Structure and properties of 3,6′-dimethyl-2,3-dihydrospiro[naphtho[1, 3]oxazine-2,2′-[2H]-chromen]-4-ones

Article abstract of DOI:10.1007/s11172-011-0204-x

New spiropyrans of the naphthoxazinone series containing structurally different hetarene moieties were synthesized. The structures of all resulting compounds were preliminary investigated by IR and ¹H NMR spectroscopy. The structures of some of

Full text of DOI:10.1007/s11172-011-0204-x

Russian Chemical Bulletin, International Edition, Vol. 60, No. 7, pp. 1366—1371, July, 2011
1366
Structure and properties of 3,6´ꢀdimethylꢀ2,3ꢀdihydrospiroꢀ
[naphtho[1,3]oxazineꢀ2,2´ꢀ[2H]ꢀchromen]ꢀ4ꢀones
S. M. Aldoshin,a E. L. Mukhanov,b B. S. Lukyanov,b S. O. Bezuglyi,c M. B. Lukyanova,b
A. N. Utenyshev,a V. V. Tkachev,a and V. I. Minkinb,c
aInstitute of Problems of Chemical Physics, Russian Academy of Sciences,
1 prosp. Akad. Semenova, 142432 Chernogolovka, Moscow Region, Russian Federation.
Fax: +7 (496) 522 5636. Eꢀmail: sma@icp.ac.ru
bInstitute of Physical and Organic Chemistry, Southern Federal University,
194/2 prosp. Stachki, 344090 RostovꢀonꢀDon, Russian Federation.
Fax: +7 (863) 243 4177. Eꢀmail: bluk@ipoc.rsu.ru
cSouthern Scientific Center of Russian Academy of Sciences,
41 ul. Chekhova, 344006 RostovꢀonꢀDon, Russian Federation.
Fax: +7 (863) 243 4177. Eꢀmail: lab811@ipoc.rsu.ru
New spiropyrans of the naphthoxazinone series containing structurally different hetarene
moieties were synthesized. The structures of all resulting compounds were preliminary investiꢀ
gated by IR and 1H NMR spectroscopy. The structures of some of the newly synthesized
spiropyrans were completely characterized by Xꢀray diffraction. An analysis of the structures
and photochromic properties of the spiropyrans led to the conclusion about the influence of the
aldehyde group on the photochromic characteristics of spiropyrans.
Key words: spiropyran, photochromism, naphthoxazinone, Xꢀray diffraction study.
Spiropyrans belong to one of the most promising classes
of photochromic compounds, whose electronic absorpꢀ
tion spectra can undergo reversible changes under activatꢀ
ing radiation.1,2 These compounds have attracted interest
due to high sensitivity of their photochromic characterisꢀ
tics to structural variations, as well as because of wide
ranges in which the corresponding spectral and photodyꢀ
namic parameters may vary.3 Hence, these compounds
are attractive for the design of new functional materials.
There is an increasing need in the synthesis and investigaꢀ
tion of new systematic series of spiropyrans with the aim
of revealing structural units, whose modifications can be
used to efficiently control the photochemical behavior of
spiro systems.
Although the photoisomerization of spiropyrans is deꢀ
scribed mainly by structural changes in the benzopyran
moiety, the photodynamic and spectral characteristics of
these compounds depend on the structures of both the
2Hꢀchromene and hetarene parts. To analyze the effect of
πꢀacceptor substituents on the photochromic properties
of spiro systems, we have studied4,5 spiropyrans of the
benzoxazine series 1a and 1b containing the methyl group
in position 6´ of the benzopyran moiety of the molecule.
To investigate the influence of the conjugation system in
the oxazine moiety on the photochemical properties of
spiropyrans, we synthesized compound 1c.6,7
In continuation of investigations on the combined inꢀ
fluence of the benzannulation in the oxazine moiety and
a set of substituents in the benzopyran moiety on the photoꢀ
chromic properties of spiropyrans, in the present study we
synthesized analogs of compounds 1a—c, viz., 3,6´ꢀdiꢀ
methylꢀ2,3ꢀdihydrospiro[naphtho[1,3]oxazineꢀ2,2´ꢀ[2H]ꢀ
chromen]ꢀ4ꢀones 2a—c.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1344—1349, July, 2011.
