Synthesis of 3,4-dihydro-2H-1,4-benzo[b]thiazine derivatives via DABCO-catalyzed one-pot three-component condensation reactions

Article abstract of DOI:10.1039/c3ra00123g

A series of 3,4-dihydro-2H-1,4-benzo[b]thiazines (34 examples) were efficiently synthesized in good to excellent yields through a 1,4-diazabibicyclo[2.2.2]octane (DABCO) catalyzed one-pot, three-component reaction of 2-aminobenzenethiol, aromatic aldehydes and α-halogenated ketones in the presence of K₂CO₃. The mechanism for this process was briefly discussed with a tentative catalytic cycle proposed.

Full text of DOI:10.1039/c3ra00123g

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Synthesis of 3,4-dihydro-2H-1,4-benzo[b]thiazine
derivatives via DABCO-catalyzed one-pot three-
component condensation reactions3
Cite this: RSC Advances, 2013, 3,
4643
Jiaping Wu, Yongjia Shang,* Cuie Wang, Xinwei He, Zhenglei Yan, Manman Hu
and Fuyin Zhou
Received 9th January 2013,
Accepted 25th January 2013
A series of 3,4-dihydro-2H-1,4-benzo[b]thiazines (34 examples) were efficiently synthesized in good to
excellent yields through a 1,4-diazabibicyclo[2.2.2]octane (DABCO) catalyzed one-pot, three-component
reaction of 2-aminobenzenethiol, aromatic aldehydes and a-halogenated ketones in the presence of
K2CO3. The mechanism for this process was briefly discussed with a tentative catalytic cycle proposed.
DOI: 10.1039/c3ra00123g
www.rsc.org/advances
reactions using small, simple organic base catalysts, we wish
to report herein a convenient and efficient procedure for the
synthesis of 3,4-dihydro-2H-1,4- benzo[b]thiazines by using a
Introduction
4H-1,4-benzothiazines are
a
family of molecules having
numerous important biological and pharmacological activ-
ities.1–4 For example, 2-benzoyl-7-chloro-3-methyl-5-trifluoro-
methyl-4H-1,4-benzothiazine (Fig. 1) has been used as
antihistaminics,5 antipsychotics,6 antiemetics,7 neuroleptics,8
tranquilizers,9 sedatives,10 and as an antibacterial agent,11 it is
also a promising anticarcinogen.
DABCO-catalyzed three-component reaction of 2-aminobenze-
nethiol, aromatic aldehydes and a-halogenated ketones
(Scheme 1).
Results and discussion
Consequently, the construction of this type of structure has
received considerable research interest, leading to the devel-
opment of several synthetic approaches.12–14 Surprisingly, few
synthetic methods have been available for the construction of
3,4-dihydro-2H-1,4-benzo[b]thiazines, despite the great simi-
larity in structures between these two kinds of compounds.
Multicomponent reactions (MCRs) are highly efficient
methods for the synthesis of natural and unnatural products
due to their great advantages in atom and step economy and
environmental friendliness.15,16 Hence, the development of
new MCRs has been an interesting research topic in areas of
organic, medicinal and pharmaceutical chemistry.16b,17 Our
group has been focused on the development of efficient
multicomponent reactions for the synthesis of useful mole-
cules from simple and cheap starting materials.18
Initially, the one-pot, three-component reaction of 2-amino-
benzenethiol 1, 2,4-dichlorobenzaldehyde 2f and 2-bromo-1-
(p-tolyl)ethanone 3b was carried out with 20 mol% of DABCO
in the presence of K2CO3 for reaction condition optimization
(Table 1). A screening of reaction temperature, reaction time
and solvent revealed that performing the reaction in CH3CN at
80 uC for 8 h is optimal (Table 1, entry 4): the desired product
4fb was obtained in 78% yield after only 8h, and its structure
was confirmed by 1H, 13C NMR and X-ray crystallography
(Fig. 2).
The use of other organic bases, such as triethylamine (TEA),
DMAP (4-dimethylaminopyridine), and 3-HQD (3-hydroxyqui-
nuclidine) as catalyst, all gave inferior results (Table 1, entries
10–13). Notably, a control experiment revealed that no reaction
Recently, we have reported an efficient DMAP-catalyzed
cascade reaction for the syntheses of a series of 2-aryl-
benzofurans in excellent yields.19 As a part of our ongoing
research into the development of efficient multicomponent
Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key
Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science,
Anhui Normal University, Wuhu 241000, People’s Republic of China.
E-mail: shyj@mail.ahnu.edu.cn; Fax: +86-553-3883517; Tel: +86-553-5910129
Electronic supplementary information (ESI) available. CCDC reference
3
numbers 847690 and 847691. For ESI and crystallographic data in CIF or other
electronic format see DOI: 10.1039/c3ra00123g
Fig. 1 2-Benzoyl-7-chloro-3-methyl-5-trifluoromethyl-4H-1,4-benzothiazine.
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Scheme 1 Synthesis of 3,4-dihydro-2H-1,4-benzo[b]thiazine derivatives condi-
tions: (1) DABCO (0.2 equiv), (2) K2CO3 (1.5 equiv), (3) CH3CN (solvent), 80 uC, 8 h.
was observed in the absence of DABCO (Table 1, entry 14).
Replacing K2CO3 with an organic base (TEA) or other inorganic
bases, including K3PO4, NaOH and Na2CO3, led to decreased
yields (Table 1, entries 15–18). Moreover, decreasing or
increasing the catalyst loading of DABCO is detrimental to
the yield (Table 1, entries 19–21). Thus, the optimal reaction
conditions were found to be 20 mol% of DABCO with CH3CN
as the solvent in the presence of K2CO3 at 80 uC for 8 h,
(Table 1, entry 4).
Fig. 2 X-ray crystal structure of compound 4fb.20
With the optimal reaction conditions in hand, various
aromatic aldehydes 2 and a-halogenated ketones 3 were used
to test the scope and limitation of this one-pot, three-
component reaction. The results are summarized in Table 2.
