Synthesis of chiral imidazolium salts from a carbohydrate and their application in Pd-catalyzed
Suzuki-Miyaura reaction
Zhonggao Zhoua,b, Jiabin Qiua, Lifang Xiea, Fan Dua, Guohai Xua, Yongrong Xiea and Qidan Lingb,c*
1. General remarks.
2. General procedure for synthesis of chiral imidazolium salts
3. NMR (1H, 13C, COSY, HSQC and DEPT135), MS and IR spectra for the imidazolium salts.
4. GC-MS analysis.
5. General procedure for the Suzuki–Miyaura reaction.
6. Water content of the chiral imidazolium salts
7. NMR spectra (1H, or 1H and 13C, or 1H, 13C and HSQC) for the products of Suzuki-Miyaura
cross-coupling.
8. Acknowledgments.
9. References.
*
Correspondence to: yongrongxie@foxmail.com (Y-R. Xie), lingqd@fjnu.edu.cn (Q.-D Ling)
a
College of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou 341000, P. R. China
b
College of Materials Science and Engineering, Fujian Normal University, Fuzhou 350007, P. R. China
C
Fujian Key Laboratory of Polymer Materials, Fuzhou 350007, P. R. China
1
1. General remarks.
Chemicals and Materials
Starting materials D-glucose, perchloric acid, red phosphorus, liquid bromine, acetic anhydride,
imidazole, 1-bromobutane, 1,3-dibromopropane, α,α'-dichloro-p-xylene, α,α'-dichloro-o-xylene, aryl
halides, arylboronic acids and palladium salts were purchased from commercial suppliers (Aldrich or
Alfa Aesar) and used as received, anhydrous magnesium sulfate, sodium bicarbonate, sodium chloride,
chloroform, ether, methanol, dioxane, acetonitrile were provided by the Sinopharm Shemical Reagent
Co., Ltd, all the reagents were analytical grade. Solvents were dried with standard methods and freshly
distilled prior to use in the synthetic of imidazolium salts.
Instrumentation
NMR spectra were recorded on a Bruker Avance III 400 MHz ( 1H 400 MHz, 13C 100 MHz)
spectrometer. The NMR studies were carried out using CDCl 3 as solvent and the solvent signals were
used as references (δC = 77.0, δH = 7.26, residual CHCl3 in CDCl3). All of the experiments were carried
out on an Agilent 6890 GC with 5973 mass spectral detector, using an AT.SE-30 column of 50 m
length, 0.32 mm diameter and 0.5 μm film thicknesses. GC parameters for Suzuki-Miyaura reaction
were as follows: injector temperature 280 ◦C; detector temperature 280 ◦C; initial temperature 100 ◦C;
initial time 5 min; temperature ramp 1, 30 ◦C min−1; final temperature 200 ◦C; ramp 2, 20 ◦C min−1;
final temperature 250 ◦C; run time 30 min; inject 1.0 μL; helium as the GC carrier gas; pressure of the
system was 3.5 bar.
2. General procedure for synthesis of chiral imidazolium salts.
1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)imidazole
(2)
was
prepared
from
tetra-acetyl-α-D-glucopyranosyl bromide and imidazole according to the reported method.1
We prepare 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide first: 40 mL acetic anhydride is
mixed with 0.24 mL perchloric acid, and 10 g D-glucose was added three times within 0.5 hour in an
ice bath and control the temperature between 30 to 40 oC, then 3.0 g red phosphorus was added and
then added 18 g liquid bromine gradually and control the temperature below 20 oC, after that, 3.6 mL
2
water was added dropwise within 2 hours, the mixture was reacted another 2 hours. Then 30 mL
chloroform was added and the mixture was poured into 100 mL ice-water, the chloroform was washed
three times with ice-water (10 mL), then sodium bicarbonate solution and brings the pH to 6, dry with a
small amount of sodium bicarbonate then evaporated in vacuo and controled the water-bath
temperature below 50 oC, washed with dry ether, used directly in the next reaction.
2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (3.29 g), imidazole (1.2 g) were dissolved in dry
dioxane (10 mL) and reflux for 3 h. After cooled to room temperature the solid was formed, and
filtered off, washed three times with water, then dried, TLC showed two components to be present.
