Direct synthesis of α-ketothioamides from aryl methyl ketones and amines via I2-promoted sp3 C-H functionalization

Article abstract of DOI:10.1016/j.tet.2014.05.045

A domino reaction that involves the formation of CS and C-N bonds in one process via sp³ C-H functionalization strategy has been developed. This reaction affords an efficient and direct method for the synthesis of α-ketothioamides from aryl met

Full text of DOI:10.1016/j.tet.2014.05.045

Tetrahedron 70 (2014) 4645e4651
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Direct synthesis of
a
-ketothioamides from aryl methyl ketones and
amines via I2-promoted sp3 CeH functionalization
*
Hong-Zheng Li, Wei-Jian Xue, An-Xin Wu
Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
a r t i c l e i n f o
a b s t r a c t
A domino reaction that involves the formation of C]S and CeN bonds in one process via sp3 CeH
functionalization strategy has been developed. This reaction affords an efficient and direct method for
Article history:
Received 15 March 2014
Received in revised form 1 May 2014
Accepted 8 May 2014
the synthesis of
a-ketothioamides from aryl methyl ketones, amines, and sodium hydrosulfide under the
promotion of iodine.
Available online 20 May 2014
Ó 2014 Elsevier Ltd. All rights reserved.
Keywords:
Domino reaction
sp3 CeH functionalization
a
-Ketothioamides
1. Introduction
As an important transformation in synthetic chemistry, CeH
bond functionalization has been extensively pursued and widely
examined by organic chemists.1 In recent years, numerous methods
have been established for the conversion of a CeH bond to a CeZ
bond (such as CeC, CeN, and CeO), with particularly impressive
results achieved through transition-metal-catalyzed strategies.2 In
addition, iodine and iodides have emerged as effective mediums to
promote the CeH bond functionalization process and have been
utilized in the construction of diversified molecules.3 These
methods exhibit many advantages in providing metal-free, low
cost, and facile reaction conditions.4 Due to its efficacy in realizing
CeH bond functionalization, iodine has drawn general interests. In
our previous work, it was discovered that acetyl compounds, such
as acetophenone, could easily be activated by iodine to achieve the
sp3 CeH bond functionalization. Readily available acetophenone
was therefore utilized to construct various organic scaffolds in one
pot under facile conditions (Scheme 1).5 On account of the exten-
sive application of iodine in activating acetyl substrates to realize
the sp3 CeH bond functionalization, we tried to employ more ex-
amples to enrich this reaction system.
Scheme 1. The compounds derived from acetyl substrates in one pot.
applied to a wide range of fields, including organocatalysis,9 pep-
tide chemistry,10 and medical chemistry.11 So far, various methods
have been reported for the synthesis of thioamides, these methods
can be mainly classified into two categories according to their
synthetic strategy. One cluster of methodology emphasizes the use
of sulfur reagents to replace the oxygen atom of amide (Scheme 2,
(A)).12 Another cluster of methodology focuses attention on the
direct synthesis of thioamides from ketone, amine, and sulfur
powder (Scheme 2, (B)). Among these approaches, Will-
gerodteKindler reaction is widely accepted as the traditional
choice for the transformation of acetophenone to 2-
phenylacetamide.13 More recently, researchers have shifted their
Thioamides are an important class of functional skeletons,
which widely exist in bioactive molecules.6 They have been used as
valuable building blocks to construct sulfur-containing com-
pounds7 and natural products.8 Moreover, thioamides have been
* Corresponding author. Tel./fax: þ86 027 6786 7773; e-mail address: chwuax@
mail.ccnu.edu.cn (A.-X. Wu).
0040-4020/$ e see front matter Ó 2014 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2014.05.045

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H.-Z. Li et al. / Tetrahedron 70 (2014) 4645e4651
1.5 equiv led to the production of 2-morpholino-1-phenyl-2-
thioxoethanone (4a) in good yield (Table 1, Entry 10). However,
additional amounts of I2 failed to promote this reaction further
(Table 1, Entry 11). Next, 3a was replaced by various sulfur reagents,
such as sulfur sublimed, sulfur powder, and sodium sulfide (Table 1,
Entries 12e14), but all demonstrated dissatisfying results. Sodium
hydrosulfide was thus selected as the source of sulfur for this
conversion. The amount of sodium hydrosulfide was subsequently
investigated, where 2 equiv of NaSH$nH2O were confirmed as the
preferential ratio for this reaction. Following the experimental
optimizations, the suitable reaction conditions were determined as
acetophenone (1a, 1.0 mmol), morpholine (2a, 1.0 mmol), and
NaSH$nH2O (3a, 2.0 mmol) with I2 (1.5 mmol) at 120 ꢀC in the
presence of DMSO (Table 1, Entry 10).
Scheme 2. Strategies for the synthesis of thioamides and a-ketothioamides.
With the optimal conditions in hand, different sets of experi-
ments were performed to investigate the scope of this protocol. As
shown in Table 2, the reaction proceeded smoothly as acetophe-
none reacted with secondary amine (Table 2, 4aed) and aliphatic
amine (Table 2, 4e). Another set of examples were carried out be-
tween a wide range of substituted aryl methyl ketones and mor-
pholine, where it was found that the desired products could be
obtained in moderate to good yields (61e95%). It should be noted
that the electron-donating substituents attached to the phenyl
rings, such as para-Me, para-OMe, meta-OMe, and para-OEt
exhibited good reactivity in the reaction (Table 2, 4fei). The yields
showed a slight decrease while the electron-withdrawing groups,
such as F and Cl, were situated at the para-position of the phenyl
ring (4jek). In addition, the strong electron-withdrawing group
NO2 was also unfavorable for the transformation (4l). However, the
substitution of the benzene ring with aryls or heteroaryls, such as
phenyl (4m), naphthyl (4n and 4o), furanyl (4p), thiophenyl (4q) or
benzofuryl (4r), was found favorable for the reaction and excellent
attention to wider methods based on the WillgerodteKindler re-
action for the synthesis of thioamides and
-ketothioamides.14
a
However, neither the WillgerodteKindler reaction nor its analo-
gies have been able to achieve the direct and efficient conversion of
acetophenone to
promoted sp3 CeH functionalization strategy is reported for the
direct construction of -ketothioamides (Scheme 2, (C)).
a-ketothioamide. Herein, a highly efficient I2-
a
2. Results and discussion
The reaction of acetophenone (1a), morpholine (2a) and sodium
hydrosulfide (3a) with I2 at 120 ꢀC was initially selected as the
model reaction for optimization of the reaction conditions. First,
different solvents were screened, it was found that DMSO is the
most efficient solvent for the conversion (Table 1, Entries 1e6).
