Spiropyrans and spirooxazines. 3. Synthesis of photochromic 5′-(4,5-diphenyl-1,3-oxazol-2-yl)-spiro[indoline-2,3′-naphtho[2,3-b] pyran]

Article abstract of DOI:10.1007/s11172-005-0308-2

The reaction of 2-hydroxy-3-(4,5-diphenyl-1,3-oxazol-2-yl)-1-naphthaldehyde with 1,2,3,3-tetramethyl-3H-indolium perchlorate afforded photochromic spiro[indoline-2,3′-naphthopyran] containing a 4,5-diphenyloxazole group in position 5′ of the naphthopyran

Full text of DOI:10.1007/s11172-005-0308-2

Russian Chemical Bulletin, International Edition, Vol. 54, No. 3, pp. 705—710, March, 2005
705
Spiropyrans and spirooxazines
3.* Synthesis of photochromic 5´ꢀ(4,5ꢀdiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)ꢀ
spiro[indolineꢀ2,3´ꢀnaphtho[2,3ꢀb]pyran]
ꢀ
N. A. Voloshin, A. V. Chernyshev, A. V. Metelitsa, I. M. Raskita,
E. N. Voloshina, and V. I. Minkin
Institute of Physical and Organic Chemistry,
Rostov State University,
194/2 prosp. Stachki, 344090 RostovꢀonꢀDon, Russian Federation.
Fax: +7 (863 2) 43 4667. Eꢀmail: photo@ipoc.rsu.ru
The reaction of 2ꢀhydroxyꢀ3ꢀ(4,5ꢀdiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)ꢀ1ꢀnaphthaldehyde with
1,2,3,3ꢀtetramethylꢀ3Hꢀindolium perchlorate afforded photochromic spiro[indolineꢀ2,3´ꢀ
naphthopyran] containing a 4,5ꢀdiphenyloxazole group in position 5´ of the naphthoꢀ
pyran fragment. The merocyanine form of the spiropyran gave complexes with bivalent heavy
cations.
Key words: spiropyrans, photochromism, metal complexes.
Scheme 1
Photochromic organic molecules (including spiroꢀ
pyrans and spirooxazines) have been under intense study
in the last few years because they can be used in optical
systems for recording and displaying information, as well
as in sensors, optobioꢀ and optoelectronics, transport sysꢀ
tems, and catalysis.2—5
Photochromic transformations of spironaphthopyrans
(Scheme 1) and spirooxazines involve thermally and phoꢀ
tochemically reversible cleavage of the Cspiro—O bond of
the cyclic isomer A followed by cisꢀtransꢀisomerization
into metastable merocyanine form B. The latter spontaꢀ
neously or when exposed to visible light changes to the
starting spiro form.2,3
In recent years, isomerization of spiropyrans and
spirooxazines in the presence of certain chemical species
(specific substrates such as, e.g., metal cations6) has atꢀ
tracted great interest. In this case, spiropyran and spiroꢀ
oxazine molecules usually contain an ionophore fragment
in the orthoꢀposition relative to the pyran/oxazine O atom,
while the phenoxide O atom of the colored isomer proꢀ
vides additionally coordination to the metal cation. Much
research is devoted to spirocyclic photochromes containꢀ
ing ionophore crownꢀether fragments,7—9 the isomerizaꢀ
tion of which is substantially affected by alkali and alkaꢀ
lineꢀearth metal cations. The number of spiro compounds
the transformations of which are affected by transition
and rareꢀearth ions is much smaller. Among them are
spirobenzopyranindolines with methoxy,10—12 piperidinoꢀ
methyl,13 and other electronꢀdonating substituents14 in
position 8 and quinolinespiropyranindolines.15—19 Reꢀ
cently, 5´ꢀbenzothiazolylspirooxazines have been syntheꢀ
sized and found promising for use as photochromic chelatꢀ
ing reagents.20
Oxazole derivatives, especially those containing aroꢀ
matic or heterocyclic substituents in positions 2 and 5, are
good fluorophore systems.21 They are widely used as fluoꢀ
rescent bleaching agents and can form complexes with
transition element ions.22
The present work was devoted to the synthesis and
study of the coordinative power of 5´ꢀ(diphenyloxazoꢀ
lyl)spironaphthopyran (11).
