Synthesis of analogues of the O-β-D-Ribofuranosyl nucleoside moiety of liposidomycins. Part 2: Role of the hydroxyl groups upon the inhibition of MraY

Article abstract of DOI:10.1016/S0960-894X(00)00714-9

O-β-D-Ribofuranosyl nucleoside I is the minimal structural entity of liposidomycins that maintains enzyme inhibitory activity on MraY. A set of compounds with hydroxyl patterns different from I has been synthesized. The presence of a hydroxyl group in the 3″ position is essential for the activity. The 3′-deoxy derivative (IV), however, shows a 5-fold improved potency.

Full text of DOI:10.1016/S0960-894X(00)00714-9

Bioorganic & Medicinal Chemistry Letters 11 (2001) 533±536
Synthesis of Analogues of the O-ꢀ-D-Ribofuranosyl Nucleoside
Moiety of Liposidomycins. Part 2: Role of the Hydroxyl Groups
upon the Inhibition of MraY
C. Dini,a,* N. Drochon,a J. C. Guillot,a P. Mauvais,b P. Waltera and J. Aszodia
aMedicinal Chemistry Department, Aventis Pharma, 102 route de Noisy, 93235 Romainville Cedex, France
bInfectious Disease Group, Aventis Pharma, 102 route de Noisy, 93235 Romainville Cedex, France
Received 4 October 2000; revised 4 December 2000; accepted 7 December 2000
AbstractÐO-b-d-Ribofuranosyl nucleoside I is the minimal structural entity of liposidomycins that maintains enzyme inhibitory
activity on MraY. A set of compounds with hydroxyl patterns di€erent from I has been synthesized. The presence of a hydroxyl
group in the 300 position is essential for the activity. The 30-deoxy derivative (IV), however, shows a 5-fold improved potency.
# 2001 Elsevier Science Ltd. All rights reserved.
Translocase (MraY) is an essential enzyme for bacteria.1
It catalyzes a key step during the synthesis of precursors
of peptidoglycan, before their assembly2 around the
bacterial cell. Compounds I and II (Fig. 1) that are
simpli®ed analogues of liposidomycins4 (LPMs), have
recently been shown as inhibitors of MraY. Their design
was the result of a thorough SAR analysis between
liposidomycins (LPMs), and tunicamycins (TCMs),5
another family of naturally occurring inhibitors of
translocase. The amino group and the uracil moiety
in this family of molecules play a crucial role in the
protein±inhibitor interaction.6
molecules related to I, missing at least one hydroxyl
group (Table 1).
Condensation of 13 with 27 (Scheme 1), in the presence
of tin tetrachloride, led to 3. Intermediate 3 was succes-
sively submitted to methanolysis, and to reduction with
PPh3 and H2O to provide III.8
Condensation of 43 with 59 (Scheme 2), in the presence
of mercury cyanide gave 6. Deprotection of the aceto-
nide group was accomplished by using 60% aqueous
acetic acid. Acetylation of the crude compound gave 7.
The introduction of the uracil moiety was performed
using a standard Vorbruggen procedure10 to give the
nucleoside 8. Methanolysis of 8 and subsequent reduc-
tion of the crude compound in the presence of PPh3 and
H2O in THF, gave the desired analogue IV.11
In order to assess the importance of the remaining polar
functions of I, we have undertaken the synthesis of
Concomitant protection of the 500 and 300 hydroxyl
groups of 93 with 1,3-dichloro 1,1,3,3-tetraisopropyl
disiloxane in pyridine gave 10 (Scheme 3). Thiocarbo-
nylation of 10 was accomplished with phenyl chloro-
thionoformate in the presence of DMAP leading to 11.
Deoxygenation of the 200 position of 11 was performed
with tributyltin hydride and AIBN to give 12. Regen-
eration of the hydroxyl groups in 500 and 300 positions
was achieved with tetrabutylammonium ¯uoride in
THF to give 13. Tosylation of the 500 hydroxyl group
was performed with toluenesulfonyl chloride in pyri-
dine. Tosylate substitution was carried out on the crude
Figure 1.
*Corresponding author. +33-(0)1-49-91-5480; fax: +33-(0)1-49-91-5087;
e-mail: christophe.dini@aventis.com
0960-894X/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved.
PII: S0960-894X(00)00714-9

