Diaryl-substituted polyethers with acetoacet-anilide fragment in the synthesis of dihydro-pyrimidine-containing podands

Article abstract of DOI:10.1007/s10593-014-1555-7

The interaction of ortho-aminoaryl polyethers, derivatives of mono-, di-, and triethylene glycol, with acetyl ketene, generated from 2,2,6-trimethyl-4H-1,3-dioxin-4-one produced acetoacetanilide- containing podands. 2,2,6-Trimethyl-4H-1,3-dioxin-4-one reacted with aminoaryl-substituted podands containing a short polyether chain (1-2 atoms) in toluene medium without catalyst. Acetoacetanilide- containing podands with longer polyether chains could be obtained by using triethylamine or acetic acid as catalyst. Acetoacetanilide-containing podands were used in the Biginelli reaction as CH-active components.

Full text of DOI:10.1007/s10593-014-1555-7

Chemistry of Heterocyclic Compounds, Vol. 50, No. 7, October, 2014 (Russian Original Vol. 50, No. 7, July, 2014)
DIARYL-SUBSTITUTED POLYETHERS WITH ACETOACET-
ANILIDE FRAGMENT IN THE SYNTHESIS OF DIHYDRO-
PYRIMIDINE-CONTAINING PODANDS*
1,2
2
1,2
1**
E. S. Radionova , Yu. A. Titova , M. L. Isenov , O. V. Fedorova ,
G. L. Rusinov1,2, and V. N. Charushin1,2
The interaction of ortho-aminoaryl polyethers, derivatives of mono-, di-, and triethylene glycol, with
acetyl ketene, generated from 2,2,6-trimethyl-4H-1,3-dioxin-4-one produced acetoacetanilide-
containing podands. 2,2,6-Trimethyl-4H-1,3-dioxin-4-one reacted with aminoaryl-substituted podands
containing a short polyether chain (1-2 atoms) in toluene medium without catalyst. Acetoacetanilide-
containing podands with longer polyether chains could be obtained by using triethylamine or acetic
acid as catalyst. Acetoacetanilide-containing podands were used in the Biginelli reaction as СН-active
components.
Keywords: acetoacetanilide-containing podands, acetyl ketene, aminoaryl-substituted podands,
dihydropyrimidine-containing podands, Biginelli reaction, ultrasonication.
Dihydropyrimidine-containing podands are of interest to researchers as objects of supramolecular
chemistry, as well as potential physiologically active compounds [1]. The simplest and most promising method
for the synthesis of these compounds is the formation of dihydropyrimidine heterocycle on a polyether matrix
by the Biginelli reaction. We have previously involved formyl- or ureide-containing polyethers in the Biginelli
reaction and obtained the respective podands with 3,4-dihydropyrimidin-2-(1Н)-one fragments [2].
In the current work, we used acetoacetylation of aminoaryl-substituted podands in order to synthesize
acetoacetanilide-containing podands, which were used as CH-active reagents in the multicomponent Biginelli
reaction.
The starting acetoacetanilides were obtained by using a cyclic analog of acetoacetic ester, namely,
2,2,6-trimethyl-4H-1,3-dioxin-4-one (1), in the role of acetoacetylating agent, which is known to react readily
with aliphatic and aromatic alcohols, thiols, and amines [3]. Aromatic amines react with acetyl ketene (obtained
by transformation of diketene or 2,2,6-trimethyl-4H-1,3-dioxin-4-one (1)), giving substituted acetoacetanilides [4].
_______
*Dedicated to Academician O. N. Chupakhin on the occasion of his 80th birthday.
**To whom correspondence should be addressed, e-mail: sintonin@mail.ru.
1Ural Federal University named after the First President of Russia B. N. Yeltsin, 19 Mira St., Yekaterinburg
620002, Russia.
2I. Ya. Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, 22 S. Kovalevskoi
St. / 20 Akademicheskaya St., Yekaterinburg 620990, Russia; e-mail: fedorova@ios.uran.ru.
