Synthesis and evaluation of antimicrobial activity of some pyrimidine glycosides

Article abstract of DOI:10.1080/15257770802271805

Reaction of ethyl 4-thioxo-3,4-dihydropyrimidine-5-carboxylate derivatives 1a,b and ethyl 4-oxo-3,4-dihydropyrimidine-5-carboxylate 1c with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide in KOH or TEA afforded ethyl 2-aryl-4-(2′,3′,4′,6′-tetra-O-acetyl

Full text of DOI:10.1080/15257770802271805

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Synthesis and Evaluation of
Antimicrobial Activity of Some
Pyrimidine Glycosides
H. A. El-Sayed a , A. H. Moustafa a , A. Z. Haikal a , I. M. Abdou b &
E. S. H. El-Ashry c
a Department of Chemistry, Faculty of Science, Zagazig Univeristy,
Zagazig, Egypt
b Department of Chemistry, Faculty of Science, United Arab Emirates
University, United Arab Emirates
c Department of Chemistry, Faculty of Science, Alexandria
University, Alexandria, Egypt
Version of record first published: 18 Aug 2008.
To cite this article: H. A. El-Sayed , A. H. Moustafa , A. Z. Haikal , I. M. Abdou & E. S. H. El-Ashry
(2008): Synthesis and Evaluation of Antimicrobial Activity of Some Pyrimidine Glycosides, Nucleosides,
Nucleotides and Nucleic Acids, 27:9, 1061-1071
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Nucleosides, Nucleotides and Nucleic Acids, 27:1061–1071, 2008
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1525-7770 print / 1532-2335 online
DOI: 10.1080/15257770802271805
SYNTHESIS AND EVALUATION OF ANTIMICROBIAL ACTIVITY
OF SOME PYRIMIDINE GLYCOSIDES
H. A. El-Sayed,1 A. H. Moustafa,1 A. Z. Haikal,1 I. M. Abdou,2 and
E. S. H. El-Ashry3
1Department of Chemistry, Faculty of Science, Zagazig Univeristy, Zagazig, Egypt
2Department of Chemistry, Faculty of Science,
United Arab Emirates University, United Arab Emirates
3Department of Chemistry, Faculty of Science, Alexandria University, Alexandria, Egypt
Reaction of ethyl 4-thioxo-3,4-dihydropyrimidine-5-carboxylate derivatives 1a,b and ethyl 4-oxo-
2
3,4-dihydropyrimidine-5-carboxylate 1c with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide in
KOH or TEA afforded ethyl 2-aryl-4-(2ꢁ,3ꢁ,4ꢁ,6ꢁ-tetra-O-acetyl-β-D-glucopyranosylthio or/ oxy)-6-
methylpyrimidine-5-carboxylate 6a-c. The glucosides 6a and 6b were obtained by the reaction of
1a and 1b with peracetylated glucose3 under MW irradiation. Mercuration of 1a followed by
reaction with acetobromoglucose gave the same product 6a. The reaction of 1a-c with peracetylated
ribose 4 under MW irradiation gave ethyl 2-aryl-4-(2ꢁ,3ꢁ,5ꢁ-tri-O-acetyl-β-D-ribofuranosylthio)-6-
methylpyrimidine-5-carboxylate 8a–c. The deprotection of 6a–c and 8a–c in the presence of methanol
and TEA/H2O afforded the deprotected products 7a–c and 9a–c. The structure were confirmed by
using 1H and 13CNMR spectra. Selected members of these compounds were screened for antimicrobial
activity.
Keywords Pyrimidin-4-one or/thione; pyrimidine glycosides and/ribosides; antimicro-
bial activity
INTRODUCTION
Pyrimidines, being an integral part of DNA and RNA, play an essential
role in several biological processes and have considerable chemical and
pharmacological importance. The pyrimidine ring can be found in antiviral
nucleosides, antibiotics, antibacterials, antitumor, cardiovascular as well as
agrochemical, veterinary products and antimycobacterial agents.[1–6] Some
pyrimidine derivatives exhibit potent nanomolar activities against GSK-3β
Received 7 April 2008; accepted 22 May 2008.
Address correspondence to A. H. Moustafa, Department of Chemistry, Faculty of Science, Zagazig
Univeristy, Zagazig, Egypt. E-mail: ah hu mostafa@yahoo.com
1061

1062
H. A. El-Sayed et al.
kinase as well as in an NF-κβ reporter gene assay,[7] and anticancer activity
against the MCF-7 cell line.[8] There are pyrimidine acyclic nucleosides that
act as moderate viral replication inhibitors against HBV.[9]
Glycosylthio-heterocycles have attracted much attention because of their
abilities to function as biological inhibitors,[10–17] inducers, and ligands[18]
for affinity of chromatography of carbohydrate-process enzymes and pro-
teins. For these reasons we synthesized several pyrimidine glycosides for
evaluation of their biological activity.
