N. Ziebart et al. / Tetrahedron xxx (2018) 1e6
5
(1H NMR (CDCl3):
(CDCl3): 14.1, 22.4, 34.2.). High-resolution mass spectra (HRMS)
were performed on LTQ Orbitrap XL apparatus. The synthesis of
thienylethene 5, chloro-thiophene 4, BTD-benzoic acid 23, iodo-
BODIPY 15 and iodo-phenyl-ethinyl 18 are described in detail in
the SI.
d
0.88 (t, J ¼ 7.0 Hz, 6H), 1.27 (m, 6H); 13C NMR
DMSO‑d6): d 14.0, 14.1, 61.7, 61.8, 81.7, 83.1, 108.6, 108.8,120.5, 122.8,
d
123.0, 128.4, 128.7, 129.2,129.9, 131.3, 131.5, 132.2, 133.7, 137.5, 164.6
(HMBC), 164.7 (HMBC), 166.9; HRMS (Esi neg): [M]- m/z Calcd for
C32H23F6O4S2 648.0869; Found 648.0855.
4.4. 4-(4-(2-(5-(4-((5,5-Difluoro-1,3,7,9-tetramethyl-5H-5l4,6l4-
dipyrrolo[1,2-c:20,10-f][1,3,2]diazaborinin-2-yl)ethynyl)phenyl)-2-
methoxy-4-methylthiophen-3-yl)-3,3,4,4,5,5-hexafluorocyclopent-
1-en-1-yl)-5-methoxy-3-methylthiophen-2-yl)benzoic acid (DTE-
BODIPY 2)
4.1. ((4-(4-(2-(5-Chloro-2-methoxy-4-methylthiophen-3-yl)-
3,3,4,4,5,5-hexafluorocyclopent-1-en-1-yl)-5-methoxy-3-
methylthiophen-2-yl)phenyl)ethynyl)trimethylsilane (6)
To a solution of 4 (230 mg, 952
m
mol) in abs THF (6 mL)
L, 991 mol) was added
mol)
A
solution of
PdCl2(PPh3)2 (3 mg, 3
(14 mL) and diisopropylamine (40 m
8
(57 mg, 151
mol) and CuI (2 mg, 10
L) was stirred at room tem-
m
mol), 15 (98 mg, 151
mmol),
at ꢁ78 ꢀC, n-BuLi (2.5 M in hexane, 390
m
m
m
mmol) in abs THF
dropwise and the solution stirred for 30 min. 5 (320 mg, 650
m
was added as a solid and the mixture warmed up to room tem-
perature in 60 min. The reaction was quenched with water,
extracted with Et2O, the organic layer dried (Na2SO4) and the sol-
vents removed in vacuo. Purification by flashchromatography (silica
perature for 22 h. The resulting mixture was poured into HCl (1 N)
and extracted with DCM, the organic layer was dried (Na2SO4) and
the solvents removed in vacuo. Purification by flashchromatog-
raphy (silica gel; cyclohexane/ETOAC: 1/1 þ 0.1% acetic acid) and
gel; pentane) gave 6 (252 mg, 396
m
mol, 64%) as a yellow solid. Rf
lyophilization gave DTE-BODIPY 2 (41 mg, 45.8 mmol, 31%) as a pink
0.3 (pentane); 1H NMR (500 MHz, CDCl3):
d
0.26 (s, 9H), 1.98 (s, 3H),
solid. Rf 0.5 (cyclohexane/EtOAc: 1/1 þ 0.1% acetic acid); 1H NMR
2.06 (s, 3H), 3.73 (s, 3H), 3.82 (s, 3H), 7.28e7.31 (m, J ¼ 8.4 Hz, 2H),
(500 MHz, CDCl3): d 2.13 (s, 3H), 2.16 (s, 3H), 2.27 (s, 3H), 2.35 (s,
7.44e7.48 (m, J ¼ 8.4 Hz, 2H); 13C NMR (125 MHz, CDCl3):
d
0.1, 12.8,
3H), 2.56 (s, 3H), 2.66 (s, 3H), 3.81 (s, 3H), 3.82 (s, 3H), 6.10 (s, 1H),
14.5, 61.5, 61.9, 95.4, 104.9, 108.8, 110.2, 112.2, 121.9, 124.1, 128.8,
131.1, 132.0, 132.3, 134.3, 160.8, 163.9; HRMS (APCI pos): [MþH]þ m/
z Calcd for C28H25ClF6O2S2Si 635.0731; Found 635.0735.
