Oxidation of aliphatic α,β-unsaturated aldimines to amides specifically by oxone with AlCl3

Article abstract of DOI:10.1080/00397910802138892

α,β-Unsaturated aldimines were specifically oxidized to amides with Oxone in the presence of AlCl3 as a Lewis acid in CH2Cl2. No migration of aryl group occurred in the rearrangement reaction. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910802138892

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Oxidation of Aliphatic α,β-
Unsaturated Aldimines to
Amides Specifically by Oxone
with AlCl3
Zhou Lu a , Lijun Peng a , Wentao Wu a & Longmin
Wu a
a State Key Laboratory of Applied Organic
Chemistry , Lanzhou University , Lanzhou, China
Published online: 11 Jul 2008.
To cite this article: Zhou Lu , Lijun Peng , Wentao Wu & Longmin Wu (2008) Oxidation
of Aliphatic α,β-Unsaturated Aldimines to Amides Specifically by Oxone with AlCl3
, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 38:14, 2357-2366, DOI: 10.1080/00397910802138892
To link to this article: http://dx.doi.org/10.1080/00397910802138892
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Synthetic Communications1, 38: 2357–2366, 2008
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910802138892
Oxidation of Aliphatic a,b-Unsaturated
Aldimines to Amides Specifically by Oxone
with AlCl3
Zhou Lu, Lijun Peng, Wentao Wu, and Longmin Wu
State Key Laboratory of Applied Organic Chemistry, Lanzhou University,
Lanzhou, China
Abstract: a,b-Unsaturated aldimines were specifically oxidized to amides with
Oxone in the presence of AlCl3 as a Lewis acid in CH2Cl2. No migration of aryl
group occurred in the rearrangement reaction.
Keywords: Aldimine; amide; Oxidation; Oxone; rearrangement
a,b-Unsaturated amides are an important kind of building block in
organic synthesis.[1] They have been used particularly for preparing
natural products.[2] Their amide groups are available for further functio-
nalizations and can activate the double bonds for additions and other
reactions. In addition, a,b-unsaturated amides exhibit both biological[3]
and insecticide activities.[4] Therefore, the preparation of a,b-unsaturated
amides has attracted more attention from chemists and has been achieved
via various approaches.[4c,5–10] On reviewing the previous methods, we
found that the remaining common problems were either unavailable
starting materials or multi step preparations.
Oxone (2KHSO5 . KHSO4 . K2SO4) is a powerful, environmentally
friendly oxidant.[11] It has been widely used in organic preparation. It
oxidized alcohols to aldehydes and ketones[12] and broke double bonds
to give acids.[13] Acetoxylation and etherification of arenes and alkanes
were achieved with Oxone in the presence of Pd(OAc)2 used as a
Received July 13, 2007
Address Correspondence to Longmin Wu, State Key Laboratory of Applied
Organic Chemistry, Lanzhou University, Lanzhou 730000, China. E-mail:
nlaoc@lzu.edu.cn
2357

2358
Z. Lu et al.
Scheme 1. Oxidation of a, b-unsaturated aldimines.
catalyst.[14] An alkyne and an amine were converted to an amide by
Oxone.[15] It has been singularly noteworthy that Oxone was particularly
favorable for the epoxidation of olefins[11a,16] and for the formation of an
oxaziridine intermediate.[17] Our interest in the latter promoted us to
carry out this investigation in hope of that an epoxidation might occur
=
on a CꢀN double bond adjacent to a C C double bond with Oxone
and in turn a complex of the oxygen of an oxazirindine with AlCl3 might
form. The resulting complex is expected to undergo a hydride migration
to the electron-deficient nitrogen atom as in the Beckmann rearrange-
ment and then a ring opening to give an amide with no migration of aryl
=
group and no change in the a,b-double C C bonds.
We started with an (E)-a, b-unsaturated aldimine 1 (Scheme 1),
which was easily prepared by the reaction of an (E)-a, b-unsaturated
aldehyde with an amine at toluene reflux temperature and by removing
water through a water segregator.[18] Treatment of 1 with Oxone in the
presence of AlCl3 as a Lewis acid in CH2Cl2 at room temperature
afforded, after hydrolysis, a single rearranged amide 2 (Scheme 1 and
1
Table 1). Products were characterized by IR, MS, H and 13C NMR. It
is particularly worthy pointing out that simple imines without a,b-
unsaturated bonds such as 1r (Table 1) were unfavorable for the reaction.
