Chemical shifts (
, ppm), spin-spin interaction constants (in Hz)
of hanphilline and its derivatives (5) and (6)
Protons
Compounds
(1) (5) (6)
Ме-4
1,68 broad singlet
1,22 doublet (7,5)
–
Ме-10
1,43 singlet
0,63 singlet
0,63 singlet
Н-1
5,24 broad doublet (3)
–
–
Н-3
4,90 broad doublet of doublets (10;5)
–
4,0 broad doublet of doublets (10;6)
Н-5
4,86 broad doublet (8,5)
–
–
Н-6
4,12 quartet (10;8,5)
4,04 broad triplet (10,5)
3,98 broad triplet (11)
Н-13а
5,52 doublet (3,5)
5,43 doublet (3)
5,43 doublet (3)
Н-13b
6,26 doublet (3,5)
6,10 doublet (3)
6,10 doublet (3)
H-15a –
– 4,95
broad
singlet
H-15b –
– 5,24
broad
singlet
1
H NMR spectra of all obtained compounds were registered on a spectrometer Bruker Avance-400 (operating fre-
quency 400,13 MHz), solvent CDCl
3
, internal reference TMS.
Treatment of hanphilline (1) with perbenzoic acid in chloroform at room temperature led to trans-
condensed β-hydroxyleudesmanolides: 4-epiartekalin (7) andridentin В (8) with 42–45 and 51–53 % yields
(Fig. 3). These eudesmanolides were isolated from plant sources.
1
H-NMR spectrum data of obtained com-
pounds are shown in Table 3.
Figure 3. 4-epiartekalin (7) and andridentin В (8)
Quantum-chemical (semiempirical methods AM1, PM3, MINDO-3 by MOPAC-7) calculations of the
total energies of all cationic intermediates formed during the reaction were carried out in order to confirma-
tion the proposed mechanism of electrophilic 5,10-carbocyclization of hanphilline [5].
O
H
H
H
O
O
O
O
HO
H
H
H
O
O
HO
H
+
(6)
-H
+
-3
-H
+
-15
(5)
A
HO
O
O
(1)
1
4
5
10
2
3
6
7
8
9
11
12
13
14
15
O
O
OH
H
O
H
H
HO
O
O
OH
H
H
H
(7 )
(8 )
N.Merkhatuly, S.B.Abeuova et al.
42
Вестник Карагандинского университета
T a b l e 3
Chemical shifts (
, ppm), spin-spin interaction constants (in Hz)
of hanphilline and its derivatives (7) and (8)
Protons
Compounds
(1) (7) (8)
Ме-4
1,68 broad singlet
1,26 doublet (7,5)
–
Ме-10
1,43 singlet
1,14 singlet
1,05 singlet
Н-1
5,24 broad doublet (3)
3,71 broad triplet (8,5)
3,79 broad doublet of doublets
(11,5;4)
Н-2а
–
2,65 broad doublet (8,5)
2,32 multiplet
Н-2b
–
2,74 broad triplet (7,5)
2,68 multiplet
Н-3
4,90 broad doublet of doublets
(10;5)
–
4,40 broad doublet of doublets
(11;5)
Н-4
– 2,10
multiplet –
Н-5
4,86 broad doublet (8,5)
2,10 multiplet
2,23 broad doublet
Н-6
4,12 quartet (10;8,5)
4,04 triplet (10,5)
4,23 triplet (11)
Н-13а
5,52 doublet (3,5)
5,43 doublet (3)
5,35 doublet (3)
Н-13b
6,26 doublet (3,5)
6,09 doublet (3)
6,14 doublet (3)
Н-15а –
–
5,26
doublet
(1)
Н-15b –
–
5,92
doublet
(1)
1
H NMR spectra of all obtained compounds were registered on a spectrometer Bruker Avance-400 (operating fre-
quency 400.13 MHz), solvent CDCl
3
, internal reference TMS.
The acid-catalyzed cyclization of hanphilline was investigated (Fig. 4). According to generally accepted
ideas, acid-addition to unsymmetrical alkene (for example to Δ
1,10
-double bond of hanphilline) could form
two carbocation: secondary (A) and tertiary (B). Calculations showed an energy preference for carbocation
(A) (E
tot
= –68566 kcal/mol) than (B) ( E
tot
= –68555 kcal/mol) — the difference in energy was 11 kcal/mol.