_________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1083-1089, July, 2014. Original
article submitted April 30, 2014.
998
0009-3122/14/5007-0998©2014 Springer Science+Business Media New York

The reaction rate here depends on the basicity of amine. This reaction generally can be performed without
catalyst, but sometimes the presence of a basic or acidic catalyst is required.
We investigated the acetoacetylation reaction of a simple model aromatic amine, 2-methoxyaniline (2),
resulting in compound 4, the methoxy group of which has electronic properties similar to the oxyethylene
fragment of podands. Henning [5] described the synthesis of compound 4 by heating the aniline 2 with diketene
at 70°С in a 5:6 mixture of acetic and formic acids, but the yield was not indicated.
MeO
MeO
А. , 21 h, toluene;
O
H2N
O
N
HN
B. Ultrasound, 45 min
2
O
Me
O
+
4
AcOH 70°C
HCO2H 20 h
Me
Me
OMe
–Me2CO
O
MeO
3
O
O
HN
Me
Me
O
1
Me
Me
O
4
We found that the target amide 4 was formed by heating compounds 1 and 2 in toluene, but the
1Н NMR spectra of reaction mixture showed also the formation of pyridone by-product 3 [6], possibly as a
result of condensation between one molecule of compound 4, the aniline 2, and acetyl ketene. The ratio of
products 3 and 4 was 1:1 at the reaction temperature of 110°С. The mixture of products 3 and 4 was also formed
during ultrasonication, but the ratio was 2:1. The structure of compound 3 [6], which was obtained in 13% yield
upon refluxing in toluene, was confirmed by X-ray structural analysis (Fig. 1). Performing the reaction in a
mixture of acetic and formic acids allowed to obtain the acetoacetanilide 4 in 50% yield, while the formation of
compound 3 was not observed.
The interaction of dioxinone 1 with aminoaryl-substituted podands 5-7 having different lengths of the
oxyethylene fragment [7] produced the acetoacetanilide-containing podands 8-10.
(
)
n
O
O
O
(
)
n
1, toluene
90°C, 25 h
Et3N
(for 10)
O
O
O
NH
HN
O
O
NH2
H2N
5–7
O
O
Me
Me
5, 8 n = 0; 6, 9 n = 1; 7, 10 n = 2
8–10
Under the conditions optimal for the model compound 2 (AcOH, HCOOH, 70°С), the podands 5-7
reacted with compound 1, but the yields of target compounds 8-10 did not exceed 5-7% according to 1H NMR
spectral data. The podands 8 and 9 were synthesized without catalyst by heating the amino compounds 5, 6 with
reagent 1 in toluene at 90°С. The aminoaryl-substituted podand 7 did not react with the dioxinone 1 under these
conditions, but the target podand 10 was readily formed after adding a catalytic amount of acetic acid, or,
preferably, triethylamine. At the same time, the formation of condensation products analogous to compound 3 was
not observed. Based on the obvious influence of oxyethylene fragment on the conditions and outcome of
999

Fig. 1. The molecular structure of compound 3 with atoms represented by thermal vibration ellipsoids of 50%
probability.
the studied reaction, it can be assumed that the acetoacetanilide groups in podands 8-10 did not participate in the
further self-condensation reaction due to the formation of strong intramolecular C=O···HN hydrogen bonds.
1
The Н NMR spectra of acetoacetanilide-containing podands 9 contained aromatic and oxyethylene
fragment proton signals that were shifted downfield compared to the starting aminoaryl-substituted podand 6.
The formation of podand 9 was confirmed by the appearance of characteristic amide NH group signal at
9.44 ppm and two multiplets at 3.88-3.90 and 4.18-4.20 ppm, corresponding to the oxyethylene fragment.
Analogous changes were also observed in the spectra of podands 8, 10. The structure of compound 8 was
unequivocally confirmed by X-ray structural analysis (Fig. 2).
