Synthesis of amino ketones containing organosilicon groups: Catalytic enantioselective three-component Mannich-type reaction

Article abstract of DOI:10.3184/174751912X13450464806822

Aldimines, generated in situ from 4-[2,2-bis(trimethylsilyl)ethenyl] benzaldehyde and aromatic amines, undergo Mannich-type reactions with cyclic and acyclic ketones. The one-pot reaction is efficiently catalysed by zirconium oxychloride (ZrOCl8H₂

Full text of DOI:10.3184/174751912X13450464806822

JOURNAL OF CHEMICAL RESEARCH 2012
RESEARCH PAPER 575
OCTOBER, 575–578
Synthesis of β-amino ketones containing organosilicon groups: catalytic
enantioselective three-component Mannich-type reaction
Kazem D. Safa*, Mahtab Abolfathi and Khatereh Ghorbanpour
Organosilicon Research Laboratory, Faculty of Chemistry, University ofTabriz, 5166616471Tabriz, Iran
Aldimines, generated in situ from 4-[2,2-bis(trimethylsilyl)ethenyl]benzaldehyde and aromatic amines, undergo
Mannich-type reactions with cyclic and acyclic ketones. The one-pot reaction is efficiently catalysed by zirconium
oxychloride (ZrOCl2.8H2O) at room temperature. β-Amino carbonyl compounds containing bis(trimethylsilyl)ethenyl
groups are obtained in acceptable to good yields with moderate to high stereoselectivity under solvent-free
conditions.
Keywords: vinylbis(silanes), Mannich-type reaction, β-amino ketones, zirconium oxychloride
Despite many publications describing applications of organo-
silicon chemistry in synthesis, few involve vinylsilanes.1–3
We have, however, shown that readily available compounds
of this type may be used to develop ways of making new
carbon–carbon bonds in a range of organosilicon compounds
containing a wide range of functional groups.4–7
Previously, we described the synthesis of bis(trimethylsilyl)-
ethenyl derivatives containing imine and amine groups.7 We
have now used Mannich-type reactions of aldehydes contain-
ing bis(trimethylsilyl)ethenyl groups to synthesise new β-ami-
noketones. These are attractive targets for chemical synthesis
because of their possible biological activity and potential
applications in the synthesis of pharmaceutical agents and
natural products.8–16
and cyclohexanone (Scheme 1) we carried out experiments
described in Table 1. These indicated that highest yields
and shortest reaction times were achieved under solvent-free
conditions (yield 90% in 15 minutes). Reactions in aqueous
or organic solvents gave lower yields together with the side-
product 4. The reaction in EtOH gave a high yield (70% in 1 h)
but in MeCN and EtOAc the imine 2 was isolated as sole
product after 15 minutes. Increasing the reaction time to 1 h
led to formation of compound 3b, together with a few percent
of 4. In water, the imine 2 was isolated as the main product
even after 1 day.
Table 1 Mannich reactions of 4-[2,2-bis(trimethylsilyl)ethenyl]
benzaldehyde (1 mmol), aniline (1 mmol), and cyclohexanone
(3 equiv.) in various solvents
As ZrOCl2.8H2O is reported to be an efficient Lewis acid
catalyst for the one-pot synthesis of β-aminoketones8,17,18
we chose it for our study of Mannich-type reactions between
4-[2,2-bis(trimethylsilyl)ethenyl]benzaldehyde (1), aromatic
amines, and ketones.
Solvent
Time
Yield/% a
(3b)
(4)
MeCN
EtOAC
EtOH
1 h
1 h
15 min
1 h
8 h
15 min
60
40
50
70
20
90
20
20
–
10
–
–
Results and discussion
Reactions were studied in various solvents and under solvent-
free conditions in the presence of 15 mol% ZrOCl2.8H2O
at room temperature with a very simple work-up procedure.
To find the optimal conditions for the reaction of 4-[2,2-bis
(trimethylsilyl)ethenyl]benzaldehyde7 with 4-chloroaniline
EtOH
H2O
Solvent-free
aYields obtained by PTLC.
