Design, synthesis and anti-platelet aggregation activity study of ginkgolide-1,2,3-triazole derivatives

Article abstract of DOI:10.3390/molecules24112156

Ginkgolides are the major active component of Ginkgo biloba for inhibition of platelet activating factor receptor. An azide-alkyne Huisgen cycloaddition reaction was used to introduce a triazole nucleus into the target ginkgolide molecules. A series of ginkgolide-1,2,3-triazole conjugates with varied functional groups including benzyl, phenyl and heterocycle moieties was thus synthesized. Many of the designed derivatives showed potent antiplatelet aggregation activities with IC₅₀ values of 5~21 nM.

Full text of DOI:10.3390/molecules24112156

Article
Design, Synthesis and Anti-Platelet Aggregation
Activity Study of Ginkgolide-1,2,3-triazole
Derivatives
Jian Cui 1,†, Le’An Hu 1,2,†, Wei Shi , Guozhen Cui *, Xumu Zhang * and Qing-Wen Zhang *
3
3,
2,
1,
1
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences,
University of Macau, Macau 999078, China; mb65822@umac.mo (J.C.); yb67526@umac.mo (L.A.H)
Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology,
2
Shenzhen 518000, China
Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai 519041,
3
Guangdong, China; diana1354726@outlook.com (W.S.)
These authors contributed equally to the work.
†
*
Correspondence: cgzum@hotmail.com (G.C.); zhangxm@sustc.edu.cn (X.Z.); qwzhang@umac.mo (Q.-W.Z.)
Received: 07 May 2019; Accepted: 03 June 2019; Published: 7 June 2019
Abstract: Ginkgolides are the major active component of Ginkgo biloba for inhibition of platelet
activating factor receptor. An azide-alkyne Huisgen cycloaddition reaction was used to introduce a
triazole nucleus into the target ginkgolide molecules. A series of ginkgolide-1,2,3-triazole conjugates
with varied functional groups including benzyl, phenyl and heterocycle moieties was thus
synthesized. Many of the designed derivatives showed potent antiplatelet aggregation activities
with IC50 values of 5~21 nM.
Keywords: ginkgolide; platelet-activating factor receptor; inhibitor
1
. Introduction
Ginkgo biloba, also named maidenhair tree, the only surviving species from the family
Ginkgoaceae has existed for more than 180 million years, and for this reason it was called a “living
fossil” by Darwin. G. biloba has been used as a traditional Chinese medicine for a long time for the
treatment of lung weakness, asthma, coughing, cancer, etc [1,2]. Ginkgo has also been popular in the
Western world since 1965, when a German company developed from ginkgo extracts a botanical
medicine named EGB761, with various effects on central nervous system (CNS) diseases, including
Alzheimer’s disease, dementia, hypomnesia, etc [3,4]. The main components of ginkgo extracts are
terpene trilactones (including ginkgolides and bilobalide) and flavonoids [5,6]. Since flavonoids are
deemed to hardly penetrate the blood-brain barrier, it is assumed the terpene trilactones from ginkgo
extracts should be the major active components for the CNS effects and cardiovascular activity [7,8].
As a natural phospholipid agonist of the platelet activating factor of platelet activating factor receptor
(PAFR), platelet activating factor (PAF) regulates various physiological activities of the CNS and
peripheral nervous system, including platelet aggregation, blood pressure regulation, inflammation,
long-term enhancement of CNS, etc [9]. It’s reported that ginkgolides could competitively inhibit the
platelet-activating factor receptor (PAFR), resulting in the observed CNS protection and
antithrombotic effects [10,11].
To date, 10 ginkgolides (ginkgolide A~Q) [5,6,12] and two bilobalides (bilobalide and bilobanol)
13,14] have been isolated and from G. biloba and their structures elucidated. Most natural ginkgolides
[
displayed significant activity against PAFR, while the bilobalides didn’t. In particular, ginkgolide B
is the most potent PAFR antagonist discovered in nature [1]. Since the 1970s, many investigations on
the structural modifications and structure-activity relationship of ginkgolides have been conducted.
Molecules 2019, 24, 2156; doi:10.3390/molecules24112156
www.mdpi.com/journal/molecules

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It is revealed that both ring C and ring D are essential for anti-PAFR activity [15]. Substituents at the
C-7 position decrease the activity [16]. It’s noteworthy that the introduction of bulky or aromatic
substituents at 10-OH could help to increase activity against PAFR [17,18]. The 1,2,3-triazole moiety,
also known simply as triazole, acts as an important structural fragment widely used to construct new
drug molecules [19]. The triazole is an electron isostere of the amide group, which easily forms
hydrogen bonds, coordination bonds, etc., helping to form a variety of non-covalent bond
interactions with target proteins [19,20].
In this paper, a series of ginkgolide derivatives with 1,2,3-triazole moieties connected with
various benzyl, phenyl and heterocycle moieties at the C-10 position were designed and synthetized.
Their antiplatelet aggregation activities were also evaluated and several derivatives displayed more
potent inhibitory effects against PAFR than the natural ginkgolide B, with IC50 values of 5~21 nM, or
about 10 to 20 times higher than the natural compound.
2
. Results and Discussion
2
.1. Chemistry
Drugability is improved when the triazole moiety is introduced into some leads [20]. The azide-
alkyne Huisgen cycloaddition reaction, also known as the Huisgen 1,3-dipolar cycloaddition, has
been proved to be a powerful tool in construction of triazoles [21]. In this reaction, the azide moiety
reacts to a terminal alkyne group to form the triazole ring. The copper(I) catalyst improves both the
reaction rate and selectivity. A series of ginkgolide-1,2,3-triazole conjugates with varied functional
groups including benzyl, phenyl and heterocycle moieties was synthesized via this method.
1
0-O-Propargylated ginkgolide B (3) was synthesized in 65% yield by mixing ginkgolide B (1)
and 3-bromoprop-1-yne (2) with potassium carbonate in anhydrous acetonitrile for several hours
Scheme 1). 10-O-Propargylated ginkgolide A (3’) and 10-O-propargylated ginkgolide C (3’’) were
(
obtained in 32% and 69% yield, respectively from the corresponding ginkgolide A (1’) and ginkgolide
C (1’’) following the same scheme.
Scheme 1. Formation of 10-O-propargylated ginkgolides 3, 3’ and 3’’.
The target molecules, 10-substituted 1,2,3-triazole-ginkgolide B derivatives 5, were synthesized
using the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction [21] by mixing 10-O-
propargylated ginkgolide B (3) with a series of azides 4 in a three-phase solvent, using copper(I) as
catalyst (Scheme 2). The 1,2,3-triazole-ginkgolide A derivatives (5’) and 1,2,3-triazole-ginkgolide
ginkgolide C derivatives (5’’) were obtained by the same route.

Molecules 2019, 24, 2156
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Scheme 2. Formation of 10-substituted 1,2,3-triazole-ginkgolide derivatives 5, 5’ and 5’’.
Azides 4a–4ee were synthesized by firstly mixing the corresponding aniline, sodium nitrite and
concentrated hydrochloride in ethyl acetate at 0°C for 30 minutes, then adding sodium azide to the
system at room temperature and stirring for another two hours (Scheme 3) [22–24]. The resulting
products are listed in Table 1.
Scheme 3. Preparation of azides 4a–4ee.
Table 1. Synthesized azides 4a–4ee.
Entry
Azide
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
4s
4t
4u
4v
4w
Ar
Ph
2-Cl-Ph
3-Cl-Ph
Yield
77
88
91
75
72
71
87
88
62
86
91
76
62
75
92
88
74
87
78
78
65
87
74
63
77
67
87
76
79
87
68
1
2
3
4
5
6
7
8
9
4-Cl-Ph
2-Cl, 6Cl-Ph
2-Cl, 4Cl-Ph
3-Cl, 4Cl-Ph
3-F-Ph
3-CF
4-OCF
3-CF , 5-CF
3
, 4-Cl-Ph
-Ph
Ph
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
3
3
3
4-tertbutyl-Ph
3-Br-Ph
2-Me-Ph
2-OH-Ph
2-CN-Ph
3-Me-Ph
3-isopropyl-Ph
3-COOEt-Ph
3-COOH-Ph
4-Me-Ph
4-OMe-Ph
4-F-Ph
4x
4y
4z
4aa
4bb
4cc
4dd
4ee
4-Br-Ph
4-CF
3-Ph
4-NO
2
-Ph
4-COOMe-Ph
4-COOH-Ph
3-OMe,5-OMe-Ph
3-Cl, 4F-Ph
3-pyridine

Molecules 2019, 24, 2156
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Azides 4ff–4gg were synthesized by mixing the corresponding benzyl bromide and sodium
azide in DMF for two hours (Scheme 4) [22,25]. The resulting products are listed in Table 2.
Scheme 4. Preparation of azides 4ff, 4gg.
Table 2. Synthesized azides 4ff–4gg.
Entry Azide
Ar
Bn
2-Me-Bn
Yield
82
77
1
2
4ff
4gg
Following the reaction shown in Scheme 2, using 10-O-propargylated ginkgolide B 3 and azides
a-4gg, compounds 5a-5gg were obtained (Figure 1).
4
Figure 1. Structures of 10-substituted 1,2,3-triazole-ginkgolide B derivatives 5a–5gg.

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Following the reaction shown in Scheme 2, using 10-O-propargylated ginkgolide A 3’, 10-O-
propargylated ginkgolide C 3’’ and azides 4a, 4n, 4p, 4ff, 4gg, compounds 5’a-5’gg, 5’’a-5’’gg were
obtained as illustrated in Figure 2.
R
N
N
N
O
O
HO
O
O
O
O
H C
3
O
O
R =
R =
R =
R =
R =
Me
CN
Me
5'gg
5
'a
5'n
5'p
5'ff
R
N
N
N
O
O
O
HO
O
O
O
H C
3
O
OH
HO
O
R =
R =
R =
R =
R =
Me
5''n
CN
5''p
Me
5''gg
5
''a
5''ff
Figure 2. Structures of 10-substituted 1,2,3-triazole-ginkgolide A derivatives 5’a-5’gg and 10-
substituted 1,2,3-triazole-ginkgolide C derivatives 5’’a-5’’gg.
2
.2. Biology
Since ginkgolide derivatives have shown antiplatelet aggregation activities as reported before
15–18], the as-synthesized ginkgolide-1,2,3-triazole derivatives were expected to show improved
biological potency.
Firstly, the newly synthesized 10-substituted 1,2,3-triazole-ginkgolide B derivatives (5) were
[
tested by the method of Born [26,27]. The result was given in Figure 3. Which showed some of them
exhibited considerable activity better than ginkgolide B. The best results were obtained with
compounds 5a, 5n, 5p, 5ff and 5gg.

Molecules 2019, 24, 2156
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100.00%
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
1
5a 5b 5c 5d 5e 5f 5g 5h 5i 5j
k
5l 5m 5n 5o 5p 5q 5r 5s 5t 5u 5v 5w 5x 5y 5z 5aa 5bb 5cc 5dd5ee 5ff 5gg
Figure 3. Antiplatelet aggregation activities of the 10-substituted 1,2,3-triazole-ginkgolide B
derivatives. Ginkgolide B (1) was used as reference.
From the results shown above, we can preliminarily conclude that non-substituted benzyl
compound 5a) and phenyl (compound 5ff) 1,2,3-triazole conjugates have significantly enhanced
(
antiplatelet aggregation activities compared to ginkgolide B (1). We can also see that the substitution
at the meta- or/and para- positions of the benzyl group reduce the activity. Some small steric hindrance
groups (such as methyl and cyano groups) substituted at the ortho-position of the phenyl (compounds
5
n and 5p) and benzyl (compound 5gg) groups maintain or slightly reduce the activity.
In further studies, 10-substituted 1,2,3-triazole-ginkgolide A 5’ and ginkgolide C 5’’ derivatives,
having the same moieties as the most active ginkgolide B derivatives 5a, 5n, 5p, 5ff and 5gg, were
synthesized and their antiplatelet aggregation activities tested and reported as inhibition ratios at 50
nM). The results are shown in Figure 4. Some of them exhibit better activity than not only their
precursors 1’ or 1’’, but also ginkgolide B (1). The best results were obtained with compounds 5’a,
5
’ff, 5’gg and 5’’gg.
1
00.00%
9
8
7
6
5
4
3
2
1
0.00%
0.00%
0.00%
0.00%
0.00%
0.00%
0.00%
0.00%
0.00%
0.00%
1
1'
1''
5'a
5'n
5'p
5'ff
5'gg
5''a
5''n
5''p
5''ff
5''gg
Figure 4. Antiplatelet aggregation activity activities of the 10-substituted 1,2,3-triazole-ginkgolide A
and ginkgolide C derivatives. Ginkgolide B (1), ginkgolide A (1’) and ginkgolide C (1’’) were used as
reference.
The most active compounds obtained by method above, 5a, 5n, 5p, 5q, 5ff, 5gg, 5’a, 5’ff, 5’gg
and 5’’gg, were further examined in order to get their activity expressed as an IC50 value. The results
are listed in Table 3.
Table 3. In vitro antiplatelet aggregation activity study of some of ginkgolide-1,2,3-triazole
derivatives.

