Convenient, mild and one-pot synthesis of double Schiff bases from three component reaction of salicylaldehyde, ammonium acetate and aliphatic aldehydes accelerated by NEt3 as a base

Article abstract of DOI:10.1002/jccs.200700182

A convenient and efficient procedure for one-pot preparation of double Schiff bases through a three component reaction of salicylaldehyde, ammonium acetate and aliphatic aldehyde was described. In this reaction, N,N′-bis(salicylidene)-1,1-diaminoalkanes w

Full text of DOI:10.1002/jccs.200700182

Journal of the Chinese Chemical Society, 2007, 54, 1293-1298
1293
Convenient, Mild and One-Pot Synthesis of Double Schiff Bases from
Three Component Reaction of Salicylaldehyde, Ammonium Acetate and
Aliphatic Aldehydes Accelerated by NEt3 as a Base
Hossein Naeimi* and Khadigeh Rabiei
Department of Chemistry, Faculty of Sciences, University of Kashan, Kashan 87317, I.R. Iran
A convenient and efficient procedure for one-pot preparation of double Schiff bases through a three
component reaction of salicylaldehyde, ammonium acetate and aliphatic aldehyde was described. In this
reaction, N,N¢-bis(salicylidene)-1,1-diaminoalkanes was easily obtained in excellent yields and short re-
action times under mild reaction condition.
Keywords: Schiff base; Salicylaldehyde; Three component; One pot; Aldehydes.
INTRODUCTION
Combinatorial chemistry is widely used in pharma-
Also these complexes find many important catalytic appli-
cations, ranging from asymmetric epoxidations,13-16 reduc-
tion of aromatic ketones,17 and asymmetric aziridination of
olefins18 to various types of polymerization19-22 as well as
their widespread use for preparation of the ion selective
electrodes,23-28 solid phase extraction of metal ions,29 etc.
Schiff base compounds containing an imine group are
usually formed by the condensation of primary amine and
diamine with an active carbonyl compound in methanol
solvent.30 In solvent medium the reactants can interact ef-
fectively if they are in a homogenous solution, whereby the
reactant molecules come together rapidly and continually.
Moreover uniform heating or cooling of the mixture, if
needed, can be carried out in solution relatively easily. It
could be deeply and inseparably associated with the pro-
cess of an organic reaction through the solvation of the re-
actants, products, transition state or other intervening spe-
cies. Such intimate interactions between the solvent and the
reaction partners are due to many factors that include elec-
trostatic, steric and conformational effects among others.31
In continuation of our current efforts on research, we
are focused on the development of the multicomponent re-
action and the utilization of these processes toward the
synthesis of double Schiff bases. In this study, we report a
practical and efficient three component reaction by which
N,N¢-bis(salicylidene)-1,1-diaminoalkanes were synthe-
sized by reacting the salicylaldehyde, ammonium salt and
aliphatic aldehyde in the presence of a base at room temper-
ature (Scheme I).
ceutical research as a powerful tool for acceleration of the
identification of novel therapeutic agents in drug discov-
ery. In this field, multicomponent condensation reactions
have been utilized very efficiently in conjugation with
combinatorial chemistry to prepare large collections of
molecules in a short reaction sequence.1 Multicomponent
reactions (MCR) are an attractive concept for high-through-
put chemistry that provide the ability to rapidly generate
new complex products from simple substrates.2-4
The history of MCR dates back to 1838 when Laurent
and Gerhardt prepared benzoylazotid.5 MCR, defined as
one-pot reactions in which at least three functional groups
join through covalent bonds, have been steadily gaining
importance in synthetic organic chemistry.6 The reagents
employed may be different molecules or they may be dif-
ferent functional groups of the same reagent. Speed, diver-
sity, efficiency and environmental amiability are some of
the key features of this class of reactions.7 In times where a
premium is put on speed, diversity and efficiency in the
drug discovery process MCR strategies offer significant
advantages over conventional liner-type syntheses.8,9
Schiff base ligands have gained importance because
of the physiological and pharmacological activities associ-
ated with them. They constitute an interesting class of che-
lating agents capable of coordination with metal ions given
complex which serve as models for biological system.10-12
* Corresponding author. Fax: +98-361-5552935; E-mail: naeimi@kashanu.ac.ir

1294 J. Chin. Chem. Soc., Vol. 54, No. 5, 2007
Naeimi and Rabiei
Scheme I
Table 1. The reaction of salicylaldehyde and propionaldehyde
with various ammonium salts at room temperature
RESULTS AND DISCUSSION
Entry
Ammonium Salt
Time/hour
Yield/%
The first time, the salicylaldehyde, ammonium ace-
tate salt and propionaldehyde were reacted together in ratio
2:2:1, respectively, by stirring at room temperature in a
methanol solution (Scheme I).
