An efficient and green preparation of 9-arylacridine-1,8-dione derivatives

Article abstract of DOI:10.1002/hc.20410

9-Arylacridine-1,8-dione derivatives were prepared in an ionic liquid medium in the presence of CeCl₃ · 7H₂O through an one-pot procedure. The method presented here has the advantages of environmental benignancy, good-to-excellent yi

Full text of DOI:10.1002/hc.20410

Heteroatom Chemistry
Volume 18, Number 7, 2007
An Efficient and Green Preparation of
9-Arylacridine-1,8-dione Derivatives
Xuesen Fan, Yanzhen Li, Xinying Zhang, Guirong Qu,
and Jianji Wang
School of Chemical and Environmental Sciences, Henan Key Laboratory for Environmental
Pollution Control, Henan Normal University, Xinxiang, Henan 453007, People’s Republic of China
Received 14 March 2005; revised 22 April 2005
acridinediones have structural similarity to those
ABSTRACT: 9-Arylacridine-1,8-dione derivatives
of 1,4-dihydropyridines (1,4-DHPs), which are ver-
were prepared in an ionic liquid medium in the
satile intermediates in the synthesis of numerous
presence of CeCl3 · 7H2O through an one-pot pro-
pharmaceuticals including those for the treatment
cedure. The method presented here has the advan-
of cardiovascular diseases [6] and congestive heart
tages of environmental benignancy, good-to-excellent
failure [7]. Classical methods for the synthesis of
yields, and simple operational procedure. Moreover,
1,4-dihydropyridines involve the condensation of an
the solvent and catalyst can be easily recovered and
aldehyde with ethyl acetoacetate and ammonia ei-
reused for several runs without obvious loss of ac-
ther in acetic acid or in ethanol [8]. As for the prepa-
ꢀ
C
tivity.
2007 Wiley Periodicals, Inc. Heteroatom Chem
ration of acridine-1,8-diones, similar methods have
been employed and they are usually carried out in
organic solvents such as methanol or acetic acid
through a two-step procedure [9]. These procedures
usually require tedious works to isolate the inter-
mediate products and necessitate the use of classi-
cal organic solvents, which are inevitably hazardous
to some extent to the environment. Recently, it has
been reported that acridine-1,8-diones can also be
obtained under microwave irradiation conditions
[10]. Although microwave heating provides a time-
efficient methodology, more works are definitely still
needed to develop more practical and more environ-
mentally benign methods.
Recently, room temperature ionic liquids have
shown great promise as green reaction media in the
realm of synthetic organic chemistry [11]. Of partic-
ular interest are air and moisture stable imidazolium
ionic liquids, which have been used as solvents for
a large variety of organic reactions due to their fa-
vorable properties, such as nonvolatile, nonexplo-
sive, recyclable, easy to handle, and thermally robust
[12]. In many cases, the products are weakly soluble
in the ionic phase and thus can be easily separated
18:786–790, 2007; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.20410
INTRODUCTION
It has been reported that acridine-1,8-diones can be
used as laser dyes with very high-lasing efficiencies
[1,2]. In addition, they have attracted many inter-
ests in view of the unique photochemical and elec-
trochemical behavior of heterocyclic compounds.
In particular, they possess bichromophoric groups,
which enable them to act as both electron donors
and acceptors in the excited state [3,4] and, thus,
have been used in the photoinitiated polymeriza-
tion of acrylates and methacrylates [5]. Moreover,
Correspondence to: Xuesen Fan; e-mail: fanxs88@263.net.
Contract grant sponsor: National Natural Science Foundation
of China.
Contract grant number: 20573034.
Contract grant sponsor: Science Foundation of Henan Normal
University for Young Scholars.
Contract grant number: 0307032.
2007 Wiley Periodicals, Inc.
c
ꢀ
786

Efficient and Green Preparation of 9-Arylacridine-1,8-dione Derivatives 787
(Table 1, entry 2). To further improve the reaction, a
new operating procedure was then attempted by first
treating 2 (0.5 mmol) and 3 (1.2 mmol)∗ in 1.0 mL
ionic liquid together with 0.15 mmol CeCl3 · 7H2O.