Higher and lower temperature were shown to decrease the yield of
the desired product, 120 ꢀC was thus selected as the optimum
temperature (Table 1, Entries 7e8). The target product could not be
obtained when the substrates were heated at 120 ꢀC in the absence
of I2 (Table 1, Entry 9), which implied that I2 played a crucial role in
the reaction. To our delight, an increase in the amount of I2 to
Table 2
Reaction scope of aryl methyl ketones and alkylaminesa
Table 1
Optimization of the reaction conditionsa
Entry
Solvent (3 mL)
I2 (equiv)
S source (equiv)
T (ꢀC)
Yield (%)d
1a
CH3OH
Glycol
CH3CN
DMF
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0
1.5
2.0
1.5
1.5
1.5
1.5
1.5
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
NaSH$nH2O
S
Reflux
120
Reflux
120
120
Reflux
100
140
120
120
120
31
33
de
35
72
de
57
68
de
86
78
<5
<5
46
80
84
2a
3a
4a
5a
DMSO
Dioxane
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
6a
7a
8a
9a
10a
11a
12a
13a
14a
15b
16c
120
120
120
120
S8
Na2S$9H2O
NaSH$nH2O
NaSH$nH2O
120
a
Reaction conditions: 1a (1.0 mmol), 2a (1.0 mmol) and 3a (2.0 mmol) with
a
Reaction conditions: 1a (1.0 mmol), 2a (1.0 mmol), and 3a (2.0 mmol) in 3 mL
I2 (1.5 mmol) in DMSO (3 mL) at 120oC for 5-10h.
solvent for 5 h.
b
c
b The compound 4s was prepared from 1-(9H-fluoren-2-yl)ethanone, but the
methylene was iodide by I2 and subsequently oxidized by DMSO (see details
in Supporting Information) .
Reaction was performed with 1.0 mmol of NaSH$nH2O for 5 h.
Reaction was performed with 1.5 mmol NaSH$nH2O for 5 h.
Isolated yields.
d
e
No desired product was obtained.

H.-Z. Li et al. / Tetrahedron 70 (2014) 4645e4651
4647
reactivity was achieved. On the other hand, 1-(9H-fluoren-2-yl)
ethanone provided the corresponding product in moderate yield
(4s). The structure of the product was confirmed by an X-ray
crystallographic study of 4q (Fig. 1).15
DMSO, the phenylglyoxal (1ab) or hemiacetal (1ac) could be ob-
tained in quantitative transformation (Scheme 3(b)). Then -iodo
acetophenone 1aa, 4-methoxyaniline 5f, and NaSH$nH2O were
subjected to the standard conditions for 3 h, and the desired
product (6f) was subsequently obtained in 83% yield. This indicated
a
that a-iodo acetophenone could be an important intermediate in
this reaction (Scheme 3(c)). To our satisfaction, the use of phenyl-
glyoxal (1ac) as a substitute for acetophenone led to the production
of the target product in 85% yield (Scheme 3(d)). This result
strongly proved that phenylglyoxal could also be a key in-
termediate in this reaction. Finally, 2-((4-methoxyphenyl)amino)-
1-phenylethanone
A
and
2-((4-methoxyphenyl)imino)-1-
phenylethanone B were synthesized to further study the reaction
details.17 To our surprise, both A and B could transform to 6f in good
yields under the standard conditions (Scheme 3(e), (f)). This sug-
gest that A and B were possible key intermediates.
Fig. 1. X-ray crystal structure of compound 4q.
Subsequently, various arylamines, which show weaker nucleo-
philicity were examined to further expand the scope of the sub-
strates. To our delight, aniline and the anilines with electron-
withdrawing substituents, such as F, Cl, and Br, proceeded
smoothly (Table 3, 6aed). Furthermore, the electron-donating
groups, including methyl, methoxyl, and isopropyl also furnished
the corresponding products in good yields (6eeg). The structure of
the target molecule was confirmed by the X-ray crystallographic
analysis of 6h (Fig. 2).15
Table 3
Reaction scope of arylaminesa
Scheme 3. Controlled experiments to prove the mechanism.
Based on the aforementioned results and our previous work,5
a proposed reaction mechanism was presented as follows using
acetophenone (1a) and 4-methoxyaniline (5f) as examples
(Scheme 4). First, 1a was substituted by iodine to afford 1aa. The
reaction subsequently underwent two possible pathways to ach-
ieve the transformation. In the main path A, 1aa was converted into
phenylglyoxal 1ab through Kornblum Oxidation. The in situ gen-
erated 1ab was immediately trapped by 5f to afford imine B. In path
B, a substitution occurred between 1aa and 5f to provide in-
termediate A, which was followed by iodination to afford A1. Next,
A1 underwent the oxidative dehydrogenation to generate imine B.18
Next, HSꢁ attacked intermediate B to afford D under an acid at-
mosphere. Finally, the target molecule 6f was then produced from
D via the oxidation of I2.19 In this process, the previously formed
byproduct HI could be oxidized by DMSO to regenerate I2
(Eq. 1).5a,m
a Reaction conditions: 1a (1.0 mmol), 5 (1.0 mmol), and 3a (2.0 mmol) with I2
(1.5 mmol) in DMSO (3 mL) at 120oC for 15-20h.
Fig. 2. X-ray crystal structure of compound 6h.
3. Conclusion
A series of control experiments were performed to gain some
insights into the reaction mechanism. Firstly, it was found that
a
-
In summary, an efficient I2-promoted sp3 CeH functionalization
iodo acetophenone (1aa) could form in 95% yield under the I2/CuO
strategy has been developed for the direct synthesis of
thioamides from readily available aryl methyl ketones and amines.
a-keto-
system (Scheme 3(a)).16 When acetophenone was added into the I2/

4648
H.-Z. Li et al. / Tetrahedron 70 (2014) 4645e4651
d
(ppm) 8.00 (d, J¼8.4 Hz, 2H), 7.65e7.60 (m, 1H), 7.50 (t, J¼7.8 Hz,
2H), 4.34 (t, J¼4.8 Hz, 2H), 3.91 (t, J¼4.8 Hz, 2H), 3.67e3.72 (m, 2H),
3.60 (t, J¼4.2 Hz, 2H); 13C NMR (100 MHz, CDCl3)
d (ppm) 195.6,
187.8, 134.4, 133.2, 129.8, 128.9, 66.4, 66.3, 51.9, 47.1; MS (EI): m/z
236.13 (Mþ1, 5.88), 235.09 (M, 53.20), 177.12 (34.09), 150.11 (5.27),
130.05 (100.00), 105.06 (86.03).