1
2
3
4
5
6
7
8
NH4OAc
NH4OOCPh
NH4NO3
2
2.5
4
40
30
17
15
10
-
NH4Cl
4
In this research, we were interested in studing various
ammonium salts in the reaction. The results have been
summarized in Table 1. As shown in this Table, ammonium
acetate and ammonium benzoate were the most effective
among the other ammonium salts in this reaction (entries 1
and 2 in Table 1). The reason for this behavior may be due
to the usage of later pointed salts where strong acids were
yielded in the reaction mixture that can be inefficient for
progress of the reaction. When the reaction was done by us-
ing (NH4)2C2O4, no product was obtained even with an ex-
tension of the reaction time to several days (entry 6, Table
1).
NH4SCN
7
(NH4)2C2O4
(NH4)2SO4
(NH4)6Mo7O24
72
6
5
5
15
Table 2. Preparation of Schiff base in the presence of various
bases at room temperature
Entry
Base
Time/min
Yielda/%
1
2
3
4
5
6
7
NaOOCCH3
NaHCO3
KOH
80
70
55
60
90
90
95
45
40
50
NaOH
50
When the above mentioned reaction was performed
in the presence of a base, the reaction was remarkably en-
hanced, giving an excellent yield of the desired product.
With respect to these results, we infer that the base may
play a main role in the reaction. Thus the reaction of salic-
ylaldehyde, propionaldehyde and NH4OAc has been car-
ried out in the presence of various bases at room tempera-
ture. Table 2 introduces the results of these investigations.
As can be seen in Table 2, by using the NEt3, KOH
and NaOH as a base, the reaction proceeded faster than the
reaction either with other bases or without any base (com-
pare entries 3, 4 and 5 vs 1, 2, 6 and 7 in Table 2).
NEt3
45
Pyridine
None
115
120
a Isolated yield based on salicylaldehyde.
that reaction, and it can be powerful enough to change the
reaction course itself. Thus in conjunction with this re-
search, the reaction of salicylaldehyde, propionaldehyde
and ammonium acetate has been considered in the presence
of NEt3 as a base in various solvents (Scheme II). The re-
sults are indicated in Table 3. As shown in this Table, these
three component reactions proceeded with speed in order
as follows: MeOH, EtOH > DMSO > DMF > CH3CN >
THF, CHCl3, CH2Cl2.
Nothing that a solvent has the power to enhance or re-
duce the speed of a reaction, at times enormously, the
changing of a solvent of a reaction can influence the rate of
Scheme II

One-Pot Synthesis of Double Schiff Bases
J. Chin. Chem. Soc., Vol. 54, No. 5, 2007 1295
nal around the d = 4.6-5.0 ppm is assigned to the protons of
the NCHN. The UV spectra show about 2-3 maximum ab-
sorptions dependent on the particular structure of the com-
pound.