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C. Dini et al. / Bioorg. Med. Chem. Lett. 11 (2001) 533±536
Table 1.
compound with sodium azide in DMF leading to the
azido compound 14. The acetonide protecting group
was cleaved o€ with 60% aqueous acetic acid and the
azido group hydrogenolyzed to give V.12
Compound 16 was prepared by silylation of the 50
position of 15 (commercially available) with tri-
methylsilyl chloride in the presence of DIEA and sub-
sequent protection of the uracil imide group with Boc
anhydride and DMAP as base (Scheme 4). Compound
18 was synthesized from 17,9 after cleavage of the acet-
onide protecting group and acetylation of resulting
hydroxyls. Compounds 16 and 18 were coupled using tri-
methylsilyl tri¯ate as catalyst to provide 19. Methanolysis
of 19, followed by reduction of the azido group with
Y20
Y30
Y200
Y300
III
IV
V
VI
VIII
H
OH
H
OH
OH
H
OH
OH
H
OH
OH
OH
OH
OH
H
OH
OH
OH
H
OH
Scheme 1. (a) SnCl4, CH2Cl2, 3 h, rt; (b) MeONa, MeOH, 18 h, rt; (c) PPh3, THF, H2O, 18 h, rt; (d) TFA/H2O (7:3), 30 min, rt.
Scheme 2. (a) Hg(CN)2, ClCH2CH2Cl, 18 h, rt; (b) 60% CH3CO2H aq, 10 h, 60 ꢀC; (c) Ac2O, pyridine, 3 h, rt; (d) O-O0-bis(trimethylsilyl)uracil,
TMSOTf, CH3CN, 3 h, rt; (e) MeONa, MeOH, 18 h, rt; (f) PPh3, THF, H2O, 18 h, rt.
Scheme 3. (a) 1,3-Dichloro 1,1,3,3-tetraisopropyl disiloxane, pyridine, 3 h, rt; (b) ClC(S)OPh, DMAP, CH3CN, 3 h, rt; (c) Bu3SnH, AIBN, PhCH3,
3 h, 80 ꢀC; (d) TBAF, THF, 3 h, rt; (e) TsCl, pyridine, 18 h, rt; (f) NaN3, DMF, 18 h, 70 ꢀC; (g) 60% CH3CO2H aq, 4 h, 60 ꢀC; (h) Pd/C, H2, MeOH,
30 min, rt.

C. Dini et al. / Bioorg. Med. Chem. Lett. 11 (2001) 533±536
535
Scheme 4. (a) TMSCl, DIEA, THF, 30 min, rt; (b) (BOC)2O, DMAP(cat.), TEA, THF, 2h, rt; (c) 60% CH 3CO2H aq, 2h, 70 ꢀC; (d) Ac2O, pyridine,
3 h, rt; (e) TMSOTf (cat. 10%), CH2Cl2, À10 ꢀC, 24 h; (f) MeONa, MeOH, 2 h, rt; (g) PPh3, THF, H2O, 72h, rt; (h) TFA/H 2O (7:3), 30 min, rt.
Scheme 5. (a) Hg(CN)2, ClCH2CH2Cl, rt, 18 h; (b) MeONa, MeOH, rt, 18 h; (c) Pd±C, H2, MeOH, 30 min, rt.
References
Table 2.
1. Boyle, D. S.; Donachie, W. D. J. Bacteriol. 1998, 180, 6429.
2. Struve, G. W.; Sinha, R. K.; Neuhaus, F. C. Biochemistry
1966, 5, 82 .
I
III
IV
V
VI
VII
IC50 (mM) on translocase
50
80
10
115
>1000
120
3. Aszodi, J.; Dini, C.; Collette, P.; Drochon, N.; Guillot,
J. C.; Lemoine, G.; Mauvais, P. Bioorg. Med. Chem. Lett.
2000, 10, 1839.
4. Kimura, K.; Ikeda, Y.; Kagami, S.; Yoshihama, M.;
Suzuki, K.; Osada, H.; Isono, K. J. Antibiot. 1998, 51, 1099
and references cited therein.
PPh3 in the presence of water, and subsequent cleavage
of the remaining protecting groups with 70% aqueous
tri¯uoroacetic acid, gave rise to VI.13
5. Takatsuki, A.; Kawamura, K.; Okina, M.; Kodama, Y.;
Ito, T.; Tamura, G. Agric. Biol. Chem. 1977, 41, 2307.
6. Dini, C.; Drochon, N.; Feteanu, S.; Guillot, J. C.; Peixoto,
C.; Aszodi, J. Bioorg. Med. Chem. Lett. 2001, 11, 529.
7. Lin, T. S.; Yang, J. H.; Liu, M. C.; Zhu, J. L. Tetrahedron
Lett. 1990, 31, 3829.
Condensation of 43 with 20 (commercially available), in
the presence of mercury(II) cyanide gave 21 (Scheme 5).
Methanolysis of 21 and subsequent hydrogenolysis of
the crude compound gave VII.14
8. Analytical data for III: 1H NMR (400 MHz, D2O): 2.41 (m,
2H, H20a, H20b), 2.81 (dd, 1H, J=8, 13.5 Hz, H500a), 3.06 (dd,
1H, J=3.5, 13.5 Hz, H500b), 3.67 (dd, 1H, J=5, 11.5 Hz,
H50a), 4.02±4.11 (m, 5H, H40, H50b, H200, H300, H400), 4.50 (m,
1H, H30), 5.05 (s, 1H, H100), 5.87 (d, 1H, J=8 Hz, H5), 6.28 (t,
1H, J=6 Hz, H10), 7.71 (d, 1H, J=8 Hz, H6). MS (FAB):
360+=(M+H+).
The inhibitory activity (IC50) of these compounds was
determined by using the assay mentioned in previous
publications.3,6 Results are summarized in Table 2.
According to these results, it appears that only the
hydroxyl in position 300 is crucial for the inhibition of
MraY. Removal of the 20-hydroxyl induced a slight
decrease in activity, whereas the e€ect is more pro-
nounced when the 200 hydroxyl or both 20 and 30 hydro-
xyls are removed. Conversely, the absence of the 30
hydroxyl gave rise to an inhibitor (IV), which was ®ve
times more potent.
9. Bentley, N.; Dowdeswell, C. S.; Singh, G. Heterocycles
1995, 41, 2499.
10. Niedballa, U.; Vorbruggen, H. J. Org. Chem. 1974, 39,
3668.
11. Analytical data for IV: 1H NMR (400 MHz, D2O): (acetic
acid salt): 1.92(s, CH , acetic acid salt), 2.07 (m, 2H, H30a,
3

