Organometallics
Article
Ar-H, 2H), 6.88 (s, Ar-H, 2H), 6.83−6.77 (m, Ar-H, 8H), 6.70 (dd, J
= 9.3, 4.3 Hz, Ar-H, 2H), 6.60 (d, J = 7.0 Hz, Ar-H, 1H), 5.59 (s,
Ph2CH, 2H), 2.38 (s, CH3, 3H), 2.28 (s, CH3, 3H), 2.14 (s, CH3,
6H). 13C NMR (126 MHz, CDCl3): δ 143.1, 141.5, 141.4, 141.3,
141.2, 141.2, 137.7, 135.5, 133.9, 130.7, 130.1, 130.0, 129.7, 129.6,
129.4, 129.2, 129.0, 128.7, 128.2, 127.5, 127.1, 126.9, 126.5, 123.5,
122.9, 122.6, 122.1, 51.8, 21.9, 21.2, 18.1. HRMS (ESI+): 733.3564
(calcd for C55H45N2 [M − Cl]+ 733.3583).
arylation reactions were conducted under aerobic conditions. All
solvents were used as received. the Pd-PEPPSI complex (0.05−2.00
mol %), aryl bromide (1.00 mmol), heteroarene (3.00 mmol), base
(2.00 mmol), acid additive (0.30−4.00 mmol), and 3 mL of solvent
were placed in a parallel reactor. The reaction mixture was heated
with vigorous stirring at 130 °C for 12 h. After the mixture was cooled
to ambient temperature, 20 mL of water and 20 mL of dichloro-
methane were placed in the reactor, and the mixture was stirred for
another few minutes, followed by extraction three times with
dichloromethane (3 × 5 mL). The organic layers were then
combined, dried over anhydrous sodium sulfate, filtered, and
evaporated under reduced pressure to give the crude products. The
crude products were then purified by silica gel column chromatog-
raphy using petroleum ether/dichloromethane (15/1) as the eluent.
[2,6-(CHPh2)2-4-(OCH3)C6H2]{[NC(An)(An)CN]CH+Cl−}[(2,4,6-
(CH3)31C6H3)] (L2). L2 was obtained as an orange solid (0.67 g) in 86%
yield. H NMR (400 MHz, CDCl3): δ 11.76 (d, J = 16.5 Hz, 1H),
7.86 (d, J = 8.3 Hz, Ar-H, 1H), 7.79 (d, J = 8.3 Hz, Ar-H, 1H), 7.49−
7.44 (m, Ar-H, 1H), 7.29 (t, J = 6.5 Hz, Ar-H, 9H), 7.19 (d, J = 6.5
Hz, Ar-H, 2H), 7.13 (d, J = 6.9 Hz, Ar-H, 1H), 7.06 (s, Ar-H, 2H),
6.82 (dd, J = 12.8, 7.1 Hz, Ar-H, 8H), 6.70 (d, J = 6.4 Hz, Ar-H, 3H),
6.57 (s, Ar-H, 2H), 5.63 (s, CH, 2H), 3.59 (s, OCH3, 3H), 2.38 (s,
CH3, 3H), 2.12 (s, CH3, 6H). 13C NMR (101 MHz, CDCl3): δ 161.0,
143.4, 141.2, 141.1, 141.0, 137.8, 135.4, 133.9, 130.1, 129.6, 129.3,
129.2, 129.0, 128.8, 128.3, 127.5, 127.1, 127.0, 126.6, 124.8, 123.5,
123.0, 122.1, 115.5, 55.2, 51.9, 21.2, 18.1. HRMS (ESI+): 749.3510
(calcd for C55H45N2O [M − Cl]+ 749.3532).
1
The pure products obtained were characterized by H NMR and 13C
NMR spectroscopy, and the spectra can be found in the Supporting
Information. The isolated yields of products were obtained on the
basis of the amounts of (hetero)aryl bromides.
Procedure for the Synthesis of Compound 7. As described in
the general procedure for the direct arylation reactions, intermediate
5fi was obtained in 71% yield. Then 5fi (0.25 g, 1.00 mmol),
phenylboronic acid (1.46 g, 1.20 mmol), 0.5 mol % of Pd-PEPPSI-
IPrAn (0.004 g, 0.005 mmol) and K2CO3 (0.28 g, 2.00 mmol) were
dissolved in 3 mL of ethanol under an aerobic atmosphere. The
reaction mixture was stirred at 80 °C for 4 h. After completion of the
reaction, the resulting mixture was cooled to ambient temperature and
20 mL of water was added to it. Then the mixture was diluted with
dichloromethane (5 mL) and extracted three times with dichloro-
methane (3 × 5 mL). The organic layers were dried over anhydrous
magnesium sulfate and evaporated under reduced pressure. The
residue was purified by silica gel column chromatography to give the
title product 7 in 88% yield as a white solid.