As the next step, we performed the multicomponent Biginelli reaction using the acetoacetanilide-
containing podands 8, 9 as the CH-active components.
(
)
n
8, 9
+
PhCHO
+
O
O
O
THF, PPA
, 26 h
EtOH
HCl

NH
HN
Me
HN
Me
NH
CO(NH2)2
O
O
O
Ph
Ph
N
H
N
H
HN
NH
Ph
O
O
+ 5, 6
11 (n = 0)
12 (n = 1)
Me
OEt
13
It was established that products 11, 12 were not formed under the classical Biginelli reaction conditions
(EtOH, HCl, reflux) because of hydrolysis of podands 8, 9 leading to the amino compounds 5, 6, respectively.
This was evidenced by the presence of free NH2 group signals at 4.66 ppm in the 1H NMR spectrum of reaction
mixture obtained during the synthesis of podand 12, as well as the aromatic (6.48-6.81 ppm) and oxyethylene
(4.07, 3.82 ppm) proton signals of aminopodand 6 – the decomposition product obtained from compound 9.
Signals corresponding to the dihydropyrimidinone 13 [8] were also observed: 4-СН proton doublet at 5.14 ppm,
ethoxy group proton signals at 1.09 ppm (t) and 3.98 ppm (q), as well as signals of two NН groups at 7.74 ppm
(d) and 9.19 ppm (br. s). This indicated that the eliminated acetoacetyl fragment was converted to acetoacetic
ester in ethyl alcohol medium, as well that it further condensed with aldehyde and urea.
1000

Fig. 2. The molecular structure of compound 8 with atoms represented by thermal vibration ellipsoids of 50%
probability.
The multicomponent Biginelli reaction involving acetoacetanilides is known to proceed better in THF
[9], while polyphosphoric acid (PPA) and its esters are the most effective catalysts.
Indeed, acetoacetanilide-containing podands 8 and 9 gave the corresponding dihydropyrimidines 11 and
12 in 8-10% yields upon interaction with benzaldehyde and urea in THF in the presence of PPA. The 1Н NMR
spectrum of podand 11 showed a duplication of adjacent CH and NH proton signals in the dihydropyrimidine
ring. This was apparently linked to the formation of two diastereomers, which is characteristic for symmetrical
podands with two chiral centers [10].
Thus, we have developed a method for the synthesis of acetoacetanilide-containing podands with
different oxyethylene fragment lengths. Acetoacetanilide-containing podands were shown to participate in the
Biginelli reaction with benzaldehyde and urea in the presence of polyphosphoric acid as catalyst, forming
dihydropyrimidine-containing podands.
REFERENCES
IR spectra were recorded on a Perkin Elmer Spectrum One FTIR spectrometer in 4000-400 cm-1 range with
1
diffuse reflectance accessory. Н NMR spectra were acquired on a Bruker DRX 400 spectrometer (400 MHz) in
DMSO-d6, with TMS as internal standard. Elemental analysis (С, H, N) was performed on a Carlo Erba 1108
analyzer. Melting points were determined on a combined Boetius hot stage apparatus and were not corrected. The
reaction progress and purity of the synthesized compounds were controlled by TLC on Sorbfil plates, visualization
with iodine vapor.
The reagents used in this work were 2-methoxyaniline (2) (98%), 2,2,6-trimethyl-4H-1,3-dioxin-4-one
(1) (94%), and PPA (84%) from Lancaster, benzaldehyde (98%) and urea (98%) from Acros Organics, and
chemically pure solvents from Vekton. Aminoaryl-substituted podands 5-7 were obtained by a published
method [7].