* For Part 2, see Ref. 1.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 693—697, March, 2005.
1066ꢀ5285/05/5403ꢀ0705 © 2005 Springer Science+Business Media, Inc.

706
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 3, March, 2005
Voloshin et al.
Results and Discussion
2ꢀmethoxynaphthaldehyde (7). Demethylation of aldeꢀ
hyde 7 with AlCl3 led to 2ꢀhydroxy derivative 8. The
synthesis of compound 4 involved alkylation of methyl
4ꢀformylꢀ3ꢀhydroxyꢀ2ꢀnaphthoate (1) with iodomethane
under the conditions of solid—liquid PTC in the presence
of 18ꢀcrownꢀ6, hydrolysis of the corresponding methoxyꢀ
naphthoate 2 into naphthoic acid 3, and the reaction of
the latter with NaOMe.
Spiro compound 11 was obtained in two steps as shown
in Scheme 2 by the reaction of tetramethylꢀ3Hꢀindolium
perchlorate (9) with 3ꢀ(4,5ꢀdiphenyloxazolyl)ꢀ2ꢀhydroxyꢀ
naphthaldehyde (8) in AcOH followed by treatment of
2ꢀhydroxynaphthylvinylindolium perchlorate (10) with
ammonia.
The starting material for the synthesis of 2ꢀhydroxyꢀ
naphthaldehyde 8 was sodium 4ꢀformylꢀ3ꢀmethoxyꢀ2ꢀ
naphthoate (4). Its alkylation with 2ꢀchloroꢀ1,2ꢀdiphenylꢀ
ethanone (5) under the conditions of phaseꢀtransfer caꢀ
talysis yielded desyl ester (6). The latter was refluxed
with ammonium acetate in acetic acid according to the
Davidson method23 to give 3ꢀ(4,5ꢀdiphenyloxazolꢀ2ꢀyl)ꢀ
Compounds 2, 3, 6—8, and 11 were identified by
1H NMR spectroscopy; their structures were confirmed
by elemental analysis data.
Spectroscopic and photochemical properties. The specꢀ
troscopic and photochemical properties of spironaphthoꢀ
pyrans were examined in toluene, acetone, acetoniꢀ
trile, and ethanol. Unsubstituted spironaphthopyran
Scheme 2
i. Phaseꢀtransfer catalysis in the presence of 18ꢀcrownꢀ6.

Spiropyrans and spirooxazines
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 3, March, 2005
707
Scheme 3
R =
(11), H (12)
A
I (rel. unit)
(12) was used as a standard compound in comparative
experiments.
1.0
0.8
0.6
0.4
0.2
1.6
1.4
1.2
In toluene and acetone, both spironaphthopyrans exꢀ
ist virtually entirely as cyclic isomers A (Scheme 3):
their spectra show no noticeable absorption in the visꢀ
ible range, as distinct from acyclic merocyanine strucꢀ
tures B.1,2
4
3
5
1.0
0.8
0.6
0.4
0.2
The spectrum of the cyclic form of spironaphthopyran
12 in toluene contains a structured absorption band with
the maxima at 346 (ε 13 590) and 362 nm (ε 11 930). The
spectrum of compound 11A shows an absorption band at
342 nm (ε 22 150) and, because of the presence of the
heterocyclic substituent, an additional longerꢀwavelength
band at 370 to 420 nm (Fig. 1). In more polar solvents,
the absorption bands undergo a slight hypsochromic shift.
