Green procedure for the synthesis of β-nitro sulfides by Michael addition of thiols to nitroolefins

Article abstract of DOI:10.1080/00397910802431065

Michael addition of thiols to nitroolefins was carried out in water at room temperature without any catalyst, and β-nitro sulfides were obtained in excellent yields. This is the first example of Michael addition of thiols to nitroolefins in water without

Full text of DOI:10.1080/00397910802431065

This article was downloaded by: [Umeå University Library]
On: 29 September 2013, At: 13:28
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
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic
Organic Chemistry
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/lsyc20
Green Procedure for the
Synthesis of β-Nitro Sulfides by
Michael Addition of Thiols to
Nitroolefins
Xin-Ping Hui a , Chao Yin a , Jun Ma a & Peng-Fei Xu a
a State Key Laboratory of Applied Organic Chemistry,
College of Chemistry and Chemical Engineering
Lanzhou University, Lanzhou, China
Published online: 27 Jan 2009.
To cite this article: Xin-Ping Hui , Chao Yin , Jun Ma & Peng-Fei Xu (2009)
Green Procedure for the Synthesis of β-Nitro Sulfides by Michael Addition of
Thiols to Nitroolefins, Synthetic Communications: An International Journal
for Rapid Communication of Synthetic Organic Chemistry, 39:4, 676-690, DOI:
10.1080/00397910802431065
To link to this article: http://dx.doi.org/10.1080/00397910802431065
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

Synthetic Communications1, 39: 676–690, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802431065
Green Procedure for the Synthesis of
b-Nitro Sulfides by Michael Addition of
Thiols to Nitroolefins
Xin-Ping Hui, Chao Yin, Jun Ma, and Peng-Fei Xu
State Key Laboratory of Applied Organic Chemistry, College of Chemistry
and Chemical Engineering, Lanzhou University, Lanzhou, China
Abstract: Michael addition of thiols to nitroolefins was carried out in water at
room temperature without any catalyst, and b-nitro sulfides were obtained in
excellent yields. This is the first example of Michael addition of thiols to nitro-
olefins in water without use of any catalyst. It provides a highly efficient, general,
and practical green route to synthesis of b-nitro sulfides. Twenty-four new b-nitro
sulfides were synthesized using this technique.
Keywords: Nitroolefin, b-nitro sulfide, thia-Michael addition, thiol
Environmentally benign reactions have become the targets of synthetic
organic chemists today. Organic reactions in water have received increas-
ing attention particularly because of their environmental acceptability and
low cost.[1] The development of efficient transformations in water without
any catalyst is highly appreciated.
Conjugated addition is one of the most powerful bond-forming
reactions to construct highly functionalized building blocks for the total
synthesis of natural and biologically active compounds. In synthetic
organic chemistry, the scope and applications of organo-sulfur com-
pounds have increased tremendously because sulfur-containing groups
Received March 19, 2008.
Address correspondence to Xin-Ping Hui, State Key Laboratory of Applied
Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou
University, Lanzhou 730000, China. E-mail: huixp@lzu.edu.cn
676

Green Procedure for the Synthesis of b-Nitro Sulfides
677
serve as important auxiliaries in many synthetic sequences.[2] Their
importance both in biochemical process[3] and in synthesis[4] is well recog-
nized. Among Michael acceptors, nitroolefin is very attractive because of
the strong electron deficiency of nitro group within it and is often
described as a ‘‘synthetic chameleon’’[5] because the nitro group is readily
converted into other functional groups such as keto, cyano, and amino
groups.[6,7]
Although thiols are good reagents for Michael addition to nitroole-
fins, the reactions are conventionally promoted in the presence of
butyllithium, base,[8] or tetramethylammonium fluoride[9] in organic
solvent. Ranu et al.[10] reported an efficient conjugate addition of thiols
to electron-deficient alkenes catalyzed by molten tetrabutylammonium
bromide under solvent-free conditions. To our knowledge, there is no
report of thia-Michael addition of nitroolefins in water without any
catalyst. Herein, we report a very simple and green procedure for
the conjugated addition of thiols to nitroolefins in water at room
temperature without any catalyst, leading to an efficient synthesis of
b-nitro sulfides (Scheme 1).
Michael addition of benzenthiol to 2-nitroethenylbenzene in various
solvents was first examined, and the results are summarized in Table 1.
When toluene, THF, and CH2Cl2 were used as solvents, no product
was obtained after 36 h at room temperature (Table 1, entries 1–3). It
was observed that the reaction in methanol or diethyl ether under identi-
cal conditions was very slow (Table 1, entries 4 and 5). To our delight,
thia-Michael addition proceeded extremely fast in water without any
catalyst or additive, giving the desired product in 95% isolated yield
(Table 1, entry 6). The amount of water used in the reaction did not have
any significant influence on the overall rate and the yield of the reaction.
When 2-nitroethenylbenzene (0.5 mmol) was treated with benzenethiol
(0.55 mmol) in 2 mL and 10 mL of water for 5 min, the product was
afforded in 91 and 93% yields, respectively.
Generality of this thia-Michael addition was then examined on a
variety of thiols including aromatic thiols and alkyl thiols with nitroole-
fins under the optimized reaction conditions. The results are listed in
Scheme 1. Michael addition of thiols to nitroolefins in water.

