Structure-activity relationships of tetrahydrocarbazole derivatives as antifungal lead compounds

Article abstract of DOI:10.1039/c2md20211e

A Saccharomyces cerevisiae N-myristoyltransferase (NMT) inhibitor bearing a tetrahydrocarbazole scaffold was found to possess broad-spectrum antifungal activity. A series of C6- and N9-modified tetrahydrocarbazole derivatives were designed and synthesized

Full text of DOI:10.1039/c2md20211e

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Structure–activity relationships of tetrahydrocarbazole
derivatives as antifungal lead compounds
Cite this: DOI: 10.1039/c2md20211e
a
c
Wenya Wang,†ab Guoqiang Dong,† Julin Gu, Yongqiang Zhang,a
*
Shengzheng Wang,a Shiping Zhu,a Yang Liu,a Zhenyuan Miao,a Jianzhong Yao,a
Wannian Zhang and Chunquan Sheng
a
a
*
*
A Saccharomyces cerevisiae N-myristoyltransferase (NMT) inhibitor bearing a tetrahydrocarbazole scaffold
was found to possess broad-spectrum antifungal activity. series of C6- and N9-modified
tetrahydrocarbazole derivatives were designed and synthesized. An in vitro antifungal assay indicated
that several tetrahydrocarbazole derivatives showed improved activity with broad spectrum.
A
Received 25th July 2012
a
Accepted 7th November 2012
Particularly, the inhibitory activity of compound 10c against Cryptococcus neoformans, Aspergillus
fumigatus and M. gypseum was comparable or superior to that of fluconazole and benzofuran NMT
inhibitors. The present study provides a good starting point for the discovery of novel antifungal agents.
DOI: 10.1039/c2md20211e
www.rsc.org/medchemcomm
develop novel antifungal drugs with new chemotypes and new
modes of action.
Introduction
Recently, the incidence of systemic fungal infections and
associated mortality has been increasing dramatically.1,2 This
situation can be attributed to the increasing number of
immunocompromised hosts, such as patients with AIDS, and
patients undergoing anticancer chemotherapy or organ trans-
plants.3 Clinically, Candida albicans, Cryptococcus neoformans,
and Aspergillus fumigatus have been identied as the most
common causes of systemic fungal infections.4,5 Although a
number of antifungal agents have been marketed, most of
them are used topically for the treatment of supercial fungal
infection. In contrast, there are very few antifungal agents that
can be used for life-threatening fungal infections. Generally,
four classes of antifungal agents, namely amphotericin B,6 5-
uorocytosine, azoles (such as uconazole and itraconazole),7
and echinocandins (such as caspofungin and micafungin),8 are
clinically available for antifungal therapy of systemic infec-
tions. However, these antifungal agents suffer from limited
efficacy and spectrum, drug related toxicity, non-optimal
pharmacokinetics, and serious drug–drug interactions.9 In
particular, severe resistance to antifungal drugs is becoming a
serious problem.10 Therefore, there is an emergent need to
Myristoyl-CoA: protein N-myristoyltransferase (NMT) is a
promising target enzyme for the development of novel fungi-
cidal drugs having a broad antifungal spectrum.11 Although a
number of NMT inhibitors have been reported, only the
benzoheterocyclic inhibitors (Fig. 1), such as benzofuran,12–16
benzothiazole16,17 and benzoxazole18 derivatives, showed high
selectivity and good antifungal activity. Continuing our efforts
on the discovery of novel NMT inhibitors,18–20 herein we found a
Saccharomyces cerevisiae NMT inhibitor bearing the tetra-
hydrocarbazole scaffold to possess broad-spectrum antifungal
activity. Moreover, structure–activity relationships (SARs) of the
tetrahydrocarbazole derivatives were investigated. Several
derivatives showed potent antifungal activity, and they can serve
as good starting points for the discovery of novel antifungal
agents.
Results and discussion
Chemistry
A synthetic route towards the tetrahydrocarbazole derivatives is
outlined in Schemes 1–4. In the presence of ammonium acetate,
cyclohexanone was a-brominated by N-bromosuccinimide
(NBS) to give 2-bromocyclohexanone (5). Then, compound 5 was
condensed with p-toluidine to afford methyl tetrahy-
drocarbazole 6, which was subsequently alkylated by 2-(chloro-
methyl)oxirane or 1,3-dibromopropane with KOH as a base.
Target compounds 3 and 8a–c were obtained by a ring-opening
reaction of oxirane 7 with various amines (Scheme 1). On the
other hand, reacting intermediate 9 with amines or substituted
benzyl amines in the presence of KOH and DMF gave the target
compounds 10a–d and 11a–i with moderate to good yields.
aSchool of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai
200433, People's Republic of China. E-mail: zhangwnk@hotmail.com; shengcq@
hotmail.com; Fax: +86-21-81870243; +86-21-81871233; Tel: +86-21-81870243; +86-
21-81871233
bNovel Technology Center of Pharmaceutical Chemistry, Shanghai Institute of
Pharmaceutical Industry, Shanghai 200040, People's Republic of China
cDepartment of Dermatology and Mycology Center, Changzheng Hospital, Second
Military Medical University, Shanghai 20003, People's Republic of China. E-mail:
guchen7941@hotmail.com; Fax: +86-21-81885492; Tel: +86-21-81885492
† These two authors contributed equally to this work.
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Fig. 1 Representative structures of small-molecule NMT inhibitors.
Compound 14 was prepared by a similar procedure to that
described above (Scheme 2). Reduction of compound 14 by
LiAlH4 afforded hydroxyl intermediate 15. Aer the protection of
the amine group by (Boc)2O, compound 15 was converted to ester
17 by reacting with benzoyl chloride or oxidized to aldehyde 19 by
pyridinium chlorochromate (PCC). Compound 20 was obtained
by reductive amination of aldehyde 19 followed by the depro-
tection of the amine group. The amine group of intermediate 14
was protected by (Boc)2O, and then hydrolyzed to acid 22 by
LiOH. In the presence of 1-(3-dimethylaminopropyl)-3-ethyl-
carbodiimide hydrochloride (EDC$HCl) and 4-dimethylamino-
pryidine (DMAP), acid 22 was converted to esters 23a–c and
amides 23d–g, which were deprotected to give the corresponding
target compounds 24a–g (Scheme 3). Under similar conditions,
acid 22 was acylated by morpholine to afford compound 25. In
the presence of n-BuLi and tetramethylethylenediamine
(TMEDA), the addition of 2-lithiated pyridine or thiazole gener-
ꢁ
ated in situ to intermediate 25 at ꢀ78 C and subsequent de-
protection of the Boc group with HCl afforded ketone
compounds 27a–c.
Scheme 1 Reagents and conditions: (a) NBS, NH4Ac, Et2O, rt, 0.5–1 h, 78%; (b) p-
toluidine, N2, 130 ꢁC, 12 h, 50%; (c) 2-(chloromethyl)oxirane, KOH, DMSO, rt, 2 h,
96%; (d) amines (cyclohexanamine, aniline, benzyl amine and 3-(aminomethyl)
pyridine), EtOH, reflux, 4 h, 41–53%; (e) 1,3-dibromopropane, KOH, DMSO, rt, 3 h,
42%; (f) amines, K2CO3, DMF, 80 ꢁC, 4 h, 56–63%. (g) Substituted benzyl amines,
K2CO3, DMF, 80 ꢁC, 4 h, 35–89%.
Discovery of a tetrahydrocarbazole derivative as an antifungal
lead
Previously, Ding and co-workers reported the crystal structure of
full-length Saccharomyces cerevisiae NMT (ScNMT) in ternary
complexes with myristoyl-CoA (MYA) and highly potent tetrahy-
drocarbazole inhibitor3 (IC50 ¼ 24nM).21 Although Saccharomyces
cerevisiae does not belong to the family of pathogenic fungi, the
crystal structure of ScNMT shares high similarity with that of
Candida albicans NMT (CaNMT).22,23 ScNMT inhibitors, such as
SC-58272, also possess similar CaNMT inhibitory activity.24 Thus,
we wondered whether tetrahydrocarbazole inhibitor 3 had anti-
delight, compound 3 had broad-spectrum inhibitory activity
(Table 1) against a wide range of fungal pathogens (MIC range: 16
to 64 mg mLꢀ1). Inspired by the results, compound 3 was used as a
hit or lead compound for further structural optimization.
Antifungal activity and SAR of tetrahydrocarbazole derivatives
fungal activity. To validate our hypothesis, compound 3 was Firstly, we aimed to investigate the effect of the terminal
synthesized and tested for in vitro antifungal activity. To our cyclohexyl group of compound 3 on the antifungal activity. The
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Scheme 4 Reagents and conditions: (a) morpholine, EDC$HCl, DMAP, CH2Cl2, rt,
12 h, 71%; (b) 2-bromo heterocycle, n-BuLi, TMEDA, ꢀ78 ꢁC, N2, THF, 1 h, 39–53%
and (c) HCl/EtOAc, rt, 12h, 87–93%.
Table 1 In vitro antifungal activities of the N9-modified tetrahydrocarbazole
derivatives (MIC80, mg mLꢀ1 a
)
C.
C.
A.
Compd alb.
neo. C. tro. C. par. C. kef. T. rub. fum. M. gyp.
Scheme 2 Reagents and conditions: (a) ethyl 4-aminobenzoate, N2, ECS, 130 ꢁC,
12 h, 43%; (b) 1,3-dibromopropane, KOH, DMSO, rt, 3 h, 40%; (c) benzyl amine,
K2CO3, DMF, 80 ꢁC, 4 h, 64%; (d) LiAlH4, THF, 0 ꢁC–rt, 1 h, 63%; (e) Boc2O, Et3N,
CH2Cl2, 0 ꢁC–rt, 2 h, 95%; (f) benzoyl chloride, Et3N, CH2Cl2, rt, 12 h, 55%; (g) PCC,
CH2Cl2, rt, 2 h, 22%; (h) HCl/EtOAc, rt, 2 h, 36%; (i) aniline, AcOH, NaBH3CN, N2,
MeOH, rt, 12h, 60% and (j) HCl/EtOAc, rt, 2 h, 86%.
