1398 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8
van Tilburg et al.
insertion probe for EI experiments (70 eV with resolution 1000)
or on a Finnigan MAT TSQ-70 spectrometer equipped with
an electrospray interface for ESI experiments. Spectra were
collected by constant infusion of the analyte dissolved in 80/
20 methanol/H2O. ESI is a soft ionization technique resulting
in protonated, sodiated species in positive ionization mode and
deprotonated species in negative ionization mode.
Resolution of the compounds was achieved by reverse-phase
HPLC (Gilson HPLC system, 712 system controller software;
Gilson Netherlands, Meyvis en Co BV, Bergen op Zoom, The
Netherlands) using a 65% MeOH/31.5% H2O/3.5% CH3CN (v/
v) mobile phase, an Alltima C18 5-µm (250 mm × 4.6 mm) or
a nucleotide/nucleoside 7-µm (250 mm × 4.6 mm) column
(Alltech Nederland BV, Breda, The Netherlands) at a flow rate
of 0.7 mL/min. The peaks were defined by measurement of
UV absorbance (254 nm). Retention times are given. Melting
points (not corrected) were determined in a Bu¨chi capillary
melting point apparatus.
Syn th eses. Gen er a l P r oced u r e for th e Am in a tion of 1
in to Com p ou n d s 2 a n d 8.15 To a solution of 1 (0.98 g, 3.42
mmol) in absolute ethanol (35 mL) were added the correspond-
ing amine (6.84 mmol) and dry triethylamine (4.27 mmol, 0.60
mL), and the mixture was refluxed overnight at 80 °C. The
solution was allowed to cool and was concentrated in vacuo.
Water (50 mL) was added to the residue, and this aqueous
layer was extracted with three portions of ethyl acetate (30
mL). The organic layer was dried with MgSO4, filtered, and
concentrated. The product was crystallized from methanol.
Hz, 1H, 2′-OH), 5.47 (dd, J ) 4.81 Hz, J ) 1.37 Hz, 1H, 3′-
OH), 4.76-4.69 (m, 2H, NHCH2), 4.76-4.69 (m, 1H, H-2′),
4.29-4.17 (m, 1H, H-3′), 4.17-4.02 (m, 1H, H-4′), 4.02-3.75
(m, 2H, H-5′); 13C NMR (DMSO-d6) δ 154.5 (C-6), 152.5 (C-2),
149.8 (C-4), 140.1 (NHCH2C, benzyl), 139.9 (C-8), 128.1 (CCH,
benzyl), 127.0 (CCHCH, benzyl), 126.5 (CCHCHCH, benzyl),
119.2 (C-5), 87.5 (C-1′), 83.6 (C-4′), 72.6 (C2′), 71.2 (C-3′), 44.7
(NHCH2), 44.7 (C-5′); MS m/ z 376 (M + H)+; HPLC, nucle-
otide/nucleoside column; retention time 6.77 min. Anal.
(C17H18N5O3Cl‚0.1CH3CO2C2H5‚0.4 H2O) C, H, N.
5′-Ch lor o-5′-d eoxy-N6-(3-iod oben zyl)a d en osin e (9). The
reaction was carried out with N6-(3-iodobenzyl)adenosine (8;
1.33 g, 2.77 mmol): yield 1.38 g (2.75 mmol, 99%); mp 192-
1
194 °C; H NMR (DMSO-d6) δ 8.46 (bs, 1H, NH), 8.38 (s, 1H,
H-8), 8.22 (s, 1H, H-2), 7.71 (s, 1H, CCHCI), 7.57 (d, J ) 7.56
Hz, 1H, CCHCICH), 7.35 (d, J ) 7.55 Hz, 1H, CCHCH), 7.09
(t, J ) 7.55 Hz, 1H, CCHCH), 5.94 (d, J ) 5.49, 1H, H-1′),
5.59 (d, J ) 6.17 Hz, 1H, 2′-OH), 5.45 (d, J ) 4.80 Hz, 1H,
3′-OH), 4.77-4.64 (m, 2H, NHCH2), 4.77-4.64 (m, 1H, H-2′),
4.24-4.21 (m, 1H, H-3′), 4.10-4.07 (m, 1H, H-4′), 3.93-3.84
(m, 2H, H-5′); 13C NMR (DMSO-d6) δ 154.6 (C-6), 152.4 (C-2),
142.7 (C-4), 135.6 (CCHCICH, benzyl), 135.2 (CCHCI), 132.4
(NHCH2C), 130.3 (CCHCH), 126.5 (CCHCH), 119.3 (C-5), 94.4
(C-3′), 87.5 (C-1′), 83.6 (C-4′), 72.6 (C-2′), 71.1 (C-3′), 44.7
(NHCH2), 44.7 (C-5′); MS m/ z 502 (M + H)+; HPLC, nucleo-
tide/nucleoside column; retention time 10.79 min. Anal.
