Accelerated amination of baylis-hillman acetates under ultrasound irradiation

Article abstract of DOI:10.1080/00397910903219310

The amination of the Baylis-Hillman acetates with primary amines can be dramatically promoted with improved yields and shortened reaction time under ultrasound irradiation. The selected aromatic, heteroaromatic, and aliphatic amines were investigated as t

Full text of DOI:10.1080/00397910903219310

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Accelerated Amination of Baylis–Hillman
Acetates Under Ultrasound Irradiation
Shao-Qin Ge a , Yun-Yu Hua a & Min Xia a
a Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou,
China
Published online: 08 Jun 2010.
To cite this article: Shao-Qin Ge , Yun-Yu Hua & Min Xia (2010) Accelerated Amination of
Baylis–Hillman Acetates Under Ultrasound Irradiation, Synthetic Communications: An International
Journal for Rapid Communication of Synthetic Organic Chemistry, 40:13, 1954-1962, DOI:
10.1080/00397910903219310
To link to this article: http://dx.doi.org/10.1080/00397910903219310
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Synthetic Communications1, 40: 1954–1962, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903219310
ACCELERATED AMINATION OF BAYLIS–HILLMAN
ACETATES UNDER ULTRASOUND IRRADIATION
Shao-Qin Ge, Yun-Yu Hua, and Min Xia
Department of Chemistry, Zhejiang Sci-Tech University,
Hangzhou, China
The amination of the Baylis–Hillman acetates with primary amines can be dramatically
promoted with improved yields and shortened reaction time under ultrasound irradiation.
The selected aromatic, heteroaromatic, and aliphatic amines were investigated as the
effective candidates for the sonochemical transformation.
Keywords: Amination; Baylis–Hillman acetate; primary amine; sonication
The Baylis–Hillman reaction, one of the most significant C–C bond-forming
reactions, affords a highly functionalized product with multiple reactive groups.
Therefore, the Baylis–Hillman adducts and their derivatives are widely utilized as
the useful bricks for building various novel or complicated structures.[1–6] The ami-
nation of Baylis–Hillman acetates is an essential starting step in the preparation of
many cyclic frameworks with N atoms.[7–9] However, it always takes a prolonged
time for such transformation at room temperature, especially in the cases which aro-
matic amines with electron-withdrawing substituents are involved.[10–12] Although
Pathak and coworkers recently reported[13] that their aminations were completed
in 3 h at room temperature for the anilines with either electron-withdrawing or
electron-donating groups in reasonable to good yields, we could not repeat their
results for the anilines with electron-withdrawing groups. We found the exact reac-
tion time for them to afford the products in moderate yields was more than 12 h.
When the aniline with a vicinal electron-withdrawing group was concerned, it was
reported[14] that it took 7 days for the amination with 2-bromoaniline to be
accomplished in moderate (56%) yield. Considering the power of the Baylis–Hillman
derivatives with amino groups in the construction of many significant molecules, we
still desired to develop a more efficient approach to their rapid and convenient
access.
In recent years, ultrasound irradiation has been extensively applied in organic
reactions because of its special sonochemical effect, which is primarily attributed to
hot spots formed during acoustic cavitations.[15–19] In some cases, the thermal effect
Received April 25, 2008.
Address correspondence to Min Xia, Department of Chemistry, Zhejiang Sci-Tech University,
Hangzhou 310018, China. E-mail: xiamin@zstu.edu.cn
1954

AMINATION OF BAYLIS–HILLMAN ACETATES
1955
Scheme 1. Ultrasound-promoted preparation of Baylis–Hillman amines.
resulted from the classical heating, and ultrasound irradiation will lead to entirely
different chemical outcomes. Generally, sonication increases reaction rates and
yields without using harsh conditions. It is also observed that reactions under ultra-
sound irradiation are commonly easier to workup than those in conventional stirring
methods. In continuation of our interest in the ultrasonic effect on organic reac-
tions,[20] herein we describe our example for the observably accelerated amination
of the Baylis–Hillman acetates with primary amines in enhanced yields under ultra-
sound irradiation (Scheme 1).