3
8a
8b
8c
64
>64
16
>64
>64
64
16
64
64
>64
>64
>64
>64
>64
32
32
>64
4
16
>64 n.d.
64
64 n.d.
>64 n.d.
64
16
n.d.
64
n.d.
n.d.
16
16
64
32
64
>64
32
>64
>64
32
16
>64
4
64
n.d.
64
n.d.
n.d.
16
32
16
16
>64
16
16
>64
64
16
16
>64
4
4
16
n.d.
16
n.d.
n.d.
16
4
64
>64
64
64
>64
16
32
64
32 n.d.
>64 n.d.
16 n.d.
16 n.d.
>64 n.d.
>64 n.d.
32 n.d.
16 n.d.
>64 n.d.
>64 >64
16
1
16
16
4
0.0625
0.0156
0.0625
4
10a
10b
10c
10d
11a
11b
11c
11d
11e
11f
11g
11h
11i
1
16
1
64
8
16
32
16
8
4
8
64 >64
64
64
>64
>64
>64
8
>64
>64
32
64
>64 >64
32 >64
8
16
16
8
8
>64 >64
>64
64
1
>64
1
8
2
FLZ
0.5
4
>64
1
a
Abbreviations: C. alb. Candida albicans; C. neo. Cryptococcus
neoformans; C. tro. Candida tropicalis; C. par. Candida parapsilosis; C.
kef. Candida kefyr; T. rub. Trichophyton rubrum; A. fum. Aspergillus
fumigatus; M. gyp. Microsporum gypseum; n.d. not determined; FLZ:
Fluconazole.
Scheme 3 Reagents and conditions: (a) Boc2O, Et3N, CH2Cl2, 0 ꢁC–rt, 2 h, 96%;
(b) LiOH$H2O, THF : MeOH : H2O (4 : 2 : 1), 50 ꢁC, 24 h, 87%; (c) phenol, alcohol
or amine, EDC$HCl, DMAP, CH2Cl2, rt, 12 h and (d) HCl/EtOAc, rt, 12 h, 80–95%.
an increased antifungal activity and broader spectrum.
Compounds 10a–c showed moderate to good inhibitory activity
against all the tested pathogenic fungi. In particular,
compounds 10b and 10c were highly active against M. gypseum
(MIC range: 0.016 to 0.0625 mg mLꢀ1), which were more potent
than uconazole and benzofuran NMT inhibitor 1. Among
them, the best antifungal activity was observed for benzyl
derivative 10c. Notably, compound 10c showed comparable
activity (MIC ¼ 1 mg mLꢀ1) against clinically important patho-
genic fungi C. neoformans to uconazole, whereas benzofuran
NMT inhibitor 1 was inactive. Thirdly, with regard to the good
antifungal activity of compound 10c, various substitutions were
introduced on its phenyl ring to afford compounds 11a–i.
Unfortunately, decreased antifungal activity was observed for
these substituted benzyl derivatives. With the exception of
cyclohexyl group was replaced by a phenyl (8a), benzyl (8b) and
pyridine-3-ylmethyl (8c) group, respectively. An in vitro anti-
fungal activity assay (Table 1) indicated that the phenyl and
pyridyl derivatives 8a and 8c showed signicantly decreased
potency. Except for their moderate activity against M. gypseum,
compounds 8a and 8c were almost inactive. In contrast, benzyl
derivative 8b showed improved activity with a broad spectrum
(MIC range: 4 to 64 mg mLꢀ1), suggesting that the benzyl group
was more favorable than the cyclohexyl group. Secondly, the
importance of the side-chain hydroxyl group was investigated.
Interestingly, the removal of the hydroxyl group generally led to
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compounds 11a, 11g and 11h, the remaining compounds were
marginally active. A. fumigatus is the leading cause of mortality
in invasive fungal infections. However, uconazole and benzo-
furan inhibitor 1 were inactive in the assay. Interestingly,
compounds 11a, 11g and 11h showed moderate inhibition
against A. fumigatus with MIC values ranging from 16 to 32 mg
mLꢀ1. For the SAR of the substitutions on the benzyl group, the
substitutions were more favorable at the para-position than at
the ortho- and meta-position. For example, 4-uoro derivative
11a was more potent than 3-uoro derivative 11b and 2-uoro
derivative 11c. Active compounds in this series, such as 11g and
11h, are also 4-substituted analogues.
Next, modications on the C6-methyl group of compound 10c
were performed. The replacement of the C6-methyl group of
compound 10c by an ethyl carboxylate (14) or hydroxymethyl group
(15) resulted in the loss of the antifungal activity (Table 2). Further
esterication of compound 15 to ester 18 did not improve the
antifungal activity. When the ester group of compound 18 was
replaced by the amine group, compound 20 showed moderate
inhibitory activity against C. albicans (MIC ¼ 32 mgmLꢀ1), butitwas
also inactive against other tested pathogenic fungi. Variation of the
ester group of compound 14 led to the increased antifungal activity
(compounds 24a–c). Two piperidinyl ester derivatives 24b and 24c
showed broad-spectrum antifungal activity (MIC range: 8 to 64 mg
mLꢀ1). However, they were also slightly less potent than C6-methyl
derivative 10c. In contrast, the amide derivatives 24d–g generally
Conclusion
In summary, a ScNMT inhibitor with a tetrahydrocarbazole
scaffold was found to possess antifungal activity and was used
as a lead for structural optimization. A series of N9- and C6-
modied derivatives were designed and synthesized. Several
compounds showed moderate to good antifungal activity with a
broad spectrum. Results of SARs indicated that the benzyl
group was optimal for the terminal group of the N9-side chain.
The hydroxyl group had little effect on the antifungal activity
and could be removed. A methyl group was favorable at the C6-
position and replacing it by various esters, amides and hetero-
cyclic ketones led to the decrease or loss of the antifungal
activity. Compound 10c showed broad-spectrum antifungal
activity. Particularly, its inhibitory activity against C. neofor-
mans, A. fumigatus and M. gypseum was comparable or superior
to that of uconazole and benzofuran NMT inhibitor 1, which
can serve as a good starting point for the development of novel
antifungal agents. The investigation of the mode of action of
compound 10c is in progress and the results will provide
important information for lead optimization.
Experimental section
Chemistry
GENERAL METHODS. Melting points (mp) were determined by
showed poor antifungal activity. Only compounds 24d and 24e were a microscope melting-point apparatus with an automatic
moderately active against C. albicans and C. neoforamns (MIC range: temperature control system (XT4A). Nuclear magnetic reso-
16 to 64 mg mLꢀ1). Inspired by the heterocyclic carbonyl side chain nance (NMR) spectra were recorded on a Bruker 500 spec-
of the benzofuran NMT inhibitors,13 three pydinyl carbonyl or trometer with TMS as an internal standard and CDCl3 or d6-
thiazol carbonyl derivatives were synthesized. Unfortunately, DMSO as the solvent. Chemical shis (d values) and coupling
compounds 27a–c were only marginally active against C. albicans, constants (J values) are given in ppm and Hz, respectively. ESI
indicating that the SARs of the tetrahydrocarbazole NMT inhibitors mass spectra were recorded on an API-3000 LC-MS spectro-
were different from those of the benzofuran inhibitors.
meter. High-resolution mass spectroscopy measurements were
performed on a Kratos-concep mass spectrometer under elec-
tron impact ionization (EI) conditions. Elemental analyses were
performed with a MOD-1106 instrument and were consistent
with theoretical values within ꢂ0.4%. TLC analysis was carried
out on silica gel plates GF254 (Qindao Haiyang Chemical,
China). Silica gel column chromatography was performed with
Silica gel 60 G (Qindao Haiyang Chemical, China). Commercial
solvents were used without any pretreatment.
2-BROMOCYCLOHEXANONE (5). A solution of cyclohexanone
(9.81 g, 0.10 mol), NBS (19.46 g, 0.11 mol) and ammonium
acetate (0.77 g, 0.01 mol) in anhydrous diethyl ether (100 mL)
was stirred for 0.5 h at room temperature. The precipitate was
ltered and the solvent was removed under reduced pressure.
The residue was puried by silica gel column chromatography
(hexane : EtOAc ¼ 40 : 1) to give 13.68 g of compound 5 (yield:
78%) as a yellow oil.25 1H NMR (DMSO-d6, 500 MHz) d: 4.43–4.46
(m, 1H), 2.96–2.99 (m, 1H), 2.30–2.36 (m, 2H), 2.23–2.25 (m,
1H), 2.01–2.04 (m, 2H), 1.74–1.83 (m, 2H); ESI-MS (m/z): 178
[M + 1].
