The synthesis and biological activities of 6-aryl-3-(D-glucoheptonic- hexitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines

Article abstract of DOI:10.3184/030823407X210901

A series of novel 6-aryl-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4- triazolo[3,4-b][1,3,4] thiadiazines (2a-2j) have been synthesised in high yield by means of the reaction of 4-amino-5-mercapto-3-(D-glucoheptonic-hexitol-1-yl)- 1,2,4-triazole (1) with substituted ω-brom- oacetophenones. The structures of the compounds were determined by elemental analysis, IR, ¹H NMR, ¹³C NMR and MS. Most possessed high plant growth-regulating activities.

Full text of DOI:10.3184/030823407X210901

244 RESEARCH PAPER
APRIL, 244–246
JOURNAL OF CHEMICAL RESEARCH 2007
The synthesis and biological activities of 6-aryl-3-(D-glucoheptonic-
hexitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines
Xiaoxia Yea,b,c,d, Zhenfei Chenc, Anjiang Zhangc and Lixue Zhang*c
aChengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 P. R. China
bGraduate School of Chinese Academy of Sciences, Beijing 100049, P. R. China
cCollege of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325027, P.R.China
dDepartment of Chemistry, Wenzhou Medical College, Wenzhou 325035, P. R. China
A series of novel 6-aryl-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4] thiadiazines (2a–2j) have
been synthesised in high yield by means of the reaction of 4-amino-5-mercapto-3-(D-glucoheptonic-hexitol-1-yl)-
1,2,4-triazole (1) with substituted w-brom- oacetophenones. The structures of the compounds were determined by
elemental analysis, IR, 1H NMR, 13C NMR and MS. Most possessed high plant growth-regulating activities.
Keywords: glucoheptonic acid residue, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazines, 1,2,4-triazolo-5-thione, D-glucoheptonic-
hexitol-1-yl, synthesis
3,6-Disubstituted-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines
are important because of their antimicrobial, antibacterial,
antifungal, anti-inflammatory, diuretic, anthelmintic, analgesic
and antiparasitic biological activity.1,2 In our previous paper,
we have reported the synthesis of some compounds containing
the thiadiazine ring, which possessed moderate regulating
effects on the growth of mung bean sprouts.1 Recently,
progress has been made3-7 into combining the 1,2,4-triazole
nucleus with N-bridged heterocycles.3–7
Nonetheless, almost all of the substituents at the 3- and
6-positions in these compounds which are currently available
are alkyl or aryl groups. It is unsatisfactory to use these
compounds as medicament due to their poor water-solubility.
Hence attaching the D-hexitol-1-yl group to 7H-1,2,4-triazolo
[3,4-b][1,3,4]thiadiazines at the 3-position could improve
their absorption in biological systems. It was our objective to
prepare the title compounds.
We note that, in spite of R- being either an electron-
withdrawing group or an electron-donating group, the desired
products were obtained in very good yields, so the generality
of the reaction is excellent.
The newly synthesised compounds, 2a–2j, were tested for
their solubility in water. As we expected, the data showed
that the water-solubility of the title compounds was greater
than that of our previously prepared 3, 6-disubstituted-
7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines (see Table 1).
The title compounds have been investigated for their
biological activities in regulating the growth of wheat and
radish with reference of sterilised distilled water. After the
growth regulating percentage has been calculated using
solution of 10μg/ml and 100μg/ml of the title compounds
2a–2j for 5 days, the biological activity data is presented in
Table 2.The results indicated that among the tested compounds,
almost all the newly prepared compounds showed
a
moderate to good inhibiting effect on the growth of the stalk
and the radicel of the wheat and radish at a concentration
of 10μg/ml and 100μg/ml. However, it is interesting that
2b, 2h and 2g show promoting effect on the growth of the
stalk and the radicel of the radish at lower concentration,
10μg/ml. Hence the structure: activity relationships are worth
studying further.
All the products have been characterised by elemental
analysis, IR, 1H NMR, 13C NMR and MS. The DEPT spectra
of 2a–j all clearly show two secondary carbon atoms existing
in each synthesised compound. The signals at δ 63.4, δ 22.8–
25.9 were attributes to OCH2, SCH2 residues respectively. The
synthetic route of the title compounds is shown in Scheme 1.
