Synthesis and calming activity of 6H-2-amino-4-aryl-6- (4-β-D- allopyranosyloxyphenyl)-1,3-thiazine

Article abstract of DOI:10.1007/s10600-010-9559-8

E-(4-β-D-Allopyranosyloxyphenyl)-1-(4-substituted phenyl)propenone derivatives (1a-g) have been synthesized by the Claisen-Schmidt condensation of helicid with 4-substituted acetophenone using 10% NaOH aqueous solution as a catalyst. 6H-2-Amino-4-aryl-6-(4-β-D-allopyranosyloxyphenyl)-1,3-thiazine (2a-g) were synthesized by the 1,4-Michael reaction of 1a-g with thiourea. The structures of all the new products were established by ¹H NMR, IR, and MS spectroscopy. Compound 2b (200 mg.kg^-1) showed better sedative-hypnotic activity, so further modification of helicid should be worthwhile.

Full text of DOI:10.1007/s10600-010-9559-8

Chemistry of Natural Compounds, Vol. 46, No. 2, 2010
SYNTHESIS AND CALMING ACTIVITY OF 6H-2-AMINO-4-ARYL-6-
(4-ꢀ-D-ALLOPYRANOSYLOXYPHENYL)-1,3-THIAZINE
Li Fu, Ding Ye, Ying Li, and Shufan Yin*
UDC 547.869
E-(4-ꢀ-D-Allopyranosyloxyphenyl)-1-(4-substituted phenyl)propenone derivatives (1a–g) have been
synthesized by the Claisen-Schmidt condensation of helicid with 4-substituted acetophenone using 10%
NaOH aqueous solution as a catalyst. 6H-2-Amino-4-aryl-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine
(2a–g) were synthesized by the 1,4-Michael reaction of 1a–g with thiourea. The structures of all the new
1
–1
products were established by H NMR, IR, and MS spectroscopy. Compound 2b (200 mg·kg ) showed
better sedative-hypnotic activity, so further modification of helicid should be worthwhile.
Keywords: helicid, Claisen-Schmidt reaction, 1,3-thiazine, synthesis.
Helicid [4-formylphenyl-ꢀ-D-allopyranoside, C H O ] is a pure compound extracted from the fruit of Helicia
13 16
7
nilagirica Beed [1], which is distributed widely in Yunnan Province of China, and has been successfully used in the treatment
of patients with insomnia in China. Its structure and pharmacological mechanism are similar to gastrodin, but it has special
properties because it is a rare form of allopyranoside. Helicid is a safe sedative-hypnotic and anticonvulsant [2]. However, it
possesses some disadvantages, such as the large dose, required slow action, and low biologic utilization. It has been reported
that heterocyclic pharmaceutical agents containing sulfur have various biological activities [3–5]. Up to now, 1,3-thiazine has
not been introduced to structure of helicid. Therefore, in order to obtain helicid analogs with better therapeutic effect and low
side effect [6], we synthesized nine helicid derivatives through the Claisen-Schmidt condensation and 1,4-Michael reaction.
1,3-Thiazine has been successfully used in its structure modification. The structures of all the new compounds were characterized
1
–1
by H NMR, IR, and MS spectroscopy. We also performed preliminary bioassay tests. Compound 2b (200 mg·kg ) showed
better sedative-hypnotic activity.
