R. Wada, S. Kaga, Y. Kawai et al.
Tetrahedron 83 (2021) 131978
4.24. 2,20-Bis(4-butylphenyl)-5,50-bithiazole (14)
purified by flash column chromatography on silica gel (CH2Cl2) to
give the title compound (0.15 g, 82%) as a yellow solid. Rf ¼ 0.30
(hexane: CH2Cl2 ¼ 1 : 2). mp 221e223 ꢁC. IR(KBr) 3425, 2957, 2924,
2924, 2854, 1606, 1514, 1448, 1410, 1287, 960, 828, 681, 645, 574,
To a solution of 2-(4-butylphenyl)thiazole 13 (6.5 g, 30 mmol) in
DMF (90 mL) and DMSO (9 mL) were added Pd(OAc)2 (0.67 g,
3 mmol) and AgOAc (10 g, 60 mmol). The mixture was stirred at
80 ꢁC for 16 h, and then the mixture was filtered through a Celite
pad and filtrate was concentrated in vacuo. The residue was washed
with hexane and EtOAc to give the title compound (3.7 g, 56%) as a
yellow solid. Rf ¼ 0.04 (hexane: CH2Cl2 ¼ 1 : 2). IR(KBr) 2955, 2924,
2854, 2359, 1478, 1421, 1409, 973, 847, 749, 665, 628, 495 cmꢀ1. 1H
494 cmꢀ1
.
1H NMR (CDCl3)
d
7.92 (d, J ¼ 8.2 Hz, 4H, Ar), 7.29 (d,
J ¼ 8.2 Hz, 4H, Ar), 2.67 (t, J ¼ 7.3 Hz, 4H, Ar-CH2), 1.64 (quint,
J ¼ 7.3 Hz, 4H, AreCH2eCH2), 1.38 (sext, J ¼ 7.3 Hz, 4H, CH2eCH3),
0.95 (t, J ¼ 7.3 Hz, 6H, CH3). 13C NMR (CDCl3)
d 168.6, 156.5, 146.0,
131.1, 129.2, 126.4, 121.6 (Ar) 35.6, 33.4, 22.3, 13.9 (butyl). MS (EI) m/
z 462 (54, Mþ). HRMS (EI) Calcd for C26H26N2S3: 462.1258, found:
462.1256.
NMR (CDCl3)
d
7.90 (s, 2H, thiazole), 7.87 (d, J ¼ 8.2 Hz, 4H, Ar), 7.28
(d, J ¼ 8.2 Hz, 4H, Ar), 2.67 (t, J ¼ 7.3 Hz, 4H, Ar-CH2), 1.63 (quint,
J ¼ 7.3 Hz, 4H, Ar-CH2-CH2), 1.38 (sext, J ¼ 7.3 Hz, 4H, CH2eCH3),
0.95 (t, J ¼ 7.3 Hz, 6H, CH3). 13C NMR (CDCl3)
d 167.8, 145.9, 141.0,
4.28. 2,6-Bis(4-butylphenyl)thieno[2,3-d:5,4-d’]bisthiazole-4,4-
dioxide (12a)
130.8, 129.2, 128.1, 126.5 (Ar), 35.7, 33.5, 22.4, 14.0 (butyl). MS (EI)
m/z 432 (Mþ). HRMS (EI) Calcd for C26H28N2S2: 432.1694, found:
432.1681.
