Synthesis of polyhydroxylated piperidines and evaluation as glycosidase inhibitors

Article abstract of DOI:10.1016/j.bmc.2004.07.039

A series of 16 new chiral nonracemic polyhydroxylated piperidines was synthesized utilizing several chiral β-amino-alcohols. They act as a nitrogen source, chirality inducer and iminium stabilizer, in the desymmetrization of meso-trihydroxylated glutaraldehyde. The biological activity of these compounds towards several glycosidases (α-d-glucosidase, α-d-mannosidase, α-l-fucosidase) has been evaluated.

Full text of DOI:10.1016/j.bmc.2004.07.039

Bioorganic & Medicinal Chemistry 12 (2004) 5091–5097
Synthesis of polyhydroxylated piperidines and
evaluation as glycosidase inhibitors
a
a
Tony Tite,a Marie-Christine Lallemand,a, Erwan Poupon, Nicole Kunesch,
*
Franc¸ois Tillequin,a Christine Gravier-Pelletier,b Yves Le Merrerb
and Henri-Philippe Hussonc,
*
a
´ ´ `
Laboratoire de Pharmacognosie, Faculte des Sciences Pharmaceutiques et Biologiques, UMR 8638 associee au CNRS et a l’Universite
Rene Descartes, 4, Avenue de l’Observatoire, 75270 Paris Cedex 06, France
´
´
b
´
` ´ ´
Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 associee au CNRS et a l’Universite Rene
`
Descartes, 45, rue des Saints-Peres, 75270 Paris Cedex 06, France
´
c
´
´
Laboratoire de Chimie Therapeutique, Faculte des Sciences Pharmaceutiques et Biologiques, UMR 8638 associee au CNRS et
´
` ´
a l’Universite Rene Descartes, 4, Avenue de l’Observatoire, 75270 Paris Cedex 06, France
Received 13 April 2004; accepted 16 July 2004
Available online 12 August 2004
Abstract—A series of 16 new chiral nonracemic polyhydroxylated piperidines was synthesized utilizing several chiral b-amino-alco-
hols. They act as a nitrogen source, chirality inducer and iminium stabilizer, in the desymmetrization of meso-trihydroxylated
glutaraldehyde. The biological activity of these compounds towards several glycosidases (a-D-glucosidase, a-D-mannosidase, a-L-
fucosidase) has been evaluated.
ꢀ 2004 Elsevier Ltd. All rights reserved.
1. Introduction
OH
NH2
NH2
NH2
2 HCl
OH
2 HCl
OH
H
H
N
H
N
H
N
N
6
5
Glycosidases are involved in several metabolic pathways
and the development of inhibitors is an important chal-
lenge towards the treatment of diseases,1 such as diabe-
tes, cancer and viral infections including AIDS. In
recent years, polyhydroxylated piperidine alkaloids have
attracted much attention due to the ability of some of
them to act as selective glycosidase inhibitors.2 The high
therapeutic potential of these alkaloids has prompted
considerable efforts towards their structural modifica-
tions, most notably for the natural azasugar 1-deoxyno-
jirimycin 1 (Fig. 1). A first success is being recorded:
N-butyl-1-deoxynojirimycin has recently been approved
by the EMEA (European Agency for the Evaluation of
Medicinal Products) for the treatment of type 1 Gaucher
disease, a severe lysosomal disorder.3 New exciting
applications are being investigated. For example N-alkyl-
iminosugar analogs have been found to reversibly in-
HO
OH HO
HO
HO
OH
OH
OH
OH
OH
deoxynojirimycin 1
2
3
4
Figure 1.
duce infertility in male mice, opening the way to a
nonhormonal approach to male contraception.4 Consid-
ering the high potential of so called ÔazasugarsÕ for drug
discovery, several approaches have been made for the
modification of 1, such as the introduction at specific
positions on the piperidine ring system of fluoro,5 alkyl6
and acyl,7 amino8 and glucosyl substituents.9 The syn-
thesis of bicyclic diazasugars has also been reported.10
In a preliminary note,11 we disclosed the facile four steps
synthesis of amino derivatives 2 and 3 (Fig. 1), in the 1-
deoxynojirimycin series, from commercially available
starting material. The strategy used for the synthesis of
these compounds 2 and 3 involved the well established
CN(R,S) method.12
Keywords: Chiral nonracemic polyhydroxylated piperidines; Biological
activities; Glycosidases.
*
Corresponding authors. Tel.: +33 153739811; fax: +33 140469658;
e-mail: marie-christine.lallemand@univ-paris5.fr
0968-0896/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2004.07.039

5092
T. Tite et al. / Bioorg. Med. Chem. 12 (2004) 5091–5097
Ph
It is based upon the condensation of glutaraldehyde
with a phenylglycinol in the presence of KCN, furnish-
ing the N-cyanomethyloxazolidine system. The main-
spring of the CN(R,S) method is a remarkable
stereocontrol of the formation of a new chiral R or S
centre by CN elimination. Furthermore in specific cases,
the cyano group can be retained and used for its genius
reactivity. The use of phenylglycinol allowed the hydro-
genolysis of the chiral nitrogen protective group to
obtain NH derivatives 2 and 3.
