(6-Benzyloxy-2,5,7,8-tetramethylchroman-2-yl)acetaldehyde conjugates with 20-hydroxyecdysone, stachysterone B, and their 20,22-acetonides

Article abstract of DOI:10.1134/S1070428010080075

Conjugates consisting of ecdysteroid and a-tocopherol analog fragments were synthesized for the first time from 20-hydroxyecdysone and (6-benzyloxy-2,5,7, 8-tetramethylchroman-2-yl)acetaldehyde. Pleiades Publishing, Ltd., 2010.

Full text of DOI:10.1134/S1070428010080075

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 8, pp. 1157–1161. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © R.G. Savchenko, Ya.R. Urazaeva, A.Yu. Spivak, V.N. Odinokov, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46,
No. 8, pp. 1158–1161.
(6-Benzyloxy-2,5,7,8-tetramethylchroman-2-yl)acetaldehyde
Conjugates with 20-Hydroxyecdysone, Stachysterone B,
and Their 20,22-Acetonides
R. G. Savchenko, Ya. R. Urazaeva, A. Yu. Spivak, and V. N. Odinokov
Institute of Petroleum Chemistry and Catalysis, Russian Academy of Sciences,
pr. Oktyabrya 141, Ufa, 450075 Bashkortostan,
e-mail: ink@anrb.ru
Received July 17, 2009
Abstract—Conjugates consisting of ecdysteroid and α-tocopherol analog fragments were synthesized for the
first time from 20-hydroxyecdysone and (6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)acetaldehyde.
DOI: 10.1134/S1070428010080075
Ecdysteroids (insect ecdysis, metamorphosis, and
diapause hormones) are present not only in insect
organisms, but also (in considerably higher concentra-
tions) in plants from which these unique polyhy-
droxylated sterols were isolated. The properties and
some chemical transformations of ecdysteroids were
studied [1, 2]. It was found that ecdysteroids are non-
toxic for warm-blooded animals. Versatile physiologi-
cal effect of ecdysteroids on humans and animals was
revealed: they were found to control mineral, carbo-
hydrate, lipid, and protein exchange, normalize sugar
and cholesterol concentration in blood, stimulate
hemopoietic activity, and exert immunomodulatory
effect [3]. The diversity of physiological action of
ecdysteroids is determined to some extent by their
antioxidant properties, for many diseases are related to
oxidative stress [4].
We believed that a promising way of enhancing
pharmacological effect of ecdysteroids may be con-
jugation with natural phenolic antioxidants such as
α-tocopherol and its analogs. For this purpose, we ex-
amined reactions of 20-hydroxyecdysone (I) and its
2,3- and 20,22-acetonides II and III with (6-benzyl-
oxy-2,5,7,8-tetramethylchroman-2-yl)acetaldehyde
(IV). The reaction of ecdysteroid I with 2 equiv of
aldehyde IV, catalyzed by phosphomolybdic acid
(PMA), gave 62% of the corresponding bis-adduct V
(Scheme 1). This reaction occurred at a higher rate in
the presence of p-toluenesulfonic acid as catalyst, but
the yield of bis-acetal V did not change. Bis-adduct V
was also formed in the reaction of 20-hydroxyecdy-
sone 2,3-acetonide (II) with an equimolar amount of
aldehyde IV in the presence of TsOH or PMA, but the
yield was lower (35%). Under analogous conditions,
from 20,22-acetonide III we obtained 60% of 2,3-ad-
duct VI. Presumably, the formation of bis-adduct V
from 2,3-acetonide II is favored due to known lability
of compound II in acid medium [1].
Apart from 20-hydroxyecdysone conjugates V and
VI, from the reaction mixtures we isolated the corre-
sponding 14,15-anhydro derivatives VII and VIII in
26 and 20% yield, respectively. Compounds VII and
VIII can be regarded as analogous stachysterone B
conjugates. 20-Hydroxyecdysone conjugates V and VI
were subjected to debenzylation by hydrogenation over
Pd/C in ethanol solution. As a result, the corresponding
hydroxy derivatives IX and X were smoothly formed.
The MALDI-TOF mass spectrum of bis-adduct IX
1
13
contained [M + H]+
ion peak. In the H and C NMR
spectra of compounds V–X we observed signals from
all protons iand carbon nuclei in the ecdysteroid and
chroman fragments, in keeping with the assumed struc-
ture of their molecules.
