MONOMERS FOR OLIGONUCLEOTIDE SYNTHESIS…I.
231
1
triethylamine (5.15 ml, 36.8 mmol) were successively
added to an ice-cooled suspension of 1,2,4-triazole
(2.54 g, 36.8 mmol) in dry acetonitrile (50 ml). The sus-
pension was stirred for 30 min, treated with the nucleo-
side solution in acetonitrile, and then stirred for 1.5 h at
room temperature, and evaporated. The residue was
dissolved in methylene chloride (100 ml); the solution
was washed with 5% NaHCO3 (50 ml) and water
(50 ml), dried with Na2SO4, and evaporated. The resi-
due was dissolved in acetonitrile (20 ml), and 1,3-
diaminopropane (1.54 ml, 18.4 mmol) was added. After
1 h, 10 ml of concentrate ammonia was added to the
reaction mixture, and it was kept overnight at room
temperature and evaporated. The residue was dissolved
in methylene chloride (100 ml), washed with 0.1 M
NaOH (30 ml) and water (5 × 50 ml), dried with
Na2SO4, and evaporated. The residue was dissolved in
methylene chloride (5 ml), and the product (XVIII)
was precipitated with hexane; yield: 0.9 g (1.5 mmol,
81%); Rf 0.14 (7 : 2 : 1 methylene chloride–methanol–
chloride–methanol); H NMR ((CD3)2SO): 8.64 (3 H,
br t, CH2NHC(O)), 8.45 (1 H, br t, CH2NHC(O)), 7.69
(1 H, s, H6), 6.14 (1 H, quasi-triplet, J 6.4, H1'), 4.22 (1
H, m, H3'), 4.16 (2 H, s, CH2O), 4.11 (1 H, m, H4'),
3.79 (6 H, s, OCH3), 3.62 (4 H, m, H5', OCH2CH2),
3.41–3.11 (8 H, m, CH2CH2CH2NH and CH2CH2N ),
2.60 (6 H, m, CH2CH2N ), 2.22–1.88 (2 H, m, H2'),
and 1.72 (2 H, m, CH2CH2CH2).
N4-Benzoyl-5-{3-[N,N-bis(2-methoxyoxalylamido-
ethyl)aminoethyl]amidooxalylamidopropyl}oxyme-
thyl-2'-deoxycytidine (XIV). Benzoic anhydride
(0.181 g, 0.8 mmol) was added to a solution of 0.6 g
(0.87 mmol) of (XIII) in DMF (4 ml). The reaction
mixture was kept for 16 h at room temperature and
treated with additional benzoic anhydride (18 mg).
After 1 h at 45°ë, the mixture was evaporated. The res-
idue was triturated with ether (3 × 5 ml) and dried in a
vacuum to give (XIV); yield 0.4 g (0.5 mmol, 58%); Rf
1
0.45 (4 : 1 methylene chloride–methanol); H NMR
1
(C5D5N): 9.35–9.07 (4 H, m, CH2NHC(O)), 8.53 (2 H,
m, Bz), 8.47 (1 H, s H6), 7.50 (3 H, m, Bz), 6.85 (1 H,
quasi-triplet, J 6.1, H1'), 5.02 (1 H, m, H3'), 4.60 (1 H,
d, J 12.0, CHaHbO), 4.48 (1 H, d, J 12.0, CHaHbO), 4.46
triethylamine); H NMR (CDCl3): 7.58 (1 H, s, H6),
7.42–7.11 [9 H, m, (MeO)2Tr], 6.80 [4 H, d, J 8.0,
(MeO)2Tr], 6.43 (1 H, quasi-triplet, J 6.1, H1'), 4.50 (1
H, m, H3'), 4.04 (1 H, m, H4'), 3.77 (6 H, s, OCH3),
3.72 (1 H, m, NHCH2), 3.62 (2 H, m, NHCH2CH2),
(1 H, m, H4'), 4.26 (1 H, dd, 2J 12.0, J 3.0, H5'), 4.09
(1 H, dd, J 2.9, H5'), 3.78 (8 H, m, OCH3, OCH2CH2),
3.68–3.42 (8 H, m, CH2CH2CH2NH and ëH2CH2N ),
2.88–2.55 (8 H, m, CH2CH2N and H2'), and 1.96
(2 H, m, CH2CH2CH2).
2
3.44 (1 H, dd, J 10, J 3.0, H5'), 3.30 (1 H, dd, J 2.9,
H5), 2.87 (2 H, t, J 5.9, CH2CH2NH2), 2.54 (1 H, m,
'
'
H2a ), 2.20 (1 H, m, H2b ), 1.70 (2 H, m, CH2CH2CH2),
and 1.46 (3 H, s, CH3).