In the present study, a series of helicid derivatives was synthesized (Scheme 1). E-(4-ꢀ-D-Allopyranosyloxyphenyl)-
1-(4-substituted phenyl) propenone derivatives (1a–g) have been synthesized by the Claisen-Schmidt condensation of helicid
with the 4-substituted acetophenone using 10% NaOH aqueous solution as a catalyst. 6H-2-Amino-4-aryl-6-(4-ꢀ-D-
allopyranosyloxyphenyl)-1,3-thiazine (2a–g) was synthesized by the 1,4-Michael reaction of 1a–g with thiourea. Thiourea
exhibited tautomerism in alkaline solution, and 1,3-thiazine was synthesized by 1,4-Michael addition reaction and intramolecular
cyclization. Some comparative experiments were carried out. Potassium hydroxide is a better catalyst than other alkalis. The
1
alkalinity of other alkalis is either too strong or too weak, which is inappropriate for this reaction. In the H NMR spectra,
compounds 2a–g, due to H , H protons of the thiazine ring, exibited a double peak at 5.25–5.40 and 5.03–5.08 ppm (J = 4.4–
5
6
5
4.8, J = 4.4–6.8).
6
To summarize, a concise and effective procedure has been successfully developed for the synthesis of helicid derivatives
containing 1,3-thiazine. The results of the present investigation should be of value in the synthesis of structural analogs.
Department of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China, fax: 86 028 85503392,
e-mail: chuandayouji217@163.com. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 146–148, March–April, 2010.
Original article submitted September 8, 2008.
0009-3130/10/4602-0169 02010 Springer Science+Business Media, Inc.
169

TABLE 1. Spontaneous Motion Results of Target Compounds Administered to Mice, min
Post-administration, x ꢁ s
Entry
Pre-administration, x ꢁ s
30 min
60 min
90 min
179.32ꢁ49.17
161.00ꢁ32.55
176.33ꢁ77.11
185.33ꢁ76.18
0.05% CMC
Diazepama
170.17 61.80
37.92 34.45**
13.33 17.88**
11.33 16.59***
ꢁ
ꢁ
ꢁ
ꢁ
187.73ꢁ76.08
165.55ꢁ51.57*
162.67ꢁ44.47
110.45ꢁ69.74
Helicid
167.50 38.03
149.17 59.79
153.50 46.15
164.45 53.35
ꢁ
ꢁ
ꢁ
ꢁ
2a
183.67 67.67
119.73 38.35*
84.33 59.53**
71.99 45.98**
ꢁ
166.45 55.68
ꢁ
171.89 69.10
ꢁ
183.17 61.69
ꢁ
ꢁ
ꢁ
ꢁ
2b
189.75 81.98
166.67 53.21
171.57 61.82
ꢁ
ꢁ
ꢁ
2c
183.50 60.75
147.60 54.39
159.67 67.45
ꢁ
ꢁ
ꢁ
2d
174.83 55.64
160.83 99.71
182.67 46.78
ꢁ
ꢁ
ꢁ
2e
2f
187.33 75.87
155.43 43.49
99.15 38.97*
119.53 54.67*
ꢁ
ꢁ
ꢁ
ꢁ
2g
172.41ꢁ68.57
158.67ꢁ43.46
165.37ꢁ58.29
171.17ꢁ59.34
______
a
*P < 0.05; **P < 0.01, ***P < 0.001 compared with 0.05% CMC. Dose, mg/kg – 200. Diazepam – 20 mg/kg.
OH
O
OH
O
NaOH
EtOH
O
CH CH
C
R
O
HO
O
CHO
CH C
3
R
HO
+
O
HO
HO
HO
HO
a - g
1a - g
R
OH
O
SH
S
5
H N
2
NH
H N
NH
2
3
2
O
N
HO
S
EtOH/KOH, reflux
HO
HO
1
NH
2
2a - g
1a, 2a: R = H; 1b, 2b: R = CH ; 1c, 2c: R = OCH ; 1d, 2d: R = Cl
3
3
1e, 2e: R = Br; 1f, 2f: R = F; 1g, 2g: R = C H
2
5
Scheme 1
EXPERIMENTAL
1
Melting points were determined on a Thomas-Hoover melting point apparatus and are uncorrected. H NMR spectra
were taken on a Bruker AV-400 MHz spectrometer with TMS as internal standard. IR spectra were recorded on a Perkin–
Elmer FT-IR spectrometer (KBr disk). Mass spectra were obtained on a Finnigan-LCQDECA mass spectrometer (ESI-LR-
MS) and a Bruker Daltoics Bio TOF-Q mass spectrometer (ESI-HR-MS). Flash column chromatography was performed on
silica gel (300–400 mesh, Qingdao, China). Thin-layer chromatography (TLC) was performed on precoated Merck silica gel
60F plates. An electronic balance (Satorius BS210S) and multi-function mouse locomotor activity recorder (YLS-1A) were
254
used. All the other reagents and solvent were commercially available and used without further purification. According to the
literature [6], compounds 1a–e were obtained.
