Synthesis and preliminary screening of O-β-D-galactopyranosides as potential mimic of UDP-Gal p against mycobacterium tuberculosis

Article abstract of DOI:10.1080/07328303.2011.654017

O-Galactopyranosides were synthesized as potential mimics of uridine 5c-diphosphate galactopyranose (UDP-Galp), which is the substrate of the mutase enzyme involved in the mycobacterial cell wall biosynthesis by converting UDP-Galp to UDP-Galf. In vitro a

Full text of DOI:10.1080/07328303.2011.654017

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Synthesis and Preliminary Screening
of O-β-D-Galactopyranosides as
Potential Mimic of UDP-Galp against
Mycobacterium tuberculosis
b
a
a
G. Mugunthan , Dharmarajan Sriram , Perumal Yogeeswari & K.
b
P. Ravindranathan Kartha
a
Department of Medicinal Chemistry, National Institute of
Pharmaceutical Education and Research, S.A.S. Nagar, Punjab,
1
60062, India
b
Medicinal Chemistry & Antimycobacterial Research Laboratory,
Pharmacy Group, Birla Institute of Technology and Science,
Hyderabad, 500078, India
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Kartha (2012): Synthesis and Preliminary Screening of O-β-D-Galactopyranosides as Potential Mimic of
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Journal of Carbohydrate Chemistry, 31:553–570, 2012
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 0732-8303 print / 1532-2327 online
DOI: 10.1080/07328303.2011.654017
Synthesis and Preliminary
Screening of O-β-D-
Galactopyranosides as
Potential Mimic of UDP-Galp
against Mycobacterium
tuberculosis
1
1
2
G. Mugunthan, Dharmarajan Sriram, Perumal Yogeeswari,
and K. P. Ravindranathan Kartha2
1Department of Medicinal Chemistry, National Institute of Pharmaceutical Education
and Research, S.A.S. Nagar, Punjab-160062, India
2
Medicinal Chemistry & Antimycobacterial Research Laboratory, Pharmacy Group,
Birla Institute of Technology and Science, Hyderabad-500078, India
O-Galactopyranosides were synthesized as potential mimics of uridine 5c-diphosphate
galactopyranose (UDP-Galp), which is the substrate of the mutase enzyme involved in
the mycobacterial cell wall biosynthesis by converting UDP-Galp to UDP-Galf. In vitro
assay against the Mycobacterium tuberculosis H37Rv strain gave promising results with
minimum inhibitory concentration (MIC) values in the range of 3.13 to 25 µg/mL.
Keywords Mycobacterium tuberculosis; Cell wall biosynthesis; UDP-galactopyranose
(
UDP-Galp) mutase; UDP-Galp mimics; Antimycobacterial agents
INTRODUCTION
Tuberculosis (TB) remains one of the leading causes of mortality, and its coin-
fection with HIV further worsens the situation. The major hurdles in the treat-
ment of TB are latency and drug resistance. A recent WHO progress report on
multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB points
Received July 13, 2011; accepted December 28, 2011.
Address correspondence to K. P. Ravindranathan Kartha, Department of Medicinal
Chemistry, National Institute of Pharmaceutical Education and Research, S.A.S. Na-
gar, Punjab-160062, India. E-mail: rkartha@niper.ac.in
5
53

54 G. Mugunthan et al.
5
out that 69 countries reported at least one case of XDR-TB, which is resis-
tant to isoniazid and rifampicin, as well as any fluoroquinolone and any of the
second-line anti-TB injectable drugs such as amikacin, kanamycin, or capre-
omycin. According to WHO estimates, 25,000 cases of XDR-TB emerge every
year.[ Emergence of extensive drug resistance emphasizes the need for new
drugs with novel modes of action.
1]
Sugar nucleotides play an important role in carbohydrate metabolism. The
biosynthesis of the carbohydrate-rich mycobacterial cell wall depends on sugar
nucleotides for the construction of a complex cell wall assembly. Inhibitors of
enzymes involved in carbohydrate metabolism can be of therapeutic use in
various complications, including tuberculosis. Galactofuranose (Galf) is the
abundant and vital part of the arabinogalactan portion of the mycobacterial
cell wall. Uridine 5c-diphosphate galactopyranose (UDP-Galp) was identified
as a precursor for Galf residue in microbes, particularly in Mycobacterium
smegmatis arabinogalactan biosynthesis.[ UDP-Galp is converted to uridine
2]
5c-diphosphate galactofuranose (UDP-Galf) by UDP-galactopyranose mutase
(UGM). Galf is then transferred from UDP-Galf to the respective glycoconju-
gate molecule by specific galactofuranosyl transferases.
Absence of UGM and hence Galf in mammals, along with the fact that
biosynthesis of Galf residue is essential for cell wall biosynthesis and the vi-
ability of mycobacteria, makes Galf metabolism a potential selective target
for antimycobacterial chemotherapy.[ Different substrate and transition state
mimics of the Galf residue have thus been synthesized and screened against
3]
[
4–6]
UGM in the recent past.
One of the common approaches toward designing a sugar nucleotide mimic
is to replace the phosphate bridge with other suitable units that are more sta-
ble and can facilitate binding in the active site.[ In the case of transferases,
inhibitory molecules in which the pyrophosphate residue has been substituted
by a diol that can potentially complex with the divalent metal ion found in
the active site of the enzyme have been proved successful in some cases. The
best example for this class of compounds is tunicamycin (Fig. 1), an antibi-
otic produced by Streptomyces lysosuperificus, which acts as an inhibitor of
dolichol-pyrophosphate-D-GlcNAc-synthase (DPGS).[
7,8]
9]
Figure 1: Comparison of UDP-GlcNAc and tunicamycin.

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
55
OH
2+
OH
HO
M
2
+
O
M
O
OH
O
HO
O
O
NH
OH
HO
OH
HO
NH
O
O
O
O
O
P
P
N
O
O
O
N
O
N
H
O
O
O
HO
HO
OH
4
3
HO
Potential UDP-Galp mimic
OH
UDP-Galp: Original substrate f or mutase
Figure 2: Comparison of UDP-Galp and a potential mimic of UDP-Galp.
There are also other examples in which hydroxyl-bearing moieties have
been found to be useful as a surrogate for the pyrophosphate, for exam-
[
10,11]
ple, inhibitors with glucose residue in the place of pyrophosphate
and
vicinal diols as a surrogate for pyrophosphate[
12,13]
that were shown to be
successful mimics of pyrophosphate residue. As part of the ongoing antimy-
cobacterial drug discovery project, we synthesized and screened some O-
galactopyranosides with a hydroxyl group in the protected form in the place
of the pyrophosphate as a potential mimic of UDP-Galp (Fig. 2). Even though
the α-anomer of the compound would be the exact mimic of the substrate, in
the proposed molecules here we incorporated the β-linkage in order to investi-
gate its possible role as a competitive inhibitor and thus to ascertain whether
or not the anomeric configuration is of marked bearing in the potential enzyme
inhibition, aside from the fact that they are easier to access.
RESULTS AND DISCUSSION
Chemistry
For the synthesis of the UDP-Galp mimics discussed above, the re-
quired sugar donor and the appropriately protected tris(hydroxymethyl)
[
14]
aminomethane acceptor 5
were prepared and were subjected to glycosyla-
tion reaction to get the desired intermediate capable of elaboration into di-
versified structural mimics. Thus, D-galactose was converted to its peracetate
using the iodine-mediated esterification of alcohols[
15]
in near-quantitative
yield. The peracetate obtained was then converted to 2,3,4,6-tetra-O-acetyl-
[
16]
α-D-galactopyranosyl bromide
by treatment with 33% HBr in AcOH in good
yield and was subjected to glycosylation with the appropriately protected 5
under Helferich conditions using Hg(CN)2 in anhydrous CH3CN to get the β-
O-galactopyranoside 6, which upon hydrogenolysis gave the amine 7 (Sch. 1).
The amine 7 was conveniently derivatized by treating with carboxylic
acids, acid chlorides, isocyanates, and isothiocyanates containing function-
alized aromatic moiety, to take advantage of any possible hydrogen bond-
ing and/or π-stacking interaction in the enzyme active site. Carboxylic

