A R T I C L E S
Park et al.
5.11 (1H, s), 4.94 (1H, dd, J ) 2.3), 4.17 (1H, dd, J ) 2.3), 3.51 (1H,
br s), 3.14 (2H, quartet, J ) 6.5), 1.50 (3H, s), 1.46-1.39 (2H, m),
1.30 (3H, s), 1.33-1.24 (2H, m), 0.87 (3H, t, J ) 7.4); 13C NMR (100
MHz, DMSO-d6) δ 155.5, 149.2, 137.7, 120.0, 113.6, 90.2, 87.6, 84.7,
82.0, 62.1, 40.8, 32.0, 27.7, 25.9, 20.1, 14.3; MS m/z (ESI) 423.2006
[(M + H)+, C18H27N6O6 requires m/z 423.1992].
mixture. To the homogeneous mixture was added dropwise 200 mL of
H2O precipitating crude product which was collected by filtration,
washed with ethanol, ethyl acetate, diethyl ether, and pentane to afford
8.4 g (99%) of 7 as a fine, white powder, mp 242-243 °C (CH3OH);
1H NMR (400 MHz, DMSO-d6) δ 11.91 (1H, s), 9.95 (1H, s), 8.14
(1H, s), 6.93 (1H, t, J ) 5.6), 5.71 (1H, d, J ) 5.6), 5.45 (1H, d, J )
5.9), 5.15 (1H, d, J ) 4.9), 5.01 (1H, t, J ) 5.0), 4.39 (1H, dd, J )
5.0), 4.09 (1H, dd, J ) 4.3), 3.88 (1H, dd, J ) 3.5), 3.66-3.58 (1H,
m), 3.56-3.49 (1H, m), 3.13 (2H, qu, J ) 6.6), 1.46-1.39 (2H, m),
1.33-1.24 (2H, m), 0.87 (3H, t, J ) 7.4); 13C NMR (100 MHz, DMSO-
d6) δ 155.8, 155.6, 149.8, 149.4, 137.8, 119.2, 87.6, 85.9, 74.6, 70.8,
61.8, 39.4, 31.9, 20.0, 14.3. MS m/z (ESI) 383.1691 [(M + H)+
C15H23N6O6 requires m/z 383.1679].
2′,3′,5′-O-Acetyl Guanosine (5). By use of a modified procedure
of that reported,14 20 mL (200 mmol) of acetic anhydride was added
dropwise to a mixture of 19.1 g (67.5 mmol) of guanosine, 56.5 mL
(405 mmol) of triethylamine, and 860 mg (7.0 mmol) of N,N-
(dimethylamino)pyridine in 250 mL of CH3CN at 0 °C. The mixture
was stirred for 1 h and warmed to room temperature and stirred for 3
h. The reaction was quenched with 20 mL of methanol. The volume
was reduced to 100 mL at reduced pressure, and diethyl ether was added
dropwise for over 1 h to induce precipitation of a fine, white powder,
which was collected by filtration and washed with diethyl ether. The
powder was slurried in 250 mL of acetone and stirred at 50 °C for ca.
5 h. Filtration afforded 28.6 g (99%) of 5 as a fine white powder, mp
228-229 °C (CH3CN); 1H NMR (400 MHz, DMSO-d6) δ 10.74 (1H,
s), 7.92 (1H, s), 6.53 (2H, s), 5.96 (1H, d, J ) 6.5), 5.76 (1H, t, J )
5.5), 5.47 (1H, t, J ) 5.5), 4.35 (1H, dd, J ) 4.0, 10.0), 4.29 (1H, dt,
J ) 4.0, 10.0), 4.23 (1H, dd, J ) 4.0, 10.8). All other physical and
spectroscopic data was identical to that previously reported.14
UG-Dye343 Conjugate (18). A mixture of 57 mg (0.2 mmol) of
coumarin 343, 51 mg (0.26 mmol) of EDCI, and 12 mg (0.04 mmol)
of DPTS (DMAP-p-toulenesulfonic acid complex) in 10 mL of DMF
was stirred at room temperature for 1 h. A solution of 84.4 mg (0.2
mmol) of 7 in 5 mL of DMF was added, and the mixture was stirred
at room temperature for 15 h. The solvent was removed by a rotary
evaporator equipped with high vacuum and the residue dissolved in
20 mL of chloroform. The solution was washed with 20 mL of H2O,
and the aqueous layer was extracted three times with 20 mL of CHCl3.
The combined organic layers were washed with 20 mL of brine, dried
over MgSO4, filtered, and the solvent removed with rotary evaporator.
