A practical access to [1-13c]1-deoxy-d-xylulose and its derivatives

Article abstract of DOI:10.1055/s-2003-40860

A practical synthesis of [1-¹³C]1-deoxy-D-xylulose and its triacetate and 5-phosphate derivatives is described. The present scheme is developed based on the consideration of the cost efficiency of ¹³C.

Full text of DOI:10.1055/s-2003-40860

LETTER
1521
A Practical Access to [1-13C]1-Deoxy-D-xylulose and its Derivatives
1
A
P
ractica
l
A
ccessito 3
[
1-
r
C]1-D
e
o
oxy-
D
-xylulo
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se and its
hDerivativesi Okumoto,* Hiroko Katto
Department of Chemistry and Bioscience, Kurashiki University of Science and the Arts, 2640 Nishinoura, Tsurajima, Kurashiki,
712-8505 Japan
Fax +81(86)4401062; E-mail: okmt@chem.kusa.ac.jp
Received 12 May 2003
Although several synthetic routes to DOX and DOXP
have been previously described,2 the prohibitive cost of
the 13C isotope imposes strict restrictions on its use in syn-
thetic approaches. A consideration of the cost efficiency
of 13C isotope usage prompted us to develop a new route
utilizing an appropriate intermediate. The synthetic pro-
cess is outlined in Scheme 1. The synthetic steps follow-
ing the incorporation of the 13C-labeled group must be as
short as possible and a simple operation for isolating the
water-soluble final products is required in the last stage.
Amide 4 is the key precursor that matched our require-
ments. The Weinreb’s amide is known to react readily
with a stoichiometric amount of Grignard reagent to selec-
tively afford the ketone.3 All hydroxyl groups are protect-
ed with a benzyl group to facilitate the quantitative
removal and facile isolation of the resulting sugar deriva-
tives by simple operations, i.e. heterogeneous hydrogena-
tion, filtration and concentration.
Abstract: A practical synthesis of [1-13C]1-deoxy-D-xylulose and
its triacetate and 5-phosphate derivatives is described. The present
scheme is developed based on the consideration of the cost efficien-
cy of 13C.
Key words: isotope, labeled compound, stereoselective synthesis,
carbohydrates, terpenoids, natural products, biosynthesis
Terpenoids are an important class of natural products and
are mainly of plant origin. The potential use of terpenoids
as medicinal agents and aroma ingredients in both the na-
tive and chemically-modified forms is exceedingly high.
For decades it was believed that the isoprene unit, the
smallest constituent of the terpenes, is produced from iso-
prenyl diphosphate (IPP) solely through the mevalonic
acid (MVA) pathway. Recently, an alternative biosynthet-
ic route was discovered, wherein 1-deoxy-D-xylulose
(DOX) 5-phosphate and methyl erythritol (ME) phos-
phate were indispensable for the formation of IPP. The
new pathway has received particular attention, since it
was found to play a major role in isoprenoid biosynthesis
in many bacteria and all plants. Investigations attempting
to delineate the two pathways in plants and plant cell cul-
tures have made use of 13C-labeled compounds such as
glucose and MVA in an effort to trace the fate of the 13C-
labeled metabolites. A 13C NMR analysis of the labeled
metabolites can lead to the successful determination of
biosynthetic pathways, both classical and new. In order to
obtain more detailed and distinct information on the
MVA-independent pathway, there is now a substantial de-
mand for larger quantities of 13C-labeled DOX and ME,
since these substrates are specific to the non-mevalonate
pathway.1
Commercially available mannitol diacetonide (1) was
converted to the alcohol 2 according to a published
procedure4 with slight modification. In the route leading
to the synthesis of DOX 6a and its acetate 6b, the alcohol
2 was protected with BnBr. Transformation of the 1,2-diol
acetonide 3a to the amide 4a was carried out in the usual
manner. Thus, hydrolysis of the acetonide 3a with 5%
HCl in MeOH, and oxidative cleavage of the vicinal diol
followed by treatment of the crude aldehyde with NaClO2
yielded carboxylic acid. Condensation with Weinreb’s
amine proceeded in the presence of DCC and pyridine,
giving rise to intermediate 4a. Incorporation of 13C was
achieved using 13CH3MgI, prepared from commercially
available 13CH3I and Mg, at room temperature to selec-
tively obtain the methyl ketone 5a. Simple hydrogenation
on 10%Pd/C in acetone/H2O at ambient temperature, fol-
lowed by filtration and concentration, lead to the isolation
of the labeled sugar 6a. If necessary, purification by
column chromatography on silica gel with CHCl3/MeOH
can be performed. The stable derivative 6b was afforded
by exposure of 6a to a mixture of acetic anhydride and
pyridine.
