1,2,3-Triazole pharmacophore-based benzofused nitrogen/sulfur heterocycles with potential anti-Moraxella catarrhalis activity

Article abstract of DOI:10.1016/j.bmc.2015.10.042

Versatile 1,2,3-triazole pharmacophore-based benzofused heterocycles containing halogen-substituted aromatic (9-17 and 25-28), 7-substituted coumarin (18-23 and 29-30) or penciclovir-like subunit (31a,b-38a) were designed and synthesized to evaluate their

Full text of DOI:10.1016/j.bmc.2015.10.042

Bioorganic & Medicinal Chemistry xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
1,2,3-Triazole pharmacophore-based benzofused nitrogen/sulfur
heterocycles with potential anti-Moraxella catarrhalis activity
a
b
b
b
ˇ ´ a
´
ˇ ´
´
´
´
ˇ
Silvija Maracic , Tatjana Gazivoda Kraljevic , Hana Cipcic Paljetak , Mihaela Peric , Mario Matijašic ,
b
c
a,
⇑
´
Donatella Verbanac , Mario Cetina , Silvana Raic-Malic
a
´
Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 20, HR-10000 Zagreb, Croatia
b Department for Intercellular Communication, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, Šalata 2, HR-10000 Zagreb, Croatia
c Department of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz baruna Filipovic´a 28a, HR-10000 Zagreb, Croatia
a r t i c l e i n f o
a b s t r a c t
Article history:
Versatile 1,2,3-triazole pharmacophore-based benzofused heterocycles containing halogen-substituted
aromatic (9–17 and 25–28), 7-substituted coumarin (18–23 and 29–30) or penciclovir-like subunit
(31a,b–38a) were designed and synthesized to evaluate their antibacterial activities against selected
Gram-positive and Gram-negative bacteria. Hybridization approach using environmentally friendly Cu
(I)-catalyzed click reaction under microwave irradiation was adopted in the synthesis of regioselective
1,4-disubstituted 1,2,3-triazole tethered heterocycles (9–23 and 25–30), while post-N-alkylation of
NH-1,2,3-triazoles afforded both 2,4- (31a–38a) and 1,4-disubstituted (31b–33b, 35b–37b) 1,2,3-triazole
regioisomers. The compounds 18–23 and 25–30 revealed fluorescence in the violet region of the visible
spectrum with a strong influence of phenyl spacer in 25–30 on both wavelength and emission intensity.
Fusion of selected subunits led to new hybrid architecture, benzothiazole–1,2,3-triazole–coumarin 29
that demonstrated extremely narrow spectrum activity towards fastidious Gram-negative bacteria
Received 15 September 2015
Revised 28 October 2015
Accepted 29 October 2015
Available online xxxx
Keywords:
1,2,3-Triazole
Coumarin
Hybridization approach
Fluorescence
Antibacterial activity
Moraxella catarrhalis
Moraxella catarrhalis. Selected hybrid showed the potency against Moraxella catarrhalis (MIC 6 0.25 lg/
mL) comparable to that of reference antibiotic azithromycin, which suggested that further investigations
are necessary to optimize this potential hit compound as a new anti-Moraxella catarrhalis agent.
Ó 2015 Elsevier Ltd. All rights reserved.
1. Introduction
research aimed to find vaccines for prevention or selective antibi-
otics for the treatment of respiratory tract infections.4 To date,
Moraxella catarrhalis is a human-restricted pathogen, that is,
responsible for respiratory tract infections such as childhood otitis
media (OM) and exacerbations of chronic obstructive pulmonary
disease (COPD) in adults.1 Long considered to be a harmless inhab-
itant of the upper respiratory tract, this bacterium has now firmly
been established to be an emerging unencapsulated Gram-nega-
tive mucosal pathogen. It is the third most common cause of OM
after Haemophilus influenzae and Streptococcus pneumoniae respon-
sible for up to 20% of the cases and is the second most common
cause of exacerbations of COPD after H. influenzae.2 It was found
that M. catarrhalis induces inflammatory response of bronchial
epithelial cells via mitogen-activated protein (MAP) kinases, tran-
most therapeutic guidelines recommend antibiotics for treatment
of OM cases.5
However, excessive or improper uses of antibiotics led to the
development of antibacterial resistance worldwide during the last
few decades,4 suggesting the incidence of these infections may
continue to rise. Thus, new active classes of antibiotics are urgently
needed for the most common community-acquired respiratory
pathogens with emerging antimicrobial resistance. Several hetero-
cyclic moieties containing nitrogen, sulfur and/or oxygen hetero-
atoms have been explored for the development of new generation
antimicrobial agents.6 Among them, the 1,2,3-triazole scaffold is
considered a lead structure for the synthesis of more efficacious
and broad spectrum antimicrobial agents.7–10 The discovery that
copper(I)-catalyzed reactions between terminal alkynes and azides
(CuAAC) forms efficiently and regioselectively 1,4-disubstituted
1,2,3-triazoles has increased the application of click chemistry in
drug discovery, particularly in lead identification and lead opti-
mization processes.11 The 1,2,3-triazole unit may be considered
as a bioisostere of the amide group because these moieties have
scription factor NF-jB and histone deacetylase activity reduction,
which is particularly strongly activated in epithelial cells of COPD.3
The fact that M. catarrhalis was not accepted as an important
human pathogen until recently has contributed to the limited
⇑
Corresponding author. Tel.: +385 1 4597 213; fax: +385 1 4597 224.
E-mail address: sraic@fkit.hr (S. Raic´-Malic´).
http://dx.doi.org/10.1016/j.bmc.2015.10.042
0968-0896/Ó 2015 Elsevier Ltd. All rights reserved.
ˇ ´
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
2
O
H-bond acceptor capacity, distance between substituents and
dipolar properties similar to the peptide bond.12 It was also estab-
lished that 1,2,3-triazole cores interact strongly with biological tar-
gets through hydrogen bonding to nitrogen atoms and their large
dipole moments.13
O
H3CO
O
N
H
O
S
N
HN
S
NH
S
Cl
O
N
Furthermore, benzimidazole core is an important source of
bioactivity in the area of drug discovery because of its varied bio-
logical activities, including antimicrobial activity.14–18 Thus, among
the series of [(1,2,4)-triazolyl]phenyl substituted 4,6-difluorobenz-
imidazoles I,16 analogs with electronegative substituents emerged
as promising antimicrobials, while 2-thiobenzimidazole with
[(1,2,4-triazolyl)ethylthio]phenyl moiety II19 exhibited antibacte-
rial properties that were selective for Helicobacter pylori (Fig. 1).
Moreover, clubbed 1,2,3-triazoles with fluorine benzimidazole
derivatives III20 showed pronounced antitubercular activities
(Fig. 1). Some 2-aryl-1-hydroxy-benzimidazoles were identified
as effective broad-spectrum small-molecule inhibitors of proteins
within the AraC family of bacterial transcription factors, which
control virulence by controlling antibiotic and oxidative stress
resistance, expression of type III secretion, toxin production, and
other processes that are important during infection.21,22
IV
V
N
R
N
N
N
O
N
S
O
S
S
N
N
NH
N
N
N
R
N
N
R
R = Cl, Br, F, CN, OCH3
R = 2,4-diFPh
N
VI
VII
S
Cl
S
N
N
N
N
VIII
It was revealed that benzothiazoles possess significant potential
as new antimicrobial and antitubercular agent.23 After consistent
efforts, a new class of benzothiazole derivatives bearing the amide
moiety, potent against pathogenic bacterial species, has emerged
and resulted with a new lead molecules comprising 2-arylbenzoth-
iazole amide (IV),24 benzothiazole-thiophene conjugate (TCA-1)
linkaged via an amide bond (V)25 and benzothiazole–acetamide
system (VI),26 which played an essential role to furnish promising
antimicrobial activities (Fig. 2). Compound IV displayed potent
activity against clinically relevant pathogens Escherichia coli and
Staphylococcus aureus along with a membrane perturbing mode
of action, and an intracellular mode of action due to binding with
DNA, while V,25 as antituberculosis agent, inhibited
Figure 2. Representatives of benzothiazole amide derivatives IV–VI and clubbed
benzothiazole with 1,2,3-triazole VII and VIII as potent antimicrobial and antitu-
berculosis agents.
cumarin derivatives, compound containing piperazine moiety IX8
showed noticeable activity against Pseudomonas aeruginosa
(Fig. 3). Furthermore, bis-1,2,4-triazole coumarin derivative X29
containing a butylene linker displayed much stronger antimicrobial
efficacy than corresponding mono-triazole derivative. Moreover,
bis-triazole coumarin derivative with triazole alcohol fragment in
X30 gave better anti-MRSA (methicillin-resistant Staphylococcus
aureus) activity than mono-triazole and standard drug (Fig. 3).
Keeping into consideration the tremendous biological potency
of aforementioned structural classes, particularly their antimicro-
bial activity, and in continuation of our recent effort toward the
synthesis of 1,2,3-triazole-appended acyclonucleosides31–33 herein
we designed and synthesized novel benzofused nitrogen/sulfur
heterocycles and 1,2,3-triazoles conjugates for their evaluation as
antibacterial agents.
Thus, the designed scaffold (Fig. 4) consists of 1,2,3-triazole as a
central backbone, benzofused heterocycle attached to the triazole
unit to gain target pharmacophoric properties and aliphatic or
aromatic group linked to the 4-position of the triazole core for
lipophilicity. Herein, for the first time, selective anti-Moraxella
catarrhalis activity of representatives of 1,2,3-triazole based
bis-heterocycles is reported.
decaprenylphosphoryl-b-D-ribofuranose oxidoreductase, DprE1,
enzyme involved in cell wall biosynthesis. Furthermore, recent
studies demonstrated the utility of benzothiazol-2-yl-bis-1,2,3-tri-
azolyl amines as antimicrobial agents, among which compound
VII27 containing 2,4-difluorophenyl ring showed excellent potency
against all evaluated Gram-positive and Gram-negative bacterial
strains which was two-fold more active as compared to standard
drug ciprofloxacin. Sulfur rich benzothiazole and 1,2,3-triazole
conjugates VIII6 exhibited antitubercular activity revealing that
these compounds may act as DprE1 inhibitors (Fig. 2).
The potential of coumarins of natural and synthetic origin as
novel therapeutic agents is well reported.28 Among the triazolyl
N
F
N
2. Results
N
S
N
N
H3C
N
2.1. Chemistry
N
N
N
R
F
S
R = -CH2(3-FC6H5),
-CH2(3-FC6H5),
-CH2(4-FC6H5)
N
H
A focused library of 20 compounds from the benzimidazole and
indole (9–23), and benzothiazole (25–30) series containing
I
II
F
N
O
N
N
CH3
O
O
R
O
N
R
O
O
N
N
R3
N
N
N
N
N
N
N
R2
R1
O
N
N
O
R1, R2, R3 = H, F
n
R = -(CH2)2-
-CH-
N
n = 6
IX
X
III
OH
Figure 1. Representatives of benzimidazoles containing triazole moiety I–III with
Figure 3. Representatives of coumarins containing triazole moiety IX and X with
potential antimicrobial and antituberculosis activities.
potential antimicrobial activities.
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
R5
X
N
H3C
N-hetrocycle
S
N
core
R2
N
NH
1,2,3-triazole
backbone
spacer
N
R2 = H, CH3
R5 = H, I, F
n = 0, 1
N
N
N
N
n
n
n = 0, 1
Ar
aromatic or
Ar/Al
aliphatic unit
9
−
23, 31a,b
−
38a
25−30
lipophilicity control
Figure 4. Benzofused nitrogen/sulfur heterocycle–1,2,3-triazole hybrids 9–23 and 25–38a.
aromatic 4-substituted 1,2,3-triazole unit and 14 compounds from
benzimidazole and indole (31a,b–38a) series with aliphatic side
chain have been synthesized. The most recent molecular
hybridization approach based on the combination of pharma-
cophoric moieties of different compounds was used to produce a
new hybrid molecules with improved biological properties.34 Here,
a triazole unit and a benzofused heterocycles consisting of nitro-
gen/sulfur heteroatoms were hybridized in one molecular platform
to generate compounds with selective antimicrobial activities. The
method adopted for the synthesis of 1,4-disubstituted-1,2,3-tria-
zole was based on a copper(I)-catalyzed Huisgen 1,3-dipolar
cycloaddition reaction of a terminal alkyne with an azide. N-
Propargylated derivatives of corresponding heterocycles (benzimi-
dazole, 2-methylbenzimidazole, 5-iodoindole, 5-fluoroindole)
were prepared with propargyl bromide in the presence of K2CO3,
as a base, to achieve alkynyl derivatives 1–4.
N-Unsubstituted 1,2,3-triazoles 5–8 were synthesized in the
reaction of 1–4 with azidotrimethyl silane (TMSN3) in the presence
of CuI, as a catalyst. The various halogen-substituted aromatic
azide precursors required for the preparation of 1,2,3-triazole
based bis-heterocycles 9–18 and 25–28 were synthesized from
the corresponding arylamines using standard azidation method.35
1,2,3-Triazole-benzofused heterocycle conjugates 9–18 and
25–28 were obtained by copper(I)-catalyzed click chemistry under
microwave irradiation in a very good yield (in the range of 74–85%)
(Schemes 1 and 2). Reactions of 5-iodoindole with halogen-
substituted aromatic azide did not afford target 5-iodoindole–
1,2,3-triazole conjugates.
R5
R5
R5
X
N
X
X
N
(ii)
(i)
R2
R2
R2
N
N
H
R1
N
N
1
−
4
5−
23
Compd.
R1
-
-
-
-
H
H
H
H
R2
R5
H
H
I
F
H
H
I
X
N
N
CH
CH
N
N
CH
CH
Yield (%) ClogPa
1
2
3
4
5
6
7
8
H
84
76
67
33
61
31
54
65
1.71
1.83
3.45
2.67
1.21
1.34
2.95
2.17
CH3
H
H
H
CH3
H
H
F
Cl
9
H
CH3
H
H
H
H
H
H
H
N
N
N
N
N
N
89
84
84
74
76
84
3.60
3.72
3.87
3.99
3.14
3.26
Cl
CF3
CF3
F
10
11
12
13
14
CH3
H
F
CH3
15
16
17
H
CH3
H
H
H
H
N
N
N
85
82
77
3.14
3.26
4.20
Encouraged by recent findings that introduction of coumarin
ring improved antimicrobial potencies,29 we synthesized 1,2,3-tri-
azole-tethered benzofused heterocycle–coumarin chimeras 18–23
and 29–30 from prepared coumarin azides and terminal alkynes
F
F
Cl
(Schemes
1 and 2). Azidomethyl coumarin derivatives were
Cl
O
O
OH
obtained in the reaction of sodium azide with 4-chloromethyl-7-
methylcoumarin and 4-chloromethyl-7-hydroxycoumarin which
were synthesized in the reaction of m-hydroxyphenol and m-cresol
with ethyl 4-chloroacetoacetate under Pechmann cyclization con-
dition using sulfuric acid to give 7-hydroxy and 7-methylcoumarin
derivatives, respectively.36,37 Syntheses of benzothiazole–1,2,3-tri-
azole hybrids 25–30 were carried out involving reaction of corre-
sponding halogen-substituted aromatic and coumarine azides
18
19
20
21
22
23
H
H
H
H
H
H
I
N
N
76
67
83
81
85
78
2.35
3.17
2.35
3.29
4.09
4.91
O
O
CH3
O
O
O
O
OH
CH3
CH3
H
N
CH3
N
with
2-(4-(prop-2-ynyl)aminophenyl)-6-methylbenzothiazole
(24), that was prepared from 2-aminobenzothiazole and propargyl
bromide as outlined in Scheme 2.
