Synthesis of functionalized β-enamino compounds by carbon-fragment transfer reaction of C(2)-substituted imidazolidines with amines

Article abstract of DOI:10.3987/COM-07-11284

The substituted imidazolidines (2, 3, 5) and a ring-opening product, N,N,N'-trisubstituted 2-methyl-ethylenediamines (4), derived from addition of the carbon anions to 1-tosyl-3,4-dimethylimidazolinium iodide (1), were utilized to transfer substituted one-carbon units to various amines to yield a series of functionalized β-enamino compounds.

Full text of DOI:10.3987/COM-07-11284

HETEROCYCLES, Vol. 75, No. 5, 2008
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HETEROCYCLES, Vol. 75, No. 5, 2008, pp. 1123 - 1131. © The Japan Institute of Heterocyclic Chemistry
Received, 29th November, 2007, Accepted, 15th January, 2008, Published online, 18th January, 2008. COM-07-11284
SYNTHESIS OF FUNCTIONALIZED β-ENAMINO COMPOUNDS BY
CARBON-FRAGMENT TRANSFER REACTION OF C(2)-SUBSTITUTED
IMIDAZOLIDINES WITH AMINES
Yongbin Zhang, Donghong Li, Guofu Zhou, Chizhong Xia, and Wei Guo*
School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan
030006, China; Email: guowsxu@yahoo.com.cn; Fax: 0086-351-7011600
Abstract –The substituted imidazolidines (2, 3, 5) and a ring-opening product,
N,N,N′-trisubstituted 2-methyl-ethylenediamines (4), derived from addition of the
carbon anions to 1-tosyl-3,4-dimethylimidazolinium iodide (1), were utilized to
transfer substituted one-carbon units to various amines to yield a series of
functionalized β-enamino compounds.
INTRODUCTION
β-Enamino compounds are versatile structures for the synthesis of natural therapeutic and synthetic
biologically active analogues including taxol,1-4 anticonvulsivant,5,6 and antitumor agents,5,7 as well as
quinolone antibacterials and quinoline antimalarials.8,9 Among the methods for generating β-enamino
compounds, condensation of amines and β-dicarbonyl compounds is a classical method in which the
azeotropic removal of water is affected by refluxing in aromatic solvent.10-13 Treatment of amines with
β,β-diactivated alkoxymethylene derivatives is another attractive method for the preparation of
β-enamino compounds.14-16 Under ultrasound in the presence of acetic acid, condensation of β-keto esters
and amines gave good yields of the corresponding β-enamino esters.17 A variety of other methods
utilizing SiO2, montmorillonite K10, and NaAuCl4 as catalysts have also been revealed.18-21 In this paper,
we provide a novel method for preparing functionalized β-enamino compounds by the carbon-fragment
transfer reactions of C(2)-substituted imidazolidines with amines.
RESULTS AND DISCUSSION
In our earlier research, a series of dihydroimidazolium iodides salts were synthesized as the
tetrahydrofolate coenzyme model for the study of one-carbon unit transfer reactions.22-25 Recently, we
designed and synthesized a more activated model compound, 1-tosyl-3,4-dimethylimidazolinium iodide
(1) by the adjusting the number of substituted methyl in imidazoline ring.26 Furthermore, we found that

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HETEROCYCLES, Vol. 75, No. 5, 2008
compound (1) could easily react with carbon anions to produce the substituted imidazolidines (2, 3, 5),27
and a ring-opening products, N,N,N′-trisubstituted 2-methyl-ethylenediamines (4)26 in good yields
(Scheme 1). We speculated that compounds (2-5) can also be regarded as subsitituted folate models, and
can transfer the N(1),N(3)-bonded carbon fragment to amines to produce functionalized β-enamino
compounds. The observed results were found to be in agreement with our assumption. When compounds
(2-5) were treated with tryptamine in refluxing acetonitrile, the corresponding complete carbon-fragment
transfer product, β-enamino compounds, were produced, which have been used to prepare tetrahydro-β-
carboline derivatives through Pictet-Spengler reaction by us.27
O
N
O
O
N
O
Me
Ts
Me
Me
Me
Ts
OEt
Me
N
N
O
O
Me
Me
O
O
N
2
3
a
Me
Me
H
,
Me
OEt
Me
T
H
F
I
O
Ts
N
N
Me
F
H
T
,
Me
H
1
MeNO2
a
O2N
N
Me
O
Ts NH
N
Me
Ts
N
N
Me
Me
4
5
Me
Scheme 1
In order to exploit the generality of this method for preparing various functionalized β-enamino
compounds, a series of amines including aromatic amines, benzyl amine, amino acid methyl esters, and
phenethylamine derivatives were tested in the current research, and results are summarized in Tables 1, 2.