Table 2 In vitro antifungal activities of the C6-modified tetrahydrocarbazole
derivatives (MIC80, mg mLꢀ1 a
)
Compd
C. alb.
C. neo.
C. tro.
C. par.
C. kef.
A. fum.
14
15
18
20
>64
>64
>64
32
64
32
32
32
32
>64
64
>64
>64
>64
>64
>64
32
16
64
16
64
>64
64
>64
>64
>64
1
>64
>64
>64
>64
>64
8
>64
>64
>64
>64
>64
32
>64
>64
>64
>64
>64
64
>64
>64
>64
>64
64
>64
32
>64
64
>64
>64
>64
>64
>64
>64
>64
24a
24b
24c
24d
24e
24f
24g
27a
27b
27c
1
32
64
32
>64
>64
>64
>64
>64
>64
>64
8
>64
>64
>64
>64
>64
>64
>64
4
>64
>64
>64
>64
>64
>64
>64
4
64
64
32
4
FLZ
0.5
2
4
4
6-METHYL-2,3,4,9-TETRAHYDRO-1H-CARBAZOLE (6). To a stirring
solution of p-toluidine (22.48 g, 0.21 mol) in ethylene glycol
monomethyl ether (150 mL) was added compound 5 (12.32 g,
0.07 mol) and the resulting mixture was stirred at reux under a
a
Abbreviations: C. alb. Candida albicans; C. neo. Cryptococcus
neoformans; C. tro. Candida tropicalis; C. par. Candida parapsilosis; C.
kef. Candida kefyr; T. rub. Trichophyton rubrum; A. fum. Aspergillus
fumigatus; FLZ: Fluconazole; n.d.: not determined.
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nitrogen atmosphere for 12 h. The solvent was removed under 2H), 2.60–2.78 (m, 4H), 2.44 (s, 3H), 1.83–1.91 (m, 4H). ESI-MS
reduced pressure and the residue was puried by silica gel (m/z): 349 [M + 1]. Anal. calcd for C22H27N3O: C, 75.61; H, 7.79;
column chromatography (hexane : EtOAc ¼ 40 : 1) to give 6.41 g N, 12.02. Found: C, 75.58; H, 8.03; N, 12.05%.
of compound 6 (yield: 50%) as white needles.25 Mp: 138–139 ꢁC.
9-(3-BROMOPROPYL)-6-METHYL-2,3,4,9-TETRAHYDRO-1H-CARBA-
1H NMR (CDCl3, 500 MHz) d: 7.54 (s, 1H), 7.24 (s, 1H), 7.15 (d, J ZOLE (9). KOH (4.60 g, 80 mmol) was added to a stirring solution
¼ 8.2 Hz, 1H), 6.92 (d, J ¼ 8.2 Hz, 1H), 2.66–2.72 (m, 4H), 2.43 (s, of compound 6 (3.80 g, 20 mmol) and 1,3-dibromopropane
3H), 1.85–1.91 (m, 4H). ESI-MS (m/z): 184 [M ꢀ 1]. The synthetic (16.41 g, 80 mmol) in DMSO (50 mL) and the resulting mixture
method for compound 12 was similar to that of compound 6.
was stirred at room temperature for 3 h. The mixture was
6-METHYL-9-(OXIRAN-2-YLMETHYL)-2,3,4,9-TETRAHYDRO-1H- diluted with water (50 mL) and then extracted with EtOAc (3 ꢃ
CARBAZOLE (7). KOH (1.12 g, 10 mmol) was added to a stirring 100 mL). The combined organic layers were washed with satu-
solution of compound 6 (0.91 g, 5 mmol) and 3-chloro-1,2- rated sodium chloride solution (3 ꢃ 100 mL), dried over anhy-
epoxypropane (3.70 g, 10 mmol) in DMSO (20 mL) and the drous Na2SO4 and concentrated under reduced pressure. Silica
resulting mixture was stirred at room temperature for 2 h. The gel column chromatography with an eluent system hexane–
mixture was diluted with water (40 mL) and then extracted with EtOAc (40 : 1) gave 2.65 g of compound 9 (yield: 42%) as a white
CH3Cl (3 ꢃ 40 mL). The combined organic layers were washed solid. 1H NMR (CDCl3, 500 MHz) d: 7.25 (s, 1H), 7.14 (d, J ¼ 7.8
with saturated sodium chloride solution (3 ꢃ 50 mL), dried over Hz, 1H), 6.95 (d, J ¼ 7.8 Hz, 1H), 4.15 (t, J ¼ 6.7 Hz, 2H), 3.35 (t, J
anhydrous Na2SO4 and concentrated under reduced pressure. ¼ 6.3 Hz, 2H), 2.67–2.73 (m, 4H), 2.44 (s, 3H), 2.27–2.29 (m, 2H),
The residue was puried by silica gel column chromatography 1.92–1.95 (m, 2H), 1.83–1.85 (m, 2H). ESI-MS (m/z): 307 [M + 1].
(hexane : EtOAc ¼ 10 : 1) to give 1.14 g of compound 7 (yield: Anal. calcd for C16H20BrN: C, 62.75; H, 6.58; N, 4.57. Found: C,
96%) as a yellow oil. 1H NMR (CDCl3, 500 MHz) d: 7.22 (s, 1H), 62.80; H, 6.52; N, 4.53%. The synthetic method for compound
7.14 (d, J ¼ 8.1 Hz, 1H), 6.90 (d, J ¼ 8.1 Hz, 1H), 4.17–4.31 (m, 13 was similar to that of compound 9.
2H), 4.10–4.17 (m, 2H), 3.19–3.22 (m, 1H), 2.71–2.77 (m, 4H),
N-(3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)PROPYL)-
2.67 (s, 3H), 1.84–1.96 (m, 4H). ESI-MS (m/z): 242 [M + 1]. Anal. CYCLOHEXANAMINE (10A). K2CO3 (0.28 g, 2 mmol) was added to a
calcd for C16H19NO: C, 79.63; H, 7.94; N, 5.80. Found: C, 79.60; stirring solution of compound 9 (0.31 g, 1 mmol) and cyclo-
H, 7.89; N, 5.82%.
hexylamine (0.79 g, 8 mmol) in DMF (10 mL) and the resulting
1-(CYCLOHEXYLAMINO)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBA- mixture was stirred at 80 ꢁC for 3 h. Then, ethyl acetate was
ZOL-9(2H)-YL)PROPAN-2-OL (3). A solution of compound 7 (0.24 g, added (25 mL), followed by washing with water (3 ꢃ 10 mL) and
1 mmol) and cyclohexylamine (1.59 g, 16 mmol) in ethanol (10 brine (1 ꢃ 10 mL). The organic layer was dried over Na2SO4 and
mL) was stirred for 4 h at reux. The solvent was removed under the solvent was evaporated under reduced pressure. The residue
reduced pressure and the crude product was puried by silica was puried by silica gel column chromatography
gel column chromatography (CH2Cl2 : MeOH ¼ 10 : 1) to give (CH2Cl2 : MeOH ¼ 20 : 1) to give 0.18 g of compound 10a (56%)
0.18 g of compound 3 (yield: 53%) as a white solid. Mp: 98–99 as a yellow oil. 1H NMR (CDCl3, 500 MHz) d: 7.22 (s, 1H), 7.11 (d,
ꢁC. 1H NMR (CDCl3, 500 MHz) d: 7.27 (s, 1H), 7.20 (d, J ¼ 7.8 Hz, J ¼ 7.8 Hz, 1H), 6.95 (d, J ¼ 7.7 Hz, 1H), 4.04 (t, J ¼ 6.9 Hz, 2H),
1H), 6.98 (d, J ¼ 7.8 Hz, 1H), 4.01–4.08 (m, 3H), 2.76–2.82 (m, 3.22 (t, J ¼ 6.9 Hz, 2H), 2.55–2.67 (m, 4H), 2.35 (s, 3H), 1.90–1.95
1H), 2.68–2.74 (m, 4H), 2.50–2.57 (m, 1H), 2.45 (s, 3H), 1.88–1.95 (m, 2H), 1.88–1.94 (m, 4H), 0.98–2.35 (m, 13H). ESI-MS (m/z):
(m, 4H), 0.97–2.33 (m, 13H). ESI-MS (m/z): 341 [M + 1]. Anal. 325 [M + 1]. Anal. calcd for C22H32N2: C, 81.43; H, 9.94; N, 8.63.
calcd for C22H32N2O: C, 77.60; H, 9.47; N, 8.23. Found: C, 77.67; Found: C, 81.45; H, 9.90; N, 8.75%. The synthetic method for
H, 9.42; N, 8.20%. The synthetic method for compound 8a–c compound 10b–d, 11a–i, and 14 was similar to the synthesis of
was similar to that of compound 3.
compound 10a.
1-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)-3-(PHENYL-
N-(3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)-
AMINO)PROPAN-2-OL (8A). Red oil: 0.14 g (yield: 42%). 1H NMR PROPYL)ANILINE (10B). Yellow oil: 0.20 g (yield: 63%). 1H NMR
(CDCl3, 500 MHz) d: 7.23 (s, 1H), 7.00–7.18 (m, 6H), 6.68 (d, J ¼ (CDCl3, 500 MHz) d: 7.15 (s, 1H), 6.53–7.08 (m, 7H), 4.14 (t, J ¼
7.8 Hz, 1H), 4.27–4.32 (m, 1H), 4.13 (d, J ¼ 6.9 Hz, 2H), 3.13–3.35 6.9 Hz, 2H), 3.12 (t, J ¼ 6.9 Hz, 2H), 2.65–2.72 (m, 4H), 2.46 (s,
(m, 2H), 2.68–2.73 (m, 4H), 2.45 (s, 3H), 1.83–1.94 (m, 4H). ESI- 3H), 1.93–1.97 (m, 2H), 1.82–1.85 (m, 4H). ESI-MS (m/z): 319
MS (m/z): 334 [M + 1]. Anal. calcd for C22H26N2O: C, 79.00; H, [M + 1]. Anal. calcd for C22H26N2: C, 82.97; H, 8.23; N, 8.80.
7.84; N, 8.38. Found: C, 78.97; H, 7.80; N, 8.32%.
Found: C, 82.95; H, 8.27; N, 8.78%.
