2000 hippocratea diels alder aducts

1. Two novel Diels–Alder adducts from Hippocratea
celastroides roots and their insecticidal activity
M. Jiménez-Estrada, R. Reyes-Chilpa, S. Hernández-Ortega,
E. Cristobal-Telésforo, L. Torres-Colín, C.K. Jankowski, A. Aumelas,
and M.R. Van Calsteren
Abstract: Two novel compounds, celastroidine A (1) and B (2), were isolated from the roots of Hippocratea
celastroides K. Their structures were elucidated by spectroscopical and X-ray diffraction studies. Celastroidine A (1)
(C50H74O5) was identified as a Diels–Alder adduct of a triterpene plus a diterpene and celastroidine B (2) as a
beyerane, a type of dimer of two diterpene (C40H60O4). Both compounds could be formed in vivo by a Diels–Alder
reaction. Celastroidine A showed some antifeeding activity against the stored grain insect Sitophyllus zeamays.
Key words: Hippocratea celastroides, Hippocrataceae, roots, Diels–Alder adducts, diterpenoids, triterpenoids, x-ray
diffraction, insect antifeedants, stored grain insects, Sitophyllus zeamays, insecticidal plants, Diels–Alderase.
Résumé : Deux nouveaux terpènes, célastroïdines A (1) et B (2) ont été isolés à partir des racines d’Hippocratea
celastroides K. Leurs structures ont été étudiées par des méthodes spectroscopiques (en particulier par RMN et rayons
X). La célastroïdine A (1), un pentaterpène, a été identifié comme l’adduit du type de Diels–Alder entre des résidus
di- et triterpéniques et la célastroïdine B (2) comme un dimère beyerane à C40 résultant de l’addition de deux unités
diterpéniques réagissant en tant que diène et diènophile. Les deux substances peuvent être formées in vivo suite à cette
addition. La célastroïdine A (1) montre une activité bloquant le réflexe d’alimentation chez les insectes de stockage de
grains Sitophyllus zeamays.
Mots clés : Hippocratea celastroides, hippocratacées, racines, adduits de Diels–Alder, diterpénoïdes, triterpénoïdes,
diffraction des rayons X, antiappétants pour les insectes, insectes de stockage de grains, Sitophyllus zeamays, plantes
insecticides, Diels–Aldérase. Jiménez-Estrada et al. 254
248
Introduction
Hippocratea celastroides Kunth (also known as H.
acapulcensis) is a shrubby vine which grows in the tropical
deciduous forest in Mexico. The seeds and fruits are used in
folk-medicine against head lice and skin mite parasites
(1, 2). In a previous work, we reported that the organic ex-tracts
from the roots, especially acetone and methylene chlo-ride
extracts, have antifeeding activity against the stored grain
insect Sitophyllus zeamays.2 Chemical studies have shown
that H. celastroides leaves contain the triterpenes: friedelin,
friedelan-3b-ol (epifriedelinol), 3-oxo-lup-20-en-30-ol, and
lup-20-en-3b,30-diol (3), meanwhile the roots contain the
alditol galactitol.2 Continuing our studies on H. celastroides
roots, we wish now to report the isolation and structure elu-cidation
of two novel compounds celastroidine A (1) and B
(2) (Fig. 1), as well as the evaluation of their toxicity and
antifeedant activity against S. zeamays.3
Toxicity and antifeeding properties of celastroidine A and
B were examined against the stored grain pest S. zeamays.
Celastroidine A (1) inhibited the feeding of the insect in
88.7%, but only increased mortality in 2%. On the other
hand, celastroidine B (2) showed both low antifeeding activ-ity
(9.6%) and mortality (5.2%) rates. We have previously
Received September 8, 1999.
M. Jiménez-Estrada, R. Reyes-Chilpa, S. Hernández-Ortega, and E. Cristobal-Telésforo. Instituto de Química. Universidad
Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria, Coyoacán, 04510, México D.F.