Scheme 1 Mannich reaction of 4-[2,2-bis(trimethylsilyl)ethenyl]benzaldehyde with 4-chloroaniline and cyclohexanone.
* Correspondent. E-mail: dsafa@tabrizu.ac.ir

576 JOURNAL OF CHEMICAL RESEARCH 2012
Scheme 2 Mannich-type reaction of aldehyde 1 with aromatic amines and cyclic ketones.
In order to explore the generality and scope of the new
procedure, three-component one-pot Mannich type reactions
of aldehyde 1 with various aromatic amines and cyclic ketones
were tested under the conditions found to be optimal for
4-chloroaniline (Scheme 2). The results are summarised in
Table 2. All the reactions proceeded rapidly without solvent in
the presence of 15 mol% ZrOCl2.8H2O at room temperature
to give the corresponding β-aminoketones containing the [2,2-
bis(trimethylsilyl)ethenyl] group; yields were achieved good
to high anti stereoselectivity (Table 2). The anti and syn
isomers were identified by the coupling constants (J) of the
Conclusion
Three-component Mannich reactions of 4-[2,2-bis(trimethylsilyl)
ethenyl]benzaldehyde (1), anilines and ketones are efficiently
catalysed by ZrOCl2.8H2O under solvent-free conditions. The
present catalytic system provides an attractive protocol for the
synthesis of β-aminoketones containing bis(trimethylsilyl)ethenyl
groups summarised in the following points: (1) high yields; (2)
good stereoselectivities; (3) facile operations; (4) environmen-
tally benign reaction conditions; (5) highly efficient catalyst
activity; and (6) avoidance of the troublesome preparation of
enol derivatives and pre-formed imines.
1
vicinal protons adjacent to C=O and NH in their H NMR
spectra, as described in the literature.8,16 The value of J of the
anti isomer is higher than of the syn one.
Experimental
All chemicals were used as purchased. 4-[2,2-Bis(trimethylsilyl)-
ethenyl]benzaldehyde (1) was synthesised as described in the literature.7
NMR spectra were recorded with a Bruker FT-400 MHz spectrometer
at 400.13 (1H) and 100.61 (13C) MHz at room temperature. Except
where indicated, CDCl3 was used as solvent. The FTIR spectra
from KBr discs were recorded on a Bruker-Tensor 270 spectrometer.
Elemental analyses were obtained with a Vario EL III instrument.
The products were purified by PTLC on silica gel with hexane/ethyl
acetate as eluent. All compounds were characterised by spectroscopic
data and elemental analysis.
Similarly, Mannich reactions of aldehyde 1, anilines, and
acyclic ketones such as acetone and acetophenone were inves-
tigated. The overall reaction is best formulated in Scheme 3.
The time required for completion of reactions with acetophe-
none was longer than that for reactions with acetone.
Table 2 Yields and selectivity of direct Mannich-type reaction
of aldehyde 1 with various aromatic amines and cyclic ketones
without solvent
General reaction procedure
4-[2,2-Bis(trimethylsilyl)ethenyl]benzaldehyde (1 mmol), cyclohexa-
none (3 mmol), and ZrOCl2.8H2O (15 mol%) were added successively
to aniline (1 mmol) at room temp. (20–25 °C) and the mixture was
stirred for 10 min. Then CH2Cl2 (10 mL) was added, and the catalyst
removed by filtration. The filtrate was washed with saturated aqueous
NaHCO3 solution and brine, dried with anhydrous Na2SO4, and
solvent removed. The crude residue was purified by PTLC on silica
gel using hexane/ethyl acetate (10:2) to afford the product. Details are
given for each compound below.