Table 3. Schiff base formation in various solvents at room
temperature
Entry
Solvent
Time/min
Yielda/%
1
2
3
4
5
6
7
8
MeOH
EtOH
45
45
40
40
80
70
90
90
95
95
92
95
10
10
5
DMF
DMSO
THF
CONCLUSION
CH3CN
CHCl3
CH2Cl2
In this study, we have shown that the NEt3 base dra-
matically accelerates the rates of one-pot preparation of
double Schiff base compounds. This method was carried
out by a three-component reaction of two aldehydes and
ammonium acetate at room temperature. The excellent
yields of useful Schiff base products were successfully
achieved in a short time with this mild, efficient and conve-
nient method.
5
a Isolated product yield.
This sequence can probably be related to the polarity
and ability of these solvents for hydrogen bonding forma-
tion with the transition state and intermediate of this reac-
tion that can be influenced to dissolve and hamper their sta-
bility.
Finally, in order to elucidate the generality of this
one-pot reaction, we employed several aliphatic aldehydes
in the reaction with salicylaldehyde and ammonium acetate
in the presence of NEt3 base in ethanol solvent at room tem-
perature (Scheme III).
EXPERIMENTAL
Chemicals were purchased from the Merck Chemical
Company in high purity. IR spectra were recorded as KBr
pellets on a Perkin-Elmer 781 Spectrophotometer and an
1
The results of these reactions are shown in Table 4. As
indicated in the Table, a lot of useful double Schiff bases
were afforded in excellent yields and short reaction times
from the one-pot reaction of various aldehydes with salic-
ylaldehyde and ammonium acetate.
Impact 400 Nickolet FTIR Spectrophotometer. H NMR
spectra were recorded in CDCl3 with (400 MHz) Spectrom-
eter using TMS as an internal reference. Melting points ob-
tained with a Yanagimoto micromelting point apparatus are
uncorrected. The purity determination of the substrates and
reactions monitoring were accomplished by TLC on sil-
ica-gel polygram SILG/UV 254 plates.
The structures of the products have been assigned by
spectroscopic data. In the IR spectra, the characteristic
Schiff base C=N stretching frequency is formed in the re-
gion between u =1600-1700 cm-1 as a signal strong band.
The OH stretching frequency is found at u = 3000 cm-1 with
a particular width. The stretching vibration of C-H in the
alkyl groups appear in the region between u = 2700-2800
General Procedure for Synthesis of N,N¢-bis(2-hy-
droxybenzylidene)-1,1-diaminoalkanes
To a mixture of salicylaldehyde (0.4 g, 3.27 mmol)
and propionaldehyde (R=C2H5, 0.095 g, 1.64 mmol) was
added NH4OAc (0.25 g, 3.27 mmol) in the presence of the
NEt3 (1 mL) as a base by stirring in one portion. The stir-
ring of the mixture continued for 45 minutes. The progress
of the reaction was monitored by TLC. After the comple-
1
cm-1 with sharp absorptions. In the H NMR spectra, the
broad signals with d =12-13 ppm are assigned to the pro-
tons of the hydroxyl groups. Two protons of CH=N have
the same chemical shifts in d = 8.30-8.46 ppm, and the sig-
Scheme III

1296 J. Chin. Chem. Soc., Vol. 54, No. 5, 2007
Naeimi and Rabiei
Table 4. The reaction of salicylaldehyde, ammonium acetate and different aldehydes in the presence of NEt3
at room temperature in EtOH solvent
Entry
Aliphatic Aldehyde
Time (min)
M.P. (oC)
Yield a (%)
Product
N
N
1
HCHO
45
116-118
95
OH
HO
Me
N
N
2
3
4
5
CH3CHO
30
45
45
35
98-100
92-94
72-74
82-84
92
95
94
96
OH
HO
Et
N
N
CH3CH2CHO
CH3(CH2)2CHO
CH3(CH2)3CHO
OH
HO
n-Pr
N
N
OH
HO
n-Bu
N
N
OH
HO
n-Pe
n
N
N
6
7
8
CH3(CH2)4CHO
CH3(CH2)5CHO
CH3(CH2)6CHO
35
30
25
72-74
82-84
64-66
96
95
97
OH
HO
n-Hex
N
N
OH
HO
n-Hept
N
N
OH
H3C
HO
CH3
N
N
9
(CH3)2CHCHO
20
25
74-76
98
92
OH
H3C
HO
CH3
CH2
10
(CH3)2CHCH2CHO
Oil
N
N
OH
HO
CH2
CH2
11
Ph(CH2)2CHO
40
Oil
93
N
N
OH
HO
a Isolated product yields.