Isomer 11A fluoresces weakly at 430 nm. At 77 K, phosꢀ
phorescence was observed; the maxima of its structured
band appear at 580 and 630 nm. In contrast to 11A, comꢀ
pound 12A show no luminescence. At low temperatures,
both spironaphthopyrans exhibit photochromic properꢀ
ties, which are not observed under normal conditions
2
1
400
500
600
λ/nm
Fig. 2. Photoinduced changes in the absorption spectra of comꢀ
pound 12 upon the irradiation with the light wavelength λ =
365 nm for 0 (1), 30 (2), 60 (3), and 120 s (4) and the fluoresꢀ
cence spectrum of open form 12B (C = 1.13•10–4 mol L–1
toluene, 200 K) (5).
,
because of a highꢀrate reverse thermal reaction of ring
closure. For instance, when irradiated with UV light at
200 K, colorless solutions of spironaphthopyran turned
colored due to the formation of acyclic structures B
(Fig. 2). Under these conditions, both isomers 11B and
12B are stable and intensely fluoresce at 550 to 720 nm;
the spectrum of compound 11B is bathochromically
shifted by 20 nm relative to compound 12B.
Cationꢀinduced isomerization. Addition of equivalent
amounts of Zn2+, Cu2+, Mn2+, Co2+, and Ni2+ salts to a
virtually colorless solution of spironaphthopyran 11 in
acetone significantly changed the spectral pattern. In the
near UV range of the spectrum, the absorption increases
insignificantly, while the visible range contains new inꢀ
tense bands at different λ values, depending on the type of
the ions added (Table 1). The band maxima of metalꢀ
containing solutions of spironaphthopyran are shifted
hypsochromically relative to the band of the merocyanine
isomer. The largest shift (29 nm) was observed for soluꢀ
ε•10–4/L mol–1 cm–1
I (rel. unit)
8
2.5
1
2.0
6
4
2
2
1.5
1.0
0.5
4
5
3
300
400
500
600
λ/nm
Fig. 1. Absorption spectra of compounds 11 (1) and 12 (2), the
fluorescence excitation (3) and emission spectra (4) of comꢀ
pound 12 (toluene, 293 K). The phosphorescence spectrum of
compound 11 (5) (toluene—EtOH—Et2O, 77 K).

708
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 3, March, 2005
Voloshin et al.
Table 1. Spectroscopic properties of merocyanines 11 and 12 and their complexes in acetone
M
11
12
abs
abs
fl
abs
abs
fl
λ
max/nm
–∆λ
λ
max/nm
λ
max/nm
∆λ
λ
max/nm
max
max
—*
Mn
Co
Ni
Cu
Zn
Cd
588
582
571
580
559
566
586
—
620
—
—
—
—
562
—
—
—
—
—
—
—
—
—
–4
—
600
—
—
—
—
6
17
8
29
22
2
625
628
558
—
605
—
* Metalꢀfree.
tions containing Cu2+ ions (Table 1). The reactions of
metal ions with spiropyran 11 are fairly contrast ones.
Addition of alkali and alkalineꢀearth ions even in a
100ꢀfold excess with respect to the spiropyran virtually
did not change the spectral pattern, which indicates that
no complexation occurs. In the presence of Cd2+ ions,
coloration was noticeable only with a 20ꢀfold excess of
the metal. In contrast to compound 11, a solution of
spiropyran 12 changed color only upon addition of a
100ꢀfold excess of Zn2+ ions. The absorption band of the
product also experienced a blue shift relative to the band
of the corresponding merocyanine.
chrome sensitive to the presence of heavy metal cations in
solution.
Experimental
1
H NMR spectra were recorded on a Varian Unityꢀ300 specꢀ
trometer (300 MHz) in CDCl3 at 20 °C; δ values and spinꢀspin
coupling constants were measured to within 0.01 ppm and 0.1 Hz,
respectively.
Electronic absorption spectra were recorded on a Varian,
Carry 100 spectrophotometer. Luminescence emission and exꢀ
citation spectra were recorded on a Shimadzu RFꢀ5001 PC
spectrofluorimeter. The solvents were MeOH, EtOH, MeCN,
acetone, toluene (Aldrich), heptane, and Et2O (reagent grade).