Ketone
Amine
Product Time/
min
Yielda
/%
Anti/
Synb
n =1
n =1
n =1
n =1
n =1
n =1
n =1
n =1
n =1
n =2
n =2
C6H5NH2
4-ClC6H4NH2
3-ClC6H4NH2
3,4-Cl2C6H3NH2
4-FC6H4NH2
4-NO2C6H4NH2
4-MeC6H4NH2
4-nBuC6H4NH2
α-C10H7NH2
3a
3b
3c
3d
3e
3f
10
15
15
20
20
20
15
20
120
40
45
65
90
80
86
82
89
85
80
60
70
75
62:38
68:32
70:30
70:30
75:25
61:39
80:20
90:10
83:17
66:34
80:20
3g
3h
3i
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(phenylamino)methyl]
cyclohexanone (3a): Yellow viscous oil; yield 65% (anti/syn 62:38),
(silica gel, hexane/ethyl acetate 10:2, Rf = 0.72 ); FTIR (KBr, cm−1):
836, 1251 (SiCH3), 1494, 1603 (Ar), 1720 (CO), 2856, 2953, 3032
C6H5NH2
4-ClC6H4NH2
3j
3k
1
(CH), 3432 (NH); H NMR (DMSO): δ −0.12 (s, 9 H, SiMe3), 0.14
a Yields obtained by PTLC.
(s, 9 H, SiMe3), 1.17–2.35 (m, 8 H, CH2), 2.73 (s, br, 1 H, COCH,
anti+syn), 4.73 (s, br, CHN, anti), 4.80 (s, br, CHN, syn), 6.42–6.50
b anti/syn ratio determined from 1H NMR spectra.
Scheme 3 Mannich reaction of aldehyde 1, anilines and acyclic ketones.

JOURNAL OF CHEMICAL RESEARCH 2012 577
(m, 3 H, Ar), 6.92 (s, 2 H, Ar), 7.06 (s, 2 H, Ar), 7.27–7.43 (m, 2 H,
Ar), 7.69 (s, 1 H, HC=, anti+syn); 13C NMR (DMSO): δ 0.6, 1.9
(SiMe3), 23.1–55.6 (CH2), 56.5 (CN), 113.1–155.0 (Ar), 209.6, 210.9
(CO). Anal. Calcd for C27H39NOSi2: C, 72.10; H, 8.74; N, 3.11. Found:
C, 72.53; H, 8.93; N, 2.76%.
1 H, COCH, anti+syn), 4.60 (s, br, 1 H, NH), 4.74 (d, J = 7.6 Hz,
0.8 H, CHN, anti), 4.87 (d, J = 4.0 Hz, 0.2 H, CHN, syn), 6.57 (d,
J = 8.0 Hz, 2 H, Ar), 6.98 (d, J = 8.4 Hz, 2 H, Ar), 7.25 (d, J = 7.6 Hz,
2 H, Ar), 7.42 (d, J =8.0 Hz, 2 H, Ar), 7.84 (s, 1 H, HC= anti+syn); 13
C
NMR: δ −0.5, 0.6 (SiMe3), 19.3–56.4 (CH2), 57.0 (CN), 113.0–153.6
(Ar), 210.4, 211.8 (CO). Anal. Calcd for C28H41NOSi2: C, 72.51; H,
8.91; N, 3.02. Found: C, 72.21; H, 8.93; N, 2.69%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(4-chlorophenylamino)
methyl]cyclohexanone (3b): Brown viscous oil; yield 90% (anti/syn
69:31), (silica gel, hexane/ethyl acetate 10:3, Rf = 0.5), FTIR (KBr,
cm−1): 838, 1250 (SiCH3), 1499, 1603 (Ar), 1706 (CO), 2945 (CH),
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(4-butylphenylamino)
