A. Hirsch et al.
precipitate of dicyclohexyl urea (DCU) was filtered off, and the CH2Cl2
layer was washed with a saturated aqueous solution of NaHCO3 (2ꢃ
50 mL) and then dried over MgSO4. After removal of the solvent, the
crude product was purified by column chromatography (silica, CH2Cl2/
MeOH, 25:1; Rf = 0.27). Yield: 1146 mg (54%) as a white solid; 1H
7.25 (m, 44H; Bn), 7.35 (m, 24H; Bz), 7.55 (m, 12H; Bz), 7.91 (m, 16H;
Bz), 8.05 ppm (m, 8H; Bz); 13C NMR (100.6 MHz, CDCl3): d = 24.0,
25.9, 26.0, 28.8, 29.1, 29.6 (CH2), 33.1 (CH2COO), 38.9, 39.3 (CH2N), 51.8
(CH2NEDTA), 54.7 (CH2COOEDTA), 66.3, 67.7, 67.8, 68.1 (CH2-Bn), 70.7,
71.1, 71.2, 71.1, 72.5, 72.9, 73.1 (*CH), 128.0, 128.3, 128.4, 128.6, 128.7,
128.8, 130.0, 130.3, 133.6, 134.0, 134.5, 134.8 (Ph), 164.8, 164.9, 165.0,
165.5, 165.7, 165.9, 166.2, 166.3, 168.3, 168.5, 169.9, 170.1, 172.1 ppm (C=
O); MS (FAB): m/z (%): 5474 (40) [M+H]+, 4269 (35), 2736 (25), 1396
(18), 1313 (20), 548 (100); IR (KBr): n˜ = 3066, 3034, 2943, 2863, 1734,
1680, 1601, 1585, 1535, 1498, 1454, 1382, 1351, 1316, 1261, 1213, 1195,
NMR (400 MHz, CDCl3): d
= 1.43 (m, 12H; CH2), 2.13 (m, 4H;
CH2COO), 3.13 (m, 4H; CH2N), 4.62 (br, 2H; OH, CH*), 5.02 (d, 2J =
5.5 Hz, 1H; CH2-Bn), 5.05 (d, 2J = 5.5 Hz, 1H; CH2-Bn), 5.09 (d, 2J =
6.5 Hz, 1H; CH2-Bn), 5.12 (d, 2J = 6.5 Hz, 1H; CH2-Bn), 5.15 (d, 2J =
6 Hz, 1H; CH2-Bn), 5.18 (d, 2J = 6 Hz, 1H; CH2-Bn), 5.22 (d, 2J =
4 Hz, 1H; CH2-Bn), 5.24 (d, 2J = 4 Hz, 1H; CH2-Bn), 5.71 (d, 3J =
3 Hz, 1H; *CH), 5.78 (d, 3J = 3 Hz, 1H; *CH), 5.80 (d, 3J = 3 Hz, 1H;
1147, 1128, 1094, 1070, 1025 cmÀ1; UV/Vis (CH3CN): lmax (e)
= 274
(13000), 231 nm (142000); CD (CH3CN): lmax (De) = 239 (À17), 213 nm
(37); elemental analysis calcd (%) for C302H296O88N10 (5473.6): C 66.27, H
5.45, N 2.56; found: C 66.20, H 5.50, N 2.32; [a]2D0 = À51.0 (c = 0.058,
CH2Cl2).