4.3.2. 1-Phenyl-2-(piperidin-1-yl)-2-thioxoethanone (4b).14b Yield
73%; light yellow solid; mp 70e74 ꢀC; IR (KBr): 2942, 2920, 2855,
1665, 1595, 1506, 1441, 1273, 1250, 1221, 1123, 1003, 805, 690,
593 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d (ppm) 8.03e7.94 (m, 2H),
7.56e7.64 (m, 1H), 7.49 (t, J¼7.8 Hz, 2H), 4.25 (t, J¼5.4 Hz, 2H), 3.54
(t, J¼5.6 Hz, 2H), 1.88e1.70 (m, 4H), 1.62 (s, 2H); 13C NMR (100 MHz,
CDCl3) d (ppm) 194.3,187.9,134.1,133.3,129.7,128.8, 53.0, 48.1, 26.4,
25.3, 24.0; HRMS (ESI): m/z [MþH]þ calcd for C13H16NOS: 234.0947;
found: 234.0948.
4.3.3. 2-(4-Methylpiperazin-1-yl)-1-phenyl-2-thioxoethanone
(4c). Yield 81%; yellow solid; mp 95e98 ꢀC; IR (KBr): 2984, 2940,
2853, 2799, 2744, 1671, 1591, 1511, 1444, 1292, 1255, 1222, 1163,
Scheme 4. The proposed mechanism for the present reaction.
This three-component reaction conveniently achieved the forma-
tion of C]S and CeN bonds through several mechanistically dif-
ferent reactions (iodination, nucleophilic substitution, and
Kornblum Oxidation). Further applications of this I2-promoted sp3
CeH functionalization strategy will be reported in due course.
1139, 1031, 994, 949, 697 cmꢁ1; 1H NMR (400 MHz, CDCl3)
d (ppm)
8.00e7.94 (m, 2H), 7.64e7.57 (m, 1H), 7.49 (t, J¼7.8 Hz, 2H), 4.32
(t, J¼4.8 Hz, 2H), 3.59 (t, J¼5.0 Hz, 2H), 2.63 (t, J¼5.2 Hz, 2H), 2.43
(t, J¼4.8 Hz, 2H), 2.34 (s, 3H); 13C NMR (100 MHz, CDCl3)
d (ppm)
194.9, 187.6, 134.1, 132.9, 129.5, 128.7, 54.3, 53.7, 51.1, 46.4, 45.3;
HRMS (APCI): m/z [MþH]þ calcd for C13H17N2OS: 249.1056; found:
249.1055.
4. Experimental
4.1. General
4.3.4. 2-(4-Ethylpiperazin-1-yl)-1-phenyl-2-thioxoethanone
(4d). Yield 78%; yellow solid; mp 73e76 ꢀC; IR (KBr): 2965, 2928,
2870, 2810, 2772, 1667, 1596, 1515, 1446, 1292, 1264, 1238, 1017,
All substrates and reagents were commercially available and
used without further purification. TLC analysis was performed us-
ing pre-coated glass plates. Column chromatography was per-
formed using silica gel (200e300 mesh). IR spectra were recorded
on a PerkineElmer PE-983 infrared spectrometer as KBr pellets
with absorption in cmꢁ1. 1H spectra were recorded in CDCl3 on 400/
703, 686 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d (ppm) 8.01e7.94
(m, 2H), 7.65e7.57 (m, 1H), 7.49 (t, J¼7.8 Hz, 2H), 4.33 (t, J¼4.6 Hz,
2H), 3.60 (t, J¼5.0 Hz, 2H), 2.67 (t, J¼5.2 Hz, 2H), 2.53e2.41 (m, 4H),
1.10 (t, J¼7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d (ppm) 194.8,
187.8, 134.2, 133.0, 129.6, 128.7, 52.2, 51.6(3), 51.6(1), 51.3, 46.6, 11.8;
HRMS (APCI): m/z [MþH]þ calcd for C14H19N2OS: 263.1212; found:
263.1211.
600 MHz NMR spectrometers and resonances (d) are given in parts
per million relative to tetramethylsilane. Data are reported as fol-
lows: chemical shift, multiplicity (s¼singlet, d¼doublet, t¼triplet,
m¼multiplet), coupling constants (Hertz), and integration. 13C
spectra were recorded in CDCl3 on 100 MHz NMR spectrometers
4.3.5. N-Cyclohexyl-2-oxo-2-phenylethanethioamide
85%; yellow solid; mp 128e132 ꢀC; IR (KBr): 3290, 2939, 2853,1661,
1595, 1548, 1447, 1413, 1271, 1240, 1064, 886, 694 cmꢁ1 1H NMR
(600 MHz, CDCl3)
(4e). Yield
and resonances (d) are given in ppm. HRMS were obtained on an
;
apex-Ultra MS spectrometer. MS was recorded using EI (70 eV).
Melting points were determined using an electrothermal capillary
melting point apparatus and not corrected. The X-ray crystal-
structure determinations were obtained on a Bruker SMART APEX
CCD system.
d
(ppm) 8.39 (s, 1H), 7.96 (d, J¼7.8 Hz, 2H), 7.55
(t, J¼7.2 Hz, 1H), 7.40 (t, J¼7.8 Hz, 2H), 4.50e4.40 (m, 1H), 2.15
(d, J¼10.8 Hz, 2H), 1.80 (d, J¼13.2 Hz, 2H), 1.69 (d, J¼13.2 Hz, 1H),
1.51e1.32 (m, 4H), 1.31e1.20 (m, 1H); 13C NMR (100 MHz, CDCl3)
d
(ppm) 192.7, 188.2, 133.7, 133.4, 130.4, 128.0, 53.5, 30.9, 25.2, 24.4;
HRMS (ESI): m/z [MþH]þ calcd for C14H18NOS: 248.1104; found:
4.2. General procedure for synthesis of 4a (4a as an example)
248.1102.