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PAF-induced platelet aggregation
PAF-induced platelet aggregation
Compound
1
Compound
IC50 (nM)
130.1 ± 20.0
580.4 ± 50.3
7540 ± 662
7.74 ± 1.89
20.63 ± 2.84
10.19 ± 2.03
44.33 ± 4.42
IC50 (nM)
5.31 ± 1.84
5.68 ± 0.71
18.55 ± 2.25
25.37 ± 4.25
71.47 ± 6.26
37.68 ± 4.17
5ff
5gg
5’a
5’ff
5’gg
5’’gg
1’
1’’
5a
5
5
5
n
p
q
As we can see, compounds 5a, 5p, 5ff, 5gg and 5’a display promising antiplatelet aggregation
activity with IC50 values ranging from 5-21 nM. Among them compounds 5ff and 5gg were the best
among the series of compounds, showing about a 20-fold increase in comparison with the natural
ginkgolide B (1).
In order to verify if the most active ginkgolide-1,2,3-triazole derivatives could also be considered
as potential antiplatelet aggregation therapeutics, compounds 5a, 5n, 5p, 5q, 5ff, 5gg, 5’a, 5’ff and
5
’’gg were examined to confirm their cytotoxicity using an LDH assay [28]. The results are shown in
Figure 5.
a
1
20.00%
00.00%
1
80.00%
60.00%
40.00%
20.00%
0.00%
Veh
1
5a
5n
5p
5q
5ff
5gg
5’a
5’ff
5’’gg
b
120.00%
100.00%
80.00%
60.00%
40.00%
20.00%
0.00%
Veh
1
5a
5n
5p
5q
5ff
5gg
5'a
5'ff
5''gg
Figure 5. Cytotoxicity of some of ginkgolide-1,2,3-triazole derivatives: (a) Tested at 1 μM
concentration. (b) Tested at 10 μM concentration. Ginkgolide B (1) was used as reference.
In addition, compounds 5a, 5p, 5ff, 5gg and 5’a were examined to confirm their toxicity on
platelets using the LDH assay [29]. The results are shown in Figure 6.

Molecules 2019, 24, 2156
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a
1
20.00%
00.00%
1
80.00%
60.00%
40.00%
20.00%
0.00%
Veh
1
5a
5p
5ff
5gg
5'a
b
1
20.00%
00.00%
1
80.00%
60.00%
40.00%
20.00%
0.00%
Veh
1
5a
5p
5ff
5gg
5'a
Figure 6. Toxicity on platelets of some of ginkgolide-1,2,3-triazole derivatives: (a) Tested at 1 μM
concentration. (b) Tested at 10 μM concentration. Ginkgolide B (1) was used as reference.
As shown in results above, these most active compounds did not demonstrate toxicity towards
cardiomyocytes and platelets (P > 0.05) up to 10 μM (almost two order of magnitude higher than IC50
of ginkgolide B), which suggest that they have a broad therapeutic window/safety window.
3
3
3
. Materials and Methods
.1. Compound Synthesis
.1.1. General Experimental Procedures
All solvents and reagents of analytical grade were obtained from commercial sources. Flash
chromatography was performed using silica gel (200-300 mesh, Qingdao Marine Chemical Group
Co., Qingdao, China). All reactions were monitored by TLC on silica gel plates (Merck, Darmstadt,
1
Germany). NMR spectra were recorded in CDCl
3
or DMSO at 400 or 600 MHz for H-NMR and 125
13
or 150 MHz for C-NMR on an Ascent 400 or 600 spectrometer (Bruker, Fallanden, Switzerland). The
solvent signal was used as an internal standard. ESI-MS were recorded on an 1200/MSD mass
spectrometer (Agilent, Santa Clara, CA, USA). HREIMS were recorded on a LTQ Orbitrap XL mass
spectrometer (Thermo, Bremen, Germany).
3
.1.2. General Procedures for the Preparation 10-O-propargylated Ginkgolides
Propargyl bromide (2.4 mmol) were slowly added to a mixture of ginkgolide (1, 1’ or 1’’, 2.0
mmol) and K
2
CO (4.0 mmol) in acetonitrile (15 mL). The reaction mixture was refluxed for 24 h under
3
an argon atmosphere and then was extracted with EtOAc three times. The combined organic phases

Molecules 2019, 24, 2156
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were dried over anhydrous MgSO
4
, filtered, and concentrated in vacuo. The residue was purified by
chromatography (SiO2, petroleum ether (PE)/EtOAc stepwise elution, 1:1 to EtOAc).
1
0-O-Propargylated ginkgolide B (3). Following the described procedure, 602 mg (65%) of compound 3
1
were obtained from 829 mg (2.0 mmol) of ginkgolide B (1). H-NMR (600 MHz, DMSO-d
1
2
6
) δ 6.46 (s,
H), 6.14 (s, 1H), 5.32 (d, J = 4.1 Hz, 1H), 5.19 (s, 1H), 5.15 (d, J = 4.9 Hz, 1H), 4.69 (ddd, J = 70.7, 15.8,
.5 Hz, 2H), 4.61 (d, J = 6.8 Hz, 1H), 4.09 (dd, J = 6.9, 4.9 Hz, 1H), 3.62 (t, J = 2.4 Hz, 1H), 2.84 (q, J = 7.1
Hz, 1H), 2.13 (dd, J = 13.6, 4.6 Hz, 1H), 1.99 (s, 1H), 1.87 (td, J = 13.9, 4.2 Hz, 1H), 1.71 (dd, J = 14.4, 4.5
1
3
Hz, 1H), 1.11 (d, J = 7.2 Hz, 3H), 1.05 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 176.77, 172.56, 170.63,
6
1
2
10.02, 99.51, 93.37, 83.06, 79.71, 79.29, 74.96, 74.12, 72.41, 67.84, 60.23, 57.91, 49.08, 41.96, 36.96, 32.29,
+
9.38 (3C), 8.44. HRMS (ESI): m/z calcd for C23
H
26O10 [M + H] : 463.1599, found 463.1531.
1
3
0-O-Propargylated ginkgolide A (3’), Following the described procedure, 286 mg (32%) of compound
1
’ were obtained from 797 mg (2.0 mmol) of ginkgolide A (1’). H-NMR (600 MHz, DMSO-d
6
) δ 6.43
(s, 1H), 6.12 (s, 1H), 5.10 (s, 1H), 5.00 (d, J = 4.1 Hz, 1H), 4.86 (t, J = 7.7 Hz, 1H), 4.72 (dd, J = 15.6, 2.5
Hz, 1H), 4.50 (dd, J = 15.5, 2.5 Hz, 1H), 3.59 (s, 1H), 3.17 (d, J = 5.2 Hz, 1H), 2.91 (q, J = 7.2 Hz, 1H), 2.75
(
(
9
7
dd, J = 15.1, 7.2 Hz, 1H), 2.08 (dd, J = 13.7, 4.8 Hz, 1H), 1.99 (s, 1H), 1.95 (dd, J = 13.8, 4.3 Hz, 1H), 1.82
dd, J = 15.1, 8.2 Hz, 1H), 1.72 (dd, J = 14.1, 4.8 Hz, 1H), 1.23 (s, 2H), 1.12 (d, J = 7.2 Hz, 3H), 1.03 (s,
H). 13C-NMR (150 MHz, DMSO-d
6
) δ 176.91,172.75, 170.96, 110.08, 100.94, 87.95, 86.48, 85.31, 79.49,
8.95, 75.32, 68.67, 66.83, 57.81, 49.07, 49.03, 36.78, 36.45, 32.25, 29.24 (3C), 8.64. HRMS (ESI): m/z calcd
[M + H]+: 447.1650, found 447.1582.
for C23
H26O9
1
3
0-O-Propargylated ginkgolide C (3’’). Following the described procedure, 669 mg (69%) of compound
1
’’ were obtained from 861 mg (2.0 mmol) of ginkgolide A (1’’). H-NMR (600 MHz, DMSO-d ) δ 6.47
6
(
s, 1H), 6.17 (s, 1H), 5.68 (d, J = 6.1 Hz, 1H), 5.26 (d, J = 5.0 Hz, 1H), 5.18 (s, 1H), 4.71 (ddd, J = 67.5,
5.8, 2.5 Hz, 2H), 4.59 (d, J = 6.6 Hz, 1H), 4.06–4.01 (m, 2H), 3.99 (ddd, J = 12.6 Hz, 6.1 Hz, 4.3 Hz, 1H),
1
3
2
7
.63 (s, 1H), 2.82 (q, J = 7.1 Hz, 1H), 2.50 (s, 2H), 1.99 (s, 2H), 1.54 (d, J = 12.5 Hz, 1H), 1.18 (t, J = 7.1 Hz,
H), 1.12 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ 176.73, 172.50, 170.90, 109.86, 99.26, 93.45, 83.06,
6
9.82, 79.29, 74.79, 74.17, 73.95, 67.05, 64.01, 60.23, 58.01, 49.26, 41.94, 32.20, 21.23 (3C), 8.48. HRMS
+
(
ESI): m/z calcd for C23
H
26O
11 [M + H] : 479.1548, found 479.1472.
3
.1.3. General Procedures for the Preparation of 10-Substituted 1,2,3-triazole-Ginkgolide Derivatives
Sodium ascorbate (0.03 mmol) and CuSO (0.01 mmol) were added in single portions to a
solution of 10-O-propargylated ginkgolide 3, 3’ or 3’’ (0.1 mmol) and corresponding azide 4 (0.11
mmol) in 1:1:1 t-BuOH/ H O/THF (3 mL). The reaction mixture was stirred at room temperature for
8 h under an argon atmosphere and then was extracted with EtOAc three times. The combined
organic phases were dried over anhydrous MgSO , filtered, and concentrated in vacuo. The residue
, PE/EtOAc 1:3 stepwise elution to EtOAc) to afford the
4
2
4
4
was purified by chromatography (SiO
2
appropriate compound 5.
1
0-O-(1-Phenyl-1H-1,2,3-triazole) ginkgolide B (5a). Following the described procedure, 42.3 mg (73%)
1
of compound 5a were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide B (3). H-
NMR (400 MHz, DMSO-d ) δ 8.798 (1H, s), 7.88 (d, J = 7.6 Hz, 2H), 7.50–7.64 (m, 3H), 6.47 (s, 1H), 6.20
s, 1H), 5.52 (d, J = 4.4 Hz, 1H), 5.45 (d, J = 12.0 Hz, 1H), 4.93 (d, J = 12.0 Hz, 1H), 4.63 (d, J = 6.8 Hz,
6
(
1
H), 4.21 (dd, J = 6.8 Hz, 4.8 Hz, 1H), 2.88 (q, J = 6.8 Hz, 1H), 2.11 (dd, J = 13.6 Hz, 4.0 Hz, 1H), 1.84
(
(
ddd, J = 14.0 Hz, 13.6 Hz, 4.0 Hz, 1H), 1.73 (dd, J =14.4 Hz, 4.0 Hz, 1H), 1.13 (d, J = 7.2 Hz, 3H), 1.02
s, 9H). 13C-NMR (125 MHz, DMSO-d
6) δ 176.32, 172.51, 170.12, 143.76, 136.46, 129.96 (2C), 128.94,
1
3
21.59, 120.23 (2C), 109.68, 98.88, 92.62, 82.47, 78.49, 75.16, 73.77, 71.96, 67.34, 63.00, 48.73, 41.56, 36.54,
+
1.73, 28.64 (3C), 7.84. HRMS (ESI): m/z calcd for C29
H
31N3O10 [M + H] : 582.2082, found 582.2062.
1
0-O-(1-(2-Chlorophenyl)-1H-1,2,3-triazole) ginkgolide B (5b). Following the described procedure, 21.0
mg (34%) of compound 5b were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (400 MHz, DMSO-d
6) δ 7.78 (d, J = 1.2 Hz, 1H), 7.58–7.71 (m,2H), 6.47 (s, 1H), 6.20 (s,
1
H), 5.50 (d, J = 4.8 Hz, 1H), 5.46 (d, J = 12.0 Hz, 1H), 5.33–5.35 (m, 2H), 4.97 (d, J = 12.0 Hz, 1H), 4.64