Attention was initially focused on the synthesis of 13C-la-
beled DOX, rather than ME, due to the high efficiency of
incorporation of DOX into the culture cell. Thus, we
would like to describe herein a practical and facile synthe-
sis of [1-13C]1-deoxy-D-xylulose (1-13C-DOX), the stable
triacetate derivative, and 1-13C-DOX 5-phosphate (1-13C-
DOXP).
For the synthesis of the phosphate 7, methylation of the
amide 4c was initially performed in a similar way to the
preparation of 5a. The envisioned amide 4c was prepared
by the phosphorylation of the alcohol 2 and the ensuing
conversion of the acetonide moiety to the amide. Howev-
er, the reaction with methyl Grignard reagent prepared
from MeI failed to give the desired methyl ketone in spite
of several attempts under various experimental condi-
Synlett 2003, No. 10, Print: 05 08 2003.
Art Id.1437-2096,E;2003,0,10,1521,1523,ftx,en;U08903ST.pdf.
© Georg Thieme Verlag Stuttgart · New York

1522
H. Okumoto, H. Katto
LETTER
The synthesis of 1-13C-DOX (6a) and its acetate 6b was
achieved in short steps. The last stage, heterogeneous hy-
drogenation, facilitated the isolation of the water-soluble
target molecule. In addition, we can offer a stable deriva-
tive, 1-13C-DOX-triacetate (6b), for use as a tracing mate-
rial in the analysis of biosynthetic pathways.
OH
OBn
O
O
ref.4
O
O
OH
O
O
OH
OBn
1
2
a or b or c
References
O
OBn
OBn
OR
O
d
O
OR
(1) (a) Thiel, R.; Adam, K. P. Phytochemistry 2002, 59, 269.
(b) Putra, S. R.; Lois, L. M.; Campos, N.; Boronat, A.;
Rohmer, M. Tetrahedron Lett. 1998, 39, 23; and references
cited therein.
(2) For the enzymatic synthesis, see: (a) Querol, J.;
Grosdemange-Billiard, C.; Rohmer, M.; Boronat, A.;
Imperial, S. Tetrahedron Lett. 2002, 43, 8265. (b) Hecht,
S.; Kis, K.; Eisenreich, W.; Amslinger, S.;
N
OMe OBn
OBn
4a: R=Bn (70%)
4b: R=PMB (62%)
4c: R=P(O)(OBn)2 (41%)
3a: R=Bn (99%)
3b: R=PMB (84%)
3c: R=P(O)(OBn)2 (99%)
e
Wungsintaweekul, J.; Herz, S.; Rohdich, F.; Bacher, A. J.
Org. Chem. 2001, 66, 3948. (c) Shabat, D.; List, B.; Lerner,
R. A.; Barbas, C. F. III. Tetrahedron Lett. 1999, 40, 1437.
(d) For the chemical synthesis, see: Fechter, M. H.;
Gaisberger, R.; Griengl, H. J. Carbohydr. Chem. 2001, 20,
833. (e) Zhao, S.; Petrus, L.; Serianni, A. S. Org. Lett. 2001,
3, 3819. (f) See also: Hoeffler, J.-F.; Grosdemange-Billiard,
C.; Rohmer, M. Tetrahedron Lett. 2001, 42, 3065.