56 G. Mugunthan et al.
5
Scheme 1: Synthesis of tris-linked galactopyranosyl unit.
ꢁ
ꢁ
ꢁ
acids, including 2 ,3 -O-isopropylidene uridine 5 -carboxylic acid, which can
closely resemble UDP-Galp, prepared according to the reported procedure,[
were coupled to the amine using a combination of benzotriazol-1-yl-oxy-
trispyrrolidinophosphonium hexafluorophosphate (PyBOP) and hydroxyben-
zotriazole (HOBt) along with di-isopropylethylamine (DIPEA) in anhydrous
DMF to get the amide-linked products 8a–f (Sch. 2). Similarly, the amine 7 was
also treated with selected acid chlorides in neat anhydrous pyridine to give the
corresponding amide-linked products 8g–h in very good yields (Sch. 2). Like-
wise, when the amine 7 was treated with aromatic isocyanates and isothio-
cyanates in anhydrous DMF, the corresponding urea (9a–e) and thiourea (10a
and 10b) derivatives were also obtained in very good yields.
17]
Scheme 2: Generation of urea, thiourea, and amide-linked UDP-Galp mimics.
Biology
After the UDP-Galp analogs were synthesized, they were screened against
M. tuberculosis H37Rv without subjecting them to any deprotection reaction,
because literature precedence has shown better enzyme inhibitory properties
for the partially and fully protected sugar derivatives than the correspond-
[
18–20]
ing completely deprotected ones.
Compared to the deprotected molecules,
the corresponding protected derivatives can be expected to have the re-
quired lipophilicity necessary for the molecule to gain entry through the waxy

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
57
mycobacterial cell wall. Also, the protecting groups such as the acetate and
the isopropylidene acetal would be susceptible to deprotection by the enzy-
matic process involved in metabolism in the microbe generating the depro-
tected analogs in situ. Besides, the protected molecules as such may also act
as inhibitors.
Results of the in vitro screening using the agar dilution method along
with the values obtained for the three standard first-line drugs isoniazid,
rifampicin, and ethambutol as positive controls are summarized in Table 1.
It can be seen from the table that minimum inhibitory concentration (MIC)
values were in the range of 3.13 to >25 µg/mL for the compounds. In the
case of the amide-linked analogs, compound 8a, having the uridine moiety
closely resembling the substrate UDP-Galp, showed moderate inhibition with
a MIC of 12.5 µg/mL. Compound 8d containing the pyrazine moiety also gave
a similar result, and the one containing the 2-chloropyridyl group showed
an improved MIC of 6.25 µg/mL. Compound 8f containing the Boc-protected
histidine residue gave the most promising result, with the MIC at 3.13 µg/mL,
closer to the corresponding value of 1.56 µg/mL for ethambutol, one of the
positive controls used in the assay. In the case of urea-linked derivatives,
again, the one with furan residue (compound 9a) resembling the ribofuranose
part of the uridine gave a moderate result, with a MIC of 12.5 µg/mL. For
the urea-linked products, electron-withdrawing substituents were found
to increase the activity. For example, compound 9e containing lipophilic
electron-withdrawing trifluoromethyl substitution gave a MIC of 6.25 µg/mL,
and compound 9b containing the electron-withdrawing nitro group in the para
position of the substituent phenyl ring was proved to be the best in this class,
with an MIC value of 3.13 µg/mL.
In the case of the thiourea-linked products, the nature of the halogen in the
ortho position of the substituent phenyl ring seemed to influence the activity
of the compounds, as compound 10a with chloro substituents on the ortho po-
sitions of the phenyl ring was found to be superior to the analogous compound
10b bearing bromo and fluoro substitutions instead.
From the preliminary results, it is seen that apart from the analogy with
the original substrate, lipophilicity, electronic, and hydrogen bonding proper-
ties are also important in imparting biological activity to the molecules. This
is amply evident by comparing compounds 9b and 9c. Though 9c possessed
an electron-withdrawing chloro substituent in the para position of the phenyl
ring, it lacked the hydrogen bonding interaction as in the case of the nitro
group in compound 9b. Similarly, the relatively better activity observed for
compound 8f could be possibly attributed to the hydrogen bonding ability of the
histidine residue along with the lipophilicity of the Boc protection on it. Com-
pound 8c possessing a uracil residue was expected to be more active but per-
formed poorer, probably because of the comparatively low lipophilicity. Thus,
overall, it may be inferred that optimum lipophilicity, along with electronic and

58 G. Mugunthan et al.
5
Table 1: In vitro assay results against Mycobacterium tuberculosis H37Rv
OAc
OAc
O
O
O
AcO
O
R
AcO
Yield MIC
Yield MIC
Entry
1
R
%
(µg/mL) Entry
R
%
(µg/mL)
O
N
72
12.5
8
O
92
25
N
NH
N
H
O
O
O
8
h
N
H
O
O
8
a
2
3
H
76
67
25
9
O
82
12.5
3.13
N
O
N
N
O
H
H
8
b
S
9a
O
>25
10
NO2 91
O
NH
H
N
N
H
N
N
H
O
H
9b
O
8
c
4
5
O
69
71
12.5
25
11
12
Cl
85
88
25
25
O
N
N
N
H
N
H
N
H
8
d
9c
9d
O
O
N
H
N
H
N
H
N
BocNH
NBoc
8e
6
NHBoc
68
3.13
13
CF3
84
6.25
NBoc
H
N
O
N
O
8f
N
H
N
CF
3
H
9e
(
Continued on next page)

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
59
Table 1: In vitro assay results against Mycobacterium tuberculosis H37Rv
(
Continued)
OAc
OAc
O
O
O
AcO
O
R
AcO
Yield
%
MIC
(µg/mL) Entry
Yield
%
MIC
Entry
7
R
R
(µg/mL)
O
Cl
90
6.25
14
Cl
76
12.5
S
N
H
N
N
H
N
H
8g
Cl
10a
15
Br
79
25
16
Ethambutol
Isoniazid
Rifampicin
–
–
–
1.56
0.05
0.10
S
N
H
N
H
F
10b
MIC = minimum concentration required for complete inhibition.
hydrogen bonding properties of the substituents, plays the determining role in
activity of the compounds studied.
In conclusion, synthetic analogs of UDP-Galp were prepared and screened
against M. tuberculosis H37Rv, leading to some promising compounds with
MICs as low as 3.13 µg/mL. Based on the initial findings, preparation of
the analogous compounds in α-configuration, with and without the protecting
groups, is currently under way to facilitate a detailed SAR study. This may lead
to potentially more active compounds, which will be subsequently subjected to
detailed enzyme inhibition assays and toxicity studies.
EXPERIMENTAL
Materials and Methods
All reagents and chemicals were purchased from Sigma-Aldrich and were
used without further purification. TLC analyses were performed on 0.2-mm
Merck precoated silica gel 60 F254 aluminium sheets and the spots were visu-
alized under UV lamp and/or by immersion in an ethanolic solution of sulfuric
acid (5%, v/v) followed by heating. Final purifications were performed using sil-
ica gel 200–400 mesh size. Melting points were determined on a B u¨ chi melting
point (B-540) apparatus and are uncorrected. Specific rotations were recorded

60 G. Mugunthan et al.
on a Rudolph Autopol IV Polarimeter at 20 C. NMR spectra were recorded on
5
◦
1
13
a Bruker Avance DPX (400 MHz) spectrometer. H NMR and C NMR spec-
tra were referenced to the internal standard tetramethylsilane, in the respec-
tive deuterated solvents. IR spectra were recorded on a Nicolet FT-IR Impact
410 instrument either as thin film (neat) or as KBr pellet. Mass spectra were
recorded on a MALDI (Bruker Daltonics, Ultraflex TOF/TOF) spectrometer.
Agar Dilution Method
Tenfold serial dilutions of each test compound/drug were incorporated into
Middlebrook 7H11 agar medium with OADC Growth Supplement (drug con-
centrations from 12.5 µg/mL to 0.78 µg/mL). Inoculum of M. tuberculosis
H37Rv was prepared from fresh Middlebrook 7H11 agar slants with OADC
Growth Supplement was adjusted to 1 mg/mL (wet weight) in Tween 80
(0.05%) saline diluted to 10-2 to give a concentration of approximately 107
cfu/mL. A 5-µL amount of bacterial suspension was spotted into 7H11 agar
tubes containing 10-fold serial dilutions of drugs per milliliter. The tubes were
◦
incubated at 37 C, and final readings were recorded after 28 days. The MIC is
defined as the minimum concentration of the compound required to give the
complete inhibition of bacterial growth.
ꢀ
ꢀ
ꢀ
ꢀ
Synthesis of 5-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)
oxymethyl]-5-(N-benzyloxycarbonyl)-2,2-dimethyl-1,3-
dioxane (6)
To a mixture of the acceptor 5 (5.4 mmol) and mercuric cyanide (5.9 mmol)
in anhydrous CH3CN (75 mL) at rt under an inert atmosphere was added
dropwise a solution of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide
(7.5 mmol) in anhydrous CH3CN (10 mL). After completion of the reaction,
the mixture was diluted with CH2Cl2 and was extracted with an aqueous so-
lution of KI followed by extraction with aqueous bicarbonate and finally with
brine. The organic layer was dried over anhydrous sodium sulfate and was
concentrated under reduced pressure. The crude product was subjected to chro-
matographic purification by gradient elution using EtOAc and hexane to get 6
(
2.5 g) as a colorless solid.
◦
Yield 75%; mp 110.5–111.8 C (crystallized from ether and petroleum
1
ether); [α]D –11.0 (c 1, CHCl3); H NMR (400 MHz, CDCl3) δ 7.37–7.33 (m, 5H,
Ar-H), 5.36 (dd, J4
5
4
ꢁ
ꢁ
ꢁ
= 0.9 Hz, J
ꢁ ꢁ
= 3.4 Hz, 1H, H-4 ), 5.25 (s, 1H, -CONH-),
,5
3 ,4
ꢁ
.17 (dd, J1
ꢁ
ꢁ
= 7.9 Hz, J
ꢁ ꢁ
2 ,3
= 10.5 Hz, 1H, H-2 ), 5.06 (s, 2H, -OCH2Ph),
,2
ꢁ
.97 (dd, J3
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.42 (d, J
ꢁ ꢁ
1 ,2
= 7.8 Hz, 1H,
,4
2 ,3
ꢁ
H-1 ), 4.17, 3.75 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.12 (d, J5ꢁ ,6ꢁ = 6.6 Hz, 2H,
ꢁ
H-6 a,b), 4.07 (d, J = 11 Hz, 2H, -C-CH2O-), 3.92 (d, J = 10 Hz, 1H, -C-CH2O-),
ꢁ
3
.84–3.81 (m, 3H, H-5 and-C-CH2O-), 2.14, 2.04, 2.00, 1.98 (4 × s, 12H, 4 ×