After the mixture being stirred for 3 h at 55◦C, 2 was
completely consumed and the corresponding enam-
ine intermediate was formed (monitored by TLC).
Without isolating of this intermediate, 1a (0.5 mmol)
and another 0.5 mmol of 2 were added to the re-
SCHEME 1
action mixture. After being stirred at 100◦C for an-
other 3 h, it gave 4a with a very good yield (91%;
Table 1, entry 3). Furthermore, the optimal amount
of CeCl3 · 7H2O for this procedure was also investi-
gated (Table 1, entry 4–6). It soon turned out that as
less as 0.05 mmol CeCl3 · 7H2O was enough to give
a very good result as 0.15 mmol CeCl3 · 7H2O did
(Table 1, entry 5).
With the above result in hand, we then extended
this procedure to a variety of aromatic aldehydes.
It turned out that all the substrates investigated un-
derwent the reactions smoothly and gave the corre-
sponding products in good to excellent yields. The
results are summarized in Table 2. It should also be
noted here that all of the reactions were carried out
smoothly under mild conditions, and there was no
need to exclude moisture or oxygen from the reac-
tion system.
by filtration or simple extraction with ether [13].
Therefore, many problems arisen from the use of
volatile organic solvents can be avoided. On the other
hand, CeCl3 · 7H2O has recently emerged as an at-
tractive candidate as a moderate Lewis acid [14]
due to its relative nontoxicity, water stability, ready
availability at a low cost [15], and high selectivity as
a promoter. As part of our program aimed at de-
veloping environmental friendly methodologies in
organic synthesis, herein, we would like to report
an one-pot reaction of aldehyde (1), 5,5-dimethyl-
1,3-cyclohexandione (2), and ammonium bicarbon-
ate (3) for the preparation of acridine-1,8-dione (4)
promoted by a catalytic amount of cerium(III) chlo-
ride heptahydrate (CeCl3 · 7H2O) by using the ionic
liquid, 1-butyl-3-methyl-imidazolium tetrafluorobo-
rate ([bmim][BF4]) as solvent (Scheme 1).
With efforts for a greener chemistry, the possi-
bility of the recovery and reutilization of the catalyst
and solvent was then studied. At the completion of
the reaction, the product was in fact in a solid state
so it could be simply collected by suction. The filtrate
containing [bmim][BF4] together with the immobi-
lized Ce(III) was then dried at 100◦C for several hours
until its mass was independent of drying time. Inves-
tigations by using 1a as a model substrate showed
that successive reuse of the recovered ionic liquid
and catalyst in the same reaction gave the product
with a yield of 92%, even higher than that of the first
round (Table 3, entry 2). It also has been observed
that even in the fifth round, the corresponding prod-
uct still could be obtained with fairly good yield by
using the ionic liquid and the catalyst recovered from
the fourth round (Table 3, entry 5).
RESULTS AND DISCUSSION
We started our work by examining the possibility of
an one-pot reaction involving p-chlorobenzaldehyde
(1a), 2, and 3 to afford 3,3,6,6-tetramethyl-9-(4-
chlorophenyl)-3,4,5,6,9,10-hexahydroacridine-1,8
(2H,7H)-dione (4a) in ([bmim][BF4]) in the presence
or absence of CeCl3 · 7H2O (Scheme 2).
It turned out that after the mixture of 1a, 2,
and 3 in 1.0 mL [bmim][BF4] being stirred for 16
h at 80◦C, 4a could be obtained but with a rather
low yield (41%) (Table 1, entry 1). Then, 0.15 mmol
CeCl3·7H2O was introduced in the above reaction.
