Synthesis and biological activity of some novel derivatives of 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole

Article abstract of DOI:10.3390/12081596

To discover new 1,2,4-triazole derivatives which may possess significant biological activities, we synthesized a series of novel 6-aryl-3-(D- galactopentitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galactopentit

Full text of DOI:10.3390/12081596

Molecules 2007, 12, 1596-1605
molecules
ISSN 1420-3049
© 2007 by MDPI
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Full Paper
Synthesis and Biological Activity of Some Novel Derivatives of
4-Amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole
Jian-yu Jin 1, Li-xue Zhang 2,*, An-jiang Zhang 2, Xin-Xiang Lei 2 and Jiang-Hai Zhu 1
1
College of Education, Wenzhou University, Wenzhou 325035, P.R. China; E-mail: jjy@wzu.edu.cn
2
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325027, P.R.
China
* Author to whom correspondence should be addressed; E-mail: zhanglixuelz@yahoo.com.cn; Tel: (+86)
577-88373073; Fax: (+86) 577-88339081
Received: 30 May 2007; in revised form: 25 July 2007 / Accepted: 25 July 2007 / Published: 27 July
2007
Abstract: To discover new 1,2,4-triazole derivatives which may possess significant
biological activities, we synthesized a series of novel 6-aryl-3-(D-galactopentitol-1-yl)-
7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galacto-
pentitol-1-yl)-3-mercapto-4H-1,2,4-triazoles from 4-amino-3-(D-galactopentitol-1-yl)-5-
mercapto-1,2,4-triazole. All the title compounds were characterized by elemental analysis,
IR, 1H- and 13C-NMR. Plant growth-regulating activity tests showed that these compounds
have remarkable effects on the growth of radish and wheat.
Keywords: Galactose, 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine, 4-(arylmethylidene)amino-
5-(D-galactopentitol-1-yl)-3-mercapto-4H-1,2,4-triazole, NMR, plant growth-regulating.
Introduction
Various substituted 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines and Schiff’s bases are associated with
diverse pharmacological activities, such as analgesic, anthelmintic, antitubercular, plant growth
regulating, antiviral, antifungal and anticancer properties [1-8]. 3-Substituted-4-amino-5-mercapto-

Molecules 2007, 12
1597
1,2,4-triazole is the key intermediate in the formation of these heterocyclic compounds. Based on the
principle of activity addition, we expected to obtain reinforcement of biological activities by means of
substitutions at different positions of 3-substituted-4-amino-5-mercapto-1,2,4-triazole derivatives.
Unfortunately, the water-solubility of most these compounds was too poor for use in a clinical trial as
medicines. Attachment of a galactose residue containing five hydroxyl groups to the 3-position of the
fused heterocycle could bring about changes in its solubility; in addition, we expected that there might
be a strong affinity for the the galactose residue in organisms, resulting in special activity.
Prompted by these observations and as a continuation of the success of the attachment of a
hydroxypropyl group to the 3-position [9], we have now synthesized a series of 6-aryl-3-(D-galacto-
pentitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galacto-
pentitol-1-yl)- 3-mercapto-4H-1,2,4-triazoles, then confirmed their structures by elemental analysis, IR,
13
1H- and C-NMR, and determined the plant growth regulating effects of all the title compounds and
the key intermediate 1.
Results and Discussion
Synthesis
The synthetic route used is shown in Scheme 1. After preparing 4-amino-3-(D-galactopentitol-
1-yl)-5-mercapto-1,2,4-triazole (1), the 3,6-disubstituted 1,2,4-triazolo[3,4-b][1,3,4] thiadiazines
2a~2h were obtained through the reaction with the appropriate substituted phenacyl bromide (or
chloride), whereas the 4-(arylmethylidene)amino-5-(D-galactopentitol-1-yl)-3-mercapto-4H-1,2,4-
triazoles 3a~3h were obtained through the reaction with the appropriate substituted benzaldehyde.