One-Pot Synthesis of Double Schiff Bases
J. Chin. Chem. Soc., Vol. 54, No. 5, 2007 1297
tion of the reaction, the mixture became yellow. After cool-
ing the reaction mixture, a solid product was formed, fil-
tered off and washed with cold MeOH. The crude product
was purified by recrystallization in ethanol and the pure
Schiff base, N,N¢-bis(2-hydroxybenzylidene)-1,1-diami-
nopropane was obtained in 95% yield, m.p. = 92-94 °C.
The Schiff base products were identified by spectroscopic
data.
118.8, 119, 133, 133.7, 161. UV (CHCl3)/lmax (nm) 322
(w), 260 (s); MS: m/z = 297 (M++1, 6), 296 (M+, 7), 176
(15), 175 (100), 91 (17), 77 (45), 58 (55), 56 (30), 42 (15);
Anal. Calcd. For C. H. N.: C, 72.97; H, 6.77; N, 9.46.
Found: C, 72.98; H, 6.80; N, 9.46.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminopentane
mp 82-84 °C; IR (KBr)/u (cm-1) 3250-3430 (br, OH);
1625 (s, C=N), 1491, 1577 (Ar); 1H NMR/CDCl3/d p.p.m:
0.9 (t, 3H, CH3), 1.4 (m, 4H, 2CH2), 1.9 (q, 2H, CH2), 4.99
(t, 1H, NCHN), 6.9-7.7 (m, 8H), 8.7 (s, 2H, C=N), 12.93 (s,
2OH); 13C NMR/CDCl3/d p.p.m: 15.3, 17, 20, 82, 117, 118,
119, 133, 133.2, 165; UV (CHCl3)/lmax (nm) 320 (w), 260
(s); MS: m/z = 311 (M++1, 5), 310 (M+, 9), 190 (12), 189
(100), 91 (20), 77 (40), 58 (55), 56 (25), 42 (14); Anal.
Calcd. For C. H. N.: C, 73.55; H, 7.09; N, 9.03. Found: C,
73.56; H, 7.10; N, 9.03.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminomethane
mp 116-118 °C; IR (KBr)/u (cm-1) 3150-3450 (br,
OH); 1620 (s, C=N), 1587, 1501 (Ar); 1H NMR/CDCl3/d
p.p.m: 4.46 (s, 2H), 6.9-7.6 (m, 8H), 8.6 (s, 2H); 12.70 (s,
2OH); 13C NMR/CDCl3/d p.p.m: 85, 117.6, 119.9, 118.7,
133, 133.9, 161; MS: m/z = 243 (M++1, 7), 242 (M+, 8), 132
(14), 133 (100), 91 (17), 77 (44), 58 (60); UV (CHCl3)/lmax
(nm) 320 (w), 260 (s); Anal. Calcd. For C. H. N.: C, 69.42;
H, 5.78; N, 11.57. Found: C, 69.43; H, 5.8; N, 11.57.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminohexane
mp 72-74 °C; IR (KBr)/u (cm-1) 3000-3350 (br, OH);
1629 (s, C=N), 1486, 1573 (Ar); 1H NMR/CDCl3/d p.p.m:
0.9 (t, 3H, CH3), 1.4 (m, 6H, 3 CH2), 1.9 (q, 2H, CH2), 4.99
(t, 1H, NCHN), 6.9-7.7 (m, 8H), 8.5 (s, 2H, C=N), 13.1 (s,
2OH); 13C NMR/CDCl3/d p.p.m: 12.3, 19, 21, 86, 118, 119,
120.5, 133, 133.2, 166; UV (CHCl3)/lmax (nm) 320 (w),
261 (s); MS: m/z = 325 (M+ + 1, 3), 324 (M+, 5), 202 (20),
175 (100), 91 (15), 77 (35), 58 (58), 42 (25); Anal. Calcd.