Ph
Ph
3'
2'
OH
N
O
O
N
NC
HO
N
NC
HO
N
HO
OH
OH
OH
OH
OH
OH
5
6a
6b
Figure 2.
Compounds 2 and 3 have been evaluated as glycosidase
inhibitors: both derivatives were inactive on the a and b-
glycosidase studied (Ki around 10À3 M). Recently, when
screened against five common glycosidases (a-glucosi-
dase, b-glucosidase, a-galactosidase, a-mannosidase,
a-L-fucosidase)13 the same results were observed for 6-
amino-6-deoxy-1,5-imino-D-mannitol 4 (Fig. 1).
b-glucosidases from almonds and Caldocellum saccharo-
lyticum, with Ki values of 1.2 and 0.11nM, respectively.
2. Results and discussion
Then we decided to synthesize N-substituted derivatives
using other amino-alcohols allowing the introduction of
hydrophobic or/and flexible substituents at different
positions of the oxazolidine ring.
In order to design more active and more specific enzyme
inhibitors, we took advantage in VasellaÕs studies,
reporting recent insights into inhibition, structure and
mechanism of configuration-retaining glycosidases.14
More recently, the authors showed15 that C-2-substi-
tuted tetrahydroimidazopyridines 5 (Fig. 2) presented
a very strong inhibition of glucosidases. The introduc-
tion of a hydrophobic and flexible substituent such as
phenylethyl, led to a very strong inhibition against
Our project was based on the utilization of b-amino-
alcohols derived from commercially available L and D
amino-acids.16 They act as a nitrogen source, chirality
inducer and iminium stabilizer in the desymmetrization
of meso-trihydroxylated glutaraldehyde 7 (Scheme 1).
The CN group will not be hydrolyzed or reduced in this
Ph
Ph
O
Ph
O
OH
NC
HO
N
NC
N
NH2
+
(eq. 1)
KCN, Citric Acid
ZnBr2
OH HO
Ph
OH
OH
8a
OH
8c
Ph
Me
Me
OH
O
NC
HO
N
NH2
(eq. 2)
9a
KCN, Citric Acid
ZnBr2
OH
OH
Ph
Ph
N
Ph
O
O
OH
O
O
NC
N
NC
(eq. 3)
NH2
+
HO
OH
KCN, Citric Acid
ZnBr2
HO
OH HO
OH
OH
OH
10a
OH
10b
7
OH
Ph
Ph
O
S
S
Ph
S
O
NC
N
NC
N
NH2
(eq. 4)
+
KCN, Citric Acid
ZnBr2
HO
OH
HO
OH
OH
11a
OH
11b
OH
NH NH2
HN
N
O
NC
HO
12a
(eq. 5)
KCN, Citric Acid
ZnBr2
OH
OH
Scheme 1.

T. Tite et al. / Bioorg. Med. Chem. 12 (2004) 5091–5097
5093
new series albeit it will be envisioned in the future since
O
O
Dowex
15 h
60 ˚C
modulation of the pK of the piperidine nitrogen atom is
an important parameter for the structure–activity rela-
tionship studies.
O
O
O
O
O
ref 19
O
O
HO
OH
BnO
16
O
BnO
O
OBn
17
18
The condensations in the L-series when performed in an
aqueous citric acid buffer containing potassium cyanide,
afforded a crude material, which was then equilibrated
in the presence of zinc bromide to the more thermody-
namically stable derivatives 8a–12a as the major prod-
ucts (10–35%). Compounds 8a–11a possess an axial
cyano group, a stable trans-oxazolidine and three hyd-
roxyl groups in equatorial position. In some cases
(Eqs. 3 and 4) the thermodynamically less-stable com-
pounds (10b and 11b), which displaying axial protons
for all hydroxyl groups, were isolated in minute
amounts. In the first note,11 it was described that only
two (6a and 6b, Fig. 2) of the eight possible stereomers
of the cyclization products were isolated. We have more
closely examinated this reaction and have found that an-
other stereomer 6c was also formed. A benzylation reac-
tion was necessary to separate compounds 6 and to fully
characterize 6c (Fig. 3). A careful analysis by 1D or 2D
1H NMR analysis established the structure and stereo-
chemistry of 13c. In particular, the coupling constants
JH-6/H-7, JH-7/H-8 = 9Hz and JH-8/H-9 = 8Hz were
characteristic of an axial relationship between H-6,
H-7, H-8 and H-9, while JH-5/H-6 = 5.5Hz showed an
equatorial/axial relationship between H-5 and H-6.
For the other condensations, we isolated the stereomer
c only in the case of L-phenylethanolamine (Eq. 1). It
should be noticed that for each reaction, we were not
able to isolate all diastereomers a, b and c.
Ph
Ph
S
S
Ph
S
OH
O
O
NC
HO
N
NC
HO
N
NH2
+
KCN, Citric Acid
ZnBr2
OH
OH
OBn
19a
OBn
19b
Scheme 2.
(Fig. 4), in addition to the two expected stereomers
11a and 11b.
Characteristic features of the 13C NMR spectrum of 15
included a carbonyl resonance at 174ppm and a de-
shielded signal at 62.9ppm corresponding to C-1.