Monoadduct VI displayed in the 13C NMR spec-
trum (in the region typical of acetal carbon atoms)
signals from quaternary (δC 106.97 ppm) and tertiary
(δC 101.97 ppm) carbon atoms in the 20,22-O-iso-
propylidene (cf. [5]) and ethylidenedioxy groups (cf.
[6]), respectively. The 13C NMR spectrum of bis-ad-
duct V contained three signals from carbon atoms in
the ethylidenedioxy groups at δC 101.99, 101.41, and
101.63 ppm with an intensity ratio of 2:1:1. Obvi-
1157

SAVCHENKO et al.
1158
Scheme 1.
OR4
OR3
Me
Me
Ph
Me
Me
Me
O
Me
H
CHO
+
Me
OH
R1O
R2O
Me
O
H
O
OH
Me
I–III
IV
RO
OR4
22
OR3
Me
6'
21Me
18Me
5'
4a'
4'
7'
8'
Me
24
20
17
26
Me
25
23
12
19Me
8a'
13
14
11
9
3'
27
Me
PMA or TsOH
16
2'
Me
OH
O
15
O
1
4
2'''
10
5
2
3
8
Me
H
OH
1'''
7
6
O
H
O
V, VI, IX, X
RO
OR4
OR3
Me
Me
Me
Me
+
Me
OH
Me
Me
H
Me
O
Me
O
H
O
O
VII, VIII
1''''
1''''
H
H
2''''
2''''
(S)
(R)
O
O
O
O
21
Me
21
Me
H2, Pd/C, EtOH
(R)
(R)
(R)
(R)
VI, VI
IX, X
24
24
22
22
20
20
26
26
25
25
17
17
23
23
Me
Me
H
H
27
Me
27
Me
16
16
OH
OH
I, III, R1 = R2 = H; I, II, R3 = R4 = H; II, R1R2 = Me2C; III, VI, VIII, X, R3R4 = Me2C;
Me
4''
5''
RO
Me
4a''
6''
7''
3''
2''
V, VII, IX, R3R4 =
; V–VIII, R = PhCH2; IX, X, R = H.
2''''
8a''
Me1''''
O
8''
Me
ously, the two latter signals correspond to the 20,22-O-
(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)ethyli-
dene fragment.
The formation of 1,3-dioxolane derivatives, i.e.,
cyclic 2,3- and 20,22-acetals, involves appearance of
two new asymmetric centers, the C2″′ and C2″″ atoms in
V. Among these, only the latter (C2″″) gives two signals
as a result of formation of (S,R,R)- and (R,R,R)-dia-
stereoisomers. Obviously, the C2″″ signal is doubled
due to the presence of strongly different substituents
on C20 and C22 in the 1,3-dioxolane ring of 20,22-ace-
tal. On the other hand, the substituents on C2 and C3 in
the 1,3-dioxolane ring of the 2,3-acetal moiety differ
only slightly, and the C2″′ chiral acetal carbon atom
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

(6-BENZYLOXY-2,5,7,8-TETRAMETHYLCHROMAN-2-YL)ACETALDEHYDE
1159
gives only one peak in the 13C NMR spectrum. Protons
(3H, C26H3), 1.28 s (3H, C27H3), 1.37 s (6H, 2′-CH3,
2″-CH3); 2.11 s, 2.18 s, and 2.24 s (6H each, CH3);
2.63 m (4H, 4′-H, 4″-H), 3.62 m (1H, 22-H), 4.10 m
(1H, 2-H), 4.14 m (1H, 3-H), 4.71 s (4H, OCH2Ph),
5.18 br.s (1H, 2″′-H), 5.24 br.s (1H, 2″′-H), 5.85 s (1H,
7-H), 7.35–7.50 m (10H, Harom). 13C NMR spectrum,
δC, ppm: 11.92, 12.01, and 12.89 (6C, Me); 17.00
(C18), 20.56 (C19), 20.56 (C4′, C4″), 21.50 (C11), 23.04
(C16), 23.61 (C21), 24.80 (2′-Me), 24.97 (2″-Me), 26.68
(C23), 29.47 (C26, C27), 30.86 (C15), 30.94 (C4), 31.74
(C3′), 31.85 (C3″) 34.00 (C12), 34.71 (C9), 37.82 (C1),
38.40 (C10), 41.41 (C24), 45.53 (C13), 47.36 (C5), 49.74
(C1″′, C17), 50.83 (C1″″), 70.48 (C25), 73.36 (C2′ , C2″),
74.75 (OCH2Ph), 76.75 (C3), 77.07 (C2), 83.55 (C20),
83.85 (C22), 84.86 (C14), 101.41 and 101.63 (C2″″),
101.99 (C2′′′), 117.41 (C8a′), 117.49 (C8a″), 121.43 (C7),
123.04 (C8′, C8″), 126.06 (C7′, C7″), 127.74, 127.76 and
128.47 (Ph), 128.06 (C5′, C5″), 137.97 (OCH2C), 147.48
(C4a′), 147.60 (C4a″), 148.39 (C6′, C6″), 163.23 (C8),
202.62 (C6). Found, %: C 75.95; H 7.99. C71H92O11.