It appears that conjugated double bonds may play a key role in the
reaction. In An’s work,[19] simple imines were alternatively oxidized to
two amides by m-CPBA and BF3 . OEt2. Their reaction selectivity closely
depended on the electron density on the nitrogen atom as well as the
difference in the migratory aptitude of groups to an electron-deficient
nitrogen atom when the reaction proceeded via an oxaziridine inter-
mediate. Our experiments showed that the two a,b-unsaturated amides
employed in An’s work[19a] were not obtained under the present con-
ditions (Scheme 2), whereas all substrates employed in the present work
were not converted to amides using m-CPBA and BF3 . OEt2. Further-
more, no migration of the aryl group occurred in the present cases.
As such, these two approaches may occur via different mechanisms.
The existence of a,b-unsaturated bonds largely disfavored the group
migration in an oxaziridine intermediate.

Oxidation of a,b-Unsaturated Aldimines
2359
Table 1. Oxidation of a,b-unsaturated aldimines with Oxone and AlCl3 in
CH2Cl2
Substrate
R1
R2
Yield of 2(%)a Aldehyde (%)c
1a
1b
1c
1d
1e
1f
Ph
Ph
Ph
Ph
CH2Ph
CH(CH3)Ph
C(CH3)3
78
75
70
81
84
82
78
87
68
65
60
72
50
55
66
0
12
15
17
10
8
10
13
5
20
20
20
17
21
23
20
95
0
b
CH(CH2)5
(p)-MeO-Ph
(p)-MeO-Ph
(p)-MeO-Ph
(p)-MeO-Ph
(p)-Cl-Ph
(p)-Cl-Ph
(p)-Cl-Ph
(p)-Cl-Ph
(p)-NO2-Ph
(p)-NO2-Ph
Ph
CH2Ph
CH(CH3)Ph
C(CH3)3
1g
1h
1i
b
CH(CH2)5
CH2Ph
CH(CH3)Ph
C(CH3)3
1j
1k
1l
b
CH(CH2)5
C(CH3)3
1m
1n
1o
1p
1q
1r
b
CH(CH2)5
CH2(CH2)16CH3
Ph
CH(COOEt)CH2Ph
Ph
Ph
0
0
92
aYields refer to isolated products.
bCyclohexyl.
From Table 1, it can be observed that both substituents of R1 and R2
exert significant effects on the reaction. In general, an electron-donating
substituent at the para-position of a benzene ring in R1 is favorable for
the reaction, whereas an electron-withdrawing group leads to a lower yield
of product. R2 with a large block or an electron-withdrawing character did
not favor the reaction. These observations are rationalized by a proposed
Scheme 2. Oxidation of a, b-unsaturated aldimines under different conditions.

2360
Z. Lu et al.
Scheme 3. Mechanism for the oxidation of a, b-unsaturated aldimines with
Oxone and AlCl3.
mechanism for this reaction depicted in Scheme 3. An aldimine is firstly
oxidized by Oxone to an oxazirindine 3, whose oxygen is active toward
AlCl3 and forms its own 1:1 complex 4 as it is produced. So, for every mol-
ecule of amine formed in the reaction, one molecule of AlCl3 is used up in
complex formation. A stoichiometric amount of AlCl3 is required in this
reaction. Complex 4 undergoes an intramolecular hydride migration to
the elecron-deficient nitrogen atom and a ring opening to give 5. At the
end of the reaction, addition of water destroys the complex and generates
the free amide 2. Obviously, a bulky or an electron-withdrawing group
(R2) upon the nitrogen atom will slow the formation of oxazirindine by
Oxone and inhibit the oxygen of oxazirindine approaching to AlCl3 owing
to a steric or an electronic effect. An electron-withdrawing group linked to
the nitrogen atom will lead to a decrease in the electron density on the oxy-
gen atom of oxazirindine. Otherwise, the migration of the aryl group linked
at b-C of the a,b-double bond will be thermodynamically unfavorable.
The effect of Lewis acids on the reaction was examined using 1a as a
substrate (Table 2). AlCl3 was found to be the most favorable Lewis acid,
whereas ZrCl4, Mg(ClO4)2 and BF3 . OEt2 did not exert any affect on the
reaction.
