Synthesis and biological activity of some 4-substituted 1-[1-(2,3-dihydroxy-1-propoxy)methyl-1,2,3-triazol-(4 & 5)-ylmethyl]-1H-pyrazolo[3,4-d]pyrimidines

Article abstract of DOI:10.1016/S0014-827X(01)01152-1

Cycloaddition of 7a, b with 6 gave, after separation and deprotection, two regioisomers 10a, b and 11a, b. The deprotected acyclic nucleoside 10a used as the precursor for the preparation of 4-amino (12), 4-methylamino (13), 4-benzylamino (14), 4-methoxy

Full text of DOI:10.1016/S0014-827X(01)01152-1

Il Farmaco 57 (2002) 27–32
www.elsevier.com/locate/farmac
Synthesis and biological activity of some 4-substituted
1-[1-(2,3-dihydroxy-1-propoxy)methyl-1,2,3-triazol-(4 &
5)-ylmethyl]-1H-pyrazolo[3,4-d]pyrimidines
Omar Moukha-chafiq a, Mohamed Labd Taha a,*, Hassan Bihi Lazrek b,
Jean-Jacques Vasseur c, Christophe Pannecouque d, Myriam Witvrouw d,
Erik De Clercq d
a Laboratoire de Chimie Bio-Organique, Faculte´ des Sciences, Agadir, Morocco
b Laboratoire de Chimie Bio-Organique, Faculte´ des Sciences I, Marrakech, Morocco
c Laboratoire de Chimie Organique Biomole´culaire de synthe`se, U.S.T. de Montpellier II, Montpellier, France
d Rega Institute for Medical Research, Katholieke Uni6ersiteit Leu6en, Leu6en, Belgium
Received 8 May 2001; accepted 31 July 2001
Abstract
Cycloaddition of 7a, b with 6 gave, after separation and deprotection, two regioisomers 10a, b and 11a, b. The deprotected
acyclic nucleoside 10a used as the precursor for the preparation of 4-amino (12), 4-methylamino (13), 4-benzylamino (14),
4-methoxy (15) and 4-hydroxy (16) analogues. All acyclic nucleosides were evaluated for their inhibitory effects against
HIV-1(IIIB), HIV-2(ROD) in MT-4 cells, for their anti-tumor activity and for their inhibitory effects against Mycobacterium
tuberculosis. No marked activity was found. © 2002 Elsevier Science S.A. All rights reserved.
Keywords: Acyclic nucleosides; Pyrazolo[3,4-d]pyrimidine; 1,2,3-Triazole; Biological evaluation
1. Introduction
3a–h (Fig. 1). Their anti-viral evaluation showed that
non significant activity was found.
Nucleoside analogues display a wide range of biolog-
ical activities and have attracted considerable attention
as anti-viral and anti-tumor agents [1]. Amongst these,
nucleosides with an acyclic carbohydrate moiety have
been shown to possess anti-viral activity [2–6]. Acy-
clovir 1 (ACV) and ganciclovir (DHPG) 2 (Fig. 1) have
been approved for clinical use against herpes simplex
virus type 1 and human cytomegalovirus infections,
respectively. In spite of their potent anti-viral activity
each compound suffers from a different problems re-
garding clinical utility [7–10]. Consequently, the search
for new molecules which exhibit high therapeutic in-
dexes is today of great interest for anti-viral research.
In this respect, we recently reported the synthesis of
some acyclic pyrazolo[3,4-d]pyrimidine nucleosides [11]
In connection with this work, and based on our
interest in the insertion of 1,2,3-triazol-(4 or 5)-ylmethyl
between heterocyclic rings and acyclic chains [12–15] or
between nucleosides [16,17], we present the synthesis of
some acyclic nucleosides 10a, b, 11a, b and 12–16
(Scheme 2) in order to determine the influence on
biological evaluation of the 1,2,3-triazol-(4 or 5)-yl-
methyl moiety as a spacer between the 4-substituted
* Correspondence and reprints:.
E-mail address: labd1@caramail.com (M.L. Taha).
Fig. 1.
0014-827X/02/$ - see front matter © 2002 Elsevier Science S.A. All rights reserved.