Photolysis of solutions was carried out with a DRShꢀ250 merꢀ
cury lamp with a set of interference light filters for isolation of
the spectral lines of mercury. Metal ions were added to solutions
as perchlorates. The constant ionic strength (µ = 0.01) of photoꢀ
metrically studied solutions was maintained by adding 0.2 M
Bu4NClO4 (Acros).
Spiroheterocyclic photochromes can react with metal
ions in two known ways: either through complexation
between their merocyanine isomers and a metal ion or
through participation in a redox reaction.24 In both cases,
reaction products absorb in the visible range of the specꢀ
trum. Obviously, in contrast to complex formation, a reꢀ
dox process is irreversible. To check the reversibility of
reactions of spironaphthopyran with metal ions, a comꢀ
petitive complexone, namely, a disodium salt of ethyleneꢀ
diaminetetraacetic acid (EDTA), was added to colored
solutions.25 In all cases, the solutions became colorless
and the spectra resumed their original shapes characterꢀ
istic of the cyclic isomer. Hence, the reactions of spiroꢀ
pyrans with metal ions yield complex compounds 11C
and 12C.
Compounds 1,26 5,27 and 12 28 were prepared according to
known procedures.
Methyl 4ꢀformylꢀ3ꢀmethoxyꢀ2ꢀnaphthoate (2). A mixture of
ester 1 (2.30 g, 10 mmol), K2CO3 (1.66 g, 12 mmol), 18ꢀcrownꢀ
6 (0.053 g, 0.2 mmol), and iodomethane (0.75 mL, 12 mmol) in
toluene (35 mL) was refluxed for 10 h. The precipitate was
filtered off, the filtrate was concentrated, and the residue was
purified by column chromatography on Al2O3 with CHCl3 as an
eluent. The solvent was removed and the residue was recrystalꢀ
lized from hexane. The yield of compound 2 was 1.93 g (79%),
m.p. 83—84 °C. Found (%): C, 68.77; H, 5.06. C14H12O4. Calꢀ
culated (%): C, 68.85; H, 4.95. 1H NMR, δ: 4.02 (s, 3 H,
2ꢀCOOCH3); 4.06 (s, 3 H, 3ꢀOCH3); 7.56 (m, 1 H, H(7)); 7.74
(m, 1 H, H(6)); 7.90 (m, 1 H, H(8)); 8.66 (s, 1 H, H(1)); 9.22
(m, 1 H, H(5)); 10.84 (s, 1 H, 4ꢀCHO).
Colored solutions of Zn2+ and Cd2+ complexes with
spironaphthopyran 11 weakly fluoresced at 628 and
625 nm, respectively (see Table 1). In the case of Cu2+
,
Mn2+, Co2+, and Ni2+ complexes, no fluorescence was
observed.
Thus, we developed the method for the synthesis of
3ꢀ(4,5ꢀdiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)ꢀ2ꢀhydroxyꢀ1ꢀnaphthꢀ
aldehyde and 5´ꢀ(4,5ꢀdiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)spiro[inꢀ
dolineꢀ2,3´ꢀnaphthopyran], which exhibits photochromic
properties in solutions at T < 250 K. The merocyanine
form of compound 11 yields intensely colored complexes
with Cu2+, Mn2+, Co2+, Ni2+, Zn2+, and Cd2+ cations.
The spironaphthopyran obtained is of interest as a photoꢀ
4ꢀFormylꢀ3ꢀmethoxyꢀ2ꢀnaphthoic acid (3). A mixture of esꢀ
ter 2 (1.96 g, 8 mmol) and NaOH (0.38 g, 9.5 mmol) was
refluxed in water (8 mL) for 2 h. The reaction mixture was
cooled and acidified with dilute HCl to pH ~2. The precipitate
was filtered off, washed with cold water, and dried. The yield of
compound 3 was 1.80 g (92%), m.p. 199—200 °C (from propanꢀ
2ꢀol—water, 1 : 1). Found (%): C, 67.90; H, 4.46. C13H10O4.