The IR spectrum showed a signal at 1747cmÀ1, charac-
teristic of a carbonyl function. The obtention of 6-oxa-2-
aza-bicyclo[3.2.1]octan-7-one derivative 15 was surpris-
ing because we had never observed such a cyclization
with all other amino-alcohols. This difference in behav-
iour could be attributed to the presence of the sulfur
atom and to a concerted mechanism. The sulfur atom
may activate, via a potential six member ring, the attack
of the OH at the position 4 onto the nitrile group, and
allows further hydrolysis of the resulting imine.
In the case of L-tryptophanol (Eq. 5) we observed the
formation of product 12a as a unique diastereomer in
20% yield. Nevertheless, formation of a by-product
14 resulting from the Pictet–Spengler condensation
and the addition of cyanide, was also obtained (Fig.
4). Treatment of meso-trihydroxylated glutaraldehyde
In good agreement with the proposal intramolecular
process, when the 2,4-dihydroxy-3-O-benzyl-pentandial
18 (Scheme 2), synthesized via a slightly modified litera-
ture procedure,17 was used instead of 7, only the
expected nitrile derivatives 19a and 19b were obtained.
7 and S-benzyl-cysteinol under acidic conditions
(Scheme 1, Eq. 4), afforded as well a by-product 15
The same condensation reaction with a D-amino-alcohol
as the starting material, such as D-norephedrine (Eq. 6),
D-phenylalaninol (Eq. 7) or D-tryptophanol (Eq. 8) was
also performed (Scheme 3).
5.5 Hz
Ph
Ph
2
H6
H8
3
H5
1
O
O
3. Inhibition studies
NC
HO
N
NC
N
9
9 Hz R
R
N
O
5
6
8
Ph
7
OH
BnO
OBn
R
CN
The new polyhydroxylated piperidines were screened
against three common glycosidases (a-D-glucosidase
from Bacillus stearothermophilus, a-D-mannosidase from
Jack beans and a-L-fucosidase from bovine kidney) and
biological evaluations were carried out as reported in the
literature,18 excepted for the a-L-fucosidase assays,
which were run at 31ꢁC. The observed results are gath-
ered in Table 1 and compared with the reported activity
of the 1-deoxynojirimycin 1.
8 Hz
OH
6c (15 %)
OBn
13c
H7
9 Hz
H9
R = OBn
Figure 3.
OH
CN
OH
Ph
S
N
O
N
N
O
H
The compounds in this study were found to be more
effective against a-glucosidase than against the other
tested enzymes. The selectivity can be attributed to the
fact that they have a similar configuration of the hydr-
oxyl groups. However, even if compounds 6 revealed
HO
OH
HO
O
OH
14
15
Figure 4.

5094
T. Tite et al. / Bioorg. Med. Chem. 12 (2004) 5091–5097
Ph
Ph
O
Ph
O
Me
Me
Me
OH
NC
HO
N
NC
HO
N
NH2
(eq. 6)
+
KCN, Citric Acid
ZnBr2
OH
OH
OH
OH
20a
20b
Ph
N
Ph
OH
O
NC
HO
NH2
(eq. 7)
7
KCN, Citric Acid
ZnBr2
OH
OH
21a
OH
NH NH2
OH
CN
NC
O
N
N
N
H
N
+
(eq. 8)
H
KCN, Citric Acid
ZnBr2
HO
OH
HO
OH
OH
OH
22
23
Scheme 3.
Table 1. Comparison of inhibitory activities for deoxynojirimycin 1 and polyhydroxylated piperidines
Compounds No.
a-D-Glucosidase
a-D-Mannosidase
a-L-Fucosidase
1
0.44 lM
140 lM
45
––
30
––
10
2
3
6a
33
16
34
22
NIa
50
70
6b
8a
21
10
5
NI
NI
8c
9a
NI
NI
NI
NI
NI
NI
10a
10b
11a
11b
12a
14
NI
8
24
13
NI
23
77 lM
No soluble
700 lM
200 lM
NI
12
No soluble
No soluble
NI
NI
NI
17
6
20a
20b
21a
22
NI
NI
NI
NI
21
19
NI
NI
NI
20
730 lM
290 lM
23 (%)
10
Percentage of inhibitions at 1mM and Ki in lM (in bold) when measured.
a NI = no inhibition detected.
slight inhibition of a-D-glucosidase (50% and 70% for 6a
and 6b, respectively), the absence of inhibition observed
for derivatives 8, 9a and 10 shows that introducing the
phenyl substitute at different positions on the oxazol-
idine ring did not increase the inhibition. More encour-
aging results were obtained with compounds 11a, 14
and 23. The better values observed, justifies the
development of more hydrosoluble products in order
to generate more potent inhibitors. It must be notified
that the best result was obtained with compound 11a,
possessing the more hydrophobic flexible group, as sug-
gested by Vasella. We now envision the reduction of the
cyano group to an amine function. This synthetic work
is in progress, and the results will be reported in due
course.
4. Conclusion
Short and efficient synthesis of diversely functionalized
piperidines has been carried out from commercially
available starting materials. Sixteen new products have
been obtained and some tested for their inhibition activ-
ities towards three glycosidases. This work demonstrates
that inhibition activity of glucosidases of 1-deoxynojiri-
mycin amino analogues 2 and 3, which are weak inhib-
itors, can be increased to potent and selective inhibitors
by simply linking a substituted oxazolidine ring to a
hydrophobic and flexible group such as compounds
11a. Our chemical modifications are currently being
extended to transformations of the cyano functional
group.

