A concise synthesis of N-substituted fagomine derivatives and the systematic exploration of their α-glycosidase inhibition

Article abstract of DOI:10.1016/j.ejmech.2014.03.004

A novel and concise scheme has been developed successfully for the syntheses of N-substituted fagomine derivatives. The transformation of lactone (2) to 1,5-diol (3) was carried on with high yield (93-95%). The cyclization of 4 to 5 is a high stereoselect

Full text of DOI:10.1016/j.ejmech.2014.03.004

European Journal of Medicinal Chemistry 77 (2014) 211e222
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
A concise synthesis of N-substituted fagomine derivatives and the
systematic exploration of their
a
-glycosidase inhibition
,
,
,
Fu-xiang Jiang a 1, Qiao-zhen Liu a 1, Dan Zhao b 1, Cui-ting Luo a, Cui-ping Guo a,
Wen-cai Ye a c, Cheng Luo b, Heru Chen a
,
,b,c,
*
a Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Huangpu Avenue West 601, Guangzhou 510632,
PR China
b State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
c Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A novel and concise scheme has been developed successfully for the syntheses of N-substituted fagomine
derivatives. The transformation of lactone (2) to 1,5-diol (3) was carried on with high yield (93e95%). The
cyclization of 4 to 5 is a high stereoselective reaction (de value > 98%). It is disclosed that bulky sub-
stituent at N atom of the piperidine decreases the inhibition activity except those substituents having the
Received 16 August 2013
Received in revised form
28 February 2014
Accepted 2 March 2014
Available online 3 March 2014
ability of solvation or forming disulfide bond with M444 at the active site of
a-glycosidase, which
enhance the interaction with enzyme. Compounds with S-configuration at C-3 show greater activity than
those with R-configuration. The structureeactivity relationship study is also supported by molecular
docking analysis.
Keywords:
Azasugars
Fagomine
Ó 2014 Elsevier Masson SAS. All rights reserved.
a
-glycosidase
Total synthesis
Molecular docking
1. Introduction
Polyhydroxyated piperidines (azasugars), which contain a ni-
trogen atom instead of oxygen atom in the pyran ring of a sugar,
a
-Glucosidases are membrane-bound enzymes of the GH31
have been identified as glycosidase inhibitors [3,4]. They have been
disclosed as effective therapeutic agents for a wide range of dis-
eases including diabetes [5], viral infection [6], tumor metastasis
family that hydrolyze larger carbohydrate molecules to glucose and
related monosaccharides [1]. It has been disclosed nowadays that
most of these enzymes are located in the brush border of the small
intestine involved in numerous fundamental biological process,
such as intestinal digestion, posttranslational processing of the
sugar chain of glycoproteins, quality-control systems in the endo-
plasmic reticulum (ER) and the ER-associated degradation (ERAD)
mechanism, and the lysosomal catabolism of glycoconjugates [2].
Therefore, it’s no problem to understand that inhibition of glyco-
sidases will bring about profound effects on carbohydrate catabo-
lism in the intestines, maturation, transport, secretion of
glycoproteins, and can alter cellecell or cell-virus recognition
processes. Obviously, this is why glycosidase inhibitors show po-
tential applications in viral infection, cancer, and genetic disorder.
[7], and lysosomal storage disorder [8]. Two best-known a-gluco-
sidase inhibitors are acarbose and miglitol (Fig. 1). The first one is a
natural product isolated initially from an Actinoplanes strain, and
the last one is an N-hydroxyethyl analogue of 1-deoxynojirimycin
which was isolated from Morus spp. [1,9,10]. Unfortunately, either
acarbose or miglitol produces gastrointestinal complaints [1].
Hence, many efforts have been made to identify more effective a-
glycosidase inhibitors from natural sources in order to overcome
the exiting problem [11,12].
As azasugars, fagomine (Fig. 1) was first isolated from Japanese
buckwheat seeds (Fagopyrum esculentum Moench) [13] and sub-
sequently from the leaves of Morus multicaulis [14], which is pop-
ular in China. Another two epi-fagomines, 4-epi-fagomine and 3,4-
di-epi-fagomine (Fig. 1) were discovered from the leaves and roots
of the legume Xanthocersis zambesiaca [15]. These compounds have
been shown activity against mammalian gut a-glucosidase and b-
galactosidase [16,17]. Moreover, fagomine was found having potent
antihyperglycemic effect in streptozocin-induced diabetic mice and
* Corresponding author. Institute of Traditional Chinese Medicine and Natural
Products, College of Pharmacy, Jinan University, Huangpu Avenue West 601,
Guangzhou 510632, PR China.
E-mail address: thrchen@jnu.edu.cn (H. Chen).
These three authors contribute equally to this work.
1
http://dx.doi.org/10.1016/j.ejmech.2014.03.004
0223-5234/Ó 2014 Elsevier Masson SAS. All rights reserved.

212
F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
2. Chemistry
The total synthesis of fagomine derivatives was outlined in
Scheme 1. Both -glucal and -galactal were applied as the starting
materials in order to prepare epi-isomers at C-3 of the final prod-
ucts. Firstly, three hydroxyl groups of both -glucal and -galactal
D
D
D
D
were protected by benzyl groups using benzyl bromide/NaH/tet-
rabutylammonium iodide (TBAI) as the reagents. The addition of
TBAI, which was a phase transfer catalyst here, increased the yield
to 98.8%. Pyridiniumchlorochromate (PCC) was applied to oxidize
both 1-3S and 1-3R to lactones (2-3S and 2-3R) with yields from
72% to 83%. Two lactone isomers, 2-3S and 2-3R were reducted to
1,5-diols (3-3S and 3-3R) by LiAlH4 in high yields, which were from
95% to 93%. Both 1,5-diols (3-3S and 3-3R) were successfully turned
into ethyl 1,5-disulfonates (4-3S and 4-3R) applied ethylsulfonyl
chloride (EsCl) and Et3N as reagents. The yields were 72% and 82%
respectively. Reactions of ethyl 1,5-disulfonates with different pri-
mary amines resulted in the cyclized products 5a-s-3S and 5a-s-3R
with yields from good to excellence (70e93%). Removal of benzyl
group by Pd catalytic hydrogenation led to target products 6a-s-3S
and 6a-s-3R in mild to good yields (45e85%). In some cases, the low
yields were caused by the loss of product during HPLC purification.
The formation of piperidine derivatives (5a-s-3S and 5a-s-3R)
included two processes, an intermolecular SN2 reaction with pri-
mary amines following subsequently the intramolecular nucleo-
philic reaction. No 1,5-diamines were found although primary
amines were excessive during the reactions. This indicates that the
Fig. 1. Chemical structures of azasugars.
potentiating markedly the immunoreactive insulin release [18].
Interestingly, another fagomine isomer, the isofagomine was
confirmed as a potent liver glycogen phosphorylase (GP) inhibitors
[19]. All these facts make us believe that systematic exploration of
fagomine derivatives may possibly lead to the discovery of new
effective glycosidase inhibitors.
Therefore, in the current study, a concise total synthesis of N-
substituted fagomine derivatives has been developed. The sys-
tematic investigation of their a-glycosidase inhibition, structuree
activity relationship study, and molecular docking analysis were
also reported here.
Scheme 1. Synthesis of fagomine derivatives. Reagents and conditions: (a) THF, NaH, BnBr, TBAI, 98.8%; (b) DCM, PCC, 72e83%; (c) LiAlH4, THF, 93e95%; (d) DCM, Et3N, EsCl, 72e
82%; (e) dioxiane, 90e100 ꢀC, 70e93%; (f) H2, Pd/C, 0.2 M HCOOH, 45e85%.
Fig. 2. Putative mechanism for the formation of piperidine derivatives and the de values of some representative reaction. The de values were determined by HPLC analysis. Column:
chiral CD-Ph S5 (4.6 mm i.d.ꢁ250 mm); Eluant: ACN: 50 mM NaClO4 ¼ 60:40 (V:V); Flow rate: 0.5 ml/min; temperature: 30 ꢀC; Detector: UV 214 nm.

F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
213
Table 1
a
-Glucosidase inhibition of N-substituted fagomine derivatives.
Compounds
IC50
(
m
M) ꢂ SEM
Compounds
IC50
(
mM) ꢂ SEM
aAcarbose
6a-3S
6a-3R
6b-3S
6b-3R
6c-3S
6c-3R
6d-3S
6d-3R
6e-3S
6e-3R
6f-3S
39.8 ꢂ 0.3
6j-3S
161.2 ꢂ 0.6
141.2 ꢂ 0.5
235.2 ꢂ 2.1
184.2 ꢂ 1.6
186.0 ꢂ 0.7
166.0 ꢂ 0.7
e
124.5 ꢂ 1.5
6j-3R
6k-3S
6l-3S
110.0 ꢂ 0.8
e
e
6m-3S
6m-3R
6n-3S
6n-3R
6o-3S
6o-3R
6p-3S
6p-3R
6q-3S
6q-3R
6r-3S
6r-3R
6s-3S
e
e
e
e
e
170.2 ꢂ 1.3
158.8 ꢂ 2.2
168.1 ꢂ 0.6
151.9 ꢂ 0.4
151.7 ꢂ 0.5
147.4 ꢂ 0.7
217.0 ꢂ 1.2
203.7 ꢂ 2.3
121.9 ꢂ 0.9
e
e
e
6g-3S
6h-3S
6h-3R
6i-3S
215.9 ꢂ 2.1
e
e
216.2 ꢂ 1.5
139.3 ꢂ 1.1
6i-3R
IC50 values expressed as SEM (Standard Error of Mean), where n ¼ 3.
Fig. 3. Characteristic coupling constants of 4-3S and 5c-3S. ORTEP drawing of 6c-3S.
a
Positive control; e Less than 50% inhibition at 500 mM.
formation of piperidine derivatives is preferential absolutely to the
formation of 1,5-diamines.
3.2. Explanation from structure
Theoretically, as shown in Fig. 2, the intramolecular nucleophilic
reaction leads to the reverse of the configuration at C-1. This is true
in the current study. The optical analysis of all the resulted com-
pounds (5a-s-3S and 5a-r-3R) on chiral CD-Ph S5 column (SHI-
SEIDO CO., LTD, Japan) displayed that the stereoselectivities of all
the reactions were very high. All the de values were higher than
98%. Four representative examples were listed in Fig. 2. It can be
seen that more bulky of the substituent leads to higher stereo-
selectivity of the reaction. e.g., the de value of 5c-3S was greater
than that of 5k-3S due to p-OMePhCH2CH2 is a more bulky group
than AcNHCH2CH2. This is reasonable and complies obviously with
the law of SN2 reaction.
It was pointed out that the binding of acarbose at the active
site of -glycosidase involves numerous hydrogen bonds,
particularly with the acarvosine rings. Besides, hydrophobic in-
teractions also mediate binding of acarbose with the enzyme [20]
(Fig. 4A). As the same with acarbose, the molecular docking of
a
6a-3R to
a-glucosidase shows that 6a-3R locates at the inner
active site. It also forms strong hydrogen bonds and hydrophobic
interactions with surrounding residues of the enzyme (Fig. 4B).
When bulky substituents locate at the N atom of the piperidine
ring, steric clash tends to weaken the binding force of small
molecules with
a-glucosidase. This is in accordance with the
The configurations at C-1 of the domain products (5a-s-3S and
5a-r-3R) were confirmed reversed when compared with their
precursors (4-3S and 4-3R). e.g., as seen in Fig. 3, transformation of
4-3S to 5c-3S resulted in the reversed configuration at C-1 from R-
to S-, which was supported by the coupling constant of H-1 with H-
2. When single crystal of the compound is available, the configu-
ration is double supported by analysis of its X-ray data. As an
example, the configuration at C-1 of 6c-3S was confirmed S- which
supported the conclusion drawn from NMR analysis.
experimental results that from 6b to 6h all the activities
decrease. However, as shown in Fig. 4C, 6g-3S with 4-
sulphonamidophenethyl group at N atom could point out to the
solution environment. The sulfonamide group actually possesses
relative higher polarity and solvates in the solution more easily
when compared with other groups at compounds 6b-6h. The
solvation may compensate partially the loss of interaction caused
by steric clash. This may be the reason why 6g-3S has a relative
higher enzymatic activity.
Comparing the R- and S- configuration at C-3, it was found that
from R- to S- configuration the compounds flip to a position which
form more hydrogen bond interaction with surrounding residues of
the enzyme. This flip of conformation is particularly obvious in 6a,
6m and 6r (Fig. 5). The overall enhanced hydrogen bond interaction
may be the reason why compounds with S-configuration at C-3 are
always more active than those with R-configuration.
Interestingly, we found that the sulfur atom of 6s-3S has the
trend of forming disulfide bond with M444 of the enzyme (Fig. 6).
The disulfide bond may greatly strengthen the interaction between
6s-3S and the enzyme. Thus, 6s-3S shows greater activity than
either 6r-3S or 6r-3R and most of the other compounds.
3. Results and discussion
3.1.
a-Glycosidase inhibition of N-substituted fagomine derivatives
The
derivatives was determined by an in vitro screening assay. Acarbose
was chosen as the positive control. As shown in Table 1, the
a-glycosidase inhibition of all the N-substituted fagomine
a
-
glycosidase inhibition of all the tested fagomine derivatives was
less active than that of acarbose, and 1,2-di-epi-fagomine (6a-3R) is
the most active fagomine derivative. Any bulky substituents at N
atom of the piperidine ring (6b-6h, 6n) cause the loss of activity.
Only 6g-3S is the exception, which displays moderate activity with
IC50 value of 215.9 ꢂ 2.1
m
M. This indicates that the sulfamide group
4. Conclusions
possibly enhance the binding affinity with enzyme. As a universal
law amongst all the tested derivatives, compounds with R-config-
uration at C-3 are always less active than those with S-configura-
tion at C-3. It is quit interesting that 6s-3S shows greater activity
than either 6r-3S or 6r-3R. This evidence implies that sulfur in place
A series of N-substituted fagomine derivatives has been syn-
thesized by a novel and concise scheme. The transformation of
lactone (2) to 1,5-diol (3) was carried out easily in high yield (93e
95%). The cyclization of 4 to 5 includes the intermolecular nucle-
ophilic substitution (SN2) following immediately an intramolecular
nucleophilic substitution with high stereoselectivity (de
of oxygen at the same position results in higher affinity with a-
glycosidase.