All reactions were refluxed in acetonitrile and easily followed by TLC. The reaction time was generally
from 1 to 10 h and workup was straightforward. The results obtained suggested that compounds (2, 3) are
enough active and can react with all amines tested in moderate to good yields (Table 1); however,
compounds (4, 5) are less-active and fail to react with aromatic amines and amino acid methyl esters
(Table 2). It is noteworthy that in the four compounds, low yields and incomplete reactions were only
observed with compound 4 even in the lengthening time, and yields vary from 14% to 58%. For the
compound 5, the long reaction time are usually required in order to obtained good yields. All of the
1
products obtained were identified by H NMR, IR, MS, and Elemental Analysis. However, an effort in
reacting a ring-opening product, derived from addition of the malononitrile carbon anions to

HETEROCYCLES, Vol. 75, No. 5, 2008
1125
1-tosyl-3,4-dimethylimidazolinium iodide (1),26 with various amines is unsuccessful due to its poor
reactivity.
Table 1. Carbon-fragment transfer reactions of compounds (2 and 3) with various amine.
O
O
Me
O
Me
Ts
R1
O
R1
R
NH2
N
N
Me
HN
H
R
Me
2, R = Me; 3, R = OEt
6 - 25
Product (Yield)
H
N
MeO
MeO
O
R =
O
Me
R1 = Me
R1 = OEt
6(79%)
7(77%)
8(73%)
9(78%)
19(89%)
10(71%)
20(70%)
16(59%)
18(67%)
17(88%)
OMe
MeO
MeO
R =
N
H
HO
R1 = Me
R1 = OEt
11(75%)
21(75%)
12(69%)
22(77%)
13(71%)
23(68%)
14(81%)
24(82%)
15(86%)
25(86%)
Table 2. Carbon-fragment transfer reactions of compounds (4 and 5) with various amine.
O2N
H
H
NO2
Me
Me
H
O
O
R
NH2
R
NH2
(2)
(1)
;
Ts NH
N
Me
NH
R
Ts
N
N
Me
HN
R
Me
4
Me
26 - 32
5
33 - 39
Product (Yield)
OMe
MeO
R =
N
Me
MeO
HO
H
26(39%)
33(91%)
27(35%)
34(96%)
28(58%)
35(87%)
29(14%)
36(84%)
30(40%)
37(56%)
31(44%)
38(74%)
32(24%)
39(90%)
The stereochemistry of compounds (16-25) was deduced to be E-type by the intramolecular hydrogen
1
bonding of N-H group and adjacent carbonyl group for each compound (in H NMR, the NH hydrogen
atom is shifted downfield, from 10.97 to 12.76), which can further be suggested by the crystal structures
of compounds (24, 25) (for 24, see Figure 1; for 25, see reference 28). The Z geometry in compounds
(26-39) is secured by intramolecular hydrogen bonding between nitro O atom (for 26-32) or carbonyl O

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HETEROCYCLES, Vol. 75, No. 5, 2008
1
atom (for 33-39) and the adjacent N-H group (in H NMR, the NH hydrogen atom is shifted downfield,
from 9.12 to 10.92).
Figure 1 X-Ray structure of compound (24).
The possible mechanism of the transformation of the carbon fragment to amines is described in Scheme 2.
According to this mechanism, the substituted imidazolidines (2, 3 and 5) undergo ring opening to give
enamine system (a). This is followed by addition of amines and, via the intermediate (b), results in the
production of the β-enamino compounds. The thermodynamically favored form of 4 is a ring-opening
product, which is possibly attacked straightforward by amines to give, via intermediate (b), β-enamino
compounds.
