Concise syntheses of potent chaperone drug candidates, N-octyl-4-epi- β-valinenamine (NOEV) and its 6-deoxy derivative, from (+)-proto-quercitol

Article abstract of DOI:10.1016/j.carres.2012.12.010

Described are the efficient syntheses of β-galactose-type unsaturated carbasugar amine, N-octyl-4-epi-β-valienamine (1a, NOEV) and 6-deoxy NOEV (12), starting from (+)-proto-quercitol (2), which is readily provided by the bioconversion of myo-inositol. NOEV is a potent chemical chaperone drug candidate for G_M1-gangliosidosis. An intermediate alkadiene benzoate was prepared from 2 in five steps, with the key step being a Wittig reaction with an enol ester. The 6-deoxy derivative 12 was conveniently synthesized from the versatile intermediate dibromo compound 6, which was also an intermediate in the synthesis of NOEV. Enzyme inhibition assays demonstrated that 12 possessed stronger inhibitory activity than the parent 1a, suggesting that the C-6 position of the 4-epi-β-valienamine-type inhibitor could have hydrophobic interactions at the β-galactosidase active site residues.

Full text of DOI:10.1016/j.carres.2012.12.010

Carbohydrate Research 368 (2013) 8–15
Contents lists available at SciVerse ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Concise syntheses of potent chaperone drug candidates, N-octyl-4-
epi-b-valinenamine (NOEV) and its 6-deoxy derivative, from (+)-proto
-quercitol
a
b
Shinichi Kuno a, , Atsushi Takahashi , Seiichiro Ogawa
⇑
a Central Research Laboratories, Hokko Chemical Industry, Co., Ltd, Toda, Atsugi 243-0023, Japan
b Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 30 October 2012
Received in revised form 7 December 2012
Accepted 8 December 2012
Available online 19 December 2012
Described are the efficient syntheses of b-galactose-type unsaturated carbasugar amine, N-octyl-4-epi-b-
valienamine (1a, NOEV) and 6-deoxy NOEV (12), starting from (+)-proto-quercitol (2), which is readily
provided by the bioconversion of myo-inositol. NOEV is a potent chemical chaperone drug candidate
for GM1-gangliosidosis. An intermediate alkadiene benzoate was prepared from 2 in five steps, with
the key step being a Wittig reaction with an enol ester. The 6-deoxy derivative 12 was conveniently syn-
thesized from the versatile intermediate dibromo compound 6, which was also an intermediate in the
synthesis of NOEV. Enzyme inhibition assays demonstrated that 12 possessed stronger inhibitory activity
than the parent 1a, suggesting that the C-6 position of the 4-epi-b-valienamine-type inhibitor could have
hydrophobic interactions at the b-galactosidase active site residues.
Keywords:
Aminocyclitol
Carbasugar
Chemical chaperone
Glycosidase inhibitor
Quercitol
Ó 2012 Elsevier Ltd. All rights reserved.
Wittig reaction
1. Introduction
(NOV, 1b5), have been shown to possess potential curative effects
for b-galactosidase and b-glucosidase deficiencies, respectively
In some cases the activities of enzymes resulting from genetic
mutations can be raised using small amounts of inhibitors. This
paradoxical behavior can be taken advantage of for the treatment
of genetic lysosomal storage disease in a method referred to as
chemical chaperone therapy.1 Lowered activities of enzymes in
lysosomes may result in the accumulation of substrates inside
and outside of somatic cells, which can cause organ dysfunction.
However, enzymes can be stabilized by the introduction of small
molecular inhibitors and then transported to the lysosomes, where
they express their normal enzymatic activities. This therapeutic
strategy has been examined in an experimental model to treat
(Fig. 1). NOEV has been demonstrated to be a strong inhibitor of
human b-galactosidase (IC50 = 0.2
M4b) and bovine liver b-galac-
tosidase (IC50 = 4.5
M by NOEV hydrochloride4d) as well as a po-
l
l
tent chemical chaperone for in vitro and in vivo GM1
gangliosidosis models.4b
NOEV was first synthesized from NOV via epimerization at C-4
through an oxidation–reduction sequence.4a At that time, prepara-
tion of NOV was established via a versatile conjugate alkadiene de-
rived from an (ꢀ)-endo-adduct of furan and acrylic acid.
Alternatively, starting from the (+)-endo-adduct, an isomeric alk-
adiene suitable for the second-generation synthesis of NOEV was
effectively developed.1e,4c These routes recognized the wide adapt-
ability of the endo-adducts for carbasugar synthesis. However, to
access chiral carbasugars, optically pure endo-adducts have to be
prepared through a cumbersome optical resolution.6
Bioconversion of myo-inositol has been shown to produce opti-
cally pure deoxyinositols, quercitols. These are versatile starting
materials for the synthesis of several biologically active com-
pounds.7 Recently, our group has briefly reported a convenient
synthetic route to optically pure NOEV using the commercially
available deoxyinositol 2, (+)-proto-quercitol, as a chiral building
block and a new preparation of NOV from (ꢀ)-vibo-quercitol.4d
In this paper, synthesis of NOEV starting from (+)-proto-querc-
itol through a key protected alkadiene 5, which was successfully
some lysosomal diseases such as Fabry disease (
mutation), GM1 gangliosidosis and Morquio B disease (b-galactosi-
dase mutation), Pompe disease ( -glucosidase mutation) and Gau-
a-galactosidase
a
cher disease (b-glucosidase mutation) by using the corresponding
inhibitors as chemical chaperones.1d,2
We have previously synthesized several bioactive cyclitol deriv-
atives, resulting in the preparation of anhydro-quercitols, carba-
sugar amines, deoxyinosamines, and others.3 Among them,
valienamine-type unsaturated carbaglycosylamine derivatives, N-
octyl-4-epi-b-valienamine (NOEV, 1a4) and N-octyl-b-valienamine
⇑
Corresponding author. Tel.: +81 46 228 5881; fax: +81 46 228 0164.
E-mail address: kuno-s@hokkochem.co.jp (S. Kuno).
0008-6215/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.carres.2012.12.010

S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
9
OH
HO
HO
OH
HO
OH
NH(CH2)7CH3
HO
OH
HO
NH(CH2)7CH3
HO
HO
HO
OH
NOEV (1a)
NOV (1b)
(+)-
-Quercitol (2)
proto
Figure 1. N-Octyl-4-epi-b-valienamine (NOEV, 1a), N-octyl-b-valienamine (NOV, 1b), and (+)-proto-quercitol (2).
converted into NOEV via an
a
-bromo intermediate, an epoxide, or
(broad doublet, J = 10.1 Hz) and 6.32 (doublet of doublets, J = 1.8,
10.1 Hz) could be attributed to the alkene protons on the ring.
Moreover, the two ring protons attached to the isopropylidene
group appeared at d 4.37 (triplet, J = 5.3 Hz) and 4.76 (doublet,
J = 5.5 Hz); their coupling was confirmed in an H–H COSY measure-
ment, clearly supporting the proposed structure.
a mixture of both, is described in full detail along with the isolation
of the intermediates and determination of their chemical proper-
ties. Furthermore, synthesis of the 6-deoxy derivative 12 as the
hydrochloride was readily attainable using the versatile intermedi-
ate. The synthesis of 12 and its b-galactosidase inhibitory activity
are described herein.
