A novel catalyst-free one-pot synthesis of some new N-(α- hydroxybenzyl)formamides by treatment of 2,2-dichloroaziridines with dimethyl sulfoxide and water under neutral conditions

Article abstract of DOI:10.1002/hlca.201100453

A novel, mild, and efficient method is reported for the preparation of new N-(α-hydroxybenzyl)formamides in excellent yields and appropriate reaction times through the reaction of 2,2-dichloroaziridines with aqueous DMSO as the O-donor under neutral condi

Full text of DOI:10.1002/hlca.201100453

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Helvetica Chimica Acta – Vol. 95 (2012)
A Novel Catalyst-Free One-Pot Synthesis of Some
New N-(a-Hydroxybenzyl)formamides by Treatment of
2,2-Dichloroaziridines with Dimethyl Sulfoxide and Water under
Neutral Conditions
by Hossein Naeimi* and Khadijeh Rabiei
Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, 87317, I. R. Iran
(phone: þ 98-361-5912388; fax: þ 98-361-5552935; e-mail: naeimi@kashanu.ac.ir)
A novel, mild, and efficient method is reported for the preparation of new N-(a-hydroxybenzyl)-
formamides in excellent yields and appropriate reaction times through the reaction of 2,2-dichloroazir-
idines with aqueous DMSO as the O-donor under neutral conditions at 70 – 858.
Introduction. – The formyl group is an important amino protecting group in peptide
synthesis [1]. Formamides have wide applications as intermediates in the preparation of
pharmaceuticals such as fluoroquinolines [2], substituted 1-aryl-1H-imidazoles [1], 1,2-
dihydroquinolines, N-bridged heterocycles, oxazolidinones, cancer chemotherapeutic
agents, and as important reagents for Vilsmeier formylation [2a][3 – 6]. They are also in
use as Lewis base catalysts in organic transformations such as allylation [7] and
hydrosilylation [8] of carbonyl compounds. In addition, the N-formyl derivatives are
useful precursors in the preparation of N-methyl compounds [9], formamidines [10],
and isocyanide [11 – 13]. Also, l-pipecolinic acid-derived 1-formyl derivatives have
been developed as new Lewis-basic organocatalysts that promote the asymmetric
reduction of N-arylketimines with trichlorosilane as the reducing agent [14]. For this
reason, numerous methods have been reported for the preparation of formamide
derivatives by N-formylation of amines [15 – 18].
Aziridines are highly reactive molecules, in part due to ring strain [19]. As a
consequence of their high reactivity, these small heterocycles play an important role in
organic chemistry and as intermediates in the synthesis of organic, pharmaceutical [20],
and natural product intermediates. Due to the widespread applications of aziridines, a
number of articles have been published about these compounds [21 – 25].
In this study, with attention to the importance and significant applications of
formamide derivatives, we elaborated a novel method for the synthesis of new N-(a-
hydroxybenzyl)formamides (¼ N-(arylhydroxymethyl)formamides) through the reac-
tion of 2,2-dichloroaziridines with DMSO/H2O at temperatures between 70 – 858, i.e.,
in the absence of an activating reagent and under neutral conditions.
Results and Discussion. – In the Scheme, the preparation of N-(a-hydroxybenzyl)-
formamide derivatives 5a – 5i from 2,2-dichloroaziridines 4a – 4i is shown. The latter
were obtained by treatment of Schiff bases 3a – 3i with dichlorocarbene [26 – 33]
ꢀ 2012 Verlag Helvetica Chimica Acta AG, Zꢁrich

Helvetica Chimica Acta – Vol. 95 (2012)
1103
generated from CHCl3 and NaOH under phase-transfer-catalysis (PTC) conditions
(CTAB ¼ cetyltrimethylammonium
bromide ¼ N,N,N-trimethylhexadecanaminium
bromide).
