First route to phosphoramidites of N2-hydrazinoaryl- and N 2-azoaryl-dG adducts and their site-selective incorporation into DNA oligonucleotides

Article abstract of DOI:10.1055/s-2008-1072659

N²-Hydrazinoaryl and N²-azoaryl-dG adducts of border-line carcinogens and the bladder and breast carcinogen 4-aminobiphenyl were prepared using Pd-catalyzed cross-coupling chemistry. After conversion into the phosphoramidites site-sp

Full text of DOI:10.1055/s-2008-1072659

1066
LETTER
First Route to Phosphoramidites of N2-Hydrazinoaryl- and N2-Azoaryl-dG
Adducts and Their Site-Selective Incorporation into DNA Oligonucleotides
DNA Strands
D
amiaged b 2
c
y
N
-Aryla
o
A
dduct
l
s
as Böge, Marcus Schröder, Chris Meier*
Institute of Organic Chemistry, Department of Chemistry, Faculty of Science, University of Hamburg, Martin-Luther-King Platz 6, 20146
Hamburg, Germany
Fax +49(40)428382495; E-mail: chris.meier@chemie.uni-hamburg.de
Received 22 January 2008
highly electrophilic reagents are formed that react with
Abstract: N2-Hydrazinoaryl and N2-azoaryl-dG adducts of border-
bionucleophiles, e.g. the DNA base guanine.5 It is as-
sumed that N-acetoxyarylamines form nitrenium ions
which react in an electrophilic amination reaction with nu-
line carcinogens and the bladder and breast carcinogen 4-aminobi-
phenyl were prepared using Pd-catalyzed cross-coupling chemistry.
After conversion into the phosphoramidites site-specifically dam-
aged oligonucleotides were prepared by automated DNA synthesis. cleophilic centers. Thus, the latter metabolite act as a so-
called ultimate carcinogen.6 As major product with DNA,
DNA Hybrids were studied with respect to their thermal stability
(UV melting-temperature analysis) and circular dichroism.
modification of the C8-position of 2¢-deoxyguanosine as
shown in adduct type 1 (dG) was identified in vivo.7 In
Key words: DNA damage, chemical carcinogenesis, aromatic
amines, N2-adducts, cross-coupling
lower extent the corresponding 2¢-deoxyadenosine (dA)
adduct was also observed.8 Moreover, adducts at the nu-
cleophilic N2-position as shown in the hydrazino com-
DNA contains the blueprint for the proper development, pound 2 and/or the azoaryl-compound 3 of dG were
functioning, and reproduction of every organism. Alter- identified as well in in vivo studies and thus may have
ations affecting the structure and integrity of DNA mole- considerable biological relevance. These adducts have not
cules can arise spontaneously through intrinsic instability been investigated in detail due to missing synthetic access
of chemical bonds in DNA or can be induced by irradia- (Figure 1).9 In addition, also the N2-arylamine dG adducts
tion, oxidative stress, or chemical carcinogens.1 Exposure in which the bond is formed between the N2 atom and the
to carcinogens can occur from environmental or working ortho C atom of the arylamine were found.
conditions, diet, smoking, and endogenous processes.
Poly- and monocyclic aromatic amines belong to the class
In contrast to the biological impact of polycyclic N-aryl-
amines, little is known of their monocyclic counterparts,
of chemical carcinogens that may form covalently bonded
which are classified as borderline carcinogens. Borderline
adducts with DNA. Covalent alteration of DNA (by elec-
carcinogens are less mutagenic/carcinogenic than their
trophiles) may be the reason for the induction of chemical
strongly carcinogenic counterparts. Often they express
carcinogenesis.2 If these covalently bonded modifications
their carcinogenicity only under specific circumstances,
are not repaired, they might compromise the fidelity of
e.g. high and long-lasting exposition to these compounds.
