EXPERIMENTAL
Melting points were determined with a capillary apparatus and uncorrected. NMR spectra were recorded on a 300MHz spectrometer with chemical shift values reported in units (ppm) relative to an internal standard (TMS). IR spectra were obtained on SIMADZU FT-IR 8400s spectrophotometer. The open-bed chromatography was carried out on silica gel (70−230 mesh, Merck) using gravity flow. The column was packed with slurries made from the elution solvent.
- General Procedure for the Conversion of Aldehydes and Ketones to Oximes
A mixture of carbonyl compound (
1a
−
1l
, 8.3 mmol), hydroxylamine hydrochloride (8.4 mmol), K
2
CO
3
(9.1 mmol) and MeOH (40 ml) was stirred at until the carbonyl compound was disappeared at reflux temperature or at room temperature. After cooling to room temperature, ketoximes
2a
−
2f
were extracted with dichloromethane (30 × 5 mL). The organic layer was separated and dried over anhydrous MgSO
4
. After evaporating the solvent under reduced pressure at below 20 ℃, the isomers were then separated from the resulting residue by column chromatography [
n
-hexane : ethyl acetate = 3 : 1 (v/v)] to give the corresponding
E
- and
Z
-ketoximes. (Caution:
E
- ketoxime is evaporating the solvent below 20 ℃. And store in freezer).
In the case of aldoximes, the solvent was evaporated under reduced pressure. The resulting residue was washed with cold diethyl ether (150 mL). The ether solutions were combined, and evaporated under reduced pressure. The isomers were then separated by column chromatography [
n
-hexane : ethyl acetate = 3 : 1 (v/v)] to give the corresponding
E
- and
Z
-aldoximes.
(E)-Acetophenone oxime (E-2a)
Mp 75−76 ℃ (lit.
18
80−81 ℃); R
f
= 0.23 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3193, 3083, 3053, 3030, 2967, 2920, 2868, 1468, 1436, 1375, 1301, 1267, 1021, 950, 759, 693, 621 cm
−1
;
1
H NMR (300 MHz, CDCl
3
): δ 3.31 (s, 3H), 7.36−7.42 (m, 3H), 7.60−7.64 (m, 2H);
13
C NMR (75 MHz, CDCl
3
): δ 12.37, 126.0, 128.5, 129.3, 136.4, 156.1; HRMS(EI):
m/z
calcd for C
8
H
9
NO: 135.0684; found: 135.0684.
(Z)-Acetophenone oxime (Z-2a)
Mp 52−54 ℃ (lit.
19
52−55 ℃); R
f
= 0.3 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3292, 3245, 3064, 2926, 1496, 1446, 1370, 1302, 1265, 1079, 1006, 926, 762, 744 cm
−1
;
1
H NMR (300 MHz, CDCl
3
): δ 2.30 (s, 3H), 7.36 (m, 3H), 7.60−7.62 (m, 2H), 9.86 (s, OH, D
2
O exchangeable );
13
C NMR (75 MHz, CDCl
3
): δ 12.42, 126.0, 128.5, 129.2, 136.4, 155.9; HRMS (EI):
m/z
calcd for C
8
H
9
NO: 135.0684; found: 135.0684.
(E)-4-Bromoacetophenone oxime (E-2b)
Mp 115−116 ℃; R
f
= 0.2 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3199, 3087, 3054, 2090, 2869, 2838, 1585, 1488, 1460, 1423, 1392, 1264, 1089, 1029, 1010, 942, 820, 748 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : δ 2.27 (s, 3H), 7.25−7.56 (m, 4H);
13
C NMR (75 MHz, CDCl
3
): δ 12.22, 123.6, 127.6, 131.6, 135.2, 155.2(9); HRMS (EI):
m/z
calcd for C
8
H
8
NOBr: 212.9789; found: 212.9793.
(Z)-4-Bromoacetophenone oxime (Z-2b)
Mp 124−126 ℃; R
f
= 0.48 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3286, 3246, 3082, 3009, 3956, 2914, 1484, 1394, 1309, 1274, 1182, 1069, 1008, 929, 825, 750 cm
−1
;
1
H NMR (300 MHz, CDCl
3
): δ 2.27 (s, 3H), 7.24−7.52 (m, 4H), 8.72 (s, OH D
2
O exchangeable);
13
C NMR (75 MHz, CDCl
3
): δ 12.25, 123.6, 127.6, 131.7, 135.2, 155.2(5); HRMS (EI): m/z calcd for C
8
H
8
NOBr: 212.9789; found: 212.9793.