214
F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
Fig. 4. Complex models of
a-Glucosidase with Acarbose (A), 6a-3R (B) and 6g-3S (C). Upper panel shows the structural electrostatic surfaces (the blue color indicates positive charge
and red color indicates negative charge). Water molecules are shown as red spheres. Acarbose, 6a-3R and 6g-3S are shown as sticks. Lower panel shows detailed interactions.
Residues which could form hydrogen bond with Acarbose, 6a-3R or 6g-3S are shown as green sticks and hydrophobic residues are shown as blue sticks. (For interpretation of the
references to colour in this figure legend, the reader is referred to the web version of this article.)
value > 98%). The inhibition of all the prepared compounds to
a
-
5. Experimental section
glycosidase has been systematically investigated. It is disclosed
that any bulky substitution at N atom of the piperidine basically
decreases the inhibition activity. Interestingly, compounds (6a, 6m
and 6r) with S-configuration at C-3 show greater inhibition ac-
tivity than those with R-configuration. Compounds with sub-
stituents having the ability of solvation (6g-3S) or forming
5.1. Materials and methods
5.1.1. Materials
Alpha-glucosidase (maltase) was purchased from ORIENTAL
YEAST Co. Ltd. (Japan). All other chemicals were purchased from
Aldrich or Adamas without further purification. Silica gel for col-
umn chromatography was purchased from Qingdao Marine
Chemicals Inc, China. Chromatographic grade methanol was
bought from Shandong YuWang Reagent Company (China).
disulfide bond with M444 of a-glycosidase (6s-3S) show greater
activity than those with bulky substituents only. The structuree
activity relationship study is supported by molecular docking
analysis.
Fig. 5. Comparison of detailed interactions between 6a-3R/S (Fig. A/B), 6m-3R/S (Fig. C/D) and 6r-3R/S (Fig. E/F). Residues which could form hydrogen bond with 6a-3R/S, 6m-3R/S
or 6r-3R/S are shown as green sticks and hydrophobic residues are shown as blue sticks. (For interpretation of the references to colour in this figure legend, the reader is referred to
the web version of this article.)

F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
215
5.1.2. General experimental procedures
the absorbance of p-nitrophenol at 400 nm on a microtitre plate
NMR spectra were recorded on Bruker AV-300 (Bruker Biospin,
Swiss), TMS was used as internal standard. ESI-MS were recorded
on Finnigan LCQ Advantage MAX mass spectrometer. HPLC was
performed on either LC-100 liquid chromatograph equipped with a
tunable LC-100 UV detector (Shanghai Wufeng Inc., China) or Agi-
lent 1200 series liquid chromatograph equipped with an Agilent
1200 Series UV detector (Agilent Technologies, USA). Column used
were Cosmosil 5C18 (Nacalai Tesque Inc., Japan) for general purifi-
cation and chiral CD-Ph S5 (SHISEIDO CO., LTD, Japan) for optical
analysis. Pre-coated thin-layer chromatography (TLC) plates
(Institute of Yantai Chemical Industry, China) were used for TLC.
Spots on TLC plates were detected by either a ZF-7A portable UV
detector or spraying Bismuth potassium iodide solution followed
subsequent heating. Ethanol was reluxed over Fresh magnesium
ribbon for 5 h and redistilled.
spectrophotometer (Spectra Max, Molecular Devices, USA). One
unit of a-glucosidase was defined as the amount of enzyme liber-
ating 1.0 mmol of p-nitrophenol per minute under the conditions
specified [24]. Acarbose was used as the positive control
(IC50 ¼ 39.75 ꢂ 0.06
mM) (Table 1). The percent inhibition of p-
nitrophenol formation in the test sample versus control was
calculated for each compound by using the following formula:
ꢀ
ꢁ
ODsample
ODcontrol
%inhibition ¼ 100 ꢄ
ꢁ 100
5.1.6. Statistical analysis
Results are presented as means ꢂ SEM from three experiments as
indicated in each figure legend. IC50 values were determined by using
EZ-FIT, Enzyme kinetics software by Perrella Scientific Inc., USA.
5.2. Synthetic process
5.1.3. X-ray crystallographic study
Data collections of compound 6c-3S were performed on a
5.2.1. Synthesis of (2R,3S,4R)-3,4-bis-benzyloxy-2-
benzyloxymethyl-3,4-dihydro-2H-pyran (1-3S)
Bruker Smart Apex CCD diffractometer with Mo-K
a radiation
ꢀ
ꢀ
(l
¼ 0.71073 A), using frames of 0.3 oscillation (2
q
ꢃ 56ꢀ). The
To a solution of D-glucal (1.46 g,10 mmol) in dry THF (20 ml) was
structures were solved with direct methods and refined with the
full-matrix least-squares technique with the SHELXTL programs.
Anisotropic thermal parameters were applied to all non-hydrogen
atoms. The hydrogen atoms were generated geometrically (Ce
added NaH (1.44 g, 60 wt% dispersion in mineral oil, 36 mmol) and
tetrabutylammonium iodide (TBAI) at room temperature. The
suspension was stirred for 30 min then cooled in an ice-bath.
Benzyl bromide (4.4 ml, 36 mmol) was added dropwise over a 5-
min period, and after 10 min the ice bath was removed. The reac-
tion mixture was stirred overnight. Then 10 ml of methanol was
added slowly to dispose the excess NaH. The solvents were
removed under reduced pressure at 35 ꢀC. The residue was then
dissolved in 200 ml of dichloromethane (DCM) and washed with
water and brine respectively. Then the mixture was dried over
anhydrous MgSO4. Removal of MgSO4 was carried on, and the
filtrate was evaporated to give a yellow oil, which solidified to a
yellow solid after submitted to high vacuum overnight. Further
purification by column chromatography (silica gel, EtOAc/Petro-
leum ether ¼ 1:20, V:V) gave 1-3S as a colorless semisolid (4.05 g,
ꢀ
H ¼ 0.960 A). The crystallographic calculations were conducted
with the SHELXL-97 programs [21].
5.1.4. Molecular docking
The N-substituted fagomine derivatives were docked to
a-
Glucosidase (PDB entry: 2QMJ) [20] using Glide program [22] in its
XP mode in a standard procedure. The three water molecules at the
active site were all retained. The N-substituted fagomine de-
rivatives were sketched by ChemBio3D Ultra 11.0 [23] and pro-
cessed by LigPrep under its default parameters. The docked
conformations of the compounds with the lowest energy were
selected for further analysis.
98.8%). 1H NMR (300 MHz, CDCl3)
d: 7.37e7.21 (m, 15H, Ph-H), 6.42
(dd, J ¼ 6.1, 1.2 Hz, 1H, H-6), 4.87 (dd, J ¼ 6.1, 2.7 Hz, 1H, H-5), 4.85e
4.50 (m, 6H, PhCH2e), 4.21 (ddd, J ¼ 6.1, 2.3, 1.4 Hz, 1H, H-2), 4.06
(m, 1H, H-7a), 3.86 (dd, J ¼ 8.7, 6.2 Hz,1H, H-4); 3.77 (m, 2H, H-3, H-
5.1.5. In vitro
-Glucosidase activity was assayed in 0.1 M sodium phosphate
buffer (pH 6.8) with p-nitrophenyl- -D-glucopyranoside as a sub-
strate. The concentration of -glucosidase was 0.2 U/mL in each
experiment. The enzyme (20 ml) along with 100 ml of phosphate
buffered saline was incubated with various concentrations of tested
compounds at 37 ꢀC. The pre-incubation time was 15 min, then
20 ml of substrate (0.7 mM) was added and reaction was carried on
at 37 ꢀC for 30 min. Enzymatic activity was quantified by measuring
a-glucosidase inhibition assay
a
a
7b); 13C NMR(75 MHz, CDCl3)
d: 144.8, 138.4, 138.3, 138.1, 128.5
a
(6C), 127.8 (3C), 127.7 (6C), 100.0, 76.8, 75.8, 74.5, 73.8, 73.6, 70.5,
68.6; ESI-MS (m/z): 439.4[M þ Naþ].
5.2.2. Synthesis of compounds (2R,3R,4R)-3,4-bis-benzyloxy-2-
benzyloxymethyl-3,4-dihydro-2H-pyran (1-3R)
Followed the process as described in 5.2.1.1. D-galactal (0.73 g,
5.0 mmol), NaH (1.8 g, 60 wt% dispersion in mineral oil, 75 mmol),
benzyl bromide (2.2 ml, 18 mmol) were added. No TBAI was added.
The final purification by column chromatography (silica gel, EtOAc/
Petroleum ether ¼ 1:10, V:V) gave 1-3R as a colorless solid (1.92 g,
92.3%). Rf ¼ 0.36; 1H NMR (300 MHz, CDCl3)
d: 7.20e7.30(m, 15H,
Ph-H), 6.33 (dd, J ¼ 6.2, 1.3 Hz, 1H), 4.80e4.84 (m, 2H), 4.34e
4.60(m, 6H), 4.10e4.17(m, 2H), 3.89 (m, 1H), 3.74e3.80 (m, 1H),
3.62e3.67 (m, 1H); 13C NMR (75 MHz, CDCl3)
d: 144.0, 138.4, 138.3,
137.9, 128.6 (6C), 127.7 (3C), 127.8 (6C), 99.9, 75.5, 73.3, 73.2, 71.2,
70.7, 70.6, 68.3; ESI-MS (m/z): 417.5[M þ H]þ.
5.2.3. Synthesis of (2R,3S,4R)-3,4-bis-benzyloxy-2-
benzyloxymethyl-tetrahydro-pyran-5-one (2-3S)
Fig. 6. Complex model of a-Glucosidase with 6s-3S. The structural electrostatic sur-
To a solution of 1-3S (4.1 g, 10 mmol) in DCM (25 ml), PCC
(12.9 g, 60 mmol) was added in portions following the addition of
about 5 g silica gel. The mixture was stirred at ambient temperature
for 12 h. Then the reaction mixture was submitted to a funnel filled
faces are shown as Fig. 3A. And detailed interactions are shown as Fig. 3B. Residues
which could form hydrogen bond with 6s-3S are shown as green sticks and hydro-
phobic residues are shown as blue sticks. (For interpretation of the references to colour
in this figure legend, the reader is referred to the web version of this article.)