For C. H. N.: C, 74.07; H, 7.40; N, 8.64. Found: C, 74.08;
H, 7.41; N, 8.65.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminoethane
mp = 98-100 °C; IR (neat)/u (cm-1) 3000-3300 (br,
OH); 1625 (s, C=N), 1490.6, 1576 (Ar); 1H NMR/CDCl3/d
p.p.m: 2.5 (d, 3H, CH3), 4.5 (q, 1H, NCHN), 6.9-7.6 (m,
8H), 8.7 (s, 2H, C=N), 13.02 (s, 2OH); 13C NMR/CDCl3/d
p.p.m: 25.4, 84.2, 117.4, 119.4, 118.7, 132.9, 133, 161.3,
166; UV (CHCl3)/lmax (nm) 323 (w), 262 (s); MS: m/z =
269 (M++1, 6), 298 (M+, 10), 149 (100), 91 (20), 77 (30), 58
(55); Anal. Calcd. For C. H. N.: C, 71.64; H, 5.95; N, 10.45.
Found: C, 71.64; H, 5.97; N, 10.45.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminopropane
mp 92-94 °C; IR (KBr)/u (cm-1): 3150-3450 (br, OH),
1625 (s, C=N), 1501, 1587 (Ar); 1H NMR/CDCl3/d p.p.m:
4.8 (t, 1H, NCHN), 0.9 (t, 3H, CH3), 1.99 (m, 2H, CH2),
6.9-7.6 (m, 8H), 8.7 (s, 2H, C=N); 13.0 (s, 2OH); 13C
NMR/CDCl3/d p.p.m: 19, 20.2, 85, 116.4, 118.4, 119.6,
133, 133.7, 161.3; MS: m/z = 283 (M+ + 1, 6%), 282 (M+,
10), 162 (13), 161 (100), 91 (20), 77 (45), 58 (59); UV
(CHCl3)/lmax (nm); Anal. Calcd. For C. H. N.: C, 72.34; H,
6.38; N, 9.93. Found: C, 72.35; H, 6.39; N, 9.93.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminoheptane
mp 82-84 °C; IR (KBr)/u (cm-1) 3250-3500 (br, OH),
1631 (s, C=N), 1491, 1571 (Ar); 1H NMR/CDCl3/d p.p.m:
0.8 (t, 3H, CH3), 1.3 (m, 8H, 4CH2), 1.9 (q, 2H, CH2), 5.0 (t,
1H, NCHN), 6.9-7.6 (m, 8H), 8.7 (s, 2H, C=N), 13.2 (s,
2OH); MS: m/z = 339 (M+ + 1, 10%), 338 (M+, 15), 220
(20), 220 (100), 91 (29), 77 (50), 58 (57), 56 (34), 42 (20);
UV (CHCl3)/lmax (nm) 320 (w), 262 (s); Anal. Calcd. For
C. H. N.: C, 74.55; H, 7.69; N, 8.28. Found: C, 74.56; H,
7.7; N, 8.28.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminobutane
mp 72-74 °C; IR (KBr)/u (cm-1) 3100-3440 (br, OH);
1625 (s, C=N), 1502, 1576 (Ar); 1H NMR/CDCl3/d p.p.m:
0.9 (t, 3H, CH3), 1.4 (m, 2H, CH2), 1.9 (q, 2H, CH2), 4.99 (t,
1H, NCHN), 6.9-7.7 (m, 8H), 8.7 (s, 2H, C=N), 13.0 (s,
2OH); 13C NMR/CDCl3/d p.p.m: 15.3, 18, 20, 84, 117.4,
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminoctane
mp 64-66 °C; IR (KBr)/u (cm-1) 3300-3500 (br, OH),
1630 (s, C=N), 1491, 1571 (Ar); 1H NMR/CDCl3/d p.p.m:
0.89 (t, 3H, CH3), 1.34 (m, 10H, 5 CH2), 1.93 (m, 2H, CH2),
4.89 (t, 1H, NCHN), 6.9-7.56 (m, 8H), 8.7 (s, 2H, C=N),
12.4 (s, 2OH). UV (CHCl3)/lmax (nm) 320 (w), 262 (s).