After being stirred at 80◦C for 10 h, it afforded 4a
with a much higher yield (68%), demonstrating obvi-
ous catalytic activity of CeCl3 · 7H2O for this reaction
Furthermore, it has been reported that ionic
liquids not only are able to be used as a green
recyclable alternative to classical organic solvents,
but also has the advantages of actually accelerating
∗
Because the ammonium bicarbonate was prone to decompose
and part of the ammonia would run out, the reaction would
carried out more efficiently if the addition of 3 was divided into
3 parts (i.e., first added 0.5 mmol, then another 0.5 mmol, at last
added 0.2 mmol).
SCHEME 2
Heteroatom Chemistry DOI 10.1002/hc

788 Fan et al.
TABLE 1 Reaction Condition Screening for the Preparation of the Compound of 4a
Entry
Amount of CeCl3·7H2O (mmol)
Reaction Time (h)
Reaction Temperature ( ◦C)
Isolated Yields (%)
1
2
3
4
5
6
0.00
0.15
0.15
0.10
0.05
0.025
16
10
3,3
3,3
3,3
4,4
80
80
55,100
55,100
55,100
55,100
41
68
91
91
89
80
TABLE 2 Preparation of 4a–4j Promoted by CeCl3 · 7H2O in
TABLE 4 The Preparation of 4a in Different Solvents
Reaction Reaction
[bmim][BF4]
Entry
Ar
p-ClC6H4
Productsa
Yield b (%)
Entry
Solvent
Time (h) Temperature ( ◦C) Yield (%)a,b
1
2
4a
4b
4c
4d
4e
4f
89
88
87
93
88
82
95
85
86
94
1
2
3
4
5
Ethanol
THF
CH2Cl2
CH3CN
[bmim][BF4]
3,3
3,3
6
3,3
3,3
55, reflux
55, reflux
Reflux
55, reflux
55, 100
48
37
42
54
89
C6H5
3
4
5
6
p-CH3C6H4
p-NO2C6H4
m-NO2C6H4
o-NO2C6H4
p-BrC6H4
a0.05 mmol CeCl3 · 7H2O was used for 0.5 mmol 1a and 1.0 mmol 2.
7
4g
4h
4i
bIsolated yields.
8
9
10
o-BrC6H4
o-ClC6H4
p-OH,m-OCH3C6H4
4j
aAll the products were characterized by their 1H NMR and IR spectra
and compared with authentic samples.
bIsolated yields.
In summary, this report discloses a novel
and simple method for the synthesis of 9-
arylacridine-1,8-dione derivatives. Advantages of
this CeCl3 · 7H2O catalyzed one-pot procedure in-
clude simple operational procedure, high efficiency,
mild reaction condition together with an environ-
mental friendly nature. Furthermore, the solvent and
catalyst can be easily recovered and reused. All of
these are expected to offer a green and efficient alter-
native for the synthesis of 9-arylacridine-1,8-diones.
the reaction process and increasing the yields com-
pared with classical solvents [16]. To clarify whether
[bmim][BF4] has such advantages in this reaction,
the above procedure was also tried in some tradi-
tional organic solvents, such as anhydrous ethanol,
THF, CH2Cl2, and CH3CN. By using 1a as the model
substrate again, investigation showed that through
similar operational procedure under similar reac-
tion conditions, reactions carried out in these or-
ganic solvents only gave the corresponding prod-
uct in rather disappointingly low yields compared
with the case when [bmim][BF4] was used (Table 4).
Moreover, the separation process was much more te-
dious in which several runs of extraction of the prod-
uct and removal of the solvents were necessitated.
EXPERIMENTAL
Melting points were measured by a Kofler mi-
cromelting point apparatus and were uncorrected.
Infrared spectra were recorded on a Bruker Vector
22 spectrometer in KBr with absorption in cm−1. 1H
NMR spectra were determined on a Bruker AC 400
spectrometer as CDCl3 solutions. Chemical shifts
(δ) are expressed in ppm downfield from the in-
ternal standard tetramethylsilane (TMS), and cou-
pling constants J are given in Hz. 13C NMR spectra
were determined on a Bruker AC 300 spectrometer
as CDCl3 solutions and using TMS as the internal
standard. Mass spectra were recorded on a HP5989B
mass spectrometer. Elemental analyses were per-
formed on an EA-1110 instrument.