1066ꢀ5285/11/6007ꢀ1366 © 2011 Springer Science+Business Media, Inc.

Dimethylspiro[naphthoxazine[2H]chromenes]
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 7, July, 2011
1367
Results and Discussion
less of the wavelength of activating radiation. In experiꢀ
ments performed in toluene at 20 °C, solutions of spiroꢀ
pyrans 1a,c and 2a containing the formyl group in posiꢀ
tion 8´ of the benzopyran moiety display photochromic
properties. Under irradiation at λmax = 365 nm, longꢀ
wavelength absorption maxima are observed at λmax = 600
(1c) and 605 nm (2a), which is indicative of the formation
of the open merocyanine isomers (Fig. 1, Table 1).
Formylꢀsubstituted compounds 1c and 2a exhibit
photochromic properties only in solution, whereas they
do not show these properties in the solid state, like related
spiropyran 1a.4 The lifetime of the photoinduced form of
spiropyran 1c is two times longer than that of compound
2a. On the whole, the additionally annulated benzene ring
in the hetarene moiety leads to an increase in the rate of
reverse thermal bleaching reactions and, consequently, to
a decrease in the lifetime of the photoinduced form reꢀ
gardless of the annulation position.
Spiropyrans 2a—c were synthesized by the reaction of
2ꢀformylꢀ4ꢀmethylphenols 3 with 2,3ꢀdimethylꢀ4ꢀoxoꢀ
2,3ꢀdihydronaphtho[1,3]oxazinium perchlorates 4 in aceꢀ
tic acid followed by the treatment of styreneꢀsubstituted
salts 5 with triethylamine (Scheme 1).
The structures of the resulting compounds were conꢀ
firmed by IR and 1H NMR spectroscopy.
The IR spectra of spiropyrans 2a—c show C=C stretchꢀ
ing bands of the pyran ring at 1605—1635 cm–1 and
C=O stretching bands of the naphthoxazine moiety at
1662—1665 cm–1, as well as absorption bands characterꢀ
istic of the CSp—O bond at 970—975 cm–1
.
1
The assignment of the signals in the H NMR specꢀ
trum is based, in part, on the analogy with the earlier
investigations.6,7 The 1H NMR spectra of compounds
2a—c show threeꢀproton singlets of NMe groups at δH 3.2
and of the methyl group of the benzopyran moiety at δH 2.3.
The characteristic doublets for the H(3´) protons at
δH 6.0—6.2 are indicative of the cis configuration of the
corresponding vinyl group in the molecules and confirm
their spirocyclic structure.
We performed photochemical studies of the newly synꢀ
thesized compounds. Spiropyrans 2a—c, like compound
1c synthesized earlier, do not exhibit photochromic propꢀ
erties under irradiation of their ethanolic solutions in
a steadyꢀstate mode at low (–70 °C) temperatures regardꢀ
Unlike compound 1b studied earlier, its benzo analogs
2b,c do not exhibit photochromic activity in solution reꢀ
gardless of the experimental conditions. Taking into
account this behavior, it is of interest to study in detail
their structures, including by means of Xꢀray diffraction.
The investigation of the geometric parameters of the
C
Sp—O bond and the environment of the spirocyclic carꢀ
bon atom can provide additional information on the inꢀ
fluence of the structure of the oxazine and benzopyran
moieties on the efficiency of photoisomerization.
Scheme 1
3a: R1 = —CHO;
3b: R1 = —H;
4a: R2 = 6,7ꢀbenzo;
4b: R2 = 7,8ꢀbenzo;
5a, 2a: R1 = —CHO; R2 = 6,7ꢀbenzo;
5b, 2b: R1 = —H; R2 = 7,8ꢀbenzo;
5c, 2c: R1 = —H; R2 = 6,7ꢀbenzo

1368
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 7, July, 2011
Aldoshin et al.
