Synthesis and structure-activity relationship studies of cytotoxic ester and ether anhydrovinblastine derivatives

Article abstract of DOI:10.1021/np800284h

Two new series of 3-demethoxycarbonyl-3-ester and 3-demethoxycarbonyl-3- ether methyl anhydrovinblastine derivatives were designed, synthesized, and evaluated for their inhibitory activities against human non-small-cell lung cancer (A549) and cervical epi

Full text of DOI:10.1021/np800284h

J. Nat. Prod. 2008, 71, 1669–1676
1669
Synthesis and Structure-Activity Relationship Studies of Cytotoxic Ester and Ether
Anhydrovinblastine Derivatives
Han-Kun Zhang,†,‡ Yong Shao,†,‡ Hong Ding,§ and Li-Hong Hu*,†
Shanghai Research Center for the Modernization of Traditional Chinese Medicine, Shanghai Institute of Materia Medica, Chinese Academy of
Sciences, Shanghai 201203, People’s Republic of China, and Department of Molecular Pharmacology, Shanghai Institute of Materia Medica,
Chinese Academy of Sciences, Shanghai 201203, People’s Republic of China
ReceiVed May 9, 2008
Two new series of 3-demethoxycarbonyl-3-ester and 3-demethoxycarbonyl-3-ether methyl anhydrovinblastine derivatives
were designed, synthesized, and evaluated for their inhibitory activities against human non-small-cell lung cancer (A549)
and cervical epithelial adenocarcinoma (HeLa) cell lines. Ester anhydrovinblastine derivatives exhibited potent cytotoxicity,
whereas the ether analogues were much less active. The size of the introduced substituents was the foremost factor in
determining the resultant cytotoxic activity. Compound 12b showed a similar cytotoxic potency to the positive control,
anhydrovinblastine (1a).
Vinca (Catharanthus) alkaloids are used widely in human cancer
chemotherapy.1 The discovery of the antitumor properties of these
compounds was followed by extensive chemical research in this
area with the aim of discovering new bisindole alkaloids with
superior therapeutic activity. Anhydrovinblastine (1a)2 is a new
semisynthetic alkaloid that differs from vinblastine (1b) in having
a 3′,4′-double bond in the catharanthine moiety, a property it shares
with vinorelbine (1c).3 Compound 1a was found to be more active
than 1b and 1c against human tumor xenografts of H460 non-small-
cell lung cancer and of C4 cervical carcinoma in nude mice at
equitoxic doses.2 The improved efficacy resulted from a combina-
tion of increased antitumor potency and the ability to administer
increased doses of 1a compared to 1c.
also produced and tested in order to gain a better understanding of
the SAR of oxygen-linked analogues at C-22 of compound 1a.
Results and Discussion
The synthetic strategy that allowed the preparation of anhy-
drovinblastine derivatives utilized the modified Polonovski-Potier
reaction8 as a key step to form dimer vinca alkaloids. Vindoline
(2), the major alkaloid in whole plants of Catharanthus roseus, is
readily obtained and so was chosen as the starting material. A total
of 18 semisynthelic anhydrovinblastine derivatives (5b-22b) were
prepared, as outlined in Scheme 1. The crucial intermediate triol 4
was prepared by reduction of 2 with LiAlH4. The triol 4 was stirred
with BtCOR1 and sodium hydride in anhydrous THF at room
temperature, then acetylated at C-4 OH to furnish compounds
5a-17a, which were subsequently coupled with 3 to produce ester
anhydrovinblastine derivatives (5b-17b). The BtCOR1 derivatives
could be prepared using a different acyl chloride or acid anhydride
reacted with benzotriazole in the presence of diisopropylethylamine
(DIPEA) in dichloromethane (DCM). By replacing the BtCOR1 with
different alkyl halides, the triol 4 was treated with diverse alkyl
bromides in THF including 50% sodium hydroxide solution at 60
°C. This was acetylated at the C-4 OH to furnish compounds
18a-22a, which were then coupled with catharanthine (3) to
produce the ether anhydrovinblastine derivatives (18b-22b). Alkyl
bromides were obtained from commercial suppliers.