(E)-3,4-Dimethoxyacetophenone oxime (E-2c)
Mp 45−47 ℃; R
f
= 0.11 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3249, 3005, 2954, 2921, 2851, 1517, 1463, 1416, 1367, 1274, 1260, 1225, 1175, 1148, 1024, 948, 869, 804, 764, 749 cm
−1
;
1
H NMR (300 MHz, DMSO-
d6
) : δ 2.10 (s, 3H), 3.75 (d, 6H,
J
= 9.9 Hz), 6.95−7.31 (m, 3H), 10.59 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, DMSO-
d6
) : δ 21.87, 55.39, 55.45, 110.9, 111.6, 112.3, 121.3, 147.7, 150.1, 158.1; HRMS(EI):
m/z
calcd for C
10
H
13
NO
3
: 195.0895; found: 195.0899.
(Z)-3,4-Dimethoxyacetophenone oxime (Z-2c)
Mp 141−143 ℃; R
f
= 0.17 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3432, 3084, 3011, 2975, 2928, 2843, 1583, 1515, 1503, 1456, 1441, 1332, 1296, 1272, 1241, 1222, 1173, 1149, 1079, 1016, 998, 950, 869, 812, 766 cm
−1
;
1
H NMR (300 MHz, DMSO-
d6
) : δ 2.14 (s, 3H), 3.77 (s, 6H), 6.93−6.95 (m, 1H), 7.14−7.17 (m, 1H), 7.28(2)−7.28(4) (m, 1H), 11.03 (s, OH D
2
O exchangeable);
13
C NMR (75 MHz, DMSO-
d6
): δ 11.33, 55.22, 55.38, 108.2, 111.1, 118.4, 129.5, 148.4, 149.4, 152.3; HRMS(EI):
m/z
calcd for C
10
H
13
NO
3
: 195.0895; found: 195.0899.
(E)-4-Methylpentan-2-one oxime (E-2d)
Liquid; R
f
= 0.35 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 1341, 1265, 1215, 1165, 1108, 1017, 955, 803, 751 cm
−1
;
1
H NMR (300 MHz, CDCl
3
): δ 0.94 (d, 6H,
J
= 6.6 Hz), 1.86(0)−1.86(9) (m, 4H), 2.25 (d, 2H,
J
= 7.5 Hz), 8.56 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, CDCl
3
): δ 14.10, 25.73, 26.90, 37.44, 158.3; HRMS(EI):
m/z
calcd for C
6
H
13
NO: 115.0997; found: 115.1008.
(Z)-4-Methylpentan-2-one oxime (Z-2d)
Liquid; R
f
= 0.55 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3422, 2958, 2375, 1629, 1464, 1374, 1112, 974, 931, 875, 832, 736 cm
−1
;
1
H NMR (300 MHz, CDCl
3
): δ 0.91 (d, 6H,
J
= 6.6 Hz ), 1.82−1.94 (m, 4H), 2.06 (d, 2H,
J
= 7.2 Hz), 9.74 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, CDCl
3
): δ 13.56, 22.36, 25.85, 44.75, 157.9; HRMS(EI):
m/z
calcd for C
6
H
13
NO: 115.0997; found: 115.1008.
Cyclohexanone oxime (2e)
Mp 85−87 ℃ (lit.
20
85−87 ℃); R
f
= 0.5 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3232, 3114, 2933, 2856, 2729, 1600, 1477, 148, 1249, 1222, 991, 958, 896, 763, 655, 565, 474 cm
−1
;
1
H NMR (300 MHz, CDCl
3
): δ 1.56−1.71 (m, 6H), 2.20−2.25 (m, 2H), 2.49−2.53 (m, 2H), 8.54 (s, 1H);
13
C NMR (75 MHz, CDCl
3
): δ 24.51, 25.57, 25.77, 26.86, 32.08, 160.89; HRMS (EI):
m/z
calcd for C
6
H
11
NO: 113.0841; found: 113.0848.
Benzophenone oxime (2f)
Mp 136−137 ℃ (lit.
21
138−142 ℃); R
f
= 0.45 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3253, 3055, 2953, 2923, 2854, 1448, 1327, 1077, 1032, 997, 919, 766, 697 cm
−1
;
1
H NMR (300 MHz, DMSO-
d6
): δ 7.26−7.29 (m, 2H), 7.37−7.38 (m, 5H), 7.41−7.49 (m, 3H), 11.34 (s, 1H);
13
C NMR (75 MHz, DMSO-
d
6
): δ 127.4, 128.6, 128.8(0), 128.8(4), 129.3, 133.9, 137.1, 147.3, 155.6; HRMS(EI):
m/z
calcd for C
13
H
11
NO: 197.0841; found: 197.0844.