216
F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
with diatomite for removal of silica gel and insoluble substances. All
the filtrates were combined, and the solvent was evaporated under
reduced pressure. The residue was further purified by column
chromatography (silica gel, EtOAc/Petroleum ether ¼ 1:4, V:V) to
then quenched with saturated Na2CO3 solution (10 ml) and
extracted with dichloromethane (3 ꢁ 50 ml). The combined organic
layer was washed with saturated sodium bicarbonate solution and
then with water. The organic layer was dried over anhydrous
MgSO4, filtered and concentrated. The residue was submitted to
column chromatography (silica gel, EtOAc/Petroleum ether ¼ 1:4,
V:V) led to 4-3S as a colorless oil (3.6 g, 82%). 1H NMR (300 MHz,
give 2-3S as a colorless oil (3.11 g, 72%). 1H NMR (300 MHz, CDCl3)
d:
7.33e7.16 (m, 15H, Ph-H), 4.64e4.42 (m, 6H, PhCH2e), 4.26 (m, 1H),
3.88 (m, 2H), 3.68 (m, 2H), 2.77 (m, 2H); 13C NMR(75 MHz, CDCl3)
d:
169.5, 137.9, 137.5 (2C), 128.6 (2C), 128.5 (2C), 128.2 (2C), 128.1 (3C),
127.9 (6C), 79.4, 75.2, 74.9, 73.6, 72.9, 71.1, 69.0, 33.8; ESI-MS (m/z):
455.3[M þ Naþ].
CDCl3)
d
: 7.40e7.23 (m, 15H, Ph-H), 4.96 (dt, J ¼ 6.4, 3.1 Hz, 1H),
4.81e4.44 (m, 6H, PhCH2e), 4.17 (m, 2H), 3.95 (dd, J ¼ 4.9, 2.9 Hz,
1H), 3.85 (m, 2H), 3.72 (dt, J ¼ 9.3, 4.6 Hz, 1H), 3.24e2.94 (m, 4H, e
CH2SO2e), 1.97 (m, 2H), 1.33 (m, 6H, CH3e); 13C NMR (75 MHz,
5.2.4. Synthesis of (2R,3R,4R)-3,4-bis-benzyloxy-2-
CDCl3) d: 137.7, 137.5, 137.4, 128.5 (2C), 128.4 (2C), 128.1 (2C), 128.0
benzyloxymethyl-tetrahydro-pyran-5-one (2-3R)
(3C), 127.9 (6C), 82.2, 80.0, 5.2, 74.3, 73.2, 73.1, 69.0, 66.3, 45.6, 44.8,
Followed the process as described in 5.2.2.1. 1-3R (1.6 g,
3.8 mmol) in DCM (20 ml), PCC (3.3 g, 15.4 mmol) and 3 g silica gel
were added. The final purification by column chromatography
(silica gel, EtOAc/Petroleum ether ¼ 1:1, V:V) gave 2-3R as a
30.8, 8.2 (2C); ESI-MS (m/z): 643.5[M þ Na]þ.
5.2.8. Synthesis of (2R,3S,4R)-1,3,4-tris(benzyloxy)hexane-2,5-
diethylsulfonate (4-3R)
colorless oil (1.4 g, 82.3%), Rf ¼ 0.34. 1H NMR (300 MHz, CDCl3)
d:
Followed the process as described in 5.2.4.1. 3-3R (1.35 g,
3.1 mmol) in DCM (20 ml), and Et3N (1.0 ml, 6.8 mmol), ethyl-
sulfonyl chloride (0.6 ml, 6.5 mmol) were added. The final purifi-
cation by column chromatography (silica gel, EtOAc/Petroleum
ether ¼ 1:3, V:V) gave 4-3R in slight yellow oil (1.39 g, 72.3%),
7.39e7.26 (m, 15H, AreH), 4.92 (d, J ¼ 11.5 Hz, 1H), 4.64e4.41 (m,
1H), 4.31 (ddd, J ¼ 7.6, 5.7, 1.6 Hz, 1H), 4.14 (m, 1H), 3.87e3.81 (m,
1H), 3.76e3.62(m, 2H), 3.00e2.82 (m, 2H); 13C NMR (75 MHz,
CDCl3) d: 169.0, 138.0, 137.5, 137.4, 128.6 (2C), 128.5 (2C), 128.2 (2C),
128.0 (3C),127.4 (6C), 78.1, 74.4, 74.2, 73.6, 70.7, 70.3, 67.9, 33.0; ESI-
Rf ¼ 0.30. 1H NMR (300 MHz, CDCl3)
d: 7.24e7.39 (m, 15H, AreH),
MS (m/z): 433.5 [M þ H]þ, 455.1 [M þ Na]þ.
4.82 (m, 2H), 4.64 (dd, J ¼ 11.3, 6.0 Hz, 2H), 4.49 (m, 3H), 4.32 (m,
2H), 4.01 (dd, J ¼ 5.6, 3.0 Hz, 1H), 3.82(m, 1H), 3.73 (d, J ¼ 4.7 Hz,
2H), 3.21e2.93 (m, 4H, eCH2SO2e), 2.04 (m, 2H), 1.31 (m, 6H, CH3e
5.2.5. Synthesis of (2R,3R,4R)-1,3,4-tris(benzyloxy)hexane-2,5-diol
(3-3S)
); 13C NMR (75 MHz, CDCl3)
d: 138.1, 138.0, 137.5, 128.8 (2C), 128.6
To a solution of 2-3S (3 g, 7 mmol) in anhydrous THF (25 ml),
LiAlH4 (2.2 g, 60 mmol) was added in portions with stirring in an
ice-water bath. After the completion of the addition, the mixture
was stirred for another 2 h at ambient temperature. The excess
hydride was destroyed by addition of 2 mol/L HCl in ice-water bath
until no gas was observed. The reaction mixture was extracted with
EtOAc (4 ꢁ 100 mL). The combined organic layers were washed
with water and brine respectively, and were dried over anhydrous
MgSO4. After removal of the solvent, the residue was purified by
column chromatography (silica gel, EtOAc/Petroleum ether ¼ 1:3,
V:V) to give 3-3S as a colorless oil (3.6 g, 95%). 1H NMR(300 MHz,
(2C), 128.5 (2C), 128.1 (3C), 127.9 (6C), 81.2, 78.6, 75.7, 74.7, 73.9,
72.5, 69.6, 67.0, 46.1, 45.1, 30.8, 8.4 (2C); ESI-MS (m/z): 643.1
[M þ Na]þ.
5.2.9. General procedure for the syntheses of 5a-s-3S and 5a-r-3R
Either 4-3S or 4-3R [(310.1 mg, 0.5 mmol), ortherwise marked
out] and amines (3e5 ml) were sealed together in a dried 10-ml
pressure reactor. The reaction mixture was stirred at 80e90 ꢀC
over an oil-bath for scheduled time (12e18 h). Then, the mixture
was quenched with 8 ml of 1.0 mol/L hydrochloric acid and
extracted with dichloromethane (3 ꢁ 50 ml). The combined organic
layer was washed with saturated sodium bicarbonate solution and
water respectively. The organic layer was then dried over anhy-
drous MgSO4, filtered and concentrated. The residues were sub-
mitted to column chromatography (silica gel, EtOAc/Petroleum
ether) or RP-HPLC for purification.
CDCl3)
1H), 3.86 (m, 1H), 3.73e3.53 (m, 4H), 3.42 (dd, J ¼ 9.1, 9.3 Hz, 1H),
1.87 (m, 2H); 13C NMR(75 MHz, CDCl3)
: 138.1, 138.0, 137.8, 128.6,
d: 7.39e7.21 (m, 15H, Ph-H), 4.57 (m, 6H, PhCH2e), 4.01 (m,
d
128.5, 128.4, 128.3, 128.2, 128.1, 127.9 (3C), 127.8 (6C), 78.5, 77.9,
73.7, 73.6, 72.8, 71.3, 70.8, 59.8, 33.0; ESI-MS (m/z): 459.3[M þ Na]þ.
5.2.6. Synthesis of (2R,3S,4R)-1,3,4-tris(benzyloxy)hexane-2,5-diol
(3-3R)
5.2.9.1. Synthesis of (2S,3R,4R)-3,4-bis(benzyloxy)-2-(benzylox-
ymethyl)-1-(furan-2-ylmethyl)piperidine (5a-3S). Purified by silica
gel column chromatography (EtOAc/Petroleum ether, 1:4, V:V) to
afford 5a-3S as slight yellow oil (218.7 mg, 88%). 1H NMR (300 MHz,
Followed the process as described in 5.2.3.1. 2-3R (1.5 g,
3.4 mmol) in DCM (15 ml), and LiAlH4 (1.02 g, 26.8 mmol) were
added. The final purification by column chromatography (silica gel,
EtOAc/Petroleum ether ¼ 1:1, V:V) gave 3-3R in slight yellow oil
CDCl3)
d
: 7.39e7.20 (m,16H, AreH), 6.28 (dd, J ¼ 3.1,1.9 Hz,1H), 6.14
(d, J ¼ 3.1 Hz, 1H), 4.65e4.43 (m, 6H, PhCH2e), 3.93e3.64 (m, 5H),
3.49 (m, 1H), 3.22 (dd, J ¼ 9.8, 4.4 Hz, 1H), 2.61 (m, 2H), 1.97 (m, 1H),
(1.14 g, 78.2%), Rf ¼ 0.23. 1H NMR (300 MHz, CDCl3)
d: 7.23e7.29 (m,
15H), 4.40e4.75 (m, 6H), 3.86 (m, 1H), 3.68e3.54 (m, 4H), 3.50 (d,
1.63 (m, 1H); 13C NMR(75 MHz, CDCl3)
d: 152.5, 141.9, 139.0, 138.7,
J ¼ 5.7, 5.3 Hz, 1H), 1.86 (m, 2H); 13C NMR (75 MHz, CDCl3)
d: 138.2,
138.5,128.4,128.3,128.2 (4C),127.7 (2C),127.6 (2C),127.4 (3C),110.1,
108.7, 78.2, 74.3, 72.8, 71.1, 70.2, 67.6, 59.2, 50.9, 45.8, 27.6; ESI-MS
(m/z): 498.5[M þ H]þ.
138.1, 138.0, 128.7, 128.6, 128.5, 128.4, 128.3, 128.2, 127.9 (3C), 127.5
(6C), 79.4, 78.0, 74.0, 73.5, 72.6, 71.2, 70.2, 59.6, 33.6,; ESI-MS (m/z):
459.3[M þ Na]þ.
5.2.9.2. Synthesis of (2S,3S,4R)-3,4-bis(benzyloxy)-2-(benzylox-
ymethyl)-1-(furan-2-ylmethyl)piperidine (5a-3R). Purified by RP-
HPLC (methanol:H2O ¼ 4:1, V:V) to give 5a-3R as slight yellow oil
5.2.7. Synthesis of (2R,3R,4R)-1,3,4-tris(benzyloxy)hexane-2,5-
diethylsulfonate (4-3S)
3-3S (3 g, 7 mmol) was dissolved in 25 ml of dried dichloro-
methane and dried over molecular sieves in order to remove any
moisture if present. Triethylamine (1.2 ml, 7.2 mmol) was then
added and the reaction mixture was cooled to 0 ꢀC. After 5 min,
ethylsulfonyl chloride (1.35 ml, 14.7 mmol) was added and the re-
action mixture was stirred for 3 h at 0 ꢀC. The reaction mixture was
(221.7 mg, 89.2%). 1H NMR (300 MHz, CDCl3)
d: 7.18e7.36 (m, 16H),
6.24 (dd, J ¼ 3.1, 1.9 Hz, 1H), 6.07 (d, J ¼ 3.1 Hz, 1H), 4.44e4.58 (m,
5H), 4.33 (d, J ¼ 11.6 Hz, 1H), 3.76e3.85 (m, 5H), 3.64 (dd, J ¼ 9.2,
2.8 Hz,1H), 2.85 (m, 1H), 2.64 (m, 2H),1.90 (m, 1H), 1.60 (m, 1H); 13
C
NMR (75 MHz, CDCl3)
d: 151.8, 141.6, 138.5,138.1, 138.0,128.3, 128.2,
128.1 (4C), 127.5 (2C), 127.3 (2C), 127.1 (3C), 109.7, 108.6, 76.8, 73.2,

