LETTER
Synthesis of the C-8 Adduct of Benzo[a]pyrene and Deoxyguanosine
2283
stability of the nucleosidic bond in 1 under irradiation
with a Xe lamp (75 W) together with a cut-off filter (>305
nm). The nucleosidic hydrolysis was analyzed by HPLC-
MS (ESI). As a control reaction complete depurination of
(10) (a) Lakshman, M. K.; Hilmer, J. H.; Martin, J. Q.; Keeler, J.
C.; Dinh, Y. Q. V.; Ngassa, F. N.; Russon, L. M. J. Am.
Chem. Soc. 2001, 123, 7779. (b) Lakshman, M. K.; Gunda,
P. Org. Lett. 2003, 5, 39.
(
(
11) Western, E. C.; Daft, J. R.; Johnson, E. M. II; Gannett, P. M.;
Shaugnessy, K. H. J. Org. Chem. 2003, 68, 6767.
12) Havelková, M.; Dvorák, D.; Hocek, M. Synthesis 2001,
1704.
1
was observed after addition of 1% trifluoroacetic acid in
MeOH within several minutes. In more detailed experi-
ments, MeOH–H O = 1:1 mixtures were used at four dif-
2
ferent pH values (0.5 M citrate buffer, adjusted to pH 5.0,
(13) Schoffers, E.; Olsen, P. D.; Means, J. C. Org. Lett. 2001, 3,
221.
4
4
.0, 3.5 and 2.5). Remarkably, at pH values above 2.5 we
(14) The crude product was purified by column chromatography
on silica gel(hexane) and recrystallized from acetone
could not observe any nucleosidic hydrolysis of 1 in these
samples, not in the dark (up to 20 h) and not under irradi-
ation (up to 5 h). Only at pH 2.5 about 30% depurination
yielding a yellow solid (86%). R = 0.23 (hexane). All
f
spectroscopic data of 3 were in agreement with the published
data: (a) Dewhurst, F.; Kitchen, D. A. J. Chem. Soc., Perkin
Trans. 1 1972, 710. (b) Cho, B. P.; Harvey, R. G. J. Org.
Chem. 1987, 52, 5668.
(
after 30 h) occurred in the sample; this reaction was not
light-dependent.
In conclusion, the modified nucleoside Bp-dG exhibits an
unexpected high stability towards nucleosidic hydrolysis
that occurs only at low pH values and seems not to be sup-
ported by the exposure to light. Thus, the Bp-dG adduct 1
needs further investigation inside the DNA helix. There-
fore, we currently incoporate Bp-dG (1) into oligonucle-
otides via automated phosphoramidite chemistry in order
to explore the potentially carcinogenic photoinduced pro-
cesses in duplex DNA.
(
15) (a) Muramata, M. J. Org. Chem. 2000, 65, 164. (b)Krämer,
C. S.; Zimmermann, T. J.; Sailer, M.; Müller, T. J. J.
Synthesis 2002, 1163.
(16) The crude product was purified by column chromatography
on silica gel (hexane–toluene = 1:1) yielding a yellow solid
1
(
25%). R = 0.23 (hexane–toluene = 1:1). H NMR (500
f
MHz, CDCl ): d = 9.08 (m, 2 H), 8.67 (m, 1 H), 8.44 (d,
3
J = 9.0 Hz, 1 H), 8.35 (d, J = 9.0 Hz, 1 H), 8.24 (d, J = 7.5
Hz, 1 H), 8.10 (d, J = 7.5 Hz, 1 H), 7.97 (m, 2 H), 7.81 (m, 2
13
H), 1.66 (s, 12 H). C NMR (125 MHz, CDCl ): d = 135.17,
3
134.82, 131.72, 131.58, 129.48, 129.14, 128.80, 128.65,
128.49, 128.16, 126.55, 126.36, 126.11, 126.0, 125.76,
125.42, 123.62, 123.57, 122.59, 85.03, 25.68. HRMS (EI):
Acknowledgment
m/z calcd for C H O B: 378.17911; found: 378.17896.
17) All spectroscopic data of 6 were in agreement with the
published data: Gannett, P.; Sura, T. P. Synth. Commun.
We are grateful to Dr. Roderich Süßmuth (University of Tübingen)
who measured the HRMS of 1. We thank Andreas Enthart (Techni-
cal University of Munich) for performing the HSQC experiments.
This work was supported by the Deutsche Forschungsgemeinschaft,
the Volkswagen Foundation and by the Fonds der Chemischen
Industrie. We are grateful to Professor Horst Kessler, Technical
University of Munich, for the generous support.
26 23
2
(
(
1
993, 23, 1611.
18) The crude product was purified by column chromatography
on silica gel (CH Cl –acetone = 4:1, then EtOAc–
2
2
MeOH = 10:1, then EtOAc–MeOH–H O = 10:1:0.5)
2
yielding a yellow solid (25%). Analytical HPLC (RP-18
column, gradient A:B = 10:90 to 90:10 over 45 min,
References
A = MeCN, B = H O) was performed to ensure the purity of
2
1
of >99.5%. R = 0.40 (EtOAc–MeOH–H O = 10:1:0.5).
f
2
(
(
(
1) Luch, A. Chem. Unserer Zeit 2001, 35, 294.
