HRMS
m/z: calcd for C40H28S 540.1912, found 540.1908 (100%). Anal.
Calcd for C40H28S: C, 88.94; H, 5.22. Found: C, 88.91; H, 5.18.
1
Found: C, 34.88; H, 1.42. 5b. Yield: 89%. Mp ) 78-79 °C. H
NMR δ: 7.75-7.73 (m, 6H), 7.62 (d, J ) 8.6 Hz, 2H), 7.47-7.41
(m, 4H), 7.11 (dd, J1 ) 8.5 Hz, J2 ) 8.4 Hz, 2H). 13C NMR δ:
142.3, 133.0, 132.6, 132.0, 129.8, 128.3, 127.8, 126.5, 126.2, 110.2.
HRMS m/z: calcd for C24H14Br2S 493.9162, found 493.9164
(100%). Anal. Calcd for C24H14Br2S: C, 58.36; H, 2.86. Found:
C, 58.41; H, 2.82. 6b. Yield: 75%. Mp ) 216-218 °C. 1H NMR
δ: 7.55 (d, J ) 11.7 Hz, 4H), 7.35 (d, J ) 8.9 Hz, 2H), 7.01 (d,
J ) 8.9 Hz, 2H), 6.91 (d, J ) 11.7 Hz, 4H), 3.84 (s, 9H). 13C
NMR δ: 170.5, 160.9, 159.0, 134.2, 131.7, 127.8, 124.8, 121.4,
114.5, 114.3, 55.6, 55.4. Anal. Calcd for C25H21Br2NO3: C, 55.27;
H, 3.90. Found: C, 55.35; H, 3.85.
Acknowledgment. This work was supported by the National
Natural Science Foundation of China (No. 60337020).
Supporting Information Available: Synthetic procedures,
characterization data, and 1H NMR, 13C NMR, and HRMS spectra
of 1b-6b and 1c-h. This material is available free of charge via
JO071172I
6904 J. Org. Chem., Vol. 72, No. 18, 2007