Synthesis and antiviral evaluation of AZT analogues with a spacer arm between glucidic and base moieties. Part II

Article abstract of DOI:10.1080/15257770701426153

This article describes the synthesis of a series of AZT analogues bearing an acyclic chain between the sugar and the base moieties is described. These new compounds were readily obtained using microwave irradiation. The compounds were characterized by 1H

Full text of DOI:10.1080/15257770701426153

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Synthesis and Antiviral Evaluation of Azt
Analogues with A Spacer Arm Between
Glucidic and Base Moieties. Part II
Vincent Roy a , Rachida Zerrouki a , Pierre Krausz a , Géraldine
Laumond b & Anne Marie Aubertin b
a Université de Limoges, Laboratoire de Chimie des Substances
Naturelles , Faculté des Sciences et Techniques , Limoges, France
b INSERM U 544 , Institut de virologie, Université Louis Pasteur ,
Strasbourg, France
Published online: 19 Jun 2007.
To cite this article: Vincent Roy , Rachida Zerrouki , Pierre Krausz , Géraldine Laumond & Anne
Marie Aubertin (2007) Synthesis and Antiviral Evaluation of Azt Analogues with A Spacer Arm Between
Glucidic and Base Moieties. Part II, Nucleosides, Nucleotides and Nucleic Acids, 26:5, 413-421, DOI:
10.1080/15257770701426153
To link to this article: http://dx.doi.org/10.1080/15257770701426153
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Nucleosides, Nucleotides, and Nucleic Acids, 26:413–421, 2007
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1525-7770 print / 1532-2335 online
DOI: 10.1080/15257770701426153
SYNTHESIS AND ANTIVIRAL EVALUATION OF AZT ANALOGUES
WITH A SPACER ARM BETWEEN GLUCIDIC AND BASE MOIETIES.
PART II
Vincent Roy, Rachida Zerrouki, and Pierre Krausz
Universite´ de Limoges,
2
Laboratoire de Chimie des Substances Naturelles, Faculte´ des Sciences et Techniques,
Limoges, France
Ge´raldine Laumond and Anne Marie Aubertin
INSERM U 544, Institut de
2
virologie, Universite´ Louis Pasteur, Strasbourg, France
This article describes the synthesis of a series of AZT analogues bearing an acyclic chain
2
between the sugar and the base moieties is described. These new compounds were readily obtained
using microwave irradiation. The compounds were characterized by 1H NMR and IR spectroscopy.
Antiviral (HIV-1) properties of these compounds were examined.
Keywords Nucleoside; HIV; microwave; spacer arm
INTRODUCTION
In the continuity of our program to find new anti-HIV nucleosides,[1–4]
we were interested in the preparation of drugs in which thymine is linked to
ribofuranose by an aliphatic chain. Spacer arms have been used in antisense
oligonucleoside synthesis for preventing the enzymatic degradation of DNA
by nucleases.[5] On the other hand, it is well known that increasing the
length of the spacer arm linkage would thus enhance bending of DNA,
leading to base pair opening where the bases then become susceptible
to attack by reactive groups.[6] Taking AZT as a model molecule,[7] we
prepared a new family of AZT analogues 8a, b, c (Scheme 1) whose
lack of 3ꢁ-hydroxyl function should stop DNA elongation, and we studied
Received 10 July 2006; accepted 15 February 2007.
Financial support from the “Conseil Re´gional du Limousin” is gratefully acknowledged. The
authors are grateful to Dr. Michel Guilloton for useful comments on the manuscript.
Address correspondence to Rachida Zerrouki, Universite´ de Limoges, Laboratoire de Chimie des
Substances Naturelles, Faculte´ des Sciences et Techniques, 123, Av. Albert Thomas, 87060 Limoges,
France. E-mail: rachida.zerrouki@unilim.fr
413

414
V. Roy et al.
SCHEME 1 i) NaH, X-(CH2)n-OAc, DMF, MW (4 minutes). ii) KOH/Al2O3, MW (2 minutes). iii) BzCl,
toluene/pyridine, 50◦C. iv) TsCl, pyridine. v) LiN3, DMF, 110◦C. vi) a)CF3COOH 60% b) Ac2O, AcONa,
MW (6 minutes). vii) SnCl4, CH3CN. viii) NH3, MeOH/CH2Cl2.
the influence of the spacer arm and, more precisely, its length on the
inactivation of the human immunodeficiency virus (HIV-1).
