Preparation of N-arylsulfonyl imines from sulfonamides and aryl aldehydes using magnesium oxide as a heterogeneous and reusable catalyst under solvent-free conditions

Article abstract of DOI:10.1080/10426500802002802

An efficient solvent-free procedure for the preparation of N-arylsulfonyl imines from sulfonamides and aryl aldehydes in the presence of a catalytic amount of magnesium oxide and tetrabutylammonium bromide (TBAB) under microwave irradiation is described. The advantages of this method are good to high yields, short reaction times, low cost, and matching with green chemistry protocols. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500802002802

This article was downloaded by: [University of Sydney]
On: 08 August 2013, At: 03:04
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Phosphorus, Sulfur, and Silicon
and the Related Elements
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gpss20
Preparation of N-Arylsulfonyl
Imines from Sulfonamides
and Aryl Aldehydes Using
Magnesium Oxide as a
Heterogeneous and Reusable
Catalyst Under Solvent-Free
Conditions
Alireza Hasaninejad a , Abdolkarim Zare b , Ahmad
Reza Moosavi Zare c , Abolfath Parhami c , Hashem
Sharghi c & Ali Khalafi-Nezhad c
a Department of Chemistry, Faculty of Sciences,
Persian Gulf University, Bushehr, Iran
b Department of Chemistry, Payame Nour University
(PNU), Iran
c Department of Chemistry, College of Sciences,
Shiraz University, Shiraz, Iran
Published online: 07 Oct 2008.
To cite this article: Alireza Hasaninejad , Abdolkarim Zare , Ahmad Reza Moosavi
Zare , Abolfath Parhami , Hashem Sharghi & Ali Khalafi-Nezhad (2008) Preparation of
N-Arylsulfonyl Imines from Sulfonamides and Aryl Aldehydes Using Magnesium Oxide
as a Heterogeneous and Reusable Catalyst Under Solvent-Free Conditions, Phosphorus,
Sulfur, and Silicon and the Related Elements, 183:11, 2769-2776
To link to this article: http://dx.doi.org/10.1080/10426500802002802
PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the
information (the “Content”) contained in the publications on our platform.
However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness,
or suitability for any purpose of the Content. Any opinions and views
expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the
Content should not be relied upon and should be independently verified with
primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages,
and other liabilities whatsoever or howsoever caused arising directly or
indirectly in connection with, in relation to or arising out of the use of the
Content.
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden. Terms & Conditions of access and use can be found at
http://www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur, and Silicon, 183:2769–2776, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500802002802
Preparation of N-Arylsulfonyl Imines from Sulfonamides
and Aryl Aldehydes Using Magnesium Oxide as a
Heterogeneous and Reusable Catalyst Under
Solvent-Free Conditions
Alireza Hasaninejad,1 Abdolkarim Zare,2 Ahmad Reza
Moosavi Zare,3 Abolfath Parhami,3 Hashem Sharghi,3
and Ali Khalafi-Nezhad3
1Department of Chemistry, Faculty of Sciences, Persian Gulf University,
Bushehr, Iran
2Department of Chemistry, Payame Nour University (PNU), Iran
3Department of Chemistry, College of Sciences, Shiraz University,
Shiraz, Iran
An efficient solvent-free procedure for the preparation of N-arylsulfonyl imines from
sulfonamides and aryl aldehydes in the presence of a catalytic amount of magne-
sium oxide and tetrabutylammonium bromide (TBAB) under microwave irradi-
ation is described. The advantages of this method are good to high yields, short
reaction times, low cost, and matching with green chemistry protocols.
Keywords Aldehyde; magnesium oxide; microwave; N-arylsulfonyl imine; solvent-free;
sulfonamide
INTRODUCTION
N-Sulfonyl imines are versatile intermediates in organic synthesis.1
They are excellent substrates in aza Diels-Alder reactions,2 nucleophilic
additions3 and reductions,4 as well as in radical5 or ene reactions.6
They have been also used in the synthesis of aziridines.7 Several syn-
thetic methods for the preparation of N-sulfonyl imines have been re-
ported so far.8−21 Most of them involve the condensation of sulfonamides
Received 25 November 2007; accepted 19 February 2008.
We thank the Persian Gulf University, the Payame Nour University, and the Shiraz
University Research Councils for financial support of this work.
Address correspondence to Alireza Hasaninejad, Department of Chemistry, Faculty
of Sciences, Persian Gulf University, Bushehr 75169, Iran. E-mail: ahassaninejad@
yahoo.com or Abdolkarim Zare, Department of Chemistry, Payame Noor University
(PNU), Iran. E-mail: abdolkarimzare@yahoo.com
2769