1
Calculated (%): C, 67.82; H, 4.38. H NMR, δ: 4.16 (s, 3 H,

Spiropyrans and spirooxazines
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 3, March, 2005
709
3ꢀOCH3); 7.62 (m, 1 H, H(7)); 7.80 (m, 1 H, H(6)); 7.98 (d,
1 H, H(8), J = 8.1 Hz); 8.93 (s, 1 H, H(1)); 9.21 (d, 1 H, H(5),
J = 8.7 Hz); 10.86 (s, 1 H, 4ꢀCHO).
was purified by column chromatography on Al2O3 with benzene
as an eluent. The yield of compound 11 was 0.29 g (53%),
m.p. 200—201 °C (from heptane—toluene, 3 : 1). Found (%):
C, 83.60; H, 5.36; N, 5.02. C38H30N2O2. Calculated (%):
C, 83.49; H, 5.53; N, 5.12. 1H NMR, δ: 1.25, 1.42 (both s,
3 H each, 3ꢀMe); 2.79 (s, 3 H, 1ꢀMe); 5.90 (d, 1 H, H(2´), J =
10.5 Hz); 6.57 (d, 1 H, H(7), J = 7.7 Hz); 6.89 (td, 1 H,
H(5), J = 7.4 Hz, J = 0.9 Hz); 7.10—7.14 (m, 3 H, H(4),
PhH); 7.20 (td, 1 H, H(6), J = 7.6 Hz, J = 1.2 Hz); 7.22—7.40
(m, 7 H, H(8´), PhH); 7.56 (m, 1 H, H(9´)); 7.60—7.63 (m,
2 H, PhH); 7.66 (d, 1 H, H(1´), J = 10.5 Hz); 7.86 (d,
1 H, H(7´), J = 8.1 Hz); 8.05 (d, 1 H, H(10´), J = 8.5 Hz); 8.61
(s, 1 H, H(6´)).
2ꢀOxoꢀ1,2ꢀdiphenylethyl 4ꢀformylꢀ3ꢀmethoxyꢀ2ꢀnaphthoate
(6). A mixture of acid 3 (2.30 g, 10 mmol) and NaOMe (0.54 g,
10 mmol) was refluxed in MeOH (17 mL) for 1 h. The solvent
was evaporated in vacuo to half the initial volume and ether
(10 mL) was added. The precipitate was filtered off and dried
in vacuo. The yield of sodium salt 4 was 2.24 g (89%). A mixture
of salt 4 (2.52 g, 11 mmol) and PEGꢀ400 (2 mL) in MeCN
(20 mL) was stirred at 70 °C for 0.5 h. Desyl chloride 5 (2.31 g,
10 mmol) was added and the reaction mixture was refluxed with
stirring for 7 h and poured into water with ice (50 mL). The
precipitate that formed was filtered off, washed with water, and
dried. The resulting ester 6 was purified by column chromatoꢀ
graphy on Al2O3 with CHCl3 as an eluent and recrystallized
from heptane—toluene (1 : 1). The yield of compound 6 was
2.46 g (58%), m.p. 161—162 °C. Found (%): C, 76.56; H, 4.87.
C27H20O5. Calculated (%): C, 76.40; H, 4.75. 1H NMR, δ: 4.03
(s, 3 H, 3ꢀOCH3); 7.16 (s, 1 H, 2ꢀCOOR); 7.37—7.47 (m, 5 H,
PhH); 7.50—7.60 (m, 4 H, H(7), PhH); 7.71 (m, 1 H, H(6));
7.90 (m, 1 H, H(8)); 7.98—8.02 (m, 2 H, PhH); 8.78 (s, 1 H,
H(1)); 9.20 (m, 1 H, H(5); 10.81 (s, 1 H, 4ꢀCHO).
This work was financially supported by the Civilian
Research and Development Foundation of the United
States (CRDF) and the Ministry of Education of the Rusꢀ
sian Federation (Project ROꢀ004ꢀX1), the Russian Founꢀ
dation for Basic Research (Project No. 03ꢀ03ꢀ32154),
and the International Scientific and Technical Center
(Grant 2117).