F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
217
71.2, 70.7, 70.2, 65.5, 58.8, 49.2, 46.1, 26.9; ESI-MS (m/z): 498.4
[M þ H]þ, 520.3 [M þ Na]þ.
5.2.9.8. Synthesis of (2S,3S,4R)-1-(4-fluorophenethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5d-3R).
Purified by RP-HPLC (methanol:H2O ¼ 17:3, V:V) to give 5d-3R as
slight yellow oil (246.9 mg, 91.6%). 1H NMR (300 MHz, CDCl3)
d:
5.2.9.3. Synthesis of (2S,3R,4R)-3,4-bis(benzyloxy)-2-(benzylox-
ymethyl)-1-phen-ethylpiperidine (5b-3S). Purified by silica gel col-
umn chromatography (EtOAc/Petroleum ether, 1:4, V:V) to afford
5b-3S as slight yellow oil (234.5 mg, 90%). 1H NMR (300 MHz,
7.24e7.36 (m, 15H), 6.86e6.98 (m, 4H), 4.53e4.65 (m, 4H), 4.41(dd,
J ¼ 11.9, 7.1 Hz, 2H), 3.85 (s, 1H), 3.60e3.72 (m, 3H), 2.99 (d,
J ¼ 8.9 Hz, 1H), 2.62e2.88 (m, 6H), 1.97 (m, 1H), 1.65 (ddd, J ¼ 11.8,
9.7, 2.5 Hz, 1H),; 13C NMR (75 MHz, CDCl3)
d: 160.7, 139.0, 138.5,
CD3COCD3) d: 7.42e7.19 (m, 20H, AreH), 4.65 (s, 2H, PhCH2e), 4.63
138.0, 136.3, 130.0, 127.42e128.37(16C), 115.2, 114.9, 76.9, 73.5, 71.6,
71.5, 70.8, 65.1, 59.1, 55.4, 46.2, 30.5, 27.4; ESI-MS (m/z): 540.5
[M þ H]þ, 562.5[M þ Na]þ.
(s, 2H, PhCH2e), 4.50 (s, 2H, PhCH2e), 3.86 (m, 1H), 3.74 (m, 1H),
3.63 (m, 2H), 3.45 (m, 1H), 2.93e2.61 (m, 6H), 2.01 (m, 1H), 1.59 (m,
1H); 13C NMR(75 MHz, CD3COCD3)
d: 141.9, 140.5, 140.2, 139.8,
129.7 (2C), 129.1 (2C), 129.0 (2C), 129.0 (2C), 128.5 (2C), 128.4 (2C),
128.2 (2C), 128.1 (2C), 128.0 (3C), 126.5, 80.2, 75.7, 72.8, 72.2, 71.0,
66.3, 59.7, 56.5, 45.5, 33.6, 29.0; ESI-MS (m/z): 522.5[M þ H]þ.
5.2.9.9. Synthesis of (2S,3R,4R)-1-(3-fluorophenethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5e-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:4, V:V)
to afford 5e-3S as slight yellow oil (212.9 mg, 77%). 1H NMR
5.2.9.4. Synthesis of (2S,3S,4R)-3,4-bis(benzyloxy)-2-(benzylox-
ymethyl)-1-phen-ethylpiperidine (5b-3R). Purified by RP-HPLC
(methanol:H2O ¼ 17:1, V:V) to give 5b-3R as slight yellow oil
(300 MHz, CDCl3) d: 7.40e6.88 (m, 19H, Ph-H), 4.66e4.35 (m, 6H,
PhCH2e), 3.75 (m, 1H), 3.61 (m, 2H), 3.49 (m, 1H), 3.30 (m, 1H),
3.07e2.70 (m, 6H), 1.97 (m, 1H), 1.65 (m, 1H); 13C NMR (75 MHz,
(219.6 mg, 84.3%). 1H NMR (300 MHz, CDCl3)
d: 7.19e7.36 (m, 18H),
CDCl3) d: 162.8, 143.5, 138.9, 138.6, 138.4, 131.1, 128.3 (3C), 128.1
7.03 (m, 2H), 4.50e4.84 (m, 4H), 4.39(d, J ¼ 8.9 Hz, 2H), 3.84 (m,
(3C), 127.6 (3C), 127.5 (2C), 127.4 (2C), 127.4 (2C), 123.8, 115.2, 114.9,
78.7, 74.7, 73.4, 72.7, 71.4, 67.8, 59.3, 54.9, 46.0, 28.1, 25.9; ESI-MS
(m/z): 540.5 [M þ H]þ.
1H), 3.62e3.74 (m, 3H), 3.00 (d, J ¼ 12.0 Hz, 1H), 2.64e2.75 (m, 6H),
1.96 (m, 1H),1.66 (m, 1H); 13C NMR (75 MHz, CDCl3)
d: 140.6, 138.9,
138.4, 138.0, 128.5 (2C), 128.2 (2C), 128.1 (2C), 128.0 (2C), 127.5 (2C),
127.4 (2C), 127.2 (2C), 127.1 (2C), 127.0 (3C), 125.8, 73.4, 71.4, 71.3,
70.7, 65.4, 55.3, 58.9, 50.3, 46.1, 31.1, 27.3; ESI-MS (m/z): 522.4
[M þ H]þ, 544.5[M þ Na]þ.
5.2.9.10. Synthesis of (2S,3S,4R)-1-(3-fluorophenethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl)
Purified by RP-HPLC (methanol:H2O ¼ 17:3, V:V) to give 5d-3R as
slight yellow oil (262.9 mg, 95.1%). 1H NMR (300 MHz, CDCl3)
piperidine
(5e-3R).
d:
5.2.9.5. Synthesis of (2S,3R,4R)-1-(4-methoxyphenethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5c-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:4, V:V)
to afford 5c-3S as faint yellow oil (246.0 mg, 89%). 1H
7.28e7.41 (m, 15H), 6.90e7.03 (dt, J ¼ 22.2, 8.5 Hz, 4H), 4.57e4.70
(m, 4H), 4.43 (dd, J ¼ 11.9, 7.9 Hz, 2H), 3.89 (s, 1H), 3.65e3.76 (m,
3H), 3.03 (d, J ¼ 8.7 Hz, 1H), 2.66e2.92 (m, 6H), 2.01 (dd, J ¼ 13.8,
3.6 Hz, 1H), 1.69 (m, 1H); 13C NMR (75 MHz, CDCl3)
d: 160.8, 139.0,
NMR(300 MHz, CD3COCD3) d: 7.42e7.19 (m, 15H, AreH), 7.11 (m,
138.5, 138.0, 136.3, 130.0, 127.42e128.37(16C), 115.18, 114.90, 76.9,
73.5, 71.6, 71.5, 70.8, 65.7, 59.1, 55.4, 46.2, 30.5, 27.4; ESI-MS (m/z):
540.5 [M þ H]þ, 562.5[M þ Na]þ.
2H, AreH), 6.80 (m, 2H, AreH), 4.65 (s, 2H, PhCH2e), 4.63(s, 2H,
PhCH2e), 4.50 (s, 2H, PhCH2e), 3.83 (m, 1H), 3.73 (s, 3H, CH3Oe),
3.71 (m, 1H), 3.61 (m, 2H), 3.45 (m, 1H), 2.98e2.61 (m, 6H), 1.98 (m,
1H), 1.56 (m, 1H); 13C NMR (75 MHz, CD3COCD3)
d: 158.9, 139.7,
5.2.9.11. Synthesis of (2S,3R,4R)-1-(2-(1H-imidazol-4-yl)ethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5f-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:2, V:V)
to afford 5f-3S as slight yellow oil (178.9 mg, 70%). 1H NMR
139.3, 139.0, 132.9, 129.7 (2C), 128.2 (3C), 128.1 (3C), 127.6 (3C),
127.5 (2C), 127.4 (2C), 127.3, 127.1, 113.5 (2C), 81.1, 78.6, 73.5, 72.8,
71.9, 67.2, 60.8, 57.5, 55.4, 46.5, 33.6, 28.9; ESI-MS (m/z): 552.4
[M þ H]þ.
(300 MHz, CDCl3) d: 9.10 (s, 1H, eNHe), 7.47e7.24 (m, 15H, Ph-H),
6.80 (m, 2H), 4.77e4.43 (m, 6H, PhCH2e), 3.72 (m, 4H), 3.30 (m,
1H), 2.97e2.60 (m, 6H), 2.01 (m, 1H), 1.78 (m, 1H); 13C NMR
5.2.9.6. Synthesis of (2S,3S,4R)-1-(4-methoxyphenethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5c-3R). Purified by
RP-HPLC (methanol:H2O ¼ 4:1, V:V) to give 5c-3R as colorless oil
(75 MHz, CDCl3) d: 138.7, 138.3, 137.8, 134.3, 131.4, 128.6 (2C), 128.4
(2C), 128.1, 128.0, 127.6 (3C), 127.5 (6C), 122.6, 74.6, 73.5, 73.1, 71.4,
(270.9 mg, 98%). 1H NMR (300 MHz, CDCl3)
d: 7.21e7.36 (m, 15H),
68.4, 60.3, 53.5, 52.3, 44.5, 26.9, 22.6; ESI-MS (m/z): 512.5[M þ H]þ.
6.96 (d, J ¼ 8.6 Hz, 2H), 6.75 (d, J ¼ 2.8 Hz, 2H), 4.38e4.64 (m, 6H),
3.84 (m, 1H), 3.74 (s, 3H), 3.61e3.71 (m, 3H), 2.99 (d, J ¼ 8.9 Hz, 1H),
2.84 (m, 3H), 2.67 (dd, J ¼ 13.2, 5.9 Hz, 3H), 1.96(m, 1H), 1.66 ( ddd,
5.2.9.12. Synthesis of (2S,3R,4R)-1-(4-sulphonamidophenethyl)-3,4-
bis(benzyloxy)-2
-(benzyloxy
methyl)
piperidine
(5g-3S).
J ¼ 11.8, 9.7, 2.4 Hz, 1H); 13C NMR (75 MHz, CDCl3)
d: 157.9, 139.0,
Purified by silica gel column chromatography (EtOAc/Petroleum
ether, 1:3, V:V) to afford 5g-3S as slight yellow oil (195.0 mg, 65%).
138.5,138.1, 132.7, 129.6 (2C), 128.6 (3C), 128.5 (3C),127.6 (3C), 127.5
(2C), 127.4 (2C), 127.3, 127.2, 113.8 (2C), 77.0, 73.6, 71.6, 71.5, 70.8,
65.6, 59.1, 55.6, 55.3, 46.3, 30.4, 27.4; ESI-MS (m/z):552.5 [M þ H]þ.
1H NMR (300 MHz, CDCl3)
d: 7.73e7.07 (m, 19H, Ph-H), 4.64e4.32
(m, 6H, PhCH2e), 3.72 (dd, J ¼ 10.0, 6.4 Hz, 1H), 3.60 (m, 1H), 3.51
(m, 2H), 3.23 (m, 1H), 2.93e2.53 (m, 6H), 1.97 (m, 1H), 1.67 (m, 1H);
5.2.9.7. Synthesis of (2R,3R,4R)-1-(4-fluorophenethyl)-3,4-
13C NMR (75 MHz, CDCl3)
d: 146.3, 139.7, 138.8, 138.4, 138.2, 128.5
bis(benzyloxy)-2-
(benzyloxymethyl)
piperidine
(5d-3S).
(2C), 128.4 (2C), 128.3 (2C), 128.1 (2C), 127.9 (3C), 127.8 (2C), 127.7
(2C), 127.5 (2C), 126.4 (2C), 78.2, 73.9, 73.4, 72.7, 71.3, 68.5, 58.8,
55.8, 45.9, 31.7, 27.5; ESI-MS (m/z): 601.4[M þ H]þ.
Purified by silica gel column chromatography (EtOAc/Petroleum
ether, 1:4, V:V) to afford 5d-3S as slight yellow oil (218.3 mg, 81%).
1H NMR (300 MHz, CDCl3)
d: 7.52e6.90 (m, 19H, AreH), 4.81e4.48
(m, 6H, PhCH2e), 3.89 (m, 1H, H-7a), 3.74 (ddd, 1H, J ¼ 13.5, 8.2,
5.2.9.13. Synthesis of (2S,3R,4R)-1-(4-methylphenethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5h-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:4, V:V)
to afford 5h-3S as slight yellow oil (246.6 mg, 92%). 1H NMR
3.8 Hz), 3.64 (m, 2H), 3.44 (m, 1H), 3.07e2.70 (m, 6H), 2.12 (m, 1H),
1.80 (m, 1H); 13C NMR (75 MHz, CDCl3)
d: 162.7, 138.8, 138.5, 138.2,
136.3,129.9 (2C),128.2 (3C),128.2 (3C),128.0 (3C),127.7,127.5,127.4
(2C), 127.3 (2C), 114.9, 114.6, 78.7, 74.6, 73.4, 72.7, 71.4, 67.9, 59.2,
55.6, 46.1, 31.6, 28.1; ESI-MS (m/z): 540.5 [M þ H]þ.
(300 MHz, CDCl3)
d: 7.45e7.15 (m, 15H, Ph-H), 7.00 (q, J ¼ 8.0 Hz,
4H, AreH), 4.70e4.35 (m, 6H, PhCH2e), 3.77 (dd, J ¼ 9.8, 6.0 Hz,1H),