678
X.-P. Hui et al.
Table 1. Comparison of Michael addition of benzenethiol to 2-nitroethenylben-
zene in organic solvents and water
Entry
Solvent (5.0 mL)
Time
Yield (%)
1
2
3
4
5
6
toluene
THF
CH2Cl2
CH3OH
Et2O
36 h
36 h
36 h
48 h
36 h
5 min
NR
NR
NR
92
95
95
H2O
Table 2, and b-nitro sulfides could be obtained in good yields of 84–96%.
The reaction rate of aromatic thiols was found to be faster than that of
alkyl thiols (Table 2, products 1–5). For 4-substituted phenyl nitroolefins,
the moderate electron-withdrawing and electron-donating substituents
were unfavorable to thia-Michael addition (Table 2, products 2 and 3).
However, alkyl nitroolefins were favorable to this reaction (Table 2,
products 4 and 5).
The reaction proceeds faster in water than that in organic solvents
without catalyst, which might be due to the promotion of water by the
hydrogen bond between water and oxygen atom of the nitroolefin,
increasing electrophilic property of the b-carbon. The proposed
mechanism is depicted in Scheme 2. On the other hand, the hydrogen
bond between water and hydrogen atom of the thiol increases the
nucleophilic property of the thiol. Thus, simultaneous activation of
the nitroolefin and the thiol takes place through hydrogen bond forma-
tion with water via I. Then Michael addition via II followed by one pro-
ton transfer leads to the conjugated adduct. In fact, the reaction rate of
various thiols with nitroolefins was affected by the ability of the hydro-
gen bond formation between the thiol and water. This explains why the
reaction rate of aromatic thiol was found to be faster than that of alkyl
thiol (Table 2).
In summary, we have described herein an efficient and fast method
for synthesis of b-nitro sulfides by virtue of water-mediated conjugated
addition of thiols to nitroolefins in excellent yields. This methodology

Green Procedure for the Synthesis of b-Nitro Sulfides
679
Table 2. Michael addition of thiols to nitroolefins in water
Michael
acceptors
Yield
(%)a
Entry Products
Thiols
Time
5 min
1
2
3
4
5
6
1a
1b
1c
1d
1e
2a
95
10 min 94
10 min 96
1 h
2 h
91
93
30 min 93
7
8
2b
2c
30 min 90
30 min 95
9
2d
4 h
91
(Continued )

680
X.-P. Hui et al.
Table 2. Continued
Entry Products
Michael
acceptors
Yield
(%)a
Thiols
Time
8 h
10
2e
90
11
3a
2 h
2 h
2 h
6 h
96
92
94
90
12
13
14
3b
3c
3d
15
16
3e
4a
8 h
91
15 min 85
17
18
4b
4c
15 min 87
15 min 89
(Continued )

Green Procedure for the Synthesis of b-Nitro Sulfides
681
Table 2. Continued
Michael
acceptors
Yield
(%)a
Entry Products
Thiols
Time
2 h
19
4d
88
20
4e
4 h
89
21
22
23
24
5a
5b
5c
5d
15 min 92
15 min 91
15 min 90
2 h
4 h
84
85
25
5e
is of interest because of the use of water as the solvent without any
catalyst; thus it minimizes the cost and environmental pollution produced
by the solvent.

682
X.-P. Hui et al.
Scheme 2. Proposed mechanism of Michael addition of thiols to nitroolefins in
water.
EXPERIMENTAL
Melting points were determined on an X-4 melting-point apparatus
1
and were uncorrected. H NMR and 13C NMR spectra were obtained
using the Varian Mercury Plus 300BB or Bruker AM-400 in CDCl3.
IR spectra were recorded using a Nicolet Nexus 670 Fourier transform
infrared (FT-IR) spectrometer in KBr disk. Elemental analyses were
determined by Elemental Vario EL instrument. Mass spectra were per-
formed on Thermo DSQ mass instrument (EI at 70 eV).
Nitroolefins were synthesized according to literature methods.[11]
General Procedure for Thia-Michael Addition of Thiols to Nitroolefins
Thiol (0.55 mmol) was added to a mixture of nitroolefin (0.5 mmol) in
water (5 mL), and the mixture was vigorously stirred at room tempera-
ture until the nitroolefin was consumed completely (5 min). The reaction
mixture was extracted with EtOAc (5 mL ꢀ 3), and the combined organic
phase was washed with saturated Na2CO3 solution (15 mL ꢀ 3) and brine
(15 mL ꢀ 3), dried over anhydrous MgSO4, and concentrated under
reduced pressure to give the crude product. The crude product was
purified by flash-column chromatography to afford desired b-nitro
sulfides.