A mixture of acetophenone 1a (120 mg, 1.0 mmol), morpholine
2a (87 mg, 1.0 mmol), NaSH$nH2O 3a (278 mg, 2.0 mmol), and io-
dine (381 mg, 1.5 mmol) in DMSO (3 mL) was stirred at 120 ꢀC for
5 h. After disappearance of the reactant (monitored by TLC), and
added 50 mL water to the mixture, then extracted with EtOAc three
times (3ꢂ50 mL). The extract was washed with 10% Na2S2O3
solution (w/w), dried over anhydrous Na2SO4, and evaporation. The
residue was purified by column chromatography on silica gel
(petroleum ether/EtOAc¼8:1) to yield the desired product 4a as
a yellow solid (202.2 mg, 86% yield).
4.3.6. 2-Morpholino-2-thioxo-1-(p-tolyl)ethanone (4f). Yield 85%;
yellow solid; mp 115e117 ꢀC; IR (KBr): 2958, 2921, 2854, 1659, 1601,
1506,1438,1271,1232,1114,1032, 948, 735cmꢁ1; 1H NMR (600 MHz,
CDCl3)
(t, J¼4.8 Hz, 2H), 3.90 (t, J¼4.8 Hz, 2H), 3.68 (d, J¼4.2 Hz, 2H), 3.59
(s, 2H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3)
(ppm) 195.8,187.8,
d
(ppm) 7.88 (d, J¼8.4 Hz, 2H), 7.29 (d, J¼8.4 Hz, 2H), 4.32
d
145.6,130.6,129.8,129.6, 66.4, 66.3, 51.8, 47.0, 21.8; HRMS (ESI): m/z
[MþH]þ calcd for C13H16NO2S: 250.0896; found: 250.0897.
4.3.7. 1-(4-Methoxyphenyl)-2-morpholino-2-thioxoethanone
(4g).14b Yield 81%; yellow solid; mp 120e123 ꢀC; IR (KBr): 3066,
2977, 2937, 2848, 1652, 1594, 1511, 1441, 1324, 1264, 1165, 1103,
4.3. Characterization data
1025, 938, 853, 685, 609 cmꢁ1; 1H NMR (400 MHz, CDCl3)
d (ppm)
4.3.1. 2-Morpholino-1-phenyl-2-thioxoethanone (4a).14b Yield 86%;
yellow solid; mp 113e116 ꢀC; IR (KBr): 2973, 2856, 1657, 1595, 1505,
7.96 (d, J¼8.8 Hz, 2H), 6.96 (d, J¼8.8 Hz, 2H), 4.32 (t, J¼4.8 Hz, 2H),
3.98e3.80 (m, 5H), 3.68 (s, 2H), 3.60 (s, 2H); 13C NMR (100 MHz,
1445, 1285, 1265, 1104, 950, 702 cmꢁ1
;
1H NMR (600 MHz, CDCl3)
CDCl3) d (ppm) 195.9, 187.1, 164.5, 132.2, 125.8, 114.2, 66.4, 66.3,

H.-Z. Li et al. / Tetrahedron 70 (2014) 4645e4651
4649
55.6, 51.8, 47.0; MS (EI): m/z 266.05 (Mþ1, 3.04), 265.02 (M, 19.61),
2852, 1643, 1623, 1509, 1272, 1223, 1111, 1028, 931, 755 cmꢁ1
NMR (600 MHz, CDCl3)
;
1H
180.05 (1.40), 135.02 (100.00), 107.04 (5.86).
d
(ppm) 8.51 (s, 1H), 8.03 (d, J¼8.4 Hz, 1H),
7.95 (d, J¼8.4 Hz, 1H), 7.92 (d, J¼8.4 Hz, 1H), 7.88 (d, J¼8.4 Hz, 1H),
7.66e7.60 (m, 1H), 7.59e7.53 (m, 1H), 4.42e4.42 (m, 2H), 3.93
(t, J¼4.8 Hz, 2H), 3.68 (d, J¼3.6 Hz, 2H), 3.63 (s, 2H); 13C NMR
4.3.8. 1-(3-Methoxyphenyl)-2-morpholino-2-thioxoethanone
(4h).14b Yield 87%; yellow solid; mp 86e89 ꢀC; IR (KBr): 2973, 2924,
2862, 1659, 1601, 1583, 1509, 1438, 1292, 1268, 1113, 1026, 968, 875,
(100 MHz, CDCl3)
d (ppm) 195.7, 188.0, 136.1, 132.4, 132.3, 130.5,
731, 526 cmꢁ1
;
1H NMR (600 MHz, CDCl3)
d
(ppm) 7.58e7.49
129.7, 129.3, 128.9, 127.8, 127.1, 124.2, 66.5, 66.3, 51.9, 47.2; HRMS
(ESI): m/z [MþH]þ calcd for C16H16NO2S: 286.0896; found:
286.0898.
(m, 2H), 7.39 (t, J¼7.8 Hz, 1H), 7.16 (d, J¼7.8 Hz, 1H), 4.36e4.28
(m, 2H), 3.93e3.87 (m, 2H), 3.85 (s, 3H), 3.68 (d, J¼4.2 Hz, 2H), 3.59
(s, 2H); 13C NMR (100 MHz, CDCl3)
d (ppm) 195.2,187.5,159.8,134.3,
129.8,122.5,120.9,113.2, 66.2, 66.1, 55.3, 51.7, 46.9; HRMS (ESI): m/z
4.3.15. 2-Morpholino-1-(naphthalen-1-yl)-2-thioxoethanone
(4o). Yield 85%; brown solid; mp 121e124 ꢀC; IR (KBr): 2978, 2918,
2859, 1651, 1501, 1439, 1270, 1227, 1112, 1024, 931, 781, 500 cmꢁ1; 1H
[MþH]þ calcd for C13H16NO3S: 266.0845; found: 266.0846.