(C17H17N5O3ClI) C, H, N.
Gen er a l P r oced u r e for th e In tr od u ction of th e 5′-
(Alk ylth io) Su bstitu en t Sta r tin g fr om Com p ou n d s 3 a n d
9 in to Com p ou n d s 4-7 a n d 10-13, Resp ectively. To a
stirred solution of the corresponding alkylthiol (2.13 mmol)
in NaOH (0.6 mL, 2 M) was added the 5′-chloro-5′-deoxy
compound 3 or 9 (0.21 mmol). DMF was added dropwise until
complete dissolution. The mixture was refluxed for 2 h, cooled,
and acidified with acetic acid, and water was added (10 mL).
The white precipitate formed was filtered and dried. The
product was recrystallized from MeOH and ethyl acetate.
N6-Ben zyla d en osin e (2). The reaction was carried out
with benzylamine (1.10 mmol, 0.12 mL) at 80 °C overnight:
yield 88.4 mg (0.25 mmol, 70%); mp 167-169 °C; Rf 0.29 (10%
1
MeOH in CH2Cl2); H NMR (DMSO-d6) δ 8.43 (bs, 1H, NH),
8.37 (s, 1H, H-8), 7.30-7.17 (m, 5H, benzyl), 8.18 (s, 1H, H-2),
5.87 (d, J ) 6.18 Hz, 1H, H-1′), 5.46-5.37 (m, 2H, 3′-OH, 5′-
OH), 5.19-5.17 (m, 1H, 2′-OH), 4.75-4.69 (m, 2H, NHCH2),
4.69-4.59 (m, 1H, H-2′), 4.15-4.11 (m, 1H, H-3′), 3.98-3.93
(m, 1H, H-4′), 3.74-3.41 (m, 2H, H-5′); HPLC, nucleotide/
nucleoside column; retention time 5.55 min.
N6-Ben zyl-5′-d eoxy-5′-(m eth ylth io)a d en osin e (4). The
reaction was carried out with sodium thiomethoxide (149.0 mg,
2.13 mmol) and 3 (80.0 mg, 0.21 mmol): yield 61.0 mg (0.16
N6-(3-Iod oben zyl)a d en osin e (8). The reaction was carried
out with 3-iodobenzylamine hydrochloride (1.50 g, 5.58 mmol),
at 80 °C overnight: yield 1.05 g (2.17 mmol, 76%); mp 169-
172 °C; Rf 0.43 (CH2Cl2:MeOH ) 96:4); 1H NMR (DMSO-d6) δ
8.56-8.42 (bs, 1H, NH), 8.38 (s, 1H, H-8), 8.20 (s, 1H, H-2),
7.71 (s, 1H, NHCH2CCHCI), 7.57 (pd, J ) 7.9 Hz, 1H,
CCHCICH), 7.33 (pd, 1H, CCHCH), 7.09 (pt, J ) 6.18 Hz, 1H,
CCHCH), 5.89 (d, J ) 6.18 Hz, 1H, H-1′), 5.45 (d, J ) 6.18
Hz, 1H, 2′-OH), 5.39 (pt, 1H, 5′-OH), 5.19 (d, J ) 4.46 Hz, 1H,
3′-OH), 4.78-4.54 (m, 2H, CH2NH), 4.78-4.54 (m, 1H, H-2′),
4.21-4.10 (m, 1H, H-3′), 4.01-3.93 (m, 1H, H-4′), 3.75-3.45
(m, 2H, H-5′); HPLC, nucleotide/nucleoside column; retention
time 4.35 min.
Gen er a l P r oced u r e for th e Ch lor in a tion of Com -
p ou n d s 2 a n d 8 in to 3 a n d 9, Resp ectively. To a stirred
suspension of the starting material (0.22 mmol) in pyridine
(0.44 mmol, 35.6 µL) and CH3CN (0.66 mL) cooled in an ice
bath was slowly added SOCl2 (1.10 mmol, 81 µL). Stirring was
continued at ∼5 °C for 3-4 h with subsequent warming to
ambient temperature overnight. The resulting suspension was
concentrated in vacuo; the 2′,3′-protected intermediate was not
isolated. Then methanol (2 mL), H2O (0.2 mL), and concen-
trated ammonia (0.11 mL) were added, stirring was continued
for 30 min at ambient temperature, and the solution was
concentrated. Water was added (15 mL), the solution was
neutralized (NaHCO3), and the aqueous layer was extracted
with three portions of ethyl acetate (10 mL). The organic layer
was dried with MgSO4, filtered, and concentrated. The yellow
powder thus obtained was stirred in MeOH for 30 min and
filtered yielding the pure white product.