The syntheses of thiocarbohydrazide and 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-
triazole (1) were carried out according to the literature methods with some improvements [9~11]. First,
we quickly raised the reaction temperature to 100~110°C for half an hour, in order to maximize the
yield of thiocarbohydrazide. Second, some water was added to the mixture when D(-)-galactonic acid
γ-lactone was reacted with thiocarbohydrazide in pyridine. Finally, the solubility of the triazole
intermediate in hot water differed noticeably from that in cold water, so the crude product was
recrystallized from water.
The reaction conditions of the two steps are mild and highly efficient. The rates of ring-closure are
closely related to the structures of the substituents R. When R contains electron-withdrawing groups,
the rates of ring-closure are increased because the electron-cloud densities of the carbonyl carbons are
lowered.
In an attempt to prepare ring closed 3,6-disubstituted-5,6-dihydrogen-1,2,4-triazolo [3,4-b][1,3,4]-
thiadiazole derivatives, we have applied a previously reported procedure [12], and treated the triazole 4
with the appropriate benzaldehyde maintaining the pH values during the reaction at 5–6, since the
acidity of the reaction medium is crucial. However, the desired intramolecular Mannich reaction did
nor occur, and we only obtained open-chain hydrazones 3a~3b, as in our previous research [13].
Consequeltly we did not adjust the pH values in the subsequent reactions, and thus obtained 3c~3h
more expediently.
Because of the successful attachment of a galactose residue to the 3-position of 1,2,4-triazole, the
fused heterocycles display increased solubility and most of the title compounds can be dissolved in

Molecules 2007, 12
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ethanol. Moreover, compounds 2e (possessing a phenyl ring without any substituent) and 3a (having a
phenyl ring with a hydroxyl group) dissolve in water, whereas compound 3e (having two galactose
residues but too large a relative molecular mass) dissolves somewhat in water and ethanol.
Scheme 1. Syntheses of the title compounds 2a~2h, 3a~3h.
HO
O
O
N
N
OH
S
OH
pyridine
H2NHNCNH NH2
HO
HO
SH
N
OH
HO
NH2
OH
OH
1
N
N
OH
OH
HO
O
S
N
CH2Br
C
N
R1
OH
OH
6
C2H5OH
R1
2a-2h
O
R2
C
H
N
NH
OH
OH
C2H5OH
HO
N
N
S
OH
OH
3a-3h
R2
OH
Cl
R2=
R1=
Cl
3a:
3b:
3c:
Cl
OCH3
2a:
2d:
2b:
2c:
Cl
F
F
F
H
3e:
3d:
3f:
2f:
C
2e:
2h:
C
H
NO2
3g:
3h:
NO2
CH3
2g:
Br
IR spectra of the title compounds
The absence of N-H, S-H and C=O absorptions in the IR spectra confirms that the
cyclocondensation to form the title compounds 2a~2h has taken place. The characteristic stretching
vibrations of the products are at 3413~3440 cm-1 (O-H, strong), 1615~1634 cm-1 (C=N). The C-S-C
bending vibrations are in the fingerprint region, around 670 cm-1. The CH2 stretching vibration bands
are observed at about 2921~2978 cm-1.

Molecules 2007, 12
1599
The absence of N-H and C=O absorption bands in the IR spectra also confirmed that the title
compounds 3a~3h have been obtained via condensation. The stretching vibration bands of OH group
are at 3261~3533 cm-1. The C-H stretching vibration bands of the CH2 groups are at 2873~2975 cm-1.
The characteristic stretching vibrations of the products are at 1582~1631cm-1 (C=N), 1234~1292 cm-1
(C=S). The absorbance band of S-H stretching vibration (2550-2650 cm-1) was not observed because
compounds 3a~3f display tautomerism between the thiol and thioketone forms and exist mainly in the
latter form [14~19].