Since there is a successive SN2–SN2 nucleophilic substitution in the process of
introducing the amino groups at the secondary position of the Baylis–Hillman acet-
ate, an additional base such as 1,4-diazabicyclo[2.2.2]octane (DABCO) should be
used. We adopt a standard reaction condition for the amination of the Baylis–
Hillman acetates: first treat the reaction mixture with DABCO in tetrahydrofuran
(THF)=H2O (1:1) for 15 min, at room temperature, either stirring the mixture or
sonicating it under ultrasound irradiation with the corresponding amine. Both the
acetates derived from aromatic and heteroaroamtic aldehydes and the primary
amines of aromatic, heterocyclic, and aliphatic ones are screened as the candidates
to carry out the nucleophilic substitution, and the results of the reaction in the
two different methods are listed in Table 1. To our best knowledge, there has been
no report in literature about the ultrasonic amination of the Baylis–Hillman acetates.
Table 1 shows that there is an obvious sonochemical effect in the amination of
the Baylis–Hillman acetates under the ultrasound irradiation. Compared with con-
ventional stirring at room temperature, the reaction time is dramatically cut down
and the yield is remarkably increased with ultrasonic amination. More important,
the thermal effect induced by the acoustic cavitations accelerates the reaction with-
out the simultaneously promoting the generation of by-products. Instead, when the
temperature of the reaction under the classical heating condition is elevated, the for-
mation of many side products will make the separation of the desired compounds
tedious, which eventually results in reduced yields. Apparently, the thermal effects
of the classical heating and the ultrasound irradiation lead to somewhat different
chemical outcomes.
We investigated both the electron effect and the space effect of the substituents
on anilines in the amination reaction (entries 1–3, 5, 10, 19, and 20 and entries 4 and
6, respectively). It takes an extended reaction time for the anilines with the
electron-withdrawing groups to afford the products in relatively poor yields. Amina-
tion of 4-nitroaniline, which contains a strong electron-withdrawing group, cannot
be carried out in the DABCO=THF=H2O system, even when the ultrasound
irradiation is executed for a prolonged time (more than 12 h). It is possible that
the nucleophilicity of the anilines is reduced because of the deactivation of the

1956
S.-Q. GE, Y.-Y. HUA, AND M. XIA
Table 1. Amination of Baylis–Hillman acetates under ultrasound irradiation
Classical reaction
Ultrasound reaction
Entry
R1
R2
Product Time (h) Yield (%) Time (h)
Yield (%)
1
2
C6H5
C6H5
C6H5
C6H5
4-CH3OC6H4
4-CH3C6H4
2-CH3C6H4
4-ClC6H4
2,5-(CH3)2C6H3
C6H5CH2
(CH3)2CH
C6H5
3a
3b
3c
3d
3e
3f
8
3
67
83
80
41
55
23
50
75
54
66
49
56
63
81
77
3
84
93
88
55
63
41
70
80
85
87
72
78
81
87
88
1
3
5
1.5
4.5
5
4
C6H5
C6H5
8
5
12
12
5
6
C6H5
C6H5
C6H5
5
7
3g
3h
3i
2
8
6
3
9
2-Pyridiyl
4-ClC6H4
2-ClC6H4
4-FC6H4
4-F3CC6H4
4-BrC6H4
4-CH3C6H4
10
10
12
10
10
3
3.5
3
10
11
12
13
14
15
C6H5
C6H5
3j
3k
3l
5
C6H5
C6H5
4
3m
3n
3o
4
2-H2NC6H4
4-CH3OC6H4
1.5
1
4
16
2,4-Cl2C6H3
3p
6
72
2.5
84
17
18
19
20
2,4-Cl2C6H3
2,4-Cl2C6H3
4-ClC6H4
3-ClC6H4
2-Naphthyl
4-HOC6H4
4-CH3C6H4
3q
3r
3s
3t
12
12
3
31
25
88
75
7
55
33
95
91
5
0.75
2
4-ClC6H4
5
electron-withdrawing groups present in the molecules, leading to the obstruction of
the amination or even the failure of the reaction. Moreover, when there is an aniline
with the substituent at the vicinal position of the amino group, it is envisaged that
the amination involved is largely hindered, as demonstrated in entries 4 and 6. In
addition, when aliphatic primary amines such as benzylamine and isopropylamine
are tested, both of them exhibit the desired nucleophilicity in the amination, provid-
ing the corresponding Baylis–Hillman amines in good yields. Interestingly, it is also
smooth for 4-amino antipyrine (entry 16) as a heterocyclic primary amine to carry
out the substitution of the Baylis–Hillman acetates. Although 2-naphthylamine
(entry 18) is not an active candidate, there is still an observable ultrasonic effect
on its reaction with the corresponding acetate. In the case when double nucleophilic
substituents such as hydroxyl and amino groups are present in the same molecule
(entry 19), the substitution selectively occurs on the amino group.