To a suspension of 2,6-bis(4-butylphenyl)thieno[2,3-d:5,4-d’]
bisthiazole-4-oxide(11a) (0.19 g, 0.4 mmol) in toluene and water (5/
2, 2 mL) was added NaOCl. 5H2O (66 mg, 0.4 mmol). The mixture
was stirred for 3 h and then extracted with CHCl3. The combined
organic layer was dried over MgSO4 and concentrated in vacuo. The
residue was purified by flash column chromatography on silica gel
(hexane: CH2Cl2 ¼ 1 : 1) to give the title compound (0.18 g, 93%) as a
yellow solid. Rf ¼ 0.75 (hexane: CH2Cl2 ¼ 1 : 2). mp 266e268 ꢁC. IR
(KBr) 3426, 2955, 2926, 2854, 2359, 1451, 1407, 1317, 1219, 1140,
4.25. 4,40-dibromo-2,20-bis(4-butylphenyl)-5,50-bithiazole (15)
To
a
solution of 2,20-bis(4-butylphenyl)-5,50-bithiazole 14
(0.93 g, 2 mmol) in CHCl3 (21 mL) and AcOH (7 mL) was added Br2
(0.2 mL, 4 mmol, 2 equiv). The mixture was stirred at room tem-
perature for 20 min and then quenched with sat. Na2S2O3aq and
extracted with CHCl3. The combined organic layer was concen-
trated in vacuo. These processes were repeated 3 times, and the
resulting residue was purified by flash column chromatography on
silica gel (CH2Cl2: hexane ¼ 2 : 1) to give 4,40-dibromo-2,20-bis(4-
butylphenyl)-5,50-bithiazole (1.1 g, 84%) as a yellow viscous oil.
Rf ¼ 0.68 (hexane: CH2Cl2 ¼ 1 : 1). IR(KBr) 3426, 3020, 2948, 2866,
1604, 1512, 1452, 1408, 1379, 1302, 1263, 987, 889, 839, 815, 780,
984, 829, 687, 603, 561 cmꢀ1. 1H NMR (CDCl3)
d
7.87 (d, J ¼ 8.2 Hz,
4H, Ar), 7.29 (d, J ¼ 8.2 Hz, 4H, Ar), 2.68 (t, J ¼ 7.7 Hz, 4H, Ar-CH2),
1.62 (quint, J ¼ 7.3 Hz, 4H, AreCH2eCH2), 1.38 (sext, J ¼ 7.3 Hz, 4H,
CH2eCH3), 0.96 (t, J ¼ 7.3 Hz, 6H, CH3). 13C NMR (CDCl3)
d 172.4,
153.8, 147.5, 129.6, 129.4, 126.8, 126.7 (Ar) 35.6, 33.3, 22.3, 13.9
(butyl). MS (EI) m/z 494 (41, Mþ). HRMS (EI) Calcd for
722, 643, 592, 531 cmꢀ1. 1H NMR (CDCl3)
d
7.88 (d, J ¼ 8.2 Hz, 4H,
C
26H26N2O2S3: 494.1156, found: 494.1144.
Ar), 7.28 (d, J ¼ 8.2 Hz, 4H, Ar), 2.67 (t, J ¼ 7.3 Hz, 4H, Ar-CH2), 1.64
(quint, J ¼ 7.2 Hz, 4H, AreCH2eCH2), 1.38 (sext, J ¼ 7.2 Hz, 4H,
4.29. 2,6-Bis(4-butylphenyl)selenopheno[2,3-d:5,4-d’]bisthiazole
(16)
CH2eCH3), 0.95 (t, J ¼ 7.2 Hz, 6H, CH3). 13C NMR (CDCl3)
d 168.9,
146.8, 129.8, 129.3, 128.2, 126.5, 121.7 (Ar), 35.7, 33.4, 22.4, 14.0
(butyl). MS (EI) m/z 592 (50, M(281Br)þ), 590 (100, M(79Brþ81Br)þ),
This compound was synthesized according to the general pro-
cedure, using 4,40-dibromo-2,20-bis(4-buyhylphenyl)-5,50-bithia-
zole (0.31 g, 0.5 mmol), n-BuLi (1.6 M in hexane, 0.7 mL, 1.1 mmol),
and neat SeOCl (0.113 mL, 0.6 mmol) in Et2O (10 mL). The title
compound was isolated as an orange solid (64 mg, 25%). Rf ¼ 0.40
79
588 (50, M(279Br)). HRMS (EI) Calcd for C26
found: 587.9907.