DNA replication, leading to mutations and possibly can-
However, the reasons for this difference remain still un-
cer.3,4 Prior to adduct formation, the aromatic amines un-
clear. Thus, we focused our interest to DNA lesions
derlie a metabolic activation that works parallel to the
caused by monocyclic aromatic amines like aniline, tolu-
detoxification process. Ring oxidation and N-acetylation
idine, or 4-anisidine.10,11
normally led to detoxification. However, N-oxidation cat-
So far, most studies have been done with C8-arylamine
adducts and the properties of damaged DNA strands by
this type of adduct. We and others have reported on syn-
alyzed by monooxigenase cytochrome P450 results in the
formation of N-arylhydroxylamines. If these are esteri-
fied, e.g. by acetyl-CoA to yield N-acetoxyarylamines,
O
O
N
O
N
N
N
Ar
HN
N
N
N
N
NH
NH
NH
N
NH2
N
N
NH
HN
HO
HO
HO
O
O
O
Ar
Ar
OH
OH
OH
1
2
3
Figure 1 In vivo formed nucleobase adducts of arylamines with 2¢-deoxyguanosine
SYNLETT 2008, No. 7, pp 1066–1070
x
x.
x
x.
2
0
0
8
Advanced online publication: 31.03.2008
DOI: 10.1055/s-2008-1072659; Art ID: G02308ST
© Georg Thieme Verlag Stuttgart · New York

LETTER
DNA Strands Damaged by N2-Arylamine Adducts
1067
thetic approaches to such modified adducts using not only cinogenesis by aromatic amines both compounds 8a and
borderline carcinogens, but also poly- and heterocyclic 9a were successfully separated by RP silica gel column
arylamines, the site-specific incorporation into oligonu- chromatography and isolated in 31% and 48% yield (hy-
cleotides as well as the effect on thermal stability, confor- drazinoaryl adducts 8a,b) and in 25% and 27% yield
mation, and replication.12–16
(azoaryl compounds 9a,b).
In addition to the C8-modification we were interested in Compounds 8a,b and 9a,b were 5¢-O-dimethoxytritylated
N2-arylamine adducts, which should interfere with the in- and further converted into 5¢-O-DMTr-3¢-O-phosphor-
terstrand hydrogen-bond pattern within the DNA double amidites 10a,b and 11a,b (28–56% yield for both steps).25
helix.
However, if only the hydrazinoaryl adduct is needed, the
In 1999 de Riccardis et al. published a first synthetic route purification of compounds 8a,b and 10a,b should be done
to N2-arylamine adducts of 2¢-deoxyguanosine, in which using an aluminium oxide (neutral) column chromatogra-
the aromatic ring was bound to the exocyclic amino func- phy to avoid the oxidation to the corresponding azoaryl
tion via a C–N bond.17 Using heterocyclic amines Rizzo derivative.
published the first incorporation of such adducts into oli-
Phosphoramidites 10a,b and 11a,b were used in automat-
ed oligonucleotides synthesis using a modified coupling
gonucleotides.18 Again the arylamine was linked via an
arylamine C atom to the exocyclic amino group of dG.
protocol. For the site-specific incorporation of these ad-
In 2004 Boche et al. reported on the synthesis of N2-(4- ducts into the 30mer sequence 5¢-AAA T(G*)A ACC
dG-aminobiphenyl)-3¢-phosphates using a substitution of TAT CCT CCT TCA GGA CCA ACG-3¢ and a self-com-
triflated 2¢-dG derivative with 4-hydrazinobiphenyl. plementary 12mer 5¢-GTA(G*)AATTCTAC-3¢ the phos-
However, the product was isolated only in moderate phoramidites 10 and 11 were dissolved in acetonitrile.
yields.19 Application of that method to the preparation of The coupling period was tripled compared to the regular
the adduct phosphoramidite failed to obtain sufficient phosphoramidite building blocks. The coupling efficien-
amounts necessary for the coupling reaction.