Molecules 2019, 24, 2156
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(d, J = 7.2Hz, 1H), 4.21 (dd, J = 7.2 Hz, 4.8 Hz, 1H), 2.88 (q, J = 7.0 Hz, 1H), 2.12 (dd, J = 13.6 Hz, 4.0 Hz,
1
3
1
8
H), 1.85 (ddd, J = 14.4 Hz, 13.4 Hz, 4.0 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.0 Hz,1H), 1.12 (d, J = 6.8 Hz,
H), 1.02 (s, 9H), 176.30, 172.47, 170.10, 142.91, 134.30, 131.77, 130.60, 128.52, 128.39, 128.31, 125.43,
09.67, 98.86, 92.58, 82.46, 78.47, 75.25, 73.74, 71.93, 67.32, 63.07, 48.72, 41.55, 36.51, 31.72, 28.65 (3C),
13
.57 (s,1H). C-NMR (125 MHz, DMSO-d6) δ7.82, 7.80 (d, J = 1.2Hz, 1H). HRMS (ESI): m/z calcd for
+
C
29H30ClN3O
10 [M + H] : 616.1692, found 616.1670.
1
0-O-(1-(3-Chlorophenyl)-1H-1,2,3-triazole) ginkgolide B (5c). Following the described procedure, 40.1
mg (65%) of compound 5c were obtained as method 1, from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.87 (s, 1H), 8.02 (s, 1H), 7.59–7.91
(m, 3H), 6.47 (s, 1H), 6.20 (s, 1H), 5.43–5.46 (m, 2H), 5.33 (s, 2H), 4.93 (d, J = 12.0 Hz, 1H), 4.64 (d, J =
6
1
1
1
4
6
.8 Hz, 1H), 4.20 (dd, J = 7.0 Hz, 4.6 Hz, 1H), 2.88 (q, J = 6.8 Hz, 1H), 2.11 (dd, J = 13.0 Hz, 3.8 Hz, 1H),
.86 (ddd, J = 14.2 Hz, 13.4 Hz, 3.8 Hz, 1H), 1.73 (dd, J = 14.4 Hz, 4.0 Hz, 1H), 1.12(d, J = 6.8 Hz, 3H),
.02 (s, 9H). 13C-NMR (125 MHz, DMSO-d
6) δ 176.28, 172.46, 170.08, 143.82, 137.48, 134.20, 131.69,
28.74, 121.91, 120.02, 118.84, 109.66, 98.88, 92.60, 82.47, 78.45, 75.14, 73.75, 71.93, 67.29, 62.90, 48.71,
1.53, 36.51, 31.70, 28.62 (3C), 7.82. HRMS (ESI): m/z calcd for C29
H
30ClN O10 [M + H]+: 616.1692, found
3
16.1674.
1
0-O-(1-(4-Chlorophenyl)-1H-1,2,3-triazole) ginkgolide B (5d). Following the described procedure, 20.3
mg (33%) of compound 5d were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (400 MHz, DMSO-d
6) δ8.82 (s,1H), 7.68-7.94 (dd, 4H), 6.47 (s, 1H), 6.20 (s, 1H), 5.43–
5
.48 (m, 2H), 5.32–5.33 (m, 2H), 4.92 (d, J = 8.0 Hz, 1H), 4.63 (d, J = 7.2 Hz, 1H), 4.20 (dd, J = 7.0 Hz, 4.6
Hz, 1H), 2.88 (q, J = 6.8 Hz, 1H), 2.11 (dd, J = 13.0 Hz, 3.8 Hz, 1H), 1.83 (ddd, J = 14.4Hz, 13.2Hz, 4.0
Hz, 1H), 1.73 (dd, J = 14.4 Hz, 4.0 Hz, 1H), 1.13 (d, J = 7.2 Hz, 3H), 1.02 (s, 9H). 13C-NMR (125 MHz,
DMSO-d
2.60, 82.46, 78.45, 75.16, 73.74, 71.92, 67.30, 62.93, 48.70, 41.53, 36.51, 31.70, 28.62 (3C), 7.81. HRMS
ESI): m/z calcd for C29 10 [M + H]+: 616.1692, found 616.1671.
6) δ 176.28, 172.46, 170.08, 143.87, 135.24, 133.19, 129.91 (2C), 121.90 (2C), 121.73, 109.66, 98.87,
9
(
H
30ClN O
3
1
0-O-(1-(2,6-Dichlorophenyl)-1H-1,2,3-triazole) ginkgolide B (5e). Following the described procedure,
3
4.5 mg (53%) of compound 5e were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ8.54 (s,1H), 7.68–7.81(m, 3H), 6.48 (s, 1H), 6.20 (s,
1
H), 5.47 (d, J = 12.0 Hz, 1H), 5.32–5.54 (m, 2H), 5.24 (d, J = 4.4 Hz, 1H), 4.99 (d, J = 12.4 Hz, 1H), 4.64
d, J = 7.2 Hz, 1H), 4.19 (dd, J = 7.2 Hz, 4.6 Hz, 1H), 2.87 (q, J = 7.2 Hz, 1H), 2.13 (dd, J = 13.2 Hz, 4.0
Hz, 1H), 1.84 (ddd, J = 14.2 Hz, 13.4 Hz, 4.0 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.0 Hz, 1H), 1.12 (d, J = 7.2
(
Hz, 3H), 1.03 (s, 9H). 13C-NMR (125 MHz, DMSO-d
6) δ 176.27, 172.38, 170.07, 143.11, 133.04, 132.58
(
4
6
2C), 132.42, 129.26 (2C), 125.88, 109.68, 98.82, 92.40, 82.48, 78.45, 75.51, 73.74, 71.91, 67.28, 63.20, 48.68,
+
1.54, 36.50, 31.74, 28.69 (3C), 7.80. HRMS (ESI): m/z calcd for C29
H
29Cl
2N3O
10 [M + H] : 650.1303, found
50.1287.
1
0-O-(1-(2,4-Dichlorophenyl)-1H-1,2,3-triazole) ginkgolide B (5f). Following the described procedure,
2
9.3 mg (45%) of compound 5f were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.57 (s,1H), 8.02(d, J = 2.4Hz, 1H), 7.68–7.76(m, 2H),
6
1
=
.47 (s, 1H), 6.20 (s, 1H), 5.43–5.48 (m, 2H), 5.33–5.40 (m, 2H), 4.96 (d, J = 12.4Hz, 1H), 4.63 (d, J = 7.2Hz,
H), 4.20 (dd, J = 7.2Hz, 4.8Hz, 1H), 2.88 (q, J = 6.8Hz, 1H), 2.12 (dd, J = 12.8Hz, 4.0Hz, 1H), 1.84 (ddd,J
14.2Hz, 13.2Hz, 4.0Hz, 1H), 1.74 (dd, J = 14.4Hz, 4.0Hz, 1H), 1.12(d, J = 6.8Hz, 3H), 1.02 (s, 9H). C-
13
NMR (125 MHz, DMSO-d
6) δ 176.27, 172.44, 170.07, 143.02, 135.51, 133.34, 130.16, 129.64, 129.49, 128.65,
1
2
25.51, 109.65, 98.85, 92.58, 82.45, 78.44, 75.27, 73.71, 71.91, 67.30, 63.03, 59.71, 48.69, 41.53, 36.49, 31.71,
+
8.64 (3C), 7.81. HRMS (ESI): m/z calcd for C29
H
29Cl
2N3O10 [M + H] : 650.1303, found 650.1289.
1
0-O-(1-(3,5-Dichlorophenyl)-1H-1,2,3-triazole) ginkgolide B (5g). Following the described procedure,
3
8.3 mg (34%) of compound 5g were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.92 (s,1H), 8.05 (d, J = 1.6 Hz, 2H), 7.80 (t, J = 1.6
Hz, 1H), 6.48 (s, 1H), 6.20 (s, 1H), 5.44 (d, J = 12.0 Hz,1H), 5.36 (d, J = 4.8 Hz, 1H), 5.32–5.35 (m, 2H),