Calculated, %: C 76.04; H 8.27.
Compound VII. Yield 0.12 g (26%), mp 124–
125°C, [α]D20 = –3.4° (c = 1.37, CHCl3). 1H NMR spec-
trum, δ, ppm: 0.80 s (3H, C18H3), 0.97 s (3H, C19H3),
1.14 s (3H, C21H3), 1.26 s (6H, C26H3, C27H3), 1.35 s
(6H, 2′-CH3, 2″-CH3); 2.09 s, 2.18 s, and 2.22 s (6H
each, CH3); 2.62 m (4H, 4′-H, 4″-H), 3.66 m (1H, C22),
4.12 m (1H, 2-H), 4.30 m (1H, 3-H), 4.69 s (4H,
OCH2Ph), 5.12 br.s (1H, 2″″-H), 5.23 br.s. (1H, 2′′′-H),
5.98 br.s (1H, 15-H), 6.10 s (1H, 7-H), 7.20–7.51 m
(10H, Harom).
b. A solution of 0.28 g (0.83 mmol) of aldehyde IV
in 3 ml of ethyl acetate was added to a solution of
0.20 g (0.42 mmol) of compound I in 3 ml of ethyl
acetate, 0.02 g of phosphomolybdic acid was added,
and the mixture was stirred for 54 h at room tempera-
ture and evaporated. The mixture was then treated as
described above in a to isolate 0.29 g (61%) of com-
pound V and 0.12 g (25%) of VII.
c. A solution of 0.13 g (0.38 mmol) of aldehyde IV
in 3 ml of ethyl acetate was added to a solution of
0.20 g (0.38 mmol) of compound II in 3 ml of ethyl
acetate, 0.02 g of p-toluenesulfonic acid was added,
and the mixture was stirred for 24 h at room tempera-
ture and evaporated. The subsequent procedure was the
same as that described above in a. We isolated 0.13 g
(30%) of compound V and 0.07 g (15%) of VII.
at the C2″′ and C2″″ acetal carbon atoms in V resonated
1
in the H NMR spectrum as broadened singlets (w1/2
=
13 Hz) at δ 5.18 (20,22) and 5.24 ppm (2,3).
13
In the C NMR spectrum of compound VIII, in-
stead of signals at δC ~30.86 (C15) and 84.86 ppm
(C14), we observed signals typical of sp2-hybridized
carbon atoms at δ ~122.98 (C14) and 148.75 ppm (C15).
The 1H NMR spectra of VII and VIII displayed an ad-
ditional signal at δ ~6.0 ppm (15-H) (apart from the
7-H signal at δ ~6.1 ppm). These findings reflected
formation of double C14=C15 bond in stachysterone B
conjugates VII and VIII (cf. [5]).
To conclude, we were the first to synthesize ecdy-
steroid conjugates with α-tocopherol analog at the
ω-aldehyde group of the latter.
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded from
solutions in CDCl3 on a Bruker Avance-400 instrument
at 400.13 and 100.62 MHz, respectively. Signals were
assigned with the use of homo- and heteronuclear
correlation techniques (DEPT-135, COSY, HSQC,
HMBC). The chemical shifts were determined relative
to tetramethylsilane as internal reference. The mass
spectrum of compound IX was obtained on a Bruker
Autoflex III instrument (MALDI TOF, positive ion
detection). The melting points were determined on
a Boetius melting point apparatus. The optical rota-
tions were measured on a Perkin–Elmer-141 polarim-
eter. The purity of the products was checked by TLC
on Silufol plates; spots were developed by treatment
with a solution of vanillin in ethanol acidified with
sulfuric acid.