NMR signals were assigned based on 2D NMR
2) Lowe, S. W.; Lin, A. W. Carcinogenesis 2000, 21, 485.
3) Lakshman, M. K.; Ngassa, F. N.; Bae, S.; Buchanan, D. G.;
Hahn, H.-G.; Mah, H. J. Org. Chem. 2003, 68, 6020.
4) Rama Krishna, N. V. S.; Fao, G.; Padmavathi, N. S.;
Cavalieri, E. L.; Rogan, E. G.; Cerny, R. L.; Gross, M. L.
Chem. Res. Toxicol. 1992, 5, 293.
5) (a) Rogan, E. G.; Cavalieri, E. L.; Tibbels, S. R.; Cremonesi,
P.; Warner, C. D.; Nagel, D. L.; Tomer, K. B.; Cerny, R. L.;
Gross, M. L. J. Am. Chem. Soc. 1988, 110, 4023.
1
measurements (HSQC). H NMR (500 MHz, DMSO-d ):
6
d = 10.90 (br s, 1 H, NH), 9.34 (m, 2 H, H-10, H-11), 8.57
(
d, J = 9.2 Hz, 1 H, H-12), 8.45 (d, J = 7.9 Hz, 1 H, H-1),
(
(
8
(
0
.27 (d, J = 7.4 Hz, 1 H, H-3), 8.08 (m, 2 H, H-2, H-4), 7.91
m, 1 H, H-9), 7.83 (m, 1.5 H, H-8, H-7), 7.61 (d, J = 8.3 Hz,
.5 H, H-7), 7.55 (d, J = 9.5 Hz, 0.5 H, H-5), 7.40 (d, J = 9.5
Hz, 0.5 H, H-5), 6.53 (br s, 2 H, NH ), 5.47 (m, 1 H, H-1¢),
2
4
.36 (m, 1 H, H-3¢), 3.76 (m, 1 H, H-4¢), 3.58 (m, 1 H, H-5¢),
.46 (m, 1 H, H-5¢), 2.81 (m, 1 H, H-2¢), 1.70 (m, 1 H, H-2¢).
3
(
b) Cremonesi, P.; Cavalieri, E. L.; Rogan, E. G. J. Org.
13
C NMR (125 MHz, DMSO-d ): d = 157.49, 156.30,
6
Chem. 1989, 54, 3561.
1
4
9
1
54.27, 132.58 (C-7), 130.02 (C-12), 130.33 and 127.83 (C-
and C-2), 128.05, 127.75 (C-1), 127.08 (C-3), 127.66 (C-
), 126.05, 125.93 (C-5), 123.43 and 124.94 (C-10 and C-
1), 121.35, 88.80 (C-4¢), 85.97 (C-1¢), 71.93 (C-3¢), 62.94
(
6) (a) Chen, L.; Devanesan, P. D.; Higginbotham, S.; Ariese,
F.; Jankowiak, R.; Small, G. J.; Rogan, E. G.; Cavalieri, E.
L. Chem. Res. Toxicol. 1996, 9, 987. (b) Devanesan, P. D.;
Higginbotham, S.; Ariese, F.; Jankowiak, R.; Suh, M.;
Small, G. J.; Cavalieri, E. L.; Rogan, E. G. Chem. Res.
Toxicol. 1996, 9, 1113.
(
C-5¢), 37.39 (C-2¢). HRMS (ESI/FTICR): m/z calcd for
+
C H N O [M + H]: 518.18228; found: 518.18207.
3
0
23
5
4
(
19) Steady-state fluorescence spectroscopy was performed at r.t.
on a Spex Fluoromax III spectrometer. The emission spectra
are corrected according to detection system variation with
wavelength. UV/Vis absorbance spectroscopy was
(
(
7) Lhomme, J.; Constant, J.-F.; Demeunynck, M. Biopolymers
1
999, 52, 65.
8) (a) Amann, N.; Wagenknecht, H.-A. Synlett 2002, 687.
b) Mayer, E.; Valis, L.; Huber, R.; Amann, N.;
(
performed at r.t. on a Varian Cary 100 photometer. Dry
Wagenknecht, H.-A. Synthesis 2003, 2335.
solvents (Fluka puriss. over molecular sieve, H O <0.01%)
2
(
9) See reviews: (a) Lakshman, M. K. J. Organomet. Chem.
were used for the measurements.
2002, 653, 234. (b) Agrofoglio, L. A.; Gillaizeau, I.; Saito,
Y. Chem. Rev. 2003, 103, 1875. (c) Hocek, M. Eur. J. Org.
Chem. 2003, 245.
Synlett 2005, No. 15, 2281–2284 © Thieme Stuttgart · New York