H
OH
H
OH
S
C
O
H
H
H
OH H
N
NH
O
HOH2C
C
C
pyridine
H2NHN
NHNH2
+
HOH2C
HOH2C
S
reflux, 4h
N
OH OH OH H OH
NH2
HO
OH
1
H
H H OH H
N
N
ethanol
reflux, 4h
R
C
O
CH2 Br
+
S
N
OH OH OH H OH
N
R
2a-j
R: 2a: C6H5-
2b: p-ClC6H4-
2d: p-BrC6H4-
2f: 2,4-2FC6H3-
2h: p-CH3C6H4-
2j: p-C6H5C6H4-
2c: 2,4-2ClC6H3-
2e: p-FC6H4-
2g: p-O2NC6H4-
2i: p-CH3OC6H4-
Scheme 1
* Correspondent. E-mail: zhanglixuelz@yahoo.com.cn
PAPER: 07/4561

JOURNAL OF CHEMICAL RESEARCH 2007 245
Table 1 The water-solubility of the title compounds
Compounds
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
Solubility in H2O at 20°C(mg/100 ml)
12.0
13.3
2.0
12.5
15.4
12.5
20.0
2.2
20.0
2.0
131.9, 129.1, 127.6, 74.3, 74.0, 71.8, 67.4, 64.7, 63.4, 23.0. MS-ESI
(m/z): 397(M+ + 1), 379, 363, 333, 295, 279, 247, 217. Elemental
anal. calcd. for C16H20N4O6S: C, 48.5; H, 5.1; N, 14.1. Found: C,
48.6; H, 5.1; N, 14.4%.
Experimental
Carbon, hydrogen and nitrogen analyses were determined on a Flash-
1112 series elemental analyser. Rotations were measured on a Rudolph
AuTo Pol IV automatic polarimeter. IR spectra were recorded on a
Nicolet 670FT-IR using the smart OMNI-Sampler in the range 4000–
400 cm-1. 1H NMR and 13C NMR spectra were recorded on a Bruker
Avance-300 NMR spectrometer in DMSO-d6 solution using TMS as
an internal reference. MS spectra were recorded on an Agilent 1100
LC/MS. Melting points were determined on an XT-4 melting point
apparatus and were uncorrected. All chemicals and solvents used
were of AR grade.
6-(4-Chlorophenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine (2b): White powder, yield% 89%.
M.p. 223–225°C (from ethanol). [α]D = –18.1°(c 0.110, CH3OH).
IR(cm-1): 3492 (OH), 2910 (CH2), 1592 (C=N), 1470 (N=C–S), 690
(C–S–C). 1H NMR(DMSO-d6, 300 MHz, ppm): 8.05–7.65(m, 4H,
Ar–H), 5.02–4.35 (m, 6H, O–H), 4.33 (s, 2H, SCH2), 4.28–3.24(m,
7H, –OCH). 13C NMR (DMSO-d6, 75 MHz, ppm): 154.8, 153.2,
140.1, 136.8, 132.7, 129.4, 129.2, 74.2, 73.8, 71.8, 67.5, 64.8, 63.4,
22.9. MS-ESI (m/z, relative intensity, %): 433 (M+ + 2) (35), 432 (M+
+ 1) (18), 431(M+) (100), 413, 279, 251, 237, 204. Elemental anal.
calcd. for C16H19ClN4O6S: C, 44.6; H, 4.4; N, 13.0. Found: C, 44.8;
H, 4.5; N, 13.2%.
6-(2,4-Dichlorophenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-
1,2,4-triazolo[3,4-b][1,3,4]thiadiazine(2c): White powder, yield%
90%. M.p. 213–215°C (from ethanol). [α]D = –4.536°(c 0.088,
CH3OH). IR (cm-1): 3421 (OH), 2950 (CH2), 1589 (C=N), 1470
(N=C–S), 695 (C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm): 7.88–
7.63 (m, 3H, Ar–H), 4.94–4.27 (m, 6H, O–H), 4.26 (s, 2H, SCH2),
4.17–3.38 (m, 7H, –OCH). 13C NMR (DMSO-d6, 75 MHz, ppm):
154.9, 154.3, 140.2, 136.3, 133.7, 132.7, 132.5, 129.9, 128.2, 74.2,
74.1, 71.7, 67.2, 64.6, 63.4, 25.9. MS-ESI (m/z, relative intensity, %):
467 (M+ + 2) (67), 466 (M+ + 1) (19), 465 (M+) (100), 431, 285,
279, 204, 181. Elemental anal. calcd. for C16H18Cl2N4O6S: C, 41.3;
H, 3.9; N, 12.0. Found: C, 41.2; H, 3.85; N, 12.2%.