General Procedure for the Synthesis of PEPPSI-Pd
Compounds C1 and C2. A mixture of PdCl2 (0.19 g, 1.10
mmol), the imidazolium salt (1.00 mmol), K2CO3 (1.38 g, 10.00
mmol), and 3-chloropyridine (5 mL) was stirred at 80 °C for 24 h
under a nitrogen atmosphere. After the mixture was cooled to room
temperature, 10 mL of dichloromethane was added to the resultant
solution. Then the solution was filtered through a pad of silica
covered with Celite and the solvents were removed under reduced
pressure. The resulting residue was redissolved and recrystallized from
dichloromethane/pentane to afford the corresponding products. A
single crystal of C1 suitable for X-ray diffraction studies was obtained
by layering its dichloromethane solution with pentane at ambient
temperature. Two solvent molecules (dichloromethane) were found
in the lattice.
2-Methyl-5-(1-methyl-4-phenyl-1H-pyrazol-5-yl)pyridine (7). 1H
NMR (400 MHz, CDCl3): δ 8.48 (d, J = 1.9 Hz, Ar-H, 1H), 7.73 (s,
Ar-H, 1H), 7.49 (dd, J = 8.0, 2.3 Hz, Ar-H, 1H), 7.24−7.20 (m, Ar-H,
3H), 7.20−7.17 (m, Ar-H, 1H), 7.15 (dd, J = 6.8, 1.6 Hz, Ar-H, 2H),
3.80 (s, CH3, 3H), 2.63 (s, CH3, 3H).13C NMR (101 MHz, CDCl3):
δ 159.0, 149.9, 137.9, 137.9, 136.6, 132.6, 128.6, 127.6, 126.4, 123.6,
123.3, 122.1, 37.4, 24.4.
Procedure for the Synthesis of Dantrolene. As described in
the general procedure for the direct arylation reactions, intermediate
3ca was obtained in almost quantitative yield. Then 1-amino-
imidazolidine-2,4-dione (2.53 g, 22 mmol) in 30 mL of 0.67 M HCl
was added to a solution of 3ca (4.04 g, 20 mmol) in 100 mL of DMF
at 0 °C. The resulting reaction mixture was stirred at room
temperature for 1 h. After completion of the reaction, 500 mL of
water was added to the reaction mixture, which furnished a great
amount of a reddish yellow precipitate. Then the pure dantrolene was
obtained by filtration, washed with water, and dried under vacuum
(3.17 g, 10.10 mmol, overall yield 51%). Its characterization data were
fully consistent with the reported data.20 1H NMR (400 MHz,
DMSO): δ 11.36 (s, NH, 1H), 8.32−8.28 (m, Ar-H, 2H), 8.01−7.97
(m, Ar-H, 2H), 7.76 (s, NCH, 1H), 7.44 (d, J = 3.6 Hz, Ar-H, 1H),
7.03 (d, J = 3.7 Hz, Ar-H, 1H), 4.36 (s, CH2, 2H).13C NMR (101
MHz, DMSO): δ 168.9, 153.4, 152.2, 151.1, 146.3, 135.2, 132.7,
124.6, 124.6, 115.7, 112.5, 49.0.