1H-NMR spectra of the title compounds
In the 1H-NMR spectra of triazolothiadiazines 2a~2h, the characteristic downfield signal at δ 13.50
ppm attributed to the -N=C-SH (-NH-C=S of the tautomer) in compound 1 is absent, as is a sharp
signal at δ 5.53 ppm attributable to the N-NH2 group in the parent triazole. In the spectra of the title
compounds, the signal at δ 3.33~6.03 ppm is attributed to the CH2 and OH of the galactopentitol-1-yl
group. Resonance peaks at δ 7.30~8.42 ppm are attributed to the aromatic ring protons.
In all the title compounds 3a~3h, additional resonances assigned to the –CH=N- (δ 9.56─10.41
ppm) were observed, which confirmed the condensation between the amino group and the carbonyl
group. A downfield signal appearing at δ 13.51-13.92 ppm is attributed to the -NH-C=S moiety.
whereas the chemical shifts (δ values) of the SH protons are at less than 4.0 ppm, in general. All these
show the compounds 3a~3h have 4-arylmethylideneamino-5-aryl-2,4-dihydro-3H-1,2,4-triazole-
3-thione structures (D). The remaining protons resonated as multiplets in the aromatic region (δ
6.91-8.41 ppm). In typical methylideneamino groups, the methylidene hydrogen atoms display
chemical shifts in the region above δ 8.8 ppm, but in the title compounds the corresponding δ values
were in the region between 9.56 and 10.41 ppm. The triazole NH protons also showed downfield δ
values (13 ppm or so). We are confident that compounds 3a~3h exist only in an E-configuration,
which results from the deshielding effects of the keto-thione (C=S) groups’ anisotropy on the N=CH
hydrogen. The chemical shifts of N=CH hydrogen and triazole N-H hydrogen appear downfield. We
cconclude that the mechanism of this type of reaction involves an elimination to give imines, followed
by a nucleophilic substitution, and in the transition state an E-configuration would posses a lower
energy.
13C-NMR spectra of the title compounds
The key intermediate, 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole (1), exhibits
absorption peaks at δ 152.70 and 165.53 ppm, due to N-C=N and N-C=S groups, respectively, and at
δ 70.95, 69.83, 69.04, 65.67, 62.93 ppm, due to the five carbon atoms of the galactose residue.
The 13C-NMR spectra of compound 2e, for instance, exhibited the expected 13 absorption peaks,
i.e. δ 22.94, 62.91, 65.60, 68.93, 69.78, 71.31, 127.72, 129.06, 132.11, 133.27, 141.26, 154.80, 155.64.
Those at 62.91~71.31 ppm are assigned to the sugar carbons. Because of the existence of
carbon-nitrogen double bonds, the chemical shifts of the three carbon atoms in the triazole ring appear
at δ 141.26, 154.80, 155.64, which conforms approximately with the values reported in the literature
[20]. All the benzene carbons of the title compounds exhibit chemical shifts between 105.23~151.50,
whereas the peaks with δ values near 22.86~25.83 ppm are attributed to the S-CH2 in the thiadiazine

Molecules 2007, 12
1600
rings because of the influence from the ortho and para substituents of the benzene rings. The title
compounds 3a~3h show peaks at δ 151.99~165.65 ppm due to N-C=N, N-C=S and Ph-CH=N group.
The δ values differ among the title compounds resulting from the presence of phenyl groups with
different substituents.
Biological evaluation
The effects of the title compounds 1, 2a~2h, 3a~3h on sprouting of wheat and radish seeds have
been investigated. After treating with solutions of 100 μg/mL and 10 μg/mL of the title compounds for
7 days (25 °C), the germination percentages have been determined, and from the difference in length
between stems and radicles of seedlings treated with the title compounds and those treated only with
distilled water, the plant growth regulating activities have been calculated. A positive result represents
a growth increase, whereas a negative result implies an inhibition:
the length of sample’s stem/radicle － the reference’s length
× 100％
effect =
the length of reference’s stem/radicle
The results are shown in Table 1. From the data it is apparent that most of the title compounds
show a more pronounced inhibiting effect than 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-
1,2,4-triazole (1) on the growth of wheat and radish.