A
A
a
0.06
0.05
0.04
0.03
0.02
0.01
0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
dt = 0.1 s
400
500
600
700
800 λ/nm
300
400
500
600
700
800
λ/nm
A
b
A
dt = 0.1 s
0.006
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.004
0.002
0
–0.002
500
600
700 800 900 λ/nm
300
400
500
600
700 800 900
λ/nm
Fig. 1. UV absorption spectra of spiropyrans 1c (a) and 2a (b) in toluene before and after steadyꢀstate irradiation at λ
= 365 nm
max
and T = 20 °C; the direction of an increase in the intensity of the longꢀwavelength absorption maximum under irradiation is indicated
by arrows.
The molecular structures of compounds 2b and 2c are
shown in Figs 2 and 3, respectively. In all the aboveꢀ
mentioned compounds, the benzopyran and naphthoxꢀ
azine moieties are approximately orthogonal to each other
and are individually nonplanar. The naphthoxazine moiꢀ
eties in these compounds are bent along the N(3)—O(1)
line by 31.4° and 38.3°, respectively. The benzopyran
moiety is bent along the C(3´)...O(1´) and C(4´)...O(1´)

Dimethylspiro[naphthoxazine[2H]chromenes]
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 7, July, 2011
1369
Table 1. Characteristics of the absorption spectra of spiropyrans
2a—c in toluene at 20 °C compared with the spectra of comꢀ
pounds 1a—c synthesized earlier
a slight pyramidalization of the nitrogen atoms N(3)
and the weaker sp3 character of its lone pair (LP). Simiꢀ
lar values of the aboveꢀmentioned parameters are obꢀ
served for compound 1b: the deviation of the nitrogen
atom from the corresponding plane is 0.16 Å, the sum
of the bond angles at the nitrogen atom is 355.8°. The
LP—N(3)—C(2´2)—O(1´) torsion angle is 1.2 and 5.8° in
compounds 2b and 2c, respectively (3.7° in compound 1b),
which attests that the lone pair of the nitrogen atom
is located almost parallel to the σ* orbital of the
C(2´2)—O(1´) bond. Due to this mutual arrangement,
the orbital interaction between the nꢀlone pair of the
nitrogen atom N(3) and the antibonding orbital of this
bond becomes possible. This should lead to the strengthꢀ
ening of the C(2´2)—N(3) bond and the loosening of the
C(2´2)—O(1´) bond. As mentioned earlier,5 the efficiency
of this interaction depends mainly on the following two
factors: the mutual orientation of the heteroatoms in the
spiro unit and the electronic state of these heteroatoms.
Unlike indoline analogs, in which the lone pair of the
nitrogen atom is conjugated with the π system of the benzꢀ
ene ring (N—CPh = 1.393—1.416 Å), the lone pair of the
nitrogen atom N(3) in compounds 2b,c, as well as in comꢀ
pound 1b, is involved in the more efficient amide conjugaꢀ
tion with the carbonyl group C(4)=O(15), whose π* orbitꢀ
al is lower in energy than the π* orbital of the phenyl
group. This conjugation results in the shortening of the
N(3)—C(4) bond in compounds 2b and 2c to 1.346(6) and
1.372(2) Å, respectively (1.370(2) Å in compound 1b) and
to a decrease in the efficiency of the n—σ* interaction
between the lone pair of the nitrogen atom N(3) and the
σ* orbital of the C(2´2)—O(1´) bond in molecules 2b, 2c,
and 1b compared with the indoline analogs.