4.3.9. 1-(4-Ethoxyphenyl)-2-morpholino-2-thioxoethanone
(4i). Yield 87%; yellow solid; mp 131e134 ꢀC; IR (KBr): 2976, 2901,
2856, 1649, 1600, 1571, 1504, 1261, 1236, 1170, 1114, 1034, 951, 854,
NMR (600 MHz, CDCl3)
d
(ppm) 9.20 (d, J¼8.4 Hz, 1H), 8.06
(d, J¼8.4 Hz, 1H), 8.01 (d, J¼6.6 Hz, 1H), 7.88 (d, J¼7.8 Hz, 1H),
7.70e7.64 (m, 1H), 7.57 (t, J¼7.2 Hz, 1H), 7.49 (t, J¼7.8 Hz, 1H), 4.35
(t, J¼4.8 Hz, 2H), 3.91 (t, J¼4.8 Hz, 2H), 3.69 (d, J¼4.8 Hz, 4H); 13C NMR
749, 661, 526 cmꢁ1 1H NMR (600 MHz, CDCl3)
; d (ppm) 7.94
(d, J¼8.4 Hz, 2H), 6.94 (d, J¼9.0 Hz, 2H), 4.32 (t, J¼4.8 Hz, 2H),
(100 MHz, CDCl3) d (ppm) 196.6,189.3,135.5,134.0,132.9,131.3,129.1,
4.14e4.08 (m, 2H), 3.89 (t, J¼4.8 Hz, 2H), 3.68 (s, 2H), 3.59 (s, 2H),
129.0,128.6,126.9,125.9,124.2, 66.4, 66.3, 51.9, 47.3; HRMS (ESI): m/z
1.44 (t, J¼7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d (ppm) 196.1,187.2,
164.0,132.2,125.6,114.6, 66.4, 66.3, 63.9, 51.8, 47.0,14.5; HRMS (ESI):
[MþH]þ calcd for C16H16NO2S: 286.0896; found: 286.0898.
m/z [MþH]þ calcd for C14H18NO3S: 280.1002; found: 280.1000.
4.3.16. 1-(Furan-2-yl)-2-morpholino-2-thioxoethanone (4p). Yield
93%; yellow solid; mp 97e100 ꢀC; IR (KBr): 2974, 2854, 1640, 1503,
4.3.10. 1-(4-Fluorophenyl)-2-morpholino-2-thioxoethanone
(4j). Yield 75%; yellow solid; mp 130e135 ꢀC; IR (KBr): 2979, 2916,
2856, 1658, 1594, 1502, 1277, 1236, 1112, 1029, 951, 849, 744, 659,
1460, 1394, 1274, 1241, 1108, 1028, 962, 775, 528 cmꢁ1 1H NMR
;
(400 MHz, CDCl3)
d
(ppm) 7.71 (s, 1H), 7.34 (d, J¼3.2 Hz, 1H), 6.62
(t, J¼1.6 Hz, 1H), 4.27 (t, J¼4.4 Hz, 2H), 3.87 (t, J¼4.6 Hz, 2H), 3.71
606 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d (ppm) 8.08e7.98 (m, 2H),
(d, J¼4.8 Hz, 2H), 3.66 (d, J¼4.8 Hz, 2H); 13C NMR (100 MHz, CDCl3)
7.17 (t, J¼8.6 Hz, 2H), 4.33 (t, J¼5.0 Hz, 2H), 3.91 (t, J¼5.0 Hz, 2H),
d (ppm) 193.1, 175.6, 149.3, 148.2, 121.5, 112.7, 66.1, 65.8, 51.6, 47.1;
3.71 (t, J¼4.8 Hz, 2H), 3.60 (t, J¼4.8 Hz, 2H); 13C NMR (100 MHz,
HRMS (ESI): m/z [MþH]þ calcd for C10H12NO3S: 226.0532; found:
CDCl3)
d
(ppm) 195.1, 186.3, 167.6, 165.1, 132.6, 132.5, 130.0, 116.3,
226.0533.
116.1, 66.4, 66.3, 51.9, 47.1; HRMS (ESI): m/z [MþH]þ calcd for
C
12H13FNO2S: 254.0646; found: 254.0650.
4.3.17. 2-Morpholino-1-(thiophen-2-yl)-2-thioxoethanone
(4q). Yield 90%; yellow solid; mp 166e167 ꢀC; IR (KBr): 2986, 2860,
1634, 1502, 1440, 1406, 1269, 1237, 1107, 1027, 925, 779, 744, 721,
4.3.11. 1-(4-Chlorophenyl)-2-morpholino-2-thioxoethanone
(4k).14b Yield 76%; yellow solid; mp 137e139 ꢀC; IR (KBr): 2966,
2921, 2854, 1660, 1584, 1500, 1266, 1234, 1112, 1029, 949, 738,
523 cmꢁ1; 1H NMR (600 MHz, CDCl3)
d
(ppm) 7.80 (s,1H), 7.77 (s,1H),
7.17 (d, J¼4.2 Hz, 1H), 4.30 (d, J¼3.6 Hz, 2H), 3.89 (d, J¼4.2 Hz, 2H),
3.71 (s, 2H), 3.66 (s, 2H); 13C NMR (100 MHz, CDCl3)
(ppm) 194.2,
523 cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
(ppm) 7.94 (d, J¼8.4 Hz, 2H),
d
7.47 (d, J¼8.4 Hz, 2H), 4.32 (t, J¼4.8 Hz, 2H), 3.91 (t, J¼4.8 Hz, 2H),
181.0,140.2,136.2,135.6,128.6, 66.5, 66.3, 52.0, 47.2; HRMS (ESI): m/
z [MþH]þ calcd for C10H12NO2S2: 242.0304; found: 242.0305.
3.71 (t, J¼4.8 Hz, 2H), 3.60 (t, J¼4.4 Hz, 2H); 13C NMR (100 MHz,
CDCl3) d (ppm) 194.8, 186.4, 141.0, 131.6, 131.1, 129.3, 66.5, 66.3, 51.9,
47.1; MS (EI): m/z 270.21 (Mþ1, 1.82), 269.03 (M, 34.52), 211.04
4.3.18. 1-(Benzofuran-2-yl)-2-morpholino-2-thioxoethanone
(4r). Yield 95%; yellow solid; mp 152e155 ꢀC; IR (KBr): 3009, 2961,
2857, 1646, 1548, 1503, 1298, 1271, 1163, 1111, 1029, 976, 748,
(13.43),183.98 (5.26),139.06 (38.43),130.06 (100.00),111.07 (30.19).
4.3.12. 2-Morpholino-1-(4-nitrophenyl)-2-thioxoethanone
(4l). Yield 61%; yellow solid; mp 177e181 ꢀC; IR (KBr): 2976, 2925,
2855, 2361, 1663, 1600, 1519, 1441, 1346, 1267, 1231, 1107, 1029, 951,
527 cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
(ppm) 7.70 (d, J¼7.6 Hz, 1H),
7.66 (d, J¼1.6 Hz, 1H), 7.57 (d, J¼8.4 Hz, 1H), 7.49 (t, J¼7.8 Hz, 1H),
7.31 (t, J¼7.2 Hz, 1H), 4.30 (t, J¼4.2 Hz, 2H), 3.89 (t, J¼4.0 Hz, 2H),
809, 710 cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
(ppm) 8.32 (d, J¼8.8 Hz,
3.70 (d, J¼5.6 Hz, 4H); 13C NMR (100 MHz, CDCl3)
d (ppm) 192.7,
2H), 8.17 (d, J¼8.8 Hz, 2H), 4.34 (t, J¼4.8 Hz, 2H), 3.93 (t, J¼5.0 Hz,
177.0, 155.9, 149.3, 128.9, 126.4, 124.0, 123.3, 117.3, 112.1, 66.1, 65.8,
51.7, 47.1; HRMS (ESI): m/z [MþH]þ calcd for C14H14NO3S:
276.0689; found: 276.0690.