RESULTS AND DISCUSSION
N -1 substituted thymine (2a, b, c) derivatives were synthesised according
to the microwave irradiation method described in our preceding article.[1]
The reaction of 1,2-O-isopropylidene-α-D-xylofuranose with benzoyl
chloride in solvent mix (toluene/pyridine; 4/1) gave 3 in 83% yield.[8]
Compound 4 was obtained from 3 in the presence of tosyl chloride in
pyridine, in 74% yield. The azidation reaction was first realized according
to Gautier et al.[9] in reflux DMF in presence of NaN3 during 4 days, but
with no success. We also used the Jeon et al. method[10] in reflux DMF with
NaN3 and 18-crown-6. In this case we did not observe any improvement.
Compound 5 was finally obtained[7] in DMF at 110◦C in presence of 10
[11]
equiv. of LiN3
during 5 days. After purification, we obtained 5 in 51%
yield. The structure of 5 was confirmed by spectroscopic data. IR spectrum
1
displays an azido band at 2107 cm−1 and H NMR indicates the disappear-

Synthesis and Antiviral Evaluation of AZT Analogues
415
ance of the tosyl group and the presence of a benzoyl group. Treatment
of compound 5 with 60% trifluoroacetic acid[12] gave in quantitative yield
1,2-dihydroxyl compound, which was used without further purification after
evaporation of solvent. Acetylation reaction, was achieved under microwave
irradiation during 6 minutes in presence of acetic anhydride and 1.1 equiv.
of sodium acetate.[13] After purification, we obtained 6 in 77.6% yield on 2
steps and a ratio β/α of 85/15 was determined by 1H NMR. We observed a
ratio β/α of 1/1 after microwave activation in presence of acetic anhydride
without sodium acetate.
Syntheses of 7a, b, c were performed by coupling alkylated thymine 2 a,
b, c via Hanessian’s procedure[14] (SnCl4/acetonitrile). After purification,
compounds 7a, b, c were obtained in 74, 72, and 76% yields, respectively;
anomeric ratios (β/α = 85/15 for these three compounds) were deter-
1
mined by H NMR. We eliminate the α anomer by preparative thin layer
chromatography on silica gel. Compounds 8a, b, c were obtained after
removal of the protecting acetyl and benzoyl groups by 7N methanolic NH3.
1
IR spectrum displays a hydroxyl band at 3400 cm−1 and H NMR indicates
the disappearance of the acetyl and benzoyl groups.
BIOLOGICAL EVALUATION
The synthesized compounds 8a, b, c were evaluated for their in vitro
inhibitory effects on the replication of RNA virus (HIV-1) (Table 1). The
anti HIV-1 activity was tested on CEM-SS and MT4 cell lines infected
respectively with HIV-1 LAI and HIV-IIIB according to protocols described
previously.[15] In the case of CEM-SS cells, the production of virus was
measured by quantification of reverse transcriptase activity associated with
the release of virus particles in the culture supernatant; for MT4 cells the
assay was based on the virus induced cytopathogenicity. Cell viability was
evaluated by measuring the activity of mitochondrial electron transport
by the MTT assay.[16] The antiviral activity was expressed as EC50, the
TABLE 1 Biological evaluation
CEM-SS
MT-4
a
b
EC50 CC50 EC50CC50
8a >2.10−1 mg/mL >2.10−1 mg/mL >2.10−1 mg/mL 1.9.10−1 mg/mL
8b >1.10−1 mg/mL >1.10−1 mg/mL >1.10−1 mg/mL >1.10−1 mg/mL
8c >1.10−1 mg/mL >1.10−1 mg/mL >1.10−1 mg/mL >1.10−1 mg/mL
a50% effective concentration (mg/mL) or concentration required to inhibit
HIV-1 replication by 50%.
b50% cytotoxic concentration (mg/mL) or concentration required to reduce
the viability of uninfected cells by 50%.

416
V. Roy et al.
concentration of the compound necessary to reduce virus replication by
50% and was derived from the computer-generated median effect plot of the
dose-effect data.[17] Cytotoxicity was expressed as CC50, the concentration of
drug needed to reduce the viability of uninfected cells by 50%. The results
are summarized in Table 1. For infected CEM-SS cells, the selectivity index
(SI = ratio CC50 /EC50) is low and close to 2, indicating that the compounds
have no specific antiviral activity. Similar results were obtained with the MT4
assay which showed that the drugs did not bring any sensible protection
against the virus-induced cytopathic effect (Table 1).