Hydrolysis of geminal-dihalo compounds to the corresponding carbonyl com-
pounds often employs harsh reaction conditions, such as strong acids or strong bases
[35]. This is not the case with 2,2-dichloroaziridines which are valuable precursors for
the preparation of pharmacologically active compounds such as indolinones [28],
isoquinolines [36], and N-containing building blocks such as amidines [37] and
aziridinones [38]. In contrast to their carbocyclic analogs, 2,2-dichloroaziridines
undergo facile hydrolysis and alcoholysis [32a]. Thus, we first performed this hydrolysis
with 2,2-dichloro-1,3-bis(4-chlorophenyl)aziridine (4d) as a model in DMSO/H2O at
various temperatures (see Table 1). When the reaction was carried out at 708, as the
best condition, the desired product 5d was obtained in excellent yield (Entry 5). No
product was formed at room temperature even after 72 h (Entry 7).
Scheme. Synthesis of N-(a-Hydroxybenzyl)formamide Derivatives [32a][26][34]
Table 1. Temperature Effect on the Formation of 5da)
Entry
Temperature [8]
Time [h]
Yield [%]b)
1
2
3
4
5
6
7
50
55
60
65
70
85
r.t.
14
11
7
5
3
15
30
60
85
98
98
–
3
72
a) Reaction conditions: 4d (0.01 mol), DMSO (6 ml), and H2O (1 ml). b) Yield of isolated 5d.

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Helvetica Chimica Acta – Vol. 95 (2012)
In view of the above results, conversion of different 2,2-dichloroaziridines 4 to the
corresponding N-(a-hydroxybenzyl)formamides 5 in DMSO/H2O was investigated. As
can be seen in Table 2, when 0.01 mol of 4 were treated with 6 ml of DMSO and 1 ml of
H2O at a temperature between 708 and 858, the corresponding N-(a-hydroxybenzyl)-
formamides 5 were obtained in excellent yields and appropriate reaction times.
Table 2. Synthesis of N-(Hydroxybenzyl)formamidesa)b)
Entry
R1
R2
Product
Temperature [8]
Time [h]
Yield [%]c)
1
2
3
4
5
6
7
8
9
H
H
H
Cl
H
Br
Cl
5a
5b
5c
5d
5e
5f
5g
5h
5i
80
85
85
70
70
85
70
70
85
6
5
5
3
3
4
3
3
4
90
94
92
98
98
92
96
97
90
Cl
Cl
Br
Me
Br
Me
Br
NO2
Me
Cl
NO2
a) The synthesis of the 2,2-dichloroaziridines 4 has been described in [26]. b) Reaction conditions: 2,2-
dichloroaziridine (0.01 mol), DMSO (6 ml), and H2O (1 ml). c) Yield of isolated product 5 based on
starting material 4.
The structure of the products 5 was confirmed by spectroscopic methods such as IR,
1H- and 13C-NMR, and mass spectroscopy. In the IR spectra, the stretching frequency of
aromatic C¼C bonds was observed between 1489 and 1598 cmꢀ1. The stretching
vibration of the OꢀH group appeared at 3285 – 3340 cmꢀ1, and the absorption in the
1
region between 1639 – 1659 cmꢀ1 was assigned to the formyl group. In the H-NMR
spectra, the CHꢀOH group appeared at d(H) 5.09 – 5.28. The signals at d(H) 6.99 – 8.23
were assigned to the aromatic protons. The HꢀC¼O proton was observed at d(H)
9.97 – 10.11, and the OH signal appeared at d(H) 6.40 – 6.80. In the 13C-NMR spectra,
d(C) 73.0 – 74.1 was assigned to the OꢀCꢀN group and d(C) 171.0 – 172.0 to the
HꢀC¼O group. The mass spectra (EI) of all products showed the corresponding
molecular-ion peak.