218
F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
3.62 (m, 2H), 3.51 (m, 1H), 3.30 (m, 1H), 2.76 (m, 6H), 2.29 (s, 3H,
CH3e), 1.95 (m, 1H), 1.67 (m, 1H); 13C NMR (75 MHz, CDCl3)
: 139.1,
138.8, 138.5, 137.7, 135.3, 129.1 (2C), 128.8 (3C), 128.3 (3C), 127.8
(3C), 127.6 (2C), 127.5 (2C), 127.1 (2C), 127.0 (2C), 78.4, 74.5, 73.4,
72.8, 71.4, 67.8, 59.2, 56.7, 46.2, 31.9, 28.0, 21.2; ESI-MS (m/z): 536.4
[M þ H]þ.
5.2.9.19. Synthesis of (2S,3R,4R)-1-(20-acetlyaminoethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5k-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:2, V:V)
to afford 5k-3S as slight yellow oil (208.3 mg, 83%). 1H NMR
d
(300 MHz, CDCl3) d: 7.41e7.21 (m, 15H, AreH), 6.97 (s, 1H, eCONHe
), 4.71e4.46 (m, 6H, PhCH2e), 3.78 (dd, J ¼ 10.1, 7.5 Hz), 3.60 (m,
3H), 3.33 (m, 3H), 2.84 (m, 2H), 2.70 (m, 2H), 1.97 (m, 1H), 1.65 (m,
5.2.9.14. Synthesis of (2S,3S,4R)-1-(4-methylphenethyl)-3,4-
1H); 13C NMR (75 MHz, CDCl3)
d: 170.4, 138.7, 138.4, 138.1, 128.5
bis(benzyloxy)-2-
Purified by RP-HPLC (methanol:H2O ¼ 17:3, V:V) to give 5h-3R as
slight yellow oil (240.2 mg, 89.6%). 1H NMR (300 MHz, CDCl3)
(benzyloxymethyl)
piperidine
(5h-3R).
(3C), 128.4 (3C), 127.9 (3C), 127.8 (3C), 127.5 (3C), 78.4, 74.7, 73.3,
72.7 (2C), 71.5, 67.4, 59.7, 51.5, 44.9, 36.8, 28.8, 23.0; ESI-MS (m/z):
503.5[M þ H]þ.
d:
7.28e7.42 (m, 15H), 7.10 (d, J ¼ 7.8 Hz, 2H), 6.98 (d, J ¼ 7.9 Hz, 2H),
4.44e4.71 (m, 6H), 3.91 (m, 1H), 3.67e3.77 (m, 3H), 3.03 (d,
J ¼ 9.0 Hz,1H), 2.69e2.92 (m, 6H), 2.36 (s, 3H), 2.02 (m,1H),1.71 (m,
5.2.9.20. Synthesis of (2S,3R,4R)-1-(30-ethoxypropyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5l-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:4, V:V)
to afford 5l-3S as slight yellow oil (201.2 mg, 83%). 1H NMR
1H); 13C NMR (75 MHz, CDCl3)
d: 139.0, 138.5, 138.1, 137.6, 135.3,
129.0 (2C), 128.7 (3C), 128.2 (3C), 127.7 (3C), 127.5 (2C), 127.4 (2C),
127.1 (2C), 127.0 (2C), 76.9, 73.5, 71.5, 71.4, 70.7, 65.4, 58.9, 55.4,
(300 MHz, CDCl3) d: 7.42e7.17 (m, 15H, Ph-H), 4.70e4.36 (m, 6H,
46.2, 30.6, 27.4, 21.0; ESI-MS (m/z): 536.5[M
þ
H]þ, 558.4
PhCH2e), 3.75 (m, 1H), 3.63 (m, 2H), 3.51 (m, 1H), 3.40 (m, 4H), 3.24
(dd, J ¼ 9.5, 4.1 Hz, 1H), 2.63 (m, 4H), 1.96 (m, 1H), 1.76 (m, 2H), 1.63
[M þ Na]þ.
(m, 1H), 1.17 (t, J ¼ 7.0 Hz, 3H, CH3e); 13C NMR (75 MHz, CDCl3)
d:
5.2.9.15. Synthesis of (2S,3R,4R)-1-(3-morpholin-N-yl-propyl)-3,4-
bis(benzyloxy)-2- (benzyloxymethyl) piperidine (5i-3S).
139.0,138.7,138.6,128.3 (3C),128.0 (3C),127.6 (3C),127.5 (3C),127.4
(3C), 78.8, 74.9, 73.2, 72.7, 71.4, 69.0, 67.3, 66.1, 59.6, 51.2, 45.7, 28.0,
26.6, 15.3; ESI-MS (m/z): 504.5[M þ H]þ.
Purified by silica gel column chromatography (EtOAc/Petroleum
ether, 1:2, V:V) to afford 5i-3S as slight yellow oil (228.5 mg, 84%).
1H NMR (300 MHz, CDCl3)
d: 7.42e7.26 (m, 15H, Ph-H), 4.73e4.40
5.2.9.21. Synthesis of (2S,3R,4R)-1-propyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5m-3S). Purified by silica gel column
chromatography (EtOAc/Petroleum ether, 1:3, V:V) to afford 5m-3S
(m, 6H, PhCH2-), 3.82e3.50 (m, 8H), 3.24 (m, 1H), 2.63 (m, 4H), 2.41
(m, 4H), 2.30 (m, 2H), 1.99 (m, 1H), 1.69 (m, 3H); 13C NMR (75 MHz,
CDCl3)
d: 139.0, 138.7, 138.5, 128.3 (3C), 128.1 (3C), 127.6 (3C), 127.5
as slight yellow oil (211.2 mg, 92%). 1H NMR (300 MHz, CDCl3)
d:
(3C), 127.4 (3C), 78.8, 74.8, 73.2, 72.6, 71.4, 67.3 (2C), 60.3 (2C), 56.9,
7.45e7.18 (m, 15H, Ph-H), 4.64e4.41 (m, 6H, PhCH2e), 3.73 (dd,
J ¼ 9.8, 5.8 Hz, 1H), 3.63 (m, 2H), 3.50 (m, 1H), 3.22 (dd, J ¼ 9.5,
4.2 Hz, 1H), 2.68e2.48 (m, 4H), 1.97 (m, 1H), 1.65 (m, 1H), 1.46 (m,
52.5 (2C), 46.2, 45.9, 28.1 (2C); ESI-MS (m/z): 545.4[M þ H]þ.
5.2.9.16. Synthesis of (2S,3S,4R)-1-(3-morpholin-N-yl-propyl)-3,4-
2H), 0.83 (t, J ¼ 7.3 Hz, 3H); 13C NMR (75 MHz, CDCl3)
d: 139.1, 138.8,
bis(benzyloxy)-2-
Purified by RP-HPLC (methanol:H2O ¼ 17:3, V:V) to give 5i-3R as
slight yellow oil (223.1 mg, 82%). 1H NMR (300 MHz, CDCl3)
: 7.21e
(benzyloxymethyl)
piperidine
(5i-3R).
138.6, 128.3 (3C), 128.1 (3C), 127.6 (3C), 127.5 (3C), 127.4 (3C), 78.8,
75.0, 73.2, 72.7, 71.4, 67.3, 59.7, 56.4, 45.8, 28.2, 19.5, 11.9; ESI-MS
(m/z): 460.3 [M þ H]þ.
d
7.34 (m, 15H), 4.37e4.62 (m, 6H), 3.82 (m, 1H), 3.56e3.73 (m, 7H),
2.89 (d, J ¼ 8.7 Hz, 1H), 2.52e2.79 (m, 4H), 2.37 (m, 4H), 2.22 (m,
5.2.9.22. Synthesis of (2S,3S,4R)-1-propyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5m-3R). Purified by RP-HPLC
(methanol:H2O ¼ 17:3, V:V) to give 5m-3R as slight yellow oil
2H), 1.94 (m, 1H), 1.59e1.70 (m, 3H); 13C NMR (75 MHz, CDCl3)
d:
138.6, 138.2, 137.9, 128.2 (3C), 128.1 (3C), 127.5 (3C), 127.3 (3C), 127.3
(3C), 76.5, 73.1, 71.2, 71.1, 70.4, 66.6 (2C), 65.4, 59.3, 56.8, 53.4 (2C),
50.9, 45.8, 26.9, 21.7; ESI-MS (m/z): 545.5[M þ H]þ, 567.4[M þ Na]þ.
(191.0 mg, 83.2%). 1H NMR (300 MHz, CDCl3)
d: 7.21e7.34 (m, 15H),
4.37e4.62 (m, 6H), 3.81 (dd, J ¼ 4.6, 2.4 Hz, 1H), 3.53e3.82 (m, 3H),
2.86 (dt, J ¼ 8.8, 2.5 Hz, 1H), 2.46e2.67 (m, 4H), 1.92 (m, 1H), 1.40e
5.2.9.17. Synthesis of (2S,3R,4R)-1-(N,N-dimethylaminoethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5j-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether,1:2, V:V)
to afford 5j-3S as slight yellow oil (202.5 mg, 83%). 1H NMR
1.66 (m, 3H), 0.81 (t, J ¼ 7.3 Hz, 3H); 13C NMR (75 MHz, CDCl3)
d:
139.0,138.6,138.2,128.2 (3C),128.1 (3C),127.6 (3C),127.4 (3C),127.3
(3C), 76.8, 73.3, 71.4, 70.6, 65.4, 59.5, 55.2, 46.1, 40.8, 27.2, 18.0, 11.9;
ESI-MS (m/z): 460.4[M þ H]þ, 482.3[M þ Na]þ.
(300 MHz, CDCl3) d: 7.41e7.21 (m, 15H, Ph-H), 4.73e4.38 (m, 6H,
PhCH2e), 3.75 (dd, J ¼ 9.8, 6.1 Hz, 1H), 3.63 (m, 2H), 3.49 (m, 1H),
3.21 (dd, J ¼ 9.8, 4.1 Hz,1H), 2.74 (m, 2H), 2.64 (m, 2H), 2.45 (m, 2H),
2.24 (s, 6H, CH3-), 1.99 (m, 1H), 1.65 (m, 1H); 13C NMR (75 MHz,
5.2.9.23. Synthesis of (2S,3R,4R)-1-isopropyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5n-3S). Purified by silica gel column
chromatography (EtOAc/Petroleum ether, 1:3, V:V) to afford 5n-3S
CDCl3)
d: 139.0, 138.7, 138.5, 128.3 (3C), 128.0 (3C), 127.6, 127.6 (2C),
as slight yellow oil (212.2 mg, 93%). 1H NMR (300 MHz, CDCl3)
d:
127.5 (2C), 127.4 (2C), 78.8, 74.9, 73.2, 72.7, 71.4, 67.3, 60.3, 56.9,
7.44e7.20 (m, 15H, Ph-H), 4.68e4.41 (m, 6H, PhCH2e), 3.74 (dd,
J ¼ 9.8, 5.7 Hz, 1H), 3.61 (m, 2H), 3.47 (m, 1H), 3.34 (dd, J ¼ 9.5,
4.1 Hz,1H), 3.02 (m, 1H), 2.59 (m, 2H), 1.93 (m,1H), 1.60 (m,1H),1.10
(d, J ¼ 6.4 Hz, 3H), 1.00 (d, J ¼ 6.4 Hz, 3H); 13C NMR (75 MHz, CDCl3)
52.5, 46.2, 45.9 (2C), 28.1; ESI-MS (m/z): 489.5[M þ H]þ.
5.2.9.18. Synthesis of (2S,3S,4R)-1-(N,N-dimethylaminoethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5j-3R). Purified by
RP-HPLC (methanol:H2O ¼ 4:1, V:V) to give 5j-3R as slight yellow
d
: 139.2, 138.9, 138.6, 128.4 (3C), 128.3 (3C), 127.6(3C), 127.5 (3C),
127.4 (3C), 79.3, 75.1, 73.1, 72.6, 71.3, 68.1, 58.2, 50.3, 39.5, 28.8, 21.4,
oil (194.4 mg, 79.7%). 1H NMR (300 MHz, CDCl3)
d: 7.23e7.35 (m,
17.6; ESI-MS (m/z): 460.3 [M þ H]þ.
15H), 4.36e4.60 (m, 6H), 3.82 (m, 1H), 3.73 (dd, J ¼ 10.3, 2.7 Hz),
3.62 (m, 2H), 2.88 (ddd, J ¼ 14.9, 9.8, 5.4 Hz, 2H), 2.61e2.74 (m, 3H),
2.43 (m, 2H), 2.17 (s, 6H), 1.93 (ddd, J ¼ 11.7, 7.1, 3.6 Hz, 1H), 1.61 (m,
5.2.9.24. Synthesis of (2S,3S,4R)-1-isopropyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5n-3R). Purified by RP-HPLC
(methanol:H2O ¼ 17:3, V:V) to give 5n-3R as slight yellow oil
1H); 13C NMR (75 MHz, CDCl3)
d: 138.9, 138.5, 138.1, 128.3 (3C),
128.0 (3C), 127.6, 127.6 (2C), 127.5 (2C), 127.4 (2C), 76.7, 73.4, 71.4,
71.4, 70.7, 65.8, 60.0, 55.7, 51.2, 46.6, 45.83 (2C), 27.2; ESI-MS (m/z):
489.4[M þ H]þ, 511.3[M þ Na]þ.
(196.4 mg, 86.1%). 1H NMR (300 MHz, CDCl3)
d: 7.20e7.34 (m, 15H),
4.33e4.58 (m, 6H), 3.84 (s, 1H), 3.78 (dd, J ¼ 10.4, 2.4 Hz, 1H), 3.63
(ddd, J ¼ 13.0, 9.9, 2.6 Hz, 2H), 3.30 (m, 1H), 2.98 (d, J ¼ 9.3 Hz, 1H),

