JOURNAL OF CHEMICAL RESEARCH 2009 743
O
+
N
N
I(OH)OTs
R2
R1
BF4
O
R2
+
R1
N
BF4
N
I
m-CPBA
PTSA
OTs
Scheme 3
3113, 1717, 1635, 1599, 1577, 1563, 1408 (S = O), 1164 (S = O),
Table 3 The yields of compound 3 for the recycling in
a-tosyloxylation of acetophenone
818 cm-1. MS: m/z 298.9 (100), [M+ -BF4 -OH -OTs], (HP5890-
‾
GCQ); 298 (M+-BF4 - OH- TsOH), 218 (CH3-C6H4-I+), 217 (I-C6H4-
‾
Time
Yield/%
CH2+), 91 (100) (C6H5-CH2+), 82 (1-methylimidazole)(Agilent
5975I). Anal. Calcd for C18H20BF4IN2O4S: C 37.63, H 3.51, N 4.88.
Found: C 37.50, H 3.57, N 4.83%.
1
2
3
4
5
92.0
91.9
91.8
91.7
91.7
a-Tosyloxyacetone: M.p. 35°С; lit34 37°С. 1H NMR (DMSO-d6):
d (ppm) 2.07 (s, 3H, carbonyl-CH3), 2.43 (s, 3H, Ar-CH3), 4.84 (s,
2H, CH2), 7.50 (d, J = 8.0 Hz, 2H, ArH), 7.83 (d, J = 8.0 Hz, 2H,
ArH). 13C NMR (DMSO-d6): d (ppm) 21.1, 26.0, 72.5, 127.7, 130.2,
132.3, 145.2, 200.0.
Diethyl a-(tosyloxy)malonate: Oil.35 1H NMR (CDCl3): d (ppm)
1.24 (t, J = 7.5 Hz, 6H, -2CH3), 2.46 (s, 3H, Ar-CH3), 4.21 (q,
J = 7.5 Hz, 4H, CH2), 5.29 (s, 1H, CH), 7.36 (d, J = 8.0 Hz, 2H,
ArH), 7.84 (d, J = 8.0 Hz, 2H, ArH).13C NMR (CDCl3): d (ppm)
13.8, 21.7, 62.9, 74.7, 128.3, 129.9, 132.5, 145.7, 163.2.
Method 3: 1 (0.78 g, 2.01 mmol) and PTSA monohydrate (0.35 g,
1.83 mmol) were dissolved in acetonitrile (20 mL), and then m-CPBA
(0.32 g, 1.83 mmol) was added and the mixture was stirred for
30 min at 30°С under a nitrogen atmosphere. The solvent was
removed in vacuo to afford a semi-solid material, which was then
dissolved in water (10 mL). Insoluble materials were removed by
filtration, and the filtrate was concentrated in vacuo, the residue was
further dried under high vacuum (<5 mmHg) at 50°С for 12 h to
afford 3 (1.04 g. 99.1%) as a viscous liquid.
a-Tosyloxyacetophenone: M.p. 74.3–74.7°С; lit21 74–76°С. 1H
NMR (CDCl3): d (ppm) 2.45 (s, 3H, CH3), 5.28 (s, 2H, CH2), 7. 35 (d,
J = 7.5 Hz, 2H, ArH), 7.48 (t, J = 7.5 Hz, 2H, ArH), 7.62 (t, J = 7.5 Hz,
1H, ArH), 7.85 (d, J = 7.5 Hz, 2H, ArH), 7.86 (d, J = 7.5 Hz, 2H,
ArH). 13C NMR (CDCl3): d (ppm) 21.7, 69.9, 128.0, 128.2, 128.9,
129.9, 132.7, 133.8, 134.2, 145.3, 190.3.
General method for the synthesis of a-tosyloxylation of ketones
Method 1: Ketones (1 mmol or 2 mmol) were added to a solution
of ion-supported HTIB 3 (1.2 mmol or 2.4 mmol) in acetonitrile
(6 mL), the mixture was stirred in a microwave reactor (600 W).
The reaction times and temperatures are specified in Table 1. The
product was purified as follows: the solvent was evaporated under
reduced pressure to give a solid residue, which was washed with
ether (10 mL × 2) to afford the expected ion-supported iodobenzene 1
as a white solid, and the washings were combined, and concentrated
under reduced pressure to give the residue, which was further purified
by preparative TLC on silica gel (benzene:ethyl acetate: 10:1) to
give a-tosyloxyketones.
