Xiang et al.
FULL PAPER
aldehyde and acetone to produce cyclohex-2-enone.[12]
In this paper, we described a new catalytic system of
L-lysine/imidazole for the direct synthesis of substituted
3-methylcyclohex-2-enone by a one-pot strategy.
light yellow solid. m.p. 43-47 ℃. 1H NMR (400 MHz,
CDCl3) δ: 7.22-7.12 (m, 2H), 7.06-6.96 (m, 2H),
5.96 (s, 1H), 3.33-3.25 (m, 1H), 2.58-2.46 (m, 4H),
1.99 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 198.4,
162.7, 161.2, 138.9, 128.1, 126.8, 115.0, 43.8, 39.8,
38.9, 24.1; IR (KBr) v: 3041, 2916, 1666, 1602, 1511,
1225, 890 cm−1.
Scheme 2 Synthetic route to cyclohexanone-2-ene
acetone
5-(4'-Chloropheny1)-3-methylcyclohex-2-enone
CAS No: 54795-01-6, 5d: Yield: 15.4 mg (35%); light
yellow solid. m.p. 53-55 ℃. H NMR (400 MHz,
CDCl3) δ: 7.30 (d, J=8.4 Hz, 2H), 7.17 (d, J=8.4 Hz,
2H), 5.97 (s, 1H), 3.34-3.26 (m, 1H), 2.64-2.47 (m,
4H), 2.00 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 199.2,
161.7, 143.3, 128.8, 127.0, 126.8, 126.6, 43.9, 40.8,
39.0, 24.4; IR (KBr) v: 3031, 1663, 1633, 1594, 1490,
1379, 827 cm−1.
Path a
O
O
1
acetone
R
R
R
O
acetone
Path b
Experimental
5-(2'-Chloropheny1)-3-methylcyclohex-2-enone
CAS No: 10323-89-4, 5e: Yield: 15.8 mg (36%); light
General
1
All reagents were purchased from commercial
sources and used without treatment, unless otherwise
indicated. The products were purified by column chro-
yellow solid. m.p. 61-64 ℃. H NMR (400 MHz,
CDCl3) δ: 7.33 (d, J=8.0 Hz, 1H), 7.25-7.14 (m, 2H),
7.40 (d, J=8.0 Hz, 1H), 5.92 (s, 1H), 3.81-3.73 (m,
1H), 2.59-2.43 (m, 4H), 1.95 (s, 3H); 13C NMR (100
MHz, CDCl3) δ: 198.5, 161.3, 142.1, 131.8, 128.4,
127.5, 127.3, 126.5, 120.6, 43.5, 40.1, 38.6, 24.3; IR
(KBr) v: 3058, 1669, 1633, 1612, 1475, 1380, 696, 754
cm−1. HR-MS [EI]+ calcd for C13H13ClO: 220.0656;
found 220.0655.
matography over silica gel. H and 13C NMR spectra
1
were recorded on a Bruker AVANCE DMX-500 spec-
trometer at 400 MHz and 100 MHz in CDCl3, respec-
tively. Chemical shifts are reported relative to the inter-
nal standard of tetramethylsilane (TMS). IR spectra
were measured with a Nicolet Nexus FTIR 670 spec-
trophotometer. HR-MS were obtained on a Bruker
7-Tesla FT-ICR MS equipped with an electrospray
source (Billelica, MA, USA).
5-(3'-Chloropheny1)-3-methylcyclohex-2-enone
CAS No: 10323-90-7, 5f: Yield: 20.7 mg (47%); light
1
yellow liquid. H NMR (400 MHz, CDCl3) δ: 7.39-
7.37 (m, 2H), 7.22-7.14 (m, 2H), 5.96 (s, 1H), 3.34-
3.25 (m, 1H), 2.60-2.46 (m, 4H), 2.00 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ: 198.7, 161.5, 140.1, 136.4,
129.9, 128.0, 127.2, 127.0, 126.4, 42.2, 37.1, 29.6, 24.3;
IR (KBr) v: 3031, 2917, 1664, 1625, 1593, 1430, 888
cm−1.