The aromatic aldehydes bearing electron-withdrawing groups
(–Cl, –Br and –NO2) generally provided higher yields, from 80
to 88%, compared to those with electron-donating ones
[–OCH3 and –N(CH3)2] (Table 2, entries 15–28). It should be
Table 2 DABCO-catalyzed three-component reaction of the synthesis of 3,4-
dihydro-2H-1,4-benzo[b]thiazines
Table 1 Optimization of the reaction conditionsa
Entry Ar
R
Product Yield %)
1
2
3
4
5
6
7
8
9
C6H5 (2a)
2a
2a
2a
4-CH3C6H4 (2b)
2b
2b
2b
C6H5 (3a)
4-CH3C6H4 (3b)
4-CH3OC6H4 (3c) 4ac
4-ClC6H4 (3d)
3a
3b
3c
3d
4aa
4ab
74
73
70
75
73
69
65
76
77
70
65
63
71
75
80
79
78
83
85
77
76
75
85
88
79
78
71
81
68
66
64
69
67
62
4ad
4ba
4bb
4bc
4bd
4be
4ca
4cb
4cc
4cd
4ce
4da
4db
4dc
4dd
4de
4ea
4eb
4ec
4ed
4ee
4fa
4fb
4fc
4fe
4ga
4gb
4gc
4gd
4hb
4cf
Entry Catalystb
Solvent Basec
T (uC) Time (h) Yield (%)
1
2
3
4
5
6
7
8
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
TEA
CH3CN K2CO3
CH3CN K2CO3
CH3CN K2CO3
CH3CN K2CO3
CH3CN K2CO3
CH3CN K2CO3
r.t. 12
10
21
50
78
79
76
71
66
45
17
73
72
50
0
61
68
70
75
10d
50e
74f
2b
4-NO2C6H4 (3e)
40
8
5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
4-CH3OC6H4 (2c)
2c
2c
2c
3a
3b
3c
3d
3e
3a
3b
3c
3d
3e
3a
3b
3c
3d
3e
3a
3b
3c
3e
3a
3b
3c
3d
80
80
80
100
80
80
80
80
80
80
80
80
80
80
80
80
80
80
80
8
24
8
8
8
8
8
8
8
8
8
8
8
8
24
8
8
8
2c
THF
DMF
H2O
K2CO3
K2CO3
K2CO3
4-BrC6H4 (2d)
2d
2d
2d
9
10
11
12
13
14
15
16
17
18
19
20
21
CH3CN K2CO3
CH3CN K2CO3
CH3CN K2CO3
DMAP
3-HQD
2d
4-NO2C6H4 (2e)
2e
2e
2e
Quinoline CH3CN K2CO3
—
CH3CN K2CO3
CH3CN TEA
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
CH3CN K3PO4
CH3CN NaOH
CH3CN Na2CO3
CH3CN K2CO3
CH3CN K2CO3
CH3CN K2CO3
2e
2,4-Cl2C6H3 (2f)
2f
2f
2f
4-(CH3)2NC6H4 (2g)
a
2g
2g
2g
Reaction conditions: 2-aminobenzenethiol (1.0 mmol), 2,4-
dichlorobenzaldehyde (1.0 mmol), 2-bromo-1-(p-tolyl)ethanone (1.0
b
c
mmol), and solvent (15 mL). 20 mol % of catalyst was used. 1.5
d
e
2,4-(CH3O)2C6H3 (2h) 3b
2c CH3 (3f)
equiv. base was used. 5 mol % of catalyst was used. 10 mol % of
catalyst was used. 30 mol % of catalyst was used.
f
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noted that the positions of these substituents did not exhibit
an obvious effect on this three-component reaction. For
example, the use of 2,4-dimethoxyl-benzaldehyde for this
reaction also gave the expected product in 67% yield
(Table 2, entry 33). The relative configuration of the product
4ec was further determined by X-ray crystallographic analysis
(Fig. 3). Among the various halogenated aromatic ketones (3)
investigated, substrates with electron-donating substituents
(Table 2, entries 6 and 7) gave lower yields than those with
electron-withdrawing groups (Table 2, entries 8 and 9) on the
benzene ring of the R group. In comparison with those
halogenated aromatic ketones (Table 2, entries 10 and 20),
halogenated aliphatic ketones generally gave lower yields
(Table 2, entry 34).
On the basis of our experimental results and previous
studies on similar three-component reactions,22–25 a plausible
mechanism for the formation of 3,4-dihydro-2H-1,4-ben-
zo[b]thiazines was proposed as shown in Scheme 2. Initially
the reaction of 4-diazabibicyclo[2.2.2]octane (DABCO) and
halogenated ketones 3would generate an ammonium salt II,
which would then be deprotonated by potassium carbonate to
give the carbanion III. The latter might attack imines IV, that
are in situ generated from the condensation of 2-aminobenze-
nethiol 1 and aromatic aldehydes 2, to form intermediate V,
which would undergo cyclization to give the final thermo-
dynamically favored product 4 and regenerate the catalyst I.
Experimental section
General
All reactions were carried out using standard round-bottom
flasks; CH2Cl2 and CH3CN were distilled from CaH2. H NMR
1
and 13C NMR spectra were recorded at room temperature in
CDCl3 on a Bruker AXS-300 MHz instrument with TMS as the
internal standard. Coupling constants are reported in Hertz
(Hz). IR spectra were taken as KBr plates; HRMS was obtained
using ESI ionization. Melting points were measured with
micro melting point apparatus. Single crystal X-ray diffraction
data was collected on Bruker SMART APEX diffractometers
with molybdenum cathodes.
General procedure for the synthesis of 3,4-dihydro-2H-1,4-
benzo[b]thiazine derivatives
To a solution of DABCO (0.2 mmol) and K2CO3 (1.5 mmol) in
CH3CN, halogenated ketone (1 mmol), 2-aminobenzenethiol (1
mmol) and aromatic aldehyde (1 mmol) were added and the
resulting mixture was stirred in an oil bath at 80 uC for 8 h.
Upon the completion of this reaction, the mixture was cooled
to room temperature, diluted with CH2Cl2 (3 6 20 mL), and
washed with water. Organic layers were combined, dried over
Na2SO4, filtered, and evaporated under vacuum. The residue
was further purified by flash column chromatography on silica
gel (300–400 mesh) with ethyl acetate and petroleum ether (60–
90 uC) (1 : 20, v/v) as the eluting solvent to give the desired
product.
Phenyl(3-phenyl-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)methanone (4aa)
Conclusions
Yellow solid; mp: 123–124 uC; 1H NMR (300 MHz, CDCl3): d
7.84 (d, J = 7.5 Hz, 2H), 7.51 (t, J = 7.1 Hz, 1H), 7.41–7.26 (m,
7H), 7.05 (q, J = 7.5 Hz, 2H), 6.68 (t, J = 8.9 Hz, 2H), 5.10 (d, J =
4.8 Hz, 1H), 4.70 (d, J = 5.4 Hz, 1H), 4.44 (s, 1H) ppm; 13C NMR
(75 MHz, CDCl3) d 194.1, 142.3, 142.2, 135.4, 133.5, 128.7,
128.6, 128.6, 128.2, 128.1, 127.5, 127.0, 118.0, 115.0, 113.6,
57.7, 47.4 ppm; IR (KBr) n 3410, 3057, 3021, 2907, 1672, 1595,
In summary, we have developed an efficient DABCO-catalyzed
one-pot three-component reaction for the synthesis of 3,4-
dihydro-2H-1,4-benzo[b]thiazines with good to excellent yields
from easily available 2-aminobenzenethiol, aromatic alde-
hydes and halogenated ketones. Further investigation of this
reaction and the properties of the resulting compounds are
underway in our laboratory. This mild annulation strategy
might have a potential application in the synthesis of other
heterocyclic aromatic compounds useful in medicinal chem-
istry.
1495, 1447, 1319, 1281, 1254, 1069, 1005, 748, 696 cm21
;
HRMS (ESI) calcd for [C21H17NOS + H]+ 332.1109, found
332.1104.
