InCl3-catalyzed efficient synthesis of spiro-perimidine derivatives

Article abstract of DOI:10.1016/j.crci.2010.02.002

InCl₃ was found to be a mild and effective catalyst for the simple and efficient synthesis of spiro-perimidine derivatives by the reaction of naphthalene-1,8-diamine and active carbonyl compounds in water at room temperature. This protocol incl

Full text of DOI:10.1016/j.crci.2010.02.002

C. R. Chimie 13 (2010) 1308–1312
Contents lists available at ScienceDirect
Comptes Rendus Chimie
www.sciencedirect.com
´
Full paper / Memoire
InCl3-catalyzed efficient synthesis of spiro-perimidine derivatives
*
Zahra Yasaei, Peiman Mirzaei, Ayoob Bazgir
Department of Chemistry, Shahid Beheshti University, G.C, PO Box 19396, 4716 Tehran, Iran
A R T I C L E I N F O
Article history:
A B S T R A C T
Received 12 August 2009
Accepted after revision 5 February 2010
InCl3 was found to be a mild and effective catalyst for the simple and efficient synthesis of
Available online 19 March 2010
spiro-perimidine derivatives by the reaction of naphthalene-1,8-diamine and active
carbonyl compounds in water at room temperature. This protocol includes some
important aspects like the use of water as a ‘‘green’’ reaction medium, good yielding of
products and mild reaction conditions.
Keywords:
InCl3
Naphthalene-1,8-diamine
Perimidine
´
ß 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Active carbonyl compound
1. Introduction
synthesis of 2-methyl-2-aryl-2,3-dihydro-1H-perimidines
using naphthalene-1,8-diamine with aromatic ketones in
Spirocyclic systems containing one carbon atom com-
mon to two rings are structurally interesting [1,2]. The
presence of the sterically constrained spiro structure in
various natural products also adds to the interest in the
investigations of spiro compounds [3]. Spiro compounds
represent an important class of naturally occurring sub-
stances characterised by their highly pronounced biological
properties [4,5]. Perimidines (peri-naphtho-fused pyrimi-
dine systems) are an important class of heterocyclic
compounds, since many of this heterocyclic system exhibit
biological and pharmaceutical activity [6]. The interest in
pyrido-fused perimidine derivatives stems from the ap-
pearance of these heterocyclic systems in many biologically
active compounds [6,7]. Considering the important biolo-
gical properties of perimidines, a number of methods have
been reported for the synthesis of these heterocycles [6–10].
However, the preparation of perimidine derivatives using
naphthalene-1,8-diamine with ketones has not been much
developed. To our knowledge, in several methods, protonic
acids have been used for this transformation as catalysts
[11]. However, their strong acidity led to the occurrence of
side reactions and substrates. Reddy and Rao reported
acetic acid or methanol with moderate product yields (60 %)
[11c]. The methods of acid-catalyzed reactions are not very
efficient. Therefore, there is a need for a new efficient
catalyst for this organic transformation. Very recently,
synthesis of perimidine derivatives has been reported
using catalytic amounts of BiCl3 [12], RuCl3 [13] and
Yb(OTf)3 [14].
In recent years, indium (III) chloride (InCl3) has received
considerable attention as an inexpensive, non-toxic,
readily available catalyst for various transformations
under mild and convenient conditions, affording the
corresponding products in excellent yields with high
selectivity [15].
Due to the biological activity of perimidine derivatives,
and our interest in the synthesis of heterocyclic com-
pounds [16–31], herein, we report a simple and efficient
method for the preparation of spiro-perimidines in water.
In fact, as clearly stated by Sheldon [32], it is generally
recognized that ‘‘the best solvent is no solvent and if a
solvent (diluent) is needed it should preferably be water’’.
The use of water as the reaction medium represents a
remarkable benefit since this green solvent is highly polar
and therefore immiscible with most organic compounds;
moreover, the water soluble catalyst resides and operates
in the aqueous phase and separation of the organic
materials is thus easy.
