Tetracarbonyl systems: VII. Reactions of 1,3,4,6-tetracarbonyl compounds with o-aminothiophenol in the synthesis of regioisomeric 3(2)-aroylmethylene-1, 4-benzothiazin-2(3)ones

Article abstract of DOI:10.1023/B:RUJO.0000003166.58756.fa

In reaction of 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-1,6-diones with o-aminothiophenol (3Z)-3-aroylmethylene-3,4-dihydro-2H-1,4-benzothiazin-2-ones were obtained in a preparative yield. In solution of the latter compounds an enamine-imine tautomerism was observed. In reaction of ethyl esters or amides of 2-substituted 6-aryl-3,4-dihydroxy-6-oxo-2,4-hexadienoic acids with the o-aminothiophenol regioisomeric 2-aroylmethylene-2H-1,4-benzothiazin-3(4H)-ones were formed.

Full text of DOI:10.1023/B:RUJO.0000003166.58756.fa

Russian Journal of Organic Chemistry, Vol. 39, No. 6, 2003, pp. 863 868. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 6, 2003,
pp. 912 917.
Original Russian Text Copyright
2003 by V. Kozminykh, Igidov, E. Kozminykh.
Tetracarbonyl Systems: VII.* Reactions of 1,3,4,6-Tetracarbonyl
Compounds with o-Aminothiophenol in the Synthesis
of Regioisomeric 3(2)-Aroylmethylene-1,4-benzothiazin-2(3)ones
V. O. Kozminykh, N. M. Igidov, and E. N. Kozminykh
Perm State Pharmaceutical Academy, Perm, 614051 Russia
Received April 3, 2002
Abstract In reaction of 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-1,6-diones with o-aminothiophenol
(3Z)-3-aroylmethylene-3,4-dihydro-2H-1,4-benzothiazin-2-ones were obtained in a preparative yield. In
solution of the latter compounds an enamine-imine tautomerism was observed. In reaction of ethyl esters or
amides of 2-substituted 6-aryl-3,4-dihydroxy-6-oxo-2,4-hexadienoic acids with the o-aminothiophenol
regioisomeric 2-aroylmethylene-2H-1,4-benzothiazin-3(4H)-ones were formed.
Heterocyclic derivatives of 1,6-diaryl-3,4-dihydr-
oxy-2,4-hexadiene-1,6-diones (I: tautomeric forms
A, B, and C) forming at their dehydration 5-aryl-2-
aroylmethylene-2,3-dihydrofuran-3-ones (II) [2 4]
are known to readily react with o-aminothiophenol
affording biologically active 2,3-bisaroylmethylene-
2,3-dihydro-4H-1,4-benzothiazines (III) (Scheme 1)
[4 6].
hydro-2H-1,4-benzothiazin-2-one (IVc) by treating a
copper salt of methyl pentafluorobenzoylpyruvate
with
o-aminothiophenol
hydrochloride
[10]
(Scheme 2).
An o-hydroxyphenylamide of 2,4-dioxo-3-(3-oxo-
2,3-dihydro-4H-1,4-benzothiazin-2-ylidene)-4-p-tolyl-
butanoic acid (VII) was also prepared by reaction of
3-p-toluoyl-1,2-dihydro-4H-pyrrolo[5,1-c][1,4]-
Attempts to obtain benzothiazines III by direct
reaction of tetraketones I with the o-aminothiophenol
failed [4, 6]. In reaction of compounds Ia, b with the
latter reagent under relatively mild conditions (short
heating in acetic acid) we isolated with a preparative
benzoxazine-1,2,4-trione with o-aminothiophenol
[11]. Prior to our studies [7 9, 12 14] no other
acylmethylene derivatives of 1,4-benzothiazines were
known. Therefore we should point out that the data
on the synthesis of 2-aroylmethylene-2H-1,4-benzo-
thiazin-3(4H)-ones VI by reaction of aroylpyruvic
acids or 5-aryl-2,3-dihydrofuran-2,3-diones with
o-aminothiophenol [15 18] are not reliable.