6-(4-Bromophenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine (2d): Pale yellow powder, yield%
87%. M.p. 225–227°C (from ethanol). [α]D = –11.1°(c 0.108,
CH3OH). IR (cm-1): 3490 (OH), 2950 (CH2), 1587 (C=N), 1469
(N=C–S), 690 (C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm):
7.98–7.79 (m, 4H, Ar–H), 5.02–4.98 (m, 1H, O–H), 4.54–4.30 (m,
5H, O–H), 4.36 (s, 2H, SCH2), 4.24–3.39 (m, 7H, –OCH). 13C NMR
(DMSO-d6, 75 MHz, ppm): 154.8, 153.4, 140.1, 133.0, 132.2, 129.6,
125.7, 74.2, 73.8, 71.8, 67.5, 64.8, 63.4, 22.8. MS-ESI (m/z, relative
intensity, %): 477 (M+ + 2) (100), 476 (M+ + 1) (19), 475 (M+)
(100), 459, 325, 297, 279, 237, 204. Elemental anal. calcd. (%) for
C16H19BrN4O6S: C, 40.4; H, 4.0; N, 11.8. Found: C, 40.3; H, 4.1; N,
12.0%.
Synthesis of 4-Amino-3-(D-glucoheptonic-hexitol-1-yl)-1H-1, 2,
4-triazole-5-thione (1): general procedure
To a solution of α-D-glucoheptonic-γ-lactone (4.16 g, 20 mmol)
dissolved in pyridine was added thiocarbohydrazide (2.12 g,
20 mmol), which have been prepared by literature methods.8
The mixture was refluxed for 4 h with stirring. After concentration
under reduced pressure, the crude product was recrystallised from
alcohol to afford compound (1): White powder, yield% 80%.
M.p. 153–155°C (from ethanol). [α]D = +34.5°(c 0.104, CH3OH).
IR(cm-1): 3470 (OH), 2925 (CH2), 1620 (C=N), 1502 (N=C–S).
1H NMR (DMSO-d6, 300 MHz, ppm): 13.54 (s, 1H, N–H), 5.46
(s, 2H, -NH2), 4.05–3.99 (m, 6H, O–H), 3.42–3.38 (m, 7H, –OCH).
13C NMR (DMSO-d6, 75 MHz, ppm): 165.3, 152.8, 74.1, 74.1, 71.7,
67.2, 65.0, 63.4. MS-ESI (m/z): 297(M+ + 1), 279, 278, 241, 205,
181, 159. Elemental anal. calcd. (%) for C8H16N4O6S: C, 32.4; H,
5.4; N, 18.9. Found(%): C, 32.3; H, 5.5; N, 18.7.
Synthesisof6-aryl-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-triazolo
[3,4-b][1,3,4]thiadiazines (2): general procedure
A mixture of 4-amino-3-(D-glucoheptonic-hexitol-1-yl)-1H-1, 2,
4-triazole-5-thione (1.7 mmol) and ω-bromoacetophenones (1.7
mmol) in ethanol (20 ml) was stirred under reflux for 4 h. The solid
obtained on cooling was filtered, washed with cold water, air dried
and recrystallised from ethanol to give the pure products (2a–2j).
6-Phenyl-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-triazolo[3,4-
b][1,3,4]thiadiazine (2a): White powder, yield% 91%. M.p. 196–
198°C (from ethanol). [α]D = –8.3°(c 0.096, CH3OH). IR (cm-1): 3494
1
(OH), 2920 (CH2), 1590 (C=N), 1466 (N=C–S), 700 (C–S–C). H
NMR (DMSO-d6, 300 MHz, ppm): 8.04–7.59 (m, 5H, Ar–H), 5.04–
4.22 (m, 6H, O–H), 4.35 (s, 2H, SCH2), 4.07–3.96 (m, 7H, –OCH).
13C NMR (DMSO-d6, 75 MHz, ppm): 154.8, 154.3, 140.2, 133.8,
6-(4-Fluorophenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine(2e): White powder, yield% 86%.
M.p. 203–205°C (from ethanol). [α]D = –14.0°(c 0.114, CH3OH).