Table 1. Plant growth regulating activities of compounds 1, 2a~2h, 3a~3h
(germination percentage % / effect (on stem) % / effect (on root) %).
Radish
Wheat
Compd.
10 ppm
100 ppm
10 ppm
100 ppm
1
2a
100/23.5/3.8
30/-54.7/-74.9
35/-27/-52.2
20/-56.1/-77.4
25/-44.5/-61.1
65/4.9/-21.6
-100%
85/40.1/-1.3
-100%
85/-3.4/20.9
85/-74.5/-72.4
85/-41.9/-52.6
95/-79.5/-78.1
100/-69/-65.9
100/8.2/12.9
85/-95.5/-95.6
90/-52.6/-56.4
95/-15.2/-43.5
85/19/-2.0
75/-28.1/8.7
-100%
2b
-100%
-100%
2c
-100%
-100%
2d
-100%
-100%
2e
75/6.2/-28.8
-100%
80/3.1/7.3
-100%
2f
2g
35/-37.2/-65.7
15/-31.8/-58.1
30/-17.5/-34.7
5/-27.8/-77.8
5/-12.5/-61.1
5/-69.6/-91.7
15/0.3/-46.7
65/-11.6/-34.4
40/-32.9/-31.5
30/-96.4/-98.1
90/0/0
-100%
-100%
2h
-100%
95/-96.6/-96.1
85/6.9/-1.2
-100%
3a
30/-14.4/-36.7
-100%
3b
5/-18.1/-83.6
100/-85.8/-83.4
95/-91.4/-92
60/-9.5/-12.3
55/-79.4/-85.2
85/-36.1/-28.7
65/-83.8/-78.5
100/0/0
3c
5/-100/-7.2
-100%
100/-91.8/-100
75/-92.7/-100
55/-91.4/-91.6
-100%
3d
3e
15/-50.2/-78.1
-100%
3f
3g
-100%
-100%
3h
-100%
-100%
Reference
90/0/0
100/0/0

Molecules 2007, 12
1601
It was interesting to note that compound 2e showed inhibitory activities towards the growth of the
dicotyledon (radish) at two concentration levels, but under the same conditions it expressed stimulative
activities towards the growth of the monocotyledon (wheat). It has a good level of activity and is
worthy of further study to establish a relationship between structure and activity.
Experimental
General
All melting points were determined on an XT-4A melting point apparatus. The IR spectra (KBr
disks) were recorded in the 4000─400 cm-1 range on a Bruker Quinox 55 spectrophotometer. The
1H-NMR and 13C-NMR spectra were measured at 25°C on a Bruker Advance 300 spectrometer
operating at 300 and 75 MHz, respectively (DMSO-d6 solutions using TMS as internal reference).
Elemental analyses were carried out with a Flash-EA 1112 elemental analyzer. All the reagents used
were AR grade.
Preparation of 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole (1).
Pure thiocarbohydrazide was obtained by the quick heat-up method. The thiocarbohydrazide thus
prepared (1 mmol) was then added to a solution of D(-)galactono-1,4-lactone (1 mmol) in pyridine (20
mL) and water (2 mL), and the mixture was refluxed for 6 h. After removing the solvent, the white
cotton-like solid formed was recrystallized from water to give compound 1 in 69.1% yield; m.p.:
215~217 °C; IR: 3430 (OH), 3350 (NH2), and 1627(C=N) cm−1; 1H-NMR δ ppm: 3.33~5.26 (m, 11H,
13
C-H, O-H), 5.53 (s, 2H, NH2), 13.50 (s, 1H, S-H); C-NMR δ ppm: 62.93, 65.67, 69.04, 69.83 and
70.95 (galactose residue carbons), 152.70 and 165.53 (triazole ring carbons).
General method for the preparation of 6-aryl-3-(D-galactopentitol-1-yl)-7H-1,2,4-triazolo [3,4-b]
[1,3,4] thiadiazines 2a~2h
The appropriate ω-haloacetophenone (1 mmol) was added to a solution of compound 1 (1 mmol) in
75% C2H5OH (20 mL). The mixture was refluxed for 4 h. The solid obtained on concentration of the
solvent was filtered, dried and recrystallized from 75% C2H5OH to give the title compounds. The
physical and spectral data of the title compounds 2a~2h are given in Tables 2~4.