EXPERIMENTAL SECTION
All the solvents and chemicals were commercially available and, unless
otherwise stated, were used as received. CH2Cl2 and CH3CN were distilled
twice over P2O5 and over CaH2 just before use. Reactions were monitored
by thin-layer chromatography (TLC) on precoated 0.2 mm silica gel 60
F254 (Merck) plates and visualized in several ways: with an ultraviolet
light source at 254 nm, by spraying with sulfuric acid (6 N) and heating
to 200◦C. Silica gel (Merck Kieselgel 60, 15–40 µm) was used for flash
chromatography. Microwave irradiations were performed by the means of
a monomode reactor (Synthewave 402 from Prolabo) with focused waves.
1H NMR spectra were recorded at 400.13 MHz with a Bruker spectrometer.
Chemical shifts (δ) are expressed in ppm with Me4Si as an internal standard
(δ = 0). Data are reported as follows: chemical shift, multiplicity (s, singlet;
d, doublet; t, triplet; q, quartet; quin, quintet; m, multiplet, and br, broad),
coupling constants (Hz), and assignment. Melting points (m.p.) were deter-
mined with a Kofler block and are uncorrected. Rotatory dispersions were
measured with a Jasco (DIP-370) polarimeter in a 1 dm quartz cell at 22 C. IR
spectra were recorded on a Perkin Elmer 1310 grating spectrophotometer
and are reported in wave number (cm−1).
5-O-Benzoyl-1,2-O-isopropylidene-α-D-xylofuranose (3). To a solution of
1,2-O-isopropylidene-α-D-xylofuranose (1 g, 5,26 mmol) in 10 mL of an
anhydrous solvent mix: toluene/pyridine (4/1), we added dropwise with
stirring and cooling 0.644 mL of benzoyl chloride (1.1 eq.) in 1 mL of
toluene over 2.5 hours. The mixture was left to stand for 12 hours at
room temperature and then diluted with water (15 mL). The solution was
extracted with CHCl3 (3 × 30 mL). The organic layer was dried (MgSO4),
filtered, and the solvent removed. The product was purified using flash
chromatography with an elution gradient of CHCl3/petroleum ether and
22
was recovered in 83% yield as a viscous oil (1.283 g). [α]D = +8.49 (c
2.15; CHCl3), Rf = 0.53 (CHCl3/EtOH; 94/6; V/V), IR: 3479 (OH), 2987
(CH), 1698 (C O), 1602 (C C aromatic), 1452 (C-C), 1275 (C-O-C), RMN
1H (CDCl3, δ): 5.96 (d, 1H, J 1,2 = 3.6 Hz, H1), 4.79 (dd, 1H, J 5a,4 = 9.3 Hz,
J 5a, 5b = 12.9 Hz, H5a), 4.59 (t, 1H, J = 3.6 Hz, H2), 4.40 (dd, 1H, J 5b,4
=

Synthesis and Antiviral Evaluation of AZT Analogues
417
4.9 Hz, J 5b,5a = 12.9 Hz, H5b), 4.37 (m, 1H, H4), 4.18 (dd, 1H, J 3,4 = 2.9 Hz,
H3), isopropylidene: 1.50 (s, 3H, CH3), 1.32 (s, 3H, CH3), benzoyl: 8.05 (dd,
2H, J = 1.0 Hz, J = 7.9 Hz), 7.59 (tt, 1H, J = 1.0 Hz, J = 7.5 Hz), 7.45 (br
t, 2H, J = 7.9 Hz).