Conclusion. – A simple and efficient method for the transformation of 2,2-
dichloroaziridines into the corresponding N-(a-hydroxybenzyl)formamides was elabo-
rated. The reaction could be carried out conveniently and proceeded with excellent
yield and purity of products. To the best of our knowledge, this is the first conversion of
a 2,2-dichloroaziridine into the corresponding formamide with DMSO/H2O as the sole
reagent.

Helvetica Chimica Acta – Vol. 95 (2012)
1105
We are grateful to the University of Kashan Research Council for the partial support of this work.
Experimental Part
General. All the materials were of commercial reagent grade. The Schiff bases and 2,2-
dichloroaziridines were prepared and characterized according to our previously reported procedures
[26][39 – 41]. M.p.: Yanagimoto micro-melting-point apparatus; uncorrected. TLC: SiO2 Polygram-SIL-
G/UV 254 plates (Merck). IR Spectra: PerkinꢀElmer-781 and Impact-400-Nicolet-FTIR spectropho-
tometer; KBr pellets; ˜n in cmꢀ1 1H- and 13C-NMR Spectra: Bruker-DRX-400 spectrometer; in
.
(D6)DMSO; d in ppm rel. to Me4Si as internal standard, J in Hz. MS: Finnigan-MAT-44S instrument,
electron impact (EI) ionization, ionization voltage 70 eV; in m/z (rel. %).
Schiff Bases 3a – 3i. In a typical reaction, 2 mmol of aldehyde 1 was added to the aniline 2 (2 mmol) in
MeOH (3 ml) and mechanically stirred at r.t. (TLC monitoring). After completion of the reaction, the
crude product was purified by recrystallization from petroleum ether: pure Schiff bases 3a – 3i with good
to excellent yields. The Schiff bases were identified by spectroscopic data [39][40].
2,2-Dichloroaziridines 4a – 4i. Measured quantities of NaOH (0.08 mol, 3.2 g) and N-cetyl-N,N,N-
trimethylammonium bromide (CTAB; 0.3 g) were dissolved in 30 ml of H2O. The mixture was uniformly
agitated at 70 – 858. Then, Schiff base 3 (0.027 mol) in CHCl3 (9.5 ml, 0.08 mol) was added dropwise to
the soln. (TLC monitoring). After completion of the reaction, the aq. phase, was extracted twice by Et2O
and the combined extract dried (MgSO4) and concentrated: 2,2-dichloro-1,3-diarylaziridines 4a – 4i in
excellent yields. Pale yellow solids which were identified by physical and spectroscopic data [26][41].
N-(4-Chlorophenyl)-N-[4-(chlorophenyl)hydroxymethyl]formamide (5d): Typical Procedure. A
soln. of 2,2-dichloro-1,3-bis(4-chlorophenyl)aziridine (4d; 3.3 g, 0.01 mol) in 6 ml (0.08 mol) of DMSO
and 1 ml of H2O was heated at 708 in an oil bath (TLC monitoring). After completion of the reaction, the
mixture was poured into cold H2O (15 ml), the resulting mixture extracted with CH2Cl2 (2 ꢁ 10 ml), and
the org. layer dried (Na2SO4) and concentrated: crude 5d as a white solid. The crude product was
recrystallized from EtOH to give 5d in 98% yield in high purity. For data, see below. Formarides 5a – 5c
and 5e – 5i were prepared similarly (cf. Table 2).
N-(Hydroxyphenylmethyl)-N-phenylformamide (5a): Yield 2.045 g (90%). White solid. M.p. 120 –
1
1228. IR (KBr): 3300 (OH), 3090, 2930, 1649 (C¼O), 1509, 1590 (C¼C, Ar). H-NMR ((D6)DMSO):
5.09 (s, CHꢀOH); 6. 48 (s, OH); 6.99 – 7.56 (m, 10 arom. H); 10.01 (s, CHO). 13C-NMR ((D6)DMSO):
74.1; 121.0; 127.0; 128.0; 131.1; 132.0; 137.0; 138.1 141.1; 171.0. MS: 228 (3, [M þ 1]þ), 227 (13, Mþ), 120
(45), 107 (74), 77 (100). Anal. calc. for C14H13NO2 (227.26): C 73.99, H 5.77, N 6.16; found: C 74.08, H
5.80, N 6.18.