3
3
*CH), 5.82 (d, J = 3 Hz, 1H; *CH), 5.89 (d, J = 3 Hz, 1H; *CH), 5.91
3
(d, J = 3 Hz, 1H; *CH), 6.49 (br, 1H; NH), 6.92 (br, 1H; NH), 7.09 (m,
6H; Bn), 7.15 (m, 4H; Bn), 7.28 (m, 10H; Bn), 7.40 (m, 6H; Ph), 7.56
(m, 3H; Bz), 7.91 (m, 4H; Bz), 8.01 ppm (m, 2H; Bz); 13C NMR
(100.6 MHz, CDCl3): d = 23.2, 24.0, 24.1, 25.8, 25.9, 26.0, 28.7, 28.9, 29.2
(CH2), 33.1, 33.2 (CH2COO), 38.9, 39.2, 39.3 (CH2N), 53.4, 67.7, 67.8,
67.9 (CH2-Bn), 70.7, 71.2, 71.7, 73.1 (*CH), 128.2, 128.3, 128.42, 128.47,
128.6, 128.7, 129.9, 130.0, 133.6, 133.7, 133.9, 134.4, 134.5, 134.8 (Ph),
155.9, 164.9, 165.5, 165.6, 165.7, 168.6, 169.3, 172.0, 172.1 ppm (C=O); IR
(KBr): n˜ = 3396, 3066, 2940, 1734, 1655, 1601, 1542, 1498, 1453, 1382,
1262, 1213, 1139, 1094, 1070, 1025, 962, 714, 698 cmÀ1; MS (FAB): m/z
(%): 1313 (40) [M+H]+, 925 (39), 590 (100); elemental analysis calcd
(%) for C73H72O21N2·H2O (1331.37): C 65.86, H 5.60, N 2.10; found: C
65.80, H 5.75, N 2.49; [a]2D0 = +43.0 (c = 0.108, CH2Cl2).
General procedure for the preparation of the dendritic metal complexes:
The dendrimer (0.05 mmol) was dissolved in CH2Cl2 (10 mL) or CHCl3
(10 mL) and a large excess of the metal salt (0.30 mmol) was added in
one portion. After stirring overnight at room temperature, the suspension
was filtered (Iso-Disc, 0.45 mm) to remove the uncomplexed metal salt.
After evaporation of the solvent under reduced pressure, the product
was dried in vacuo.
Compound 3-ZnCl2, ZnII-first-generation dendrimer: Compound 3-ZnCl2
was synthesized according to the general procedure from dendrimer 3
(98 mg, 0.05 mmol) and ZnCl2 (41 mg, 0.30 mmol). C,H,N elemental anal-
ysis was carried out on a sample prepared in CH2Cl2. Yield: 114 mg
(99%) as a white solid; 1H NMR (400 MHz, CDCl3): d = 2.95 (m, 2H;
Compound 3, first-generation dendrimer: Ethylenediaminetetraacetic
acid (EDTA) (915 mg, 3.13 mmol), 4-dimethylaminopyridine (DMAP)
(306 mg, 2.5 mmol), and (R,R)-dibenzyl-2-(benzoyloxy)-3-hydroxysucci-
nate[43] (6.8 g, 15.7 mmol) were suspended in CH2Cl2 (100 mL). Dicyclo-
hexyl carbodiimide (DCC) (2.6 g, 12.5 mmol) was added in one portion
at room temperature and the resulting suspension was stirred for 10 days.