Subsequent cyclization of carbocation (B) by nucleophilic attack of Δ
4,5
-bond could lead to two bicyclic cati-
ons (C) and (D). Calculations (particularly by PM3 method) showed a greater energy stability for the carbo-
cation (C) (E
tot
= –68584 kcal/mol) than (D) (E
tot
= –68570 kcal/mol). The energy difference was
14 kcal/mol. Carbocation (C) was identical to the intended tertiary cation (A) (see scheme of cyclization with
formic acid). In this case, stabilization of this cation by deprotonation could form eudesmanolides (5)
and (6). In this way, quantum-chemical calculations confirmed the proposed mechanism of trans-
eudesmanolides formation.
Figure 4. Basic carbocations of acid cyclization of hanphilline
Practically significant eudesmanolides were synthesized with hanphilline electrophilic carbocyclization
reactions. It was found that double bond at С
4
-С
5
did not react in the electrophilic addition reaction. Obvi-
HO
O
O
HO
O
O
HO
O
O
HO
O
O
A
B
C
D
Stereocontrolled synthesis of trans-eudesmanolides …
Серия «Химия». № 3(75)/2014
43
ously, this was in consequence of steric difficulty or electronic factors (otherwise, we would have other types
of skeletal sesquiterpenoids). It was shown that the variation of electrophilic reagents led to synthesis of dif-
ferent functionalized at С-1 and С-3 trans-eudesmanolides and well-known natural trans-eudesman
sesquiterpenoids. It allowed for us to develop the one-step method for the synthesis of practically significant
heteroatomic trans-eudesmanolides.
References
1 Рыбалко К.С. Природные сесквитерпеновые лактоны. — М.: Медицина, 1978. — 320 с.
2 Адекенов С.М., Кагарлицкий А.Д. Химия сесквитерпеновых лактонов. — Алма-Ата: Ғылым, 1990. — 187 c.
3 Гафуров Н.М., Адекенов С.М. Химия и биологическая активность сесквитерпеновых
-лактонов. — Караганда: Изд-
во КарГУ, 2002. — 90 с.
4 Адекенов С.М., Мухаметжанов М.Н., Кагарлицкий А.Д., Турмухамбетов А.Ж. Химическое исследование Achillea
nobilis // Химия природ. соед. — 1984. — № 5. — С. 603–607.
5 Мерхатулы Н., Жокижанова С.К., Адекенов С.М. Квантовохимическое исследование трансаннулярной циклизации
Е,Е-гермакранолида ханфиллина // Развитие фитохимии и перспективы создания новых лекарственных препаратов. Кн. 2.
Биологически активные вещества из растений, их химическая модификация и биоскрининг. — Алматы: Ғылым, 2004. —
С. 170–177.
Н.Мерхатұлы, С.Б.Əбеуова, П.Войтичек, А.Т.Омарова, Л.Т.Балмағамбетова
(+)-Ханфиллиннің транс-эвдесманолидтерінің стереобақыланған синтезі
Мақалада ханфиллин Е,Е-гермакранолидтердің тəжірибелік маңызды транс-конденсацияланған
эвдесманолидтерінің бағытталған синтезі қарастырылды. Алынған транс-эвдесманолидтердің синтезі
(+)-ханфиллин Е,Е-гермакранолидтің стереобақыланған 5,10-карбоциклденуімен жүргізілді. Ол 5,10-
карбоциклдену механизмдері кванттыхимиялық есептеулер нəтижелерімен сəйкес келді.
Электрофильді реагенттерді қолданып, əр түрлі эвдесманды сесквитерпеноидтарды синтездеп алуға
болатыны көрсетілді. Транс-эвдесманолидтердің С-1 жəне С-3 бойынша бірсатылы синтездеп алу
əдісі ұсынылды.