5-O-Benzoyl-1,2-O-isopropylidene-3-O-paratoluenesulfonyl-α-D-xylofur-
anose (4). To a solution of 2,228 g of 3 (7.578 mmol) in 15 mL of anhydrous
pyridine, we added 3.59 g of tosyl chloride (2.5 eq.). The reaction mixture
was stirred under argon during 15 hours at 50 C. After reaction completion
the solution was quenched with the addition of a saturated NaHCO3
solution and extracted with CH2Cl2 (3 × 20 mL). The organic layer was
washed with 20 mL of water and dried (MgSO4), filtered, and the solvent
removed. The product was purified using flash chromatography with an
elution gradient of AcOEt/petroleum ether and was recovered in 74% yield
22
as a white solid (3.846 g). Tf = 94◦C, [α]D =—68.18 (c 0.8; CHCl3), Rf =
0.43 (CHCl3/EP; 9/1; V/V), IR: 2989 (CH), 1724 (C O ester), 1599 (C C
aromatic), 1452 (C-C), 1273 (C-O-C), RMN 1H (CDCl3, δ): 5.98 (d, 1H, J 1,2
= 3.7 Hz, H1), 4.94 (d, 1H, J 3,4 = 2.9 Hz, H3), 4.82 (d, 1H, J 2,1 = 3.7 Hz, H2),
4.54 (dt, 1H, J 4,3 = 2.9 Hz, J 4,5 = 6.3 Hz, H4), 4.40 (dd, 1H, J 5a,4 = 6.3 Hz,
J 5a,5b = 11.4 Hz, H5a), 4.27 (dd, 1H, J 5b,4 = 6.3 Hz, J 5b,5a = 11.4 Hz, H5b),
isopropylidene: 1.55 (s, 3H, CH3), 1.50 (s, 3H, CH3), benzoyl: 7.91 (dd, 2H, J =
1.0 Hz, J = 7.9 Hz), 7.56 (tt, 1H, J = 1.0 Hz, J = 7.5 Hz), 7.42 (br t, 2H, J =
7.9 Hz), tosyl: 7.77 (d, 2H, J = 8.2 Hz), 7.22 (d, 2H, J = 8.2 Hz), 2.27 (s, 3H,
CH3).
3-Azido-5-O-benzoyl-3-deoxy-1,2-O-isopropylidene-α-D-xylofuranose (5).
To a solution of 0.865 mg of 5-O-benzoyl-1,2-O-isopropylidene-3-O-
paratoluenesulfonyl-α-D-xylofuranose (1.994 mmol) in 10 mL of anhydrous
DMF, we added 0.977 g of lithium azide (10 eq.). The mixture was stirred
under argon during 5 days at 110◦C and was then poured into solvent mix:
H2 O/ CHCl3. The solution was extracted with CHCl3 (3 × 30 mL). The
organic layer was washed with water (2 × 20 mL) and dried (MgSO4),
filtered, and the solvent removed. The product was purified using flash
chromatography with an elution gradient of CHCl3/petroleum ether and
22
was recovered in 51% yield as white solid (324 mg). Tf = 79◦C, [α]D
= +108.13 (c 3.0; CHCl3), Rf = 0.52 (AcOEt/EP; 1/3; V/V), IR: 2987
(CH), 2107 (N3), 1727 (C O ester), 1601 (C C aromatic), 1451 (C-C),
1272 (C-O-C), MS (IC): m/z = 337 (MNH4+), m/z = 320 (MH+) m/z =
292 (MH+- N2), m/z = 279 (MNH4+- C3H6O), m/z = 262 (MH+- C3H6O),
RMN 1H (CDCl3, δ): 5.85 (d, 1H, J 1,2 = 3.7 Hz, H1), 4.79 (dd, 1H, J 2,1 = 3.7
Hz, J 3,2 = 4.4 Hz, H2), 4.68 (dd, 1H, J 5a,4 = 3.2 Hz, J 5a,5b = 12.3 Hz, H5a),
4.48 (dd, 1H, J 5b,4 = 4.4 Hz, J 5b,5a = 12.3 Hz, H5b), 4.39 (ddd, 1H, J 4,5a
3.2 Hz, J 4,5b = 4.4 Hz, J 4,3 = 9.6 Hz, H4), 3.46 (dd, 1H, J 3,2 = 4.4 Hz, J 3,4
=
=
9.6 Hz, H3), isopropylidene:1.61 (s, 3H, CH3), 1.39 (s, 3H, CH3), benzoyl: 8.05
(dd, 2H, J = 1.3 Hz, J = 8.4 Hz), 7.58 (tt, 1H, J = 1.3 Hz, J = 7.4 Hz), 7.45
(br t, 2H, J = 7.9 Hz).