The cytotoxic activities of all these anhydrovinblastine derivatives
were evaluated against human non-small-cell lung cancer (A549)
and cervical epithelial adenocarcinoma (HeLa) cell lines using a
sulforhodamine B (SRB) assay,9 employing 1a as positive control.
The IC50 values for the inhibition of proliferation of the A549 and
HeLa cell lines are shown in Table 1. Among six alkyl-substituted
ester analogues (5b-10b), a marked loss of cytotoxicity was
observed against both cell lines with the increasing size of the alkyl
groups. Similar conclusions also could be obtained from ester
analogues substituted with aromatic groups (11b and 12b). The
benzyl ester 11b (IC50 ) 67.4, 272.0 nM), with an aromatic group
Functional group reversal is a common strategy in medicinal
chemistry.4,5 In previous investigations of the structural require-
ments for cytotoxic activity of 1a,6 an acetyloxymethyl group was
introduced instead of methyl carboxylate at the C-22 position to
afford a “reverse ester” derivative termed BM6 (5b).7 Although
its cytotoxic activity against a wide spectrum of tumor cell lines
decreased about 10-fold when compared with 1c, 5b showed
superior antitumor activities in vivo to 1c in preclinical tumor
models.2 Accordingly, in the present study, 3-demethoxycarbonyl-
3-ester methyl anhydrovinblastine derivatives, with inverted ester
groups at the C-22 position of 1a, were designed, synthesized, and
tested for cytotoxic activity against the A549 and HeLa cell lines.
In addition, 3-demethoxycarbonyl-3-methyl ether derivatives were
having one more carbon atom than the phenyl ester 12b (IC50
)
25.4, 35.6 nM), exhibited decreased cytotoxicity against both cell
lines. This showed that a phenyl group is more suitable than a
benzyl group to maintain activity. Introduction of electron-donating
(OMe) or electron-withdrawing groups (Cl and NO2) in the phenyl
group greatly decreased the cytotoxicity against the HeLa cell line.
However, the derivatives with electron-donating groups at the C-2
or C-4 position of the phenyl group (13b, 14b) exhibited better
cytotoxic activities against the A549 cell line than 1a. 2-Substituted
* To whom correspondence should be addressed. Tel: 86-21-50272221.
Fax: 86-21-50272221. E-mail: simmhulh@mail.shcnc.ac.cn.
† Shanghai Research Center for the Modernization of Traditional Chinese
Medicine.
‡ These two authors contributed equally to this work.
§ Shanghai Institute of Materia Medica.
10.1021/np800284h CCC: $40.75
2008 American Chemical Society and American Society of Pharmacognosy
Published on Web 09/04/2008

1670 Journal of Natural Products, 2008, Vol. 71, No. 10
Zhang et al.
Scheme 1a
a Reagents and conditions: (a) LiAlH4, THF, 0 °C to rt, 4 h, 98%; (b) BtCOR1, NaH, THF, rt, 3 h; (c) R2Br, THF, 50% NaOH-H2O, Bu4N+I-, 60 °C, 6 h; (d) Ac2O,
pyridine; (e) (i) FeCl3, HCl-H2O buffer (pH ) 2), 8 h; (ii) NaBH4, NH4OH, 0 °C, 15 min; (f) DCM, Et3N, rt, 3 h.
mentioned, all chemicals and materials were used as received from
commercial suppliers without further purification. Tetrahydrofuran
(THF) was distilled from sodium benzophenone under nitrogen.