Green Procedure for the Synthesis of b-Nitro Sulfides
683
Data
(2-Nitro-1-phenylethyl)(phenyl) Sulfide (1a)
1H NMR (300 MHz, CDCl3): d ¼ 4.69–4.92 (m, 3H, CH2, CH), 7.25–7.42
(m, 10H, ArH), which is in accord with Ref. 12.
(2-Nitro-1-phenylethyl)(p-tolyl) Sulfide (1b)
1
White solid, mp 84–85 ꢁC. H NMR (300 MHz, CDCl3): d ¼ 2.35 (s, 3H,
CH3) 4.69–4.84 (m, 3H, CH2, CH), 7.13 (d, J ¼ 7.8 Hz, 2H, ArH), 7.23–
7.33 (m, 7H, ArH). 13C NMR (75 MHz, CDCl3): d ¼ 139.20, 136.38,
134.25, 130.08, 128.88, 128.50, 128.06, 127.59, 78.46, 50.08, 21.16. IR
(KBr): 1555, 1537, 13756, 805, 746, 698, 496 cmꢂ1. MS (EI, 70 eV): m=z
(%) ¼ 273.0 (72) [Mþ]. Anal. calcd. for C15H15NO2S: C, 65.91; H, 5.53;
N, 5.12. Found: C, 65.71; H, 5.61; N, 4.96.
(4-Chlorophenyl) (2-Nitro-1-phenylethyl) Sulfide (1c)
1
Yellowish oil; H NMR (300 MHz, CDCl3): d ¼ 4.69–4.84 (m, 3H, CH2,
CH), 7.20–7.33 (m, 9H, ArH). 13C NMR (75 MHz, CDCl3): d ¼ 135.91,
135.15, 135.07, 129.96, 129.36, 128.91, 128.62, 127.50, 78.13, 49.90. Anal.
calcd. for C14H12ClNO2S: C, 57.24; H, 4.12; N, 4.77. Found: C, 57.20; H,
4.14; N, 4.86.
Benzyl (2-Nitro-1-phenylethyl) Sulfide (1d)
Yellowish oil. 1H NMR (300 MHz, CDCl3): d ¼ 3.57 (d, J ¼ 13.5 Hz, 1H,
PhCH2), 3.67 (d, J ¼ 13.5 Hz, 1H, PhCH2), 4.40 (dd, J ¼ 9.3, 6.9 Hz, 1H,
CH), 4.59–4.72 (m, 2H, CH2NO2), 7.22–7.37 (m, 10H, ArH). 13C NMR
(75 MHz, CDCl3): d ¼ 136.86, 136.75, 128.85, 128.77, 128.53, 128.31,
127.61, 127.34, 78.79, 45.69, 35.75. MS (EI, 70 eV): m=z (%) ¼ 273.0
(38) [Mþ]. Anal. calcd. for C15H15NO2S: C, 65.91; H, 5.53; N, 5.12.
Found: C, 65.82; H, 5.64; N, 4.98.
(2-Nitro-1-phenylethyl) (Pentyl) Sulfide (1e)
1
Yellowish oil. H NMR (300 MHz, CDCl3): d ¼ 0.87 (t, J ¼ 7.2 Hz, 3H,
CH3), 1.23–1.32 (m, 4H, CH2), 1.51–1.56 (m, 2H, CH2), 2.44 (t,
J ¼ 7.5 Hz, 2H, CH2), 4.55 (dd, J ¼ 7.5, 4.2 Hz, 1H, CH), 4.75 (d,

