Synthesis and photochromic properties of 11-phenoxy-2-phenylnaphth[2,3-f]indole-5,10-dione

Article abstract of DOI:10.1016/j.mencom.2008.11.004

11-Phenoxy-2-phenylnaphth[2,3-f]indole-5,10-dione has been synthesized, its photochromic properties have been studied, and photoinduced 10-phenoxy-2-phenylnaphth[2,3-f]indole-5,11-dione has been isolated.

Full text of DOI:10.1016/j.mencom.2008.11.004

Mendeleev
Communications
Mendeleev Commun., 2008, 18, 302–304
Synthesis and photochromic properties of
11-phenoxy-2-phenylnaphth[2,3-f]indole-5,10-dione
Ekaterina A. Kolodina,a Mark S. Shvartsberg*a and Nina P. Gritsana,b
a Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences,
630090 Novosibirsk, Russian Federation. Fax: + 7 383 330 7350; e-mail: shvarts@kinetics.nsc.ru
b Novosibirsk State University, 630090 Novosibirsk, Russian Federation
DOI: 10.1016/j.mencom.2008.11.004
11-Phenoxy-2-phenylnaphth[2,3-f]indole-5,10-dione has been synthesized, its photochromic properties have been studied, and
photoinduced 10-phenoxy-2-phenylnaphth[2,3-f]indole-5,11-dione has been isolated.
Polycyclic para-quinones bearing an aryloxy group at the
O
B
O
OPh
C
OPh O
peri-position to the carbonyl undergo a photochemical arylo-
tropic rearrangement.1–4 It consists in the migration of the aryl
group to the carbonyl oxygen accompanied by the reorganiza-
tion of the π-bond system of the molecule and is usually
photochemically reversible (Scheme 1).
hv1
hv2
A
D
O
1
2
Scheme 2
O
OAr
OAr
O
pyrrole ring, although the loss of reversibility could not be
excluded. This prompted us to synthesize 11-phenoxy-2-phenyl-
naphth[2,3-f]indole-5,10-dione 3 and to study its photochromic
properties.
The synthesis of quinone 3 is presented in Scheme 3. To
form the pyrrole ring, a general approach based on vic-func-
tionalized arylacetylenic precursors has been applied.9,10
hv1
hv2
O
O
Scheme 1
It was shown previously3,5,6 that photoinduced ana-quinones
are highly reactive towards nucleophiles. Reactions of the photo-
induced form with water and other nucleophiles could be the
reason for a fatigue of the photochromic aryloxyquinones.
Photochromic properties of such compounds (quantum yields
of photocoloration and fading, photoequilibrium states, fatigue,
etc.) depend on the chemical structure, including the positions
and character of substituents.2–7 For example, introduction of
amino, alkylamino and dialkylamino substituents into the 2-posi-
tion of 1-aryloxy-9,10-anthraquinones results in the irreversibility
of photorearrangement.7 At the same time, these substituents
reduce significantly the reactivity of the photoinduced forms
(ana-quinones) towards nucleophiles.3,6,7 The most stable of
them, 2-alkylamino-9-aryloxy-1,10-anthraquinones, have been
isolated in a crystalline state and characterized.7 Unlike the
amino and N-alkylated amino derivatives, 2-acylamino- and
2-methoxy-substituted 1-aryloxy-9,10-anthraquinones are typical
photochromic compounds.3
O
Cl
O
Cl
NH2
NH2
I
I2, HIO3
aqueous
dioxane
O
O
4
5
O
O
Cl
Ph
Na2CO3
NH2
KOH, Py
Pd(PPh3)2Cl2
CuI, aqueous
dioxane
Ph
O
6
O
Cl
OPh
PhOH,
KOH
NH
NH
10
5
11
1
Ph
Ph
3
Cu
Annulation of the anthraquinone nucleus at the 2,3-positions
by the benzene ring affords an improvement in the photochromic
characteristics of peri-aryloxyquinones.1,2 6-Phenoxy-5,12-naph-
thacenequinone 1 is characterized by a low fatigue and com-
paratively stable ana-form 2, which has been isolated in a crys-
talline state (Scheme 2).1,2 These features allow us to use
phenoxyquinone 1 in devices for the optical registration and
storage of information and in the light-protective materials.2,4,8
Thus, the introduction of monosubstituted amino groups in
the 2-position of 1-aryloxy-9,10-anthraquinone, as well as its
2,3-annulation by the benzene ring, lead to a considerable
reduction of reactivity of photoinduced form. It is reasonable
to expect the improved photochromic properties of 1-aryloxy-
9,10-anthraquinone fused with aromatic π-electron-excessive
O
O
7
3
Scheme 3
2-Amino-1-chloro-9,10-anthraquinone 4 was iodinated by a
mixture of I2 and HIO3.11 2-Amino-1-chloro-3-iodo-9,10-anthra-
quinone 5, obtained in 75% yield, was introduced into Pd,Cu-
catalyzed cross-coupling with phenylacetylene (the Sonogashira
reaction). A convenient modified procedure was employed.10
The reaction was carried out in aqueous dioxane in the presence
of Pd(PPh3)2Cl2 and CuI with Na2CO3 as a base at 85–87 °C.
