J. Zhang et al. / Tetrahedron Letters 42 (2001) 3599–3601
3601
Scheme 3. Reagents and conditions: (a) BOP, DIEA, CH3CN, 50°C, 84%; (b) HCl, EtOAc, 0°C, 100%; (c) 11, BOP, DIEA,
CH3CN, 50°C, 75% (d) 10, BOP, DIEA, CH3CN, 50°C, 85%.
References
ml), under nitrogen, at room temperature, was added
successively 0.5 g (1.6 mmol) of amine 3, 1.23 g (1.92
mmol) of acid 10, 0.85 g (1.92 mmol) of BOP and 0.833
ml (4.8 mmol) of diisopropylethylamine, and the mixture
was heated at 50°C for 12 h. At the end of the reaction,
a red suspension was obtained, which was further heated
at 80°C in order to obtain an homogeneous solution.
After cooling to room temperature, a red solid was
obtained, which was filtered, washed with Et2O, and
dried under vacuum to afford 1.28 g of 12 (84%). Data of
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1
12: Rf=0.55 (eluent: CH2Cl2/MeOH, 9/1, v/v); H NMR
(300 MHz, CDCl3): l 1.27 (t, J=7 Hz, 3H), 1.43 (s,
27H), 1.97 (m, 6H), 3.38 (m, 6H), 3.56 (q, J=7 Hz, 2H),
3.71 (br s, 4H), 4.05 (m, 6H), 5.04 (br s, 2H), 5.31 (br s,
1H), 6.71 (br s, 1H), 7.00 (s, 2H), 6.88 (app.d, J=9 Hz,
2H), 7.91 (app.d, J=9 Hz, 2H), 7.93 (app.d, J=9 Hz,
2H), 8.32 (app.d, J=9 Hz, 2H); MS (ESI): [M+H]+=
937+, [M+Na]+=959+; IR (CHCl3): 3453, 1706, 1659,
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M.; Spencer, N.; Stoddart, J. F.; Toung, M. J. Org.
Chem. 1998, 63, 3429.
1601, 1588, 1559, 1516, 1493 cm−1
.
11. Data of 1a: Rf=0.50 (eluent: CH2Cl2/MeOH, 9/1, v/v);
1H NMR (300 MHz, CDCl3): l 1.22 (t, J=7 Hz, 3H),
1.42 (s, 54H), 1.70–1.0 (m, 18H), 3.14–3.25 (m, 18H), 3.53
(m, 2H), 3.64 (br s, 4H), 3.77–3.94 (m, 18H), 4.91–5.09
(br s, 10H), 6.49 (br s, 3H), 6.89 (br s, 6H), 7.04 (s, 2H),
6.87 (app.d, J=9 Hz, 2H), 7.87 (app.d, J=9 Hz, 2H),
7.89 (app.d, J=9 Hz, 2H), 8.29 (app.d, J=9 Hz, 2H);
MS (LSIMS): [M+H]+=1988.4+; IR (CHCl3): 3448, 1708,
1653, 1595, 1515 cm−1. Data of 1b: Rf=0.58 (eluent:
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1
CH2Cl2/MeOH, 8/2, v/v); H NMR (300 MHz, CDCl3):
l 1.26 (t, J=7 Hz, 3H), 1.42 (s, 81H), 1.75–2.10 (m,
24H), 3.56 (m, 2H), 3.10–3.80 (m, 28H), 4.05 (m, 24H),
5.20–5.40 (br s, 10H), 6.88 (app.d, J=9 Hz, 2H), 7.87
(app.d, J=9 Hz, 4H), 7.08(s, 2H), 7.06 (s, 4H), 6.97 (s,
2H), 8.29 (app.d, J=9 Hz, 2H); MS (LSIMS): [M+H]+=
2508.9+, [M+K]+=2547.9+; IR (CHCl3): 3452, 1701,
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10. General coupling procedure—an example of the prepara-
tion of G0 dendrimer 12: To a solution of CH3CN (80
1653, 1600, 1587, 1514, 1498 cm−1
.
.
.