PII: S0014-827X(01)01152-1

28
O. Moukha-chafiq et al. / Il Farmaco 57 (2002) 27–32
regioisomers (8a+9a) and (8b+9b) in 78 and 84%
overall yield, respectively (Scheme 1). It is well known
from the literature [18] that the addition of azides to
unsymmetrical acetylenes is determined by steric and
electronic factors. In general, such addition tends to
give mainly the isomers with electron withdrawing
groups at the 4-position and electron releasing groups
at 5-position. Thus, after separation of protected
acyclic nucleosides 8a, b and 9a, b on silica gel column
chromatography, compounds 8a, b were obtained as
the major regioisomers in 59 and 64% yield, respec-
tively. The structures of the two regioisomers 8a, b and
9a, b were established by comparison of the chemical
shift values for the triazole ring protons with those
available from a known pair 4- and 5-substituted 1,2,3-
triazole derivatives [12,13,18]. The 1,4-regioisomers 8a,
b showed an H-5 resonance at lower field (8.21 and 8.20
ppm, respectively). For 1,5-regioisomers 9a, b, the H-4
resonance is at higher field (7.70 and 7.59 ppm, respec-
tively). The differences in the chemical shifts between
regioisomers are in agreement with literature data
[12,13,18].
Scheme 1.
The benzoyl and acetyl groups were subsequently
removed from the protected acyclic nucleosides 8a, b
and 9a, b by treatment with a solution of methanol
saturated with ammonia at 25 °C, affording the re-
quired acyclic nucleosides 10a, b and 11a, b in quantita-
tive yield (Scheme 2).
When compound 10a was treated with methanol
saturated with ammonia in a sealed reacting vessel at
100 °C, the acyclic nucleoside 12 was obtained in 85%
yield. Condensation of compound 10a with primary
amines in aqueous or alcohol solution afforded com-
pounds 13 and 14 in 90 and 85% yield, respectively. The
acyclic nucleosides 15 and 16 were synthesized in 84
and 78% yield, respectively, via treatment of 10a with
CH3ONa/CH3OH and NaOH solutions at room tem-
perature (Scheme 2).
Scheme 2.
pyrazolo[3,4-d]pyrimidines and the (2,3-dihydroxy-1-
propoxy)methyl chain. The synthesis and biological
activity are described herein.
Structure identification of the synthetic products was
2. Results and discussion
done by 1H NMR, mass spectra and elemental analysis.
For the synthesis of (3-acetoxy-2-O-benzoyl-1-pro-
poxy)methylazide (6) (Scheme 1), we started from the
5-O-benzoyl-1,3-dioxane (4), which was prepared in
three steps from the glycerol as previously described
[11]. The cleavage of compound 4 with acetyl bromide
gave (3-acetoxy-2-O-benzoyl-1-propoxy)methylbromide
(5), as a clear oil, in 97% yield. Treatment of product 5
with sodium azide in anhydrous N,N-dimethylfor-
mamide (DMF) afforded compound 6 in 93% yield.
The 4-(methyl and benzyl)thio-1-propargyl-1H-pyra-
zolo[3,4-d]pyrimidines (7a, b) (Scheme 1) which have
been described before [12] served as starting materials.
The latter were reacted with azido-compound 6 via
1,3-dipolar cycloaddition reaction, in anhydrous tolu-
ene under reflux, to afford a mixture of two possible
2.1. Biological acti6ity
Compounds 10a, b, 11a, b and 12–16 were evaluated
for their cytotoxicity and their inhibitory effects on
HIV-1(IIIB) and HIV-2(ROD) replication in MT-4
cells. No significant activity was found against the
replication of HIV-1(IIIB) and HIV-2(ROD) at
subtoxic concentration.
These compounds were also evaluated for their anti-
tumor activity using a series of tumor-cell lines
(leukemia, colon cancer, melanoma, ovarian cancer,
renal cancer, prostate cancer, breast cancer, brain can-
cer, non-small cell lung cancer). However, none of the
compounds showed appreciable anti-tumor activity at
compound concentrations lower than 10−4 M.

O. Moukha-chafiq et al. / Il Farmaco 57 (2002) 27–32
29
All above mentioned acyclic nucleosides were also
evaluated for their inhibitory effect against Mycobac-
terium tuberculosis H37Rv (ATCC 27294) in BACTEC
12B medium. No anti-tuberculosis activity was noted at
concentrations up to 12.5 mg/ml. However, compound
7b [14] had potent activity (90% of inhibition at a
concentration of 12.5 mg/ml).
quantitative conversion to 5. Vacuum distillation of this
material gave 12.22 g (97%) of 5. IR (CCl4): w=1741,
1
1725 cm−1. H NMR (CDCl3): l=2.02 (s, 3H, CH3),
3.92 (d, J=4.90 Hz, 2H, OCH2CH), 4.32 (distorted d,
2H, CH2OAc), 5.41 (m, 1H, CHOBz), 5.46 (s, 2H,
OCH2Br), 7.50 and 8.05 (2m, 5H, C6H5). +FAB MS
(3-NBA); m/z: 322 (M+H)+.