O
O
OH
R
2
O
1
R
R
1
H
2
R
R
N
2
R
1
Ts NH HN Me
Me
R
R
1
R
2
Ts
N
N
Me
Ts NH
N
Me
Ts NH
N
Me
R
NH
2
HN
R
Me
Me
Me
b
a
Scheme 2
In conclusion, the present research revealed a new method for the synthesis of a series of functionalized
β-enamino compounds by the carbon-fragment transfer reactions of C(2)-substituted imidazolidines, and
may enable chemical and biological studies on these compounds.
EXPERIMENTAL
1
MS spectra were obtained on a JMS-D300 GC/MS spectrometer. The H NMR spectra were recorded at
300MHz with TMS as a spectra standard. Combustion analyses were performed on a Perkin-Elmer 240C
or a MOD 1106 instrument. IR spectra were obtained on a Shimadzu IR-1700 spectrophotometer. The
TLC was carried out on silica gel GF-254 20*20 cm2 plate. Melting points were uncorrected. All reagents
and solvents were purified and dried as required. The synthesis procedures of compounds (2-5) and the
spectrum datas of compounds (15, 25, 28, 35) have been reported in our previous paper.27 Products (10,29

HETEROCYCLES, Vol. 75, No. 5, 2008
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19,30 and 2029) are known compounds, and the NMR spectra of the compounds are in agreement with
reported data.
General procedure for the reaction of compounds (2-5) with a series of amines.
Compounds (2-5) (1 mmol) and amine (1 mmol) were refluxed in dry MeCN (10 mL) and monitored by
TLC. Upon completion or after the indicated reaction time, the mixture was concentrated, and purified by
column chromatography on silica gel to give the desired products (6-39).
Compound (6): yield 79% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 1.90 (s, 3H), 2.43 (s, 3H),
2.97 (m, 1H), 3.29 (m, 1H), 3.79 (s, 3H), 4.13 (m, 1H), 7.08-7.15 (m, 3H), 7.27-7.33 (m, 3H), 11.01 (br,
1H); IR (KBr) cm-1: 2927, 1745, 1581, 1495, 1367, 1178, 979; MS m/z: 290 (M+1); Anal. Calcd for
C16H19NO4: C, 66.42; H, 6.62; N, 4.84. Found C, 66.23; H, 6.30; N, 4.88.
Compound (7): yield 77% as yellow oil. H-NMR (300 MHz, δ ppm, CDCl3): 2.39 (s, 3H), 2.57 (s, 3H),
7.23 (m, 3H), 7.42 (m, 2H), 8.22 (d, J = 12.7, 1H), 12.78 (br, 1H); IR (KBr) cm-1: 3053, 2925, 1745, 1627,
1600, 1504, 1398, 1259, 1184, 1028; MS m/z: 203 (M+); Anal. Calcd for C12H13NO2: C, 70.92; H, 6.45;
N, 6.89. Found C, 71.11; H, 6.54; N, 6.93.
o
Compound (8): yield 73%, recrystallized from EtOH as white crystals, mp 138~140 C. H-NMR (300
MHz, δ ppm, CDCl3): 1.70 (s, 3H), 2.70 (s, 3H), 3.16 (m, 1H), 3.54 (m, 1H), 3.83 (s, 3H), 4.29 (m, 1H),
7.03 (d, J = 13.1, 2H), 7.15 (m, 2H), 7.37 (d, J = 7.9, 1H), 7.56 (d, J = 7.7, 1H), 8.29 (s, 1H), 11.22 (br,
1H); IR (KBr) cm-1: 3190, 2922, 2873, 1739, 1625, 1562, 1398, 1178; MS m/z: 329 (M+1); Anal. Calcd
for C18H20N2O4: C, 65.84; H, 6.14; N, 8.53. Found C, 65.75; H, 6.28; N, 8.83.
o
1
Compound (9): yield 78%, recrystallized from EtOH as white crystals, mp 81~83 C. H-NMR (300
MHz, δ ppm, CDCl3): 2.25 (s, 3H), 2.49 (s, 3H), 4.55 (d, J = 5.9, 2H), 7.36 (m, 5H), 7.78 (d, J = 13.1,
1H), 11.32(br, 1H); IR (KBr) cm-1: 3430, 3173, 2924, 1858, 1613, 1573, 1498, 1443, 1394, 1354, 1245,
1181, 1028; MS m/z: 217 (M+); Anal. Calcd for C13H15NO2: C, 71.87; H, 6.96; N, 6.45. Found C, 71.85;
H, 7.07; N, 6.68.