methyl]cyclohexanone (3h):Yellow solid; yield 80% (anti/syn 90:10),
(silica gel, hexane/ethyl acetate 10:2, Rf = 0.65), m.p. 90–93˚C. FTIR
(KBr, cm−1): 838, 1248 (SiMe3), 1517, 1616 (Ar), 1707 (CO), 2859,
2931, 2953, 3019 (CH), 3405 (NH); 1H NMR: δ 0.05 (s, 9 H, SiMe3),
0.31 (s, 9 H, SiMe3), 1.02 (t, J = 6.4 Hz, 3 H, Bu), 1.40–1.47 (m, 2 H,
Bu), 1.58–1.65 (m, 2 H, Bu), 1.75–2.04 (m, 6 H, CH2), 2.47–2.57 (m,
4 H, CH2CO + Bu), 2.83–3.01 (m, 1 H, COCH, anti+syn), 4.59 (s, br,
1 H, NH), 4.74 (d, J = 6.8 Hz, 0.9 H, CHN, anti), 4.88 (d, J = 4.0 Hz,
0.1 H, CHN, syn), 6.58 (d, J = 7.2 Hz, 2 H, Ar), 6.99 (d, J = 6.8 Hz,
2 H, Ar), 7.25 (d, J = 6.8 Hz, 2 H, Ar), 7.4 (d, J = 7.2 Hz, 2 H, Ar), 7.85
(s, 1 H, HC=, syn+anti); 13C NMR: δ −0.5, 0.9 (SiMe3), 12.9–57.0
(CH2), 112.9–153.6 (Ar), 210.4, 211.8 (CO). Anal. Calcd for
C31H47NOSi2: C, 73.60; H, 9.36; N, 2.77. Found: C, 73.31; H, 9.29; N,
2.32%.
1
3422 (NH); H NMR: δ −0.11 (s, 9 H, SiMe3), 0.16 (s, 9 H, SiMe3),
1.57–2.40 (m, 8 H, CH2), 2.42–2.47 (m, 1 H, COCH, syn+anti), 4.52
(d, J = 7.6 Hz, 0.68 H, CHN, anti), 4.69 (d, J = 4.0 Hz, 0.32 H, CHN,
syn), [6.44 (d, J = 8.8 Hz), 6.52 (d, J = 8.4 Hz,), 2 H, Ar, anti+syn],
6.97-7.28 (m, 7 H, Ar), 7.68 (s, 1 H, HC=, anti+syn); 13C NMR: δ
−0.5, 0.9 (SiCH3), 21.8-56.7 (C), 58.0 (CN), 114.5-153.3 (Ar), 210.4
and 211.9 (CO). Anal. Calcd for C27H38ClNOSi2: C, 66.97; H, 7.91; N,
2.89. Found: C, 66.65; H, 8.13; N, 2.53%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(3-chlorophenylamino)
methyl]cyclohexanone (3c): Yellow viscous oil; yield 80% (anti/syn
70:30), (silica gel, hexane/ethyl acetate 10:2, Rf = 0.86), FTIR (KBr,
cm−1): 839, 1250 (SiMe3), 1498, 1599 (Ar), 1707 (CO), 2858, 2923
1
(CH), 3425 (NH); H NMR: δ −0.19 (s, 9 H, SiMe3), 0.08 (s, 9 H,
SiMe3), 1.48–2.37 (m, 8 H, CH2), 2.63–2.67 (m, 1 H, COCH, anti+
syn), 4.48 (d, J = 7.2 Hz, 0.7 H, CHN, anti), 4.65 (s, 0.3 H, CHN, syn),
6.29–6.49 (m, 3 H, Ar), 6.82–7.20 (m, 5 H, Ar), 7.60 (s, 1 H, HC=,
anti+syn); 13C NMR: δ −0.72, 0.68 (SiMe3), 22.5–56.0 (CH2) 56.4
(CN), 110.8–153.2 (Ar), 209.9, 211.2 (CO). Anal. Calcd for
C27H38ClNOSi2: C, 66.97; H, 7.91; N, 2.89. Found: C, 66.35; H, 8.20;