General method for the preparation of 4-(arylmethylidene)amino-5-(D-galactopentitol-1-yl)-3-
mercapto-4H- 1,2,4-triazoles 3a~3h
An appropriate aromatic aldehyde (1 mmol, distilled under reduced pressure before use) was
added to a solution of compound 1 (1 mmol) in 75% ethanol (20 mL). The mixture was stirred and
refluxed for 4 h. The solid obtained on concentration was filtered, dried and recrystallized from 75%
ethanol to give the title compounds. The physical and spectral data of the title compounds 3a~3h are
given in Tables 2~4.

Molecules 2007, 12
1602
Table 2. Physical data of compounds 2a~2h, 3a~3h.
Anal./% Found (calc.)
Molecular
formula
Compd.
Colour Yield/% M.p./°C
C
H
N
2a
2b
2c
2d
2e
2f
C15H17ClN4O5S
C15H16Cl2N4O5S
C15H17FN4O5S
C15H16F2N4O5S
C15H18N4O5S
C15H17N5O7S
C15H17BrN4O5S
C21H22N4O5S
C14H18N4O6S
C14H17ClN4O5S
C15H20N4O6S
C16H20N4O5S
C22H30N8O10S2
C14H18N4O5S
C14H17N5O7S
C15H20N4O5S
white
yellow
white
white
white
brown
white
brown
white
white
white
white
yellow
white
brown
white
75.6
68.7
79.2
66.1
49.4
48.7
57.3
61.2
68.2
72.5
71.8
72.6
75.1
65.4
63.5
75.8
195~197
101~103
208~210
175~177
200~202
178~180
183~185
103~105
206~208
218~220
221~223
192~193
218~220
203~205
228~229
220~222
45.21(44.95) 4.12(4.27) 14.31(13.98)
41.07(41.39) 3.64(3.70) 12.69(12.87)
46.78(46.87) 4.71(4.46) 14.79(14.58)
44.95(44.77) 4.25(4.01) 13.74(13.92)
49.04(49.17) 4.86(4.95) 15.17(15.29)
44.08(43.79) 4.46(4.17) 17.35(17.02)
40.22(40.46) 3.72(3.85) 12.28(12.58)
56.86(57.00) 5.24(5.01) 12.59(12.66)
45.46(45.40) 4.81(4.90) 15.25(15.13)
43.12(43.25) 4.50(4.41) 14.29(14.41)
46.98(46.87) 5.36(5.24) 14.38(14.57)
50.36(50.52) 5.47(5.30) 14.90(14.73)
41.72(41.90) 4.56(4.79) 17.82(17.77)
47.71(47.45) 5.24(5.12) 15.57(15.81)
42.21(42.10) 4.36(4.29) 17.78(17.54)
48.82(48.90) 5.31(5.47) 15.26(15.21)
2g
2h
3a
3b
3c
3d
3e
3f
3g
3h
Table 3. IR data of compounds 2a~2h, 3a~3h.
Compd.
IR (ν/cm-1)
2a
2b
2c
2d
2e
2f
3417(OH), 2978(CH2), 1634(C=N), 1511(N=C-S), 679(C-S-C).
3417(OH), 2968(CH2), 1632(C=N), 1469(N=C-S), 614(C-S-C).
3417(OH), 2921(CH2), 1630(C=N), 1453(N=C-S), 624(C-S-C).
3416(OH), 2958(CH2), 1615(C=N), 1469(N=C-S), 617(C-S-C).
3421(OH), 2921(CH2), 1630(C=N), 1470(N=C-S), 668(C-S-C).
3438(OH), 2976(CH2), 1634(C=N), 1470(N=C-S), 664(C-S-C).
3413(OH), 2934(CH2), 1631(C=N), 1465(N=C-S), 680(C-S-C).