1-(BENZYLAMINO)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-
N-BENZYL-3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)-
1
1
9(2H)-YL)PROPAN-2-OL (8B). Red oil: 0.14 g (yield: 41%). H NMR PROPAN-1-AMINE (10C). Yellow oil: 0.22 g (yield: 67%). H NMR
(CDCl3, 500 MHz) d: 7.35 (s, 1H), 7.02–7.19 (m, 6H), 6.94 (d, J ¼ (CDCl3, 500 MHz) d: 7.39 (s, 1H), 7.00–7.30 (m, 6H), 6.94 (d, J ¼
8.0 Hz, 1H), 6.94–7.35 (m, 8H), 4.04 (m, 3H), 3.85 (s, 2H), 3.74 (d, 7.8 Hz, 1H), 4.09 (t, J ¼ 6.9 Hz, 2H), 3.75 (s, 2H), 2.90–2.97 (m,
J ¼ 8.5 Hz, 2H), 2.62–2.79 (m, 4H), 2.44 (s, 3H), 1.83–1.97 (m, 2H), 2.63–2.72 (m, 4H), 2.45 (s, 3H), 1.93–2.04 (m, 2H), 1.72–1.91
4H). ESI-MS (m/z): 348 [M + 1]. Anal. calcd for C23H28N2O: C, (m, 4H). ESI-MS (m/z): 333 [M + 1]. Anal. calcd for C23H28N2: C,
79.27; H, 8.10; N, 8.04. Found: C, 79.29; H, 8.02; N, 8.00%.
83.09; H, 8.49; N, 8.43. Found: C, 83.04; H, 8.51; N, 8.45%.
1-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)-3-((PYRIDIN-
3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)-N-(PYRIDIN-
3-YLMETHYL)AMINO)PROPAN-2-OL (8C). Red oil: 0.15 g (yield: 43%). 3-YLMETHYL)PROPAN-1-AMINE (10D). Yellow oil: 0.19 g (yield:
1
1H NMR (CDCl3, 500 MHz) d: 6.94–8.54 (m, 7H), 4.10–4.24 (m, 58%). H NMR (CDCl3, 500 MHz) d: 6.94–8.54 (m, 7H), 4.08 (t,
1H), 4.03–4.08 (m, 2H), 3.79 (d, J ¼ 19.5 Hz, 2H), 2.73–2.81 (m, J ¼ 6.9 Hz, 2H), 3.73 (s, 2H), 3.10–3.18 (m, 2H), 2.68–2.86 (m,
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2H), 2.64–2.66 (m, 4H), 2.44 (s, 3H), 1.80–1.95 (m, 4H). ESI-MS MS (m/z): 367 [M + 1]. Anal. calcd for C23H27ClN2: C, 75.29; H,
(m/z): 356 [M + Na]. Anal. calcd for C22H27N3: C, 79.24; H, 8.16; 7.42; N, 7.63. Found: C, 75.27; H, 7.39; N, 7.65%.
N, 12.60. Found: C, 79.29; H, 8.10; N, 12.61%.
3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL-9(2H)-YL)-N-(4-METHYL-
N-(4-FLUOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL- BENZYL)PROPAN-1-AMINE (11G). Yellow oil: 0.28 g (yield: 82%). 1H
9(2H)-YL)PROPAN-1-AMINE (11A). Yellow oil: 0.12 g (yield: 35%). 1H NMR (CDCl3, 500 MHz) d: 7.23 (s, 1H), 7.17 (d, J ¼ 7.7 Hz, 2H),
NMR (CDCl3, 500 MHz) d: 7.21–7.24 (m, 3H), 7.15 (d, J ¼ 8.2 Hz, 7.13 (t, J ¼ 7.9 Hz, 3H), 6.94 (d, J ¼ 7.7 Hz, 1H), 4.06 (t, J ¼ 6.9 Hz,
1H), 6.98 (t, J ¼ 8.6 Hz, 2H), 6.94 (d, J ¼ 8.2 Hz, 1H), 4.07 (t, J ¼ 2H), 3.70 (s, 2H), 2.63–2.67 (m, 6H), 2.44 (s, 3H), 2.33 (s, 3H),
6.9 Hz, 2H), 3.69 (s, 2H), 2.66–2.68 (m, 4H), 2.62 (t, J ¼ 6.8 Hz, 1.82–1.97 (m, 6H). 13C NMR (CDCl3, 125 MHz) d: 137.59, 135.25,
2H), 2.44 (s, 3H), 1.89–1.94 (m, 4H), 1.81–1.84 (m, 2H). ESI-MS 134.46, 139.32, 128.96, 128.90, 127.81, 127.59, 122.05, 117.64, 109.06,
(m/z): 351 [M + 1]. Anal. calcd for C23H27FN2: C, 78.82; H, 7.77; N, 108.39, 52.64, 45.63, 40.46, 29.70, 29.32, 23.34, 23.21, 22.27, 21.42,
7.99. Found: C, 78.79; H, 7.84; N, 7.95%.
21.13. ESI-MS (m/z): 347 [M + 1]. Anal. calcd for C24H30N2: C, 83.19; H,
N-(3-FLUOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL- 8.73; N, 8.08. Found: C, 83.15; H, 8.78; N, 8.07%.
9(2H)-YL)PROPAN-1-AMINE (11B). Yellow oil: 0.16 g (yield: 46%). 1H
N-(4-METHOXYBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBA-
NMR (CDCl3, 500 MHz) d: 7.26–7.28 (m, 1H), 7.25 (s, 1H), 7.16 ZOL-9(2H)-YL)PROPAN-1-AMINE (11H). Yellow oil: 0.32 g (yield:
(d, J ¼ 8.2 Hz, 1H), 7.04 (d, J ¼ 7.5 Hz, 1H), 7.00 (d, J ¼ 9.8 Hz, 89%). 1H NMR (CDCl3, 500 MHz) d: 7.23 (s, 1H), 7.19 (d, J ¼ 8.5
1H), 6.94 (d, J ¼ 8.4 Hz, 2H), 4.08 (t, J ¼ 6.9 Hz, 2H), 3.72 (s, 2H), Hz, 2H), 7.16 (d, J ¼ 8.2 Hz, 1H), 6.94 (d, J ¼ 8.2 Hz, 2H), 6.85 (d,
2.66–2.69 (m, 4H), 2.63 (t, J ¼ 6.8 Hz, 2H), 2.44 (s, 3H), 1.89–1.95 J ¼ 8.5 Hz, 2H), 4.06 (t, J ¼ 6.9 Hz, 2H), 3.80 (s, 3H), 3.67 (s, 2H),
(m, 4H), 1.80–1.84 (m, 2H). 13C NMR (CDCl3, 125 MHz) d: 2.65–2.69 (m, 4H), 2.63 (t, J ¼ 6.8 Hz, 2H), 2.44 (s, 3H), 1.90–1.94
135.32, 134.51, 129.89, 129.84, 127.75, 127.56, 123.75, 121.96, (m, 4H), 1.81–1.84 (m, 2H). 13C NMR (CDCl3, 125 MHz) d:
117.63, 115.09, 114.95, 113.90, 108.92, 108.41, 53.31, 46.55, 158.93, 135.32, 134.49, 129.73, 127.73, 127.56, 121.96, 117.60,
40.65, 30.42, 29.71, 23.36, 22.27, 21.43, 21.08. ESI-MS (m/z): 351 113.89, 113.60, 108.91, 108.43, 55.26, 52.97, 46.16, 40.61, 30.07,
[M + 1]. Anal. calcd for C23H27FN2: C, 78.82; H, 7.77; N, 7.99. 23.36, 23.25, 22.28, 21.42, 21.07. ESI-MS (m/z): 363 [M + 1]. Anal.
Found: C, 78.80; H, 7.81; N, 7.96%.
calcd for C24H30N2O: C, 79.52; H, 8.34; N, 7.73. Found: C, 79.50;
N-(2-FLUOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBAZOL- H, 8.38; N, 7.77%.
9(2H)-YL)PROPAN-1-AMINE (11C). Yellow oil: 0.13 g (yield: 37%). 1H
N-(2,4-DICHLOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CAR-
NMR (CDCl3, 500 MHz) d: 7.22–7.26 (m, 3H), 7.16 (d, J ¼ 8.2 Hz, BAZOL-9(2H)-YL)PROPAN-1-AMINE (11I). Yellow oil: 0.27 g (yield:
1
1H), 7.08 (t, J ¼ 7.5 Hz, 1H), 7.02 (t, J ¼ 7.5 Hz, 1H), 6.93 (d, J ¼ 68%). H NMR (CDCl3, 500 MHz) d: 7.36 (d, J ¼ 1.9 Hz, 1H),
8.2 Hz, 1H), 4.07 (t, J ¼ 6.9 Hz, 2H), 3.80 (s, 2H), 2.66–2.69 (m, 7.22–7.24 (m, 2H), 7.14–7.19 (m, 2H), 6.93 (d, J ¼ 7.4 Hz, 1H),
4H), 2.63 (t, J ¼ 6.8 Hz, 2H), 2.44 (s, 3H), 1.89–1.94 (m, 4H), 1.81– 4.07 (t, J ¼ 6.9 Hz, 2H), 3.78 (s, 2H), 2.65–2.70 (m, 4H), 2.60
1.84 (m, 2H). ESI-MS (m/z): 351 [M + 1]. Anal. calcd for (t, J ¼ 6.8 Hz, 2H), 2.44 (s, 3H), 1.88–1.93 (m, 4H), 1.81–1.84
C
23H27FN2: C, 78.82; H, 7.77; N, 7.99. Found: C, 78.78; H, 7.79; (m, 2H). ESI-MS (m/z): 401 [M
+
1]. Anal. Calcd for
23H26Cl2N2: C, 68.83; H, 6.53; N, 6.98. Found: C, 68.78; H,
N-(4-CHLOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBA- 6.52; N, 7.02%.
ZOL-9(2H)-YL)PROPAN-1-AMINE (11D). Yellow oil: 0.23 g (yield: ETHYL 2,3,4,9-TETRAHYDRO-1H-CARBAZOLE-6-CARBOXYLATE (12).