N, 2.76%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(3,4-dichlorophenyl-
amino)methyl]cyclohexanone (3d): White solid; yield 86% (anti/syn
70:30), (silica gel, hexane/ethyl acetate 10:2, Rf = 0.58), m.p. 105–
107 °C; FTIR (KBr, cm−1): 840, 1249 (SiMe3), 1495, 1598 (Ar), 1704
(CO), 2861, 2943 (CH), 3407 (NH); 1H NMR: δ −0.10 (s, 9 H, SiMe3),
0.16 (s, 9 H, SiMe3), 1.53–2.00 (m, 6 H, CH2), 2.25–2.45 (m, 2 H,
CH2CO), 2.68–2.78 (m, 1 H, COCH, anti+syn), 4.49 (d, J = 7.2 Hz,
0.7 H, CHN, anti), 4.66 (d, J = 3.2 Hz, 0.3 H, CHN, syn), 4.80 (s, br,
1 H, NH), 6.33–6.36 (m, 1 H, Ar), [6.56 (d, J = 2.8 Hz, anti) and 6.57
(d, J = 2.7 Hz, syn), 1 H, Ar], 7.02–7.25 (m, 5 H, Ar), 7.69 (s, 1 H,
HC=, anti+syn); 13C NMR: δ −0.6, 0.9 (SiMe3), 22.7–56.4 (CH2),
57.1 (CN), 112.6–153.2 (Ar), 210.3, 211.6 (CO). Anal. Calcd for
C27H37Cl2NOSi2: C, 62.52; H, 7.19; N, 2.70. Found: C, 62.55; H, 7.40;
N, 2.56%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(naphth-1-ylamino)
methyl]cyclohexanone (3i): Brown viscous oil; yield 60% (anti/syn
83:17), (silica gel, hexane/ethyl acetate 10:2, Rf = 0.75), FTIR (KBr,
cm−1): 840, 1250 (SiMe3), 1527, 1580, 1630 (Ar), 1703 (CO), 2860,
2943, 3056 (CH), 3430 (NH); 1H NMR: δ −0.11 (s, 9 H, SiMe3), 0.15
(s, 9 H, SiMe3), 1.66–2.06 (m, 6 H, CH2), 2.34–2.45 (m, 2 H, CH2CO),
2.86–2.91 (m, 1 H, COCH, anti+syn), 4.76 (d, J = 6.8 Hz, 0.83 H,
CHN, anti), 4.90 (s, 0.17 H, CHN, syn), 5.60 (s, br, 1 H, NH), 6.34 (d,
J = 7.2 Hz, 1 H, Ar), 7.06–7.15 (m, 4 H, Ar), 7.34 (d, J = 8.0 Hz, 2 H,
Ar), 7.42–7.49 (m, 4 H, Ar), 7.69 (s, 1 H, HC=, syn+anti); 13C NMR:
δ −0.3, 0.9 (SiMe3), 22.3–57.1 (CH2), 105.1–153.4 (Ar), 200.6, 212.4
(CO). Anal. Calcd for C31H41NOSi2: C, 74.49; H, 8.27; N, 2.80. Found:
C, 74.68; H, 8.56; N, 2.46%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(phenylamino)methyl]
cycloheptanone (3j): Yellow viscous oil; yield 70% (anti/syn 66:34),
(silica gel, hexane/ethyl acetate, 10:2, Rf = 0.65); FTIR (KBr, cm−1):
838, 1251 (SiMe3), 1503, 1555, 1603 (Ar), 1694 (CO), 2857, 2928,
3052 (CH), 3411 (NH); 1H NMR: δ −0.05 (d, J = 8 Hz, 9 H, SiMe3),
0.21 (s, 9 H, SiMe3), 1.72–2.77 (m, 10 H, CH2), 2.88–2.95 (m, 1 H,