O
O
OH
CH
CH
Enclosure of penciclovir-like side chain was performed by
N-alkylation of NH-1,2,3-triazoles (5–8) with 2-acetoxymethyl-4-
iodobutyl acetate under basic condition, in the presence of
K2CO3, to give mixture of N-2- and N-1-alkylated regioisomers in
which N-2-alkylated isomers prevailed (ratio for 31a/31b,
32a/32b and 33a/33b amounted 3/1, 4/1 and 2/1, respectively)
(Scheme 3). N-Alkylation of NH-1,2,3-triazole–5-fluoroindole
hybrid 8 yielded only N-2-alkylated isomer 34a without isolation
of its N-1-alkylated analog. The final deprotection of two acetyl
O
O
CH3
H
I
aValues of n-octanol/water partition coefficients logP were calculated using ChemAxon
algorithm (MarvinView Ver. 6.2.2.).
Scheme 1. Reagents and conditions: (i) propargyl bromide, K2CO3, DMF, Ar
atmosphere, 60 °C, 24 h; (ii) (a) TMSN3, CuI, DMF/CH3OH = 9:1, Ar, 100 °C, 8 h or
(b) corresponding azide, Cu, 1 M CuSO4 solution, tert-butanol/H2O = 1:1, MW
300 W, 80 °C, 30 min.
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S
N
R'
R'
H3C
H3C
S
N
(i)
R5
NH
R5
R5
NH2
R'
X
X
N
X
N
R'
R2
R2
N
R2
N
(i)
N
+
24
N
N
N
N
N
N
1
H
2
N
(ii)
b
a
5−8
H3C
31 34a
31 33b
−
−
S
N
ii
ii
35−38a
35−37b
NH
R1
N
Compd.
R2
R5
X
R'
Yield (%) ClogPa
N
N
25−30
Yield
31a
31b
32a
32b
33a
33b
34a
35a
35b
36a
36b
37a
37b
38a
OAc
OAc
OAc
OAc
OAc
OAc
OAc
OH
80
25
84
19
26
13
66
61
43
84
78
45
53
26
0.78
1.08
0.9
R1
ClogPa
H
H
H
H
H
H
I
N
N
Compd.
(%)
F
25
26
5.78
74
CH3
CH3
H
N
F
5.78
83
1.20
2.52
2.82
1.74
-0.10
0.19
0.02
0.32
1.64
1.93
0.85
N
Cl
27
28
6.84
6.24
CH
CH
CH
N
84
80
Cl
Cl
H
I
H
F
H
H
H
H
I
O
O
O
O
OH
29
30
4.99
5.81
68
H
CH3
OH
H
N
71
CH3
CH3
H
N
OH
OH
OH
OH
OH
aValues of n-octanol/water partition coefficients logP were calculated using ChemAxon
algorithm (MarvinView Ver. 6.2.2.).
N
CH
CH
CH
Scheme 2. Reagents and conditions: (i) propargyl bromide, K2CO3, DMF, Ar
atmosphere, 60 °C, 24 h; (ii) corresponding azide, Cu, 1 M CuSO4 solution, tert-
butanol/H2O = 1:1, MW 300 W, 80 °C, 30 min.
H
I
H
F
groups in side chain using sodium methoxide gave target
1,2,3-triazole based bis-heterocycles 35a–38a and 35b–37b bear-
ing penciclovir-like side chain with free hydroxyl functionality.
aValues of n-octanol/water partition coefficients logP were calculated using ChemAxon
algorithm (MarvinView Ver. 6.2.2.).
Scheme 3. Reagents and conditions: (i) 2-acetoxymethyl-4-iodobutyl acetate,
K2CO3, DMF, rt, 24 h; (ii) 0.1 M NaOCH3/CH3OH, CH3OH, rt, 4 h.
2.2. X-ray crystal structure analysis
Compound 5 (Fig. 5), in which benzimidazole and 1,2,3-triazole
rings are linked via methylene spacer, crystallized in monoclinic
space group P 21/n as monohydrate. X-ray crystal structure analy-
sis shows that this compound exist in 1H-1,2,3-triazole tautomeric
form. Search of Cambridge Structural Database38 revealed that this
is the first example of N-unsubstituted 1H-1,2,3-triazole–benzimi-
dazole hybrid. Only one closely related structure published until
proliferating cells, cell imaging, and combinatorial synthesis of flu-
orescence dyes.40–42 In addition, coumarin derivatives have been
widely used in fluorescent molecular probes, electroluminescence,
light-harvesting molecular assemblies or photovoltaics because of
their favourable photophysical properties.43–47
Therefore, fluorescence properties of benzofused heterocycle–
1,2,3-triazole–coumarin 18–23 and benzothiazole–1,2,3-triazole
25–30 hybrids were further evaluated. Thus, methanolic solutions
of compounds 18–30 were characterized by means of electronic
absorption (UV/Vis) and fluorescence emission spectroscopy
(Table 1, Fig. 6). Compounds 18–23 exhibited absorption spectra
with maximum wavelengths in the range of 316–329 nm, while
compounds 25–30 showed maximum wavelengths of 343 nm or
347 nm. The phenyl spacer in benzothiazole–1,2,3-triazole hybrid
now39 is the 1-(b-
D-glucopyranosyl)-1,2,3-triazole that contains
1,5-disubstitued 1,2,3-triazole scaffold. Therefore, arrangement of
triazole ring single and double bonds in 5 and 1,5-disubstituted
1,2,3-triazole derivative is different. Namely, the N3–N2 bond in
5 is shorter than equivalent one in closely related structure for
ca. 0.04 Å and hence has double bond character, whereas the N1–
N2 bond is longer for ca. 0.02 Å and has more single bond charac-
ter. All other bond lengths in these two structures are very similar.
Benzimidazole ring in 5 is almost perpendicular with respect to the
1,2,3-triazole ring. The dihedral angle between the mean planes of
these two rings is 72.12(6)°.
Since this compound crystallized as hydrate the strongest inter-
actions are established between the molecule of 1,2,3-triazole
derivative and water molecule. These interactions, reinforced by
several weaker ones form three-dimensional network (for more
detailed description see Supplementary information).
25–30 extended the p-conjugated backbone in comparison to their
structural analogs 18–23 without phenyl subunit, thus causing red
shift of absorption wavelengths of 25–30 for ꢀ20 nm. All the com-
pounds displayed fluorescence in the violet region of the visible
spectrum with a variable emission intensity. The fluorescence
emission spectra of 19, 21–23 and 25–30 showed single emission
bands at 405 nm (for 19, 21–23) and ꢀ416 nm (for 25–30), while
emission spectra of compounds 18 and 20 showed dual bands at
405 and 469 nm. Observed dual emission bands for benzimida-
zole–1,2,3-triazole–7-hydroxycoumarin 18 and 2-methylbenzimi-
dazole–1,2,3-triazole–7-hydroxycoumarin 20 conjugates afford a
violet to blue emission.
2.3. UV–Vis absorption and fluorescence emission spectra
Fluorogenic click reaction has proved to be a versatile tool in the
application of protein labeling, labeling and detection of DNA in
Similar dual emission properties were found only for a few
coumarin fluorophores42 and were of particular interest for their
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
moiety did not cause any significant red or blue shifts in the emis-
sion wavelength.
Stokes shifts of 18–23 and 25–30 were dependent on the benzo-
fused heterocycle bonded to the C-4 of 1,2,3-triazole ring. Thus,
Stokes shifts for 2-phenylbenzothiazole derivatives 25–30 were
around 67-74 nm, while those of other benzofused heterocycle
derivatives 18–23 were higher amounting 76–89 nm. Interestingly,
2-arylbenzothiazole–1,2,3-triazole–7-hydroxycoumarin hybrid 29
displayed the highest emission intensity at 415 nm, that may be
attributed to two lone pairs of electrons of 7-hydroxyl substituent
at coumarin moiety. In contrast, its 7-methyl-substituted cou-
marin 30 showed hypochromic effect at the emission maximum
of 414 nm. The similar influence of the 7-hydroxy-substituted cou-
marin on the emission intensity was also found for benzofused
heterocycle–1,2,3-triazole–coumarin hybrids 18, 20 and 22 that
exhibited hypsochromic effect compared with the corresponding
7-methyl-substituted congeners 19, 21 and 23.
2.4. In vitro antibacterial evaluations and in silico analysis
The in vitro antibacterial activity of novel benzofused nitrogen/
sulfur heterocycle–1,2,3-triazole conjugates 5–38a was tested
against Gram-positive bacteria including Staphylococcus aureus
(ATCC 29213), Streptococcus pneumoniae (ATCC 49619), Streptococ-
cus pyogenes (ATCC 700294) and Gram-negative bacteria including
Escherichia coli (ATCC 25922), Moraxella catarrhalis (ATCC 23246)
and Haemophilus influenzae (ATCC 49247). The obtained results
were compared with known antibiotic azithromycin. To evaluate
Figure 5. (a)
A molecular structure of 5, with the atom-numbering scheme.
Displacement ellipsoids for non-hydrogen atoms are drawn at the 30% probability
level. Water molecule has been omitted for clarity. (b) Capped stick representation
of 5, showing N–Hꢃ ꢃ ꢃO, O–Hꢃ ꢃ ꢃN and C–Hꢃ ꢃ ꢃO intermolecular hydrogen bonds.
Water molecule is presented in ball and stick style.
18
19
(a)
20
21
22
23
25
26
27
28
29
30
0,35
0,30
0,25
0,20
0,15
0,10
0,05
0,00
-0,05
application such as white light electroluminiscence or luminescent
bioimaging.48,49 It is worth noting that the benzothiazole–1,2,3-tri-
azole hybrids 25–30 exhibited strong fluorescence intensity while
benzofused heterocycle–1,2,3-triazole–coumarin hybrids 18–23
showed significantly diminished fluorescence properties (Fig. 6)
indicating that a phenyl spacer in 25–30 was mainly responsible
for absorption of photons what is in agreement with earlier find-
ings.50 Among the benzofused heterocycle–1,2,3-triazole conju-
gates containing halogen-substituted aromatic subunit 25–28,
compounds 25 and 27 with 1-(p-fluorophenyl)- and 1-(2,5-dichlor-
ophenyl)-substituents, respectively, showed a higher emission
intensities. Furthermore, compounds 25–30 had red-shifted emis-
sion for ꢀ10 nm compared to benzofused heterocycle–1,2,3-tria-
zole–coumarin hybrids 18–23 without phenyl subunit. It can be
observed that various aryl substitutuent at N-1 of 1,2,3-triazole
300
350
400
λ / nm
(b)
18
400
300
200
100
0
19
20
21
22
23
25
26
27
28
29
30
Table 1
Photophysical data of compounds 18–23 and 25–30 in methanol
Compd
kmax
(nm)
emax
(Mꢂ1 cmꢂ1
kex
(nm)
kem
(nm)
Stoke shift
(nm)
)
18
329
0.38 ꢁ 104
329
405,
469
405
405,
469
405
405
405
417
417
414
415
415
414
76
19
20
316
326
0.82 ꢁ 104
0.33 ꢁ 104
316
326
89
79
21
22
23
25
26
27
28
29
30
317
326
317
347
343
347
343
343
343
0.66 ꢁ 104
0.07 ꢁ 104
0.71 ꢁ 104
1.73 ꢁ 104
0.82 ꢁ 104
1.32 ꢁ 104
0.61 ꢁ 104
0.70 ꢁ 104
0.65 ꢁ 104
317
326
320
347
343
347
343
343
343
88
79
85
70
74
67
72
72
71
400
450
500
550
600
λ / nm
Figure 6. (a) UV–Vis absorption of 18–23 and 25–30 (2 ꢁ 10ꢂ5 M) and (b)
fluorescence emission spectra of compounds 18–23 (c = 1 ꢁ 10ꢂ6 M) and 25–30
(c = 1 ꢁ 10ꢂ7 M) in methanol, excited at kabsꢂmax in methanol.
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
6
the activity of synthesized compounds against bacteria minimum
inhibitory concentrations (MICs) were determined and given in
Table 2 for selected compounds. Generally, results of antibacterial
evaluations revealed that compounds 5–38a did not exhibit
antibacterial activities against tested Gram-positive and Gram-
negative bacteria, with the exception of some selective activity
against Moraxella catarrhalis displayed by heterocycles–1,2,3-tria-
zole hybrids containing halogen-substituted aromatic (9, 11–13,
15, 17, 25 and 28) and coumarin (22 and 29) unit (Table 2). Com-
28 bearing p-fluoro- and p-chlorophenyl substituted triazole
exhibited marginal inhibitory effect against M. catarrhalis. The
incorporation of coumarin subunit to triazole revealed 5-iodoin-
dole 22 and 2-aryl-5-methylbenzothiazole 29 analogs with
anti-Moraxella catarrhalis activity (MICs 16 and 60.25 lg/mL,
respectively). The exceptional potency of compound 29 with MIC
value comparable to azitromycin was observed. The substitution
at C-7 of the coumarin ring seemed to have considerable impact
on the antibacterial activity since MIC values of 22 and 29 with
7-hydoxyl substituent were much lower than the MICs of their
pounds having MIC values higher than 128 lg/mL against all bac-
terial strains were considered inactive and were not included in
7-methyl-substituted analogs 23 and 30 (MICs > 128 lg/mL).
the Table 2.
Among
conjugates, compounds
p-fluorophenyl 4-substituted triazoles exhibited the highest anti-
Moraxella catarrhalis activity (MICs 0.5 and 1 g/mL, respectively).
However, the activity of these compounds was 2–4 fold lower
In addition, the relationship between anti-Moraxella catarrhalis
activity and lipophilicity of the evaluated compounds was
observed. It was found that lipophilic character of compounds
was important parameter related to membrane permeation in bio-
logical system because many processes of drug disposition depend
on the capability to cross membranes. Moreover, many of the
proteins involved in drug disposition have hydrophobic binding
sites thereby further enhance the importance of lipophilicity.51
Therefore, the octanol/water partition coefficients ClogP being a
measure of hydrophobicity/lipophilicity were calculated (Schemes
1–3). Generally, compounds exhibiting ClogP < 3 were deprived of
antibacterial activities against tested strains. Thus, 1,2,3-triazole
based bis-heterocycles (31a,b–38a, Scheme 3) bearing aliphatic
penciclovir-like side chain with ClogP amounting between ꢂ0.1
and 2.82 demonstrated the lack of antibacterial potency (MICs
the
unsubstituted
benzimidazole–1,2,3-triazole
9
and 13 with p-chlorophenyl and
l
than that for the reference antibacterial drug azitromycin
(MIC 0.25
activities
l
g/mL). Furthermore, observed anti-Moraxella catarrhalis
of benzimidazole–1,2,3-triazole conjugates 11
g/mL), 15 (MIC 128 g/mL) and 17 (MIC 16 g/mL) with
(MIC 16
l
l
l
variously substituted benzene ring were lower and unrelated to
substituents and their positions at the benzene ring. In the
2-methylbenzimidazole series, only compound 12 with 4-[p-(tri-
fluoromethyl)phenyl]triazole subunit showed weak activity, while
among benzothiazole–1,2,3-triazole hybrids, compounds 25 and
Table 2
Antimicrobial activities of selected compounds 9, 11, 12, 13, 15, 17, 22, 25, 28 and 29 against Gram-positive bacteria S. aureus, S. pneumoniae and S. pyogenes and Gram-negative
bacteria E. coli, M. catarrhalis and H. influenzae
R5
X
H3C
R2
S
N
NH
R1
N
N
R1
N
N
N
N
N
9, 11, 12, 13, 15, 17, 22
25, 28, 29
MIC (lg/mL)
Compd
9
R1
S. aureus
>128
S. pneumoniae
>128
S. pyogenes
E. coli
>128
>128
>128
>128
M. catarrhalis
H. influenzae
>128
Cl
>128
0.5
16
64
1
CF3
CF3
F
11
>128
>128
>128
>128
12
>128
>128
>128
>128
13
>128
>128
>128
>128
15
17
22
>128
>128
>128
>128
>128
>128
>128
>128
>128
>128
>128
>128
128
16
>128
>128
>128
F
Cl
Cl
O
O
OH
16
F
25
28
>128
>128
>128
>128
>128
>128
>128
>128
128
64
>128
>128
Cl
O
O
OH
29
>128
2
>128
0.25
>128
>128
8
60.25
>128
2
Azithromycin
0.125
0.25
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7
S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
Table 3
3. Conclusions
Most probable biological targets as predicted by PASSa for benzothiazole–1,2,3-
triazole–coumarin hybrid 29
The concept of molecular hybridization was adopted for design
and synthesis of diversified library of benzofused nitrogen/sulfur
heterocycle–1,2,3-triazole conjugates to evaluate their antibacterial
activities. For introduction the 1,2,3-triazole core in target mole-
cules eco-friendly click chemistry was applied under microwave
irradiation in a mixture of water and organic solvent. Copper(I)-cat-
alyzed Huisgen 1,3-dipolar cycloaddition gave regioselective
1,4-disubstituted 1,2,3-triazole tethered benzimidazole, indole
and 2-arylbenzothiazole containing halogen-substituted aromatic
(1–17 and 25–28) or coumarin (18–23 and 29–30) subunit, whereas
post-N-alkylation of unsubstituted NH-1,2,3-triazoles afforded both
2,4- (31a–34a) and 1,4-disubstituted (31b–33b) 1,2,3-triazole iso-
mers with penciclovir-like side chain (31a,b–38a). The structure
of 1H-1,2,3-triazole tautomeric form of 1,2,3-triazole–benzimida-
zole hybrid 5 was unambiguously confirmed by X-ray crystal
structure analysis. The compounds 18–23 and 25–30 revealed
fluorescence in the violet region of the visible spectrum with
2-arylbenzothiazole–1,2,3-triazole–7-hydroxycoumarin hybrid 29
displaying a maximum emission intensity. A strong influence of
phenyl spacer in 25–30 was observed on both the emission intensity
and maximum wavelength causing increased emission intensity
and a red shift in the emission wavelength.
