Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins

Article abstract of DOI:10.1080/17415993.2017.1369541

Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins is described. A series of 2-((2-nitro-1-arylethyl)thio)pyrimidines were efficiently synthesized. The protocol has advantages of wide range of substituents tolerance, no catalyst, additives and bases, mild condition, and high yield. The method can also extend to gram scale.

Full text of DOI:10.1080/17415993.2017.1369541

Journal of Sulfur Chemistry
ISSN: 1741-5993 (Print) 1741-6000 (Online) Journal homepage: http://www.tandfonline.com/loi/gsrp20
Catalyst-free sulfa-Michael addition of
pyrimidine-2-thiol to nitroolefins
Zheng Li, Geyang Song, Jiaojiao He, Yan Du & Jingya Yang
To cite this article: Zheng Li, Geyang Song, Jiaojiao He, Yan Du & Jingya Yang (2017) Catalyst-
free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins, Journal of Sulfur Chemistry, 38:6,
686-698, DOI: 10.1080/17415993.2017.1369541
To link to this article: https://doi.org/10.1080/17415993.2017.1369541
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JOURNAL OF SULFUR CHEMISTRY, 2017
VOL. 38, NO. 6, 686–698
https://doi.org/10.1080/17415993.2017.1369541
Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to
nitroolefins
Zheng Li, Geyang Song, Jiaojiao He, Yan Du and Jingya Yang
College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, People’s Republic of
China
ABSTRACT
ARTICLE HISTORY
Catalyst-freesulfa-Michaeladditionofpyrimidine-2-thioltonitroolefins Received 18 April 2017
Accepted 12 August 2017
is described. A series of 2-((2-nitro-1-arylethyl)thio)pyrimidines were
efficiently synthesized. The protocol has advantages of wide range of
substituents tolerance, no catalyst, additives and bases, mild condi-
tion, and high yield. The method can also extend to gram scale.
KEYWORDS
Nitroolefin;
pyrimidine-2-thiol;
sulfa-Michael addition;
2
-((2-nitro-1-
arylethyl)thio)pyrimidine;
synthesis
1. Introduction
Sulfa-Michael addition is one of the most powerful methodologies for the construction
of sulfur–carbon bond and for the synthesis of important sulfur-containing compounds,
which are ubiquitously found in various organisms and play important roles in biological
and medicinal chemistry [1–8]. The reported sulfa-Michael addition generally uses thi-
ols as Michael donors to react with various Michael acceptors, such as α,β-unsaturated
ketones [9–13], esters [14,15], amides [16], acids [17], nitriles [18], sulfones [19] and sul-
fonates [20], activated alkenes [21], and dienes [22]. Among Michael acceptors, nitroolefins
CONTACT Zheng Li
lizheng@nwnu.edu.cn
College of Chemistry and Chemical Engineering, Northwest
Normal University, Lanzhou, Gansu 730070, People’s Republic of China
This article makes reference to supplementary material available on the publisher’s website at https://doi.org/10.1080/
7415993.2017.1369541
1
©
2017 Informa UK Limited, trading as Taylor & Francis Group

JOURNAL OF SULFUR CHEMISTRY
687
are very attractive because of the strong electron-withdrawing capacity of the nitro group
23–26]. Meanwhile, the nitro group can be easily converted into various useful func-
[
tion groups, such as ketone, nitrile, nitrile oxide, and amino groups [27–32]. Additionally,
the sulfa-Michael addition products, β-nitro sulfides are particularly versatile in synthetic
chemistry since they can undergo a series of attractive transformations to provide diverse
functionality [33–36]. However, the reports for sulfa-Michael addition of nitroolefins have
mainly focused on employing aryl thiols [37–40], alkyl thiols [39,40], benzyl thiols [41,42],
thioaectic acids [43], and lithium thiolates [44] as Michael donors. To the best of our
knowledge, very scarce reports have been described using heteroaromatic thiols such as
Michael donors. In addition, some reported methods usually require expensive catalysts
and harsh reaction conditions. Therefore, it is necessary to explore some methods suitable
to heteroaromatic thiols under mild conditions.
In this paper, we report a catalyst-free method for sulfa-Michael addition using het-
eroaromatic thiol, pyrimidine-2-thiol, as Michael donors and nitroolefins as Michael
acceptors under mild conditions.
2. Results and discussion
Initially, in order to investigate the sulfa-Michael additions of nitroolefins with het-
eroaromatic thiols, nitrostyrene (1a) was selected as the model substrate to react with
pyrimidine-2-thiol in acetonitrile at room temperature. It was found that the desired
sulfa-Michael addition product, 2-((2-nitro-1-phenylethyl)thio)pyrimidine (2a), could be
isolated in 79% yield (Table 1, Entry 1). This result implied that the model reaction could
be carried out under catalyst-free and mild condition. In order to improve the reaction
Table 1. The effect of reaction conditions on the yield of 2aa.
Entry
Solvent
MeCN
DMSO
DMF
Temperature (°C)
Time (h)
Catalyst
Yield (%)b
1
2
3
4
5
6
7
8
9
R.T.