2H), 3.75 (t, J¼4.8 Hz, 2H), 3.64 (t, J¼4.8 Hz, 2H); 13C NMR
(100 MHz, CDCl3)
d (ppm) 193.5, 184.4, 150.6, 138.2, 130.7, 123.9,
66.4, 66.3, 52.0, 47.2; HRMS (ESI): m/z [MþH]þ calcd for
C
12H13N2O4S: 281.0591; found: 281.0589.
4.3.19. 2-(2-Morpholino-2-thioxoacetyl)-9H-fluoren-9-one
(4s). Yield 73%; yellow solid; mp 197e200 ꢀC; IR (KBr): 2915, 2855,
2361, 2338, 1717, 1660, 1612, 1511, 1433, 1263, 1236, 1180, 1112, 1029,
4.3.13. 1-([1,10-Biphenyl]-4-yl)-2-morpholino-2-thioxoethanone
(4m). Yield 89%; yellow solid; mp 169e172 ꢀC; IR (KBr): 2968,
977, 739, 662, 529 cmꢁ1 1H NMR (600 MHz, CDCl3)
; d (ppm) 8.17
2852, 1657, 1598, 1511, 1441, 1263, 1104, 1007, 944, 739, 693 cmꢁ1
;
(d, J¼7.8 Hz,1H), 8.12 (s,1H), 7.66 (d, J¼7.8 Hz,1H), 7.62e7.51 (m, 3H),
7.38 (t, J¼7.2 Hz, 1H), 4.35 (t, J¼4.8 Hz, 2H), 3.93 (t, J¼4.8 Hz, 2H),
3.76e3.71 (m, 2H), 3.65 (d, J¼4.2 Hz, 2H); 13C NMR (100 MHz, CDCl3)
1H NMR (600 MHz, CDCl3)
d
(ppm) 8.06 (d, J¼8.4 Hz, 2H), 7.70
(d, J¼7.8 Hz, 2H), 7.61 (d, J¼7.8 Hz, 2H), 7.51e7.44 (m, 2H), 7.42
(t, J¼7.2 Hz, 1H), 4.37e4.31 (m, 2H), 3.94e3.88 (m, 2H), 3.71
d
(ppm) 194.4, 191.8, 185.8, 149.2, 142.5, 136.3, 135.0, 134.4, 134.1,
(d, J¼4.2 Hz, 2H), 3.63 (s, 2H); 13C NMR (100 MHz, CDCl3)
d
(ppm)
133.9, 130.5, 125.0, 124.4, 121.4, 120.6, 66.4, 66.2, 51.9, 47.1; HRMS
195.6, 187.5, 147.1, 139.4, 131.9, 130.4, 129.0, 128.5, 127.5, 127.3, 66.5,
66.3, 51.9, 47.1; HRMS (ESI): m/z [MþH]þ calcd for C18H18NO2S:
312.1053; found: 312.1053.
(ESI): m/z [MþH]þ calcd for C19H16NO3S: 338.0845; found: 338.0857.
4.3.20. 2-Oxo-N,2-diphenylethanethioamide (6a). Yield 80%; yellow
solid; mp 87e91 ꢀC; IR (KBr): 3258, 1651, 1594, 1531, 1391, 1266,
4.3.14. 2-Morpholino-1-(naphthalen-2-yl)-2-thioxoethanone
(4n). Yield 94%; yellow solid; mp 150e154 ꢀC; IR (KBr): 2963, 2920,
943, 764, 699 cmꢁ1
;
1H NMR (600 MHz, CDCl3)
d
(ppm) 10.19
(s, 1H), 8.06e8.01 (m, 2H), 8.01e7.97 (m, 2H), 7.60e7.55 (m, 1H),

4650
H.-Z. Li et al. / Tetrahedron 70 (2014) 4645e4651
7.49e7.40 (m, 4H), 7.35e7.30 (m, 1H); 13C NMR (100 MHz, CDCl3)
1600, 1488, 1395, 1265, 1179, 1101, 939, 759, 691, 509 cmꢁ1; 1H NMR
(400 MHz, CDCl3)
(ppm) 10.39 (s, 1H), 7.87 (d, J¼8.0 Hz, 2H), 7.74
d
(ppm) 190.7, 187.4, 137.6, 133.8, 133.2, 130.6, 128.9, 128.0, 127.1,
d
122.1; HRMS (ESI): m/z [MþH]þ calcd for C14H12NOS: 242.0634;
(d, J¼8.4 Hz, 2H), 7.29 (t, J¼7.8 Hz, 2H), 7.17 (t, J¼7.4 Hz, 1H), 7.03
found: 242.0634.
(d, J¼8.0 Hz, 2H), 2.25 (s, 3H); 13C NMR (100 MHz, CDCl3)
d (ppm)
191.4, 187.5, 145.1, 137.7, 130.8, 130.5, 128.8, 127.0, 123.7, 122.1, 21.7;
HRMS (APCI): m/z [MþH]þ calcd for C15H14NOS: 256.0791; found:
256.0789.
