Paper
Organic & Biomolecular Chemistry
+
night, applied on a column of Dowex 50 in H form (100 ml),
IR νmax(KBr) 3311 (m, vbr), 3117 (m, br), 3022 (m, br, sh),
washed with 50% aq. ethanol (150 ml) and eluted with 3% 2749 (m, vbr), 2440 (w, vbr), 1690 (vs), 1658 (s), 1607 (m), 1580
NH in 50% aq. ethanol (300 ml). The obtained yellow solution (m, sh), 1536 (w), 1486 (w), 1415 (w), 1374 (w, br), 1117 (m),
was evaporated and purified using preparative HPLC on the 1064 (m, br), 970 (w), 779 (w), 691 (vw), 640 (vw).
reversed phase. The obtained hypoxanthine diisopropyl ester HRMS (ESI+) for C H N O PNa (M
3
+
+
Na) : calcd
1
0
15 6 5
(
80 mg, 0.2 mmol) was co-evaporated with MeCN (3 × 10 ml), 353.07338, found 353.07346.
2
0
dissolved in the same solvent, and Me
3
SiBr (0.13 ml, 1 mmol)
2
[α] = +48.8 (c 0.172, H O).
was added under an argon atmosphere. The reaction mixture
was stirred under an argon atmosphere at rt overnight. The
title compound was obtained by preparative reverse phase
[
3S,4S] Diisopropyl 1-N-tert-butyloxycarbonyl-4-
dimethoxytrityloxypyrrolidin-3-yloxymethylphosphonate 18
HPLC in 10% overall yield (21.8 mg, 65 μmol) – calculated [3S,4S]-1-N-Boc-3-dimethoxytrityloxy-4-hydroxypyrrolidine
from 31 – after conversion to sodium salt by passing through a (12 g, 34.42 mmol) diisopropyl tosyloxymethanephosphonate
+
column of Dowex 50 in Na form and lyophilisation from water (17.19 g, 49 mmol) was dissolved in THF (300 ml). The solu-
in the form of a white amorphous solid.
tion was cooled to 0 °C and sodium hydride (2.8 g, 70 mmol)
O, 25 °C): 3.60 (dd, 1H, Jgem = 12.1, was added. The reaction mixture was stirred at rt for 3 days
P); 3.69 (dd, 1H, Jgem = 12.1, JH,P = 9.5, and then cooled to 0 °C and acetic acid (1.8 ml, 29 mmol) was
CH H P); 3.76 (dt, 1H, J = 13.3, J2′b,3′ = J2′b,4′ = 1.2, H-2′b); added slowly. The temperature was allowed to rise to rt and
1
H NMR (600.1 MHz, D
H,P = 10.0, CH
2
J
a b
H
a
b
gem
3
.84 (dd, 1H, Jgem = 13.3, J2′a,3′ = 4.2, H-2′a); 4.07 (dd, 1H, Jgem
=
the solvent was evaporated in vacuo. The title compound was
1
3.6, J5′b,4′ = 3.2, H-5′b); 4.15 (dd, 1H, Jgem = 13.6, J5′a,4′ = 7.7, obtained by chromatography on silica gel using a linear gradi-
H-5′a); 4.51 (dt, 1H, J3′,2′ = 4.2, 1.2, J3′,4′ = 1.2, H-3′); 5.47 (ddt, ent of ethyl acetate in toluene as a viscous colorless oil in 77%
1
8
H, J4′,5′ = 7.7, 3.2, J4′,3′ = J4′,2′b = 1.2, H-4′); 8.18 (s, 1H, H-2); yield (14.5 g, 22.11 mmol).
.25 (s, 1H, H-8).
1
3
NMR – (1 : 1 mixture of amide rotamers)
C NMR (150.9 MHz, D O, 25 °C): 50.33 (CH -5′); 52.42
2
2
1
(CH
2
-2′); 62.19 (CH-4′); 69.49 (d, JC,P = 152.9, CH
2
P); 86.50 (d,
H NMR (500.0 MHz, CDCl
3
, 25 °C): 1.24, 1.27, 1.28, 1.29 (4 ×
CH); 1.41, 1.46 (2 × s, 2 × 9H,
= 12.0, H-5b); 3.07 (dd, 1H, J3,4
JC,P = 13.3, CH-3′); 126.74 (C-5); 144.33 (CH-8); 148.42 (CH-2); d, 4 × 6H, Jvic = 6.2, (CH
3 2
)
1
51.25 (C-4); 161.39 (C-6). (CH ) C); 2.92 (d, 1H, J
=
3
3
gem
3
1
1
P{ H} NMR (202.3 MHz, D
IR νmax(KBr) 3434 (vs, br), 3264 (m, br, sh), 2923 (m), 2853 3.25, 3.29 (2 × dd, 2 × 1H, Jgem = 13.4, JH,P = 9.7, CH
m), 2790 (m, vbr, sh), 1695 (s), 1588 (m), 1550 (w), 1515 (w), 3.30–3.33 (m, 3H, H-3,5); 3.34 (dd, 1H, Jgem = 13.2, JH,P = 9.7,
470 (w, sh), 1418 (w), 1382 (vw), 1346 (vw), 1216 (w), 1190 (w, CH P); 3.37, 3.41 (2 × d, 2 × 1H, Jgem = 12.1, H-2b); 3.42 (dd,
br), 1146 (w, vbr), 1112 (w, sh), 1051 (m, br), 912 (w, br), 896 1H, Jgem = 13.2, JH,P = 9.7, CH P); 3.49, 3.56 (2 × dd, 2 × 1H,
w, sh), 790 (w), 646 (w). Jgem = 12.1, J2a,3 = 4.1, H-2a); 3.786, 3.789 (2 × s, 2 × 6H,
HRMS (ESI-) for C10 P (M − H) : calcd 314.06598, CH O-DMTr); 4.10 (bt, 2H, J4,3 = J4,5a = 4.7, H-4); 4.60–4.70 (m,
found 314.06585. 4H, CH(CH ); 6.83, 6.84 (2 × m, 2 × 4H, H-m-C -DMTr);
7.13–7.36 (m, 14H, H-o-C H -DMTr, H-m,p-C H -DMTr); 7.43
2
O, 25 °C): 13.57.