1298 J. Chin. Chem. Soc., Vol. 54, No. 5, 2007
Naeimi and Rabiei
7. Nair, V.; Ragest, C.; Vinod, A. V.; Bindu, S.; Sreekanth, A.
R.; Mathen, J. S.; Balagopal, L. Acc. Chem. Res. 2003, 36,
899.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diaminoisobutane
mp 74-76 °C; IR (KBr)/u (cm-1) 3250-3520 (br, OH);
1615 (s, C=N), 1502, 1577 (Ar); 1H NMR/CDCl3/d p.p.m:
0.8 (d, 6H, CH3), 2.0 (m, 1H, CH), 4.4 (t, 1H, NCHN),
6.9-7.2 (m, 8H), 8.2 (s, 2H, C=N), 12.9 (s, 2OH); 13C
NMR/CDCl3/d p.p.m: 18.4, 35.2, 92, 117.4, 119.4, 119.7,
133, 133.7, 161.3; UV (CHCl3)/lmax (nm) 323 (w), 242 (w),
262 (s); MS: m/z = 297 (M+ + 1, 5), 296 (M+, 6), 177 (12),
176 (100), 133 (11), 132 (58), 91 (18), 77 (42), 58 (58);
Anal. Calcd. For C. H. N.: C, 72.97; H, 6.76; N, 9.45.
Found: C, 72.97; H, 6.76; N, 9.45.
8. Schreiber, S. L. Science 2000, 287, 1964.
9. Dolle, R. E.; Nelson, K. H. J. Comb. Chem. 1999, 1, 235.
10. Wilkinson, G. Comprehensive Coordination Chemistry;
Pergamon Press: New York, 1987; pp 4-6, pp 166-167, pp
494-495, p 634, p 639, p 687.
11. Hang, P. H.; Keck, J. G.; Lein, E. J.; Mclai, M. J. Med. Chem.
1990, 33, 608.
12. Tai, A. E.; Lein, E. J.; Mclai, M.; Khwaja, T. A. J. Med.
Chem. 1984, 27, 236.
13. (a) Rukhsana, I. K.; Noor-ui, H. K.; Sayed, H. R. Tetrahe-
dron Asymmetry 1993, 4, 1693. (b) Samsel, E. G.; Srinivasan,
K.; Kochi, J. K. J. Am. Chem. Soc. 1985, 107, 7606.
14. Zhang, W.; Loebach, J. L.; Wilson, S. R.; Jacobsen, E. N. J.
Am. Chem. Soc. 1990, 112, 2801.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diamino-3-phenyl-
propane
Oil; IR (neat)/u (cm-1) 3000-3300 (br, OH), 1625 (s,
C=N), 1490.6, 1576 (Ar); 1H NMR/CDCl3/d p.p.m: 0.9 (d,
6H, CH3), 1.4 (m, 1H, CH2), 1.9 (2H, CH2), 4.99 (t, 1H,
NCHN), 6.9-7.7 (m, 13H), 8.7 (s, 2H, C=N), 13.02 (s,
2OH); UV (CHCl3)/lmax (nm) 323 (w), 262 (s), 243 (sh).
15. Irie, R.; Noda, K.; Ito, Y.; Matsumoto, N.; Katsuki, T. Tetra-
hedron Lett. 1990, 31, 7345.
16. (a) Frandez, I.; Pedro, J. R.; Salud, R. Tetrahedron, 1996, 52,
1201. (b) Sigman, M. S.; Jacobsen, E. N . J. Am. Chem. Soc.