It is known that enol-ester type lactones can be converted into
the corresponding enolates with reactive phosphoranes.8 In this
case, after formation of the enolate, elimination of the benzoate
may occur to give rise to the unsaturated ketone, which is succes-
sively methylenated by the phosphorous ylide to give 5 (Scheme 2).
This Wittig-type one-pot elimination of the benzoate and exo-olef-
ination reaction must be conducted under an inactive gas atmo-
sphere with a large excess of the base and the phosphonium salt.
When less than 3 M equiv of the reagents was used, a considerable
amount of unreacted 4 was recovered (Table 1). Preliminarily, side
reactions were shown to occur when the reaction was conducted at
room temperature or the base was equimolar to the phosphonium
salt. When n-BuLi was replaced by LiHMDS or NaHMDS, the iso-
lated yields were 57% and 41%, respectively. The higher yields in
the presence of the lithium cation might result from the coordina-
tion of the carbonyl oxygen to the lithium cation, enhancing the
reactivity of the enol-ester toward the nucleophilic attack of the
phosphonium ylide. These data support a plausible mechanism of
the reaction as shown in Scheme 2.
2. Results and discussion
Acetonation of (+)-proto-quercitol (2) with 2,2-dimethoxypro-
pane in the presence of ( )-10-camphorsulfonic acid in acetone,
followed by oxidation with a pyridine–sulfur trioxide complex
and triethylamine, afforded crystalline ketone 37b in a 53% yield
(Scheme 1). Next, the trans-isopropylidene group of 3 was selec-
tively removed with a catalytic amount of pyridinium-p-toluene-
sulfonate in methanol to give a dihydroxyketone that was, after
treatment with benzoyl chloride in pyridine, converted into the
single enol-benzoate 4 in 60% yield. The 1H NMR spectrum of 4
showed a doublet (J = 2.6 Hz) at d 5.95, attributable to the alkene
proton of the assigned structure. It is noteworthy that the enol-
benzoate 4 could be readily prepared from 2 on a ten gram scale
without column purification. A similar acylation with acetic anhy-
dride produced a syrupy mixture of products, most likely com-
posed of unsaturated ketones and enol-acetates. Direct treatment
of 4 under Wittig reaction conditions with an excess of methyltri-
phenylphosphonium bromide (6 M equiv)/n-BuLi (4 M equiv) in
THF smoothly resulted in the desired conjugated alkadiene 5 in
66% yield after purification on a silica gel column. In the 1H NMR
spectrum of 5, two new singlet protons at d 5.42 and 5.45 were as-
signed as the exo-olefin protons. The two coupled signals at d 5.78
The alkadiene 5 was treated with a slight excess of bromine in
carbon tetrachloride to give a 68% yield of an epimeric mixture of
the 1,4-addition products 6
tra of 6 and 6b revealed a doublet at d 6.20 (J = 6.0 Hz) and a dou-
blet at d 6.17 (J = 2.7 Hz), which could be assigned as the protons
attached to the carbon atom bonded to - and b-bromine atoms,
respectively. The ratio of 6 and 6b was estimated to be approxi-
a
and 6b (Scheme 3). The 1H NMR spec-
a
a
a
mately 1:1 based on the integrals of the CHBr signals. Because sep-
aration of the epimers was rather difficult, the intact mixture was
used directly in the next reaction. The primary bromo group was
easily replaced with a benzoate anion to give the monobrominated
O
OH
O
a
O
OH
O
HO
O
compounds. Thus, a selective nucleophilic substitution of 6
a and
HO
OH
6b was conducted with sodium benzoate (1.2 M equiv) in DMF at
room temperature affording, after separation on a silica gel column
2
3
(95:5 hexane/ethyl acetate), the monobromo compounds 7
a (48%)
and 7b (27%). The 1H NMR signal from 7
a
at d 5.15, which appeared
b
c
as a double of doublets with J = 3.9 and 8.5 Hz, was assigned as H-
2. H-2 from 7b appeared as a triplet at d 5.78 with J = 7.8 Hz. The
configuration was further confirmed by the NOE correlation ob-
served in the NOESY spectra of 7
data). An NOE correlation was observed between H-1 and H-2 from
, whereas its correlation was not shown from 7b. These results
suggest the stereo configuration of the bromine atom at C-1 posi-
tion in 7 and 7b. Zemplén deacylation of 7 and 7b with sodium
methoxide (using 0.56 and 1.1 M equiv, respectively) in methanol
gave diol 8 (65%) and epoxide 9 (44%), respectively. Under these
conditions, the expected b-bromodiol could not be obtained, but
instead, -bromodiol 8 and epoxide 9 were isolated. First, the
a and 7b (see Supplementary
OBz
O
O
7a
O
BzO
O
OBz
BzO
a
a
4
5
a
Scheme 1. Synthesis of an alkadiene benzoate
5 from (+)-proto-quercitol (2).
a
a
Reagents and conditions: (a) 2,2-dimethoxypropane (10 M equiv), ( )-10-camphor-
sulfonic acid (0.2 M equiv), acetone, rt, 19 h; pyridine–sulfur trioxide complex
(3 M equiv), Et3N (2 M equiv), DMSO, 0 °C to rt, 4.5 h, 53% based on 2; (b)
pyridinium-p-toluenesulfonate (0.2 M equiv), MeOH, 4 °C, 23 h; benzoyl chloride
(8 M equiv), pyridine, 0 °C to rt, 21 h, 60% based on 3; (c) methyltriphenylphos-
phonium bromide (6 M equiv), n-BuLi (4 M equiv), THF, ꢀ78 °C to 4 °C, 21 h, 66%.
b-bromodiol was formed, followed by a possible neighboring-
group participation reaction where the trans-hydroxyl moiety at
the adjacent carbon atom displaced the bromine to give 9. In stud-
ies on amination of the corresponding diacetyl derivatives, the b-

10
S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
Ph
O
H2C- P+Ph
Ph
Ph
O-
O
O
O
- PhCOCH2P+Ph3
O
BzO
OBz
O
BzO
OBz
4
- BzO-
+H2C-P+Ph3
O
O
O
O
O
BzO
BzO
5
Scheme 2. A plausible mechanism for the one-pot elimination of benzoate and the exo-olefination reaction.
improved the yields (75%?91%) of bromo compounds 7
(1.7:1). The change in the :b ratio is likely attributable to epimer-
ization at C-1, which occurs via nucleophilic attack of the bromide
ion, reaching an equilibrium between 7 and 7b. Subsequent O-
debenzoylation of the mixture afforded, after separation, 8
(47%) and 9 (26%). The above mixture of 8 and 9 was similarly
treated with n-octylamine (3.5 M equiv), which afforded, after
the usual processing and purification, the free amine 1a at a 47%
overall yield. Thus, the synthesis of 1a could be readily conducted
from 5 at an approximately 30% yield without separation of the
isomeric products. The practical combined yield from 2 was 6%
over nine steps. Moreover, the free amine 1a could be converted
into the hydrochloride salt 1a0 by treatment with a 1 M HCl aque-
ous solution (98%). This hydrochloride salt was used in the follow-
ing biochemical assay.