Here, we disclose the first synthesis of N2-hydrazinoaryl-
cy was about 80% (based on the commonly used trityl as-
say).
and N2-azoaryl-dG-3¢-O-phosphoramidites and their in- After the synthesis the deprotection of the O6-CPE group
corporation into oligonucleotides by automated DNA was achieved by treatment with DBU in pyridine (24 h at
synthesis. In these adducts, the amino function of the ary- r.t.).20 Due to the fact that DBU does not cleave the oligo-
lamine is directly bound to the exocyclic amino group via nucleotide from the CPG solid support, the CPG-bond oli-
an N–N bond of dG as shown in compounds 2 and 3 gonucleotide could be isolated by simple filtration and the
(Figure 1).
cleavage of the base and phosphate protecting groups as
well as the CPG support was done using ammonium hy-
droxide solution and mercaptoethanol.14 Purification of
the oligonucleotides was achieved by reversed-phase
HPLC. The oligonucleotides showed high purity as indi-
cated by HPLC and they were characterized by ESI-MS.
In contrast to Boche’s approach, our synthesis is based on
a palladium-catalyzed cross-coupling approach. There-
fore, it became apparent that the two hydroxyl groups as
well as the O6-position of dG 4 have to be protected.
Thus, first O-silylation using TBDMSCl was performed
to block the hydroxy groups of the 2¢-deoxyribose and
Pfleiderer’s b-cyanophenylethyl (CPE) group was intro-
duced as O6-protection (Scheme 1).20 Finally, the exocy-
clic amino function was converted into bromide 5 using
SbBr3 and tert-butylnitrite (3 steps, 47% overall yield). 2-
Bromopurine nucleoside 5 is the key intermediate for the
cross-coupling reaction leading to the N2-adducts.
All oligonucleotides were hybridized with the comple-
mentary strand and the effect of the incorporated N2-aryl-
amine adducts on the thermal stability of the DNA duplex
was measured by UV melting-curve analysis (Tm). In gen-
eral, the N2-lesions destabilized the DNA duplex. Distur-
bance of the helix is most probably due to lower
hydrogen-bond stabilization. As expected, the effect on
the thermal stability was found to be bigger for the 30mer
oligonucleotides that are damaged by the large, strong
carcinogen 4-aminobiphenyl (3 °C decrease compared to
the unmodified oligonucleotide). The 30mer oligonucle-
otides modified with the borderline carcinogen aniline
showed a moderate destabilization (1.5–2 °C). Interest-
ingly, the effect is not depending on the type of the lesion
since there is no significant difference in the thermal sta-
bility for the hydrazinoaryl- and azoaryl-damaged oligo-
nucleotide.
The subsequent cross-coupling reaction of bromide 5 and
arylhydrazines 6a–d, which are commercially available or
can be easily synthesized,21 was carried out using previ-
ously published conditions.13 However, here the addition
of triethylammonium chloride22 to the reaction mixture
increased the yield of adduct 7a–d from 14–32% up to
52–80% (Scheme 1).23,24
To convert N2-arylamine adducts 7a,b into the corre-
sponding phosphoramidites, first the silyl ethers were
cleaved using triethylammonium trihydrofluoride. During
the separation of product 8a,b using silica gel chromatog-
raphy the oxidation products 9a,b were formed as well
(Scheme 1). Due to the fact that this type of adduct also
plays a role in the possible induction of the chemical car-
The effect of the N2-damage is more significant in the self-
complementary strand. For all N2-modified oligonucle-
otides no formation of a DNA duplex could be observed
at a temperature of 5 °C and, thus, no Tm value could be
measured.