N, 7.93%.
C
1
1
64%). H NMR (CDCl3, 500 MHz) d: 7.26–7.28 (m, 3H), 7.19 (d, Yellow solid: 7.27 g (yield: 43%). H NMR (CDCl3, 500 MHz) d:
J ¼ 8.5 Hz, 2H), 7.15 (d, J ¼ 8.3 Hz, 1H), 6.94 (d, J ¼ 8.3 Hz, 1H), 8.22 (s, 1H), 7.89 (s, 1H), 7.44 (d, J ¼ 8.6 Hz, 1H), 7.25 (d, J ¼ 8.6
4.07 (t, J ¼ 6.9 Hz, 2H), 3.68 (s, 2H), 2.65–2.70 (m, 4H), 2.61 (t, Hz, 1H), 4.39 (q, J ¼ 7.1 Hz, 2H), 2.72–2.75 (m, 4H), 1.86–1.94
J ¼ 6.8 Hz, 2H), 2.44 (s, 3H), 1.87–1.93 (m, 4H), 1.81–1.84 (m, (m, 4H), 1.42 (t, J ¼ 7.1 Hz, 3H). ESI-MS (m/z): 244 [M + 1]. Anal.
2H). 13C NMR (CDCl3, 125 MHz) d: 138.31, 135.31, 134.51, calcd for C15H17NO2: C, 74.05; H, 7.04; N, 5.76. Found: C, 74.01;
132.78, 129.55, 128.52, 127.73, 127.55, 121.93, 117.61, 108.90, H, 7.00; N, 5.77%.
108.40, 53.17, 46.53, 40.65, 30.47, 23.36, 23.26, 22.28, 21.42,
21.07. ESI-MS (m/z): 367 [M + 1]. Anal. calcd for C23H27ClN2: C, 6-CARBOXYLATE (13). Yellow solid: 2.9 g (yield: 40%). 1H NMR
75.29; H, 7.42; N, 7.63. Found: C, 75.28; H, 7.44; N, 7.59%.
ETHYL 9-(3-BROMOPROPYL)-2,3,4,9-TETRAHYDRO-1H-CARBAZOLE-
(CDCl3, 500 MHz) d: 8.23 (s, 1H), 7.50 (d, J ¼ 8.6 Hz, 1H), 7.29 (d,
N-(2-CHLOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBA- J ¼ 8.6 Hz, 1H), 4.39 (q, J ¼ 7.1 Hz, 2H), 4.21 (t, J ¼ 6.8 Hz, 2H),
ZOL-9(2H)-YL)PROPAN-1-AMINE (11E). Yellow oil: 0.18 g (yield: 3.37 (t, J ¼ 6.2 Hz, 2H), 2.72–2.76 (m, 4H), 2.28–2.31 (m, 2H),
50%). 1H NMR (CDCl3, 500 MHz) d: 7.34 (d, J ¼ 2.1 Hz, 1H), 7.29 1.95–1.97 (m, 2H), 1.85–1.88 (m, 2H), 1.42 (t, J ¼ 7.1 Hz, 3H).
(d, J ¼ 2.1 Hz, 1H), 7.16–7.23 (m, 4H), 6.95 (d, J ¼ 1.1 Hz, 1H), ESI-MS (m/z): 307 [M + 1]. Anal. calcd for C18H22BrNO2: C, 59.35;
4.08 (t, J ¼ 7.0 Hz, 2H), 3.84 (s, 2H), 2.66–2.69 (m, 4H), 2.62 (t, H, 6.09; N, 3.85. Found: C, 59.33; H, 6.11; N, 3.80%.
J ¼ 6.8 Hz, 2H), 2.44 (s, 3H), 1.88–1.92 (m, 4H), 1.81–1.85 (m,
ETHYL
9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-
2H). ESI-MS (m/z): 367 [M + 1]. Anal. calcd for C23H27ClN2: C, CARBAZOLE-6-CARBOXYLATE (14). Yellow solid: 0.24 g (yield: 64%).
75.29; H, 7.42; N, 7.63. Found: C, 75.30; H, 7.45; N, 7.59%.
1H NMR (CDCl3, 500 MHz) d: 8.22 (s, 1H), 7.84 (dd, J ¼ 8.4, 1.5
N-(3-CHLOROBENZYL)-3-(6-METHYL-3,4-DIHYDRO-1H-CARBA- Hz, 1H), 7.26–7.31 (m, 4H), 7.19–7.22 (m, 1H), 6.99 (dd, J ¼ 8.4,
ZOL-9(2H)-YL)PROPAN-1-AMINE (11F). Yellow oil: 0.31 g (yield: 1.3 Hz, 1H), 4.93 (s, 1H), 4.52 (s, 2H), 4.36–4.44 (m, 2H), 4.06 (t,
86%). 1H NMR (CDCl3, 500 MHz) d: 7.28 (s, 1H), 7.23 (t, J ¼ 2.7 J ¼ 7.0 Hz, 2H), 3.28 (br, 2H), 2.66 (t, J ¼ 7.0 Hz, 2H), 2.58–2.62
Hz, 3H), 7.15 (t, J ¼ 8.2 Hz, 2H), 6.94 (d, J ¼ 8.2 Hz, 1H), 4.08 (t, (m, 2H), 1.69–1.84 (m, 6H), 1.39 (t, J ¼ 6.8 Hz, 3H); ESI-MS (m/z):
J ¼ 6.9 Hz, 2H), 3.69 (s, 2H), 2.66–2.69 (m, 4H), 2.62 (t, J ¼ 6.8 391 [M + 1]. Anal. calcd for C25H30N2O2: C, 76.89; H, 7.74; N,
Hz, 2H), 2.44 (s, 3H), 1.90–1.93 (m, 4H), 1.81–1.85 (m, 2H). ESI- 7.17. Found: C, 76.85; H, 7.78; N, 7.20%.
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(9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-CARBA-
ZOL-6-YL)METHANOL (15). Compound 14 (1.95 g, 5 mmol) in THF
(25 mL) was added dropwise at 0 ꢁC to a stirring solution of
LiAlH4 (0.76 g, 20 mmol) in anhydrous THF (25 mL). Then, the
reaction mixture was stirred for 1 h at room temperature.
Aerward, water (1 mL) was added, and stirring was continued
at 0 ꢁC for additional 1 h. The organic layer was dried over
Na2SO4 and the solvent was evaporated under reduced pressure.
The residue was puried by silica gel column chromatography
(CH2Cl2 : MeOH ¼ 100 : 2) to give 1.09 g of compound 15 (yield:
63%) as a white solid. 1H NMR (CDCl3, 500 MHz) d: 7.31 (d, J ¼
1.2 Hz, 1H), 7.24 (dd, J ¼ 8.4, 1.5 Hz, 1H), 7.07–7.20 (m, 5H), 6.99
(s, 1H), 4.95 (br s, 1H), 4.52 (s, 2H), 4.08 (t, J ¼ 7.0 Hz, 2H), 3.64
(s, 2H), 2.67–2.70 (m, 2H), 2.59–2.62 (m, 2H), 2.46 (t, J ¼ 6.6 Hz,
2H), 1.83–1.85 (m, 2H), 1.75–1.78 (m, 4H). ESI-MS (m/z): 349 [M
+ 1]. Anal. calcd for C23H28N2O: C, 79.27; H, 8.10; N, 8.04.
Found: C, 79.25; H, 8.04; N, 8.07%.
chromatography (hexane : EtOAc ¼ 2 : 1) to give 0.16 g of
compound 18 (yield: 36%) as a yellow oil. 1H NMR (CDCl3, 500
MHz) d: 7.96 (d, J ¼ 1.2 Hz, 1H), 7.60 (dd, J ¼ 8.4, 1.5 Hz, 1H),
7.28–7.41 (m, 10H), 6.48 (s, 1H), 4.71 (s, 2H), 4.13 (t, J ¼ 6.9 Hz,
2H), 3.75 (s, 2H), 2.68–2.72 (m, 4H), 2.64 (t, J ¼ 6.9 Hz, 2H), 1.85–
1.94 (m, 6H). ESI-MS (m/z): 363 [M + 1]. Anal. calcd for
C
30H32N2O2: C, 79.61; H, 7.13; N, 6.19. Found: C, 79.65; H, 7.14;
N, 6.13%.
TERT-BUTYL
BENZYL(3-(6-FORMYL-3,4-DIHYDRO-1H-CARBAZOL-
9(2H)-YL)PROPYL) CARBAMATE (19). To a stirring solution of
compound 16 (0.45 g, 1 mmol) in CH2Cl2 (10 mL) was added
pyridinium chlorochromate (0.43 g, 2 mmol) in CH2Cl2 (20 mL),
and the resulting mixture was stirred at room temperature for
2 h. The mixture was poured into EtOAc (150 mL), stirred for 10
min, and then ltered. The lter was washed with brine (1 ꢃ
50 mL), dried over Na2SO4 and evaporated under reduced
pressure. The crude product was puried by silica gel column
chromatography (hexane : EtOAc ¼ 5 : 1) to give 0.10 g of
compound 19 (yield: 22%) as a yellow oil. 1H NMR (CDCl3, 500
MHz) d: 10.01 (s, 1H), 7.99 (s, 1H), 7.67 (d, J ¼ 8.5, 1H), 7.27–7.30
(m, 3H), 7.17 (d, J ¼ 8.5, 3H), 4.39 (br, 2H), 3.97 (br, 2H), 3.25 (br,
2H), 2.73 (br, 2H), 2.59 (br, 2H), 1.85–1.93 (m, 6H), 1.46 (s, 9H).