4.7, J3,2a = 4.1, H-3); 3.08 (dd, 1H, Jgem = 12.0, J5a,4 = 4.7, H-5a);
2
P);
(
1
a b
H
a
H
b
(
−
H
13
N
5
O
5
3
3
)
2
6 4
H
2
0
[
α] = −30.4 (c 0.184, H O).
2
6
4
6
5
(
m, 4H, H-o-C
6
H
5
-DMTr).
1
3
C NMR (125.7 MHz, CDCl
3
, 25 °C): 23.85, 23.97, 24.01 (d,
[
3R,4R]-(4-(Guanin-9-yl)pyrrolidin-3-yl)oxymethanephosphonic
JC,P = 4.0, (CH ) CH); 28.39, 28.45 ((CH ) C); 48.68, 49.48 (CH -
3 2
3 3
2
acid 16c
2
2 3
); 50.72, 50.82 (CH -5); 55.17 (CH O-DMTr); 63.92, 64.03 (d,
The title compound was prepared from amino derivative 31
2
JC,P = 170.0, CH P); 70.95, 71.03, 71.05, 71.13 (d, JC,P = 7.0, CH
(
0.23 g, 0.61 mmol) and 2-amino-4,6-dichloro-5-formamidopyr- (CH ) ); 74.27, 75.06 (CH-4); 79.14, 79.24 (C(CH ) ); 83.65,
3
2
3
3
imidine (33) (0.15 g, 0.73 mmol) using the same procedure as 84.37 (d, JC,P = 13.0, CH-3); 87.10, 87.25 (C-DMTr); 113.22,
for compound 16b in 8% overall yield (17.3 mg, 49 µmol) in 113.25 (CH-m-C -DMTr); 126.99 (CH-p-C -DMTr); 127.91
the form of a white amorphous solid. (CH-m-C H -DMTr); 128.18, 128.21 (CH-o-C H -DMTr); 130.10,
6
H
4
6 5
H
6
5
6
5
1
H NMR (500.0 MHz, D
2′b,3′ = J2′b,4′ = 1.4, H-2′b); 3.71 (dd, 1H, Jgem = 12.5, JH,P = 9.9, DMTr); 144.97, 145.03 (C-i-C
CH H P); 3.79 (dd, 1H, J = 12.5, JH,P = 9.6, CH H P); 3.90 158.67, 158.70 (C-p-C H -DMTr).
2
O, 25 °C): 3.71 (dt, 1H, Jgem = 13.3, 130.14 (CH-m-C
6
H
4
-DMTr); 136.11, 136.20, 136.30 (C-i-C
6 4
H -
J
6 5
H
-DMTr); 154.54, 154.66 (CO);
a
b
gem
a
b
6
4
3
1
1
(
1
dd, 1H, Jgem = 13.3, J2′a,3′ = 4.6, H-2′a); 4.04 (dd, 1H, Jgem
3.5, J5′b,4′ = 3.4, H-5′b); 4.08 (dd, 1H, Jgem = 13.5, J5′a,4′ = 6.7,
H-5′a); 4.52 (ddd, 1H, J3′,2′ = 4.6, 1.4, J3′,4′ = 1.9, H-3′); 5.29 (m, 706.3121, found 706.3146.
=
P{ H} NMR (202.3 MHz, CDCl
3
, 25 °C): 19.00, 19.05.
+
HRMS (FAB+) for C37 PNa (M + H + Na) : calcd
H50NO
9
1
H, H-4′); 7.89 (s, 1H, H-8).
1
3
[3S,4S] Diisopropyl 1-N-tert-butyloxycarbonyl-4-
hydroxypyrrolidin-3-yloxymethylphosphonate 19
C NMR (125.7 MHz, D
2 2
O, 25 °C): 50.19 (CH -5′); 52.53
(CH -2′); 61.61 (CH-4′); 68.89 (d, J = 155.7, CH P); 86.68 (d,
2
C,P
2
JC,P = 13.1, CH-3′); 119.04 (C-5); 141.77 (CH-8); 153.73 (C-4); 2% TFA in DCM (200 ml) was added to compound 18 (14.5 g,
1
56.3 (C-2); 161.56 (C-6).
22.11 mmol) and the reaction mixture was stirred until the
DMTr group was cleaved completely (followed by TLC,
3
1
1
P{ H} NMR (202.3 MHz, D O, 25 °C): 14.71.
2
4702 | Org. Biomol. Chem., 2015, 13, 4693–4705
This journal is © The Royal Society of Chemistry 2015