(E)-Benzaldehyde oxime (E-2g)
Mp 113−115 ℃; R
f
= 0.4 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3461, 3156, 2923, 2854, 1639, 1433, 1351, 1268, 954, 850, 754, 691 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : δ 7.36 (s, 1H), 7.39−7.47 (m, 3H), 7.91−7.97 (m, 2H), 8.35 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, CDCl
3
): δ 128.4, 130.1, 130.3, 130.8, 147.0; HRMS(EI):
m/z
calcd for C
7
H
7
NO: 121.0528; found: 121.0529.
(Z)-Benzaldehyde oxime (Z-2g)
Liquid; R
f
= 0.57 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3388, 2896, 2771, 1954, 1895, 1692, 1634, 1497, 1449, 1292, 1211, 956, 869, 756 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : δ 7.32−7.36 (m, 3H), 7.53−7.58 (m, 2H), 8.18 (s, 1H), 9.95 (s, OH, D
2
O exchangeable );
13
C NMR (75 MHz, CDCl
3
): δ 127.0, 128.7, 130.0, 131.6, 150.5; HRMS (EI):
m/z
calcd for C
7
H
7
NO: 121.0528; found: 121.0529.
(E)-4-Methoxybenzaldehyde oxime (E-2h)
Mp 84−85 ℃ (lit.
22
74 ℃ ); R
f
= 0.38 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3173, 3069, 3009, 2925, 2837, 2793, 1599, 1506, 1448, 1406, 1351, 1301, 1257, 1172, 1113, 1022, 951, 827, 743 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : δ 3.83 (s, 3H), 6.90−6.96 (m, 2H), 7.31 (s, 1H), 7.92−7.96 (m, 2H), 8.98 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, CDCl
3
): δ 55.31, 113.7, 132.0, 132.4, 146.3, 160.6; HRMS (EI):
m/z
calcd for C
8
H
9
NO
2
: 151.0633; found: 151.0631.
(Z)-4-Methoxybenzaldehyde oxime (2h)
Mp 44−46 ℃; R
f
= 0.43 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3301, 3005, 2963, 2937, 2910, 2838, 1607, 1575, 1515, 1463, 1418, 1304, 1252, 1109, 1029, 957, 874, 829 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : δ 3.81 (s, 3H), 6.09 (d, 2H,
J
= 8.76 Hz), 7.51 (d, 2H,
J
= 8.7 Hz), 8.11 (s, 1H), 9.03 (s, OH, D
2
O exchangeable );
13
C NMR (75 MHz, CDCl
3
): δ 55.31, 114.2, 124.5, 128.5, 149.8, 161.0; HRMS (EI):
m/z
calcd for C
8
H
9
NO
2
: 151.0633; found: 151.0631.
(E)-2-Methylbenzaldehyde oxime (E-2i)
Mp 88−89 ℃; R
f
= 0.28 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3191, 3086, 3030, 2987, 2866, 1656, 1600, 1437, 1328, 1275, 1260, 1217, 1037, 956, 939, 854, 764 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : ℃ 2.39 (s, 3H), 7.22−7.32 (m, 3H), 7.64 (s, 1H), 7.88−7.92 (m, 1H), 8.41 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, , CDCl
3
): ℃ 19.88, 125.6, 129.2, 129.6, 129.7, 130.4, 136.8, 146.3; HRMS (EI):
m/z
calcd for C
8
H
9
NO: 135.0684; found: 135.0683.
(Z)-2-Methylbenzaldehyde oxime (Z-2i)
Mp 46−48 ℃; R
f
= 0.43 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3317, 3069, 3022, 2984, 2922, 2779, 1622, 1489, 1457, 1433, 1312, 1292, 1226, 1125, 1034, 951, 871, 754, 716 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : ℃ 2.38 (s, 3H), 7.14−7.28 (m, 3H), 7.65−7.68 (m, 1H), 8.44 (s, 1H), 9.72 (s, OH, D
2
O exchangeable).
13
C NMR (75 MHz, CDCl
3
): ℃ 19.77, 126.3, 126.6, 130.0, 130.1, 130.9, 136.2, 149.3; HRMS (EI):
m/z
calcd for C
8
H
9
NO: 135.0684; found: 135.0683.
(E)-3-Bromobenzaldehyde oxime (E-2j)
Mp 98−100 ℃; R
f
= 0.25 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3170, 3069, 2840, 2746, 1949, 1685, 1644, 1559, 1463, 1415, 1330, 1269, 1191, 1073, 955, 917, 900, 877, 780, 749 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : ℃ 7.31−7.33 (m, 2H), 7.53−7.56 (m, 1H), 7.78−7.81 (m, 1H), 8.15−8.16 (m, 1H);
13
C NMR (75 MHz, CDCl
3
): ℃ 129.3, 130.0, 133.1, 133.6, 145.4; HRMS (EI):
m/z
calcd for C
7
H
6
NOBr: 189.9633; found: 189.9635.