684
X.-P. Hui et al.
J ¼ 7.5 Hz, 2H, CH2NO2), 7.30–7.36 (m, 5H, ArH). 13C NMR (75 MHz,
CDCl3): d ¼ 137.38, 128.90, 128.31, 127.53, 79.22, 46.43, 31.52, 30.76,
28.71, 22.07, 13.83. MS (EI, 70 eV): m=z (%) ¼ 253.1 (35) [Mþ]. Anal.
calcd. for C13H19NO2S: C, 61.63; H, 7.56; N, 5.53. Found: C, 61.47; H,
7.60; N, 5.43.
(1-(4-Chlorophenyl)-2-nitroethyl) (Phenyl) Sulfide (2a)
White solid, mp 76–77 ꢁC. 1H NMR (400MHz, CDCl3): d ¼ 4.69–4.87 (m,
3H, CH2, CH), 7.17–7.21 (m, 2H, ArH), 7.29–7.39 (m, 7H, ArH). 13C NMR
(100MHz, CDCl3): d ¼ 134.77, 134.27, 133.82, 131.15, 129.31, 129.02,
128.89, 78.07, 49.01. IR (KBr): 1549, 1374, 1090, 799, 749, 687 cmꢂ1. MS
(EI, 70eV): m=z (%) ¼ 292.9 (18) [Mþ]. Anal. calcd. for C14H12ClNO2S:
C, 57.24; H, 4.12; N, 4.77. Found: C, 57.26; H, 4.02; N, 4.71.
(1-(4-Chlorophenyl)-2-nitroethyl) (p-Tolyl) Sulfide (2b)
1
White solid, mp 64–65 ꢁC. H NMR (400 MHz, CDCl3): d ¼ 2.28 (s, 3H,
CH3), 4.58–4.73 (m, 3H, CH2, CH), 7.05–7.12 (m, 4H, ArH), 7.18–7.25,
(m, 4H, ArH). 13C NMR (100 MHz, CDCl3): d ¼ 139.44, 134.94, 134.39,
134.24, 130.13, 129.02, 128.92, 127.42, 78.11, 49.32, 21.12. Anal. calcd. for
C15H14ClNO2S: C, 58.53; H, 4.58; N, 4.55. Found: C, 58.69; H, 5.74; N, 4.32.
(4-Chlorophenyl) (1-(4-Chlorophenyl)-2-nitroethyl) Sulfide (2c)
Yellowish oil. 1HNMR (400 MHz, CDCl3): d ¼ 4.68–4.83 (m, 3H, CH2, CH),
7.15–7.17 (m, 2H, ArH), 7.28–7.31 (m, 6H, ArH). 13C NMR (100 MHz,
CDCl3): d ¼ 135.36, 135.30, 134.56, 134.45, 129.50, 129.13, 128.88, 77.92,
49.29. MS (EI, 70 eV): m=z (%) ¼ 328.1 (22) [Mþ]. Anal. calcd. for
C14H11Cl2NO2S: C, 51.23; H, 3.38; N, 4.27. Found: C, 51.12; H, 3.56; N, 4.53.
Benzyl (1-(4-Chlorophenyl)-2-nitroethyl) Sulfide (2d)
Yellowish oil. 1H NMR (400 MHz, CDCl3): d ¼ 3.58 (d, J ¼ 13.6 Hz, 1H,
PhCH2), 3.69 (d, J ¼ 13.6 Hz, 1H, PhCH2), 4.37 (dd, J ¼ 7.2, 8.8 Hz, 1H,
CH), 4.64 (dd, J ¼ 1.6, 8.4 Hz, 2H, CH2), 7.19–7.36 (m, 9H, ArH). 13C
NMR (100 MHz, CDCl3): d ¼ 136.51, 135.53, 134.08,129.05, 128.76,
128.62, 127.48, 78.60, 45.01, 35.84. MS (EI, 70 eV): m=z (%) ¼ 307.0
(20) [Mþ]. Anal. calcd. for C15H14ClNO2S: C, 58.53; H, 4.58; N, 4.55.
Found: C, 58.67; H, 4.43; N, 4.72.

Green Procedure for the Synthesis of b-Nitro Sulfides
685
(1-(4-Chlorophenyl)-2-nitroethyl) (Pentyl) Sulfide (2e)
1
Yellowish oil. H NMR (400 MHz, CDCl3): d ¼ 0.86 (t, J ¼ 7.2 Hz, 3H,
CH3), 1.23–1.30 (m, 4H, CH2), 1.49–1.56 (m, 2H, CH2), 2.42 (t,
J ¼ 7.2 Hz, 2H, CH2), 4.51 (dd, J ¼ 8.8, 7.6 Hz, 1H, CH), 4.68–4.76 (m,
2H, CH2NO2), 7.27–7.33 (m, 4H, ArH). 13C NMR (100 MHz, CDCl3):
d ¼ 136.02, 133.95, 128.99, 128.88, 78.86, 45.64, 31.45, 30.65, 28.58,
21.99, 13.73. Anal. calcd. for C13H18ClNO2S: C, 54.25; H, 6.30; N,
4.87. Found: C, 54.42; H, 6.47; N, 4.94.
(2-Nitro-1-p-tolyl-ethyl) (Phenyl) Sulfide (3a)
1
White solid, mp 80–81ꢁC. H NMR (300 MHz, CDCl3): d ¼ 2.33 (s, 3H,
CH3), 4.65–4.89 (m, 3H, CH2,CH), 7.12–7.42 (m, 9H, ArH). 13C NMR
(75 MHz, CDCl3): d ¼ 138.42, 133.46, 133.10, 132.08, 129.59, 129.26
128.58, 127.42, 78.55, 49.51, 21.07. IR (KBr): 1551, 1537, 1375, 845, 787,
750, 488 cmꢂ1. MS (EI, 70 eV): m=z (%) ¼ 273 (27) [Mþ]. Anal. calcd. for
C15H15NO2S: C, 65.91; H, 5.53; N, 5.12. Found: C, 65.90; H, 5.61; N, 4.96.
(2-Nitro-1-p-tolylethyl) (p-Tolyl) Sulfide (3b)
1
White solid, mp 86–87 ꢁC. H NMR (300 MHz, CDCl3): d ¼ 2.33 (s, 3H,
CH3), 2.34 (s, 3H, CH3), 4.64–4.84 (m, 3H, CH2, CH), 7.11–7.17 (m, 6H,
ArH), 7.29 (d, J ¼ 7.5 Hz, 2H, ArH). 13C NMR (75 MHz, CDCl3):
d ¼ 139.03, 138.33, 134.05, 133.25, 130.05, 129.56, 128.32, 127.42,
78.57, 49.82, 21.12, 21.08. Anal. calcd. for C16H17NO2S: C, 66.87; H,
5.96; N, 4.87. Found: C, 66.65; H, 5.74; N, 4.98.
(4-Chlorophenyl) (2-Nitro-1-p-tolylethyl) Sulfide (3c)
1
White solid, mp 62–63 ꢁC. H NMR (300 MHz, CDCl3): d ¼ 2.33 (s, 3H,
CH3), 4.66–4.85 (m, 3H, CH2, CH), 7.27 (s, 4H, ArH); 7.27–7.32 (m, 4H,
ArH). 13C NMR (75 MHz, CDCl3): d ¼ 138.47, 134.90, 134.85, 132.77,
130.24, 129.56, 129.30, 127.32, 78.23, 49.61, 21.01. MS (EI, 70 eV): m=z
(%) ¼ 307.0 (24) [Mþ]. Anal. calcd. for C15H14ClNO2S: C, 58.53; H,
4.58; N, 4.55. Found: C, 58.35; H, 5.69; N, 4.69.
Benzyl (2-Nitro-1-p-tolylethyl) Sulfide (3d)
1
Yellowish oil. H NMR (300 MHz, CDCl3): d ¼ 2.34 (s, 3H, CH3), 3.68
(d,J ¼ 13.5 Hz, 1H, PhCH2), 3.59 (d, J ¼ 13.5 Hz, 1H, PhCH2), 4.39