1
mmol, 74%); mp 210-211 °C; H NMR (DMSO-d6) δ 8.35 (s,
1H, H-8), 8.33 (bs, 1H, NH), 8.21 (s, 1H, H-2), 7.34-7.17 (m,
5H, benzyl), 5.90 (d, J ) 5.65 Hz, 1H, H-1′), 5.44 (d, J ) 5.94
Hz, 1H, 2′-OH), 5.26 (d, J ) 5.02 Hz, 1H, 3′-OH), 4.74 (q, J )
5.42 Hz, 1H, H-2′), 4.74 (q, J ) 5.42 Hz, 2H, NHCH2), 4.15 (q,
J ) 4.18 Hz, 1H, H-3′), 4.03 (pq, J ) 3.79 Hz, 1H, H-4′), 2.83
(dq, J ) 15.11 Hz, J ) 5.76 Hz, 2H, H-5′), 2.02 (s, 3H, CH3);
MS m/ z 388.2 (M + H)+; HPLC, nucleotide/nucleoside column;
retention time 8.72 min. Anal. (C18H21N5O3S‚0.5H2O) C, H, N.
N6-Ben zyl-5′-d eoxy-5′-(eth ylth io)a d en osin e (5). The re-
action was carried out with ethanethiol (158 µL, 2.13 mmol)
and 3 (80.0 mg, 0.21 mmol): yield 52.5 mg (0.13 mmol, 61%);
mp 165-166 °C; Rf 0.53 (10% MeOH in CH2Cl2); 1H NMR
(DMSO-d6) δ 8.34 (s, 1H, H-8), 8.28 (bs, 1H, NH), 8.21 (s, 1H,
H-2), 7.34-7.17 (m, 5H, benzyl), 5.90 (d, J ) 5.57 Hz, 1H, H-1′),
5.42 (d, J ) 5.96 Hz, 1H, 2′-OH), 5.23 (d, J ) 5.12 Hz, 1H,
3′-OH), 4.74 (pq, J ) 5.56 Hz, J ) 5.58 Hz, 1H, H-2′), 4.74
(pq, J ) 5.56 Hz, J ) 5.58 Hz, 2H, NHCH2), 4.16 (q, J ) 4.25
Hz, 1H, H-3′), 4.01 (dq, J ) 3.81 Hz, 1H, H-4′), 2.85 (dq, J )
16.33 Hz, J ) 10.58 Hz, 2H, H-5′), 2.51 (q, J ) 7.38 Hz, 2H,
SCH2), 1.13 (t, J ) 7.36 Hz, 3H, CH3); MS m/ z 402.2 (M +
H)+; HPLC, Alltima column; retention time 14.23 min. Anal.
(C19H23N5O3S‚0.7H2O) C, H, N.
N6-Ben zyl-5′-d eoxy-5′-(n -p r op ylth io)a d en osin e (6). The
reaction was carried out with 1-propanethiol (193 µL, 2.13
mmol) and 3 (80.0 mg, 0.21 mmol): yield 76.6 mg (0.18 mmol,
87%); mp 159-160 °C; 1H NMR (DMSO-d6) δ 8.34 (s, 1H, H-8),
8.26 (bs, 1H, NH), 8.20 (s, 1H, H-2), 7.35-7.16 (m, 5H, benzyl),
5.89 (d, J ) 5.58 Hz, 1H, H-1′), 4.73 (pt, J ) 5.36 Hz, 1H,
H-2′),), 4.73 (pt, J ) 5.36 Hz, 2H, NHCH2), 4.15 (t, J ) 4.14
Hz, 1H, H-3′), 4.00 (pq, J ) 6.59 Hz, 1H, H-4′), 2.86 (dq, J )
15.38 Hz, J ) 5.62 Hz, 2H, H-5′), 2.47 (q, J ) 6.50 Hz, 2H,
SCH2), 1.48 (q, J ) 7.23 Hz, 2H, SCH2CH2), 0.85 (t, J ) 7.31
Hz, 3H, CH3); 13C NMR (DMSO-d6) δ 154.4 (C-6, C-4), 152.5
N6-Ben zyl-5′-ch lor o-5′-d eoxya d en osin e (3). The reaction
was carried out with N6-benzyladenosine (2; 1.10 g, 3.03
mmol): yield 1.11 g (2.93 mmol, 97%); mp 200-202 °C; Rf 0.65
(10% MeOH in CH2Cl2); 1H NMR (DMSO-d6) δ 8.49-8.36 (m,
1H, NH), 8.36 (s, 1H, H-8), 8.21 (s, 1H, H-2), 7.35-7.21 (m,
5H, benzyl), 5.93 (d, J ) 4.80 Hz, 1H, H-1′), 5.61 (d, J ) 5.49