(3-Phenyl-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-yl)(p-tolyl)
methanone (4ab)
1
Red solid; mp: 116–117 uC; H NMR (300 MHz, CDCl3): d 7.83
(d, J = 7.5 Hz, 1H), 7.54 (t, J = 7.8 Hz, 1H), 7.41 (t, J = 7.2 Hz,
2H), 7.28 (t, J = 8.0 Hz, 3H), 7.12–7.02 (m, 4H), 6.69–6.63 (m,
2H), 5.06 (d, J = 5.7, 1H), 4.69 (d, J = 6.3 Hz, 1H), 4.37 (s, 1H),
2.29 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 193.5, 144.0
141.4, 140.2, 134.1, 129.4, 128.5, 128.5, 128.4, 128.1, 127.3,
126.4, 118.3, 115.5, 113.1, 58.2, 44.9, 21.7 ppm; IR (KBr) n 3381,
3048, 3028, 2920, 1667, 1605, 1587, 1504, 1485, 1450, 1319,
1298, 1194, 1184, 1069, 1015, 964, 826, 768, 745 cm21; HRMS
(ESI) calcd for [C22H19NOS + H]+ 346.1266, found 346.1260.
(4-Methoxyphenyl)(3-phenyl-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4ac)
Yellow solid; mp: 154–155 uC; 1H NMR (300 MHz, CDCl3): d
7.85 (d, J = 7.5 Hz, 2H), 7.52 (d, J = 6.9 Hz, 1H), 7.42 (d, J = 7.2
Fig. 3 X-ray crystal structure of compound 4ec.21
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Scheme 2 Possible mechanism for the synthesis of 3,4-dihydro-2H-1,4-benzo[b]thiazines.
Hz, 2H), 7.35 (d, J = 7.8 Hz, 2H), 7.06 (q, J = 7.8 Hz, 1H), 6.84 (d,
J = 8.1 Hz, 1H), 6.68 (q, J = 7.5 Hz, 3H), 5.05 (d, J = 6.0 Hz, 1H),
4.71 (d, J = 6.0 Hz, 1H), 4.36 (s, 1H), 3.78 (s, 3H) ppm; 13C NMR
(75 MHz, CDCl3) d 192.5, 163.4, 141.4, 140.2, 131.8, 130.5,
129.6, 128.5, 128.4, 128.0, 127.3, 126.4, 118.3, 115.5, 113.8,
58.4, 55.5, 44.9 ppm; IR (KBr) n 3447, 3048, 2999, 2941, 2901,
1636, 1597, 1504, 1416, 1323, 1225, 1169, 1126, 1067, 1042,
1016, 901, 843, 760, 746, 689, 671 cm21; HRMS (ESI) calcd for
[C22H19NO2S + H]+ 362.1215, found 362.1205.
IR (KBr) n 3387, 3084, 3022, 2872, 1665, 1587, 1522, 1487, 1400,
1325, 1298, 1261, 1221, 1092, 1009, 752, 698 cm21; HRMS (ESI)
calcd for [C21H16NOSCl + H]+ 366.0719, found 366.0713.
Phenyl(3-(p-tolyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)methanone (4ba)
Yellow solid; mp 131–132 uC; 1H NMR (300 MHz, CDCl3): d
7.83 (d, J = 7.5 Hz, 2H), 7.50 (d, J = 7.2 Hz, 1H), 7.38 (t, J = 7.5
Hz, 2H), 7.29 (d, J = 8.1 Hz, 2H), 7.12–7.02 (m, 4H), 6.69–6.63
(m, 2H), 5.05 (s, 1H), 4.69 (d, J = 6.3 Hz, 1H), 4.37 (s, 1H), 2.29
(s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 194.2, 142.3, 139.1,
138.0, 135.6, 133.3, 129.3, 128.6, 127.9, 127.4, 126.8, 118.0,
115.0, 57.6, 47.7, 21.1 ppm; IR (KBr) n 3383, 3045, 3026, 2920,
1666, 1604, 1514, 1485, 1450, 1319, 1298, 1184, 1014, 964, 825,
767, 742, 700 cm21; HRMS (ESI) calcd for [C22H19NOS + H]+
346.1266, found 346.1260.
(4-Chlorophenyl)(3-phenyl-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4ad)
Yellow solid; mp 134–135 uC; 1H NMR (300 MHz, CDCl3): d
7.87 (d, J = 8.1 Hz, 1H), 7.76 (d, J = 8.4 Hz, 2H), 7.45–7.21 (m,
6H), 7.04 (d, J = 8.1 Hz, 2H), 6.66 (d, J = 7.5 Hz, 2H), 5.08 (d, J =
5.1 Hz, 1H), 4.61 (d, J = 5.7 Hz, 1H), 4.43 (s, 1H) ppm; 13C NMR
(75 MHz, CDCl3) d 192.8, 141.5, 139.9, 134.1, 133.2, 131.4,
129.1, 129.0, 128.6, 127.7, 127.2, 118.1, 115.0, 53.1, 42.9 ppm;
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p-Tolyl(3-(p-tolyl)-3,4-dihydro-2H-benzo[b][1,4] thiazin-2-
(3-(4-Methoxyphenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)methanone (4bb)
yl)(phenyl)methanon (4ca)
Yellow solid; mp: 116–117 uC; 1H NMR (300 MHz, CDCl3): d
8.16 (d, J = 7.5 Hz,1H), 7.88 (d, J = 7.8 Hz, 1H), 7.75 (d, J = 7.8
Hz, 1H), 7.61–7.41 (m, 3H), 7.32–7.18 (m, 3H), 7.06 (t, J = 7.1
Hz, 1H), 6.68 (t, J = 8.1 Hz, 1H), 5.10 (d, J = 5.7 Hz, 1H), 4.70 (d,
Yellow solid; mp: 111–112 uC; 1H NMR (300 MHz, CDCl3): d
7.85 (d, J = 7.5 Hz, 2H), 7.52 (d, J = 6.9 Hz, 1H), 7.42 (d, J = 7.2
Hz, 2H), 7.35 (d, J = 7.8 Hz, 2H), 7.06 (q, J = 7.8 Hz, 1H), 6.84 (d,
J = 8.1 Hz, 1H), 6.68 (q, J = 7.5 Hz, 3H), 5.05 (d, J = 6.0 Hz, 1H),
4.71 (d, J = 6.0 Hz, 1H), 4.36 (s, 1H), 3.78 (s, 1H) ppm; 13C NMR
(75 MHz, CDCl3) d 194.5, 159.4, 142.3, 135.6, 133.9, 133.4,
128.6, 128.6, 128.6, 127.9, 126.8, 118.0, 115.0, 114.1, 114.0,
57.4, 55.3, 47.8 ppm; IR (KBr) n 3341, 3049, 3013, 2957, 2899,
2835, 1686, 1587, 1514, 1466, 1447, 1362, 1288, 1250, 1238,
1184, 1024, 972, 837, 816, 745, 685 cm21; HRMS (ESI) calcd for
[C22H19NO2S + H]+ 362.1215, found 362.1206.