3440(OH), 2946(CH2), 1632(C=N), 1469(N=C-S), 697(C-S-C).
3417(OH), 2936(CH2), 1621(C=N), 1277(C=S).
2g
2h
3a
3b
3c
3d
3e
3f
3415(OH), 2925(CH2), 1626(C=N), 1292(C=S).
3416(OH), 2970(CH2), 1631(C=N), 1252(C=S).
3416(OH), 2975(CH2), 1627(C=N), 1247(C=S).
3414(OH), 2921(CH2), 1622(C=N), 1273(C=S).
3261(OH), 2933(CH2), 1587(C=N), 1272(C=S).
3g
3h
3535(OH), 2873(CH2), 1582(C=N), 1234(C=S).
3363(OH), 2920(CH2), 1604(C=N), 1281(C=S).
Table 4. NMR data of compounds 2a~2h, 3a~3h.
Compd.
2a
1H-NMR (δ, ppm)
13C-NMR (δ, ppm)
3.40-6.03 (m, 13H, C-H, O-H), 7.68-8.11 (m, 22.86, 62.90, 65.91, 68.83, 69.71, 71.12,
4H, Ar-H).
129.24, 129.68, 131.86, 137.26, 141.97, 155.06,
155.65.

Molecules 2007, 12
1603
Table 4. Cont.
2b
3.37-5.12 (m, 13H, C-H, O-H), 7.61-7.88 (m, 25.83, 62.88, 65.28, 69.00, 69.81, 71.45,
3H, Ar-H). 128.01, 129.76, 132.47, 132.61, 133.39, 136.21,
140.46, 154.54, 154.64.
3.34-5.29 (m, 13H, C-H,O-H), 7.40-8.13 (m, 22.88, 62.92, 65.26, 69.02, 69.82, 71.44, 116.24,
4H, Ar-H). 130.11, 140.25, 153.49, 154.55, 162.54, 165.86.
3.33-5.25 (m, 13H, C-H,O-H), 7.30-7.94 (m, 25.06, 62.90, 65.26, 69.02, 69.83, 71.46,
2c
2d
3H, Ar-H).
105.23, 112.74, 119.57, 132.14, 140.32, 151.50,
154.61, 162.58, 165.92.
2e
2f
3.39-5.31 (m, 13H, C-H,O-H), 7.56-8.06 (m, 22.94, 62.91, 65.60, 68.93, 69.78, 71.31,
5H, Ar-H).
127.72, 129.06, 132.11, 133.27, 141.26, 154.80,
155.64.
3.35-5.76 (m, 13H, C-H,O-H), 8.22-8.42 (m, 23.01, 62.54, 66.06, 73.70, 75.71, 81.18,
4H, Ar-H).
108.36, 123.96, 128.78, 139.43, 149.13, 152.61,
153.92.
2g
2h
3a
3b
3c
3d
3e
3f
3.35-5.29 (m, 13H, C-H,O-H), 7.78-7.99 (m, 22.88, 63.08, 65.44, 69.19, 69.97, 71.57,
4H, Ar-H).
125.78, 129.72, 132.20, 132.94, 140.44, 153.70,
154.76.
3.34-5.30 (m, 13H, C-H,O-H), 7.44-8.14 (m, 23.00, 63.10, 65.43, 69.19, 70.02, 71.66,
9H, Ar-H).
127.04, 127.29, 128.42, 128.48, 129.27, 132.59,
138.99, 140.56, 143.38, 154.24, 154.74.
3.35-5.54 (m, 11H, C-H, C-OH), 6.91-7.87 (m, 62.94, 65.73, 69.08, 69.82, 70.57, 116.57,
4H, Ar-H), 10.10 (s, 1H, CH=N), 10.44 (s, 1H, 118.38, 119.58, 127.84, 134.03, 152.06, 158.37,
Ar-OH), 13.79 (s, 1H, HN-C).
160.46, 161.38.