Procedure for the Synthesis of Mesopolymers. Under an
aerobic atmosphere, 3,4-ethylenedioxythiophene (0.142 g, 1 mmol),
2,7-dibromo-9,9-dioctylfluorene (0.548 g, 1 mmol), C1 (0.010 g, 1
mol %), and pivalic acid (1 mL, 30 mol %) were added to 3 mL of
mixed solvent (DMAc/THF 5/1). Then the reaction mixture was
stirred at 80 °C for 12 h. After it was cooled to room temperature, the
resulting mixture was poured into chilled acidic methanol (0.1 M
HCl), which furnished a great amount of precipitate. The crude
product was then obtained by filtration and washed with distilled
water, methanol, and hexane in sequence. The washed precipitate was
then recrystallized from MeOH. The desired mesopolymers were
obtained as brownish yellow solids in 56% yield (0.312 g), which has
an Mn value of 6.2 kDa and a dispersity of 1.64. 1H NMR (400 MHz,
[Pd(IPr*IMe)An(3-Cl-pyridinyl)Cl2] (C1). C1 was obtained as a
1
yellow solid (0.68 g) in 65% yield. H NMR (500 MHz, CDCl3): δ
8.91 (d, J = 2.3 Hz, Ar-H, 1H), 8.80 (dd, J = 5.5, 1.0 Hz, Ar-H, 1H),
7.77−7.63 (m, Ar-H, 1H), 7.51 (d, J = 8.2 Hz, Ar-H, 1H), 7.34 (d, J =
7.7 Hz, Ar-H, 4H), 7.23−7.18 (m, Ar-H, 6H), 7.18−7.14 (m, Ar-H,
4H), 7.11 (s, Ar-H, 2H), 6.83 (t, J = 7.5 Hz, Ar-H, 5H), 6.62−6.54
(m, Ar-H, 1H), 6.45 (s, Ar-H, 2H), 6.39 (t, J = 7.6 Hz, Ar-H, 4H),
6.25 (t, J = 7.4 Hz, Ar-H, 2H), 5.22 (d, J = 6.9 Hz, Ph2CH, 2H), 2.61
(s, CH3, 6H), 2.44 (s, CH3, 3H), 2.37 (s, CH3, 3H). 13C NMR (126
MHz, CDCl3): δ 155.2, 150.8, 149.8, 144.2, 143.7, 141.6, 140.5,
139.2, 139.0, 137.6, 137.3, 135.9, 134.8, 134.1, 132.1, 130.4, 130.2,
129.8, 129.7, 128.2, 127.9, 127.5, 127.3, 127.2, 126.2, 126.0, 125.8,
125.7, 125.6, 124.7, 124.4, 124.2, 122.1, 119.5, 51.2, 21.9, 21.3, 20.0.
HRMS (ESI+): 873.2230, 733.3565 (calcd for C55H44N2ClPd [M −
C5H4NCl − Cl − H]+ 873.2228, C55H45N2 [M − C5H4NCl − Cl2 −
Pd]+ 733.3583).
[Pd(IPrOMe*IMe)An(3-Cl-pyridinyl)Cl2] (C2). C2 was obtained as a
1
yellow solid (0.72 g) in 69% yield. H NMR (400 MHz, CDCl3): δ
8.92 (d, J = 2.1 Hz, Ar-H, 1H), 8.81 (dd, J = 5.5, 1.3 Hz, Ar-H, 1H),
7.69 (ddd, J = 8.2, 2.3, 1.3 Hz, Ar-H, 1H), 7.51 (d, J = 7.9 Hz, Ar-H,
1H), 7.37−7.34 (m, Ar-H, 4H), 7.24−7.19 (m, Ar-H, 6H), 7.17 (d, J
= 6.6 Hz, Ar-H, 4H), 6.87 (d, J = 1.1 Hz, Ar-H, 2H), 6.85 (s, Ar-H,
2H), 6.82 (s, Ar-H, 2H), 6.59 (dd, J = 8.3, 7.0 Hz, Ar-H, 1H), 6.48 (s,
Ar-H, 2H), 6.39 (t, J = 7.6 Hz, Ar-H, 4H), 6.25 (dd, J = 10.5, 4.2 Hz,
Ar-H, 2H), 5.28 (d, J = 6.8 Hz, Ar-H, 1H), 3.69 (s, OCH3, 3H), 2.61
(s, CH3, 6H), 2.44 (s, CH, 2H), 1.60 (s, CH3, 3H).13C NMR (101
MHz, CDCl3): δ 159.4, 155.5, 150.8, 149.8, 145.6, 143.8, 141.8,
140.2, 139.3, 137.6, 137.3, 136.0, 134.1, 132.1, 130.3, 130.3, 129.9,
129.7, 128.2, 127.8, 127.5, 127.4, 127.3, 126.2, 126.0, 126.0, 125.8,
125.7, 124.7, 124.5, 124.2, 122.2, 119.5, 115.2, 55.2, 51.4, 21.3, 20.0.
HRMS (ESI+): 889.2175, 749.3513 (calcd for C55H44N2ClOPd [M −
C5H4NCl − Cl − H]+ 889.2177, C55H45N2O [M − C5H4NCl − Cl2
− Pd]+ 749.3532).
General Procedure for Direct Arylation Reactions Promoted
by PEPPSI-Pd Complexes. Unless otherwise noted, the direct
H
Organometallics XXXX, XXX, XXX−XXX