7.08 (s, 1H), 7.33e7.36 (m, J ¼ 8.2 Hz, 2H), 7.44e7.48 (m, J ¼ 8.0 Hz,
2H), 7.50e7.53 (m, J ¼ 8.2 Hz, 2H), 8.10e8.13 (m, J ¼ 8.0 Hz, 2H), 13
C
NMR (125 MHz, CDCl3):
d 10.8, 11.5, 13.6, 14.4, 14.6, 15.0, 61.5, 83.0,
95.5, 110.4, 110.8, 113.5, 120.2, 120.6, 122.4, 123.3, 124.1, 128.2, 128.8,
128.9, 130.7, 131.2, 131.6, 131.8, 132.3, 133.9, 134.8, 139.8, 140.9,
143.0, 157.7, 159.4, 163.8, 164.6, 171.1; HRMS (Esi neg): [M]- m/z
Calcd for C45H35BF8N2O4S2 898.1931; Found 898.1884.
4.2. Methyl 4-(4-(3,3,4,4,5,5-hexafluoro-2-(2-methoxy-4-methyl-
5-(4-((trimethylsilyl)ethynyl)phenyl)thiophen-3-yl)cyclopent-1-en-
1-yl)-5-methoxy-3-methylthiophen-2-yl)benzoate (7)
A solution of 6 (155 mg, 246
m
mol) in abs THF (5 mL) was cooled
4.5. ((4-(4-(3,3,4,4,5,5-Hexafluoro-2-(6-methoxy-2-methyl-3-
(phenylthio)phenyl)cyclopent-1-en-1-yl)-5-methoxy-3-
methylthiophen-2-yl)phenyl)ethynyl)trimethylsilane (10)
to ꢁ78 ꢀC, n-BuLi (2.5 M in hexane, 103
mL, 257 mmol) was added
dropwise and the solution stirred for 30 min. The mixture was
quenched with tributylborate (100
continued for 30 min. 20% aqueous Na2CO3 solution (5 mL),
Pd(PPh3)4 (28 mg, 25 mol) and 4-iodo benzoic acid methylester
(71 mg, 270
mL, 368 mmol) and stirring
To a solution of 9 (721 mg, 463 mmol) in abs THF (10 mL)
m
at ꢁ78 ꢀC, n-BuLi (2.5 M in hexane, 190
mL, 477 mmol) was added
m
mol) were added and the reaction mixture heated to
dropwise and the solution stirred for 30 min at ꢁ78 ꢀC. 5 (228 mg,
85 ꢀC for 4 h. The mixture was poured into H2O, extracted with
Et2O, the organic layer was dried (Na2SO4) and the solvents
removed in vacuo. Purification via flashchromatography (silica gel;
463 mmol) was added and the solution was warmed up to room
temperature for 60 min. The solution was poured into water,
extracted with Et2O and the organic layer dried (Na2SO4). Removing
the solvents in vacuo and purification by flashchromatography
pentane/DCM: 5/1 -> 3/2) yielded 7 (90 mg, 122
yellow solid. Rf 0.1 (pentane/DCM: 4/1); 1H NMR (500 MHz, CDCl3):
0.26 (s, 9H), 2.11 (s, 3H), 2.15 (s, 3H), 3.80 (s, 3H), 3.81 (s, 3H), 3.93
mmol, 50%) as a
(silica gel; pentane) yielded 10 (212 mg, 313
m
mol, 68%) as a yellow
d
solid. Rf 0.2 (pentane);1H NMR (500 MHz, CDCl3):
d
0.27 (s, 9H), 2.10
(s, 3H) 7.28e7.32 (m, J ¼ 8.0 Hz, 2H), 7.43e7.46 (m, J ¼ 8.1 Hz, 2H),
(s, 6H), 3.79 (2 s, 6H), 7.28e7.31 (m, 3H), 7.32e7.34 (m, J ¼ 8.4 Hz,
7.46e7.49 (m, J ¼ 8.0 Hz, 2H), 8.02e8.05 (m, J ¼ 8.1 Hz, 2H); 13C
2H), 7.35e7.39 (m, 4H), 7.48e7.52 (m, J ¼ 8.5 Hz, 2H); 13C NMR
NMR (125 MHz, CDCl3):
d
0.1, 14.3, 14.5, 52.2, 61.5, 95.4, 104.8, 110.4,
(125 MHz, CDCl3): d 0.1, 14.2, 14.4, 61.5, 95.3, 104.7, 110.4, 110.7,
110.7, 121.9, 123.5, 124.0, 128.5, 128.7 (2), 130.0, 131.3, 132.2, 132.4,
134.4, 138.9, 163.9, 164.4, 166.8; HRMS (APCI pos): [MþH]þ m/z
Calcd for C36H32F6O4S2Si 735.1490; Found 735.1490.