418
V. Roy et al.
1,2-di-O-Acetyl-3-azido-5-O-benzoyl-3-deoxy-D-ribofuranose (6). To a so-
lution of 0.3 g of 3-azido-5-O-benzoyl-3-deoxy-1,2-O-isopropylidene-α-D-
xylofuranose we added 9 mL of TFA at 60%. The mixture was stirred over
2.5 hours and evaporated to dryness. The residue was stirred with 0.085 g
of sodium acetate (1.1 eq.) and 0.532 mL of acetic anhydride (6 eq.) under
microwave irradiation over 6 minutes (P: 48 W). We added 20 mL of CH2Cl2
and the organic phase was washed with a saturated NaHCO3 solution. The
aqueous phase was extracted with CH2Cl2 (2 × 30 mL) and the organic
layer was washed with water (2 × 20 mL) and dried (MgSO4), filtered, and
the solvent removed. The product was purified using flash chromatography
with an elution gradient of AcOEt/petroleum ether and was recovered in
77.6% yield on two steps as a viscous oil (265 mg) with (β/α; 85/15). Rf =
0.58 (AcOEt/EP; 1/2; V/V), IR: 2113 (N3), 1752 (C O ester), 1601 (C C),
1
1272 (C-O-C), RMN H (CDCl3, δ): anomer β: 6.16 (br s, 1H, H1), 5.37 (d,
1H, J 2,3 = 4.7 Hz, H2), 4.67 (dd, 1H, J 5a,4 = 3.8 Hz, J 5a,5b = 12.2 Hz, H5a),
4.60 (dd, 1H, J 5b,4 = 3.8 Hz, J 5b,5a = 12.2 Hz, H5b), 4.37 (q, 1H, J = 3.8 Hz,
H4), 4.22 (dd, 1H, J 3,2 = 4.7 Hz, J 3,4 = 3.8 Hz, H3), anomer α: 6.46 (d, 1H,
J 1,2 = 4.5 Hz, H1), 5.29 (dd, 1H,, J 2,1 = 4.5 Hz, J 2,3 = 7.6 Hz, H2), 4.54 (dd,
1H, J 5a,4 = 4.8 Hz, J 5a,5b = 13.1 Hz, H5a), 4.44–4.48 (m, 2H, H4 and H5a),
4.47 (dd, 1H, J 5b,4 = 4.6 Hz, J 5b,5a = 12.2 Hz, H5b), 4.19 (dd, 1H, J 3,4 = 3.9
Hz, J 3,2 = 7.6 Hz, H3), acetyle: 2.19 (s, 3H, CH3), 1.92 (s, 3H, CH3), benzoyl:
8.08 (dd, 2H, J = 1.2 Hz, J = 7.9 Hz), 7.59 (tt, 1H, J = 1.2 Hz, J = 7.9 Hz),
7.46 (t, 2H, J = 7.9 Hz).
1-(4-(2-O-Acetyl-3-azido-5-O-benzoyl-3-deoxy-D-ribofuranosyloxy)butyl)-
thymine (7a). To a dry system 1,2-di-O-acetyl-3-azido-5-O-benzoyl-3-deoxy-
D-ribofuranose (130 mg, 0.358 mmol) in 5 mL of acetonitrile were added
1-(4-hydroxybutyl)-thymine (71 mg, 1 eq.) and tin (IV) chloride (0.083 mL;
2 eq.). The reaction mixture was kept for 2 hours at room temperature
and the solution was quenched with the addition of a saturated NaHCO3
solution and extracted with CH2Cl2 (3 × 15 mL). The organic layer was
dried (MgSO4), filtered, and the solvent removed. The product was purified
using flash chromatography with an elution gradient of CH2Cl2/MeOH
and was recovered in 74% yield (132 mg). Rf = 0.5 (CH2Cl2/MeOH; 95/5;
V/V), IR: 3193 (NH), 2111 (N3), 2929 (CH alkyl), 1685 (C O Thym), 1272
(C-O-C), RMN 1H (CDCl3, δ): thymine: 8.29 (s, 1H, NH), 6.93 (q, 1H, J 6,CH3
= 1.1 Hz, H6), 1.91 (d, 3H, J CH3,6 = 1.1 Hz, CH3), N-alkyl: 3.72 (dt, 1H, J α,β
= 6.4 Hz, J α,α = 9.8 Hz, Hα), 3.62 (t, 2H, J δ,,γ = 7.4 Hz, Hδ), 3.39 (dt, 1H,
J α,β = 6.4 Hz, J α,α = 9.8 Hz, Hα), 1.65 (m, 2H, Hβ ou Hγ ), 1.48 (m, 2H, Hβ
ꢁ
ꢁ
ꢁ
ꢁ
ou Hγ ), ose: 5.25 (d, 1H, J 2 ,3 = 4.6 Hz, H2 ), 4.98 (br s, 1H, H1 ), 4.60 (dd,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
1H, J 5 a,4 = 4.4 Hz, J 5 a,5 b = 11.8 Hz, H5 a), 4.42 (dd, 1H, J = 4.4 Hz, J =
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
11.8 Hz, H5 b), 4.35 (dt, 1H, J 4 ,5 = 4.4 Hz, J 4 ,3 = 8.1 Hz, H4 ), 4.16 (dd,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
1H, J 3 ,2 = 4.6 Hz, J 3 ,4 = 8.1 Hz, H3 ), benzoyl: 8.07 (dd, 2H, J = 1.3 Hz, J
= 8.4 Hz), 7.59 (tt, 1H, J = 1.3 Hz, J = 7.4 Hz), 7.45 (br t, 2 H, J = 7.9 Hz),
acetyl: 1.60 (s, 3H, CH3).