Reaction of 2,2,6-Trimethyl-4H-1,3-dioxin-4-one (1) and 2-Methoxyaniline (2) in Toluene. А. A
solution of 2,2,6-trimethyl-4H-1,3-dioxin-4-one (1) (0.57 g, 4 mmol) and 2-methoxyaniline (2) (0.50 g, 4 mmol)
in toluene (10 ml) was refluxed with stirring for 21 h. At the end of the reaction (control by TLC, eluent 5:1:1
EtOAc–hexane–CHCl3), a 1:1 mixture of N,1-bis(2-methoxyphenyl)-2,6-dimethyl-4-oxo-1,4-dihydropyridine-
3-carboxamide (3) and N-(2-methoxyphenyl)-3-oxobutanamide (4) was obtained. The oily residue obtained
after removal of toluene by distillation was washed with Et2O until the formation of a solid powder, which was
filtered off and recrystallized from 1,4-dioxane, yielding compound 3. Yield 0.19 g (13%). The ether filtrate
1001

obtained after crystallization of compound 3 was evaporated, the precipitate was recrystallized from EtOH–H2O
3:2, giving compound 4. Yield 0.11 g (13%).
B. A solution of 2,2,6-trimethyl-4H-1,3-dioxin-4-one (1) (0.57 g, 4 mmol) and 2-methoxyaniline (2)
(0.50 g, 4 mmol) in toluene (9 ml) was sonicated with submerged ultrasonic horn for 3×15 min. After the
completion of reaction (control by TLC, eluent 5:1:1 EtOAc–hexane–CHCl3), a 2:1 mixture of compounds 3
and 4 was obtained. Toluene was removed by distillation, the residue was triturated with Et2O, crystals of
compound 3 were filtered off, dried, and recrystallized from a 1:1 mixture of 1,4-dioxane and Н2О. Yield 0.29 g
(19%). The ether filtrate obtained after crystallization of compound 3 was evaporated, the residue was
recrystallized from a 3:2 EtOH–H2O mixture, yielding compound 4. Yield 0.08 g (10%). Compounds 3 and 4
obtained by ultrasonication or refluxing the reaction mixture had identical physicochemical characteristics.
N,1-Bis(2-methoxyphenyl)-2,6-dimethyl-4-oxo-1,4-dihydropyridine-3-carboxamide (3). Light-gray
crystals, mp 241-242°С (mp 237-240°С [6]). IR spectrum, ν, cm-1: 758, 1460, 1597 (Ar); 1019, 1249 (νs, νas, –О–СAr);
1120, 1164 (νs, νas, –О–СAlk); 1344, 1460 (–CO–СAlk); 1278 (C–N); 1527, 1666 (–СO–N); 2937, 2835
(СAlk–Н). 1H NMR spectrum, δ, ppm (J, Hz): 1.85 (3H, s, 6-CH3); 2.32 (3H, s, 2-CH3); 3.84 (3H, s, ОCH3); 3.86
(3H, s, ОCH3); 6.48 (1H, s, H-5); 6.88-6.92 (1H, m, H Ar); 7.03-7.04 (2H, m, H Ar); 7.15-7.19 (1H, m, H Ar);
7.31-7.33 (1H, m, H Ar); 7.42-7.44 (1H, m, H Ar); 7.56-7.60 (1H, m, H Ar); 8.35 (1H, d, 2J = 7.7, H Ar); 12.52
(1H, s, NH). Found, %: С 69.99; Н 5.62; N 7.24. C22H22N2O4. Calculated, %: С 69.83; Н 5.86; N 7.40.