It seems that the acetates originating from the aromatic aldehydes with differ-
ent substituents have a small influence on the generation of compounds 3 (entries 1
and 10–13 and entries 3 and 20); this may be attributed to the sp3 carbon at the sec-
ondary position of the Baylis–Hillman acetate. Also, the acetate derived from
the heteroaromatic aldehyde such as 2-pyridiylaldehyde was tested to be a potent
candidate for the amination, providing good yields. It is notable in each case of

AMINATION OF BAYLIS–HILLMAN ACETATES
1957
the amination of the different acetates that the ultrasonic irradiation reduces reac-
tion time and enhances yield more than the same reaction using the classical stirring
method.
In conclusion, herein we describe our efficient amination of the Baylis–Hillman
acetates under both conventional stirring and ultrasound irradiation conditions. For
the various primary amines and acetates, the ultrasonic amination generally affords
improved yields and reduced reaction time without the formation of the side
products. The results in our reactions largely expand the substrate scope in the for-
mation of Baylis–Hillman amines than that in previous literature. The ultrasonically
accelerated preparation of the Baylis–Hillman derivatives containing amino groups
is a promising methodology for the convenient approach to significant molecules
with N atoms.
EXPERIMENTAL
All the compounds used are analytical reagents, and some chemicals are
1
further purified by recrystallization or distillation. The H NMR (400 MHz) and
13C NMR (100 MHz) spectra were obtained on a Bruker Avance II DMX400 spec-
trometer using CDCl3 as the solvent. Fourier transform–infrared (FT-IR) spectra
were performed as liquid films or KBr pellets on a Nicolet Avatar spectrophot-
ometer. Ultrasound irradiation was performed in a KQ250E ultrasound cleaner,
whose frequency is 40 KHz and output power is 250 W. The temperature of the water
bath is controlled by addition or removal of water.
General Procedure for the Amination of Baylis–Hillman Acetates
Under Classical Stirring
At room temperature, DABCO (1.5 mmol) was added to the solution of the
Baylis–Hillman acetate 1 (1.0 mmol) in THF=H2O (1:1) (5 mL). The resulting mix-
ture was stirred for 15 min, and then the corresponding amine (1.2 mmol) was added.
The solution was stirred at room temperature for the appropriate time (indicated by
thin-layer chromatography, TLC). When the reaction is over, water was poured into
the solution and EtOAc (2 ꢀ 10 mL) was used to extract the mixture. The combined
organic layers were washed by brine and dried over anhydrous Na2SO4. After the
solvent was removed on a rotating evaporator, the residue was purified using
silica-gel column chromatography with petroleum ether=ethyl acetate as the eluent
to give a yellowish oil or solid.
General Procedure for the Amination of Baylis–Hillman Acetates
Under Ultrasound Irradiation
At room temperature, DABCO (1.5 mmol) was added to the solution of the
Baylis–Hillman acetate 1 (1.0 mmol) in THF=H2O (1:1) (5 mL). The resulting mix-
ture was stirred for 15 min, and then the corresponding amine (1.2 mmol) was added.