According to our data these reactions gave rise only
to precursors of thiazines VI, 4-aryl-2-o-mercapto-
phenylamino-4-oxo-2-butenoic acids VIII, and to
cyclic O,S-acetals, 2-aroylmethyl-2-hydroxy-2H-1,4-
benzothiazin-3(4H)-ones IX, and under more
stringent conditions 1,4-benzothiazin-2,3-dione (X)
was isolated [7, 8, 12, 13]. We also established that
2-dibenzoylmethylene-2H-1,4-benzothiazin-3(4H)-one
XI resulted from the reaction between 4-benzoyl-5-
phenyl-2,3-dihydrofuran-2,3-dione and o-amino-
phenol [7, 8, 12 14] (Scheme 2).
yield
(3Z)-3-aroylmethylene-3,4-dihydro-2H-1,4-
benzothiazin-2-ones (IVa, b: tautomers D and E)
(Scheme 1).
Note that apart from our preliminary communica-
tions [7 9] no published data exist on reaction with
the o-aminophenol of tetracarbonyl systems contain-
ing simultaneously and dioxo fragments.
In the course of detailed investigation of reactions
between tetracarbonyl compounds and o-aminophenol
we also established that at treatment with this reagent
of ethyl esters or amides of 2-substituted 6-aryl-3,4-
dihydroxy-6-oxo-2,4-hexadienoic acids Va c arose
regioisomeric compounds 2-aroylmethylene-2H-1,4-
benzothiazin-3(4H)-ones (VIa, b) (Scheme 2).
Compounds synthesized IVa, b and VIa, b are
yellow crystalline substances insoluble in water,
sparingly soluble in ethanol, ethyl acetate, and soluble
in DMSO.
It should be noted that 3(2)-acylmethylene deriv-
atives of 1,4-benzothiazin-2(3)ones are poorly known
and almost not studied. For instance, a synthesis was
reported of 3-pentafluorobenzoylmethylene-3,4-di-
Spectral parameters of (3Z)-3-aroylmethylene-3,4-
dihydro-2H-1,4-benzothiazin-2-ones (IV) are con-
*
For communication VI see [1].
1070-4280/03/3906-0863$25.00 2003 MAIK Nauka/Interperiodica

864
KOZMINYKH et al.
Scheme 1.
Ar = C6H5 (Ia, IVa), 4-CH3C6H4 (Ib, IVb).
sistent with their assumed structure. We compared
these data with spectral characteristics of a known and
similar in structure (3Z)-3-benzoylmethylene-3,4-di-
hydro-2H-1,4-benzoxazin-2-one (XIIa) [4, 18 20].
The spectra of the regioisomeric 2-aroylmethylene-
2H-1,4-benzothiazin-3(4H)-ones (VIa, b) also are in
good agreement with their assumed structure.
ing vibrations of the carbonyl C2= O from lactone are
located at considerably higher frequencies,
at 1754 cm , and this is also consistent with the
1
classical data [22]. In the IR spectrum of 1,4-benzo-
thiazin-3(4H)-one VIa regioisomeric to compound
IVa are present the characteristic bands of stretching
vibrations of amide group NH from lactam unit at
1
3228 cm and of carbonyl from this amide group
In the crystalline state compounds IV exist in the
enamine structure IVd containing NH-chelate frag-
ment with an intramolecular hydrogen bond of the
1
at 1668 cm , and also the band of stretching vibra-
tions of carbonyl group from the conjugated benzoyl
1
fragment at 1616 cm ; these data support the
type N H
O = C < [21]. It is evidenced in
assumed structure of compound VIa.