The versatility of intermediate alkadiene 5 gave us an opportu-
nity to develop some derivatives of NOEV. 6-Deoxy NOEV (12) is a
particularly important derivative because previous research re-
vealed that the 6-deoxy galactopyranosylamine (fucopyranosyl-
amine)-type carbasugars tended to show stronger galactosidase
inhibitory activities when compared to the intact 6-hydroxy par-
ent.9b Therefore, we synthesized 6-deoxy NOEV, which was ex-
pected to be a potent b-galactosidase inhibitor. The mixture of
a and 7b
Table 1
Optimization of the base in the preparation of 5 under Wittig reaction conditions
a
Base
Yieldc
a
n-BuLia
65%
a
n-BuLib
22% (39% recovered)
57%
41%
LiHMDSa
NaHMDSa
a
a
b
c
Ph3PCH3Br (6 equiv), base (4 equiv).
Ph3PCH3Br (3 equiv), base (2 equiv).
Isolated yield.
bromine was displaced by the nucleophilic amine to give the b-
amino compound through the neighboring participation of the
acetoxyl group.4c,d Therefore, in this case, the reaction course was
controlled by the nucleophilicity and the stereochemical prefer-
ence of the neighboring hydroxyl group under the basic conditions.
Incorporation of an alkylamino functionality at C-1 of
a-bromo-
diol 8 was accomplished by direct nucleophilic substitution with
a
n-octylamine (2.5 M equiv) in acetonitrile in the presence of potas-
sium carbonate (1.5 M equiv) at approximately 60 °C. The coupling
products were treated with aqueous acetic acid and the resulting
aminoalcohol was purified by a silica gel column with a solvent
system of acetic acid/chloroform/methanol followed by a Doulite
C20 (H+) resin column with a gradient elution of 80% aqueous
methanol to methanol/conc. aqueous ammonia (4:1). This afforded
free NOEV (1a) at a 52% yield. This compound was unambiguously
identified by comparing its spectral data, specific rotation, and bio-
logical activity, including its inhibitory activity toward b-galactosi-
dase and chemical chaperone activity.4b Likewise, epoxide 9
underwent regioselective cleavage with n-octylamine (2.5 M e-
quiv) to afford, after a similar purification process, the free base
1a (48%). Thus, both isomeric intermediates formed by bromina-
tion could be successfully transformed into the target compound.
6a
and 6b readily prepared from alkadiene 5 was reduced with so-
dium borohydride (2.2 M equiv) in HMPA/H2O (4:1) at room tem-
perature (Scheme 4). Because the primary bromo groups in 6 and
a
6b had a higher reactivity than the secondary bromo groups in
selective acylation reactions, selective reduction of the primary
bromo groups under appropriate conditions successfully gave
10
umn.9a The following de-acylation of 10
(0.23 M equiv) in methanol yielded alcohol 11 (61%, with 11%
recovery of 10 ). SN2 substitution with n-octylamine (3.5 M equiv)
a
(68%) and 10b (23%) after purification over a silica gel col-
a
with sodium methoxide
a
in acetonitrile followed by de-acetalization under acidic conditions
with hydrochloric acid and THF in a one pot reaction afforded the
hydrochloride of 6-deoxy NOEV (12, 90%). Similarly, b-bromo com-
pound 10b is thought to be selectively transformed into 12.
The above studies suggested that compounds 6
a and 6b could
be directly converted into the desired NOEV through an identical
process without separation of each set of isomers (as we briefly
introduced in4d). Optimization of the above process was attempted
to improve the potential of this practical synthesis of 1a. Specifi-
cally, the yield of the bromine addition to alkadiene 5 was in-
creased to 85% in the presence of two equivalents of sodium
hydrogen carbonate as a scavenger for the hydrobromic acid
formed during the reaction. Increasing the reaction time of the
3. Biochemical assay
Hydrochlorides 1a0 and 12 were assayed for inhibitory activity
against a commercially available b-galactosidase (bovine liver, EC
3.2.1.23). The IC50 value of 12 was 0.20 lM, which indicated that
selective substitution of 6a and 6b (1:1) with the benzoate anion

S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
11
O
a
Br
Br
5
O
BzO
6 ,
α β
b
O
O
OBz
OBz
O
BzO
O
BzO
Br
Br
7α
7β
c
d
O
O
OH
OH
O
O
HO
O
Br
9
8α
e
f
HO
HO
HO
HO
g
OH
OH
H
N+
NH(CH2)7CH3
(CH2)7CH3
Cl-
HO
HO
H
1a
1a'
Scheme 3. Synthesis of NOEV (1a) and its hydrochloride salt (1a0) from an alkadiene (5). Reagents and conditions: (a) bromine (1.2 M equiv), NaHCO3 (1.1 M equiv), CCl4, rt,
0.5 h, 68%; (b) anhydrous sodium benzoate (1.2 M equiv), DMF, rt, 22 h, 75% [7 (48%) and 7b (27%)]; (c) sodium methoxide (0.56 M equiv), MeOH, rt, 2.5 h, 65%; (d) sodium
a
methoxide (1.1 M equiv), MeOH, rt, 2 h, 44%; (e) n-octylamine (2.5 M equiv), K2CO3 (1.5 M equiv), MeCN, 60–65 °C, 22 h; 80% aqueous acetic acid, 80 °C, 4 h, 52%; (f) n-
octylamine (2.5 M equiv), MeCN, 60–70 °C, 22 h; 80% aqueous acetic acid, 80 °C, 4 h, 48%; (g) 1 M HCl (aq), 98%.
12 was approximately ten times more potent than NOEV, which
has an IC50 of 2.6
M10 (Supplementary data Graph 1). This sug-
compound 8a and epoxide 9 were isolated in this study. They may
l
be applied for the synthesis of side-chain-modified derivatives of
1a, for example, N-arylated, azidated, and O- or S-substituted com-
pounds. Furthermore, the other intermediates and the starting
material, (+)-proto-quercitol, may possess great potential for the
preparation of glycosidase inhibitors11 and molecular chaperones,
such as conduritols, conduritol epoxides, aminocyclitols, and con-
duramines. The compounds reported herein should inspire the
synthesis of novel glycosidase inhibitors and pharmacological
chaperones.
gests that removal of the 6-hydroxy group in the 4-epi-b-valien-
amine-type inhibitor can increase the inhibitory activity toward
b-galactosidase. This could be interpreted in the context of the
interactions between the hydrophobic residues in the active site
of b-galactosidase and the C-6 position of the inhibitor. Further
studies examining its chaperone activity against human lysosomal
b-galactosidase could be interesting. The present paper contributes
to rational design concerning the development of both novel galac-
tosidase inhibitors and chaperone therapy drugs.