Under these conditions, the cross-coupling was completed within
15 min, the yield of 2-amino-1-chloro-3-phenylethynyl-9,10-
– 302 –
© 2008 Mendeleev Communications. All rights reserved.

Mendeleev Commun., 2008, 18, 302–304
The photoinduced product is sufficiently stable. Therefore,
(a)
(b)
we succeeded in its isolation from a mixture with 3 using pre-
parative TLC (Silufol plates, benzene–AcOEt). To our knowledge,
this is one of the few isolations in the crystalline state of photo-
chemically generated ana-quinones.1,3,7 The structure of the
photoinduced form as 10-phenoxy-2-phenylnaphth[2,3-f]indole-
5,11-dione (ana-quinone 8) was entirely confirmed.§ Figure 2
shows the electronic absorption spectra of para-quinone 3 and
ana-quinone 8. The long-wavelength absorption maxima of
these spectra are 461 nm (e = 1.76×104 dm3 mol–1 cm–1) for 8
and 411 nm (e = 9.33×103 dm3 mol–1 cm–1) for 3.
2.0
1.5
1.0
0.5
0.0
2.0
1.5
1.0
0.5
0.0
300 400 500 600
300 400 500 600
l/nm
l/nm
1
As would be expected,7 in the H NMR spectrum of ana-
quinone 8, the signals of the protons H4, H9, H3 shifted upfield
relatively to the chemical shifts of the above protons in the
spectrum of para-quinone 3 (Δd 0.4, »0.3, and 0.25 ppm,
respectively). Vice versa, the signal of the proton at nitrogen
atom H1 is shifted downfield by 0.9 ppm.§ The high-resolution
mass spectrum of 8 also confirms its structure. Thus, the photo-
chromic transformations of para-quinone 3 are really described
by Scheme 4.
Figure 1 (a) The electronic absorption spectrum of 11-phenoxy-2-phenyl-
naphth[2,3-f]indole-5,10-dione 3 in benzene at room temperature (C =
= 1.6×10–4 mol dm–3) and its changes upon irradiation at 436 nm for 10, 30
and 70 s. (b) The electronic absorption spectrum recorded after photolysis
of 3 in benzene at 436 nm for 240 s and its changes upon irradiation at
546 nm for 1, 3, 6, 12 and 18 min.
anthraquinone 6 was 90%. Cyclization of acetylene 6 occurred
in pyridine in the presence of powdered KOH at 115 °C and
afforded 11-chloro-2-phenylnaphth[2,3-f]indole-5,10-dione 7 in
69% yield. Substitution of the chlorine atom by the phenoxy
group in compound 7 proceeded under the action of phenol and
KOH in the presence of a copper powder at 170–175 °C to give
phenoxyquinone 3. The yield of 3 was 65%.†
O
OPh
OPh
O
NH
NH
1
10
hv1
hv2
10
11
11
1
Ph
Ph
3
3
peri-Phenoxy-para-quinone 3, like other analogous quinone
derivatives, rearranges on irradiation with UV and visible light.‡
Figure 1(a) shows typical changes in the electronic absorption
spectrum of a benzene solution of 3 upon irradiation at 436 nm.
In the course of irradiation, the intensity of absorption bands
of 3 (lmax = 311 and 411 nm) decreases and new absorption
bands (lmax = 437 and 461 nm) and a shoulder (at ~520 nm)
appear in the visible region of the spectrum. Irradiation of the
sample for additional 170 s does not result in further spectral
changes.
On the contrary, irradiation of the photolysed sample with
long-wavelength light (546 nm), which is absorbed by the photo-
induced form only, results in the complete recovery of the
initial spectrum of para-quinone 3 [Figure 1(b)]. These spectral
changes are characteristic of reversible photorearrangement of a
para-quinoid structure to ana-quinoid one.1–4,6–8,12,13
O
O
3
8
Scheme 4
Irradiation of a benzene solution of 3 at 436 nm affords a
photostationary state with a 3:8 ratio of 38:62 [Figure 1(b)].¶
The quantum yields of the coloration and fading reactions††
were 0.22 0.02 (436 nm) and 0.015 0.002 (546 nm), respec-
tively. Note that similar quantum yields are known for naph-
40
1
30
20
†
The 1H NMR spectra were recorded using a Bruker DPX 200 spectro-
2
meter in CDCl3 at room temperature. The IR spectra were recorded
using a Bruker Vector 22 spectrometer. The electronic absorption spectra
were recorded on a UV-VIS Shimadzu 2401PC spectrometer. The
high-resolution mass spectra were measured using a Thermo Electron
Corporation DFS spectrometer.