RESULTS AND DISCUSSION
We report in this work the results of our investigation into the
utility of the reaction of previous reported pyrimidine[19,20] with α-halo
and peracetylated sugars, for the synthesis of some glucosides and
ribosides. Glucosides 6a and 6b could be obtained by the reaction of ethyl
2-aryl-4-mercapto-6-methyl-pyrimidine-5-carboxylate (1a) and (1b) with
2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (2) in the presence of
aqueous potassium hydroxide[4] in 50 and 69% yields, respectively. The
same glucosides 6a and 6b could be obtained in better yields by MW
irradiation of 1a and 1b with peracetylated glucose (3) for 30 seconds
using silica gel as a solid support.[21] On the other hand, glucoside 6a was
obtained in 15% yield by heating chloromercuric salt 5a of 1a with 2 in dry
xylene at reflux (Scheme 1).
CH3
CH3
CO2Et
X=S; aq.KOH/acetone,(2)
N
CO2Et
X
N
TEA/MeOH
H2O
or, MWI, 3
Ar
N
X
Ar
N
OH
OAc
O
O
OH
OAc
6a-c
HO
CH3
AcO
AcO
HO
CO2Et
X
7a-c
N
X=O;
TEA/MeCN, (2)
or,
K2CO3,Me2CO/DMF,(2)
Ar
N
H
xylene,reflux
1a-c
(2)
a; Ar = Ph, X = S
b; Ar = p.Cl-C6H4, X = S
c; Ar = p.Cl-C6H4, X = O
CH3
CO2Et
SHgCl
N
HgCl2/EtOH
aq.NaOH
Ar
N
5a
2 = acetobromoglucose
3 = peracetylated glucose
SCHEME 1

Antimicrobial Activity of Pyrimidine Glycosides
1063
1
The structure of 6a and 6b were confirmed by using IR, UV, H, and
1
13C NMR spectra. The H NMR spectra of 6a and 6b exhibited doublets at
ꢁ
ꢁ
ꢁ
δ 6.22 and 6.40 with (J 1 ,2 = 8.00 and 8.32 Hz), respectively, for the H-1
protons characteristic for β-configuration. The 13C NMR spectra revealed
the absence of signals for (C = S) group, the presence of signals at δ 165.8
and 167.0 for C-4 atoms, and signals at δ 79.1 and 79.9 for the anomeric
carbons, respectively.
Glucoside 6c was obtained by the reaction of ethyl 2-(4-chlorophenyl)-
4-oxo-6-methyl-3,4-dihydropyrimidine-5-carboxylate (1c) with glucosyl bro-
mide 2 at room temperature in presence of triethylamine.[22] On the other
hand, the same glucoside 6c was obtained in 53% yield in the presence of
1
acetone/DMF and potassium carbonate (Scheme 1). The H NMR spec-
trum of 6c showed the singlets at δ 1.89, 2.00, 2.01, and 2.04 characteristic
ꢁ
ꢁ
for the acetoxy groups of the sugar and a doublet at δ 6.21 (J 1 ,2 = 7.78
Hz) for the H-1ꢁ proton which is characteristic for the β-configuration. The
13C NMR spectrum of compound 6c showed four singlets at δ 20.4, 20.5,
20.9, and 22.6 corresponding to the four acetoxy methyl groups and also at
δ 94.0 consistent with the anomeric carbon. The IR spectrum of 6c showed
the absence of an amide carbonyl band which indicates the formation of
the O-glycoside and not the N -glycoside. Treatment of pyrimidines 1a and
1b with peracetylated ribose (4) under MW irradiation for 30 seconds using
silica gel as a solid support[21] gave the corresponding ribosides 8a and 8b
(Scheme 2).
CH3
CH3
CH3
CO2Et
X
CO2Et
X
N
MWI, 4
N
TEA/MeOH
H2O
CO2Et
X
N
Ar
N
O
Ar
N
O
Ar
N
H
HO
AcO
1a-c
a; Ar = Ph, X = S
OH OH
b; Ar = p.Cl-C6H4, X = S
c; Ar = p.Cl-C6H4, X = O
OAc OAc
9a-c
8a-c
4 = peracetylated ribose
SCHEME 2
1
The H NMR spectra of 8a and 8b showed doublets at δ 6.46 and 6.25,
respectively, characteristic for the anomeric protons. The 13C NMR spectra
of 8a and 8b showed the absence of C=S group and the presence of signals
at δ 161.0 for C-4 and the presence of the anomeric carbons at δ 84.0 and
84.8, respectively.
Riboside 8c was obtained by the reaction of ethyl 2-(4-chlorophenyl)-
6-methyl-4-oxo-3,4-dihydropyrimidine-5-carboxylate (1c) with peracetylated

1064
H. A. El-Sayed et al.
ribose (4) under MW irradiation for 30 seconds using silica gel as a solid
1
support.[21] (See Scheme 2.) The H NMR spectrum of 8c showed three
singlets at δ 1.86, 2.06, and 2.12 for three acetoxy groups and a doublet at δ
6.28 characteristic for the anomeric proton. The IR spectrum of 8c showed
the absence of an amide carbonyl band which indicates the formation of the
O-glycoside and not the N -glycoside.
The deprotected glucosides 7a–c and ribosides 9a–c were obtained
by treatment of the acetylated compounds 6a–c and 8a–c, respectively,
and the reaction mixture was stirred overnight at room temperature. The
1
structures of these products were confirmed by their spectral data (IR, H
1
and 13C NMR). The H NMR spectra revealed the disappearance of the
acetoxy proton signals and the appearance of OH proton signals which
were exchangeable with D2O. The IR spectra showed absorption bands at
3381–3434 cm−1 for OH groups.
