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References
14. Grehn, L.; Gunnarsson, K.; Ragnarsson, U. Acta Chem.
Scand., Ser. B 1987, B41, 18.
1. Moura, J. C. V. P. In Colorants for Non-Textile Applica-
tions; Freeman, H. S.; Peters, A. T., Eds.; Elsevier Sci-
ence: New York, 2000; p. 189.
2. Kapuscinski, J. J. Histochem. Cytochem. 1990, 38, 1323.
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37, 1699.
4. Imai, T. Med. Technol. (Tokyo) 1985, 13, 1403.
5. Schmidt, R. Ger. Offen. DE 4 117 619, 1992.
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DE 3 813 503, 1989.
15. Grehn, L.; Maia, H. L. S.; Monteiro, L. S.; Montenegro,
M. I.; Ragnarsson, U. J. Chem. Res. 1991, (S), 144; (M),
1501.
16. To a solution of 3c in dry acetonitrile (47 mmol dm−3) 0.3
equiv. of DMAP were added under rapid stirring at room
temperature, followed by 3.6 equiv. of tert-butyl pyrocar-
bonate. The reaction was stirred overnight and monitored
by TLC (diethyl ether-n-hexane, 9:1). Evaporation under
reduced pressure gave a residue that was purified by dry
chromatography on silica (diethyl ether–light petroleum,
9:1) and crystallisation from ethyl acetate-n-hexane to
give 4c as an orange solid in a 99% yield. Mp 101.8–
103.4°C. Rf 0.74 (diethyl ether-n-hexane, 8:2). UV–vis
(MeOH): umax 450 (17282) nm. FTIR (neat): wmax 2976,
2929, 2856, 1747, 1732, 1681, 1602, 1562, 1520, 1446,
1398, 1367, 1311, 1255, 1197, 1148, 1066, 1039, 946, 902,
7. Behrendt, R.; Schenk, M.; Musiol, H.; Moroder, L. J.
Peptide Sci. 1999, 5, 519.
8. Sebestye´n, F.; Szendrei, G.; Ma´k, M.; Do´da, M.; Illye´s,
E.; Szo´ka´n, G.; Kindla, K.; Rapp, W.; Szego´, P.;
`
Caˆmpian, E.; Furka, A. J. Peptide Sci. 1998, 4, 294.
9. Gonc¸alves, M. S. T.; Oliveira-Campos, A. M. F.; Moura,
J. C. V. P.; Maia, H. L. S.; Gomes, J. I. N. R.; Hrdina,
R. Dyes and Pigments 1998, 36, 373 and references cited
therein.
1
848, 823, 750 cm−1. H NMR (CDCl3, 300 MHz): l 1.16
(9H, s, C(CH3)3), 1.68 (3H, d, J 7.0 Hz, a-CH3), 3.12
(6H, s, N(CH3)2), 3.80 (3H, s, OCH3), 5.18 and 5.21 (1H,
2×d, J 7.0 Hz, a-H), 6.77 (2H, d, J 9.3 Hz, 2×ortho-ArH
N(CH3)2), 7.53 (1H, t, J 7.8 Hz, 5-H), 7.63 (1H, dt, J 7.0
Hz, 1.2 Hz, 4- or 6-H), 7.90 (2H, d, J 9.3 Hz, 2×meta-
ArH N(CH3)2), 7.99 (1H, dt, J 7.8 Hz, 1.2 Hz, 6- or 4-H),
8.06 (1H, t, J 1.8 Hz, 2-H). 13C NMR (CDCl3, 75.4
MHz): l 15.2 (a-CH3), 27.3 (C(CH3)3), 40.2 ((CH3)2),
52.4 (a-C), 53.5 (O-CH3), 83.8 (C(CH3)3), 111.4 (2%-C,
6%-C), 120.9 (2-C), 125.1 (3%-C, 5%-C), 125.4 (4-C), 128.1
(5-C), 128.8 (6-C), 138.1 (1-C), 143.3 (4%-C), 152.4 (3-C),
152.6 (1%-C, OꢀC-OC(CH3)3), 171.4 (OꢀC-N), 172.3
(OꢀC-OCH3). The assignments were supported by the
Dept 135 technique. Anal. calcd for C24H30N4O5: C,
63.42; H, 6.65; N, 12.33. Found: C, 63.52; H, 6.55; N,
12.21. Compound 4c was treated with DEAEA according
to the procedure described in Ref. 14 above to give 5c in
a 63% yield, which compared well with a genuine sample
prepared by a different procedure.