* Corresponding author.
E-mail address: a_bazgir@sbu.ac.ir (A. Bazgir).
1631-0748/$ – see front matter ß 2010 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.crci.2010.02.002

Z. Yasaei et al. / C. R. Chimie 13 (2010) 1308–1312
1309
2. Results and discussion
To achieve suitable catalyst and solvent for the
synthesis of spiro-perimidines, various solvent and
catalysts have been investigated in the reaction of
naphthalene-1,8-diamine 1 and isatin 2a as a model
reaction at room temperature (Fig. 4). As could be seen in
Fig. 4, the best result was obtained with a 20 mol % of
InCl3 as the catalyst in water at room temperature (Fig. 4).
Using a lower amount of catalyst resulted in lower yields,
while a higher amount of catalyst did not affect reaction
times and yields (Fig. 4). When this reaction was carried
out without any catalyst, TLC and 1H NMR spectra of the
Fig. 1. .
reaction mixture showed
a combination of starting
materials and numerous products, the yield of the
expected product was very poor (Fig. 4, entry 5). Fig. 4
demonstrates that water was the best choice of solvent
and the use of InCl3 in water improved the yield of the
product.
Encouraged by this success, we extended the reaction of
naphthalene-1,8-diamine
1 with various isatins 2a-h
under similar conditions (H2O/InCl3), furnishing the
respective spiro[indoline-3,20-perimidin]-2-ones 3a-h in
good yields. The optimized results are summarized in
Fig. 5.
Table 1 compares efficiency of InCl3 (time, yield,
reaction conditions) with the efficiency of other catalysts
in the synthesis of perimidine derivatives obtained by
other catalysts. It is clear from Fig. 5 that InCl3 is
comparable to the catalysts used previously for the
synthesis of perimidines.
Fig. 2. .
As expected, when the isatin 2 was replaced by
acenaphthylene-1,2-dione 4, 10,30-dihydro-2H-spiro[ace-
naphthylene-1,20-perimidin]-2-one 5 was obtained in 78 %
yield under the same reaction conditions (Fig. 1).
To further explore the potential of this protocol for
perimidines synthesis, we investigated reaction of
naphthalene-1,8-diamine 1 with 2-indanone 6 or pyrimi-
dine-tetraone
7 and obtained tetrahydrospiroindene-
perimidine 8 and 1,3-dihydro-10H-spiro[perimidine-2,50-
pyrimidine]-20,40,60(30H)-trione
9
in excellent yields
(Fig. 2).
When the piperidin-4-one 10, cyclododecanone 11 and
11H-indeno[2,1-b]quinoxalin-11-one 12 was selected as
active carbonyl compounds (Fig. 3), the desired spiro-
perimidines 13, 14 and 15 were obtained in good yields.
When this reaction was carried out with ninhydrine 16,
benzoquinone 17 and naphthoquinone 18 in same condi-
tions (H2O/InCl3), TLC and 1H NMR spectra of the reaction
mixture showed a combination of starting materials and
numerous products, the yield of the expected product was
very poor.
Fig. 3. .
Table 1
Comparison of efficiency of various catalysts in synthesis of perimidines.
Catalyst
Conditions
Yield (%)
Time (h)
Ref.
InCl3
H2O/r.t.
EtOH/r.t
EtOH/r.t
EtOH/r.t
77–91
79–92
78–91
75–93
3–4
This work
[12]
BiCl3
0.5–12
0.5–24
0.5–32
RuCl3
Yb(OTf)3
[13]
[14]
Fig. 4. Effect of reaction conditions.

1310
Z. Yasaei et al. / C. R. Chimie 13 (2010) 1308–1312
7.34 (11H, m, H-Ar and 2NH), 10.24 (1H, s, NH). 13C NMR
(75 MHz, DMSO-d6): = 67.9, 105.4, 110.1, 111.8, 116.0,
d
122.3, 125.7, 127.2, 130.2, 130.8, 133.9, 141.0, 143.0, 177.9.