2770
A. Hasaninejad et al.
with aldehydes in the presence of strong Lewis acids. In many cases,
strongly acidic conditions are not compatible with other functionalities
present in a given substrate. Some methods need two-steps procedures
or they are expensive methods and generate toxic byproducts. Moreover,
some methods require the preparation of the starting materials such as
oxime, sulfinylimine and/or aziridine.13,14,17 Because of the limitations
of the above methods, development of a new method for the synthe-
sis of N-sulfonyl imines under basic conditions in one step would be
desirable.
Recently, mineral oxides have proved to be useful to chemists in
the laboratory as well as in industry due to the effective activation
of adsorbed compounds and the enhancement of reaction rate, selectiv-
ity, easier workup, recyclability of the supports and the eco-friendly
reaction conditions.22 Magnesium oxide is one of these oxides: it is
inexpensive, reusable, commercially available and an environmen-
tally benign catalyst. Magnesium oxide has been extensively studied
as a promising catalyst,23 modifier, or promoter,24 and catalyst sup-
port in several transformations such as Michael addition and Knoeve-
nagel condensation,25 transformation of ethanol to butanol26 and self-
condensation of propanol.27
Solvent-free organic reactions have been applied as a useful protocol
in organic synthesis.Solvent-free reactions under thermal or microwave
conditions often lead to shorter reaction times, increased yields, and
easier workup. They match with green chemistry protocols and may
enhance the regio- and stereoselectivity of reactions.28
Considering the above aspects, and along with our previous work
on the synthesis of N-sulfonyl imines published in this journal,9 as
well as in extension of our previous studies on solvent-free organic
syntheses,22a,29 we report here a clean, facile and rapid method for
the preparation of N-arylsulfonyl imines from sulfonamides and aryl
aldehydes in the presence of a catalytic amount of magnesium oxide
and tetrabutylammonium bromide (TBAB) under microwave irradia-
tion (Scheme 1).
SCHEME 1

Preparation of N-Arylsulfonyl Imines Using Magnesium Oxide as a Catalyst 2771
TABLE I The Influence of Various Basic Catalysts on the
Reaction of Benzenesulfonamide with Benzaldehyde in the
Presence of TBAB Under Microwave Irradiation (300 W,
max. 110◦C)
Catalyst
Time (min)
Yielda (%)
MgO
CaO
8
8
8
8
8
12
12
12
87
74
61
68
53
65
57
60
Cs2CO3
K2CO3
t-BuOK
DABCO
NBu3
1-Methyl-imidazole
aIsolated yield.
RESULTS AND DISCUSSION
To determine the optimal reaction conditions we have studied the reac-
tion of benzenesulfonamide with benzaldehyde as a model reaction to
provide compound 1 (Scheme 1 and Table I). At first, the effect of var-
ious basic catalysts was examined to evaluate their capabilities. The
results are summarized in Table I. As shown in Table I higher yields
and shorter reaction times were achieved when MgO was used. There-
fore, MgO was chosen as catalyst for all the other reactions.
In order to select the appropriate microwave power the model re-
action was examined at different microwave powers (100–600 W) with
controlled temperature (max. 110◦C) in the presence of MgO and TBAB.
The best results were observed at 300 W of microwave power.
In another study, the role of TBAB was evaluated. The absence of
TBAB in the reaction medium afforded low yields even when the reac-
tion time or the microwave power was increased. Thus, the presence of
TBAB in the reaction mixture is critically significant. TBAB absorbs the
microwave irradiation, generates in situ heat and increases the temper-
ature above its melting point (100–103◦C). In addition TBAB creates a
homogeneous medium similar to that of an ionic liquid.28a
To investigate the versatility, as well as the capacity of our method,
the reaction of sulfonamides with various structurally diverse aromatic
aldehydes were examined (Table II). As indicated in Table II, the reac-
tions proceeded efficiently and the N-arylsulfonyl imines were obtained
in good to high yields in short reaction times.
It has been observed that the electronic properties of the aromatic
ring of aldehydes affected the reaction. The results showed that halogen