Synlett 2008, No. 7, 1066–1070 © Thieme Stuttgart · New York

1068
N. Böge et al.
LETTER
1. TBDMSCl, imidazole,
py, r.t., 15 h
2. PPh3, DIAD, 2-(4-cyano-
phenyl)ethanol, 1,4-dioxane,
r.t., 15 h
OCPE
O
N
N
N
N
N
N
N
NH
NH2
Br
TBDMSO
HO
3. SbBr3,t-BuNO2, CH2Br2,
–10 °C, 1 h
O
O
47%
OH
OTBDMS
4
5
rac-BINAP, Pd2(dba)3,
K3PO4, Et3NHCl, DME
80 °C, 40–68 h
H
6a,b
N NH2
Ar
50–80 %
OCPE
N
N
H
N
N
N
N
Ar
TBDMSO
H
O
OTBDMS
7a,b
Et3N, Et3N·3HF
CH2Cl2–MeOH (1:1)
r.t., 3 h
31% and 48%
25% and 27%
OCPE
OCPE
N
N
N
H
N
N
N
N
N
N
N
N
Ar
N
Ar
HO
H
HO
O
O
8a,b
9a,b
OH
OH
1. DMTrCl, py, r.t., 15 h
2. DCI, 2-cyano-ethyl-N,N,N',N'-tetraiso-
propylphosphoramidite,
MeCN–CH2Cl2 (1:1), r.t., 18 h
28–35%
52–56%
OCPE
OCPE
N
N
N
N
H
N
N
N
N
N
N
N
Ar
N
Ar
DMTrO
H
DMTrO
O
O
10a,b
11a,b
O
P
O
P
NC
NC
a: Ar = Ph; b: Ar = 4-biphenyl
O
N(i-Pr)2
O
N(i-Pr)2
Scheme 1 Synthesis of the phosphoramidites of N2-dG adducts 10a,b and 11a,b
Additionally, the CD spectra of the 30mer oligonucle- In summary, we have developed an efficient strategy for
otides were recorded. All spectra showed a maximum at the synthesis on N2-arylamine modified adducts of 2¢-
280–290 nm and a minimum at 240–250 nm, which indi- deoxyguanosine involving a palladium-catalyzed cross-
cates that these oligonucleotides adopt a B-type DNA coupling reaction and for their corresponding phosphora-
conformation, no matter if they are damaged by a strong midites. These were suitable for the site-specific incorpo-
or a borderline carcinogen at the N2-position or the C8-po- ration into oligonucleotides via solid-phase synthesis on a
sition.
DNA synthesizer. We have studied the properties of these
Synlett 2008, No. 7, 1066–1070 © Thieme Stuttgart · New York

LETTER
DNA Strands Damaged by N2-Arylamine Adducts
1069
(2 equiv) were suspended in dry DME and stirred at 80 °C.
After the reaction was completed, sat. NaHCO3 and NaCl
solution were added. The layers were separated and the
aqueous layer was extracted three times with EtOAc. The
combined organic layers were dried over Na2SO4 and the
solvent was removed in vacuo. The product was isolated by
column chromatography using PE–EtOAc (10% → 35%).
(24) Compound 7a: The general procedure was conducted with
3.05 g of 5 (4.40 mmol) and 1 mL of 6a (8.8 mmol); yield
2.52 g (3.52 mmol, 80%) of 7a as a slightly brown solid. 1H
NMR (400 MHz, DMSO-d6): d = 8.46 (s, 2 H, H-8), 7.43–
6.82 (m, 9 H, HAr), 6.67 (dd, 3JH,H = 7.3 Hz, 3JH,H = 7.2 Hz,
1 H, H-1¢), 5.34 (s, 2 H, NH), 4.42–4.19 (m, 2 H, H-a), 3.72–
3.71 (m, 3 H, H4¢, H5¢a, H5¢b), 3.06 (t, 3JH,H = 6.9 Hz,
3JH,H = 6.9 Hz, 2 H, Hb), 2.97–2.91 (m, 1 H, H2¢a), 1.91 (s,
1 H, H2¢b), 0.75 [s, 9 H, Si(CH3)3 at C3¢], 0.80 [s, 9 H,
Si(CH3)3 at C5¢], 0.00 [s, 6 H, Si(CH3)2], –0.15 [2 × s, 2 × 3
H, Si(CH3)2] ppm. 13C NMR (101 MHz, DMSO-d6): d =
159.1 (C-6), 156.7 (C-2), 152.4 (C-D), 145.7 (C-A), 144.4
(C-f), 139.6 (C-8), 130.0 (C-C), 129.5 (C-c), 127.6 (C-d),
127.5 (C-e), 123.6 (C-4), 119.0 (C-B), 118.6 (CN), 114.8 (C-
5), 87.1 (C-4¢), 84.0 (C-1¢ 71.6 (C-3¢), 67.8 (C-a), 62.8 (C-
5¢), 39.7 (C-2¢), 34.7 [2 × SiC(CH3)3], 34.3 (C-b) ppm. Mp
84–87 °C; [a]54620 –3 (c 1.0, CHCl3). IR (KBr): 3744, 3037,
1737, 1695, 1612, 1507, 1110, 838 cm–1. HRMS–FAB: m/z
calcd: 715.3698; found: 716.3736 [M + H+].