MS, m/z: 367 (M+), 365 (M+). Analytically calculated for
C
18H12BrN3O: C 59.03; H 3.30; N 11.47 %. Found: C 59.9;
H 3.24; N 11.40 %.
4.2.3. 5-Nitro-10,30-dihydrospiro[indoline-3,20-perimidin]-2-
one 3c
Fig. 5. Synthesis of spiro[indoline-3,20-perimidin]-2-ones 3.
Light brown powder; m.p. 263 8C (dec). IR (KBr): 3345,
3054, 2917, 1745, 1624/cm. 1H NMR (300 MHz, DMSO-d6):
All synthesized compounds are stable solids whose
structures are fully supported by IR, 1H and 13C NMR
spectroscopy, mass spectrometry, and elemental analysis.
d
= 6.47–8.33 (11H, m, H-Ar and 2NH), 11.02 (1H, s, NH).
13C NMR (75 MHz, DMSO-d6):
d
= 67.7, 106.0, 110.6, 111.8,
116.7, 120.9, 127.3, 127.9, 131.1, 133.9, 140.1, 142.6, 149.6,
178.0. MS, m/z: 332 (M+). Analytically calculated for
C
18H12N4O3: C 65.06; H 3.64; N 16.86 %. Found: C 65.15;
3. Conclusions
H 3.71; N 16.93 %.
In conclusion, InCl3 has been found to be an efficient
catalyst for the preparation of spiro-perimidine derivatives
via a cyclo-condensation reaction in water. This protocol
includes some important aspects like the use of water as a
‘‘green’’ reaction medium, high atom economy and mild
reaction conditions.
4.2.4. 1-Methyl-10,30-dihydrospiro[indoline-3,20-perimidin]-
2-one 3d
Light pink powder; m.p. 281 8C (dec). IR (KBr): 3356,
3069, 2917, 1705, 1603/cm. 1H NMR (300 MHz, DMSO-d6):
d
= 3.10 (3H, s, CH3), 6.43–7.46 (12H, m, H-Ar and 2NH).
13C NMR (75 MHz, DMSO-d6):
d
= 26.1, 67.8, 105.5, 109.0,
111.8, 116.1, 123.0, 125.3, 127.2, 129.5, 130.9, 133.9, 140.8,
144.4, 175.9. MS, m/z: 301 (M+). Analytically calculated for
C19H15N3O: C 75.73; H 5.02; N 13.94 %. Found: C 75.62;
H 5.07; N 13.86 %.
4. Experimental
4.1. Materials and techniques
Melting points were taken on an Electro-
thermal 9100 apparatus and left uncorrected. IR spectra
were obtained on a Shimadzu IR-470 spectrometer. 1H and
13C NMR spectra were recorded on a BRUKER DRX-
300 AVANCE spectrometer at 300.13 and 75.47 MHz. NMR
spectra were obtained on solutions in DMSO using TMS as
internal standard. All of the chemicals were purchased from
Fluka, Merck and Aldrich and used without purification.
4.2.5. 1-Ethyl-10,30-dihydrospiro[indoline-3,20-perimidin]-2-
one 3e
Brown powder; m.p. 250–252 8C. IR (KBr): 3374, 3048,
1707, 1598/cm. 1H NMR (300 MHz, DMSO-d6):
d
= 1.15
(3H, bs, CH3), 3.60 (2H, bs, CH2), 6.43–7.44 (12H, m, H-Ar
and 2NH). 13C NMR (75 MHz, DMSO-d6):
= 12.9, 34.2,
d
67.7, 105.5, 109.1, 111.8, 116.1, 122.8, 125.5, 127.2, 129.7,
130.9, 133.9, 140.9, 143.5, 175.5. MS, m/z: 315 (M+).