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C. Dini et al. / Bioorg. Med. Chem. Lett. 11 (2001) 533±536
H30b), 3.06 (dd, 1H, J=9.5, 13.5 Hz, H500a), 3.39 (dd, 1H,
J=3, 13.5 Hz, H500b), 3.71 (dd, 1H, J=5, 12Hz, H5 0a), 4.54
(m, 1H, H20), 4.12±4.23 (m, 4H, H50b, H20, H30, H40), 4.64 (m,
1H, H40), 5.11 (s, 1H, H100), 5.83 (d, 1H, J=1 Hz, H10), 5.86
(d, 1H, J=8 Hz, H5), 7.78 (d, 1H, J=8 Hz, H6); MS (ESI):
360+=(M+H+).
2.22 (ddd, 1H, J=7, 14 Hz, H300b), 2.94 (dd, 1H, J=9.5,
13 Hz, H500a), 3.27 (dd, 1H, J=2.5, 13 Hz, H500b), 3.74 (dd,
1H, J=5, 11.5 Hz, H50a), 4.12(dd, 1H, J=2.5, 11.5 Hz, H50b),
4.24 (m, 1H, H40), 4.28 (dd, 1H, J=5, 6 Hz, H30), 4.35 (dd,
1H, J=4, 5 Hz, H20), 4.40 (d, 1H, J=4.5 Hz, H200), 4.59 (ddt,
1H, J=2.5, 7, 9 Hz, H400), 5.11 (s, H100), 5.90 (d, 1H, J=4 Hz,
H10), 5.92(d, 1H, J=8 Hz, H5), 7.74 (d, 1H, J=8 Hz, H6).
MS (ESI): 360+=(M+H+).
14. Analytical data for VII: 1H NMR (400 MHz, D2O): 1.87±
2.55 (m, 4H, H20a, H20b, H30a, H30b), 2.89 (dd, 1H, J=8.5,
13 Hz, H500a), 3.17 (dd, 1H, J=3, 13 Hz, H500b), 3.63 (dd, 1H,
J=5.5, 11.5 Hz, H50a), 4.04 (dd, 1H, J=2.5, 11.5 Hz, H50a),
4.02±4.16 (m, 3H, H200, H300, H400), 4.34 (m, 1H, H40), 5.06 (s,
1H, H100), 5.86 (d, 1H, J=8 Hz, H5), 6.12(dd, 1H, J=3,
7 Hz, H10), 7.79 (d, 1H, J=8 Hz, H6). MS (ESI):
344+=(M+H+).
12. Analytical data for V: 1H NMR (400 MHz, CD3OD): 2.11
(ddd, 1H, J=5.5, 7, 13 Hz, H200a), 2.24 (ddd, 1H, J=2, 7,
13 Hz, H200b), 2.73 (dd, 1H, J=8, 13 Hz, H500a), 2.89 (dd, 1H,
J=4, 13 Hz, H500b), 3.60 (m, 1H, H50a), 3.87 (m, 1H, H400),
4.05±4.15 (m, 4H, H50b, H20, H30, H40), 4.24 (dt, 1H, J=5,
7 Hz, H300), 5.27 (dd, 1H, J=2, 5.5 Hz, H100), 5.72(d, 1H,
J=8 Hz, H5), 5.86 (d, 1H, J=3.5 Hz, H10), 7.85 (d, 1H,
J=8 Hz, H6). MS (SIMS): 360+=(M+H+).
13. Analytical data for VI (tri¯uoroacetate form): 1H NMR
(400 MHz, CD3OD): 1.92(ddd, 1H, J=4.5, 9, 14 Hz, H300a),