Comꢀ Subsꢀ
pound tituent
Closed cyclic
form
Photoinduced
open form
λ
max/nm ε/L mol–1 cm–1
λmax/nm τ/s
1аa
6´ꢀMe
8´ꢀCHO
6´ꢀMe
6´ꢀMe
8´ꢀCHO
6´ꢀMe
8´ꢀCHO
6´ꢀMe
6´ꢀMe
346
336
335
329
342
297
343
300
298
4360
4020
4450
6710
7940
7430
5340
6190
9390
594
564
—
600
—
3.00
—
—
0.89
—
0.50
—
1bb
1c
с
2a
605
—
2bd
2cd
—
—
—
с
с
—
a The compound exhibits photochromic properties both in the
solid state and in solution at –70 °C.
b The compound exhibits photochromic properties only in soluꢀ
tion at –70 °C.
c Is not observed in the experimental conditions.
d The compound does not show photochromic properties reꢀ
garldess of the experimental conditions.
lines by 18.3° and 9.9°, respectively, in compound 2b and
by 19.5° and 9.3° in compound 2c. The O(1), N(3), C(4),
and O(15) atoms in both molecules lie in the planes of the
corresponding naphthalene moieties.
The deviation of the nitrogen atom N(3) from the plane
passing through the C(2´2), C(4), and C(16) atoms is 0.15
and 0.18 Å in compounds 2b and 2c, respectively. This
parameter is at the lower limit of the range of the correꢀ
sponding values (0.34—0.12 Å) for the indoline spiropyrꢀ
ans (ISP) containing the methyl substituent at the nitroꢀ
gen atom studied earlier.8 The sum of the bond angles at
the nitrogen atom N(3) is 356.0 and 355.5° in compounds
2b and 2c, respectively. These values are indicative of
The energy of the σ* orbitals of the C(2´2)—O(1´) and
C(2´2)—O(1) bonds decreases as the polarity increases.
The polarity of the aboveꢀmentioned bonds and the elecꢀ
tronic structure of the O(1) and O(1´) atoms depend on
the degree of the involvement of the oxygen lone pairs in
the conjugation with the π systems of the aromatic groups.
As opposed to compound 1b, the lone pairs of the oxygen
O(15)
C(16)
N(3)
C(4)
C(11)
O(15)
C(16)
C(3´)
C(4´)
N(3)
C(2´2)
C(5)
C(6)
C(4)
C(11)
C(3´)
C(4´)
C(14)
C(2´2)
O(1´)
O(1´)
C(9´)
C(5´)
O(1)
C(5)
C(12)
C(9´)
C(5´)
C(10´)
C(12)
C(7)
C(14)
C(13)
O(1)
C(10´)
C(6)
C(7)
C(10)
C(8´)
C(7´)
C(6´)
C(11´)
C(10)
C(9)
C(13)
C(9)
C(8´)
C(7´)
C(6´)
C(11´)
C(8)
C(8)
Fig. 2. Molecular structure of compound 2b.
Fig. 3. Molecular structure of compound 2c.

1370
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 7, July, 2011
Aldoshin et al.
atoms O(1) in compounds 2b and 2c are involved in the
conjugation with the π systems of the naphthalene rather
than benzene moieties. However, the C(10´)—O(1´) and
C(14)—O(1) bond lengths (1.402(4) and 1.370(4) Å, reꢀ
spectively, in 2b; 1.381(2) and 1.375(2) Å in 2c) are only
slightly different from the corresponding values in 1b
(1.375(2) and 1.370(2) Å). It should be noted that the
C(14)—O(1) bond in compound 2b is shorter than the
C(10´)—O(1´) bond and it is equal, within experimental
error, to the corresponding bonds in compounds 2c
and 1b, i.e., the length of this bond is independent of the
nature of the aromatic group, whose π system is conjuꢀ
gated with the lone pair of the oxygen atom O(1). The
C(2´2)—O(1´) (1.430(4) Å) and C(2´2)—O(1) (1.437(4) Å)
bond lengths in 2b and the C(2´2)—O(1´) (1.428(2) Å)
and C(2´2)—O(1) (1.426(2) Å) bond lengths in 2c,
like those in compound 1b (C(2´2)—O(1´), 1.424(2) Å;
C(2´2)—O(1), 1.423(3) Å), are almost equal and substanꢀ
tially deviate from the range of the corresponding CSp—O
bond lengths in ISP (1.485—1.492 Å). The N(3)—CSp
bond lengths in compounds 2b, 2c, and 1b are 1.428(5),
1.449(2), and 1.445(2) Å, respectively, and are in the range
of CSp—N bond lengths for ISP (1.438—1.497 Å). These
data indicate that the nN—σ*C(2´2)—O(1´) interaction in
compounds 2b,c and in compound 1b is weak compared
with that in the formylꢀsubstituted spiropyran4 and ISP
and it has virtually no effect on the length and strength of
the C(2´2)—O(1´) bond, which, apparently, accounts for
the fact that compounds 2b,c and 1b do not exhibit photoꢀ
chromic properties.