F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
219
2.56 (m, 2H), 1.93 (m, 1H), 1.57 (m, 1H), 1.14 (d, J ¼ 6.7 Hz, 3H), 0.88
5.2.9.30. Synthesis of (2S,3S,4R)-1-hydroethyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5q-3R). Purified by RP-HPLC
(methanol:H2O ¼ 9:1, V:V) to give 5q-3R as slight yellow oil
(d, J ¼ 6.5 Hz, 3H); 13C NMR (75 MHz, CDCl3)
d: 138.9, 138.5, 138.1,
128.3 (3C), 128.2 (3C), 127.5(3C), 127.4 (3C), 127.3 (3C), 77.2, 73.2,
71.3, 71.2, 71.0, 65.2, 58.3, 47.6, 37.3, 27.4, 21.5, 13.6; ESI-MS (m/z):
460.4[M þ H]þ, 482.3[M þ Na]þ.
(178.5 mg, 77.6%). 1H NMR (300 MHz, CDCl3)
d: 7.22e7.34 (m, 15H),
4.28e4.83 (m, 6H), 3.47e3.70 (m, 6H), 2.99 (m, 2H), 2.65 (dd, 12.9,
6.2 Hz, 2H), 2.54 (dt, J ¼ 13.4, 4.0 Hz, 1H), 1.95 (ddd, J ¼ 14.6, 10.3,
4.3 Hz, 1H), 1.57 (m, 1H); 13C NMR (75 MHz, CDCl3)
d: 138.7, 138.4,
5.2.9.25. Synthesis of (2S,3R,4R)-1-butyl-3,4-bis(benzyloxy)-2-(ben-
zyloxymethyl) piperidine (5o-3S). Purified by silica gel column
chromatography (EtOAc/Petroleum ether, 1:3, V:V) to afford 5o-3S
137.8, 127.35e128.29(15C), 76.1, 73.2, 71.9, 71.5, 70.5, 66.3, 60.6,
58.9, 54.5, 45.9, 26.5; ESI-MS (m/z): 462.5[M
þ
H]þ, 484.5
[M þ Na]þ.
as slight yellow oil (200.7 mg, 85%). 1H NMR(300 MHz, CDCl3)
d:
7.44e7.20 (m, 15H, Ph-H), 4.68e4.41 (m, 6H, PhCH2e), 3.75 (dd,
J ¼ 9.9, 5.8 Hz,1H, H-7a), 3.63 (m, 2H), 3.51 (m, 1H), 3.24 (dd, J ¼ 9.6,
4.1 Hz,1H), 2.63 (m, 4H),1.98 (m,1H),1.65 (m,1H),1.45 (m, 2H),1.26
5.2.9.31. Synthesis of (2S,3R,4R)-1-hydropropyl-3,4-bis(benzyloxy)-
2-(benzyloxy -methyl) piperidine (5r-3S). Purified by silica gel col-
umn chromatography (EtOAc/Petroleum ether, 1:1, V:V) to afford
5r-3S as slight yellow oil (166.3 mg, 70%). 1H NMR(300 MHz, CDCl3)
(m, 2H), 0.90 (t, J ¼ 4.3 Hz, 3H, CH3e); 13C NMR (75 MHz, CDCl3)
d:
139.2, 138.9, 138.6, 128.4 (3C), 128.3 (3C), 127.6 (3C), 127.5 (3C),
127.4 (3C), 78.5, 74.6, 73.2, 72.7, 71.4, 67.2, 59.7, 54.2, 45.8, 28.0, 27.9,
20.7, 14.1; ESI-MS (m/z): 474.3[M þ H]þ.
d: 7.50e7.20 (m, 15H, Ph-H), 4.74e4.43 (m, 6H, PhCH2e), 3.80 (m,
3H), 3.67 (m, 2H), 3.60 (m, 1H), 3.28 (m, 1H), 3.00 (m, 1H), 2.81 (m,
1H), 2.72 (m, 2H), 2.02 (m, 1H), 1.79 (m, 1H), 1.69 (m, 2H); 13C NMR
(75 MHz, CDCl3) d: 138.8, 138.6, 138.2, 128.4 (3C), 128.3 (3C), 127.7
5.2.9.26. Synthesis of (2S,3S,4R)-1-butyl-3,4-bis(benzyloxy)-2-(ben-
(3C),127.6 (3C),127.5 (3C), 78.8, 74.4, 73.2, 72.7, 71.5, 67.7, 64.4, 60.9,
54.3, 45.5, 27.8, 27.4; ESI-MS(m/z): 476.3 [M þ H]þ.
zyloxymethyl)
(methanol:H2O ¼ 17:3, V:V) to give 5o-3R as slight yellow oil
(211.1 mg, 89.4%). 1H NMR (300 MHz, CDCl3)
: 7.21e7.34 (m, 15H),
piperidine
(5o-3R). Purified
by
RP-HPLC
d
5.2.9.32. Synthesis of (2S,3S,4R)-1-hydropropyl-3,4-bis(benzyloxy)-
2-(benzyloxy-methyl) piperidine (5r-3R). Purified by RP-HPLC
(methanol:H2O ¼ 9:1, V:V) to give 5r-3R as slight yellow oil
4.36e4.62 (m, 6H), 3.81 (m, 1H), 3.54e3.69 (m, 3H), 2.86 (d,
J ¼ 8.9 Hz,1H), 2.47e2.74 (m, 4H),1.92 (m,1H),1.63 (m,1H),1.42 (m,
2H), 1.22 (m, 2H), 0.87 (t, J ¼ 7.3 Hz, 3H); 13C NMR (75 MHz, CDCl3)
(200.3 mg, 84.3%). 1H NMR (300 MHz, CDCl3)
d: 7.22e7.34 (m, 15H),
d: 139.0, 138.6, 138.2, 1128.4 (3C), 128.3 (3C), 127.6 (3C), 127.5 (3C),
4.42e4.78 (m, 6H), 3.71e3.77 (m, 4H), 3.63 (m, 2H), 3.07 (m, 1H),
2.96 (m, 1H), 2.78 (m, 1H), 2.58 (m, 2H), 1.99 (ddd, J ¼ 11.6, 9.1,
5.8 Hz, 1H), 1.82 (ddd, J ¼ 15.9, 10.1, 4.6 Hz, 1H), 1.59 (m, 2H); 13C
127.4 (3C), 76.8, 73.3, 71.4, 71.4, 70.6, 65.4, 59.5, 53.0, 46.1, 27.3, 27.0,
20.8, 14.1; ESI-MS (m/z): 474.5[M þ H]þ, 496.3 [M þ Na]þ.
NMR (75 MHz, CDCl3) d: 138.9, 138.5, 138.1, 127.57e128.72(15C),
76.3, 73.4, 71.9, 71.7, 70.8, 66.3, 63.4, 61.4, 52.8, 45.6, 27.8, 26.7; ESI-
5.2.9.27. Synthesis of (2S,3R,4R)-1-isobutyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5p-3S). Purified by silica gel column
chromatography (EtOAc/Petroleum ether, 1:3, V:V) to afford 5p-3S
MS (m/z): 476.7[M þ H]þ, 498.6[M þ Na]þ.
as slight yellow oil (200.2 mg, 85%). 1H NMR (300 MHz, CDCl3)
d:
5.2.9.33. Synthesis of (2S,3R,4R)-1-(2-(thiophen-2-yl)ethyl)-3,4-
bis(benzyloxy)-2-(benzyloxymethyl) piperidine (5s-3S). Purified by
silica gel column chromatography (EtOAc/Petroleum ether, 1:1, V:V)
to afford 5s-3S as slight yellow oil (237.2 mg, 90.2%). 1H NMR
7.43e7.16 (m, 15H, Ph-H), 4.75e4.39 (m, 6H, PhCH2e), 3.75 (dd,
J ¼ 9.9, 5.8 Hz, 1H), 3.67 (m, 2H), 3.50 (m, 1H), 3.31 (m, 1H), 2.59 (m,
2H), 2.38 (d, J ¼ 6.6 Hz, 2H), 1.94 (m, 1H), 1.70 (m, 1H), 1.54 (m, 1H),
0.86 (d, J ¼ 6.5 Hz, 6H); 13C NMR (75 MHz, CDCl3)
d
: 139.2, 138.9,
(300 MHz, CDCl3)
d
: 7.40e7.26 (m, 15H, Ph-H), 7.14 (dd, J ¼ 5.1,
1.2 Hz, 1H), 6.93 (dd, J ¼ 5.1, 3.3 Hz, 1H), 6.77 (d, J ¼ 3.3 Hz, 1H),
4.73e4.43 (m, 6H, PhCH2e), 3.87e3.50 (m, 4H), 3.42e3.32 (m, 1H),
3.08e2.95 (m, 4H), 2.77e2.68 (m, 2H), 2.10e1.95 (m, 1H), 1.79e1.67
138.7, 128.3 (3C), 127.8 (3C), 127.7 (3C), 127.5 (3C), 127.4 (3C), 79.6,
73.2, 72.6, 71.8, 65.9, 62.7, 62.6, 60.8, 45.7, 29.5, 26.4, 20.9 (2C); ESI-
MS (m/z): 474.3[M þ H]þ.
(m, 1H); 13C NMR (75 MHz, CDCl3)
d: 143.3, 139.0, 138.7, 137.5, 128.3
(3C), 128.1 (3C), 127.7 (3C), 127.5 (3C), 126.5 (3C), 126.4, 126.2, 123.6,
79.0, 75.0, 73.3, 72.6, 71.5, 67.4, 54.6, 46.8, 30.7, 28.3, 27.0; ESI-MS
(m/z): 528.3[M þ H]þ.
5.2.9.28. Synthesis of (2S,3S,4R)-1-isobutyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5p-3R). Purified by RP-HPLC
(methanol:H2O ¼ 17:3, V:V) to give 5o-3R as slight yellow oil
(199.0 mg, 84.5%). 1H NMR (300 MHz, CDCl3)
d: 7.23e7.35 (m, 15H),
5.2.10. General procedure for the syntheses of 6a-s-3S and 6a-r-3R
Any of the compounds 5a-s-3S and 5a-r-3R (0.1e0.3 g, identified
in specific reaction) was dissolved in 10% TFA in MeOH (10 ml)
following the addition of 10% Pd/C (300 mg). The reaction mixture
was subjected to 5 atm H2 for 48 h with stirring at room temper-
ature. The catalyst was filtered off through Celite and the filtrate
was concentrated in vacuo followed purification by RP-HPLC.
4.40e4.61 (m, 6H), 3.76 (dd, J ¼ 5.9, 2.8 Hz, 1H), 3.66 (m, 2H), 3.56
(dd, J ¼ 10.1, 3.9 Hz, 1H), 2.91 (dt, J ¼ 7.2, 3.5 Hz, 1H), 2.43e2.67 (m,
3H), 2.18 (dd, J ¼ 12.7, 5.5 Hz, 1H), 1.96 (m, 1H), 1.75 (m, 1H), 1.58 (m,
1H), 0.87 (dd, J ¼ 12.1, 6.6 Hz, 6H); 13C NMR (75 MHz, CDCl3)
d:
139.0,138.8,138.3,128.4 (3C),127.8 (3C),127.7 (3C),127.4 (3C),127.3
(3C), 76.4, 73.2, 72.1, 71.4, 70.4, 66.8, 62.1, 61.1, 46.7, 26.7, 26.4, 21.4,
20.9; ESI-MS (m/z): 474.5[M þ H]þ, 496.3 [M þ Na]þ.
5.2.10.1. Synthesis of (2S,3R,4R)-2-(hydroxymethyl)piperidine-3,4-
5.2.9.29. Synthesis of (2S,3R,4R)-1-hydroethyl-3,4-bis(benzyloxy)-2-
(benzyloxymethyl) piperidine (5q-3S). Purified by silica gel column
chromatography (EtOAc/Petroleum ether, 1:1, V:V) to afford 5q-3S
diol (6a-3S). 5a-3S (218.7 mg, 0.44 mmol). Purified by RP-HPLC
(methanol:H2O
(38.8 mg, 60%). 1H NMR (300 MHz, D2O)
1H), 3.71 (m, 2H), 3.42 (dd, J ¼ 8.2, 1.5 Hz, 1H, H-3), 3.0 (m, 1H, H-2),
¼
1:9, V:V) to give 6a-3S as white crystal
d: 3.83 (dd, J ¼ 3.2, 12.6 Hz,
as slight yellow oil (165.6 mg, 72%). 1H NMR (300 MHz, CDCl3)
d:
7.38e7.14 (m, 15H, Ph-H), 4.64e4.35 (m, 6H, PhCH2e), 3.80 (dd,
J ¼ 10.3, 6.9 Hz, 1H), 3.74e3.53 (m, 5H), 3.47 (m, 1H), 3.15e2.84 (m,
2.82 (m, 2H), 2.09 (m, 1H), 1.72 (m, 1H); 13C NMR (75 MHz, D2O)
d:
65.7, 64.8, 59.5, 55.7, 38.8, 23.6; HRMS (m/z): calcd for C6H14NOþ3 H:
4H), 2.08 (m, 1H), 1.70 (m, 1H); 13C NMR (75 MHz, CDCl3)
d: 138.3,
148.09737, found: 148.09741.
137.8, 137.7, 128.5 (3C), 128.5 (3C), 127.9 (3C), 127.8 (3C), 127.6 (3C),
77.4, 77.0, 73.3, 72.8, 71.6, 66.9, 60.4, 57.8, 54.9, 46.0, 25.3; ESI-MS
(m/z): 462.5[M þ H]þ.
5.2.10.2. Synthesis of (2S,3S,4R)-2-(hydroxymethyl)piperidine-3,4-
diol (6a-3R). 5a-3R (215.3 mg, 0.43 mmol). Purified by RP-HPLC