In summary, the pyrimidine glycosides were synthesized by reaction of
substituted pyrimidines with glucosyl bromide (2), peracetylated glucose (3)
and peracetylated ribose (4), respectively.
ANTIMICROBIAL ACTIVITY
Glucosides 7a–c and ribosides 8b and 9a were evaluated for antibacterial
activity against Gram (−ve) bacteria (Pseudomonas aeruginosa) and Gram
(+ve) bacteria (Staphylococcus aureus and Bacillus subtilis) using a cup plate
agar diffusion method.[24] Ampicillin was used as a reference to evaluate
the potency of tested compounds. Riboside 8b showed higher antibacterial
activity than the standard drug (ampicillin). Glucoside 7a and riboside 9a
did not show any activity against tested micro-organisms. Glucosides 7b and
7c showed higher activity against Gram (+ve) bacteria than the standard
drug but were inactive against Gram (–ve) bacteria. The results of the
biological activities encourage further work on such a ring system.
TABLE 1 Antimicrobial activity of tested compounds
Compound No.
P. aeruginosa
S. aureus
B. subtilis
7a
7b
7c
8b
—
—
—
25
—
23
—
10
8
9
—
7
—
13
20
11
—
6
9a
Ampicillin
Inhibition zones (mm), minimum inhibitory concentration(µg/mL).

Antimicrobial Activity of Pyrimidine Glycosides
EXPERIMENTAL
1065
All melting points are uncorrected and were measured using an Electro
thermal IA 9100 apparatus. TLC was performed on Merck Silica Gel 60F254
with detection by UV light and by the charring with H2SO4; IR spectra (KBr
disc) were recorded on a Pye Unicam Sp-3-300 or a Shimadzu FTIR 8101
PC infrared spectrophotometer. The UV. Spectra were recorded by UV-
160A, UV-visible recording spectrometer Shimadzu using DMSO (dimethyl-
solphoxid) as a solvent. The 1H and 13C NMR spectra were determined with
JEOL-JNM-LA 200, 300, 400, or 500 MHz spectrometers. The chemical shifts
are expressed on the δ (ppm) scale using TMS as the standard. Elemental
analyses determined on a Perkin Elmer 240 (microanalysis).
General Methods for Preparation of Glucosides and Ribosides
Method A
To a solution of pyrimidinethione 1a and 1b (0.01 mol) in aqueous
KOH [0.01 mol in distilled water (6 mL)] was added a solution of glucosyl
bromide 2 (0.011 mol) in acetone (30 mL); the reaction mixture was stirred
at room temperature for 5 hours and the reaction followed by TLC till the
reaction was finished, the reaction mixture was evaporated and the residue
was washed with distilled water to remove potassium bromide formed. The
product was dried and crystallized from an appropriate solvent.
Method B
A mixture of pyrimidin-4-one or/thione 1a–c (0.001 mol) and (0.001
mol) of peracetylated glucose (3) or ribose (4), respectively, were dis-
solved in a mixture of methylene chloride/methanol (80/20) then 1 g
of silica gel (200–400 mesh) was added, the solvent was removed by
evaporation, the dried residue was transferred into a glass beaker and
irradiated for (0.5–3 minutes) in a domestic microwave oven. The product
was extracted with methylene chloride, decolorized with charcoal and
crystallized from an appropriate solvent or chromatographed on a silica gel
column.
Method C
To a solution of glucosyl bromide 2 (0.011 mol) in dry xylene a
solution of chloromercuric salt (0.01 mol) of the pyrimidinethione 1a in
dry xylene was added. The reaction mixture was refluxed, and followed by
TLC till all starting material was consumed (4 hours), then the solvent was
evaporated under reduced pressure and the residue was extracted by chlo-
roform, the chloroform evaporated and the residue was crystallized from
ethanol.

1066
H. A. El-Sayed et al.
Ethyl 2-phenyl-4-(2ꢁ,3ꢁ,4ꢁ,6ꢁ-tetra-O-acetyl-β-D-glucopyranosylthio)-6-met-
hylpyrimidine-5-carboxylate (6a). Method A: 50% yield; method B: 67%
yield; method C: 15% yield, as colorless crystals from ethanol; m.p.