Molecules 2019, 24, 2156
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4
2
.93 (d, J = 12.0 Hz, 1H), 4.63 (d, J = 7.2 Hz, 1H), 4.20 (dd, J = 7.2 Hz, 4.6Hz, 1H), 2.87 (q, J = 7.2 Hz, 1H),
.11 (dd, J = 12.8 Hz, 4.0 Hz, 1H), 1.83 (ddd,J = 14.4 Hz, 13.2 Hz, 4.0 Hz, 1H), 1.73 (dd, J = 14.4Hz, 4.0
1
3
Hz, 1H), 1.12 (d, J = 7.2 Hz, 3H), 1.02 (s, 9H). C-NMR (125 MHz, DMSO-d
6) δ 176.28, 172.43, 170.08,
1
7
43.90, 138.05, 135.26 (2C), 128.27, 122.22, 118.98, 118.88, 109.66, 98.91, 92.60, 82.49, 78.44, 75.17, 73.75,
1.93, 67.28, 62.84, 48.71, 41.52, 36.51, 31.71, 28.62 (3C), 7.84. HRMS (ESI): m/z calcd for C29
H
29Cl
2N3O10
+
[M + H] : 650.1303, found 650.1287.
1
0-O-(1-(3-Fluorophenyl)-1H-1,2,3-triazole) ginkgolide B (5h). Following the described procedure, 32.4
mg (54%) of compound 5h were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (400 MHz, DMSO-d
6) δ 7.99 (s, 1H), 7.16–7.54 (m, 4H), 6.01 (s, 1H), 5.67 (d, J = 11.6 Hz,
1
7
4
6
1
4
6
H), 5.53 (d, J = 3.6 Hz, 1H), 5.05 (d, J = 4.4Hz, 1H), 4.96 (s, 1H), 4.91 (d, J = 11.2 Hz, 1H), 4.64 (d, J =
.6 Hz, 1H), 4.40 (dd, J = 7.6 Hz, 4.4 Hz, 1H), 3.07 (q, J = 6.8 Hz, 1H), 2.84 (s, 1H), 2.28 (dd, J = 12.8 Hz,
.2 Hz, 1H), 2.05 (ddd, J = 16.8 Hz, 10.8 Hz, 4.0 Hz, 1H), 1.98 (dd, J = 14.2 Hz, 4.2 Hz, 1H), 1.30 (d, J =
13
.8 Hz, 3H), 1.13 (s, 9H). C-NMR (125 MHz, DMSO-d ) δ 176.28, 172.46, 170.08, 143.86, 137.64, 131.93,
6
21.85, 116.14, 115.66, 109.66, 107.83, 107.62, 92.60, 82.47, 78.45, 75.17, 73.75, 71.93, 67.30, 62.92, 48.71,
+
1.53, 36.51, 31.71, 28.62 (3C), 7.82. HRMS (ESI): m/z calcd for C29
H
31FN
3
O
10 [M + H] : 600.1993, found
00.2014.
1
0-O-(1-(4-Chloro-3-trifluoromethylphenyl)-1H-1,2,3-triazole) ginkgolide B (5i). Following the described
procedure, 27.9 mg (41%) of compound 5i were obtained from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.07 (s,1H), 7.70–8.09 (m, 3H), 6.01
(s, 1H,), 5.65 (d, J = 11.6 Hz, 1H), 5.52 (d, J = 4.0 Hz, 1H), 5.06 (d, J = 4.0 Hz, 1H), 4.97 (s, 1H), 4.91 (d, J
=
1
11.6 Hz, 1H), 4.62 (d, J = 8.0 Hz, 1H), 4.38 (dd, J = 7.6 Hz, 4.4 Hz, 1H), 3.07 (q, J = 7.0 Hz, 1H), 2.98 (s,
H), 2.28 (dd, J = 12.8 Hz, 4.0 Hz, 1H), 2.04 (ddd, J = 14.0 Hz, 13.2 Hz, 4.0 Hz, 1H), 1.95 (dd, J = 14.4
1
3
Hz, 4.0 Hz, 1H), 1.30 (d, J = 6.8 Hz, 3H), 1.12 (s, 9H). C-NMR (125 MHz, DMSO-d
6) δ 176.27, 172.44,
1
7
70.07, 143.99, 135.40, 133.39, 130.69, 128.15, 127.83, 125.51, 122.25, 119.60, 109.66, 98.88, 92.56, 82.47,
8.43, 75.19, 73.74, 71.93, 67.28, 62.84, 48.70, 41.53, 36.50, 31.70, 28.62 (3C), 7.82. HRMS (ESI): m/z calcd
+
for C30
H29ClF
3
N3
O
10 [M + H] : 684.1566, found 684.1544.
1
0-O-(1-(4-Trifluoromethoxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5j). Following the described
procedure, 20.6 mg (31%) of compound 5j were obtained from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.83 (s,1H), 8.03 (d, J = 9.0 Hz, 2H),
7
.65 (d, J = 8.4 Hz, 2H), 6.47 (s, 1H), 6.20 (s, 1H), 5.43–5.49 (m, 2H), 5.32–5.34 (m, 2H), 4.93 (d, J = 12.0
Hz, 1H), 4.62 (d, J = 7.2 Hz, 1H), 4.21 (dd, J = 7.2 Hz, 4.6 Hz, 1H), 2.88 (q, J = 7.0 Hz, 1H), 2.11 (dd, J =
1
1
1
7
3.2 Hz, 4.0 Hz, 1H), 1.84 (ddd, J = 14.2 Hz, 13.4 Hz, 4.0 Hz, 1H), 1.73 (dd, J = 14.4 Hz, 4.0 Hz, 1H),
.13(d, J = 7.2 Hz, 3H), 1.02 (s, 9H). 13C-NMR (125 MHz, DMSO-d
) δ 176.28, 172.46, 170.08, 148.02,
43.91, 135.30, 122.63 (2C), 122.30 (2C), 121.97, 121.00, 109.66, 98.87, 92.61, 82.46, 78.45, 75.17, 73.74,
6
1.93, 67.30, 62.94, 48.71, 41.53, 36.51, 31.70, 28.62 (3C), 7.81. HRMS (ESI): m/z calcd for C30
H
30
F3
N3O11
+
[M + H] : 666.1905, found 666.1887.
1
0-O-(1-(3,5-Ditrifluoromethylphenyl)-1H-1,2,3-triazole) ginkgolide B (5k). Following the described
procedure, 32.3 mg (45%) of compound 5k were obtained from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 9.14 (s, 1H), 8.62 (s, 2H), 8.31 (s, 1H),
6
1
.48 (s, 1H), 6.21 (s, 1H), 5.47 (d, J = 12.0 Hz, 1H), 5.35 (s, 1H), 5.30–5.33 (m, 2H), 4.96 (d, J = 12.0 Hz,
H), 4.64 (d, J = 7.2 Hz, 1H), 4.21 (dd, J = 7.2 Hz, 4.8 Hz, 1H), 2.88 (q, J = 6.8 Hz, 1H), 2.12 (dd, J = 12.8
13
Hz, 4.0 Hz,1H), 1.71–1.87 (m, 2H), 1.13 (d, J = 6.8 Hz, 3H), 1.03 (s, 9H). C-NMR (125 MHz, DMSO-d
6)
δ 176.28, 172.44, 170.07, 144.01, 137.73, 132.00 (2C), 131.73 (2C), 123.81, 122.64, 121.64, 121.07, 109.68,
9
8.90, 92.54, 82.49, 78.42, 75.22, 73.77, 71.94, 62.78, 48.71, 41.53, 36.50, 31.71, 28.63 (3C), 7.83. HRMS
+
(ESI): m/z calcd for C31
H
29F6
N3O
10 [M + H] : 718.1830, found 718.1808.
1
0-O-(1-(4-tert-Butylphenyl)-1H-1,2,3-triazole) ginkgolide B (5l). Following the described procedure,
3
5.0 mg (55%) of compound 5l were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.75 (s, 1H), 7.78 (d, J = 8.4 Hz, 2H), 7.62 (d, J = 8.8

Molecules 2019, 24, 2156
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Hz, 2H), 6.47 (s, 1H), 6.20 (s, 1H), 5.58 (d, J = 4.4 Hz, 1H), 5.44 (d, J = 12.0 Hz, 1H), 5.33 (s, 2H), 4.93 (d,
J = 12.0 Hz, 1H), 4.63 (d, J = 7.2 Hz, 1H), 4.21 (dd, J = 7.2 Hz, 4.6 Hz, 1H), 2.88 (q, J = 7.2 Hz, 1H), 2.11
(
dd, J = 13.2 Hz, 4.0 Hz, 1H), 1.83 (ddd, J = 14.4 Hz, 13.2 Hz, 4.0 Hz, 1H), 1.73 (dd, J = 14.4 Hz, 3.8 Hz,
1
3
1
1
7
H), 1.33 (s, 9H), 1.13 (d, J = 7.2 Hz, 3H), 1.01 (s, 9H). C-NMR (125 MHz, DMSO-d ) δ 176.29, 172.50,
6
70.08, 150.60, 143.60, 134.13, 126.64 (2C), 121.49, 119.98 (2C), 109.65, 98.84, 92.60, 82.43, 78.46, 75.09,
3.73, 71.93, 67.32, 62.97, 48.71, 41.54, 36.51, 34.50, 31.70, 30.95 (3C), 28.62 (3C), 7.80. HRMS (ESI): m/z
+
calcd for C33
H39N3O
10 [M + H] : 638.2708, found 638.2689.
1
0-O-(1-(3-Bromophenyl)-1H-1,2,3-triazole) ginkgolide B (5m). Following the described procedure, 38.3
mg (58%) of compound 5m were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (400 MHz, DMSO-d
6) δ 8.87 (s, 1H), 8.14 (t, J = 2.0 Hz, 1H), 7.94 (dd, J = 8.2 Hz, 1.4 Hz,
1
2
H), 7.73 (d, J = 8.4 Hz, 1H), 7.58 (t, J = 8.0 Hz, 1H), 6.47 (s, 1H), 6.20 (s, 1H), 5.43–5.46 (m, 2H), 5.33 (s,
H), 4.93 (d, J = 12.0 Hz, 1H), 4.63 (d, J = 7.2 Hz, 1H), 4.20 (dd, J = 7.2 Hz, 4.6 Hz, 1H), 2.88 (q, J = 7.2
Hz, 1H), 2.11 (dd, J = 13.2 Hz, 4.0 Hz, 1H), 1.83 (ddd, J = 14.4 Hz, 13.2 Hz, 4.0 Hz, 1H), 1.73 (dd, J =
1
1
7
4.4 Hz, 4.2 Hz, 1H), 1.12 (d, J = 7.2 Hz, 3H), 1.01 (s, 9H). 13C-NMR (125 MHz, DMSO-d
) δ 176.28,
72.46, 170.08, 143.79, 137.55, 131.90, 131.66, 122.77, 122.43, 121.92, 119.23, 109.66, 98.88, 92.60, 82.47,
6
8.45, 75.13, 73.75, 71.93, 67.29, 62.89, 48.71, 41.53, 36.51, 31.70, 28.62 (3C), 7.83. HRMS (ESI): m/z calcd
+
for C29
H31BrN3O
10 [M + H] : 660.1193, found 660.1207.
1
0-O-(1-(2-Methylphenyl)-1H-1,2,3-triazole) ginkgolide B (5n). Following the described procedure, 39.3
mg (66%) of compound 5n were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.46 (s, 1H), 7.52–7.47 (m, 2H), 7.46–7.41 (m, 2H), 6.47 (s, 1H),
6
4
1
9
1
3
5
.20(s, 1H), 5.57 (d, J = 4.6 Hz, 1H), 5.45 (d, J = 12.2 Hz, 1H), 5.35–5.33 (m, 2H), 4.97 (d, J = 12.1 Hz, 1H),
.64 (d, J = 7.2 Hz, 1H), 4.21 (dd, J = 7.2, 4.7 Hz, 1H), 2.89 (q, J = 7.0 Hz, 1H), 2.15 (s, 3H), 2.13 (dd, J =
3.7, 4.5 Hz, 1H), 1.91–1.80 (m, 1H), 1.75 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.03 (s,
H). 13C-NMR (150 MHz, DMSO-d
6) δ 176.83, 173.02, 170.63, 143.35, 136.56, 133.54, 131.90, 130.45,
27.53, 126.45, 125.28, 110.16, 99.33, 93.08, 82.94, 79.01, 75.62, 74.23, 72.43, 67.83, 63.57, 49.20, 41.90,
7.01, 32.22, 29.14 (3C), 17.84, 8.32. HRMS (ESI): m/z calcd for C30
H
34
N O10 [M + H]+: 596.2244, found
3
96.2249.
1
0-O-(1-(2-Hydroxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5o). Following the described procedure, 22.1
mg (37%) of compound 5o were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 10.59 (s, 1H), 8.51 (s, 1H), 7.60 (dd, J = 7.9, 1.6 Hz, 1H), 7.36
(
6
1
ddd, J = 8.2, 7.5, 1.7 Hz, 1H), 7.12 (dd, J = 8.2, 1.2 Hz, 1H), 7.00 (td, J = 7.8, 1.3 Hz, 1H), 6.46 (s, 1H),
.20 (s, 1H), 5.64 (d, J = 4.7 Hz, 1H), 5.45 (d, J = 12.2 Hz, 1H), 5.34–5.32 (m, 2H), 4.93 (d, J = 12.1 Hz,
H), 4.63 (d, J = 7.2 Hz, 1H), 4.22 (dd, J = 7.2, 4.5 Hz, 1H), 2.92–2.84 (m, 1H), 2.12 (dd, J = 13.3 Hz, 4.4
Hz, 1H), 1.84 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.3 Hz, 4.3 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H),
1
1
4
5
.02 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ 175.74, 171.96, 169.55, 149.06, 141.97, 129.74, 124.60,
6
24.12, 123.73, 118.97, 116.45, 109.07, 98.23, 91.99, 81.83, 77.91, 74.66, 73.13, 71.35, 66.74, 62.61, 48.10,
+
0.98, 35.93, 31.15, 28.07 (3C), 7.23. HRMS (ESI): m/z calcd for C29
H32N3O
11 [M + H] : 598.2037, found
98.2051.
1
0-O-(1-(2-Cyanophenyl)-1H-1,2,3-triazole) ginkgolide B (5p). Following the described procedure, 25.5
mg (42%) of compound 5p were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.74 (s, 1H), 8.16 (dd, J = 7.8, 1.3 Hz, 1H), 7.98 (td, J = 7.9, 1.4
Hz, 1H), 7.90–7.86 (m, 1H), 7.79 (td, J = 7.7, 1.1 Hz, 1H), 6.49 (s, 1H), 6.20 (s, 1H), 5.48 (d, J = 12.4 Hz,
2
2
1
1
7
H), 5.37–5.30 (m, 2H), 4.99 (d, J = 12.3 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.22 (d, J = 7.1 Hz, 1H), 2.92–
.85 (m, 1H), 2.11 (dd, J = 13.5, 4.5 Hz, 1H), 1.86 (dt, J = 13.7, 7.0 Hz, 1H), 1.74 (dd, J = 14.4, 4.5 Hz, 1H),
.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ 176.81, 172.97, 170.63, 144.21,
6
38.10, 135.41, 135.30, 130.92, 126.18, 124.91, 116.22, 110.16, 107.43, 99.41, 93.18, 82.97, 79.00, 75.76,
4.22, 72.41, 67.82, 63.48, 49.20, 42.04, 37.01, 32.22, 29.13 (3C), 8.35. HRMS (ESI): m/z calcd for
+
C
30H31N4O
10 [M + H] : 607.2040, found 607.2050.