Dichloromethane (DCM) was distilled from calcium hydride. Com-
pounds 1a and 1c were purchased from Shanghai Kang’ai Biological
Products Company, Ltd.
phenyl esters showed higher activity than their 4-substituted
counterparts against the A549 cell line. Compared with other ester
derivatives, compound 12b exhibited the best cytotoxic activity
against both cell lines and showed an eqully cytotoxic potency to
the 1a.
As shown in Table 1, it was observed that the five ether
derivatives (18b-22b) were much less active than 1a. Thus,
introducing an ether group at C-22 of the vindoline moiety is
unsuitable for improving the cytotoxic activities of anhydrovin-
blastine derivatives. In comparison with 1a, these ether analogues
have a lack of a carbonyl group at C-22. As a hydrogen acceptor,
the carbonyl group appears to be important for maintaining the
cytotoxic potency.
In summary, the structure-activity relationships of two classes
of derivatives of anhydrovinblastine (1a) as cytotoxic agents have
been described. The size of the substituents at the C-22 position is
a crucial factor for improving cytotoxic activity. Ester anhydrovin-
blastine derivatives are more promising than ether derivatives, with
12b found to be equivalent in potency to 1a in the biological assays
used.
3,4,22-Triol-3-demethoxycarbonyl-3-hydroxymethyl-4-deacetylvin-
doline (4). To a suspension of LiAlH4 (114 mg, 3.00 mmol) in dry
THF (10 mL) at 0 °C was added slowly a solution of vindoline (486
mg, 1.00 mmol) in dry THF (10 mL). The reaction mixture was stirred
at room temperature for 4 h and then quenched cautiously by the
subsequent addition of water (114 µL), 15% NaOH(aq) (114 µL), and
water (342 µL). The resulting suspension was warmed to room
temperature and stirred for 10 min. The suspension was filtered through
a fritted funnel, and the filtrate was concentrated in vacuo to give a
crude triol. The product was used in the next step without purification.
[R]20D +45 (c 0.20, CHCl3); 1H NMR (400 MHz, CDCl3) δ 8.73 (1H,
brs), 6.82 (1H, d, J ) 8.0 Hz), 6.30 (1H, dd, J ) 8.0, 2.4 Hz), 6.12
(1H, d, J ) 2.4 Hz), 5.88 (1H, dd, J ) 10.0, 4.8 Hz), 5.60 (1H, d, J )
10.0 Hz), 3.93 (1H, d, J ) 11.2 Hz), 3.78 (3H, s), 3.72 (1H, d, J )
11.2 Hz), 3.52 (2H, s), 3.45 (1H, dd, J ) 15.6, 4.4 Hz), 3.35 (1H, td,
J ) 9.2, 4.4 Hz), 3.00 (3H, s), 2.83 (1H, dt, J ) 15.6, 2.0 Hz), 2.57
(1H, s), 2.53-2.50 (2H, m), 2.25-2.16 (3H, m), 1.36-1.31 (1H, m),
0.94-0.88 (1H, m), 0.62 (3H, t, J ) 7.6 Hz); 13C NMR (75 MHz,
CDCl3) δ 160.9 (C), 154.6 (C), 130.8 (CH), 126.5 (C), 124.3 (CH),
122.9 (CH), 104.6 (CH), 96.3 (CH), 81.0 (CH), 77.4 (CH), 75.2 (C),
68.3 (CH), 65.7 (CH2), 55.4 (OCH3), 51.8 (C), 51.7 (CH2), 51.3 (CH2),
44.8 (CH2), 43.5 (C), 40.4 (CH3), 32.5 (CH2), 7.9 (CH3); EIMS m/z
386 [M]+ 368, 355, 297, 212, 188, 174, 162, 135, 93.