178–180◦C; Rf = 0.42 (eluent: CHCl3/MeOH, 9.9 : 0.1); UV λmax. 302.1 nm;
IR (KBr) 1760 cm−1, 1731 cm−1 (C=O, acetoxy) and 1701 cm−1 (C=O,
1
ester); H NMR spectrum (300 MHz, DMSO-d6) δ 1.34 (t, 3 H, J = 7.60
Hz CH3CH2), 1.94, 1.98, 1.99 and 2.10 (4s, 12 H, 4 CH3CO), 2.61 (s, 3
H, CH3–6), 3.98 (m, 2 H, H-5ꢁ and H-6ꢁꢁ), 4.38 (m, 3 H, H-6ꢁ and 2 H for
CH3CH2), 4.90 (t, 1 H, J = 8.10 Hz, H-4ꢁ), 5.13 (t, 1 H, J = 8.05 Hz, H-2ꢁ),
5.68 (t, 1 H, J = 8.10 Hz, H-3ꢁ), 6.22 (d, 1 H, J 1 ,2 = 8.00 Hz, H-1ꢁ) and
7.57–8.50 (m, 5 H, Ar-H). 13C NMR (300 MHz, DMSO-d6) δ 13.7, 20.1, 20.1,
20.2, 20.2 and 23.6 (6 CH3), 61.9 (CH3CH2), 61.9 (C-6ꢁ), 68.3 (C-4ꢁ), 68.9
(C-3ꢁ), 72.9 (C-2ꢁ), 74.9 (C-5ꢁ), 79.1(C-1ꢁ), 128.6, 128.7, 129.0, 131.7, 135.6,
161.8, 164.8, 165.8, 165.9, 169.1, 169.2, 169.4 and 169.6 (Ar-C, 2 C=N and 5
acetyl C=O). Anal. Calcd for C28H32 N2O11S (604.63): C, 57.60; H, 5.46; N,
4.63. Found: C, 57.43; H, 5.62; N, 4.63.
ꢁ
ꢁ
Ethyl
2-(4-chlorophenyl)-4-(2ꢁ,3ꢁ,4ꢁ,6ꢁ-tetra-O-acetyl-β-D-glucopyrano-
sylthio)-6-methylpyrimidine-5-carboxylate (6b). Method A: 69% yield;
method B: 70% yield, as colorless crystals from ethanol; m.p. 150–152a˚C;
1
Rf = 0.38 (eluent: CHCl3/MeOH; 9.9 : 0.1); UV λmax. 305 and 223 nm; H
NMR spectrum (500 MHz, DMSO-d6) δ 1.30 (t, 3 H, J = 7.60 Hz, CH3CH2),
1.85, 1.95, 2.00, and 2.50 (4s,12 H, 4 CH3CO), 2.63 (s, 3 H, CH3–6), 3.95
(m, 2 H, H-5ꢁ and H-6ꢁꢁ), 4.4 (m, 3 H, H-6ꢁ and 2 H,CH3CH2),4.90 (t, 1 H,
J = 8.6 Hz, H-4ꢁ), 5.05 (t, 1 H, J = 8.3 Hz, H-2ꢁ), 5.65 (t, 1 H, J = 8.65 Hz,
H-3ꢁ), 6.25 (d, 1 H, J 1 ,2 = 8.3 Hz, H-1ꢁ), 7.60 (d, 2 H, J = 9.6 Hz, Ar-H)
and 8.55 (d, 2 H, J = 9.6 Hz, Ar-H); 13C NMR (500 MHz, DMSO-d6) δ 14.6,
20.7, 21.1, 21.2, 24.7 and 30.4 (6 CH3), 62.8 (CH3CH2), 62.9 (C-6ꢁ), 69.2
(C-4ꢁ), 69.7 (C-3ꢁ), 73.8 (C-2ꢁ), 75.8 (C-5ꢁ), 79.9 (C-1ꢁ), 122.0, 129.7, 131.4,
135.4, 137.6, 161.8, 165.7, 167.0, 167.1, 170.1, 170.2, 170.4 and 170.5 (Ar-C,
2 C=N and 5 acetyl C=O). Anal. Calcd for C28H31Cl N2O11S (638.07): C,
52.62; H, 4.89; N, 4.38. Found: C, 52.45; H, 4.92; N, 4.24.
ꢁ
ꢁ
Ethyl 2-(4-chlorophenyl)-4-(2ꢁ,3ꢁ,4ꢁ,6ꢁ-tetra-O-acetyl-β-D-glucopyrano-
syloxy)-6-methylpyrimidine-5-carboxylate (6c).
Method D
Glucosyl bromide 2 (0.0011 mol) was added to a solution of ethyl 4-oxo-
3,4-dihydropyrimidine-5-carboxylate 1c (0.001 mol) in dry acetonitrile (5
mL); triethylamine (0.2 mL, 0.0014 mol) was added, the reaction mixture
was stirred overnight at room temperature, then cooled in an ice bath and
acidified with acetic acid. The precipitate was collected by filtration, dried
and finally crystallized from ethanol.
Method E
A mixture of ethyl 4-oxo-3,4-dihydropyrimidine-5-carboxylate 1c (0.001
mol) and 0.001 mol potassium carbonate was stirred in acetone or a mixture

Antimicrobial Activity of Pyrimidine Glycosides
1067
of acetone/DMF (15 mL) for 1 hour, then (0.0011 mol) glucosyl bromide
2 was added, the stirring was continued overnight then the mixture was
heated at reflux for 3 hours, filtered, the solvent was evaporated under
vacuum, and the residue was crystallized from ethanol.