T. Tite et al. / Bioorg. Med. Chem. 12 (2004) 5091–5097
5095
5. Experimental
5.1. General methods
d 52.4 (C-5), 57.8 (C-3), 71.5 (C-6), 75.3 (C-8), 76.2
(C-7), 80.8 (C-2), 93.7 (C-9), 115.4 (CN), 127.7, 128.4,
129.5 (CH arom), 142.1 (Cq arom). MS (CI), NH3:
m/z 277 (M+1)+.
IR spectra (max in cmÀ1) were obtained on a Nicole et
1
FT-IR instrument. H NMR (d [ppm], J [Hz]) and 13C
5.5. Hexahydro-2-phenyl-3-methyl-6,7,8-trihydroxy-2R-
3R-[2a,3a,5b,6b,7a,8b,8ab]-5H-oxazolo[3,2-a]pyridine-5-
carbonitrile (9a)
NMR spectra were recorded at 400 and 100MHz,
respectively, using a Bruker Avance 400 spectrometer.
When necessary, the signals were unambiguously
assigned by 2D NMR techniques: COSY, NOESY,
HMQC and HMBC. These experiments were performed
using standard Bruker microprograms. Mass spectra
were recorded with a Nermag R-10-10C spectrometer
using chemical ionization technique (reagent gas: NH3)
(CI/MS) and with a ZQ 2000 Waters using a Zspray
(ESI-MS). Optical rotations were measured on a Per-
kin–Elmer 141C polarimeter with sodium lamp
(589nm) at 20ꢁC. Column chromatographies were con-
ducted using silica gel 60 Merck (35–70m) with an over-
pressure of 200mbar.
Oil, Rf 0.33 (CH2Cl2/MeOH, 9:1). [a]D À3.5 (c 1,
1
MeOH). H NMR (CDCl3): d 0.63 (d, 3H, J = 6.5Hz,
Me), 3.26 (dd, 1H, J = 6.5, 8Hz, H-3), 3.5–3.6 (m, 2H,
H-7 and H-8), 3.80 (dd, 1H, J = 6, 9Hz, H-6), 4.06 (d,
1H, J = 7.5Hz, H-9), 4.33 (d, 1H, J = 6Hz, H-5), 5.20
(d, 1H, J = 8Hz, H-2), 7.1–7.6 (m, 5H arom); 13C
NMR (CDCl3): d 13.7 (CH3), 52.5 (C-5), 59.0 (C-3),
71.7 (C-6), 74.9 (C-8), 76.2 (C-7), 84.4 (C-2), 93.O (C-
9), 115.0 (CN), 127.3, 128.3, 128.8 (CH arom), 140.2
(Cq arom). MS (CI), NH3: m/z 291 (M+1)+.
5.6. Hexahydro-3-benzyl-6,7,8-trihydroxy-3R-[3a,5b,6b,
7a,8b,8ab]-5H-oxazolo[3,2-a]pyridine-5-carbonitrile
(10a)
5.2. General procedure for the coupling reaction between
amino-alcohol and meso-trihydroxylated glutaraldehyde
The meso-trihydroxylated glutaraldehyde 7 (20mmole)
was added to an aqueous citric acid (4%) solution of
the amino-alcohol (10mmole). The potassium cyanide
(15mmole) was added and the resulting mixture was
stirred at rt for 15h. The mixture was then carefully neu-
tralized with NaHCO3 and concentrated in vacuum. The
residue was triturated in boiling methanol (3 · 150mL)
affording precipitation of brown solids, which were fil-
tered on silica gel. The resulting solutions were collected
and concentrated. The obtained oil was rediluted in
methanol and ZnBr2 (2.21mmole, 500mg) was added.
After 4h, the mixture was concentrated and the residue
was purified by flash chromatography.
Oil, Rf 0.32 (CH2Cl2/MeOH, 9:1). [a]D +23.5 (c 1,
MeOH). IR (KBr) cmÀ1, 3366 (OH), 2229 (CN). 1H
NMR (CDCl3/DMSO-d6: 2:1): d 2.04 (dd, 1H, J = 7.5,
13.5Hz, H-10), 2.29 (dd, 1H, J = 5.5, 13.5Hz, H-10),
2.5–2.8 (m, 3H, H-3, H-7 and H-8), 2.9–3.0 (m, 1H,
H-6), 3.06 (t, 1H, J = 8Hz, H-2), 3.27 (d, 1H,
J = 8Hz, H-9), 3.31 (t, 1H, J = 8Hz, H-2), 3.47 (d,
1H, J = 5.5Hz, H-5), 4.4–4.5 (b s, OH-7), 4.56 (d, 1H,
J = 4Hz, OH-8), 5.0–5.2 (b s, OH-6), 6.5–6.8 (m, 5H
arom); 13C NMR (CDCl3/DMSO-d6: 2:1): d 37.2 (C-
10), 51.2 (C-5), 58.4 (C-3), 69.9 (C-6), 70.9 (C-2), 72.8
(C-8), 74.5 (C-7), 91.9 (C-9), 114.3 (CN), 126.1, 128.1,
128.3 (CH arom), 136.9 (Cq arom). MS (CI), NH3:
m/z 291 (M+1)+.