The solution was irradiated at 25–30 ꢁC for the appropriate time (indicated by TLC).
The temperature of the water bath was controlled by the addition or removal of
water. When the reaction was over, water was poured into the solution and EtOAc

1958
S.-Q. GE, Y.-Y. HUA, AND M. XIA
(2 ꢀ 10 mL) was used to extract the mixture. The combined organic layers
were washed by brine and dried over anhydrous Na2SO4. After the solvent was
removed on a rotating evaporator, the residue was purified using silica-gel column
chromatography with petroleum ether=ethyl acetate as the eluent to give a yellowish
oil or solid.
Spectral Data
Compound 3a. Yellowish liquid; IR (liquid film): 694, 750, 958, 1069, 1100,
1
1154, 1194, 1286, 1315, 1436, 1452, 1503, 1597, 1717, 2951, 3028, 3052, 3401; H
NMR (400 MHz, CDCl3) d: 3.69 (s, 3H), 3.99 (s, br, 1H, NH), 5.41 (s, 1H), 5.98
(s, 1H), 6.39 (s, 1H), 6.57 (d, 2H, J ¼ 8.0 Hz), 6.72 (t, 1H, J ¼ 7.2 Hz), 7.16 (t, 2H,
J ¼ 7.6 Hz), 7.28 (m, 1H), 7.36 (m, 4H); 13C NMR (100 MHz, CDCl3) d: 51.79,
58.77, 113.27, 117.75, 126.10, 127.40, 127.68, 128.61, 129.01, 139.70, 140.36,
146.41, 166.49.
Compound 3b. Yellowish liquid; IR (liquid film): 701, 776, 819, 1036, 1089,
1117, 1154, 1244, 1439, 1512, 1629, 1717, 2832, 2951, 3030, 3396; 1H NMR
(400 MHz, CDCl3) d: 3.68 (s, 3H), 3.71 (s, 3H), 3.97 (s, br, 1H, NH), 5.33 (s, 1H),
5.97 (s, 1H), 6.38 (s, 1H), 6.53 (d, 2H, J ¼ 8.4 Hz), 6.75 (d, 2H, J ¼ 8.0 Hz), 7.30
(m, 1H), 7.36 (m, 4H); 13C NMR (100 MHz, CDCl3) d: 52.08, 55.69, 59.79,
114.73, 126.31, 126.32, 127.61, 127.84, 128.79, 140.18, 140.78, 140.89, 152.37, 166.83.
Compound 3c. Yellowish liquid; IR (liquid film): 700, 807, 952, 1091, 1126,
1154, 1194, 1285, 1438, 1519, 1617, 1717, 2918, 2950, 3028, 3400; 1H NMR
(400 MHz, CDCl3) d: 2.22 (s, 3H), 3.69 (s, 3H), 3.87 (s, br, 1H, NH), 5.37 (s, 1H),
5.97 (s, 1H), 6.38 (s, 1H), 6.49 (d, 2H, J ¼ 7.6 Hz), 6.96 (d, 2H, J ¼ 8.0 Hz), 7.29
(m, 1H), 7.36 (m, 4H); 13C NMR (100 MHz, CDCl3) d: 18.47, 49.98, 57.28,
111.64, 124.28, 125.20, 125.61, 125.84, 126.80, 127.73, 138.07, 138.74, 142.37, 164.75.
Compound 3d. Yellowish liquid; IR (liquid film): 700, 748, 957, 1052, 1072,
1123, 1155, 1195, 1284, 1442, 1506, 1605, 1719, 2951, 3030, 3429; 1H NMR
(400 MHz, CDCl3) d: 2.14 (s, 3H), 3.71 (s, 3H), 3.80 (s, br, 1H, NH), 5.47 (s, 1H),
5.92 (s, 1H), 6.38 (s, 1H), 6.50 (d, 1H, J ¼ 8.4 Hz), 6.67 (t, 1H, J ¼ 7.6 Hz), 7.07 (t,
2H, J ¼ 7.2 Hz), 7.28 (m, 1H), 7.38 (m, 4H); 13C NMR (100 MHz, CDCl3) d:
17.61, 51.94, 58.83, 111.05, 117.56, 122.21, 126.18, 127.04, 127.52, 127.82, 128.82,
130.11, 140.11, 140.79, 144.59, 166.71.