Here, we have described convenient syntheses of the N-alkyl-
ated unsaturated carbagalactosylamine 1a and its 6-deoxy deriva-
tive, 12. The alkadiene intermediate 5 is expected to serve as a
versatile intermediate for the development of interesting deriva-
tives such as 12. It was also revealed that removal of the hydroxyl
group at the C-6 position of 1a enhanced the inhibitory activity
4. Experimental methods
4.1. General methods
Optical rotations were measured with a HORIBA SEPA-200 high
sensitivity polarimeter, and
[
a]
values are given in
D
10ꢀ1 deg cm2 gꢀ1. Melting points were measured on a Yamato
against bovine liver b-galactosidase. In addition, both the a-bromo

12
S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
4.1.1. 2,3:4,5-Di-O-Isopropylidene derivative of (2R,3R,4S,5R)-
2,3,4,5-tetrahydroxy-cyclohexanone (3)
O
Br
Br
O
A mixture of (+)-proto-quercitol (2) (5.00 g, 30.5 mmol), 2,2-
dimethoxypropane (36.8 mL, 301 mmol), and ( )-10-camphorsul-
fonic acid (1.42 g, 6.09 mmol) in acetone (350 mL) was stirred for
19 h at rt. Saturated aqueous NaHCO3 (30 mL) was added to the
mixture, and stirring was continued for 10 min. The solution was
filtered, and the filtrate was concentrated. The residue was ex-
tracted with EtOAc twice, and the extracts were concentrated.
The residual product was dissolved in DMSO (30 mL) and Et3N
(12.7 mL, 91.5 mmol) and pyridine–sulfur trioxide complex
(9.71 g, 61.0 mmol) was added at 0 °C. The mixture was stirred
for 4.5 h at rt and then the reaction was quenched by the addition
of saturated aqueous NaHCO3 (30 mL). The solution was extracted
with diethyl ether (150 mL ꢁ 2), and the extracts were washed with
water and brine, dried, and concentrated. Crystallization of the res-
idue from ethanol gave 3 (3.94 g, 53% for 2 steps) as white crystals:
BzO
6 ,
α β
a
O
O
O
O
Br
BzO
BzO
mp 153–155 °C; ½a D25
ꢂ
ꢀ80° (c 1.0, CHCl3); RF = 0.47 (1:1 hexane/
Br
EtOAc); 1H NMR (400 MHz, CDCl3): d 1.35, 1.43, 1.45, 1.47 (4s, each
3H, 2 CMe2), 2.45 (dd, 1H, J5,6eq = 11.0, J6ax,6eq = 18.8 Hz, H-6 equiv),
2.96 (dd, 1H, J5,6ax = 7.6, J6ax,6eq = 18.5 Hz, H-6ax), 3.53 (dd, 1H,
J3,4 = 7.6, J4,5 = 10.3 Hz, H-4), 4.09 (td, 1H, J5,6ax = 7.0,
J4,5 = J5,6eq = 10.6 Hz, H-5), 4.46 (d, 1H, J2,3 = 8.7 Hz, H-2). 4.61 (dd,
1H, J3,4 = 7.3, J2,3 = 8.7 Hz, H-3); 13C NMR (100 MHz, CDCl3): d
24.69, 26.62, 26.95, 27.09, 41.06, 70.60, 75.10, 78.65, 82.18,
112.24, 113.51, 203.60; HR-ESI-MS: 265.1046 (C12H18O5Na+,
[M+Na]+; calcd 265.1046).
10
10
β
α
b
O
O
HO
Br
4.1.2. 3,4-O-Isopropylidene derivative of (1R,2S,3R,4R)-1,2,5-
tribenzoyloxycyclohex-5-ene-3,4-diol (4)
11
Pyridinium-p-toluenesulfonate (2.07 g, 8.25 mmol) was added
portionwise to an ice-cold solution of compound
3 (10.0 g,
c
41.3 mmol) in methanol (400 mL). The mixture was kept at 4 °C
for 23 h and then neutralized with Et3N. The solution was concen-
trated and co-evaporated with acetone. The residue was dissolved
in pyridine (400 mL) and cooled in an ice bath, and benzoyl chlo-
ride (38.4 mL, 330 mmol) was added. The mixture was stirred at
rt for 21 h. After the addition of cold saturated aqueous NaHCO3,
the mixture was stirred for another 0.5 h at rt. The precipitates
were collected by filtration, washed with water, and reprecipitated
from ethanol/water. The amorphous product was dried by co-
evaporation with ethanol/toluene to give 4 (12.8 g, 60% for 2 steps)
HO
HO
H
N+
(CH2)7CH3
HO
Cl-
H
12
Scheme 4. Synthesis of 6-deoxy NOEV (12) from the bromo compounds 6
Reagents and conditions: (a) NaBH4 (2.2 M equiv), HMPA/H2O (4:1), rt, 3 h, 91% (a:
68%, b: 23%); (b) sodium methoxide (0.23 mol equiv), MeOH, 4 °C, 19 h and rt and
2 h, 61% (recover 10%); (c) n-octylamine (3.5 M equiv), MeCN, 60 °C, 22 h; 2 M HCl
(aq)/THF (1:1), rt, 2.5 h, 90%.
a
and 6b.
as a white powder: ½a D25
ꢀ43° (c 1.0, CHCl3); RF = 0.35 (4:1 hexane/
ꢂ
EtOAc); 1H NMR (400 MHz, CDCl3): d 1.38 and 1.62 (2s, each 3H,
CMe2), 4.63 (dd, 1H, J3,4 = 6.0, J2,3 = 7.8 Hz, H-3), 5.01 (broad d,
1H, J3,4 = 6.0 Hz, H-4), 5.83 (t, 1H, J1,2 = J2,3 = 7.8 Hz, H-2), 5.89
(broad dd, 1H, J1,6 = 2.3, J1,2 = 7.3 Hz, H-1), 5.95 (broad d, 1H,
J1,6 = 2.3 Hz, H-6), 7.36–7.42 (m, 4H, Ph), 7.45–7.52 (m, 4H, Ph),
7.59–7.63 (m, 1H, Ph), 7.97–8.04 (m, 4H, Ph), 8.10–8.12 (m, 2H,
Ph); 13C NMR (100 MHz, CDCl3): d 26.40, 27.87, 69.43, 71.31,
72.23, 75.02, 112.21, 117.01, 128.35, 128.38, 128.57, 128.85,
129.28, 129.46, 129.84, 129.86, 130.25, 133.22, 133.29, 133.84,
146.26, 164.42, 165.53, 165.79; HR-ESI-MS: 537.1522
(C30H26O8Na+, [M+Na]+; calcd 537.1520).