J = 6.0 Hz, 1H), 4.44 (s, 1H), 2.45 (s, 3H), 2.38 (s, 3H) ppm; 13
C
NMR (75 MHz, CDCl3) d 194.0, 144.4, 142.3, 139.2, 137.9,
129.6, 129.3, 129.3, 128.7, 128.0, 127.9, 127.4, 126.7, 118.0,
115.0, 57.6, 47.6, 21.7, 21.1 ppm; IR (KBr) n 3319, 3039, 3022,
2968, 2916, 2862, 1674, 1606, 1593, 1570, 1492, 1481, 1321,
1307, 1290, 1253, 1178, 1099, 1070, 1010, 835, 794, 736, 721
cm21; HRMS (ESI) calcd for [C23H21NOS + H]+ 360.1422, found
360.1416.
(3-(4-Methoxyphenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(p-tolyl)methanone (4cb)
(4-Methoxyphenyl)(3-(p-tolyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4bc)
Yellow solid; mp: 117–118 uC; 1H NMR (300 MHz, CDCl3): d
7.75 (d, J = 7.5 Hz, 2H), 7.33 (d, J = 8.1 Hz, 2H), 7.19 (d, J = 7.5
Hz, 2H), 7.04 (q, J = 7.5 Hz, 2H), 6.83 (d, J = 8.1 Hz, 2H), 6.66 (q,
J = 7.8 Hz, 2H), 5.02 (d, J = 5.7 Hz, 1H), 4.70 (d, J = 6 Hz, 1H),
4.41 (s, 1H), 3.75 (s, 3H), 2.38 (s, 3H) ppm; 13C NMR (75 MHz,
CDCl3) d 194.1, 159.4, 144.4, 142.4, 134.0, 133.1,129.4, 128.7,
127.8, 126.7, 118.0, 115.1, 114.3, 114.0, 57.4, 55.3, 47.7, 21.7
ppm; IR (KBr) n 3419, 3041, 3007, 2954, 2908, 2833, 1678, 1606,
1587, 1514, 1465, 1365, 1288, 1249, 1238, 1180, 1170, 1095,
1026, 972, 846, 825, 765, 744 cm21; HRMS (ESI) calcd for
[C23H21NO2S + H]+ 376.1371, found 376.1365.
Yellow solid; mp: 132–133 uC; 1H NMR (300 MHz, CDCl3): d
7.83 (d, J = 8.7 Hz, 2H), 7.30 (d, J = 7.8 Hz, 2H), 7.12–6.99 (m,
4H), 6.85 (d, J = 8.4 Hz, 2H), 6.64 (t, J = 8.9 Hz, 2H), 5.03 (d, J =
5.7 Hz, 1H), 4.68 (d, J = 6.3 Hz, 1H), 4.37(s, 1H), 3.82 (s, 3H),
2.30 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 192.9, 163.8,
142.4, 139.1, 137.9, 131.0, 129.3, 128.6, 127.8, 127.5, 126.7,
117.9, 115.1, 114.5, 113.8, 57.8, 55.5, 47.5, 21.2 ppm; IR (KBr) n
3363, 3039, 3007, 2912, 2912, 2843, 1674, 1597, 1510, 1494,
1483, 1313, 1290, 1267, 1251, 1170, 1126, 1068, 1014, 842, 800,
748 cm21; HRMS (ESI) calcd for [C23H21NO2S + H]+ 376.1371,
found 376.1366.
(4-Methoxyphenyl)(3-(4-methoxyphenyl)-3,4-dihydro-
(4-Chlorophenyl)(3-(p-tolyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4cc)
2H-benzo[b][1,4]thiazin-2-yl)methanone (4bd)
Yellow solid; mp: 115–116 uC; 1H NMR (300 MHz, CDCl3): d
7.83 (d, J = 8.4 Hz, 2H), 7.32 (d, J = 8.1 Hz, 2H), 7.08–6.98 (m,
2H), 6.83 (t, J = 9.3 Hz, 4H), 6.65 (q, J = 8.0 Hz, 2H), 5.00 (d, J =
6.6 Hz, 1H), 4.68 (d, J = 6.9 Hz, 1H), 4.34 (s, 1H), 3.82 (s, 3H),
3.74 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 193.0, 163.8,
159.4, 142.4, 133.9, 131.0, 128.7, 128.6, 127.7, 126.6, 118.0,
115.1, 114.6, 114.0, 113.8, 57.6, 55.5, 55.3, 47.6 ppm; IR (KBr) n
3390, 3068, 3034, 2999, 2958, 2927, 2835, 1672, 1600, 1571,
1512, 1475, 1465, 1421, 1288, 1265, 1249, 1238, 1219, 1180,
1166, 1095, 1028, 974, 827, 746 cm21; HRMS (ESI) calcd for
[C23H21NO3S + H]+ 392.1320, found 392.1309.
Yellow solid; mp: 108–109 uC; 1H NMR (300 MHz, CDCl3): d
8.06(d, J = 8.1 Hz, 1H), 7.90 (d, J = 7.8 Hz, 1H), 7.76 (d, J = 8.1
Hz, 2H), 7.50–7.43 (m, 2H), 7.36–7.26 (m, 4H), 7.12–7.00 (m,
3H), 6.69–6.63 (m, 3H), 5.04 (d, J = 5.7 Hz, 1H), 4.60 (d, J = 6 Hz,
1H), 4.39 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) d: 193.1,
142.2, 139.0, 138.1, 131.4, 130.0, 129.6, 129.4, 129.5, 128.9,
128.0, 127.3, 127.0, 118.0, 115.0, 57.5, 47.7, 21.1 ppm; IR (KBr)
n 3417, 3041, 3016, 2910, 2854, 1722, 1703, 1674, 1589, 1487,
1398,1319, 1288, 1215, 1130, 1091, 1006, 964, 833, 798, 758,
740, 678 cm21; HRMS (ESI) calcd for [C22H18ClNOS + H]+
380.0876, found 380.0869.
(4-Chlorophenyl)(3-(4-methoxyphenyl)-3,4-dihydro-
(4-Nitrophenyl)(3-(p-tolyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4cd)
2-yl)methanone (4be)
Red solid; mp: 90–91 uC; 1H NMR (300 MHz, CDCl3): d 7.75 (d,
J = 7.5 Hz, 2H), 7.32 (t, J = 9.6 Hz, 4H), 7.03 (q, J = 7.7 Hz, 2H),
6.82 (d, J = 7.5 Hz, 2H), 6.65 (q, J = 7.1 Hz, 2H), 5.00 (d, J = 5.7
Hz, 1H), 4.60 (d, J = 6 Hz, 1H), 4.40 (s, 1H), 3.80 (s, 3H) ppm;
13C NMR (75 MHz, CDCl3) d 193.3, 159.5, 142.3, 139.9, 133.9,
130.0, 129.6, 128.9, 128.6, 128.4, 127.9, 126.9, 118.0, 115.1,
114.0, 57.3, 55.3, 47.8 ppm; IR (KBr) n 3367, 3039, 3022, 2916,
2860, 1674, 1606, 1593, 1494, 1483, 1321, 1307, 1290, 1253,
1178, 1153, 1099, 1070, 1012, 835, 794, 736 cm21 ; HRMS (ESI)
calcd for [C22H18ClNO2S + H]+ 396.0825, found 396.0815.