5.3. Hexahydro-2-phenyl-6,7,8-trihydroxy-2R-[2a,5b,6b,
7a,8b,8ab]-5H-oxazolo[3,2-a]pyridine-5-carbonitrile (8a)
5.7. Hexahydro-3-benzyl-6,7,8-trihydroxy-3R-[3a,5b,6a,
7b,8a,8ab]-5H-oxazolo[3,2-a]pyridine-5-carbonitrile
(10b)
Oil, Rf 0.30 (CH2Cl2/MeOH, 9:1). [a]D À17.5 (c 1,
1
MeOH). IR (KBr) cmÀ1, 3405 (OH), 2229 (CN). H
NMR (MeOD): d 3.06 (dd, 1H, J = 2.5, 8.5Hz, H-3),
3.23 (t, 1H, J = 8.5Hz, H-3), 3.5–3.6 (m, 2H, H-7 and
H-8), 3.80 (dd, 1H, J = 6, 9Hz, H-6), 4.03 (d, 1H,
J = 7.5Hz, H-9), 4.41 (d, 1H, J = 6Hz, H-5), 5.20 (dd,
1H, J = 2.5, 8.5Hz, H-2), 7.2–7.5 (m, 5H arom); 13C
NMR (MeOD): d 54.2 (C-5), 56.5 (C-3), 71.5 (C-6),
75.0 (C-8), 76.1 (C-7), 80.2 (C-2), 93.5 (C-9), 115.4
(CN), 127.2, 128.7, 129.3 (CH arom), 143.6 (Cq arom).
MS (CI), NH3: m/z 277 (M+1)+.
Oil, Rf 0.39 (CH2Cl2/MeOH, 9:1). 1H NMR (MeOD): d
2.81 (dd, 1H, J = 7.5, 13.5Hz, H-10), 3.09 (dd, 1H,
J = 7.5, 13.5Hz, H-10), 3.33 (m, 1H, H-3), 3.77 (t, 1H,
J = 7.5Hz, H-2), 3.9–4.0 (m, 3H, H-2, H-6 and H-8),
4.09 (t, 1H, J = 3.5Hz, H-7), 4.28 (d, 1H, J = 2Hz,
H-5), 4.40 (d, 1H, J = 1.5 Hz, H-9), 7.1–7.5 (m, 5H
arom); 13C NMR (CDCl3): d 38.0 (C-10), 52.8 (C-5),
60.8 (C-3), 70.3 (C-6), 71.8 (C-8), 72.0 (C-7), 72.1 (C-
2), 89.7 (C-9), 115.9 (CN), 127.7, 129.6, 130.2 (CH
arom), 139.1 (Cq arom). MS (CI), NH3: m/z 291
(M+1)+.
5.4. Hexahydro-2-phenyl-6,7,8-trihydroxy-2R-[2a,5a,6a,
7b,8a,8aa]-5H-oxazolo[3,2-a]pyridine-5-carbonitrile (8c)
5.8. Hexahydro-3-benzylsulfanylmethyl-6,7,8-trihydroxy-
3R-[3a,5b,6b,7a,8b,8ab]-5H-oxazolo[3,2-a]pyridine-5-
carbonitrile (11a)
Oil, Rf 0.27 (CH2Cl2/MeOH, 9:1). [a]D À18.0 (c 1,
MeOH). 1H NMR (MeOD): d 2.72 (t, 1H, J = 9Hz,
H-3), 3.40 (dd, 1H, J = 7.5, 9Hz, H-8), 3.49 (t, 1H,
J = 9Hz, H-7), 3.62 (dd, 1H, J = 6, 9Hz, H-3), 3.79
(dd, 1H, J = 6, 9Hz, H-6), 4.20 (d, 1H, J = 7.5Hz, H-
9), 4.50 (d, 1H, J = 6Hz, H-5), 5.20 (dd, 1H, J = 6,
9Hz, H-2), 7.2–7.4 (m, 5H arom); 13C NMR (MeOD):
Oil, Rf 0.33 (CH2Cl2/MeOH, 9:1). [a]D +32.0 (c 1,
MeOH). IR (KBr) cmÀ1, 3382 (OH), 2229 (CN). 1H
NMR (MeOD): d 2.51 (dd, 1H, J = 7, 13.5Hz, H-10),
2.64 (dd, 1H, J = 5, 13.5Hz, H-10), 3.0–3.1 (m, 1H,

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T. Tite et al. / Bioorg. Med. Chem. 12 (2004) 5091–5097
H-3), 3.26 (dd, 1H, J = 8, 9Hz, H-8), 3.40 (t, 1H,
J = 9Hz, H-7), 3.65 (dd, 1H, J = 6, 9Hz, H-6), 3.71
(dd, 1H, J = 7, 8Hz, H-2), 3.76 (d, 1H, J = 13.5Hz, H-
11), 3.81 (d, 1H, J = 13.5Hz, H-11), 3.92 (d, 1H,
J = 8Hz, H-9), 4.07 (t, 1H, J = 8Hz, H-2), 4.48 (d,
1H, J = 6Hz, H-5), 7.2–7.4 (m, 5H arom); 13C NMR
(MeOD): d 33.5 (C-10), 37.2 (C-11), 53.2 (C-5), 58.3
(C-3), 71.6 (C-6), 72.8 (C-2), 74.9 (C-8), 76.1 (C-7),
93.8 (C-9), 115.7 (CN), 128.2, 129.6, 130.1 (CH arom),
139.6 (Cq arom). MS (CI), NH3: m/z 337 (M+1)+.