The introduction of electronꢀwithdrawing substituents
into the benzene group of the molecules can increase the
degree of conjugation between the lone pair of the oxygen
atom and the π system of the benzene ring, resulting in the
structural modification of the spiro unit. Actually, as we
have shown earlier,4 the C(2´2)—O(1´) (1.439(2) Å) bond in
the benzopyran moiety of compound 1a, which is the formyl
derivative of 1b, is much longer than the corresponding
C(2´2)—O(1) bond in the benzoxazine moiety (1.405(2) Å)
due to the introduction of the strong πꢀacceptor substituꢀ
ent. As a result, compound 1a displays photochromic propꢀ
erties not only in solution but also in the solid state.4
Therefore, a series of new spiropyrans of the oxazinone
series were synthesized. These compounds differ both by
the set of substituents in the benzopyran moiety of the
molecule and the structure of the oxazine ring. In particuꢀ
lar, the structures of the resulting products and their phoꢀ
tochromic properties depend on the electronic structure
of the substituents in position 8´ of the benzopyran moiety
of the molecule. The presence of the additionally annulatꢀ
ed benzene ring in the oxazine moiety (1c and 2a—c) leads
to a decrease in the quantum yield of the phototransforꢀ
mation due to radiationless deactivation of the excited
state (in particular, due to the intramolecular energy transꢀ
fer from the pyran ring to the oxazine moiety) of spiropyrꢀ
an and, as a consequence, results in destabilization of the
open form. At the same time, the absence of the electronꢀ
withdrawing aldehyde group in compounds 2b,c is an adꢀ
ditional factor responsible for a decrease in the efficiency
of photoisomerization.9 The investigation of the newly
synthesized compounds compared with spiropyrans 1a—c
synthesized earlier showed the influence of the synchroꢀ
nous variation in the structure of both the oxazine and
benzopyran moieties on the photochromic properties. It
was confirmed that the introduction of the additionally
annulated benzene ring into the oxazine moiety leads to
substantial destabilization of the photoinduced open form
and, in the case of compounds 2b and 2c, results in the
complete disappearance of the photochromic properties
regardless of the experimental conditions. The linear
6,7ꢀannulation of the benzene group in the benzoxazine
component (compound 2a) is responsible for the twofold
decrease in the lifetime of the photoinduced open isomer
compared with 7,8ꢀannulation (compound 1c).
Experimental
The IR absorption spectra were recorded on an Excalibur
HE 3100 PC Fourierꢀtransform infrared spectrometer using the
attenuated total internal reflection (ATIR) technique. The elecꢀ
tronic absorption spectra were measured in toluene solutions on
an Agilent 8453 spectrophotometer with the use of a DRShꢀ250
mercury lamp equipped with a standard kit of light filters as
a radiation source. The 1H NMR spectra were recorded on
a Bruker 250 radioꢀfrequency spectrometer (250 MHz) in
a pulsed Fourierꢀtransform mode in deuteriochloroform. The
positions of the signals were determined on the δ scale with
respect to the residual signals of the proton of CDCl3 as the
deuterio solvent.
2,6ꢀDiformylꢀ4ꢀmethylphenol (3a) was synthesized accordꢀ
ing to a known procedure.10
2,3ꢀDimethylꢀ4ꢀoxoꢀ2,3ꢀdihydronaphtho[3,2ꢀe][1,3]oxꢀ
azinium perchlorate (4a) was synthesized from 2,3ꢀhydroxynaphꢀ
thoic acid according to a procedure completely analogous to
that used for the synthesis6 of 4b and was introduced into the
reactions without the preliminary identification.