1
Pink solid; mp 166–168 uC; H NMR (300 MHz, CDCl3): d 8.22
(d, J = 8.4 Hz, 2H), 7.94 (d, J = 8.7 Hz, 2H), 7.27 (t, J = 6.8 Hz,
2H), 7.14–7.01 (m, 4H), 5.09 (s, 1H), 4.58 (d, J = 5.4 Hz, 1H),
4.47 (s, 1H), 2.31 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d
192.5, 142.2, 140.2, 139.1, 138.3, 134.9, 129.9, 129.5, 129.4,
128.3, 127.4, 127.2, 123.7, 118.1, 115.1, 57.3, 48.3, 21.1 ppm; IR
(KBr) n 3398, 3018, 2920, 2858, 1681, 1602, 1589, 1519, 1483,
1348, 1325, 1261, 1217, 1099, 1010, 854, 815, 750 cm21; HRMS
(ESI) calcd for [C22H18N2O3S + H]+ 391.1116, found 391.1110.
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7.8 Hz, 2H), 5.07 (d, J = 4.7 Hz, 1H), 4.52 (d, J = 5.0 Hz, 1H),
4.45 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) d 192.4, 141.9,
141.5, 140.0, 133.5, 131.8, 130.0, 129.2, 129.0, 128.2, 127.2,
122.2, 118.3, 115.2, 113.0, 56.8, 47.2 ppm; IR (KBr) n 739, 3383,
3063, 3021, 2918, 1680, 1587, 1514, 1485, 1398, 1321, 1287,
1258, 1090, 1070, 1009, 833, 775, 738 cm21; HRMS (ESI) calcd
for [C21H15BrClNOS + H]+ 443.9825, found 443.9820.
(3-(4-Methoxyphenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(4-nitrophenyl)methanone (4ce)
Pink solid; mp: 148–149 uC; 1H NMR (300 MHz, CDCl3): d 8.21
(d, J = 8.4 Hz, 2H), 7.94 (d, J = 8.4 Hz, 2H), 7.32 (d, J = 8.7 Hz,
2H), 7.03 (d, J = 7.8 Hz, 2H), 6.84 (d, J = 8.1 Hz, 2H), 6.68 (t, J =
7.2 Hz, 2H), 5.06 (d, J = 3.6 Hz, 1H), 4.59 (d, J = 5.7 Hz, 1H),
4.43 (s, 1H), 3.76 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d
192.7, 159.6, 150.2, 142.2, 140.2, 133.9, 129.5, 128.5, 128.2,
127.3, 123.8, 118.2, 115.2, 115.1, 114.1, 57.1, 55.3, 48.4 ppm; IR
(KBr) n 3363, 3072, 3001, 2958, 2929, 2837, 1681, 1602, 1512,
1483, 1346, 1323, 1303, 1249, 1217, 1168, 1033, 854, 829, 802,
750, 696 cm21; HRMS (ESI) calcd for [C22H18N2O4S + H]+
407.1065, found 407.1059.
(3-(4-Bromophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(4-nitrophenyl)methanone (4de)
Pink solid; mp: 154–155 uC; 1H NMR (300 MHz, CDCl3): d 7.26
(d, J = 8.2 Hz, 2H), 8.00 (d, J = 8.2 Hz, 2H), 7.49 (d, J = 7.8 Hz,
2H), 7.30 (t, J = 8.2 Hz, 2H), 7.07 (t, J = 7.1 Hz, 1H), 7.02 (d, J =
7.5 Hz, 1H), 5.17 (s, 1H), 4.53 (s, 2H) ppm; 13C NMR (75 MHz,
CDCl3) d 191.7, 150.3, 141.8, 141.7, 139.8, 136.8, 131.8, 131.6,
129.5, 129.1, 128.5, 127.7, 123.8, 122.3, 118.4, 118.3, 115.2,
111.9, 58.48, 56.5 ppm; IR (KBr) n 3402, 3043, 3019, 2963, 1682,
1603, 1518, 1483, 1396, 1346, 1323, 1260, 1092, 1070, 1011,
(3-(4-bromophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(phenyl)methanone (4da)
Yellow solid; mp: 147–148 uC; 1H NMR (300 MHz, CDCl3): d
7.87 (d, J = 7.8 Hz, 2H), 7.56 (t, J = 7.2 Hz, 1H), 7.44 (q, J = 7.8
Hz, 3H), 7.30 (t, J = 7.8 Hz, 2H), 7.06 (t, J = 6.0 Hz, 2H), 6.70 (t, J
= 7.5 Hz, 2H), 5.11 (s, 1H), 4.64 (d, J = 5.4 Hz, 1H), 4.42 (s, 1H)
ppm; 13C NMR (75 MHz, CDCl3) d 194.0, 144.4, 142.4, 139.2,
137.9, 130.0, 129.6, 129.3, 129.3, 128.7, 127.9, 126.7, 118.0,
115.0, 57.6, 47.6 ppm; IR (KBr) n 3399, 3061, 3019, 2907, 1668,
860, 800, 750, 723, 702 cm21
; HRMS (ESI) calcd for
[C21H15BrN2O3S + H]+ 455.0065, found 455.0056.
(3-(4-Nitrophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(phenyl)methanone (4ea)
Yellow solid; mp: 167–168 uC; 1H NMR (300 MHz, CDCl3): d
8.18 (d, J = 8.1 Hz, 2H), 7.85 (d, J = 7.2 Hz, 2H), 7.57 (q, J = 7.5
Hz, 3H), 7.06 (q, J = 7.8 Hz, 2H), 6.71 (d, J = 7.5 Hz, 2H), 5.28 (s,
1H), 4.57 (d, J = 3.9 Hz, 1H), 4.54 (s, 1H) ppm; 13C NMR (75
MHz, CDCl3) d 192.9, 150.4, 141.4, 134.6, 133.7, 128.7, 128.6,
128.5, 128.4, 127.4, 123.8, 118.6, 115.3, 56.6, 46.2 ppm; IR
(KBr) n 3343, 3071, 2930, 2849, 1682, 1595, 1516, 1476, 1447,
1346, 1288, 1217, 1096, 1015, 972, 845, 752, 683 cm21; HRMS
(ESI) calcd for [C21H16N2O3S + H]+ 377.0960, found 377.0953.
1589, 1485, 1312, 1277, 1252, 1070, 1007, 820, 752, 700 cm21
;
HRMS (ESI) calcd for [C21H16BrNOS + H]+ 410.0214, found
410.0206.
(3-(4-Bromophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(p-tolyl)methanone (4db)
Yellow solid; mp: 140–141 uC; 1H NMR (300 MHz, CDCl3): d
7.72 (d, J = 7.8 Hz, 2H), 7.40 (d, J = 7.8 Hz, 2H), 7.27–7.16 (m,
4H), 7.01 (d, J = 6.9 Hz, 2H), 6.63 (d, J = 8.4 Hz, 2H), 5.04 (s,
1H), 4.58 (d, J = 5.1 Hz, 1H), 4.34 (s, 1H), 2.35 (s, 3H) ppm; 13C
NMR (75 MHz, CDCl3) d 193.3, 141.4, 138.1, 137.1, 133.0,
132.3, 128.9, 128.3, 127.9, 127.5, 126.9, 126.3, 125.8, 116.9,
114.0, 56.5, 46.7, 20.0 ppm; IR (KBr) n 3382, 3012, 2956, 2912,
2835, 1685, 1587, 1514, 1465, 1446, 1364, 1287, 1238, 1184,
1094, 1024, 972, 837, 816, 750, 685 cm21; HRMS (ESI) calcd for
[C21H15Cl2NOS + H]+ 424.0371, found 424.0367.