R.T.
R.T.
R.T.
R.T.
R.T.
R.T.
R.T.
30
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
1.5
3
–
–
–
–
–
–
–
–
–
–
–
–
–
79
78
75
81
83
85
70
92
88
70
88
81
75
Trace
Trace
Trace
EtOH
1,4-dioxane
CH2ClCH2Cl
CHCl3
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
10
11
12
13
14
15
16
40
R.T.
R.T.
R.T.
R.T.
R.T.
R.T.
4.5
0.5
0.5
0.5
KOH
Cs2CO3
DBU
aReaction condition: 1a (0.1 mmol) and pyrimidine-2-thiol (0.1 mmol) in solvent (3 mL) for appropriate time at appropriate
temperature.
Isolated yield.
b

688
Z. LI ET AL.
yield, the model reaction was attempted under other conditions. It was found that sol-
vents had a certain effect on the yield of 2a. The reaction could be conducted in DMSO,
N,N-dimethylformamide, EtOH, 1,4-dioxane, 1,2-dichloroethane, CHCl and CH Cl ,
3
,
2
2
and give 2a in good to high yield (Table 1, Entries 2–8). Among them, the highest yield
for 2a was obtained by using CH Cl as the solvent (Table 1, Entry 8). Elevated tempera-
2
2
ture from room temperature to 40°C was a disadvantage to the reaction yield presumably
due to the increase in by-products (Table 1, Entries 9, 10). Furthermore, prolonged reac-
tion time did not have an obvious effect on the reaction yield (Table 1, Entries 11–13). In
addition, the uses of 0.2 equiv of bases as catalysts could inhibit the reaction, and lead to
only trace amount of the observed product (Table 1, Entries 14–16). The main reason may
be that the existence of bases could cause the decomposition of pyrimidine-2-thiol.
Based on the optimized conditions, the scope of sulfa-Michael addition of pyrimidine-
2-thiol to nitroolefins is evaluated, and the results are presented in Table 2. It was found
that the reactions using nitrostyrenes as substrates could tolerate a wide range of functional
groups including electron-donating and electron-withdrawing groups on the aromatic
Table 2. Scope of sulfa-Michael additions of pyrimidine-2-thiol to nitroolefinsa.
(
continued).

JOURNAL OF SULFUR CHEMISTRY
689
Table 2. Continued.
a
Reaction conditions: 1a (0.1 mmol) and pyrimidine-2-thiol (0.1 mmol) in CH2Cl2 (3 mL) for 0.5 h at room temperature.
Reaction time: 5 h.
Reaction conditions: 1a (0.1 mmol), pyrimidine-2-thiol (0.1 mmol) and DBU (0.1 mmol) in MeCN (3 mL) for 5 h at room
b
c
temperature.

690
Z. LI ET AL.
rings, and afford the corresponding sulfa-Michael addition products in good to high
yields. Nitrostyrenes bearing electron-donating groups (Me or MeO) at ortho-, meta-
and para- positions of aromatic rings could give very high yields (2b–2g). In contrast,
nitrostyrenes bearing electron-withdrawing groups (F, CF , Cl, Br, NO ) on the aromatic
3
2
rings gave slightly lower yields (2h–2s). Nitrostyrenes including disubstituted groups on
the aromatic rings was also a viable substrate for sulfa-Michael addition and afforded
the corresponding sulfur-containing compound in high yield (2g). The attempt for 1-(2-
nitrovinyl)naphthalene as a substrate succeeded under the condition of prolonged time
(
5 h) (2t). Nitroolefins including heteroaromatic rings, such as furyl and thienyl, could
also afford the corresponding sulfa-Michael addition products in high yield (2u, 2v).
The aliphatic nitroolefins, such as 3,3-dimethyl-1-nitrobut-1-ene, was also active for the
sulfa-Michael addition (2w). In addition, the sulfa-Michael addition using substituted
pyrimidine-2-thiol, such as 4,6-dimethylpyrimidine-2-thiol, as a Michael donor could also
be conducted. However, the reaction had to complete by using the 0.2 equiv of base,
such as DBU, as a catalyst and acetonitrile as solvent for prolonged time (5 h) (Scheme 1,
2x). The sulfa-Michael reactions for other types of heteroaromatic thiols were also tested.
The reaction of pyridine-2-thiol with 1a could give sulfa-Michael adduct in very high
yield (Scheme 2, 2y). However, the tested other heteroaromatic thiols, such as imidazole-
2
-thiol, 1,3,4-thiadiazole-2-thiol, benzo[d]oxazole-2-thiol and benzo[d]thiazole-2-thiol,
Scheme 1. The sulfa-Michael addition of 4,6-dimethylpyridine-2-thiol to 1a.
Scheme 2. The sulfa-Michael addition of pyridine-2-thiol to 1a.
Scheme 3. Gram-scale synthesis of 2a.

JOURNAL OF SULFUR CHEMISTRY
691
could not give corresponding sulfa-Michael addition products possibly because of different
electron effect.