10
0
3: mp 284.5–285.5 °C (toluene). 1H NMR, d: 6.99 (d, 1H, H3, J 2.1 Hz),
7.00–7.10 (m, 3H, PhO), 7.25–7.35 (m, 2H, PhO), 7.35–7.50 (m, 3H,
Ph), 7.60–7.75 (m, 4H, H7(8), Ph), 8.15–8.25 (m, 1H, H9(6)), 8.25–8.35
(m, 1H, H6(9)), 8.62 (s, 1H, H4), 8.80 (br. s, 1H, NH). IR (n/cm–1):
1594, 1667, 1734 (O=C–C=C–C=O), 3454 (NH). UV [benzene, lmax/nm
(e/dm3 mol–1 cm–1)]: 311 (4.11×104), 411 (9.33×103).
300
400
500
600
l/nm
Figure 2 The electronic absorption spectra of (1) 11-phenoxy-2-phenyl-
naphth[2,3-f]indole-5,10-dione 3 and (2) 10-phenoxy-2-phenylnaphth[2,3-f]-
indole-5,11-dione 8 in benzene at room temperature.
1
5: mp 244–245 °C (toluene). H NMR (200 MHz) d: 5.49 (br. s, 2H,
NH2), 7.70–7.80 (m, 2H, H6(7)), 8.15–8.30 (m, 2H, H5(8)), 8.65 (s, 1H, H4).
6: mp 216.5–217.5 °C (dioxane–hexane). 1H NMR, d: 5.65 (br. s, 2H,
NH2), 7.45–7.55 (m, 3H, Ph), 7.60–7.70 (m, 2H, Ph), 7.75–7.85 (m, 2H,
H6(7)), 8.25–8.40 (m, 2H, H5(8)), 8.44 (s, 1H, H4). IR (n/cm–1): 1599, 1677,
1736 (O=C–C=C–C=O), 2210 (CºC), 3403, 3512 (NH2). UV [benzene,
8: mp 222.5–224.5 °C. 1H NMR, d: 6.75 (d, 1H, H3, J 2.0 Hz), 6.95–
§
7.10 (m, 3H, PhO), 7.25–7.50 (m, 5H, Ph, PhO), 7.50–7.70 (m, 4H,
H7(8), Ph), 7.85–8.00 (m, 1H, H9(6)), 8.21 (s, 1H, H4), 8.30–8.40 (m, 1H,
H6(9)), 9.71 (br. s, 1H, NH). UV [benzene, lmax/nm (e/dm3 mol–1 cm–1)]:
307 (2.9×104), 437 (1.6×104), 461 (1.76×104). HRMS: found, 415.1205;
calc. for C28H17NO3, 415.1203.
l
max/nm (e/dm3 mol–1 cm–1)]: 327 (4.3×104), 420 (5.5×103).
7: mp 299.5–300.5 °C (dioxane). 1H NMR, d: 7.07 (d, 1H, H3, J 2.2 Hz),
¶
An aliquot portion of a benzene solution of compound 3 of known
7.40–7.60 (m, 3H, Ph), 7.70–7.85 (m, 4H, H7(8), Ph), 8.25–8.40 (m, 2H,
H6(9)), 8.64 (s, 1H, H4), 9.09 (br. s, 1H, NH). IR (n/cm–1): 1597, 1673, 1734
(O=C–C=C–C=O), 3454 (NH). UV [benzene, lmax/nm (e/dm3 mol–1 cm–1)]:
311 (3.9×104), 406 (9.4×103).
The photolysis of benzene solutions was performed using the selected
436 or 546 nm lines of a high-pressure Hg lamp equipped with a water
filter and a combination of glass filters.
concentration was irradiated to reach a photostationary state. The formed
mixture of quinones 3 and 8 was separated by preparative TLC, 3 was
quantitatively extracted with a benzene–AcOEt mixture and its content
was determined by electronic absorption spectroscopy. The ratio of 3 to 8
in the irradiated solution was calculated. Completeness of the isolation of 3
from the solutions by this procedure was confirmed in special experiments.
The accuracy was 2%.