N-(2-Methoxyphenyl)-3-oxobutanamide (4). A mixture of 2,2,6-trimethyl-4H-1,3-dioxin-4-one (1)
(1.73 g, 12 mmol), 2-methoxyaniline (2) (1.00 g, 8 mmol), НСООН (0.03 g, 0.65 mmol), and АсОН (10 ml) was
stirred for 20 h at 70°С. After the completion of reaction (control by TLC, eluent 5:1:1 EtOAc–hexane–CHCl3),
the solvent was removed by evaporation. The obtained oily product was washed with Et2O until the formation
of a solid powder and recrystallized from a 3:2 mixture of EtOH–H2O. Yield 0.84 g (50%), light-brown crystals,
mp 77-78°С. IR spectrum, ν, cm-1: 759, 1486, 1596 (Ar); 1021, 1251 (νs, νas, –О–СAr); 1119, 1161 (νs, νas,
–О–СAlk); 1358, 1458 (–CO–СAlk); 1289 (C–N); 3280 (N–H); 1708 (С=О); 1529, 1675 (–СO–N); 2933, 2842
1
(СAlk–Н); 3064 (СAr–Н). H NMR spectrum, δ, ppm (J, Hz): 2.18 (3H, s, CH3); 3.66 (2H, s, CH2); 3.83 (3H, s,
2
ОCH3); 6.87-6.92 (1H, m, H Ar); 7.03-7.09 (2H, m, H Ar); 8.01 (1H, d, J = 7.8, H Ar); 9.46 (1H, s, NH).
Found, %: С 63.73; Н 6.69; N 6.55. C11H13NO3. Calculated, %: С 63.76; Н 6.32; N 6.76.
Synthesis of Acetoacetanilide-containing Podands 8, 9 (General Method). A mixture of 2,2,6-tri-
methyl-4H-1,3-dioxin-4-one (1) (1.0 g, 7.5 mmol), aminoaryl-substituted podands 5, 6, and toluene (10 ml) was
stirred for 25 h at 90°С. After the completion of reaction (control by TLC, eluent 5:1:1 EtOAc–hexane–CHCl3),
toluene was removed by distillation. The obtained oil was washed with Et2O and MeOH until the formation of a
solid powder, which was further purified by recrystallization from EtOH.
1,2-Bis[2-(N-acetoacetamide)phenoxy]ethane (8). Yield 0.42 g (41%), yellow crystals, mp 138-140°С.
IR spectrum, ν, cm-1: 750, 1486, 1604 (Ar); 1067, 1251 (νs, νas, –О–СAr); 1118, 1158 (νs, νas, –О–СAlk); 1364,
1446 (–CO–СAlk); 1286 (C–N); 3335 (N–H); 1715 (С=О); 1538, 1658 (–СO–N); 2938, 2891 (СAlk–Н); 3065
1
(СAr–Н). H NMR spectrum, δ, ppm (J, Hz): 2.14 (6H, s, 2CH3); 3.59 (4H, s, 2СОCH2СО); 4.42 (4H, s,
2
ОCH2СН2О); 6.94-6.95 (2H, m, H Ar); 7.07-7.15 (4H, m, H Ar); 7.96 (2H, d, J = 8.0, H Ar); 9.40 (2H, s,
2NH). Found, %: С 64.52; Н 5.82; N 6.77. С22H24N2O6. Calculated, %: С 64.07; Н 5.87; N 6.79.
1,5-Bis[2-(N-acetoacetamide)phenoxy]-3-oxapentane (9). Yield 0.58 g (51%), colorless crystals,
mp 149-150°С. IR spectrum, ν, cm-1: 748, 1494, 1598 (Ar); 1058, 1243 (νs, νas, –О–СAr); 1116, 1163 (νs, νas,
–О–СAlk); 1361, 1449 (–CO–СAlk); 1281 (C–N); 3269 (N–H); 1715 (С=О); 1547, 1646 (–СO–N); 2931, 2891,
1
(СAlk–Н); 3066 (СAr–Н). H NMR spectrum, δ, ppm (J, Hz): 2.17 (6H, s, 2CH3); 3.63 (4H, s, 2СОCH2СО);
3.88-3.90 (4H, m) and 4.18-4.20 (4H, m, CH2CH2ОCH2CH2); 6.89-6.93 (2H, m, H Ar); 7.05-7.08 (4H, m,
2
H Ar); 7.97 (2H, d, J = 7.8, H Ar); 9.44 (2H, s, 2NH). Found, %: С 63.24; Н 6.38; N 6.08. С24H28N2O7.