It is worthy to mention that the reaction of 1a with pyrimidine-2-thiol could also be
performed on gram scale and give 2a in good yield (Scheme 3). The reaction of 1.5 g of 1a
with 1.1 g of pyrimidine-2-thiol in CH Cl (15 mL) was performed under the optimized
2
2
condition to give 2a in 65% (1.7 g) isolated yield. The success of this gram scale reaction
further showed the potency of optimized condition for the bulk processes.
3. Conclusion
In summary, an efficient method for the catalyst-free sulfa-Michael addition of heteroaro-
matic thiol, pyrimidine-2-thiol, to nitroolefins was developed. A series of 2-((2-nitro-1-
arylethyl)thio)pyrimidines were synthesized under mild conditions. This protocol can be
readily extended to gram scale and applied to useful industrial synthesis.
4
. Experimental
.1. General
1H NMR and 13C NMR spectra were recorded on Mercury-400 BB or Mercury-600 BB
instrument using CDCl as the solvent and Me Si as the internal standard. Elemental anal-
4
3
4
yses were performed on a Vario El Elemental Analysis instrument. Melting points were
observed in an electrothermal melting point apparatus. Pyrimidine-2-thiol was purchased
from Aldrich (98%). Nitroolefins were synthesized by reactions of various aldehydes with
nitromethane in the solution of HOAc–NH OAc under reflux condition.
4
4
.2. The general procedure for the preparation of 2-((2-nitro-1-arylethyl)thio)
pyrimidines
The mixture of nitroolefins (0.1 mmol) and pyrimidine-2-thiol (0.1 mmol, 11.2 mg) in
3
mL of methylene chloride was stirred at room temperature for 0.5 h. The progress of the
reaction was monitored by TLC. After the completion of reaction, the resulting mixture was
concentrated under reduced pressure. The residue was isolated by column chromatography
using petroleum ether and ethyl acetate (v/v 6:1) as eluent to give pure products.
4
.2.1. 2-((1-Phenyl-2-nitroethyl)thio)pyrimidine (2a)
1
Pale yellow solid. Mp: 90–91°C. H NMR (600 MHz, CDCl ) δ 8.58 (d, J = 4.8 Hz, 2H,
3
PyH), 7.43 (d, J = 7.6 Hz, 2H, ArH), 7.37 (t, J = 7.5 Hz, 2H, ArH), 7.32 (t, J = 7.3 Hz,
1
H, ArH), 7.05 (t, J = 4.9 Hz, 1H, PyH), 5.59 (dd, J = 10.4, 5.2 Hz, 1H, CH), 5.21 (dd,
13
J = 13.2, 5.2 Hz, 1H, CH ), 4.97 (dd, J = 13.2, 10.4 Hz, 1H, CH ). C NMR (150 MHz,
2
2
CDCl ) δ 170.2, 157.7, 135.5, 129.1, 128.8, 128.0, 117.4, 78.2, 45.6. Anal. Calcd for
3
C H N O S: C, 55.16; H, 4.24; N, 16.08. Found: C, 55.07; H, 4.22; N, 16.12.
1
2
11
3
2
4
.2.2. 2-((1-(2-Tolyl)-2-nitroethyl)thio)pyrimidine (2b)
1
Deep yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.7 Hz, 2H, PyH), 7.36 (t,
3
J = 3.9 Hz, 1H, ArH), 7.23 (t, J = 4.7 Hz, 3H, ArH), 7.06 (t, J = 4.8 Hz, 1H, PyH), 5.87
(
dd, J = 10.6, 5.3 Hz, 1H, CH), 5.22 (dd, J = 13.4, 5.3 Hz, 1H, CH ), 5.08 (dd, J = 13.4,
2

692
Z. LI ET AL.
1
3
1
1
5
0.6 Hz, 1H, CH ), 2.49 (s, 3H, CH ). C NMR (150 MHz, CDCl ) δ 170.5, 157.8, 137.0,
2 3 3
33.2, 131.3, 128.56, 126.7, 126.2, 117.4, 77.2, 41.3, 19.4. Anal. Calcd for C H N O S: C,
6.71; H, 4.76; N, 15.26. Found: C, 56.80; H, 4.77; N, 15.21.
1
3
13
3
2
4
.2.3. 2-((1-(3-Tolyl)-2-nitroethyl)thio)pyrimidine (2c)
1
Light yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH), 7.26 (t ,
3
J = 7.3 Hz, 1H, ArH), 7.22 (d, J = 8.3 Hz, 2H, ArH), 7.14 (d, J = 7.4 Hz, 1H, ArH), 7.06
(
t, J = 4.8 Hz, 1H, PyH), 5.57 (dd, J = 10.5, 5.2 Hz, 1H, CH), 5.20 (dd, J = 13.2, 5.2 Hz,
1
3
1
H, CH ), 4.96 (dd, J = 13.2, 10.5 Hz, 1H, CH ), 2.36 (s, 3H, CH ). C NMR (150 MHz,
2
2
3
CDCl ) δ 170.3, 157.7, 138.9, 135.3, 129.6, 129.0, 128.7, 124.9, 117.4, 78.1, 45.6, 21.4. Anal.