Melting Point Apparatus Model MP-21 and are uncorrected. 1H
NMR spectra were recorded in solutions of CDCl3 and CD3OD with
a JEOL JNM-ECS 400 (400 MHz) instrument; d(H) values are re-
ported in parts per million relative to the solvent’s residual 1H sig-
nal CDCl3, d(H) 7.24; CD3OD, d(H) 3.30. 13C NMR spectra (100 MHz)
were recorded on the same instrument as for 1H spectra; d(C) is re-
ported in ppm relative to the solvent’s C signal CDCl3, d(C) 77.0;
CD3OD, d(H) 49.0, unless otherwise noted. High-resolution electron
spray ionization mass spectra (HR-ESI-MS) were obtained on a LTQ
Orbitrap mass spectrometer (Thermo Fisher Scientific, Bremen,
Germany). TLC was performed using silica gel 60 F-254 (Merck,
Drmstadt, Germany). The silica gel used for chromatography was
Wakogel C-300 (Wako Junyaku Kogyo Co., Osaka, Japan, 200–
300 mesh). Organic solutions were dried over anhydrous Na2SO4
and concentrated with a rotary evaporator under reduced pressure
at a temperature less than 60 °C. In Sections 4.1.4. to 4.1.11., carba-
sugar nomenclature following the IUPAC–IUBMB Nomenclature of
Carbohydrates (Recommendation 1996: Carbohydr. Res., 1997, 297,
1–92) was adopted for the sake of general understanding.
4.1.3. 2,3-O-Isopropylidene derivative of (1R,2S,3S)-1-
benzoyloxy-4-methylenecyclohex-5-ene-2,3-diol (5)
n-BuLi (1.65 M solution in hexane, 14.2 mL, 23.4 mmol) was
added to a solution of methyltriphenylphosphonium bromide
(12.5 g, 35.0 mmol) in dry THF (12 mL) under a nitrogen atmo-
sphere cooled with an acetone/dry ice bath (ꢀ78 °C). The mixture
was then stirred for 1 h in an ice bath. The mixture was cooled
again in an acetone/dry ice bath, and a solution of compound 4
(3.00 g, 5.83 mmol) in dry THF (46 mL) was slowly added via syr-
inge. After stirring at 4 °C for 21 h, the reaction solution was loaded
onto a silica gel column, and the column was eluted with 4:1 hex-

S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
13
ane/EtOAc. The eluate was passed through a Celite bed with EtOAc
and concentrated. The residue was purified on a silica gel column
(95:5 hexane/EtOAc) to give 5 (1.11 g, 66%) as a colorless syrup:
4.74 (dd, 1H, J3,4 = 6.4, J2,3 = 8.7 Hz, H-3), 4.83 (d, 1H, J3,4 = 6.4 Hz,
H-4), 4.91–5.06 (3H, H-1, CH2), 5.15 (dd, 1H, J1,2 = 3.9,
J2,3 = 8.5 Hz, H-2), 6.22 (d, 1H, J1,5a = 6.0 Hz, H-5a), 7.42–7.48 (m,
4H, Ph), 7.55–7.60 (m, 2H, Ph), 8.07–8.13 (m, 4H, Ph); 13C NMR
(100 MHz, CDCl3): d 25.67, 27.58, 44.61, 64.24, 71.67, 72.38,
73.82, 110.28, 125.66, 128.41, 128.47, 129.47, 129.69, 129.77,
130.01, 133.25, 133.39, 134.48, 165.85, 165.93; HR-ESI-MS:
509.0570 (C24H23O6BrNa+, [M+Na]+; calcd 509.0570).
½
a 2D5 +220° (c 1.0, CHCl3); RF = 0.45 (4:1 hexane/EtOAc); 1H NMR
ꢂ
(400 MHz, CDCl3): d 1.42 and 1.50 (2s, each 3H, CMe2), 4.37 (t,
1H, J1,2 = J2,3 = 5.3 Hz, H-2), 4.76 (d, 1H, J2,3 = 5.5 Hz, H-3), 5.42,
5.45 (2s, each 1H, CH2), 5.66–5.68 (m, 1H, H-1), 5.78 (broad d,
1H, J5,6 = 10.1 Hz, H-5), 6.32 (dd, 1H, J1,6 = 1.8, J5,6 = 10.1 Hz, H-6),
7.40–7.43 (m, 2H, Ph), 7.52–7.55 (m, 1H, Ph), 8.03–8.05 (m, 2H,
Ph); 13C NMR (100 MHz, CDCl3): d 26.22, 27.89, 71.06, 73.30,
76.43, 109.25, 120.54, 125.23, 128.29, 129.71, 129.88, 130.15,
133.08, 138.31, 165.84; HR-ESI-MS: 309.1100 (C17H18O4Na+,
[M+Na]+; calcd 309.1097).
For 7b: ½a 2D5
ꢂ
+16o (c 1.0, CHCl3); RF = 0.24 (4:1 hexane/EtOAc);
1H NMR (400 MHz, CDCl3): d 1.37 and 1.56 (2s, each 3H, CMe2),
4.35 (dd, 1H, J3,4 = 6.0, J2,3 = 7.8 Hz, H-3), 4.66–4.68 (m, 1H, H-1),
4.72 (d, 1H, J3,4 = 5.5 Hz, H-4), 4.99 (br s, 2H, CH2), 5.68 (t, 1H,
J1,2 = J2,3 = 7.8 Hz, H-2), 6.16 (br s, 1H, H-5a), 7.40–7.47 (m, 4H,
Ph), 7.53–7.60 (m, 2H, Ph), 8.03–8.07 (m, 4H, Ph); 13C NMR
(100 MHz, CDCl3): d 26.28, 27.70, 44.06, 64.37, 71.97, 74.10,
75.22, 111.50, 127.94, 128.37, 128.50, 129.55, 129.68, 129.73,
129.89, 130.02, 132.85, 133.28, 165.23, 165.98; HR-ESI-MS:
509.0559 (C24H23O6BrNa+, [M+Na]+; calcd 509.0570).
4.1.3.1. Procedure for comparative studies of Wittig reaction
conditions.
The corresponding base (0.780 or 1.56 mmol)
was added to a solution of methyltriphenylphosphonium bromide
(1.17 or 2.34 mmol) in dry THF (1 mL) under a nitrogen atmo-
sphere in an acetone/dry ice bath. The mixture was then stirred
for 1 h in an ice bath. The mixture was cooled again in an ace-
tone/dry ice bath, and a solution of 4 (200 mg, 0.390 mmol) in
dry THF (3 mL) was slowly added via syringe. After stirring over-
night at 4 °C for 22 h, the reaction solution was charged onto a
short pad of silica gel and Celite, and the pad was eluted with
1:1 hexane/EtOAc. The filtrate was concentrated and the residue
was purified on a silica gel column (95:5 hexane/EtOAc) to give 5.