Compound 3e. Yellowish liquid; IR (liquid film): 502, 701, 764, 816, 960,
1
1007, 1122, 1155, 1287, 1438, 1452, 1496, 1599, 1716, 2951, 3030, 3402; H NMR
(400 MHz, CDCl3) d: 3.61 (s, 3H), 4.21 (s, br, 1H, NH), 5.36 (s, 1H), 5.90 (s, 1H),
6.37 (s, 1H), 6.48 (m, 2H), 7.07 (dd, 2H, J1 ¼ 2.8 Hz, J2 ¼ 8.8 Hz), 7.33 (m, 5H);
13C NMR (100 MHz, CDCl3) d: 52.07, 59.05, 114.58, 122.51, 126.40, 127.52,
128.02, 128.88, 129.05, 139.72, 140.19, 145.23, 166.59.
Compound 3f. Yellowish liquid; IR (liquid film): 700, 748, 797, 913, 1072,
1
1127, 1155, 1285, 1438, 1519, 1582, 1615, 1724, 2921, 2951, 3028, 3434; H NMR
(400 MHz, CDCl3) d: 2.10 (s, 3H), 2.25 (s, 3H), 3.71 (s, 3H), 3.98 (s, br, 1H, NH),
5.46 (s, 1H), 5.94 (s, 1H), 6.31 (s, 1H), 6.39 (s, 1H), 6.49 (d, 1H, J ¼ 7.6 Hz), 6.94

AMINATION OF BAYLIS–HILLMAN ACETATES
1959
(d, 1H, J ¼ 7.6 Hz), 7.30 (m, 1H), 7.37 (m, 4H); 13C NMR (100 MHz, CDCl3)
d: 17.20, 21.60, 51.95, 58.78, 111.72, 118.16, 119.16, 126.15, 127.51, 127.79, 128.81,
129.95, 136.68, 140.04, 140.93, 144.47, 166.76.
Compound 3g. Yellowish liquid; IR (liquid film): 700, 743, 957, 1103, 1149,
1193, 1283, 1438, 1453, 1494, 1626, 1720, 2950, 3028, 3061, 3335; 1H NMR
(400 MHz, CDCl3) d: 1.93 (s, br, 1H, NH), 3.65 (s, 3H), 3.70 (d, 2H, J ¼ 8.0 Hz),
4.71 (s, 1H), 6.02 (s, 1H), 6.37 (s, 1H), 7.23 (t, 2H, J ¼ 7.2 Hz), 7.31 (m, 6H), 7.39
(d, 2H, J ¼ 7.2 Hz); 13C NMR (100 MHz, CDCl3) d: 51.78, 51.88, 62.15, 125.69,
127.06, 127.41, 127.75, 128.23, 128.47, 140.25, 141.53, 141.90, 166.89.
Compound 3h. Colorless liquid; IR (liquid film): 702, 762, 957, 1086, 1144,
1
1195, 1269, 1323, 1364, 1438, 1494, 1627, 1721, 2868, 2962, 3028, 3330; H NMR
(400 MHz, CDCl3) d1.06 (dd, 6H, J1 ¼ 6.4 Hz, J2 ¼ 8.4 Hz), 1.57 (s, br, 1H, NH),
2.72 (m, 1H), 3.67 (s, 3H), 4.80 (s, 1H), 5.92 (s, 1H), 6.32 (s, 1H), 7.22 (t, 1H,
J ¼ 7.2 Hz), 7.33 (m, 4H); 13C NMR (100 MHz, CDCl3) d: 22.95, 23.23, 46.03,
51.75, 60.02, 125.42, 127.14, 127.53, 128.37, 142.03, 142.51, 166.97.