3.32-5.29 (m, 11H, C-H, C-OH), 7.60-7.96 (m, 62.90, 65.63, 69.10, 69.81, 70.41, 129.27,
4H, Ar-H), 10.03 (s, 1H, CH=N), 13.84 (s, 1H, 130.31, 131.25, 137.09, 152.30, 161.18, 161.36.
HN-C).
3.32-5.26 (m, 11H, C-H, C-OH), 3.85-3.88 (m, 55.53, 62.89, 65.58, 69.06, 69.83, 70.39, 114.59,
3H, CH3), 7.08-7.87 (m, 4H, Ar-H), 9.73(s, 1H, 124.68, 130.65, 152.10, 161.29, 162.75, 163.26.
CH=N), 13.76 (s, 1H, HN-C).
3.35-5.26 (m, 11H, C-H, C-OH), 7.11-7.47 (m, 62.913, 65.42, 69.128, 69.76, 70.43, 123.65,
5H, Ar-H), 7.72-7.76 (m, 2H, CH=CH), 127.98, 128.98, 130.15, 135.00, 146.10, 151.99,
9.56-9.59 (d, 1H, CH=N), 13.79 (s, 1H, HN-C). 161.24, 165.65.
3.32-5.91 (m, 22H, C-H, C-OH), 7.09-7.87 (m, 62.90, 65.68, 69.11, 69.83, 70.43, 129.17,
4H, Ar-H), 10.01-10.13 (m, 2H, CH=N), 13.51 135.70, 152.43, 160.86, 161.40.
(s, 2H, HN-C).
3.31-5.27 (m, 11H, C-H, C-OH), 7.53-7.92 (m, 62.89, 65.60, 69.13, 69.84, 70.46, 128.62,
5H, Ar-H), 9.96 (s, 1H, CH=N), 13.81 (s, 1H, 129.06, 132.26, 132.45, 152.20, 161.36, 162.94.
HN-C).
3g
3h
3.45-5.32(m, 11H, C-H, C-OH), 7.85-8.41(m, 62.92, 65.69, 69.08, 69.80, 70.39, 124.20,
4H, Ar-H), 10.41(s, 1H, CH=N), 13.92(s, 1H, 129.71, 138.43, 149.37, 152.60, 158.50, 161.46.
HN-C).
2.40-2.51(m, 3H, CH 3), 3.32-5.27(m, 11H, C-H, 21.25, 62.94, 65.61, 69.17, 69.89, 70.50,
C-OH), 7.35-7.81(m, 4H, Ar-H), 9.86(s, 1H, 128.69, 129.61, 129.69, 142.81, 152.18, 161.39,
CH=N), 13.80(s, 1H, HN-C).
163.15.

Molecules 2007, 12
1604
Plant growth-regulating activity tests: materials and preparation of the test solutions
The title compounds (recrystallized three times), Tween-40, N,N-dimethylformamide (DMF),
wheat (monocotyledon) and radish (dicotyledon) seeds were used. A solution of sample (5 or 10 mg) in
Tween-40 (1 g) and DMF (3 mL) was placed in a 5 mL volumetric flask and made up to the mark with
distilled water. The blank was made up by adding Tween-40 (1 g), DMF (3 mL) and distilled water to
the fixed volume of 5 mL. Each compound was thus tested at two concentrations (10 and 100 μg/mL).
Method for plate testing the plant growth-regulating activities of compounds 1, 2a~2h, 3a~3h
Similar seeds were picked out and dipped in distilled water for 3 hours at room temperature.
Twenty seeds of each species were chosen and placed individually in Petri dishes of 9 cm diameter
containing two pieces of filter paper and a 5 mL solution of the tested compounds 1, 2a~2h, 3a~3h or
the blank, and all of them were incubated in a constant temperature room (25˚C), with a natural
photoperiod and an uninterrupted supply of sterilized distilled water. Growth measurements carried out
after a week.
Acknowledgements
This work was financially supported by the Natural Science Foundation of Zhejiang Province,
China (Project No. M203149).
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Sample Availability: Available form the authors.
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