The white precipitate of dicyclohexyl urea (DCU) was then filtered off,
and the organic solution was washed with saturated aqueous NaHCO3 so-
lution (2ꢃ100 mL) and with saturated NaCl solution (1ꢃ100 mL), and
then dried over MgSO4. After evaporation of the solvent under reduced
pressure, the crude product was purified by column chromatography
CH2NEDTA), 3.10 (br, 2H; CH2NEDTA), 3.70 (d, 2J
=
18 Hz, 2H;
2
2
CH2COOREDTA), 3.86 (d, J = 18 Hz, 2H; CH2COOREDTA), 3.92 (d, J =
18 Hz, 2H; CH2COOREDTA), 4.14 (d, 2J = 18 Hz, 2H; CH2COOREDTA),
4.71 (d, 2J = 12 Hz, 2H; CH2-Bn), 5.03 (d, 2J = 12 Hz, 2H; CH2-Bn),
2
3
5.16 (m, 10H; CH2-Bn), 5.25 (d, J = 12 Hz, 2H; CH2-Bn), 5.93 (d, J =
3 Hz, 2H; *CH), 5.98 (d, 3J = 3 Hz, 2H; *CH), 6.02 (d, 3J = 3 Hz, 2H;
*CH), 6.18 (d, 3J = 3 Hz, 2H; *CH), 6.90 (m, 12H; Bn), 7.29 (m, 34H;
Ph), 7.37 (m, 4H; Bz), 7.55 (m, 2H; Bz), 7.82 (m, 4H; Bz), 7.87 ppm (m,
4H; Bz); 13C NMR (100.6 MHz, CDCl3): d = 53.0 (CH2NEDTA), 56.9
(CH2COOEDTA), 68.3, 68.6, 69.0, 69.9, 70.7, 72.4, 127.9, 128.1, 128.2, 128.5,
128.6, 128.7, 128.8, 128.9, 129.2, 129.9, 130.0, 130.1, 133.7, 134.0, 134.5,
134.6 (Ph), 164.4, 164.6, 164.8, 165.3, 180.1 ppm (C=O); MS (FAB): m/z
(%): 2189 (10) [M+CsÀCl]+, 2057 (50) [MÀCl]+, 1957 (80) [MÀZnCl2],
1603 (30), 1496 (20), 992 (100); IR (KBr): n˜ = 3441, 3034, 2957, 1736,
1601, 1498, 1455, 1384, 1263, 1214, 1091, 1069, 1025, 961 cmÀ1; UV/Vis
(silica, CH2Cl2/MeOH, 40:1; Rf
= 0.68). Yield: 3370 mg (55%) as a
white solid; 1H NMR (400 MHz, CDCl3): d = 2.79 (d, 2J = 10 Hz, 2H;
CH2NEDTA), 2.81 (d, 2J = 10 Hz, 2H; CH2NEDTA), 3.55 (d, 2J = 18 Hz,
2
4H; CH2COOREDTA), 3.62 (d, J = 18 Hz, 4H; CH2COOREDTA), 4.89 (d,
2
3
2J = 12 Hz, 8H; CH2-Bn), 5.11 (d, J = 12 Hz, 8H; CH2-Bn), 5.83 (d, J
= 3 Hz, 4H; CH*), 5.90 (d, 3J = 3 Hz, 4H; *CH), 7.05 (m, 20H; Bn),
7.11 (m, 20H; Bn), 7.31 (m, 8H; Bz), 7.43 (m, 4H; Bz), 7.88 ppm (m,
8H; Bz); 13C NMR (100.6 MHz, CDCl3): d = 51.2 (CH2NEDTA), 54.3
(NCH2COEDTA), 67.8 (CH2-Bn), 71.0, 71.2 (*CH), 128.1, 128.3, 128.4,
128.6, 130.0, 133.5, 134.5, 134.8 (Ph), 165.0, 165.4, 171.1 ppm (C=O); MS
(FAB): m/z (%): 1958 (80) [M+H]+, 1867 (5) [MÀBn]+, 1495 (20), 992
(40), 978 (100) [M+H]2+; IR (KBr): n˜ = 3065, 3034, 2962, 1768, 1733,
1601, 1586, 1498, 1455, 1262, 1123, 1091, 1069 cmÀ1; UV/Vis (CH3CN):
lmax (e) = 268 (4600), 231 nm (47500); CD (CH3CN): lmax (De) = 229
(À10), 216 (À8), 202 nm (À26); elemental analysis calcd (%) for
C110H96O32N2 (1956.5): C 67.48, H 4.94, N 1.43; found: C 67.55, H 4.85, N
1.41; [a]2D0 = +30.0 (c = 1.1120, CH2Cl2).
(CH3CN): lmax (e)
= 274 (4500), 231 nm (48000); elemental analysis
calcd (%) for C110H96O32N2Cl2Zn·2CH2Cl2·H2O (2282.1): C 58.95, H 4.51,
N 1.23; found: C 58.84, H 4.47, N 0.98; [a]D20
= +54.0 (c = 0.114,
CH2Cl2).