COCH, anti+syn), 4.53 (d, J = 7.2 Hz, 0.66 H, CHN, anti), 4.59 (d,
J = 4.4 Hz, 0.34 H, CHN, syn), 5.00 (s, br, 1 H, NH), 6.55 (d, J =
8.4 Hz, 2 H, Ar), 7.09–7.34 (m, 7 H, Ar), 7.74 (s, 1 H, HC=, anti+syn);
13C NMR: δ −0.25, 0.9 (SiMe3), 23.3–59.2 (CH2) 112.5–153.4 (Ar),
214.7, 215.4 (CO). Anal. Calcd for C28H41NOSi2: C, 72.51; H, 8.91; N,
3.02. Found: C, 72.34; H, 9.24; N, 2.66%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(4-fluorophenylamino)
methyl]cyclohexanone (3e): Brown viscous oil; yield 82% (anti/syn
75:25), (silica gel, hexane/ethyl acetate 10:3, Rf = 0.65), FTIR (KBr,
cm−1): 837, 1252 (SiMe3), 1510, 1629 (Ar), 1706 (CO), 2858, 2928
1
(CH), 3419 (NH); H NMR: δ −0.08 (s, 9 H, SiMe3), 0.19 (s, 9 H,
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(4-chlorophenylamino)
methyl]cycloheptanone (3k):Yellow solid; yield 75% (anti/syn 80:20),
(silica gel, hexane/ethyl acetate, 10:2, Rf = 0.83 ); m.p. 107–109 °C;
FTIR (KBr, cm−1): 839, 1254 (SiMe3), 1645, 1696, (Ar), 2856, 2926
(CH), 1736 (CO), 3444 (NH); 1H NMR: δ −0.11 (s, 9 H, SiMe3), 0.16
(s, 9 H, SiMe3), 1.70–2.50 (m, 10 H, CH2), 2.81–2.91 (m, 1 H, COCH,
anti+syn), 4.41(d, J = 6.8 Hz, 0.8 H, CHN, anti), 4.47 (s, 0.2 H, CHN,
syn), 5.02 (s, 1 H, NH), 6.40 (d, J = 8.8 Hz, 2 H, Ar), 6.95 (d, J =
8.4 Hz, 2 H, Ar), 7.08 (d, J = 7.8 Hz, 2 H, Ar), 7.19 (d, J = 7.6 Hz,
2 H, Ar), 7.68 (s, 1 H, HC=, syn+anti); 13C NMR: δ −0.56, 0.9 (SiMe3),
23.29–59.20 (CH2), 113.69–153.20 (Ar), 214.7 (CO). Anal. Calcd for
C28H40ClNOSi2: C, 67.50; H, 8.09; N, 2.81. Found: C, 67.83; H, 8.33;
N, 2.93%.
2-[4-(2,2-Bis(trimethylsilyl)ethenyl)benzylidene]cycloheptanone
(4):Yellow viscous oil. (silica gel, hexane/ethyl acetate 10:3, Rf = 0.8);
FTIR (KBr, cm−1): 838, 1252 (SiCH3), 1490, 1693 (Ar), 1703 (CO),
2857, 2928, 3052 (CH), 1H NMR (400 MHz, CDCl3, ppm): −0.03 (s,
9 H, SiMe3), 0.17 (s, 9 H, SiMe3), 1.77–1.94 (m, 4 H, CH2), 2.54 (t,
J = 6.4 Hz, 2 H, CH2 ), 2.85 (t, J = 5.6 Hz, 2 H, CH2CO), 7.19 (d,
J = 7.6 Hz, 2 H, Ar), 7.34 ( d, J =7.6 Hz, 2 H, Ar), 7.5 (s, 1 H, HC=),
7.71 (s, 1 H, HC=). 13C NMR: δ −0.5, 0.9 (SiCH3), 21.7–57.7 (CH2),
112.5–156.3 (Ar and Cvinyl), 211.9 (CO).