(3-(4-Nitrophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(p-tolyl)methanone (4eb)
Yellow solid; mp: 175–176 uC; 1H NMR (300 MHz, CDCl3): d
8.17 (d, J = 8.7 Hz, 2H), 7.75 (d, J = 8.1 Hz, 2H), 7.59 (d, J = 8.7
Hz, 2H), 7.20 (d, J = 7.8 Hz, 2H), 7.05 (q, J = 6.9 Hz, 2H), 6.71 (d,
J = 7.2 Hz, 2H), 5.27 (s, 1H), 4.57 (d, J = 4.2 Hz, 1H), 4.51 (s, 1H),
2.38 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 192.7, 150.2,
147.7, 144.8, 141.4, 132.3, 129.4, 128.8, 128.5, 128.3, 127.3,
123.8, 118.6, 115.3, 56.7, 46.4, 21.7 ppm; IR (KBr) n 3419, 3070,
2968, 2916, 2881, 1668, 1602, 1510, 1477, 1346, 1296, 1273,
1226, 1188, 1105, 1010, 952, 844, 763, 696 cm21; HRMS (ESI)
calcd for [C22H18N2O3S + H]+ 391.1116, found 391.1108.
(3-(4-Bromophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(4-methoxyphenyl)methanone (4dc)
Yellow solid; mp: 120–121 uC; 1H NMR (300 MHz, CDCl3): d
8.16 (d, J = 8.4 Hz, 2H), 7.84 (d, J = 8.4 Hz, 2H), 7.58 (d, J = 8.1
Hz, 2H), 7.04 (d, J = 7.5 Hz, 2H), 6.87 (d, J = 8.4 Hz, 2H), 6.69 (d,
J = 6.9 Hz, 2H), 5.25 (s, 1H), 4.57 (d, J = 4.2 Hz, 1H), 3.84 (s, 3H)
ppm; 13C NMR (75 MHz, CDCl3) d 191.7, 164.0, 150.1, 147.1,
141.4, 121.0, 128.5, 128.2, 127.2, 123.7, 118.6, 115.3, 113.9,
56.9, 55.5, 42.6 ppm; IR (KBr) n 3375, 3005, 2926, 2837, 1667,
1597, 1574, 1506, 1483, 1314, 1260, 1169, 1070, 1026, 1009,
837, 822, 743 cm21; HRMS (ESI) calcd for [C22H18BrNO2S + H]+
440.0320, found 440.0309.
(4-Methoxyphenyl)(3-(4-nitrophenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4ec)
Yellow solid; mp: 178–179 uC; 1H NMR (300 MHz, CDCl3): d
8.16 (d, J = 8.1 Hz, 2H), 7.84 (d, J = 8.7 Hz, 2H), 7.59 (d, J = 8.4
Hz, 2H), 7.04 (d, J = 7.8 Hz, 2H), 6.87 (d, J = 8.7 Hz, 2H), 6.69 (d,
J = 6.9 Hz, 2H), 5.25 (s, 1H), 4.57 (d, J = 4.2 Hz, 1H), 4.49 (s, 1H),
3.84 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 191.8, 164.0,
150.1, 147.5, 141.5, 131.1, 128.5, 128.2, 127.7, 127.2, 123.7,
118.6, 115.3, 113.9, 113.2, 56.9, 55.6, 46.5 ppm; IR (KBr) n 3332,
3064, 3010, 2937, 2883, 2841, 1653, 1598, 1570, 1514, 1477,
1425, 1350, 1292, 1269, 1209, 1184, 1099, 1020, 854, 842, 752,
678 cm21; HRMS (ESI) calcd for [C22H18N2O4S + H]+ 407.1065,
found 407.1054.
(3-(4-Bromophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(4-chlorophenyl)methanone (4dd)
1
Red solid; mp: 111–112 uC; H NMR (300 MHz, CDCl3): d 7.77
(d, J = 8.2 Hz, 2H), 7.43 (d, J = 8.0 Hz, 2H), 7.36 (d, J = 8.2 Hz,
2H), 7.27 (d, J = 8.2 Hz, 2H), 7.04 (t, J = 7.7 Hz, 2H), 6.67 (t, J =
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7.24 (d, J = 8.4 Hz, 1H), 7.06 (t, J = 7.5 Hz, 1H), 6.98 (d, J = 7.8
Hz, 1H), 6.90 (d, J = 7.8 Hz, 2H), 6.72–6.62 (m, 2H), 5.56 (d, J =
4.5 Hz, 1H), 4.68 (d, J = 5.1 Hz, 1H), 4.51 (s, 1H), 3.85 (s, 3H)
ppm; 13C NMR (75 MHz, CDCl3) d 191.6, 163.6, 141.5, 140.0,
134.0, 131.8, 131.4, 131.0, 129.0, 128.9, 127.6, 127.5, 127.1,
118.0, 115.0, 113.8, 110.8,55.5, 53.2, 42.5 ppm; IR (KBr) n 3373,
3055, 3030, 2976, 2935, 2837, 1654, 1595, 1512, 1485, 1462,
(4-Chlorophenyl)(3-(4-nitrophenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4ed)
Yellow solid; mp: 165–166 uC; 1H NMR (300 MHz, CDCl3): d
8.19 (d, J = 8.1 Hz, 2H), 7.80 (d, J = 8.4 Hz, 2H), 7.59 (d, J = 8.4
Hz, 2H), 7.39 (d, J = 8.1 Hz, 2H), 7.07 (m, 2H), 6.71 (d, J = 7.8
Hz, 2H), 5.29 (s, 1H), 4.56 (s, 1H), 4.49 (s, 1H) ppm; 13C NMR
(75 MHz, CDCl3) d 191.7, 150.3, 147.6, 141.3, 140.2, 133.0,
130.1, 129.0, 128.6, 128.4, 127.6, 123.8, 118.7, 115.3, 112.2,
56.5, 46.4 ppm; IR (KBr) n 3396, 3095, 3068, 2972, 2875, 1672,
1587, 1570, 1510, 1477, 1402, 1344, 1296, 1273, 1259, 1220,
1093, 1008, 952, 844, 788, 763, 750, 696 cm21; HRMS (ESI)
calcd for [C21H15ClN2O3S + H]+ 411.0570, found 411.0562.
1357, 1313, 1274, 1259, 1226, 1172, 1020, 846, 817, 734 cm21
;
HRMS (ESI) calcd for [C22H17Cl2NO2S + H]+ 430.0435, found
430.0426.