L. Torres-Colín. Instituto de Biología. Universidad Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria,
Coyoacán, 04510, México D.F.
C.K. Jankowski,1 A. Aumelas, and M.R. Van Calsteren. FESR Université de Moncton, Moncton, NB E1A 3E9, Canada.
1Author to whom correspondence may be addressed. Département de chimie et biochimie, Université de Moncton, Moncton, NB
E1A 3E9, Canada. Telephone (506) 858-4331. Fax:(506) 858-4541. e-mail: jankowc@umoncton.ca
2R. Reyes Chilpa, M. Jiménez-Estrada, E. Cristobal-Telésforo, L. Torres-Colín, M.A. Villavicencio, B.E. Pérez Escandón, and R.
Mercado. Natural insecticides from Hippocratea excelsa and Hippocratea celastroides. Submitted to Economic Botany (1999).
3Tables of crystallographic details, atomic coordinates, anisotropic displacement coefficients, and bond distances and angles have
been deposited and may be purchased from: The Depository of Unpublished Data, Document Delivery, CISTI, National Research
Council Canada, Ottawa, Ontario, Canada, K1A 0S2. Tables of bond distances and angles and H coordinates have also been
deposited with the Cambridge Crystallographic Data Centre and can be obtained on request from: The Director, Cambridge
Crystallographic Data Centre, University Chemical Laboratory, 12 Union Road, Cambridge, CB2 1EZ, U.K.
Can. J. Chem. 78: 248–254 (2000) © 2000 NRC Canada
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

2. Jiménez-Estrada et al. 249
reported that the total methylene chloride extract from H.
celastroides roots has good antifeeding activity (70.3%) and
low mortality (9.4%) when tested with S. zeamays.2 The
celastroidine A activity is quite similar and since is the most
abundant component of this extract (~10.7%), and it seems
to be its active principle.
Results and discussion
The methylene chloride root extract afforded celastroidine
A (1) and B (2) in good yield. The petroleum ether extract
produced celastroidine B and b-sitosterol. Celastroidine A
was isolated as a white powder. According to spectral and
X-ray diffraction evidence, the celastroidine A molecular
structure corresponds to a Diels–Alder adduct of a triterpene
on a diterpene (1). The IR spectrum showed absorption
bands (cm–1) for hydroxyl (3565) together with a lactone
carbonyl (1759) and two ketones on the six member rings
(1709 broad). The FAB mass spectrum confirmed the molec-ular
mass at 754 corresponding to the formula C50H74O5.
Fragments of m/z 737 and 452 were attributed to the loss of
water (MH+–18), and to a lupen triterpene C30H42O3 moiety
(fragment a) as indicated in Fig. 2 from the protonated mo-lecular
ion. This last fragment also appeared in the EIMS
and CIMS (as the quasimolecular ion). The difference
among M+ and fragment a accounts for m/z 302, equivalent
to the molecular weight of a C20H32O2 diterpene of the
abietane type (fragment b). In addition, FABMS showed a
peak at m/z 285 corresponding to fragment c originated from
fragment b by loss of OH followed by ring aromatization.
Fragment d (at m/z 165) could also be related to b (Fig. 2).
Structures 1 and 2 were supported by the 1HNMR and
13CNMR data. The assignment of their 1H and 13 C spectra
was carried out from the analysis of a COSY, TOCSY,
HSQC, and HMBC experiments (Table 1). The 13C NMR
(DEPT) spectrum of the compound 1 indicated 45 sp3 car-bon
atoms, 11 methyls, 15 methylenes, 10 methines, nine
quaternary C, and five sp2 carbons (3 C=O, and 2 C=C).
Celastroidine A (1) has 11 methyl signals, five of them are
part of the diterpene moeity, and six to the triterpene moiety.