2,3:20,22-Bis-O-[2-(6-benzyloxy-2,5,7,8-tetra-
methylchroman-2-yl)ethylidene]-20-hydroxyecdy-
sone (V) and 2,3:20,22-bis-O-[2-(6-benzyloxy-
2,5,7,8-tetramethylchroman-2-yl)ethylidene]stachy-
sterone B (VII). a. A solution of 0.28 g (0.83 mmol)
of aldehyde IV in 3 ml of ethyl acetate was added to
a solution of 0.20 g (0.42 mmol) of compound I in
3 ml of ethyl acetate, 0.02 g of p-toluenesulfonic acid
was added, and the mixture was stirred for 24 h at
room temperature and evaporated. The residue was
subjected to column chromatography on silica gel
(20 g) using chloroform as eluent.
Compound V. Yield 0.29 g (62%), Rf 0.56 (CHCl3–
MeOH, 20 :1), mp 128–130°C, [α]D20 = +20.7° (c =
2,3-O-[2-(6-Benzyloxy-2,5,7,8-tetramethylchro-
man-2-yl)ethylidene]-20,22-O-isopropylidene-20-
hydroxyecdysone (VI) and 2,3-O-[2-(6-benzyloxy-
1
2.03, CHCl3). H NMR spectrum, δ, ppm: 0.90 s (3H,
C18H3), 1.00 s (3H, C19H3), 1.17 s (3H, C21H3), 1.27 s
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

SAVCHENKO et al.
1160
2,5,7,8-tetramethylchroman-2-yl)ethylidene]-20,22-
O-isopropylidenestachysterone B (VIII). A solution
of 0.08 g (0.24 mmol) of aldehyde IV in 2 ml of
methylene chloride was added to a solution of 0.24 g
(0.46 mmol) of compound III in 5 ml of methylene
chloride, 0.02 g of phosphomolybdic acid was added,
and the mixture was stirred for 48 h at room tempera-
ture and evaporated. The residue was subjected to
chromatography on silica gel (20 g) using chloroform
as eluent to isolate 0.24 g (60%) of compound VI,
Rf 0.53 (CHCl3–MeOH, 20:1) and 0.08 g (20%) of
VIII, Rf 0.58 (CHCl3–MeOH, 30:1).
(C3), 77.04 (C2), 81.72 (C22), 83.33 (C20), 117.40 (C8′),
122.98 (C14), 128.46 (C15), 101.99 (C2′′′), 117.05 (C8a′),
121.31 (C7), 120.72 (C7′); 126.03, 126.07, and 128.46
(Carom); 128.09 (C5′), 137.00 (OCH2C), 147.45 (C4a′),
148.75 (C6′), 153.86 (C8), 202.10 (C6).
2,3:20,22-Bis-O-[2-(6-hydroxy-2,5,7,8-tetra-
methylchroman-2-yl)ethylidene]-20-hydroxyecdy-
sone (IX). Hydrogen was passed through a suspension
of 0.28 g (0.25 mmol) of compound V and 0.07 g of
10% Pd/C in 5 ml of anhydrous methanol until the
reaction was complete (~3 h, TLC). The catalyst was
filtered off, the filtrate was evaporated, and the residue
was subjected to chromatography on silica gel (15 g)
using chloroform as eluent. Yield 0.23 g (96%),
mp 130–134°C, [α]D20 = +24.5° (c = 1.82, CH2Cl2).