Compound (11): yield 75% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 2.04 (s, 3H), 2.40 (s, 3H),
2.77 (m, 2H), 3.54 (m, 2H), 3.78 (s, 6H), 6.64 (m, 2H), 6.75 (d, J = 7.9, 1H), 7.44 (d, J = 13.2, 1H), 10.99
(br, 1H); IR (KBr) cm-1: 3481, 3196, 2936, 1621, 1516, 1463, 1395, 1356, 1262, 1182, 1027; MS m/z:
291 (M+); Anal. Calcd for C16H21NO4: C, 65.96; H, 7.27; N, 4.81. Found C, 65.77; H, 7.38; N, 4.97.
Compound (12): yield 69% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 2.04 (s, 3H), 2.45 (s, 3H),
2.90 (t, J = 6.7, 2H), 3.57 (m, 2H), 7.17 (d, J = 7.3, 2H), 7.32 (m, 3H), 7.36 (d, J = 13.2, 1H), 11.03 (br,
1H); IR (KBr) cm-1: 3199, 3028, 2927, 1722, 1622, 1585, 1497, 1455, 1396, 1356, 1259, 1088; MS m/z:
231 (M+); Anal. Calcd for C14H17NO2: C, 72.70; H, 7.41; N, 6.06. Found C, 72.76; H, 7.44; N, 6.17.
Compound (13): yield 71% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 1.99 (s, 3H), 2.39 (s, 3H),
2.86 (t, J = 6.6, 2H), 3.48 (m, 2H), 3.74 (s, 3H), 6.83 (m, 2H), 7.00 (d, J = 7.2, 1H), 7.17 (t, J = 7.8, 1H),

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HETEROCYCLES, Vol. 75, No. 5, 2008
7.35 (d, J = 13.3, 1H), 11.02 (br, 1H); IR (KBr) cm-1: 3433, 3198, 2926, 1722, 1622, 1586, 1495, 1463,
1439, 1394, 1246, 1183, 1028; MS m/z: 261 (M+); Anal. Calcd for C15H19NO3: C, 68.94; H, 7.33; N, 5.36.
Found C, 69.25; H, 7.63; N, 5.52.
Compound (14): yield 81%, recrystallized from EtOH as yellow crystals, mp 166~167 oC. 1H-NMR (300
MHz, δ ppm, CDCl3): 1.98 (s, 3H), 2.46 (s, 3H), 2.83 (t, J = 6.3, 2H), 3.55 (m, 2H), 6.22 (br, 1H), 6.78 (d,
J = 7.9, 2H), 7.00 (d, J = 7.9, 2H), 7.38 (d, J = 13.3, 1H), 11.01 (br, 1H); IR (KBr) cm-1: 3424, 3124,
3015, 2924, 1730, 1651, 1586, 1513, 1455, 1401, 1257, 1237, 1107; MS m/z: 247 (M+); Anal. Calcd for
C14H17NO3: C, 68.00; H, 6.93; N, 5.66. Found C, 67.94; H, 7.10; N, 6.14.
1
Compound (16): yield 59% as yellow oil. H-NMR (300 MHz, δ ppm, CDCl3): 1.26 (m, 3H), 2.44 (s,
3H), 3.11 (m, 2H), 3.76 (s, 3H), 4.11 (m, 2H), 4.25 (m, 1H), 7.08-7.30 (m, 5H), 7.60 (d, J = 13.3, 1H),
10.97 (br, 1H); IR (KBr) cm-1: 2979, 1741, 1693, 1635, 1575, 1490, 1454, 1382, 1245, 1062; MS m/z:
319 (M+); Anal. Calcd for C17H21NO5: C, 63.94; H, 6.63; N, 4.39. Found C, 63.88; H, 6.58; N, 4.24.
Compound (17): yield 88% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 1.35 (t, J = 7.1, 3H), 2.54
(s, 3H), 4.28 (m, 2H), 7.27 (m, 3H), 7.40 (m, 2H), 8.52 (d, J = 13.1, 1H), 12.76 (br, 1H); IR (KBr) cm-1:
3049, 2965, 1741, 1648, 1594, 1544, 1389, 1275, 1158, 1047; MS m/z: 233 (M+); Anal. Calcd for
C13H15NO3: C, 66.94; H, 6.48; N, 6.00. Found C, 67.21; H, 6.52; N, 6.17.