2772
A. Hasaninejad et al.
TABLE II Preparation of N-Arylsulfonyl Imines from Sulfonamides
and Aldehydes in the Presence of Catalytic Amounts of MgO and
TBAB Under Microwave Irradiation (300 W, max. 110◦C)
Time
(min)
Yielda
(%)
Aldehyde
Product
M. p. (Lit.)
77–80 (78–81)[18]
8
87
64
123–124 (125–126)[8]
205–207 (208–209)[19]
206–207 (209–210)[11]
130–132 (131–132)[20]
113–114 (111)[11]
15
12
15
12
15
15
12
20
15
15
20
15
15
85
79
84
62
56
80
60
77
78
54
76
75
164–165 (162–164)[21]
108–109 (109)[16]
126–128 (126–128)[9]
172–173 (172–173)[8]
181–183 (182–185)[18]
88–90 (91–92)[16]
112–114 (111–112)[8]
118–120 (121–123)[18]

Preparation of N-Arylsulfonyl Imines Using Magnesium Oxide as a Catalyst 2773
TABLE II Preparation of N-Arylsulfonyl Imines from Sulfonamides
and Aldehydes in the Presence of Catalytic Amounts of MgO and
TBAB Under Microwave Irradiation (300 W, max. 110◦C)
(Continued)
Time
(min)
Yielda
(%)
Aldehyde
Product
M. p. (Lit.)
111–114 (114–117)[18]
17
15
20
20
71
73
57
59
126–128 (128–129)[8]
102–104 (101–102)[8]
172–173 (172–173)[9]
aIsolated yield.
atoms as well as electron-donating substituents had no significant
effect on the yields (Table II). However, aryl aldehydes possessing
electron-withdrawing or sterically demanding substituents generally
need longer reaction times, and the yields are lower (Table II). It should
be mentioned that the yield of N-arylsulfonyl imines resulting from the
reaction of benzenesulfonamide with aldehydes was higher than that
starting from 4-methyl benzenesulfonamide.
The interesting behavior of magnesium oxide lies in the fact that it
can be reused after simple washing with ethyl acetate, thus rendering
the process more economic. The yields of compound 1 (model compound)
when MgO was used for the 2nd, 3rd, 4th, and 5th time were almost as
high as when it was used for the first time.
In conclusion, the procedure presented here provides a clean, rapid
and efficient solvent-free route to N-arylsulfonyl imines via the reaction
of sulfonamides with aryl aldehydes using cheap and safe reagents.
EXPERIMENTAL
All chemicals were obtained from Merck or Fluka. The compounds were
identified by the comparison of their melting points and/or 1H and 13
C
NMR data with those of authentic samples. All reactions were carried
out using a CEM MARS 5TM microwave oven. The 1H (250 MHz) and 13
(62.5 MHz) NMR spectra were obtained with a Bruker Avance DPX-250
C

2774
A. Hasaninejad et al.
spectrometer. Melting points were recorded with a Bu¨chi B-545 appa-
ratus in open capillary tubes and are uncorrected.
General Procedure for the Preparation of N-Arylsulfonyl
Imines from Sulfonamides and Aryl Aldehydes Under
Solvent-Free Conditions
To a well ground mixture of the sulfonamide (2 mmol), MgO (0.020 g,
0.5 mmol) and TBAB (0.129 g, 0.4 mmol) in a microwave vessel was
added the respective aldehyde (2.6 mmol),30 and the compounds were
carefully mixed with a tiny spatula. The mixture was irradiated in the
microwave oven at 300 W for the times reported in Table II. The mi-
crowave oven was programmed to give a maximum internal tempera-
ture to 110◦C. The reaction mixture was cooled to room temperature,
suspended in ethyl acetate (50 mL), filtered, and the filtrate was washed
with water (2 × 50 mL) and dried over MgSO4.The filtrate was concen-
trated to 5 mL, n-hexane (20–30 mL) was added, and the solution was
allowed to stand at room temperature for 5–6 h. During this time crys-
tals formed, which were collected by filtration, washed with n-hexane
(20 mL) and dried.
REFERENCES
[1] (a) S. M. Weinreb, Top. Curr. Chem., 190, 131 (1997); (b) M. Gohain, Synlett, 2097
(2003); (c) R. Bloch, Chem. Rev., 98, 1407 (1998).
[2] (a) J. Sisko and S. M. Weinreb, Tetrahedron Lett., 30, 3037 (1989); (b) D. L. Boger,
W. L. Corbett, T. T. Curran, and A. M. Kasper, J. Am. Chem. Soc., 113, 1713 (1991);
(c) O. Garcia-Mancheno, R. Gomez-Arrayas, and J. C. Carretero, J. Am. Chem. Soc.,
126, 456 (2004) and references cited therein.
[3] (a) M. J. Melnick, A. J. Freyes, and S. M. Weinreb, Tetrahedron Lett., 29, 3891 (1988);
(b) K. Yamada, H. Fujihara, Y. Yamamoto, Y. Miwa, T. Taba, and K. Tomioka, Org.
Lett., 3509 (2002); (c) V. Aggarwal, E. Alonso, M. Ferrar, and S. E. Spey, J. Org. Chem.,
67, 2335 (2002); (d) T. Soeta, K. Nagai, H. Fujihara, M. Kuriyama, and K. Tomioka,
J. Org. Chem., 68, 9723 (2003); (e) P. Wipf, C. Kendall, and C. R. Stephenson, J. Am.
Chem. Soc., 125, 761 (2003); (f) M. Gunter and H.-J. Gais, J. Org. Chem., 68, 8037
(2003). (g) H. -K. Yim and H. N. C. Wong, J. Org. Chem., 69, 2892 (2004).
[4] (a) M. Hojo, C. Murakami, A. Fujii, and A. Hosomi, Tetrahedron Lett., 40, 911 (1999);
(b) H. Nisikori, R. Yoshihara, and A. Hosomi, Synlett, 561 (2003).
[5] K. -I. Yamada, H. Fujihara, Y. Yamamoto, Y. Miwa, T. Taga, and K. Tomioka, Org.
Lett., 3509 (2002).
[6] M. Yamanaka, A. Nishida, and M. Nakagwa, Org. Lett., 159 (2002).
[7] (a) R. Hori, T. Aoayama, and T. Shoiri, Tetrahedron Lett., 41, 9455 (2000); (b) L. G.
Arini, A. Sinclair, P. Szeto, and R. A. Stockan, Tetrahedron Lett., 45, 1589 (2004).
[8] B. M. Trost and M. Christopher, J. Org. Chem., 56, 6468 (1991).
[9] A. Hasaninejad and H. Sharghi, Phosphorus, Sulfur, and Silicon, 182, 873 (2007).