Synthesis and Antiviral Evaluation of AZT Analogues
419
1-(3-(2-O-Acetyl-3-azido-5-O-benzoyl-3-deoxy-D-ribofuranosyloxy)
propyl)-thymine (7b). Compound 7b was prepared according to the
procedure described for 7 a starting from 1-(3-hydroxypropyl)-thymine (64
mg, 0.349 mmol) and 6 (127 mg, 1 eq.). Yield: 72% (122 mg), Rf = 0.53
(CH2Cl2/ MeOH; 95/5; V/V), IR: 3184 (NH), 2929 (CH alkyl), 2109 (N3),
1682 (C O Thym), 1282 (C-O-C), RMN 1H (CDCl3, δ): thymine: 8.27 (s, 1H,
NH), 6.93 (q, 1H, J 6,CH3 = 1.1 Hz, H6), 1.91 (d, 3H, J CH3,6 = 1.1 Hz, CH3),
N-alkyl: 3.83 (dt, 1H, J α,β = 5.1 Hz, J α,α = 9.8 Hz, Hα), 3.73 (t, 2H, J γ ,β
=
7.4 Hz, Hγ ), 3.46 (dt, 1H, J α,β = 4.9 Hz, J α,α = 9.8 Hz, Hα), 1.67 (m, 2H,
ꢁ
ꢁ
ꢁ
ꢁ
Hβ), ose: 5.24 (d, 1H, J 2 ,3 = 4.6 Hz, H2 ), 4.98 (br s, 1H, H1 ), 4.60 (dd, 1H,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
J 5 a,4 = 4.4 Hz, J 5 a,5 b = 11.8 Hz, H5 a), 4.41 (dd, 1H, J = 4.4 Hz, J = 11.8
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
Hz, H5 b), 4.35 (dt, 1H, J 4 ,5 = 4.4 Hz, J 4 ,3 = 8.1 Hz, H4 ), 4.16 (dd, 1H,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
J 3 ,2 = 4.6 Hz, J 3 ,4 = 8.1 Hz, H3 ), benzoyl: 8.07 (dd, 2H, J = 1.2 Hz, J = 8.4
Hz), 7.59 (tt, 1H, J = 1,2 Hz, J = 7.4 Hz), 7.46 (br t, 2H, J = 7.8 Hz), acetyl:
1.60 (s, 3H, CH3).