N4-Benzoyl-5-{3-[N,N-bis(2-methoxyoxalylamido-
ethyl)aminoethyl]amidooxalylamidopropyl}oxyme-
thyl-5'-O-(4,4'-dimethoxytrityl)-2'-deoxycytidine (XV)
was obtained from (XIV) by the above-described pro-
cedure, using 10% methanol as the final eluting solvent;
yield 0.27 g (0.27 mmol, 62%); Rf 0.28; H NMR
(CDCl3): 8.20 (2 H, d, J 6.9, Bz), 7.91 (2 H, m, H6,
N4-{3-[N,N-Bis(2-methoxyoxalylamidoethyl)ami-
noethyl]amidooxalylamidopropyl}-5'-O-(4,4'-dime-
thoxytrityl)-5-methyl-2'-deoxycytidine (XIX) was
obtained from (XVIII) by the above-described proce-
dure, using 12% final concentration of methanol in the
eluting solution; yield 41%; Rf 0.18; 1H NMR (CDCl3):
8.05 (1 H, t, J 6.1, CH2NHC(O)), 7.70(3 H, m,
CH2NHC(O)), 7.61 (1 H, s, H6), 7.52–7.15 [9 H, m,
(MeO)2Tr), 6.80 [4 H, d, J 8.2, (MeO)2Tr), 6.43 (1 H,
quasi-triplet, J 6.4, H1'), 5.94 (1 H, br t, J 6.1,
NHCH2CH2CH2), 4.50 (1 H, m, H3'), 4.04 (1 H, m,
H4'), 3.82 (6 H, s, OCH3), 3.77 (6 H, s, OCH3), 3.58–
3.27 (12 H, m, H5, NHCH2CH2CH2, CH2CH2CH2NH,
and CH2CH2N ), 2.75–2.60 (6 H, m, CH2CH2N ),
1
CH2NHCO), 7.68 (2 H, quasi-triplet,
J
6.5,
CH2NHC(O)), 7.58–7.12 (13 H, m, MeO)2Tr,
CH2NHC(O) and Bz), 6.80 (4 H, d, (MeO)2Tr), 6.35
(1H, quasi-triplet, J 6.4, H1'), 4.55 (1 H, m, H3'), 4.13
(2 H, s, CH2O), 4.05 (1 H, m, H4'), 3.81 (6 H, s, OCH3),
3.76 (8 H, m, OCH3, OCH2CH2), 3.60–3.13 (10 H, m,
H5, CH2CH2CH2NH and CH2CH2N ), 2.79–2.36 (8 H,
m, CH2CH2N and H2'), 1.68 (2 H, m, CH2CH2CH2).
N4-(3-Aminopropyl)-5'-O-(4,4'-dimethoxytrityl)-
5-methyl-2'-deoxycytidine (XVIII). Trimethylchlo-
rosilane (0.47 ml, 3.7 mmol) was added to a stirred
'
'
2.52 (1 H, m, H2a), 2.22 (1 H, m, H2b), 1.84 (2 H, m,
CH2CH2CH2), and 1.54 (3 H, s, CH3).
N6-(1,2,4-Triazole-4-yl)-2'-deoxyadenosine (XXII).
Trimethylchlorosilane (0.5 ml, 4 mmol) and 1,2-
bis[(dimethylamino)methylene]hydrazine (1.11 g,
7.8 mmol) were added to a solution of 2'-deoxyadenos-
ine (XXI) (0.5 g, 2 mmol) in dry pyridine (5 ml). The
reaction mixture was refluxed for 5 h and kept for 16 h
at room temperature. An additional quantity of trimeth-
solution
of
5'-O-(4,4'-dimethoxytrityl)thymidine
(XVII) (1 g, 1.84 mmol) in dry pyridine (5 ml). After
30 min, the reaction mixture was evaporated, the oil
was dissolved in methylene chloride (100 ml), and the
solution was washed with 5% NaHCO3 (50 ml) and
water (50 ml). The organic layer was dried with
Na2SO4, evaporated, coevaporated with toluene to
remove pyridine (3 × 10 ml), dissolved in dry acetoni- ylchlorosilane (0.5 ml) was added to the reaction mix-
trile (5 ml), and mixed with triethylamine (0.5 ml). Sep- ture, and after 20 min the solution was diluted with
arately, phosphoryl chloride (0.69 ml, 7.36 mmol) and methylene chloride (20 ml) and extracted with 1 N HCl
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 30 No. 3 2004