N-(4-Bromophenyl)-N-(hydroxyphenylmethyl)formamide (5b): Yield 2.878 g (94%). Pale yellow
solid. M.p. 135 – 1378. IR (KBr): 3307 (OH), 3088, 2930, 1659 (C¼O), 1514, 1588 (C¼C, Ar). 1H-NMR
((D6)DMSO): 5.15 (s, CHꢀOH); 6.50 (s, OH); 7.34 – 7.69 (m, 9 arom. H); 10.00 (s, CHO). 13C-NMR
((D6)DMSO): 73.0; 119.4; 122.8; 128.9; 129.0; 131.9; 132.3; 136.0; 151.0; 171.0. MS: 307 (13, Mþ (81Br)),
305 (13, Mþ (79Br)), 200 (39), 198 (39), 171 (65), 169 (65), 157 (46), 155 (46), 107 (75), 77 (100). Anal.
calc. for C14H12BrNO2 (306.17): C 54.92, H 3.95, N 4.57; found: C 55.18, H 4.06, N 4.59.
N-(4-Chlorophenyl)-N-(hydroxyphenylmethyl)formamide (5c): Yield 2.408 g (92%). White solid.
M.p. 127 – 1298. IR (KBr): 3267 (OH), 3090, 2900, 1653 (C¼O), 1599, 1492 (C¼C, Ar). 1H-NMR
((D6)DMSO): 5.08 (s, CHꢀOH); 6. 47 (s, OH); 7.33 – 7.72 (m, 9 arom. H); 10.08 (s, CHO). 13C-NMR
((D6)DMSO): 74.0; 121.8; 127.0; 128.4; 128.6; 129.0; 129.1; 137.9 141.0; 171.8. MS: 263 (6, Mþ (37Cl)), 261
(18, Mþ (35Cl)), 156 (13), 154 (35), 127 (18), 125 (55), 107 (60), 77 (100). Anal. calc. for C14H12ClNO2
(261.71): C 64.25, H 4.62, N 5.35; found: C 64.38, H 4.72, N 5.36.
N-(4-Chlorophenyl)-N-[(4-chlorophenyl)hydroxymethyl]formamide (5d): Yield 2.902 g (98%).
White solid. M.p. 138 – 1408. IR (KBr): 3285 (OH), 3090, 2900, 1639 (C¼O), 1590, 1490 (C¼C, Ar).
1H-NMR ((D6)DMSO): 5.07 (s, CHꢀOH); 6. 50 (s, OH); 7.33, 7.41, 7.52, 7.73 (2 AA’BB’, JAB ¼ 7.4, 2.9, 8
arom. H); 10.11 (s, CHO). 13C-NMR ((D6)DMSO): 73.7; 121.8; 127.7; 128.6; 128.8; 128.9; 132.7; 137.9;
140.1; 171.5. MS: 300 (3), 298 (6), 296 (10, Mþ), 156.5 (28), 154.5 (39), 143.5 (55), 141.5 (75), 127.5 (25),

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Helvetica Chimica Acta – Vol. 95 (2012)
125.5 (40), 113.5 (50), 111.5 (38), 77 (100). Anal. calc. for C14H11Cl2NO2 (296.15): C 56.78, H 3.74, N 4.72;
found: C 56.86, H 3.80, N 4.81.
N-(4-Bromophenyl)-N-[(4-chlorophenyl)hydroxymethyl]formamide (5e): Yield 3.337 g (98%).
White solid. M.p. 124 – 1268. IR (KBr): 3288 (OH), 3100, 2900, 1639 (C¼O), 1589, 1488 (C¼C, Ar).