3ꢀ(4,5ꢀDiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)ꢀ2ꢀmethoxyꢀ1ꢀnaphthaldeꢀ
hyde (7). A mixture of desyl naphthoate 6 (2.12 g, 5 mmol) and
ammonium acetate (2.31 g, 30 mmol) was refluxed in acetic
acid (10 mL) for 4 h. The reaction mixture was poured into ice
(100 g). The precipitate was filtered off, washed with water,
dried, and purified by column chromatography on Al2O3 with
CHCl3 as an eluent. The yield of compound 7 was 1.12 g
(55%), m.p. 158—159 °C (from propanꢀ2ꢀol—toluene, 3 : 1).
Found (%): C, 79.84; H, 4.81; N, 3.34. C27H19NO3. Calcuꢀ
lated (%): C, 79.98; H, 4.72; N, 3.45. 1H NMR, δ: 4.12 (s, 3 H,
2ꢀOCH3); 7.37—7.46 (m, 6 H, PhH); 7.55 (m, 1 H, H(6)); 7.70
(m, 1 H, H(7)); 7.72—7.79 (m, 4 H, PhH); 7.93 (m, 1 H, H(5));
8.89 (s, 1 H, H(4)); 9.22 (m, 1 H, H(8)); 10.92 (s, 1 H, 1ꢀCHO).
3ꢀ(4,5ꢀDiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)ꢀ2ꢀhydroxyꢀ1ꢀnaphthaldeꢀ
hyde (8). Anhydrous AlCl3 (2.0 g, 15 mmol) in methylene dichloꢀ
ride (15 mL) was stirred at ~20 °C for 2 h. A solution of aldeꢀ
hyde 7 (2.03 g, 5 mmol) in methylene dichloride (15 mL) was
added dropwise and the reaction mixture was stirred at ~20 °C
for 3 h and poured into dilute HCl. The product was extracted
with chloroform. The solvent was removed and the residue was
purified by column chromatography on Al2O3 with CHCl3 as an
eluent and recrystallized from acetonitrile—benzene (1 : 1). The
yield of compound 8 was 67%, m.p. 213—214 °C. Found (%):
C, 79.93; H, 4.50; N, 3.49. C26H17NO3. Calculated (%):
References
1. N. A. Voloshin, A. V. Metelitsa, J. C. Misheau, E. N.
Voloshina, S. O. Bezugliy, N. E. Shelepin, V. I. Minkin,
V. V. Tkachev, B. B. Safoklov, and S. M. Aldoshin, Izv.
Akad. Nauk, Ser. Khim., 2003, 1929 [Russ. Chem. Bull., Int.
Ed., 2003, 52, 2038].
2. R. Guglielmetti, in Photochromism, Eds H. Dürr and
H. BouasꢀLaurent, Elsevier, Amsterdam, 1990, Ch. 8.
3. R. C. Bertelson, in Organic Photochromic and Thermochromic
Compounds, Vol. 1, Eds J. C. Crano and R. J. Guglielmetti,
Plenum Press, New York, 1999, Ch. 1.
4. S. Kawata and Y. Kawata, Chem. Rev., 2000, 100, 1777.
5. G. Bercovic, V. Krongauz, and V. Weiss, Chem. Rev., 2000,
100, 1741.
6. M. Inouye, Coord. Chem. Rev., 1996, 148, 265.
7. O. A. Fedorova, S. P. Gromov, and M. V. Alfimov, Izv.
Akad. Nauk, Ser. Khim., 2001, 1882 [Russ. Chem. Bull., Int.
Ed., 2001, 50, 1970].
8. K. Kimura, Coord. Chem. Rev., 1996, 148, 41.
9. K. Kimura, Bull. Chem. Soc. Jpn, 2003, 76, 225.
10. L. S. Atabekyan, A.K. Chibisov, and G. P. Roitman,
Zh. Anal. Khim., 1982, 37, 389 [J. Anal. Chem. USSR, 1982,
37 (Engl. Transl.)].