(3-(2,4-Dichlorophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(4-nitrophenyl)methanone (4fe)
Yellow solid; mp: 128–129 uC; 1H NMR (300 MHz, CDCl3): d
7.94 (d, J = 8.1 Hz, 2H), 7.75 (d, J = 6.9 Hz, 1H), 7.54–7.18 (m,
5H), 7.08 (t, J = 7.4 Hz, 1H), 6.99–6.89 (m, 2H), 5.58 (d, J = 3.3
Hz, 1H), 4.64 (d, J = 4.8 Hz, 1H), 4.51 (s, 1H) ppm; 13C NMR (75
MHz, CDCl3) d 191.7, 153.8, 141.4, 139.8, 132.4, 131.4, 131.4,
130.7, 129.7, 128.9, 127.6, 127.5, 127.2, 125.8, 118.6, 118.1,
115.0, 53.2, 42.8 ppm; IR (KBr) n 3402, 3057, 2924, 2854, 1730,
1674, 1585, 1544, 1483, 1471, 1309, 1259, 1211, 1168, 1099,
1047, 898, 862, 817, 765, 742 cm21; HRMS (ESI) calcd for
[C21H14Cl2N2O3S + H]+ 445.0180, found 445.0181.
(4-Nitrophenyl)(3-(4-nitrophenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4ee)
Red solid; mp: 174–175 uC; 1H NMR (300 MHz, CDCl3): d 8.27–
8.20 (m, 4H), 8,0(d, J = 7.8 Hz, 2H), 7.61 (d, J = 7.5 Hz, 2H), 7.10
(d, J = 6.9 Hz, 1H), 6.98 (d, J = 7.2 Hz, 1H), 6.73 (t, J = 8.1 Hz,
2H), 5.38 (s, 1H), 4.64 (s, 1H), 4,46 (s, 1H) ppm; 13C NMR (75
MHz, CDCl3) d 190.9, 150.4, 147.7, 141.3, 139.4, 137.2, 129.6,
128.9, 128.3, 128.1, 123.9, 123.8, 118.7, 115.4, 56.1, 46.7 ppm;
IR (KBr) n 3366, 3105, 3075, 2968, 2872, 1682, 1601, 1526, 1508,
1477, 1342, 1298, 1260, 1215, 1103, 1009, 856, 768, 727 cm21
;
HRMS (ESI) calcd for [C21H15N3O5S + H]+ 422.0811, found
422.0802.
(3-(4-(Dimethylamino)phenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)(phenyl)methanone (4ga)
Yellow solid; mp: 147–148 uC; 1H NMR (300 MHz, CDCl3): d
7.84 (d, J = 7.2 Hz, 2H), 7.49 (d, J = 6.6 Hz, 1H), 7.38 (t, J = 7.1
Hz, 2H), 7.26 (d, J = 7.2 Hz, 2H), 7.09–6.99 (m, 2H), 6.65 (t, J =
8.6 Hz, 4H), 4.97 (d, J = 6 Hz, 1H), 4.73 (d, J = 5.1 Hz, 1H), 4.33
(s, 1H), 2.90 (s, 6H) ppm; 13C NMR (75 MHz, CDCl3) d 194.8,
150.5, 142.6, 135.8, 133.3, 129.2, 128.6, 128.6, 128.3, 127.8,
126.7, 117.8, 115.0, 114.4, 112.5, 57.6, 48.0, 40.5 ppm; IR (KBr)
n 3332, 3051, 2883, 2854, 2800, 1678, 1612, 1595, 1521, 1498,
1481, 1444, 1352, 1325, 1286, 1253, 1213, 1165, 1128, 1004,
945, 817, 738, 692 cm21; HRMS (ESI) calcd for [C23H22N2OS +
H]+ 375.1531, found 375.1525.
(3-(2,4-Dichlorophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(phenyl)methanone (4fa)
Yellow solid; mp: 149–150 uC; 1H NMR (300 MHz, CDCl3): d
7.87 (d, J = 7.5 Hz, 2H), 7.54 (d, J = 7.5 Hz, 1H), 7.44(q, J = 11,3
Hz, 4H), 7.24 (d, J = 6.9 Hz, 1H), 7.08 (t, J = 7.2 Hz, 1H), 6.97 (d,
J = 7.8 Hz, 1H), 6.73–6.63 (m, 2H), 5.59 (d, J = 5.1 Hz, 1H), 4.65
(d, J = 5.1 Hz, 1H), 4.54 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3)
d 192.7, 141.5, 139.9, 134.8, 134.0, 133.3, 131.7, 131.4, 129.0,
128.7, 128.6, 127.7, 127.2, 118.1, 115.0, 110.4, 53.0, 42.7 ppm;
IR (KBr) n 3421, 3084, 3053, 3026, 2993, 1668, 1593, 1521, 1490,
1463, 1446, 1354, 1340, 1301, 1220, 1130, 1095, 1047, 1014,
867, 806, 732, 707 cm21; HRMS (ESI) calcd for [C21H15Cl2NOS
+ H]+ 400.0330, found 400.0320.
(3-(4-(Dimethylamino)phenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)(p-tolyl)methanone (4gb)
Yellow solid; mp: 146–147 uC; 1H NMR (300 MHz, CDCl3): d
7.75 (d, J = 6.6 Hz, 2H), 7.26 (d, J = 6.3 Hz, 2H), 7.18 (d, J = 6.9
Hz, 2H), 7.08–6.98 (m, 2H), 6.63 (d, J = 7.5 Hz, 4H), 4.96 (d, J =
5.7 Hz, 1H), 4.71 (d, J = 5.4 Hz, 1H), 4.30 (s, 1H), 2.89 (s, 6H),
2.36 (s, 3H) ppm ; 13C NMR (75 MHz, CDCl3) d 194.3, 150.4,
144.3, 142.7, 133.3, 129.3, 129.2, 128.9, 128.7, 128.3, 127.7,
126.6, 117.8, 115.0, 112.5, 57.6, 47.9, 40.5, 21.7 ppm; IR (KBr) n
3412, 2953, 2880, 2801, 1672, 1601, 1524, 1477, 1360, 1315,
1300, 1261, 1229, 1184, 1161, 1096, 818, 799, 748 cm21; HRMS
(ESI) calcd for [C24H24N2OS + H]+ 389.1687, found 389.1681.
(3-(2,4-Dichlorophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(p-tolyl)methanone (4fb)
Yellow solid; mp: 129–130 uC; 1H NMR (300 MHz, CDCl3): d
7.79 (d, J = 7.5 Hz, 2H), 7.47 (d, J = 8.1 Hz, 1H), 7,38 (s, 1H),
7.23 (d, J = 6.6 Hz, 3H), 7.06 (d, J = 7.2 Hz, 1H), 6.97 (d, J = 7.4
Hz, 1H), 6.73–6.63 (m, 2H), 5.57 (s, 1H), 4.67 (d, J = 5.4 Hz, 1H),
4.53 (s, 1H), 2.40 (s, 3H) ppm; 13C NMR (75 MHz, CDCl3) d
192.5, 144.2, 141.5, 140.0, 134.0, 132.3, 131.7, 131.4, 129.4,
129.0, 128.9, 128.7, 127.6, 127.1, 118.1, 115.0, 110.7, 53.104,
42.7, 21.7 ppm; IR (KBr) n 3265, 3051, 3026, 2922, 1662, 1604,
1595, 1523, 1492, 1463, 1338, 1301, 1263, 1226, 1182, 1130,
1095, 1047, 1014, 869, 821, 788, 731 cm21; HRMS (ESI) calcd
for [C22H17Cl2NOS + H]+ 414.0486, found 414.0479.