Preparation of N-Arylsulfonyl Imines Using Magnesium Oxide as a Catalyst 2775
[10] K. Y. Lee, C. G. Lee, and J. N. Kim, Tetrahedron Lett., 44, 1231 (2003) and references
cited therein.
[11] E. Zieglere and W. Ruef, Z. Naturforsch., 30B, 946 (1975).
[12] G. D. Artman, A. Bartolozzi, R. W. Franck, and S. M. Weinreb, Synlett, 232 (2001).
[13] D. L. Boger and W. L. Corbett, J. Org. Chem., 57, 4777 (1992).
[14] J. Wolfe and J. E. Ney, Org. Lett., 5, 4607 (2003).
[15] (a) W. B. Jennings and C. J. Lovely, Tetrahedron, 47, 5561 (1991); (b) G. I. Georg, G.
C. B. Harriman, and S. A. Peterson, J. Org. Chem., 60, 7366 (1995); (c) R. N. Ram
and A. A. Khan, Synth. Commun., 31, 841 (2001); (d) T. Jin, G. Feng, M. Yang, and
T. Li, Synth. Commun., 34, 1277 (2004).
[16] F. A. Davis, J. Lamendola, U. Nadir, E. W. Kluger, T. C. Sedergran, T. W. Panunto,
R. Billmers, R. Jenkins, I. J. Turchi, W. H. Watson, J. S. Chen, and M. Kimura, J.
Am. Chem. Soc., 102, 2000 (1980).
[17] J. L. G. Ruano, J. Aleman, M. Belen Cid, and A. Parra, Org. Lett., 179 (2005).
[18] A. Vass, J. Dudas, and R. S. Varma, Tetrahedron Lett., 40, 4951 (1999).
[19] V. I. Naddaka, K. V. Avanesyan, M. L. Cherkinskaya, and V. I. Minkin, Zh. Org.
Khim., 24, 603 (1988).
[20] Z. I. Kuplennik, Z. N. Belaya, and A. M. Pinchuk, Zh. Obshch. Khim., 51, 2711
(1981).
[21] F. A. Davis and S. G. La, J. Org. Chem., 53, 5004 (1988).
[22] (a) A. Zare, A. Hasaninejad, A. Khalafi-Nezhad, A. R. Moosavi Zare, A. Parhami,
and G. R. Nejabat, Arkivoc, i, 58 (2007); (b) M. Hosseini Sarvari and H. Sharghi,
Tetrahedron, 61, 10903 (2005); (c) M. Hosseini Sarvari, Synthesis, 787 (2005); (d) M.
Hosseini Sarvari and H. Sharghi, J. Org. Chem., 69, 6953 (2004); (e) Y. J. Kim and
R. S. Varma, Tetrahedron Lett., 45, 7205 (2004); (f) R. S. Varma, Tetrahedron, 58,
1235 (2002); (g) H. Sharghi and M. Hosseini, Synthesis, 1057 (2002); (h) M. Gupta,
S. Paul, R. Gupta, and A. Loupy, Tetrahedron Lett., 46, 4957 (2005); (i) F. Tamaddon,
M. A. Amrollahi, and L. Sharafat, Tetrahedron Lett., 46, 7841 (2005).
[23] M. A. Aramendia, V. Borau, C. Jime´nez, J. M. Marinas, J. R. Ruiz, and F. J. Urbano,
Appl. Catal. A, 207 (2003).
[24] P. Kovacheva, K. Arishtirova, and S. Vassilev, Appl. Catal. A, 3915 (2001).
[25] C. Xu, J. K. Bartley, D. I. Enache, D. W. Knight, and G. J. Hutchings, Synthesis, 3468
(2005).
[26] A. S. Ndou, N. Plint, and N. J. Coville, Appl. Catal. A, 337 (2003).
[27] A. S. Ndou and N. J. Coville, Appl. Catal. A, 103 (2004).
[28] (a) A. Loupy, Microwave in Organic Synthesis, Wiley-VCH, Weinheim, 2004; (b)
K. Tanaka, Solvent-free Organic Synthesis, (Wiley-VCH, Weinheim, 2004); (c) R.
S. Varma, Advances in Green Chemistry: Chemical Synthesis Using Microwave Ir-
radiation, Astra Zeneca Research Foundation, Kavitha Printers: Bangalore, India,
2002; (d) A. Shockravi, H. Shargi, H. Valizadeh, and M. M. Heravi, Phosphorus,
Sulfur, and Silicon, 177, 2555 (2002); (e) A. Ramazani, L. Yousefi, E. Ahmadi, and
A. Souldozi, Phosphorus, Sulfur, and Silicon, 179, 1459 (2004); (f) M. Zolfigol, F.
Shirini, K. Zamani, E. Ghofrani, and S. Ebrahimi, Phosphorus, Sulfur, and Silicon,
179, 2177 (2004); (g) X. Wang, J. Liu, and Z. Li, Phosphorus, Sulfur and Silicon, 181,
627 (2006); (h) M. Zolfigol, P. Salehi, and M. Shiri, Phosphorus, Sulfur and Silicon,
179, 2273 (2004); (i) A. Javidan and A. Banan, Phosphorus, Sulfur, and Silicon, 179,
2253 (2004); (j) A. Shaabani, A. Bazgir, and S. Arab-Ameri, Phosphorus, Sulfur, and
Silicon, 179, 2169 (2004); (k) A. Khalafi-Nezhad, A. Zare, A. Parhami, M. N. Soltani
Rad, and G. R. Nejabat, Can. J. Chem., 84, 979 (2006).
[29] (a) A. Khalafi-Nezhad, A. Zare, A. Parhami, M. N. Soltani Rad, and G. R. Nejabat,
Phosphorus, Sulfur, and Silicon, 182, 657 (2007); (b) A. Khalafi-Nezhad, A. Zare,