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
61
1
3
-
COCH3), 1.47, 1.35 (2 × s, -C(CH3)2); C NMR (100 MHz, CDCl3) δ 170.37,
1
1
6
70.22, 170.07, 169.50 (4 × -COCH3), 155.15 (BnO-CO), 136.18, 128.59,
ꢁ
ꢁ
ꢁ
28.28, 128.17 (6 × Ar-C), 101.73 (C-1 ), 98.52 (C-2), 70.79 (C-5 ), 70.65 (C-3 ),
ꢁ
ꢁ
9.67 (-CH2O-), 68.74 (C-2 ), 66.95 (C-4 ), 66.61 (Ar-CH2-), 63.06, 62.13 (C-4
ꢁ
and C-6), 61.23 (C-6 ), 52.02 (C-5), 23.83, 23.30 (-C(CH3)2), 20.67, 20.57 (4 ×
−1
COCH3); IR (Neat) νmax 3361, 2991, 1751, 1714, 1524, 1371, 1224, 1076 cm ;
HRMS: m/z calculated for C29H39NNaO14: 648.2268. Found: 648.2253.
ꢀ
ꢀ
ꢀ
ꢀ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-
-amino-2,2-dimethyl-1,3-dioxane (7)
5
To a solution of 6 (2 g) in ethanol (30 mL) was added 10% Pd/C (0.2 g),
which was then subjected to 60 psi hydrogen pressure using a Parr hydrogentor
for 5 h. After the completion of the reaction, the reaction mixture was filtered
through a Celite bed to remove solids and the filtrate was concentrated under
reduced pressure to get 7 (1.5 g) as a colorless solid.
◦
Yield 95%; mp 122.5–123.2 C (crystallised from methanol); [α]D –8.3 (c 1,
1
CHCl3); H NMR (400 MHz, CDCl3) δ 5.39 (dd, J
ꢁ
ꢁ
= 0.9 Hz, J
ꢁ
ꢁ
= 3.4 Hz,
4
,5
3 ,4
ꢁ
ꢁ
1
J3
H, H-4 ), 5.21 (dd, J1
ꢁ
ꢁ
= 7.8 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 5.02 (dd,
,2
2 ,3
ꢁ
ꢁ
ꢁ
ꢁ
= 3.4 Hz, J2,3 = 10.5 Hz, 1H, H-3 ), 4.48 (d, J
ꢁ ꢁ
1 ,2
= 7.8 Hz, 1H, H-1 ),
,4
ꢁ
4
J5
.15 (dd, J
ꢁ
ꢁ
= 6.6 Hz, J
ꢁ
ꢁ
= 11.2 Hz, 2H, H-6 a,b), 3.91 (dt, J
ꢁ ꢁ
4 ,5
= 0.9 Hz,
5
,6
6 a,6 b
ꢁ
ꢁ
ꢁ
= 6.6 Hz, 1H, H-5 ), 3.82, 3.57 (2 × d, J = 9.4 Hz, 2H, -C-CH2O-), 3.77,
,6
3
.48 (2 × d, J = 11.5 Hz, 2H, -C-CH2O-), 3.73, 3.53 (2 × d, J = 11.7 Hz, 2H,
-
C-CH2O-), 2.16, 2.06, 2.05, 1.98 (4 × s, 4 × 3H, 4 × -COCH3), 1.43, 1.40 (2 ×
1
3
s, -C(CH3)2); C NMR (100 MHz, CDCl3) δ 170.40, 170.24, 170.10, 169.53 (4 ×
ꢁ
ꢁ
ꢁ
-
6
COCH3), 101.73 (C-1 ), 98.22 (C-2), 72.93 (O-CH2-), 70.76 (C-5 ), 70.72 (C-3 ),
ꢁ
ꢁ
ꢁ
8.90 (C-2 ), 67.26 (C-4/C-6), 66.99 (C-4 ), 66.62 (C-4/C-6), 61.25 (C-6 ), 49.14
(
C-5), 24.05, 23.02 (-C(CH3)2), 20.77, 20.67, 20.57 (4 × COCH3); IR (Neat)
−1
νmax 3463, 2991, 2869, 1750, 1371, 1224, 1059 cm ; HRMS: m/z calculated
for C21H33NNaO12: 514.1900. Found: 514.1912.
General Procedure for the Coupling Reaction (Amide Bond
Formation) Using an Acid and an Amine
The desired caboxylic acid (1 mmol) was codissolved with PyBOP
(1.1 mmol) and HOBt (1.1 mmol) in anhydrous DMF (10 mL). To this solu-
tion was added DIPEA (1 mmol) followed by the addition of amine 7 (1 mmol),
and this was stirred under an inert atmosphere for 24 h. After the completion
of the reaction, the solvent was evaporated off under reduced pressure and the
crude was subjected to chromatographic purification by gradient elution using
EtOAc and hexane.