10. Nyasse, B.; Grehn, L.; Maia, H. L. S.; Monteiro, L. S.;
Ragnarsson, U. J. Org. Chem. 1999, 64, 7135.
11. Bodanszky, M.; Bodanszky, A. The Practice of Peptide
Synthesis; Springer-Verlag: Berlin, 1984; p. 145.
12. Gomes, J. I. N. R.; Griffiths, J.; Maia, H. L. S.; Moura,
J. C. V. P.; Oliveira-Campos, A. M. F. Dyes and Pig-
ments 1991, 17, 269.
13. Typical experiment: 3-[(N,N-dimethylaminophenyl)-4%-
diazenyl]-benzoic acid (1) was reacted in a 1.12-mmolar
scale with alanine methyl ester hydrochloride (2c) in
DMF by a standard DCC/HOBt coupling. After dry
chromatography on silica gel (diethyl ether/n-hexane 9:1)
and recrystallisation from ethyl acetate-n-hexane, 3c was
obtained as an orange solid in a 91% yield. Mp 132.4–
134.1°C. Rf 0.56 (diethyl ether-n-hexane, 9:1). UV–vis
(MeOH): umax 415 (28453) nm. FTIR (KBr, 1%): wmax
3282, 2921, 1752, 1637, 1605, 1538, 1442, 1398, 1372,
1344, 1202, 1150, 1109, 1066 cm−1. 1H NMR (CDCl3, 300
MHz): l 1.57 (3H, d, J 7.5 Hz, a-CH3), 3.12 (6H, s,
N(CH3)2), 3.82 (3H, s, OCH3), 4.80–4.85 (1H, m, a-H),
6.79 (2H, d, J 9.3 Hz, 2×ortho-ArH N(CH3)2), 6.85 (1H,
d, J 7.2 Hz, NH), 7.57 (1H, t, J 7.8 Hz, 5-H), 7.86–7.94
(3H, m, 2×meta-ArH N(CH3)2, 4 or 6-H), 8.0 (1H, dt, J
17. N-(3-Aminobenzoyl)-Phe(N-Boc)-OEt was obtained as
an oil in a 32% yield. FTIR (neat): wmax 3378, 2984, 2979,
1732, 1682, 1602, 1497, 1447, 1368, 1258, 1149, 1030, 886,
1
842, 727, 698 cm−1. H NMR (CDCl3, 300 MHz): l 1.04
(9H, s, C(CH3)3), 1.30 (3H, t, J 7.0 Hz, OCH2CH3),
3.40–3.60 (2H, m, CH2C6H5), 4,20–4.35 (2H, m,
OCH2CH3), 5.42, 5.45 (1H, 2×d, J 6.9 Hz, a-H), 7.15
(1H, d, J 7.6 Hz, 4-H), 7.20–7.30 (6H, m, 5-H, C6H5),
7.40 (1H, d, J 7.6 Hz, 6-H), 7.45 (1H, s, 2-H). 13C NMR
(CDCl3; 75.4 MHz): l 14.2 (OCH2CH3), 27.2 C(CH3)3),
35.4 (CH2-C6H5), 58.7 (a-C), 61.6 (OCH2CH3), 83.3
(C(CH3)3), 123.8 (2-C), 126.6 (6-C), 127.4 (4-C), 127.8
(4%-C), 128.5 (3%-C, 5%-C), 129.5 (2%-C, 6%-C), 130.9 (5-C),
137.5 (1%-C, 1-C), 152.7 (3-C, OꢀC-O-C(CH3)3), 170.2
(OꢀC-N) 173.0 (OꢀC-O-CH2CH3).
8.7 Hz, 1.2 Hz, 6- or 4-H), 8.22 (1H,t, J 1.8 Hz, 2-H). 13
C
NMR (CDCl3, 75.4 MHz): l 18.5 (a-CH3), 40.2 (N-CH3),
48.5 (a-C), 52.4 (O-CH3), 111.4 (2%-C, 6%-C), 120.2 (2-C),
125.1 (3%-C, 5%-C), 125.3 (4-C), 128.0 (5-C), 129.2 (6-C),
134.7 (1-C), 143.3 (4%-C), 152.6 (3-C), 153.1 (1%-C), 166.4
(OꢀC-N), 173.5 (O-CꢀO). The assignments were sup-
ported by the Dept 45 technique. Anal. calcd for
C19H22N4O3: C, 64.39; H, 6.26; N, 15.81. Found: C,
64.65; H, 6.21; N, 15.68.