Table 2. Effect of Lewis acids on the yield of 1a in CH2Cl2
Entry
Lewis acid
Yield of 2a(%)
1
2
3
4
5
6
AlCl3
FeCl3
ZnCl4
ZrCl4
Mg(ClO4)2
BF3 . OEt2
78
55
30
0a
0b
0
a2-Benzyl-3-styryl-1,2-oxaziridine was isolated in 66% yield.
b2-Benzyl-3-styryl-1,2-oxaziridine was isolated in 74% yield.

Oxidation of a,b-Unsaturated Aldimines
2361
In summary, an approach for preparing a,b-unsaturated amines
developed in the present work provides an efficient method for the
conversion of aldimines to amides by oxone and AlCl3. No migration
of aryl group occurred in the rearrangement reaction.
EXPERIMENTAL
A representative procedure: To a solution containing 0.77 mmol of 1a in
15mL of anhydrous CH2Cl2, 1.54mmol of oxone, 2.69 mmol of NaHCO3,
and 0.92 mmol of anhydrous AlCl3 were added. The mixture was stirred
for 8–12 h at ambient temperature, then quenched with water (20 mL),
and extracted with CH2Cl2 (3 ꢁ 15 mL). The organic layer was dried over
anhydrous MgSO4, filtered, concentrated under vacuum, and purified by
flash-column chromatography on silica gel (petroleum ether–acetic ether,
5:1). Products were characterized by IR, 1H and 13C NMR, and MS spec-
1
troscopy [IR: Nicolet Nexus 670 FT-IR; NMR: H: 300=400 MHz, 13C:
75=100 MHz, Varian Mercury 300=400 (TMS); MS: HP-5988, EI (70 eV)].
Characterization Data for Products
Compound 2a[20a]: mp 106–108 ꢂC. IR (KBr): nmax cmꢀ1 3263, 1652,
1
=
1615. H NMR(300 MHz, CDCl3): d 7.67 (d, J ¼ 15.3 Hz, 1H, CH CH),
7.47 (m, 2H, arom), 7.32 (m, 8H, arom), 6.44 (d, J ¼ 15.3 Hz, 1H,
CH CH), 6.21 (s, 1H, NH), 4.54 (d, J ¼ 4.8 Hz, 2H, CH2). 13C NMR
=
(75 MHz, CDCl3): d 165.8 (1C), 141.3 (1C), 138.2 (1C), 134.7 (1C),
129.6 (2C), 128.7 (2C), 128.6 (1C), 127.9 (2C), 127.8 (1C), 127.5 (2C),
120.4 (1C), 43.8 (1C). MS (EI) m=z (%): 237 (Mþ , 42), 160 (5), 131
(93), 106 (57), 103 (76), 91 (45), 77 (100).
Compound 2b[20b]
:
1H NMR (400 MHz, CDCl3) d 7.61 (d,
=
J ¼ 15.6 Hz, 1H, CH CH), 7.43 (m, 2H, arom), 7.19 (m, 8H, arom),
=
6.44 (d, J ¼ 15.6 Hz, 1H, CH CH), 6.29 (s, 1H, NH), 5.25 (q, J ¼ 7.2 Hz,
1H, CH), 1.55 (d, J ¼ 7.2 Hz, 3H, CH3). 13C NMR(100 MHz, CDCl3)
d 165.0 (1C), 143.1 (1C), 141.1 (1C), 134.7 (1C), 129.5 (2C), 128.7
(2C), 128.6 (1C), 127.7 (2C), 127.2 (1C), 126.2 (2C), 120.6 (1C), 48.8
(1C), 21.6 (1C). MS (EI) m=z (%): 251 (Mþ, 5), 146 (6), 131 (100),
120 (1), 105 (41), 103 (54), 77 (75).
Compound 2c[20c]
:
1H NMR (300 MHz, CDCl3) d 7.56 (d,
=
J ¼ 15.3 Hz, 1H, CH CH), 7.47 (m, 2H, arom), 7.30 (m, 3H, arom),
=
6.38 (d, J ¼ 15.3 Hz, 1H, CH CH), 5.79 (s, 1H, NH), 1.42 (s, 9H,
CH3). 13C NMR (75 MHz, CDCl3) d 165.2 (1C), 140.0 (1C), 134.8 (1C),
129.3 (2C), 128.6 (1C), 127.5 (2C), 122.0 (1C), 51.4 (1C), 28.7 (3C). MS
(EI) m=z (%): 203 (Mþ , 14), 188 (8), 146 (39), 131 (100), 103 (48), 77 (43).