62 G. Mugunthan et al.
5
ꢁ
ꢁ
ꢁ
ꢁ
ꢁꢁ ꢁꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-(2 ,3 -is
ꢁ
ꢁ
opropylidene-uridine-4 -carboximido)]-2,2-dimethyl-1,3-dioxane (8a)
1
Yield 72%; Colorless syrup; [α]D –2.6 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 9.05 (s, 1H, -CONHCO-), 7.25 (d, J = 8.0 Hz, 1H, uracil H-6), 6.49 (s,
1
H, -CONH-), 5.75 (d, J = 8.0 Hz, 1H, uracil H-5), 5.53 (d, J
ꢁ
ꢁ
2
= 1.3 Hz, 1H,
1
ꢁ
ꢁ
H-1 ), 5.39 (dd, J
J2ꢁ,3
J3
ꢁ
ꢁ
= 1.0 Hz, J
ꢁ
ꢁ
= 3.2 Hz, 1H, H-4 ), 5.23 (dd, J
ꢁ
ꢁ
= 3.0 Hz,
4
,5
3 ,4
3 ,4
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
= 6.4 Hz, 1H, H-3 ), 5.16–5.07 (m, 3H, H-2 , H-2 and H-3 ), 4.52 (d,
ꢁ
ꢁ
ꢁ
ꢁ
= 3.0 Hz, 1H, H-4 ), 4.50 (d, J
ꢁ ꢁ
1 ,2
= 7.2 Hz, 1H, H-1 ), 4.33, 3.59 (2 ×
,4
d, J = 11.8 Hz, 2H, C-CH2O-), 4.31, 3.82 (2 × d, J = 10.5 Hz, 2H, C-CH2O-),
4
2
2
.22, 3.80 (2 × d, J = 11.7 Hz, 2H, C-CH2O-), 4.14 (d, J
ꢁ
ꢁ
,6
= 6.6 Hz, = 7 Hz,
5
ꢁ
ꢁ
H, H-6 a,b), 3.92 (dt, J
ꢁ
ꢁ
= 0.9 Hz, J
ꢁ ꢁ
5 ,6
= 6.6 Hz, 1H, H-5 ), 2.19, 2.08,
4
,5
.07, 2.00 (4 × s, 12H, 4 × -COCH3), 1.55, 1.45, 1.38, 1.36 (4 × s, 12H, 2 ×
1
3
-
-
C(CH3)2); C NMR (100 MHz, CDCl3) δ 170.50, 170.39, 170.33, 170.29 (4 ×
COCH3), 169.63 (-NHCO-), 162.58, 149.95 (2 × uracil -NHCO-), 143.24 (uracil
ꢁ
C-6), 114.17 (-C(CH3)2), 102.86 (uracil C-5), 101.91 (C-1 ), 98.52 (C-2) 98.04
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
(
(
6
C-1 ), 88.23 (C-4 ), 83.90 (C-2 ), 83.52 (C-3 ), 71.07 (C-5 ), 70.66 (C-3 ), 69.86
ꢁ
ꢁ
ꢁ
O-CH2-), 69.21 (C-2 ), 67.01 (C-4 ), 62.44 (C-4/C-6), 61.37 (C-6 ), 60.99 (C-4/C-
), 53.03 (C-5), 26.79, 24.92, 24.00, 23.25 (2 × -C(CH3)2, 20.85, 20.70, 20.61 (4 ×
COCH3); IR (Neat) νmax 3403, 3072, 2985, 2934, 1750, 1692, 1454, 1375, 1223,
−1
1
078, 1049, 825 cm ; HRMS: m/z calculated for C33H45N3NaO18: 794.2596.
Found: 794.2589.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-(N-[(4-met
hylthio benzyl)carboximido)]-2,2-dimethyl-1,3-dioxane (8b)
1
Yield 76%; Thick syrup; [α]D –10.5 (c 1, CHCl3); H NMR (400 MHz, CDCl3)
δ 7.24–7.19 (m, 4H, Ar-H), 5.80 (s, 1H, -CONH-), 5.38 (dd, J
ꢁ
ꢁ
= 0.9 Hz,
4
,5
ꢁ
J
2
1
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.17 (dd, J1ꢁ ,2ꢁ = 7.8 Hz, J
ꢁ ꢁ
= 10.5 Hz, 1H, H-
3
ꢁ
,4
2 ,3
ꢁ
), 5.00 (dd, J
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.43 (d, J
ꢁ ꢁ
1 ,2
= 7.8 Hz,
3
,4
2 ,3
ꢁ
H, H-1 ), 4.18, 3.73 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.13, 3.92 (2 × d,
ꢁ
J = 10.0 Hz, 2H, C-CH2O-), 4.13 (d, J
ꢁ
ꢁ
,6
= 6.6 Hz, 2H, H-6 a, b), 4.00, 3.81
5
(
2 × d, J = 11.8 Hz, 2H, C-CH2O-), 3.90 (dt, J
ꢁ
ꢁ
= 1.0 Hz, J
ꢁ ꢁ
5 ,6
= 6.6 Hz,
4
,5
ꢁ
1
1
H, H-5 ), 3.48 (s, 2H, Ar-CH2CO-), 2.47 (s, 3H, Ar-SCH3), 2.16, 2.05, 2.04,
1
3
.99 (4 × s, 12H, 4 × -COCH3), 1.59, 1.37 (2 × s, 6H, -C(CH3)2); C NMR
(
100 MHz, CDCl3) δ 171.51, 170.39, 170.19, 170.04, 169.51 (4 × -COCH3 and
ꢁ
ꢁ
-
CONH-), 137.53, 131.50 (2 × Ar-C), 129.73, 127.17 (4 × Ar-CH), 101.51 (C-1 ),
ꢁ
ꢁ
ꢁ
9
6
2
8.47 (C-2), 70.84 (C-5 ), 70.61 (C-3 ), 69.30 (O-CH2-), 68.86 (C-2 ), 66.97 (C-4 ),
ꢁ
2.71, 62.09 (C-4 and C-6), 61.16 (C-6 ), 53.12 (C-5), 43.73 (-O-CH2-Ar), 24.78,
2.27 (-C(CH3)2), 20.79, 20.68, 20.56 (4 × -COCH3), 15.88 (ArS-CH3); IR (Neat)
−
1
νmax 3362, 2985, 2920, 1750, 1672, 1370, 1222, 1076, 1046 cm ; HRMS: m/z
calculated for C30H41NNaO13S: 678.2196. Found: 678.2190.

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
63
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-(uracil-6-
carboximido)]-2,2-dimethyl-1,3-dioxane (8c)
1
Yield 67%; Thick syrup; [α]D –10.5 (c 0.5, MeOH); H NMR (400 MHz,
ꢁ
CD3OD) δ 6.18 (s, 1H, uracil H-5), 5.38 (d, J
ꢁ
ꢁ
= 2.8 Hz, H-4 ), 5.12–5.09
3
,4
ꢁ
ꢁ
ꢁ
(
4
m, J1
ꢁ
ꢁ
= 7.2 Hz, 2H, H-2 and H-3 ), 4.64 (d, J
ꢁ ꢁ
1 ,2
= 7.2 Hz, 1H, H-1 ), 4.18,
,2
.03 (2 × d, J = 10 Hz, 2H, C-CH2O-), 4.17, 3.98 (2 × d, J = 11.9 Hz, 2H,
C-CH2O-), 4.09, 3.96 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.10 (brs, 3H, H-
ꢁ
ꢁ
5
and H-6 a,b), 2.15, 2.03, 1.95 (3 × s, 12H, 4 × -COCH3), 1.43, 1.41 (2 ×
1
3
s, -C(CH3)2); C NMR (100 MHz, CD3OD) δ 172.21, 172.09, 171.56, 171.54
ꢁ
(
4 × COCH3), 166.91, 162.42 (-NHCO-), 102.18 (C-1 ), 101.59 (uracil C-5),
ꢁ
ꢁ
ꢁ
1
4
2
1
00.02 (C-2), 71.96 (C-5 ), 70.45 (C-3 ), 69.01 (C-2 ), 68.76 (-CH2O-), 67.38 (C-
ꢁ
ꢁ
), 63.69, 63.18 (C-4 and C-6), 62.60 (C-6 ), 55.72 (C-5), 23.93, 23.87 (-C(CH3)2,
0.75, 20.60, 20.53, 20.50 (4 × -COCH3); IR (KBr) νmax 3404, 2992, 2927, 2855,
−1
749, 1674, 1558, 1493, 1427, 1376, 1234, 1078, 1046, 849 cm ; HRMS: m/z
calculated for C26H35N3NaO15: 652.1966. Found: 652.1943.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-(N-(1,4-pyr
azine-2-carboximido}-2,2-dimethyl-1,3-dioxane (8d)
1
Yield 69%; Colorless glassy solid; [α]D –18.5 (c 1, CHCl3); H NMR
(
400 MHz, CDCl3) δ 9.36 (d, J = 1.4 Hz, 1H, Ar-H), 8.77 (d, J = 2.4 Hz, 1H,
Ar-H), 8.56 (dd, J = 1.5 Hz, J = 2.3 Hz, 1H, Ar-H), 8.12 (s, 1H, -CONH-
\
ꢁ
), 5.38 (dd, J
ꢁ
ꢁ
= 0.88, J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.19 (dd, J
ꢁ ꢁ
1 ,2
= 7.9 Hz,
4
,5
3 ,4
ꢁ
J
3
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 4.99 (dd, J
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ ꢁ
2 ,3
= 10.5 Hz, 1H, H-
2
ꢁ
,3
3 ,4
ꢁ
), 4.50 (d, J
ꢁ
ꢁ
,2
= 7.9 Hz, 1H, H-1 ), 4.32, 3.92 (2 × d, J = 11.9 Hz, 2H,
1
C-CH2O-), 4.28, 4.11 (2 × d, J = 10.1 Hz, 2H, C-CH2O-), 4.26, 3.98 (2 × d,
ꢁ
J = 11.8 Hz, 2H, C-CH2O-), 4.14 (d, J
ꢁ
ꢁ
,6
= 6.6 Hz, 2H, H-6 a, b), 3.92–3.89
5
ꢁ
(
1
1
(
6
5
3
m, J
ꢁ
ꢁ
,5
= 0.88 Hz, 1H, H-5 ), 2.14, 2.05, 1.96, 1.92 (4 × s, 12H, 4 × -COCH3),
4
1
3
.49, 1.45 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz, CDCl3) δ 170.41, 170.20,
70.06, 169.33 (4 × -COCH3), 163.23 (-NHCO-), 147.43, 144.13, 144.44, 142.48
ꢁ
ꢁ
ꢁ
4 × Ar-C), 101.60 (C-1 ), 98.70 (C-2), 70.83 (C-5 ), 70.69 (C-3 ), 69.00 (-CH2O-),
ꢁ
ꢁ
ꢁ
8.77 (C-2 ), 66.96 (C-4 ), 63.01, 62.18 (C-4 and C-6), 61.14 (C-6 ), 53.36 (C-
), 24.73, 22.44 (-C(CH3)2), 20.68, 20.60, 20.55 (4 × -COCH3); IR (Neat) νmax
−1
386, 1750, 1678, 1528, 1371, 1222, 1076, 1046 cm ; HRMS: m/z calculated
for C26H35N3NaO13: 620.2068. Found: 620.2071.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-{(S)-3-
tert-butoxy-carbonyl)-1H-indol-3-yl)-2-(tert-butoxycarbonylamino)
propanamido}]-2,2-dimethyl-1,3-dioxane (8e)
Yield 71%; Colorless glassy solid; [α]D –4.2 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 8.47 (s, 1H, -CONH-), 7.73 (d, J = 7.4 Hz, 1H, Ar-H), 7.38
J = 8 Hz, 1H, Ar-H), 7.22–7.12 (m, 3H, Ar-H), 5.82 (s, 1H, -CONH-), 5.30
(
1
(