Molecules 2019, 24, 2156
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1
0-O-(1-(3-Methylphenyl)-1H-1,2,3-triazole) ginkgolide B (5q). Following the described procedure, 26.8
mg (45%) of compound 5q were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.78 (s, 1H), 7.72 (t, J = 2.6 Hz, 1H), 7.68–7.63 (m, 1H), 7.50 (t, J
=
7.8 Hz, 1H), 7.34 (d, J = 7.6 Hz, 1H), 6.47 (s, 1H), 6.20 (s, 1H), 5.50 (d, J = 4.5 Hz, 1H), 5.44 (d, J = 12.1
Hz, 1H), 5.33 (d, J = 4.8 Hz, 2H), 4.93 (d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.22–4.18 (m, 1H),
2
1
1
8
.88 (q, J = 7.1 Hz, 1H), 2.42 (s, 3H), 2.11 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.83 (td, J = 13.8 Hz, 4.2 Hz, 1H),
.74 (dd, J = 14.4, 4.3 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ
75.72, 171.93, 169.53, 143.06, 139.14, 135.83, 129.16, 128.93, 120.98, 120.04, 116.73, 109.08, 98.26, 92.00,
6
1.87, 77.89, 74.53, 73.16, 71.35, 66.72, 62.36, 48.11, 40.97, 35.93, 31.13, 28.04 (3C), 20.32, 7.25. HRMS
+
(ESI): m/z calcd for C30
H
34N
3O
10 [M + H] : 596.2244, found 596.2255.
1
0-O-(1-(3-Isopropylphenyl)-1H-1,2,3-triazole) ginkgolide B (5r). Following the described procedure, 34.3
mg (55%) of compound 5r were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.81 (s, 1H), 7.75 (t, J = 1.8 Hz, 1H), 7.68–7.67 (m, 1H), 7.53 (t, J
=
7.9 Hz, 1H), 7.41 (d, J = 7.7 Hz, 1H), 6.50 (s, 1H), 6.20 (s, 1H), 5.54 (d, J = 4.6 Hz, 1H), 5.45 (d, J = 12.1
Hz, 1H), 5.34 (d, J = 3.4 Hz, 2H), 4.94 (d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.22 (dd, J = 7.1 Hz,
4
1
.5 Hz, 1H), 3.06–2.99 (m, 1H), 2.89 (q, J = 7.0 Hz, 1H), 2.12 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.83 (td, J =
3.8, 4.2 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.3 Hz, 1H), 1.27 (d, J = 6.9 Hz, 6H), 1.13 (d, J = 7.1 Hz, 3H), 1.02
13
(s, 9H). C-NMR (150 MHz, DMSO-d
6) δ 176.83, 173.02, 170.63, 150.14, 144.04, 136.99, 130.39, 127.50,
1
3
6
22.12, 118.67, 118.27, 110.16, 99.35, 93.06, 82.94, 78.99, 75.60, 74.25, 72.44, 67.81, 63.41, 49.19, 42.04,
+
7.00, 33.87, 32.20, 29.11 (3C), 24.11 (2C), 8.32. HRMS (ESI): m/z calcd for C32
H
38N3O10 [M + H] :
24.2557, found 624.2565.
1
0-O-(1-(3-Ethylcarboxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5s). Following the described procedure,
1
7.6 mg (27%) of compound 5s were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.94 (s, 1H), 8.40 (s, 1H), 8.18 (dd, J = 8.1, 0.8 Hz,
1
1
H), 8.08 (dd, J = 7.8, 0.9 Hz, 1H), 7.79 (t, J = 8.0 Hz, 1H), 6.49 (s, 1H), 6.21 (s, 1H), 5.48 (d, J = 4.6 Hz,
H), 5.46 (d, J = 12.2 Hz, 1H), 5.36–5.31 (m, 2H), 4.95 (d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.38
(q, J = 7.1 Hz, 2H), 4.22 (dd, J = 7.1, 4.6 Hz, 1H), 2.89 (q, J = 7.0 Hz, 1H), 2.11 (dd, J = 13.4 Hz, 4.4 Hz,
1
H), 1.84 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.36 (t, J = 7.1 Hz, 3H), 1.13 (d,
13
J = 7.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d
6) δ 176.81, 173.00, 170.61, 165.21, 144.41,
1
6
C
37.17, 132.08, 131.16, 129.77, 125.17, 122.46, 120.88, 110.16, 99.37, 93.11, 82.96, 78.98, 75.64, 74.23, 72.43,
7.80, 63.39, 61.85, 49.20, 42.04, 37.00, 32.21, 29.12 (3C), 14.59, 8.34. HRMS (ESI): m/z calcd for
+
32H36N3O
12 [M + H] : 654.2299, found 654.2309.
1
0-O-(1-(3-Carboxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5t). Following the described procedure, 15.6
mg (25%) of compound 5t were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 13.45 (s, 1H), 8.94 (s, 1H), 8.38 (s, 1H), 8.16–8.14 (m, 1H), 8.11–
7
.99 (m, 1H), 7.76 (t, J = 7.9 Hz, 1H), 6.47 (s, 1H), 6.21 (s, 1H), 5.47–5.44 (m, 2H), 5.35–5.28 (m, 2H), 4.94
(d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.1 Hz, 4.6 Hz, 1H), 2.89 (q, J = 7.1 Hz, 1H),
2
1
1
7
.11 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.84 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.4 Hz, 1H),
.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ 176.81, 173.01, 170.62, 166.75,
44.21, 136.99, 133.01, 130.95, 129.88, 124.72, 122.30, 120.85, 110.07, 99.24, 92.99, 82.94, 78.93, 75.54,
6
4.21, 72.38, 67.74, 63.34, 49.20, 42.04, 36.74, 32.20, 29.12 (3C), 8.26. HRMS (ESI): m/z calcd for
+
C
30H32N3O
12 [M + H] : 626.1986, found 626.1998.
1
0-O-(1-(4-Methylphenyl)-1H-1,2,3-triazole) ginkgolide B (5u). Following the described procedure, 31.5
mg (53%) of compound 5u were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
B (3). H-NMR (600 MHz, DMSO-d
1
6) δ 8.75 (s, 1H), 7.76 (d, J = 8.4 Hz, 2H), 7.42 (d, J = 8.1 Hz, 2H), 6.46
(s, 1H), 6.20 (s, 1H), 5.53 (d, J = 4.6 Hz, 1H), 5.44 (d, J = 12.2 Hz, 1H), 5.33 (d, J = 3.2 Hz, 2H), 4.92 (d, J
=
3
1
12.1 Hz, 1H), 4.63 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.2, 4.6 Hz, 1H), 2.88 (q, J = 7.0 Hz, 1H), 2.39 (s,
H), 2.11 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.83 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.73 (dd, J = 14.4 Hz, 4.3 Hz,
13
H), 1.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 175.72, 171.94, 169.52, 142.94,
6

Molecules 2019, 24, 2156
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1
6
37.81, 133.34, 129.57 (2C), 120.81, 119.40 (2C), 109.01, 98.21, 91.97, 81.84, 77.84, 74.37, 73.03, 71.26,
6.65, 62.28, 47.99, 40.81, 35.83, 30.92, 28.04 (3C), 19.99, 7.01. HRMS (ESI): m/z calcd for C30
H34
N3O10
+
[M + H] : 596.2244, found 596.2251.
1
0-O-(1-(4-Methoxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5v). Following the described procedure, 20.8
mg (34%) of compound 5v were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.69 (s, 1H), 7.78 (d, J = 9.0 Hz, 2H), 7.15 (d, J = 9.1 Hz, 2H), 6.47
(s, 1H), 6.20 (s, 1H), 5.57 (d, J = 4.6 Hz, 1H), 5.44 (d, J = 12.1 Hz, 1H), 5.33 (s, 2H), 4.92 (d, J = 12.1 Hz,
1
H), 4.63 (d, J = 7.2 Hz, 1H), 4.21 (dd, J = 7.2, 4.6 Hz, 1H), 3.84 (s, 3H), 2.88 (q, J = 7.1 Hz, 1H), 2.11 (dd,
J = 13.4 Hz, 4.4 Hz, 1H), 1.83 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.3 Hz, 1H), 1.13 (d, J =
1
3
7
1
4
.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 176.83, 173.02, 170.63, 159.92, 144.00, 130.31,
6
22.40 (2C), 121.94, 115.42 (2C), 110.16, 99.34, 93.08, 82.93, 79.00, 75.43, 74.13, 72.34, 67.75, 63.27, 55.84,
9.09, 41.96, 36.94, 32.01, 28.95 (3C), 8.19. HRMS (ESI): m/z calcd for C30
+
H
34N
3
O
11 [M + H] : 612.2193,
found 612.2205.
1
0-O-(1-(4-Fluorophenyl)-1H-1,2,3-triazole) ginkgolide B (5w). Following the described procedure, 13.5
mg (22%) of compound 5w were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.69 (s, 1H), 7.93–7.89 (m, 2H), 7.49–7.44 (m, 2H), 6.64 (s, 1H),
6
.19 (s, 1H), 5.63 (d, J = 4.5 Hz, 1H), 5.46 (d, J = 12.2 Hz, 1H), 5.37 (d, J = 4.1 Hz, 1H), 5.31 (s, 1H), 4.97
(d, J = 12.2 Hz, 1H), 4.65 (d, J = 7.1 Hz, 1H), 4.24 (dd, J = 7.1 Hz, 4.4 Hz, 1H), 2.91 (q, J = 7.1 Hz, 1H),
2
1
.14 (dd, J = 13.5 Hz, 4.5 Hz, 1H), 1.86 (td, J = 13.9 Hz, 4.2 Hz, 1H), 1.75 (dd, J = 14.4 Hz, 4.5 Hz, 1H),
13
.15 (d, J = 7.1 Hz, 3H), 1.03 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 177.01, 172.98, 170.81, 162.28 (d,
6
JC-F = 246.4 Hz), 144.27, 133.33 (d, JC-F = 2.5 Hz), 123.18 (d, JC-F = 8.9 Hz, 2C), 122.14, 117.30 (d, JC-F = 23.3
Hz, 2C), 110.18, 99.41, 93.08, 82.95, 79.16, 75.63, 74.28, 72.44, 67.85, 63.41, 49.21, 42.02, 36.95, 32.11,
+
2
9.03 (3C), 7.94. HRMS (ESI): m/z calcd for C29
H
31FN3O
10 [M + H] : 600.1993, found 600.2010.
1
0-O-(1-(4-Bromophenyl)-1H-1,2,3-triazole) ginkgolide B (5x). Following the described procedure, 18.5
mg (28%) of compound 5x were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.83 (s, 1H), 7.88–7.85 (m, 2H), 7.85–7.81 (m, 2H), 6.47 (s, 1H),
6
.20 (s, 1H), 5.47 (d, J = 4.6 Hz, 1H), 5.45 (d, J = 12.2 Hz, 1H), 5.33 (d, J = 4.1 Hz, 1H), 4.93 (d, J = 12.1
Hz, 1H), 4.63 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.1 Hz, 4.6 Hz, 1H), 2.88 (q, J = 7.1 Hz, 1H), 2.11 (dd, J =
3.4 Hz, 4.4 Hz, 1H), 1.83 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.3 Hz, 1H), 1.13 (d, J = 7.1
1
13
Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d
6) δ 176.80, 172.99, 170.60, 144.39, 136.14, 133.35
(
4
6
2C), 122.63 (2C), 122.20, 122.09, 110.16, 99.36, 93.10, 82.96, 78.97, 75.65, 74.23, 72.42, 67.79, 63.33, 49.02,
+
1.91, 36.81, 32.10, 28.98 (3C), 8.26. HRMS (ESI): m/z calcd for C29
H
31BrN3O10 [M + H] : 660.1193, found
60.1208.
1
0-O-(1-(4-Trifluoromethylphenyl)-1H-1,2,3-triazole)ginkgolide
B
(5y). Following the described
procedure, 20.1 mg (31%) of compound 5y were obtained from 46.2 mg (0.1 mmol) of 10-O-
propargylated ginkgolide B (3). H-NMR (600 MHz, DMSO-d
1
6) δ 8.95 (s, 1H), 8.15 (d, J = 8.4 Hz, 2H),
8
5
.02 (d, J = 8.6 Hz, 2H), 6.47 (s, 1H), 6.21 (s, 1H), 5.47 (d, J = 12.2 Hz, 1H), 5.45 (d, J = 4.6 Hz, 1H), 5.35–
.32 (m, 2H), 4.95 (d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.1 Hz, 4.6 Hz, 1H), 2.89 (q,
J = 7.1 Hz, 1H), 2.11 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.84 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4
1
3
Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d
6) δ 176.81, 172.98,
1
1
3
70.61, 144.59, 139.72, 129.34 (q, JC-F = 32.1 Hz), 127.78 (q, JC-F = 3.6 Hz, 2C), 124.27 (q, J = 270.5 Hz),
22.50, 121.21 (2C), 110.16, 99.38, 93.12, 82.97, 78.97, 75.68, 74.24, 72.42, 67.80, 63.39, 49.19, 42.04, 37.01,
+
2.21, 29.12 (3C), 8.34. HRMS (ESI): m/z calcd for C30
H
31F3N3O
10 [M + H] : 650.1962, found 650.1967.
1
0-O-(1-(4-Nitrophenyl)-1H-1,2,3-triazole) ginkgolide B (5z). Following the described procedure, 21.9 mg
(35%) of compound 5z were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide B
1
(3). H-NMR (600 MHz, DMSO-d
6) δ 9.00 (s, 1H), 8.49–8.47 (m, 2H), 8.23–8.20 (m, 2H), 6.47 (s, 1H),
6
1
.20 (d, J = 6.2 Hz, 1H), 5.46 (t, J = 12.2 Hz, 1H), 5.40 (d, J = 4.6 Hz, 1H), 5.36–5.32 (m, 2H), 4.95 (d, J =
2.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.1 Hz, 4.6 Hz, 1H), 2.93–2.84 (m, 1H), 2.11 (dd, J =

