D
K. H. Park et al.
Paper
Synthesis
2,5-Di(hex-1-ynyl)-3,4-diiodothiophene (3b); Typical Procedure
2,6-Dibutyldithieno[3,2-b:2′,3′-d]thiophene (4b); Typical Proce-
dure
Tetraiodothiophene (4 g, 6.80 mmol) was added to a solution of CuI
(0.0626 g, 0.329 mmol), trans-dichlorobis(triphenylphosphine)palla-
dium (0.231 g, 0.329 mmol), 1-hexyne (1.23 g, 14.96 mmol), and di-
isopropylamine (250 mL). The mixture was stirred at r.t. for 21 h, then
heated to reflux for 1 h. After cooling to r.t., the mixture was filtered
and the solid was washed with CH2Cl2 (3 × 25 mL) and the washings
were combined. The solution was dried over anhydrous MgSO4, fil-
tered, and the solvent was removed to give a residue that was purified
by chromatography on silica gel.
A
mixture
of
2,5-di(hex-1-ynyl)-3,4-diiodothiophene
(1 g,
2.02 mmol), Na2S·9H2O (2.90 g, 12.12 mmol), CuI (0.0768 g,
0.403 mmol), and TMEDA (0.094 g, 0.806 mmol) in DMF (30 mL) was
stirred at 80 °C for 24 h under a nitrogen atmosphere. Upon comple-
tion, the reaction mixture was extracted with Et2O (20 mL per time)
until no product was observed in the extract, as monitored by TLC.
The combined extract was washed with brine and dried with anhy-
drous MgSO4. After filtration, the solvent was removed and the resi-
due was purified by chromatography on silica gel.
3,4-Diiodo-2,5-bis[2-(trimethylsilyl)ethynyl]thiophene (3a)
Yield: 2.85 g (79.2%); ivory solid; mp 85–89 °C.
Dithieno[3,2-b:2′,3′-d]thiophene (4a)
Yield: 0.220 g (59.1%); pale-brown solid; mp 63–68 °C.
1H NMR (400 MHz, CDCl3): δ = 7.36 (d, J = 4.8 Hz, 2 H), 7.29 (d, J =
4.8 Hz, 2 H).
1H NMR (400 MHz, CDCl3): δ = 0.28 (s, 18 H).
13C NMR (100 MHz, CDCl3): δ = 126.82, 105.05, 101.44, 98.23, 0.00.
HRMS (ESI): m/z [M + H]+ calcd for C16H18I2S: 528.8829; found:
528.8830.
13C NMR (100 MHz, CDCl3): δ = 141.54, 130.82, 125.78, 120.74.
UV/Vis (CHCl3): λmax = 292, 305 nm.
HRMS (ESI): m/z [M + H]+ calcd for C8H4S3: 196.9548; found:
2,5-Di(hex-1-ynyl)-3,4-diiodothiophene (3b)
196.9556.
Yield: 2.54 g (75.1%); brown solid; mp 50–54 °C.
1H NMR (400 MHz, CDCl3): δ = 2.48 (t, J = 7.2 Hz, 4 H), 1.59–1.66 (m,
4 H), 1.44–1.53 (m, 4 H), 0.90 (t, J = 6.8 Hz, 6 H).
2,6-Dibutyldithieno[3,2-b:2′,3′-d]thiophene (4b)
Yield: 0.369 g (59.1%); brown oil.
13C NMR (100 MHz, CDCl3): δ = 126.43, 99.42, 98.69, 77.42, 30.32,
21.95, 19.50, 13.56.
HRMS (ESI): m/z [M + H]+ calcd for C14H18I2SSi2: 496.9291; found:
496.9297.
1H NMR (400 MHz, CDCl3): δ = 6.94 (s, 2 H), 2.88 (t, J = 8 Hz, 4 H),
1.66–1.74 (m, 4 H), 1.37–1.46 (m, 4 H), 0.94 (t, J = 7.2 Hz, 6 H).
13C NMR (100 MHz, CDCl3): δ = 146.3, 139.17, 129.03, 117.42, 33.68,
30.79, 22.09, 13.80.
2,5-Bis[2-(4-butylphenyl)ethynyl]-3,4-diiodothiophene (3c)
UV/Vis (CHCl3): λmax = 292 nm.
HRMS (ESI): m/z [M + H]+ calcd for C16H20S3: 309.0799; found:
Yield: 4.07 g (92.2%); yellow solid; mp 95–98 °C.