64 G. Mugunthan et al.
5
ꢁ
ꢁ
(
J3
4
3
brs, 1H, H-4 ), 5.13 (dd, J1
ꢁ
ꢁ
= 7.9 Hz, J
ꢁ ꢁ
2 ,3
= 10.4 Hz, 1H, H-2 ), 4.95 (dd,
,2
ꢁ
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ ꢁ
= 10.4 Hz, 1H, H-3 ), 4.42 (br s, 1H, -CH-(tryptophan)),
,4
2 ,3
ꢁ
ꢁ
.27 (d, J1
ꢁ
ꢁ
= 7.9 Hz, 1H, H-1 ), 4.13–3.62 (3 × m, 8H, H-6 a, b, 3 × -CH2O-),
,2
ꢁ
.58 (brs, 1H, H-5 ), 3.28, 3.16 (2 × dd, J = 8 Hz, J = 14 Hz, 2H, -CH2- (trypto-
phan)), 2.12, 2.09, 2.02, 2.00 (4 × s, 12H, 4 × -COCH3), 1.64, 1.44 (2 × s, 18H,
1
3
2
× -C(CH3)3), 1.37, 1.38 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz, CDCl3)
δ 171.89 (-NHCO-), 170.49, 170.16, 169.77 (4 × -COCH3), 155.23, 151.47 (2 ×
-
1
NHCO-), 136.20, 127.52, 123.41, 122.35, 119.77, 119.03, 111.29 (8 × Ar-C),
ꢁ
ꢁ
ꢁ
01.52 (C-1 ), 98.56 (C-2), 84.36 (-C(CH3)3), 70.66 (C-5 and C-3 ), 69.02 (-CH2-
ꢁ
ꢁ
O-), 68.88 (C-2 ), 67.12 (C-4 ), 62.52, 62.13, 61.43 (3 × -CH2O-), 53.20 (C-5),
2
2
8.55 (-CH2-), 28.32 (-CO(CH3)3), 23.67, 23.32 (-C(CH3)2), 20.73, 20.69, 20.62,
0.60 (4 × -COCH3); HRMS: m/z calculated for C42H59N3NaO17: 900.3742.
Found: 900.3740.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-{(S)-3-(1-
(
tert-butoxycarbonyl)-1H-imidazol-4-yl)-2-(tert-butoxycarbonylamino)
propanamido}]-2,2-dimethyl-1,3-dioxane (8f)
◦
Yield 68%; mp 69–73 C (crystallised from methanol); [α]D +8.7 (c 1,
1
CHCl3); H NMR (400 MHz, CDCl3) δ 8.02 (d, J = 1 Hz, 1H, Ar-H), 7.18
(
5
J
3
s, 1H, Ar-H), 6.96 (s, 1H, -CONH-), 5.93 (d, J = 5.2 Hz, 1H, -CH-NH-CO-),
ꢁ
.38 (dd, J4
ꢁ
ꢁ
= 0.8 Hz, J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.16 (dd, J
ꢁ ꢁ
1 ,2
= 7.8 Hz,
,5
3 ,4
ꢁ
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 5.02 (dd, J
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ ꢁ
2 ,3
= 10.5 Hz, 1H, H-
2
ꢁ
,3
3 ,4
ꢁ
), 4.45 (d, J1
ꢁ
ꢁ
ꢁ
= 7.8 Hz, 1H, H-1 ), 4.36 (m, 1H, -NH-CH-CH2), 4.14 (d,
,2
ꢁ
J5
ꢁ
= 6.6 Hz, 2H, H-6 a, b), 4.09, 3.94 (2 × d, J = 10 Hz, 2H, C-CH2O-), 4.07,
,6
ꢁ
3
3
1
.76 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 3.91–3.85 (m, 3H, H-5 and -CH2O-),
.02–2.91 (m, 2H, -CH2-), 2.18, 2 × 2.07, 1.98 (4 × s, 12H, 4 × -COCH3), 1.59,
1
3
.43 (2 × s, 18H, 2 × -C(CH3)3), 1.36 (s, 6H, -C(CH3)2); C NMR (100 MHz,
CDCl3) δ 170.41, 170.26, 170.05, 169.52 (4 × -COCH3), 150.34, 146.90 (-CONH-
ꢁ
)
, 138.92, 136.86, 114.75 (3 × Ar-C), 101.46 (C-1 ), 98.33 (C-2), 85.48, 80.05 (2
ꢁ
ꢁ
ꢁ
×
-C(CH3)3), 70.80 (C-5 ), 70.67 (C-3 ), 68.92 (-CH2O-), 68.84 (C-2 ), 67.01 (C-
ꢁ
ꢁ
4
), 62.47, 62.35 (C-4 and C-6), 61.21 (C-6 ), 53.05 (C-5), 30.75 (-CH2-), 28.28,
2
7.85 (2 × -C(CH3)3), 24.96, 22.38 (-C(CH3)2) 20.75, 20.68, 20.66, 20.56 (4 ×
-
COCH3); IR (Neat) νmax 3330, 2981, 2927, 1752, 1714, 1671, 1496, 1389, 1371,
−1
1
8
248, 1225, 1157, 1052, 1012 cm ; HRMS: m/z calculated for C37H56N4NaO17:
51.3538. Found: 851.3531.
General Procedure for Amide Bond Formation Using Acid
Chloride and Amine
To a solution of the amine (7, 1 mmol) and DIPEA (1 mmol) in anhydrous
DMF (5 mL) maintained over an ice bath was added a solution of the acid
chloride (1 mmol) in anhydrous DMF (5 mL) dropwise. After 30 min, the sol-
vent was evaporated off under reduced pressure and the crude product was