‡
– 303 –

Mendeleev Commun., 2008, 18, 302–304
3
4
N. P. Gritsan and L. S. Klimenko, J. Photochem. Photobiol. A: Chem.,
1993, 70, 103.
thacenequinone 1 (0.34–0.6 and 0.049 in aromatic hydro-
carbons).12,13
Organicheskie fotokhromy, ed. A. V. Eltsov, Khimia, Leningrad, 1982,
p. 224 (Organic Photochromes, ed. A. V. Eltsov, Consuiltants, Burean,
New York, 1990, p. 210).
N. P. Gritsan, L. S. Klimenko, Z. V. Leonenko, I. Ya. Mainagashev, V. I.
Mamatyuk and V. P. Vetchinov, Tetrahedron, 1995, 51, 3061.
L. S. Klimenko, Z. V. Leonenko and N. P. Gritsan, Mol. Cryst. Liq.
Cryst., 1997, 297, 181.
E. P. Fokin, S. A. Russkikh, L. S. Klimenko and V. V. Russkikh, Izv. Sib.
Otd. Akad. Nauk SSSR, Ser. Khim. Nauk, 1978, no. 7(3), 110 (in Russian).
F. Buchholtz, A. Zelichenok and V. Krongauz, Macromolecules, 1993,
26, 906.
As was mentioned above, the fatigue of the photoinduced
ana-anthraquinones is predominantly determined by their reac-
tivity towards nucleophiles (H2O, ROH, NHR2, etc.).3,6 To compare
the reactivity of synthesized ana-quinone 8 and known ana-naph-
thacenequinone 2, we measured the kinetics of their destruc-
tion in 96% ethanol. The rate constants are (7.6 0.2)×10–5 s–1
(t = 3.7 h) for 8 and (1.1 0.05)×10–4 s–1 (t = 2.5 h) for 2. It
indicates the lesser reactivity of 8 towards the nucleophiles in
comparison with 2. Hence, the replacement of benzene ring D
in phenoxynaphthacenequinone 1 by the pyrrole one slightly
enhances the stability of the photoinduced ana-quinone and
reduces fatigue of new photochromic quinone 3.
In conclusion, 11-phenoxy-2-phenylnaphth[2,3-f]indole-5,10-
dione 3, a heterocyclic analogue of known photochrome 6-phenoxy-
5,12-naphthacenequinone 1, has been synthesized for the first
time. On irradiation, this compound undergoes reversible photo-
isomerization to give a sufficiently stable 10-phenoxy-5,11-quinone
(ana-quinone). The photoinduced ana-quinone was isolated
and characterized. Spectral characteristics of the photochromic
para-quinone and its photoinduced ana-form were determined
and the quantum yields of both photochemical steps were
measured.
5
6
7
8
9
S. Cacchi and G. Fabrizi, Chem. Rev., 2005, 105, 2873.
10 M. S. Shvartsberg, I. I. Barabanov and L. G. Fedenok, Usp. Khim., 2004,
73, 171 (Russ. Chem. Rev., 2004, 73, 161).
11 M. S. Shvartsberg, A. V. Piskunov and A. A. Moroz, Izv. Akad. Nauk
SSSR, Ser. Khim., 1990, 1101 (Bull. Acad. Sci. USSR, Div. Chem. Sci.,
1990, 39, 987).
12 J. Malkin, A. Zelichenok, V. Krongauz, A. S. Dvornikov and P. M.
Rentzepis, J. Am. Chem. Soc., 1994, 116, 1101.
13 Y. Yokoyama, S. Fukui and Y. Yokoyama, Chem. Lett., 1996, 355.
14 N. P. Gritsan and N. M. Bazhin, Izv. Akad. Nauk SSSR, Ser. Khim.,
1980, 1275 (Bull. Acad. Sci. USSR, Div. Chem. Sci., 1980, 29, 897).
15 N. P. Gritsan and N. M. Bazhin, Izv. Akad. Nauk SSSR, Ser. Khim.,
1981, 280 (Bull. Acad. Sci. USSR, Div. Chem. Sci., 1981, 30, 210).
16 N. P. Gritsan, Ph.D. (Phys.-Math.) Thesis, Novosibirsk, 1979, pp. 129–132
(in Russian).
References
1 Yu. E. Gerasimenko and N. T. Poteleschenko, Zh. Org. Khim., 1971, 7,
2413 (in Russian).
2 V. A. Barachevsky, in Organic Photochromic and Thermochromic
Compounds, eds. J. C. Crano and R. Guglielmetti, Plenum Press, New
York, 1999, vol. 1, p. 267.
†† Photolysis quantum yields were measured using the isomerization of
2-dialkylamino-1,4-naphthoquinones14,15 as an actinometric photoreaction
with a quantum yield of 0.1 for the photoisomerization of 2-dimethyl-
amino-3-chloro-1,4-naphthoquinone in benzene.16
Received: 12th May 2008; Com. 08/3136
– 304 –