This part of the skeleton is related to lupene triterpenoids
previously isolated from the same species (3). Further evi-dence
came from comparison of 13C NMR data of three
compounds to those previously reported (3) (e.g., for 3-oxo-
© 2000 NRC Canada
Fig. 1. Structure of celastroidine A (1) (and it’s acetate (1a), celastroidine B (2), and 3-oxolup-20-en-30-ol (3).
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

3. 250 Can. J. Chem. Vol. 78, 2000
lup-20-en-30-ol (3) (Table 1, Fig. 1)). From this comparison,
the signal at 217.9 ppm was readily assigned to the C-3
ketone. Therefore the signal at 213.4 ppm was assigned to
the C-12¢ ketone. This carbon showed couplings with H-11¢
(2.92 ppm) and H-14¢ (2.74 ppm).
Finally, the signal at 177.7 ppm was assigned to the C-30
carbonyl of a g-lactone ring. This ring was indirectly con-firmed
by the presence of a tertiary carbon in position 21
whose 13C (81.1 ppm) and 1H (5.02 ppm) chemical shifts are
typical of an ether or ester substitution. As expected, the
COSY experiment showed interactions of H-21 proton with
another tertiary proton (H-19 2.49 ppm) and with H-22
methylene protons (2.15 and 1.29 ppm). On the diterpene
moiety the molecule bears one double bond and an isopropyl
group. The C-8¢—C-9¢ double bond is unambiguously char-acterized
by carbon signals at 136.1 and 134.9 ppm, respec-tively.
The isopropyl group was clearly identified with 1H spec-trum
by the presence of two doublets for methyl groups at
0.84 (CH3-16¢) and 0.97 (CH3-17¢) ppm coupled to the H-15¢
proton (1.78 ppm).
The bridge between diterpene and triterpene moieties was
evidenced by HMBC and COSY experiments. For instance,
H-14¢ (2.74 ppm) on the diterpene side showed a long dis-tance
coupling with C-29 (23 ppm) on the triterpene side.
The C-12¢ signal showed couplings with H-11¢ (2.92 ppm)
and H-14¢ (2.74 ppm).
Celastroidine A (1) did not hydrolyze under mild acidic
conditions (HCl (aq)) and was recovered unaltered, exclud-ing
the possibility of an ether bridge presence. Acetylation
under mild conditions with acetic anhydride in pyridine did
not work, but the compound could be reduced with NaBH4
in THF. The product 1a, was a white solid. The IR spectrum
did not show any carbonyl absorption, nevertheless hydroxyl
bands were evident. The 1HNMR spectrum showed a
multiplet centered at 4.19 ppm which was assigned to the
H-3 proton. This signal was duplicated and suggested a
stereoisomer mixture. Two doublets, at 1.17 and 1.38 ppm,
were assigned to C-16¢ and C-17¢. Other methyl signals ap-pear
among 1.2–1.4 ppm (7 singlets). The FAB mass spec-trum
showed the molecular ion at m/z 760 (3), and others
similar to 1 fragments e.g., loss of water. Structure 1 was
definitely confirmed by X-ray diffraction (Fig. 3).
Celastroidine B (2) was also isolated as a white powder.
The IR spectrum showed two carbonyl absorptions at 1608
and 1712 cm–1 of a conjugated and deconjugated cyclo-hexenone
respectively. Its molecular structure was deduced
as 2 and corresponds to a C40H60O4 diterpene dimer formed
by a Diels–Alder reaction (Fig. 1). The PI mass spectrum
obtained by FAB and EIMS showed the 100% ion at m/z 302
and the molecular mass at 604, therefore suggesting that
compound 2 could be formed by attachment of two identical
C20H30O2 fragments. This retro-Diels–Alder fragment struc-ture
should be considered as a hypothetical diene (or dieno-phile)
leading to formation of either 1 or 2. This fragment is
more intense (100%) for dimer 2 than for celestroidine A (1)
(54%) for which it plays a role of diene only. A fragment
of m/z 165 was also noticed and corresponds to structure d
(Fig. 2).