Compound (18): yield 67%, recrystallized from EtOAc/petroleum ether as yellow crystals, mp 84~87 oC.
1H-NMR (300 MHz, δ ppm, CDCl3): 1.17 (t, J = 7.1, 3H), 2.46 (s, 3H), 3.27 (m, 1H), 3.47 (m, 1H), 3.75
(s, 3H), 4.07 (m, 2H), 4.30 (m, 1H), 7.02-7.58 (m, 6H), 8.33 (br, 1H), 11.03 (br, 1H); IR (KBr) cm-1:
3435, 2976, 1730, 1699, 1635, 1566, 1419, 1386, 1178; MS m/z: 358 (M+); Anal. Calcd for C19H22N2O5:
C, 63.67; H, 6.19; N, 7.82. Found C, 63.51; H, 6.21; N, 7.69.
o
Compound (21): yield 75%, recrystallized from EtOAc/petroleum ether as white crystals, mp 88~90 C.
1H-NMR (300 MHz, δ ppm, CDCl3): 1.26 (t, J = 7.1, 3H), 2.45 (s, 3H), 2.81 (t, J = 6.8, 2H), 3.53 (m, 2H),
3.85 (s, 6H), 4.16 (m, 2H), 6.72 (m, 3H), 7.85 (d, J = 13.6, 1H), 11.06 (br, 1H); IR (KBr) cm-1: 3428,
3192, 2939, 1697, 1637, 1582, 1516, 1467, 1419, 1365, 1248, 1233, 1055; MS m/z: 321 (M+); Anal.
Calcd for C17H23NO5: C, 63.54; H, 7.21; N, 4.36. Found C, 63.22; H, 7.15; N, 4.52.
Compound (22): yield 77% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 1.24 (t, J = 6.8, 3H), 2.43
(s, 3H), 2.85 (t, J = 6.5, 2H), 3.54 (m, 2H), 4.14 (m, 2H), 7.22 (m, 5H), 7.79 (d, J = 13.5, 1H), 11.01 (br,
1H); IR (KBr) cm-1: 3184, 3028, 2980, 1694, 1633, 1583, 1497, 1455, 1418, 1383, 1250, 1071; MS m/z:
261 (M+); Anal. Calcd for C15H19NO3: C, 68.94; H, 7.33; N, 5.36. Found C, 68.56; H, 7.21; N, 5.76.
o
Compound (23): yield 68%, recrystallized from EtOAc/petroleum ether as white crystals, mp 49~51 C.
1H-NMR (300 MHz, δ ppm, CDCl3): 1.28 (t, J = 7.1, 3H), 2.45 (s, 3H), 2.94 (t, J = 6.9, 2H), 3.54 (m, 2H),
3.83 (s, 3H), 4.15 (m, 2H), 6.88 (m, 2H), 7.11 (d, J = 7.2, 1H), 7.24 (m, 1H), 7.88 (d, J = 13.7, 1H), 11.00
(br, 1H); IR (KBr) cm-1: 3430, 3191, 3028, 2926, 1693, 1636, 1587, 1494, 1461, 1419, 1386, 1251, 1067;

HETEROCYCLES, Vol. 75, No. 5, 2008
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MS m/z: 291 (M+); Anal. Calcd for C16H21NO4: C, 65.96; H, 7.27; N, 4.81. Found C, 65.79; H, 7.22; N,
4.86.
o
1
Compound (24): yield 82%, recrystallized from EtOAc as yellow crystals, mp 116~117 C. H-NMR
(300 MHz, δ ppm, CDCl3): 1.31 (t, J = 7.1, 3H), 2.46 (s, 3H), 2.82 (t, J = 6.2, 2H), 3.55 (m, 2H), 4.18 (m,
2H), 6.78 (d, J = 8.0, 2H), 6.83 (s, 1H), 7.00 (d, J = 7.9, 2H), 7.87 (d, J = 13.7, 1H), 10.94 (br, 1H); IR
(KBr) cm-1: 3297, 3027, 2941, 1659, 1633, 1590, 1518, 1449, 1417, 1387, 1259, 1221, 1065; MS m/z:
278 (M+1); Anal. Calcd for C15H19NO4: C, 64.97; H, 6.91; N, 5.05. Found C, 64.90; H, 6.89; N, 5.27.