particular by the presence in the 1,4-benzothiazine
IVa IR spectrum of a broad low-frequency band
corresponding to the stretching vibrations of the
carbonyl group from the conjugated aroyl unit of the
In the 1H NMR spectra of 1,4-benzothiazines
IVa, b recorded in DMSO-d6 a presence of two
equilibrium tautomers was revealed: the prevailing
enamine (IVD, respective content 74 and 76%) with
characteristic signals of methine proton CH at 7.41
and 7.48 ppm, and imine (IV E, respective content 26
and 24%) characterized by singlets from two protons
of CH2 group at 4.92 and 5.06 ppm respectively. The
N4H group proton did not appear in the spectra,
and in the published data on the spectrum of the
1
NH-chelate at 1590 1630 cm . In this range occur
also the low-frequency stretching vibrations of the
carbonyl C2= O from thiolactone in agreement with
the well-known data [22]. Note for comparison that in
the IR spectrum of 1,4-benzoxazine XIIa the absorp-
tion band of the NH-chelate appears in a similar
1
frequency range, at 1590 1602 cm , and the stretch-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 6 2003

TETRACARBONYL SYSTEMS: VII.
865
Scheme 2.
Ar = C6H5 (Va, Vc, VIa), 4-CH3C6H4 (Vb, VIb); X = CO2Et (Va, Vb), C N (Vc).
1
fluorine-containing analogous compound IVc the
signal of the amino group of the ring was mention-
ed as diffuse downfield resonance at 13.6 ppm [10].
The characteristic signal of the methine CH proton
in the spectra of the enamine form of compounds IV
is shifted downfield by 0.5 ppm as compared with the
corresponding signal in compound XIIa (6.91 ppm)
due to stronger shielding from sulfur than oxygen
atom in the heterocycle. Therewith it should be noted
that unlike 1,4-benzothiazines IV in solutions of
(3Z)-3-aroylmethylene-3,4-dihydro-2H-1,4-benzox-
azin-2-ones (XII) the imine form in the ring (C3= N 4)
is lacking [4, 20, 23] or appears in a negligible
amount, from fractions of percent to 1 2% in acid
medium [23, 24]. At the same time in the H NMR
spectra of similar in structure (3Z)-3-aroylmethylene-
1,2,3,4-tetrahydroquinoxalin-2-ones (XIII) also
registered in DMSO-d6 the imine tautomer was
observed in considerable amount (3 5%) [21]. Thus
in going from 2-oxo derivatives of 1,4-benzoxazine
XII through quinoxalin-2-ones XIII to 1,4-benzothi-
azin-2-ones IV the equilibrium amount of imine form
in solution significantly grows (Scheme 2).
Note also that at addition to the solution of com-
pounds IVa, b in DMSO-d6 of trifluoroacetic acid the
positions of proton signals in the spectra almost did
not change, and the content of tautomers IV D and
IVE also remained the same as before.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 6 2003

866
KOZMINYKH et al.
The signal of methine CH proton in the H1 NMR
tetraketones I affording intermediates F or G follow-
ed by hydrolytic cleavage of aryl methyl ketones
from the intermediate cyclic O,S-acetal G (Scheme1).
In a similar way may occur attack of the most
electrophilic site C3 in substrates V with subsequent
heterocyclization and elimination of ethyl malonamide
or respectively cyanoacetamide furnishing regioiso-
meric compounds VI.
spectra of 1,4-benzothiazines VIa, b taken in
DMSO-d6 solution ( 8.23 and 8.24 ppm respective-
ly) is located downfield (by 0.8 ppm on the average)
from the corresponding signal in the spectra of com-
pounds IV and thus is a distinguishing characteristic.
Besides the spectra of compounds VIa, b contain
characteristic signals of amide proton N4H of the ring
at 11.60 and 11.62 respectively; this signal is lack-
ing in the spectra of 1,4-benzothiazines IV. Regretful-
ly, no comparable compounds as were chosen for
1,4-benzothiazines IV were known for derivatives VI:
2-aroylmethylene-3,4-dihydro-2H-1,4-benzoxazines
did not exist.