Experimental Section
General Experimental Procedures. Optical rotations were deter-
mined on a Perkin-Elmer 341 polarimeter. IR spectra were recorded
on a Perkin-Elmer 577 spectrometer. NMR spectra were recorded on
a Varian Mercury-VX300 Fourier transform spectrometer or a Bruker
AM-400 spectrometer. The chemical shifts are reported in (ppm) using
the δ 7.26 signal of CDCl3 (1H NMR) and the δ 77.23 signal of CDCl3
(13C NMR) as internal standards. EIMS were obtained on a Shimadzu
GCMS-QP5050A spectrometer. ESIMS were run on a Bruker Esquire
3000 plus spectrometer in MeOH. Thin-layer chromatographic (TLC)
plates (silica gel 60 GF, with glass support) from Yantai Jiangyou
Company were used for monitoring the progress of a reaction and
visualized with 254 nm UV light and/or sprayed with a 10% solution
of ceric ammonium sulfate (CAS) in phosphoric acid. Unless otherwise
General Procedure for the Preparation of 5a-17a. A solution of
the benzotriazole (2 mmol) in dry CH2Cl2 (10 mL) was treated with
diisopropylethylamine (0.43 mL, 2.5 mmol) followed by the dropwise
addition of a solution of a different acyl chloride or acid anhydride
(2.2 mmol) in CH2Cl2 (2 mL) at 0 °C. This was allowed to warm to
room temperature and stirred a further 2 h. Then, the reaction mixture
was quenched with H2O (20 mL) and extracted with EtOAc (2 × 20
mL). The combined organic phase was washed with brine (10 mL)

Cytotoxic Ester AnhydroVinblastine DeriVatiVes
Journal of Natural Products, 2008, Vol. 71, No. 10 1671
130.2 (CH), 125.9 (C), 124.3 (CH), 122.8 (CH), 104.9 (CH), 96.4 (CH),
81.6 (CH), 76.8 (CH), 76.2 (C), 67.8 (CH), 66.9 (CH2), 55.4 (OCH3),
52.2 (C), 51.8 (CH2), 50.9 (CH2), 44.7 (CH2), 42.7 (C), 40.1 (CH3),
31.5 (CH2), 21.2 (CH3), 21.1 (CH3), 7.6 (CH3); ESIMS m/z 471.3 [M
+ 1]+.
Table 1. Cytotoxic Activity of Anhydrovinblastine (1a)
Analoguesa
3-Demethoxycarbonyl-3-(ethylcarbonyloxy)methylvindoline (6a).
Compound 6a was prepared using propionyl chloride as starting
1
material. Yield: 55%; H NMR (300 MHz, CDCl3) δ 8.96 (1H, brs),
6.89 (1H, d, J ) 8.1 Hz), 6.31 (1H, d, J ) 8.1 Hz), 6.14 (1H, s), 5.87
(1H, dd, J ) 10.2, 3.6 Hz), 5.37 (1H, d, J ) 10.2 Hz), 5.04 (1H, s),
4.23 (1H, d, J ) 11.4 Hz), 4.03 (1H, d, J ) 11.4 Hz), 3.80 (3H, s),
3.64 (1H, s), 3.46 (2H, m), 2.87 (3H, s), 2.81 (1H, d, J ) 15.9 Hz),
2.64 (1H, s), 2.51 (1H, m), 2.44 (2H, q, J ) 7.2 Hz), 2.29 (2H, m),
2.15 (3H, s), 1.32 (1H, m), 1.16 (3H, t, J ) 7.2 Hz), 1.03 (1H, m),
0.53 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ 173.9 (C),
170.5 (C), 160.8 (C), 154.2 (C), 129.9 (CH), 125.7 (C), 124.0 (CH),
122.5 (CH), 104.6 (CH), 96.1 (CH), 81.4 (CH), 76.6 (CH), 76.0 (C),
67.6 (CH), 66.3 (CH2), 55.1 (OCH3), 51.9 (C), 51.6 (CH2), 50.6 (CH2),
44.4 (CH2), 42.4 (C), 39.7 (CH3), 31.3 (CH2), 27.3 (CH2), 20.7 (CH3),
9.0 (CH3), 7.4 (CH3); ESIMS m/z 485.3 [M + 1]+.