Calculated, %: С 63.15; Н 6.18; N 6.14.
1,8-Bis[2-(N-acetoacetamide)phenoxy]-3,6-dioxaoctane (10). A mixture of aminoaryl-substituted
podand 7 (0.83 g, 2.5 mmol), 2,2,6-trimethyl-4H-1,3-dioxin-4-one (1) (1.0 g, 7.5 mmol), triethylamine (0.05 g,
0.5 mmol), and toluene (10 ml) was stirred and heated for 25 h at 90°С. After the completion of reaction
1002

(control by TLC, eluent 5:4:1 EtOAc–hexane–CHCl3), toluene was removed by distillation. The obtained oil
was purified by sequential washing with diethyl ether and methanol, dried in air. Yield 0.61 (49%), brown oil.
IR spectrum, ν, cm-1: 750, 1487, 1600 (Ar); 1051, 1255 (νs, νas, –О–СAr); 1117, 1160 (νs, νas, –О–СAlk); 1359,
1451 (–CO–СAlk); 1289 (C–N); 3283 (N–H); 1713 (С=О); 1533, 1680 (–СO–N); 2873 (СAlk–Н); 3065
1
(СAr–Н). H NMR spectrum, δ, ppm (J, Hz): 2.19 (6H, s, 2CH3); 3.62 (4H, s, 2СОCH2СО); 3.63-3.64 (4H,
br. s), 3.78-3.80 (4H, m) and 4.13-4.15 (4H, m, (ОCH2CH2)3); 6.89-6.92 (2H, m, H Ar); 7.02-7.06 (4H, m,
2
H Ar); 7.97 (2H, d, J = 7.8, H Ar); 9.41 (2H, s, 2NH). Found, %: С 62.79; Н 6.49; N 5.15. С26H32N2O8.
Calculated, %: С 62.39; Н 6.44; N 5.60.
Synthesis of Dihydropyrimidine-containing Podands 11, 12 (General Method). A mixture of aceto-
acetanilide containing podands 8, 9 (0.7 mmol), benzaldehyde (0.15 g, 1.4 mmol), urea (0.13 g, 2.1 mmol), PPA
(0.14 g, 1.4 mmol), and THF (10 ml) was refluxed for 26 h. The precipitate was filtered off and washed multiple
times with hot water to remove urea. The product was purified by sequential washing with hot МеОН, acetone,
and Et2O.
1,2-Bis[2-(4-methyl-2-oxo-6-phenyl-1,2,3,6-tetrahydropyrimidine-5-carboxamide)phenoxy]ethane
(11). Yield 0.04 g (8%), beige powder, mp 287-289°С. IR spectrum, ν, cm-1: 747, 1599 (Ar); 1049, 1241 (νs, νas,
–О–СAr); 1120 (νs, νas, –О–СAlk); 1445 (–С=С–СAlk); 1657 (–С=С–); 1333 (–CO–СAlk); 1287 (C–N); 3244
1
(N–H); 1696 (С=О); 1517, 1657 (–СO–N); 2943 (СAlk–Н); 3093 (СAr–Н). H NMR spectrum, δ, ppm (J, Hz):
2.07 (6H, s, 2CH3); 4.19 (4H, s, ОCH2CH2О); 5.24 (2H, d, 2J = 3.0, 6,6'-CH); 6.88-6.92 (2H, m, H Ar); 7.0-7.07
(4H, m, H Ar); 7.15-7.18 (2H, m, H Ar); 7.25-7.27 (8H, m, H Ar); 7.52-7.54 (2H, m, 2NH); 7.83-7.84 (2H, m,
H Ar); 8.29 (2H, s, 2NH); 8.75 (2H, s, 2NH). Found, %: С 67.84; Н 5.77; N 11.97. С38H36N6O6. Calculated, %:
С 67.84; Н 5.39; N 12.49.