1HNMR and 13CNMR spectra (Table 2) suggested that the
diterpene monomer has an abietane type skeleton, as already
indicated for celastroidine A (1). All assignments were
© 2000 NRC Canada
Fig. 2. Fragmentation pattern of celastroidine A (FAB)
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

4. Jiménez-Estrada et al. 251
Table 1 (concluded).
supported by homo- and heteronuclear NMR experiments.
Two methine doublets at 3.11 ppm (J = 2.5 Hz) and
2.56 ppm (J = 2.5 Hz) integrating for one proton were as-signed
to H-14 and H-14¢, respectively. Carbons C-14 and
C-14¢ bearing these protons, appeared at 45.4 and 43.3 ppm
(Table 2). A singlet at 6.15 ppm was assigned to the
vinylic proton H-11¢ of the a,b-unsaturated ketone system.
Carbons C-11¢ and C-9¢ supporting this double bond position
were assigned at 120.0 (C-11¢) and 172.6 ppm (C-9¢). The
second diterpene unit should bear a nonprotonated double
bond as indicated by signals at 138.6 and 138.5, that corre-sponded
to C-8 and C-9. A broad singlet at 3.46 ppm was
assigned to H-11, while the carbon bearing this proton ap-peared
at 57.8 ppm (CH). Two quaternary carbons appeared
at 78.7 (C) and 76.1 (C) and correspond to C-13¢ and C-13,
respectively. Both carbons are substituted with a hydroxyl
group. Ketone carbonyls on C-12¢ and C-12 appeared at
200.6 and 213.4 ppm. A doublet at ~0.53 ppm was assigned
to H-17¢. Signals for nine additional methyls were also as-signed
as in the Table 1. The structure of 2 was confirmed
by the X-ray diffraction studies (Fig. 4).
The preliminary molecular mechanics modeling of the
stereochemistry of the central part of the celastroidine B (2)
indicates a photochemical pathway for the retro Diels–Alder
reaction leading to the monomeric dienone of fragment
b-like structure. The mechanism of the formation and its
stereoselectivity should be fully analyzed (endo/exo and spe-cific
diastereofacial stereochemistry of adducts).
Celastroidine A and B are Diels–Alder adducts. Several
natural products, presumably arising from a Diels–Alder re-action,
according to metabolic or enzymatic pathways, have
previously been isolated from microorganisms, plants, and
marine animals. These compounds included polyketides, ter-penoids,
and alkaloids (4). Involvement of the Diels–Alder
reaction in biosynthesis has been suggested, but a definitive
proof has been lacking due to unsuccessful attempts to ob-tain
the corresponding enzymes or starting diene (5). Never-theless,
the isolation of a crude enzyme from the
phytopathogenic fungus Alternaria solanii has recently been
reported enable to catalyze the [4 + 2] cycloadditions (e.g.,
necessary to synthesize two solanopyrones phytotoxins) (4).
Isolation of celastroidine A and B, therefore suggests that
© 2000 NRC Canada
Table 1. 13C and 1H NMR data of Celastroidine A (1) and
3-oxo-lup-20-en-30-ol (3). (CDCl3, 27°C).