4.3. (3-Acetoxy-2-O-benzoyl-1-propoxy)methylazide (6)
3. Conclusions
To a solution of finely ground NaN3 (3.57 g, 55
mmol) in 300 ml of anhydrous DMF was added 12.14
g (36.67 mmol) of freshly distilled compound 5 and the
resulting mixture was heated at 90 °C under stirring for
4 h. The solid was removed and washed with DMF
(3×30 ml). To a combined filtrate and washings was
added 100 ml of water and the mixture was extracted
with ether (4×60 ml). The extracts were combined,
dried (MgSO4) and then evaporated in vacuo to leave a
pale yellow oil. The oil was purified on a column of
silica gel, using hexane as eluent, to give compound 6
(10 g, 93%) as a clear oil. IR (CCl4): w=2120, 1741,
We showed that the 1,3 dipolar cycloaddition reac-
tion is an efficient method to obtain the acyclic 1,2,3-
triazol-(4 and 5)-ylmethyl-1H-pyrazolo[3,4-d]pyrimi-
dine nucleosides with the same acyclic chain as in the
anti-herpetic iso-DHPG, in good yield, from easily
accessible starting materials. Unfortunately, the biologi-
cal evaluation of these compounds has not shown
significant anti-HIV, anti-tumor and anti-tuberculosis
activities. Their anti-herpetic evaluations are in
progress.
1
1725 cm−1. H NMR (CDCl3): l=2.02 (s, 3H, CH3),
4. Experimental procedures
3.92 (d, J=4.90 Hz, 2H, OCH2CH), 4.32 (distorted d,
2H, CH2OAc), 5.41 (m, 1H, CHOBz), 5.50 (s, 2H,
OCH2N3), 7.50 and 8.05 (2m, 5H, C6H5). +FAB MS
(3-NBA); m/z: 294 (M+H)+. Anal. Calc. for
C13H15N3O5 (293.27): C, 53.24; H, 5.15; N, 14.23.
Found: C, 53.47; H, 5.19; N, 14.48%.
4.1. General
Melting points (m.p.) were determined in a Elec-
trothermal digital melting point apparatus and are un-
corrected. The 1H NMR spectra were obtained in a
Bruker AC-250 spectrometer operating at 250 MHz.
The chemical shifts were reported as parts per million
(l ppm) from (CH3)4Si (TMS) as an internal standard.
Key: s (singlet), d (doublet), t (triplet), m (multiplet)
and br (broad). Mass spectra were obtained with a
JEOL JMS DX 300 instrument using fast atomic bom-
bardment (FAB positive), matrix: 3-nitrobenzyl alcohol
(3-NBA) or glycerol–triglycerol (G/T) 1:1. A Perkin–
Elmer 580 instrument was used to determine IR spec-
tra. Thin-layer chromatography (TLC) was performed
on plates of Merck Kieselgel 60 F254 and short wave-
length UV light (254 nm) was used to detect the UV-ab-
sorbing spots. Solvent A: chloroform–MeOH, 90:10,
solvent B: chloroform–MeOH, 80:20. R2f is Rf after two
migrations in hexane–ethyl acetate, 70:30. Column
chromatography separations were obtained on silica gel
60 (70-230 mesh, Merck). Elemental analyses were de-
termined by a French microanalytical central service.
4.4. General procedure for the preparation of 8a, b and
9a, b
A mixture of propargylated heterocycle 7a or 7b (10
mmol) and the azide derivative 6 (15 mmol) in anhy-
drous toluene (100 ml) was refluxed for 38 h. The
reaction was monitored by TLC and was shown to be
completed at this time with formation of two isomers.
The solution was evaporated to dryness. The mixture of
regioisomers was separated in a silica gel column, using
hexane–ethyl acetate (70:30) mixture as eluent, to give:
from the fastest moving band 0.94 g (19%) of 9a or
1.15 g (20%) of 9b (as a white foam) and from the
slowest moving band 2.94 g (59%) of 8a (as an amor-
phous solid) or 3.67 g (64%) of 8b (as a white foam).