Compound 7-ZnCl2, ZnII-second-generation dendrimer: Compound 7-
ZnCl2 was synthesized according to the general procedure from dendri-
mer 7 (30 mg, 5.5 mmol) and ZnCl2 (10 mg, 0.07 mmol). C,H,N elemental
analysis was carried out on a sample prepared in CHCl3. Yield: 30 mg
1
(99%) as a white solid; H NMR (400 MHz, CDCl3): d = 1.33 (m, 48H;
CH2), 2.10 (m, 16H; CH2COO), 2.90 (br, 4H; CH2NEDTA), 3.20 (m, 16H;
CH2N), 4.27 (m, 8H; CH2COOEDTA), 5.10 (m, 32H; CH2-Bn), 5.78 (m,
12H; *CH), 5.9 (m, 12H; *CH), 6.35 (br, 4H; NH), 6.60 (br, 4H; NH),
7.10 (m, 36H; Bn), 7.25 (m, 44H; Bn), 7.40 (m, 24H; Bz), 7.54 (m, 12H;
Bz), 7.92 (m, 16H; Bz), 8.05 ppm (m, 8H; Bz); 13C NMR (100.6 MHz,
CDCl3): d = 24.0, 24.1, 24.3, 24.5, 25.9, 26.3, 28.4, 28.9, 29.0, 29.6, 29.7
(CH2), 33.1, 33.2, 33.7, 33.9 (CH2COO), 38.7, 39.2, 39.3, 40.1 (CH2N),
51.4, 52.7, 53.4, 67.7, 67.9 (CH2-Bn), 70.7, 71.2, 71.3, 72.3, 72.8 (*CH),
128.3, 128.4, 128.5, 128.6, 128.7, 129.9, 130.0, 133.6, 133.9, 134.5, 134.8
(Ph), 165.0, 165.5, 165.7, 166.0, 166.1, 170.3, 171.8, 172.0 ppm (C=O); MS
(FAB): m/z (%): 5573 (50) [MÀCl]+, 5057 (10), 4241 (20), 2769 (18),
1313 (50), 548 (100); IR (KBr): n˜ = 2947, 1734, 1638, 1544, 1498, 1454,
1382, 1261, 1213, 1196, 1128, 1094, 1070, 1025 cmÀ1; UV/Vis (CH3CN):
lmax (e) = 274 (14000), 231 nm (145000); elemental analysis calcd (%)
for C302H296O88N10ZnCl2·3CHCl3 (5968.0): C 61.38, H 5.05, N 2.35; found:
C 61.38, H 5.07, N 2.02; [a]2D0 = À34.0 (c = 0.174, CH2Cl2).
Compound 7, second-generation dendrimer: Ethylenediaminetetraacetic
acid (EDTA) 1 (13 mg, 0.044 mmol), 4-dimethylaminopyridine (DMAP)
(9 mg, 0.077 mmol), and the second-generation dendron compound 6
(289 mg, 0.22 mmol) were suspended in dry CH2Cl2 (100 mL). 1-(3-Dime-
thylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) (72 mg,
0.375 mmol) was added and the resulting suspension was stirred for
10 days at room temperature. The white precipitate was then filtered off
and, after evaporation of the solvent under reduced pressure, the crude
product was purified by column chromatography (silica, CH2Cl2/MeOH,
25:1; Rf
= 0.68). Yield: 44 mg (18%) as a
white solid; 1H NMR
(400 MHz, CDCl3): d = 1.3 (m, 48H; CH2), 1.97 (m, 4H; CH2COO),
2.08 (m, 8H; CH2COO), 2.25 (m, 4H; CH2COO), 2.87 (m, 4H; CH2NED-
2
TA), 3.12 (m, 16H; CH2N), 3.62 (d, J = 7.5 Hz, 4H; CH2COOEDTA), 3.85
(d, 2J = 7.5 Hz, 4H; CH2COOEDTA), 5.15 (m, 32H; CH2-Bn), 5.85 (m,
24H; *CH), 6.51 (br, 4H; NH), 6.95 (br, 4H; NH), 7.10 (m, 36H; Bn),
3538
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2005, 11, 3530 – 3540