4.3.21. N-(4-Fluorophenyl)-2-oxo-2-phenylethanethioamide
(6b). Yield 75%; yellow solid; mp 120e124 ꢀC; IR (KBr): 3267, 3151,
3072, 1656, 1549, 1507, 1388, 1265, 1227, 1106, 926, 835, 691,
513 cmꢁ1
;
1H NMR (400 MHz, CDCl3)
d
(ppm) 10.37 (s, 1H),
4.3.28. 2-((4-Methoxyphenyl)amino)-1-phenylethanone
termediate A). Yield 93%; yellow solid; 1H NMR (400 MHz, CDCl3)
(ppm) 8.02 (d, J¼7.2 Hz, 2H), 7.62 (t, J¼7.4 Hz,1H), 7.51 (t, J¼7.6 Hz,
2H), 6.83 (d, J¼8.8 Hz, 2H), 6.68 (d, J¼8.8 Hz, 2H), 4.92 (s, 1H), 4.59
(s, 2H), 3.76 (s, 3H); 13C NMR (100 MHz, CDCl3)
(ppm) 195.4,152.2,
(in-
8.05e7.90 (m, 4H), 7.63e7.51 (m, 1H), 7.39 (t, J¼7.8 Hz, 2H), 7.11
(t, J¼8.6 Hz, 2H); 13C NMR (100 MHz, CDCl3)
d
(ppm) 190.4, 187.5,
d
161.9, 159.4, 134.0, 133.8, 133.4, 130.8, 128.1, 124.3, 124.2, 116.0,
115.8; HRMS (ESI): m/z [MþH]þ calcd for C14H11FNOS: 260.0540;
found: 260.0539.
d
141.4, 134.9, 133.8, 128.8, 127.7, 114.9, 114.2, 55.7, 51.2.
4.3.22. N-(4-Chlorophenyl)-2-oxo-2-phenylethanethioamide
(6c). Yield 80%; yellow solid; mp 124e125 ꢀC; IR (KBr): 3314, 1636,
1544, 1488, 1390, 1265, 1093, 833, 713, 686, 664, 512 cmꢁ1; 1H NMR
4.3.29. (E)-2-((4-Methoxyphenyl)imino)-1-phenylethanone
(in-
termediate B).17b Yield 95%; brown solid; 1H NMR (400 MHz, CDCl3)
d
(ppm) 8.35 (s,1H), 8.29 (d, J¼7.6 Hz, 2H), 7.60 (t, J¼7.4 Hz,1H), 7.49
(t, J¼7.6 Hz, 2H), 7.40 (d, J¼8.8 Hz, 2H), 6.96 (d, J¼8.8 Hz, 2H), 3.84
(s, 3H); 13C NMR (100 MHz, CDCl3)
(ppm) 190.8,160.4,154.0,141.5,
(600 MHz, CDCl3)
d
(ppm) 10.32 (s, 1H), 7.98 (d, J¼7.8 Hz, 2H), 7.95
(d, J¼9.0 Hz, 2H), 7.60e7.54 (m, 1H), 7.43e7.37 (m, 4H); 13C NMR
d
(100 MHz, CDCl3)
d
(ppm) 189.7, 187.0, 136.3, 133.9, 133.5, 132.3,
135.4, 133.3, 130.5, 128.3, 123.5, 114.5, 55.4.
130.9, 129.2, 128.1, 123.3; HRMS (ESI): m/z [MþNa]þ calcd for
C
14H10ClNNaOS: 298.0064; found: 298.0066.
Acknowledgements
4.3.23. N-(4-Bromophenyl)-2-oxo-2-phenylethanethioamide
(6d). Yield 81%; yellow solid; mp 126e129 ꢀC; IR (KBr): 3314, 1636,
1591, 1543, 1485, 1387, 1265, 1072, 1005, 830, 813, 709, 685, 663,
We thank the National Natural Science Foundation of China
(Grant Nos. 21032001 and 21272085). We also thank Dr. Xianggao
Meng for his help with X-ray diffraction analysis and Dr. Chuanqi
Zhou, Hebei University, for analytical support.
510 cmꢁ1
;
1H NMR (600 MHz, CDCl3)
d
(ppm) 10.27 (s, 1H), 7.99
(d, J¼6.6 Hz, 2H), 7.90 (d, J¼6.0 Hz, 2H), 7.61e7.48 (m, 3H),
7.45e7.35 (m, 2H); 13C NMR (100 MHz, CDCl3)
(ppm) 190.0, 187.1,
d
Supplementary data
136.8, 133.9, 133.5, 132.1, 130.8, 128.1, 123.6, 120.1; MS (EI): m/z
318.98 (M, 9.10), 215.95 (12.23), 155.00 (6.15), 135.07 (9.20), 105.01
(100.00). Anal. Calcd for C14H10BrNOS: C, 52.51; H, 3.15; N, 4.37; S,
10.01. Found: C, 52.74; H, 3.39; N, 4.33; S, 10.23.
The general experimental methods and the characterizing data
including 1H NMR, 13C NMR for products are available. Supple-
mentary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2014.05.045.
4.3.24. 2-Oxo-2-phenyl-N-(p-tolyl)ethanethioamide (6e). Yield 83%;
yellow solid; mp 98e101 ꢀC; IR (KBr): 3301, 3206, 3135, 1639, 1591,
1545, 1507, 1396, 1266, 1103, 942, 817, 692, 660, 511 cmꢁ1; 1H NMR
References and notes
(600 MHz, CDCl3)
7.86e7.80 (m, 2H), 7.55e7.49 (m, 1H), 7.39e7.34 (m, 2H), 7.23e7.18
(m, 2H), 2.34 (s, 3H); 13C NMR (100 MHz, CDCl3)
(ppm) 189.9,
d (ppm) 10.32 (s, 1H), 7.99e7.95 (m, 2H),
1. (a) Doyle, M. P.; Goldberg, K. I. Acc. Chem. Res. 2012, 45, 777; (b) Godula, K.;
Sames, D. Science 2006, 312, 67e72.
2. (a) Shilov, A. E.; Shul’pin, G. B. Chem. Rev. 1997, 97, 2879e2932; (b) Jia, C.; Ki-
tamura, T.; Fujiwara, Y. Acc. Chem. Res. 2001, 34, 633e639; (c) Ramirez, T. A.;
Zhao, B. G.; Shi, Y. Chem. Soc. Rev. 2012, 41, 931e942.
d
187.4, 137.3, 135.2, 133.7, 133.6, 130.7, 129.5, 128.0, 122.2, 21.1; HRMS
(ESI): m/z [MþH]þ calcd for C15H14NOS: 256.0791; found: 256.0791.
3. For selected examples, see: I2: (a) Yan, Y. Z.; Zhang, Y. H.; Feng, C. T.; Zha, Z. G.;
Wang, Z. Y. Angew. Chem., Int. Ed. 2012, 51, 8077e8081; (b) Zhang, J. T.; Zhu, D.
P.; Yu, C. M.; Wan, C. F.; Wang, Z. Y. Org. Lett. 2010, 12, 2841e2843; (c) Dhi-
neshkumar, J.; Lamani, M.; Alagiri, K.; Prabhu, K. R. Org. Lett. 2013, 15,
1092e1095; (d) Kumar, A.; Gupta, G.; Srivastava, S. Org. Lett. 2011, 13,
6366e6369; (e) Zhao, J. W.; Huang, H. W.; Wu, W. Q.; Chen, H. J.; Jiang, H. F. Org.