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
65
subjected to chromatographic purification on a column of silica gel to yield the
respective product in pure form.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-
(
2-chloro-pyridine-3-carboximido)]-2,2-dimethyl-1,3-dioxane (8g)
1
Yield 90%; Colorless foam; [α]D –8.3 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 8.47 (dd, J = 2.0 Hz, J = 4.7 Hz, 1H, Ar-H), 8.04 (dd, J = 2.0 Hz,
J = 7.6 Hz, 1H, Ar-H), 7.35 (dd, J = 4.7 Hz, J = 7.6 Hz, 1H, Ar-H), 6.77
ꢁ
(
(
J2
s, 1H, -CONH-), 5.38 (dd, J4
ꢁ
ꢁ
= 0.9 Hz, J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.19
,5
3 ,4
ꢁ
dd, J1
ꢁ
ꢁ
= 7.8 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 5.01 (dd, J
ꢁ ꢁ
3 ,4
= 3.4 Hz,
,2
2 ,3
ꢁ
ꢁ
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.52 (d, J
ꢁ ꢁ
1 ,2
= 7.8 Hz, 1H, H-1 ), 4.42, 3.84 (2 ×
,3
d, J = 11.9 Hz, 2H, C-CH2O-), 4.27, 4.05 (2 × d, J = 10.0 Hz, 2H, C-CH2O-),
.25, 3.95 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.07 (d, J = 6.5 Hz, 2H,
4
ꢁ
ꢁ
,6
5
ꢁ
ꢁ
H-6 a, b), 3.90 (dt, J
1
(
(
9
6
2
1
ꢁ
ꢁ
= 0.9 Hz, J
ꢁ ꢁ
5 ,6
= 6.5 Hz, 1H, H-5 ), 2.16, 2.04, 1.99,
13
4
,5
.98 (4 × s, 12H, 4 × -COCH3), 1.51, 1.45 (2 × s, 6H, -C(CH3)2); C NMR
100 MHz, CDCl3) δ 170.37, 170.22, 170.09, 169.49 (4 × -COCH3), 165.07
ꢁ
-NHCO-), 151.06, 147.12, 139.20, 131.48, 122.67 (5 × Ar-C), 101.33 (C-1 ),
ꢁ
ꢁ
ꢁ
ꢁ
8.74 (C-2), 70.84 (C-5 ), 70.63 (C-3 ), 69.00 (-CH2O-), 68.78 (C-2 ), 66.89 (C-4 ),
ꢁ
2.74, 61.85 (C-4 and C-6), 61.08 (C-6 ), 54.10 (C-5), 24.48, 22.75 (-C(CH3)2),
0.74, 20.69, 20.57 (4 × -COCH3); IR (Neat) νmax 3328, 2991, 2934, 2869, 1749,
−
1
668, 1582, 1541, 1400, 1371, 1223, 1075 cm ; HRMS: m/z calculated for
C27H35ClN2NaO13: 653.1725. Found: 653.1732.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-
5
-[N-(quinoline-2-carboximido)]-2,2-dimethyl-1,3-dioxane (8h)
1
Yield 92%; Colorless foam; [α]D –29.1 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 8.56 (s, 1H, -CONH-), 8.32, 8.24, 8.16 (3 × d, J = 8.5 Hz, 3H, Ar-
H), 7.88 (d, J = 7.6 Hz, 1H, Ar-H), 7.78 (dt, J1 = 6.9 Hz, J2 = 1.36 Hz, 1H,
Ar-H), 7.64 (dt, J1 = 6.9 Hz, J2 = 1 Hz, 1H, Ar-H), 5.37 (dd, J
ꢁ
ꢁ
,5
= 0.9 Hz,
4
ꢁ
ꢁ
J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.22 (dd, J
ꢁ
ꢁ
= 7.9 Hz, J
ꢁ ꢁ
2 ,3
= 10.5 Hz, 1H, H-2 ), 4.98
3
,4
1 ,2
ꢁ
ꢁ
(
4
dd, J
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.53 (d, J
ꢁ ꢁ
1 ,2
= 7.9 Hz, 1H, H-1 ),
3
,4
2 ,3
.35, 4.01 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.31, 4.20 (2 × d, J = 10.2 Hz, 2H,
= 6.6 Hz,
C-CH2O-), 4.29, 4.04 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.13 (d, J
ꢁ
ꢁ
,6
5
ꢁ
ꢁ
2
1
H, H-6 a, b), 3.90 (dt, J
ꢁ
ꢁ
= 0.88 Hz, J
ꢁ ꢁ
5 ,6
= 6.6 Hz, 1H, H-5 ), 2.13, 2.05,
13
4
,5
.94, 1.81 (4 × s, 12H, 4 × -COCH3), 1.51, 1.47 (2 × s, 6H, -C(CH3)2); C NMR
(
100 MHz, CDCl3) δ 170.39, 170.24, 170.07, 169.43 (4 × -COCH3), 164.72 (-
NHCO-), 149.60, 146.38, 137.60, 130.20, 129.83, 129.32, 128.05, 127.70, 118.31
ꢁ
ꢁ
ꢁ
(
9 × Ar-C), 101.78 (C-1 ), 98.69 (C-2), 70.78 (C-5 ), 70.72 (C-3 ), 69.10 (-CH2O-),
ꢁ
ꢁ
ꢁ
6
2
3
8.78 (C-2 ), 67.03 (C-4 ), 63.29, 62.46 (C-4 and C-6), 61.23 (C-6 ), 53.29 (C-5),
4.43, 22.83 (-C(CH3)2), 20.68, 20.64, 20.54, 20.49 (4 × -COCH3); IR (Neat) νmax
−1
369, 2985, 2942, 2869, 1750, 1676, 1525, 1501, 1371, 1221, 1076, 1049 cm ;
HRMS: m/z calculated for C31H38N2NaO13: 669.2272. Found: 669.2261.

66 G. Mugunthan et al.
5
General Procedure for the Synthesis of Urea and Thiourea
Derivatives
Amine 7 (1 mmol) was stirred with the desired aryl isocyanate
(ArNCO)/aryl isothiocyanate (ArNCS) in anhydrous DMF for 1 to 2 h at rt.
After completion of the reaction, the solvent was evaporated off under re-
duced pressure and the residue was subjected to chromatographic purification
to yield the respective desired product.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-
5
-[N-(furfuryl urea)]-2,2-dimethyl-1,3-dioxane (9a)
1
Yield 82%; Colorless glassy solid; [α]D –7.0 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 7.35 (dd, J3
ꢁ
ꢁ
ꢁ
= 0.6 Hz, J
ꢁ ꢁ
= 1.8 Hz, 1H, Ar-H-3 ), 6.32 (dd,
,5
3 ,4
ꢁ
J3
ꢁ
ꢁ
= 1.8 Hz, J
ꢁ
ꢁ
= 3.1 Hz, 1H, Ar-H-4 ), 6.22 (d, J
ꢁ ꢁ
4 ,5
= 3.1 Hz, 1H, Ar-
,4
4 ,5
ꢁ
ꢁ
H-5 ), 5.38 (dd, J
ꢁ
ꢁ
= 0.9, J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.16 (dd, J
ꢁ ꢁ
1 ,2
= 7.9 Hz,
= 3.4 Hz,
4
,5
3 ,4
ꢁ
J2
J2
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 5.03 (s, 1H, -CONH-), 5.00 (dd, J
ꢁ
ꢁ
,3
3 ,4
ꢁ
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.85 (s, 1H, -CONH-), 4.46 (d, J
ꢁ
ꢁ
= 7.9 Hz, 1H,
,3
1 ,2
ꢁ
H-1 ), 4.36, 3.68 (2 × d, J = 12.3 Hz, 2H, C-CH2O-), 4.33 (dd, J = 6 Hz,
J = 12 Hz, 2H, -CH2-Ar), 4.18, 3.76 (2 × d, J = 11.7 Hz, 2H, C-CH2O-), 4.16 (d,
ꢁ
J
ꢁ
ꢁ
,6
= 6.6 Hz, 2H, H-6 a,b), 4.11, 3.92 (2 × d, J = 10 Hz, 2H, C-CH2O-), 3.86
5
ꢁ
(
4
dt, J4
ꢁ
ꢁ
= 0.9 Hz, J
ꢁ ꢁ
5 ,6
= 6.6 Hz, 1H, H-5 ), 2.15, 2.05, 2.04, 1.98 (4 × s, 12H,
,5
1
3
× -COCH3), 1.49, 1.38 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz, CDCl3)
δ 170.49, 170.20, 170.04, 170.00 (4 × -COCH3), 156.95 (-HNCONH-), 152.22,
ꢁ
ꢁ
1
(
6
2
1
6
42.04, 110.43, 107.01 (4 × Ar-C), 101.69 (C-1 ), 98.60 (C-2), 70.92 (C-5 ), 70.75
ꢁ
ꢁ
ꢁ
-CH2O-), 70.57 (C-3 ), 69.01 (C-2 ), 67.04 (C-4 ), 63.29, 62.44 (C-4 and C-6),
ꢁ
1.38 (C-6 ), 52.32 (C-5), 37.18 (NH-CH2-Ar), 24.52, 22.79 (-C(CH3)2), 20.77,
0.65, 20.55 (4 × -COCH3); IR (Neat) νmax 3400, 2978, 2927, 2869, 1749, 1656,
−1
558, 1371, 1223, 1076, 1049 cm ; HRMS: m/z calculated for C27H38N2NaO14:
37.2221. Found: 637.2243.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-
5
-[N-(4-nitro phenylurea)]-2,2-dimethyl-1,3-dioxane (9b)
1
Yield 91%; Glassy yellow solid; [α]D –19.6 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 8.14, 7.52 (2 × d, J = 9.2 Hz, 4H, Ar-H), 7.95 (s, 1H, -CONH-),
ꢁ
5
.50 (s, 1H, -CONH-), 5.41 (dd, J4
ꢁ
ꢁ
= 0.9, J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.17
,5
3 ,4
ꢁ
(dd, J1
ꢁ
ꢁ
= 7.8 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 5.03 (dd, J
ꢁ ꢁ
3 ,4
= 3.4 Hz,
,2
2 ,3
ꢁ
ꢁ
J2
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.50 (d, J
ꢁ ꢁ
1 ,2
= 7.8 Hz, 1H, H-1 ), 4.47, 3.70 (2 ×
,3
d, J = 11.8 Hz, 2H, C-CH2O-), 4.34, 3.82 (2 × d, J = 11.7 Hz, 2H, C-CH2O- ),
ꢁ
4
(
.31, 4.09 (2 × dd, J
ꢁ
ꢁ
= 6.6 Hz, J
ꢁ ꢁ
6 a,6 b
= 11.4 Hz, 2H, H-6 a,b), 4.15, 3.91
5
,6
2 × d, J = 9.8 Hz, 2H, C-CH2O-), 3.92 (dt, J
ꢁ
ꢁ
= 0.9, J
ꢁ ꢁ
5 ,6
= 6.6 Hz, 1H,
4
,5
ꢁ
H-5 ), 2.16, 2.07, 2.05, 1.99 (4 × s, 12H, 4 × -COCH3), 1.54, 1.43 (2 × s, 6H,
1
3
-
C(CH3)2); C NMR (100 MHz, CDCl3) δ 170.90, 170.32, 170.13, 170.01 (4 ×