(g) Blagg, B. S.; Poulter, C. D. J. Org. Chem. 1999, 64,
1508. (h) See further: Jux, A.; Boland, W. Tetrahedron Lett.
1999, 40, 6913. (i) Thiel, R.; Adam, K. P. Tetrahedron Lett.
1999, 40, 5307. (j) Tayler, S. V.; Vu, L. D.; Begley, T. P. J.
Org. Chem. 1998, 63, 2375. (k) Giner, J.-L. Tetrahedron
Lett. 1998, 39, 2479. (l) Piel, J.; Boland, W. Tetrahedron
Lett. 1997, 38, 6387. (m) Zeidler, J. G.; Lichtenthaler, H. K.;
May, H. U.; Lichtenthaler, F. W. Z. Naturforsch., C: Biosci.
1997, 52, 15. (n) Kennedy, I. A.; Hemscheidt, T.; Britten, J.
F.; Spenser, I. D. Can. J. Chem. 1995, 73, 1329.
O
OBn
O
OY
f
OR
OY
13CH3
13CH3
OBn
OY
5a: R=Bn (85%)
5b: R=PMB (84%)
5c: R=H (72%)
6a: Y=H
6b: Y=Ac (73%)
g
h
c
O
OBn
OBn
O
OBn
13CH3
P
OBn
7 (62%)
O
Scheme 1 a) BnBr/NaH/DMF; b) PMBCl/NaH/DMF; c) (1) i-
Pr2NP(OBn)2/tetrazole/CH2Cl2; (2) H2O2; d) (1) 5% HCl/dioxane /
MeOH; (2) NaIO4/MeOH/H2O; (3) NaClO2/t-BuOH/H2O; (4) MeN-
HOMe-HCl/DCC/pyridine/CH2Cl2; e) 13CH3MgI/THF; f) H2, 10%
Pd-C/acetone/H2O; g) Ac2O/pyridine; h) DDQ/CH2Cl2/H2O
(o) Backstrom, A. D.; McMordie, R. A. S.; Begley, T. P. J.
Carbohydr. Chem. 1995, 14, 171. (p) David, S.;
Estramareix, B.; Fischer, J.-C.; Therisod, M. J. Chem. Soc.,
Perkin Trans. 1 1982, 2131. (q) For the synthesis of 1-
deoxy-L-xylulose, see tribenzoate: Wolfrom, M. L.; Bennet,
R. B. J. Org. Chem. 1965, 30, 458.
(3) Weinreb, S. M.; Folmer, J. J. In Encyclopedia of Reagents
for Organic Synthesis, Vol. 3; Paquette, L. A., Ed.; John
Wiley and Sons: Chichester, 1995, 2083.
(4) Chandrasekhar, M.; Kusum, K. L.; Singh, V. K. Tetrahedron
Lett. 2002, 43, 2773.
(5) The selected physical data are shown as follows.
4a: 1H NMR (500 MHz): d = 3.09 (s, 3 H), 3.43 (s, 3 H), 3.63
(dd, J = 5.5, 10.3 Hz, 1 H), 3.69 (dd, J = 5.5, 10.3 Hz, 1 H),
4.06 (dd, J = 5.5, 10.7 Hz, 1 H), 4.43–4.51 (m, 4 H), 4.63–
4.76 (m, 2 H), 7.25–7.35 (m, 15 H).
tions. The benzyl phosphate group was found to be reac-
tive toward the MeMgI reagent, where MeMgBr could
lead to the formation of the corresponding methyl ketone.
Consequently, protection of the primary alcohol 2 with
PMBCl was carried out. Conversion of the acetonide 3b
to the amide 4b5 proceeded with high yield, and subse-
quent treatment with 13CH3MgI gave rise to the 13C-la-
beled ketone 5b without any problems. The selective
deprotection of the PMB group with DDQ produced the
alcohol 5c, which was then subjected to phosphorylation.