4.5. 1-[1-(3-Acetoxy-2-O-benzoyl-1-propoxy)methyl-
1,2,3-triazol-4-ylmethyl]-4-methylthio-1H-pyrazolo-
[3,4-d]pyrimidine (8a)
4.2. (3-Acetoxy-2-O-benzoyl-1-propoxy)methylbromide
(5)
R2f =0.40. M.p. 77–78 °C (CHCl3–hexane). 1H
NMR (DMSO-d6): l=1.92 (s, 3H, CH3), 2.68 (s, 3H,
SCH3), 3.76 (d, J=4.99 Hz, 2H, OCH2CH), 4.20 (m,
2H, CH2OAc), 5.29 (m, 1H, CHOBz), 5.65 (s, 2H,
CCH2N), 5.70 (s, 2H, OCH2N), 7.47–7.88 (m, 5H,
C6H5), 8.21 (s, 1H, aromatic proton of triazole group),
Freshly distilled acetyl bromide (4.70 g, 38.21 mmol)
was stirred magnetically with cooling in an ice bath
while 7.92 g (38.07 mmol) of compound 4 was added
slowly. A rapid exothermic reaction occurred providing

30
O. Moukha-chafiq et al. / Il Farmaco 57 (2002) 27–32
8.31 and 8.77 (2s, 2H, H-3 and H-6). +FAB MS
(3-NBA); m/z: 498 (M+H)+. Anal. Calc. for
C22H23N7O5S (497.52): C, 53.11; H, 4.65; N, 19.70.
Found: C, 53.46; H, 4.91; N, 19.85%.
TLC evaluation indicated that complete deprotection of
the protected product had occurred. Volatile materials
were evaporated in vacuo and the resulting solid was
recrystallized or, if necessary, purified on a column of
silica gel, using chloroform–methanol (96:4) mixture as
eluent, to obtain the expected acyclic nucleoside.
4.6. 1-[1-(3-Acetoxy-2-O-benzoyl-1-propoxy)methyl-
1,2,3-triazol-5-ylmethyl]-4-methylthio-1H-pyrazolo-
[3,4-d]pyrimidine (9a)
4.10. 1-[1-(2,3-Dihydroxy-1-propoxy)methyl-
1,2,3-triazol-4-ylmethyl]-4-methylthio-1H-pyrazolo-
[3,4-d]pyrimidine (10a)
R2f =0.46. 1H NMR (DMSO-d6): l=1.91 (s, 3H,
CH3), 2.66 (s, 3H, SCH3), 3.66 (d, J=4.96 Hz, 2H,
OCH2CH), 4.10 (m, 2H, CH2OAc), 5.14 (m, 1H,
CHOBz), 5.79 (s, 2H, CCH2N), 6.85 (s, 2H, OCH2N),
7.44–7.85 (m, 5H, C6H5), 7.70 (s, 1H, aromatic proton
of triazole group), 8.29 and 8.74 (2s, 2H, H-3 and H-6).
+FAB MS (3-NBA); m/z: 498 (M+H)+. Anal. Calc.
for C22H23N7O5S (497.52): C, 53.11; H, 4.65; N, 19.70.
Found: C, 53.49; H, 4.93; N, 19.89%.
Yield: 0.33 g (94%). Rf=0.52 (solvent A). M.p.
1
106–107 °C (ethanol). H NMR (DMSO-d6): l=2.66
(s, 3H, SCH3), 3.20–3.47 (m, 5H, OCH2CHCH2), 4.50
(t, J=5.64 Hz, 1H, HOCH2, D2O exchangeable), 4.74
(d, J=5.00 Hz, 1H, CHOH, D2O exchangeable), 5.62
(s, 2H, CCH2N), 5.67 (s, 2H, OCH2N), 8.16 (s, 1H,
aromatic proton of triazole group), 8.31 and 8.76 (2s,
2H, H-3 and H-6). +FAB MS (GT); m/z: 352
(M+H)+. Anal. Calc. for C13H17N7O3S (351.37): C,
44.43; H, 4.87; N, 27.90. Found: C, 44.41; H, 4.99; N,
27.88%.