3
Calcd for C H N O S: C, 56.71; H, 4.76; N, 15.26. Found: C, 56.62; H, 4.75; N, 15.30.
1
3
13
3
2
4
.2.4. 2-((1-(4-Tolyl)-2-nitroethyl)thio)pyrimidine (2d)
1
White solid. Mp:148–149°C. H NMR (400 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH),
3
7
.31 (d, J = 8.1 Hz, 2H, ArH), 7.18 (d, J = 8.0 Hz, 2H, ArH), 7.06 (t, J = 4.9 Hz, 1H,
PyH), 5.57 (dd, J = 10.6, 5.1 Hz, 1H, CH), 5.21 (dd, J = 13.1, 5.1 Hz, 1H, CH ), 4.95 (dd,
2
1
3
J = 13.1, 10.6 Hz, 1H, CH ), 2.34 (s, 3H, CH ). C NMR (100 MHz, CDCl ) δ 170.4,
2
3
3
1
57.7, 138.7, 132.3, 129.8, 127.8, 117.3, 78.2, 45.4, 21.2. Anal. Calcd for C H N O S: C,
13 13 3 2
56.71; H, 4.76; N, 15.26. Found: C, 56.80; H, 4.78; N, 15.28.
4
.2.5. 2-((1-(3-Methoxyphenyl)-2-nitroethyl)thio)pyrimidine (2e)
1
Yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH), 7.29 (t,
3
J = 8.0 Hz, 1H, ArH), 7.06 (t, J = 4.9 Hz, 1H, PyH), 7.01 (d, J = 7.7 Hz, 1H, ArH), 6.96
(
s, 1H, ArH), 6.87 (dd, J = 8.2, 2.1 Hz, 1H, ArH), 5.58 (dd, J = 10.4, 5.3 Hz, 1H, CH), 5.20
(
dd, J = 13.3, 5.3 Hz, 1H, CH ), 4.96 (dd, J = 13.3, 10.4 Hz, 1H, CH ), 3.81 (s, 3H, OCH ).
2
2
3
1
3
C NMR (150 MHz, CDCl ) δ 170.2, 160.0, 157.7, 136.9, 130.2, 120.0, 117.4, 114.2, 113.9,
3
7
8.1, 55.3, 45.6. Anal. Calcd for C H N O S: C, 53.60; H, 4.50; N, 14.42. Found: C, 53.49;
13 13 3 3
H, 4.48; N, 14.46.
4
.2.6. 2-((1-(4-Methoxyphenyl)-2-nitroethyl)thio)pyrimidine (2f)
1
White solid. Mp: 140–141°C. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH),
3
7
.35 (d, J = 8.6 Hz, 2H, ArH), 7.06 (t, J = 4.9 Hz, 1H, PyH), 6.89 (d, J = 8.7 Hz, 2H,
ArH), 5.56 (dd, J = 10.6, 5.1 Hz, 1H, CH), 5.21 (dd, J = 13.1, 5.1 Hz, 1H, CH ), 4.92 (dd,
2
1
3
J = 13.1, 10.6 Hz, 1H, CH ), 3.80 (s, 3H, OCH ). C NMR (100 MHz, CDCl ) δ 170.4,
2
3
3
1
59.8, 157.7, 129.1, 127.2, 117.3, 114.5, 78.3, 55.3, 45.2. Anal. Calcd for C H N O S: C,
13 13 3 3
53.60; H, 4.50; N, 14.42. Found: C, 53.72; H, 4.50; N, 14.37.
4
.2.7. 2-((1-(2,5-Dimethoxyphenyl)-2-nitroethyl)thio)pyrimidine (2g)
1
Yellow liquid. H NMR (600 MHz, CDCl ) δ 8.58 (d, J = 4.8 Hz, 2H, PyH), 6.99 (t,
3
J = 4.8 Hz, 1H, PyH), 6.95 (d, J = 2.8 Hz, 1H, ArH), 6.81–6.86 (m, 2H, ArH), 5.87 (dd,
J = 9.7, 5.8 Hz, 1H, CH), 5.15 (dd, J = 13.1, 9.7 Hz, 1H, CH ), 5.07 (dd, J = 13.1, 5.8 Hz,
2
1
3
1
H, CH ) 3.86 (s, 3H, OCH ), 3.76 (s, 3H, OCH ). C NMR (150 MHz, CDCl ) δ 171.0,
2 3 3 3
1
57.6, 153.5, 151.7, 124.8, 117.1, 115.8, 114.4, 112.5, 77.3, 56.3, 55.7, 42.3. Anal. Calcd for
C H N O S: C, 52.33; H, 4.71; N, 13.08. Found: C, 52.22; H, 4.69; N, 13.12.
