Arkivoc 2019, vi, 0-0
Djeukoua, D. K. S. et al.
3545 (O-H), 3134 (N-H), 1726 (C=O), 1598 (C=C), 1290 (C-O) 1213 (C-N) 1490 (N=N) cm-1. 1H NMR (DMSO-d6,
400 MHz): δH 8.82 (2H, dd, JHH 8.1 and 1.2 Hz, H-9’, H-9’’), 7.74 (2H, s, H-1’, H-1’’), 7.71 (2H, ddd, JHH 7.5 JHH 7.2
and 1.6 Hz, H-7’, H-7’’), 7.53 (1H, d, JHH 7.2 Hz, H-6), 7.45 (2H, ddd, JHH 7.4 JHH 6.6 and 1.5 Hz, H-8’, H-8’’), 7.39
(2H, dd, JHH 8.9 and 1.4 Hz, H-6’, H-6’’), 7.37 (1H, d, JHH 7.3 Hz, H-5), 2.80 (3H, s, CH3). 13C NMR (DMSO-d6, 100
MHz): δC 162.9 (CH3C=O), 162.9 (C-4’, C-4’’); 157.0 (C-4), 155.4 (C-3’, C-3’’), 154.5 (C-1), 153.3 (C-9b’, C-9b’’),
155.1 (C-5a’, C-5a’’), 148,6 (C-3a’, C-3a’’), 135.4 (C-7’, C-7’’), 135.6 (C-6), 129.9 (C-9’, C-9’’), 126.1 (C-8’, C-8’’),
125.6 (C-1’’, C-1’), 118.2 (C-9a’, C-9a’’), 117.7 (C-6’, C-6’’), 117.4 (C-3), 113.5 (C-2), 102,3 (C-5), 18.4 (C(O)CH3).
ESIMS m/z (%) 607 (1), 552 (1), 521 (2), 517 (5), 493 (3), 413 (1), 384 (2), 360 (9), 284 (3), 270 (100), 228 (3),
208 (29), 189 (2). Anal. Calcd. for C30H17N5O6S2: C, 59.30; H, 2.82; N, 11.53; S, 10.55. Found: C, 59.18; H, 2.79;
N, 11.52; S, 10.52.
2-[2-(2-Acetyloxy)-3-carboxy-5-{2-carboxy-4-(2-hydroxphenyl)-2-thienyl]}phenyl)diazenyl]-4-(2-
hydroxyphenyl)-3-thiophenecarboxylic acid (5c). Compound 5c was obtained as black powder (1.79 g, 58%).
mp > 250 °C. Rf 0.55 in CH2Cl2/AcOEt 80% v/v; UV (EtOH) λmax(Log ε) 235 (1.41), 305 (1.39), 330 (1.42) nm. IR
(solid, KBr, νmax, cm-1): 3621-3500 (free O-H), 3500-3277 (ass O-H), 2291 (=C-H), 1706 (C=O), 1603-1590
(CAr=CAr), 1540-1523 (thiophenic C=C), 1490 (-N=N-), 1371-1234 (C-O), 1194-1110 (C-N), 752 (=CAr-H) cm−1. 1H
NMR (DMSO-d6, 400 MHz): δH 8.73 (1H, d, JHH 1.3 Hz, H-4’’), 8.01 (2H, ddd, JHH 1.7 JHH 6.9 and 8.6 Hz, H-4’, H-
4’’’’), 7.99 (1H, d, JHH 1.3 Hz, H-6’’), 7.83 (2H, dd, JHH 1.1 and 7.8 Hz, H-6’, H-6’’’’), 7.80 (2H, dd, JHH 7.8 and 8.5
Hz, H-5’, H-5’’’’), 7.73 (2H, dd, JHH 1.3 and 6.9 Hz, H-3’, H-3’’’’), 7.56 (2H, s, H-5, H-5’’’), 2.74 (3H, s, C(O)CH3). 13C
NMR (DMSO-d6, 100 MHz): δC 184.0 (3 COOH), 164.5 (COCH3), 154.9 (C-2’, C-2’’’’), 154.8 (C-2’’), 153.7 (C-2, C-
2’’’), 153.4 (C-1’’), 153.3 (C-1’, C-1’’’’) 147,7 (C-4, C-4’’’), 135.4 (C-3, C-3’’’), 135.1 (C-5’’), 128.8 (C-4’, C-4’’’’),
127.0 (C-4’’), 125.3 (C-3’’), 125.2 (C-5, C-5’’’), 120.0 (C-6’, C-6’’’’), 118.2 (C-6’’), 117.1 (C-5’, C-5’’’’); 114.8 (C-3’,
C-3’’’’), 18.1; (CH3). ESIMS m/z (%) 675 (1), 628 (3), 535 (3), 517 (3), 493 (3), 413 (1), 390 (6), 338 (6), 284 (5),
270 (100), 248 (16), 208 (7), 186 (15). Anal. Calcd. for C31H20N4O10S2: C, 55.35; H, 3.00; N, 8.33; S, 9.53; S,