4.1.6. 3,4-O-Isopropylidene-5a-carba-b-
enopyranosyl bromide (8
A 1 M sodium methoxide/methanol (498
tion and methanol rinse (200 L) were added to a solution of 7
L-arabino-hex-5(5a)-
a)
lL, 0.50 mmol) solu-
l
a
(692 mg, 1.40 mmol) in dry methanol (14 mL). After stirring at rt
for 2 h, another portion of 1 M sodium methoxide/methanol
(280 lL, 0.28 mmol) was added to the mixture and it was stirred
for an additional 0.5 h. The solution was neutralized with Duolite
C20 (H+) resin, filtered, and evaporated. The residual product was
chromatographed on a silica gel column (4:1?2:1 hexane/EtOAc)
4.1.4. 2-O-Benzoyl-3,4-O-isopropylidene-6-bromo-6-deoxy-5a-
carba-b-L-arabino-hex-5(5a)-enopyranosyl bromide (6a) and 2-
O-Benzoyl-3,4-O-isopropylidene-6-bromo-6-deoxy-5a-carba-
a-
to give the bromodiol 8
a
(254 mg, 65%) as a colorless solid: ½a D25
ꢂ
L-arabino-hex-5(5a)-enopyranosyl bromide (6b)
+350o (c 1.0, CHCl3); RF = 0.20 (1:1 hexane/EtOAc); 1H NMR
(400 MHz, CDCl3): d 1.37 and 1.45 (2s, each 3H, CMe2), 2.20 (broad
s, 1H, OH), 2.64 (broad d, 1H, OH), 3.68–3.70 (m, 1H, H-2), 4.19–
4.35 (3H), 4.69–4.74 (2H), 6.07 (d, 1H, J1,5a = 5.5 Hz, H-5a), assigned
by H-H COSY; 13C NMR (100 MHz, CDCl3): d 25.56, 27.70, 50.41,
63.77, 70.19, 72.73, 109.87, 124.10, 138.57; HR-ESI-MS: 301.0054
(C10H15BrO4Na+, [M+Na]+; calcd 301.0046).
Bromine (280
lL, 5.46 mmol) was added dropwise to a stirred
mixture of compound
5
(1.36 g, 4.75 mmol) and NaHCO3
(748 mg, 5.23 mmol) in CCl4 (48 mL). The resulting mixture was
stirred at rt for 0.5 h. After dilution with CHCl3 (100 mL), the reac-
tion mixture was washed with saturated aqueous NaHCO3 (50 mL)
and water (50 mL), dried, and evaporated. The residue was chro-
matographed on a silica gel column (95:5?9:1 hexane/EtOAc) to
give a mixture of the isomeric dibromo compounds 6
(1.45 g, 68%) as a colorless syrup. The ratio of 6 to 6b was esti-
mated to be approximately 1:1 by 1H NMR analysis.
For
and 6b: RF = 0.63 (95:5 toluene/EtOAc); 1H NMR
(400 MHz, CDCl3): d 1.39, 1.41, 1.45 and 1.52 (4s, each 3H, CMe2(6
and CMe2(6b)), 4.02 and 4.04 (2s, each 1H), 4.21 and 4.24 (2s, each
1H), 4.37 (dd, 1H, J = 6.0, 7.8 Hz), 4.61–4.64 (m, 1H), 4.71 (dd, 1H,
J = 6.6, 8.5 Hz), 4.88 (t, 1H, J = 4.6 Hz), 4.93 (d, 1H, J = 5.5 Hz), 5.02
(d, 1H, J = 6.4 Hz), 5.10 (dd, 1H, J = 3.9, 8.5 Hz), 5.64 (t, 1H,
J = 7.3 Hz), 6.17 (d, 1H, J1,5a (6b) = 2.7 Hz, H(6b)-5a), 6.20 (d, 1H,
a
and 6b
4.1.7. 1,2-Epoxy-3,4-O-isopropylidene-5a-carba-b-L-arabino-
hex-5(5a)-enopyranose (9)
a
A
1 M sodium methoxide/methanol solution (580
lL,
6a
0.58 mmol) and methanol rinse (200
lL) were added to a solution
of 7b (270 mg, 0.554 mmol) in dry methanol (4.4 mL). After stirring
at rt for 2 h, the mixture was neutralized with 0.1 M hydrochloric
acid in methanol and evaporated. The residue was chromato-
graphed on a silica gel column (4:1?2:1 hexane/EtOAc) to give 9
a
)
(48 mg, 44%) as a colorless syrup: ½a D25
ꢂ
ꢀ23o (c 1.0, CHCl3);
RF = 0.41 (1:1 hexane/EtOAc); 1H NMR (400 MHz, CDCl3): d 1.37
(s, 6H, CMe2), 2.20 (broad s, 1H, OH), 3.34 (t, 1H, J1,2 = J1,5a = 3.9 Hz,
H-1), 3.53 (dd, 1H, J2,3 = 1.8, J1,2 = 3.7 Hz, H-2), 4.20 (br s, 2H, CH2),
4.46 (d, 1H, J3,4 = 7.3 Hz, H-4), 4.77 (d, 1H, J3,4 = 6.9 Hz, H-3), 6.01–
6.04 (m, 1H, H-5a), assigned by H–H COSY; 13C NMR (100 MHz,
CDCl3): d 25.73, 27.52, 47.00, 50.08, 63.60, 71.19, 71.38, 110.71,
118.94, 141.85; HR-ESI-MS: 221.0779 (C10H14O4Na+, [M+Na]+;
calcd 221.0784).
J1,5a
) = 6.0 Hz, H(6 )-5a), 7.41–7.46 (m, 4H, Ph), 7.54–7.59 (m,
(6
a
a
2H, Ph), 8.03–8.04 (m, 2H, Ph), 8.10–8.12 (m, 2H, Ph), assigned
by H-H COSY.
4.1.5. 2,6-Di-O-Benzoyl-3,4-O-isopropylidene-5a-carba-b-
arabino-hex-5(5a)-enopyranosyl bromide (7 ) and 2,6-di-O-
-arabino-hex-5(5a)-
L-
a
Benzoyl-3,4-O-isopropylidene-5a-carba-
a-L
enopyranosyl bromide (7b)
A solution of a mixture of 6
a
and 6b (1.41 g, 3.15 mmol) and
4.1.8. N-Octyl-5a-carba-
enopyranosylamine (1a)
From mixture of
(140 mg, 1.01 mmol), n-octylamine (279
tonitrile (3.4 mL) was stirred at 60–65 °C for 22 h. It was cooled
to rt, filtered, and evaporated. The residue was chromatographed
on a silica gel column (97:3 CHCl3/MeOH) and the major fractions
were concentrated. The residue was dissolved in aqueous 80% ace-
tic acid (6.5 mL) and the solution was stirred at 80 °C for 4 h. The
mixture was co-evaporated with toluene and the residue was puri-
a-L-arabino-hex-5(5a)-
anhydrous sodium benzoate (522 mg, 3.62 mmol) in DMF
(32 mL) was stirred at rt for 22 h. After dilution with EtOAc
(300 mL), the solution was washed with water (100 mL ꢁ 2) and
brine, dried, and evaporated. The residue was fractionated on a sil-
ica gel column (95:5 hexane/EtOAc) to give monobromo com-
8a
:
A
8a
(187 mg, 0.670 mmol), K2CO3
L, 1.68 mmol), and ace-
l
pounds 7a (732 mg, 48%) as a white solid and 7b (419 mg, 27%)
as a colorless syrup.