General Procedure for the Preparation of Compounds 1f–g. To a solution of helicid (1.420 g, 5 mmoL) in anhydrous
ethanol (30 mL), 10% sodium hydroxide aqueous solution was added until helicid dissolved in the ice bath, and then
4-substituted acetophenone (5.5 mmol) was added. The progress of the reaction was monitored by TLC. The mixture was
neutralized with diluted hydrochloric acid (3 mol/L) when the reaction ended, the solvent was removed under reduced pressure,
and water (30 mL) was added. The solution was extracted three times with ethyl acetate (25 mL), and the combined organic
layers were dried over anhydrous sodium sulfate after being concentrated by evaporation in vacuo. The residue thus separated
was subjected to column chromatography. It was first eluted with dichloromethane to remove impurities and then with
chloroform–methanol (8:1) to give a pale yellow solid.
170

E-(4-ꢀ-D-Allopyranosyloxyphenyl)-1-(4-flourophenyl)-propenone (1f). This compound was prepared from
4-fluoroacetophenone. Yield: 263 mg (65%), pale yellow solid, mp 108–110ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.45–3.95 (6H, m), 5.20 (1H, d, J = 8.0, H-1), 7.73 (1H, d, J = 16.0,
6
CH=CH), 7.07–7.88 (6H, d, PhH), 7.83 (1H, d, J = 16.0, CH=CHCO), 8.23–8.26 (2H, d, PhH), 4.51–5.11 (4H, br, 4OH).
–1
IR (KBr, ꢄ , cm ): 3400, 3072, 2900, 1655, 1598, 1509, 1426, 1333, 1180, 1084, 1030, 870, 824.
max
+
+
ESI-LR-MS m/z 405.1 [M + H] , ESI-LR-MS m/z calcd for C H O F [M + H] 405.1344, found 405.1362.
21 22
7
E-(4-ꢀ-D-Allopyranosyloxyphenyl)-1-(4-ethylphenyl)-propenone (1g). This compound was prepared from
4-ethylacetophenone. Yield: 290 mg (70%), pale yellow solid, mp 85–87ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 1.12–1.16 (3H, t, CH ), 2.62 (2H, q, J = 15.2, CH ), 3.31–3.87 (6H,
6
3
2
m), 5.12 (1H, d, J = 8.0, H-1), 7.63 (1H, d, J = 16.0, CH=CH), 7.00–7.79 (6H, d, PhH), 7.75 (1H, d, J = 16.0, CH=CHCO), 8.01
(2H, d, PhH), 4.45–5.05 (4H, br, 4OH).
–1
IR (KBr, ꢄ , cm ): 3437, 2935, 2891, 1651, 1606, 1509, 1334, 1175, 1078, 1030, 978, 845, 821. ESI-LR-MS
max
+
+
m/z 437.1 [M + Na] ; ESI-LR-MS m/z calcd for C H O Na [M + Na] 437.1571, found 437.1584.
23 26
7
General Procedure for the Preparation of Compounds 2a–g. In a round bottomed flask, a mixture of 2a–g (1 mmol),
thiourea (1.2 mmol), and potassium hydroxide (110 mg) in 95ꢂ ethanol (15 mL) was introduced. The mixture was heated to
reflux, and the progress of the reaction was monitored by TLC. It was acidified with dilute hydrochloric acid (1 mol/L) to give a
yellow solid when the reaction ended, then filtered. The solution was concentrated, and the residue thus separated was subjected
to column chromatography. It was first eluted with ethyl acetate to remove impurities, then with chloroform–hexane–methanol
(3:1:1) to give a solid.