Н.Мерхатулы, С.Б.Абеуова, П.Войтичек, А.Т.Омарова, Л.Т.Балмагамбетова
Стереоконтролируемый синтез транс-эвдесманолидов из (+)-ханфиллина
В статье рассмотрены подходы к направленному синтезу практически значимых эвдесманолидов из
гермакранолида Е,Е-ханфиллина. Синтез полученных транс-эвдесманолидов был осуществлен сте-
реоконтролируемой 5,10-циклизацией Е,Е-гермакранолида (+)-ханфиллина. Рассмотренные механиз-
мы 5,10-карбоциклизации ханфиллина согласуются с результатами квантовохимических расчетов ве-
личин полных энергий всех образующихся в ходе реакции катионных интермедиатов. Показано, что
электрофильные реагенты могут синтезировать различные эвдесмановые сесквитерпеноиды. Разрабо-
тан одностадийный метод синтеза функционализированных при С-1 и С-3 транс-эвдесманолидов.
References
1 Rybalko K.S. Natural sesquiterpene lactones, Мoscow: Мeditsina, 1978, 320 p.
2 Adekenov S.M., Kagarlitskiy A.D. Chemistry of sesquiterpene lactones, Alma-Ata: Gylym, 1990, 187 p.
3 Gafurov N.M., Adekenov S.M. Chemistry and biological activity of sesquiterpene γ-lactones, Karaganda: KarSU Publ.,
2002, 90 p.
4 Adekenov S.M., Mukhametzhanov M.N., Kagarlitskiy A.D., Turmukhambetov A.Zh. Chemistry of natural compounds,
1984, 5, p. 603–607.
5 Merkhatuly N., Zhokizhanova S.K., Adekenov S.M. The development of Phytochemistry and prospects for new drugs, B. 2,
Biologically active substances from plants, their chemical modification and bioscreening, Almaty: Gylym, 2004, p. 170–177.
44
Вестник Карагандинского университета
UDC 547.314
N.Merkhatuly, S.B.Abeuova, A.T.Omarova, L.T.Balmagambetova
E.A.Buketov Karaganda State University
(E-mail: merhatuly@ya.ru)
Synthesis of guaian sesquiterpene γ-lactones from hanphilline
Synthetic methods of guaianolides on the basis of germacranolide E,E-hanphilline were presented in this arti-
cle. Hanphilline is a characteristic component of the Noble Yarrow (Achillea nobilis L.), which is widespread
in Central Kazakhstan. Synthesis of obtained guaianolides were carried out with stereocontrolled
1,5-cyclization of E,E-germaсranolide (+)-hanphilline. The one-step stereospecific syntheses of guaianolides
on the basis of available germacradienolide E,E-hanphilline were developed and carried out. The mechanism
of 1,5-carbocyclization was considered. Scheme of biogenetic interdependence of guaianolides in Achillea
nobilis L. was offered. It allowed a deeper understanding of a very complex process of biosynthesis of
sesquiterpene lactones in the plant body.
Key words: sesquiterpene lactones, guaianolides, germacranolides, stereocontrolled synthesis, hanphilline,
carbocyclization, biogenetic interdependence, quantum-chemical calculations.
Sesquiterpene γ-lactones, in particular guaianolides and germacranolides, are widespread in flowering
plants of the family Asteraceae (Acteraceae). They are valuable natural compounds for studying various re-
actions and synthesis of new biologically active derivatives [1].
Synthesis methods of guaianolides on the basis of germacranolide E,E-hanphilline were presented in
this work. Hanphilline is a characteristic component of the Noble Yarrow (Achillea nobilis L.), which is
widespread in Central Kazakhstan [2].
Reaction of electrophilic cyclization of hanphilline (1) occurred through Δ
1,10
-double bond. Investiga-
tion of cyclization by activation of second Δ
4,5
-double bond arouse interest for us (because other skeletal
types of sesquiterpenoids could be formed) [3, 4]. It was necessary to induce allyl cation (in the molecule,
namely the carbon C
3
-C
4
-C
5
) by cleavage of the hydroxyl group at C
3
.
In connection with it, reactions of hanphilline with dehydrating reagents were investigated. Selective
and widespread in chemistry of natural compounds p-toluenesulfonyl chloride (TsCl) and methyl
sulfochloride (MsCl) were used in the capacity of dehydrating reagents.
Treatment of hanphilline (1) with tosyl chloride in pyridine at 80 ºС gave chiral cis-condensed
5(α),10(α)-guaianolides — (2) and (3) with 55 and 30 % yields (Fig. 1).