O
H
O
O
H3C
S
N
NH
N
N
N
29
Biological targets
Pa
Pi
Transcription factor inhibitor
Transcription factor STAT inhibitor
Leukotriene synthesis inhibitor
MAP kinase inhibitor
Transglutaminase 2 inhibitor
Transcription factor STAT3 inhibitor
CYP2A11 substrate
Interleukin 2 agonist
Proto-oncogene tyrosine-protein kinase Fgr inhibitor
HMGCS2 expression enhancer
0.751
0.560
0.466
0.426
0.379
0.398
0.378
0.383
0.340
0.349
0.003
0.011
0.004
0.003
0.002
0.034
0.030
0.063
0.032
0.076
a
Activity spectrum predicted by PASS is presented by the list of activities with
the probabilities ‘to be active’ (Pa) and ‘to be inactive’ (Pi) calculated for each
activity. Increased Pa and decreased Pi, the more probable is predicted activity. The
list is arranged in descending order of Pa–Pi; therefore, more probable activities are
at the top of the list.
Among the tested compounds, benzimidazole–1,2,3-triazoles 9
with p-chlorophenyl and 13 with p-fluorophenyl linked to
4-position of the triazole significantly inhibited the growth of
human respiratory tract pathogen M. catarrhalis (MICs 0.5 and
were >128 lg/mL). In comparison to this series, compounds that
exhibited antibacterial activities against M. catarrhalis had higher
lipophilic properties with increased ClogP values in the range
3.14–6.24, with the logP value of 4.99 for the most active
compound 29. This observation is consistent with the previous
findings which demonstrated the increased susceptibility of
M. catarrhalis to hydrophobic agents due to its distinctive outer
membrane properties.52 Specifically, cells of M. catarrhalis have
on their surface low molecular weight lipopolisaccharides (LPS),
also called lipooligosaccharides (LOS), which contribute to the
increased hydrophobicity of its outer membrane. Other two
Gram-negative bacterial species tested have different outer mem-
brane structure, including the presence of LPS in E. coli, that is, less
hydrophobic than LOS53 and the presence of an additional capsule
on the surface of H. influenzae strain tested, that contribute to the
increased barrier function of these organisms. Therefore, among
the Gram-negative organisms tested M. catarrhalis has the cell
envelope with the highest permeability to lipophilic agents
enabling higher cellular uptake and enhanced intracellular action.
In line with this, biological potential of selected candidate 29
was estimated using program PASS, (Prediction of Activity Spectra
for Substances) (Table 3 and Table S2) that is, widely utilized for
prediction of pharmacotherapeutic effects and biological targets
for drug-like compounds based on the SAR analysis of known com-
pounds with experimentally established biological activity
spectra.54
Thus, the PASS prediction for the compound 29 indicated tran-
scription factor as the most plausible target (Pa = 0.75, Table 3). As
the literature precedents attest,21,22,55 some benzofused hetero-
cyclic derivatives were identified as a small-molecule effective
inhibitors of bacterial transcription factors within the AraC family
proteins, including those related to MAR (multiple adaptational
response) transcription factors such as MarA, SoxS, Rob, ExsA, LcrF
that are essential for regulation of the expression of a virulence
determinant. The exact cellular action of here presented com-
pounds in M. catarrhalis is not known at present but could be at
any or several of these previously shown targets. Further studies
are needed to elucidate the mechanism of action of here presented
compound class.
1
l
g/mL, respectively). Moreover, benzothiazole–1,2,3-triazole–
coumarin hybrid 29 showed anti-Moraxella catarrhalis potency
(MIC 6 0.25 g/mL) comparable to that of the reference antibiotic
l
azithromycin. Relationship between anti-Moraxella catarrhalis
activity and lipophilicity indicated that compounds showing
antibacterial efficacy had increased ClogP values that may be
related to their improved membrane permeability. To conclude,
applied molecular hybridization approach allowed us to identify
compound that satisfied our goal of identifying novel chemical
entity with selective antibacterial potential worthy of optimizing
as an anti-Moraxella catarrhalis agent.
4. Experimentals
4.1. Materials and methods
All solvents were dried/purified following recommended drying
agents and/or distilled over 3 Å molecular sieves. For monitoring
the progress of a reaction and for comparison purpose, thin layer
chromatography (TLC) was performed on pre-coated Merck silica
gel 60F-254 plates using an appropriate solvent system and the
spots were detected under UV light (254 nm). For column chro-
matography silica gel (Fluka, 0.063–0.2 mm) was employed, glass
column was slurry-packed under gravity. Melting points (uncor-
rected) were determined with Kofler micro hot-stage (Reichert,
Wien). Microwave-assisted syntheses were performed in a Mile-
stone start S microwave oven using glass cuvettes at 80 °C and
300 W under the pressure of 1 bar. UV absorption spectra were
recorded on Varian Cary 50 spectrophotometer operated in dou-
ble-beam mode. Fluorescence measurements were carried out on
a Varian Cary Eclipse fluorescence spectrophotometer. 1H and 13C
NMR spectra were acquired on a Bruker 300 and 600 MHz NMR
spectrometer. All data were recorded in DMSO-d6 at 298 K. Chem-
ical shifts were referenced to the residual solvent signal of DMSO at
d 2.50 ppm for 1H and d 39.50 ppm for 13C. Individual resonances
were assigned on the basis of their chemical shifts, signal intensi-
ties, multiplicity of resonances and H–H coupling constants. Mass
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
8
spectra were recorded on an Agilent 6410 instrument equipped
with electrospray interface and triple quadrupole analyzer (LC/
MS/MS). High performance liquid chromatography was performed
on an Agilent 1100 series system with UV detection (photodiode
array detector) using Zorbax C18 reverse-phase analytical column
7.33 (dd, 1H, J = 2.6 Hz, JH-F = 9.9 Hz, H-4), 7.02 (td, 1H, J = 2.6 Hz,
JH-F = 9.2 Hz, H-6), 6.46 (dd, 1H, J = 3.2 Hz, JH-F = 0.8 Hz, H-3), 5.09
(d, 2H, J = 2.5 Hz, H-10), 3.39 (t, 1H, J = 2.5 Hz, H-30). 13C NMR
(151 MHz, DMSO) (d/ppm): 157.22 (C-5, JC-F = 232.1 Hz), 132.21
(C-7a), 130.17 (C-2), 128.59 (C-3a, JC-F = 10.5 Hz), 111.02 (C-7, JC-F
=
(2.1 ꢁ 30 mm, 3.5
l
m). All compounds used for biological evalua-
9.8 Hz), 109.39 (C-6, JC-F = 26.2 Hz), 105.12 (C-4, JC-F = 23.3 Hz),
101.35 (C-3, JC-F = 4.7 Hz), 79.04 (C-20), 75.55 (C-30), 35.31 (C-10).
MS (ESI): m/z = 174.1 ([M+H]+). Anal. calcd For C11H8FN: C,
76.29; H, 4.66; N, 8.09. Found: C, 76.26; H, 4.65; N, 8.07.
tion showed >95% purity in this HPLC system.
4.2. Procedures for the preparation of compounds
4.2.1. General procedure for N-alkylation with propargyl
bromide
4.2.2. General procedure for the synthesis of NH-1,2,3-triazoles
5–8
To
a solution of corresponding heterocycle base in dry
Corresponding propargylated base (1–4) was dissolved in sol-
vent mixture DMF/CH3OH = 9:1 under argon atmosphere. CuI
(0.05 equiv) and TMSN3 (1.5 equiv) were added and reaction mix-
ture was heated at 100 °C. After 8 h, solvents were removed under
reduced pressure and the residue was purified by column
chromatography.
dimethylformamide (DMF), K2CO3 (1 equiv) was added. The reac-
tion mixture was stirred for 30 min under argon atmosphere and
propargyl bromide (1 equiv) was added. The mixture was heated
at 60 °C and stirred over night. Solvent was evaporated and the
residue was purified by column chromatography.
4.2.1.1. 1-(Prop-2-yn-1-yl)-1H-benzo[d]imidazole 1.
pound 1 was synthesized according to the general procedure using
benzimidazole (800 mg, 6.77 mmol). Purification by column chro-
Com-
4.2.2.1.
5.
1-[(1,2,3-Triazol-4-yl)methyl]-1H-benzo[d]imidazole
Compound 5 was synthesized according to the general pro-
cedure using compound 1 (550 mg, 3.53 mmol). After purification
by column chromatography (CH2Cl2/CH3OH = 10:1) compound 5
(430 mg, 61%, mp = 187–189 °C) was isolated as colourless crys-
tals. 1H NMR (300 MHz, DMSO) mixture of 1,4- and 2,4-tautomers
in ratio 1:2 (d/ppm): 15.21 (bs, 1H, NH), 14.90 (bs, 2H, NH), 8.32 (s,
1H, H-2), 8.14 (bs, 1H, H-30), 7.78 (bs, 2H, H-30), 7.53–7.68 (m, 6H,
H-4, H-7), 7.18–7.24 (m, 6H, H-5, H-6), 5.59 (s, 6H, CH2-10). 13C
NMR (151 MHz, DMSO) (d/ppm): 143.91 (C-2), 143.46 (C-20),
141.82 (C-3a), 133.55 (C-7a), 134.42 (C-30), 122.32 (C-5), 121.55
(C-6), 119.40 (C-4), 110.56 (C-7), in DMSO (C-10). MS (ESI): m/z =
200.1 ([M+H]+). Anal. calcd For C10H9N5: C, 60.29; H, 4.55;
N, 35.16. Found: C, 60.33; H, 4.56; N, 35.02.
matography (CH2Cl2/CH3OH = 20:1) yielded yellow oil of
1
(890 mg, 84%). 1H NMR (600 MHz, DMSO) (d/ppm): 8.27 (s, 1H,
H-2), 7.68 (d, 1H, J = 7.5 Hz, H-7), 7.64 (d, 1H, J = 7.5 Hz, H-4),
7.31 (t, 1H, J = 7.5 Hz, H-6), 7.24 (t, 1H, J = 7.5 Hz, H-5), 5.20 (d,
2H, J = 2.5 Hz, H-10), 3.48 (t, 1H, J = 2.5 Hz, H-30). 13C NMR
(151 MHz, DMSO) (d/ppm): 143.18 (C-2), 133.27 (C-3a), 131.39
(C-7a), 122.59 (C-6), 121.90 (C-5), 119.47 (C-4), 110.61 (C-7),
78.11 (C-20), 76.15 (C-30), 33.76 (C-10). MS (ESI): m/z = 157.1 ([M
+H]+). Anal. calcd for C10H8N2: C, 76.90; H, 5.16; N, 17.94. Found:
C, 76.81; H, 5.15; N, 17.89.
4.2.1.2.
2.
2-Methyl-1-(prop-2-yn-1-yl)-1H-benzo[d]imidazole
Compound 2 was synthesized according to the general pro-
4.2.2.2. 2-Methyl-1-[(1,2,3-triazol-4-yl)methyl]-1H-benzo[d]im-
cedure using 2-methylbenzimidazole (200 mg, 1.51 mmol). Purifi-
cation by column chromatography (CH2Cl2/CH3OH = 20:1) yielded
colourless oil of 2 (188 mg, 74%). 1H NMR (600 MHz, DMSO) (d/
ppm): 7.52–7.57 (m, 2H, H-4, H-7), 7.13–7.24 (m, 2H, H-5, H-6),
5.12 (d, 2H, J = 2.5 Hz, H-10), 3.39 (t, 1H, J = 2.5 Hz, H-30), 2.57 (s,
3H, CH3). 13C NMR (151 MHz, DMSO) (d/ppm): 151.90 (C-2),
142.70 (C-3a), 135.15 (C-7a), 122.15 (C-6), 121.95 (C-5), 118.79
(C-4), 110.30 (C-7), 78.86 (C-20), 75.80 (C-30), 32.94 (C-10), 13.84
(CH3). MS (ESI): m/z = 171.1 ([M+H]+). Anal. calcd For C11H10N2:
C, 77.62; H, 5.92; N, 16.46. Found: C, 77.59; H, 5.90; N, 16.47.
idazole 6.
eral procedure using compound
Compound 6 was synthesized according to the gen-
(500 mg, 2.94 mmol).
2
Purification by column chromatography (CH2Cl2/CH3OH = 10:1)
gained compound 6 (193 mg, 31%, mp = 237–239 °C) as white
solid. 1H NMR (600 MHz, DMSO) mixture of 1,4- and 2,4-tautomers
in ratio 1:2 (d/ppm): 15.17 (bs, 1H, NH), 14.88 (bs, 2H, NH), 8.12
(bs, 1H, H-30), 7.77 (bs, 2H, H-30), 7.56 (d, 3H, J = 7.1 Hz, H-7),
7.50 (d, 3H, J = 7.6 Hz, H-4), 6.90–7.31 (m, 6H, H-5, H-6), 5.50 (s,
6H, CH2-10), 2.63 (s, 9H, CH3). 13C NMR (75 MHz, DMSO) (d/
ppm):152.15 (C-2), 144.69 (C-20), 142.77 (C-3a), 135.39 (C-7a),
132.60 (C-30), 121.94 (C-5), 121.73 (C-6), 118.64 (C-4), 110.41 (C-
7), 38.48 (C-10), 14.12 (CH3). MS (ESI): m/z = 214.1 ([M+H]+). Anal.
calcd For C11H11N5: C, 61.96; H, 5.20; N, 32.84. Found: C, 61.82;
H, 5.21; N, 32.89.
4.2.1.3. 5-Iodo-1-(prop-2-yn-1-yl)-1H-indole 3.