Compound 3i. Yellowish liquid; IR (liquid film): 693, 750, 813, 996, 1115,
1153, 1286, 1322, 1437, 1511, 1603, 1715, 2951, 3013, 3051, 3393; 1H NMR
(400 MHz, CDCl3) d: 3.73 (s, 3H), 5.23 (s, br, 1H, NH), 5.63 (s, 1H), 6.01 (s, 1H),
6.34 (s, 1H), 6.64 (d, 2H, J ¼ 8.0 Hz), 6.70 (t, 1H, J ¼ 7.2 Hz), 7.18 (m, 3H), 7.48
(d, 1H, J ¼ 8.0 Hz), 7.63 (m, 1H), 8.57 (d, 1H, J ¼ 4.8 Hz); 13C NMR (100 MHz,
CDCl3) d: 52.01, 58.61, 113.50, 117.72, 122.63, 122.76, 126.82, 129.29, 136.85,
139.63, 146.30, 149.39, 159.00, 166.91.
Compound 3j. Yellowish liquid; IR (liquid film): 692, 751, 817, 1015, 1093,
1
1155, 1286, 1436, 1503, 1602, 1716, 2951, 3019, 3052, 3401; H NMR (400 MHz,
CDCl3) d: 3.71 (s, 3H), 4.24 (s, br, 1H, NH), 5.38 (s, 1H), 5.96 (s, 1H), 6.40 (s,
1H), 6.57 (d, 2H, J ¼ 8.0 Hz), 6.74 (t, 1H, J ¼ 7.2 Hz), 7.16 (t, 2H, J ¼ 7.6 Hz), 7.31
(m, 4H); 13C NMR (100 MHz, CDCl3) d: 51.65, 57.99, 113.11, 117.79, 126.34,
128.47, 128.51, 128.82, 133.18, 138.63, 139.18, 146.07, 166.00.
Compound 3k. Yellowish liquid; IR (liquid film): 692, 751, 1037, 1099, 1155,
1268, 1437, 1503, 1601, 1720, 2951, 3019, 3053, 3401; 1H NMR (400 MHz, CDCl3) d:
3.73 (s, 3H), 3.92 (s, br, 1H, NH), 5.80 (s, 1H), 5.84 (s, 1H), 6.43 (s, 1H), 6.57 (d, 2H,
J ¼ 7.2 Hz), 6.73 (m, 1H), 7.15 (t, 1H, J ¼ 7.2 Hz), 7.24 (m, 2H), 7.40 (d, 2H,
J ¼ 2.4 Hz); 13C NMR (100 MHz, CDCl3) d: 52.18, 55.39, 113.40, 118.15, 127.11,
127.76, 128.34, 129.04, 129.23, 130.05, 134.09, 137.75, 139.42, 146.40, 166.55.
Compound 3l. Yellowish liquid; IR (liquid film): 693, 751, 821, 1101, 1157,
1
1224, 1287, 1437, 1506, 1603, 1717, 2952, 3019, 3052, 3400; H NMR (400 MHz,
CDCl3) d: 3.70 (s, 3H), 4.17 (s, br, 1H, NH), 5.39 (s, 1H), 5.96 (s, 1H), 6.39 (s,
1H), 6.57 (d, 2H, J ¼ 7.6 Hz), 6.73 (t, 1H, J ¼ 7.6 Hz), 7.02 (t, 1H, J ¼ 8.4 Hz), 7.23
(m, 2H), 7.34 (m, 2H); 13C NMR (100 MHz, CDCl3) d: 21.14, 51.90, 55.75, 59.55,
114.76, 125.97, 127.46, 129.42, 137.47, 137.78, 140.33, 140.85, 152.37, 166.78.