686
X.-P. Hui et al.
(dd, J ¼ 8.7, 6.3 Hz, 1H, CH), 4.59–4.72 (m, 2H, CH2), 7.16 (s, 4H, ArH),
7.25–7.37 (m, 5H, ArH). 13C NMR (75 MHz, CDCl3): d ¼ 138.28, 136.93,
133.82, 129.64, 128.86, 128.62, 127.58, 127.41, 79.05, 45.56, 38.85, 21.09.
MS (EI, 70 eV): m=z (%) ¼ 287.0 (41) [Mþ]. Anal. calcd. for C16H17NO2S:
C, 66.87; H, 5.96; N, 4.87. Found: C, 66.99; H, 5.73; N, 4.64.
(2-Nitro-1-p-tolylethyl) (Pentyl) Sulfide (3e)
1
Yellowish oil. H NMR (300 MHz, CDCl3): d ¼ 0.87 (t, J ¼ 6.9 Hz, 3H,
CH3), 1.27–1.32 (m, 4H, CH2), 1.51–1.56 (m, 2H, CH2), 2.33 (s, 3H,
CH3), 2.43 (t, J ¼ 7.2 Hz, 2H, CH2), 4.52 (t, J ¼ 8.1 Hz, 1H, CH), 4.73
(d, J ¼ 8.1 Hz, 2H, CH2), 7.15 (d, J ¼ 8.1 Hz, 2H, ArH), 7.22 (d,
J ¼ 8.1 Hz, 2H, ArH). 13C NMR (75 MHz, CDCl3): d ¼ 138.17, 134.29,
129.61, 127.42, 79.37, 46.23, 31.54, 30.82, 28.77, 22.12, 21.07, 13.85. Anal.
calcd. for C14H21NO2S: C, 62.89; H, 7.92; N, 5.24. Found: C, 62.70; H,
7.71; N, 5.12.
(1-Cyclohexyl-2-nitroethyl) (Phenyl) Sulfide (4a)
1
Yellow oil. H NMR (300 MHz, CDCl3): d ¼ 1.13–1.34 (m, 4H, ChH),
1.39–1.51 (m, 1H, ChH), 1.62–1.92 (m, 6H, ChH), 3.65–3.71 (m, 1H,
CH), 4.42 (dd, J ¼ 12.9, 6.6 Hz, 1H, CH2), 4.64 (dd, J ¼ 12.9, 7.2 Hz, 1H,
CH2), 7.27–7.36 (m, 3H, ArH), 7.42–7.47 (m, 2H, ArH). 13C NMR
(75 MHz, CDCl3): d ¼ 133.48, 132.27, 129.19, 127.74, 76.90, 52.85, 39.63,
30.44, 28.54, 26.01, 25.96, 25.91. IR: 2928, 2854, 1554, 1445, 1376,
746, 694 cmꢂ1. MS (EI, 70 eV): m=z (%) ¼ 265.0 (26) [Mþ]. Anal. calcd.
for C14H19NO2S: C, 63.36; H, 7.22; N, 5.28. Found: C, 63.58; H, 6.87;
N, 5.23.
(1-Cyclohexyl-2-nitroethyl) (p-Tolyl) Sulfide (4b)
Yellowish oil. 1H NMR (300 MHz, CDCl3): d ¼ 1.09–1.33 (m, 4H, ChH),
1.39–1.59 (m, 1H, ChH), 1.62–1.92 (m, 6H, ChH), 2.31 (s, 3H, CH3),
3.56–3.62 (m, 1H, CH), 4.40 (dd, J ¼ 12.9, 6.6 Hz, CH2), 4.63 (dd,
J ¼ 12.9, 8.7 Hz, CH), 4.59–4.63 (m, 1H, CH), 7.14 (d, J ¼ 7.8 Hz 2H,
ArH), 7.34 (d, J ¼ 7.8 Hz, 2H, ArH). 13C NMR (75 MHz, CDCl3):
d ¼ 138.12, 133.03, 129.08, 129.67, 76.95, 53.36, 36.61, 30.47, 28.62,
26.06, 26.00, 25.90, 20.99. Anal. calcd. for C15H21NO2S: C, 64.48; H,
7.58; N, 5.01. Found: C, 64.30; H, 7.65; N, 4.91.