Compound
3 was synthesized according to the general procedure using 5-
iodoindole (3 g, 12 mmol). Purification by column chromatography
(n-hexane/ethyl acetate = 10:1) yielded yellow oil of 3 (3 g, 67%).
1H NMR (600 MHz, DMSO) (d/ppm): 7.89 (1H, d, J = 1.5 Hz, H-2),
7.34–7.40 (2H, m, H-4, H-6), 6.44 (1H, d, J = 3.1 Hz, H-3) 6.39
(1H, d, J = 6.0 Hz, H-7), 5.04 (2H, d, J = 2.5 Hz, H-10), 3.36 (1H, t,
J = 2.5 Hz, H-30). 13C NMR (75 MHz, DMSO) (d/ppm): 135.07 (C-
7a), 131.54 (C-3a), 129.86 (C-4), 129.70 (C-2), 129.41 (C-6),
113.02 (C-7), 101.18 (C-3), 83.77 (C-5), 79.39 (C-20), 76.15 (C-30),
35.68 (C-10). MS (ESI): m/z = 171.1 ([M+H]+). Anal. calcd For
4.2.2.3.
7.
5-Iodo-1-[(1,2,3-triazol-4-yl)methyl]-1H-indole
Compound 7 was synthesized according to the general pro-
cedure using compound 3 (200 mg, 0.71 mmol). After purification
by column chromatography (n-hexane/ethyl-acetate = 1:1) com-
pound 7 (123 mg, 54%, mp = 119–121 °C) was isolated as yellow
solid. 1H NMR (300 MHz, DMSO) of mixture of 1,4- and 2,4-tau-
tomers in ratio 1:2 (d/ppm): 15.06 (bs, 1H, NH), 14.86 (bs, 2H,
NH), 7.91 (s, 1H, H-2), 7.67 (bs, 1H, H-30), 7.57 (bs, 2H, H-30),
7.32–7.46 (m, 9H, H-4, H-6, H-7), 6.42 (d, 3H, J = 3.1 Hz, H-3),
5.47 (s, 6H, CH2-10). 13C NMR (151 MHz, DMSO) (d/ppm): 144.12
(C-20), 135.20 (C-7a), 132.83 (C-3a), 131.49 (C-4), 130.24 (C-2),
129.51 (C-6), 129.29 (C-30), 113.08 (C-7), 100.94 (C-3), 83.45 (C-
5), 41.23 (C-10). MS (ESI): m/z = 325.0 ([M+H]+). Anal. calcd For
C11H8IN: C, 47.00; H, 2.87; N, 4.98. Found: C, 47.19; H, 2.86; N,
4.99.
4.2.1.4. 5-Fluoro-1-(prop-2-yn-1-yl)-1H-indole 4.
Com-
pound 4 was synthesized according to the general procedure using
5-fluoroindole (300 mg, 2.22 mmol). Purification by column chro-
matography (n-hexane/ethyl-acetate = 10:3) yielded yellow oil of
4 (125 mg, 33%). 1H NMR (300 MHz, DMSO) (d/ppm): 7.52 (dd,
1H, J = 9.0 Hz, JH-F = 4.5 Hz, H-7), 7.46 (d, 1H, J = 3.2 Hz, H-2),
C11H9IN4: C, 40.76; H, 2.80; N, 17.29. Found: C, 40.85; H, 2.81; N,
17.35.
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
4.2.2.4.
8.
5-Fluoro-1-[(1,2,3-triazol-4-yl)methyl]-1H-indole
Compound 8 was synthesized according to the general pro-
4.2.3.3. 1-{[1-(4-(Trifluoromethyl)phenyl)-1H-1,2,3-triazol-4-yl]
methyl}-1H-benzo[d]imidazole 11. Compound 11 was syn-
cedure using compound 4 (125 mg, 0.72 mmol). After purification
by column chromatography (n-hexane/ethyl-acetate = 10:3) com-
pound 8 (101 mg, 65%) was isolated as yellow oil. 1H NMR
(300 MHz, DMSO) of mixture of 1,4- and 2,4-tautomers in ratio
1:2 (d/ppm): 15.15 (bs, 1H, NH), 14.82 (bs, 2H, NH), 8.02 (bs, 1H,
H-12), 7.66 (bs, 2H, H-12), 7.50–7.56 (m, 6H, H-7, H-2), 7.29 (dd,
3H, J = 2.3 Hz, JH-F = 9.9 Hz, H-4), 6.97 (td, 3H, J = 2.4 Hz, JH-F
= 9.3 Hz, H-6), 6.43 (d, 3H, J = 2.0 Hz, H-3), 5.48 (s, 6H, CH2-10).
13C NMR (151 MHz, DMSO) (d/ppm): 157.08 (C-5, JC-F = 232.0 Hz),
143.75 (C-20), 132.37 (C-30), 132.33 (C-7a), 130.55 (C-2), 128.49
(C-3a, JC-F = 10.5 Hz), 111.08 (C-7, JC-F = 9.8 Hz), 109.39 (C-6, JC-F
= 26.1 Hz), 104.96 (C-4, JC-F = 23.0 Hz), 101.09 (C-3, JC-F = 4.7 Hz),
40.81 (C-10). MS (ESI): m/z = 217.1 ([M+H]+). Anal. calcd For
thesized according to the general procedure using compound 1
(50 mg, 0.32 mmol) and 1-azido-4-(trifluoromethyl)benzene
(71 mg, 0.38 mmol), Cu(0) (20 mg, 0.32 mmol) and 1 M CuSO4
solution (0.07 mL) in a mixture of tert-BuOH/H2O = 1:1 (5 mL).
After purification by column chromatography (CH2Cl2/CH3
OH = 40:1) compound 11 was isolated as white powder (92 mg,
84%, mp = 188–190 °C. 1H NMR (300 MHz, DMSO) (d/ppm): 8.97
(s, 1H, H-2), 8.50 (s, 1H, H-30), 8.08 (d, 2H, J = 8.5 Hz, H-60, 600),
7.92 (d, 2H, J = 8.5 Hz, H-50, H-500), 7.68 (s, 2H, H-4, H-7), 7.19–
7.28 (m, 2H, H-5, H-6), 5.65 (s, 2H, H-10). 13C NMR (151 MHz,
DMSO) (d/ppm): 143.93 (C-2), 141.76 (C-20), 139.22 (C-3a),
129.21 (C-7a), 128.80 (q, J = 129.3 Hz, C-70), 127.15 (d, J = 12 Hz,
C-40), 126.55 (q, J = 181 Hz, CF3), 124.66 (C-5), 122.60 (d,
J = 30 Hz, C-50,500), 122.35 (C-6), 121.8 (d, J = 66 Hz, C-60,600),
120.62 (C-30), 119.34 (C-4), 116.59 (C-7), 76.17 (C-10). MS (ESI):
m/z = 344.1 ([M+H]+). Anal. calcd For C17H12F3N5: C, 59.48; H,
3.52; N, 20.40. Found: C, 59.40; H, 3.51; N, 20.32.
C11H9FN4: C, 61.10; H, 4.20; N, 25.91. Found: C, 61.26; H, 4.19; N,
25.85.
4.2.3. General procedure for the synthesis of 1,2,3-triazole based
bis-heterocycles 9–23 and 25–30
The synthesis of halogen-substituted aromatic azides was per-
formed from the corresponding arylamines according to the litera-
ture procedure.35 The corresponding N-propargylated heterocycle
4.2.3.4. 1-{[1-(4-(Trifluorometil)phenyl)-1H-1,2,3-triazol-4-yl]
methyl}-2-methyl-1H-benzo[d]imidazole
12.
Compound
12 was synthesized according to the general procedure using com-
pound 2 (50 mg, 0.35 mmol) and 1-azido-4-(trifluoromethyl)ben-
zene (65 mg, 0.30 mmol), Cu(0) (22.2 mg, 0.35 mmol) and 1 M
CuSO4 solution (0.07 mL) in a mixture of tert-BuOH/H2O = 1:1
(5 mL). After purification by column chromatography (CH2Cl2/CH3
OH = 20:1) compound 12 was isolated as yellow powder (72 mg,
74%, mp = 193–195 °C). 1H NMR (600 MHz, DMSO) (d/ppm): 9.02
(s, 1H, H-30), 8.13 (d, 2H, J = 8.5 Hz, H-50,500), 7.96 (d, 2H,
J = 8.6 Hz, H-4, H-7), 7.58 (dd, 2H, JH-F = 67.1 Hz, JH-H = 7.7 Hz, H-
60,600), 7.07–7.25 (m, 2H, H-5, H-6), 5.60 (s, 2H, H-10), 2.70 (s, 3H,
CH3). 13C NMR (151 MHz, DMSO) (d/ppm): 144.12 (C-2), 139.20
(C-20), 132.22 (C-3a), 128.73 (d, J = 32.4 Hz, C-70), 127.12 (d,
J = 3.7 Hz, C-50,500), 124.70 (C-5), 122.89 (C-6), 122.00 (C-7a),
121.65 (q, J = 170 Hz, CF3), 121.41 (d, J = 19.1 Hz, C-60,600), 120.58
(C-40), 118.22 (C-30), 115.63 (C-4), 110.11 (C-7), 38.19 (C-10),
13.78 (CH3). MS (ESI): m/z = 358.1 ([M+H]+). Anal. calcd For
(1–4) (1 equiv) was dissolved in
a mixture of tert-BuOH/
H2O = 1:1 and azide (1.2 equiv), Cu(0) (1 equiv) and 1 M CuSO4
solution were added. The reaction mixture was then stirred under
microwave irradiation (300 W) at 80 °C during 30 min. The solvent
was removed under reduced pressure and the residue was purified
by column chromatography.
4.2.3.1. 1-{[1-(4-Chlorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-
1H-benzo[d]imidazole 9.
Compound 9 was synthesized
according to the general procedure using compound 1 (50 mg,
0.32 mmol) and 1-azido-4-chlorobenzene (59 mg, 0.38 mmol), Cu
(0) (20 mg, 0.32 mmol) and 1 M CuSO4 solution (0.08 mL) in a mix-
ture of tert-BuOH/H2O = 1:1 (5 mL). After purification by column
chromatography (CH2Cl2/CH3OH = 50:1) compound 9 was isolated
as powder (88 mg, 89%; mp = 158–160 °C). 1H NMR (300 MHz,
DMSO) (d/ppm): 8.91 (s, 1H, H-2), 8.41 (s, 1H, H-30), 7.90 (d, 2H,
J = 7.6 Hz, H-60,600), 7.63–7.68 (m, 4H, H-4, H-7, H-50,500), 7.20–
7.28 (m, 2H, H-5, H-6), 5.67 (s, 2H, H-10). 13C NMR (151 MHz,
DMSO) (d/ppm): 143.77 (C-2), 141.81 (C-20), 135.25 (C-3a),
133.02 (C-70), 131.26 (C-7a), 130.08 (C-40), 129.8 (C-50, 500),
122.41 (C-5), 122.11 (C-6), 121.83 (C-60,600), 121.61 (C-30), 119.48
(C-4), 110.67 (C-7), 39.92 (C-10). MS (ESI): m/z = 310.1 ([M+H]+).
Anal. calcd For C16H12ClN5: C, 62.04; H, 3.90; N, 22.61. Found: C,
61.99; H, 3.89; N, 22.55.
C18H14F3N5: C, 60.50; H, 3.95; N, 19.60. Found: C, C, 60.58; H,
3.94; N, 19.57.
4.2.3.5. 1-{[1-(4-Fluorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-
1H-benzo[d]imidazole 13.
Compound 13 was synthesized
according to the general procedure using compound 1 (40 mg,
0.26 mmol) and 1-azido-4-fluorobenzene (43 mg, 0.31 mmol), Cu
(0) (16.5 mg, 0.26 mmol) and 1 M CuSO4 solution (0.05 mL) in a
mixture of tert-BuOH/H2O = 1:1 (5 mL). After purification by col-
umn chromatography (CH2Cl2/CH3OH = 40:1) oily compound 13
was isolated (57 mg, 76%). 1H NMR (300 MHz, DMSO) (d/ppm):
8.80 (s, 1H, H-2) 8.47 (s, 1H, H-30), 7.87–7.91 (m, 2H, H-60,600),
7.66 (s, 2H, H-4, H-7), 7.31–7.44 (m, 2H, H-50,500), 7.09–7.30 (m,
2H, H-5, H-6), 5.61 (s, 2H, H-10). 13C NMR (75 MHz, DMSO) (d/
ppm): 162.15 (d, J = 243.8 Hz, C-70), 144.11 (C-2), 133.48 (C-20),
123.09 (C-3a), 122.95 (d, J = 9 Hz, C-40), 122.81 (C-7a), 122.60 (d,
J = 74.3 Hz, C-60,600), 122.20 (d, J = 15.8 Hz, C-50,500), 119.96 (C-5),
119.03 (C-6), 117.34 (d, J = 23.3 Hz, C-4), 111.27 (C-30), 76.64 (C-
7) 68.19 (C-10). MS (ESI): m/z = 294.1 ([M+H]+). Anal. calcd For
4.2.3.2. 1-{[1-(4-Chlorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-2-
methyl-1H-benzo[d]imidazole 10.
Compound 10 was syn-
thesized according to the general procedure using compound 2
(50 mg, 0.29 mmol) and 1-azido-4-chlorobenzene (54.2 mg,
0.35 mmol), Cu(0) (18.4 mg, 0.29 mmol) and 1 M CuSO4 solution
(0.07 mL) in a mixture of tert-BuOH/H2O = 1:1 (5 mL). After purifi-
cation by column chromatography (CH2Cl2/CH3OH = 50:1) com-
pound 10 was isolated as yellow powder (80 mg, 84%, mp = 115–
1
117 °C). H NMR (600 MHz, DMSO) (d/ppm): 8.92 (s, 1H, H-30),
7.90 (d, 2H, J = 6 Hz, H-60,600), 7.71 (d, 1H, J = 6 Hz, H-4), 7.66 (d,
2H, J = 6 Hz, H-50,500), 7.57 (d, 1H, J = 6 Hz, H-7), 7.25 (t,1H,
J = 6 Hz, H-6), 7.21 (t, 1H, J = 6 Hz, H-5), 5.63 (s, 2H, H-10), 2.74 (s,
3H, CH3). 13C NMR (151 MHz, DMSO) (d/ppm): 151.88 (C-2),
143.60 (C-20), 135.21 (C-3a), 133.44 (C-70), 133.04 (C-7a), 129.80
(C-50,500), 129.69 (C-40), 122.12 (C-5, C-6), 122.00 (C-30), 121.82
(C-60,600), 117.55 (C-4), 110.42 (C-7), 38.29 (C-10), 13.45 (CH3). MS
(ESI): m/z = 324.1 ([M+H]+). Anal. calcd For C17H14ClN5: C, 63.06;
H, 4.36; N, 21.63. Found: C, 63.14; H, 4.35; N, 21.71.
C16H12FN5: C, 65.52; H, 4.12; N, 23.88. Found: C, 65.46; H, 4.13;
N, 23.82.
4.2.3.6. 1-{[1-(4-Fluorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-2-
methyl-1H-benzo[d]imidazole 14.