Compound 3m. Yellowish liquid; IR (liquid film): 694, 751, 850, 1018, 1067,
1
1124, 1164, 1326, 1504, 1603, 1717, 2954, 3019, 3056, 3400; H NMR (400 MHz,
CDCl3) d: 3.72 (s, 3H), 4.42 (s, br, 1H, NH), 5.47 (s, 1H), 6.00 (s, 1H), 6.44

1960
S.-Q. GE, Y.-Y. HUA, AND M. XIA
(s, 1H), 6.60 (d, 2H, J ¼ 8.0 Hz), 6.77 (d, 1H, J ¼ 7.2 Hz), 7.17 (dd, 2H, J1 ¼ 7.2 Hz,
J2 ¼ 8.0 Hz), 7.51 (d, 2H, J ¼ 8.0 Hz), 7.59 (d, 2H, J ¼ 8.0 Hz); 13C NMR (100 MHz,
CDCl3) d: 52.13, 58.93, 113.88, 118.73, 122.67, 125.37, 125.69, 125.72, 125.76,
125.80, 127.34, 127.83, 129.30, 129.86, 130.19, 139.40, 166.27.
Compound 3n. Yellowish liquid; IR (liquid film): 742, 817, 1011, 1072, 1153,
1
1195, 1273, 1438, 1486, 1505, 1596, 1627, 1716, 2848, 2949, 3032, 3352; H NMR
(400 MHz, CDCl3) d: 3.46 (s, br, 3H, -NH- and -NH2), 3.71 (s, 3H), 5.37 (s, 1H),
5.89 (s, 1H), 6.73 (s, 1H), 6.49 (d, 1H, J ¼ 7.2 Hz), 6.73 (m, 3H), 7.28 (d, J ¼ 7.6 Hz,
2H), 7.44 (d, J ¼ 7.6 Hz, 2H); 13C NMR (100 MHz, CDCl3) d: 52.05, 58.35, 113.73,
116.87, 119.59, 120.58, 121.71, 126.56, 129.34, 131.84, 134.58, 135.75, 139.85,
139.92, 166.51.
Compound 3o. Yellowish liquid; IR (liquid film): 817, 1037, 1086, 1154,
1
1248, 1512, 1718, 2951, 2999, 3393; H NMR (400 MHz, CDCl3) d: 2.33 (s, 3H),
3.69 (s, 3H), 3.72 (s, 3H), 4.00 (s, br, 1H, NH), 5.29 (s, 1H), 5.97 (s, 1H), 6.36 (s,
1H), 6.53 (d, 2H, J ¼ 8.8 Hz), 6.75 (d, 2H, J ¼ 8.8 Hz), 7.13 (d, 2H, J ¼ 7.6 Hz),
7.25 (d, 2H, J ¼ 8.0 Hz); 13C NMR (100 MHz, CDCl3) d: 21.14, 51.90, 55.75,
59.55, 114.76, 125.97, 127.46, 129.42, 137.47, 137.78, 140.33, 140.85, 152.37, 166.78.
Compound 3p. Yellowish liquid; IR (liquid film): 732, 763, 1138, 1194, 1270,
1438, 1497, 1594, 1667, 1721, 2951, 2990, 3068, 3296; 1H NMR (400 MHz, CDCl3) d:
2.15 (s, 3H), 2.83 (s, 3H), 3.75 (s, 3H), 5.29 (s, br, 1H, NH), 5.75 (s, 1H), 5.80 (s, 1H),
6.39 (s, 1H), 7.23 (d, 2H, J ¼ 5.2 Hz), 7.38 (s, 1H), 7.42 (m, 4H), 7.53 (d, 1H,
J ¼ 7.6 Hz); 13C NMR (100 MHz, CDCl3) d: 10.08, 37.60, 52.17, 57.27, 119.46,
123.04, 126.12, 127.10, 127.41, 129.10, 129.51, 129.54, 133.84, 134.42, 135.13,
137.05, 140.43, 140.83, 162.10, 166.37.
