526
F. Azizian et al. / Dyes and Pigments 92 (2011) 524e530
mixture was poured into cold, dilute HCl (0.01 M, aq, 200 mL) and
extracted with CH2Cl2 (2 ꢁ 100 mL). The combined organic extracts
were washed with dilute NaOH (0.1 M, aq, 50 mL) and water
(2 ꢁ 50 mL), dried over sodium sulphate and evaporated to afford
the crude product which was purified by column chromatography
(30% ethyl acetate in toluene) and recrystallisation (ethyl acetate in
hexane). The following compounds were obtained by this protocol:
d, J ¼ 2.3, 40-H), 7.58 (2H, m, 5-H and 6-H), 7.69 (1H, d, J ¼ 8.9, 60-H),
7.85 (2H, m, Ar-H), 8.12 (1H, m, 4-H), dC 11.49, 13.40, 20.04, 27.93,
37.79, 43.28, 43.41, 59.24, 59.36, 83.27, 83.75, 95.88, 104.93, 107.88,
112.74, 113.74, 117.35, 117.86, 120.56, 122.76, 123.04, 123.80, 126.17,
127.21, 128.33, 130.46, 131.51, 134.22, 146.59, 148.02, 149.81, 154.51,
165.71, 169.29, 170.17, found [M þ H]þ ¼ 585.2384 C37H32N2O5
requires [M þ H]þ ¼ 585.2389.
2.6.1. 30-Anilino-90-diethylaminobenzo[a]fluoran
2.6.5. 90-Diethylamino-30-morpholinobenzo[a]fluoran
7a from 2 and aniline after column chromatography and
recrystallisation as pink microcrystals in 19% yield, m.p.
200e204 ꢀC [16], nmax (cmꢂ1) 3378.4, 1740.3, 1236.1, dH 1.15 (6H, t,
J ¼ 7.2, (CH3CH2)2N), 3.33 (4H, q, J ¼ 7.2, (CH3CH2)2N), 5.90 (1H, s,
NH), 6.35 (1H, dd, J ¼ 8.8 and 2.4, 100-H), 6.43 (1H, d, J ¼ 2.8, 80-H),
6.51 (1H, d, J ¼ 8.8, 110-H), 6.85 (1H, dd, J ¼ 8.8 and 2.4, 20-H), 6.92
(3H, m, Ar-H,10-H), 7.06 (4H, m, Ar-H, 7-H), 7.13 (1H, d, J ¼ 2.4, 40-H),
7.28 (1H, d, J ¼ 9.0, 60-H), 7.55 (2H, m, 5-H and 6-H), 7.65 (1H, d,
J ¼ 9.0, 50-H), 8.11 (1H, m, 4-H), dC 12.52, 44.42, 84.82, 96.90, 106.05,
108.71, 108.75, 113.20, 118.11, 118.76, 120.34, 121.21, 123.56, 124.90,
125.13, 126.15, 126.95, 128.26, 129.29, 131.21, 132.51, 135.14, 138.11,
139.39, 142.58, 149.02, 149.60, 150.85, 155.65, 170.38, found
[M þ H]þ ¼ 513.2169 C34H28N2O3 requires [M þ H]þ ¼ 513.2178.
7e from 2 and morpholine after column chromatography as pale
beige microcrystals in 57% yield, m.p. 140e144 ꢀC, nmax (cmꢂ1
)
1750.0, 1306.9, 1227.0, dH (DMSO-d6) 1.16 (6H, t,
J
¼
7.2,
(CH3CH2)2N), 3.14 (4H, m, eCH2NCH2e), 3.34 (4H, q, J ¼ 7.2,
(CH3CH2)2N), 3.83 (4H, m, eCH2OCH2e), 6.36 (1H, dd, J ¼ 8.8 and
2.4, 100-H), 6.44 (1H, d, J ¼ 2.4, 80-H), 6.54 (1H, d, J ¼ 8.8, 110-H), 6.90
(1H, dd, J ¼ 8.8 and 2.4, 20-H), 6.99 (1H, d, J ¼ 8.8, 10-H), 7.06 (1H, d,
J ¼ 2.4, 40-H), 7.10 (1H, m, 7-H), 7.36 (1H, d, J ¼ 9.0, 60-H), 7.57 (2H,
m, 5-H and 6-H), 7.78 (1H, d, J ¼ 9.0, 50-H), 8.12 (1H, m, 4-H), dC
(DMSO-d6) 12.94, 21.88, 29.45, 44.85, 49.65, 67.23, 85.17, 94.13,
97.33, 106.49, 109.15, 112.04, 119.58, 124.01, 125.14, 125.70, 126.14,
127.47, 128.66, 129.61, 131.85, 132.85, 135.51, 138.29, 147.72, 149.42,
150.05, 151.35, 156.05, 170.72, found [M þ H]þ ¼ 507.2265
C
32H30N2O4 requires [M þ H]þ ¼ 507.2278.