6H-2-Amino-4-phenyl-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2a). This compound was prepared from
1a. Yield: 231 mg (52%), yellow solid, mp 138–140ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.13–3.92 (6H, m), 5.07 (1H, d, J = 6.4, H-6), 5.11 (1H, d, J = 8.0,
6
H-1), 5.36 (1H, d, J = 4.8, H-5), 7.02–7.52 (9H, d, PhH), 4.47–5.06 (4H, br, 4OH), 9.07–9.82 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3368, 2925, 1608, 1559, 1508, 1232, 1178, 1080, 1035, 832, 760, 696. ESI-LR-MS m/z 467.1
max
+
+
[M + Na] ; ESI-LR-MS m/z calcd for C H O N SNa [M + Na] 467.1247, found 467.1254.
22 24
6 2
6H-2-Amino-4-(4-methylphenyl)-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2b). This compound was
prepared from 1b. Yield: 254 mg (55%), yellow solid, mp 160–162ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 2.31 (3H, s, CH ) 3.12–3.92 (6H, m), 5.04 (1H, d, J = 4.4, H-6), 5.11
6
3
(1H, d, J = 8.0, H-1), 5.31 (1H, d, J = 4.8, H-5), 7.02–7.41 (8H, d, PhH), 4.41–5.04 (4H, br, 4OH), 9.05–9.80 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3370, 2925, 1608, 1559, 1508, 1233, 1178, 1081, 1031, 812, 636. ESI-LR-MS m/z 481.1
max
+
+
[M + Na] ; ESI-LR-MS m/z calcd for C H O N SNa [M + Na] 484.1404, found 481.1421.
23 26
6 2
6H-2-Amino-4-(4-methoxyphenyl)-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2c). This compound was
prepared from 1c. Yield: 237 mg (50%), yellow solid, mp 150–152ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.37 (3H, s, OCH ) 3.33–3.91 (6H, m), 5.07 (1H, d, J = 6.8, H-6), 5.11
6
3
(1H, d, J = 8.0, H-1), 5.26 (1H, d, J = 4.8, H-5), 6.92–7.46 (8H, d, PhH), 4.48–5.04 (4H, br, 4OH), 9.04–9.73 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3381, 2924, 1608, 1567, 1510, 1510, 1464, 1235, 1178, 1081, 1035, 834, 631. ESI-LR-MS
max
+
+
m/z 497.1 [M + Na] ; ESI-LR-MS m/z calcd for C H O N SNa [M + Na] 497.1353, found 497.1357.
23 26
7 2
6H-2-Amino-4-(4-chlorophenyl)-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2d). This compound was
prepared from 1d. Yield: 296 mg (62%), yellow solid, mp 155–157ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.17–3.92 (6H, m), 5.06 (1H, d, J = 4.8, H-6), 5.11 (1H, d, J = 8.0,
6
H-1), 5.39 (1H, d, J = 4.8, H-5), 7.02–7.57 (8H, d, PhH), 3.62–5.05 (4H, br, 4OH), 9.01–9.91 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3384, 2925, 1602, 1566, 1508, 1233, 1178, 1084, 1036, 832, 630. ESI-LR-MS m/z 501.0
max
+
+
[M + Na] ; ESI-LR-MS m/z calcd for C H Cl O N SNa [M + Na] 501.0858, found 501.0836.