1
4
15
3
4

JOURNAL OF SULFUR CHEMISTRY
693
4
.2.8. 2-((1-(2-Fluorophenyl)-2-nitroethyl)thio)pyrimidine (2h)
1
Light yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.8 Hz, 2H, PyH), 7.45
3
(
t, J = 7.4 Hz, 1H, ArH), 7.33 (q, J = 6.7 Hz, 1H), 7.09–7.16 (m, 2H, ArH), 7.06 (t,
J = 4.8 Hz, 1H, PyH), 5.89 (dd, J = 10.1, 5.4 Hz, 1H, CH), 5.17 (dd, J = 13.5, 5.4 Hz,
1
3
1
1
H, CH ), 5.06 (dd, J = 13.5, 10.1 Hz, 1H , CH ). C NMR (150 MHz, CDCl ) δ 17.0,
2
2
3
61.6, 159.9, 157.8, 130.6, 130.5, 129.6, 124.7, 117.4, 116.3, 116.2, 40.0. Anal. Calcd for
C H FN O S: C, 51.61; H, 3.61; N, 15.05. Found: C, 51.54; H, 3.59; N, 15.00.
1
2
10
3
2
4
.2.9. 2-((1-(3-Fluorophenyl)-2-nitroethyl)thio)pyrimidine (2i)
1
Yellow liquid. H NMR (600 MHz, CDCl ) δ 8.58 (d, J = 4.9 Hz, 2H, PyH), 7.32–7.36 (m,
3
1
1
5
1
H, ArH), 7.22 (d, J = 7.7 Hz, 1H, ArH), 7.16 (d, J = 9.4 Hz, 1H, ArH), 7.07 (t, J = 4.8 Hz,
H, PyH), 7.01–7.04 (m, 1H, ArH), 5.59 (dd, J = 10.4, 5.2 Hz, 1H, CH), 5.19 (dd, J = 13.4,
1
3
.2 Hz, 1H, CH ), 4.94 (dd, J = 13.4, 10.4 Hz, 1H, CH ). C NMR (150 MHz, CDCl ) δ
2
2
3
69.8, 163.7, 162.0, 157.8, 138.0, 130.8, 123.6, 117.6, 115.8, 115.2, 77.9, 45.0. Anal. Calcd
for C H FN O S: C, 51.61; H, 3.61; N, 15.05. Found: C, 51.68; H, 3.62; N, 15.11.
1
2
10
3
2
4
.2.10. 2-((1-(4-Fluorophenyl)-2-nitroethyl)thio)pyrimidine (2j)
1
Pale yellow solid. Mp: 103–105°C. H NMR (600 MHz, CDCl ) δ 8.58 (d, J = 4.9 Hz, 2H,
3
PyH), 7.41 (dd, J = 8.6, 5.2 Hz, 2H), 7.04–7.07 (m, 3H, ArH, PyH), 5.59 (dd, J = 10.5,
5
.2 Hz, 1H, CH), 5.21 (dd, J = 13.3, 5.2 Hz, 1H, CH ), 4.91 (dd, J = 13.3, 10.5 Hz, 1H,
13
2
CH ). C NMR (150 MHz, CDCl ) δ 169.9, 163.5, 161.9, 157.8, 131.4, 129.8, 117.5, 116.2,
2
3
7
8.1, 44.9. Anal. Calcd for C H FN O S: C, 51.61; H, 3.61; N, 15.05. Found: C, 51.71; H,
12 10 3 2
3
.60; N, 14.99.
4
.2.11. 2-((1-(4-(Trifluoromethyl)phenyl)-2-nitroethyl)thio)pyrimidine (2k)
1
Pale yellow solid. Mp: 143–144°C. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H,
3
PyH), 7.64 (d, J = 8.2 Hz, 2H, ArH), 7.57 (d, J = 8.2 Hz, 2H, ArH), 7.09 (t, J = 4.9 Hz,
1
H, PyH), 5.67 (dd, J = 10.4, 5.2 Hz, 1H, CH), 5.21 (dd, J = 13.6, 5.2 Hz, 1H, CH ), 4.98
13
2
(
dd, J = 13.6, 10.4 Hz, 1H, CH ). C NMR (150 MHz, CDCl ) δ 169.6, 157.8, 139.8, 130.8,
2
3
1
28.5, 126.2, 126.1, 126.1, 126.1, 117.7, 110.0, 77.7, 45.0. Anal. Calcd for C H F N O S:
13 10 3 3 2
C, 47.42; H, 3.06; N, 12.76. Found: C, 47.35; H, 3.08; N, 12.80.
4
.2.12. 2-((1-(2-Chlorophenyl)-2-nitroethyl)thio)pyrimidine (2l)
1
Light yellow liquid. H NMR (600 MHz, CDCl ) δ 8.57 (d, J = 4.9 Hz, 2H, PyH), 7.48
3
(
dd, J = 7.1, 2.1 Hz, 1H, ArH), 7.43 (d, J = 4.6 Hz, 1H, ArH), 7.27 (t, J = 3.7 Hz, 2H,
ArH), 7.05 (t, J = 4.7 Hz, 1H, PyH), 6.14 (dd, J = 9.7, 5.7 Hz, 1H, CH), 5.18 (dd, J = 13.6,
1
3
5
.7 Hz, 1H, CH ), 5.13 (dd, J = 13.6, 9.7 Hz, 1H, CH ). C NMR (150 MHz, CDCl )
2
2
3
δ 169.9, 157.8, 134.2, 133.2, 130.5, 129.9, 128.8, 127.4, 117.5, 76.8, 42.5. Anal. Calcd for
C H ClN O S: C, 48.74; H, 3.41; N, 14.21. Found: C, 48.67; H, 3.39; N, 14.18.