HMRS calcd for C16H20N2O4S 337.1222, found
337.1210.
J = 6.5, 8Hz, H-2), 4.71 (2dAB, 2H, J = 12Hz, O–
CH2–Ph), 4.88 (s, 2H, O–CH2–Ph), 4.91 (d, 2H,
J = 11.5Hz, O–CH2–Ph), 4.92 (d, 2H, J = 7.5Hz, H-
9), 7.1–7.6 (m, 20H arom); 13C NMR (CDCl3): d
47.8 (C-5), 63.1 (C-3), 73.4 (O–CH2–Ph), 73.7 (C-2),
74.0 (O–CH2–Ph), 75.9 (C-6), 76.1 (O–CH2–Ph), 81.3
(C-7), 81.6 (C-8), 90.8 (C-9), 115.2 (CN), 126–130 (CH
arom), 136–139 (Cq arom). MS (CI), NH3: m/z 547
(M+1)+.
5.12. 1,2,3-Trihydroxy-6-hydroxymethyl-1,2,3,4,6,7,12,
12b-octahydro-indolo[2,3-a]quinolizine-4-carbonitrile (14)
5.9. Hexahydro-3-benzylsulfanylmethyl-6,7,8-trihydroxy-
3R-[3a,5b,6a,7b,8a,8ab]-5H-oxazolo[3,2-a]pyridine-5-
carbonitrile (11b)
Oil, Rf 0.18 (CH2Cl2/MeOH, 9:1). [a]D +1.5 (c 0.74,
MeOH). 1H NMR (MeOD): d 2.84 (dd, 1H, J = 7,
14.5Hz, H-7), 3.10 (dd, 1H, J = 6, 14.5Hz, H-7),
3.3–3.4 (m, 1H, H-3), 3.4–3.5 (m, 2H, H-2 and H-6),
3.66 (dd, 1H, J = 6, 9Hz, H-1), 3.78 (t, 1H, J = 8Hz,
CH2–OH), 3.94 (d, 1H, J = 8Hz, H-3), 4.02 (t, 1H,
J = 8Hz, CH2–OH), 4.25 (d, 1H, J = 6Hz, H-12),
6.9–7.7 (m, 4H, H arom); 13C NMR (MeOD): d 18.5
(C-7), 53.6 (C-11), 56.1 (C-3), 59.2 (C-6), 63.1
(CH2–OH), 73.1 (C-1), 73.5 (C-3), 74.9 (C-2), 112.2,
118.6, 119.9, 122.5 (CH arom), 106.5, 119.6, 128.1,
130.0, 146.6 (CN and Cq arom). MS (CI), m/z 352
(M+Na)+.
Rf 0.38 (CH2Cl2/MeOH, 9:1). [a]D +73.0 (c 1, MeOH).
IR (KBr) cmÀ1, 3426 (OH), 2230 (CN). 1H NMR
(MeOD): d 2.55 (dd, 1H, J = 7, 13.5Hz, H-10), 2.72
(dd, 1H, J = 5, 13.5Hz, H-10), 3.2–3.3 (m, 1H, H-3),
3.71 (dd, 1H, J = 7.5, 8Hz, H-2), 3.78 (d, 1H,
J = 13.5Hz, H-11), 3.84 (d, 1H, J = 13.5Hz, H-11),
3.8–3.9 (m, 2H, H-6 and H-8), 4.02 (t, 1H, J = 3Hz,
H-7), 4.08 (t, 1H, J = 8Hz, H-2), 4.42 (d, 1H,
J = 1Hz, H-9), 4.45 (d, 1H, J = 2Hz, H-5), 7.2–7.4 (m,
5H arom); 13C NMR (MeOD): d 33.0 (C-10), 37.3 (C-
11), 53.0 (C4-5), 58.4 (C-3), 70.3 (C-6), 71.9 (C-2), 72.0
(C-7 and C-8), 89.7 (C-9), 116.1 (CN), 128.1, 129.5,
130.1 (CH arom), 139.6 (Cq arom). MS (CI), NH3:
m/z 337 (M+1)+.
5.13. 3-Benzylsulfanylmethyl-7,11-dihydroxy-5,9-dioxa-
2-aza-tricyclo[6.2.1]undecan-10-one (15)
Oil, Rf 0.36 (CH2Cl2/MeOH, 9:1). [a]D À5.0 (c 1,
MeOH). IR (KBr) cmÀ1, 3414 (OH), 1747 (CO). 1H
NMR (CDCl3): d 2.47 (dd, 1H, J = 6.5, 13.5Hz, H-
10), 2.56 (dd, 1H, J = 6.5, 13.5Hz, H-10), 3.2–3.3 (m,
1H, H-3), 3.44 (dd, 1H, J = 7.5, 9Hz, H-2), 3.55 (d,
1H, J = 3.0Hz, H-5), 3.76 (dd, 2H, J = 13.5Hz, H-11),
3.8–3.9 (m, 2H, H-6 and H-7), 4.03 (dd, 1H, J = 6.54,
9Hz, H-2), 4.61 (d, 1H, J = 4Hz, H-8), 4.95 (s, 1H, H-
9), 7.2–7.4 (m, 5H arom); 13C NMR (CDCl3): d 34.9
(C-10), 37.1 (C-11), 64.2 (C-3), 64.9 (C-5), 70.9 (C-2),
73.5 (C-7), 76.1 (C-6), 77.9 (C-8), 88.0 (C-9), 126–130
(CH arom), 136–139 (Cq arom), 171.9 (CO). MS (CI),
NH3: m/z 338 (M+1)+.