4.7. 1-[1-(3-Acetoxy-2-O-benzoyl-1-propoxy)methyl-
1,2,3-triazol-4-ylmethyl]-4-benzylthio-1H-pyrazolo-
[3,4-d]pyrimidine (8b)
R2f =0.48. 1H NMR (DMSO-d6): l=1.90 (s, 3H,
CH3), 3.75 (d, J=4.97 Hz, 2H, OCH2CH), 4.18 (m,
2H, CH2OAc), 4.65 (s, 2H, SCH2), 5.25 (m, 1H,
CHOBz), 5.64 (s, 2H, CCH2N), 5.69 (s, 2H, OCH2N),
7.22–7.65 (m, 10H, 2 C6H5), 8.20 (s, 1H, aromatic
proton of triazole group), 8.28 and 8.81 (2s, 2H, H-3
and H-6). +FAB MS (3-NBA); m/z: 574 (M+H)+.
Anal. Calc. for C28H27N7O5S (573.62): C, 58.62; H,
4.74; N, 17.09. Found: C, 58.90; H, 4.81; N, 17.21%.
4.11. 1-[1-(2,3-Dihydroxy-1-propoxy)methyl-
1,2,3-triazol-5-ylmethyl]-4-methylthio-1H-pyrazolo-
[3,4-d]pyrimidine (11a)
Yield: 0.33 g (94%). Rf=0.59 (solvent A). M.p.
1
92–93 °C (ethanol). H NMR (DMSO-d6): l=2.73 (s,
3H, SCH3), 3.21–3.47 (m, 5H, OCH2CHCH2), 4.54 (t,
J=5.64 Hz, 1H, HOCH2, D2O exchangeable), 4.78 (d,
J=4.98 Hz, 1H, CHOH, D2O exchangeable), 5.85 (s,
2H, CCH2N), 5.89 (s, 2H, OCH2N), 7.67 (s, 1H, aro-
matic proton of triazole group), 8.42 and 8.84 (2s, 2H,
H-3 and H-6). +FAB MS (GT); m/z: 352 (M+H)+.
Anal. Calc. for C13H17N7O3S (351.37): C, 44.43;
H, 4.87; N, 27.90. Found: C, 44.39; H, 4.98; N,
27.83%.
4.8. 1-[1-(3-Acetoxy-2-O-benzoyl-1-propoxy)-methyl-
1,2,3-triazol-5-ylmethyl]-4-benzylthio-1H-pyrazolo-
[3,4-d]pyrimidine (9b)
R2f =0.55. 1H NMR (DMSO-d6): l=1.90 (s, 3H,
CH3), 3.60 (d, J=4.97 Hz, 2H, OCH2CH), 4.18 (m,
2H, CH2OAc), 4.68 (s, 2H, SCH2), 5.19 (m, 1H,
CHOBz), 5.80 (s, 2H, CCH2N), 6.90 (s, 2H, OCH2N),
7.22–7.65 (m, 10H, 2 C6H5), 7.59 (s, 1H, aromatic
proton of triazole group), 8.30 and 8.80 (2s, 2H, H-3
and H-6). +FAB MS (3-NBA); m/z: 574 (M+H)+.
Anal. Calc. for C28H27N7O5S (573.62): C, 58.62; H,
4.74; N, 17.09. Found: C, 58.96; H, 4.83; N, 17.28%.
4.12. 4-Benzylthio-1-[1-(2,3-dihydroxy-1-propoxy)-
methyl-1,2,3-triazol-4-ylmethyl]-1H-pyrazolo[3,4-d]-
pyrimidine (10b)
Yield: 0.40 g (93%). Rf=0.45 (solvent A). M.p.
100–100 °C (ethanol). 1H NMR (DMSO-d6): l=
3.21–3.48 (m, 5H, OCH2CHCH2), 4.08 (s, 2H, SCH2),
4.53 (t, J=5.64 Hz, 1H, HOCH2, D2O exchangeable),
4.77 (d, J=5.03 Hz, 1H, CHOH, D2O exchangeable),
5.65 (s, 2H, CCH2N), 5.69 (s, 2H, OCH2N), 7.26 (m,
5H, C6H5), 8.18 (s, 1H, aromatic proton of triazole
group), 8.24 and 8.62 (2s, 2H, H-3 and H-6). +FAB
MS (GT); m/z: 428 (M+H)+. Anal. Calc. for
C19H21N7O3S (427.47): C, 53.38; H, 4.95; N, 22.93.
Found: C, 53.27; H, 4.97; N, 22.85%.
