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Can. J. Chem. Vol. 82, 2004
aqueous sodium hydroxide solution, keeping the temperature
below 2 °C, which gave a purplish-red precipitate. After all
the diazonium salt solution had been added, the reaction
mixture was allowed to stand in an ice bath for 1 h with stir-
ring. The resulting precipitate was filtered and washed with
cold water several times to remove residual DMF. The
unreacted naphthol AS in the crude product was removed by
soxhlet extraction with acetonitrile to give 0.48 g of pure
product (39% yield, mp 216–218 °C).
The diazo-coupling reaction with other couplers (naphthol
AS-RL, naphthol AS-BG, and naphthol AS-BS) was carried
out by same method as above. Naphthol AS-RL azo deriva-
tive (4; 10% yield, mp > 250 °C); naphthol AS-BG azo de-
rivative (5; 10% yield, mp 182–184 °C); naphthol AS-BS
azo derivative (6; 14% yield, mp 188–190 °C). The diazo
coupling reaction between higher generations of the
aminophenyl derivative of the dendrimer (2G, 3G, and 4G)
and naphthol AS was carried out by same method as above.
2G (20% yield, mp 178–180 °C); 3G (12% yield, mp 207–
209 °C); 4G (14% yield, mp 211–213 °C). The characteris-
tics of the phenylazo derivatives of the PAMAM dendrimers
are as follows:
8.0 (H6′, bs), 7.9 (inner amide NH), 7.8 (H3′′, bs), 7.7 (H7,
bt), 7.4 (H6, bt), 7.2 (H3′, d), 7.1 (H4′, d), 6.9 (H2′′, bs), 4.1
(NH, bs), 3.8 (OCH3, bs), 3.2 (Hg, Hc, bs), 3.0 (Hh, bs), 2.6
(Hd, bs), 2.4 (He, Ha, bs), 2.2 (Hf, Hb, bs). 13C NMR
(DMSO-d6) δ: 172.0 (C=O-outer), 171.4 (C=O-inner), 162.0
(C=O-phenyl), 161.5 (C2), 153.0 (C5′), 148.8 (C1′′), 142.8
(C2′′), 139.7 (C4′′), 138.3 (C4), 134.5 (C1), 131.0 (C5), 130.5
(C7), 130.0 (C10), 128.7 (C1′), 125.7 (C6), 125.6 (C3), 125.6
(C9), 122.4 (C3′′), 120.8 (C8), 113.9 (C2′′), 11.4 (C3′), 107.2
(C4′), 106.9 (C6′), 56.3 (OCH3 at C2′), 55.0 (OCH3 at C5′),
50.3 (Cd), 49.4 (Ca, Ce), 44.2 (Cg), 44.0 (Ch), 37.0 (Cc), 32.9
(Cb, Cf).
R = 3′-nitro, 6–1G: IR (KBr disk) (cm–1): 3309, 2944,
1656, 1604, 1535, 1262, 1072, 806, 738, 464. 1H NMR
(DMSO-d6) δ: 12.4 (OH, s), 11.4 (amide NH, s), 8.5 (H4,8
,
broad s), 8.2 (H5, broad s), 8.1 (outer amide NH, s), 8.0 (H6′,
bs), 7.9 (inner amide NH), 7.8 (H3′′, bs), 7.7 (H7, bt), 7.4
(H6, bt), 7.2 (H3′, d), 7.1 (H4′, d), 6.9 (H2′′, bs), 4.1 (NH, bs),
3.8 (OCH3, bs), 3.2 (Hg, Hc, bs), 3.0 (Hh, bs), 2.6 (Hd, bs),
2.4 (He, Ha, bs), 2.2 (Hf, Hb, bs).
Model phenylazo derivatives of PAMAM dendrimers
The model compounds 7 and 8 were synthesized by the
same method as that used for the dendrimer. 7 (29% yield,
mp 224 to 225 °C); 8 (32% yield, mp 214 to 215 °C). The
characteristics of the model compounds (7 and 8) are as fol-
lows:
3–6
R = H, 3–1G: IR (KBr disk) (cm–1): 3189, 2922, 2853,
1736, 1662, 1660, 1539, 1444, 1264, 1174, 1017, 808, 752,
1
692, 515. H NMR (DMSO-d6) δ: 12.4 (OH, s), 11.3 (amide
NH, s), 8.6 (H4,8, bs), 8.2 (H5, amide NH, bs), 7.8 (H3′′, H2′,
H7, inner amide NH, bt), 7.4 (H6, H3′, bt), 7.1 (H4′, dd), 6.6
(H2′′, d), 3.8 (NH, bs), 3.2 (Hg, Hc, bs), 2.9 (Hh, bs), 2.7 (Hd,
bs), 2.4 (He, Ha, bs), 2.1 (Hf, Hb, bs). 13C NMR (DMSO-d6)
δ: 171.6 (C=O-outer), 170.9 (C=O-inner), 162.0 (C=O-
phenyl), 161.5 (C2), 150.4 (C1′′), 138.9 (C4), 138.3 (C1′),
138.1 (C4′′), 133.9 (C1), 133.6 (C10), 129.5 (C5), 129.5 (C7),
128.4 (C3′), 125.5 (C3, C9), 124.6 (C6), 123.3 (C4′), 121.5
(C3′′), 120.3 (C8), 119.7 (C2′′), 112.4 (C2′′), 52.0 (Cd), 49.5
(Ce), 49.3 (Ca), 43.4 (Cg), 42.3 (Ch), 36.8 (Cc), 33.2 (Cb, Cf).