Recrystallistion from methane three times gave needles (45%),
1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)imidazole (2), m.p. 206-208o. 1H NMR (CDCl3): δ 5.33
(d, 1H, J1,2 = 6.54 Hz, H-1), 5.34 (t, 1H, J2,3 = 10.8 Hz, H-2), 5.32 (t, 1H, J3,4 = 8.6 Hz, H-3), 5.24 (t,
1H, J4,5 = 10.2 Hz, H-4), 3.93 (m, 1H, J5,6 = 4.94 Hz, H-5), 4.28 (dd, 1H, J5,6’ = 2.2 Hz, H-6), 4.16 (dd,
1H, J6,6’ = 12.65 Hz, H-6’), 2.09, 2.07, 2.02, and 1.88 (each 3H, s, OAc), 7.63-7.09 (H-imidazole); 13C
NMR (CDCl3): δ 83.66 (C-1), 70.62 (C-2), 72.87 (C-3), 67.78 (C-4), 74.87 (C-5), 61.65 (C-6),
116.78-136.65 (C-imidazole), 20.34-20.89 (OAc), 168.88-170.73 (C=O).
1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-3-butyl-imidazolium bromide (1a).
A 1.0 g (2.5 mmol) of compound 2, 25.0 mL of dry acetonitrile, and 1-bromobutane (0.4 g, 3.0
mmol) were added into a 50 mL flask, and the mixture was stirred under reflux for 12 h. The reaction
was monitored by TLC, after completion of the reaction, acetonitrile was removed by rotoevaporation
under vacuum and the residue was purified by chromatography (dichloromethane/methanol, 20/1 or
10/1), the solvent was removed under reduced pressure and then dried under vacuum.
3
Detected the reaction process used proton NMR spectrum in situ.
3. NMR (1H, 13C, COSY, HSQC and DEPT135), MS and IR spectra for the imidazolium salts.
1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)3-butyl-imidazolium bromide (1a).
4
5
Inten.(x1,000,000)
2.5
455.1
2.0
1.5
1.0
991.3
0.5
0.0 125.1 169.1 213.2239.2
100
150
200
250
289.3 331.1
300
350
413.1
400
450
497.3
500
559.3
550
6
600
641.3
650
697.3
700
750
796.4
800
854.4
850
905.4 945.3
900
950
m/z
1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyran
osyl)-3-(3-bromide-propyl)imidazolium bromide (1b).
7
Inten.(x100,000)
392.9
4.0
350.9
3.0
2.0
436.9
1.0
0.0 127.1
100
188.8
200
230.8
289.1
300
476.9
400
519.0
500
581.0 621.0
600
8
683.0 740.0 782.8 826.9 868.9 906.9 950.9 988.9
700
800
900
m/z
1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyrano
syl)-3-(2-chloromethyl-benzyl)imidazolium chloride (1c).
9
Inten.(x100,000)
4.0
495.1
453.1
3.0
2.0
537.0
411.1
1.0
0.0
100
139.1 181.1206.8
150
200
324.1
274.0
250
300
369.0
350
561.0
400
450
500
550
600
10
641.1
650
689.1 731.2 767.2 817.3 859.3 899.3 943.2 985.4
700
750
800
850
900
950 m/z
1-(2,3,4,6-tetra-O-acetyl-β-D-gluco
pyranosyl)-3-(4-chloromethyl-benzyl)imidazolium chloride (1d).
11
Inten.(x100,000)
494.7
5.0
536.9
452.9
2.5
212.9 247.0
96.8 138.8 180.9
289.0
0.0 65.0
50
100
150
200
250
300
410.9
370.0
350
400
450
500
4. GC-MS analysis.
12
563.2 605.0
550
600
649.3 691.0
650
700
747.1 789.0
750 m/z
All of the experiments were carried out on an agilent 6890 GC with 5973 mass spectral detector, using
an AT.SE-30 column of 50 m length, 0.32 mm diameter and 0.5 μm film thicknesses. GC parameters
for Suzuki-Miyaura reactions were as follows: injector temperature 280 ◦C; detector temperature 280
◦
C; initial temperature 100 ◦C; initial time 5 min; temperature ramp 1, 30 ◦C min−1; final temperature
200 ◦C; ramp 2, 20 ◦C min−1; final temperature 250 ◦C; run time 30 min; inject 1.0 μL; helium as the GC
carrier gas; pressure of the system was 3.5 bar.