Method D: 40% yield; method E : 53% yield, as colorless crystals from
ethanol; m.p. 156–157◦C; Rf = 0.47 (eluent: CH2Cl2/MeOH; 9.9 : 0.1), UV
1
λmax 271 and 242.5 nm; IR (KBr) 1758 and 1731 cm−1 (C=O, ester); H
NMR spectrum (400 MHz, CDCl3) δ 1.37 (t, 3 H, J = 7.12 Hz, CH3CH2),
1.89, 2.00, 2.01 and 2.04 (4s, 12 H, 4 CH3CO), 2.57 (s, 1 H, CH3–6), 4.00 (m,
1 H, H-5ꢁ), 4.14(dd, 1H, J5 ,6 = 2.10, J6 ,6 = 12.3 Hz, H-6ꢁꢁ), 4.22 (dd, 1 H,
ꢁ
ꢁꢁ
ꢁ
ꢁꢁ
J5 ,6 = 5.69, J6 ,6 = 12.3 Hz, H-6ꢁ), 4.39 (q, 2 H, J = 7.12 Hz, CH3CH2),5.15
ꢁ
ꢁ
ꢁ
ꢁꢁ
(t, 1 H, J3 ,4 = 8.97, J4 ,5 = 9.13 Hz, H-4ꢁ), 5.31 (t, 1 H, J1 ,2 = 7.7, J2 ,3 = 9.22
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
Hz, H-2ꢁ), 5.36 (t, 1 H, J2 ,3 = 9.2, J3 ,4 = 8.78 Hz, H-3ꢁ), 6.21 (d, 1 H, J1 ,2
=
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
7.78 Hz, H-1ꢁ), 7.39 (d, 2 H, J = 8.53 Hz, Ar-H), 8.33 (d, 2 H, J = 8.53 Hz,
Ar-H); 13C NMR (400 MHz, CDCl3) δ 14.0, 20.4, 20.5, 20.5, 22.6 and 29.6
(6 CH3), 62.0 (CH3CH2), 62.1 (C-6ꢁ), 68.5 (C-4ꢁ), 70.3 (C-3ꢁ), 72.7 (C-2ꢁ),
72.9(C-5ꢁ), 94.0 (C-1ꢁ), 128.8, 128.9, 129.0, 135.0, 137.7, 162.4, 164.6, 164.9,
167.5, 169.0, 169.3, 170.0 and 170.4 (Ar-C, 2 C=N and 5 acetyl C=O). Anal.
Calcd for C28H31Cl N2O12 (622.16): C, 53.98; H, 5.02; N, 4.50. Found: C,
53.76; H, 5.12; N, 4.57.
Ethyl 2-phenyl-4-(β-D-glucopyranosylthio)-6-methylpyrimidine-5-carbo-
xylate (7a). General method for deacetylation: Triethylamine (1 mL) was added
to a solution of glucosides 6a–c or ribosides 8a–c (0.001 mol) in (10
mL MeOH and 3 drops of water). The mixture was stirred overnight at
room temperature, evaporated under reduced pressure and the residue
was co-evaporated with MeOH until the triethylamine was removed. The
residue was crystallized from ethanol/water to give colorless crystals; 85%
yield; m.p. 190–191◦C; Rf = 0.32 (eluent: CH2Cl2/MeOH; 9.6 : 0.4); IR
1
(KBr) 3411 cm−1 (broad, 4 OH) and 1723 cm−1 (CO, ester); H NMR
spectrum (300 MHz, DMSO-d6) δ 1.34 (t, 3 H, J = 6.93 Hz, CH3CH2), 2.56
(s, 3 H, CH3–6), 3.12–3.50 (m, 6 H, H-6ꢁ, H-6ꢁꢁ, H-5ꢁ, H-4ꢁ, H-3ꢁ and H- 2ꢁ),
4.38 (q, 2 H, J = 6.93 Hz, for CH3CH2), 4.51 (t, 1 H, J = 3.32 Hz, OH-6ꢁ),
5.08 (d, 1 H, J = 4.36 Hz, OH-4ꢁ), 5.23 (d, 1 H, J = 3.84 Hz, OH-3ꢁ), 5.47 (d,
1 H, J = 4.70 Hz, OH-2ꢁ), 5.63 (d, 1 H, J1 ,2 = 7.86 Hz, H-1ꢁ), 7.55–8.39 (m,
5 H, Ar-H). 13C-NMR (300 MHz, DMSO-d6) δ 13.9 and 23.4 (2 CH3), 60.6
(CH3CH2), 61.9 (C-6ꢁ), 69.0 (C-2ꢁ), 63 (C-2ꢁ), 71.8 (C-3ꢁ), 78.6 (C-4ꢁ), 81.7
(C-5ꢁ), 82.8 (C-1ꢁ), 121.4, 128.8, 131.6, 135.2, 136.2, 161.9, 164.7, 165.4 and
167.3 (Ar-C, 2 C = N and C=O). Anal. Calcd for C20H24 N2O7S (436.48):
C, 55.04; H, 5.70; N, 6.40. Found: C, 54.90; H, 6.03; N, 6.27.