4.9. General procedure for the preparation of 10a, b
and 11a, b
To 45 ml of anhydrous methanol saturated with NH3
at −5 °C was added 1 mmol of the protected product
8a, b or 9a, b. The flask was stoppered tightly and the
solution was stirred for 20 h at room temperature (r.t.).

O. Moukha-chafiq et al. / Il Farmaco 57 (2002) 27–32
31
proton of triazole group), 8.07 and 8.25 (2s, 2H, H-3
and H-6), 8.23 (m, 1H, HN, D2O exchangeable).
+FAB MS (3-NBA); m/z: 335 (M+H)+. Anal. Calc.
for C13H18N8O3 (334.33): C, 46.70; H, 5.42; N, 33.51.
Found: C, 46.60; H, 5.44; N, 33.43%.
4.13. 4-Benzylthio-1-[1-(2,3-dihydroxy-1-propoxy)-
methyl-1,2,3-triazol-5-ylmethyl]-1H-pyrazolo[3,4-d]-
pyrimidine (11b)
Yield: 0.40 g (93%). Rf=0.52 (solvent A). M.p.
1
86–87 °C (ethanol). H NMR (DMSO-d6): l=3.20–
4.16. 4-Benzylamino-1-[1-(2,3-dihydroxy-1-propoxy)-
methyl-1,2,3-triazol-4-ylmethyl]-1H-pyrazolo[3,4-d]-
pyrimidine (14)
3.50 (m, 5H, OCH2CHCH2), 4.08 (s, 2H, SCH2), 4.49
(t, J=5.64 Hz, 1 H, HOCH2, D2O exchangeable),
4.73 (d, J=5.01 Hz, 1H, CHOH, D2O exchangeable),
5.80 (s, 2H, CCH2N), 5.83 (s, 2H, OCH2N), 7.26 (m,
5H, C6H5), 7.60 (s, 1H, aromatic proton of triazole
group), 8.27 and 8.62 (2s, 2H, H-3 and H-6). +FAB
MS (GT); m/z: 428 (M+H)+. Anal. Calc. for
C19H21N7O3S (427.47): C, 53.38; H, 4.95; N, 22.93.
Found: C, 53.22; H, 5.00; N, 22.80%.
To a solution of 10a (0.21 g, 0.60 mmol) in abso-
lute ethanol (7 ml) was added 2.43 ml of freshly dis-
tilled benzylamine and the mixture was heated at
reflux temperature with stirring overnight. The solvent
was removed in vacuo, the residue was purified on a
column of silica gel, using chloroform–methanol
(98:2) mixture as eluent, and then recrystallized from
ethanol to give compound 14 (0.21 g, 85%). Rf=0.31
(solvent A). M.p. 115–116 °C (ethanol). 1H NMR
(DMSO-d6): l=3.27–3.57 (m, 5H, OCH2CHCH2),
4.58 (t, J=5.64 Hz, 1H, HOCH2, D2O exchange-
able), 4.77 (d, J=5.00 Hz, 1H, CHOH, D2O ex-
changeable), 4.82 (d, J=5.00 Hz, 2H, HNCH2), 5.62
(s, 2H, CCH2N), 5.70 (s, 2H, OCH2N), 7.27–7.40 (m,
5H, C6H5), 8.15 (s, 1H, aromatic proton of triazole
group), 8.19 and 8.35 (2s, 2H, H-3 and H-6), 8.85 (t,
J=5.00 Hz, 1H, HN, D2O exchangeable). +FAB MS
(3-NBA); m/z: 411 (M+H)+. Anal. Calc. for
C19H22N8O3 (410.43): C, 55.60; H, 5.40; N, 27.30.
Found: C, 55.50; H, 5.42; N, 27.22%.
4.14. 4-Amino-1-[1-(2,3-dihydroxy-1-propoxy)-methyl-
1,2,3-triazol-4-ylmethyl]-1H-pyrazolo[3,4-d]pyrimidine
(12)
Solution of 10a (0.18 g, 0.51 mmol) in 30 ml of
methanol saturated with ammonia (previously satu-
rated at −5 °C) was heated at 100 °C for 20 h in a
sealed reacting vessel. After removal of the solvent,
the resulting solid was recrystallized from 95% etha-
nol to provide pure compound 12 (0.14 g, 85%). Rf=
0.32 (solvent B). M.p. 178–179 °C (ethanol). 1H
NMR
(DMSO-d6):
l=3.18–3.50
(m,
5H,
OCH2CHCH2), 4.50 (t, J=5.64 Hz, 1H, HOCH2,
D2O exchangeable), 4.74 (d, J=5.02 Hz, 1H, CHOH,
D2O exchangeable), 5.51 (s, 2H, CCH2N), 5.62 (s,
2H, OCH2N), 7.70 (br s, 2H, NH2, D2O exchange-
able), 8.06 (s, 1H, aromatic proton of triazole group),
8.09 and 8.17 (2s, 2H, H-3 and H-6). +FAB MS
(GT); m/z: 321 (M+H)+. Anal. Calc. for
C12H16N8O3 (320.30): C, 44.99; H, 5.03; N, 34.98.