3-Demethoxycarbonyl-3-(isopropylcarbonyloxy)methylvin-
doline (7a). Compound 7a was prepared using isobutyryl chloride as
starting material. Yield: 58%; 1H NMR (300 MHz, CDCl3) δ 8.83 (1H,
brs), 6.89 (1H, d, J ) 8.1 Hz), 6.31 (1H, dd, J ) 8.1, 2.4 Hz), 6.13
(1H, d, J ) 2.4 Hz), 5.87 (1H, dd, J ) 10.2, 3.6 Hz), 5.36 (1H, d, J )
10.2 Hz), 5.03 (1H, s), 4.25 (1H, d, J ) 11.7 Hz), 4.01 (1H, d, J )
11.7 Hz), 3.79 (3H, s), 3.62 (1H, s), 3.45 (2H, m), 2.88 (3H, s), 2.80
(1H, d, J ) 15.9 Hz), 2.69 (1H, m), 2.62 (1H, s), 2.51 (1H, m), 2.29
(2H, m), 2.13 (3H, s), 1.32 (1H, m), 1.19 (6H, dd, J ) 6.6, 1.2 Hz),
1.03 (1H, m), 0.52 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ
176.3 (C), 170.4 (C), 160.8 (C), 154.1 (C), 129.9 (CH), 125.7 (C),
123.9 (CH), 122.5 (CH), 104.5 (CH), 96.0 (CH), 81.4 (CH), 76.4 (CH),
76.0 (C), 67.6 (CH), 65.9 (CH2), 55.0 (OCH3), 51.8 (C), 51.6 (CH2),
50.6 (CH2), 44.4 (CH2), 42.4 (C), 39.6 (CH3), 33.6 (CH), 31.2 (CH2),
20.6 (CH3), 18.9 (CH3), 18.7 (CH3), 7.3 (CH3); ESIMS m/z 499.2 [M
+ 1]+.
3-Demethoxycarbonyl-3-(tert-butylcarbonyloxy)methylvindo-
line (8a). Compound 8a was prepared using pivaloyl chloride as starting
1
material. Yield: 56%; H NMR (300 MHz, CDCl3) δ 9.02 (1H, brs),
6.89 (1H, d, J ) 8.1 Hz), 6.30 (1H, d, J ) 8.1 Hz), 6.12 (1H, s), 5.84
(1H, dd, J ) 9.3, 3.3 Hz), 5.33 (1H, d, J ) 9.3 Hz), 5.01 (1H, s), 4.32
(1H, d, J ) 11.4 Hz), 3.94 (1H, d, J ) 11.4 Hz), 3.79 (3H, s), 3.60
(1H, s), 3.48 (2H, m), 2.89 (3H, s), 2.81 (1H, m), 2.63 (1H, s), 2.50
(1H, m), 2.25 (1H, m), 2.16 (1H, m), 2.06 (3H, s), 1.27 (1H, m), 1.24
(9H, s), 0.96 (1H, m), 0.50 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz,
CDCl3) δ 171.0 (C), 170.8 (C), 161.0 (C), 154.4 (C), 130.2 (CH), 125.9
(C), 124.3 (CH), 122.8 (CH), 104.9 (CH), 96.4 (CH), 81.6 (CH), 76.8
(CH), 76.2 (C), 67.8 (CH), 66.9 (CH2), 55.4 (OCH3), 52.2 (C), 51.8
(CH2), 50.9 (CH2), 44.9 (CH2), 42.7 (C), 40.1 (CH3), 38.9 (C), 31.5
(CH2), 27.7 (3CH3), 21.2 (CH3), 7.6 (CH3); ESIMS m/z 513.3 [M +
1]+.
a Ditartrate of each compound used for bioassay.
and dried over anhydrous Na2SO4. Concentration gave a BtCOR1
product, which was used in the next step without purification.