2776
A. Hasaninejad et al.
A. Parhami, M. N. Soltani Rad, and G. Reza Nejabat, Synth. Commun., 36, 3549
(2006); (c) A. Khalafi-Nezhad, A. Zare, M. N. Soltani Rad, A. Mokhtari, and A.
Parhami, Synthesis, 419 (2005); (d) A. Khalafi-Nezhad, A. Parhami, M. N. Soltani
Rad, and A. Zarea, Tetrahedron Lett., 46, 6879 (2005); (e) A. Khalafi-Nezhad, M.
N. Soltani Rad, and A. Khoshnood, Synthesis, 583 (2004); (f) A. Khalafi-Nezhad, B.
Mokhtari, and M. N. Soltani Rad, Tetrahedron Lett., 44, 7325 (2003); (g) A. Khalafi-
Nezhad, M. N. Soltani Rad, and G. H. Hakimelahi, Helv. Chim. Acta, 86, 2396
(2003); (h) A. Khalafi-Nezhad and A. Hashemi, Iran. J. Chem. Chem. Eng., 20,
9 (2001); (i) A. Khalafi-Nezhad, F. Alamdari, and N. Zekri, Tetrahedron, 56, 7503
(2000); (j) A. Khalafi-Nezhad and A. Hashemi, J. Chem. Res. (S), 720 (1999).
[30] In the case of solid aldehydes, they were thoroughly ground with the other reactants
to give a homogeneous mixture.