TABLE 3 Reusability of [bmim][BF4] and the Catalyst for the
Preparation of 4b
Round
Ionic Liquid Recovered (%)
Yield (%)a,b
1
2
3
4
5
98
99
98
99
98
89
92
90
88
89
The ionic liquid [bmim][BF4] was prepared and
purified according to the literature procedure [17].
Other reagents were of reagent grade and were used
without further purification.
a0.05 mmol CeCl3 · 7H2O was used for 0.5 mmol 1a and 1.0 mmol 2.
bIsolated yields.
Heteroatom Chemistry DOI 10.1002/hc

Efficient and Green Preparation of 9-Arylacridine-1,8-dione Derivatives 789
2×CH3), 1.09 (s, 6H, 2×CH3), 2.08–2.44 (m, 8H,
4×CH2), 5.15 (s, 1H, CH), 6.14 (s, 1H, NH), 7.50 (d,
J = 8.0 Hz, 2H, ArH), 8.06 (d, J = 8.0 Hz, 2H, ArH);
General Procedure for the Preparation of
9-Arylacridine-1,8-dione Derivatives
First, 5,5-dimethyl-1,3-cyclohexanedione (2, 0.5
mmol) and ammonium bicarbonate (3, 1.2 mmol)
13C NMR (CDCl3, 300 MHz) δ: 27.13, 29.41, 32.72,
34.40, 41.25, 50.53, 112.81, 123.37, 129.02, 145.83,
147.84, 153.68, 195.07; IR (KBr): 3444 (NH), 1643
(C O), 1604 (N C C) cm−1; MS (70 eV) m/z: 394
(M+); Anal. Calcd. for C23H26N2O4: C, 70.03; H, 6.64;
N, 7.10. Found: C, 70.20; H, 6.56; N, 7.00.
were added to
a 10-mL round bottom flask
containing 1.0 mL [bmim][BF4] and 0.05 mmol
CeCl3 · 7H2O. Then, the mixture was stirred at 55◦C
for about 3 h to complete the reaction (monitored
by TLC). Without isolating the intermediate prod-
uct, aromatic aldehyde (1, 0.5 mmol) and another
0.5 mmol of 2 were added to the reaction mixture
and let it being stirred for about another 3 h at the
temperature of 100◦C. Upon completion, the reac-
tion mixture was added with water and the solid was
collected by suction and rinsed with water and ether.
Then, the solid obtained was further purified by re-
crystallization from 95% ethanol to give the pure
products 4. All the products were fully characterized
by 1H NMR, IR, and elemental analysis. The aqueous
solution of ionic liquid together with the catalyst was
concentrated under the reduced pressure and dried
at 100◦C to recover the ionic liquid and catalyst for
the subsequent use.
3,3,6,6-Tetramethyl-9-(3-nitrophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4e). 294–
1
296◦C (lit. [10a] 285–286◦C). H NMR (CDCl3, 400
MHz) δ: 0.97 (s, 6H, 2×CH3), 1.09 (s, 6H, 2×CH3),
2.13–2.43 (m, 8H, 4×CH2), 5.16 (s, 1H, CH), 6.14
(s, 1H, NH), 7.37 (t, J = 8.0 Hz, 1H, ArH), 7.86 (d,
J = 8.0 Hz, 1H, ArH), 7.94 (d, J = 8.0 Hz, 1H, ArH),
8.02 (s, 1H, ArH); IR (KBr): 3444 (NH), 1648 (C O),
1609 (N C C) cm−1.