To a solution of 4 (1 mmol) and BtCOR1 (1.1 mmol) in anhydrous
THF (10 mL) was added sodium hydride (60%, 1 mmol) under N2.
After being stirred at room temperature for 3 h, the reaction mixture
was quenched with H2O (20 mL) and extracted with CH2Cl2 (2 × 25
mL). The combined organic extracts were washed with brine and dried
over anhydrous Na2SO4. Concentration followed by purification by flash
chromatography (4:1, hexanes-acetone) provided a crude product,
which was added to pyridine (1.0 mL) and Ac2O (1.0 mL) at room
temperature. After stirring the reaction mixture for 8 h, saturated
NaHCO3 (5 mL) and EtOAc (20 mL) were added, and the organic
phase was washed with H2O (3 × 10 mL) and brine (10 mL), dried,
concentrated,andpurifiedbyflashchromatography(6:1,hexanes-acetone)
to provide a white solid (5a-17a).
3-Demethoxycarbonyl-3-(isobutylcarbonyloxy)methylvindoline (9a).
Compound 9a was prepared using isovaleryl chloride as starting
1
material. Yield: 56%; H NMR (300 MHz, CDCl3) δ 8.83 (1H, brs),
6.89 (1H, d, J ) 8.1 Hz), 6.31 (1H, dd, J ) 8.1, 2.4 Hz), 6.13 (1H, d,
J ) 2.1 Hz), 5.88 (1H, dd, J ) 10.5, 3.6 Hz), 5.37 (1H, d, J ) 10.5
Hz), 5.03 (1H, s), 4.26 (1H, d, J ) 11.4 Hz), 4.00 (1H, d, J ) 11.4
Hz), 3.80 (3H, s), 3.64 (1H, s), 3.48 (2H, m), 2.89 (3H, s), 2.81 (1H,
d, J ) 15.9 Hz), 2.64 (1H, s), 2.51 (1H, m), 2.29 (4H, m), 2.15 (3H,
s), 1.32 (1H, m), 1.03 (1H, m), 0.97 (6H, d, J ) 6.6 Hz), 0.89 (1H,
m), 0.52 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ 172.4 (C),
170.5 (C), 160.8 (C), 154.1 (C), 129.9 (CH), 125.7 (C), 123.9 (CH),
122.5 (CH), 104.6 (CH), 96.1 (CH), 81.2 (CH), 76.5 (CH), 76.0 (C),
67.6 (CH), 66.0 (CH2), 55.0 (OCH3), 51.8 (C), 51.5 (CH2), 50.6 (CH2),
44.4 (CH2), 43.1 (CH2), 42.4 (C), 39.7 (CH3), 31.3 (CH2), 25.3 (CH),
22.2 (2CH3), 20.7 (CH3), 7.3 (CH3); ESIMS m/z 513.3 [M + 1]+.
3-Demethoxycarbonyl-3-(cyclopropylcarbonyloxy)methylvindo-
line (10a). Compound 10a was prepared using cyclopropanecarbonyl
chloride as starting material. Yield: 52%; 1H NMR (300 MHz, CDCl3)
δ 8.95 (1H, brs), 6.90 (1H, d, J ) 8.1 Hz), 6.32 (1H, dd, J ) 8.1, 2.4
Hz), 6.14 (1H, d, J ) 2.4 Hz), 5.89 (1H, dd, J ) 10.2, 3.6 Hz), 5.38
(1H, d, J ) 10.2 Hz), 5.04 (1H, s), 4.24 (1H, d, J ) 11.7 Hz), 4.03
(1H, d, J ) 11.7 Hz), 3.80 (3H, s), 3.68 (1H, s), 3.45 (2H, m), 2.90
(3H, s), 2.81 (1H, d, J ) 14.1 Hz), 2.65 (1H, s), 2.50 (1H, m), 2.51
3-Demethoxycarbonyl-3-(methylcarbonyloxy)methylvindoline (5a).