oligonucleotides containing the lesions concerning their
Tm value and their conformation (CD spectra). Our ap-
proach allows now further biochemical studies with re-
gard to the impact of the lesions on replication and repair.
These studies are currently under way in our laboratories.
Acknowledgment
This work was supported by the Deutsche Forschungsgemeinschaft
(DFG) and the University of Hamburg.
References and Notes
(1) (a) Wagenknecht, H.-A. Angew. Chem. Int. Ed. 2006, 45,
5583; Angew. Chem. 2006, 118, 5709. (b) Carell, T.;
Burgdorf, L. T.; Kundu, L. M.; Cichon, M. Curr. Opin.
Chem. Biol. 2001, 5, 491. (c) Friedberg, E. C.; Walker, G.
C.; Siede, W. DNA Repair and Mutagenesis; American
Society for Microbiology Press: Washington, DC, 1995.
(d) Schärer, O. D. Angew. Chem. Int. Ed. 2003, 42, 2946;
Angew. Chem. 2003, 115, 3052.
(2) Garner, R. C. Mutat. Res. 1998, 402, 67.
(3) Neumann, H. G. Cancer Res. Clin. Oncol. 1986, 112, 100.
(4) Beland, F. A.; Kadlubar, F. F. Environ. Health Perspect.
1985, 62, 19.
Compound 7b: The general procedure was conducted with
2.36 g of 5 (3.42 mmol) and 1.42 g of 6b (7.60 mmol); yield
1.35 g (1.71 mmol, 50%) of 7b as a yellow solid. 1H NMR
(400 MHz, DMSO-d6): d = 8.19 (s, 1 H, H8), 7.77–7.33 (m,
13 H, Har), 6.31 (dd, 3JH,H = 6.7 Hz, 1 H, H1¢), 5.37, 5.20
(2 × s, 2 × 1 H, NH), 4.70 (t, 3JH,H = 6.9 Hz, 2 H, Ha), 4.54–
4.51 (m, 2 H, H3¢), 3.85–3.82 (m, 1 H, H4¢), 3.72–3.62 (m,
2 H, H5¢a, H5¢b), 3.17 (t, 3JH,H = 6.9 Hz, 2 H, Hb), 2.97–2.90
(m, 1 H, H2¢a), 2.30–2.24 (m, 1 H, H2¢b), 0.88, 0.84 [2 × s,
2 × 9 H, Si(CH3)3], 0.10, 0.00 [2 × s, 2 × 6 H, Si(CH3)2] ppm.
13C NMR (101 MHz, DMSO-d6): d = 159.2 (C6), 157.5,
153.1 (C4), 148.2 (C2), 144.1, 139.7 (C8), 132.0, 128.7,
126.1, 118.7 (CN), 115.1 (C5), 87.1 (C4¢), 83.2 (C1¢), 72.3
(C3¢), 65.8 (Ca), 62.8 (C5¢ 38.3 (C2¢), 34.1 (Cb), 25.6, 25.5
[2 × SiC(CH3)3], –5.6, –5.1 [2 × Si(CH3)2] ppm. Mp 75–
78 °C; [a]54620 +25 (c 0.4, CHCl3). IR (KBr): 2954, 2928,
2857, 1687, 1109, 776, 740, 482 cm–1. MS (HRFAB): m/z
calcd: 791.4011; found: 791.4035 [M + H]+.