1
2
10
3
2
4
.2.13. 2-((1-(3-Chlorophenyl)-2-nitroethyl)thio)pyrimidine (2m)
1
Yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH), 7.44 (s, 1H,
3
ArH), 7.30–7.33 (m, 3H, ArH), 7.08 (t, J = 4.9 Hz, 1H, PyH), 5.59 (dd, J = 10.4, 5.2 Hz,
1
3
1
H, CH), 5.19 (dd, J = 13.5, 5.2 Hz, 1H, CH ), 4.94 (dd, J = 13.5, 10.4 Hz, 1H, CH ).
C
2
2
NMR (150 MHz, CDCl ) δ 169.8, 157.8, 137.7, 134.9, 130.4, 129.0, 128.3, 126.1, 117.6, 77.8,
3

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4
5.0. Anal. Calcd for C H ClN O S: C, 48.74; H, 3.41; N, 14.21. Found: C, 48.81; H, 3.40;
12 10 3 2
N, 14.26.
4
.2.14. 2-((1-(4-Chlorophenyl)-2-nitroethyl)thio)pyrimidine (2n)
1
Pale yellow solid. Mp: 120–122°C. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H,
3
PyH), 7.36 (q, J = 8.8 Hz, 4H, ArH), 7.08 (t, J = 4.9 Hz, 1H, PyH), 5.59 (dd, J = 10.4,
5
.2 Hz, 1H, CH), 5.19 (dd, J = 13.4, 5.2 Hz, 1H, CH ), 4.93 (dd, J = 13.4, 10.4 Hz, 1H,
13
2
CH ). C NMR (150 MHz, CDCl ) δ 169.9, 157.8, 134.7, 130.2, 129.4, 129.3, 117.5, 77.9,
2
3
4
4.9. Anal. Calcd for C H ClN O S: C, 48.74; H, 3.41; N, 14.21. Found: C, 48.69; H, 3.43;
12 10 3 2
N, 14.24.
4
.2.15. 2-((1-(2-Bromophenyl)-2-nitroethyl)thio)pyrimidine (2o)
1
Deep yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH), 7.63
3
(
7
d, J = 8.0 Hz, 1H, ArH), 7.48 (d, J = 7.7 Hz, 1H, ArH), 7.33 (t, J = 7.4 Hz, 1H, ArH),
.19 (t, J = 7.7 Hz, 1H, ArH), 7.07 (t, J = 4.9 Hz, 1H, PyH), 6.14 (dd, J = 9.6, 5.8 Hz, 1H,
1
3
CH), 5.17 (dd, J = 13.7, 5.8 Hz, 1H, CH ), 5.12 (dd, J = 13.6, 9.7 Hz, 1H, CH ). C NMR
2
2
(
150 MHz, CDCl ) δ 170.0, 157.8, 134.7, 133.9, 130.1, 128.7, 128.0, 124.8, 117.5, 76.8, 44.8.
3
Anal. Calcd for C H BrN O S: C, 42.37; H, 2.96; N, 12.35. Found: C, 42.47; H, 2.97; N,
1
2
10
3
2
1
2.40.
4
.2.16. 2-((1-(4-Bromophenyl)-2-nitroethyl)thio)pyrimidine (2p)
1
Pale yellow solid. Mp: 136–137°C. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H,
3
PyH), 7.51 (d, J = 8.4 Hz, 2H, ArH), 7.32 (d, J = 8.5 Hz, 2H, ArH), 7.08 (t, J = 4.8 Hz,
1
H, PyH), 5.57 (dd, J = 10.5, 5.1 Hz, 1H, CH), 5.20 (dd, J = 13.6, 5.1 Hz, 1H, CH ), 4.92
13
2
(
dd, J = 13.6, 10.5 Hz, 1H, CH ). C NMR (150 MHz, CDCl ) δ 169.8, 157.8, 134.7, 132.3,
2
3
1
29.6, 122.9, 117.5, 77.8, 45.0. Anal. Calcd for C H BrN O S: C, 42.37; H, 2.96; N, 12.35.
12 10 3 2
Found: C, 42.31; H, 2.95; N, 12.31.