220
F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
(methanol:H2O ¼ 1:9, V:V) to give 6a-3R as white crystal (58.0 mg,
91.1%). 1H NMR (300 MHz, CD3OD)
: 3.75e4.10 (m, 4H), 3.14e3.33
ESI-MS (m/z): 270.3 [M þ H]þ, 292.3[M þ Na]þ; HRMS (m/z): calc
d
for C14H20FNOþ3 H: 270.15055, found: 270.15022.
(m, 3H), 1.95e2.06 (m, 2H); 13C NMR (75 MHz, CD3OD)
d: 66.5, 65.6,
58.1, 56.1, 38.1, 27.7; ESI-MS (m/z): 148.2[M þ H]þ; HRMS (m/z): calc
5.2.10.9. Synthesis of (2S,3R,4R)-1-(3-fluorophenethyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6e-3S). 5e-3S (212.9 mg, 0.39 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 3:7, V:V) to give 6e-3S as
for C6H13NOþ3 H: 148.09737, found: 148.09743.
white solid (53.9 mg, 52%). 1H NMR (300 MHz, CD3OD)
d: 7.23 (m,
5.2.10.3. Synthesis of (2S,3R,4R)-1-phenethyl-2-(hydroxymethyl)
piperidine-3,4-diol (6b-3S). 5b-3S (234.5 mg, 0.45 mmol). Purified
by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give 6b-3S as white solid
2H, AreH), 6.97 (m, 2H, AreH), 3.83 (m, 2H), 3.70e3.60 (m, 2H),
3.01 (dd, J ¼ 8.6, 5.3 Hz, 1H), 2.95e2.67 (m, 6H), 1.96 (m, 1H), 1.57
(103.9 mg, 92%). 1H NMR (300 MHz, CD3OD)
d: 7.3e7.1 (m, 5H, Are
(m, 1H); 13C NMR (75 MHz, CD3OD)
d: 162.8, 139.9, 130.9, 123.9,
H), 3.83 (m, 2H), 3.70e3.60 (m, 2H), 2.99 (m, 1H), 2.98e2.60 (m,
114.6, 112.7, 72.1, 68.4, 61.5, 58.6, 54.1, 45.1, 31.4, 29.0; HRMS (ESI):
6H), 1.95 (m, 1H), 1.58 (m, 1H); 13C NMR (75 MHz, CD3OD)
d: 140.4,
calcd. for C14H20FNOþ3 H: 270.15055, found: 270.15027.
128.4 (2C), 128.0 (2C), 125.6, 72.2, 68.4, 61.6, 58.6, 55.8, 45.2, 32.2,
29.0; HRMS (m/z): calcd for C14H21NOþ3 H: 252.15997, found:
252.15995.
5.2.10.10. Synthesis of (2S,3S,4R)-1-(3-fluorophenethyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6e-3R). 5e-3R (262.9 mg, 0.49 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 9:11, V:V) to give 6e-3R as
5.2.10.4. Synthesis of (2S,3S,4R)-1-phenethyl-2-(hydroxymethyl)
piperidine-3,4-diol (6b-3R). 5b-3R (219.6 mg, 0.42 mmol). Purified
by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give 6b-3R as white solid
white solid (123.7 mg, 94.3%). 1H NMR (300 MHz, CD3OD)
d: 7.22
(m, 2H, AreH), 7.04 (m, 2H, AreH), 3.65e3.87 (m, 4H), 2.67e3.01
(m, 7H), 1.95 (m, 1H), 1.57 (m, 1H); 13C NMR (75 MHz, CD3OD)
d:
(103.7 mg, 98%). 1H NMR (300 MHz, CD3OD)
d: 7.23e7.37 (m, 5H,
161.8, 133.1, 129.9 (2C), 117.7, 117.0, 74.4, 70.7, 63.8, 60.9, 56.3, 47.3,
31.2, 27.7; ESI-MS (m/z): 270.3 [M þ H]þ, 292.2[M þ Na]þ; HRMS
(m/z): calc for C14H20FNOþ3 H: 270.15055, found: 270.15022.
AreH), 3.84e4.15 (m, 4H), 2.98e3.54 (m, 7H), 1.94e2.03 (m, 2H);
13C NMR (75 MHz, CD3OD)
d: 138.6, 128.8 (2C), 128.6 (2C), 126.1,
68.4, 67.2, 64.3, 56.0, 48.6, 48.7, 31.3, 29.7; ESI-MS (m/z): 252.4
[M þ H]þ, 274.3[M þ Na]þ; HRMS (m/z): calc for C14H21NOþ3 H:
252.15997, found: 252.15989.
5.2.10.11. Synthesis of (2S,3R,4R)-1-(2-(1H-imidazol-4-yl)ethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6f-3S). 5f-3S (178.9 mg,
0.35 mmol). Purified by RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give
5.2.10.5. Synthesis
of
(2S,3R,4R)-1-(4-methoxyphenethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6c-3S). 5c-3S (246.0 mg,
0.45 mmol). Purified by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give
6f-3S as colorless oil (39.6 mg, 47%). 1H NMR (300 MHz, CD3OD)
d:
7.44 (d, J ¼ 8.3 Hz, 1H), 6.73 (d, J ¼ 9.1 Hz, 1H), 3.79e3.60 (m, 4H),
6c-3S as white solid (102.5 mg, 82%). 1H NMR (300 MHz, CD3OD)
d:
3.27 (m, 1H), 2.93e2.50 (m, 6H), 1.95 (m, 1H), 1.76 (m, 1H); 13C NMR
7.11 (d, J ¼ 8.6 Hz, 2H, AreH), 6.82 (d, J ¼ 9.1 Hz, 2H, AreH), 3.83 (m,
2H), 3.74 (s, 3H, eOCH3), 3.70e3.60 (m, 2H), 2.99 (m, 1H), 2.98e
2.60 (m, 6H), 1.95 (m, 1H), 1.58 (m, 1H); 13C NMR (75 MHz, CD3OD)
(75 MHz, CD3OD) d: 134.3, 131.4, 122.6, 73.5, 73.1, 71.4, 60.3, 52.3,
44.5, 29.0, 26.8; HRMS (m/z): calcd for C11H19N3Oþ3 H: 242.14992,
found: 242.14969.
d
: 158.2, 132.4, 129.3 (2C), 113.6 (2C), 72.2, 68.4, 61.6, 58.6, 55.9,
54.9, 45.2, 31.3, 29.0; HRMS (m/z): calcd. for
C
15H23NOþ4 H:
5.2.10.12. Synthesis of (2S,3R,4R)-1-(4-sulphonamidophenethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6g-3S). 5g-3S (195.0 mg,
0.32 mmol). Purified by RP-HPLC (methanol:H2O ¼ 1:4, V:V) to give
282.17053, found: 282.16983.
6g-3S as colorless oil (69.7 mg, 60%). 1H NMR (300 MHz, D2O)
d:
5.2.10.6. Synthesis
of
(2S,3S,4R)-1-(4-methoxyphenethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6c-3R). 5c-3R (270.9 mg,
0.49 mmol). Purified by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give
6c-3R as white solid (131.5 mg, 95.2%). 1H NMR (300 MHz, CD3OD)
7.66 (d, J ¼ 8.4 Hz, 2H, AreH), 7.27 (d, J ¼ 8.4 Hz, 2H, AreH), 3.70 (m,
2H), 3.58 (m, 2H), 2.97 (m, 1H), 2.88e2.34 (m, 6H), 1.81 (m, 1H), 1.45
(m, 1H); 13C NMR (75 MHz, D2O)
d: 145.5, 139.8, 129.5 (2C), 125.8
d
: 7.11 (d, J ¼ 8.6 Hz, 2H), 6.88 (d, J ¼ 9.1 Hz, 2H), 3.93 (m, 1H), 3.91
(dd, J ¼ 7.4, 3.1 Hz, 2H), 3.74 (s, 3H), 3.61 (dd, J ¼ 8.6, 3.0 Hz, 1H),
2.65e2.97 (m, 7H), 1.70e1.86 (m, 2H); 13C NMR (75 MHz, CD3OD)
(2C), 71.7, 68.3, 61.6, 57.1, 54.6, 44.8, 31.7, 28.8; HRMS (m/z): calcd
for C14H22N2Oþ5 H: 331.13222, found: 331.13177.
d:
158.1, 132.1, 129.3 (2C), 113.6 (2C), 68.9, 67.1, 61.7, 58.0, 55.3, 54.3,
45.1, 29.9, 29.1; ESI-MS (m/z): 282.3[M þ H]þ, 304.2[M þ Na]þ;
HRMS (m/z): calc for C15H23NO4þH: 282.17053, found: 282.16981.
5.2.10.13. Synthesis of (2S,3R,4R)-1-(4-methylphenethyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6h-3S). 5h-3S (246.6 mg, 0.46 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give 6h-3S as
white solid (87.8 mg, 72%). 1H NMR (300 MHz, CD3OD)
d: 7.10 (m,
5.2.10.7. Synthesis of (2S,3R,4R)-1-(4-fluorophenethyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6d-3S). 5d-3S (218.3 mg, 0.40 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 3:7, V:V) to give 6d-3S as
4H, AreH), 3.86 (m, 2H), 3.71 (m, 2H), 3.10 (m, 1H), 2.98 (m, 2H),
2.82 (m, 2H), 2.28 (s, 3H), 2.03 (m, 1H), 1.63 (m, 1H); 13C NMR
white solid (77.4 mg, 71%). 1H NMR (300 MHz, CD3OD)
d: 7.23 (m,
(75 MHz, CD3OD)
61.5, 58.8, 55.5, 45.3, 31.2, 28.3, 19.7; HRMS (m/z): calcd for
15H23NOþ3 H: 266.17507, found: 266.17511.
d: 136.6, 135.3, 128.7 (2C), 128.3 (2C), 71.8, 67.9,
2H, AreH), 7.03 (m, 2H, AreH), 3.83 (m, 2H), 3.70e3.60 (m, 2H),
3.01 (dd, J ¼ 8.4, 5.1 Hz), 2.97e2.68 (m, 6H), 1.98 (m, 1H), 1.60 (m,
C
1H); 13C NMR (75 MHz, CD3OD)
d: 162.6, 136.1, 129.9 (2C), 114.7
(2C), 72.2, 68.5, 61.7, 58.8, 55.5, 45.2, 31.3, 29.0; HRMS (m/z): calcd.
5.2.10.14. Synthesis of (2S,3S,4R)-1-(4-methylphenethyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6h-3R). 5h-3R (240.2 mg, 0.45 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give 6h-3R as
for C14H20FNOþ3 H: 270.15055, found: 270.15027.
5.2.10.8. Synthesis of (2S,3S,4R)-1-(4-fluorophenethyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6d-3R). 5d-3R (246.9 mg, 0.46 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 9:11, V:V) to give 6d-3R as
white solid (111.0 mg, 93.3%). 1H NMR (300 MHz, CD3OD)
d: 7.10 (s,
4H, AreH), 3.94 (m, 1H), 3.89 (d, J ¼ 4.0 Hz, 2H), 3.65 (m, 1H), 2.83e
3.07 (m, 7H), 2.29 (s, 3H, CH3), 1.82 (m, 2H); 13C NMR (75 MHz,
white solid (120.2 mg, 97.6%). 1H NMR (300 MHz, CD3OD)
d: 7.32
CD3OD) d: 138.6, 136.5, 130.1 (2C), 129.6 (2C), 70.3, 68.5, 63.1, 59.5,
(m, 2H, AreH), 7.06 (m, 2H, AreH), 3.84e4.12 (m, 4H), 3.07e3.45
(m, 7H), 2.01 (m, 2H); 13C NMR (75 MHz, CD3OD)
: 162.6, 134.8,
132.6 (2C), 117.4 (2C), 68.7, 67.3, 64.6, 56.6, 55.8, 48.3, 30.8, 29.5;
56.6, 46.4, 30.6, 30.1, 21.1; ESI-MS (m/z): 266.3[M þ H]þ, 288.2
[M þ Na]þ; HRMS (m/z): calc for C15H23NOþ3 H: 266.17507, found:
266.17507 [M þ H]þ.
d