Compound 3q. Yellowish solid; mp 85–87 ꢁC; IR (KBr): 682, 766, 818, 868,
990, 1046, 1088, 1143, 1195, 1276, 1385, 1438, 1483, 1598, 1719, 2952, 3023, 3089,
1
3393; H NMR (400 MHz, CDCl3) d: 3.74 (s, 3H), 4.24 (s, br, 1H, NH), 5.76 (d,
2H, J ¼ 9.2 Hz), 6.39 (dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 8.4 Hz), 6.44 (s, 1H), 6.52 (t, 1H,
J ¼ 2.0 Hz), 6.68 (dd, 1H, J1 ¼ 1.2 Hz, J2 ¼ 7.6 Hz), 7.04 (t, 1H, J ¼ 8.0 Hz), 7.21
(dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 8.4 Hz), 7.32 (d, 1H, J ¼ 7.6 Hz), 7.43 (d, 1H, J ¼ 2.0 Hz);
13C NMR (100 MHz, CDCl3) d: 52.29, 55.07, 111.47, 113.18, 118.30, 127.47, 128.15,
129.15, 129.96, 130.30, 134.37, 134.71, 135.00, 136.04, 138.71, 147.38, 166.17.
Compound 3r. Red liquid; IR (liquid film): 423, 456, 570, 738, 769, 818, 866,
964, 1049, 1107, 1143, 1196, 1286, 1346, 1385, 1408, 1437, 1470, 1525, 1582, 1630,
1
1716, 2858, 2951, 3010, 3061, 3424; H NMR (400 MHz, CDCl3) d: 3.75 (s, 3H),
5.03 (s, br, 1H, NH), 5.85 (s, 1H), 5.98 (s, 1H), 6.40 (t, 1H, J ¼ 4.4 Hz), 6.46 (s,
1H), 7.18 (dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 8.4 Hz), 7.25 (m, 2H), 7.43 (m, 4H), 7.80 (m,
2H); 13C NMR (100 MHz, CDCl3) d: 52.31, 55.42, 105.96, 118.39, 119.79, 123.38,
125.03, 125.87, 126.49, 127.51, 128.42, 128.83, 129.37, 129.93, 134.25, 134.31,
134.81, 136.31, 138.71, 141.13, 166.49.
Compound 3s. Yellowish liquid; IR (liquid film): 731, 820, 1015, 1089, 1114,
1156, 1238, 1438, 1514, 1628, 1713, 2952, 3030, 3397; 1H NMR (400 MHz, CDCl3) d:
3.70 (s, 3H), 3.84 (s, br, 1H, NH), 5.28 (s, 1H), 5.93 (s, 1H), 6.38 (s, 1H), 6.47 (d, 2H,
J ¼ 8.8 Hz), 6.66 (d, 2H, J ¼ 8.8 Hz), 7.30 (m, 4H); 13C NMR (100 MHz, CDCl3)

AMINATION OF BAYLIS–HILLMAN ACETATES
1961
d: 52.13, 59.30, 115.13, 116.12, 126.89, 128.88, 133.50, 139.29, 140.00, 140.39, 148.41,
166.76.
Compound 3t. Yellowish liquid; IR (liquid film): 511, 644, 733, 807, 887, 959,
1015, 1090, 1127, 1154, 1194, 1286, 1406, 1437, 1489, 1519, 1617, 1717, 2866, 2919,
2951, 3022, 3401;1H NMR (400 MHz, CDCl3) d: 2.22 (s, 3H), 3.69 (s, 3H), 4.05 (s,
br, 1H, NH), 5.34 (s, 1H), 5.94 (s, 1H), 6.38 (s, 1H), 6.48 (d, 2H, J ¼ 8.4 Hz), 6.96
(d, 2H, J ¼ 8.4 Hz), 7.28 (d, 4H, J ¼ 9.2 Hz); 13C NMR (100 MHz, CDCl3) d:
20.43, 52.00, 58.75, 113.74, 126.68, 127.51, 128.91, 129.75, 133.55, 139.31, 139.91,
144.12, 166.51.
ACKNOWLEDGMENTS
We are grateful for the financial support from the Natural Science Foundation
of Zhejiang Province (Project No. R405465) and Program for Changjiang Scholars
and Innovative Research Team in University (PCSIRT) (No. 0654).
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