Obtained compounds IV and VI exhibit bacterio-
static activity with respect to strains Staphylococcus
aureus P-209 and Escherichia coli M17 [8, 26]; there-
with the regioisomer IVa is highly active.
EXPERIMENTAL
It should be noted in connection with interpretation
of the 1H NMR spectra that at the synthesis of
1,4-benzothiazines IV and VI a thorough purification
of crude products is required from the impurities of
the initial 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-
1,6-diones (Ia, b) or ethyl esters or amides of 2-sub-
stituted 6-aryl-3,4-dihydroxy-6-oxo-2,4-hexadienoic
acids (Va c): The initial compounds tend to crystal-
lize together with products. The purity of compounds
IV is checked by the lack of the characteristic signal
of coupled geminal protons of CH2 group belonging
to the ring 3-oxofuran form I C of the initial 1,3,4,6-
tetraketones in the 1H NMR spectra registered in
DMSO-d6. For instance, the corresponding impurity
of the initial compound Ia (ring form I C, 53%) is
identified by two doublets at 3.48 and 3.95 ppm, J
CH2gem 14.0 Hz [25]. The purity of compounds VI is
checked by the lack of characteristic ethyl group
signals from the ester fragment of compounds Va, b
at 1.22 1.24 ppm (t) and 4.18 4.20 ppm (q), or by
the lack of signals from the amide group protons of
compound Vc located upfield (8.83 10.33 ppm) from
the signal of the N4H group in the ring of products
VIa, b [1].
IR spectra were recorded on spectrophotometers
UR-20 and Specord M-80 from mulls in mineral oil.
1H NMR spectra were registered on spectrometers
Bruker AC-300 (300.13 MHz) and Bruker DRX-500
(500.13 MHz) from solutions in DMSO-d6, internal
reference TMS. Mass spectra were measured on
Kratos MS-30 instrument (Great Britain) with direct
admission of the sample into the ion source (electron
impact), emission current 1000 mA, ionizing voltage
70eV, vaporizer temperature 100 150 C.
The homogeneity of compounds was proved by
TLC on Silufol UV-354 plates in a system benzene
ethyl ether acetone (10: 9: 1), development in iodine
vapor.
The initial 1,6-diaryl-3,4-dihydroxy-2,4-hexadi-
ene-1,6-diones (Ia, b) were obtained by Claisen
condensation of the appropriate aryl methyl ketones
with diethyl oxalate in the presence of sodium methyl-
ate [25]. Ethyl esters and amides of 2-substituted
6-aryl-3,4-dihydroxy-6-oxo-2,4-hexadienoic
acids
(Va c) were prepared by procedure [1]. (3Z)-3-Benzo-
ylmethylene-3,4-dihydro-2H-1,4-benzoxazin-2-one
(XIIa) was obtained by reaction between 3,4-dihydr-
oxy-1,6-diphenyl-2,4-hexadiene-1,6-dione (Ia) with
o-aminophenol [20].
The fragmentation of regioisomeric 1,4-benzothi-
azines IV and VI under the electron impact occurs as
expected with ejection of aroyl and aroylmethylene
fragments to form relatively stable ions with a core
of oxobenzothiazines. Unexpectedly decomposition of
compounds IV and V involves the decarbonylation of
molecular ions to afford relatively abundant (15
51%) ions [M CO]+ . The peaks of molecular ions in
the mass spectra of compound IV and VI are also of
considerable intensity (34 84%) evidencing their
relative stability against the electron impact.