3,3,6,6-Tetramethyl-9-(2-nitrophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4f). 293–
1
295◦C. H NMR (CDCl3, 400 MHz) δ: 0.97 (s, 6H,
2×CH3), 1.07 (s, 6H, 2×CH3), 2.10–2.31 (m, 8H,
4×CH2), 5.72 (s, 1H, CH), 6.48 (s, 1H, NH), 7.19 (t,
J = 8.0 Hz, 1H, ArH), 7.41 (t, J = 8.0 Hz, 1H, ArH),
7.53 (d, J = 8.0 Hz, 1H, ArH), 7.65 (d, J = 8.0 Hz, 1H,
ArH); 13C NMR (CDCl3, 300 MHz) δ: 27.56, 28.99,
31.83, 32.51, 41.22, 50.61, 112.67, 124.16, 126.72,
131.68, 131.93, 135.32, 140.07, 148.35, 195.17; IR
(KBr): 3439 (NH), 1635 (C O), 1595 (N C C)
cm−1; MS (70 eV) m/z: 394 (M+); Anal. Calcd. for
C23H26N2O4: C, 70.03; H, 6.64; N, 7.10. Found: C,
70.18; H, 6.58; N, 7.05.
3,3,6,6-Tetramethyl-9-(4-chlorophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4a). 298–
1
300◦C (lit. [10c] 296–298◦C). H NMR (CDCl3, 400
MHz) δ: 0.94 (s, 6H, 2×CH3), 1.06 (s, 6H, 2×CH3),
2.12–2.31 (m, 8H, 4×CH2), 5.05 (s, 1H, CH), 7.14 (d,
J = 8.0 Hz, 2H, ArH), 7.27 (d, J = 8.0 Hz, 2H, ArH),
7.73 (s, 1H, NH); IR (KBr): 3433 (NH), 1650 (C O),
1610 (N C C) cm−1.
3,3,6,6-Tetramethyl-9-phenyl-3,4,5,6,9,10-hexa-
hydroacridine-1,8(2H,7H)-dione (4b). 258–260◦C
3,3,6,6-Tetramethyl-9-(4-bromophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4g). 312–
315◦C. 1H NMR(CDCl3, 400 MHz) δ: 0.95 (s, 6H,
2×CH3), 1.07 (s, 6H, 2×CH3), 2.12–2.35 (m, 8H,
4×CH2), 5.03 (s, 1H, CH), 6.95 (s, 1H, NH), 7.20 (d,
J = 8.0 Hz, 2H, ArH), 7.30 (d, J = 8.0 Hz, 2H, ArH);
13C NMR(CDCl3, 300 MHz) δ: 27.13, 29.49, 32.66,
33.42, 41.01, 50.70, 113.18, 119.77, 129.88, 131.00,
145.51, 148.11, 195.47; IR (KBr): 3444 (NH), 1647
(C O), 1610 (N C C) cm−1; MS (70 eV) m/z: 429
(M+ + 2), 427 (M+); Anal. Calcd. for C23H26BrNO2:
C, 64.49; H, 6.12; N, 3.27. Found: C, 64.52; H, 6.28;
N, 3.05.
1
(lit. [9] 250–252◦C). H NMR (CDCl3, 400 MHz) δ:
0.97 (s, 6H, 2×CH3), 1.08 (s, 6H, 2×CH3), 2.14–2.35
(m, 8H, 4×CH2), 5.11 (s, 1H, CH), 7.08 (t, J = 8.0
Hz, 1H, ArH), 7.20 (t, J = 8.0 Hz, 2H, ArH), 7.35 (d,
J = 8.0 Hz, 2H, ArH), 7.55 (s, 1H, NH); IR (KBr):
3439 (NH), 1640 (C O), 1606 (N C C) cm−1.
3,3,6,6-Tetramethyl-9-(4-methylphenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4c). 318–
320◦C (lit. [18] > 300◦C). 1H NMR (CDCl3, 400
MHz) δ: 0.94 (s, 6H, 2×CH3), 1.04 (s, 6H, 2×CH3),
2.11–2.29 (m, 11H, 4×CH2, CH3), 5.04 (s, 1H, CH),
6.97 (d, J = 8.0 Hz, 2H, ArH), 7.21 (d, J = 8.0 Hz,
2H, ArH), 7.99 (s, 1H, NH); IR (KBr): 3443 (NH),
1651 (C O), 1607 (N C C) cm−1.