2.6.2. 90-Diethylamino-30-(4-methoxyanilino)benzo[a]fluoran
7b from 2 and p-anisidine after column chromatography as pale
2.6.6. 60-Di-n-butylamino-20-(4-methoxyanilino)-30-methylfluoran
7g from 6 and p-anisidine after column chromatography as very
pale redepurple microcrystals in 68% yield, m.p. 142e145 ꢀC, nmax
(cmꢂ1) 3394.1, 1746.8, 1240.4, dH 0.95 (6H, t, J ¼ 7.2, (CH3CH2
CH2CH2)2N), 1.33 (4H, sextet, J ¼ 7.2, (CH3CH2CH2CH2)2N), 1.56 (4H,
quintet, J ¼ 7.2, (CH3CH2CH2CH2)2N), 2.40 (3H, s, CH3), 3.26 (4H, t,
J ¼ 7.6, (CH3CH2CH2CH2)2N), 3.42 (1H, bs, NH), 3.74 (3H, s, OCH3),
6.32 (1H, dd, J ¼ 8.8 and 2.4, 70-H), 6.38 (1H, d, J ¼ 2.4, 50-H), 6.52
(1H, d, J ¼ 8.8, 80-H), 6.65 (2H, m, Ar-H), 6.74 (2H, m, Ar-H), 6.88 (1H,
s, 10-H), 7.16 (1H, s, 40-H), 7.18 (1H, dd, J ¼ 7.2 and 1.2, 7-H), 7.65 (2H,
m, 5-H and 6-H), 8.02 (1H, dd, J ¼ 7.2 and 1.2, 4-H), dC 13.98, 20.28,
23.00, 29.26, 50.79, 55.72, 83.39, 97.51, 104.46, 108.57, 114.78,
116.42, 118.09, 118.86, 118.90, 124.00, 125.04, 126.99, 128.74, 129.72,
131.12, 134.98, 139.90, 140.47, 150.81, 152.57, 152.71, 152.78, 157.96,
pink microcrystals in 58% yield, m.p. 150e154 ꢀC, nmax (cmꢂ1
)
3374.7, 1736.9, 1237.0, dH 1.15 (6H, t, J ¼ 7.2, (CH3CH2)2N), 3.33 (4H,
q, J ¼ 7.2, (CH3CH2)2N), 3.84 (3H, s, OCH3), 5.51 (1H, s, NH), 6.35 (1H,
dd, J ¼ 8.8 and 2.4, 100-H), 6.43 (1H, d, J ¼ 2.8, 80-H), 6.51 (1H, d,
J ¼ 8.8,110-H), 6.75 (1H, dd, J ¼ 9.2 and 2.4, 20-H), 6.85 (2H, m, Ar-H),
6.92 (1H, d, J ¼ 9.2, 10-H), 7.05 (2H, m, Ar-H), 7.13 (1H, m, 7-H), 7.16
(1H, d, J ¼ 2.4, 40-H), 7.32 (1H, d, J ¼ 9.2, 60-H), 7.55 (2H, m, 5-H and
6-H), 7.65 (1H, d, J ¼ 9.2, 50-H), 8.11 (1H, m, 4-H), dC 12.52, 21.07,
44.42, 60.42, 84.82, 96.90, 106.06, 108.74, 113.22, 118.09, 118.72,
120.37, 121.24, 123.58, 124.87, 125.09, 126.18, 126.99, 128.23, 129.31,
131.19, 132.52, 135.16, 138.08, 139.41, 142.60, 148.99, 149.59, 150.90,
155.60, 170.35, found [M þ H]þ ¼ 543.2274 C35H30N2O4 requires
[M þ H]þ ¼ 543.2278.
169.44 found [M
þ
H]þ
¼
563.2906 C36H38N2O4 requires
2.6.3. 90-Diethylamino-30-(4-trifluoromethylanilino)benzo[a]
fluoran
[M þ H]þ ¼ 563.2910.