Analytically calculated for C20H17N3O: C 76.17; H 5.43;
N 13.32 %. Found: C 76.10; H 5.38; N 13.41 %.
4.2. General procedure for the preparation of spiro-
perimidines
A mixture of naphthalene-1,8-diamine (1 mmol), active
carbonyl compounds (1 mmol) and InCl3 (20 mol %) in
water (5 ml) was stirred at room temperature for
appropriate time (the progress of reaction was monitored
by TLC). After completion of the reaction, the reaction
mixture was filtered and the precipitate washed with
water and then ether to afford the pure product.
4.2.6. 1-Benzyl-10,30-dihydrospiro[indoline-3,20-perimidin]-
2-one 3f
Dark pink powder; m.p. 168 8C. IR (KBr): 3332, 1750,
1682, 1587/cm. 1H NMR (300 MHz, DMSO-d6):
d
= 4.79
(2H, s, CH2), 6.47–7.35 (17H, m, H-Ar and 2NH). 13C NMR
(75 MHz, DMSO-d6): = 42.8, 67.8, 105.6, 109.7, 111.8,
d
116.2, 123.1, 125.6, 127.2, 127.7, 129.0, 129.5, 130.8, 133.9,
136.5, 140.8, 143.5, 176.0. MS, m/z: 377 (M+). Analytically
calculated for C25H19N3O: C 79.55; H 5.07; N 11.13 %.
Found: C 79.66; H 5.14; N 11.08 %.
4.2.1. 10,30-Dihydrospiro[indoline-3,20-perimidin]-2-one 3a
White powder; m.p. 244–246 8C. IR (KBr): 3361, 3211,
1722, 1597/cm. 1H NMR (300 MHz, DMSO-d6):
d = 6.44–
7.35 (12H, m, H-Ar and 2NH), 10.24 (1H, s, NH). 13C NMR
(75 MHz, DMSO-d6): 67.9, 105.5, 110.2, 111.8, 116.0, 122.3,
125.8, 127.2, 130.2, 130.8, 133.9, 141.0, 143.0, 177.9. MS, m/
z: 287 (M+). Analytically calculated for C18H13N3O: C 75.25;
H 4.56; N 14.63 %. Found: C 75.16; H 4.51; N 14.55 %.
4.2.7. 5-Bromo-1-methyl-10,30-dihydrospiro[indoline-3,20-
perimidin]-2-one 3g
Dark brown powder; m.p. 265–258 8C (dec). IR (KBr):
3343, 1693, 1603/cm. 1H NMR (300 MHz, DMSO-d6):
d
= 3.05 (3H, s, CH3), 6.42–7.64 (11H, m, H-Ar and 2NH).
13C NMR (75 MHz, DMSO-d6):
d
= 26.3, 67.8, 105.7, 111.2,
4.2.2. 5-Bromo-10,30-dihydrospiro[indoline-3,20-perimidin]-
2-one 3b
111.8, 114.6, 116.4, 126.8, 127.2, 131.8, 133.5, 133.9, 140.4,
143.7, 175.3. MS, m/z: 381 (M+), 379 (M+). Analytically
calculated for C19H14BrN3O: C 60.02; H 3.71; N 11.05 %.
Found: C 60.10; H 3.77; N 12.99 %.
Cream powder; m.p. 236 8C (dec). IR (KBr): 3362, 3047,
1723, 1599/cm. 1H NMR (300 MHz, DMSO-d6):
d = 6.43–

Z. Yasaei et al. / C. R. Chimie 13 (2010) 1308–1312
1311
4.2.8. 1-Methyl-5-nitro-10,30-dihydrospiro[indoline-3,20-
4.2.14. 10,30-dihydrospiro[cyclododecane-1,20-
perimidine] 14
Pink powder; m.p. 185 8C. IR (KBr): 3365, 3038, 2926,
1605 cmꢀ1 1H NMR (300 MHz, DMSO-d6):
= 1.35–1.60
(22H, m, 11CH2), 6.14–7.11(8H, m, H-Ar and 2NH). 13C
NMR (75 MHz, DMSO-d6): = 19.0, 22.1, 22.5, 26.0, 26.2,
perimidin]-2-one 3h
Dark yellow powder; m.p. 274 8C (dec). IR (KBr): 3347,
3043, 2927, 1728, 1605/cm. 1H NMR (300 MHz, DMSO-d6):
.