8´ꢀFormylꢀ3,6´ꢀdimethylꢀ2,3ꢀdihydrospiro[naphtho[3,2ꢀe]ꢀ
[1,3]oxazineꢀ2,2´ꢀ[2H]ꢀchromen]ꢀ4ꢀone (2a). 2,3ꢀDimethylꢀ4ꢀ
oxoꢀ2,3ꢀdihydronaphtho[3,2ꢀe][1,3]oxazinium perchlorate (4a)
(3.25 g, 0.01 mol) was added to a hot solution of 2,6ꢀdiformylꢀ4ꢀ
methylphenol (3a) (1.64 g, 0.01 mol) in acetic acid (15 mL). The
reaction mixture was refluxed for 5 min and then cooled. The
darkꢀbrown precipitate of salt 5a that formed was filtered off,
washed with diethyl ether (3×15 mL), and placed in anhydrous
diethyl ether (50 mL). Then Et3N (1.5 mL, 0.01 mol) was added
dropwise. After 12 h, the diethyl ether was decanted, the solvent
was distilled off, and the yellow oily residue was recrystallized
from ethanol. The yield was 1.04 g (28%), m.p. 151—153 °C
(from EtOH). Found (%): C, 74.44; H, 4.56; N, 3.69. C23H17NO4.
Calculated (%): C, 74.39; H, 4.58; N, 3.77. UV, λmax/nm (ε):
297 (7430). IR, ν/cm–1: 1665 (C=O), 1624 (C=C), 971 (CSp—O).
1H NMR, δ: 2.35 (s, 3 H, C(6´)Me); 3.25 (s, 3 H, N(3)Me); 6.22
(d, 1 H, H(3´), J = 9.8 Hz); 7.05 (d, 1 H, H(4´), J = 9.8 Hz);

Dimethylspiro[naphthoxazine[2H]chromenes]
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 7, July, 2011
1371
7.24 (s, 1 H, H(10)); 7.34 (s, 1 H, H (5´)); 7.42—7.58 (m, 3 H,
H(7), H(8), H(7´)); 7.69 (d, 1 H, H(9), J = 8.2 Hz); 7.98 (d, 1 H,
H(6), J = 8.1 Hz); 8.65 (s, 1 H, H(5)); 9.8 (s, 1 H, CHO).
3,6´ꢀDimethylꢀ2,3ꢀdihydrospiro[naphtho[2,1ꢀe][1,3]oxazineꢀ
2,2´ꢀ[2H]ꢀchromen]ꢀ4ꢀone (2b). 2,3ꢀDimethylꢀ4ꢀoxoꢀ2,3ꢀdiꢀ
hydronaphtho[2,1ꢀe][1,3]oxazinium perchlorate (4b) (3.25 g,
0.01 mol) was added to a hot solution of 2ꢀformylꢀ4ꢀmethylꢀ
phenol (3b) (1.36 g, 0.01 mol) in acetic acid (15 mL). The reacꢀ
tion mixture was refluxed for 5 min and then cooled. The darkꢀ
brown precipitate of salt 5b that formed was filtered off, washed
with diethyl ether (3×15 mL), and placed in anhydrous diethyl
ether (50 mL). Then Et3N (1.5 mL, 0.01 mol) was added dropꢀ
wise. After 12 h, the diethyl ether was decanted and evaporated,
and the yellow oily residue was recrystallized from ethanol.
The yield was 0.82 g (24%), m.p. 162—163 °C (from EtOH).
Found (%): C, 76.89; H, 5.03; N, 4.01. C22H17NO3. Calculatꢀ
ed (%): C, 76.97; H, 4.97; N, 4.08. UV, λmax/nm (ε): 300 (6190).