2362
Z. Lu et al.
Compound 2d[20d]
:
1H NMR (400 MHz, CDCl3) d 7.60 (d,
=
J ¼ 15.6 Hz, 1H, CH CH), 7.45 (m, 2H, arom), 7.33 (m, 3H, arom),
=
6.43 (d, J ¼ 15.6 Hz, 1H, CH CH), 5.94 (s, 1H, NH), 3.90 (m, 1H,
CH), 1.97 (m, 2H, CH2), 1.70 (m, 2H, CH2), 1.24 (m, 2H, CH2), 1.15
(m, 4H, CH2). 13C NMR (100 MHz, CDCl3) d 164.9 (1C), 140.4 (1C),
134.8 (1C), 129.4 (2C), 128.6 (1C), 127.6 (2C), 121.2 (1C), 48.3 (1C),
33.1 (2C), 25.4 (1C), 24.8 (2C). MS (EI) m=z (%): 229 (Mþ , 18), 146
(42), 131 (100), 103 (47), 98 (24), 83 (15), 77 (37).
Compound 2e[20e]: 1H NMR (300 MHz, CDCl3) d 7.61 (d, J ¼ 15.3 Hz,
=
1H, CH CH), 7.41 (m, 2H, arom), 7.31 (m, 5H, arom), 6.84 (m, 2H, arom),
=
6.30 (d, J ¼ 15.3 Hz, 1H, CH CH), 6.15 (s, 1H, NH), 4.53 (s, 2H, CH2),
3.81 (s, 3H, CH3). 13C NMR(75 MHz, CDCl3) d 166.1 (1C), 160.8 (1C),
140.8 (1C), 138.3 (1C), 129.3 (1C), 128.6 (2C), 128.4 (2C), 127.8 (2C),
127.4 (1C), 118.0 (1C), 114.2 (2C), 55.3 (1C), 43.7 (1C). MS-EI m=z (%)
267 (Mþ , 36), 161 (100), 134 (52), 106 (31), 91 (87), 77 (39).
Compound 2f[20f]: 1H NMR (300MHz, CDCl3) d 7.59 (d, J ¼ 15.3 Hz,
=
1H, CH CH), 7.28 (m, 7H, arom), 6.83 (t, J ¼ 7.2 Hz, 2H, arom), 6.39
=
(d,J ¼ 15.3 Hz, 1H, CH CH), 6.72 (s, 1H, NH), 5.26 (q, J ¼ 7.2 Hz, 1H,
CH), 3.79 (s, 3H, CH3), 1.55 (d, J ¼ 7.2 Hz, 3H, CH3). 13C NMR
(75 MHz, CDCl3) d 165.4 (1C), 160.5 (1C), 143.2 (1C), 140.4 (1C), 129.2
(1C), 128.4 (2C), 127.4 (2C), 127.1 (2C), 126.1 (1C), 118.4 (1C), 114.0 (2C),
55.1 (1C), 48.7 (1C), 21.7 (1C). MS (EI) m=z (%): 281 (Mþ , 72), 264 (3),
188 (5), 176 (10), 160 (100), 161 (21), 121 (12), 120 (32), 105 (46), 77 (64).
Compound 2g[20g]: 1H NMR (300 MHz, CDCl3) d 7.51 (d, J ¼ 15.9 Hz,
=
1H, CH CH), 7.40 (dd, 2H, J ¼ 1.5Hz, J ¼ 9 Hz, arom), 6.85 (dd, 2H,
=
J ¼ 1.5 Hz, J ¼ 9 Hz, arom), 6.22 (d, J ¼ 15.9 Hz, 1H, CH CH), 5.56 (s,
1H, NH), 3.80 (s, 3H, CH3), 1.41 (s, 9H, CH3). 13C NMR (75MHz, CDCl3)
d 165.5 (1C), 159.7 (1C), 141.1 (1C), 128.3 (1C), 127.6 (2C), 119.5 (1C),
114.1 (2C), 55.2 (1C), 51.3 (1C), 28.8 (3C). MS (EI) m=z (%): 233 (Mþ ,
27), 176 (46), 161 (100), 133 (11), 77ꢂ(12).