MS m/z (ES) calcd. for C161H167N36O19: 3234.4; found:
2978.5.
7, 8
R = H (7): IR (KBr disk) (cm–1): 3343, 2922, 2853, 1736,
1662, 1660, 1539, 1444, 1264, 1174, 1017, 808, 752, 692,
515. H NMR (DMSO-d6) δ: 12.48 (OH, s, 1H), 11.30 (am-
1
ide NH, s, 1H), 8.60 (H4, d, 1H), 8.60 (H8, d, 1H), 7.98 (H5,
d, 1H), 7.82 (H3′′, d, 2H), 7.80 (H2′, d, 2H), 7.67 (H7, t, 1H),
7.46 (H6, t, 1H), 7.39 (H3′ dd, 2H), 7.13 (H4′, dd, 1H), 6.80
(NH, d, 1H), 6.73 (H2′′, d, 2H), 2.99 (CH3, s, 3H). 13C NMR
(DMSO-d6) δ: 162.7 (C=O), 161.8 (C2), 152.0 (C1′′), 138.7
(C1′), 138.4 (C4), 134.3 (C4′′), 133.6 (C10), 129.9 (C7), 129.9
(C5), 128.9 (C3′), 128.6 (C9), 125.9 (C1), 125.9 (C3), 125.0
(C6), 123.7 (C4′), 122.4 (C3′′), 120.8 (C8), 119.8 (C2′), 112.3
(C2′′), 29.14 (CH3). MS m/z (ES+): 397. 3 ([M + 1]). MS
m/z (high-resolution EI) calcd. for C24H20N4O3: 396.1586;
found: 396.1598. Anal. calcd. for C24H20N4 (MW 396.16): C
72.73, H 5.05, N 14.14; found: C 72.21, H 4.98, N 14.08.
Azo naphthol AS derivative of the PAMAM dendrimer -2G
(3–2G): IR (KBr disk) (cm–1): 3246, 2928, 1655, 1597,
1549, 1445, 1384, 1199.
Azo naphthol AS derivative of the PAMAM dendrimer -3G
(3–3G): IR (KBr disk) (cm–1): 3253, 2927, 1654, 1596,
1550, 1384, 1199, 1147.
R = 4′-methoxy (8): IR (KBr disk) (cm–1): 3340, 3021,
2879, 1735, 1660, 1658, 1540, 1450, 1258, 1170, 1015, 809,
690. H NMR (DMSO-d6) δ: 12.48 (OH, s, 1H), 11.12 (am-
Azo naphthol AS derivative of the PAMAM dendrimer -4G
(3–4G): IR (KBr disk) (cm–1): 3270, 2935, 1658, 1596,
1550, 1447, 1384, 1199.
R = 4′-methoxy, 4–1G: IR (KBr disk) (cm–1): 3332, 3077,
2963, 1666, 1604, 1547, 1512, 1262, 1069, 806, 696, 462.
1H NMR (DMSO-d6) δ: 12.5 (OH, s), 11.4 (amide NH, s),
8.6 (H4, H8, bs), 8.3 (H5, bs), 8.2 (outer amide NH, s), 7.9
(H3′′, bs), 7.8 (H2′, H7, bt), 7.2 (H6, bt), 7.1 (H3′, d), 6.7
(H2′′, d), 4.2 (NH, bs), 3.6 (OCH3, s), 3.2 (Hg, Hc, bs), 2.9
(Hh, bs), 2.6 (Hd, He, Ha, bs), 2.2 (Hf, Hb, bs).
1
ide NH, s, 1H), 8.57 (H8, d, 1H), 8.56 (H4, s, 1H), 7.95
(H5,d, 1H), 7.80 (H3′′, d, 2H), 7.70 (H2′, d, 2H), 7.66 (H7, t,
1H), 7.45 (H6, t, 1H), 6.95 (H3′, d, 2H), 6.78 (NH, d, 1H),
6.72 (H2′′, d, 2H), 3.76 (OCH3, s, 3H), 2.80 (CH3, d, 3H).
13C NMR (DMSO-d6) δ: 162.2 (C=O), 161.9 (C2), 155.5
(C4′), 152.0 (C1′′), 138.3 (C4), 134.2 (C4′′), 133.5 (C10),
131.8 (C1′), 129.7 (C5), 129.7 (C7), 128.5 (C9), 125.9 (C1),
125.9 (C3), 124.9(C6), 122.3 (C3′′), 121.3 (C2′), 120.7 (C8),
114.0 (C3′), 112.2 (C2′′), 55.1 (OCH3), 29.4 (CH3). MS m/z
(CI+): 426.9 ([M + 1]). MS m/z (high-resolution EI) calcd.
for C25H22N4: 426.1692; found: 426.1673. Anal. calcd. for
C25H22N4O3 (MW 426.17): C 70.40, H 5.20, N 13.14;
found: C 69.86, H, 5.30, N 13.10.
R = 2′, 5′-dimethoxy, 5–1G: IR (KBr disk) (cm–1): 3323,
2964, 1657, 1603, 1539, 1449, 1263, 1069, 865, 808, 755,
1
700, 469. H NMR (DMSO-d6) δ: 12.4 (OH, s), 11.4 (amide
NH, s), 8.5 (H4,8, bs), 8.2 (H5, bs), 8.1 (outer amide NH, s),
© 2004 NRC Canada