Compound 14 was syn-
thesized according to the general procedure using compound 2
(60 mg, 0.35 mmol) and 1-azido-4-fluorobenzene (58 mg,
0.42 mmol), Cu(0) (22.2 mg, 0.35 mmol) and 1 M CuSO4 solution
(0.06 mL) in
a mixture of tert-BuOH/H2O = 1:1 (5 mL). After
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10
purification by column chromatography (CH2Cl2/CH3OH = 50:1)
5.67 (s, 2H, H-10). 13C NMR (151 MHz, DMSO) (d/ppm): 143.88
(C-2), 138.04 (C-20), 135.16 (C-60, C-80), 133.89 (C-3a), 130.10 (C-
40), 128.10 (C-70), 122.55 (C-7a), 122.46 (C-50,500), 121.47 (C-4, C-
7), 122.04 (C-5, C-6), 118.82 (C-30), 39.82 (C-10). MS (ESI): m/
z = 344.1 ([M+H]+). Anal. calcd For C16H11Cl2N5: C, 55.83; H, 3.22;
N, 20.35. Found: C, 55.95; H, 3.21; N, 20.31.
compound 14 was isolated as powder (92 mg, 84%, mp = 188–
1
191 °C). H NMR (300 MHz, DMSO) (d/ppm): 8.87 (s, 1H, H-30),
7.90 (dt, 2H, J H-F = 10.4, JH-H = 4.1 Hz, H-50,500), 7,75 (dd, 2H,
JH-H = 7.3 Hz, JH-F = 43.6 Hz, H-60,600), 7.35–7.55 (m, 2H, H-4, H-7),
7.07–7.29 (m, 2H, H-5, H-6), 5.61 (s, 2H, H-10), 2.65 (s, 3H, CH3).
13C NMR (151 MHz, DMSO) (d/ppm): 161.65 (d, JCF = 245.9 Hz, C-
70), 143.73 (C-2), 132.22 (C-20), 123.62 (C-3a), 122.53 (d, JCF
4.2.3.10.
triazol-1-yl]methyl}-7-hydroxy-4a,8a-dihydro-2H-chromen-2-
on 18. 4-(Azidomethyl)-7-hydroxycoumarin and 4-(azido-
4-{4-[((1H-Benzo[d]imidazol-1-yl)methyl)-1H-1,2,3-
=
9.8 Hz, C-50,500), 122.11 (C-7a), 121.55 (C-5, C-6), 121.25 (C-40),
118.28 (C-30), 116.63 (d, J = 23.3 Hz, C-60,600),115.58 (C-4), 110.19
(C-7), 38.31 (C-10), 13.84 (CH3). MS (ESI): m/z = 308.1 ([M+H]+).
Anal. calcd For C17H14FN5: C, 66.44; H, 4.59; N, 22.79. Found: C,
66.37; H, 4.60; N, 22.83.
methyl)-7-methylcoumarin were synthesized in the reaction of
sodium azide with 4-chloromethyl-7-hydroxycoumarin and 4-
chloromethyl-7-methylcoumarin that were previously prepared
by Pechmann cyclization of m-hydroxyphenol or m-cresol with
4-chloroacetoacetate ethyl ester.36,37,56 Compound 18 was synthe-
sized according to the general procedure using compound 1
(50 mg, 0.32 mmol) and 4-(azidomethyl)-7-hydroxycoumarin
(82 mg, 0.38 mmol), Cu(0) (20.3 mg, 0.32 mmol) and 1 M CuSO4
solution (0.07 mL) in a mixture of tert-BuOH/H2O = 1:1 (5 mL).
After purification by column chromatography (CH2Cl2/CH3-
OH = 20:1) compound 18 was isolated as yellow powder (91 mg,
76%, mp = 184–187 °C). 1H NMR (300 MHz, DMSO (d/ppm): 10.69
(s, 1H, OH), 8.28–8.33 (m, 2H, H-2, H-30), 7.57–7.66 (m, 3H, H-600,
H-4, H-7), 7.10–7.30 (m, 2H, H-5, H-6), 6.71–6.85 (m, 3H, H-300,
H-700, H-900), 5.86 (s, 2H, H-40), 5.58 (s, 2H, H-10). 13C NMR
(151 MHz, DMSO) (d/ppm): 161.64 (C-200), 159.86 (C-800), 155.05
(C-400), 150.32 (C-1000), 143.56 (C-20), 143.10 (C-3a), 137.09 (C-7a),
125.96 (C-600), 124.74 (C-4), 122.35 (C-5, C-6), 121.60 (C-30),
119.41 (C-2), 113.15 (C-700), 110.59 (C-300), 109.32 (C-7), 109.28
(C-500), 102.50 (C-900), 49.17 (C-40), 40.37 (C-10). MS (ESI): m/
z = 376.1 ([M+H]+). Anal. calcd For C20H17N5O3: C, 63.99; H, 4.56;
N, 18.66. Found: C, 63.91; H, 4.55; N, 18.60.
4.2.3.7. 1-{[1-(2-Fluorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-
1H-benzo[d]imidazole 15.
Compound 15 was synthesized
according to the general procedure using compound 1 (40 mg,
0.26 mmol) and 1-azido-2-fluorobenzene (43 mg, 0.31 mmol), Cu
(0) (16.5 mg, 0.26 mmol) and 1 M CuSO4 solution (0.05 mL) in a
mixture of tert-BuOH/H2O = 1:1 (5 mL). After purification by col-
umn chromatography (CH2Cl2/CH3OH = 40:1) compound 15 was
isolated as white powder (64 mg, 85%, mp = 144–146 °C). 1H
NMR (300 MHz, DMSO) (d/ppm): 8.66 (d, 1H, JHF = 2.2 Hz, H-30),
8.40 (s, 1H, H-2), 7.76 (td, 1H, J = 7.8, 1.6 Hz, H-70), 7.66 (d, 2H,
J = 14.7 Hz, H-4, H-7), 7.45– 7.59 (m, 2H, H-70, H-80), 7.30–7.42
(m, 2H, H-60, H-90), 7.19 (dd, 2H, J = 15.2 Hz, 7.5 Hz, H-5, H-6),
5.63 (s, 2H, H-10). 13C NMR (151 MHz, DMSO) (d/ppm): 153.68 (d,
JCF = 250.4 Hz, C-50), 143.11 (C-3a, C-7a), 138.10 (C-20), 131.31
(d, JCF = 7.9 Hz, C-70), 125.84 (C-2), 125.57 (C-90), 125.52 (d, JCF
=
3.7 Hz, C-80), 124.56 (d, JCF = 10.8 Hz, C-40), 122.43 (C-6), 121.62
(C-4), 119.47 (C-30), 117.14 (C-60), 117.07 (d, JCF = 19.5 Hz, C-50),
117.01 (C-5), 110.74 (C-7), 67.70 (C-10). MS (ESI): m/z = 294.1 ([M
+H]+). Anal. calcd For C16H12FN5: C, 65.52; H, 4.12; N, 23.88. Found:
C, 65.56; H, 4.13; N, 23.91.
4.2.3.11.
triazol-1-yl]methyl}-7-methyl-4a,8a-dihydro-2H-chromen-2-
on 19. Compound 19 was synthesized according to the gen-
eral procedure using compound 1 (40 mg, 0.26 mmol) and 4-(azi-
domethyl)-7-methylcoumarin (67 mg, 0.31 mmol), Cu(0)
4-{4-[((1H-Benzo[d]imidazol-1-yl)methyl)-1H-1,2,3-
4.2.3.8. 1-{[1-(2-Fluorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-2-
methyl-1H-benzo[d]imidazole 16.
Compound 16 was syn-
thesized according to the general procedure using compound 2
(50 mg, 0.29 mmol) and 1-azido-2-fluorobenzene (48 mg,
0.35 mmol), Cu(0) (18.4 mg, 0.29 mmol) and 1 M CuSO4 solution
(0.06 mL) in a mixture of tert-BuOH/H2O = 1:1 (5 mL). After purifi-
cation by column chromatography (CH2Cl2/CH3OH = 40:1)
compound 16 was isolated as white powder (73 mg, 82%, mp =
170–173 °C). 1H NMR (300 MHz, DMSO) (d/ppm): 8.73 (d, 1H,
(16.5 mg, 0.26 mmol) and 1 M CuSO4 solution (0.05 mL) in a mix-
ture of tert-BuOH/H2O = 1:1 (5 mL). After purification by column
chromatography (CH2Cl2/CH3OH = 30:1) compound 19 was iso-
lated as yellow powder (64 mg, 67%, mp = 210–212 °C). 1H NMR
(300 MHz, DMSO) (d/ppm): 8.28–8.34 (m, 2H, H-2, H-30), 7.50–
7.74 (m, 3H, H-600, H-4, H-7), 7.09–7.35 (m, 4H, H-700, H-900, H-5,
H-6), 5.91 (s, 2H, H-70), 5.79 (s, 1H, h-300), 5.60 (s, 2H, H-10), 2.41
J
CF = 2.1 Hz, H-30), 7.79 (td, 2H, J = 7.9, 1.6 Hz, H-60, H-70), 7.48–
13
7.72 (m, 3H, H-80, H-4, H-7), 7.32–7.48 (m, 1H, H-90), 7.14–7.29
(m, 2H, H-5, H-6), 5.65 (s, 2H, H-10), 2.72 (s, 3H, CH3). 13C NMR
(151 MHz, DMSO) (d/ppm): 153.68 (d, J = 254.0 Hz, C-50) 143.11
(C-2), 131.33 (C-90), 131.28 (C-3a), 125.71 (C-80), 125.69 (d,
J = 46.8 Hz, C-70), 125.39 (d, J = 34.73 Hz, C-50), 124.60 (C-7a),
122.02 (d, J = 119.3 Hz, C-40), 119.47 (C-60), 118.22 (C-5, C-6),
117.14 (C-30), 117.01 (C-4), 110.74 (C-7), 67.70 (C-10), 19.07
(CH3). MS (ESI): m/z = 307.1 ([M+H]+). Anal. calcd For C17H14FN5:
C, 66.44; H, 4.59; N, 22.79. Found: C, 66.61; H, 4.60; N, 22.85.
(s, 3H, CH3). C NMR (151 MHz, DMSO) (d/ppm): 159.49 (C-200),
153.15 (C-400), 149.92 (C-1000), 143.50 (C-3a), 143.16 (C-800),
137.09 (C-7a), 127.07 (C-20), 114.59 (C-500), 125.58 (C-2), 124.71
(C-700), 124.36 (C-600), 119.46 (C-4), 116.79 (C-900), 122.33 (C-5, C-
6), 121.56 (C-30), 112.81 (C-300), 110.62 (C-7), 67.70 (C-40), 49.15
(C-10), 19.07 (CH3). MS (ESI): m/z = 374.2 ([M+H]+). Anal. calcd
For C21H19N5O2: C, 67.55; H, 5.13; N, 18.76. Found: C, 67.50; H,
5.12; N, 18.70.
4.2.3.12. 4-{4-[((2-Methyl-1H-benzo[d]imidazol-1-yl)methyl)-
1H-1,2,3-triazol-1-yl]methyl}-7-hydroxy-4a,8a-dihydro-2H-
4.2.3.9.
1-{[1-(3,5-Dichlorophenyl)-1H-1,2,3-triazol-4-yl]
Compound 17 was syn-
methyl}-1H-benzo[d]imidazole 17.
chromen-2-on 20.
Compound 20 was synthesized according
thesized according to the general procedure using compound 2
(50 mg, 0.32 mmol) and 1-azido-3,5-dichlorobenzene (71 mg,
0.38 mmol), Cu(0) (20.3 mg, 0.32 mmol) and 1 M CuSO4 solution
(0.06 mL) in a mixture of tert-BuOH/H2O = 1:1 (5 mL). After purifi-
cation by column chromatography (CH2Cl2/CH3OH = 40:1) com-
to the general procedure using compound 2 (40 mg, 0.26 mmol)
and 4-(azidomethyl)-7-hydroxycoumarin (62 mg, 0.29 mmol), Cu
(0) (16.5 mg, 0.26 mmol) and 1 M CuSO4 solution (0.05 mL) in a
mixture of tert-BuOH/H2O = 1:1 (5 mL). After purification by col-
umn chromatography (CH2Cl2/CH3OH = 40:1) compound 20 was
isolated as yellow powder (76 mg, 83%, mp = 205–207 °C). 1H
NMR (600 MHz, DMSO) (d/ppm): 10.92 (s, 1H, OH), 8.31 (s, 1H,
H-30), 7.44–7.68 (m, 3H, H-600, H-4, H-7), 7.04–7.25 (m, 2H, H-5,
H-6), 6.70–6.92 (m, 3H, H-300, H-700, H-900), 5.85 (s, 2H, H-40), 5.52
pound 17 was isolated as
a white powder (84 mg, 77%,
mp = 201–203 °C). 1H NMR (300 MHz, DMSO) (d/ppm): 8.91 (s,
1H, H-2), 8.41 (s, 1H, H-30), 7.91 (d, 2H, J = 9.01 Hz, H-4, H-7),
7.63–7.71 (m, 3H, H-5, H-6, H-70), 7.18–7.28 (m, 2H, H-50,500),
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
(s, 2H, H-10), 2.63 (s, 3H, CH3), 2.41 (s, 3H, CH3). 13C NMR (151 MHz,
DMSO) (d/ppm): 160.11 (C-200), 157.29 (C-800), 153.88 (C-400), 153.57
(C-1000), 145.39 (C-2), 144.48 (C-3a), 143.10 (C-20), 137.09 (C-7a),
128.09 (C-600), 126.74 (C-4), 123.66 (C-5, C-6), 123.44 (C-30),
120.36 (C-700), 115.46 (C-300), 112.13 (C-7), 104.74 (C-900), 102.25
(C-500), 51.38 (C-40), 40.37 (C-10), 15.88 (CH3). MS (ESI): m/z
= 390.2 ([M+H]+). Anal. calcd For C21H19N5O3: C, 64.77; H, 4.92;
N, 17.98. Found: C, 64.70; H, 4.91; N, 17.92.
144.00 (C-2), 135.12 (C-20), 131.50 (C-3a), 130.27 (C-5), 129.50
(C-7a), 129.30 (C-6), 126.09 (C-700), 125.97 (C-600), 124.86 (C-30),
117.29 (C-900), 115.09 (C-500), 113.25 (C-7), 113.11 (C-300), 100.93
(C-4), 83.55 (C-3), 49.60 (C-40), 41.42 (C-10), 21.54 (CH3). MS
(ESI): m/z = 498.1 ([M+H]+). Anal. calcd For C22H19IN4O2: C, 53.03;
H, 3.84; N, 11.24. Found: C, 52.94; H, 3.83; N, 11.28.
4.2.3.16. 2-[4-(Prop-2-yn-1-yl)aminophenyl]-6-methylbenzo[d]
thiazole 24.
To a solution of 2-(4-aminophenyl)-6-methyl-
4.2.3.13. 4-{4-[((2-Methyl-1H-benzo[d]imidazol-1-yl)methyl)-
1H-1,2,3-triazol-1-yl]methyl}-7-methyl-4a,8a-dihydro-2H-chro-
benzothiazole (2.88 g, 12 mmol) in dry acetone (100 mL) was
added anhydrous K2CO3 (8.82 g, 64 mmol) and reaction mixture
was further refluxed for 30 min. Subsequently, KI (996 mg,
6 mmol) and propargyl bromide (1.09 mL, 14.4 mmol) were added
and the reaction mixture was further refluxed for 24 h. After com-
pletion of the reaction, mixture was cooled, filtered, the filtrate was
evaporated in vacuo and purified by column chromatography
(CH2Cl2/CH3OH = 70:1) to give the compound 24 as yellow powder
(773 mg, 23%, mp = 176–178 °C). 1H NMR (300 MHz, DMSO) (d/
ppm): 7.77–7.82 (m, 4H, H-4, H-7, H-20,200), 7.26 (d, 1H, J = 8.3 Hz,
H-6), 6.71–6.75 (m, 3H, H-30,300, NH), 3.95 (dd, 2H, J = 5.9 Hz, H-
60), 3.10 (s, 1H, H-80), 2.41 (s, 3H, CH3). 13C NMR (151 MHz, DMSO)
(d/ppm): 166.79 (C-2), 151.97 (C-3a), 150.40 (C-10), 134.07 (C-7a),
133.95 (C-4), 128.32 (C-30,300), 127.60 (C-40), 121.50 (C-5), 121.46
(C-6), 121.30 (C-20,200), 112.61 (C-7), 81.48 (C-70), 73.27 (C-80),
31.75 (C-60), 20.94 (CH3). MS (ESI): m/z = 279.1 ([M+H]+). Anal.
calcd For C17H14N2S: C, 73.35; H, 5.07; N, 10.06. Found: C, 73.30;
H, 5.08; N, 10.03.
men-2-on 21.