ꢁ
ꢁ
Ethyl 2-(4-chlorophenyl)-4-(β-D-glucopyranosylthio)-6-methylpyrimidine
-5-ca rboxylate (7b). As for 7a; crystallized from ethanol/water to give color-
less crystals; 86% yield; m.p. 194–196◦C; Rf = 0.3 (eluent: CH2Cl2/MeOH;
9.6 : 0.4); IR (KBr) 3434 cm−1 (broad, 4 OH) and 1717 cm−1 (CO, ester); 1H

1068
H. A. El-Sayed et al.
NMR spectrum (300 MHz, DMSO-d6) δ 1.33 (t, 3 H, J = 7.0 Hz, CH3CH2),
2.56 (s, 3 H, CH3–6), 3.13–3.64 (m, 6 H, H-6ꢁ, H-6ꢁꢁ, H-5ꢁ, H-4ꢁ, H-3ꢁ and
H-2ꢁ), 4.38 (q, 2 H, J = 7.0 Hz, CH3CH2), 4.5 (t, 1 H, J = 3.56 Hz, OH-6ꢁ),
5.09 (d, 1 H, J = 4.34 Hz, OH-4ꢁ), 5.22 (d, 1 H, J = 4.20 Hz, OH-3ꢁ), 5.47
(d, 1 H, J = 4.96 Hz, OH-2ꢁ), 5.57 (d, 1 H, J1 ,2 = 7.79 Hz, H-1ꢁ), 7.59 (d, 2
H, J = 8.3 Hz, Ar-H) 8.38 (d, 2 H, J = 8.3 Hz, Ar-H); 13C-NMR (300 MHz,
DMSO-d6) δ 13.9 and 23.3 (2 CH3), 60.7 (CH3CH2), 62.0 (C-6ꢁ), 69.6 (C-2ꢁ),
71.6 (C-3ꢁ), 78.5 (C-4ꢁ), 81.8(C-5ꢁ), 82.8 (C-1ꢁ), 121.5, 128.9, 130.2, 135.0,
136.5, 160.9, 164.83, 165.3 and 167.6 (Ar-C, 2 C=N and C=O). Anal. Calcd
for C20H23ClN2O7S (470.92): C, 56.17; H, 6.17; N, 4.9. Found: C, 56.10; H,
6.40; N, 5.07.
ꢁ
ꢁ
Ethyl 2-(4-chlorophenyl)-4-(β-D-glucopyranosyloxy)-6-methylpyrimidin-
5-ca-rboxylate (7c). As for 7a; crystallized from ethanol/water to give color-
less crystals; 85% yield; m.p. 180–182◦C; Rf = 0.42 (eluent: CH2Cl2/MeOH;
9.1 : 0.9); 1H NMR spectrum (200 MHz, DMSO-d6/D2O) δ 1.39 (t, 3 H, J =
7.2 Hz, CH3CH2), 2.58 (s, 3 H, CH3–6), 3.20–3.61 (m, 6 H, H-6ꢁ, H-6ꢁꢁ, H-5ꢁ,
H-4ꢁ, H-3ꢁ and H-2ꢁ), 4.42 (q, 2 H, J = 7.2 Hz, CH3CH2), 6.11 (d, 1 H, J1 ,2
ꢁ
ꢁ
= 7.2 Hz, H-1ꢁ), 7.67 (d, 2 H, J = 8.8 Hz, Ar-H), 8.46 (d, 2 H, J = 8.8 Hz,
Ar-H). Anal. Calcd for C20H23Cl N2O8 (454.11): C, 52.81; H, 5.10; N, 6.16.
Found: C, 53.10; H, 5.22; N, 5.86.
Ethyl
2-phenyl-4-(2ꢁ,3ꢁ,5ꢁ-tri-O-acetyl-β-D-ribofuranosylthio)-6-methyl-
pyrimidine-5-carboxylate (8a). Method B: 82% yield, as Colorless crystals
from methanol; m.p. 79–80◦C; Rf = 0.43 (eluent: CH2Cl2 /MeOH; 9.8 :
1
0.2); UV λmax. 298 nm; H NMR spectrum (200 MHz, CDCl3) δ 1.43 (t, 3
H, J = 5.20 Hz, CH3CH2), 2.06, 2.07 and 2.15 (3s, 9 H, 3 CH3CO), 2.70 (s,
3 H, CH3–6), 4.11(dd, 1 H, J4’,5’ = 3.4, J5 ,5 = 11.6 Hz, H-5ꢁ), 4.16 (dd, 1 H,
ꢁ
ꢁꢁ
J4 ,5 = 3.6, J5 ,5 = 11.6 Hz, H-5ꢁꢁ), 4.42 (m, 3 H, CH3CH2 and H-4ꢁ), 5.54
ꢁ
ꢁꢁ
ꢁ
ꢁꢁ
(dd, 1 H, J2 ,3 = 2.7, J3 ,4 = 6.6 Hz, H-3ꢁ), 5.63 (dd, 1 H, J1 ,2 = 2.6, J2 ,3
=
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
2.80 Hz, H-2ꢁ), 6.46 (d, 1 H, J 1 ,2 = 2.4 Hz, H-1ꢁ), 7.45–8.40 (m, 5 H, Ar-H);
13C NMR (200 MHz, CDCl3) δ 13.0, 19.4, 19.4, 19.7 and 23.2 (5 CH3), 61.1
(CH3CH2), 61.1 (C-5ꢁ), 69.0 (C-3ꢁ), 74.4 (C-2ꢁ), 77.9 (C-4ꢁ), 84.0 (C-1ꢁ),
127.3, 127.6, 127.9, 128.1, 131.3, 134.8, 160.7, 161.0, 164.1, 168.3, 168.5
and 169.0 (Ar-C, 2 C=N and 4 acetyl C=O). Anal. Calcd for C25H28N2O9S
(532.38): C, 56.38; H, 5.30; N, 5.26. Found: C, 56.42; H, 5.21; N, 5.33.