ESI-MS (m/z): 447 [M + 1]. Anal. calcd for C28H34N2O3: C, 75.31;
H, 7.67; N, 6.27. Found: C, 75.28; H, 7.66; N, 6.23%.
N-((9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-CAR-
BAZOL-6-YL)METHYL) ANILINE (20). To a stirring solution of aniline
(0.03 g, 0.29 mmol) and acetic acid (0.03 mL, 0.58 mmol) in
MeOH (5 mL) was added compound 19 (0.13 g, 0.29 mmol) in
MeOH (5 mL) under a nitrogen atmosphere. Sodium cyano-
borohydride (0.02 g, 0.35 mmol) was added and the reaction
mixture was stirred for 12 h at room temperature. The solvent
was evaporated in vacuo. The residue was diluted with water
(15 mL), and extracted with CH2Cl2 (3 ꢃ 15 mL). The combined
organic layer was dried over Na2SO4 and the solvent was evap-
orated under reduced pressure to give the crude product. The
crude product was dissolved in EtOAc (5 mL) and HCl in EtOAc
(1 mol Lꢀ1, 5 mL) was added. The mixture was stirred for
another 2 h at room temperature, diluted with saturated
sodium carbonate (10 mL) and then extracted with EtOAc (3 ꢃ
20 mL). The combined organic layer was washed with water (2 ꢃ
20 mL) and brine (1 ꢃ 20 mL) and dried over Na2SO4. The
solvent was evaporated off and the residue was puried by silica
gel column chromatography (hexane : EtOAc ¼ 2 : 1) to give
0.06 g of compound 20 (yield: 86%) as a yellow oil. 1H NMR
(CDCl3, 500 MHz) d: 7.47 (s, 1H), 7.29–7.34 (m, 5H), 7.27 (d, J ¼
5.9 Hz, 1H), 7.18 (t, J ¼ 7.8 Hz, 2H), 7.15 (d, J ¼ 8.4 Hz, 1H), 6.72
(d, J ¼ 7.8 Hz, 1H), 6.69 (d, J ¼ 8.4 Hz, 2H), 4.40 (s, 2H), 4.13 (t,
J ¼ 6.9 Hz, 2H), 3.77 (s, 2H), 2.65–2.73 (m, 6H), 1.89–1.97 (m,
6H). 13C NMR (CDCl3, 125 MHz) d: 148.59, 135.95, 135.62,
129.40, 129.19, 128.48, 128.31, 127.51, 127.20, 120.73, 117.19,
117.12, 112.81, 109.36, 108.90, 53.82, 49.17, 46.42, 40.73, 30.39,
23.30, 23.19, 22.27, 21.07. ESI-MS (m/z): 424 [M + 1]. Anal. calcd
for C29H33N3: C, 82.23; H, 7.85; N, 9.92. Found: C, 82.28; H, 7.84;
N, 9.88%.
TERT-BUTYL
BENZYL(3-(6-(HYDROXYMETHYL)-3,4-DIHYDRO-1H-
CARBAZOL-9(2H)-YL) PROPYL)CARBAMATE (16). To a stirring solution
of compound 15 (3.48 g, 10 mmol) and Et3N (1.52 g, 15 mmol) in
CH2Cl2 (50 mL), Boc2O (2.62 g, 12 mmol) in CH2Cl2 (15 mL) was
added dropwise at 0 ꢁC. Then, the reaction mixture was stirred
for 2 h at room temperature. The mixture was washed with
water (2 ꢃ 40 mL) and brine (1 ꢃ 40 mL). The organic layer was
dried over Na2SO4 and the solvent was evaporated under
reduced pressure. The residue was puried by silica gel column
chromatography (hexane : EtOAc ¼ 3 : 1) to give 4.25 g of
compound 16 (yield: 95%) as a yellow oil. 1H NMR (CDCl3, 500
MHz) d: 7.96 (d, J ¼ 1.2 Hz, 1H), 7.58 (dd, J ¼ 8.4, 1.5 Hz, 1H),
7.17–7.43 (m, 5H), 6.44 (s, 1H), 4.71 (s, 2H), 4.38 (br, 2H), 3.96
(br, 2H), 3.26 (br, 2H), 2.71 (t, J ¼ 5.5 Hz, 2H), 2.59 (t, J ¼ 5.5 Hz,
2H), 1.85–1.90 (m, 6H), 1.46 (s, 9H). ESI-MS (m/z): 449 [M + 1].
Anal. calcd for C28H36N2O3: C, 74.97; H, 8.09; N, 6.24. Found: C,
74.95; H, 8.04; N, 6.27%.
(9-(3-(BENZYL(TERT-BUTOXYCARBONYL)AMINO)PROPYL)-2,3,4,9-
TETRAHYDRO-1H-CARBAZOL-6-YL)METHYL BENZOATE (17). Triethyl-
amine (0.08 g, 0.8 mmol) was added to a solution of compound
16 (0.18 g, 0.4 mmol) and benzoyl chloride (0.08 g, 0.6 mmol) in
anhydrous CH2Cl2 (15 mL). The reaction mixture was stirred for
12 h at room temperature. The solvent was concentrated in
vacuo and the residue was puried by silica gel column chro-
matography (hexane : EtOAc ¼ 3 : 1) to give 0.12 g of compound
17 (yield: 55%) as yellow oil. 1H NMR (CDCl3, 500 MHz) d: 7.95
(d, J ¼ 1.2 Hz, 1H), 7.58 (dd, J ¼ 8.4, 1.5 Hz, 1H), 7.28–7.41 (m,
10H), 6.43 (s, 1H), 4.71 (s, 2H), 4.38 (s, 2H), 3.96 (br, 2H), 3.26
(br, 2H), 2.71 (br, 2H), 2.59 (m, 2H), 1.84–1.89 (m, 6H), 1.46 (s,
9H). ESI-MS (m/z): 553 [M + 1]. Anal. calcd for C35H40N2O4: C,
76.06; H, 7.29; N, 5.07. Found: C, 76.05; H, 7.24; N, 5.00%.
(9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-CARBA-
ZOL-6-YL)METHYL BENZOATE (18). HCl in EtOAc (1 mol Lꢀ1, 10 mL)
was added to a solution of compound 17 (0.55 g, 1 mmol) in
EtOAc (10 mL). The reaction mixture was stirred for 2 h at room
temperature. The mixture was diluted with saturated sodium
carbonate (10 mL) and then extracted with EtOAc (3 ꢃ 20 mL).
The combined organic layer was washed with water (2 ꢃ 20 mL)
and brine (1 ꢃ 20 mL) and dried over Na2SO4. The solvent was
evaporated off and the residue was puried by silica gel column
ETHYL
9-(3-(BENZYL(TERT-BUTOXYCARBONYL)AMINO)PROPYL)-
2,3,4,9-TETRAHYDRO-1H-CARBAZOLE-6-CARBOXYLATE (21). Reaction
of compound 14 (3.91 g, 10 mmol), Et3N (1.52 g, 15 mmol) and
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Boc2O (2.62 g, 12 mmol) as described for the synthesis of 16 calcd for C28H35N3O2: C, 75.47; H, 7.92; N, 9.43. Found: C,
followed by purication using silica gel column chromato- 75.42; H, 7.89; N, 9.41%.
graphy (hexane : EtOAc ¼ 10 : 1) gave 4.70 g of compound 21
1-METHYLPIPERIDIN-4-YL-9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-
(yield: 96%) as a yellow oil. 1H NMR (CDCl3, 500 MHz) d: 8.22 (s, TETRAHYDRO-1H-CARBAZOLE-6-CARBOXYLATE (24C). Yellow oil: 0.26
1
1H), 7.84 (dd, J ¼ 8.4, 1.5 Hz, 1H), 7.28–7.33 (m, 3H), 7.10–7.13 g (yield: 88%). H NMR (CDCl3, 500 MHz) d: 8.22 (s, 1H), 7.84
(m, 3H), 4.36–4.44 (m, 4H), 3.96 (br, 2H), 3.26 (br, 2H), 2.74 (t, (dd, J ¼ 8.6, 1.5 Hz, 1H), 7.27–7.33 (m, 6H), 5.30 (s, 1H), 4.14 (t, J
J ¼ 5.5 Hz, 2H), 2.59 (br, 2H), 1.86–1.90 (m, 6H), 1.60 (s, 9H), ¼ 7.0 Hz, 2H), 3.74 (s, 2H), 2.73–2.76 (m, 2H), 2.68–2.70 (m, 2H),
1.40 (t, J ¼ 6.9 Hz, 3H). ESI-MS (m/z): 491 [M + 1]. Anal. calcd for 2.64 (t, J ¼ 6.5 Hz, 2H), 1.91–1.94 (m, 2H), 1.84–1.86 (m, 2H),
C
30H38N2O4: C, 73.44; H, 7.81; N, 5.71. Found: C, 73.40; H, 7.77; 1.58 (m, 8H), 1.43 (s, 3H). ESI-MS (m/z): 461 [M + 1]. Anal. calcd
N, 5.75%.
for C29H37N3O2: C, 75.78; H, 8.11; N, 9.14. Found: C, 75.74; H,
9-(3-(BENZYL(TERT-BUTOXYCARBONYL)AMINO)PROPYL)-2,3,4,9- 8.09; N, 9.10%.