(5) (a) Famulok, M.; Boche, G. Angew. Chem., Int. Ed. Engl.
1989, 28, 468; Angew. Chem. 1989, 101, 470. (b) Famulok,
M.; Bosold, F.; Boche, G. Tetrahedron Lett. 1989, 30, 321.
(6) Famulok, M.; Bosold, F.; Boche, G. Angew. Chem., Int. Ed.
Engl. 1989, 28, 337; Angew. Chem. 1989, 101, 349.
(7) Swaminathan, S.; Hatcher, J. F. Chem.-Biol. Interact. 2002,
139, 199.
(8) Swaminathan, S.; Hatcher, J. F. Environ. Mol. Mutagen.
2002, 39, 314.
(9) Kadlubar, F. F. Princess Takamatsu Symp. 21 1990, 329.
(10) Meier, C.; Boche, G. Carcinogenesis 1991, 12, 1633.
(11) Meier, C.; Boche, G. Tetrahedron Lett. 1990, 31, 1693.
(12) Elmquist, C. E.; Stover, J. S.; Wang, Z.; Rizzo, C. J. J. Am.
Chem. Soc. 2004, 126, 11189.
(13) Böge, N.; Gräsl, S.; Meier, C. J. Org. Chem. 2006, 71, 9728.
(14) Böge, N.; Szombati, Z.; Meier, C. Nucleosides, Nucleotides
Nucleic Acids 2007, 26, 705.
(15) (a) Takamura-Enya, T.; Ishikawa, S.; Mochizuki, M.;
Wakabayashi, K. Tetrahedron Lett. 2003, 44, 5969.
(b) Takamura-Enya, T.; Ishikawa, S.; Mochizuki, M.;
Wakabayashi, K. Chem. Res. Toxicol. 2006, 19, 770.
(16) (a) Gillet, L. C. J.; Schärer, O. D. Org. Lett. 2002, 24, 4205.
(b) Gillet, L. C. J.; Alzeer, J.; Schärer, O. D. Nucleic Acids
Res. 2005, 33, 1961.
(25) Compound 10a: 1H NMR (400 MHz, benzene-d6): d = 7.84
[s, 1 H, H-8 (I)], 7.81 [s, 1 H, H-8 (II)], 7.71–7.41 [m, 44 H,
HAr (I + II), DMTr-H (I + II)], 6.25 [dd, 3JH,H = 6.4 Hz,
3JH,H = 6.3 Hz, 2 H, H-1¢ (I + II)], 4.74–4.58 [m, 2 H, NH
(I)], 4.47–4.37 [m, 2 H, NH (II)], 4.16–4.05 [m, 4 H, H-a (I
+ II)], 3.58–3.35 (m, 12 H, OCH3, H-5¢a/b (I + II), H-b(I)]
3.15–3.02 [m, 2 H, H-b (II)], 2.54–2.29 (m, 12 H, i-PrH (I +
II), H-a (I + II), H-2¢a/b (I + II)], 1.81 [t, 2 H, H-b (I)], 1.73
[m, 2 H, H-b (II)], 1.15–1.01 [m, 24 H, CH3i-Pr (I + II)] ppm.
13C NMR (101 MHz, benzene-d6): d = 160.1, 159.3, 158.7,
148.2, 145.8, 143.3, 138.0, 137.4, 136.1, 132.0, 131.4,
130.6, 130.1, 129.8, 119.0, 113.7, 113.0, 111.0, 87.1, 74.4,
(17) De Riccardis, F.; Bonala, R. R.; Johnson, F. J. Am. Chem.