Ethyl 2-(4-chlorophenyl)-4-(2ꢁ,3ꢁ,5ꢁ-tri-O-acetyl-β-D-ribofuranosylthio)-6-
methylpyrimidine-5-carboxylate (8b). Method B: 79% yield, as colorless
crystals from methanol; m.p. 129–130◦C; Rf = 0.38 (eluent: CH2Cl2 /MeOH;
9.8: 0.2); UV λmax 318 and 269.5 nm; 1H NMR spectrum (200 MHz, DMSO-
d6) δ 1.40 (t, 3 H, J = 7.5 Hz, CH3CH2), 2.10, 2.15 and 2.23 (3s, 9 H, 3
ꢁ
ꢁ
ꢁ
ꢁ
ꢁꢁ
CH3CO), 2.69 (s, 3 H, CH3–6), 4.10, (dd, 1 H, J4 ,ꢁ5ꢁꢁ = 4.8, J5 ,5 = 11.2 Hz,
ꢁ
ꢁ
ꢁꢁ
ꢁ
ꢁꢁ
H-5 ), 4.17 (dd, 1 H, J4 ,5 = 4.6, J5 ,5 = 11.2 Hz, H-5 ), 4.50 (m, 3 H,CH3CH2
and H-4ꢁ), 5.48 (dd, 1 H, J2 ,3 = 3.1, J3 ,4 = 6.8 Hz, H-3ꢁ), 5.59 (dd, 1 H, J1 ,2
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
= 2.4, J2 ,3 = 3.0 Hz, H-2ꢁ), 6.44 (d, 1 H, H-1ꢁ, J1 ,2 = 2.4 Hz), 7.60 (d, 2
ꢁ
ꢁ
ꢁ
ꢁ

Antimicrobial Activity of Pyrimidine Glycosides
1069
H, J = 8.4 Hz, Ar-H), 8.35 (d, 2 H, J = 8.4 Hz, Ar-H); 13C NMR (200 MHz,
DMSO-d6) δ 13.8, 20.2, 20.5, 23.9 and 24.0 (5 CH3), 62.0 (CH3CH2), 62.1
(C-5ꢁ), 69.9 (C-3ꢁ), 75.1 (C-2ꢁ), 78.9 (C-4ꢁ),84.8 (C-1ꢁ), 128.9, 129.0, 129.5,
129.9, 134.6, 136.8, 160.7, 161.0, 164.9, 166.0, 169.4 and 169.8 (Ar-C, 2 C=N
and 4 acetyl C=O). Anal. Calcd for C25H27Cl N2O9S (566.11): C, 52.96; H,
4.80; N, 4.94. Found: C, 52.93; H, 4.74; N, 4.86.
Ethyl 2-(4-chlorophenyl)-4-(2ꢁ,3ꢁ,5ꢁ-tri-O-acetyl-β-D-ribofuranosyloxy)-6-
meth- ylpyrimidine-5-carboxylat (8c). Method B: 08% yield, as colorless
crystals chromatographied by using CH2Cl2 as eluent; m.p. 96–97◦C; Rf =
0.3 (eluent: CH2Cl2 /MeOH; 9.8 : 0.2); IR (KBr) 1735 cm−1 (C=O,ester); 1H
NMR spectrum (300 MHz; DMSO-d6) δ 1.40 (t, 3 H, J = 7.5 Hz, CH3CH2),
1.86, 2.06 and 2.12 (3s, 9 H, 3 CH3CO), 2.5 (s, 3 H, CH3–6), 4.12 (m, 2 H,
H-5ꢁ,5ꢁꢁ), 4.38 (m, 3 H, CH3CH2 and H-4ꢁ), 5.46 (m, 2 H, H-2ꢁ and H-3ꢁ),
6.28 (d, 1 H, J1 ,2 = 3.4 Hz, H-1ꢁ), 7.63(d, 2 H, J = 6.9 Hz, Ar-H), 8.04 (d,
2 H, J = 6.9 Hz, Ar-H). Anal. Calcd for C25H27Cl N2O10 (550.14) : C, 54.50;
H, 4.94; N, 5.08. Found: C, 54.72; H, 5.10; N, 5.00.