5.10. Hexahydro-6,7,8-trihydroxy-3-(1H-indol-3-methyl)-
3R-[3a,5b,6b,7a,8b,8ab]-5H-oxazolo[3,2-a]pyridine-5-
carbonitrile (12a)
Oil, Rf 0.23 (CH2Cl2/MeOH, 9:1). [a]D À12.5 (c 0.92,
MeOH). 1H NMR (MeOD): d 2.84 (dd, 1H, J = 7,
14.5Hz, H-10), 3.10 (dd, 1H, J = 6, 14.5Hz, H-10),
3.3–3.4 (m, 1H, H-8), 3.4–3.5 (m, 2H, H-3 and H-7),
3.66 (dd, 1H, J = 6, 9Hz, H-6), 3.78 (t, 1H, J = 8Hz,
H-2), 3.94 (d, 1H, J = 8Hz, H-9), 4.02 (t, 1H,
J = 8Hz, H-2), 4.25 (d, 1H, J = 6Hz, H-5), 7.03 (t,
1H, J = 7.5Hz, H arom), 7.11 (s, 1H, H arom), 7.12 (t,
1H, J = 7.5Hz, H arom), 7.35 (d, 1H, J = 8Hz, H
arom), 7.57 (d, 1H, J = 8Hz, H arom); 13C NMR
(MeOD): d 28.6 (C-10), 53.3 (C-5), 59.9 (C-3), 71.7
(C-6), 73.6 (C-2), 75.0 (C-8), 76.3 (C-7), 93.9 (C-9),
112.4, 119.2, 119.9, 122.6, 123.7 (CH arom), 111.6,
115.7, 128.4, 138.2 (Cq arom). MS (CI), NH3: m/z 330
(M+1)+.
5.14. Hexahydro-7-benzyloxy-3-benzylsulfanylmethyl-
6,8-dihydroxy-3R-[3a,5b,6b,7a,8b,8ab]-5H-oxazolo[3,2-
a]pyridine-5-carbonitrile (19a)
White powder, Rf 0.25 (CH2Cl2/MeOH, 18:1). [a]D
+28.5 (c 1, CHCl3). 1H NMR (CDCl3): d 2.44 (dd,
1H, J = 6.5, 13.5Hz, H-10), 2.48 (d, 1H, J = 2.5Hz,
OH-8), 2.51 (dd, 1H, J = 5.5, 13.5Hz, H-10), 2.55 (d,
1H, J = 2.5Hz, OH-6), 3.1–3.2 (m, 1H, H-3), 3.52 (t,
1H, J = 9Hz, H-7), 3.60 (t, 1H, J = 8.5Hz, H-8), 3.7–
3.8 (m, 2H, H-2 and H-11), 3.83 (t, 1H, J = 7Hz, H-
6), 4.08 (d, 1H, J = 8Hz, H-9), 4.13 (t, 1H, J = 8Hz,
H-2), 4.40 (d, 1H, J = 6Hz, H-5), 4.91 (dd, 2H,
J = 11.5Hz, HO–CH2–Ph), 7.2–7.5 (m, 10H arom);
13C NMR (CDCl3): d 32.3 (C-10), 36.4 (C-11), 50.9
(C-5), 56.5 (C-3), 70.2 (C-6), 72.0 (C-2), 74.3 (C-8),
75.6 (O–CH2–Ph), 82.7 (C-7), 92.3 (C-9), 114.0 (CN),
127–129 (CH arom), 137.4, 138.1 (Cq arom). MS (CI),
m/z 427 (M+H)+.
5.11. Hexahydro-6,7,8-tribenzyloxy-3-phenyl-3R-
[3a,5a,6a,7b,8a,8aa]-5H-oxazolo[3,2-a]pyridine-5-carbo-
nitrile (13c)
The benzylation reaction was effected by procedure
described in the literature.19 Oil, Rf10.31 (cyclohexane/
ether, 8:3). [a]D À24.0 (c 1, CHCl3). H NMR (CDCl3):
d 3.49 (dd, 1H, J = 8, 9Hz, H-8), 3.72 (dd, 1H, J = 5.5,
9Hz, H-6), 3.82 (t, 1H, J = 9Hz, H-7), 3.87 (d, 1H,
J = 5.5Hz, H-5), 4.08 (dd, 1H, J = 5.5, 8Hz,
H-2), 4.16 (t, 1H, J = 6Hz, H-3), 4.38 (dd, 1H,

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3. Butters, T. D.; Dwek, R. A.; Platt, F. M. Curr. Top. Med.