Soc. 1999, 121, 10453.
(18) Stover, J. S.; Chowdhury, G.; Zang, H.; Guengerich, F. P.;
Rizzo, C. J. Chem. Res. Toxicol. 2006, 19, 1506.
(19) Haack, T.; Boche, G.; Kliem, C.; Wiessler, M.; Albert, D.;
Schmeiser, H. H. Chem. Res. Toxicol. 2004, 17, 776.
(20) Uhlmann, E.; Pfleiderer, W. Helv. Chim. Acta 1981, 64,
1688.
74.2, 66.0, 54.8, 45.3, 43.6, 35,1, 24.7, 24.6, 22.8 ppm. 31
P
NMR (162 MHz, benzene-d6): d = 149.35, 149.19 ppm. Mp
68–71 °C. [a]54620 +183 (c 1.0, CHCl3). IR KBr): 3870,
3816, 3752, 3744, 3676, 3447, 2966, 1654, 1609, 1581,
1508, 1465, 1383, 1250, 1179, 1034, 829 cm–1. MS–FAB:
m/z calcd: 989.4353; found: 990.5 [M + H]+.
(21) Zeghough, D.; Samsoniya, S.; Suvorov, N. N. Chem.
Heterocycl. Compd. 1990, 3, 343.
(22) Amatore, C.; Azzabi, M.; Jutland, A. J. J. Am. Chem. Soc.
1991, 113, 8375.
Compound 11a: 1H NMR (400 MHz, benzene-d6): d = 7.88
[s, 1 H, H-8 (I)], 7.85 [s, 1 H, H-8 (II)], 7.62–6.58 [m, 49 H,
DMTr-H (I + II), HAr (I + II)], 6.27–6.18 [m, 2 H, H-1¢ (I +
II)], 5.07–4.95 [m, 2 H, H-3¢ (I + II)], 4.73–4.67 [m, 4 H, H-
a (I + II)], 4.13–4.06 [m, 2 H, H-4¢ (I + II)], 3.54–3.26 [m, 20
(23) General Procedure for the Synthesis of the N2-
Arylhydrazino Adducts (7a,b)
Under nitrogen atmosphere 5 (1 equiv), racemic BINAP (30
mol%), Pd2dba3 (10 mol%), K3PO4 (2 equiv),
triethylammonium chloride (0.1 equiv), and arylhydrazine
Synlett 2008, No. 7, 1066–1070 © Thieme Stuttgart · New York

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N. Böge et al.
LETTER
H, OCH3 (I + II), H-b (I + II), H-5¢ (I + II)], 3.00–2.82 [m, 2
H, H-2¢a (I + II)], 2.72–2.61 [m, 8 H, i-PrH (I + II), H-a (I +
II)], 2.56–2.47 [m, 1 H, H-2¢b (I)], 2.41–2.29 [m, 1 H, H-2¢b
(II)], 1.73–1.67 (m, 4 H, H-b (I + II)], 1.13–1.05 [m, 24 H,
CH3i-Pr (I + II)] ppm. 13C NMR (101 MHz, benzene-d6):
d = 190.6, 186.5, 185.4, 177.7, 169.4, 168.0, 163.6, 159.3,
153.4, 146.1, 145.8, 143.3, 136.3, 132.1, 130.7, 129.9,
129.4, 124.0, 113.8, 87.6, 87.0, 54.8, 47.5, 43.6, 35.2, 24.6
ppm. 31P NMR (162 MHz, benzene-d6): d = 149.46, 149.16
ppm. Mp 86–89 °C; [a]54620 +39 (c 1.0, CHCl3). IR (KBr):
3854, 3744, 3676, 3432, 2965, 2227, 1607, 1508, 1445,
1341, 1251, 1178, 1034 cm–1. MS–FAB: m/z calcd:
d = 159.1, 155.6, 153.2, 144.1, 139.7, 135.6, 134.6, 130.0,
127.8, 122.3, 118.8, 116.2, 109.1, 87.6, 83.1, 70.8, 65.8,
61.7, 39.7, 34.4 ppm. 31P NMR (162 MHz, benzene-d6): d =
149.87, 149.09 ppm. Mp 75–78 °C; [a]54620 +33 (c 0.1,
CHCl3). IR (KBr): 3744, 3675, 2966, 1607, 1457, 1200,
1077, 978 cm–1. MS–FAB: m/z calcd 1065.4666; found:
1066.6 [M + H]+.