Green Procedure for the Synthesis of b-Nitro Sulfides
687
(4-Chlorophenyl) (1-cyclohexyl-2-nitroethyl) Sulfide (4c)
Yellowish oil. 1H NMR (300 MHz, CDCl3): d ¼ 1.10–1.29 (m, 4H, ChH),
1.38–1.43 (m, 1H, ChH), 1.61–1.89 (m, 6H, ChH), 3.58–3.65 (m, 1H,
CH), 4.40 (dd, J ¼ 12.9, 6.9 Hz, 1H, CH2NO2), 4.63 (dd, J ¼ 12.9,
7.8 Hz, 1H, CH2NO2), 7.28–7.39 (m, 4H, ArH). 13C NMR (75 MHz,
CDCl3): d ¼ 133.94, 133.71, 132.11, 129.33, 76.94, 53.38, 39.86, 30.41,
28.73, 25.98, 25.93, 25.88. Anal. calcd. for C14H18ClNO2S: C, 56.08; H,
6.05; N, 4.67. Found: C, 56.29; H, 6.27; N, 4.86.
Benzyl (1-Cyclohexyl-2-nitroethyl) Sulfide (4d)
1
Colorless oil. H NMR (300 MHz, CDCl3): d ¼ 0.97–1.29 (m, 6H, ChH),
1.40–1.49 (m, 1H, ChH), 1.62–1.71 (m, 4H, ChH), 3.11–3.18 (m, 1H,
CH), 3.71 (d, J ¼ 12.9 Hz, 1H, PhCH2), 3.76 (d, J ¼ 12.9 Hz, 1H, PhCH2),
4.35 (dd, J ¼ 12.9, 7.5 Hz, 1H, CH2NO2), 4.55 (dd, J ¼ 12.9, 7.5 Hz, 1H,
CH2NO2), 7.27–7.33 (m, 5H, ArH). 13C NMR (75 MHz, CDCl3):
d ¼ 137.49, 128.98, 128.58, 127.36, 77.93, 48.62, 40.07, 37.13, 30.15,
28.30, 26.00, 25.95. MS (EI, 70 eV): m=z (%) ¼ 279.1 (48) [Mþ]. Anal.
calcd. for C15H21NO2S: C, 64.48; H, 7.58; N, 5.01. Found: C, 64.31; H,
7.68; N, 4.95.
(1-Cyclohexyl-2-nitroethyl) (Pentyl) Sulfide (4e)
1
Colorless oil. H NMR (300 MHz, CDCl3): d ¼ 0.89 (t, J ¼ 6.9 Hz, 3H,
CH3), 1.06–1.43 (m, 9H, ChH, CH2), 1.52–1.77 (m, 8H, ChH, CH2),
2.52 (t, J ¼ 7.5 Hz, 2H, CH2), 3.15–3.21 (m, 1H, CH), 4.44 (dd,
J ¼ 12.3, 7.8 Hz, 1H, CH2NO2), 4.60 (dd, J ¼ 12.3, 7.5 Hz, 1H, CH2NO2).
13C NMR (75 MHz, CDCl3): d ¼ 78.26, 49.86, 40.35, 32.96, 30.87, 30.43,
29.31, 28.45, 26.12, 26.05, 26.02, 22.20, 13.91. MS (EI, 70 eV): m=z
(%) ¼ 259.1 (18) [Mþ]. Anal. calcd. for C13H25NO2S: C, 60.19; H, 9.71;
N, 5.40. Found: C, 60.32; H, 9.60; N, 5.62.
(3-Methyl-1-nitrobutan-2-yl) (Phenyl) Sulfide (5a)
Yellowish oil. 1H NMR (300 MHz, CDCl3): d ¼ 1.06 (d, J ¼ 5.4 Hz,
3H, CH3), 1.52 (d, J ¼ 5.4 Hz, 3H, CH3), 2.08–2.08 (m, 1H, CH),
3.67–3.73 (m, 1H, CH), 4.44 (dd, J ¼ 12.9, 8.1 Hz, 1H, CH2), 4.61 (dd,
J ¼ 11.7, 8.1 Hz, 1H, CH2), 7.25–7.36 (m, 3H, ArH), 7.43–7.48 (m, 2H,
ArH). 13C NMR (75 MHz, CDCl3): d ¼ 133.33, 132.43, 129.26, 127.84,
77.30, 53.68, 29.87, 20.16, 17.87. IR: 2966, 2875, 1554, 1475, 1433,