IR, ν/cm–1: 1662 (C=O); 1634 (C=C); 972 (CSp—O). 1H NMR,
δ: 2.27 (s, 3 H, C(6´)Me); 3.20 (s, 3 H, N(3)Me); 6.11 (d, 1 H,
H(3´), J = 9.7 Hz); 6.64 (d, 1 H, H(8´), J = 8.2 Hz); 6.92—7.14
(m, 3 H, H(4´), H(7´), H(5´)); 7.4 (т, 1 H, H(9), J = 8.1 Hz);
7.5—7.62 (m, 2 H, H(8), H(10)); 7.82 (d, 1 H, H(7), J = 8.2 Hz);
7.96 (d, 1 H, H(6), J = 8.4 Hz); 8.05 (d, 1 H, H(5), J = 8.6 Hz).
3,6´ꢀDimethylꢀ2,3ꢀdihydrospiro[naphtho[3,2ꢀe][1,3]oxazineꢀ
2,2´ꢀ[2H]ꢀchromen]ꢀ4ꢀone (2c) was synthesized by analogy with
compound 2b with the use of 2,3ꢀdimethylꢀ4ꢀoxoꢀ2,3ꢀdihydroꢀ
naphtho[3,2ꢀe][1,3]oxazinium perchlorate (4a). The yield was
0.68 g (20%), m.p. 178—179 °C (from EtOH). Found (%):
C, 76.99; H, 5.09; N, 4.07. C22H17NO3. Calculated (%): C, 76.97;
H, 4.97; N, 4.08. UV, λmax/nm (ε): 298 (9390). IR, ν/cm–1: 1665
(C=O); 1629, 1605 (C=C); 985, 971 (CSp—O). 1H NMR, δ: 2.29
(s, 3 H, C(6´)Me); 3.19 (s, 3 H, N(3)Me); 6.06 (d, 1 H, H(3´),
J = 9.6 Hz); 6.63 (d, 1 H, H(8´), J = 8.1 Hz); 6.90—7.10 (m, 3 H,
H(4´), H(7´), H(5´)); 7.22 (s, 1 H, H(10)); 7.33—7.53 (m, 2 H,
H(7), H(8)); 7.67 (d, 1 H, H(9), J = 8.5 Hz); 7.94 (d, 1 H, H(6),
J = 8.1 Hz); 8.64 (s, 1 H, H(5)).
Colorless transparent crystals of 2c are monoclinic: C22H17NO3,
M = 343.37; a = 6.475(1) Å, b = 25.092(7) Å, c = 10.789(1) Å,
β =100.32(1)°. V = 1724.5(4) Å3, Z = 4, ρ
= 1.322 g cm–3
,
calc
μ(MoꢀKα) = 0.087 mm–1, space group P21/n. The intensities of
3654 reflections were measured in the angle range 2θ ≤ 50° using
the ω/2θꢀscanning technique from a single crystal of dimensions
0.40×0.35×0.35 mm. After rejection of the systematic absences
and merging of equivalent reflections, the Xꢀray data set conꢀ
tained 2796 independent reflections (F2(hkl) and σ(F 2)), of
which 2097 reflections were with F2 > 4σ(F2). The structure was
solved and refined by analogy with 2c. In the last cycle of the
fullꢀmatrix refinement, the absolute shifts of all 236 variable
parameters of structure 2c were smaller than 0.001σ; R1 = 0.041,
wR2 = 0.10 based on 2796 observed reflections with I ≥ 2σ(i);
R2 = 0.061, wR2 = 0.11 based on all measured reflections,
GOF = 1.042. After the refinement, the maximum and miniꢀ
mum difference electron densities were 0.237 and –0.156 e А–3
respectively.
,
This study was financially supported by the Federal
Target Program "Scientific and ScientificꢀPedagogiꢀ
cal Personnel of the Innovative Russia in 2009—2013"
(Government Contract No. P1473) and the Council on
Grants at the President of the Russian Federation (Proꢀ
gram for State Support of Leading Scientific Schools of
the Russian Federation, Grant NShꢀ3233.2010.3).