5. General procedure for the Suzuki–Miyaura reaction.
The appropriate amounts of ligand, base and metal precursor were added to the required solvent (3.0
mL). The mixture was stirred for 30 min, then the aryl halide (0.5 mmol), aryl boronic acid (0.75
mmol) were added and the mixture was stirred under reflux and reacted in air atmosphere. The course
of the reaction was monitored by GC-MS analysis, and yields were calculated against the aryl halides.
On completion of the reaction, the solvent was removed under reduced pressure. The residue was
diluted with H2O (3.0 mL) and Et2O (3.0 mL), followed by extraction with Et2O (2×3.0 mL). The
organic fraction was dried over anhydrous MgSO4 then filtered and the solvent was evaporated under
reduced pressure. The crude product which was purified by column chromatography using 200-300
mesh silica gel and the purified products were characterized by NMR spectra, as well as literature
references of know compounds are given also.
4-Methyl-1,1'-biphenyl (Table 4, entries 1, 3 and 9); 2
1
H NMR (400 MHz, CDCl3): δ 7.58 (d, J = 7.6 Hz, 2H, Ar-H), 7.50 (d, J = 8.4 Hz, 2H, Ar-H), 7.44 (t,
J = 7.2 Hz, 2H, Ar-H), 7.33 (t, J = 6.8 Hz, 1H, Ar-H), 7.25 (t, J = 3.2 Hz, 2H, Ar-H), 2.41 (s, 3H, CH3),
MS (EI, m/z): 168 [M+].
Biphenyl (Table 4, entries 2 and 8);3
13
1
H NMR (400 MHz, CDCl3, δ): 7.35 (t, J = 5.6 Hz, 2 H, Ar-H), 7.43 (t, J = 8.0 Hz, 4 H, Ar-H), 7.59 (d,
J = 7.2 Hz, 4 H, Ar-H), MS (EI, m/z): 154 [M+].
4-Cyano-1,1'-biphenyl (Table 4, entry 4);4
1
H NMR (400 MHz, CDCl3): δ 7.53–7.64 (m, 4 H , Ar-H), 7.50 (d, 2 H, J = 7.8 Hz, Ar-H), 7.35–7.42
(m, 3 H, Ar-H), MS (EI, m/z): 179 [M+].
4-Methoxy-1,1'-biphenyl (Table 4, entry 5);5
1
H NMR (400 MHz, CDCl3): δ 7.54 (t, J = 8.0 Hz, 4H, Ar-H), 7.42 (t, J = 7.6 Hz, 2H, Ar-H), 7.31 (d, J
= 7.2 Hz, 1H, Ar-H), 6.98 (d, J = 8.8 Hz, 2H, Ar-H), 3.86 (s, 3H, OCH3), MS (EI, m/z): 184 [M+].
4-Acetyl-1,1'-biphenyl (Table 4, entry 6);2
1
H NMR (400 MHz, CDCl3): δ 8.19(d, J = 7.6 Hz, 1 H, Ar-H), 7.97 (d, J = 8.0 Hz, 2 H, Ar-H),
7.33~7.63 (m, 5 H, Ar-H), 7.18 (s, 1 H, Ar-H), 2.57 (s, 3 H, CH3), MS (EI, m/z): 196 [M+].
2-Methyl-1,1'-biphenyl (Table 4, entry 7);5
1
H NMR (400 MHz, CDCl3): δ 7.39-7.43 (m, 2H, Ar-H), 7.31-7.35 (m, 3H, Ar-H), 7.24-7.26 (m, 4H,
Ar-H), 2.25 (s, 3H, CH3), MS (EI, m/z): 168 [M+].
4-Trifluoromethyl-1,1'-biphenyl (Table 4, entry 10);6
1
H NMR (400 MHz, CDCl3): δ 7.33 (t, J = 7.2 Hz, 1 H, Ar-H), 7.40 (t, J = 7.4 Hz, 2 H, Ar-H), 7.54 (d,
J = 6.8 Hz, 2 H, Ar-H), 7.62 (s, 4 H, Ar-H), MS (EI, m/z): 222 [M+].
2-Methoxy-1,1'-biphenyl (Table 4, entry 11);5
1H NMR (400 MHz, CDCl3): δ 7.58–7.56 (m, 2H, Ar-H), 7.43–7.39 (m, 2H, Ar-H), 7.35–7.31(m, 2H,
Ar-H), 7.17–7.12 (m, 2H, Ar-H), 6.87 (dd, J = 8.4 and 2.4 Hz, 1H, Ar-H), 3.82 (s, 3H, CH3), MS (EI,
m/z): 184 [M+].