(3Z)-3-Aroylmethylene-3,4-dihydro-2H-1,4-
benzothiazin-2-ones (IVa, b). A mixture of 2 mmol
of an appropriate 1,6-diaryl-3,4-dihydroxy-2,4-hexa-
diene-1,6-dione (Ia, b) and 0.25 g (2 mmol) of
o-aminothiophenol was heated at stirring in 10 20 ml
of acetic acid till dissolution of reagents, then the
reaction mixture was boiled for 1 3 min (TLC
monitoring). After 3 5 h the separated precipitate was
filtered off and recrystallized from ethanol. The
obtained target compounds IVa, b are yellow crystal-
line substances.
The formation of 1,4-benzothiazines IV is likely to
originate from the primary nucleophilic attack of the
amino group of o-aminophenol at the C3 (or C4
(3Z)-3-Benzoylmethylene-3,4-dihydro-2H-1,4-
benzothiazin-2-one (IVa). Yield 0.40 g (71%), mp
with equal probability) in the dienol form of 1,3,4,6-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 6 2003

TETRACARBONYL SYSTEMS: VII.
867
1
154 155 C. IR spectrum,
,
cm : 1590 1630
2-Aroylmethylene-2H-1,4-benzothiazin-3(4H)-
ones (VIa, b). A mixture of 5.0 mmol of an ap-
propriate ethyl 6-aryl-3,4-dihydroxy-2-carbamoyl-6-
oxo-2,4-hexadienoate (Va, b) or 1.29 g (5.0 mmol)
of 3,4-dihydroxy-6-oxo-6-phenyl-2-cyano-2,4-hexa-
dienoic acid amide (Vc) and 0.63 g (5 mmol) of
o-aminothiophenol was heated at stirring in 30 50 ml
of acetic acid till dissolution of reagents, then the
reaction mixture was boiled for 1 3 min [procedure
(a)] or heated at stirring in 80 100 ml of ethanol till
dissolution of reagents and then heated at reflux for
2 3 h (procedure (b) (TLC monitoring). After 5 7 h
the separated precipitate was filtered off and recrystal-
lized from dioxane. The obtained target compounds
VIa, b are yellow crystalline substances.
(C2=O, C6H5CO in NH-chelate), 1582, 1560, 1540,
1460, 1378, 1300. H NMR spectrum (DMSO-d6), ,
1
ppm: 5.06 s [2H, CH2, imine (IV E), 26%], 7.48 s
[1H, CH , enamine (IV D), 74%], 7.57 7.70 and
8.03 8.28 m (9H, C6H5, C6H4). Proton signal from
N4H group lacks in the spectrum (in the spectrum of
IVc analog is present a diffuse downfield signal at
13.6ppm[10]). Mass spectrum, m/z (Irel, %), ion
peaks with I> 5% are listed: 282 (7) [M+H]+ ,
281 (34) [M]+ , 253 (20) [M CO]+ , 252 (13) [M
+
+
CO H] , 236 (7), 162 (10) [M C6H5COCH2] or
2-Benzoylmethylene-2H-1,4-benzothiazin-3(4H)-
one (VIa). Yield 0.51 g (36%) [procedure (a)], from
compound Va), 0.90 g (64%) [procedure (b)], from
compound Va), 0.76 g (54%) [procedure (b)], from
+
150 (14) [C7H4NOS] or
1
compound Vc), mp279 280 C. IR spectrum, , cm :
3228
(CONH),
1668
(CONH),
1616
(C6H5COCH= ), 1592, 1576, 1532, 1504, 1460,
1378, 1256, 1232. H NMR spectrum (DMSO-d6), ,
147 (14), 136 (7), 135 (26), 134 (11), 131 (11), 108
(10), 106 (8), 105 (100) [C6H5 C O]+ , 102 (36),
77 (56) [C6H5]+ , 75 (5), 69 (46), 65 (5). Found, %:
C 68.62; H 4.25; N 5.17. C16H11NO2S. Calculated,
%: C 68.31; H 3.94; N 4.98.
1
ppm: 7.12 7.31, 7.47 7.65 and 8.03 m (9H, C6H5,
C6H4), 8.23 s (1H, CHCOPh), 11.62 s (1H, NH).