Compound 11b: 1H NMR (400 MHz, benzene-d6): d = 7.88
[s, 1 H, H8 (I)], 7.86 [s, 1 H, H8 (II)], 7.62–6.58 [m, 59 H,
DMTr-H (I + II), Har (I + II)], 6.29–6.19 [m, 2 H, H1¢ (I +
II)], 5.04–5.01 (m, 2 H, H3¢ (I + II)), 4.60–4.50 [m, 4 H, Ha
(I + II)], 4.13–4.08 [m, 2 H, H4¢ (I + II)], 3.52–3.17 [m, 20
H, OCH3 (I + II), Hb (I + II), H5¢ (I + II)], 2.98–2.93 [m, 1
H, H2¢a (I)], 2.89–2.84 [m, 1 H, H2¢a (II)], 2.71–2.68 [m, 8
H, i-PrH (I + II) + a¢ (I + II)], 2.56–2.48 [m, 1 H, H2¢b(I)],
2.41–2.34 [m, 1 H, H2¢b(II)], 1.73–1.67 [m, 4 H, b¢ (I + II)],
1.13–1.05 [m, 24 H, CH3i-Pr (I + II)] ppm. 13C NMR (101
MHz, benzene-d6): 159.1, 155.6, 153.2, 144.1, 139.7, 135.6,
134.6, 130.0, 127.8, 122.3, 118.8, 116.2, 109.1, 87.6, 83.1,
70.8, 65.8, 61.7, 39.7, 34.4 ppm. 31P NMR (162 MHz,
987.4197; found: 988.7 [M + H]+.
Compound 10b: 1H NMR (400 MHz, benzene-d6): d = 7.88
[s, 1 H, H8 (I)], 7.86 [s, 1 H, H8 (II)], 7.62–6.58 [m, 52 H,
DMTr-H (I + II), Har (I + II)], 6.29–6.19 [m, 2 H, H1¢ (I +
II)], 5.76, 5.37 [2 × s, 2 × 2 H, NH (I + II)], 5.04–5.01 [m, 2
H, H3¢ (I + II)], 4.60–4.50 [m, 4 H, Ha (I + II)], 4.13–4.08
[m, 2 H, H4¢ (I + II)], 3.52–3.17 [m, 20 H, OCH3 (I + II), Hb
(I + II), H5¢ (I + II)], 2.98–2.93 [m, 1 H, H2¢a (I)], 2.89–2.84
[m, 1 H, H2¢a (II)], 2.71–2.68 [m, 8 H, i-PrH (I + II) + a¢ (I
+ II)], 2.56–2.48 [m, 1 H, H2¢b (I)], 2.41–2.34 (m, 1 H, H2¢b
(II)], 1.73–1.67 [m, 4 H, b¢ (I + II)], 1.13–1.05 [m, 24 H,
CH3i-Pr (I + II)] ppm. 13C NMR (101 MHz, benzene-d6):
20
benzol-d6): d = 149.29, 149.08 ppm. Mp 63–65 °C; [a]546
–13 (c 0.4, CHCl3). IR (KBr): 3821, 3675, 3447, 2966, 1734,
1700, 1653, 1507, 1363, 1179, 1033, 829 cm–1. MS–FAB:
m/z calcd: 1063.4510; found: 1064.7 [M + H]+.
Synlett 2008, No. 7, 1066–1070 © Thieme Stuttgart · New York

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