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
67
-
COCH3), 162.79 (-NHCONH-), 153.82, 145.62, 142.12, 125.20, 117.55 (6 × Ar-
ꢁ
ꢁ
ꢁ
C), 101.37 (C-1 ), 98.78 (C-2), 71.22 (C-5 ), 70.47 (C-3 ), 70.20 (-CH2O-), 69.08
(
ꢁ
ꢁ
ꢁ
C-2 ), 67.03 (C-4 ), 62.91, 62.07 (C-4 and C-6), 61.39 (C-6 ), 52.48 (C-5), 24.54,
2
2.81 (-C(CH3)2), 20.91, 20.78, 20.66, 20.56 (4 × -COCH3); IR (Neat) νmax 3380,
−1
2992, 2905, 2876, 1750, 1707, 1544, 1507, 1371, 1330, 1228, 1052 cm ; HRMS:
m/z calculated for C28H37N3NaO15: 678.2122. Found: 678.2147.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-
-[N-(4-chloro phenylurea)]-2,2-dimethyl-1,3-dioxane (9c)
Yield 85%; Colorless glassy solid; [α]D –16.0 (c 1, CHCl3); 1H NMR
5
(
J
2
J1
3
J
(
4
400 MHz, CDCl3) δ 7.30–7.22 (m, 4H, Ar-H), 6.98 (s, 1H, -CONH-), 5.40 (dd,
ꢁ
ꢁ
ꢁ
= 0.9, J
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.20–5.15 (m, J
ꢁ ꢁ
= 7.8 Hz, 2H, H-
4
,5
3 ,4
1 ,2
ꢁ
ꢁ
, -CONH-), 5.03 (dd, J
ꢁ
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ ꢁ
2 ,3
= 10.4 Hz, 1H, H-3 ), 4.49 (d,
3
,4
ꢁ
ꢁ
= 7.8 Hz, 1H, H-1 ), 4.44, 3.69 (2 × d, J = 11.8 Hz, 2H, -C-CH2-O-), 4.29,
,2
.79 (2 × d, J = 11.7 Hz, 2H, C-CH2O-), 4.25, 4.11 (2 × dd, J
ꢁ
ꢁ
,6
= 6.6 Hz,
5
ꢁ
ꢁ
ꢁ
a,6 b
= 11.4 Hz, 2H, H-6 a, b), 4.14, 3.92 (2 × d, J = 10 Hz, 2H, C-CH2O-), 3.91
6
ꢁ
dt, J4
ꢁ
ꢁ
= 0.92 Hz, J
ꢁ ꢁ
5 ,6
= 6.6 Hz, 1H, H-5 ), 2.16, 2.06, 2.05, 1.99 (4 × s, 12H,
,5
1
3
× -COCH3), 1.49, 1.38 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz, CDCl3)
δ 170.66, 170.21, 170.17, 170.02 (4 × -COCH3), 154.61(-NHCONH-), 137.41,
ꢁ
ꢁ
1
(
6
-
29.00, 128.07, 120.87 (4 × Ar-C), 101.47 (C-1 ), 98.76 (C-2), 71.06 (C-5 ), 70.51
ꢁ
ꢁ
ꢁ
C-3 ), 70.33 (-CH2O-), 69.07 (C-2 ), 67.00 (C-4) , 63.15, 62.35 (C-4 and C-6),
ꢁ
1.31 (C-6 ), 52.40 (C-5), 24.17, 23.16 (-C(CH3)2), 20.86, 20.72, 20.63, 20.55 (4 ×
COCH3); IR (Neat) νmax 3388, 2991, 2934, 2884, 1751, 1699, 1541, 1493, 1371,
−1
1
226, 1077, 1049 cm ; HRMS: m/z calculated for C28H37ClN2NaO13: 667.1882.
Found: 667.1891.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-
-[N-(3-cyano phenylurea)]-2,2-dimethyl-1,3-dioxane (9d)
Yield 88%; Colorless glassy solid; [α]D –17.5 (c 1, CHCl3); H NMR
5
1
(
400 MHz, CDCl3) δ 7.73 (s, 1H, Ar-H), 7.56, 7.27 (2 × d, J = 8 Hz, 2H, Ar-
H), 7.40 (s, 1H, -CONH-), 7.35 (t, J = 8 Hz, 1H, Ar-H), 5.41 (dd, J
ꢁ
ꢁ
,5
= 0.84,
4
ꢁ
ꢁ
J
J
3
1
ꢁ
ꢁ
ꢁ
ꢁ
= 3.4 Hz, 1H, H-4 ), 5.25 (s, 1H, -CONH-), 5.18 (dd, J
ꢁ ꢁ
1 ,2
= 7.8 Hz,
3
,4
,3
= 10.5 Hz, 1H, H-2 ), 5.04 (dd, J
ꢁ
ꢁ
= 3.4 Hz, J
ꢁ ꢁ
2 ,3
= 10.5 Hz, 1H, H-
2
ꢁ
3 ,4
), 4.53, 3.66 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.50 (d, J
ꢁ
ꢁ
,2
= 7.8 Hz,
1
ꢁ
H, H-1 ), 4.37, 3.78 (2 × d, J = 11.6 Hz, 2H, C-CH2O-), 4.32, 4.09 (2 ×
ꢁ
dd, J
ꢁ
ꢁ
= 6.6 Hz, J
ꢁ ꢁ
6 a,6 b
= 11.4 Hz, 2H, H-6 a, b), 4.14, 3.91 (2 × d,
5
,6
ꢁ
J = 10 Hz, 2H, C-CH2O-), 3.91 (pt, J
ꢁ
ꢁ
,6
= 6.6 Hz, 1H, H-5 ), 2.18, 2.07,
5
1
3
2
.06, 2.00 (4 × s, 12H, 4 × -COCH3), 1.56, 1.42 (2 × s, 6H, -C(CH3)2); C
NMR (100 MHz, CDCl3) δ 170.84, 170.39, 170.14, 170.00 (4 × -COCH3),
1
54.17 (-NHCONH-), 140.00, 129.72, 126.07, 122.96, 121.81 (5 × Ar-C), 118.74
ꢁ
ꢁ
ꢁ
(-CN), 112.84 (Ar-C), 101.34 (C-1 ), 98.85 (C-2), 71.21 (C-5 ), 70.44 (C-3 ),
ꢁ
ꢁ
7
(
0.29 (-CH2O-), 69.13 (C-2 ), 67.01 (C-4 ), 62.89, 62.09 (C-4 and C-6), 61.37
ꢁ
C-6 ), 52.40 (C-5), 24.79, 22.55 (-C(CH3)2), 20.93, 20.76, 20.64, 20.55 (4 ×