Compound 2h[20h]: mp 158–160 C. IR (KBr): nmax cmꢀ1 3275, 3068,
1652, 917. 1H NMR (300 MHz, CDCl3): d 7.55 (d, J ¼ 15.3 Hz, 1H,
=
CH CH), 7.42 (d, J ¼ 9 Hz, 2H, arom), 6.85 (d, J ¼ 9 Hz, 2H, arom),
=
6.27 (d, J ¼ 15.3 Hz, 1H, CH CH), 5.72 (s, 1H, NH), 3.89 (m, 1H,
CH), 3.80 (s, 3H, CH3), 1.97 (m, 2H, CH2), 1.63 (m, 3H, CH2), 1.36
(m, 2H, CH2), 1.15 (m, 3H, CH2). 13C NMR (75 MHz, CDCl3): d
165.2 (1C), 160.6 (1C), 140.2 (1C), 129.1 (1C), 127.5 (2C), 118.7 (1C),
114.1 (2C), 55.2 (1C), 48.2 (1C), 33.2 (2C), 25.4 (1C), 24.8 (2C). MS
(EI) m=z (%): 259 (Mþ, 2), 176 (12), 161 (100), 133 (23), 98 (17), 83
(15), 77 (34).
Compound 2i[20i]
: d 7.60 (d,
1H NMR (300 MHz, CDCl3)
=
J ¼ 15.9 Hz, 1H, CH CH), 7.39 (m, 4H, arom), 7.18 (m, 5H, arom),
=
6.39 (d, J ¼ 15.9 Hz, 1H, CH CH), 6.14 (s, 1H, NH), 4.54 (d, J ¼ 4.8 Hz,

Oxidation of a,b-Unsaturated Aldimines
2363
Hz, 2H, CH2). 13C NMR (75 MHz, CDCl3) d 165.5 (1C), 140.0 (1C),
138.0 (1C), 135.5 (1C), 133.1 (1C), 129.0 (2C), 128.9 (2C), 128.7 (2C),
127.8 (2C), 127.6 (1C), 120.9 (1C), 43.8 (1C). MS (EI) m=z (%): 271
(Mþ , 33), 273 (M þ 2, 12), 165 (10), 167 (3), 137 (33), 139 (12), 111
(14), 113 (5), 106 (100), 91 (81), 77 (36).
Compound 2j[20f]
: d 7.56 (d,
1H NMR (300 MHz, CDCl3)
=
J ¼ 15.3 Hz, 1H, CH CH), 7.33 (m, 9H, arom), 6.40 (d, J ¼ 15.3 Hz,
=
1H, CH CH), 6.21 (s, 1H, NH), 5.25 (q, J ¼ 7.2 Hz, 1H, CH), 1.54 (d,
J ¼ 7.2 Hz, 3H, CH3). 13C NMR (75 MHz, CDCl3) d 164.6 (1C), 142.9
(1C), 139.8 (1C), 135.4 (1C), 133.2 (1C), 128.9 (2C), 128.8 (2C), 128.5
(2C), 127.4 (2C), 126.2 (1C), 121.2 (1C), 48.9 (1C), 21.6 (1C). MS (EI)
m=z (%): 285 (Mþ , 27), 287 (M þ 2, 9), 180 (5), 182 (2), 165 (85), 167
(27), 120 (100), 105 (53), 77 (43).
Compound 2k[20h]
:
1H NMR (300MHz, CDCl3) d 7.49 (d,
=
J ¼ 15.9 Hz, 1H, CH CH), 7.38 (dd, 2H, J ¼ 4.8 Hz, J ¼ 8.7 Hz, arom),
7.27 (dd, 2H, J ¼ 4.8 Hz, J ¼ 8.7 Hz, arom), 6.32 (d, J ¼ 15.9 Hz, 1H,
CH CH), 5.66 (s, 1H, NH), 1.41 (s, 9H, CH3). 13C NMR (75 MHz,
=
CDCl3) d 164.8 (1C), 138.7 (1C), 135.1 (1C), 133.4 (1C), 129.3 (2C),
128.8 (2C), 122.5 (1C), 51.5 (1C), 29.6 (3C). MS (EI) m=z (%): 237
(Mþ , 19), 239 (M þ 2, 6), 222 (9), 224 (3), 180 (10), 182 (3), 165 (11),
167 (3), 137 (24), 139 (9), 57 (42).