Table 2 Effect of compounds 2a–2j on the plant growth-regulating of wheat and radisha
Compounds
Concentrations (μg/ml)
Radish
Wheat
Stalk
Radicel
Stalk
Radicel
2a
2b
2c
2d
2e
2f
100
10
100
10
100
10
100
10
100
10
100
10
100
10
100
10
****
****
******
++++++
******
**
******
**
++
***
****
****
*
++++
******
+++
***
****
******
+++++
******
*****
******
**
*****
*****
***
******
*****
******
******
******
**
***
****
**
****
***
****
*****
***
*
**
**
*
****
***
*****
****
+++
+++
+
+++
***
****
****
**
+++
***
+
***
****
+
**
***
***
2g
2h
2i
++++
******
++++
****
****
**
100
10
100
10
****
*****
**
****
****
*****
2j
**
***
Inhibition rate: * <10%; ** 10–30%; *** 30–50%; **** 50–70%; ***** 70–90%; ****** >90%.
Promotion rate. + <10%; ++ 10–30%; +++ 30–50%; ++++ 50–70%; +++++ 70–90%; ++++++ >90%.
PAPER: 07/4561

246 JOURNAL OF CHEMICAL RESEARCH 2007
IR (cm-1): 3490 (OH), 2956 (CH2), 1597 (C=N), 1463 (N=C–S),
698 (C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm): 8.12–7.40 (m,
4H, Ar–H), 5.03–4.30 (m, 6H, O–H), 4.37 (s, 2H, SCH2), 4.24–3.41
(m, 7H, –OCH). 13C NMR (DMSO-d6, 75 MHz, ppm): 166.0, 162.7,
154.8, 153.3, 140.1, 130.3, 130.2, 116.4, 116.1, 74.2, 73.9, 71.8, 67.5,
64.8, 63.4, 23.0. MS-ESI (m/z): 415 (M+ + 1), 397, 379, 341, 326,
301. Elemental anal. calcd. for C16H19FN4O6S: C, 46.4; H, 4.6; N,
13.5. Found: C, 46.3; H, 4.6; N, 13.2%.
6-(2, 4-Difluorophenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,
4-triazolo[3,4-b] [1,3,4]thiadiazine(2f): White powder, yield% 89%.
M.p. 189–190°C (from ethanol). [α]D = –11.7°(c 0.102, CH3OH). IR
(cm-1): 3464 (OH), 2910 (CH2), 1613 (C=N), 1470 (N=C–S), 690
(C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm): 7.91–7.32 (m, 3H,
Ar–H), 4.48–4.16 (m, 6H, O–H), 4.37 (s, 2H, SCH2), 4.03–3.26 (m,
7H, –OCH). 13C NMR (DMSO-d6, 75 MHz, ppm): 165.9, 162.7,
162.5, 154.9, 151.3, 140.1, 132.1, 132.0, 119.8, 119.7, 112.9, 112.6,
105.7, 105.4, 105.0, 74.3, 74.0, 71.7, 67.3, 64.7, 63.4, 25.1. MS-ESI
(m/z): 433 (M+ + 1), 341, 283, 281, 279, 254, 253, 156. Elemental
anal. calcd. for C16H18F2N4O6S: C, 44.4; H, 4.2; N, 13.0. Found: C,
44.3; H, 4.3; N, 12.7%.
6-(4-Nitrophenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine (2g): Pale yellow powder, yield%
91%. M.p. 230–232°C (from ethanol). [α]D = –46.7°(c 0.108,
CH3OH). IR (cm-1): 3313(OH), 2984 (CH2), 1528 (C=N), 1471
(N=C–S), 677 (C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm):
8.43–8.22 (m, 4H, Ar–H), 5.07–4.22 (m, 6H, O–H), 4.46 (s, 2H,
SCH2), 4.05–3.24 (m, 9H, –OCH). 13C NMR (DMSO-d6, 75 MHz,
ppm): 155.0, 152.6, 149.2, 140.1, 139.8, 129.0, 124.2, 74.1, 73.8,
71.9, 67.5, 64.9, 63.4, 23.1. MS-ESI (m/z): 442 (M+ + 1), 413, 412,
411, 262, 232. Elemental anal. calcd. for C16H19N5O8S: C, 43.5; H,
4.3; N, 15.9. Found: C, 43.4; H, 4.3; N, 15.6%.