F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
221
5.2.10.15. Synthesis of (2S,3R,4R)-1-(3-morpholin-N-yl-propyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6i-3S). 5i-3S (228.5 mg,
0.42 mmol). Purified by RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give
d: 71.9, 62.3, 61.7, 56.7, 55.2, 45.0, 28.9, 18.7, 11.1; HRMS (m/z):
C9H19NOþ3 H: 190.14432, found 190.14356.
6i-3S as colorless oil (73.7 mg, 64%). 1H NMR (300 MHz, D2O)
d: 3.73
5.2.10.22. Synthesis of (2S,3S,4R)-1-propyl-2-(hydroxymethyl)piper-
idine-3,4-diol (6m-3R). 5m-3R (191.0 mg, 0.42 mmol). Purified by
RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give 6m-3R as white solid
(m, 2H), 3.58 (m, 6H), 2.91 (m, 1H), 2.62e2.33 (m, 8H), 2.26 (t,
J ¼ 7.8 Hz, 2H), 1.82 (m, 1H), 1.62 (m, 2H), 1.45 (m, 1H); 13C NMR
(75 MHz, D2O)
51.3, 44.9, 29.0, 22.0; HRMS (m/z): calcd for
d
: 71.9, 68.4, 66.1 (2C), 61.8, 56.8, 56.0, 52.4 (2C),
(63.9 mg, 81.2%). 1H NMR (300 MHz, CD3OD)
d: 3.90 (m, 1H), 3.82
C
13H26N2Oþ4 H:
(d, J ¼ 3.6 Hz, 2H), 3.60 (dd, J ¼ 8.7, 3.1 Hz, 1H), 2.53e2.71 (m, 5H),
275.19708, found: 275.19712.
1.73 (m, 2H), 1.54 (m, 2H), 0.90 (t, J ¼ 7.4 Hz, 3H, CH3); 13C NMR
(75 MHz, CD3OD) d: 70.4, 68.5, 63.4, 59.5, 56.5, 46.4, 30.6, 19.1, 12.2;
5.2.10.16. Synthesis of (2S,3S,4R)-1-(3-morpholin-N-yl-propyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6i-3R). 5i-3R (223.1 mg,
0.42 mmol). Purified by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give
6i-3R as colorless oil (92.8 mg, 82.6%). 1H NMR (300 MHz, CD3OD)
ESI-MS (m/z): 190.3[M þ H]þ, 212.3[M þ Na]þ; HRMS (m/z): calc for
C9H19NOþ3 H: 190.14432, found: 190.14377.
5.2.10.23. Synthesis of (2S,3R,4R)-1-isopropyl-2-(hydroxymethyl)
piperidine-3,4-diol (6n-3S). 5n-3S (212.2 mg, 0.46 mmol). Purified
by RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give 6n-3S as white solid
d
: 3.95 (d, J ¼ 4.2 Hz, 1H), 3.89 (d, J ¼ 2.6 Hz, 2H), 3.72 (m, 4H), 3.63
(dd, J ¼ 8.9, 3.0 Hz, 1H), 2.96 (m, 1H), 2.36e2.73 (m, 10H), 1.26e1.42
(m, 4H); 13C NMR (75 MHz, CD3OD)
: 69.9, 68.4, 67.4 (2C), 63.7,
d
(61.2 mg, 70%). 1H NMR (300 MHz, D2O)
d: 3.74 (m, 2H), 3.67e3.52
58.8, 57.9, 54.7 (2C), 51.5, 46.3, 30.6, 22.6; ESI-MS (m/z): 275.3
[M þ H]þ, 297.3[M þ Na]þ; HRMS (m/z): calc for C13H26N2Oþ4 H:
275.19708, found: 275.19703.
(m, 2H), 2.96 (dd, J ¼ 9.7, 5.1 Hz, 1H), 2.67 (m, 1H), 2.47 (m, 1H), 1.83
(m, 1H), 1.43 (m, 1H), 1.00 (d, J ¼ 6.4 Hz, 3H), 0.95 (d, J ¼ 6.4 Hz, 3H);
13C NMR (75 MHz, D2O)
d: 72.1, 68.3, 59.3, 57.6, 49.2, 39.8, 28.9, 20.1,
16.8; HRMS (m/z): calc for C9H19NOþ3 H: 190.14432, found:
5.2.10.17. Synthesis of (2S,3R,4R)-1-(N,N-dimethylaminoethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6j-3S). 5j-3S (202.5 mg,
0.41 mmol). Purified by RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give
190.14356.
5.2.10.24. Synthesis of (2S,3S,4R)-1-isopropyl-2-(hydroxymethyl)
piperidine-3,4-diol (6n-3R). 5n-3R (196.4 mg, 0.43 mmol). Purified
by RP-HPLC (methanol:H2O ¼ 2:3, V:V) to give 6n-3R as white solid
6j-3S as white solid (40.7 mg, 45%). 1H NMR (300 MHz, D2O)
d: 3.69
(m, 2H), 3.60e3.45 (m, 2H), 2.86 (dd, J ¼ 9.5, 4.3 Hz, 1H), 2.78e2.36
(m, 6H), 2.14 (s, 6H), 1.78 (m, 1H), 1.41 (m, 1H); 13C NMR (75 MHz,
(68.4 mg, 84.6%). 1H NMR (300 MHz, CD3OD)
d: 3.92 (dt, J ¼ 9.0,
D2O)
d
: 71.7, 68.4, 62.8, 56.9, 55.1, 50.2, 44.9, 44.0 (2C), 28.9; HRMS
4.5 Hz,1H), 3.86 (d, J ¼ 3.3 Hz, 2H), 3.60 (dd, J ¼ 9.0, 3.1 Hz,1H), 3.38
(dt, J ¼ 13.1, 6.6 Hz, 1H), 2.69 (dt, J ¼ 8.9, 3.3 Hz, 1H), 1.73 (m, 2H),
2.59 (m, 2H), 1.14 (d, J ¼ 6.7 Hz, 3H, CH3), 0.98 (d, J ¼ 6.5 Hz, 3H,
(m/z): calcd for C10H22N2Oþ3 H: 219.17087, found: 219.17081.
5.2.10.18. Synthesis of (2S,3S,4R)-1-(N,N-dimethylaminoethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6j-3R). 5j-3R (194.4 mg,
0.40 mmol). Purified by RP-HPLC (methanol:H2O ¼ 3:7, V:V) to give
CH3); 13C NMR (75 MHz, CD3OD)
d: 70.5, 68.7, 61.7, 59.2, 49.2, 38.0,
31.0, 21.6, 14.2; ESI-MS (m/z): 190.4 [M þ H]þ, 212.4[M þ Na]þ;
HRMS (m/z): calc for C9H19NO3þH: 190.14432, found: 190.14377.
6j-3R as white solid (75.8 mg, 87.3%). 1H NMR (300 MHz, CD3OD)
d:
3.79e3.88 (m, 3H), 3.61 (dd, J ¼ 7.8, 3.0 Hz, 1H), 2.92 (dt, J ¼ 13.5,
5.2.10.25. Synthesis of (2S,3R,4R)-1-butyl-2-(hydroxymethyl)piperi-
dine-3,4-diol (6o-3S). 5o-3S (200.7 mg, 0.42 mmol). Purified by RP-
HPLC (methanol:H2O ¼ 1:9, V:V) to give 6o-3S as white solid
6.7 Hz,1H), 2.49e2.75 (m, 6H), 2.31 (s, 6H, 2CH3),1.19e1.31 (m, 2H);
13C NMR (75 MHz, CD3OD)
d: 70.2, 68.5, 64.7, 59.2, 57.6, 51.6, 46.5,
45.6 (2C), 30.3; ESI-MS (m/z): 219.1[M þ H]þ, 241.2[M þ Na]þ;
(40.5 mg, 47%). 1H NMR (300 MHz, D2O)
d: 3.70 (m, 2H), 3.70e3.50
HRMS (m/z): calcd for C10H22N2Oþ3 H: 219.17087, found: 219.17104.
(m, 2H), 2.91 (dd, J ¼ 9.7, 5.1 Hz, 1H), 2.68e2.38 (m, 4H), 1.80 (m,
1H),1.53e1.57 (m, 3H),1.16 (m, 2H), 0.77 (t, J ¼ 7.2 Hz, 3H); 13C NMR
5.2.10.19. Synthesis
of
(2S,3R,4R)-1-(20-acetlyaminoethyl)-2-
(75 MHz,D2O) d: 72.0, 68.4, 61.8, 56.8, 53.2, 45.0, 29.9, 27.6, 20.2,
(hydroxymethyl) piperidine-3,4-diol (6k-3S). 5k-3S (208.3 mg,
0.41 mmol). Purified by RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give
13.3; HRMS (m/z): calc for C
10H21NOþ3 H: 204.15997, found:
204.15942.
6k-3S as white solid (59.7 mg, 62%). 1H NMR (300 MHz, CD3OD)
d:
3.81 (m, 2H), 3.70e3.60 (m, 2H), 3.30 (m, 2H), 3.02e2.60 (m, 5H),
5.2.10.26. Synthesis of (2S,3S,4R)-1-butyl-2-(hydroxymethyl)piperi-
dine-3,4-diol (6o-3R). 5o-3R (211.1 mg, 0.45 mmol). Purified by RP-
HPLC (methanol:H2O ¼ 3:2, V:V) to give 6o-3R as white solid
1.96 (s, 3H), 1.91 (m, 1H), 1.57 (m, 1H); 13C NMR (75 MHz, CD3OD)
d:
170.9, 71.9, 68.6, 62.8, 58.8, 52.3, 44.9, 36.9, 28.9, 21.2; HRMS (m/z):
calcd for C10H20N2Oþ4 H: 233.15013, found: 233.14981.
(69.6 mg, 76.8%). 1H NMR (300 MHz, D2O)
d: 3.61e3.78 (m, 4H),
2.93 (m, 1H), 2.52 (m, 4H), 1.82 (m, 1H), 1.33e1.45 (m, 3H), 1.18 (dd,
5.2.10.20. Synthesis of (2S,3R,4R)-1-(30-ethoxypropyl)-2-(hydrox-
ymethyl) piperidine-3,4-diol (6l-3S). 5l-3S (201.2 mg, 0.40 mmol).
Purified by RP-HPLC (methanol:H2O ¼ 3:7, V:V) to give 6l-3S as
J ¼ 14.2, 7.0 Hz, 2H), 0.79 (t, J ¼ 7.2 Hz, 3H); 13C NMR (75 MHz, D2O)
d
: 72.0, 68.4, 61.8, 56.8, 53.2, 45.0, 27.6, 29.0, 20.2, 13.3; ESI-MS (m/
z): 204.2[M þ H]þ, 226.1[M þ Na]þ; HRMS (m/z): calc for
colorless oil (62.4 mg, 67%). 1H NMR (300 MHz, D2O)
d: 3.74 (m, 2H),
C
10H21NOþ3 H: 204.15997, found: 204.15998.
3.61 (m, 2H), 3.53e3.36 (m, 4H), 2.91 (m, 1H), 2.56 (m, 4H), 1.84 (m,
1H), 1.68 (m, 2H), 1.47 (m, 1H), 1.08 (t, J ¼ 7.1 Hz, 3H); 13C NMR
5.2.10.27. Synthesis of (2S,3R,4R)-1-isobutyl-2-(hydroxymethyl)
piperidine-3,4-diol (6p-3S). 5p-3S (200.2 mg, 0.42 mmol). Purified
by RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give 6p-3S as white solid
(75 MHz, D2O) d: 71.8, 68.6, 68.3, 66.2, 61.9, 56.9, 50.2, 44.9, 28.8,
25.5, 14.1; HRMS (m/z): calcd for C11H23NOþ4 H: 234.17053, found:
234.16992.
(44.8 mg, 52%). 1H NMR (300 MHz, D2O)
d: 3.70 (m, 2H),3.58 (m,
2H), 2.92 (m, 1H, H-2), 2.66e2.40 (m, 2H), 2.32 (m, 2H), 1.72 (m,
5.2.10.21. Synthesis of (2S,3R,4R)-1-propyl-2-(hydroxymethyl)piper-
idine-3,4-diol (6m-3S). 5m-3S (211.2 mg, 0.46 mmol). Purified by
RP-HPLC (methanol:H2O ¼ 1:9, V:V) to give 6m-3S as white solid
2H), 1.48 (m, 1H), 0.78 (t, J ¼ 6.3 Hz, 6H); 13C NMR (75 MHz, D2O)
d:
71.6, 68.7, 62.5, 61.3, 56.5, 45.3, 28.8, 25.5, 20.4, 20.4; HRMS (m/z):
calc for C10H21NOþ3 H: 204.15997, found: 204.15942.
(36.5 mg, 42%). 1H NMR (300 MHz, D2O)
d: 3.71 (m, 2H), 3.65e3.51
(m, 2H), 2.92 (dd, J ¼ 9.0, 4.5 Hz,1H), 2.55 (m, 2H), 2.45 (m, 2H),1.81
5.2.10.28. Synthesis of (2S,3S,4R)-1-isobutyl-2-(hydroxymethyl)
piperidine-3,4-diol (6p-3R). 5p-3R (199.0 mg, 0.42 mmol). Purified
(m,1H),1.38 (m, 3H), 0.74 (t, J ¼ 7.4 Hz, 3H); 13C NMR (75 MHz, D2O)

222
F. Jiang et al. / European Journal of Medicinal Chemistry 77 (2014) 211e222
by RP-HPLC (methanol:H2O ¼ 3:2, V:V) to give 6p-3R as white solid
(69.3 mg, 81.2%). 1H NMR (300 MHz, D2O)
: 3.90 (m, 1H), 3.73 (dd,
Acknowledgments
d
J ¼ 7.7, 3.2 Hz, 2H), 3.60 (m, 1H), 2.66 (dd, J ¼ 10.5, 5.8 Hz,1H), 2.35e
This research was financially supported by Guangdong Provin-
cial Project of Science and Technology (No. 2010A030100006), the
State Key Laboratory of Drug Research (SIMM1302KF-12 and
1004KF-15), the National Natural Science Foundation of China (No.
81172982) and 863 program (2012AA020302).
2.47 (m, 3H), 2.18 (dd, J ¼ 12.8, 4.9 Hz, 2H), 1.69e1.73 (m, 3H), 0.78e
0.80 (m, 6H); 13C NMR (75 MHz, D2O)
d: 68.5, 67.0, 62.9, 61.5, 58.4,
45.5, 27.8, 25.2, 20.9, 20.4; ESI-MS (m/z): 204.2[M þ H]þ, 226.2
[M þ Na]þ; HRMS (m/z): calc for C10H21NOþ3 H: 204.15997, found:
204.15998.
Appendix A. Supplementary data
5.2.10.29. Synthesis of (2S,3R,4R)-1-hydroethyl-2-(hydroxymethyl)
piperidine-3,4-diol (6q-3S). 5q-3S (165.6 mg, 0.36 mmol). Purified
by RP-HPLC (methanol:H2O ¼ 5:95, V:V) to give 6q-3S as white
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.ejmech.2014.03.004.
solid (31.6 mg, 46%). 1H NMR (300 MHz, D2O)
d: 3.73 (m, 2H), 3.68e
3.50 (m, 4H), 2.94 (m, 1H), 2.73 (t, J ¼ 6.1 Hz), 2.61 (m, 2H), 1.80 (m,
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5.2.10.33. Synthesis of (2S,3R,4R)-1-(2-(thiophen-2-yl)ethyl)-2-
(hydroxymethyl) piperidine-3,4-diol (6s-3S). 5s-3S (237.2 mg,
0.45 mmol). Purified by RP-HPLC (methanol:H2O ¼ 5:95, V:V) to
give 6s-3S as white solid (35.8 mg, 58.2%). 1H NMR (300 MHz,
CD3OD)
d
: 7.36 (d, J ¼ 3.6 Hz, 1H), 6.67 (d, J ¼ 3.6 Hz, 1H), 3.88e3.73
(m, 2H), 3.70 (dd, J ¼ 6.8, 3.8 Hz, 1H), 3.64 (td, J ¼ 7.1, 3.8 Hz, 1H),
3.02e2.90 (m, 5H), 2.77e2.68 (m, 2H), 2.02e1.87 (m, 1H), 1.64e1.49
(m, 1H); 13C NMR (75 MHz, D2O)
d
: 147.0, 129.2, 128.5, 124.7, 72.3,
68.6, 61.9, 58.5, 55.4, 45.1, 29.3, 27.2; HRMS (m/z): calcd for
12H19NO3S þ H: 258.11639, found: 258.11597.
C