d
d
= 3.15 (3H, s, CH3), 6.46–8.43 (11H, m, H-Ar and 2NH). 13
C
NMR (75 MHz, DMSO-d6):
d
= 26.7, 67.4, 106.1, 109.5,
d
116.9, 120.3, 127.3, 128.0, 130.5, 133.6, 133.9, 140.0, 143.1,
150.6, 176.2. MS, m/z: 346 (M+). Analytically calculated for
C19H14N4O3: C 65.89; H 4.07; N 16.18 %. Found: C 65.81;
H 4.15; N 16.11 %.
33.2, 39.1, 39.4, 40.2, 40.5, 40.7, 68.5, 104.6, 112.9, 114.7,
127.4, 134.6, 141.9. MS, m/z: 322 (M+). Analytically
calculated for C22H30N2: C 81.94; H 9.38; N 8.69 %. Found:
C 81.86; H 9.43; N 8.76 %.
4.2.9. 10,30-Dihydro-2H-spiro[acenaphthylene-1,20-
perimidin]-2-one 5
4.2.15. 10,30-dihydrospiro[indeno[2,1-b]quinoxaline-11,20-
perimidine] 15
Brown powder; m.p. 279 8C (dec). IR (KBr): 3450, 3043,
2933, 1677, 1629/m. 1H NMR (300 MHz, DMSO-d6):
Brown powder; m.p. Greater than 290 8C. IR (KBr):
3369, 3033, 2917, 1598/cm. 1H NMR (300 MHz, DMSO-d6):
d
= 7.27–8.82 (14H, m, H-Ar and 2NH). MS, m/z: 322
d
= 6.42–8.11 (16H, m, H-Ar and 2NH). MS, m/z: 372 (M+).
(M+). Analytically calculated for C22H14N2O: C 81.97;
H 4.38; N 8.69 %. Found: C 81.88; H 4.31; N 8.77 %.
Due to very low solubility of the product 5, we cannot
report the 13C NMR data for this product.
Analytically calculated for C25H16N4: C 80.63; H 4.33;
N 15.03 %. Found: C 80.52; H 4.39; N 15.11 %.
Due to very low solubility of the product 15, we cannot
report the 13C NMR data for this product.
4.2.10. 1,10,3,30-Tetrahydrospiro[indene-2,20-perimidine] 8
Light pink powder; m.p. 282 8C (dec). IR (KBr): 3339,
3038, 2938, 1597/cm. 1H NMR (300 MHz, DMSO-d6):
Acknowledgements
We gratefully acknowledge financial support from the
Research Council of Shahid Beheshti University.
d
= 3.12 (4H, s, 2CH2), 6.42–7.18 (12H, m, H-Ar and 2NH).
13C NMR (75 MHz, DMSO-d6):
d
= 46.5, 74.9, 105.2, 113.0,
115.4, 125.3, 126.9, 127.4, 134.8, 140.7, 142.4. MS, m/z: 272
(M+). Analytically calculated for C19H16N2: C 83.79; H 5.92;
N 10.29 %. Found: C 83.72; H 5.86; N 10.35 %.
References
[1] M. Sannigrahi, Tetrahedron 55 (1999) 9007.
[2] C.H. Heathcock, S.L. Graham, M.C. Pirrung, F. Plavac, C.T. White, in : J.
Simon (Ed.), Spirocyclic systems. The total synthesis of natural pro-
ducts, vol. 5, John Wiley and Sons, New York, 1983, p. 264.