1998, 120, 4901.
17. Kim, G. J. H. Catal. Lett. 1999, 63, 83.
N,N¢-bis(2-hydroxybenzylidene)-1,1-diamino-3-methyl-
butane
18. Kenneth, J. O.; Shiow, J. W.; Cynthia, J. B. Tetrahedron Lett.
1992, 33, 1001.
Oil; IR (neat)/u (cm-1) 3300-3555 (br, OH), 1625 (s,
C=N), 1490, 1577 (Ar); 1H NMR/CDCl3/d p.p.m: 0.8 (d,
6H, CH3), 2.0 (m, 1H, CH), 1.5 (t, 2H, CH2), 4.4 (t, 1H,
NCHN), 6.9-7.4 (m, 8H), 8.2 (s, 2H, C=N), 12.9 (s, 2OH);
UV (CHCl3)/lmax (nm) 323 (w), 262 (s), 252 (sh).
19. Younkin, T. R.; Connor, E. F.; Henderson, J. I.; Friedrich, S.
K.; Grubbs, R. H.; Bansleben, D. A. Science 2000, 287, 460.
20. Satio, J.; Mitani, M.; Matsui, S.; Mohri, J.; Kojoh, S.;
Kashiwa, N.; Fujita, T. Angew. Chem. Int. Ed. 2001, 40,
2918.
21. Jones, D. J.; Gibson, V. C.; Green, S. M.; Maddox, P. J.
Chem. Commun. 2002, 10, 1038.
22. O’Reilly, R. K.; Gibson, V. C.; White, A. J. P.; Williams, D. J.
J. Am. Chem. Soc, 2003, 125, 8450.
ACKNOWLEDGEMENT
23. Shamsipur, M.; Sadeghi, S.; Naeimi, H.; Sharghi, H. Polish.
J. Chem. 2000, 74, 231.
We are grateful to The University of Kashan Research
Council for partial support of this work.
24. Alizadeh, N.; Ershad, S.; Naeimi, H.; Sharghi, H.; Shamsipur,
M. Fresenius J. Anal. Chem. 1999, 365, 511.
25. Mazlum-Ardakany, M.; Ensafi, A. A.; Naeimi, H.; Dastanpour,
A.; Shamelli, A. Sens. Actuators, B 2003, 441.
26. Khorrami, A. R.; Naeimi, H.; Fakhari, A. R. Talanta, 2004,
64, 13.
Received November 27, 2006.
27. Shamsipur, M.; Yousefi, M.; Hosseini, M.; Ganjali, M. R.;
Sharghi, H.; Naeimi, H. Anal. Chem. 2001, 73, 2869.
28. Shamsipur, M.; Saeidi, M.; Yari, A.; Yaganeh-Faal, A.;
Mashhadizadeh, M. H.; Azimi, G.; Naeimi, H.; Sharghi, H.
Bull. Korean. Chem. Soc. 2004, 25, 629.
REFERENCES
1. Gedey, S.; Eycken, J. V. D.; Flop, F. Org. Lett. 2002, 4, 1967.
2. Biginelli, P. Ber. 1891, 24, 1317.
29. Shamsipur, M.; Ghiasvand, A. R.; Sharghi, H.; Naeimi, H.
Anal. Chim. Acta 2000, 271.
3. Mannich, C.; Krosche, W. Arch. Pharm. 1912, 250, 647.
4. Vgi, I. Angew. Chem. Int. Ed. Engle. 1962, 1, 8.
5. Lauren, A.; Gerhardt, C. F. Liebigs Ann. Chem. 1838, 38,
265.
30. Santos, J. E.; Edward, R. D. E.; Cavalheiro, T. G. Carbohydr.
Polym. 2005, 60, 277-282.
31. Nagendrappa, G. Resonance 2002, 59.
6. Domling, A.; Vgi, I. Angew. Chem. Int. Ed. 2000, 39, 3168.