Compound 5a was prepared using acetate anhydride as starting material.
1
Yield: 85%; H NMR (300 MHz, CDCl3) δ 9.02 (1H, brs), 6.86 (1H,
d, J ) 8.1 Hz), 6.28 (1H, d, J ) 8.1 Hz), 6.11 (1H, s), 5.87 (1H, dd,
J ) 9.9, 3.3 Hz), 5.35 (1H, d, J ) 9.9 Hz), 5.00 (1H, s), 4.08 (2H, d,
J ) 10.8 Hz), 3.76 (3H, s), 3.62 (1H, s), 3.40 (2H, m), 2.84 (3H, s),
2.81 (1H, m), 2.61 (1H, s), 2.47 (1H, m), 2.25 (1H, m), 2.16 (1H, m),
2.11 (6H, s), 1.27 (1H, m), 0.96 (1H, m), 0.49 (3H, t, J ) 7.2 Hz); 13
C
NMR (75 MHz, CDCl3) δ 170.9 (C), 170.8 (C), 161.1 (C), 154.4 (C),

1672 Journal of Natural Products, 2008, Vol. 71, No. 10
Zhang et al.
(1H, m), 2.30 (2H, m), 2.14 (3H, s), 1.74 (1H, m), 1.32 (2H, m), 1.01
(2H, m), 0.86 (2H, m), 0.53 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz,
CDCl3) δ 174.5 (C), 170.6 (C), 160.9 (C), 154.3 (C), 130.0 (CH), 125.7
(C), 124.1 (CH), 122.6 (CH), 104.7 (CH), 96.2 (CH), 81.5 (CH), 76.7
(CH), 76.1 (C), 67.6 (CH), 66.6 (CH2), 55.2 (OCH3), 52.0 (C), 51.7
(CH2), 50.7 (CH2), 44.6 (CH2), 42.5 (C), 39.9 (CH3), 31.3 (CH2), 20.8
(CH3), 12.7 (CH), 8.5 (2CH2), 7.4 (CH3); ESIMS m/z 497.3 [M + 1]+.
3-Demethoxycarbonyl-3-(benzylcarbonyloxy)methylvindoline (11a).
Compound 11a was prepared using phenylacetyl chloride as starting
δ 8.79 (1H, brs), 7.79 (1H, d, J ) 7.2 Hz), 7.29 (2H, m), 7.20 (1H,
m), 6.79 (1H, t, J ) 8.1 Hz), 6.20 (1H, d, J ) 8.1 Hz), 6.02 (1H, s),
5.78 (1H, dd, J ) 10.5, 3.6 Hz), 5.29 (1H, d, J ) 10.5 Hz), 5.01 (1H,
s), 4.44(1H, d, J ) 11.4 Hz), 4.16 (1H, d, J ) 11.4 Hz), 3.63 (3H, s),
3.61 (1H, s), 3.37-3.24 (2H, m), 2.89 (3H, s), 2.69 (1H, d, J ) 15.9
Hz), 2.54 (1H, s), 2.39 (1H, m), 2.16 (2H, m), 2.01 (3H, s), 1.25 (1H,
m), 0.95 (1H, m), 0.43 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3)
δ 170.4 (C), 164.8 (C), 160.8 (C), 154.0 (C), 133.3 (C), 132.3 (CH),
131.3 (CH), 130.7 (CH), 129.8 (CH), 129.7 (C), 126.4 (CH), 125.6
(C), 123.9 (CH), 122.5 (CH), 104.6 (CH), 96.0 (CH), 81.4 (CH), 76.3
(CH), 76.0 (C), 67.5 (CH), 67.0 (CH2), 54.9 (OCH3), 51.8 (C), 51.5
(CH2), 50.6 (CH2), 44.4 (CH2), 42.4 (C), 39.8 (CH3), 31.2 (CH2), 20.6
(CH3), 7.3 (CH3); ESIMS m/z 567.3 [M + 1]+.