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4. Van der Spoel, A. C.; Jeyakumar, M.; Butters, T. D.;
Charlton, H. M.; Moore, H. D.; Dwek, R. A.; Platt, F. M.
Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 17173.
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Tetrahedron 1996, 52, 131.
6. Van den Broek, L. A. G. M.; Vermaas, D. J.; van
Kemenade, F. J.; Tan, M. C. C. A.; Rotteveel, F. T. M.;
Zandberg, P.; Butters, T. D.; Miedema, F.; Ploegh, H. L.;
van Boeckel, C. A. A. Recl. Trav. Chim. Pays-Bas 1994,
113, 507.
5.15. Hexahydro-7-benzyloxy-3-benzylsulfanylmethyl-
6,8-dihydroxy-3R-[3a,5b,6a,7b,8a,8ab]-5H-oxazolo[3,2-
a]pyridine-5-carbonitrile (19b)
Oil, Rf 0.47 (CH2Cl2/MeOH, 18:1). [a]D +103.0 (c 2,
1
CHCl3). H NMR (MeOD): d 2.53 (dd, 1H, J = 7.0,
13.5Hz, H-10), 2.68 (dd, 1H, J = 5, 13.5Hz, H-10),
3.1–3.2 (m, 1H, H-3), 3.70 (t, 1H, J = 8Hz, H-2), 3.76
(dd, 2H, J = 13.5Hz, H-11), 3.85 (s, 1H, H-7), 4.01 (d,
1H, J = 1.5Hz, H-8), 4.05 (t, 1H, J = 8Hz, H-2), 4.14
(s, 1H, H-6), 4.40 (s, 1H, H-9), 4.49 (s, 1H, H-5), 4.60
(dd, 2H, J = 12Hz, O–CH2–Ph), 7.2–7.5 (m, 10H arom);
13C NMR (MeOD): d 31.7 (C-10), 36.0 (C-11), 52.0 (C-
5), 57.0 (C-3), 67.2 (C-8), 67.7 (C-6), 70.7 (C-2), 71.9 (O–
CH2–Ph), 77.3 (C-7), 88.6 (C-9), 114.7 (CN), 127–129
(CH arom), 137.8, 138.3 (Cq arom). MS (CI), m/z 427
(M+H)+.
7. Delinck, D. L.; Margolin, A. L. Tetrahedron Lett. 1990,
31, 3093.
´
8. Fitremann, J.; Dureault, A.; Depezay, J.-C. Synlett 1995,
235.
5.16. Hexahydro-2-phenyl-3-methyl-6,7,8-trihydroxy-2S-
3S-[2b,3b,5a,6b,7a,8b,8ab]-5H-oxazolo[3,2-a]pyridine-5-
carbonitrile (20b)
9. Johns, B. A.; Pan, Y. T.; Elbei, A. D.; Johnson, C. R.
J. Am. Chem. Soc. 1997, 119, 4856.
10. Berges, D. A.; Ridges, M. D.; Dalley, N. K. J. Org. Chem.
1998, 63, 391.
Rf 0.42 (CH2Cl2/MeOH, 9:1). 1H NMR (CDCl3): d 0.76
(d, 3H, J = 6.5Hz, Me), 3.40 (dd, 1H, J = 6.5, 8Hz, H-
3), 4.12 (m, 1H, H-7), 4.18 (m, 1H, H-8), 4.25 (t, 1H,
J = 3.5Hz, H-6), 4.37 (d, 1H, J = 2.5Hz, H-5), 4.57 (d,
1H, J = 1.5Hz, H-9), 5.23 (d, 1H, J = 8Hz, H-2), 7.2–
7.6 (m, 5H arom); 13C NMR (CDCl3): d 13.7 (CH3),
52.4 (C-5), 59.1 (C-3), 70.4 (C-8), 71.9 (C-7), 72.3 (C-
6), 82.8 (C-2), 88.9 (C-9), 115.4 (CN), 128.7 128.8,
129.3 (CH arom), 140.7 (Cq arom). MS (CI), CH4: m/
z 291 (M+1)+.
11. Poupon, E.; Luong, B. X.; Chiaroni, A.; Kunesch, N.;
Husson, H.-P. J. Org. Chem. 2000, 65, 7208.
12. Husson, H.-P.; Royer J. Chem. Soc. Rev. 1999, 28,
383.
´
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Med. Chem. 2000, 8, 135.
14. Heightman, T. D.; Vasella, A. Angew. Chem., Int. Ed.
1999, 38, 750.
15. Panday, N.; Canac, Y.; Vasella, A. Helv. Chim. Acta 2000,
83, 58.
16. Abiko, A.; Masamune, S. Tetrahedron Lett. 1992, 33,
5517.
17. Barroca, N.; Jacquinet, J. C. Carbohydr. Res. 2000, 329,
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References and notes
18. Gravier-Pelletier, C.; Maton, W.; Dintinger, T.; Tellier,
C.; Le Merrer, Y. Tetrahedron 2003, 59, 8705.
19. Brimacombe, J. S.; Jones, B. D.; Stacey, M.; Willard, J. J.
Carbohydrate Res. 1996, 2, 167.
1. Martin, O. R.; Compain, P. Iminosugars: Recent Insights
into their Bioactivities and Potential as Therapeutic
Agents. In Current Topics in Medicinal Chemistry;