ꢁ
ꢁ
Ethyl
2-phenyl-4-(β-D-ribofuranosylthio)-6-methylpyrimidin-5–carbo-
xylate (9a). As for 7a; crystallized from ethanol to give colorless crystals;
85% yield; m.p. 148–150◦C; Rf = 0.2 (eluent: CH2Cl2/MeOH; 9.6 : 0.4); IR
(KBr) 3381 cm−1 (broad, 3 OH), 1704 cm−1 (CO, ester); 1H NMR spectrum
(200 MHz, DMSO-d6/D2O) δ 1.41 (t, 3 H, J = 7.00 Hz, CH3CH2), 2.64 (s,
3 H, CH3–6), 3.50–3.60 (m, 2 H, H-5ꢁ and H-5ꢁꢁ), 3.95 (m, 1 H, H-4ꢁ), 4.10
(dd, 1 H, J3 ,4 = 4.8, J2 ,3 = 4.6 Hz, H-3ꢁ), 4.23 (dd, 1 H, J1 ,2 = 3.83 Hz,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
J2 ,3 = 4.60 Hz, H-2ꢁ), 4.47 (q, 2 H, J = 7.00 Hz, CH3CH2), 6.23 (d, 1 H,
ꢁ
ꢁ
J1 ,2 = 3.8 Hz, H-1ꢁ), 7.6–8.51 (m, 5H, Ar-H). Anal. Calcd for C19H22N2O6S
(406.12): C, 56.15; H, 5.46; N, 6.89. Found: C, 55.90; H, 5.57; N, 6.72.
Ethyl 2-(4-chlorophenyl)-4-(β-D-ribofuranosylthio)-6-methylpyrimidin-5-
carboxylate (9b). As for 7a; crystallized from ethanol/water to give colorless
crystals; 87% yield; m.p. 138–140◦C; Rf = 0.38 (eluent: CH2Cl2/MeOH; 9.2
: 0.8); IR (KBr) 3421 cm−1 (broad, 3 OH), 1716 cm−1 (CO, ester); 1H NMR
spectrum (300 MHz, DMSO-d6/D2O) δ 1.32 (t, 3 H, J = 7.2 Hz, CH3CH2),
2.54 (s, 3 H, CH3 -6), 3.54 (m, 2 H, H-5ꢁ and H-5ꢁꢁ), 3.86 (m, 1 H, H-4ꢁ), 4.00
(t, 1 H, J = 3.67 Hz, H-3ꢁ), 4.12 (t, 1 H, J = 3.6 Hz, H-2ꢁ), 4.36 (q, 2 H, J = 7.2
ꢁ
ꢁ
Hz, CH3CH2), 6.12 (d, 1 H, J 1 ,2 = 3.6 Hz, H-1ꢁ), 7.59 (d, 2 H, J = 8.7 Hz,
Ar-H) 8.43 (d, 2 H, J = 8.7 Hz, Ar-H); 13C-NMR (300 MHz, DMSO-d6) δ 20.6
and 20.7 (2 CH3) 62.3 (CH3CH2), 63.2 (C-5ꢁ), 73.0 (C-3ꢁ), 75.3 (C-2ꢁ), 75.8
(C-4ꢁ), 80.6 (C-1ꢁ), 116.0, 129.1, 131.0, 131.3, 134.0, 137.2, 169.0, 169.7 and
169.9 (Ar-C, 2 C=N and C=O). Anal. Calcd for C19H21Cl N2O6S (440.08):
C, 51.76; H, 4.8; N, 6.53. Found: C, 51.77; H, 4.76; N, 6.38.
ꢁ
ꢁ
Ethyl 2-(4-chlorophenyl)-4-(β-D-ribofuranosyloxy)-6-methylpyrimidin-5-
carb-oxylate (9c). As for 7a; crystallized from ethanol/water to give colorless
crystals; 86% yield; m.p. 115–117◦C; Rf = 0.43 (eluent: CH2Cl2/MeOH; 9.2
1
: 0.8); H NMR spectrum (300 MHz, DMSO-d6) δ 1.32 (t, 3 H, J = 7.0 Hz,

1070
H. A. El-Sayed et al.
CH3CH2), 2.49 (s, 3 H, CH3–6), 3.98–4.07 (m, 5 H, H-5ꢁ, H-5ꢁꢁ, H-4ꢁ, H-3ꢁ and
H-2ꢁ), 4.36 (q, 2 H, J = 7.0 Hz, CH3CH2), 4.2 (t, 1 H, J = 5.3 Hz, OH-5ꢁ),
4.26 (d, 1 H, J = 4.87 Hz, OH-3ꢁ), 4.3 (d, 1 H, J = 5.0 Hz, OH-2ꢁ), 6.03 (d,
1 H, J1 ,2 = 3.60 Hz, H-1ꢁ),7.55 (d, 2 H, J = 8.90 Hz, Ar-H), 7.9 (d, 2 H, J =
8.90 Hz, Ar-H). Anal. Calcd for C19H21Cl N2O7 (424.10): C, 53.72; H, 4.98;
N, 6.59. Found: C, 53.54; H, 4.73; N, 6.60
ꢁ
ꢁ
ANTIBACTERIAL SCREENING
The antimicrobial activities of some synthesized compounds were
screened for their antibacterial activity against three species of bacteria,
namely (Pseudomonas aeruginosa) as Gram (−ve), (Staphylococcus aureus), and
(Bacillus subtilis) as Gram (+ve) using a cup agar diffusion method.[23] The
tested compounds were dissolved in dimethyl sulfoxide to get a solution of
1 mg/mL concentration. The inhibition zone were measured in mm at the
end of an incubation period of 48 hours at 37◦C. Dimethyl sulfoxide showed
no inhibition zones. Ampicllin was used as a reference.
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