1,5-Bis[2-(4-methyl-2-oxo-6-phenyl-1,2,3,6-tetrahydropyrimidine-5-carboxamide)phenoxy]-3-oxa-
pentane (12). Yield 0.05 g (10%), white powder, mp 268-270°С. IR spectrum, ν, cm-1: 741, 1598 (Ar); 1049,
1243 (νs, νas, –О–СAr); 1138 (νs, νas, –О–СAlk); 1449 (–С=С–СAlk); 1668 (–С=С–); 1320 (–CO–СAlk); 1262
1
(C–N); 3280 (N–H); 1708 (С=О); 1521, 1633 (–СO–N); 2937 (СAlk–Н); 3118 (СAr–Н). H NMR spectrum, δ,
ppm (J, Hz): 2.20 (6H, s, 2CH3); 3.69-3.71 (4H, m) and 4.05-4.09 (4H, m, CH2CH2ОCH2CH2); 5.27-5.28 (2H,
m, 6,6'-CH); 6.84-6.89 (2H, m, H Ar); 6.99-7.01 (4H, m, H Ar); 7.22-7.26 (2H, m, H Ar); 7.32-7.33 (8H, m,
H Ar); 7.66 (2H, s, 2NH); 7.84-7.87 (2H, m, H Ar); 8.33 (2H, s, 2NH); 8.84 (2H, s, 2NH). Found, %: С 66.21;
Н 5.45; N 11.32. С40H40N6O7·0.5H2O. Calculated, %: С 66.19; Н 5.69; N 11.58.
X-ray structural investigation of compounds 3 and 8 was performed on an Xcalibur 3 automated
four-circle X-ray diffractometer according to standard procedure (MoKα-radiation, graphite monochromator,
295(2) K, ω-scanning). The analyzed crystal fragment of compound 3 had dimensions of 0.25×0.20×0.15 mm,
while the crystal fragment of compound 8 – 0.35×0.30×0.25 mm. The crystals of compound 3 (C22H22N2O4,
M 378.42) were of rhombic syngony; a 25.399(2), b 8.6693(11), c 17.6612(19) Å; V 3888.8(7) Å3; Z 8; space group
Pca2(1); dcalc 1.293 g/cm3; μ(MoKα) 0.090 mm-1; F(000) 1600. A total of 17944 reflections were collected, 6932
independent (of those 2295 significant, Rint 0.0564). Crystals of compound 8 (C22H24N2O6, M 412.43) had triclinic
syngony_; a 8.608(2), b 10.649(3), c 12.283(7) Å; α 77.17(4), β 74.47(3), γ 86.25(2)°; V 1057.7(8) Å3; Z 2; space
group P1; dcalc 1.295 g/cm3; μ(MoKα) 0.095 mm-1; F(000) 436. A total of 8130 reflections were collected, 4083
independent (of those 1229 significant, Rint 0.0482). The structures were solved and refined by using SHELX97
software package [11]. All non-hydrogen atoms were refined in anisotropic approximation; hydrogen atoms except
those of NH groups were placed in geometrically calculated positions and included in the refinement by using "rider"
model with dependent isotropic thermal parameters. The NH group protons were refined independently in isotropic
approximation. The final refinement results for structure 3: R1 0.0441, wR2 0.0597 (for reflections with I > 2σ(I)),
R1 0.1538, wR2 0.0643 (for all reflections) at S 1.000. The final refinement results for structure 8: R1 0.0451,
wR2 0.0590 (for reflections with I > 2σ(I)), R1 0.1839, wR2 0.0635 (for all reflections) at S 0.935.
The X-ray structural analysis data were deposited at the Cambridge Crystallographic Data Center
(deposits CCDC 1007517 (compound 3) and CCDC 1007518 (compound 8)).
1003

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1.
E. S. Pereyaslavskaya, V. A. Potemkin, E. V. Bartashevich, M. A. Grishina, G. L. Rusinov,
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