1 3
C no. dC (ppm) dH (ppm) J (Hz) dC (ppm)
1 39.6 1.94 eq 13.2 7.3 4.7 39.9
1.42 ax
2 34.0 2.5 ax 34.1
2.44 eq
3 217.9 — 215.0
4 47.2 — 47.6
5 54.6 1.33 55.2
6 19.6 1.48 19.8
1.48
7 33.7 1.44 33.8
1.44
8 41.2 — 41.1
9 48.3 1.37 50.0
10 36.7 — 37.2
11 21.7 1.52 eq 21.7
1.30 ax
12 29.6 1.84 ax 29.8
1.15 eq
13 37.9 1.74 38.2
14 43.1 43.2
15 26.6 1.71 27.5
1.10
16 34.1 1.69 35.6
1.40
17 43.7 — 43.3
18 49.6 1.37 49.1
19 50.4 2.49 10.8 7.3 44.0
20 54.8 — 154.0
21 81.1 5.02 7.4 7.4 5.9 31.2
22 48.0 2.15 eq 13.0 7.6 39.4
1.29 ax
23 26.6 1.07 26.6
24 20.9 1.02 21.2
25 16.0 0.94 15.9
26 15.9 1.07 16.1
27 14.4 0.89 14.6
28 20.1 0.80 17.9
29 23.2 2.41 63.3
1.76 endo 13.7 3.4
30 177.7 — 107.1
1¢ 34.9 1.49 eq
1.40 ax
2¢ 18.5 1.51
1.51
3¢ 41.3 1.38
1.21
4¢ 33.2 —
5¢ 49.4 1.35
6¢ 18.7 1.78
1.47
7¢ 29.5 2.42 ax
2.16 eq
8¢ 136.0 —
9¢ 136.4 —
10¢ 36.3 —
1 3
C no. dC (ppm) dH (ppm) J (Hz) dC (ppm)
11¢ 55.3 2.92
12¢ 213.4 —
13¢ 78.7 —
14¢ 45.3 2.74 3.7 1.9
15¢ 34.1 1.78
16¢ 17.4 0.97 6.7
17¢ 16.9 0.84 7.4
18¢ 32.8 0.90
19¢ 21.4 0.80
20¢ 21.0 0.82
OH13¢ — 2.20
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

5. 252 Can. J. Chem. Vol. 78, 2000
H. celastroides roots could also bear enzymes able to cata-lyze
Diels–Alder reactions.
Experimental
Hippocratea celastroides Kunth was collected near
Tucumán (State of Morelos, Mexico). A voucher is depos-ited
at MEXU Herbarium. The roots (1.610 kg) were ground
and extracted at room temperature with petroleum ether, and
CH2Cl2. The extracts were concentrated under reduced pres-sure.
The CH2Cl2 extract (14.1 g) was dissolved with ace-tone
obtaining a white precipitate (1.4 g). The precipitate
was subjected to column chromatography on silica gel
eluting with petroleum ether (pet et), CH2Cl2, and mixtures
of these solvents. Two products were obtained. Fractions
24–72 eluted with a (7:3) mixture afforded a white powder
(610 mg). This product was recrystallized from CH2Cl2–
MeOH obtaining a crystalline solid (mp 198–9°C).. which
was named as celastroidine A (1). The acetone soluble por-tion
of the CH2Cl2 extract (12.7g) was subjected to CC (Sil-ica
Gel 60) eluting with pet et–CH2Cl2. Fractions 56–65
eluted with a mixture (8:2) yielded 224 mg of a white pow-der
(mp 189–190°C) named as celastroidine B (2). Fractions
66–89 eluted with a mixture (8:2) afforded celastroidine A
(902 mg) again. The pet et extract (6.18 g) under column
chromatography (Silica Gel 60) and elution with mixtures of
petroleum ether–ethyl acetate, also afforded celastroidine B,
especially from fractions 30–42 eluted with a 9:1 mixture.
Insecticidal tests
Toxicity and antifeeding activity of isolated compounds
against Sitophyllus zeamays was evaluated as described.2
Experimental NMR
Materials and methods
The samples were dissolved in CDCl3 and all NMR ex-periments
were recorded at 27° on Bruker spectrometers, op-erating
at 300, 500, and 600 MHz for 1H nucleus and up to
150 MHz for 13C nucleus. Chemical shifts are quoted rela-tive
to the CDCl3 resonance fixed at 7.24 ppm for the proton
and 77.0 ppm for the carbon. The multiplicity of carbon sig-nals
was established by using the DEPT experiment.
DQF–COSY spectra (6) were collected into a 800 × 1024
data matrix with 32 scans per tl value and TOCSY (7) spec-tra
were collected with a mixing time of 80 ms into a 512 ×
1024 data matrix with 16 scans per tl value.