Found: C, 44.57; H, 5.01; N, 34.90%.
4.17. 1-[1-(2,3-Dihydroxy-1-propoxy)methyl-1,2,3-
triazol-4-ylmethyl]-4-methoxy-1H-pyrazolo[3,4-d]-
pyrimidine (15)
A solution of 0.20 g (8.60 mmol) of sodium was
dissolved in 50 ml of anhydrous methanol. To this
solution 2 g (5.69 mmol) of compound 10a was
added. The mixture was stirred at r.t. for 5 h. The
resulting clear solution was neutralized with Amber-
lite IRN77. The resin was removed by filtration and
washed with hot methanol (3×50 ml). The filtrate
and washings were combined and evaporated under
reduced pressure to provide a colorless solid. This
solid was recrystallized from ethanol to furnish
acyclic nucleoside 15 (1.60 g, 84%); Rf=0.40 (solvent
A). M.p. 108–109 °C (ethanol). 1H NMR (DMSO-
d6): l=3.24–3.50 (m, 5H, OCH2CHCH2), 4.10 (s,
3H, CH3), 4.53 (t, J=5.64 Hz, 1H, HOCH2, D2O
exchangeable), 4.77 (d, J=4.96 Hz, 1H, CHOH, D2O
exchangeable), 5.67 (s, 2H, CCH2N), 5.71 (s, 2H,
OCH2N), 8.20 (s, 1H, aromatic proton of triazole
group), 8.25 and 8.63 (2s, 2H, H-3 and H-6). +FAB
MS (3-NBA); m/z: 336 (M+H)+. Anal. Calc. for
C13H17N7O4 (335.31): C, 46.56; H, 5.11; N, 29.23.
Found: C, 46.31; H, 5.11; N, 29.23%.
4.15. 1-[1-(2,3-Dihydroxy-1-propoxy)methyl-
1,2,3-triazol-4-ylmethyl]-4-methylamino-1H-pyrazolo-
[3,4-d]pyrimidine (13)
A solution of 0.21 g (0.60 mmol) of 10a in 40%
aqueous methylamine (6.3 ml) was refluxed for 10
min. The reaction was monitored by TLC, and was
complete at this time. After cooling, the residue was
coevaporated with benzene (5×4 ml) and the result-
ing solid was recrystallized from ethanol to provide
crystalline 13 (0.18 g, 90%). Rf=0.13 (solvent A).
M.p. 136–137 °C (ethanol). 1H NMR (DMSO-d6):
l=2.93 (d, J=4.56 Hz, 3H, CH3), 3.20–3.50 (m,
5H, OCH2CHCH2), 4.50 (t, J=5.64 Hz, 1H,
HOCH2, D2O exchangeable), 4.74 (d, J=4.96 Hz,
1H, CHOH, D2O exchangeable), 5.52 (s, 2H,
CCH2N), 5.62 (s, 2H, OCH2N), 8.03 (s, 1H, aromatic

32
O. Moukha-chafiq et al. / Il Farmaco 57 (2002) 27–32
4.18. 1-[1-(2,3-Dihydroxy-1-propoxy)methyl-1,2,3-
triazol-4-ylmethyl]-4-hydroxy-1H-pyrazolo[3,4-d]-
pyrimidine (16)
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Acknowledgements
This work has been supported by ‘Programme d’Ap-
pui a` la Recherche Scientifique, PARS 51, Maroc’ and
by the ‘Biomedical Research Programme of the Eu-
ropean Commission’. We thank L. Narayanan, PhD
and E. Sausville, PhD (National Cancer Institute, MD,
USA) for the evaluation of the anti-tumor activity.
Cecil D. Kwong, PhD (Southern Research Institute,
AL, USA) is gratefully acknowledged for the evalua-
tion of the anti-tuberculosis activity.
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(1997) 1004–1009.