6-(4-Diphenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine (2j): Pale yellow powder, yield%
89%. M.p. 205–207°C (from ethanol). [α]D = –12.5°(c 0.096,
CH3OH). IR (cm-1): 3270 (OH), 2915 (CH2), 1635 (C=N), 1472
(N=C–S), 698 (C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm):
8.13–8.11 (m, 2H, Ar–H), 7.91–7.89 (m, 2H, Ar–H), 7.80–7.78
(m, 2H, Ar–H), 7.55–7.52 (m, 2H, Ar–H), 7.50–7.41 (m, 1H, Ar–H),
5.06 (s, 1H, O–H), 4.52–4.28(m, 5H, O–H), 4.42 (s, 2H, SCH2),
4.25–3.42 (m, 7H, –OCH). 13C NMR (DMSO-d6, 75 MHz, ppm):
154.8, 153.9, 143.3, 140.2, 139.0, 132.7, 129.2, 128.4, 128.3, 127.3,
127.0, 74.3, 74.0, 71.8, 67.4, 64.8, 63.4, 23.0. MS-ESI (m/z): 473(M+
+ 1), 472(M+), 455, 427, 397, 321, 293, 279. Elemental anal. calcd.
for C22H24N4O6S: C, 55.9; H, 5.1; N, 11.9. Found: C, 55.8; H, 5.2;
N, 11.65%.
Biological evaluation
Effect of compounds 2a–2j on the vegetative growth of wheat and
radish plant: Seeds were rinsed with sterilised distilled water four
times. All subsequent manipulations were carried out under a
horizontal laminar flow. Twenty seeds of each species were chosen
and individually placed in culture dishes of 9 cm diameter containing
two pieces of filter paper and 5 ml solution of the tested compounds
2a–2j (10μg/ml and 100μg/ml, respectively), and were incubated in
a growth chamber at 25°C, with a 16 h/8 h photoperiod. The set of
controls with sterilised distilled water were prepared simultaneously.
Plant length were recorded on the 5th day both for the treated
plants and for the set controls. Experiments were run in duplicate.
The equations of the growth regulating percentage (the stalk and the
radicel of the wheat and radish) are: [the average of sample length
(cm) – the average of the controls (cm)]/the average of the controls
(cm) × 100%.
6-(4-Methylphenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine (2h): White powder, yield% 87%.
M.p. 230–231°C (from ethanol). [α]D = –12.7°(c 0.094, CH3OH). IR
(cm-1): 3488 (OH), 2958 (CH2), 1570 (C=N), 1471 (N=C–S), 682
(C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm): 7.94–7.38 (m, 4H,
Ar–H), 5.02–4.22 (m, 6H, O–H), 4.35 (s, 2H, SCH2), 4.06–3.40 (m,
7H, –OCH), 2.40 (s, 3H, -CH3). 13C NMR (DMSO-d6, 75 MHz, ppm):
154.7, 154.2, 142.1, 140.2, 131.0, 129.8, 127.6, 74.3, 74.0, 71.8,
67.4, 64.7, 63.4, 22.9, 21.2. MS-ESI (m/z): 411(M+ + 1), 393, 287,
261, 259, 232, 231, 204. Elemental anal. calcd. for C17H22N4O6S: C,
49.75; H, 5.4; N, 13.65. Found: C, 49.6; H, 5.5; N, 13.4%.
6-(4-Methoxylphenyl)-3-(D-glucoheptonic-hexitol-1-yl)-7H-1,2,4-
triazolo[3,4-b][1,3,4]thiadiazine (2i): White powder, yield% 85%.
M.p. 210–212°C (from ethanol). [α]D = –13.6°(c 0.088, CH3OH).
IR (cm-1): 3337 (OH), 2920 (CH2), 1606 (C=N), 1468 (N=C–S), 700
(C–S–C). 1H NMR (DMSO-d6, 300 MHz, ppm): 8.02–7.99 (m, 2H,
Ar–H), 7.15-7.12 (m, 2H, Ar–H), 5.00 (m, 1H, O–H), 4.34–4.31 (m,
5H, O–H), 4.30 (s, 2H, SCH2), 4.25–4.07(m, 2H, –OCH), 3.86 (s, 3H,
OCH3), 3.59–3.55(m, 5H, –OCH). 13C NMR (DMSO-d6, 75 MHz,
ppm): 162.3, 154.6, 153.9, 140.2, 129.5, 126.0, 114.6, 74.3, 74.0,
71.8, 67.4, 64.7, 63.4, 55.7, 22.8. MS-ESI (m/z): 427(M+ + 1), 396,
296, 277, 247, 228, 150. Elemental anal. calcd. for C17H22N4O7S: C,
47.9; H, 5.2; N, 13.1. Found: C, 47.7; H, 5.3; N, 13.35%.
We are grateful for financial support from the Natural
Science Foundation of Zhejiang Province, China (Project No.
M203149).
Received 26 March 2007; accepted 5 May 2007
Paper 07/4561 doi: 10.3184/030823407X210901
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PAPER: 07/4561