HSQC (8, 9) experiments were recorded with a delay of
3.5 ms (1JCH = 143 Hz) and HSQC–TOCSY (10, 11) experi-ments
with a mixing time for proton–proton transfer of
80 ms (400 × 1024) with 32 scans per tl value to identify the
one-bond carbon–proton and the network of proton–proton
conectivities, respectively. The HMBC experiment (400 ×
10 240) was recorded with a delay of 50 ms with 64 scans
per tl value to identify long range proton–carbon connectivities.
All data were processed with the UXNMR software. For
© 2000 NRC Canada
Fig. 3. X-ray of celastroidine A (1).
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

6. Jiménez-Estrada et al. 253
Table 2. 13C and 1H NMR data of celastroidine B (2).
DQF–COSY and TOCSY data, one zero filling and a p/4
phase-shifted sine bell window function were applied in
1
both dimensions )before Fourier transform. For HSQC,
HSQC–TOCSY, and HMBC data, a zero filling and a p/2
phase-shifted sine bell window function were applied in F2
dimension and a linear prediction was applied to 1024 points
in F1 dimension prior to processing. The assignment of 1H
and 13C resonances of celastroidine A and B spectra was
carried out from analysis of DQF–COSY, TOCSY, DEPT,
HSQC, HSQC–TOCSY, and HMBC data. All 2D NMR data
and additional spectral material are available on request
from CKJ (Moncton, Canada).
Celastroidine A (1): C50H74O5, white powder, mp 198–199°C,
[a] = +7.5° (CHCl3). IR (cm–1), n max, (CHCl3): 3565,
2960, 2873, 1759, 1709, 1462, 1386, 1367, 1311, 1178, and
1145. MS (FAB+) m/z (%): 755 (M+ + 1(5) [C50H74O5],
737 (20), 694 (10), 655 (4), 587 (2), 453 (7), 302 (45), 285
(63), 259 (30), 245 (17),165 (85), 91 (50), 81 (60), 69 (50),
43 (100).
Proton and carbon chemical shifts of 1 measured in CDCl3
at 27°C are reported in Table 1.
X-Ray Structure Analysis Summary (Fig. 3)
Celastroidine A (1): Crystal data: C50H74O5 from CH2Cl2,
crystal dimensions 0.40 × 0.20 × 0.08 mm crystal system,
monoclinic P2(1), cell parameters a = 6.940(1), b = 23.994(3),
c = 14.009(5), b = 95.84(1) Å, Z = 2, V = 2320.6(9) Å3,
Mr = 840.0, Dcalc = 1.202, m = 1.606 mm–1, F(000) = 912.
Data collection: Siemens P4/PC, CuKa radiation (l = 1.54178
Å), q/2q scan, scan range 3–110°, index range 0 £ h £ 7, 0 £
k £ 25, –14 £ I £ 14.3238 collected reflections and 2468 ob-served
reflections [F ³ 3s(F)]. Solution and refinement. The
structure was solved by direct methods and refined by full-matrix
least squares, function minimized S[Fo – Fc]2, hydro-gen
atoms model dC-H = 0.96Å, common fixed isotropic U =
0.06 Å 2. Final values are R = 7.26, wR = 9.44, GOF = 1.47,
weight w–1 = s2 F + 0.0019 F2 secondary extinction correc-tion
c = 0.0022(1), residual electron density: 0.27/ – 0.30
e/Å–3.
Celastroidine B (2): white powder, mp 189–190°C. [a] =
+55.5° (CHCl3). IR (cm–1) n max, CHCl3: 2937, 2875, 1712,
1608, 1602, 1462, 1373, 1155, 1022 MS(%) FAB+ m/z: 605
(12) (M++1), 586(4), 557(3), 487(2), 391(1), 303(43),
302(36), 286(27), 261(25), 245(10), 165(100), 123(32),
69(41), 55(29), 43(62), 41(40), 27(6). IE 70 eV m/z: 604(3),
543(2), 533(3), 344(3), 302(100), 285(15), 259(20), 260(15),
261(10), 245(10), 232(22), 217(6), 165(50), 123(11), 83(6),
69 (12), 71(12), 55(7), 57(7), 43(18).