Mass spectrum, m/z (Irel, %), ion peaks with I > 5%
are listed: 282 (8) [M+ H]+ , 281 (37) [M]+ , 254 (5),
253 (29) [M CO]+ , 252 (26) [M CO H]+ , 220 (7),
204 (16) [M C6H5]+ $o, 176 (26) [M C6H5CO]+ ,
147 (15), 131 (11), 129 (9), 127 (8), 121 (7), 106 (7),
105 (80) [C6H5 C O]+ , 104 (9), 96 (5), 90 (6),
89 (6), 78 (11), 77 (100) [C6H5]+ , 76 (7), 69 (12),
65 (6). Found, %: C 68.15; H 3.87; N 4.91.
C16H11NO2S. Calculated,%: C 68.31; H3.94; N4.98.
(3Z)-3-p-Methylbenzoylmethylene-3,4-dihydro-
2H-1,4-benzothiazin-2-one (IVb). Yield 0.38 g
1
(64%), mp 144 145 C. H NMR spectrum (DMSO-
d6), , ppm: 2.46 s [3H, CH3, enamine (IV D), 76%],
2.52 s [3H, CH3, imine- (IV E), 24%], 4.92 s [2H,
CH2, (IV E)], 7.41 s [1H, CH , (IV D)], 7.36, 7.58
7.63 and 7.97 8.17 m (8H, 2C6H4). Proton of signal
from N4H group lacks in the spectrum. Mass spec-
trum, m/z (Irel, %), ion peaks with I > 5% are listed:
296 (11) [M+ H]+ , 295 (62) [M]+ , 267 (15) [M
CO]+ , 266 (18) [M CO H]+ , 250 (11), 162 (18)
2-p-Methylbenzoylmethylene-2H-1,4-benzothi-
azin-3(4H)-one(VIb). Yield 0.47 g (32%) (procedure
a, from compound Vb), 0.71 g (48%) (procedure b,
1
from compound Vb), mp 267 268 C. H NMR spec-
+
[M 4-CH3C6H4COCH2] or
trum (DMSO-d6), , ppm: 2.41 s (3H, CH3),
7.12 t, 7.18 d, 7.29 t, 7.38 d, 7.48 d, 7.92 d
(8H, 2 C6H4), 8.24 s (1H, CHCOC6H4CH3-4),
11.60 s (1H, NH). Mass spectrum, m/z (Irel, %),
ion peaks with I > 5% are listed: 297 (6) [M+
2H]+ , 296 (14) [M+ H]+ , 295 (84) [M]+ , 268
(11), 267 (51) [M CO]+ , 266 (72) [M CO
H]+ , 252 (5) [M CO CH3]+ , 250 (5) [M
CO CH3 H]+ , 234 (20), 204 (12) [M
C6H4CH3-4]+ , 176 (18) [M 4-CH3C6H4CO]+ ,
175 (14), 148 (15), 143 (6), 134 (7), 133 (10), 126
(15), 121 (5), 120 (7), 119 (59) [4-CH3C6H4C O]+ ,
104 (5), 92 (7) , 91 (100) [4-CH3C6H4]+ , 89 (13),
77 (9), 69 (6), 65 (45). Found, %: C 69.32;
H 4.22; N 4.91. C17H13NO2S. Calculated, %:
C 69.13; H 4.44; N 4.74.
+
161 (22), 151 (57) [C7H5NOS] or
+
136 (9), 135 (24), 134 (21) [4-CH3C6H4COCH3] ,
120 (6), 119 (67) [4-CH3C6H4C O] , 117 (11),
116 (100) [4-CH3C6H4C CH] , 108 (11), 91 (39)
[4-CH3C6H4] , 77 (9), 69 (58), 65 (18).
Found, %: C 68.85; H 4.63; N 4.59. C17H13NO2S.
Calculated, %: C 69.13; H 4.44; N 4.74.