Compound (26): yield 39% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 1.00 (t, J = 7.3, 3H), 1.40
(m, 2H), 1.64 (m, 2H), 3.37 (m, 2H), 6.47 (d, J = 5.6, 1H), 6.73 (m, 1H), 9.14 (br, 1H); IR (KBr) cm-1:
3060, 2931, 2873, 1340, 1137; MS m/z: 144 (M+); Anal. Calcd for C6H12N2O2: C, 49.98; H, 8.39; N,
19.43. Found C, 49.85; H, 8.35; N, 19.52.
Compound (27): yield 35% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 4.55 (s, 2H), 6.50 (d, J =
5.8, 1H), 6.81 (m, 1H), 7.28-7.44 (m, 5H), 9.34 (br, 1H); IR (KBr) cm-1: 3031, 2875, 1622, 1558, 1456,
1338, 1141; MS m/z: 178 (M+); Anal. Calcd for C9H10N2O2: C, 60.66; H, 5.66; N, 15.72. Found C, 60.75;
H, 5.61; N, 15.43.
Compound (29): yield 14% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 2.88 (t, J = 6.5, 2H), 3.61
(m, 2H), 3.89 (s, 6H), 6.41 (d, J = 5.7, 1H), 6.54 (m, 1H), 6.70-6.87 (m, 3H), 9.16 (br, 1H); IR (KBr)
cm-1: 3057, 2935, 2837, 1622, 1593, 1517, 1465, 1093; MS m/z: 252 (M+); Anal. Calcd for C12H16N2O4:
C, 57.13; H, 6.39; N, 11.10. Found C, 57.26; H, 6.44; N, 11.25.
Compound (30): yield 40% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 2.96 (t, J = 6.8, 2H), 3.62
(m, 2H), 6.39 (d, J = 5.7, 1H), 6.54 (m, 1H), 7.12-7.38 (m, 5H), 9.13 (br, 1H); IR (KBr) cm-1: 2927, 2864,
1622, 1541, 1454, 1141; MS m/z: 192 (M+); Anal. Calcd for C10H12N2O2: C, 62.49; H, 6.29; N, 14.57.
Found C, 62.35; H, 6.11; N, 14.38.
Compound (31): yield 44% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 2.96 (t, J = 6.6, 2H), 3.58
(m, 2H), 3.85 (s, 3H), 6.38 (d, J = 5.7, 1H), 6.52 (m, 1H), 6.90 (m, 2H), 7.17 (d, J = 7.0, 1H), 7.28 (m,
1H), 9.22 (br, 1H); IR (KBr) cm-1: 2939, 2837, 1622, 1589, 1494, 1122; MS m/z: 222 (M+); Anal. Calcd
for C11H14N2O3: C, 59.45; H, 6.35; N, 12.60. Found C, 59.66; H, 6.47; N, 12.85.
Compound (32): yield 24% as yellow oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 2.87 (t, J = 6.6, 2H), 3.56
(m, 2H), 6.40 (d, J = 5.7, 1H), 6.53 (m, 1H), 6.83 (d, J = 8.1, 2H), 7.07 (d, J = 8.1, 2H), 9.12 (br, 1H); IR
(KBr) cm-1: 3020, 2925, 2854, 1618, 1595, 1550, 1515, 1444, 1143; MS m/z: 208 (M+); Anal. Calcd for
C10H12N2O3: C, 57.68; H, 5.81; N, 13.45. Found C, 57.59; H, 5.76; N, 13.37.
1
Compound (33): yield 91% as colorless oil. H-NMR (300 MHz, δ ppm, CDCl3): 0.91 (t, J = 7.2, 3H),
1.31 (m, 2H), 1.49 (m, 2H), 1.83 (s, 3H), 3.25 (m, 2H), 6.98 (d, J = 13.7, 1H), 7.38 (m, 5H), 10.41 (br,
1H); IR (KBr) cm-1: 3238, 2929, 2858, 1635, 1577, 1440, 1371, 1136; MS m/z: 217 (M+); Anal. Calcd for

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C14H19NO: C, 77.38; H, 8.81; N, 6.45. Found C, 77.44; H, 8.89; N, 6.51.