1H-NMR ((D6)DMSO): 5.11 (s, CHꢀOH); 6. 58 (s, OH); 7.45 – 7.67 (m, 8 arom. H); 10.10 (s, CHO).
13C-NMR ((D6)DMSO): 73.7; 115.8; 122.2; 128.6; 128.8; 132.3; 132.8; 138.3; 140.1; 171.5. MS: 343 (4),
341 (15), 339 (10, Mþ), 200 (18), 198 (18), 143 (55), 141 (70), 171 (48), 169 (48), 113.5 (45), 111.5 (60), 77
(100). Anal. calc. for C14H11BrClNO2 (340.61): C 49.37, H 3.25, N 4.11; found: C 49.51, H 3.30, N 4.18.
N-[Hydroxy(4-nitrophenyl)methyl]-N-(4-methylphenyl)formamide (5f): Yield 2.634 g (92%). Yel-
low liquid. IR (KBr): 3340 (OH), 3090, 2910, 1649 (C¼O), 1520, 1595 (C¼C, Ar), 1350, 1530. 1H-NMR
((D6)DMSO): 2.21 (s, Me); 5.28 (s, CHꢀOH); 6.80 (s, OH); 7.07, 7.54, 7.79, 8.22 (2 AA’BB’, JAB ¼ 7.4, 2.9,
8 arom. H); 9.97 (s, CHO). 13C-NMR ((D6)DMSO): 21.0; 73.4; 120.5; 123.6; 127.9; 129.5; 134.0; 135.5;
147.4; 148.2; 170.5. MS: 287 (<2, [M þ 1]þ), 286 (11, Mþ),152 (85), 134 (55), 122 (60), 105 (76), 91 (100),
77 (95). Anal. calc. for C15H14N2O2 (286.29): C 62.93, H 4.93, N 9.78; found: C 71.20, H 5.59, N 11.06.
N-(4-Bromophenyl)-N-[hydroxy(4-methylphenyl)methyl]formamide (5g): Yield 3.074 g (96%).
Pale yellow solid. M.p. 155 – 1578. IR (KBr): 3285 (OH), 3090, 2910, 1642 (C¼O), 1490, 1580 (C¼C,
Ar), 1350, 1530. 1H-NMR ((D6)DMSO): 2.27 (s, Me); 5.01 (s, CHꢀOH); 6. 40 (s, OH); 7.13 – 7.69 (m, 8
arom. H); 10.05 (s, CHO). 13C-NMR ((D6)DMSO): 22.0; 73.0; 120.0; 127.0; 129.1; 130.0; 132.0; 133.0;
135.0; 141.0; 171.0. MS: 321 (12, Mþ (81Br)), 319 (12, Mþ (79Br)), 200 (40), 198 (40), 171 (60), 169 (60),
157 (46), 155 (46), 120 (70), 91 (100), 77 (85). Anal. calc. for C15H14BrNO2 (320.19): C 56.26, H 4.41, N
4.37; found: C 56.59, H 4.55, N 4.40.
N-[(4-Chlorophenyl)hydroxymethyl]-N-(4-methylphenyl)formamide (5h): Yield 2.675 g (96%).
White solid. M.p. 142 – 1448. IR (KBr): 3286 (OH), 3090, 2920, 1638 (C¼O), 1489, 1598 (C¼C, Ar).
1H-NMR ((D6)DMSO): 2.23 (s, Me); 5.09 (s, CHꢀOH); 6. 50 (s, OH); 7.07 – 7.56 (m, 8 arom. H); 9.86 (s,
CHO). 13C-NMR ((D6)DMSO): 20.9; 73.7; 120.2; 128.5; 128.8; 129.5; 132.7; 133.1; 136.2; 140.4; 171.0.
MS: 277 (6, Mþ (37Cl)), 275 (14, Mþ (35Cl)), 143 (25), 141 (60), 134 (60), 113.5 (20), 111.5 (55), 105 (45),
91 (96), 77 (100). Anal. calc. for C15H14ClNO2 (275.74): C 65.34, H 5.12, N 5.08; found: C 65.45, H 5.16, N
5.10.