68 G. Mugunthan et al.
5
-
1
6
COCH3); IR (Neat) νmax 3388, 2985, 2927, 2869, 1749, 1696, 1548, 1371, 1226,
076, 1053 cm ; HRMS: m/z calculated for C29H37N3NaO13: 658.2224. Found:
58.2219.
−1
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-
(
3,5-di-trifluoromethyl phenylurea)]-2,2-dimethyl-1,3-dioxane (9e)
1
Yield 84%; Colorless foam; [α]D –14.0 (c 1, CHCl3); H NMR (400 MHz,
CDCl3) δ 7.84 (s, 2H, Ar-H), 7.69 (s, 1H, Ar-H), 7.47 (s, 1H, -CONH-), 5.41
ꢁ
(
dd, J4
ꢁ
ꢁ
= 0.92, J
ꢁ ꢁ
= 3.4 Hz, 1H, H-4 ), 5.33 (s, 1H, -CONH-), 5.18
,5
3 ,4
ꢁ
(dd, J1
ꢁ
ꢁ
= 7.8 Hz, J
ꢁ
ꢁ
= 10.5 Hz, 1H, H-2 ), 5.04 (dd, J
ꢁ ꢁ
3 ,4
= 3.4 Hz,
,2
2 ,3
ꢁ
J2
(
4
ꢁ
ꢁ
= 10.5 Hz, 1H, H-3 ), 4.54, 3.69 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.50
,3
ꢁ
d, J1
ꢁ
ꢁ
= 7.8 Hz, 1H, H-1 ), 4.37, 3.81 (2 × d, J = 11.8 Hz, 2H, C-CH2O-), 4.33,
,2
ꢁ
.08 (2 × dd, J
ꢁ
ꢁ
= 6.6 Hz, J
ꢁ ꢁ
6 a,6 b
= 11.5 Hz, 2H, H-6 a,b), 4.12, 3.92 (2 × d,
5
,6
ꢁ
J = 10 Hz, 2H, C-CH2O-), 3.93–3.90 (m, 1H, H-5 ), 2.16, 2 × 2.07, 2.00, (4 ×
1
3
s, 12H, 4 × -COCH3), 1.56, 1.43 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz,
CDCl3) δ 170.97, 170.47, 170.15, 170.01 (4 × -COCH3), 153.91 (-NHCONH-),
1
(
6
40.73, 132.30 (3 × Ar-C), 131.97 (Ar-C), 124.73 (2 × -CF3), 118.20, 115.65
ꢁ
ꢁ
ꢁ
2 × Ar-C), 101.26 (C-1 ), 98.91 (C-2), 71.29 (C-5 ), 70.44 (C-3 ), 70.24 (-CH2O-),
ꢁ
ꢁ
ꢁ
9.15 (C-2 ), 67.02 (C-4 ), 62.78, 62.14 (C-4 and C-6), 61.45 (C-6 ), 52.49 (C-5),
2
4.45, 22.51 (-C(CH3)2), 20.96, 20.77, 20.65, 20.56 (4 × -COCH3); IR (Neat)
νmax 3383, 2949, 2985, 2884, 1754, 1707, 1557, 1474, 1386, 1279, 1227, 1178,
−1
1132, 1076 cm ; HRMS: m/z calculated for C30H36F6N2NaO13: 769.2019.
Found: 769.2015.
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-
2,6-di-dichloro phenylthiourea)]-2,2-dimethyl-1,3-dioxane (10a)
Yield 76%; Colorless glassy solid; [α]D –12.6 (c 1, CHCl3); 1H NMR
(
(
400 MHz, CDCl3) δ 7.42 (d, J = 8.1 Hz, 1H, Ar-H), 7.25 (t, J = 8.1 Hz, 1H,
ꢁ
Ar-H), 6.65 (s, 1H, -CONH-), 5.40 (dd, J
5
J2
5
ꢁ
ꢁ
= 1.0 Hz, J
ꢁ ꢁ
3 ,4
= 3.4 Hz, 1H, H-4 ),
4
,5
ꢁ
.18 (dd, J1
ꢁ
ꢁ
= 8 Hz, J
ꢁ
ꢁ
= 10.4 Hz, 1H, H-2 ), 5.03 (dd, J
ꢁ ꢁ
3 ,4
= 3.4 Hz,
,2
2 ,3
ꢁ
ꢁ
ꢁ
ꢁ
= 10.4 Hz, 1H, H-3 ), 4.54 (d, J
ꢁ ꢁ
1 ,2
= 8 Hz, 1H, H-1 ), 4.24–4.13 (m,
,3
ꢁ
H, H-6 a, b, and 3H from C-CH2O-), 4.02 (d, J = 9.7 Hz, 1H, from C-
ꢁ
CH2O-), 3.95 (dt, J5
ꢁ
ꢁ
= 6.6 Hz, J
ꢁ ꢁ
4 ,5
= 1.0 1H, H-5 ), 3.84, 3.79 (2 × d,
,6
J = 12.6 Hz, 2H, from C-CH2O-), 2.18, 2.11, 2.06, 1.98 (4 × s, 12H, 4 × -
1
3
COCH3), 1.41, 1.37 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz, CDCl3) δ 177.95
(
-HNCSNH-), 170.43, 170.22, 170.09, 169.73 (4 × -COCH3), 135.46, 129.38,
ꢁ
1
5
4
28.56, 127.75, 120.04, 119.82 (6 × Ar-C) 101.05 (C-1 ), 99.34 (C-2), 71.03 (C-
ꢁ
ꢁ
ꢁ
ꢁ
), 70.58 (C-3 ), 69.46 (-CH2O-), 68.52 (C-2 ), 66.86 (C-4 ), 62.90, 61.68 (C-
ꢁ
and C-6), 61.18 (C-6 ), 24.06, 22.65 (-C(CH3)2), 20.87, 20.71, 20.69, 20.56
(
1
6
4 × -COCH3); IR (Neat) νmax 3347, 2985, 2934, 2876, 1749, 1371, 1222, 1075,
−1
049 cm ; HRMS: m/z calculated for C28H36Cl2N2NaO12S: 694.1366. Found:
94.1342.

Potential Mimic of UDP-Gal p against M. Tuberculosis
5
69
ꢁ
ꢁ
ꢁ
ꢁ
5
-[O-(2 ,3 ,4 ,6 -Tetra-O-acetyl-β-D-galactopyranosyl)oxymethyl]-5-[N-(2-bromo-
-fluoro phenylthiourea)]-2,2-dimethyl-1,3-dioxane (10b)
Yield 79%; Colorless glassy solid; [α]D –20.3 (c 1, CHCl3); H NMR
6
1
(
400 MHz, CDCl3) δ 7.62 (t, J = 8.2 Hz, 1H, Ar-H), 7.34 (d, J = 8.2 Hz, 1H,
ꢁ
Ar-H), 6.59 (s, 1H, -CONH-), 5.40 (dd, J4
5
J2
ꢁ
ꢁ
= 1.0 Hz, J
ꢁ ꢁ
3 ,4
= 3.4 Hz, 1H, H-4 ),
,5
ꢁ
.21 (dd, J1
ꢁ
ꢁ
= 7.9 Hz, J
ꢁ
ꢁ
= 10.4 Hz, 1H, H-2 ), 5.02 (dd, J
ꢁ ꢁ
3 ,4
= 3.4 Hz,
,2
2 ,3
ꢁ
ꢁ
ꢁ
ꢁ
= 10.4 Hz, 1H, H-3 ), 4.56 (d, J
ꢁ ꢁ
1 ,2
= 8 Hz, 1H, H-1 ), 4.24–4.11 (m, 5H,
,3
ꢁ
H-6 a, b and 3H from C-CH2O-), 4.02 (d, J = 9.8 Hz, 1H, from C-CH2O-), 3.95
ꢁ
(
dt, J
ꢁ
ꢁ
= 1.0 Hz, J
ꢁ ꢁ
5 ,6
= 6.6 Hz, 1H, H-5 ), 3.81, 3.78 (2 × d, J = 12.6 Hz,
4
,5
2
1
1
(
6
H, from C-CH2O-), 2.17, 2.08, 2.06, 1.99 (4 × s, 12H, 4 × -COCH3), 1.43,
13
.40 (2 × s, 6H, -C(CH3)2); C NMR (100 MHz, CDCl3) δ 178.21 (-HNCSNH-)
70.46, 170.21, 170.08, 169.81 (4 × -COCH3), 133.92, 127.73, 120.04, 119.81
ꢁ
ꢁ
ꢁ
ꢁ
6 × Ar-C), 101.10 (C-1 ), 98.65 (C-2), 71.02 (C-5 ), 70.56 (C-3 ), 68.49 (-CH2O-),
ꢁ
ꢁ
8.51 (C-2 ) 66.84 (C-4 ), 62.90, 61.65 (C-4 and C-6), 61.17 (C-6 ), 24.12, 22.65
(
2
-C(CH3)2), 20.82, 20.74, 20.71, 20.58 (4 × -COCH3); IR (Neat) νmax 3353, 2991,
−1
927, 2884, 1750, 1536, 1494, 1371, 1224, 1075, 1046 cm ; HRMS: m/z calcu-
lated for C28H36BrFN2NaO12S: 745.1054. Found: 745.1060.
ACKNOWLEDGEMENT
M.G. sincerely acknowledges financial support in the form of a Senior Research
Fellowship by NIPER.
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1
.
MDR and XDR-TB progress report 2011 - fact sheet. Available at: http://www.who.
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2
. Weston, A.; Stern, R.J.; Lee, R.E.; Nassau, P.M.; Monsey, D.; Martin, S.L.;
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terial cell wall galactofuranosyl residues. Tuber. Lung Dis. 1998, 78, 123–131.
3
.
Pederson, L.L.; Turco, S.J. Galactofuranose metabolism: a potential target for an-
timicrobial chemotherapy. Cell. Mol. Life Sci. 2003, 60, 259–266.
4
.
Richards, M.R.; Lowry, T.L. Chemistry and biology of galactofuranose-containing
polysaccharides. ChemBioChem 2009, 10, 1920–1938.
5
.
Lowry, T.L. Recent progress towards the identification of inhibitors of mycobacte-
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