Molecules 2019, 24, 2156
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1
3.4 Hz, 4.4 Hz, 1H), 1.84 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1
13
Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d
6
) δ 176.79, 172.97, 170.60, 147.38, 144.82, 141.16,
1
4
6
26.13 (2C), 122.76, 121.30 (2C), 110.16, 99.39, 93.14, 82.98, 78.96, 75.74, 74.23, 72.41, 67.79, 63.37, 49.19,
+
2.04, 37.01, 32.22, 29.13 (3C), 8.35. HRMS (ESI): m/z calcd for C29
H31N4O
12 [M + H] : 627.1938, found
27.1948.
1
0-O-(1-(4-Methylcarboxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5aa). Following the described
procedure, 18.5 mg (29%) of compound 5aa were obtained from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3), H-NMR (600 MHz, DMSO-d
6) δ 8.94 (s, 1H), 8.20–8.16 (m, 2H), 8.09–
8
2
.06 (m, 2H), 6.47 (s, 1H), 6.21 (s, 1H), 5.46 (d, J = 12.2 Hz, 1H), 5.42 (d, J = 4.6 Hz, 1H), 5.36–5.28 (m,
H), 4.94 (d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.1 Hz, 4.6 Hz, 1H), 3.90 (s, 3H), 2.88
(
q, J = 7.1 Hz, 1H), 2.11 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.84 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.74 (dd, J = 14.4
1
3
Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d
6) δ 176.80, 172.98,
1
7
70.60, 165.79, 144.58, 140.11, 131.53 (2C), 130.08, 122.40, 120.57 (2C), 110.16, 99.38, 93.12, 82.97, 78.97,
5.71, 74.23, 72.42, 67.79, 63.41, 52.64, 49.03, 42.04, 36.70, 32.12, 28.90 (3C), 8.29. HRMS (ESI): m/z calcd
+
for C31
H34N3
O
12 [M + H] : 640.2142, found 640.2154.
1
1
0-O-(1-(4-Carboxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5bb). Following the described procedure,
6.3 mg (26%) of compound 5bb were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.88 (s, 1H), 8.16 (d, J = 8.4 Hz, 2H), 8.16 (d, J = 8.4
Hz, 2H), 6.50 (s, 1H), 6.19 (s, 1H), 5.49–5.44 (m, 2H), 5.35–5.32 (m, 2H), 4.94 (d, J = 12.0 Hz, 1H), 4.63
d, J = 7.2 Hz, 1H), 4.21 (dd, J = 7.2 Hz, 4.2 Hz, 1H), 2.88 (q, J = 7.2 Hz, 1H), 2.11 (dd, J = 13.4 Hz, 4.4
Hz, 1H), 1.83 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.73 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H),
(
1
3
1
1
3
6
.02 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 176.84, 172.98, 170.50, 166.86, 144.40, 139.78, 131.60 (2C),
6
31.29, 122.20, 120.28 (2C), 109.95, 99.28, 93.09, 82.95, 79.01, 75.55, 74.25, 72.32, 67.76, 63.29, 49.16, 41.92,
6.87, 32.10, 29.11 (3C), 8.25. HRMS (ESI): m/z calcd for C30
+
H32
N3O
12 [M + H] : 626.1986, found
26.1998.
1
0-O-(1-(3,5-Dimethoxyphenyl)-1H-1,2,3-triazole) ginkgolide B (5cc). Following the described procedure,
2
2.5 mg (35%) of compound 5cc were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.79 (s, 1H), 7.05 (d, J = 2.4 Hz, 2H), 6.63 (t, J = 2.4
Hz, 1H), 6.52 (s, 1H), 6.18 (s, 1H), 5.52 (s, J = 4.2 Hz, 1H), 5.43 (d, J = 12.0 Hz, 1H), 5.34 (d, J = 4.2 Hz,
H), 5.32 (s, 1H), 4.92 (d, J = 12.0 Hz, 1H), 4.63 (d, J = 7.2 Hz, 1H), 4.22 (dd, J = 7.2 Hz, 4.2 Hz, 1H), 3.84
s, 6H), 2.88 (q, J = 7.2 Hz, 1H), 2.11 (dd, J = 13.4 Hz, 4.4 Hz, 1H), 1.83 (td, J = 13.8, 4.2 Hz, 1H), 1.73
dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ
76.87, 173.00, 170.66, 161.70 (2C), 144.08, 138.40, 122.15, 110.17, 100.86, 99.37, 98.98 (2C), 93.05, 82.94,
1
(
(
6
1
7
9.03, 75.60, 74.26, 72.43, 67.81, 63.37, 56.21 (2C), 49.20, 42.03, 36.98, 32.17, 29.09 (3C), 8.31. HRMS (ESI):
+
m/z calcd for C31
H
36N3O12 [M + H] : 642.2299, found 642.2308.
1
0-O-(1-(3-Chloro-4-fluorophenyl)-1H-1,2,3-triazole) ginkgolide B (5dd). Following the described
procedure, 29.2 mg (46%) of compound 5dd were obtained from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.83 (s, 1H), 8.20–8.18 (m, 1H), 8.00–
7
1
4
1
.88 (m, 1H), 7.75–7.60 (m, 1H), 6.48 (s, 1H), 6.20 (s, 1H), 5.46–5.41 (m, 2H), 5.33 (s, 2H), 4.93 (d, J =
2.0 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.23–4.17 (m, 1H), 2.88 (q, J = 7.2 Hz, 1H), 2.11 (dd, J = 13.4 Hz,
.4 Hz, 1H), 1.83 (td, J = 13.8 Hz, 4.2 Hz, 1H), 1.73 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H),
+
.02 (s, 9H). HRMS (ESI): m/z calcd for C29
H
30ClFN
3
O
10 [M + H] : 634.1604, found 634.1619.
1
0-O-(1-(3-Pyridinyl)-1H-1,2,3-triazole) ginkgolide B (5ee). Following the described procedure, 45.7 mg
(
67%) of compound 5ee were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide B
3). H-NMR (600 MHz, DMSO-d
1
(
6) δ 9.13 (d, J = 2.5 Hz, 1H), 8.88 (s, 1H), 8.71 (d, J = 4.8 Hz, 1H), 8.35–
8
1
.30 (m, 1H), 7.68 (dd, J = 8.4, 4.8 Hz, 1H), 6.49 (s, 1H), 6.21 (s, 1H), 5.49 (d, J = 4.8 Hz, 1H), 5.47 (d, J =
2.0 Hz, 1H), 5.34 (d, J = 3.2 Hz, 2H), 4.95 (d, J = 12.1 Hz, 1H), 4.64 (d, J = 7.1 Hz, 1H), 4.21 (dd, J = 7.1
Hz, 4.5 Hz, 1H), 2.88 (q, J = 7.0 Hz, 1H), 2.12 (dd, J = 13.5 Hz, 4.5 Hz, 1H), 1.85 (td, J = 13.8 Hz, 4.2 Hz,