1H NMR spectrum, δ, ppm: 0.71 s (3H, C18H3), 0.97 s
(3H, C19H3), 1.15 s (3H, C21H3), 1.26 s (6H, C26H3,
C27H3), 1.33 s (3H, 2′-CH3), 1.34 s (3H, 2″-CH3);
2.11 s, 2.16 s, and 2.18 s (6H each, CH3); 2.62 s (4H,
4′-H, 4″-H), 3.59 m (1H, 22-H), 4.12 m (1H, 2-H),
4.46 m (1H, 3-H), 5.14 br.s (1H, 2″″-H), 5.21 br.s (1H,
2′′′-H), 5.82 s (1H, 7-H). 13C NMR spectrum, δC, ppm:
11.32, 11.85, and 12.26 (CH3); 16.97 (C18), 20.63
(C19), 20.63 (C4′, C4″), 21.46 (C11), 23.00 (C16), 23.53
(C21), 24.37 (2′-CH3, 24.64 (2″-CH3), 26.65 (C23),
29.43 (C26, C27), 30.82 (C15), 30.92 (C4), 31.65 (C3′),
31.95 (C3″) 33.16 (C12), 34.69 (C9), 37.80 (C1), 38.37
(C10), 41.38 (C24), 45.42 (C13), 47.33 (C5), 49.71 (C17),
50.90 (C1′′′, C1″″), 70.51 (C25), 73.05 (C2′), 73.32 (C2″),
76.73 (C3), 77.05 (C2), 83.59 (C20), 83.83 (C22), 84.80
(C14), 101.44 and 101.66 (C2″″) 102.01 (C2′′′), 117.10
(C8a′, C8a″), 118.71 (C5′, C5″), 121.38 (C8′, C8″, C7),
122.64 (C7′, C7″), 144.81 (C4a′, C4a″), 145.11 (C6′),
163.21 (C8), 203.01 (C6). Mass spectrum: m/z 942.360
[M + H]+. C57H80O11. Calculated: M 941.248.
2,3-O-[2-(6-Hydroxy-2,5,7,8-tetramethylchro-
man-2-yl)ethylidene]-20,22-O-isopropylidene-20-
hydroxyecdysone (X). Hydrogen was passed over
a period of 3 h through a suspension of 0.12 g
(0.14 mmol) of compound VI and 0.03 g of 10% Pd/C
in 5 ml of anhydrous methanol. The catalyst was
filtered off, the filtrate was evaporated, and the residue
was subjected to column chromatography on silica gel
(15 g) using chloroform as eluent. Yield 0.10 g (90%),
mp 150–152°C, [α]D20 = +10.44° (c = 3.76, CHCl3).
1H NMR spectrum, δ, ppm: 0.80 s (3H, C19H3), 0.96 s
(3H, C18H3), 1.17 s (3H, C21H3), 1.24 s (3H, C26H3),
1.25 s (3H, C27H3), 1.33 s [6H, (CH3)2C], 1.42 s (3H,
2′-CH3), 2.10 s and 2.15 s (9H, CH3), 2.62 m (2H,
4′-H), 3.67 m (1H, 22-H), 4.12 m (1H, 2-H), 4.41 m
(1H, 3-H), 5.20 br.s (1H, 2′′′-H), 5.83 s (1H, 7-H).
Compound VI. mp 138–140°C, [α]D20 = +19.3° (c =
1
1.77, CHCl3). H NMR spectrum, δ, ppm: 0.80 s (3H,
C19H3), 0.97 s (3H, C18H3), 1.18 s (3H, C21H3), 1.24 s
(6H, C26H3, C27H3), 1.34 s and 1.36 s [3H each,
(CH3)2C], 1.43 s (3H, 2′-CH3); 2.11 s, 2.17 s, and
2.25 s (3H each, CH3); 2.61 s (2H, 4′-H), 3.65 d (1H,
22-H, J = 8.0 Hz), 4.13 m (1H, 2-H), 4.17 m (1H,
3-H), 4.69 s (2H, OCH2Ph), 5.22 br.s (1H, 2′′′-H),
13
5.82 s (1H, 7-H), 7.35–7.50 m (5H, Harom). C NMR
spectrum, δC, ppm: 11.93, 12.01, and 12.89 (CH3);
17.04 (C18), 20.58 (C4′, C19), 21.21 (C11), 21.92 (C16),
23.61 (C21), 24.54 (C23), 24.76 (2′-CH3), 26.90 and
29.00 [(CH3)2C], 29.23 (C26), 29.66 (C27), 30.97 (C15),
31.60 (C4), 31.85 (C3′), 34.77 (C12, C9), 37.75 (C1),
38.35 (C10), 41.39 (C24), 45.52 (C13), 47.49 (C5), 49.02
(C17), 50.09 (C1′′′), 70.37 (C25), 73.15 (C2′), 74.76
(OCH2Ph), 77.44 (C3), 77.33 (C2), 82.01 (C22), 84.44
(C20), 84.74 (C14), 101.97 (C2′′′), 117.05 (C8a′), 121.24
(C7), 123.03 (C8′), 126.06 (C7′), 127.77 (C5′), 127.80
and 128.47 (Carom), 137.95 (OCH2C), 147.45 (C4a′),
148.36 (C6′), 163.44 (C8), 202.62 (C6). Found, %:
C 74.00; H 9.01. C52H72O9. Calculated, %: C 74.25;
H 8.63.
