Transform Amids to Esters by Chlorotrimethylsilane
J. Chin. Chem. Soc., Vol. 51, No. 2, 2004 361
2
0
+
with a 2m ´ 3mm column packed with SE-30 (5% on
Chromosorb W). GLC peak integrals were recorded by using
a Shimadzu Chromatopac C-R3A integrator. MS spectra
were determined on a Shimadzu QP-1000 spectrometer or
Fisons MD800 GC/MS or VG 70-250S spectrometer. The
Ethyl 2-phenylacetate: MS (m/z) 164 (M ), 91.
2
1 1
i-Propyl 2-phenylacetate: H-NMR (CDCl
3
, TMS) d
1.22 (d, J = 6 Hz, 6H), 3.57 (s, 2H), 5.00 (m, 1H), 7.28 (m,
1
3
3
5H) ppm; C-NMR (CDCl , TMS) d 21.73, 41.70, 68.14,
126.91, 128.46, 129.15, 134.31, 171.11 ppm; MS (m/z) 178
1
+
products were characterized by comparison of their H-NMR
(M ), 91.
1
3
22 1
and C-NMR as well as MS spectra with those of known
samples.
3
Ethyl 2-phenylpropanoate: H-NMR (CDCl , TMS) d
1.20 (t, J = 7 Hz, 3H), 1.49 (d, J = 7 Hz, 3H), 3.68 (q, J = 7 Hz,
1
3
1
H), 4.14 (q, J = 7 Hz, 2H), 7.28 (m, 5H) ppm; C-NMR
General Procedure for the Transformation of Amides
and Imides into the Corresponding Esters and Diesters
by using Chlorotrimethylsilane and Alcohols
(CDCl
3
, TMS) d 14.09, 18.58, 45.55, 60.70, 127.02, 127.44,
+
128.55, 140.68, 174.54 ppm; MS (m/z) 178 (M ), 105.
2
3
1
i-Propyl 2-phenylpropanoate:
3
H-NMR (CDCl ,
TMSCl (1.27 mL, 10 mmol) was added dropwise into
the reaction mixture of benzamide (0.6 g, 5 mmol), and EtOH
TMS) d 1.13 (d, J = 6 Hz, 3H), 1.21 (d, J = 6 Hz, 3H), 1.48 (d,
J = 6 Hz, 3H), 3.66 (q, J = 6 Hz, 1H), 4.95-5.05 (m, 1H),
1
3
(
2.34 mL, 40 mmol) in a dry flask under nitrogen atmosphere
at room temperature. The reaction mixture was then heated to
0 °C for 5 h. Excess alcohol was distilled out under reduced
3
7.20-7.40 (m, 5H) ppm; C-NMR (CDCl , TMS) d 18.52,
21.53, 21.72, 45.74, 67.90, 126.93, 127.42, 128.49, 140.81,
+
4
174.05 ppm; MS (m/z) 192 (M ), 105.
2
4 1
pressure. After being cooled to room temperature, chloro-
form (15 mL) and hexane (15 mL) were added and the solu-
tion was filtered through a silica gel bed. The filtrate was con-
centrated at reduced pressure to afford ethyl benzoate in 91%
yield and with GC purity ³ 98%.
2-Ethylhexyl acetate:
3
H-NMR (CDCl , TMS) d
0.88-0.92 (m, 6H), 1.23-1.42 (m, 9H), 2.05 (s, 3H), 3.98 (d, J
+
= 6 Hz, 2H) ppm; MS (m/z) 172 (M ), 157, 154, 144, 112.
1
13
Selected H-, C-NMR, and MS spectral data of esters:
ACKNOWLEDGMENT
1
2
+
Ethyl benzoate: MS (m/z) 150 (M ), 122, 105, 77.
1
3 1
i-Propyl benzoate: H-NMR (CDCl
3
, TMS) d 1.38 (d,
The authors thank Academia Sinica and the National
Science Council of the Republic of China for financial
support.
J = 6 Hz, 6H), 5.21-5.30 (m, 1H), 7.42 (t, J = 7 Hz, 2H), 7.54
1
3
(
(
t, J = 7 Hz, 1H), 8.03 (d, J = 7 Hz, 2H) ppm; C-NMR
CDCl
3
, TMS) d 21.93, 68.31, 128.23, 129.48, 131.05,
+
1
32.66, 166.11 ppm; MS (m/z) 164 (M ), 123, 105.
1
4
1
Ethyl pyridine-3-carboxylate:
3
H-NMR (CDCl ,
Received May 23, 2003.
TMS) d 1.42 (t, J = 7 Hz, 3H), 4.42 (q, J = 7 Hz, 2H), 7.39 (dd,
J = 8, 5 Hz, 1H), 8.30 (d, J = 8 Hz, 1H), 8.77 (dd, J = 5, 2 Hz,
+
1
1
H), 9.22 (d, J = 2 Hz, 1H) ppm; MS (m/z) 151 (M ), 129,
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06.
1
5 1
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1
2
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6 1
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2
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1
7 1
3
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5
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1
8 1
3
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6
(
(
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1
+
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1
9 1
3
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8
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=
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+
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(
m/z) 160 (M ), 133, 115, 88.