Compound 21 was synthesized according to
the general procedure using compound 2 (40 mg, 0.26 mmol) and
4-(azidomethyl)-7-methylcoumarin (67 mg, 0.29 mmol), Cu(0)
(16.5 mg, 0.26 mmol) and 1 M CuSO4 solution (0.05 mL) in a mix-
ture of tert-BuOH/H2O = 1:1 (5 mL). After purification by column
chromatography (CH2Cl2/CH3OH = 40:1) compound 21 was iso-
lated as yellow powder (74 mg, 81%, mp = 128–130 °C). 1H NMR
(300 MHz, DMSO) (d/ppm): 8.30 (s, 1H, H-30), 7.46–7.74 (m, 3H,
H-600, H-4, H-7), 7.06–7.34 (m, 4H, H-700, H-900, H-5, H-6), 5.90 (s,
2H, H-40), 5.78 (s, 1H, H-300), 5.54 (s, 2H, H-10), 2.64 (s, 3H, CH3).
13C NMR (151 MHz, DMSO) (d/ppm): 161.71 (C-200), 155.36 (C-400),
152.11 (C-1000), 145.72 (C-3a), 145.34 (C-2), 137.09 (C-7a), 134.69
(C-20), 126.75 (C-700), 126.57 (C-600), 123.86 (C-5, C-6), 123.66 (C-
30), 120.24 (C-4), 116.80 (C-500), 119.00 (C-900), 115.05 (C-300),
112.31 (C-7), 51.36 (C-40), 40.49 (C-10), 23.22 (CH3), 15.85 (CH3).
MS (ESI): m/z = 388.2 ([M+H]+). Anal. calcd For C22H21N5O2: C,
68.20; H, 5.46; N, 18.08. Found: C, 68.01; H, 5.44; N, 18.15.
4.2.3.17.
2-{4-[((1-(4-Fluorophenyl)-1H-1,2,3-triazol-4-yl)
Com-
4.2.3.14. 4-{4-[((5-Iodo-1H-indol-1-yl)methyl)-1H-1,2,3-triazol-
1-yl]methyl}-7-hydroxy-4a,8a-dihydro-2H-chromen-2-on
methyl]aminophenyl}-6-methylbenzo[d]thiazole 25.
pound 25 was synthesized according to the general procedure
using compound 24 (150 mg, 0.54 mmol) and 1-azido-4-fluo-
robenzene (89 mg, 0.65 mmol), Cu(0) (34 mg, 0.54 mmol) and
22.
Compound 22 was synthesized according to the general
procedure using compound 3 (50 mg, 0.18 mmol) and 4-(azido-
methyl)-7-hydroxycoumarin (48 mg, 0.22 mmol), Cu(0) (14 mg,
0.22 mmol) and 1 M CuSO4 solution (0.04 mL) in a mixture of
tert-BuOH/H2O = 1:1 (5 mL). After purification by column chro-
matography (CH2Cl2/CH3OH = 40:1) compound 22 was isolated as
yellow powder (76 mg, 85%, mp = 139–141 °C). 1H NMR
(600 MHz, DMSO) (d/ppm): 10.65 (s, 1H, OH), 8.12 (s, 2H, H-2, H-
30), 7.89 (d, 1H, J = 1.4 Hz, H-4), 7.62 (d, 1H, J = 8.8 Hz, H-600),
7.30–7.50 (m, 2H, H-6, H-7), 6.67–6.86 (m, 2H, H-900, H-700), 6.33–
6.49 (m, 2H, H-3, H-300), 5.82 (s, 2H, H-40), 5.49 (d, 2H, J = 21.4 Hz,
1 M CuSO4 solution (0.06 mL) in
a mixture of tert-BuOH/
H2O = 1:1 (5 mL). After purification by column chromatography
(CH2Cl2/CH3OH = 120:1) compound 25 was isolated as a powder
(166 mg, 74%, mp = 215–217 °C).1H NMR (300 MHz, DMSO) (d/
ppm): 8.81 (s, 1H, H-80), 7.74–7.91 (m, 5H, H-4, H-7, H-6, H-
20,200), 7.64 (dd, 2H, J H-F = 14.5, J H-H = 8.2 Hz, H-3000), 7.25–7.34 (m,
2H, H-2000), 6.95 (t, 1H, J = 5.7 Hz, NH), 6.80 (d, 2H, J = 8.7 Hz, H-
30,300), 4.49 (d, 2H, J = 5.7 Hz, H-60), 2.42 (s, 3H, CH3). 13C NMR
(151 MHz, DMSO) (d/ppm): 166.81 (C-2), 163.22 (d, J = 243.1 Hz,
C-4000), 162.20 (C-70), 151.97 (C-3a), 150.85 (C-40), 146.36 (C-1000),
133.88 (C-7a), 131.82 (C-80), 128.44 (C-30,300), 127.58 (C-5),
121.50 (C-6), 121.40 (C-10), 120.85 (C-4), 120.77 (C-20,200), 115.83
(d, J = 21.14 Hz, C-2000), 112.24 (C-7), 107.48 (d, J = 27.2 Hz, C-3000),
38.02 (C-60), 20.94 (CH3). MS (ESI): m/z = 416.1 ([M+H]+). Anal.
calcd For C23H18FN5S: C, 66.49; H, 4.37; N, 16.86. Found: C,
66.58; H, 4.38; N, 16.89.
13
H-10). C NMR (151 MHz, DMSO) (d/ppm): 161.59 (C-200), 159.85
(C-800), 155.05 (C-1000), 154.33 (C-400), 143.91 (C-2), 134.65 (C-20),
131.00 (C-3a), 129.73 (C-7a), 129.00 (C-5), 128.81 (C-6), 125.98
(C-600), 124.33 (C-30), 113.12 (C-7), 112.60 (C-700), 109.32 (C-500),
109.25 (C-300), 102.49 (C-900), 100.44 (C-4), 83.02 (C-3), 49.11
(C-40), 40.90 (C-10). MS (ESI): m/z = 500.1 ([M+H]+). Anal. calcd
For C21H17IN4O3: C, 50.42; H, 3.43; N, 11.20. Found: C, 50.36; H,
3.42; N, 11.16.
4.2.3.18.
2-{4-[((1-(2-Fluorophenyl)-1H-1,2,3-triazol-4-yl)
Com-
4.2.3.15. 4-{4-[((5-Iodo-1H-indol-1-yl)methyl)-1H-1,2,3-triazol-
1-yl]methyl}-7-methyl-4a,8a-dihydro-2H-chromen-2-on
methyl]aminophenyl}-6-methylbenzo[d]thiazole 26.
pound 26 was synthesized according to the general procedure
using compound 24 (50 mg, 0.18 mmol) and 1-azido-2-fluoroben-
zene (30 mg, 0.22 mmol), Cu(0) (11 mg, 0.18 mmol) and 1 M CuSO4
solution (0.05 mL) in a mixture of tert-BuOH/H2O = 1:1 (4 mL).
After purification by column chromatography (CH2Cl2/CH3-
OH = 120:1) oily compound 26 was isolated (62 mg, 83%). 1H
NMR (300 MHz, DMSO) d 8.74 (s, 1H, H-80), 7.87–8.05 (m, 2H, H-
5000, H-6000), 7.77–7.81 (m, 5H, H-4, H-6, H-7, H-20,200) 7.78 (dd, 1H,
J H-H = 8.4, J H-F = 4.9 Hz, H-4000), 7.27 (dd, 1H, J H-H = 8.4, J H-
F = 1.4 Hz, H-2000), 6.97 (t, 1H, J = 5.7 Hz, NH), 6.80 (d, 2H,
J = 8.8 Hz, H-30,300), 4.48 (d, 2H, J = 5.6 Hz, H-60), 2.42 (s, 3H, CH3).
13C NMR (151 MHz, DMSO) (d/ppm): 166.82 (C-2), 162.35 (C-4000),
160.72 (C-70), 151.97 (d, J = 164.3 Hz, C-3000), 150.88 (C-3a), 146.18
(C-40), 134.01 (C-7a), 133.94 (d, J = 16.6 Hz, C-1000), 133.20 (d,
23.
Compound 23 was synthesized according to the general
procedure using compound 3 (40 mg, 0.14 mmol) and 4-(azido-
methyl)-7-methylcoumarin (37 mg, 0.17 mmol), Cu(0) (14 mg,
0.22 mmol) and 1 M CuSO4 solution (0.04 mL) in a mixture of
tert-BuOH/H2O = 1:1 (4 mL). After purification by column chro-
matography (CH2Cl2/CH3OH = 70:1) compound 23 was isolated as
yellow powder (73 mg, 78%, mp = 246–247 °C). 1H NMR
(300 MHz, DMSO) (d/ppm): 8.15 (s, 1H, H-30), 7.91 (d, 1H,
J = 1.3 Hz, H-4), 7.65 (d, 1H, J = 8.1 Hz, H-600), 7.22–7.40 (m, 3H,
H-6, H-7, H-2), 7.13–7.27 (m, 2H, H-700, H-900), 6.42 (d, 1H,
J = 3.1 Hz, H-3), 5.88 (s, 2H, H-40), 5.77 (s, 1H, H-300), 5.49 (s, 2H,
H-10), 2.41 (s, 3H, CH3). 13C NMR (75 MHz, DMSO) (d/ppm):
160.01 (C-200), 153.64 (C-400), 150.50 (C-1000), 144.44 (C-800),
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
12
J = 13.6 Hz, C-5000), 132.12 (C-80), 128.43 (C-30,300), 127.58 (C-5),
122.28 (d, J = 9.1 Hz, C-6000), 121.49 (C-6), 121.46 (C-10), 121.40 (C-
4), 120.83 (C-20,200), 116.69 (d, J = 22.7 Hz, C-2000), 112.24 (C-7),
38.04 (C-60), 20.94 (CH3). MS (ESI): m/z = 416.1 ([M+H]+). Anal.
calcd For C23H18FN5S: C, 66.49; H, 4.37; N, 16.86. Found: C,
66.61; H, 4.36; N, 16.83.
151.97 (C-10000), 150.89 (C-10), 150.69 (C-1000), 145.60 (C-40),
133.99 (C-6), 133.89 (C-7a), 128,41 (C-20,200), 127.57 (C-7000),
126.04 (C-5), 124.04 (C-70), 121.49 (C-6000), 121.40 (C-9000), 120.77
(C-4, C-7), 113.13 (C-3000), 112.21 (C-80), 109.36 (C-30,300), 109.05
(C-5000), 102.48 (C-4000), 49.09 (C-60), 38.05 (C-90), 20.94 (CH3). MS
(ESI): m/z = 498.2 ([M+H]+). Anal. calcd For C27H23N5O3S: C,
65.17; H, 4.66; N, 14.08. Found: C, 65.15; H, 4.67; N, 14.11.
4.2.3.19.
2-{4-[((1-(3,5-Dichlorophenyl)-1H-1,2,3-triazol-4-yl)
Com-
methyl]aminophenyl}-6-methylbenzo[d]thiazole 27.
4.2.3.22. 4-{[4-((4-(6-Methylbenzo[d]thiazol-2-yl)phenylamino)
methyl)-1H-1,2,3-triazol-1-yl]methyl}-7-methyl-4a,8a-dihydro-
pound 27 was synthesized according to the general procedure
using compound 24 (50 mg, 0.18 mmol) and 1-azido-3,5-
dichlorobenzene (41 mg, 0.22 mmol), Cu(0) (11 mg, 0.18 mmol)
and 1 M CuSO4 solution (0.05 mL) in a mixture of tert-BuOH/
H2O = 1:1 (4 mL). After purification by column chromatography
(CH2Cl2/CH3OH = 120:1) oily compound 27 was isolated (70 mg,
2H-chromen-2-on 30.
Compound 30 was synthesized
according to the general procedure using compound 24 (50 mg,
0.18 mmol) and 4-(azidomethyl)-7-methylcoumarin (47 mg,
0.22 mmol), Cu(0) (11 mg, 0.18 mmol) and 1 M CuSO4 solution
(0.05 mL) in
a mixture of tert-BuOH/H2O = 1:1 (4 mL). After
1
84%). H NMR (300 MHz, DMSO) d 8.90 (s, 1H, H-80), 8.08 (d, 2H,
purification by column chromatography (CH2Cl2/CH3OH = 50:1)
J = 1.7 Hz, H-2000), 7.71–7.87 (m, 5H, H-4, H-7, H-20,200, H-4000), 7.27
(d, J = 8.3 Hz, 1H, H-6), 7.01 (t, 1H, J = 5.7 Hz, NH), 6.79 (d, 2H,
J = 8.7 Hz, H-30,300), 4.50 (d, J = 5.7 Hz, 2H, H-60), 2.42 (s, 3H, CH3).
13C NMR (75 MHz, DMSO) (d/ppm): 167.31 (C-2), 160.34 (C-70),
152.44 (C-1000), 151.29 (C-3a), 147.16 (C-40), 138.70 (C-1000), 135.73
(C-80), 134.52 (C-7a), 134.36 (C-4), 128.95 (C-30,300), 128.39 (C-
3000), 122.07 (C-6), 122.00 (C-10), 121.90 (C-5), 121.34 (C-20,200),
119.01 (C-2000), 112.72 (C-7), 38.46 (C-60), 21.44 (CH3). MS (ESI):
m/z = 466.1 ([M+H]+). Anal. calcd For C23H17Cl2N5S: C, 59.23; H,
3.67; N, 15.02. Found: C, 59.49; H, 3.68; N, 15.05.
compound 30 was isolated as yellow powder (63 mg, 71%,
1
mp = 263–265 °C). H NMR (300 MHz, DMSO) d: 8.17 (s, 1H, H-80),
7.62–7.88 (m, 3H, H-4,, H-6000, H-9000), 7.18–7.30 (m, 5H, H-6, H-7,
H-20,200, H-7000), 6.92 (s, 1H, NH), 6.75 (s, 1H, H-3000), 5.93 (s, 2H,
H-60), 5.77 (d, 2H, J = 8.3 Hz, H-30,300), 4.44 (s, 2H, H-90), 3.33 (s,
3H, CH3), 2.41 (s, 3H, CH3). 13C NMR (151 MHz, DMSO) (d/ppm):
166.81 (C-2000), 159.53 (C-2), 153.14 (C-8000), 151.90 (C-3a), 150.89
(C-10000), 150.20 (C-10), 145.62 (C-1000), 143.51 (C-40), 133.94 (C-
7a), 128.42 (C-6), 127.65 (C-20,200), 125.65 (C-7000), 124.40 (C-5),
121.57 (C-70), 121.46 (C-6000), 120.73 (C-9000), 116.81 (C-4), 116.75
(C-7), 114.69 (C-3000), 112.63 (C-80), 112.20 (C-30,300), 107.32 (C-
5000), 102.52 (C-4000) 49.03 (C-60), 38.05 (C-90), 21.01 (CH3), 20.91
(CH3). MS (ESI): m/z = 496.2 ([M+H]+). Anal. calcd For C28H25N5O2-
S: C, 67.86; H, 5.08; N, 14.13. Found: C, 67.77; H, 5.07; N, 14.12.
4.2.3.20.
2-{4-[((1-(4-Chlorophenyl)-1H-1,2,3-triazol-4-yl)
Com-
methyl]aminophenyl}-6-methylbenzo[d]thiazole 28.
pound 28 was synthesized according to the general procedure
using compound 24 (50 mg, 0.18 mmol) and 1-azido-4-chloroben-
zene (34 mg, 0.22 mmol), Cu(0) (11 mg, 0.18 mmol) and 1 M CuSO4
solution (0.05 mL) in a mixture of tert-BuOH/H2O = 1:1 (4 mL).