22 23
1 6 2
6H-2-Amino-4-(4-bromophenyl)-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2e). This compound was
prepared from 1e. Yield: 298 mg (57%), yellow solid, mp 170–172ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.33–3.92 (6H, m), 5.04 (1H, d, J = 4.8, H-6), 5.11 (1H, d, J = 8.0,
6
H-1), 5.40 (1H, d, J = 4.4, H-5), 7.02–7.68 (8H, d, PhH), 4.47–5.05 (4H, br, 4OH), 9.09–9.91 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3376, 2925, 1609, 1559, 1508, 1483, 1233, 1178, 1078, 1037, 830, 630. ESI-LR-MS m/z 545.0
max
+
+
[M + Na] ; ESI-LR-MS m/z calcd for C H BrO N SNa [M + Na] 545.0352, found 545.0353.
22 23
6 2
6H-2-Amino-4-(4-fluorophenyl)-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2f). This compound was prepared
from 1f. Yield: 245 mg (53%), yellow solid, mp 173–175ꢂC.
171

1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.32–3.92 (6H, m), 5.06 (1H, d, J = 4.8, H-6), 5.11 (1H, d, J = 8.0,
6
H-1), 5.31 (1H, d, J = 4.8, H-5), 7.01–7.34 (8H, d, PhH), 4.49–5.05 (4H, br, 4OH), 9.02–9.92 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3391, 2925, 1602, 1573, 1505, 1409, 1233, 1178, 1079, 1038, 836, 574. ESI-LR-MS m/z 485.1
max
+
+
[M + Na] ; ESI-LR-MS m/z calcd for C H FO N SNa [M + Na] 485.1153, found 485.1126.
22 23
6 2
6H-2-Amino-4-(4-ethylphenyl)-6-(4-ꢀ-D-allopyranosyloxyphenyl)-1,3-thiazine (2g). This compound was prepared
from 1g. Yield: 255 mg (54%), yellow solid, mp 154–156ꢂC.
1
H NMR (400 MHz, DMSO-d , ꢃ, ppm, J/Hz): 1.18 (3H, t, CH ), 2.61 (2H, q, J = 15.2, CH ), 3.33–3.92 (6H, m),
6
3
2
5.07 (1H, d, J = 6.8, H-6), 5.11 (1H, d, J = 8.0, H-1), 5.32 (1H, d, J = 4.8, H-5), 7.02–7.42 (8H, d, PhH), 4.47–5.05 (4H, br,
4OH), 9.05–9.75 (2H, br, NH ).
2
–1
IR (KBr, ꢄ , cm ): 3369, 2926, 1608, 1557, 1508, 1470, 1233, 1177, 1081, 1035, 835, 637. ESI-LR-MS m/z 495.1
max
+
+
[M + Na] ; ESI-LR-MS m/z calcd for C H O N SNa [M + Na] 495.1560, found 495.1564.
24 28
6 2
Mice (Kunming strain) weighing 18–22 g were obtained from West China School of Pharmacy of Sichuan University
(Chengdu China). Diazepam injects were purchased from Huayin Jinqiancheng Pharmaceutical Co. (China) Ltd. The sedative-
hypnotic activity of samples was evaluated as inhibition of spontaneous motion resulting from administration of the target
compounds to mice. All samples were dissolved in 0.05% CMC (carboxymethylcellulose) to form solutions of concentration
200 mg/kg for use later. Diazepam injects were dissolved in saline to form solutions of concentration 200 mg/kg for use later.
Sixty mice were randomized in the experiment and divided into 10 groups of 6 mice each (3 male and 3 female). The mice
were placed in a recorder for 5 min before the experiment, and the same conditions were maintained throughout the experiment.
–1
In the tests, the prepared solutions were injected into the mouse stomach with a syringe at a volume of 0.2 mL·10 g , and the
spontaneous activity was recorded after the first 5 min, then after 30, 60, and 90 min. The data were recorded in the form of
–1
the number of movements per minute. Compound 2b (200 mg·kg ) showed better activity than the parent helicid. So further
modification of helicid should be worthwhile.
ACKNOWLEDGMENT
We thank the Analytical & Testing Center of Sichuan University, P. R. China for assistance in obtaining
analytical data.
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