3,3,6,6-Tetramethyl-9-(2-bromophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione
(4h).
1
>300◦C(decompose). H NMR (CDCl3, 400 MHz) δ:
0.99 (s, 6H, 2×CH3), 1.07 (s, 6H, 2×CH3), 2.10–2.36
(m, 8H, 4×CH2), 5.31 (s, 1H, CH), 6.23 (s, 1H, NH),
6.92 (t, J = 8.0 Hz, 1H, ArH), 7.15 (t, J = 8.0 Hz, 1H,
3,3,6,6-Tetramethyl-9-(4-nitrophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4d). 288–
1
289◦C. H NMR (CDCl3, 400 MHz) δ: 0.95 (s, 6H,
Heteroatom Chemistry DOI 10.1002/hc

790 Fan et al.
ArH), 7.42 (d, J = 8.0 Hz, 2H, ArH);13C NMR(CDCl3,
300 MHz) δ: 27.46, 29.33, 32.48, 36.27, 41.36, 50.66,
112.89, 123.31, 126.67, 127.46, 132.83, 133.31,
144.34, 147.65, 195.17; IR (KBr): 3433 (NH), 1650
(C O), 1612 (N C C) cm−1; MS (70 eV) m/z: 429
(M+ + 2), 427 (M+); Anal. Calcd for C23H26BrNO2: C,
64.51; H, 6.12; N, 3.27. Found: C, 64.49; H, 6.22; N,
3.03.
[3] Timpe, H. J.; Ulrich, S.; Ali, S. J Photochem Photo-
biol, A Chem 1991, 61, 77–89.
[4] Timpe, H. J.; Ulrich, S.; Fouassier, J. P. J Photochem
Photobiol 1993, 73, 139–150.
[5] Timpe, H. J.; Ulrich, S.; Decker, C.; Fouassier, J. P.
Macromolecules 1993, 26, 4560–4566.
[6] Janis, R. A.; Silver, P. J.; Triggle, D. J. Adv Drug Res
1987, 16, 309.
[7] Vo, D.; Matowe, W. C.; Ramesh, M.; Iqbal, N.;
Wolowyk, M. W.; Howlett, S. E.; Knaus, E. E. J Med
Chem 1995, 38, 2851–2859.
[8] Loev, B.; Snader, K. M. J Org Chem 1965, 30, 1914–
1916.
[9] Srividya, N.; Ramamurthy, P.; Shanmugasundaram,
P.; Ramakrishnan, V. T. J Org Chem 1996, 61, 5083–
5089.
[10] (a) Suarez, M.; Loupy, A.; Salfran, E.; Moran, L.;
Rolando, E. Heterocycles 1999, 51, 21–27; (b) Tu, S.;
Miao, C.; Gao,Y.; Fang, F.; Zhuang, Q.; Feng, Y.; Shi,
D. Synlett 2004, 2, 255–258; (c) Tu, S.; Gao,Y.; Miao,
C.; Li, T.; Zhang, X.; Zhu, S.; Fang, F.; Shi, D. Synth
Commun 2004, 34, 1289–1294; (d) Tu, S.; Lu, Z.; Shi,
D.; Yao, C.; Gao, Y.; Guo, C. Synth Commun 2002,
32, 2181–2185.
[11] Dupont, J.; De Souza, R. F.; Suarez, P. A. Z. Chem
Rev 2002, 102, 3667–3691.
[12] (a) Welton, T. Chem Rev 1999, 99, 2071–2083;
(b) Wasserscheid, P.; Keim, W. Angew Chem, Int Ed
2000, 39, 3773–3789; (c) Earle, M. J.; Seddon, K. R.
Pure Appl Chem 2000, 72, 1391–1398.