After purification by column chromatography (CH2Cl2/CH3
OH = 120:1) oily compound 28 was isolated (62 mg, 80%). 1H
NMR (300 MHz, DMSO) (d/ppm): 8.79 (s, 1H, H-80), 7.94 (d, 2H,
J = 9.4 Hz, H-3000), 7.75– 7.84 (m, 4H, H-4, H-7, H-20,200), 7.68 (d,
2H J = 8.4 Hz, H-2000), 7.27 (d, 1H, J = 8.4 Hz, H-6), 6.97 (t, 1H,
J = 5.7 Hz, NH), 6.80 (d, 2H, J = 8.8 Hz, H-30,300), 4.48 (d, 2H,
J = 5.6 Hz, H-60), 2.42 (s, 3H, CH3). 13C NMR (75 MHz, DMSO) (d/
ppm): 167.32 (C-2), 158.29 (C-70), 152.45 (C-4000), 151.35 (C-3a),
146.84 (C-1000), 140.63 (C-40), 135.91 (C-7a), 134.50 (C-80), 134.37
(C-30,300), 130.34 (C-5), 128.94 (C-3000), 128.09 (C-6), 122.11 (C-10),
122.01 (C-4), 121.90 (C-20,200), 121.31 (C-2000), 112.73 (C-7), 38.50
(C-60), 21.45 (CH3). MS (ESI): m/z = 432.1 ([M+H]+). Anal. calcd
For C23H18ClN5S: C, 63.95; H, 4.20; N, 16.21. Found: C, 63.90; H,
4.21; N, 16.22.
4.2.4. General procedure for the synthesis of N-alkylated 1,2,3-
triazoles 31a,b–34a
Triazole derivative (5–8) was dissolved in DMF and K2CO3
(1 equiv) was added. The mixture was stirred for 30 min and 2-ace-
toxymethyl-4-iodobutyl acetate (1 equiv)57 was added. The stir-
ring continued overnight at room temperature. The precipitate
was filtered off, the solvents removed under reduced pressure
and the residue purified by column chromatography.
4.2.4.1. 1-{[2-(4-Acetoxy-3-(acetoxymethyl)butyl)-1H-1,2,3-tria-
zol-4-yl]methyl}-1H-benzo[d]imidazole 31a and 1-{[1-(4-ace-
toxy-3-(acetoxymethyl)butyl)-1H-1,2,3-triazol-4-yl]methyl}-
1H-benzo[d]imidazole 31b.
According to the general proce-
dure using compound 5 (200 mg, 1.0 mmol). After purification by
column chromatography (CH2Cl2/CH3OH = 15:1) compounds 31a
(298 mg, 77%) and 31b (95 mg, 25%) were isolated as yellow oils.
31a: 1H NMR (300 MHz, DMSO) (d/ppm): 8.31 (s, 1H, H-2), 7.78
(s, 1H, H-30), 7.56–7.66 (m, 2H, H-4, H-7), 7.15–7.26 (m, 2H, H-5, H-
6), 5.57 (s, 2H, H-10), 4.45 (t, 2H, J = 6.7 Hz, H-40), 3.91–4.03 (m, 4H,
2ꢁH-70), 1.98 (s, 6H, 2ꢁCOCH3), 1.83–1.93 (m, 3H, H-50, H-60). 13C
NMR (151 MHz, DMSO) (d/ppm): 170.19 (COCH3), 143.87 (C-2),
143.44 (C-20), 143.33 (C-3a), 133.49 (C-7a), 133.20 (C-30), 122.38
(C-5), 121.64 (C-6), 119.39 (C-4), 110.51 (C-7), 63.24 (C-70), 51.96
(C-40), 34.36 (C-60), in DMSO (C-10), 27.90 (C-50), 20.51 (COCH3).
MS (ESI): m/z = 386.2 ([M+H]+). Anal. calcd For C19H23N5O4: C,
59.21; H, 6.01; N, 18.17. Found: C, 59.15; H, 6.02; N, 18.21.
31b: 1H NMR (300 MHz, DMSO) (d/ppm): 8.31 (s, 1H, H-2), 8.15
(s, 1H, H-30), 7.54–7.71 (m, 2H, H-4, H-7), 7.17–7.26 (m, 2H, H-5, H-
6), 5.56 (s, 2H, H-10), 4.41 (t, 2H, J = 7.1 Hz, H-40), 3.99 (d, 4H,
J = 4.8 Hz, 2ꢁH-70), 1.98 (s, 6H, 2ꢁCOCH3), 1.80–1.92 (m, 3H, H-
50, H-60). 13C NMR (151 MHz, DMSO) (d/ppm): 170.29 (COCH3),
143.81 (C-2), 142.46 (C-20), 140.53 (C-3a), 133.43 (C-7a), 123.53
(C-30), 122.41 (C-5), 121.69 (C-6), 119.28 (C-4), 110.68 (C-7),
4.2.3.21. 4-{[4-((4-(6-Methylbenzo[d]thiazol-2-yl)phenylamino)
methyl)-1H-1,2,3-triazol-1-yl]methyl}-7-hydroxy-4a,8a-dihy-
dro-2H-chromen-2-on 29.
Compound 29 was synthesized
according to the general procedure using compound 24 (50 mg,
0.18 mmol) and 4-(azidomethyl)-7-hydroxycoumarin (48 mg,
0.22 mmol), Cu(0) (11 mg, 0.18 mmol) and 1 M CuSO4 solution
(0.05 mL) in a mixture of tert-BuOH/H2O = 1:1 (4 mL). After purifi-
cation by column chromatography (CH2Cl2/CH3OH = 50:1) com-
pound 29 was isolated as yellow powder (60 mg, 68%, mp = 229–
231 °C). 1H NMR (600 MHz, DMSO) (d/ppm): 10.68 (s, 1H, OH),
8.16 (s, 1H, H-80), 7.76–7.88 (m, 3H, H-4, H-6000, H-9000), 7.70 (d,
1H, J = 8.8 Hz, H-6), 7.28 (d, 1H, J = 8.3 Hz, H-7), 6.91 (t, 1H,
J = 5.8 Hz, NH), 6.83 (d, 1H, J = 8.8 Hz, H-7000), 6.73–6.81 (m, 4H,
H-20,200, H-30,300), 5.89 (s, 2H, H-60), 6.76 (s, 1H, H-3000), 4.45 (d, 2H,
J = 5.7 Hz, H-90), 2.43 (s, 3H, CH3). 13C NMR (151 MHz, DMSO) (d/
ppm): 166.84 (C-2000), 161.59 (C-2), 159.90 (C-8000), 155.04 (C-3a),
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
63.30 (C-70), 47.17 (C-40), 34.33 (C-60), in DMSO (C-10), 28.57 (C-50),
4.2.4.4. 1-{2[-4-Acetoxy-3-(acetoxymethyl)butyl)-1H-1,2,3-tria-
zol-4-yl]methyl}-5-fluoro-1H-indole 34a. According to the
20.52 (COCH3). MS (ESI): m/z = 386.2 ([M+H]+). Anal. calcd For
C
19H23N5O4: C, 59.21; H, 6.01; N, 18.17. Found: C, 59.10; H, 6.03;
general procedure using compound 8 (101 mg, 0.47 mmol). After
purification by column chromatography (n-hexane/ethyl-acet-
ate = 1:1) compound 34a (126 mg, 66%) was isolated as colourless
oil. 1H NMR (600 MHz, DMSO) (d/ppm): 7.64 (s, 1H, H-30), 7.52 (dd,
1H, J = 8.9 Hz, JH-F = 4.5 Hz, H-4), 7.49 (d, 1H, J = 3.1 Hz, H-2), 7.29
N, 18.15.
4.2.4.2. 1-{2[-4-(Acetoxy-3-(acetoxymethyl)butyl)-1H-1,2,3-tria-
zol-4-yl]methyl}-2-methyl-1H-benzo[d]imidazole 32a and 1-
{[1-(4-acetoxy-3-(acetoxymethyl)butyl)-1H-1,2,3-triazol-4-yl]
(dd, 1H, J = 2.5 Hz, JH-F = 9.9 Hz, H-7), 6.96 (td, 1H, J = 2.5 Hz, JH-F
=
methyl}-2-methyl-1H-benzo[d]imidazole 32b.
According to
9.2 Hz, H-6), 6.44 (dd, 1H, J = 3.2 Hz, JH-F = 0.7 Hz, H-3), 5.46 (s,
2H, H-10), 4.45 (t, 2H, J = 6.8 Hz, H-40), 3.94–4.01 (m, 4H, H-70),
1.98 (s, 6H, 2ꢁCOCH3), 1.86–1.90 (m, 3H, H-60, H-50). 13C NMR
the general procedure using compound 6 (80 mg, 0.38 mmol).
After purification by column chromatography (CH2Cl2/CH3
OH = 15:1) compounds 32a (129 mg, 84%) and 32b (28 mg, 19%)
were isolated as colourless oils.
(75 MHz, DMSO) (d/ppm): 170.24 (COCH3), 157.09 (JC-F
=
231.8 Hz, C-5), 144.30 (C-20), 134.83 (C-7a), 132.96 (C-30), 128.49
(JC-F = 10.3 Hz, C-3a), 130.52 (C-2), 109.18 (JC-F = 25.5 Hz, C-6),
110.91 (JC-F = 9.8 Hz, C-7), 105.00 (C-4, JC-F = 23.3 Hz), 101.15 (JC-
F = 4.5 Hz, C-3), 63.23 (C-70), 51.87 (C-40), 40.75 (C-10), 34.33 (C-
60), 27.90 (C-50), 20.52 (COCH3). MS (ESI): m/z = 403.2 ([M+H]+).
Anal. calcd For C20H23FN4O4: C, 59.69; H, 5.76; N, 13.92. Found:
C, 59.76; H, 5.78; N, 13.89.
32a: 1H NMR (600 MHz, DMSO) (d/ppm): 7.75 (s, 1H, H-30), 7.54
(d, 1H, J = 7.6 Hz, H-7), 7.50 (d, 1H, J = 7.5 Hz, H-4), 7.12–7.17 (m,
2H, H-5, H-6), 5.48 (s, 2H, H-10), 4.44 (t, 2H, J = 6.7 Hz, H-40),
3.93–4.00 (m, 4H, 2ꢁH-70), 2.60 (s, 3H, CH3), 1.97 (s, 6H, 2ꢁCOCH3),
1.86–1.88 (m, 3H, H-60, H-50). 13C NMR (151 MHz, DMSO) (d/ppm):
170.18 (COCH3), 151.62 (C-2), 143.57 (C-20), 142.28 (C-3a), 134.91
(C-7a), 132.96 (C-30), 121.48 (C-5), 121.27 (C-6), 118.18 (C-4),
109.81 (C-7), 63.23 (C-70), 51.92 (C-40), 38.00 (C-10), 34.35 (C-60),
27.87 (C-50), 20.50 (COCH3), 13.57 (CH3). MS (ESI): m/z = 400.2
([M+H]+). Anal. calcd For C20H25N5O4: C, 60.14; H, 6.31; N, 17.53.
Found: C, 60.05; H, 6.32; N, 17.59.
4.2.5. General procedure for the synthesis of compounds 35a,b–
38a
Dry triazole derivative (31a,b–34a) was dissolved in anhydrous
CH3OH and freshly prepared 0.1 M NaOCH3 solution in CH3OH was
added. After stirring for 4 h at room temperature, the mixture was
neutralized with HCl/CH3OH. Solvent was evaporated and residue
purified by column chromatography.
32b: 1H NMR (600 MHz, DMSO) (d/ppm): 8.12 (s, 1H, H-30), 7.55
(d, 1H, J = 7.8 Hz, H-7), 7.48 (d, 1H, J = 7.5 Hz, H-4), 7.08–7.17 (m,
2H, H-5, H-6), 5.45 (s, 2H, H-10), 4.37 (t, 2H, J = 7.3 Hz, H-40),
3.90–4.02 (m, 4H, 2ꢁH-70), 2.61 (s, 3H, CH3), 1.95 (s, 6H, 2ꢁCOCH3),
1.85–1.90 (m, 1H, H-60), 1.80–1.84 (m, 2H, H-50). 13C NMR
(151 MHz, DMSO) (d/ppm): 170.22 (COCH3), 151.63 (C-2), 142.66
(C-20), 142.29 (C-3a), 134.89 (C-7a), 123.21 (C-30), 121.41 (C-5),
121.20 (C-6), 118.13 (C-4), 109.91 (C-7), 63.32 (C-70), 47.15 (C-
40), 38.22 (C-10), 34.38 (C-60), 28.60 (C-50), 20.52 (COCH3), 13.65
(CH3). MS (ESI): m/z = 400.2 ([M+H]+). Anal. calcd For
4.2.5.1. 1-{[2-(4-(Hydroxy-3-(hydroxymethyl)butyl)-1H-1,2,3-
triazol-4-yl]methyl}-1H-benzo[d]imidazole 35a.
According
to the general procedure using compound 31a (290 mg,
0.75 mmol) and 0.1 M NaOCH3/CH3OH (0.75 mL) compound 35a
(211 mg, 93%) was isolated after purification by column chro-
matography (CH2Cl2/CH3OH = 10:1) as yellow oil. 1H NMR
(300 MHz, DMSO) (d/ppm): 8.31 (s, 1H, H-2), 7.74 (s, 1H, H-30),
7.56–7.66 (m, 2H, H-4, H-7), 7.15–7.27 (m, 2H, H-5, H-6), 5.56 (s,
2H, H-10), 4.34–4.45 (m, 4H, H-40, 2ꢁOH), 3.32–4.43 (m, 4H, H-
70), 1.77–1.85 (m, 2H, H-50), 1.40–1.48 (m, 1H, H-60). 13C NMR
(75 MHz, DMSO) (d/ppm): 143.88 (C-2), 143.76 (C-20), 143.69 (C-
3a), 134.02 (C-7a), 133.46 (C-30), 122.90 (C-5), 122.11 (C-6),
119.93 (C-4), 111.02 (C-7), 61.59 (C-70), 53.27 (C-40), 40.90 (C-60),
39.63 (C-10), 28.81 (C-50). MS (ESI): m/z = 302.2 ([M+H]+). Anal.
calcd For C15H19N5O2: C, 59.79; H, 6.36; N, 23.24. Found: C,
59.87; H, 6.34; N, 23.14.
C20H25N5O4: C, 60.14; H, 6.31; N, 17.53. Found: C, 60.02; H, 6.32;
N, 17.55.
4.2.4.3. 1-{[2-(4-Acetoxy-3-(acetoxymethyl)butyl)-1H-1,2,3-tria-
zol-4-yl]methyl}-5-iodo-1H-indole 33a and 1-{[1-(4-acetoxy-3-
(acetoxymethyl)butyl)-1H-1,2,3-triazol-4-yl]methyl}-5-iodo-
1H-indole 33b.
According to the general procedure using
compound 7 (123 mg, 0.38 mmol). After purification by column
chromatography (ethyl acetate) compounds 33a (51 mg, 26%)
and 33b (23 mg, 3%) were isolated as yellow oil.