N-(4-Bromophenyl)-N-[hydroxy(4-nitrophenyl)methyl]formamide (5i): Yield 3.160 g (90%). Yel-
low liquid. IR (KBr): 3289 (OH), 3100, 2900, 1649 (C¼O), 1589, 1488 (C¼C, Ar). 1H-NMR
((D6)DMSO): 5.10 (s, CHꢀOH); 6. 54 (s, OH); 6.95, 7.50, 7.71, 8.31 (2 AA’BB’, JAB ¼ 7.4, 2.9, 8 arom. H);
10.10 (s, CHO). 13C-NMR ((D6)DMSO): 75.9; 122.3; 128.9; 129.2; 129.7; 130.1; 132.1; 134.1; 143.6; 171.5.
MS: 341 (10, Mþ (81Br)), 339 (10, Mþ (79Br)), 200 (18), 198 (18), 143.5 (55), 141.5 (70), 171 (48), 169
(48), 113.5 (45), 111.5 (60), 77 (100); Anal. calc. for C14H11BrN2O4 (351.17): C 47.88, H 3.15, N 7.98;
found: C 48.10, H 3.20, N 8.03.
REFERENCES
[1] B.-C. Chen, M. S. Bednarz, R. Zhao, J. E. Sundeen, P. Chen, Z. Shen, A. P. Skoumbourdis, J. C.
Barrish, Tetrahedron Lett. 2000, 41, 5453.
[2] a) K. Kobayashi, S. Nagato, M. Kawakita, O. Morikawa, H. Konishi, Chem. Lett. 1995, 24, 575; b) A.
Jackson, O. Meth-Cohn, J. Chem. Soc., Chem. Commun. 1995, 1319.
[3] I. M. Downie, M. J. Earle, H. Heaney, K. F. Shuhaibar, Tetrahedron 1993, 49, 4015.
[4] A. Kakehi, S. Ito, S. Hayashi, T. Fujii, Bull. Chem. Soc. Jpn. 1995, 68, 3573.
[5] B. B. Lohray, S. Baskaran, B. S. Rao, B. Y. Reddy, I. N. Rao, Tetrahedron Lett. 1999, 40, 4855.
[6] G. Petit, M. Kalnins, T. Liu, E. Thomas, K. Parent, J. Org. Chem. 1961, 26, 2563.
[7] S. Kobayashi, K. Nishio, J. Org. Chem. 1994, 59, 6620.
[8] S. Kobayashi, M. Yasuda, I. Hachiya, Chem. Lett. 1996, 25, 407.
[9] M. A. Kraus, Synthesis 1973, 361.
[10] Y. Han, L. Cai, Tetrahedron Lett. 1997, 38, 5423.
[11] I. Ugi, Angew. Chem., Int. Ed. 1982, 21, 810; J. Waki, J. Meienhofer, J. Org. Chem. 1977, 42, 2019.
[12] F. Effenberger, J. Eichhorn, Tetrahedron: Asymmetry 1997, 8, 469.

Helvetica Chimica Acta – Vol. 95 (2012)
1107
[13] U. Schçllkopf, Angew. Chem., Int. Ed. 1977, 16, 339.
[14] P. Wu, Z. Wang, M. Cheng, L. Zhou, J. Sun, Tetrahedron 2008, 64, 11304.
[15] F. F. Blicke, C.-J. Lu, J. Am. Chem. Soc. 1952, 74, 3933; F. M. F. Chen, N. L. Benoiton, Synthesis 1979,
709.
[16] H. Yale, J. Org. Chem. 1971, 36, 3238; L. Kisfaludy, L. ꢂtvçs Jr., Synthesis 1987, 510; W. Duczek, J.
Deutsch, S. Vieth, H.-J. Niclas, Synthesis 1996, 37.