Syntheses
A mixture of 1a-1m (0.20 mmol), acetone (0.4
mL), imidazole (0.18 mmol), L-lysine (0.06 mmol) and
water (10 μL) was added to n-heptane (2 mL) and it was
stirred at 50 ℃ for 36 h. After the completion of the
reaction, the yields were detected by HPLC using
area-external standard method.
5-(4'-Nitropheny1)-3-methylcyclohex-2-enone CAS
No: 62596-10-5, 5a: Yield: 37.9 mg (82%); light yellow
solid. m.p. 131-135 ℃. 1H NMR (400 MHz, CDCl3) δ:
8.23 (d, J=8.8 Hz, 2H), 7.43 (d, J=8.4 Hz, 2H), 6.03
(s, 1H), 3.48-3.42 (m, 1H), 2.71-2.56 (m, 4H), 2.05
(s, 3H); 13C NMR (100 MHz, CDCl3) δ: 197.6, 160.8,
150.5, 147.1, 127.7, 126.7, 124.1, 43.2, 40.5, 38.2, 24.3;
IR (KBr) v: 3060, 3029, 1661, 1606, 1596, 1521, 1346,
853 cm−1.
5-(4'-Bromopheny1)-3-methylcyclohex-2-enone CAS
No: 211876-67-4, 5g: Yield: 22.3 mg (42%); white solid.
m.p. 66-69 ℃. 1H NMR (400 MHz, CDCl3) δ: 7.47 (d,
J=8.4 Hz, 2H), 7.13 (d, J=8.4 Hz, 2H), 5.99 (s, 1H),
3.33-3.26 (m, 1H), 2.66-2.48 (m, 4H), 2.02 (s, 3H);
13C NMR (100 MHz, CDCl3) δ: 161.3, 142.1, 131.8,
128.4, 126.5, 120.6, 98.5, 43.5, 40.1, 38.6, 24.3; IR
(KBr) v: 3030, 2915, 1663, 1634, 1488, 1379, 890 cm−1.
5-(4'-Cyanopheny1)-3-methylcyclohex-2-enone 5h:
Yield: 27.4 mg (65%); light yellow solid. m.p. 55-59
1
℃. H NMR (400 MHz, CDCl3) δ: 7.65 (d, J=8.0 Hz,
5-(3'-Nitropheny1)-3-methylcyclohex-2-enone CAS
No: 10323-98-5, 5b: Yield: 33.3 mg (72%); light yellow
solid. m.p. 100-105 ℃. 1H NMR (400 MHz, CDCl3) δ:
8.15-8.13 (m, 2H), 7.60 (d, J=8.0 Hz, 1H), 7.61-
7.52 (m, 1H), 6.02 (s, 1H), 3.52-3.44 (m, 1H), 2.68-
2.56 (m, 4H), 2.05 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ: 197.8, 160.9, 148.5, 145.1, 133.0, 129.8, 126.7, 122.1,
121.7, 43.3, 40.3, 38.3, 24.3; IR (KBr) v: 3069, 2922,
1662, 1633, 1528, 1352, 887 cm−1.
2H), 7.37 (d, J=7.6 Hz, 2H), 6.01 (s, 1H), 3.48-3.36
(m, 1H), 2.68-2.51 (m, 4H), 2.03 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ: 197.73, 160.78, 148.45, 132.60,
127.57, 126.68, 118.55, 110.97, 43.31, 40.38, 38.48,
24.45; IR (KBr) v: 3036, 2921, 2227, 1664, 1635, 1608,
1380, 891 cm−1. HR-MS [EI]+ calcd for C14H13NO:
211.0997; found 211.0996.
5-(4'-Trifluoromethylpheny1)-3-methylcyclohex-2-
enone 5i: Yield: 46.7 mg (92%); light yellow liquid. 1H
NMR (400 MHz, CDCl3) δ: 7.59 (d, J=8.0 Hz, 2H),
7.35 (d, J=8.0 Hz, 2H), 5.99 (s, 1H), 3.44-3.34 (m,
5-(4'-Fluoropheny1)-3-methylcyclohex-2-enone
CAS No: 1222312-10-8, 5c: Yield: 22.4 mg (55%);
998
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 997—1002