33a: 1H NMR (300 MHz, DMSO) (d/ppm): 7.91 (s, 1H, H-2), 7.64
(s, 1H, H-30), 7.43 (d, 1H, J = 3.2 Hz, H-4), 7.34–7.42 (m, 2H, H-6, H-
7), 6.42 (d, 1H, J = 3.1 Hz, H-3), 5.45 (s, 2H, H-10), 4.44 (t, 2H,
J = 6.6 Hz, H-40), 3.91–4.04 (m, 4H, H-70), 1.98 (s, 6H, 2ꢁCOCH3),
1.86–1.94 (m, 3H, H-60, H-50). 13C NMR (75 MHz, DMSO) (d/ppm):
170.70 (COCH3), 144.68 (C-20), 135.19 (C-7a), 133.43 (C-4),
131.49 (C-3a), 130.23 (C-2), 129.53 (C-6), 129.32 (C-30), 113.02
(C-7), 101.01 (C-3), 83.54 (C-5), 63.74 (C-70), 52.38 (C-40), 41.14
(C-10), 34.85 (C-60), 28.40 (C-50), 21.04 (COCH3). MS (ESI): m/
z = 511.1 ([M+H]+). Anal. calcd For C20H23IN4O4: C, 47.07; H, 4.54;
N, 10.98. Found: C, 46.98; H, 4.55; N, 10.95.
4.2.5.2. 1-{[1-(4-Hydroxy-3-(hydroxymethyl)butyl)-1H-1,2,3-tri-
azol-4-yl]methyl}-1H-benzo[d]imidazole 35b.
According to
the general procedure using compound 31b (90 mg, 0.23 mmol)
and 0.1 M NaOCH3/CH3OH (0.23 mL) compound 35b (61 mg, 86%)
was isolated after purification by column chromatography (CH2Cl2/
CH3OH = 10:1) as colourless oil. 1H NMR (300 MHz, DMSO) (d/
ppm): 8.31 (s, 1H, H-2), 7.60–7.67 (m, 2H, H-4, H-7), 7.27–7.38
(m, 2H, H-5, H-6), 5.55 (s, 2H, H-10), 8.14 (s, 1H, H-30), 4.40–4.50
(m, 4H, H-40, 2ꢁOH), 3.32–4.43 (m, 4H, H-70), 1.72–1.79 (m, 2H,
H-50), 1.39–1.47 (m, 1H, H-60). 13C NMR (75 MHz, DMSO) (d/
ppm): 143.90 (C-2), 142.87 (C-20), 140.44 (C-3a), 134.02 (C-7a),
123.81 (C-30), 122.81 (C-5), 122.05 (C-6), 119.86 (C-4), 111.15 (C-
7), in DMSO (C-10), 61.64 (C-70), 48.39 (C-40), 41.00 (C-60), 29.53
(C-50). MS (ESI): m/z = 302.2 ([M+H]+). Anal. calcd For
C15H19N5O2: C, 59.79; H, 6.36; N, 23.24. Found: C, 59.84; H, 6.34;
N, 23.15.
33b: 1H NMR (300 MHz, DMSO) (d/ppm): 8.02 (s, 1H, H-30), 7.91
(s, 1H, H-2), 7.35–7.46 (m, 3H, H-4, H-6, H-7), 6.41 (d, 1H,
J = 2.7 Hz, H-3), 5.44 (s, 2H, H-10), 4.39 (t, 2H, J = 7.3 Hz, H-40),
3.98 (d, 4H, J = 4.6 Hz, H-70), 1.98 (s, 6H, 2ꢁCOCH3), 1.79–1.89 (m,
3H, H-60, H-50). 13C NMR (151 MHz, DMSO) (d/ppm): 170.21
(COCH3), 143.27 (C-20), 134.66 (C-7a), 131.00 (C-3a), 129.68 (C-
4), 128.97 (C-2), 128.77 (C-6), 123.11 (C-30), 112.62 (C-7), 100.34
(C-3), 82.93 (C-5), 63.33 (C-70), 47.11 (C-40), 40.97 (C-10), 34.41
(C-60), 28.64 (C-50), 20.53 (COCH3). MS (ESI): m/z = 511.1 ([M
+H]+). Anal. calcd For C20H23IN4O4: C, 47.07; H, 4.54; N, 10.98.
Found: C, 47.01; H, 4.55; N, 10.95.
4.2.5.3. 1-{[2-(4-Hydroxy-3-(hydroxymethyl)butyl)-1H-1,2,3-tri-
azol-4-yl]methyl}-2-methyl-1H-benzo[d]imidazole
36a.
According to the general procedure using compound 32a
(112 mg, 0.28 mmol) and 0.1 M NaOCH3/CH3OH (0.28 mL)
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S. Maracic et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
14
compound 36a (54 mg, 61%) was isolated after purification by col-
umn chromatography (CH2Cl2/CH3OH = 7:1) as colourless oil. 1H
NMR (300 MHz, DMSO) (d/ppm): 7.72 (s, 1H, H-30), 7.48–7.57 (m,
2H, H-4, H-7), 7.09–7.20 (m, 2H, H-5, H-6), 5.48 (s, 2H, H-10),
4.36–4.42 (m, 4H, H-40, 2ꢁOH), 3.30–3.45 (m, 4H, H-70), 2.60 (s,
3H, CH3), 1.76–1.83 (m, 2H, H-50), 1.38–1.47 (m, 1H, H-60). 13C
NMR (75 MHz, DMSO) (d/ppm): 150.02 (C-2), 143.80 (C-20),
143.72 (C-3a), 133.69 (C-7a), 133.22 (C-30), 122.02 (C-5), 121.77
(C-6), 118.68 (C-4), 110.34 (C-7), 61.58 (C-70), 53.25 (C-40), 40.93
(C-60), 38.51 (C-10), 28.79 (C-50), 14.11 (C-CH3). MS (ESI): m/
z = 316.2 ([M+H]+). Anal. calcd For C16H21N5O2: C, 60.94; H, 6.71;
N, 22.21. Found: C, 60.88; H, 6.70; N, 22.24.
and 0.1 M NaOCH3/CH3OH (3.1 mL) compound 38a (26 mg, 26%)
was isolated after purification by column chromatography (n-hex-
ane/ethyl acetate = 10:1) as colourless oil. 1H NMR (300 MHz,
DMSO) (d/ppm): 7.62 (s, 1H, H-30), 7.48–7.55 (m, 2H, H-4, H-2),
7.29 (dd, 1H, J = 9.9 Hz, JH-F = 2.5 Hz, H-7), 6.97 (td, 1H, J = 9.3 Hz,
JH-F = 2.5 Hz, H-6), 6.44 (d, 1H, J = 3.1 Hz, H-3), 5.45 (s, 2H, H-10),
4.40 (t, 4H, J = 7.7 Hz, H-40, 2ꢁOH), 3.32–3.44 (m, 4H, H-70), 1.77–
1.84 (m, 2H, H-50), 1.40–1.48 (m, 1H, H-60). 13C NMR (151 MHz,
DMSO) (d/ppm): 157.10 (JC-F = 231.10 Hz, C-5), 144.03 (C-20),
132.71 (C-30), 132.31 (C-7a), 130.52 (C-2), 128.46 (JC-F = 10.1 Hz,
C-3a), 109.27 (JC-F = 26.0 Hz, C-6), 110.99 (JC-F = 9.7 Hz, C-7),
104.99 (JC-F = 23.1 Hz, C-4), 101.17 (JC-F = 4.6 Hz, C-3), 61.07 (C-
70), 52.68 (C-40), 40.77 (C-10), 40.39 (C-60), 28.32 (C-50). MS (ESI):
m/z = 319.2 ([M+H]+). Anal. calcd For C16H19FN4O2: C, 60.37; H,
6.02; N, 17.60. Found: C, 60.29; H, 6.00; N, 17.54.
4.2.5.4. 1-{[1-(4-Hydroxy-3-(hydroxymethyl)butyl)-1H-1,2,3-tri-
azol-4-yl]methyl}-2-methyl-1H-benzo[d]imidazole
36b.
According to the general procedure using compound 32b
(29 mg, 0.07 mmol) and 0.1 M NaOCH3/CH3OH (0.07 mL) com-
pound 36b (10 mg, 43%) was isolated after purification by column
chromatography (CH2Cl2/CH3OH = 7:1) as colourless oil. 1H NMR
(300 MHz, DMSO) (d/ppm): 8.13 (s, 1H, H-30), 7.45–7.61 (m, 2H,
H-4, H-7), 7.12–7.19 (m, 2H, H-5, H-6), 5.46 (s, 2H, H-10), 4.30–
4.49 (m, 4H, H-40, 2ꢁOH), 3.31–3.45 (m, 4H, H-70), 2.64 (s, 3H,
CH3), 1.72–1.79 (m, 2H, H-50), 1.39–1.51 (m, 1H, H-60). 13C NMR
(75 MHz, DMSO) (d/ppm): 150.89 (C-2), 143.02 (C-20), 142.77 (C-
3a), 133.69 (C-7a), 123.53 (C-30), 121.93 (C-5), 121.70 (C-6),
118.62 (C-4), 110.45 (C-7), 61.64 (C-70), 48.39 (C-40), 41.03 (C-60),
38.71 (C-10), 29.52 (C-50), 14.17 (C-CH3). MS (ESI): m/z = 316.2
([M+H]+). Anal. calcd For C16H21N5O2: C, 60.94; H, 6.71; N, 22.21.
Found: C, 60.85; H, 6.69; N, 22.25.
4.3. Crystal structure determination
Single crystal of 5 suitable for X-ray single crystal analysis was
obtained at room temperature by partial evaporation from metha-
nol solution. The intensities were collected at 295 K on Oxford
Diffraction Xcalibur2 diffractometer with a Sapphire 3 CCD detector
using graphite-monochromated MoK radiation (k = 0.71073 Å).
a
The CrysAlisPro58 program was used for the data collection and
processing. The intensities were corrected for absorption using
the multi-scan absorption correction method.58 The structure was
solved by direct methods with SHELXS-201459 and refined by
full-matrix least-squares calculations based on F2 using
SHELXL-201459 integrated in the WinGX60 program package.
Hydrogen atoms attached to the nitrogen N3 atom and the water
oxygen O1 atom have been found in Fourier map and refined freely.
All other hydrogen atoms were included in calculated positions as
riding atoms, with SHELXL-201459 defaults. The PLATON61 and
Mercury62 programs were used for structure analysis and molecular
and crystal structure drawings preparation. The CCDC 1413022
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
4.2.5.5. 1-{[2-(4-Hydroxy-3-(hydroxymethyl)butyl)-1H-1,2,3-tri-
azol-4-yl]methyl}-5-iodo-1H-indole 37a.
According to the
general procedure using compound 33a (51 mg, 0.1 mmol) and
0.1 M NaOCH3/CH3OH (0.1 mL) compound 37a (19 mg, 45%) was
isolated after purification by column chromatography (CH2Cl2/
CH3OH = 15:1) as off yellow oil. 1H NMR (300 MHz, DMSO) (d/
ppm): 7.91 (s, 1H, H-2), 7.61 (s, 1H, H-30), 7.43 (d, 1H, J = 3.2 Hz,
H-4), 7.39 (s, 2H, H-6, H-7), 6.42 (d, 1H, J = 3.1 Hz, H-3), 5.45 (s,
2H, H-10), 4.37–4.42 (m, 4H, H-40, 2ꢁOH), 3.30–3.45 (m, 4H, H-
70), 1.77–1.84 (m, 2H, H-50), 1.40–1.48 (m, 1H, H-60). 13C NMR
(75 MHz, DMSO) (d/ppm): 143.91 (C-20), 134.71 (C-7a), 132.67
(C-4), 130.98 (C-3a), 129.72 (C-2), 129.06 (C-6), 128.82 (C-30),
112.52 (C-7), 100.51 (C-3), 83.01 (C-5), 61.14 (C-70), 52.72 (C-40),
40.67 (C-10), 40.45 (C-60), 28.35 (C-50). MS (ESI): m/z = 427.1 ([M
+H]+). Anal. calcd For C16H19IN4O2: C, 45.08; H, 4.49; N, 13.14.
Found: C, 45.01; H, 4.50; N, 13.16.
Crystal data for 5: 0.51 ꢁ 0.28 ꢁ 0.13 mm3; C10H11N5O,
Mr = 217.24, monoclinic space group P21/n; a = 10.5637(5) Å,
b = 10.4866(3) Å, c = 10.6998(5) Å, b = 115.796(6)°, V = 1067.18
(9) Å3, Z = 4;
q , l
= 1.352 g cmꢂ3 = 0.095 mmꢂ1; 11006 reflections
(hmax = 26.999°) measured (2327 unique reflections, 1983 with
I P 2 (I), RInt = 0.0220, completeness = 99.7%); R indices [(I > 2
r
r
(I)]: R1 = 0.0359, wR2 = 0.0946, R indices [all data]: R1 = 0.0436,
wR2 = 0.1010, S = 1.032 for 157 parameters and 0 restraints, largest
4.2.5.6. 1-{[1-4-Hydroxy-3-(hydroxymethyl)butyl)-1H-1,2,3-tri-
diff. peak and hole 0.149/ꢂ0.161 eÅꢂ3
.
azol-4-yl]methyl}-5-iodo-1H-indole 37b.
According to the
general procedure using compound 33b (23 mg; 0.05 mmol) and
0.1 M NaOCH3/CH3OH (0.05 mL) compound 37b (11 mg, 53%)
was isolated after purification by column chromatography (CH2Cl2/
CH3OH = 15:1) as off yellow oil. 1H NMR (300 MHz, DMSO) (d/
ppm): 8.00 (s, 1H, H-30), 7.90 (s, 1H, H-2), 7.29–7.53 (m, 3H, H-4,
H-6, H-7), 6.41 (d, 1H, J = 2.8 Hz, H-3), 5.43 (s, 2H, H-10), 4.29–
4.45 (m, 4H, H-40, 2ꢁOH), 3.32–3.45 (m, 4H, H-70), 1.71–1.78 (m,
2H, H-50), 1.39–1.49 (m, 1H, H-60). 13C NMR (151 MHz, DMSO)
(d/ppm): 143.13 (C-20), 134.63 (C-7a), 130.96 (C-3a), 129.68
(C-4), 128.96 (C-2), 128.75 (C-6), 122.95 (C-30), 112.65 (C-7),
100.32 (C-3), 82.97 (C-5), 61.11 (C-70), 47.82 (C-40), 40.92 (C-10),
40.50 (C-60), 29.04 (C-50). MS (ESI): m/z = 427.1 ([M+H]+). Anal.
calcd For C16H19IN4O2: C, 45.08; H, 4.49; N, 13.14. Found: C,
45.15; H, 4.50; N, 13.10.
4.4. Spectroscopic characterization
UV/Vis absorption spectra of compounds 18–23 and 25–30
were recorded at the concentration of 2 ꢁ 10ꢂ5 moldmꢂ3 and were
undertaken in methanol. Fluorescence emission spectra of com-
pounds 18–23 (1 ꢁ 10ꢂ6 moldmꢂ3
) and 25–30 in methanol
(1 ꢁ 10ꢂ7 moldmꢂ3) were measured at an excitation wavelength
of each molecule at their corresponding absorption band.
UV absorption spectra were recorded, against the solvent, at
(25 0.1) °C, using a Varian Cary 50 spectrophotometer operated
in double-beam mode. The wavelength range covered was 200–
450 nm. Quartz cells of 1-cm path length were used throughout
and absorbancies were sampled at 0.1 nm intervals. Fluorescence
measurements were carried out on a Varian Cary Eclipse fluores-
cence spectrophotometer at 25 °C using 1-cm path quartz cells.
Excitation maxima were determined from excitation spectra
covering the range of 200–450 nm. Emission spectra were recorded
4.2.5.7.
1H-1,2,3-triazol-4-yl]methyl})-1H-indole 38a.
the general procedure using compound 34a (126 mg, 0.31 mmol)
5-fluoro-1-{[2-(4-Hydroxy-3-(hydroxymethyl)butyl)-
According to
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Please cite this article in press as: Maracic, S.; et al. Bioorg. Med. Chem. (2015), http://dx.doi.org/10.1016/j.bmc.2015.10.042

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