1
Compound VIII. mp 129–131°C. H NMR spec-
trum, δ, ppm: 0.98 s (3H, C19H3), 1.08 s (3H, C18H3),
1.23 s (3H, C21H3), 1.25 s (6H, C26H3, C27H3), 1.33 s
and 1.36 s [6H, (CH3)2C], 1.45 s (3H, 2′-CH3); 2.11 s,
2.18 s, and 2.23 s (3H each, CH3); 2.63 m (2H, 4′-H),
3.73 d (1H, 22-H, J = 8.8 Hz), 4.08 m (1H, 2-H),
4.12 m (1H, 3-H), 4.70 s (2H, OCH2Ph), 5.17 m (1H,
2′′′-H), 5.95 (1H, 15-H), 6.11 s (1H, 7-H), 7.35–7.50 m
(5H, Harom). 13C NMR spectrum, δC, ppm: 11.90, 11.99,
and 12.86 (CH3); 19.13 (C18), 20.41 (C4′), 20.58 (C11),
22.64 (C21), 23.24 (C4), 23.73 (C23), 24.76 and 24.83
(2′-CH3), 27.35 (C19), 29.23 (C26), 29.66 (C27), 29.70
[(CH3)2C], 31.62 (C12), 31.97 (C3′), 38.35 (C10), 38.54
(C9), 38.95 (C16), 39.59 (C24), 41.24 (C1), 45.37 and
45.51 (C1′′′), 47.52 (C13), 50.74 (C5), 57.57 (C17), 70.92
(C25), 73.62 and 73.99 (C2′), 74.76 (OCH2C), 76.73
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

(6-BENZYLOXY-2,5,7,8-TETRAMETHYLCHROMAN-2-YL)ACETALDEHYDE
13C NMR spectrum, δC, ppm: 11.31, 11.85, and 12.25
1161
REFERENCES
(CH3); 17.04 (C18), 20.56 (C19), 20.57 (C4′), 21.17
(C11), 21.88 (C16), 23.58 (C21), 24.40 (C23), 24.50
(2′-CH3), 26.85 and 28.96 [(CH3)2C], 29.22 (C26),
29.62 (C27), 30.98 (C15), 31.67 (C4), 31.96 (C3′), 34.76
(C9), 34.77 (C12), 37.77 (C1), 38.34 (C10), 41.38 (C24),
45.42 (C5), 47.47 (C13), 49.02 (C17), 50.79 (C1″′), 70.39
(C25), 73.29 (C2′), 77.03 (C2), 77.35 (C3), 82.00 (C22),
84.40 (C20), 84.95 (C14), 101.99 (C2′′′), 116.73 (C8a),
118.69 (C5″), 121.33 (C7), 122.64 (C7′), 122.99 (C8′),
144.79 (C4a″), 145.10 (C6′), 163.44 (C8), 202.82 (C6).
Found, %: C 71.50; H 9.00. C45H66O6. Calculated, %:
C 71.90; H 8.78.
1. Akhrem, A.A. and Kovganko, N.V., Ekdisteroidy.
Khimiya i biologicheskaya aktivnost’ (Ecdysteroids.
Chemistry and Biological Activity), Minsk: Nauka i
Tekhnika, 1989, p. 325.
2. Kovganko, N.V., Khim. Prirodn. Soedin., 1997, vol. 33,
no. 5, p. 655.
3. Lafont, R. and Dinan, L., J. Insect Sci., 2003, vol. 3, p. 1.
4. Bathori, M. and Pongracz, Z., Cur. Med. Chem., 2005,
vol. 12, p. 153.
5. Odinokov, V.N., Galyautdinov, I.G., Nedopekin, D.V., and
Khalilov, L.M., Izv. Ross. Akad. Nauk, Ser. Khim., 2003,
p. 220.
6. Galyautdinov, I.V., Nazmeeva, S.R., Savchenko, R.G.,
Ves’kina, N.A., Nedopekin, D.V., Fatykhov, A.A., Khali-
lov, L.M., and Odinokov, V.N., Russ. J. Org. Chem.,
2004, vol. 40, p. 675.
This study was performed under financial support
by the President of the Russian Federation (project no.
NSh-6079.2008.3) and by the Academy of Sciences of
Bashkortostan Republic.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010