1
H-NMR spectrum data of obtained
compounds are shown in Table 1.
Figure 1. The obtaining of guaianolides (2) and (3)
O
O
H
H
+
À
O
O
H
H
H
H
O
O
H
H
H
TsO
O
O
-TsOH
-H
+
-14
(2)
(3)
-H
+
-1
HO
O
O
(1)
1
4
5
10
2
3
6
7
8
9
11
12
13
14
15
Synthesis of guaian sesquiterpene …
Серия «Химия». № 3(75)/2014
45
T a b l e 1
Chemical shifts (
, ppm), spin-spin interaction constants (in Hz)
of hanphilline and its derivatives (2) and (3)
Protons
Compounds
(1) (2)
(3)
Ме-4
1,68 broad singlet
1,61 broad singlet
1,60 broad singlet
Ме-10
1,43 singlet
–
1,81 singlet
Н-1
5,24 broad doublet (3)
–
–
Н-3
4,90 broad doublet of doublets (10;5)
4,87 broad doublet (3)
4,87 broad doublet (3)
Н-5
4,86 broad doublet (8,5)
2,15 multiplet
2,15 multiplet
Н-6
4,12 quartet (10;8,5)
3,97 triplet (10, 5)
4,10 triplet (10, 4)
Н-13а
5,52 doublet (3,5)
5,44 doublet (3)
5,44 doublet (3)
Н-13b
6,26 doublet (3,5)
6,15 doublet (3)
6,15 doublet (3)
Н-14а – 4,78
broad
singlet –
Н-14b – 4,78
broad
singlet –
1
H NMR spectra of all obtained compounds were registered on a spectrometer Bruker Avance-400 (operating fre-
quency 400,13 MHz), solvent CDCl
3
, internal reference TMS.
As we can see from the scheme, cleavage of intermediate sulfoester С
3
-ОН group initiated stereo-
controlled electrophilic rearrangement (a resonantly stabilized allyl cation could be formed). It led to
1,5-cyclization by Markovnikov's rule and formation of the most stable guaian carbocation (A). Further sta-
bilization of carbocation (A) through regioselective deprotonation (Hofmann’s rule) led to final guaianolides
(2) and (3). A similar result was obtained by treatment (1) with mesyl chloride in pyridine under reflux,
which also led to the stereocontrolled formation of isomeric cis-guaianolides (2) and (3) with 54 and 31 %
yields.
Quantum-chemical calculations (Table 2) of the total energies of all cationic intermediates formed dur-
ing by cleavage of hydroxyl group did not reveal an energy preferableness of one of the two resonant struc-
ture of allyl cation (А, В). It was found that they had the same total energy (E
tot
= –61057 kcal/mol) [5].
T a b l e 2
Quantum-chemical calculations of the total energies of all cationic intermediates
E
tot
, kcal/mol
Compound 1 А
В C D
РМ3
–68400,984 –61056,932 –61056,965 –61062,342 –61081,231
Further cyclization of the most preferable (from the viewpoint of structure) allyl cation (B) could lead
to bicyclic cation (С) and (D). The guaian cation (D) (identical to carbocation (A)) was the most energetical-
ly stable than (C). The difference in energy was 19 kcal/mol. Therefore the further cyclization by
deprotonation led to guaianolides (2) and (3). Thus, quantum-chemical calculations of the total energies of
all cationic intermediates confirmed the proposed mechanism of cis-guaianolides formation.
O
O
O
O
O
O
A
B
D
O
C
O
+
+
+
+
N.Merkhatuly, S.B.Abeuova et al.
46
Вестник Карагандинского университета
Thus, it was found that the cleavage of the C
3
-OH group of hanphilline activated Δ
4,5
-double bond and
initiated intramolecular 1,5-carbocyclization which led to only cis-condensed guaian structures. The cycliza-
tion was stereospesific and completely controlled by conformation of chiral hanphilline.
Namely the stereocontrolled synthesis of cis-guaianolides (2) and (3) allowed us to develop a scheme of
biogenetic interdependence of guaian sesquiterpene γ-lactones in Noble Yarrow (Achillea nobilis L.),
(Fig. 2).
Figure 2. Scheme of biogenetic interdependence of guaianolides in
Achillea nobilis
L.