Proton and carbon chemical shifts of 2 measured in
CDCl3 at 27°C are reported in Table 2.
X-Ray Structure Analysis Summary (Fig. 3)
Celastroidine B (2): Crystal data: C49H60O4, colorless and
prism crystal of dimensions 0.40 × 0.24 × 0.16 mm, system
orthorombic P2(1)2(1)2(1), cell parameters a = 10.589 (2),
b = 15.607(3), c = 21.649(2) Å, Z = 4, V = 3577.7(9) Å3,
Mr = 604.9, Dcalc = 1.123, m = 0.542 mm–1, F(000) = 1328.
Data collection: Siemens P4/PC, CuKa radiation (l = 1.54178 Å),
q/2q scan, scan range 3–110°, index range –11 £ h £ 0, –16 £
k £ 16, –22 £ I £ 0.4774 reflections collected and 3659 ob-
© 2000 NRC Canada
2
C no. dC (ppm) dH (ppm) J (Hz)
1 36.2 1.30 eq
1.08 ax
2 18.4 1.53
1.46
3 41.6 1.39
1.15
4 33.1 —
5 49.2 1.05 12.5 1.9
6 18.6 1.69 eq
1.34 ax
7 29.4 2.09
2.00
8 138.6 —
9 138.5 —
10 37.3 —
11 57.8 3.46
12 213.4 —
13 76.1 —
14 45.0 3.11 2.5
15 34.6 1.60
16 17.0 0.97 6.9
17 17.6 0.96 7.4
18 33.0 0.89
19 21.3 0.76
20 20.8 0.76
1¢ 37.0 1.97 eq
1.40 ax
2¢ 18.8 1.67
1.60
3¢ 41.8 1.49
1.12
4¢ 34.0 —
5¢ 43.0 1.75 11.6 8.0
6¢ 16.4 2.08 eq
1.50 ax
7¢ 30.9 1.98
1.91
8¢ 48.4 —
9¢ 172.6 —
10¢ 42.0 —
11¢ 120.0 6.15
12¢ 200.6 —
13¢ 78.7 —
14¢ 43.3 2.56 2.4
15¢ 37.0 1.50
16¢ 15.4 0.94 6.3
17¢ 16.2 0.53 6.7
18¢ 32.9 0.95
19¢ 21.1 0.95
20¢ 26.5 1.0
OH13 — 2.10
OH13¢ 3.74
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

7. 254 Can. J. Chem. Vol. 78, 2000
© 2000 NRC Canada
served reflections [F ³ 3s(F)]. Solution and refinement. The
structure was solved by direct methods and refined by
full-matrix least squares, function minimized S[Fo – Fc]2,
hydrogen atoms model dC-H = 0.96Å, common fixed
isotropic U = 0.06Å2. Final values are R = 5.88, wR =
8.58, GOF = 1.44, weight w–1 = s2 F + 0.0018 F2 second-ary
extinction correction c = 0.0021(5), residual electron den-sity:
0.36/ – 0.29 e/Å–3.
Acknowledgments
The authors are grateful to PREBELAC — The New York
Botanical Garden and DGAPA-UNAM-(IN214996) for fi-nancing
this project. We are grateful to I. Chavez, W. Matus,
B. Quiroz, and L. Velasco for preliminary analysis. We
thank M. A. Villavicencio and B.E. Pérez Escandón for per-forming
the insecticidal assays.
References
1. P.C Standley and J.A. Steyermark. Hippocrateaceae in flora of
Guatemala. Fieldiana Bot. 24, 218 (1949).