+
+
+
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 6 2003

868
KOZMINYKH et al.
(3Z)-3-benzoylmethylene-3,4-dihydro-2H-1,4-
13. Sof,ina, O.A., Koz,minykh, V.O., Igidov, N.M.,
Trapeznikova, N.N., and Koz,minykh, E.N.,
Abstracts of Papers, Dokl. uchastnikov shkoly
molodykh uchenykh (Reports of Participents of the
Workshop of Young Researches), Moscow: Izd.
MSKhA, 2000, p. 110.
benzoxazin-2-one (XIIa) [4, 18 20]. IR spectrum,
1
, cm : 1754 (C2= O lactone), 1590 1602 (C6H5CO
1
in NH-chelate). H NMR spectrum (DMSO-d6),
,
ppm: 6.91 s (1H, CHCOPh), 7.13 7.24, 7.55,
8.03 m (9H, C6H5, C6H4), 12.86 s (1H, NH).
14. Trapeznikova, N.N., Cand. Sci. (Chem.) Disserta-
tion, Perm,, 2002, p. 18.
REFERENCES
15. Andreichikov, Yu.S., Tendryakova, S.P., Nalimo-
va, Yu.A., USSR Inventor,s Certificate 615071, 1975;
1. Koz,minykh, V.O., Igidov, N.M., and Kasatki-
na, Yu.S., Zh. Org. Khim., 2001, vol. 37, p. 1604.
2. Poje, M. and Balenovic, K., J. Heterocycl. Chem.,
1979, vol. 16, p. 417.
SSSR Otkrytiya, izobreteniya, 1978, p.
Chem. Abstr., 1978, vol. 89, p. 129528.
26, p. 76;
16. Andreichikov, Yu.S., Tendryakova, S.P., Nalimo-
va, Yu.A., Voronova, L.A., and Vilenchik, Ya.M.,
USSR Inventor,s Certificate 630254, 1976; SSSR
Otkrytiya, izobreteniya, 1978, no. 40, p. 78; Ref. Zh.
Khimiya, 1979, no. 12, 12O162P.
17. Andreichikov, Yu.S., Tendryakova, S.P., Nalimo-
va, Yu.A., and Oronova, L.A., Khim.Getyerotsikl.
Soed., 1977, no. 6, p. 755.
18. Shurov, S.N. and Andreichikov, Yu.S., Khimiya
pyatichlennykh 3-dioksogeterotsiklov (Chemistry of
Five-Membered Dioxo Heterocycles), Perm,: Izd.
Perm. Gos. Univ., 1994, p. 5; Chem. Abstr., 1996,
vol. 125, p. 195292b.
3. Kozminykh, V.O., Igidov, N.M., Kozminykh, E.N.,
and Aliev, Z.G., Pharmazie, 1993, vol. 48, p. 99.
4. Koz,minykh, E.N., Doctoral Sci. (Chem.) Dissertation,
Perm,, 1999, p. 44.
5. Igidov, N.M., Koz,minykh, E.N., Shavkunova, G.A.,
and Koz,minykh, V.O., Abstracts of Papers, Int. Sci.
Conf. on Trends of Natural Sciences on West Ural),
Perm: Izd. Perm. Gos. Univ., 1996, vol. 1, p. 40.
6. Koz,minykh, E.N., Igidov, N.M., Koz,minykh, V.O.,
Shavkunova, G.A., and Sof,ina, O.A., Zh. Org.
Khim., 2000, vol. 36, p. 1381.
7. Sof,ina, O.A., Koz,minykh, E.N., Igidov, N.M.,
Trapeznikova, N.N., and Koz,minykh, V.O.,
Abstracts of Papers, Yubileinaya mezhvuzovskaya
nauchn.-prakt. konf., posvyashchennoi 275-letiyu
goroda Permi i 80-letiyu farmatsevticheskogo obra-
zovaniya na Urale, Perm: Izd. Perm. Gos. Tekhnich.