For 7a
: ½a 2D5
ꢂ
+190° (c 1.0, CHCl3); RF = 0.36 (4:1 hexane/EtOAc);
1H NMR (400 MHz, CDCl3): d 1.39 and 1.47 (2s, each 3H, CMe2),

14
S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
fied on a silica gel column (10:86:4?1:6:3 AcOH/CHCl3/MeOH) to
give the acetate salt of 1a. It was chromatographed on a column of
Duolite C20 (H+) resin (80% aqueous methanol?4:1 methanol/
conc. aqueous ammonia) to give 1a (100 mg, 52%) as a white solid:
½
a 2D5 +9.8° (c 1.0, MeOH); RF = 0.41 (1:6:3 AcOH/CHCl3/MeOH); 1H
ꢂ
NMR (400 MHz, CD3OD): d 0.90 (t, 3H, J7 ,8 = 6.9 Hz, H-80), 1.31–
0
0
1.43 (10H, H-30, 40, 50, 60, and 70), 1.68–1.75 (m, 2H, H-20), 3.09 (t,
2H, J1 ,2 = 7.8 Hz, H-10), 3.53 (dd, 1H, J3,4 = 3.9, J2,3 = 9.8 Hz, H-3),
3.72 (dd, 1H, J1,5a = 2.3, J1,2 = 8.2 Hz, H-1), 3.95 (dd, 1H, J1,2 = 8.2,
J2,3 = 9.6 Hz, H-2), 4.11–4.25 (3H, H-4, CH2), 5.75 (d, 1H,
J1,5a = 1.8 Hz, H-5a); 13C NMR (100 MHz, CD3OD): d 14.40, 23.67,
27.46, 27.66, 30.17, 32.88, 45.80, 61.43, 63.26, 67.63, 68.30,
72.96, 116.61, 146.98; HR-ESI-MS: 310.1987 (C15H29O4NNa+,
[M+Na]+; calcd 310.1989).
0
0
½
a 2D5 +3.0o (c 1.0, MeOH); RF = 0.41 (1:6:3 AcOH/CHCl3/MeOH); 1H
ꢂ
NMR (400 MHz, CD3OD): d 0.89 (t, 3H, J7 ,8 = 6.9 Hz, H-80), 1.30–
1.37 (10H, H-30, 40, 50, 60, and 70), 1.48–1.56 (m, 2H, H-20), 2.54–
2.58, 2.72–2.76 (each m, each 1H, H-10), 3.11 (dd, 1H, J1,5a = 1.8,
J1,2 = 8.2 Hz, H-1), 3.44 (dd, 1H, J3,4 = 4.1, J2,3 = 10.1 Hz, H-3), 3.70
(dd, 1H, J1,2 = 8.2, J2,3 = 10.1 Hz, H-2), 4.12 (broad s, 2H, CH2), 4.15
(d, 1H, J3,4 = 4.1 Hz, H-4), 5.71 (d, 1H, J1,5a = 2.3 Hz, H-5a); 13C
NMR (100 MHz, CD3OD): d 14.43, 23.71, 28.42, 30.38, 30.60,
30.88, 32.98, 46.87, 61.78, 63.89, 68.13, 70.78, 73.85, 125.13,
140.73; HR-ESI-MS: 310.1987 (C15H29O4NNa+, [M+Na]+; calcd
310.1989).
0
0
4.1.9. 2-O-Benzoyl-3,4-O-isopropylidene-6-methyl-6-deoxy-5a-
carba-b-
2-O-Benzoyl-3,4-O-isopropylidene-6-methyl-6-deoxy-5a-carba-
-arabino-hex-5(5a)-enopyranosyl bromide (10b)
The isomeric mixture of 6 and 6b (375 mg, 0.841 mmol) was
L-arabino-hex-5(5a)-enopyranosyl bromide (10a) and
a
-L
From 9: A mixture of 9 (48 mg, 0.24 mmol) and n-octylamine
a
(100
70 °C for 22 h. The solution was cooled to rt and evaporated. The
residue was chromatographed on silica gel column (97:3
CHCl3/MeOH), and the fractions containing the major product were
collected and concentrated. The residue was dissolved in aqueous
80% acetic acid (2.5 mL) and the solution was stirred at 80 °C for
4 h. The mixture was processed as described above and the product
was purified on a silica gel column (10:86:4?1:6:3 AcOH/CHCl3/
MeOH) to give the amine as the acetate salt. A similar workup as
above gave 1a (33 mg, 48%).
l
L, 0.606 mmol) in acetonitrile (2.4 mL) was stirred at 60–
dissolved in 5 mL of HMPA/H2O (4:1). Sodium borohydride
(70 mg, 1.85 mmol) was added to the solution portionwise. With
3 mL of HMPA/H2O (4:1), the rinse was added to the reaction solu-
tion. The solution was stirred at rt for 3 h. After dilution with H2O
(20 mL), the solution was extracted with diethyl ether (60 mL ꢁ 3).
The combined organic phases were dried and evaporated. The res-
idue was purified on a silica gel column (97:3?95:5 hexane/
a
EtOAc) to give 10
(71 mg, 23%) as a white powder.
For 10 [(purified by silica gel column chromatography (hex-
ane/toluene = 1:2) for analysis]:
+340o (c 1.0, CHCl3);
a (211 mg, 68%) as a colorless syrup and 10b
a
From 5 (without separation of the bromo compounds): Bro-
½ ꢂ
a 2D5
mine (407
lL, 7.93 mmol) was slowly added dropwise to a stirred
RF = 0.54 (4:1 hexane/EtOAc); 1H NMR (400 MHz, CDCl3): d 1.39
and 1.47 (2s, each 3H, CMe2), 1.94 (s, 3H, Me), 4.61 (d, 1H,
J3,4 = 6.4 Hz, H-4), 4.69 (dd, 1H, J3,4 = 6.4, J2,3 = 8.7 Hz, H-3), 4.86
(dd, 1H, J1,2 = 3.9, J1,5a = 5.7 Hz, H-1), 5.03 (dd, 1H, J1,2 = 3.9,
J2,3 = 8.9 Hz, H-2), 5.85 (br d, 1H, J1,5a = 6.4 Hz, H-5a), 7.42–7.45
(m, 2H, Ph), 7.54–7.58 (m, 1H, Ph), 8.11–8.13 (m, 2H, Ph); 13C
NMR (100 MHz, CDCl3): d 20.53, 25.56, 27.58, 46.34, 71.89, 73.83,
75.57, 109.58, 124.24, 128.33, 129.60, 129.96, 133.24, 136.40,
166.00; HR-ESI-MS: 389.0352 (C17H19O4BrNa+, [M+Na]+; calcd
389.0359).