14.05. Found: C, 55.38; H, 2.98; N, 8.30; S, 13.98.
2-(Acetyloxy)-3-[2-(4imino-4H-thieno[4,3-c]chromen-3-yl)diazenyl]benzoic acid (6). Compound 6 was
obtained as brown powder (1.35 g, 41%). mp 224-226 °C. Rf 0.55 in CH2Cl2/AcOEt 80%); UV (EtOH) λmax(Log ε)
235 (1.28), 275 (1.05), 335 (0.81), 360 (0.81), 420 (0.99) nm. IR (solid, KBr, νmax, cm-1): 3562 (O-H), 3324-3200
(N-H), 2640-2747 (=C-H)1733 (C=O), 1713 (C=N), 1605-1598 (C=C), 1547-1500 (thiophenic C=C), 1490 (-N=N-),
1273-1290 (N-H), 1060-1200 (C=O), 764 (=CAr-H) cm−1. 1H NMR (DMSO-d6, 400 MHz): δH 9.51 (2H; s; =NH); 8.82
(1H, dd, JHH 7.9 and 1.3 Hz, H-9’), 7.88 (1H, dd, JHH 7.9 and 1.3 Hz, H-6), 7,73 ( 1H, ddd, JHH 7.3 JHH 6.5 and 1.5
Hz, H-7’), 7.49 (1H, dd, JHH 7.0 and 1.1 Hz, H-6’), 7.40 (1H; s, H-1’), 7.39 (ddd, JHH 7.2 JHH 6.7 and 1.6 Hz, H-8’),
6.96 (1H, dd, JHH 7.9 and 8.3 Hz, H-5), 6.89 (1H, dd, JHH 8.3 and 0.9 Hz, 1H, H-4), 2.74 (3H, s, CH3). 13C NMR
(DMSO-d6, 100 MHz): δC 183.8 (COOH), 161.8 (COCH3), 157.3 (C-4’), 155.5 (C-5a’), 155.1 (C-9b’), 154.4 (C-3’),
154.2 (C-3a’), 148.9 (C-2), 135.8 (C-1), 135.6 (C-7’), 130.7 (C-6), 129.9 (C-9’), 125.4 (C-8’), 119.7 (C-1’), 119.2 (C-
4), 117.4 (C-6’), 117.3 (C-5), 115.8 (C-9a’), 112.4 (C-3), 18.2 (C(O)CH3). ms: (ESI+) m/z (%) 384 (17), 360 (100),
338 (21), 301 (8), 284 (14), 270 (68). Anal. Calcd. for C20H13N3O5S: C, 58.96; H, 3.22; N, 10.31; S, 7.87. Found: C,
58.98; H, 3.25; N, 10.28; S, 7.85.
Cyclic voltammetry. A PalmSens type 3 potenstiostat running with PSTrace 4.4 software, supplied by PalmSens
BV, Houten (The Netherlands) was used for the cyclic voltammetric (CV) measurements. A standard single
compartment three electrode cell was used with an Ag pseudo-reference electrode and a stainless steel rod
counter electrode. The working electrode was a glassy carbon electrode (GCE). All electrochemical
experiments were carried out without degassing the supporting electrolyte solution.
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