[17] M. Mihara, Y. Ishino, S. Minakara, M. Komatsu, Synthesis 2003, 2317.
[18] B. Das, M. Krishnaiah, P. Balasubramanyam, B. Veeranjaneyulu, D. N. Kumar, Tetrahedron Lett.
2008, 49, 2225; P. G. Reddy, G. D. K. Kumar, S. Bhaskaran, Tetrahedron Lett. 2000, 41, 9149.
[19] J. B. Sweeney, Chem. Soc. Rev. 2002, 31, 247.
[20] V. H. Dahanukar, L. A. Zavialov, Curr. Opin. Drug Discovery Dev. 2002, 5, 918.
[21] A. Padwa, S. S. Murphree, Arkivoc 2006, iii, 6.
[22] ꢃAziridines and Epoxides in Organic Synthesisꢄ, Ed. A. K. Yudin, Wiley-VCH, Weinheim, 2006.
[23] D. M. Hodgson, P. G. Humphreys, S. P. Hughes, Pure Appl. Chem. 2007, 79, 269.
[24] L. Marzorati, G. C. Barazzone, M. A. Bueno Filho, B. Wladislaw, C. D. Vitta, Tetrahedron Lett. 2007,
48, 6509.
[25] G. S. Singh, M. Dꢄhooghe, N. De Kimpe, Chem. Rev. 2007, 107, 2080.
[26] H. Naeimi, K. Rabiei, Chin. Chem. Lett. 2011, 22, 1273.
[27] A. F. Khlebnikov, M. S. Novikov, M. V. Golovkina, P. P. Petrovskii, A. S. Konev, D. S. Yufit, H.
Stoeckli-Evans, Org. Biomol. Chem. 2011, 9, 3886.
[28] M. Mihara, Y. Ishino, S. Minakata, M. Komatsu, J. Org. Chem. 2005, 70, 5320.
[29] R. R. Kostikov, A. F. Khlebnikov, K. A. Oglobin, Zh. Org. Khim. 1977, 13, 1857.
[30] A. F. Khlebnikov, K. A. Oglobin, Zh. Org. Khim. 1973, 9, 2346.
[31] G. A. Yost, L. L. Miller, J. Agric. Food Chem. 1976, 24, 724.
[32] a) E. K. Fields, S. M. Sandri, Chem. Ind. (London) 1959, 1216; b) A. G. Cook, E. K. Fields, J. Org.
Chem. 1962, 27, 3686.
[33] M. K. Meilahn, D. K. Olsen, W. J. Brittain, R. T. Anders, J. Org. Chem. 1978, 43, 1346; J. Graefe, Z.
Chem. 1974, 14, 469.
[34] M. Amanullah, S. K. Sadozai, W. Rehman, Z. H. A. Rauf, M. Iqbal, African J. Biotechnol. 2011, 10,
209.
[35] S. J. Chung, D. H. Kim, Tetrahedron 1995, 51, 12549; M. S. Goodman, A. D. Hamilton, J. Weiss, J.
Am. Chem. Soc. 1995, 117, 8447.
[36] A. F. Khlebnikov, T. Y. Nikiforova, M. S. Novikov, R. R. Kostikov, Synthesis 1997, 677.
[37] M. K. Meilahn, L. L. Augenstein, J. L. McManaman, J. Org. Chem. 1971, 36, 3627.
[38] Y. Ohshiro, H. Ohnishi, M. Komatsu, J. Jpn. Oil Chem. Soc.1987, 36, 884.
[39] H. Naeimi, F. Salimi, K. Rabiei, J. Mol. Catal. A: Chem. 2006, 260, 100; H. Naeimi, H. Sharghi, F.
Salimi, K. Rabiei, Heteroatom Chem. 2008, 19, 43.
[40] H. Schiff, Ann. Chem. Pharm. Suppl. 1864, 3, 343.
[41] K. Rabiei, Ph.D. Thesis, University of Kashan, Iran, 2010.
Received November 17, 2012