7c from 2 and 4-trifluoromethylaniline after column chroma-
tography as pale yellow microcrystals in 86% yield, m.p.137e140 ꢀC,
nmax (cmꢂ1) 3368.2, 1740.0, 1235.3, 1096.8, dH 1.16 (6H, t, J ¼ 7.2,
(CH3CH2)2N), 3.35 (4H, q, J ¼ 7.2, (CH3CH2)2N), 5.95 (1H, s, NH), 6.38
(1H, dd, J ¼ 8.8 and 2.4, 100-H), 6.43 (1H, d, J ¼ 2.8, 80-H), 6.51 (1H, d,
J ¼ 8.8, 110-H), 6.92 (1H, dd, J ¼ 8.8 and 2.4, 20-H), 7.02 (3H, m, Ar-H,
10-H), 7.13 (1H, m, 7-H), 7.41 (1H, d, J ¼ 9.0, 60-H), 7.47 (3H, m, Ar-H,
40-H), 7.58 (2H, m, 5-H and 6-H), 7.75 (1H, d, J ¼ 9.0, 50-H), 8.10 (1H,
d, J ¼ 7.2, 4-H), dC 12.51, 78.12, 44.44, 84.78, 96.90, 105.93, 108.86,
114.22, 115.55, 116.25, 119.00, 121.44, 121.80, 123.58, 124.99, 125.30,
125.92,126.56,126.93,127.23,128.23,129.04,129.36,131.38,132.25,
135.24, 137.41, 146.33, 149.08, 150.83, 155.51, 170.33, found
[M þ H]þ ¼ 581.2030 C35H27N2O3F3 requires [M þ H]þ ¼ 581.2047.
3. Discussion
In order to assess the versatility of the palladium-catalysed
coupling reaction three bromo-substituted fluorans were examined
as substrates, 30-bromo-90-diethylaminobenzo[a]fluoran 2, 20-
bromo-60-diethylaminofluoran 4 and a commercial sample of 20-
bromo-60-di(n-butylamino)-30-methylfluoran
6 [17]. Fluorans 2
and 4 were derived from the common ketoacid 1 which was
readily available from the FriedeleCrafts reaction between 3-
diethylaminophenol and phthalic anhydride in toluene [18]. Heat-
ing 1 with either 6-bromo-2-naphthol or 4-bromoanisole in 85%
sulphuric acid gave, after basification and purification, the requisite
bromofluorans 2 and 4 in moderate yield (Scheme 3). As a conse-
quence of reported instances where debromination had occurred
during the attempted preparation of bromofluorans via this general
method [19] careful structural characterisation of 2 and 4 was
undertaken.
2.6.4. 90-Diethylamino-30-(4-ethoxycarbonylanilino)benzo[a]
fluoran
7d from 2 and ethyl 4-aminobenzoate after column chroma-
tography and recrystallisation as fawn microcrystals in 53% yield,
m.p. 99e102 ꢀC, nmax (cmꢂ1) 3349.7, 1737.6, 1686.0, 1595.2, 1280.3,
1172.8, dH 1.15 (6H, t, J ¼ 7.2, (CH3CH2)2N), 1.36 (3H, t, J ¼ 7.2,
OCH2CH3), 3.34 (4H, q, J ¼ 7.2, (CH3CH2)2N), 4.32 (2H, q, J ¼ 7.2,
OCH2CH3), 6.37 (1H, dd, J ¼ 8.8 and 2.4, 100-H), 6.41 (1H, d, J ¼ 2.4,
80-H), 6.45 (1H, bs, NH), 6.52 (1H, d, J ¼ 8.8, 110-H), 6.95 (4H, m, Ar-
H, 10-H, 20-H), 7.10 (1H, m, 7-H), 7.36 (1H, d, J ¼ 8.9, 60-H), 7.45 (1H,
The key 1H NMR signals employed for the characterisation of 2
were the ortho-coupled doublet at
d
7.45 (J ¼ 9.2 Hz, 10-H), a double
doublet at
doublet at
d
7.21 (J ¼ 9.2 and 2.4 Hz, 20-H) and the meta-coupled
d
7.92 (J ¼ 2.4 Hz, 40-H) which confirmed the position of
the bromine atom. A group of mutually coupled signals resonating
upfield of these signals assigned tothe bromonaphthalene unit were
assigned to 110-H (
d
6.50, d, J ¼ 8.8 Hz), 100-H (
6.37, dd, J ¼ 8.8 and
d