Compound (34): yield 96% as colorless oil. 1H-NMR (300 MHz, δ ppm, CDCl3): 1.89 (s, 3H), 4.36 (d, J
= 5.3, 2H), 7.05 (d, J = 13.4, 1H), 7.23-7.28 (m, 4H), 7.36-7.48 (m, 6H), 10.75 (br, 1H); IR (KBr) cm-1:
3354, 2868, 2360, 1635, 1577, 1545, 1396, 1218, 1016; MS m/z: 251 (M+); Anal. Calcd for C17H17NO: C,
81.24; H, 6.82; N, 5.57. Found C, 81.63; H, 6.97; N, 5.88.
Compound (36): yield 84%, recrystallized from EtOH as yellow crystals, mp 120~122 oC. 1H-NMR (300
MHz, δ ppm, CDCl3): 1.79 (s, 3H), 2.77 (t, J = 6.4, 2H), 3.40 (m, 2H), 3.86 (s, 3H), 3.90 (s, 3H),
6.65-6.86 (m, 4H), 7.34-7.44 (m, 5H), 10.79 (br, 1H); IR (KBr) cm-1: 3350, 2931, 2837, 1635, 1539, 1514,
1440, 1365, 1137; MS m/z: 325 (M+); Anal. Calcd for C20H23NO3: C, 73.82; H, 7.12; N, 4.30. Found C,
73.79; H, 7.15; N, 4.29.
o
1
Compound (37): yield 56%, recrystallized from EtOH as white crystals, mp 153~154 C. H-NMR (300
MHz, δ ppm, DMSO-d6): 1.68 (s, 3H), 2.73 (t, J = 6.0, 2H), 3.30 (m, 2H), 6.68 (d, J = 13.7, 1H),
6.95-7.36 (m, 10H), 10.92 (br, 1H); IR (KBr) cm-1: 3238, 2922, 1630, 1581, 1548, 1497, 1446, 1392,
1230, 1012; MS m/z: 265 (M+); Anal. Calcd for C18H19NO: C, 81.47; H, 7.22; N, 5.28. Found C, 81.11; H,
7.39; N, 5.14.
Compound (38): yield 74%, recrystallized from EtOH as yellow crystals, mp 120~121 oC. 1H-NMR (300
MHz, δ ppm, CDCl3): 1.79 (s, 3H), 2.84 (t, J = 6.3, 2H), 3.38 (m, 2H), 3.81 (s, 3H), 6.80-6.96 (m, 3H),
7.07 (d, J = 7.3, 1H), 7.28-7.41 (m, 6H), 10.76 (br, 1H); IR (KBr) cm-1: 3307, 2933, 1635, 1598, 1539,
1446, 1396, 1375, 1226, 1118; MS m/z: 295 (M+); Anal. Calcd for C19H21NO2: C, 77.26; H, 7.17; N, 4.74.
Found C, 77.17; H, 7.15; N, 4.69.
o
1
Compound (39): yield 90%, recrystallized from EtOH as white crystals, mp 189~190 C. H-NMR (300
MHz, δ ppm, DMSO-d6): 1.68 (s, 3H), 2.68 (t, J = 7.1, 2H), 3.22 (m, 2H), 6.59-7.35 (m, 11H), 9.24 (br,
1H), 10.86 (br, 1H); IR (KBr) cm-1: 3203, 2931, 1626, 1595, 1510, 1450, 1371, 1265, 1028; MS m/z: 281
(M+); Anal. Calcd for C18H19NO2: C, 76.84; H, 6.81; N, 4.98. Found C, 76.56; H, 7.08; N, 4.79.
Crystal data for compound (24).
Empirical formula: C15H19NO4, crystal size: 0.40×0.20×0.20, Triclinic, a = 8.637(3)Å, b = 9.418(3)Å, c =
9.944(3)Å, α = 66.706 (4)°, β = 89.808(4)°, γ = 77.424(4)°, V = 722.0(4), T = 293(2)K, space group P-1,
Z = 2, dcalc = 1.2767 g/cm3, F(000) = 296, 3000 reflections measured, 2298 unique (Rint= 0.0187). The
final R1 = 0.0762 (I > 2σ ), 0.0974 (all data), wR2 = 0.1875 (I > 2σ ), 0.2014 (all data).
ACKNOWLEDGEMENTS
We thank the National Natural Science Foundation of China (No. 20502014 and 20772073) for financial
support.

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