Univ., 1998, p. 56.
19. Andreichikov, Yu.S., Voronova, L.A., and Milyu-
tin, A.V., Zh. Org. Khim., 1979, vol. 15, p. 847.
20. Koz,minykh, E.N., Igidov, N.M., Shavkunova, G.A.,
Koz,minykh, V.O., Izv. Akad. Nauk, Ser. Khim.,
1997, p. 1340.
21. Sof,ina, O.A., Igidov, N.M., Koz,minykh, E.N.,
Trapeznikova, N.N., Kasatkina, Yu.S., and Koz,mi-
nykh, V.O., Zh. Org. Khim., 2001, vol. 37, p. 1067.
22. Bellamy, L.J., Advances in Infra-red Group Fre-
quencies, London: Methuen, 1966. Translated under
the title Novye dannye po IK spektram slozhnykh
molekul, Moscow: Mir, 1971, p. 177.
8. Koz,minykh, V.O., Igidov, N.M., Sof,ina, O.A., and
Trapeznikova, N.N., Sbornik nauchn. trudov Novye
dostizheniya v khimii karbonil,nykh i geterotsikli-
cheskikh soedinenii (Collection of Sci. Materials on
Heterocyclic Compounds), Saratov, 2000, p. 113.
9. Koz,minykh, V.O., Igidov, N.M., Koz,minykh, E.N.,
and Berezina, E.S., Abstracts of Papers, I Mezhdu-
narodn. konf. Khimiya i biologicheskaya aktivnost,
sinteticheskikh i prirodnykh soedinenii (1st Int. Conf.
on Chemistry and Biological Activity Synthetic and
Natural Compounds), Moscow: Iridium-press, 2001.
10. Saloutin, V.I., Perevalov, S.G., and Chupakhin, O.N.,
Zh. Org. Khim., 2000, vol. 36, p. 727.
23. Perevalov, S.G., Burgart, Ya.V., Saloutin, V.I., and
Chupakhin, O.N., Usp. Khim., 2001, vol. 70,
p. 1039.
24. Iwanami, Y., Seki, T., and Inagaki, T., Bull. Chem.
Soc. Jap., 1971, vol. 44, p. 1316; Ref. Zh. Khimiya,
1971, no. 23, 23 Zh446.
25. Igidov, N.M., Koz,minykh, E.N., Sof,ina, O.A.,
Shironina, T.M., and Koz,minykh, V.O., Khim.
Geterorsikl. Soed., 1999, p. 1466.
11. Mashevskaya, I.V., Kol,tsova, S.V., and Masli-
vets, A.N., Khim. Geterotsikl. Soed., 2001, p. 705.
12. Sof,ina, O.A., Koz,minykh, V.O., Igidov, N.M.,
Trapeznikova, N.N., and Koz,minykh, E.N.,
Abstracts of Papers, Yubileinaya mezhvuzovskaya
nauchn.-prakt. konf. Aktual, nye problemy farma-
tsevticheskoi nauki i obrazovaniya: itogi i perspekti-
vy (Interuniversity Scientific and Practical Jubiley
Conference on Urgent Problems of Pharmaceutical
Science: Results and Prospects), Perm: Izd. Perm.
Gos. Farm. Akad., 2000, p. 73.
26. Koz,minykh, V.O., Igidov, N.M., Koz,minykh, E.N.,
Berezina, E.S., and Kolotova, N.V., Abstracts of
Papers, Yubileinaya mezhvuzovskoi nauchn.-prakt.
konf. Aktual,nye problemy farmatsevticheskoi nauki
i obrazovaniya: itogi i perspektivy (Interuniversity
Scientific and Practical Jubiley Conference on Urgent
Problems of Pharmaceutical Science: Results and
Prospects), Perm,: Izd. Perm. Gos. Farm. Akad.,
2000, p. 52.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 6 2003