SiMe3), 1.61–2.49 (m, 8 H, CH2), 2.70–2.80 (m, 1 H, COCH,
anti+syn), 4.56 (d, J = 7.6 Hz, 0.75 H, CHN, anti), 4.7 (d, J = 3.7 Hz,
0.25 H, CHN, syn), 6.44–6.49 (m, 2 H, Ar), 6.72–6.78 (m, 2 H, Ar),
7.13 (d, J = 7.6 Hz, 2 H, Ar), 7.27 (d, J = 7.2 Hz, 2 H, Ar), 7.72 (s,
1 H, HC=, syn+anti); 13C NMR: δ −0.57, 0.8 (SiMe3), 22.5–57.0
(CH2), 57.6 (CN), 114.0–156.0 (Ar), 210.4, 211.7 (CO). Anal. Calcd
for C27H38FNOSi2: C, 69.33; H, 8.19; N, 2.99. Found: C, 69.37; H,
8.40; N, 2.58%.
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(4-nitrophenylamino)
methyl]cyclohexanone (3f): Yellow solid; yield 89% (anti/syn 61:39)
(silica gel, hexane/ethyl acetate 10:4, Rf = 0.85), m.p. 157–160 °C;
FTIR (KBr, cm−1): 838, 1254 (SiMe3), 1531, 1599 (Ar), 1708 (CO),
2859, 2932 (CH), 3391 (NH); 1H NMR: δ −0.11 (s, 9 H, SiMe3), 0.16
(s, 9 H, SiMe3), 1.59–2.00 (m, 6 H, CH2), 2.32–2.43 (m, 2 H, CH2CO),
2.83–2.85 (m, 1 H, COCH, anti+syn), 4.66 (t, 0.61 H, CHN, anti),
4.81 (t, 0.39 H, CHN,syn), [5.60 (d, J = 6.0 Hz, syn) and 5.63 (d,
J = 6.4 Hz, anti), 1 H, NH], 6.46 (d, J = 8.8 Hz, 2 H, Ar), 7.12–7.14
(m, 2 H,Ar), 7.23 (d, J = 6.9 Hz, 2 H,Ar), 7.69 (s, 1 H, HC=, anti+syn),
7.96 (d, J = 9.2 Hz, 2 H, Ar); 13C NMR: δ −0.0, 0.8 (SiMe3), 16.9–55.9
(CH2), 56.9 (CN), 111.2–153.0 (Ar), 210.2, 211.3 (CO);Anal. Calcd
for C27H38N2O3Si2: C, 65.54; H, 7.74; N, 5.66. Found: C, 65.83; H,
7.93; N, 5.39%.
4-[4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl]-4-(phenylamino)butan-
2-one (5a): Brown viscous oil; yield 80% (silica gel, hexane/ethyl
acetate, 10:2, Rf = 0.5 ); FTIR (KBr, cm−1): 839, 1254 (SiMe3), 1425,
1460, 1612 (Ar), 1709 (CO), 2856, 2925 (CH), 3448 (NH), 1H NMR:
δ −0.08 (s, 9 H, SiMe3), 0.18 (s, 9 H, SiMe3), 2.10 (s, 3 H, CH3CO),
2.92 (d, J = 6.4 Hz, 2 H, CH2), 4.82 (t, J = 6.4 Hz, 1 H, CHN), 6.52 (d,
2-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl)(p-tolylamino)methyl]
cyclohexanone (3g): Yellow solid; yield 85% (anti/syn 80:20), (silica
gel, hexane/ethyl acetate 10:2, Rf = 0.6), m.p. 109–111˚C. FTIR (KBr,
cm−1): 840, 1250 (SiMe3), 1556, 1618 (Ar), 1707 (CO), 2860, 2933
(CH), 3408 (NH); H NMR: δ 0.05 (s, 9 H, SiMe3), 0.32 (s, 9 H,
SiMe3), 1.69–2.62 (m, 8 H, CH2), 2.30 (s, 3 H, Me), 2.83–2.93 (m,
1

578 JOURNAL OF CHEMICAL RESEARCH 2012
J = 7.6 Hz, 2 H, Ar), 6.66–7.15 (m, 5H, Ar), 7.27 (d, J = 8.0 Hz, 2 H,
Ar), 7.70 (s, 1 H, HC=); 13C NMR: δ −0.5, 0.9 (SiMe3), 21.7–53.4
(CH2COCH3), 112.9–153.3 (Ar), 206.2 (CO). Anal. Calcd for
C24H35NOSi2: C, 70.36; H, 8.61; N, 3.42. Found: C, 70.65; H, 8.95; N,
3.16%.