121.8, 123.9, 124.7, 127.3, 128.7, 128.8, 129.3, 130.6, 131.4, 132.3,
134.3, 134.5, 163.5; HRMS (APCI pos): [MþH]þ m/z Calcd for
C34H30F6O4S2Si 674.1433; Found 674.1428.
4.3. 4-(4-(2-(5-(4-Ethynylphenyl)-2-methoxy-4-methylthiophen-
3-yl)-3,3,4,4,5,5-hexafluorocyclopent-1-en-1-yl)-5-methoxy-3-
methylthiophen-2-yl)benzoic acid (8)
4.6. 2-(4-Ethynylphenyl)-4-(3,3,4,4,5,5-hexafluoro-2-(2-methoxy-
4-methyl-5-phenylthiophen-3-yl)cyclopent-1-en-1-yl)-5-methoxy-
3-methylthiophene (11)
To a solution of 7 (132 mg, 180
mmol) in THF (7 mL), aqueous 2 N
To a solution of 10 (129 mg, 190
mmol) dissolved in MeOH
NaOH (1.0 mL, 2.0 mmol) was added and the mixture was heated at
95 ꢀC for 12 h. After cooling down to room temperature, the sus-
pension was diluted with aqueous saturated NH4Cl solution,
extracted with Et2O and the organic layer dried (Na2SO4). Removing
the solvents in vacuo gave 8 (mixture of monomer and dimer;
(12 mL) stirred at room temperature aqueous NaOH (2 N, 600 mL)
was added, and the mixture heated to 50 ꢀC for 20 h. The resulting
mixture was cooled to room temperature, poured into HCl (3 N) and
extracted with Et2O. The organic layer was dried (Na2SO4) and the
solvents removed in vacuo to yield 11 (100 mg, 165
m
mol, 87%) as a
115 mg, 177
m
mol, 99%) as a colorless solid. Rf 0.6 (cyclohexane/
white solid. Rf 0.2 (pentane); 1H NMR (500 MHz, CDCl3):
d
2.11 (2 s,
EtOAc: 1/1 þ 0.1% acetic acid); 1H NMR (500 MHz, DMSO‑d6):
d
2.07
6H), 3.12 (s, 1H), 3.79 (s, 3H), 3.80 (s, 3H), 7.28e7.31 (m, 1H),
7.32e7.34 (m, 2H, J ¼ 8.5 Hz), 7.35e7.39 (m, 4H), 7.48e7.51 (m,
(s, 3H), 2.10 (s, 3H), 3.82 (s, 3H), 3.83 (s, 3H), 4.24 (s, 1H), 7.39e7.42
(m, J ¼ 8.3 Hz, 2H), 7.50e7.52 (m, J ¼ 8.3 Hz, 2H), 7.52e7.54 (m,
J ¼ 7.8 Hz, 2H), 7.95e7.98 (m, J ¼ 8.2 Hz, 2H); 13C NMR (125 MHz,
J ¼ 8.4 Hz); 13C NMR (125 MHz, CDCl3):
d
14.2, 14.4, 61.5 (2ꢂ), 78.1,
83.5, 110.3, 110.7, 120.8, 123.8, 124.7, 127.3, 128.7, 128.9, 129.3, 130.6,
Please cite this article in press as: Ziebart N, et al., Synthesis and characterization of non-symmetrical photoswitchable DTE(OMe) sensitizers,