Lett. 2013, 15, 2604e2607; (f) Vuppalapati, S. V. N.; Lee, Y. R. Tetrahedron 2012,
68, 8286e8292 Iodides: (g) Uyanik, M.; Okamoto, H.; Yasui, T.; Ishihara, K.
Science 2010, 328, 1376e1379; (h) Shi, E.; Shao, Y.; Chen, S. L.; Hu, H. Y.; Liu, Z. J.;
Zhang, J.; Wan, X. B. Org. Lett. 2012, 14, 3384e3387; (i) Xie, J.; Jiang, H. L.; Cheng,
Y. X.; Zhu, C. J. Chem. Commun. 2012, 979e981; (j) Ma, L. J.; Wang, X. P.; Yu, W.;
Han, B. Chem. Commun. 2011, 11333e11335; (k) Kim, H. J.; Kim, J.; Cho, S. H.;
Chang, S. J. Am. Chem. Soc. 2011, 133, 16382e16385; (l) Fan, R. H.; Pu, D. M.; Wen,
F. Q.; Wu, J. J. Org. Chem. 2007, 72, 8994e8997.
4.3.25. N-(4-Methoxyphenyl)-2-oxo-2-phenylethanethioamide
(6f). Yield 87%; yellow solid; mp 106e111 ꢀC; IR (KBr): 3290, 2361,
2338, 1653, 1595, 1540, 1504, 1395, 1264, 1244, 1170, 1028, 943, 830,
700, 526 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d (ppm) 10.26 (s, 1H),
7.99 (d, J¼8.0 Hz, 2H), 7.88 (d, J¼8.8 Hz, 2H), 7.54 (t, J¼7.0 Hz, 1H),
7.39 (t, J¼7.4 Hz, 2H), 6.93 (d, J¼8.8 Hz, 2H), 3.81 (s, 3H); 13C NMR
(100 MHz, CDCl3)
d (ppm) 189.8, 187.6, 158.0, 133.7, 133.4, 130.7,
130.6, 128.0, 123.8, 113.9, 55.31; HRMS (ESI): m/z [MþH]þ calcd for
C
15H14NO2S: 272.0740; found: 272.0736.
4. (a) Wang, Q.; Wan, C. F.; Gu, Y.; Zhang, J. T.; Gao, L. F.; Wang, Z. Y. Green Chem.
2011, 13, 578e581; (b) Zhang, X. B.; Wang, L. Green Chem. 2012, 14, 2141e2145.
5. (a) Zhu, Y. P.; Lian, M.; Jia, F. C.; Liu, M. C.; Yuan, J. J.; Gao, Q. H.; Wu, A. X. Chem.
Commun. 2012, 9086e9088; (b) Zhu, Y. P.; Liu, M. C.; Jia, F. C.; Yuan, J. J.; Gao, Q.
H.; Lian, M.; Wu, A. X. Org. Lett. 2012, 14, 3392e3395; (c) Zhu, Y. P.; Liu, M. C.;
Cai, Q.; Jia, F. C.; Wu, A. X. Chem.dEur. J. 2013, 19, 10132e10137; (d) Zhu, Y. P.;
Jia, F. C.; Liu, M. C.; Wu, L. M.; Cai, Q.; Gao, Y.; Wu, A. X. Org. Lett. 2012, 14,
5378e5381; (e) Zhu, Y. P.; Fei, Z.; Liu, M. C.; Jia, F. C.; Wu, A. X. Org. Lett. 2013, 15,
378e381; (f) Zhu, Y. P.; Gao, Q. H.; Lian, M.; Yuan, J. J.; Liu, M. C.; Zhao, Q.; Yang,
Y.; Wu, A. X. Chem. Commun. 2011, 12700e12702; (g) Gao, Q. H.; Fei, Z.; Zhu, Y.
P.; Lian, M.; Jia, F. C.; Liu, M. C.; She, N. F.; Wu, A. X. Tetrahedron 2013, 69, 22e28;
(h) Gao, M.; Yang, Y.; Wu, Y. D.; Deng, C.; Cao, L. P.; Meng, X. G.; Wu, A. X. Org.
Lett. 2010, 12, 1856e1859; (i) Yin, G. D.; Zhou, B. H.; Meng, X. G.; Wu, A. X.; Pan,
Y. J. Org. Lett. 2006, 8, 2245e2248; (j) Xue, W. J.; Li, Q.; Zhu, Y. P.; Wang, J. G.;
Wu, A. X. Chem. Commun. 2012, 3485e3487; (k) Xue, W. J.; Li, H. Z.; Gao, F. F.;
Wu, A. X. Tetrahedron 2014, 70, 239e244; (l) Yang, Y.; Gao, M.; Zhang, D. X.; Wu,
L. M.; Shu, W. M.; Wu, A. X. Tetrahedron 2012, 68, 7338e7344; (m) Gao, Q. H.;
4.3.26. N-(4-Isopropylphenyl)-2-oxo-2-phenylethanethioamide
(6g). Yield 85%; yellow solid; mp 56e60 ꢀC; IR (KBr): 3208, 2958,
1664, 1593, 1529, 1398, 1264, 949, 835, 694, 549 cmꢁ1 1H NMR
;
(600 MHz, CDCl3)
d
(ppm) 10.18 (s, 1H), 8.02 (d, J¼8.4 Hz, 2H), 7.91
(d, J¼7.8 Hz, 2H), 7.56 (t, J¼7.8 Hz, 1H), 7.42 (t, J¼7.8 Hz, 2H), 7.30
(d, J¼8.4 Hz, 2H), 2.99e2.88 (m, 1H), 1.27 (d, J¼7.2 Hz, 6H); 13C NMR
(100 MHz, CDCl3)
d (ppm) 189.5, 187.3, 148.2, 135.5, 133.7, 130.8,
128.0, 127.5, 127.0, 122.1, 33.8, 23.8, 23.6; HRMS (ESI): m/z [MþH]þ
calcd for C17H18NOS: 284.1104; found: 284.1103.
4.3.27. 2-Oxo-N-phenyl-2-(p-tolyl)ethanethioamide
(6h). Yield
81%; yellow solid; mp 90e93 ꢀC; IR (KBr): 3308, 2361, 2338, 1636,

H.-Z. Li et al. / Tetrahedron 70 (2014) 4645e4651
4651
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