mixture of 5 (2.06 g, 7.21 mmol) and NaHCO3 (1.21 g, 14.4 mmol)
in CCl4 (70 mL) at rt. The solution was stirred for 20 min, diluted
with CHCl3 (140 mL), washed with saturated aqueous NaHCO3
(70 mL) and water (70 mL), dried, and evaporated. The residue
was chromatographed on a silica gel column (95:5?9:1 hexane/
EtOAc) to give an isomeric mixture of 6
a
a
and 6b (2.74 g, 85%,
/b = ca. 1:1 as determined by 1H NMR analysis). A solution of
the mixture of 6a and 6b (1.15 g, 2.57 mmol) and anhydrous so-
dium benzoate (425 mg, 2.95 mmol) in DMF (25 mL) was stirred
at rt for 47 h. The reaction mixture was diluted with EtOAc
(300 mL), washed twice with both water and brine, dried, and
evaporated. The residue was fractionated over a silica gel column
For 10b: ½a 2D5
ꢀ35° (c 1.0, CHCl3); RF = 0.42 (4:1 hexane/
ꢂ
EtOAc); 1H NMR (400 MHz, CDCl3): d 1.37 and 1.55 (2s, each
3H, CMe2), 1.93 (s, 3H, Me), 4.27 (dd, 1H, J3,4 = 5.5, J2,3 = 8.2 Hz,
H-3), 4.47 (d, 1H, J3,4 = 5.5 Hz, H-4), 4.62 (br d, 1H, J1,2 = 7.8 Hz,
H-1), 5.62 (t, 1H, J1,2 = J,2,3 = 8.0 Hz, H-2), 5.79 (br s, 1H, H-5a),
7.41–7.45 (m, 2H, Ph), 7.53–7.57 (m, 1H, Ph), 8.04–8.06 (m, 2H,
Ph); 13C NMR (100 MHz, CDCl3): d 20.39, 26.31, 27.77, 45.81,
74.68, 75.38, 75.52, 110.96, 126.07, 128.34, 129.88, 133.15,
134.04, 165.35; HR-ESI-MS: 389.0365 (C17H19O4BrNa+, [M+Na]+;
calcd 389.0359).
(95:5?9:1 hexane/EtOAc) to give 7
(419 mg, 34%). A 0.5 M sodium methoxide/methanol solution
(4.3 mL, 2.2 mmol) was added to mixture of and 7b
a (693 mg, 57%) and 7b
a
7a
(1.01 g, 2.14 mmol) in dry methanol (15 mL). After the mixture
was stirred at rt for 2 h, the solution was carefully neutralized
with 0.1 M hydrochloric acid in methanol and evaporated. The
products were chromatographed on
(4:1?2:1?1:1 hexane/EtOAc) to give 8 (278 mg, 47%) and 9
(110 mg, 26%). Compounds (278 mg, 0.996 mmol) and
(110 mg, 0.555 mmol) were dissolved in acetonitrile (16 mL),
and to this mixture, n-octylamine (899 L, 5.43 mmol) was added.
a
silica gel column
8
9
4.1.10. 3,4-O-Isopropylidene-6-methyl-6-deoxy-5a-carba-b-
L-
arabino-hex-5(5a)-enopyranosyl bromide (11)
l
A 0.5 M sodium methoxide/methanol solution (68
lL, 34 lmol)
After stirring at 60–70 °C for 16 h, the solution was cooled to rt
and evaporated. The product was dissolved in aqueous 80% acetic
acid (16 mL) and stirred at 80 °C for 4 h. The mixture was co-
evaporated with toluene and the residual product was purified
on a silica gel column (10:86:4?1:6:3 AcOH/CHCl3/MeOH) to
give the amine as the acetate salt, which was further chromato-
graphed on a column of Duolite C20 (H+) resin (80% aqueous
methanol?4:1 methanol/conc. aqueous ammonia) to give 1a
(208 mg, 47%).
was added to a solution of 10 (55 mg, 0.15 mmol) in dry metha-
a
nol (1.4 mL) at 4 °C. After stirring at 4 °C for 19 h and at rt for 2 h,
the reaction was carefully quenched with a 0.1 M HCl solution in
methanol. The solution was evaporated, and the residue was chro-
matographed on a silica gel column (9:1?4:1 hexane/EtOAc) to
give 11 (24 mg, 61%) as a colorless syrup with recovery of 6 mg
of 10
a
(10%); ½a 2D5
ꢂ
+100° (c 1.0, CHCl3); RF = 0.20 (4:1 hexane/
EtOAc); 1H NMR (400 MHz, CDCl3): d 1.38 and 1.46 (2s, each 3H,
CMe2), 1.89 (s, 3H, Me), 2.31 (broad s, 1H, OH), 3.60 (dd, 1H,
J1,2 = 3.7 Hz, J2,3 = 8.2 Hz, H-2), 4.28 (dd, 1H, J3,4 = 6.6 Hz,
J2,3 = 8.0 Hz, H-3), 4.52 (d, 1H, J3,4 = 6.4 Hz, H-4), 4.67–4.70 (m,
1H, H-1), 5.79 (d, 1H, J1,5a = 5.0 Hz, H-5a); 13C NMR (100 MHz,
CDCl3): d 20.45, 25.51, 27.76, 51.94, 70.15, 75.59, 76.78, 109.34,
124.20, 136.64; HR-ESI-MS: 285.0097 (C10H15O4BrNa+, [M+Na]+;
calcd 285.0097).
4.1.8.1. Amine hydrochloride (1a0).
The free amine 1a
(78 mg, 0.27 mmol) was dissolved in 6 mL of 1 M HCl aqueous
solution. The solution was azeotroped with ethanol several times
and concentrated to dryness. The residue was dried under reduced
pressure to yield 1a0 (86 mg, 98%) as an amorphous white powder:

S. Kuno et al. / Carbohydrate Research 368 (2013) 8–15
15
4.1.11. N-Octyl-6-methyl-6-deoxy-5a-carba-a-L-arabino-hex-
Supplementary data
5(5a)-enopyranosylamine hydrochloric salt (12)
A mixture of 11 (62 mg, 0.236 mmol), n-octylamine (137
lL,
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.carres.2012.
12.010.
0.826 mmol), and acetonitrile (2.3 mL) was added to a sealed tube
and allowed to stand at 60 °C for 22 h. The reaction solution was
cooled to rt and evaporated. The residue was chromatographed
on a silica gel column (99:1?97:3 CHCl3/MeOH). The obtained
product was dissolved in 4 mL of 1 M HCl/THF (1:1) and stirred
at rt for 2.5 h. The reaction solution was concentrated under re-
duced pressure and the residue was re-dissolved in 1.5 mL of
methanol. The solution was passed through a short column of acti-
vated carbon and washed with 40 mL of methanol. The combined
solution was evaporated to yield 12 (65 mg, 90%) as a light yellow
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oil: ½a 2D5
ꢂ
+10o (c 1.0, MeOH); RF = 0.53 (1:6:3 AcOH/CHCl3/MeOH);
1H NMR (400 MHz, CD3OD): d 0.90 (t, 3H, J7 ,8 = 6.9 Hz, H-80), 1.31–
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-galactopy-
D
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Acknowledgements
The authors would like to thank Drs. Ryuichi Sawa and Yoji
Umezawa (Institute of Microbial Chemistry, Tokyo) for the mea-
surement of high-resolution mass spectra, Profs. Katsumi Higaki
and Eiji Nanba for the bioassays (Tottori University, Yonago), Ms.
Yoko Sakata for discussions on the preparative work, and Messrs.
Masanori Yamaguchi and Akihiro Tomoda (Hokko Chemical Indus-
try Co. Ltd, Atsugi) for their kind donation of (+)-proto-quercitol.
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4d
.
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