Molecules 2019, 24, 2156
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1
3
1
d
8
H), 1.74 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.03 (s, 9H). C-NMR (150 MHz, DMSO-
) δ 176.80, 172.99, 170.59, 150.41, 144.45, 141.84, 133.59, 128.59, 125.10, 122.47, 110.07, 99.32, 92.92,
6
2.84, 78.99, 75.45, 73.96, 72.07, 67.61, 63.29, 48.94, 42.04, 36.71, 31.75, 29.12 (3C), 8.16. HRMS (ESI): m/z
+
calcd for C28
H31N4O
10 [M + H] : 583.2040, found 583.2056.
1
0-O-(1-Benzyl-1H-1,2,3-triazole) ginkgolide B (5ff). Following the described procedure, 42.8 mg (72%)
1
of compound 5ff were obtained from 46.2 mg (0.1 mmol) of 10-O-propargylated ginkgolide B (3). H-
NMR (600 MHz, DMSO-d ) δ 8.17 (s, 1H), 7.41–7.30 (m, 5H), 6.47 (s, 1H), 6.17 (s, 1H), 5.64 (d, J = 4.4
Hz, 1H), 5.61 (s, 2H), 5.35–5.31 (m, 2H), 5.27 (s, 1H), 4.84 (d, J = 12.1 Hz, 1H), 4.62 (d, J = 7.2 Hz, 1H),
6
4
1
.17 (dd, J = 7.1 Hz, 4.5 Hz, 1H), 2.86 (q, J = 7.0 Hz, 1H), 2.09 (dd, J = 12.9 Hz, 3.9 Hz, 1H), 1.77 (td, J =
1
3
3.8 Hz, 4.2 Hz, 1H), 1.70 (dd, J = 14.4 Hz, 4.4 Hz, 1H), 1.12 (d, J = 7.1 Hz, 3H), 0.98 (s, 9H). C-NMR
) δ 176.83, 172.99, 170.62, 143.50, 136.17, 129.26 (2C), 128.69, 128.48 (2C), 123.01,
(150 MHz, DMSO-d
6
1
09.77, 98.98, 92.78, 82.56, 78.85, 75.51, 74.03, 72.28, 67.54, 63.16, 53.19, 48.92, 41.92, 36.77, 31.99, 28.81
+
(3C), 8.15. HRMS (ESI): m/z calcd for C30
H
34N3O
10 [M + H] : 596.2244, found 596.2266.
1
0-O-(((Anthracen-2-yloxy)methyl)-1H-1,2,3-triazole) ginkgolide B (5gg). Following the described
procedure, 43.5 mg (70%) of compound 5gg were obtained from 46.2 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide B (3). H-NMR (600 MHz, DMSO-d
6) δ 8.22 (s, 1H), 7.93 (dd, J = 7.8 Hz, 1.3
Hz, 1H), 7.73 (td, J = 7.7 Hz, 1.4 Hz, 1H), 7.58 (td, J = 7.7 Hz, 1.2 Hz, 1H), 7.38 (dd, J = 7.9 Hz, 1.1 Hz,
1
3
1
H), 6.45 (s, 1H), 6.17 (s, 1H), 5.83 (s, 2H), 5.58 (d, J = 4.6 Hz, 1H), 5.36 (d, J = 12.2 Hz, 1H), 5.31 (d, J =
.9 Hz, 1H), 5.28 (s, 1H), 4.86 (d, J = 12.1 Hz, 1H), 4.61 (d, J = 7.2 Hz, 1H), 4.17 (dd, J = 7.2 Hz, 4.2 Hz,
H), 4.03 (q, J = 7.1 Hz, 1H), 2.87 (q, J = 7.1 Hz, 1H), 2.50 (s, 2H), 2.09 (dd, J = 13.0 Hz, 4.1 Hz, 1H), 1.99
13
(s, 2H), 1.83–1.68 (m, 2H), 1.18 (t, J = 7.1 Hz, 2H), 1.12 (d, J = 7.1 Hz, 3H), 0.98 (s, 9H). C NMR (150
MHz, DMSO-d
6) δ 176.91, 172.97, 170.70, 143.52, 138.80, 134.36, 133.90, 130.22, 129.89, 124.13, 117.45,
1
2
11.79, 110.15, 99.32, 82.87, 79.06, 75.62, 74.19, 72.42, 67.81, 63.54, 60.34, 51.71, 49.15, 42.02, 36.92, 32.12,
+
9.04(3C), 8.25. HRMS (ESI): m/z calcd for C31
H32N4O
10 [M + H] : 621.2198, found 621.2170.
10-O-(1-Phenyl-1H-1,2,3-triazole) ginkgolide A (5’a). Following the described procedure, 36.2 mg (64%)
of compound 5’a were obtained from 44.6 mg (0.1 mmol) of 10-O-propargylated ginkgolide A (3’).
1
H-NMR (600 MHz, DMSO-d
.15 (s, 1H), 5.36 (d, J = 12.0 Hz, 1H), 5.23 (s, 1H), 4.95 (d, J = 4.0 Hz, 1H), 4.89 (d, J = 11.9 Hz, 1H), 4.83
dd, J = 8.4 Hz, 7.3 Hz, 1H), 3.85–3.71 (m, 2H), 3.62–3.56 (m, 1H), 3.17 (d, J = 5.3 Hz, 1H), 2.95 (q, J = 7.1
Hz, 1H), 2.75 (dd, J = 15.1 Hz, 7.2 Hz, 1H), 2.04 (dd, J = 13.6 Hz, 5.0 Hz, 1H), 2.01–1.91 (m, 2H), 1.91–
6
) δ 8.51 (s, 1H), 7.48 (s, 2H), 7.43 (d, J = 16.7 Hz, 2H), 6.45–6.32 (m, 1H),
6
(
13
1
.80 (m, 2H), 1.79–1.70 (m, 3H), 1.70–1.63 (m, 1H), 1.13 (d, J = 7.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150
MHz, DMSO-d ) δ 176.98, 173.22, 171.05, 144.45, 130.41(2C), 122.91, 120.67(2C), 110.14, 100.81, 87.96,
6.50, 85.31, 75.74, 68.63, 66.81, 66.19, 63.35, 49.16, 36.78, 36.45, 33.62, 32.19, 29.17(3C), 23.75, 8.59.
6
8
+
HRMS (ESI): m/z calcd for C29
H
31N
3
O [M + H] : 566.2133, found 566.2111.
9
1
0-O-(1-(2-Methylphenyl)-1H-1,2,3-triazole) ginkgolide A (5’n). Following the described procedure,
4
0.0 mg (69%) of compound 5’n were obtained from 44.6 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide A (3’). H-NMR (600 MHz, DMSO-d
6) δ 8.51 (s, 1H), 7.52–7.48 (m, 2H), 7.44 (dd, J = 2.2, 1.0
Hz, 2H), 6.40 (s, 1H), 6.15 (s, 1H), 5.40–5.33 (m, 2H), 5.23 (s, 1H), 4.95 (d, J = 4.1 Hz, 1H), 4.89 (d, J =
1
=
7
1
4
5
1.9 Hz, 1H), 4.83 (d, J = 1.1 Hz, 1H), 3.82–3.75 (m, 2H), 3.60 (s, 1H), 3.17 (d, J = 5.3 Hz, 1H), 2.95 (d, J
7.2 Hz, 1H), 2.75 (dd, J = 15.1 Hz, 7.2 Hz, 1H), 2.15 (s, 3H), 1.97 (s, 1H), 1.78–1.69 (m, 3H), 1.13 (d, J =
13
.1 Hz, 3H), 1.02 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 176.97, 173.19, 171.05, 143.65, 136.71, 133.55,
6
31.87, 130.34, 127.50, 126.51, 126.03, 110.13, 100.79, 97.64, 87.94, 86.50, 85.35, 75.74, 67.49, 63.53, 49.07,
+
1.66, 40.47, 36.78, 32.20, 29.16(3C), 17.87, 8.59. HRMS (ESI): m/z calcd for C30
H
33N3O
9
[M + H] :
80.2197, found 580.2266.
1
0-O-(1-(2-Cyanophenyl)-1H-1,2,3-triazole) ginkgolide A (5’p)., Following the described procedure, 34.3
mg (58%) of compound 5’p were obtained from 446 mg (0.1 mmol) of 10-O-propargylated ginkgolide
1
A (3’). H-NMR (600 MHz, DMSO-d
6) δ 8.82 (s, 1H), 8.16 (dd, J = 7.9, 1.5 Hz, 1H), 7.98 (td, J = 7.9, 1.5
Hz, 1H), 7.91 (dd, J = 8.2, 1.2 Hz, 1H), 7.79 (td, J = 7.7, 1.2 Hz, 1H), 6.41 (s, 1H), 6.16 (s, 1H), 5.41 (d, J =

Molecules 2019, 24, 2156
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1
1.9 Hz, 1H), 5.39–5.35 (m, 2H), 5.26 (s, 1H), 4.97–4.87 (m, 2H), 4.82 (t, J = 7.8 Hz, 1H), 2.95 (q, J = 7.1
13
Hz, 1H), 2.79–2.72 (m, 1H), 1.40 (s, 3H), 1.13 (d, J = 7.2 Hz, 3H), 1.04 (s, 9H). C-NMR (150 MHz,
DMSO-d
6) δ 174.85, 171.03, 168.75, 142.36, 133.25, 133.10, 128.73, 128.69, 124.10, 123.44, 110.75, 108.04,
1
8
08.01, 98.77, 95.53, 85.83, 84.40, 83.30, 73.77, 66.57, 64.74, 61.33, 47.05, 39.68, 34.68, 34.37, 31.51(3C),
+
.07. HRMS (ESI): m/z calcd for C30
H
30N
4O9
[M + H] : 591.2093, found 591.2062.
1
0-O-(1-Benzyl -1H-1,2,3-triazole) ginkgolide A (5’ff). Following the described procedure, 39.4 mg (68%)
of compound 5’ff were obtained from 44.6 mg (0.1 mmol) of 10-O-propargylated ginkgolide A (3’).
1
H-NMR (600 MHz, DMSO-d ) δ 8.25 (s, 1H), 7.38 (dd, J = 8.0, 6.4 Hz, 2H), 7.34–7.22 (m, 3H), 6.40 (s,
6
1
4
H), 6.12 (s, 1H), 5.61 (d, J = 6.9 Hz, 2H), 5.24 (d, J = 11.6 Hz, 1H), 5.16 (s, 1H), 4.92 (d, J = 4.0 Hz, 1H),
.82 (t, J = 7.8 Hz, 1H), 4.76 (d, J = 11.6 Hz, 1H), 4.03 (q, J = 7.1 Hz, 1H), 2.94 (d, J = 7.2 Hz, 1H), 2.65
(dd, J = 15.1 Hz, 7.2 Hz, 1H), 2.50 (p, J = 1.8 Hz, 3H), 2.05–1.99 (m, 1H), 1.99 (s, 1H), 1.90 (d, J = 4.4 Hz,
1
7
1
6
+
H), 1.84 (dd, J = 15.1, 8.4 Hz, 1H), 1.70 (dd, J = 14.1, 4.7 Hz, 1H), 1.17 (t, J = 7.1 Hz, 1H), 1.12 (dd, J =
1
3
.1, 4.0 Hz, 3H), 0.98 (d, J = 3.6 Hz, 9H). C-NMR (150 MHz, DMSO-d
6) δ 177.20, 173.13, 171.32, 136.27,
29.28(2C), 128.74, 128.39, 124.82, 110.16, 110.03, 101.11, 88.10, 86.53, 85.77, 75.61, 68.76, 66.93, 63.50,
3.40, 53.55, 53.35, 49.15, 40.86, 36.82, 32.04, 29.02(3C), 8.71. HRMS (ESI): m/z calcd for C30
H] : 580.2297, found 580.2267.
H33N
3
O [M
9
+
10-O-(((Anthracen-2-yloxy)methyl)-1H-1,2,3-triazole) ginkgolide A (5’gg). Following the described
procedure, 36.9 mg (61%) of compound 5’gg were obtained from 44.6 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide A (3’). H-NMR (600 MHz, DMSO-d
6) δ 8.29 (s, 1H), 7.92 (dd, J = 7.7, 1.4 Hz,
1
2
H), 7.82–7.69 (m, 1H), 7.57 (td, J = 7.7, 1.2 Hz, 1H), 7.44–7.26 (m, 1H), 6.40 (s, 1H), 6.13 (s, 1H), 5.83 (s,
H), 5.27 (d, J = 11.8 Hz, 1H), 5.18 (s, 1H), 4.90 (d, J = 4.0 Hz, 1H), 4.83 (dd, J = 8.2 Hz, 7.3 Hz, 1H), 4.78
(d, J = 11.7 Hz, 1H), 4.03 (q, J = 7.1 Hz, 19H), 2.95 (q, J = 7.2 Hz, 1H), 2.66 (dd, J = 15.2 Hz, 7.2 Hz, 1H),
2
.51 (p, J = 1.8 Hz, 4H), 1.90–1.82 (m, 2H), 1.72 (dd, J = 14.1 Hz, 4.7 Hz, 2H), 1.40 (s, 3H), 1.13 (d, J = 7.2
13
Hz, 3H), 0.99 (d, J = 5.3 Hz, 9H). C-NMR (150 MHz, DMSO-d
6) δ 176.93, 173.14, 170.81, 143.66, 139.26,
1
6
C
34.29, 133.85, 129.91, 129.68, 125.44, 117.45, 111.68, 110.09, 100.82, 87.90, 86.50, 85.33, 75.74, 68.63,
6.81, 63.47, 60.22, 51.47, 49.03, 40.89, 36.40, 32.14, 29.10(3C), 8.56. HRMS (ESI): m/z calcd for
+
31H32N4O
9
[M + H] : 605.2249, found 605.2219.
1
0-O-(1-Phenyl-1H-1,2,3-triazole) ginkgolide C (5’’a). Following the described procedure, 31.1 mg (52%)
of compound 5’’a were obtained from 47.8 mg (0.1 mmol) of 10-O-propargylated ginkgolide C (3’’).
1
H-NMR (600 MHz, DMSO-d ) δ 8.83 (s, 1H), 7.88 (dt, J = 7.9, 1.1 Hz, 2H), 7.63 (dd, J = 8.8, 7.2 Hz, 3H),
6
7
1
2
1
d
7
.53 (t, J = 7.4 Hz, 1H), 6.48 (s, 1H), 6.23 (s, 1H), 5.64 (t, J = 5.3 Hz, 2H), 5.46 (d, J = 12.2 Hz, 1H), 5.32 (s,
H), 4.99 (d, J = 4.2 Hz, 2H), 4.63 (d, J = 7.0 Hz, 1H), 4.32 (s, 1H), 4.17 (dd, J = 7.0 Hz, 4.6 Hz, 1H), 2.98–
.78 (m, 1H), 1.99 (s, 1H), 1.57 (d, J = 12.5 Hz, 1H), 1.43–1.35 (m, 2H), 1.32–1.27 (m, 1H), 1.24 (s, 2H),
13
.17 (t, J = 7.1 Hz, 1H), 1.13 (d, J = 7.1 Hz, 4H), 1.10 (s, 3H), 1.07 (s, 9H). C-NMR (150 MHz, DMSO-
) δ 176.79, 172.94, 170.86, 162.28, 144.14, 136.89, 130.50, 122.14, 120.73, 110.04, 99.08, 93.14, 82.93,
6
5.47, 74.09, 67.05, 64.03, 63.52, 60.84, 49.35, 42.03, 35.12, 32.08, 19.09(3C), 14.32, 8.34. HRMS (ESI): m/z
+
calcd for C29
H31N3O
11 [M + H] : 598.2039, found 598.2003.
1
0-O-(1-(2-Methylphenyl)-1H-1,2,3-triazole) ginkgolide C (5’’n). Following the described procedure, 28.7
mg (47%) of compound 5’’n were obtained from 47.8 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide C (3’’). H-NMR (600 MHz, DMSO-d
6) δ 8.47 (s, 1H), 7.50 (d, J = 2.2 Hz, 2H), 7.44 (d, J = 1.4
Hz, 2H), 6.48 (s, 1H), 6.23 (s, 1H), 5.68 (d, J = 4.7 Hz, 1H), 5.66 (dd, J = 6.2 Hz, 2.5 Hz, 1H), 5.49–5.43
m, 1H), 5.32 (s, 1H), 5.02–5.00 (m, 2H), 5.00–4.96 (m, 1H), 4.65–4.61 (m, 1H), 4.17 (dd, J = 7.0 Hz, 4.7
Hz, 1H), 2.86 (d, J = 7.1 Hz, 1H), 2.16 (s, 3H), 1.13 (d, J = 7.1 Hz, 4H), 1.10 (d, J = 3.7 Hz, 6H), 1.08 (s,
(
9
1
4
6
H). 13C-NMR (150 MHz, DMSO-d
) δ 176.81, 172.95, 170.89, 143.24, 136.51, 133.52, 131.93, 130.49,
6
27.57, 126.41, 125.27, 110.03, 99.05, 93.12, 82.92, 79.36, 75.41, 74.07, 69.35, 67.06, 64.05, 60.27, 49.38,
+
2.03, 32.10, 21.23(3C), 17.86, 8.34. HRMS (ESI): m/z calcd for C30
H33N3O
11 [M + H] : 612.2195, found
12.2157.