3,3,6,6-Tetramethyl-9-(2-chlorophenyl)-3,4,5,6,9,
10-hexahydroacridine-1,8(2H,7H)-dione (4i). 220–
1
222◦C (lit. [10d] 221–223◦C). H NMR (CDCl3, 400
MHz) δ: 0.98 (s, 6H, 2×CH3), 1.07 (s, 6H, 2×CH3),
2.10–2.38 (m, 8H, 4×CH2), 5.30 (s, 1H, CH), 6.36
(s, 1H, NH), 7.01 (t, J = 8.0 Hz, 1H, ArH), 7.12 (t,
J = 8.0 Hz, 1H, ArH), 7.20 (d, J = 8.0 Hz, 1H, ArH),
7.50 (d, J = 8.0 Hz, 1H, ArH); IR (KBr): 3436 (NH),
1637 (C O), 1609 (N C C) cm−1.
3,3,6,6-Tetramethyl-9-(4-hydroxy,3-methoxyphen-
yl)-3,4,5,6,9,10-hexahydroacridine-1,8(2H,7H)-dione
(4j). 294–295◦C. 1H NMR (CDCl3, 400 MHz) δ: 0.98
(s, 6H, 2×CH3), 1.08 (s, 6H, 2×CH3), 2.19–2.39 (m,
8H, 4×CH2), 3.87 (s, 3H, OCH3), 4.98 (s, 1H, CH),
5.38 (s, 1H, NH), 5.73 (s, 1H, OH), 6.62 (d, J = 8.0
Hz, 1H, ArH), 6.69 (d, J = 8.0 Hz, 1H, ArH), 7.05
(s, 1H, ArH); 13C NMR (CDCl3, 300 MHz) δ: 27.21,
29.48, 32.71, 33.12, 41.47, 50.73, 55.90, 112.06,
113.76, 114.20, 119.73, 125.07, 138.80, 145.99,
146.55, 195.20; IR (KBr): 3423 (NH), 1660 (C O),
1625 (N C C) cm−1; MS (70 eV) m/z: 395 (M+);
Anal. Calcd for C24H29NO4: C, 72.89; H, 7.39; N,
3.54. Found: C, 72.78; H, 7.48; N, 3.50.
[13] (a) Sheldon, R. Chem Commun 2001, 2399–2407;
(b) Le Boulaire,V.; Gree, R. Chem Commun 2000,
2195–2196.
[14] (a) Bartoli, G.; Bosco, M.; Foglia, G.; Giuliani,
A.; Marcantoni, E.; Sambri, L. Synthesis 2004, 6,
895–900; (b) Bartoli, G.; Bosco, M.; Giuliani, A.;
Marcantoni, E.; Palmieri, A.; Petrini, M.; Sambri, L.
J Org Chem 2004, 69, 1290–1297; (c) Bose, D. S.;
Fatima, L.; Mereyala, H. B. J Org Chem 2003, 68, 587–
590; (d) Ankala, S. V.; Fenteany, G. Tetrahedron Lett
2002, 43, 4729–4732; (e) Mase, N.; Nishi, T.; Hiyoshi,
M.; Ichihara, K.; Bessho, J.; Yoda, H.; Takabe, K. J
Chem Soc, Perkin Trans 1 2002, (6), 707–709.
[15] Imamoto, T. Lanthanides in Organic Synthesis; Aca-
demic Press: New York, 1994.
REFERENCES
[1] Prabahar, K. J.; Ramakrishnan, V. T.; Sastikumar,
D.; Selladurai, S.; Masilamani, V. Indian J Pure Appl
Phys 1991, 29, 382–384.
[2] Shanmugasundaram, P.; Murugan, P.; Ramakrish-
nan, V. T.; Srividya, N.; Ramamurthy, P. Heteroat
Chem 1996, 7, 17–22.
[16] Xie, Y. Y.; Chen, Z. C.; Zheng, Q. G. Synthesis 2002,
1505–1508.
[17] Holbrey, J. D.; Seddon, K. R. J Chem Soc, Dalton
Trans 1999, 2133–2139.
[18] Wang, X. S.; Shi, D. Q.; Zhang, Y. F.; Wang, S. H.; Tu,
S. J. Chin J Org Chem 2004, 24, 430–432.
Heteroatom Chemistry DOI 10.1002/hc