1H NMR (400 MHz, CDCl3): δ = 7.48 (d, J = 8.4 Hz, 4 H), 7.19 (d, J =
8.4 Hz, 4 H), 2.63 (t, J = 7.8 Hz, 4 H), 1.57–1.64 (m, 4 H), 1.31–1.40 (m,
4 H), 0.93 (t, J = 7.2 Hz, 6 H).
309.0800.
2,6-Di(4-butylphenyl)dithieno[3,2-b:2′,3′-d]thiophene (4c)
13C NMR (100 MHz, CDCl3): δ = 144.53, 131.61, 128.59, 126.68,
Yield: 0.372 g (52.4%); yellow solid; mp 185–190 °C.
119.13, 100.18, 98.15, 83.32, 35.67, 33.31, 22.29, 13.91.
HRMS (ESI): m/z [M + H]+ calcd for C28H28I2S: 648.9917; found:
648.9923.
1H NMR (400 MHz, CDCl3): δ = 7.54 (d, J = 8.4 Hz, 4 H), 7.45 (s, 2 H),
7.21 (d, J = 8.4 Hz, 4 H), 2.63 (t, J = 7.2 Hz, 4 H), 1.58–1.66 (m, 4 H),
1.33–1.42 (m, 4 H), 0.94 (t, J = 7.2 Hz, 6 H).
13C NMR (100 MHz, CDCl3): δ = 117.24, 145.19, 142.90, 141.47,
131.99, 129.10, 125.60, 116.00, 35.36, 33.52, 22.34, 14.19.
3,4-Diiodo-2,5-bis[2-(4-pentylphenyl)ethynyl]thiophene (3d)
Yield: 4.31 g (93.6%); yellow solid; mp 89–92 °C.
UV/Vis (CHCl3): λmax = 373 nm.
1H NMR (400 MHz, CDCl3): δ = 7.48 (d, J = 8.4 Hz, 4 H), 7.19 (d, J =
8 Hz, 4 H), 2.63 (t, J = 7.6 H, 4 H), 1.58–1.66 (m, 4 H), 1.30–1.35 (m,
8 H), 0.90 (t, J = 7.6 Hz, 6 H).
HRMS (ESI): m/z [M + H]+ calcd for C28H28S3: 461.1425; found:
461.1141.
13C NMR (100 MHz, CDCl3): δ = 144.95, 131.98, 128.97, 127.06,
2,6-Di(4-pentylphenyl)dithieno[3,2-b:2′,3′-d]thiophene (4d)
119.48, 100.52, 98.51, 83.67, 36.41, 31.76, 31.22, 22.85, 14.36.
HRMS (ESI): m/z [M + H]+ calcd for C30H30I2S: 677.0230; found:
677.0227.
Yield: 0.348 g (48.2%); orange solid; mp 192–198 °C.
1H NMR (400 MHz, CDCl3): δ = 7.55 (d, J = 7.6 Hz, 4 H), 7.47 (s, 2 H),
7.22 (d, J = 8.4 Hz, 4 H), 2.63 (t, J = 8 Hz, 4 H), 1.61–1.68 (m, 4 H),
1.32–1.38 (m, 8 H), 0.91 (t, J = 6.4 Hz, 6 H).
2,5-Bis[2-(4-butylphenyl)ethynyl]-3,4-diiodothiophene (3e)
13C NMR (100 MHz, CDCl3): δ = 145.18, 142.93, 141.45, 131.96,
129.94, 129.06, 125.57, 115.97, 65.93, 41.00, 29.68, 15.25, 1.00.
Yield: 3.80 g (86.1%); ivory solid; mp 135–138 °C.
1H NMR (400 MHz, CDCl3): δ = 7.51 (d, J = 8.4 Hz, 4 H), 7.40 (d, J =
8.8 Hz, 4 H), 1.34 (s, 18 H).
13C NMR (100 MHz, CDCl3): δ = 152.68, 131.47, 126.70, 125.50,
UV/Vis (CHCl3): λmax = 373 nm.
HRMS (ESI): m/z [M + H]+ calcd for C30H32S3: 489.1738; found:
489.1728.
118.98, 100.24, 98.08, 83.32, 34.91, 31.13.
HRMS (ESI): m/z [M + H]+ calcd for C28H28I2S: 648.9917; found:
2,6-Di(4-tert-butylphenyl)dithieno[3,2-b:2′,3′-d]thiophene (4e)
648.9917.
Yield: 0.386 g (54.3%); yellow solid; mp 240–244 °C.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–E