Molecules 2019, 24, 2156
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1
0-O-(1-(2-Cyanophenyl) -1H-1,2,3-triazole) ginkgolide C (5’’p). Following the described procedure, 24.3
mg (39%) of compound 5’’p were obtained from 47.8 mg (0.1 mmol) of 10-O-propargylated
1
ginkgolide C (3’’). H-NMR (600 MHz, DMSO-d
6) δ 8.78 (s, 1H), 8.17 (dd, J = 7.7, 1.4 Hz, 1H), 7.99 (td,
J = 7.8 Hz, 1.5 Hz, 1H), 7.88 (dd, J = 8.2 Hz, 1.1 Hz, 1H), 7.79 (td, J = 7.7 Hz, 1.1 Hz, 1H), 6.48 (s, 1H),
.23 (s, 1H), 5.64 (d, J = 6.1 Hz, 1H), 5.60 (d, J = 4.7 Hz, 1H), 5.49 (d, J = 12.4 Hz, 1H), 5.32 (s, 1H), 5.03
d, J = 12.4 Hz, 1H), 5.01 (d, J = 4.2 Hz, 1H), 4.63 (d, J = 7.0 Hz, 1H), 4.17 (dd, J = 7.0 Hz, 4.7 Hz, 1H),
6
(
3
7
1
4
6
.97 (ddd, J = 12.5 Hz, 6.1 Hz, 4.2 Hz, 1H), 2.86 (q, J = 7.1 Hz, 1H), 1.57 (d, J = 12.5 Hz, 1H), 1.13 (d, J =
13
.1 Hz, 3H), 1.08 (s, 9H). C-NMR (150 MHz, DMSO-d ) δ 176.78, 172.90, 170.87, 143.98, 135.47, 126.10,
6
24.92, 116.26, 110.05, 107.36, 99.11, 93.18, 82.95, 79.34, 75.46, 74.18, 74.07, 67.04, 64.02, 63.40, 60.25,
+
9.37, 42.03, 32.10, 27.01, 22.55, 21.24(3C), 8.35. HRMS (ESI): m/z calcd for C30
H
30N
4
O
11 [M + H] :
23.1991, found 623.1956.
1
0-O-(1-Benzyl-1H-1,2,3-triazole) ginkgolide C (5’’ff). Following the described procedure, 26.9 mg (44%)
of compound 5’’ff were obtained from 47.8 mg (0.1 mmol) of 10-O-propargylated ginkgolide C (3’’).
1
H-NMR (600 MHz, DMSO-d ) δ 8.19 (s, 1H), 7.40–7.37 (m, 2H), 7.35–7.32 (m, 3H), 6.46 (s, 1H), 6.20 (s,
6
1
1
H), 5.73 (s, 1H), 5.62 (s, 3H), 5.35 (d, J = 12.2 Hz, 1H), 5.25 (s, 1H), 4.97 (d, J = 4.2 Hz, 1H), 4.87 (d, J =
2.2 Hz, 1H), 4.61 (d, J = 7.2 Hz, 1H), 4.13 (d, J = 5.7 Hz, 1H), 3.90 (d, J = 11.4 Hz, 1H), 2.84 (q, J = 7.1
Hz, 1H), 1.55 (dd, J = 12.5 Hz, 5.2 Hz, 1H), 1.17 (t, J = 7.1 Hz, 3H), 1.12 (d, J = 7.1 Hz, 4H), 1.10–1.09 (m,
2
1
4
H), 1.03 (s, 9H). 13C-NMR (150 MHz, DMSO-d
) δ 176.81, 172.93, 170.87, 143.32, 136.15, 129.29(2C),
6
28.75, 128.56, 123.60, 110.01, 98.96, 93.02, 82.83, 79.33, 75.34, 74.01, 67.04, 64.00, 63.56, 60.27, 53.51,
+
9.30, 42.03, 32.04, 29.07, 21.23(3C), 8.27. HRMS (ESI): m/z calcd for C30
H33N4O
11 [M + H] : 612.2195,
found 612.2156.
10-O-(((Anthracen-2-yloxy)methyl)-1H-1,2,3-triazole) ginkgolide C (5’’gg). Following the described
procedure, 32.5 mg (51%) of compound 5’’gg were obtained from 47.8 mg (0.1 mmol) of 10-O-
1
propargylated ginkgolide C (3’’). H-NMR (600 MHz, DMSO-d
6) δ 8.25 (s, 1H), 7.93 (dd, J = 7.7, 1.4
Hz, 1H), 7.74 (td, J = 7.7 Hz, 1.4 Hz, 1H), 7.58 (td, J = 7.7 Hz, 1.2 Hz, 1H), 7.40 (dd, J = 7.8 Hz, 1.1 Hz,
1
1
H), 6.46 (s, 1H), 6.20 (s, 1H), 5.84 (s, 2H), 5.70 (d, J = 4.8 Hz, 1H), 5.62 (d, J = 6.1 Hz, 1H), 5.37 (d, J =
2.2 Hz, 1H), 5.26 (s, 1H), 4.98 (d, J = 4.2 Hz, 1H), 4.90 (d, J = 12.1 Hz, 1H), 4.61 (d, J = 7.0 Hz, 1H), 4.13
(
dd, J = 7.1 Hz, 4.4 Hz, 1H), 3.90 (dt, J = 12.4 Hz, 4.7 Hz, 1H), 2.84 (q, J = 7.0 Hz, 1H), 2.50 (s, 3H), 1.55
1
3
(d, J = 12.5 Hz, 1H), 1.18 (t, J = 7.1 Hz, 3H), 1.12 (d, J = 7.2 Hz, 3H), 1.04 (s, 9H). C NMR (150 MHz,
DMSO-d
6) δ 176.83, 172.94, 170.92, 143.37, 138.90, 134.36, 133.88, 130.11, 129.85, 124.19, 117.47, 111.82,
1
10.02, 98.99, 82.84, 79.33, 75.38, 74.15, 74.01, 67.05, 64.01, 63.53, 60.27, 51.69, 49.33, 42.03, 32.04, 21.22
+
(3C), 8.28. HRMS (ESI): m/z calcd for C31
H
32N4O
11 [M + H] : 637.2148, found 637.2117
3
.2. Antiplatelet Aggregation Activity Assay
The in vitro antiplatelet aggregation activity of the newly synthesized 10-substituted 1,2,3-
triazole-ginkgolide derivatives was tested by the method of Born [26]. Blood samples (2 mL) from
male New Zealand rabbits (2-2.5 kg body weight) were drawn into vacutainer tubes containing 200
μL of 3.2% sodium citrate. Platelet-rich plasma (PRP) was prepared by centrifuging the blood at 250
g for 10 min at 4 °C. The PRP was diluted with platelet-poor plasma obtained by further centrifuging
at 3000g for 10min. The remaining blood was further centrifuged at 1600 × g for 5 min to obtain
platelet-poor plasma (PPP) as control group. Platelet aggregation was induced by PAF (10 nM) after
incubating platelets with different concentrations of samples, and the maximum rate of platelet
aggregation (RPA%) within 5 min was measured with a Helena Platelet aggregometer instrument
[27]. The inhibition ratio was calculated according to the following formula:
Inhibition ratio (%) = (1−(RPA% of test group) / (RPA% of control group)) × 100%
In primary screening, the activities were expressed directly as inhibition ratio at 50 nM
concentration. The activity of the most active ginkgolide-1,2,3-triazole derivatives was further
expressed as the IC50 value (the concentration required to inhibit platelet aggregatory response by
50%). The values shown in the tables were calculated by linear regression from a single experimental

Molecules 2019, 24, 2156
19 of 21
curve with no less than four data points, each point being the mean of the percentage inhibition at a
given concentration obtained from three independent experiments.
3
.3. LDH Assay
3
.3.1. Preparation of H9c2 Cells
H9c2 cardio myoblast cells were grown in DMEM supplemented with 10% FBS, 100 U/mL
penicillin-streptomycin. Cells were cultured at 37 °C with 5% CO
they reached 70-80% confluence [28]. Then the cells were seeded at 1×10 cells per well in 96-well
2
. The cells were subcultured when
4
plate and incubated overnight. Then the cells were exposed to ginkgolide-1,2,3-triazole derivatives
(1 μM and 10 μM).
3
.3.2. Preparation of Washed Platelets
Rat blood was collected in 3.8% sodium citrate vacuum anticoagulant tubes and centrifuged at
00 g for 15 min to obtain platelet-rich plasma (PRP). The PRP was centrifuged at 1000 g for 10 min
1
at 37 °C. Then the platelet pellets were suspended in Tyrode’s solution (pH 7.4). The washed platelets
8
8
were adjusted to 3.6 × 10 platelets/mL. Washed platelets (3.6 × 10 cells/mL) were pre-incubated with
ginkgolide-1,2,3-triazole derivatives (1μM and 10 μM) or 0.1% DMSO for 20 min at 37 °C, then
centrifuged at 1700 g, 10 min and the supernatant collected [29].
3
.3.3. Measurement of Lactate Dehydrogenase (LDH)
The assays to measure of LDH release were conducted in 96-well plates according to the
manufacturer’s protocol. The LDH levels were measured at 490 nm using a microplate reader
Thermo Fisher Scientific, Waltham, MA, USA). Cell cytotoxicity was also detected by the LDH
activity assay kit. Cells incubated with 0.1% dimethyl sulfoxide (DMSO) served as the control group
28,29].
(
[
4
. Conclusions
In summary, a series of ginkgolide-1,2,3-triazole conjugates were synthesized through a
copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction of the corresponding 10-O-
propargylated ginkgolides with benzyl, phenyl and heterocyclic azides. Five of them (compounds 5a,
5
p, 5ff, 5gg and 5’a) displayed promising antiplatelet aggregation activities with IC50 values ranging
from 5-21 nM. Compounds 5ff and 5gg, having a benzyl group attached at the triazole nucleus were
the best among the series of compounds. The most active compounds may be regarded as safe
towards normal cells and platelets at therapeutic concentrations.
Author Contributions: Conceptualization, Q.-W.Z.; Methodology, J.C., L.-A.H. and G.C.; Investigation, J.C.,
L.-A.H. and W.S.; Writing-Review & Editing, J.C. and Q.-W.Z.; Project Administration, Q.-W.Z. and X.Z.;
Funding Acquisition, Q.-W.Z.
Funding: This research was funded by Macao Science and Technology Development [FDCT/113/2013/A3] and
Research Committee of the University of Macau (MYRG2016-00046-ICMS-QRCM).
Acknowledgments: We gratefully acknowledge the academic and technical assistance from Yu Chang.
Conflicts of Interest: The authors declare no conflict of interest.
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Sample Availability: Samples of the compounds 5a–5gg, 5’a-5’gg, 5’’a–5’’gg are available from the authors.
©
2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
CC BY) license (http://creativecommons.org/licenses/by/4.0/).
(