H Br2N2S2: 587.9904,
26
4.26. 2,6-Bis(4-butylphenyl)thieno[2,3-d:5,4-d’]bisthiazole-4-oxide
(11a)
(hexane: CH2Cl2 ¼ 4 : 1). 1H NMR (CDCl3)
d
7.90 (d, J ¼ 8.2 Hz, 4H,
Ar), 7.29 (d, J ¼ 8.2 Hz, 4H, Ar), 2.67 (t, J ¼ 7.3 Hz, 4H, Ar-CH2), 1.64
(quint, J ¼ 7.3 Hz, 4H, AreCH2eCH2), 1.38 (sext, J ¼ 7.3 Hz, 4H,
This compound was synthesized according to the general pro-
cedure, using 4,40-dibromo-2,20-bis(4-buyhylphenyl)-5,50-bithia-
zole (0.31 g, 0.5 mmol), n-BuLi (1.5 M in hexane, 0.7 mL, 1.1 mmol),
and neat thionyl chloride (0.036 mL, 0.5 mmol) in Et2O (10 mL). The
title compound was isolated as an orange solid (0.21 g, 86%).
Rf ¼ 0.25 (CH2Cl2). mp 191e193 ꢁC (dec.). IR (KBr) 3436, 2955, 2926,
2856, 1607, 1514, 1455, 1408, 1215, 981, 886, 829, 681, 568,
CH2eCH3), 0.95 (t, J ¼ 7.3 Hz, 6H, CH3). 13C NMR (CDCl3)
d 168.4,
156.0, 146.0, 131.1, 129.3, 126.5, 123.0 (Ar), 35.7, 33.4, 22.4, 14.0
(butyl). HRMS (EI) Calcd for C26H26N2S2Se: 510.0703, found:
510.0702.
507 cmꢀ1
.
1H NMR (CDCl3)
d
7.88 (d, J ¼ 8.2 Hz, 4H, Ar), 7.29 (d,
Declaration of competing interest
J ¼ 8.2 Hz, 4H, Ar), 2.67 (t, J ¼ 7.3 Hz, 4H, Ar-CH2), 1.64 (quint,
J ¼ 7.3 Hz, 4H, AreCH2eCH2), 1.38 (sext, J ¼ 7.3 Hz, 4H, CH2eCH3),
The authors declare that they have no known competing
financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
0.95 (t., J ¼ 7.3 Hz, 6H, CH3). 13C NMR (CDCl3)
d 171.3, 163.4, 147.0,
130.2, 129.7, 129.4, 126.7 (Ar), 35.7, 33.3, 22.4, 14.0 (butyl). MS (EI)
m/z 478 (6, Mþ), 462 (100, [MꢀO]þ). HRMS (EI) Calcd for
C
26H26N2OS3: 478.1207, found: 478.1198.
Acknowledgments
4.27. 2,6-Bis(4-butylphenyl)thieno[2,3-d:5,4-d’]bisthiazole (10a)
We are grateful for financial support from Grant-in-Aids for
Scientific Research on Innovative Area “Precisely Designed Cata-
lysts with Customized Scaffolding” (JSPS KAKENHI grant
18H04245) and for Scientific Research (B) (JSPS KAKENHI grant
20H02733). We also thank Tomohide Okada of Nippon Light Metal
Company, Ltd. for the generous donation of NaClO$5H2O.
To a suspension of 2,6-bis(4-butylphenyl)thieno[2,3-d:5,4-d’]
bisthiazole-4-oxide 11a (0.19 g, 0.4 mmol) in degassed THF, PBu3
(0.25 mL, 0.8 mmol) was added via syringe. After the mixture was
stirred for 19 h, the reaction was completed (monitored by TLC),
and the mixture was concentrated in vacuo. The residue was
8