4
.2.17. 2-((1-(2-Nitrophenyl)-2-nitroethyl)thio)pyrimidine (2q)
1
Yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H, PyH), 7.67 (d,
3
J = 8.0 Hz, 1H, ArH), 7.48 (d, J = 7.7 Hz, 1H, ArH), 7.33 (t, J = 7.6 Hz, 1H, ArH), 7.19
(
(
t, J = 7.7 Hz, 1H, ArH), 7.06 (t, J = 4.9 Hz, 1H), 6.14 (dd, J = 9.6, 5.8 Hz, 1H, CH), 5.18
13
dd, J = 13.7, 5.8 Hz, 1H, CH ), 5.12 (dd, J = 13.7, 9.6 Hz, 1H, CH ). C NMR (150 MHz,
2
2
CDCl ) δ 169.4, 157.7, 134.1, 133.4, 132.0, 130.1, 129.3, 124.9, 117.5, 77.5, 41.0. Anal. Calcd
3
for C H N O S: C, 47.06; H, 3.29; N, 18.29. Found: C, 46.94; H, 3.31; N, 18.36.
1
2
10
4
4
4
.2.18. 2-((1-(3-Nitrophenyl)2-nitroethyl)thio)pyrimidine (2r)
1
Yellow liquid. H NMR (600 MHz, CDCl ) δ 8.60 (d, J = 4.9 Hz, 2H, PyH), 8.36 (t,
3
J = 1.8 Hz, 1H, ArH), 8.21 (d, J = 8.2 Hz, 1H, ArH), 7.80 (d, J = 7.7 Hz, 1H, ArH), 7.58 (t,
J = 8.0 Hz, 1H, ArH), 7.11 (t, J = 4.9 Hz, 1H, PyH), 5.73 (dd, J = 10.4, 5.2 Hz, 1H, CH),
1
3
5
.23 (dd, J = 13.7, 5.2 Hz, 1H, CH ), 5.02 (dd, J = 13.7, 10.4 Hz, 1H, CH ). C NMR
2
2
(150 MHz, CDCl ) δ 169.2, 157.9, 148.5, 138.2, 134.0, 130.2, 123.7, 123.2, 117.8, 77.5, 44.8.
3
Anal. Calcd for C H N O S: C, 47.06; H, 3.29; N, 18.29. Found: C, 47.13; H, 3.30; N,
1
2
10
4
4
1
8.33.

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4
.2.19. 2-((1-(4-Nitrophenyl)-2-nitroethyl)thio)pyrimidine (2s)
1
Yellow solid. Mp: 103–104°C. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.7 Hz, 2H, PyH),
3
8
.23 (d, J = 8.5 Hz, 2H, ArH), 7.64 (d, J = 8.6 Hz, 2H, ArH), 7.10 (t, J = 4.7 Hz, 1H,
PyH), 5.71 (dd, J = 10.4, 5.2 Hz, 1H, CH), 5.21 (dd, J = 13.7, 5.2 Hz, 1H, CH ), 4.99 (dd,
2
1
3
J = 13.7, 10.4 Hz, 1H, CH ). C NMR (150 MHz, CDCl ) δ 169.2, 157.9, 148.0, 143.2,
2
3
129.1, 124.3, 117.8, 77.5, 44.8. Anal. Calcd for C H N O S: C, 47.06; H, 3.29; N, 18.29.
12 10 4 4
Found: C, 47.18; H, 3.28; N, 18.24.
4
.2.20. 2-((1-(Naphthalene-1-yl)-2-nitroethyl)thio)pyrimidine (2t)
1
White solid. Mp: 86–88°C. H NMR (600 MHz, CDCl ) δ 8.62 (d, J = 4.8 Hz, 2H), 8.23 (d,
3
J = 8.5 Hz, 1H), 7.88 (d, J = 8.1 Hz, 1H), 7.84 (d, J = 8.2 Hz, 1H), 7.62 (d, J = 7.2 Hz,
1
H), 7.58 (t, J = 7.7 Hz, 1H), 7.53 (t, J = 7.5 Hz, 1H), 7.46 (t, J = 7.7 Hz, 1H), 7.08 (t,
13
J = 4.9 Hz, 1H), 5.32–5.26 (m, 3H, CH, CH ). C NMR (150 MHz, CDCl ) δ 170.33,
2
3
1
57.85, 134.19, 130.94, 130.89, 129.57, 129.13, 126.97, 126.24, 125.21, 122.83, 117.48, 77.24,
4
0.95. Anal. Calcd for C H N O S: C, 61.72; H, 4.21; N, 13.50. Found: C, 61.66; H, 4.23;
1
6
13
3
2
N, 13.55.
4
.2.21. 2-((1-(2-Furanyl)-2-nitroethyl)thio)pyrimidine (2u)
1
Deep yellow liquid. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.8 Hz, 2H, PyH), 7.40 (s,
3
1
1
H, FuH), 7.07 (t, J = 4.8 Hz, 1H, PyH), 6.41 (d, J = 3.1 Hz, 1H, FuH), 6.35 (t, J = 2.3 Hz,
H, FuH), 5.81 (dd, J = 9.1, 6.0 Hz, 1H, CH), 5.06 (dd, J = 11.5, 6.0 Hz, 1H, CH ), 5.04
2
1
3
(
dd, J = 11.5, 9.1 Hz, 1H). C NMR (150 MHz, CDCl ) δ 169.7, 157.8, 148.3, 143.3, 117.5,
3
1
10.8, 109.0, 76.1, 39.3. Anal. Calcd for C H N O S: C, 47.80; H, 3.61; N, 16.72. Found:
10 9 3 3
C, 47.72; H, 3.59; N, 16.79.