2. J.C. Soto-Nuñez and M. Sousa. Plantas Medicinales de la
Cuenca del Río Balsas. Serie Cuadernos del Instituto de
Biología No. 25. Universidad Nacional Autónoma de México.
México (1995).
3. A.G. González, I.L. Bazzochi, A.G. Ravelo, and J.G. Luis.
Rev Latinoam. Quím. 20, 17 (1989).
4. H. Oikawa, K. Katayama, Y. Suzuki, and A. Ichihara. J. Chem.
Soc. Chem. Comm. 1321 (1995); D.H.R. Barton, K.
Nakanishi, and D. Meth-Cohn. Comprehensive natural prod-ucts
chemistry. Vol. 1, 1999. pp. 367–408; K. Katayama, T.
Kobayashi, H. Oikawa, M. Honma, and A. Ichitara. Biochim.
Biophys. Acta, 1384, 387 (1998); Y. Hano, T. Nomura, and S.
Ueda. J. Chem. Soc. Chem. Commun. 610 (1990); D.E. Cane
and L. Guanglin. J. Am. Chem. Soc. 117, 6633 (1995); D.J.
Witter and J.C. Vederas. J. Org. Chem. 61, 2613 (1996); H.
Oikawa, T. Kobayashi, K. Katayama, Y. Suzuki, and A.
Ichihara. J. Org. Chem. 63, 8748 (1998); H. Oikawa, T.
Yokota, T. Abe, A. Ichihara, S. Sakamora, Y. Yoshizawa, and
J.C. Vedeyas. J. Chem. Soc. Chem. Commun. 1282 (1989).
5. S. Laschat. Angew. Chem. Int. Ed. Engl. 35(3), 289 (1996).
6. M. Rance, O.W. Sorensen, G. Bodenhausen, G. Wagner, R.R.
Ernst, and M. Rance. J. Magn. Reson. 74, 557 (1987).
7. G. Bodenhausen and D.J. Ruben. Chem. Phys. Lett. 69, 185
(1980).
8. K. Wuthrich. Biochem. Biophys. Res. Commun. 117, 479
(1983).
9. G. Wider and K. Wuthrich. J. Magn. Reson. 102, 239 (1993).
10. L. Lerner and A. Bax. J. Magn. Reson. 69, 375 (1986).
11. A. Bax and M. Summers. J. Am. Chem. Soc. 108, 2093
(1986).
Fig. 4. X-ray of celastroidine B (2).
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.

8. This article has been cited by:
1. Wendy Itzel Escobedo Hinojosa, Macdiel Acevedo Quiróz, Irma Romero Álvarez, Patricia Escobar Castañeda, María Luisa
Villarreal, Alexandre Cardoso Taketa. 2014. Anti-Helicobacter pylori, gastroprotective, anti-inflammatory, and cytotoxic activities
of methanolic extracts of five different populations of Hippocratea celastroides collected in Mexico. Journal of Ethnopharmacology
155, 1156-1163. [CrossRef]
2. Cássia G. Magalhães, Grácia D. de Fátima Silva, Lucienir P. Duarte, Isabel L. Bazzocchi, Antonio J. Diaz, Laila Moujir, Manuel
R. López, Rute C. Figueiredo, Sidney A. Vieira Filho. 2013. Salicassin, an Unprecedented ChalconeDiterpene Adduct and a
Quinone Methide Triterpenoid from Maytenus salicifolia. Helvetica Chimica Acta 96:10.1002/hlca.v96.6, 1046-1054. [CrossRef]
3. Marvin J. Núñez, María L. Kennedy, Ignacio A. Jiménez, Isabel L. Bazzocchi. 2011. Uragogin and blepharodin, unprecedented
hetero-Diels–Alder adducts from Celastraceae species. Tetrahedron 67, 3030-3033. [CrossRef]
Can. J. Chem. Downloaded from www.nrcresearchpress.com by UNAM PE8 on 09/05/14
For personal use only.