The benzyl-protected substrate 7 was thus synthesized,
and the deprotection of 7 is already reported in the
literature2i using unlabeled compound.
Given the restricted 13C isotope source, a few further ma-
nipulations were inevitable for the preparation of the
phosphate after the introduction of the 1-13C-methyl
group. However, the final steps do not detract from the
overall efficiency of the synthetic route since only routine
steps are required.
4b: 1H NMR (500 MHz): d = 3.09 (s, 3 H), 3.44 (s, 3 H), 3.60
(dd, J = 5.4, 10.3 Hz, 1 H), 3.66 (dd, J = 5.2, 10.3 Hz, 1 H),
3.80 (s, 3 H), 4.04 (dd, J = 5.4, 10.7 Hz, 1 H), 4.30–4.40 (m,
2 H), 4.40–4.50 (m, 2 H), 4.60–4.80 (m, 3 H), 6.83 (d, J =
8.5 Hz, 2 H), 7.18 (d, J = 8.5 Hz, 2 H), 7.25–7.34 (m, 10 H).
5a: [a]D23 –36 (c 0.36, CHCl3). 1H NMR (500 MHz): d =
2.14 (d, J = 128 Hz, 13CH3), 3.60 (d, J = 6.1 Hz, 2 H), 3.95–
3.97 (m, 2 H), 4.39–4.45 (m, 3 H), 4.51 (d, J = 11.6 Hz, 1 H),
4.63 (d, J = 11.6 Hz, 1 H), 4.67 (d, J = 11.9 Hz, 1 H), 7.24–
7.34 (m, 15 H).
5b: [a]D23 –41 (c 1.0, CHCl3). 1H NMR (500 MHz): d = 2.13
(d, J = 127 Hz, 13CH3), 3.58 (d, J = 6.0 Hz, 2 H), 3.80 (s, 3
H), 3.93–3.96 (m, 2 H), 4.34 (d, J = 11.3 Hz, 1 H), 4.37 (d,
J = 11.3 Hz, 1 H), 4.43 (d, J = 11.7 Hz, 1 H), 4.50 (d,
J = 11.7 Hz, 1 H), 4.62 (d, J = 11.7 Hz, 1 H), 4.65 (d,
Synlett 2003, No. 10, 1521–1523 © Thieme Stuttgart · New York

LETTER
A Practical Access to [1-13C]1-Deoxy-D-xylulose and its Derivatives
1523
J = 11.7 Hz, 1 H), 6.85 (d, J = 8.6 Hz, 2 H), 7.18 (d, J = 8.6
7: [a]D23 –18 (c 0.35, CHCl3). 1H NMR (500 MHz): d = 2.09
(d, J = 128 Hz, 13CH3), 3.85 (d, J = 3.3 Hz, 1 H), 3.92 (ddd,
J = 3.3, 5.8, 6.0 Hz, 1 H), 4.06–4.14 (m, 2 H), 4.38 (d,
J = 11.5 Hz, 1 H), 4.41 (d, J = 11.5 Hz, 1 H), 4.53 (d,
J = 11.5 Hz, 1 H), 4.60 (d, J = 11.5 Hz, 1 H), 4.96–5.03 (m,
4 H), 7.18–7.35 (m, 20 H). 31P NMR: d = –6.4.
Hz, 2 H), 7.20–7.34 (m, 10 H).
6b: [a]D23 +35 (c 0.65, CHCl3). 1H NMR (500 MHz): d =
2.06, 2.08, 2.21 (s, OAc × 3), 2.21 (d, J = 129 Hz, 13CH3),
4.14 (dd, J = 6.6, 11.6 Hz, 1 H), 4.30 (dd, J = 5.8, 11.6 Hz, 1
H), 5.25 (d, J = 3.0 Hz, 1 H), 5.59 (ddd, J = 3.0, 5.8, 6.6 Hz,
1 H).
Synlett 2003, No. 10, 1521–1523 © Thieme Stuttgart · New York