Method 2: Ketone (1 mmol or 2 mmol) was added to the solution of
ion-supported HTIB 3 (1.2 mmol or 2.4 mmol) in [emim]BF4 (10 mL)
and the mixture was stirred in a microwave reactor (600 W). The
reaction times are specified in Table 2. The product was extracted
by ether, the expected ion-supported iodobenzene 1 was dissolved
in the [emim]BF4, the ether solution was concentrated under
reduced pressure to give the residue, which was further purified by
preparative TLC on silica gel (benzene:ethyl acetate = 10:1) to give
a-tosyloxyketones.
a-Tosyloxy-p-bromoacetophenone: M.p. 131.5–132.4°С; lit21
131–133°С.1H NMR (CDCl3): d (ppm) 2.45 (s, 3H, CH3), 5.22
(s, 2H, CH2), 7.35 (d, J = 10.0 Hz, 2H, ArH), 7.44 (d, J = 8.5 Hz,
2H, ArH), 7.78 (d, J = 8.5 Hz, 2H, ArH),7.84 (d, J = 10.0 Hz, 2H,
ArH).13C NMR (CDCl3): d (ppm) 21.7, 69.8, 128.1, 129.3, 129.9,
131.4, 131.9, 132.3, 132.6, 145.3, 189.9.
a-Tosyloxy-p-methylacetophenone: M.p. 80.3–81.0°С; lit21 82–
83°С. 1H NMR (CDCl3): d (ppm) 2.38 (s, 3H, CH3), 2.46 (s, 3H, CH3),
5.20 (s, 2H, CH2), 7.35 (d, J = 7.5 Hz, 2H, ArH), 7.42 (d, J = 8.0 Hz,
2H, ArH), 7.72 (d, J = 7.5 Hz, 2H, ArH), 7.85 (d, J = 8.0 Hz, 2H,
ArH). 13C NMR (CDCl3): d (ppm) 21.7, 21.7, 69.8, 126.4, 128.2,
129.2, 129.6, 130.0, 132.3, 132.6, 145.5, 189.8.
a-Tosyloxy-m-nitroacetophenone: M.p. 116.3–117.7°С; lit21 116–
1
117°С. H NMR (CDCl3): d (ppm) 2.46 (s, 3H, CH3), 5.26 (s, 2H,
CH2), 7.37 (d, J = 10.0 Hz, 2H, ArH), 7.68–7.74 (m, 1H, ArH), 7.84
(d, J = 10.0 Hz, 2H, ArH), 8.21–8.22 (m,1H, ArH) 8.45–8.48 (m,
1H, ArH), 8.63–8.64 (m, 1H, ArH). 13C NMR (CDCl3): d (ppm) 21.7,
69.9, 123.1, 128.2, 128.3, 130.1, 130.3, 132.3, 133.8, 135.1, 145.7,
148.5, 189.2.
Ethyl a-tosyloxyacetoacetate: Oil.36 1H NMR (CDCl3): d (ppm)
1.21 (t, J = 7.5 Hz, 3H, CH3), 2.30 (s, 3H, carbonyl-CH3), 2.46 (s,
3H, Ar-CH3), 4.16 (q, J = 7.5 Hz, 2H, CH2), 5.20 (s, H, CH), 7.37 (d,
J = 7.5 Hz, 2H, ArH), 7.83 (d, J = 7.5 Hz, 2H, ArH). 13C NMR
(CDCl3): d (ppm) 13.8, 21.7, 26.5, 61.4, 80.6, 128.3, 130.1, 132.3,
145.9, 163.5, 197.1.
General method of the regeneration and the reuse of ion-supported
HTIB 3 in [emim]BF4
As described in Method 2, after extraction with ether, the crude ionic
liquid [emim]BF4 containing ion-supported iodobenzene 1 (0.94–
0.97 or 1.90–1.94 mmol) and a small amount of ether was dried under
high vaccum (<5 mm Hg) for 12 h at 50°С. The resulting material
was then dissolved in acenitrile (10 mL), followed by addition of
PTSA monohydrate (1.0 or 2.0 mmol) and m-CPBA (1.0 or 2.0 mmol)
and the mixture was stirred for 1 h at 30°С under nitrogen protection.
The mixture was concentrated in vacuo to give a residue, which was
washed with ether (10 mL × 2) to remove the excess amount of PTSA
and m-CPBA. After drying under high vacuum, ion-supported HTIB
3 in [emim]BF4 was obtained, and could be used for the synthesis of
a-tosyloxylation of ketones.
This work was financially supported by the Natural Science
Foundation of the Jiangsu Higher Education Institutions of
China (No. 06JB150025).
Received 1 September 2009; accepted 14 November 2009
Paper 09/0771 doi: 10.3184/030823409X12590815399135
Published online: 8 December 2009
Characterisation
of
1-[4-hydroxyl(tosyloxy)-iodobenzyl]-3-
References
methylimidazolium tetrafluoroborate (3): 1H NMR (500 MHz,
DMSO-d6): d (ppm) 2.29 (s, 3H, Ar-CH3), 3.84 (s, 3H, imidazolium-
CH3), 5.38 (s, 2H, CH2), 7.13 (d, J = 8.0 Hz, 2H, ArH), 7.23 (d,
J = 8.0 Hz, 2H, ArH), 7.51 (d, J = 8.0 Hz, 2H, ArH), 7.71 (s, 1H,
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d (ppm) 21.0, 36.2, 51.6, 95.5, 122.6, 124.3, 125.8, 128.3, 130.9,
134.8,137.1, 138.0, 138.2, 145.6. IR (Nujol): 3445 (–OH), 3155,
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PAPER: JC090771
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