688
X.-P. Hui et al.
1376, 746, 693 cmꢂ1. MS (EI, 70 eV): m=z (%) ¼ 224.9 (35) [Mþ]. Anal.
calcd. for C14H19NO2S: C, 58.64; H, 6.71; N, 6.22. Found: C, 58.45; H,
6.51; N, 6.21.
(3-Methyl-1-nitrobutan-2-yl) (p-Tolyl) Sulfide (5b)
1
Yellowish oil. H NMR (300 MHz, CDCl3): d ¼ 1.00 (d, J ¼ 6.3 Hz, 3H,
CH3), 1.14 (d, J ¼ 6.3 Hz, 3H, CH3), 1.99–2.05 (m, 1H, CH), 2.34 (s,
3H, CH3), 3.59–3.65 (m, 1H, CH), 4.42 (dd, J ¼ 12.9, 7.2 Hz,, 1H,
CH2), 4.59 (dd, J ¼ 12.9, 8.7 Hz, 1H, CH2), 7.14 (d, J ¼ 7.8 Hz, 2H,
ArH), 7.36 (d, J ¼ 7.8 Hz, 2H, ArH). 13C NMR (75 MHz, CDCl3):
d ¼ 138.29, 138.16, 130.08, 129.44, 77.35, 54.21, 29.76, 21.09, 20.24,
17.91. Anal. calcd. for C12H17NO2S: C, 60.22; H, 7.16; N, 5.85. Found:
C, 60.04; H, 7.28; N, 5.99.
(4-Chlorophenyl) (3-Methyl-1-nitrobutan-2-yl) Sulfide (5c)
1
Colorless oil. H NMR (300 MHz, CDCl3): d ¼ 1.05 (d, J ¼ 7.2 Hz, 3H,
CH3), 1.13 (d, J ¼ 7.2 Hz, 3H, CH3), 2.00–2.07 (m, 1H, CH), 3.61–3.68
(m, 1H, CH), 4.42 (dd, J ¼ 12.9, 7.2 Hz, 1H, CH2), 4.60 (dd, J ¼ 12.9,
8.1 Hz, CH2), 7.28–7.32 (m, 2H, ArH), 7.37–7.40 (m, 2H, ArH). 13C
NMR (75 MHz, CDCl3): d ¼ 134.09, 133.83, 131.90, 129.39, 77.26,
54.13, 30.06, 20.09, 17.99. MS (EI, 70 eV): m=z (%) ¼ 259.0 (26) [Mþ].
Anal. calcd. for C11H14ClNO2S: C, 50.86; H, 5.43; N, 5.39. Found: C,
50.74; H, 5.60; N, 5.30.
Benzyl (3-Methyl-1-nitrobutan-2-yl) Sulfide (5d)
1
Colorless oil. H NMR (300 MHz, CDCl3): d ¼ 0.89 (d, J ¼ 5.1 Hz, 3H,
CH3), 0.91 (d, J ¼ 5.1 Hz, 3H, CH3), 1.84–1.90 (m, 1H, CH), 3.14–3.20
(m, 1H, CH), 3.71 (d, J ¼ 13.2 Hz, 1H, PhCH2), 3.77 (d, J ¼ 13.2 Hz,
1H, PhCH2), 4.36 (dd, J ¼ 12.6, 7.5 Hz, 1H, CH2), 4.52 (dd, J ¼ 12.6,
7.8 Hz, 1H, CH2), 7.25–7.35 (m, 5H, ArH). 13C NMR (75 MHz, CDCl3):
d ¼ 137.47, 128.95, 128.54, 127.33, 78.24, 49.23, 36.91, 29.96, 19.90, 17.53.
Anal. calcd. for C12H17NO2S: C, 60.22; H, 7.16; N, 5.85. Found: C,
60.43; H, 7.01; N, 5.71.
(3-Methyl-1-nitrobutan-2-yl) (Pentyl) Sulfide (5e)
1
Colorless oil. H NMR (300 MHz, CDCl3): d ¼ 0.91 (d, J ¼ 7.2 Hz, 3H,
CH3), 0.95 (d, J ¼ 9.6 Hz, 3H, CH3), 1.05 (d, J ¼ 9.6 Hz, 3H, CH3),