TETRAHYDRO-1H-CARBAZOLE-6-CARBOXYLIC ACID (22). To a stirring
9-(3-(BENZYLAMINO)PROPYL)-N-PHENYL-2,3,4,9-TETRAHYDRO-1H-
solution of compound 21 (4.91 g, 10 mmol) in THF (40 mL) was CARBAZOLE-6-CARBOXAMIDE (24D). Yellow oil: 0.31 g (yield: 95%).
added LiOH$H2O (2.10 g, 50 mmol) at 0 ꢁC. Water (10 mL) and 1H NMR (CDCl3, 500 MHz) d: 8.04 (d, J ¼ 1.2 Hz, 1H), 7.92 (s,
MeOH (20 mL) were added and then the mixture was stirred at 1H), 7.71 (d, J ¼ 8.7 Hz, 2H), 7.65 (d, J ¼ 1.2 Hz, 1H), 7.16–7.41
50 ꢁC for 24 h. The solvent was evaporated in vacuo. The residue (m, 7H), 7.13 (t, J ¼ 6.6 Hz, 1H), 4.16 (t, J ¼ 6.9 Hz, 2H), 3.76 (s,
was diluted with saturated ammonium chloride solution (50 2H), 2.71–2.79 (m, 4H), 2.66 (t, J ¼ 6.6 Hz, 2H), 1.89–1.96 (m,
mL), and extracted with EtOAc (3 ꢃ 50 mL). The combined 6H). 13C NMR (CDCl3, 125 MHz) d: 167.03, 140.18, 138.64,
organic layer was dried over Na2SO4 and the solvent was evap- 138.20, 137.22, 128.99, 128.45, 128.11, 127.16, 127.05, 125.26,
orated under reduced pressure to give 4.02 g of compound 22 123.92, 120.04, 119.57, 117.54, 110.79, 108.80, 54.08, 46.42,
(yield: 87%) as a white solid. 1H NMR (CDCl3, 500 MHz) d: 12.44 40.89, 30.69, 23.16, 23.01, 22.23, 20.97. ESI-MS (m/z): 438 [M +
(br s, 1H), 8.01 (s, 1H), 7.31 (dd, J ¼ 6.3, 1.2 Hz, 1H), 7.28–7.32 1]. Anal. calcd for C29H31N3O: C, 79.60; H, 7.14; N, 9.60. Found:
(m, 3H), 7.24 (d, J ¼ 6.6 Hz, 1H), 7.17 (d, J ¼ 6.6 Hz, 1H), 4.34 (s, C, 79.65; H, 7.12; N, 9.65%.
2H), 3.99 (t, J ¼ 7.0 Hz, 2H), 3.20 (br, 2H), 2.61–2.63 (m, 4H),
9-(3-(BENZYLAMINO)PROPYL)-N-(4-BROMOPHENYL)-2,3,4,9-TET-
1.75–1.82 (m, 6H), 1.32 (s, 9H). ESI-MS (m/z): 463 [M + 1]. Anal. RAHYDRO-1H-CARBAZOLE-6-CARBOXAMIDE (24E). Yellow oil: 0.28 g
calcd for C28H34N2O4: C, 72.70; H, 7.41; N, 6.06. Found: C, 72.67; (yield: 89%). 1H NMR (CDCl3, 500 MHz) d: 8.00 (s, 1H), 7.92
H, 7.45; N, 6.10%.
(s, 1H), 7.62 (d, J ¼ 8.5 Hz, 1H), 7.58 (d, J ¼ 8.7 Hz, 2H),
PHENYL 9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H- 7.46 (d, J ¼ 8.7 Hz, 2H), 7.27–7.34 (m, 7H), 4.14 (t, J ¼ 6.9
CARBAZOLE-6-CARBOXYLATE (24A). 1-(3-Dimethylaminopropyl)-3- Hz, 2H), 3.75 (s, 2H), 2.69–2.75 (m, 4H), 2.64 (t, J ¼ 6.6 Hz,
ethylcarbodiimide hydrochloride (EDC$HCl, 0.44 g, 2.25 mmol) 2H), 1.90–1.95 (m, 4H), 1.86–1.87 (br, 2H). 13C NMR (CDCl3,
and 4-dimethylamiopryidine (DMAP, 0.07 g, 0.6 mmol) were 125 MHz) d: 167.13, 139.82, 138.25, 137.78, 137.29, 131.84,
added to a solution of compound 22 (0.69 g, 1.5 mmol) and 128.48, 128.20, 127.17, 127.15, 124.83, 121.68, 119.59, 117.68,
phenol (0.28 g, 3.0 mmol) in CH2Cl2 (15 mL). The reaction 116.34, 110.85, 108.81, 53.96, 46.33, 40.86, 30.54, 23.13,
mixture was stirred at room temperature for 12 h. The mixture 22.98, 22.21, 20.94. ESI-MS (m/z): 517 [M + 1]. Anal. calcd for
was washed using saturated sodium carbonate (1 ꢃ 10 mL) and
C29H30BrN3O: C, 67.44; H, 5.85; N, 8.14. Found: C, 67.45; H,
brine (1 ꢃ 10 mL). The organic layer was dried over Na2SO4 and 5.90; N, 8.18%.
the solvent was evaporated under reduced pressure to give
N-BENZYL-9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-
crude product 23a, which was deprotected by HCl in EtOAc (1 1H-CARBAZOLE-6-CARBOXAMIDE (24F). Yellow oil: 0.22 g (yield:
mol Lꢀ1, 10 mL) to give 0.20 g of compound 24a (yield: 81%) as a 85%). 1H NMR (CDCl3, 500 MHz) d: 7.97 (d, J ¼ 1.5 Hz, 1H), 7.60
yellow oil. 1H NMR (CDCl3, 500 MHz) d: 8.41 (s, 1H), 8.00 (dd, J (dd, J ¼ 2.4, 1.5 Hz, 1H), 7.27–7.43 (m, 10H), 6.47 (t, J ¼ 5.1 Hz,
¼ 8.7, 1.2 Hz, 1H), 7.44 (t, J ¼ 7.8 Hz, 2H), 7.25–7.39 (m, 9H), 1H), 4.70 (s, 2H), 4.15 (t, J ¼ 6.9 Hz, 2H), 3.75 (s, 2H), 2.69–2.75
4.18 (t, J ¼ 7.0 Hz, 2H), 3.77 (s, 2H), 2.72–2.79 (m, 4H), 2.67 (t, J (m, 4H), 2.64 (t, J ¼ 6.9 Hz, 2H), 1.84–1.96 (m, 6H). ESI-MS (m/z):
¼ 6.8 Hz, 2H), 1.87–1.99 (m, 6H). ESI-MS (m/z): 439 [M + 1]. Anal. 452 [M + 1]. Anal. calcd for C30H33N3O: C, 79.79; H, 7.37; N, 9.30.
calcd for C29H30N2O2: C, 79.42; H, 6.89; N, 6.39. Found: C, 79.40; Found: C, 79.75; H, 7.39; N, 9.26%.
H, 6.82; N, 6.35. The synthetic method for compound 24b–g was
similar to that of compound 24a.
CYCLOHEXYL 9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-
1H-CARBAZOLE-6-CARBOXYLATE (24G). Yellow oil: 0.29 g (yield:
PIPERIDIN-4-YL-9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRA- 90%). 1H NMR (CDCl3, 500 MHz) d: 7.88 (s, 1H), 7.53 (d, J ¼ 7.5
HYDRO-1H-CARBAZOLE-6-CARBOXYLATE (24B). Yellow oil: 0.18 g Hz, 1H), 7.23–7.33 (m, 7H), 6.00 (d, J ¼ 7.8 Hz, 1H), 4.12 (t, J ¼
(yield: 80%). 1H NMR (CDCl3, 500 MHz) d: 8.21 (s, 1H), 7.84 6.8 Hz, 2H), 4.00–4.04 (m, 1H), 3.74 (s, 2H), 2.68–2.74 (m, 4H),
(dd, J ¼ 8.6, 1.4 Hz, 1H), 7.26–7.34 (m, 6H), 5.17 (br, 1H), 2.62 (t, J ¼ 6.7 Hz, 2H), 2.05–2.07 (m, 2H), 1.90–1.93 (m, 4H),
4.14 (t, J ¼ 6.9 Hz, 2H), 3.74 (s, 2H), 3.19–3.22 (m, 2H), 2.87– 1.83–1.86 (m, 2H), 1.74–1.77 (m, 2H), 1.60–1.62 (m, 2H), 1.40–
2.91 (m, 2H), 2.76 (br, 2H), 2.69–2.70 (m, 2H), 2.63 (t, J ¼ 6.6 1.44 (m, 2H), 1.25–1.28 (m, 2H). 13C NMR (CDCl3, 125 MHz) d:
Hz, 2H), 2.07 (br, 2H), 1.81–1.94 (m, 8H). 13C NMR (CDCl3, 167.91, 139.76, 137.92, 136.79, 128.45, 128.21, 127.12, 125.65,
125 MHz) d: 167.24, 140.19, 138.85, 136.87, 128.43, 128.12, 119.41, 117.15, 110.67, 108.47, 53.92, 48.52, 46.35, 40.83, 33.45,
127.03, 126.97, 122.05, 120.80, 120.66, 111.07, 108.29, 69.88, 30.51, 25.73, 25.00, 23.05, 22.25, 21.01. ESI-MS (m/z): 452 [M +
54.07, 46.43, 43.81, 40.88, 31.98, 30.66, 29.68, 29.34, 23.16, 1]. Anal. calcd for C29H36N2O2: C, 78.34; H, 8.16; N, 6.30. Found:
22.99, 22.20, 20.96, 14.09. ESI-MS (m/z): 446 [M + 1]. Anal. C, 78.30; H, 8.19; N, 6.26%.