1-(3-(2-O-Acetyl-3-azido-5-O-benzoyl-3-deoxy-D-ribofuranosyloxy)ethyl)-
thymine (7c). Compound 7c was prepared according to the procedure
described for 7a starting from 1-(3-hydroxyethyl)-thymine (80 mg, 0.468
mmol) and 6 (170 mg, 1 eq.). Yield: 76% (168 mg), Rf = 0.55 (CH2Cl2/
MeOH; 95/5; V/V), IR: 3189 (NH), 2925 (CH alkyl), 2109 (N3), 1689
1
(C O Thym), 1272 (C-O-C), RMN H (CDCl3, δ): thymine: 8.37 (s, 1H,
NH), 6.93 (q, 1H, J 6,CH3 = 1.1 Hz, H6), 1.91 (d, 3H, J CH3,6 = 1.1 Hz, CH3),
N-alkyl: 3.84 (m, 2H, Hα and Hβ), 3.64 (ddd, 1H, J α,β = 2.9 Hz, J α,β = 4.6
Hz, J = 10.1 Hz, Hα or Hβ), 3.58 (ddd, 1H, J α,β = 2.9 Hz, J α,β = 4.3 Hz, J
ꢁ
ꢁ
ꢁ
= 10.3 Hz, Hα or Hβ), ose: 5.23 (d, 1H, J 2 ,3 = 4.8 Hz, H2 ), 4.98 (br s, 1H,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
H1 ), 4.61 (dd, 1H, J 5 a,4 = 3.7 Hz, J 5 a5 b = 11.7 Hz, H5 a), 4.40 (dd, 1H,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
J 5 b4 = 4.9 Hz, J 5 a5 b = 11.7 Hz, H5 b), 4.35 (m,1H, H4 ), 4.12 (dd, 1H, J 3 ,2
ꢁ
ꢁ
ꢁ
= 4.8 Hz, J 3 ,4 = 7.6 Hz, H3 ), benzoyl: 8.06 (dd, 2H, J = 1.2 Hz, J = 8.4 Hz),
7.60 (tt, 1H, J = 1.2 Hz, J = 7.4 Hz), 7.47 (br t, 2H, J = 7.8 Hz), acetyl: 1.88
(s, 3H, CH3).
1-(4-(3-Azido-3-deoxy-β-D-ribofuranosyloxy)butyl)-thymine (8a). Com-
pound 7a (130 mg, 0.26 mmol) was stirred with methanolic ammonia (7
N) (50 eq., 1.85 mL) in 3 mL of solvent mix: methanol/CH2Cl2 (3/1)
at room temperature during 48 hours. The solvent was removed under
reduced pressure and the crude residue was purified by preparative thin
layer chromatography on silica gel (CH2Cl2/ EtOH) to yield compound 8 a
22
as a viscous oil in 70% (63 mg), [α]D = -15.897◦ (c 0.26; CH3OH), Rf =
0.46 (CH2Cl2/MeOH; 9/1;V/V), IR: 3406 (OH), 2107 (N3), 3021 (CH ar.),
1
2946 (CH alkyl), 1676 (C O Thym), 1451 (C-C), 1273 (C-O-C), RMN H
(CD3OD, δ): thymine: 7.42 (q, 1H, J 6,CH3 = 0.9 Hz, H6), 1.86 (d, 3H, J CH3,6
= 0.9 Hz, CH3), N-alkyl: 3.74–3.76 (m, 1H, Hα), 3.65 (t, 2H, J δ,γ = 7.6 Hz,
Hδ), 3.41 (dt, 1H, J α,β = 6.2 Hz, J α,α = 9.6 Hz, Hα), 1.73 (quin, 2H, J =
7.6 Hz, Hγ ), 1.58 (tt, 2H, J β,α = 6.2 Hz, J β,γ = 7.6 Hz, Hβ), ose: 4.86 (br
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
s, 1H, H1 ), 4.12 (br d, 1H, J 2 ,3 = 4.6 Hz, H2 ), 4.06 (dt, 1H, J 4 ,5 = 5.5

420
V. Roy et al.
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
Hz, J 4 ,3 = 7.7 Hz, H4 ), 3.78 (dd, 1H, J 3 ,2 = 4.6 Hz, J 3 ,4 = 7.7 Hz, H3 ),
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
3.66 (dd, 1H, J 5 a,4 = 5.5 Hz, J 5 a,5 b = 12.3 Hz, H5 a), 3.60 (dd, 1H, J 5 b,4
=
5,5 Hz, J 5 b,5 a = 12,3 Hz, H5 b), RMN 13 C (CD3OD): thymine: 167.06 (C-4),
153.13 (C-2), 111.29 (C-5), 143.32 (C-6), 12.32 (CH3); ose: 108.91 (C-1ꢁ),
82.39 (C-4ꢁ), 77.27 (C-2ꢁ), 64.74 (C-5ꢁ), 63.77 (C-3ꢁ); N -alkyl: 68.37 (C-α),
49.26 (C-δ), 27.63 (C-β), 27.08 (C-γ ).