Received 11 June 2012; accepted 3 July 2012
Paper 1201367 doi: 10.3184/174751912X13450464806822
Published online: 28 September 2012
References
4-[4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl]-4-(4-chlorophenylamino)
butan-2-one (5b): Pale yellow solid; yield 75% (silica gel, hexane/
ethyl acetate, 10:2, Rf = 0.56); m.p. 107–110˚C FTIR (KBr, cm−1):
839, 1254 (SiMe3), 1501, 1604, 1647 (Ar), 1710 (CO), 2656, 2926
1
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(CH), 3410 (NH); H NMR: δ −0.04 (s, 9 H, SiMe3), 0.22 (s, 9 H,
SiMe3), 2.13 (s, 3 H, CH3CO), 2.95 (d, J = 6.4 Hz, 2 H, CH2CO), 4.59
(s, 1 H, NH), 4.79 (t, J = 6.4 Hz, 1 H, CHN), 6.47 (d, J = 8.8 Hz, 2 H,
Ar), 7.04 (d, J = 8.8 Hz, 2 H, Ar), 7.16 (d, J = 8.0 Hz, 2 H, Ar), 7.28
(d, J = 8.0 Hz, 2 H, Ar), 7.74 (s, 1 H, HC=); 13C NMR: δ −0.5, 0.9
(SiMe3), 21.7–53.5 (CH2CO), 114.0–153.2 (Ar), 206.1 (CO). Anal.
Calcd for C24H34ClNOSi2: C, 64.90; H, 7.72; N, 3.15. Found: C, 65.12;
H, 7.94; N, 2.86%.
4
5
6
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K.D. Safa, K. Ghorbanpour, A. Hassanpour and S. Tofangdarzade,
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3-[(4-(2,2-Bis(trimethylsilyl)ethenyl)phenyl]-3-(4-chlorophenyl-
amino)-1-phenylpropan-1-one (5c): Yellow solid; yield 70% (silica
gel, hexane/ethyl acetate, 10:2, Rf = 0.92); m.p. 105–107 °C FTIR
(KBr, cm−1): 836, 1255 (SiMe3), 1670 (CO), 2859, 2926, 3097 (CH),
8
9
A. Shahrisa and M. Zirak, J. Heterocycl Chem., 2010, 47, 594.
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1
3391 (NH); H NMR: δ −0.11 (s, 9 H, SiMe3), 0.16 (s, 9 H, SiMe3),
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17 B. Eftekhari-Sis, A. Abdollahifar, M.M. Hashemi and Zirak, M., Eur. J.
Org. Chem., 2006, 22, 5152.
3.37–3.51 [2×dd: 3.40 (dd, J = 8.0 Hz, J = 16.0 Hz 1 H, CH2), 3.48
(dd, J = 4.8 Hz, J = 16.0 Hz, 1 H, CH2), CH2 Diastereotopic protons],
4.64 (s, br, 1 H, NH), 4.90–4.93 (m, 1 H, CHN), 6.44 (d, J = 8.8 Hz,
2H, Ar), 6.99-758 (m, 9 H, Ar), 7.69 (s, 1 H, HC=), 7.69 (d, J = 7.2 Hz,
2 H, Ar), 13C NMR: δ −0.51, 0.93 (SiMe3), 28.7–54.0 (CH2), 114.1–
153.2 (Ar), 197.3 (CO). Anal. Calcd for C29H36ClNOSi2: C, 68.81; H,
7.17; N, 2.77. Found: C, 68.55; H, 7.42; N, 2.40%.
18 R. Ghosh, S. Maiti, A. Chakraborty, S. Chakraborty and A.K. Mukherjee,
We thank Dr J.D. Smith for his helpful comments.
Tettrahedron, 2006, 62, 4059.

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