7
92
A. Durand and T. Brown
NH), 3056 (w, CH Ar), 2925 (m, CH ), 2844 (m, CH ), 2357 (w, C–C
2
3
alkyne), 1687 (s, CO), 1601 (m), 1503 (s, C=C Ar), 1446 (s, CH ), 1283
2
(
s), 1242 (s, C–O), 1172 (s), 1172 (s), 1086 (m), 1025 (s, C–O), 825 (m),
1
7
8
1
4
23 (m), 694 (m), 576 (s); H NMR (400 MHz, CDCl ): δ 9.40 (s, 1H),
3 H
.19 (s, 1H), 6.83–7.44 (m, 13H), 6.32 (br t, J = 6.5 Hz, 1H), 6.18 (br s,
H), 5.53 (br s, 1H), 5.37 (br s, 1H), 4.83 (br s, 1H), 4.69 ( br s, 1H),
.11 (s, 1H), 3.87 (d, J = 5.5 Hz, 2H), 3.81 (s, 3H), 3.79 (s, 3H), 3.43
(
d, J = 9 Hz, 1H), 3.33 (d, J = 8 Hz, 1H), 3.13 (br s, 2H), 2.51 (m, 1H),
2
.22–2.36 (m, 3H), 1.52 (m, 4H), 1.26 (m, 14H), 0.97–6.16 (br m, 50H);
13
C NMR (100 MHz, CDCl ): δ 207.0, 172.7, 158.8 , 147.5, 144. 7, 143.3,
3
C
1
1
5
3
2
40.0, 135.7, 135.6, 130.2, 130.2, 130.1, 129.3, 129.2 128.3, 128.2, 128.1,
27.9, 127.2, 122.6, 113.3, 86.3, 85.9, 81.6, 56.8, 56.3, 56.3, 55.4, 55.4, 55.3,
4.0, 50.2, 42.5, 41.7, 41.1, 41.0, 40.9, 39.9, 39.7, 38.7, 38.2, 37.1, 36.7, 36.4,
6.4, 36.3, 36.3, 35.9, 32.0, 31.0, 30.1, 30.0, 29.6, 29.6, 29.5, 29.4, 28.4, 28.3,
8.1, 26.9, 26.9, 25.7, 25.6, 24.4, 24.0, 24.0, 22.9, 22.7, 21.2, 19.5, 18.9, 12.0;
+
+
LRMS [ES ]: m/z 1216 (M+Na , 40%); Anal calculated: C, 73.46; H, 8.44;
N, 4.69. Found: C, 73.16; H, 8.46; N, 4.59.
ꢁ
ꢁ
5
-(12-Cholesteryloxycarbonylamino-N-(prop-2-ynyl)dodecanamido)-5 -O-(4,4 -
ꢁ
ꢁ
dimethoxytrityl)-2 -deoxyuridine-3 -O-(2-cyanoethyl-N,N-diisopropyl)phosphoramidite
7). 2-Cyanoethyl-N ,N -diisopropylchlorophosphine (61 µL, 0.28 mmol)
(
was added dropwise to a degassed solution of 6 (298 mg, 0.25 mmol)
in THF (1.5 mL) with DIPEA (109 µL, 0.62 mmol). After stirring at rt
for 0.5 hour, the solution was transferred via cannula under argon to a
separating funnel containing degassed ethyl acetate. The mixture was
washed with saturated KCl solution, dried (Na SO ) and the solvent was
2
4
removed in vacuo. Purification by column chromatography under argon
pressure (EtOAc: Hexane 4:1, 0.5% pyridine) gave 7 as a colourless air
1
sensitive foam (284 mg, 82%): H NMR (400 MHz, d -DMSO): δ 11.61 (br
6
H
s, 1H), 7.92 (br s, 1H), 6.86–7.40 (m, 14H), 6.96 (br s, 1H), 6.88 (dd, J =
1
3
3
3.6, 7.0 Hz, 1H), 5.31(br s, 1H), 4.29 (br t, J = 11 Hz, 1H), 4.02 (s, 1H),
.93 (d, J = 5.0 Hz, 1H), 3.90 (d, J = 5.0 Hz, 1H),3.74 (s, 3H), 3.73 (s,
H), 3.62 (m, 2H), 3.52 (m, 2H), 3.19 (d, J = 7.5 Hz, 2H), 3.14 (d, J = 7.5
Hz, 2H), 2.92 (q, J = 6.5 Hz, 2H), 2.75 and 2.64 (t, J = 5.8 Hz, 2H), 2.40
(m, 1H), 2.23 (m, 1H), 1.30–1.51 (m, 4H), 1.21 (m, 14H), 0.64–2.59 (br
31
+
m, 59H); P NMR (162 MHz, d -DMSO)δ 148.5, 148.9; LRMS [ES ]: m/z
6
p
+
1216 (M+Na , 40%).
Oligonucleotide Synthesis
All oligonucleotides were synthesised on an Applied Biosystems 394
automated DNA/RNA synthesiser using a standard 0.2 µmole phospho-
ramidite cycle of acid-catalysed detritylation, coupling, capping and iodine