[3] N. Srivastav, A. Mittal, A. Kumar, J. Chem. Soc. Chem. Commun (1992)
493.
[4] D.M. James, H.B. Kunze, D.J. Faulkner, J. Nat. Prod 54 (1991) 1137.
[5] J. Kobayashi, M. Tsuda, K. Agemi, H. Shigemiri, M. Ishibashi, T. Sasaki, Y.
Mikami, Tetrahedron 47 (1991) 6617.
[6] K. Undheim, T. Benneche, in : A.R. Katritzky, C.W. Rees, E.F.V. Scriven
(Eds.), Comprehensive heterocyclic chemistry, col. 6, Pergamon, Oxford,
1996, p. 93.
[7] X. Bu, L.W. Deady, G.J. Finlay, B.C. Baguley, W.A. Denny, J. Med. Chem. 44
(2001) 2004.
4.2.11. 1,3-Dihydro-10H-spiro[perimidine-2,50-pyrimidine]-
20,40,60(30H)-trione 9
Brown powder; m.p. 201 8C (dec). IR (KBr): 3412, 3327,
2927, 1754, 1687 cmꢀ1 1H NMR (300 MHz, DMSO-d6):
.
d
= 6.78-7.59 (8H, m, H-Ar and 2NH), 9.46 (2H, bs, 2NH).
MS, m/z: 282 (M+). Analytically calculated for C14H10N4O3:
C 59.57; H 3.57; N 19.85 %. Found: C 59.50; H 3.51;
N 19.79 %.
Due to very low solubility of the product 9, we cannot
report the 13C NMR data for this product.
[8] (a) J.J. Vanden Eynde, D. Fromont, Bull. Chim. Belg 106 (1997) 393 ;
(b) J.J. Vanden Eynde, F. Delfosse, T.V. Haverbeke, Tetrahedron 51
(1995) 5813 ;
4.2.12. 1,3-Dihydrospiro[perimidine-2,40-piperidine] 13a
Light pink powder; m.p. 282 8C (dec). IR (KBr): 3364,
3206, 2938, 1599/cm. 1H NMR (300 MHz, DMSO-d6):
(c) J.J. Vanden Eynde, F. Delfosse, A. Mayence, Y.V. Haverbeke, Tetra-
hedron 51 (1995) 11 ;
(d) J.J. Vanden Eynde, A. Mayence, A. Maquestiau, E. Anders, Hetero-
cycles 37 (1994) 815 ;
d
= 1.87 (4H, bs, 2CH2), 3.26 (4H, bs, 2CH2), 6.51–7.15
(8H, m, H-Ar and 2NH), 9.13 (1H, s, NH). 13C NMR (75 MHz,
DMSO-d6): = 33.3, 48.7, 62.1, 105.1, 112.4, 115.5, 127.5,
134.5, 140.9. MS, m/z: 239 (M+). Analytically calculated for
15H17N3: C 75.28; H 7.16; N 17.56 %. Found: C 75.17;
(e) J.J. Vanden Eynde, A. Mayence, A. Maquestiau, E. Anders, Synth.
Commun 22 (1992) 3141.
[9] R. Brehme, B. Stroede, J. Prakt. Chem 329 (1987) 246.
[10] K. Honda, H. Nakanishi, A. Yabe, Bull. Chem. Soc. Jpn 56 (1983)
2338.
[11] (a) G. Sachs, Justus Liebigs Ann, Chem. 365 (1909) 162 ;
(b) U.T. Mueller-Westerhoff, B. Vance, D.I. Yoon, Tetrahedron 47
(1991) 909 ;
d
C
H 7.11; N 16.63 %.
(c) R.R. Reddy, C.V.C. Rao, Ind. J. Heterocycl. Chem 2 (1993) 199.
[12] J. Zhang, S. Zhang, Synth. Commun 37 (2007) 2615.
[13] J. Zhang, S.L. Zhang, J.M. Zhang, Chin. Chem. Lett 18 (2007) 1057.