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(9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-CARBA-
ZOL-6-YL)(PYRIDIN-2-YL)METHANONE (27A). Yellow oil: 0.14 g (yield:
87%). 1H NMR (CDCl3, 500 MHz) d: 8.73 (d, J ¼ 4.5, 1H), 8.23 (d,
J ¼ 1.5 Hz, 1H), 7.90 (d, J ¼ 10.9 Hz, 1H), 7.86 (dd, J ¼ 9.0, 1.4 Hz,
2H), 7.31 (t, J ¼ 6.8 Hz, 1H), 7.24–7.29 (m, 6H), 4.13 (t, J ¼ 6.9 Hz,
2H), 3.73 (s, 2H), 2.67–2.72 (m, 4H), 2.62 (t, J ¼ 6.7 Hz, 2H), 1.88–
1.93 (m, 4H), 1.81–1.84 (m, 2H). 13C NMR (CDCl3, 125 MHz) d:
194.21, 156.94, 148.40, 147.52, 136.94, 136.64, 128.39, 128.11,
127.00, 125.23, 124.42, 123.80, 122.96, 111.64, 108.39, 53.97,
46.30, 40.81, 30.57, 23.10, 22.92, 22.14, 20.93. ESI-MS (m/z): 424
[M + 1]. Anal. calcd for C28H29N3O: C, 79.40; H, 6.90; N, 9.92.
Found: C, 79.44; H, 6.88; N, 9.89%. The synthetic method for
compounds 27b and 27c was similar to that of compound 27a.
(9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-CARBA-
ZOL-6-YL)(5-METHYLPYRIDIN-2-YL)METHANONE (27B). Yellow oil:
TERT-BUTYL BENZYL(3-(6-(MORPHOLINE-4-CARBONYL)-3,4-DIHY-
DRO-1H-CARBAZOL-9(2H)-YL)PROPYL) CARBAMATE (25). EDC$HCl
(0.67 g, 3.40 mmol) and DMAP (0.11 g, 0.91 mmol) were
added to a solution of compound 22 (1.05 g, 2.27 mmol) and
morpholine (0.40 g, 4.54 mmol) in CH2Cl2 (25 mL), and the
resulting mixture was stirred at room temperature for 12 h.
The mixture was washed with saturated sodium carbonate (1
ꢃ 20 mL) and brine (1 ꢃ 20 mL). The organic layer was dried
over Na2SO4 and the solvent was evaporated under reduced
pressure to give compound 25 (0.86 g, yield 71%) as a yellow
1
solid. H NMR (CDCl3, 500 MHz) d: 7.56 (s, 1H), 7.25–7.29 (m,
4H), 7.12–7.18 (m, 4H), 4.37 (br, 2H), 3.95 (br, 2H), 3.70 (br,
8H), 3.28 (br, 2H), 2.69 (t, J ¼ 5.8 Hz, 2H), 2.59 (br, 2H), 1.83–
1.91 (m, 6H), 1.45 (s, 9H). ESI-MS (m/z): 532 [M + 1]. Anal.
calcd for C32H41N3O4: C, 72.29; H, 7.77; N, 7.90. Found: C,
72.30; H, 7.81; N, 7.88%.
1
0.17 g (yield: 89%). H NMR (CDCl3, 500 MHz) d: 8.55 (s, 1H),
8.22 (s, 1H), 7.86–7.89 (m, 2H), 7.66 (d, J ¼ 6.8 Hz, 1H), 7.24–7.32
(m, 6H), 4.13 (t, J ¼ 6.9 Hz, 2H), 3.75 (s, 2H), 2.68–2.72 (m, 4H),
2.63 (t, J ¼ 6.7 Hz, 2H), 2.44 (s, 3H), 1.90–1.96 (m, 4H), 1.82–1.84
(m, 2H). ESI-MS (m/z): 438 [M + 1]. Anal. calcd for C29H31N3O: C,
79.60; H, 7.14; N, 9.60. Found: C, 79.66; H, 7.12; N, 9.68%.
(9-(3-(BENZYLAMINO)PROPYL)-2,3,4,9-TETRAHYDRO-1H-CARBA-
ZOL-6-YL)(THIAZOL-2-YL)METHANONE (27C). Yellow oil: 0.20 g (yield:
93%). 1H NMR (CDCl3, 500 MHz) d: 8.79 (d, J ¼ 1.5 Hz, 1H), 8.32
(dd, J ¼ 10.5, 1.7 Hz, 1H), 8.09 (d, J ¼ 3.1 Hz, 1H), 7.65 (d, J ¼ 3.1
Hz, 1H), 7.36 (d, J ¼ 8.7 Hz, 1H), 7.25–7.31 (m, 6H), 4.16 (t, J ¼
7.0 Hz, 2H), 3.75 (s, 2H), 2.70–2.80 (m, 4H), 2.64 (t, J ¼ 6.7 Hz,
2H), 1.87–1.95 (m, 4H), 1.85–1.87 (m, 2H). ESI-MS
(m/z): 431 [M + 1]. Anal. calcd for C26H27N3OS: C, 72.69; H, 6.34;
N, 9.78. Found: C, 72.71; H, 6.33; N, 9.75%.
TERT-BUTYL
BENZYL(3-(6-PICOLINOYL-3,4-DIHYDRO-1H-CARBA-
ZOL-9(2H)-YL)PROPYL) CARBAMATE (26A). To a stirring solution of 2-
bromopyridine (0.47 g, 3.0 mmol) and tetramethylethylenedi-
amine (0.45 mL, 3.0 mmol) in anhydrouꢁs THF (25 mL) was
added n-BuLi (1.8 mL, 4.5 mmol) at ꢀ78 C under a nitrogen
atmosphere, and the solution was stirred for 30 min.
Compound 25 (0.53 g, 1.0 mmol) in THF (5 mL) was added
dropwise to the solution. The mixture was stirred for 30 min
and the resulting mixture was quenched with saturated
ammonium chloride (15 mL) and extracted with EtOAc (3 ꢃ 50
mL). The combined organic layer was washed with brine (1 ꢃ
50 mL) and dried over Na2SO4. The solvent was evaporated
under reduced pressure and the crude product was puried by
silica gel column chromatography (hexane : EtOAc ¼ 5 : 1) to
give 0.20 g of compound 26a (yield: 39%) as a yellow oil. 1H
NMR (CDCl3, 500 MHz) d: 8.75 (dd, J ¼ 7.5, 1.5 Hz, 1H), 8.23 (d,
J ¼ 1.5 Hz, 1H), 7.95 (d, J ¼ 7.8 Hz, 1H), 7.85–7.96 (m, 2H), 7.44–
7.49 (m, 2H), 7.14–7.33 (m, 5H), 4.40 (s, 2H), 3.97 (br, 2H), 3.27–
3.29 (m, 2H), 2.68–2.72 (m, 2H), 2.57–2.59 (m, 2H), 1.82–1.92
(m, 6H), 1.49 (s, 9H). ESI-MS (m/z): 546 [M + 1]. Anal. calcd for
In vitro antifungal activity assays
In vitro antifungal activity of each compound was expressed as
the minimal inhibitory concentration (MIC) that achieved 80%
inhibition of the tested fungi. MIC values were measured by the
serial dilution method in 96-well microtest plates. Fluconazole
and benzofuran NMT inhibitors 1 (Fig. 1)13 were used as refer-
ence drugs. Test fungal strains were obtained from the ATCC or
were clinical isolates. The MIC determination was performed
according to the National Committee for Clinical Laboratory
Standards (NCCLS) recommendations. The detailed experi-
mental protocols can be found in our previous studies.26
C
33H37N3O3: C, 75.69; H, 7.12; N, 8.02. Found: C, 75.63; H, 7.18;
N, 8.00%. The synthetic method for compounds 26b and 26c
was similar to the synthesis of compound 26a.
TERT-BUTYL
BENZYL(3-(6-(5-METHYLPICOLINOYL)-3,4-DIHYDRO-
1H-CARBAZOL-9(2H)-YL) PROPYL)CARBAMATE (26B). Yellow oil: 0.25
g (yield: 46%). 1H NMR (CDCl3, 500 MHz) d: 8.56 (s, 1H), 8.22 (s,
1H), 7.87–7.89 (m, 2H), 7.66 (d, J ¼ 6.8 Hz, 1H), 7.24–7.31 (m,
6H), 4.40 (s, 2H), 3.97 (br, 2H), 3.28 (br, 2H), 2.69–2.73 (m, 2H),
2.59 (s, 2H), 2.46 (s, 3H), 1.82–1.90 (m, 6H), 1.47 (s, 9H). ESI-MS
(m/z): 560 [M + Na]. Anal. calcd for C34H39N3O3: C, 75.95; H,
7.31; N, 7.81. Found: C, 75.99; H, 7.38; N, 7.90%.
TERT-BUTYL BENZYL(3-(6-(THIAZOLE-2-CARBONYL)-3,4-DIHYDRO-
1H-CARBAZOL-9(2H)-YL) PROPYL)CARBAMATE (26C). Yellow oil: 0.31
g (yield: 53%). 1H NMR (CDCl3, 500 MHz) d: 8.79 (d, J ¼ 1.5 Hz,
1H), 8.32 (dd, J ¼ 10.5, 1.7 Hz, 1H), 8.09 (d, J ¼ 3.1 Hz, 1H), 7.65
(d, J ¼ 3.1 Hz, 1H), 7.29 (d, J ¼ 8.7 Hz, 1H), 7.17–7.28 (m, 6H),
4.38 (s, 2H), 3.97 (br, 2H), 3.28 (br, 2H), 2.75–2.78 (m, 2H), 2.59
(s, 2H), 1.83–1.93 (m, 6H), 1.46 (s, 9H). ESI-MS (m/z): 531 [M + 1].
Anal. calcd for C31H35N3O3S: C, 70.29; H, 6.66; N, 7.93. Found:
C, 70.32; H, 6.71; N, 7.88%.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (Grant no. 30973640), the 863 Hi-Tech
Program of China (Grant 2012AA020302), and Shanghai
Municipal Health Bureau (Grant XYQ2011038).
References
1 M. A. Pfaller and D. J. Diekema, Clin. Microbiol. Rev., 2007,
20, 133–163.
2 L. Ostrosky-Zeichner, A. Casadevall, J. N. Galgiani, F. C. Odds
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