The crude material was purified by column chromatography (SiO2, Rf
) 0.30, 95:5 CHCl3:CH3OH) to give 68 mg (50%) of 18 as an orange
solid: 1H NMR (500 MHz, CDCl3) δ 12.23 (1H, s), 10.25 (1H, s),
8.24 (1H, s), 7.97 (1H, s), 7.27 (1H, s), 6.89 (1H, s), 6.06 (1H, s), 5.33
(1H, d, J ) 5.9), 5.23 (1H, dd, J ) 2.4), 4.88 (1H, dd, J ) 2.4), 4.94
(1H, dd, J ) 5.9), 4.62 (1H, dd, J ) 2.4), 3.33-3.27 (6H, m), 2.77-
2.69 (4H, m), 1.93 (4H, m), 1.58 (3H, s), 1.55 (2H, t, J ) 7.5), 1.38
(2H, t, J ) 7.5), 1.33 (3H, s), 0.92 (3H, t, J ) 7.4); 13C NMR (125
MHz, CDCl3) δ 164.9, 159.4, 155.2, 153.8, 150.2, 149.8, 149.6, 148.65,
138.1, 127.7, 120.3, 120.2, 114.3, 107.9, 105.7, 104.8, 91.2, 85.8, 85.3,
81.8, 64.0, 50.6, 50.1, 40.0, 32.0, 27.5, 27.3, 25.5, 21.1, 20.3, 20.2,
14.0. MS m/z (ESI) 690.2894 [(M + H)+ C34H40N7O9 requires m/z
690.2888].
Acetic Acid 3,4-Diacetoxy-5-[2-(3-butylureido)-6-oxo-1,6-dihydro-
purin-9-yl]-tetrahydro-furan-2-yl Methyl Ester (UG, 6). To a
solution of 18.25 g (44.7 mmol) of 5 in 300 mL of DMF at 0 °C was
added 1.7 g (42 mmol) of NaH (60% dispersion in mineral oil). The
solution was slowly warmed to 70 °C and stirred for 2 h. The mixture
was cooled to 0 °C, and 4.9 mL (44 mmol) of butylisocyanate was
added. After 1 h, ca. 10 mL of a 5% (w/v) aqueous solution of
hydrochloric acid was added to the mixture. The DMF was removed
using a rotary evaporator equipped with high vacuum. The resulting
solid was ground to a powder, washed with H2O, and dissolved in 200
mL of CHCl3. The solution was washed with water, and the aqueous
layer was extracted with CHCl3. The combined organic layers were
washed with 200 mL of brine, dried over MgSO4, and filtered.
Removing the solvent in vacuo afforded 20.9 g (97%) of 6 as a white,
fine powder, which was sufficiently pure to use in the next reaction.
Further purification could be achieved by column chromatography
(SiO2, Rf ) 0.31, 93:7 CHCl3:CH3OH), mp 103-105 °C (CHCl3); 1H
NMR (400 MHz, CDCl3) δ 12.65 (1H, s), 10.37 (1H, s), 7.93 (1H, s),
7.34 (1H, s), 6.07 (1H, t, J ) 9.4), 6.01 (1H, t, J ) 5.1), 5.60 (1H, br
t, J ) 9.4), 4.37 (1H, dd, J ) 7.6), 4.37 (1H, s), 4.23 (1H, dd, J )
7.6), 3.30 (2H, quartet, J ) 6.4), 2.10 (3H, s), 2.07 (3H, s), 1.99 (3H,
Acknowledgment. Funding of this work by the NSF (CHE-
0212772) and by the U.S. Department of Energy, Division of
Materials Science, under Award No. DEFG02-91ER45439
through the Frederick Seitz Materials Research Laboratory at
the University of Illinois at Urbana-Champaign is gratefully
acknowledged. S.N. gratefully acknowledges the Japanese
Society for the Promotion of Science (JSPS) for a postdoctoral
fellowship.
s), 1.60-1.52 (2H, m), 1.41-1.32 (2H, m), 0.93 (3H, t, J ) 7.6); 13
C
NMR (100 MHz, CDCl3) δ 177.8, 169.9, 169.9, 157.019, 155.6, 150.4,
149.5, 138.3, 120.7, 87.0, 80.3, 72.3, 70.9, 63.1, 40.0, 31.9, 20.8, 20.7,
20.7, 20.1, 13.9; MS m/z (ESI) 509.2013 [(M + H)+, C21H29N6O9
requires m/z 509.1996]. Anal. Calcd. for C21H28N6O9: C, 49.60; H,
5.55; N, 16.53. Found C, 49.50; H, 5.60; N, 16.05.
1-Butyl-3-[9-(3,4-dihydroxy-5-hydroxymethyl-tetrahydro-furan-
2-yl)-6-oxo-6,9-dihydro-1H-purin-2-yl]-urea (UG, 7). To a solution
of 11.3 g (22.3 mmol) of 6 in 100 mL of CH3OH at room temperature
was added 5.42 g (100 mmol) of sodium methoxide producing a white
precipitate. The mixture was stirred for 10 h at room temperature and
ca. 10 mL of a 5% (w/v) aqueous solution of HCl was added to the
Supporting Information Available: General experimental
details, detailed synthetic procedures and characterization data
for compounds 11-17, details on the X-ray analysis of 6
including a cif file, and additional experimental details on
computational and complexation studies. This material is
JA0545517
9
18142 J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005