14
4,4'-Dimethyl-1,1'-biphenyl (Table 4, entry 12);7
1
H NMR (400 MHz, CDCl3): δ 7.47 (d, 4 H, J = 8.0 Hz, Ar-H); 7.23 (d, 4 H, J = 8.8 Hz, Ar-H), 2.39
(s, 6 H, CH3), MS (EI, m/z): 182 [M+].
4-Acetyl-3',5'-dimethyl-1,1'-biphenyl (Table 4, entry 13);8
1
H NMR (400 MHz, CDCl3): δ 8.03 (d, 2 H, J = 8.0 Hz, Ar-H); 7.68 (d, 2 H, J = 8.0 Hz, Ar-H), 7.26
(s, 2 H, Ar-H), 2.65 (s, 3 H, COCH3), 2.41 (s, 6 H, CH3), ppm. 13C NMR (100 MHz, CDCl3): δ 197.83,
146.08, 139.87, 138.52, 135.69, 129.90, 128.83, 127.22, 125.18, 26.67, 21.43, MS (EI, m/z): 224 [M+].
4-Acetyl-3',4',5'-trifluoro-1,1'-biphenyl (Table 4, entry 14);3
1
H NMR (400 MHz, CDCl3): δ 8.04 (d, 2 H, J = 8.0 Hz, Ar-H), 7.60 (d, 2 H, J = 8.0 Hz, Ar-H), 7.24
(m, 2 H, Ar-H), 2.65 (s, 3 H, CH3 ), ppm. 13C NMR (100 MHz, CDCl3, δ): 197.41, 151.52, 142.47,
139.79, 136.72, 135.97, 129.12, 127.03, 111.42, 111.26, 26.69, MS (EI, m/z): 250 [M+].
4-Acetyl-3',5'-difluoro-1,1'-biphenyl (Table 4, entry 15);9
1
H NMR (400 MHz, CDCl3): δ 8.03 (d, 2 H, J = 8.0 Hz, Ar-H), 7.62 (d, 2 H, J = 8.0 Hz, Ar-H), 7.11
(m, 2 H, Ar-H), 6.82 (m, 2 H, Ar-H), 2.64 (s, 3 H, CH3 ), ppm. 13C NMR (100 MHz, CDCl3, δ):
197.45, 164.56, 162.08, 143.37, 143.11, 136.76, 129.04, 127.16, 110.24, 110.05, 103.41, 26.65, MS
(EI, m/z): 232 [M+].
15
4-Acetyl-3',5'-ditrifluoromethyl-1,1'-biphenyl (Table 4, entry 16);10
1
H NMR (400 MHz, CDCl3): δ 8.10 (m, 2 H, J = 8.0 Hz, Ar-H), 8.06 (s, 2 H, Ar-H), 7.92 (s, 1 H,
Ar-H), 7.73(m, 2 H, J = 8.0 Hz, Ar-H), 2.68 (s, 3 H, CH3 ), ppm. 13C NMR (100 MHz, CDCl3): δ
197.38, 142.48, 142.04, 137.12, 132.38, 129.26, 127.50, 127.35, 124.57, 121.80, 119.14, 26.74, MS
(EI, m/z): 332 [M+].
4-Acetyl-4'-trifluoromethyl-1,1'-biphenyl (Table 4, entry 17);9
1
H NMR (400 MHz, CDCl3): δ 8.06 (d, 2 H, J = 8.0 Hz, Ar-H), 7.73 (s, d H, Ar-H), 7.68 (d, 2 H, J =
8.0 Hz, Ar-H), 2.65 (s, 3 H, CH3), ppm. 13C NMR (100 MHz, CDCl3): δ 197.50, 144.10, 143.37,
136.61, 130.20, 129.02, 127.58, 127.42, 125.87, 125.48, 122.77, 26.61, MS (EI, m/z): 264 [M+].
6. Water Content
Table 1S Water Content after the purification and dried procedure
Compound
1a
1b
1c
1d
Water content/ppm
180
175
155
165
7. NMR spectra (1H or 1H and 13C or 1H, 13C and HSQC) for the products of Suzuki-Miyaura
cross-coupling
16
17
18
19
20
21
22
23
24
8. Acknowledgments.
This work was financially supported by the National Natural Science Foundation of China (No.
21241005, 21363001 and 21061001), the Key Laboratory of Jiangxi University for Functional
Materials Chemistry, and Fujian Normal University.
25
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