[14] S.L. Zhang, J.M. Zhang, Chin. J. Chem 26 (2008) 185.
[15] (a) C.G. Frost, K.K.J. Chauhan, Chem. Soc. Perkin Trans. 1 (2000) 3015 ;
(b) F. Fringuelli, O. Piermatti, F. Pizzo, L. Vaccaro, Curr. Org. Chem. 7
(2003) 1661 ;
(c) C.G. Frost, J.P. Hartley, Mini-Rev. Org. Chem. 1 (2004) 1.
[16] A. Bazgir, M. Seyyedhamzeh, Z. Yasaei, P. Mirzaei, Tetrahedron Lett 48
(2007) 8790.
4.2.13. 10-Methyl-1,3-dihydrospiro[perimidine-2,40-
piperidine] 13b
Dark brown powder; m.p. 115 8C (dec). IR (KBr): 3301,
3027, 1603/cm. 1H NMR (300 MHz, DMSO-d6):
d = 1.91
(4H, bs, 2CH2), 2.28 (3H, s, CH3), 2.79 (4H, bs, 2CH2), 6.50–
7.54 (8H, m, H-Ar and 2NH). 13C NMR (75 MHz, DMSO-d6):
d
= 33.5, 42.7, 49.9, 61.5, 105.3, 112.4, 115.7, 127.3, 134.7,
140.8. MS, m/z: 253 (M+). Analytically calculated for
16H19N3: C 75.85; H 7.56; N, 16.59 %. Found: C 75.93;
H 7.64; N 16.65 %.
[17] M. Sayyafi, M. Seyyedhamzeh, H.R. Khavasi, A. Bazgir, Tetrahedron 64
(2008) 2375.
[18] M. Dabiri, H. Arvin-Nezhad, H.R. Khavasi, A. Bazgir, J. Heterocyclic
Chem 44 (2007) 1009.
C

1312
Z. Yasaei et al. / C. R. Chimie 13 (2010) 1308–1312
[19] M. Dabiri, S.C. Azimi, H. Arvin-Nezhad, A. Bazgir, Heterocycles 75
(2008) 87.
[27] M. Dabiri, S.C. Azimi, H.R. Khavasi, A. Bazgir, Tetrahedron 64 (2008)
7307.
[20] M. Dabiri, A.S. Delbari, A. Bazgir, Synlett (2007) 821.
[21] M. Dabiri, H. Arvin-Nezhad, H.R. Khavasi, A. Bazgir, Tetrahedron 63
(2007) 1770.
[22] M. Dabiri, A.S. Delbari, A. Bazgir, Heterocycles 71 (2007) 543.
[23] R. Ghahremanzadeh, G.I. Shakibaei, A. Bazgir, Synlett (2008) 1129.
[24] S. Ahadi, H.R. Khavasi, A. Bazgir, Chem. Pharm. Bull 56 (2008) 1328.
[25] M. Sayyafi, A. Abolhasani Sooreki, A. Bazgir, Chem. Pharm. Bull 56
(2008) 1289.
[28] A. Bazgir, Z. Noroozi Tisseh, P. Mirzaei, Tetrahedron Lett 49 (2008)
5165.
[29] R. Ghahremanzadeh, S. Ahadi, M. Sayyafi, A. Bazgir, Tetrahedron Lett 49
(2008) 4479.
[30] Z. Noroozi Tisseh, S.C. Azimi, P. Mirzaei, A. Bazgir, Dyes Pigments 79
(2008) 273.
[31] A. Bazgir, M. Mohammadi Khanaposhtani, A. Abolhasani Soorki, Bioorg.
Med. Chem. Lett 18 (2008) 5800.
[26] G.I. Shakibaei, H.R. Khavasi, P. Mirzaei, A. Bazgir, J. Heterocyclic Chem
45 (2008) 1481.
[32] R.A. Sheldon, J. Mol. Catal. A 107 (1996) 75.