(Z)-3-Bromobenzaldehyde oxime (Z-2j)
Mp 57−59 ℃; R
f
= 0.43 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3343, 3065, 2939, 2888, 2832, 2752, 1943, 1695, 1566, 1475, 1421, 1351, 1310, 1272, 1200, 1105, 1064, 976, 908, 875, 702 cm
−1
;
1
H NMR (300 MHz, CDCl
3
) : ℃ 7.23−7.28 (m, 1H), 7.47−7.53 (m, 2H), 7.74−7.75 (m, 1H), 8.08 (s, 1H), 8.19 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, CDCl
3
): ℃ 125.6, 129.7, 130.2, 132.9, 149.0; HRMS(EI):
m/z
calcd for C
7
H
6
NOBr: 189.9633; found: 189.9635.
(E)-4-Nitrobenzaldehyde oxime (E-2k)
Mp 157−159 ℃ (lit.
23
146 ℃); R
f
= 0.31 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3180, 3067, 3014, 2926, 2880, 2837, 2788, 1601, 1519, 1441, 1401, 1344, 1318, 1264, 1192, 1104, 1013, 967, 942, 909, 852, 840, 746 cm
−1
;
1
H NMR (300 MHz, DMSO-
d
6
): δ 7.67 (s, 1H), 8.21−8.24 (m, 2H), 8.29−8.32 (m, 2H), 12.27 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, DMSO-
d
6
): δ 123.6, 131.3, 136.2, 143.0, 147.0; HRMS (EI):
m/z
calcd for C
7
H
6
N
2
O
3
: 166.0378; found: 166.0378.
(Z)-4-Nitrobenzaldehyde oxime (Z-2k)
Mp 128−129 ℃ (lit
24
129 ℃); R
f
= 0.44 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3335, 3079, 2938, 1925, 1803, 1602, 1535, 1347, 1213, 1105, 969, 845, 746 cm
−1
;
1
H NMR (300 MHz, DMSO-
d6
) : δ 7.85−7.89 (m, 2H), 8.24−8.28 (m, 2H), 8.32 (s, 1H), 11.89 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, DMSO-
d6
): δ 123.9, 127.2, 139.4, 146.7, 147.4; HRMS (EI):
m/z
calcd for C
7
H
6
N
2
O
3
: 166.0378; found: 166.0378.
(E)-4-Cyanobenzaldehyde oxime (E-2l)
Mp 138−140 ℃; R
f
= 0.1 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3259, 2981, 2963, 2868, 2855, 2227, 1459, 1403, 1275, 1260, 1176, 1082, 916, 828, 763, 749, 704 cm
−1
;
1
H NMR (300 MHz, DMSO-
d6
) : δ 7.58 (s, 1H), 7.74 (d, 2H, J = 8.19 Hz), 8.13 (d, 2H,
J
= 8.49 Hz), 12.15 (s, OH, D
2
O exchangeable );
13
C NMR (75 MHz, DMSO-
d6
): δ 111.5, 126.9, 130.7, 132.3, 132.6, 143.4; HRMS (EI):
m/z
calcd for C
8
H
6
N
2
O: 146.0480; found: 146.0478.
(Z)-4-Cyanobenzaldehyde oxime (Z-2l)
Mp 171−173 ℃; R
f
= 0.2 (
n
-hexane : ethyl acetate = 3:1, v/v); IR (KBr): 3208, 3003, 2980, 2955, 2935, 2896, 2831, 2225, 1399, 1326, 1305, 1278, 1261, 1191, 1101, 1056, 971, 938, 873, 842, 824, 750, 702 cm
−1
;
1
H NMR (300 MHz, DMSO-
d
6
): δ 7.78 (d, 2H,
J
= 8.1 Hz), 7.87 (d, 2H,
J
= 8.1 Hz), 8.25 (s, 1H), 11.7 (s, OH, D
2
O exchangeable);
13
C NMR (75 MHz, DMSO-
d
6
): δ 111.2, 118.6, 126.9, 132.6, 137.5, 147.0; HRMS (EI):
m/z
calcd for C
8
H
6
N
2
O: 146.0480; found: 146.0478.
Robertson G. M.
1995
Imines and Their N-substituted Derivatives: Oximes and Their O-R Substituted Analogues, in Comprehensive Organic Functional Group Transformations; Katritzky, A. R.; Meth-Cohn, O.; Rees, C. W., Eds.
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Oxford
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,
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2005
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2000
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