1
C, 79.78; H, 4.38; N, 3.58. H NMR, δ: 7.40—7.47 (m, 7 H,
H(6), PhH); 7.66 (m, 1 H, H(7)); 7.70—7.75 (m, 4 H, PhH);
7.86 (m, 1 H, H(5)); 8.67 (s, 1 H, H(4)); 9.23 (m, 1 H, H(8));
11.04 (s, 1 H, 1ꢀCHO); 12.47 (s, 1 H, 2ꢀOH).
11. K. Chibisov and H. Goerner, Chem. Phys., 1998, 237, 425.
12. L. S. Atabekyan and A. K. Chibisov, Khim. Vys. Energ.,
1998, 30, 35 [High Energy Chem., 1998, 30 (Engl. Transl.)].
13. L. Taylor, J. Nicholson, and R. Davis, Tetrahedron Lett.,
1967, 17, 1585.
14. L. S. Atabekyan, A. I. Lilikin, G. V. Zakharova, and A. K.
Chibisov, Khim. Vys. Energ., 1996, 30, 452 [High Energy
Chem., 1996, 30 (Engl. Transl.)].
15. J. D. Winkler, C. M. Bowen, and V. Michelet, J. Am. Chem.
Soc., 1998, 120, 3237.
16. L. Evans, G. E. Collins, R. E. Shaffer, V. Michelet, and
J. D. Winkler, Anal. Chem., 1999, 71, 5322.
5´ꢀ(4,5ꢀDiphenylꢀ1,3ꢀoxazolꢀ2ꢀyl)ꢀ1,3,3ꢀtrimethylspiro(inꢀ
dolineꢀ2,3´ꢀ[3H]naphtho[2,1ꢀb]pyran) (11). A mixture of perꢀ
chlorate 9 (0.27 g, 1 mmol) and aldehyde 8 (0.39 g, 1 mmol) was
refluxed in glacial acetic acid (8 mL) for 5 h and left at ~20 °C
for 12 h. The precipitate that formed was filtered off, washed
with ether, dried, and used subsequently without additional puꢀ
rification. A flow of dry ammonia was passed through a suspenꢀ
sion of the resulting perchlorate 10 in benzene (20 mL) until the
precipitate dissolved. The solvent was removed and the residue

710
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 3, March, 2005
Voloshin et al.
17. G. E. Collins, L.ꢀS. Choi, K. J. Ewing, V. Michelet, C. M.
Bowen, and J. D. Winkler, Chem. Commun., 1999, 321.
18. Yu. P. Kovtun, Ya. O. Prostota, and A. I. Tolmachev, Dyes
and Pigments, 2003, 58, 83.
24. P. Uznanski, C. Amiens, B. Donnadieu, Y. Coppel, and
B. Chaudret, New J. Chem., 2001, 25, 1486.
25. J. T. C. Wojtyk, P. Kazmaier, and E. Buncel, Chem. Mater.,
2001, 13, 2547.
19. N. A. Voloshin, A. V. Chernyshev, A. V. Metelitsa, S. O.
Besuglyi, E. N. Voloshina, L. P. Sadimenko, and V. I.
Minkin, ARKIVOC, 2004, XI, 16.
20. T. Deligeorgiev, S. Minkovska, B. Jejiazkova, and
S. Rakovsky, Dyes and Pigments, 2002, 53, 101.
21. M. H. Henary and C. J. Fahrni, J. Phys. Chem. A, 2002,
106, 5210.
26. Ashram, S. Mizyed, and P. E. Georghiou, J. Org. Chem.,
2001, 66, 1473.
27. A. M. Ward, in Org. Synth., Coll. Vol. 2, Ed. A. H. Blatt,
1942, 159.
28. R. Wizinger and H. Wening, Helv. Chim. Acta, 1940,
23, 247.W
22. M. Gomez, G. Muller, and M. Rocamora, Coord. Chem.
Rev., 1999, 193—195, 769.
23. D. Davidson, M. Weiss, and M. Jelling, J. Org. Chem.,
1937, 2, 328.
Received November 2, 2004;
in revised form March 9, 2005