As we can see, reaction of 1,5-carbocyclization of hanphilline (key stage) led through bicyclic cation
(A) to guaianolides (2) and (3). In further successive regio- and stereoselective reaction of epoxidation,
isomerization and hydrolysis led to guaianolides: estafiatin (4), anolide (5), anobin (6), canin (7) and
khrizartemin A (8). The epoxidation reaction was an important step for the introduction of the oxygen atom
in the molecular structure. Proposed way of biogenetic interdependence confirmed fact that guaianolides (4),
(5), (6), (7) and (8) were isolated from the aboveground part of Yarrow Noble. Furthermore, it became ap-
parent that hanphilline was a biogenetic predecessor of these guaianolides in the plant organism. Because, it
was isolated from the Noble Yarrow by water extraction method, too [2].
HO
O
O
O
O
Z
O
O
A
-H
-1
O
O
(2)
O
O
(3)
O
O
O
(4)
O
O
O
O
O
O
O
O
O
O
O
HO
HO
O
O
HO
O
O
OH
O
O
HO
O
O
HO
O
O
O
O
O
O
OH
O
O
HO
OH
O
O
HO
O
OH
H
+
H
+
H
3
O
+
H
+
H
3
O
+
(1)
(5)
(6)
(7)
(8)
+
H
+
-14
Synthesis of guaian sesquiterpene …
Серия «Химия». № 3(75)/2014
47
Thus, the one-step stereospesific syntheses of cis-guaianolides were carried out and developed. We
chose germacradienolide hanphilline, easily available sesquiterpene, as the starting material. The key stage
was the dehydration reaction. In addition the scheme of biogenetic interdependence of guaianolides in
Achillea nobilis L. was developed. It allowed a deeper understanding of a very complex process of biosyn-
thesis of sesquiterpene lactones in the plant body.
References
1 Рыбалко К.С. Природные сесквитерпеновые лактоны. — М.: Медицина, 1978. — 320 с.
2 Адекенов С.М., Мухаметжанов М.Н., Кагарлицкий А.Д., Турмухамбетов А.Ж. Химическое исследование Achillea
nobilis // Химия природ. соед. — 1984. — № 5. — С. 603–607.
3 Мерхатулы Н., Жокижанова С.К., Балмагамбетова Л.Т., Адекенов С.М. Трансаннулярная карбоциклизация ханфил-
лина N-бромсукцинимидом // Журнал общей химии РАН. — 2006. — Т. 76(138), Вып. 8. — С. 1403–1404.
4 Мерхатулы Н. Реакции внутримолекулярной карбоциклизации ханфиллина // Вестн. Караганд. ун-та. Сер. Химия. —
2008. — № 2(50). — С. 46–51.
5 Мерхатулы Н., Жокижанова С.К., Адекенов С.М. Квантовохимическое исследование трансаннулярной циклизации
Е,Е-гермакранолида ханфиллина // Развитие фитохимии и перспективы создания новых лекарственных препаратов. Кн. 2.
Биологически активные вещества из растений, их химическая модификация и биоскрининг. — Алматы: Ғылым, 2004. —
С. 170–177.
Н.Мерхатұлы, С.Б.Əбеуова, А.Т.Омарова, Л.Т.Балмағамбетова
Ханфиллиннен гваянды сесквитерпенді γ-лактондарды синтездеп алу
Мақалада сесквитерпенді γ-лактон Е,Е-ханфиллиннен гваянолидтерді синтездеп алу əдістері
қарастырылды. Бұл қосылыс Орталық Қазақстанда кеңінен таралған асыл мыңжапырақтан (Achillea
nobilis L.) бөлініп алынды. Алынған гваянолидтердің синтезі (+)-ханфиллиннің Е,Е-гермакранолиді-
нің стереобақыланған 1,5-циклденуімен жүргізілді. Ханфиллиннен цис-гваянолидтердің бірсатылы
стереоспецификалық синтездеп алу əдістері ұсынылып, жүргізілді. 1,5-карбоциклденудің механизмі
зерттеліп, Achillea nobilis L. өсімдігінде гваянолидтердің биогенетикалық өзара байланысының сызба-
сы ұсынылды.
Н.Мерхатулы, С.Б.Абеуова, А.Т.Омарова, Л.Т.Балмагамбетова
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