ꢁ
ꢁ
ꢁ
1-(3-(3-Azido-3-deoxy-β -D-ribofuranosyloxy)propyl)-thymine (8b). Com-
pound 8b was prepared according to the procedure described for 8 a
starting from 7b (100 mg, 0.205 mmol) and stirred with 1.47 mL of
22
methanolic ammonia (7 N) (50 eq.). Yield: 68% (45 mg), [α]D = + 9.933◦
(c 0.4; CH3OH), Rf = 0.57 (CH2Cl2/MeOH; 9/1;V/V), IR: 3363 (OH), 2931
(CH alkyl), 2108 (N3), 1678 (C O Thym), 1473 (C-C), 1259 (C-O-C), RMN
1H (CD3OD, δ): thymine: 7.43 (q, 1H, J 6,CH3 = 1.1 Hz, H6), 1.87 (d, 3H,
J CH3,6 = 1.1 Hz, CH3), N-alkyl: 3.76–3.80 (m,1H, Hα), 3.81 (t, 2H, J γ ,β = 6.3
Hz, Hγ ), 3.44 (dt, 1H, J α,β = 5.8 Hz, J α,α = 10.2 Hz, Hα), 1.92 (quin, 2H, J
ꢁ
ꢁ
ꢁ
ꢁ
= 6.3 Hz, Hβ); ose: 4.84 (br s, 1H, H1 ), 4.12 (br d, 1H, J 2 ,3 = 4.6 Hz, H2 ),
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
4.06 (ddd, 1H, J 4 ,5 = 4.3 Hz, J 4 ,5 = 5.3 Hz, J 4 ,3 = 7.8 Hz, H4 ), 3.78–3.80
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
(m, 1H, H3 ), 3.68 (dd, 1H, J 5 a,4 = 4.3 Hz, J 5 a,5 b = 11.8 Hz, H5 a), 3.60 (dd,
13
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
1H, J 5 b,4 = 5.3 Hz, J 5 b,5 a = 11.8 Hz, H5 b), RMN C (CD3OD): thymine:
167.11 (C-4), 153.13 (C-2), 111.09 (C-5), 143.72 (C-6), 12.32 (CH3); ose:
108.98 (C-1ꢁ), 82.44 (C-4ꢁ), 77.25 (C-2ꢁ), 64.40 (C-5ꢁ), 63.46 (C-3ꢁ); N-alkyl:
63.11 (C-α), 47.25 (C-γ ), 29.97 (C-β).
1-(2-(3-Azido-3-deoxy-β-D-ribofuranosyloxy)ethyl)-thymine (8c). Com-
pound 8c was prepared according to the procedure described for 8 a
starting from 7 c (57 mg, 0.12 mmol) and stirred with 0.86 mL of methanolic
22
ammonia (7 N) (50 eq.). Yield: 77% (29 mg), [α]D = + 22.75◦ (c 0.4;
CH3OH), Rf = 0.43 (CH2Cl2/MeOH; 9/1;V/V), IR: 3350 (OH), 2937 (CH
1
alkyl), 2109 (N3), 1683 (C O Thym), 1472 (C-C), 1259 (C-O-C), RMN H
(CD3OD, δ): thymine: 7.41 (q, 1H, J 6,CH3 = 1.1 Hz, H6), 1.86 (d, 3H, J CH3,6
=
1.1 Hz, CH3), N-alkyl: 3.82–3.97 (m, 3H, Hβ and Hα), 3.60 (m,1H, Hα); ose:
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
4.86 (br s, 1H, H1 ), 4.11 (br d, 1H, J 2 ,3 = 4.6 Hz, H2 ), 4.05 (ddd, 1H, J 4 ,5
=
=
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
4.6 Hz, J 4 ,5 = 5.3 Hz, J 4 ,3 = 7.8 Hz, H4 ), 3.72 (dd, 1H, J 3 ,2 = 4.6 Hz, J 3 ,4
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
7.8 Hz, H3 ), 3.62 (dd, 1H, J 5 a,4 = 5.3 Hz, J 5 a,5 b = 11.8 Hz, H5 a), 3.60 (dd,
13
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
1H, J 5 b,4 = 4.6 Hz, J 5 b,5 a = 11.8 Hz, H5 b), RMN C (CD3OD): thymine:
167.11 (C-4), 153.15 (C-2), 110.74 (C-5), 144.15 (C-6), 12.28 (CH3); ose:
108.83 (C-1ꢁ), 828.62 (C-4ꢁ), 77.27 (C-2ꢁ), 64.32 (C-5ꢁ), 63.46 (C-3ꢁ); N-alkyl:
66.50 (C-α) and (C-β).
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