Compound 2l[20j]: mp 198–200ꢂC. IR (KBr) nmax cmꢀ1 3280, 3077,
1657, 972. 1H NMR (300 MHz, CDCl3) d 7.54 (d, J ¼ 15.3 Hz, 1H,
=
=
CH CH), 7.31 (m, 4H, arom), 6.37 (d, J ¼ 15.3 Hz, 1H, CH CH),
6.78 (s, 1H, NH), 3.89 (m, 1H, CH), 1.10–1.87 (m, 10H, CH2). 13C
NMR (75 MHz, CDCl3) d 164.6 (1C), 139.2 (1C), 135.2 (1C), 133.3
(1C), 128.9 (2C), 128.8 (2C), 122.6 (1C), 48.3 (1C), 33.1 (2C), 25.4
(1C), 24.8 (2C). MS (EI) m=z (%): 263 (Mþ , 3), 265 (M þ 2, 1), 180
(10), 182 (4), 165 (77), 167 (27), 137 (28), 139 (11), 125 (9), 111 (23),
113 (6), 98 (28), 83 (36).
Compound 2m[20k]
:
1H NMR (400 MHz, CDCl3) d 8.27 (d, 2H,
=
J ¼ 9 Hz, arom), 7.63 (d, J ¼ 15.6 Hz, 1H, CH CH), 7.59 (d, 2H,
=
J ¼ 9 Hz, arom), 6.46 (d, J ¼ 15.6 Hz, 1H, CH CH), 5.62 (s, 1H, NH),
1.42 (s, 9H, CH3). 13C NMR (100 MHz, CDCl3) d 164.1 (1C), 147.4
(1C), 144.0 (1C), 141.3 (1C), 128.2 (2C), 124.2 (C), 122.1 (1C), 48.3
(1C), 28.7 (3C). MS (EI) m=z (%): 248 (Mþ , 3), 233 (2), 203 (2), 176
(8), 97 (4), 69 (7), 57 (32).
Compound 2n[20j]: mp 208–210 ꢂC. IR (KBr): nmax cmꢀ1 3280, 3077,
1
1657, 1513, 1341, 972, 848. H NMR (300 MHz, CDCl3): d 8.21 (d, 2H,
=
J ¼ 8.4 Hz, arom), 7.64 (d, J ¼ 15.9 Hz, 1H, CH CH), 7.62 (d, 2H,
=
J ¼ 8.4 Hz, arom), 6.49 (d, J ¼ 15.9 Hz, 1H, CH CH), 5.62 (s, 1H,
NH), 3.91 (m, 1H, CH), 1.98 (m, 2H, CH2), 1.69 (m, 3H, CH2), 1.40
(m, 2H, CH2), 1.20 (m, 3H, CH2). 13C NMR(75 MHz, CDCl3): d 163.7

2364
Z. Lu et al.
(1C), 147.9 (1C), 141.2 (1C), 137.9 (1C), 128.2 (2C), 125.3 (2C), 122.1
(1C), 48.5 (1C), 33.1 (2C), 25.4 (1C), 24.7 (2C). MS (EI) m=z (%): 274
(Mþ, 4), 193 (11), 176 (9), 130 (10), 102 (70), 98 (28), 83 (3).
Compound 2o: mp 104–106ꢂC. IR (KBr): nmax cmꢀ1 291, 3086, 1654,
1
=
970. H NMR (300 MHz, CDCl3): d 7.61 (d, J ¼ 15.3 Hz, 1H, CH CH),
7.47 (t, J ¼ 3.6 Hz, 2H, arom), 7.33 (t, J ¼ 3.6 Hz, 3H, arom), 6.39 (d,
=
J ¼ 15.3 Hz, 1H, CH CH), 5.73 (s, 1H, NH), 3.37 (q, J ¼ 6.3 Hz, 2H,
CH2), 1.56 (m, 2H, CH2), 1.29 (m, 30H, CH2), 0.87 (t, J ¼ 6.3 Hz, 3H,
CH3). 13C NMR (75 MHz, CDCl3): d 165.8 (1C), 140.7 (1C), 134.8
(1C), 129.5 (2C), 128.7 (1C), 127.7 (2C), 120.7 (1C), 39.7 (1C), 31.8
(1C), 30.9 (11C), 29.6 (1C), 29.3 (1C), 26.9 (1C), 22.6 (1C), 14.2 (1C).
MS (EI) m=z (%): 399 (Mþ , 2), 268 (1), 146 (15), 131 (100), 103 (29),
77 (17). HRMS m=z: calcd. for C27H45NO: 399.3494; found: 399.3490.
ACKNOWLEDGMENT
Project 20572040 was supported by the National Natural Science Foun-
dation of China.
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