Green Procedure for the Synthesis of b-Nitro Sulfides
689
1.31–1.36 (m, 4H, CH2), 1.52–1.59 (m, 2H, CH2), 1.92–1.98 (m, 1H, CH),
2.53 (t, J ¼ 7.2 Hz, 2H, CH2), 3.17–3.24 (m, 1H, CH), 4.45 (dd, J ¼ 12.3,
8.1 Hz, 1H, CH2), 4.65 (dd, J ¼ 12.6, 8.1 Hz, 1H, CH2). 13C NMR
(75 MHz, CDCl3): d ¼ 78.48, 50.50, 32.80, 30.80, 30.24, 29.29, 22.15,
20.11, 17.66, 13.87. MS (EI, 70 eV): m=z (%) ¼ 219.0 (27) [Mþ]. Anal.
calcd. for C10H21NO2S: C, 54.76; H, 9.65; N, 6.39. Found: C, 54.57; H,
9.43; N, 6.20.
ACKNOWLEDGMENTS
This work was supported by National Natural Science Foundation of
China (NSFC 20702022, 20621091).
REFERENCES
1. (a) Grieco, P. A. Organic Synthesis in Water; Blackie Academic and
Professional: London, 1998; (b) Li, C. J.; Chan, T. H. Organic Reactions in
Aqueous Media; Wiley: New York, 1997.
2. Metzner, P.; Thuillier, A. Sulfur Reagents in Organic Synthesis; Academic
Press: New York, 1994.
3. (a) Fluharty, A. L. In The Chemistry of the Thiol Group, Part 2; S. Patai,
(Ed.); Wiley: New York, 1974; (b) Jocelyn, P. C. Biochemistry of the SH
Group; Academic Press: London, 1972; (c) Ivanetich, K. M.; Santi, D. V.
5,6-Dihydropyrimidine adducts in the reactions and interactions of pyrimi-
dines with proteins.Prog. Nucleic Acid Res. Mol. Biol. 1992, 42, 127–156;
(d) Talalay, P.; DeLong, M. J.; Prochaska, H. J. Identification of a common
chemical signal regulating the induction of enzymes that protect against
chemical carcinogenesis.Proc. Natl. Acad. Sci. USA 1988, 85, 8261–8265.
4. (a) Wynberg, H. In Topics in Stereochemistry, E. L. Eliel, S. H. Wilen,
N. L. Allinger (Eds.); Wiley: New York, 1986; vol. 16; (b) Emori, E.; Arai,
T.; Sasai, H.; Shibasaki, M. A catalytic Michael addition of thiols to
a, b-unsaturated carbonyl compounds: Asymmetric Michael additions and
asymmetric protonations. J. Am. Chem. Soc. 1998, 120, 4043–4044, and refer-
ences cited therein.
5. Calderari, G.; Seebach, D. Asymmetric michael additions: Stereoselective
alkylation of chiral, non-racemic enolates by nitroolefins: Preparation of
enantiomerically pure c-aminobutyric and succinic acid derivatives. Helv.
Chim. Acta 1985, 68, 1592–1604.
6. (a) Seebach, D.; Colvin, E. W.; Lehr, F.; Weller, T. Nitroaliphatic
compounds–Ideal intermediates in organic synthesis. Chimia 1979, 33,
1–18; (b) Yoshikoshi, A.; Miyashita, M. Oxoalkylation of carbonyl com-
pounds with conjugated nitro olefins. Acc. Chem. Res. 1985, 18, 284–290.
(c) Rajappa, S. Nitroenamines: Preparation, structure and synthetic

690
X.-P. Hui et al.
potential. Tetrahedron 1981, 37, 1453–1480. (d) Barrett, A. G. M.; Graboski,
G. G. Conjugated nitroalkenes: Versatile intermediates in organic synthesis.
Chem. Rev. 1986, 86, 751–762.
7. (a) Ram, S.; Ehrenkaufer, R. E. A general procedure for mild and rapid
reduction of aliphatic and aromatic nitro compounds using ammonium
formate as a catalytic hydrogen transfer agent. Tetrahedron Lett. 1984, 25,
3415–3418; (b) Tamura, R.; Oda, D.; Kurokawa, H. Synthesis of a-amino
ketone hydrochlorides via chemoselective hydrogenation of a-nitro ketones.
Tetrahedron Lett. 1986, 27, 5759–5762; (c) Kraus, G. A.; Thurston, J.;
Thomas, P. J.; Jacobson, R. A.; Su, Y. 2-Benzoyloxynitroethylene as a
cis-2-aminoethenol equivalent. Tetrahedron Lett. 1988, 29, 1879–1882; (d)
Barrett, A. G. M.; Spilling, C. D. Transfer hydrogenation: A stereospecific
method for the conversion of nitro alkanes into amines. Tetrahedron Lett.
1988, 29, 5733–5734.
8. Kamimura, A.; Sasatani, H.; Hashimoto, T.; Kawai, T.; Hori, K.; Ono, N.
Anti-selective Michael addition of thiols and their analogs to nitro olefins.
J. Org. Chem. 1990, 55, 2437–2442.
´
9. Menand, M.; Dalla, V. TMAF-Catalyzed conjugate addition of oxazolidi-
none and thiols. Synlett 2005, 95–98.
10. Ranu, B. C.; Dey, S. S.; Hajra, A. Catalysis by an ionic liquid: Efficient
conjugate addition of thiols to electron deficient alkenes catalyzed by molten
tetrabutylammonium bromide under solvent-free conditions. Tetrahedron
2003, 59, 2417–2421.
ˆ ´
11. Cote, A.; Lindsay, V. N. G.; Charette, A. B. Application of the chiral
bis(phosphine) monoxide ligand to catalytic enantioselective addition of
dialkylzinc reagents to b-Nitroalkenes. Org. Lett. 2007, 9, 85–87.
ˇ
12. Kotrusz, P.; Toma, S. L -Proline catalyzed Michael additions of thiophenols
to a,b-unsaturated compounds, particularly a-enones, in the ionic liquid
[bmim]PF6. Molecules 2006, 11, 197–205.