(3-(4-(Dimethylamino)phenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)(4-methoxyphenyl)methanone
(4gc)
Yellow solid; mp: 166–168 uC; 1H NMR (300 MHz, CDCl3): d
7.84 (d, J = 8.1 Hz, 2H), 7.26 (d, J = 7.8 Hz, 2H), 7.09–6.97 (m,
2H), 6.84 (d, J = 8.1 Hz, 2H), 6.63 (q, J = 9.9 Hz, 4H), 4.95 (d, J =
6.9 Hz, 1H), 4.71 (d, J = 6.6 Hz, 1H), 4.30 (s, 1H), 3.82 (s, 3H),
2.89 (s, 6H) ppm; 13C NMR (75 MHz, CDCl3) d 193.2, 163.7,
(3-(2,4-Dichlorophenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-
yl)(4-methoxyphenyl)methanone (4fc)
Yellow solid; mp: 146–147 uC; 1H NMR (300 MHz, CDCl3): d
7.87 (d, J = 8.4 Hz, 2H), 7.46 (d, J = 8.4 Hz, 1H), 7.37 (s, 1H),
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150.4, 142.7, 131.0, 129.1, 128.8, 128.3, 127.6, 126.5, 117.8,
1145.0, 114.9, 113.7, 112.4, 57.8, 55.5, 47.7, 40.5 ppm; IR (KBr)
n 3358, 3032, 3005, 2868, 2802, 1670, 1597, 1568, 1525, 1508,
1475, 1419, 1359, 1311, 1296, 1261, 1163, 1097, 1024, 983, 850,
815, 746 cm21; HRMS (ESI) calcd for [C24H24N2O2S + H]+
405.1636, found 405.1630.
References
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(4-Chlorophenyl)(3-(4-(dimethylamino)phenyl)-3,4-dihydro-
2H-benzo[b][1,4]thiazin-2-yl)methanone (4gd)
Yellow solid; mp: 163–165 uC; 1H NMR (300 MHz, CDCl3): d
7.75 (d, J = 6.9 Hz, 2H), 7.33 (d, J = 8.7 Hz, 2H), 7.23 (d, J = 8.1
Hz, 2H), 7.03 (q, J = 7.8 Hz, 2H), 6.71–6.61 (m, 4H), 4.94 (d, J =
6.0 Hz, 1H), 4.64 (d, J = 6.3 Hz, 1H), 4.34 (s, 1H), 2.89 (s, 6H)
ppm; 13C NMR (75 MHz, CDCl3) d 190.4, 150.5, 142.6, 139.7,
134.3, 132.0, 123.0, 128.8, 128.2, 127.8, 126.8, 117.9, 115.0,
112.4, 111.0, 57.7, 48.1, 40.5 ppm; IR (KBr) n 3332, 3055, 3010,
2889, 2810, 1681, 1612, 1587, 1527, 1475, 1444, 1398, 1365,
1313, 1288, 1166, 1085, 1008, 977, 844, 808, 788, 746 cm21
;
HRMS (ESI) calcd for [C23H21ClN2OS + H]+ 409.1141, found
409.1136.
(3-(2,4-Dimethoxyphenyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-
2-yl)(p-tolyl)methanone (4hb)
Yellow solid; mp: 125–126 uC; 1H NMR (300 MHz, CDCl3): d
7.73 (d, J = 7.5 Hz, 2H), 7.17 (d, J = 7.8 Hz, 2H), 7.08–6.93 (m,
4H), 6.77 (d, J = 7.8 Hz, 1H), 6.66 (t, J = 9.3 Hz, 2H), 5.00 (d, J = 6
Hz, 1H), 4.71 (d, J = 6 Hz,1H), 4.35 (s, 1H), 3.82 (s, 6H), 2.36 (s,
3H) ppm; 13C NMR (75 MHz, CDCl3) d 194.1, 149.0, 148.8,
144.4, 142.4, 134.2, 133.2, 129.3, 128.7, 128.0, 127.8, 126.7,
119.8, 118.1, 115.1, 111.1, 110.5, 58.1, 56.0, 55.9, 48.0, 21.7
ppm; IR (KBr) n 3404, 3051, 3019, 3001, 2922, 2832, 1670, 1597,
1514, 1487, 1456, 1412, 1325, 1294, 1267, 1252, 1190, 1134,
1022, 833, 806, 764, 746; HRMS (ESI) calcd for [C24H23NO3S +
H]+ 406.1477, found 406.1470.
¨
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J. Ramon and M. Yus, Angew. Chem., Int. Ed., 2005, 44,
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yl)ethanone (4cf)
´
1602–1634; (c) H. Bienayme, C. Hulme, G. Oddon and
P. Schmitt, Chem.–Eur. J., 2000, 6, 3321–3329; (d)
Yellow liquid; 1H NMR (300 MHz, CDCl3): d 7.25 (d, J = 7.8 Hz,
2H), 7.08 (d, J = 7.2 Hz, 1H), 7.00 (t, J = 7,2 Hz, 1H), 6.87 (d, J =
8.4 Hz, 2H), 6.67 (t, J = 7.4 Hz, 1H), 6.58 (d, J = 7.8 Hz, 1H), 4.94
(s, 1H), 4.36 (s, 1H), 3.79 (s, 3H), 3.73 (d, J = 4.5 Hz, 1H), 2.14 (s,
3H) ppm; 13C NMR (75 MHz, CDCl3) d 203.9, 159.4, 141.8,
134.4, 128.2, 128.0, 126.8, 118.0, 115.0, 114.0, 56.2, 55.3, 53.8,
28.7 ppm; IR (KBr) n 3387, 3061, 2999, 2930, 2835, 1707, 1609,
¨
A. Domling and I. Ugi, Angew. Chem., Int. Ed., 2000, 39,
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1593, 1510, 1483, 1354, 1304, 1250, 1175, 1030, 827, 745 cm21
;
HRMS (ESI) calcd for [C17H17NO2S + H]+ 300.1058, found
300.1052.
19 Y. J. Shang, C. E. Wang, X. W. He, K. Ju, M. Zhang, S. Y. Yu
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Acknowledgements
¯
20 Crystallographic data for 4fb: space group P1, a =
This work was partially supported by the National Natural
Science Foundation of China (no. 21172001) and the Program
for the NCET (NCET-10-0004) for their financial support.
10.1879(10) Å, b = 10.7179(10) Å, c = 11.0530(11) Å, a =
95.3630(10)u, b = 109.8910(10)u, c = 115.9520(10)u, V =
977.64(16) Å3, T = 293(2)K, Z = 2. Crystallographic data for
compound 4fb (CCDC-847691) is available .
3
21 Crystallographic data for 4ec: space group Pbca, a =
10.427(2) Å, b = 19.086(4) Å, c = 19.748(4) Å, a = 90u, b =
90u, c = 90u, V = 3929.9(14) Å3, T = 293(2)K, Z = 8.
4650 | RSC Adv., 2013, 3, 4643–4651
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Crystallographic data for compound 4ec (CCDC-847690) is
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available .
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