References
1. H. BouasꢀLaurent, H. Dürr, Pure Appl. Chem., 2001, 73, 639.
2. V. I. Minkin, Chem. Rev., 2004, 104, 2751.
3. R. C. Bertelson, in Organic Photochromic and Thermochromic
Compounds, Vol. 1: Photochromic Families, Eds J. C. Crano,
R. J. Guglielmetti, Plenum Press, New York, 1999, p. 85.
4. B. B. Safoklov, B. S. Lukyanov, A. O. Bulanov, A. V. Meꢀ
telitsa, V. I. Minkin, V. V. Tkachev, S. M. Aldoshin, Izv.
Akad. Nauk, Ser. Khim., 2002, 431 [Russ. Chem. Bull.,
Int. Ed., 2002, 51, 462].
5. S. M. Aldoshin, A. O. Bulanov, V. A. Kogan, B. S. Lukyaꢀ
nov, V. I. Minkin, V. V. Tkachev, Dokl. Akad. Nauk, 2003,
390, 51 [Dokl. Chem. (Engl. Transl.), 2003, 390, 107].
6. E. L. Mukhanov, Yu. S. Alekseenko, B. S. Lukyanov, Yu. I.
Ryabukhin, O. N. Ryashchin, M. B. Lukyanova, Khim.
Geterotsikl. Soedin., 2006, 458 [Chem. Heterocycl. Compd.
(Engl. Transl.), 2006, 42, 408].
7. E. L. Mukhanov, Yu. S. Alekseenko, B. S. Lukyanov, V. I.
Minkin, S. O. Bezuglyi, A. N. Utenyshev, V. V. Tkachev,
S. M. Aldoshin, Khim. Geterotsikl. Soedin., 2009, 273 [Chem.
Heterocycl. Compd. (Engl. Transl.), 2009, 45, 219].
8. A. V. Dzyabchenko, Kristallografiya, 1983, 28, 788 [Sov. Phys.
Crystallogr. (Engl. Transl.), 1983, 28].
Xꢀray diffraction study. The unit cell parameters of the crysꢀ
tals of 2b and 2c were determined and threeꢀdimensional sets of
intensities were measured on a Bruker Рꢀ4 automated diffractoꢀ
meter (MoꢀKα radiation, graphite monochromator) at ∼20 °C.
Colorless transparent crystals of 2b are orthorhombic:
C22H17NO3, M = 368.45; a = 6.454(1) Å, b = 14.106(2) Å,
c = 19.332(3) Å, V = 1760.0(5) Å3, Z = 4, ρ
=1.296 g cm–3
,
calc
μ(MoꢀKα) = 0.087 mm–1, space group P212121. The intensities
of 2188 reflections were measured in the angle range 2θ ≤ 50° by
the ω/2θꢀscanning technique from a single crystal of dimensions
0.42×0.38×0.36 mm. After rejection of the systematic absences
and merging of equivalent reflections (R(int) = 0.018), the Xꢀray
data set contained 2012 independent reflections (F2(hkl) and
σ(F 2)), of which 1038 reflections were with F 2 > 4σ(F 2).
The structure was solved by direct methods with the use of the
SHELXTL program package11 and refined by the fullꢀmatrix
leastꢀsquares method with anisotropic displacement parameters
for nonhydrogen atoms against F2 using the SHELXL program
package.11 In the crystal structure of 2b, all H atoms were locatꢀ
ed in difference Fourier maps, and then the coordinates and
isotropic thermal parameters for all H atoms were refined by the
leastꢀsquares method using a riding model.11 The final refineꢀ
ment parameters were R1 = 0.034, wR1 = 0.068, R2 = 0.092,
wR2 = 0.093, GOF = 1.021. The maximum and minimum differꢀ
ence electron densities were 0.112 and –0.112 e А–3, respectively.
9. S. M. Aldoshin, Usp. Khim., 1990, 59, 1144 [Russ. Chem.
Rev. (Engl. Transl.), 1990, 59].
10. F. Ullmann, K. Brittner, Ber. Deutsch. Chem. Ges., 1909,
42, 2539.
11. G. M. Sheldrick, SHELXTL v. 6.14, Structure Determination
Software Suite, Bruker AXS, Madison, Wisconsin, USA,
8/06/2000.
Received March 4, 2011;
in revised form June 17, 2011