4
.2.22. 2-((1-(2-Thiophenyl)-2-nitroethyl)thio)pyrimidine (2v)
1
Yellow solid. Mp: 99–101°C. H NMR (600 MHz, CDCl ) δ 8.59 (d, J = 4.9 Hz, 2H), 7.35
3
(
(
4
1
1
d, J = 9.2 Hz, 1H, ThH), 7.24–7.26 (m, 1H, ThH), 7.13–7.14 (m, 1H, ThH), 7.05–7.07
m, 1H, PyH), 5.75 (dd, J = 10.3, 5.1 Hz, 1H, CH), 5.18 (dd, J = 13.1, 5.1 Hz, 1H, CH ),
2
1
3
.93 (dd, J = 13.1, 10.3 Hz, 1H, CH ). C NMR (150 MHz, CDCl ) δ 170.1, 157.7, 135.7,
2
3
27.1, 126.7, 123.7, 117.4, 78.3, 41.0. Anal. Calcd for C H N O S : C, 44.93; H, 3.39; N,
1
0
9
3
2 2
5.72. Found: C, 45.04; H, 3.40; N, 15.68.
4
.2.23. 2-((3,3-Dimethyl-1-nitrobutan-2-yl)thio)pyrimidine (2w)
1
White solid. Mp: 103–104°C. H NMR (400 MHz, CDCl ) δ 8.52 (d, J = 4.9 Hz, 2H, PyH),
3
7
.00 (s, 1H, PyH), 4.85 (dd, J = 13.0, 5.4 Hz, 1H, CH), 4.79 (dd, J = 7.7, 5.4 Hz, 1H, CH ),
2
13
4
.60 (dd, J = 13.0, 7.7 Hz, 1H, CH ), 1.13 (s, 9H, CH ). C NMR (100 MHz, CDCl ) δ
2
3
3
1
71.13, 157.58, 117.26, 77.48, 52.53, 35.10, 27.74. Anal. Calcd for C H N O S: C, 49.77;
10 15 3 2
H, 6.27; N, 17.41. Found: C, 49.88; H, 6.25; N, 17.35.
4
.2.24. 4,6-Dimethyl-2-((2-nitro-1-phenylethyl)thio)pyrimidine (2x)
1
Colorless oil. H NMR (400 MHz, CDCl ) δ 7.43 (dd, J = 8.1, 1.4 Hz, 2H, ArH), 7.35 (d,
3
J = 7.4 Hz, 3H, ArH), 6.77 (s, 1H, PyH), 5.61 (dd, J = 10.4, 5.0 Hz, 1H, CH), 5.22 (dd,
1
3
J = 13.1, 5.0 Hz, 1H, CH ), 4.95 (dd, J = 13.0, 10.4 Hz, 1H, CH ), 2.43 (s, 6H, CH ). C
2
2
3
NMR (150 MHz, CDCl ) δ 168.89, 167.64, 135.84, 129.03, 128.59, 127.99, 116.53, 78.44,
3

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5.61, 23.84. Anal. Calcd for C H N O S: C, 58.11; H, 5.23; N, 14.52. Found: C, 58.02;
14 15 3 2
H, 5.26; N, 14.57.
4
.2.25. 2-((1-Phenyl-2-nitroethyl)thio)pyridine (2y)
1
White solid. Mp: 86–88°C. H NMR (600 MHz, CDCl ) δ 8.51 (dd, J = 4.9, 0.8 Hz, 1H,
3
PyH), 7.51–7.52 (m, 1H, PyH), 7.43 (d, J = 7.2 Hz, 2H, ArH), 7.37 (t, J = 7.4 Hz, 2H,
ArH), 7.32 (t, J = 7.3 Hz, 1H, PyH), 7.15 (d, J = 8.0 Hz, 1H, PyH), 7.06 (dd, J = 6.9,
5
4
1
.9 Hz, 1H, PyH), 5.70 (dd, J = 10.5, 5.1 Hz, 1H, CH), 5.25 (dd, J = 13.3, 5.1 Hz, 1H, CH ),
13
2
.95 (dd, J = 13.3, 10.5 Hz, 1H, CH ). C NMR (150 MHz, CDCl ) δ 156.6, 149.9, 136.4,
2
3
36.1, 129.1, 128.6, 127.9, 122.3, 120.4, 78.4, 44.7. Anal. Calcd for C H N O S: C, 59.98;
13 12 2 2
H, 4.65; N, 10.76. Found: C, 60.07; H, 4.62; N, 10.80.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
The authors thank the National Natural Science Foundation of China [21462038, 21362034] and Key
Laboratory of eco-environment Related Polymer Materials for Ministry of Education of the People’s
Republic of China for the financial support of this work.
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