3-Demethoxycarbonyl-3-(4-chlorophenylcarbonyloxy)meth-
ylvindoline (16a). Compound 16a was prepared using 4-chlorobenzoyl
chloride as starting material. Yield: 60%; 1H NMR (300 MHz, CDCl3)
δ 8.85 (1H, brs), 7.92 (2H, d, J ) 7.2 Hz), 7.29 (2H, d, J ) 7.2 Hz),
6.82 (1H, d, J ) 8.4 Hz), 6.22 (1H, d, J ) 8.4 Hz), 6.02 (1H, s), 5.78
(1H, dd, J ) 10.5, 3.6 Hz), 5.30 (1H, d, J ) 10.5 Hz), 5.04 (1H, s),
4.47(1H, d, J ) 11.4 Hz), 4.13 (1H, d, J ) 11.4 Hz), 3.65 (3H, s),
3.61 (1H, s), 3.38-3.27 (2H, m), 2.82 (3H, s), 2.71 (1H, d, J ) 15.9
Hz), 2.59 (1H, s), 2.43 (1H, m), 2.19 (2H, m), 2.02 (3H, s), 1.26 (1H,
m), 0.97 (1H, m), 0.46 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3)
δ 170.4 (C), 164.9 (C), 160.8 (C), 154.0 (C), 139.0 (C), 130.8 (2 CH),
129.9 (CH), 128.4 (2 CH), 128.4 (C), 125.5 (C), 124.0 (CH), 122.5
(CH), 104.5 (CH), 96.0 (CH), 82.0 (CH), 76.3 (CH), 76.0 (C), 67.4
(CH), 67.0 (CH2), 55.0 (OCH3), 52.0 (C), 51.4 (CH2), 50.7 (CH2), 44.5
(CH2), 42.4 (C), 39.8 (CH3), 31.2 (CH2), 20.6 (CH3), 7.3 (CH3); ESIMS
m/z 567.3 [M + 1]+.
1
material. Yield: 61%; H NMR (300 MHz, CDCl3) δ 9.02 (1H, brs),
7.22 (5H, m), 6.86 (1H, d, J ) 8.4 Hz), 6.29 (1H, d, J ) 8.4 Hz), 6.05
(1H, s), 5.87 (1H, dd, J ) 10.2, 3.9 Hz), 5.37 (1H, d, J ) 10.2 Hz),
4.99 (1H, s), 4.30 (1H, d, J ) 11.1 Hz), 3.95 (1H, d, J ) 11.1 Hz),
3.78 (3H, s), 3.72 (2H, s), 3.48 (2H, m), 2.81 (1H, m), 2.63 (1H, s),
2.56 (3H, s), 2.47 (1H, m), 2.25 (1H, m), 2.16 (2H, m), 2.12 (3H, s),
1.27 (1H, m), 0.96 (1H, m), 0.48 (3H, t, J ) 7.2 Hz); 13C NMR (75
MHz, CDCl3) δ 171.0 (C), 170.8 (C), 161.0 (C), 154.3 (C), 135.4 (C),
130.4 (CH), 129.6 (2 CH), 129.0 (2 CH), 127.2 (CH), 125.9 (C), 124.3
(CH), 122.8 (CH), 105.5 (CH), 97.4 (CH), 82.9 (CH), 76.5 (C), 75.8
(CH), 67.1 (CH), 66.9 (CH2), 55.5 (OCH3), 52.3 (C), 51.5 (CH2), 50.9
(CH2), 45.0 (CH2), 43.6 (CH2), 42.9 (C), 41.0 (CH3), 31.3 (CH2), 21.1
(CH3), 7.6 (CH3); ESIMS m/z 547.3 [M + 1]+.
3-Demethoxycarbonyl-3-(phenylcarbonyloxy)methylvindoline (12a).
Compound 12a was prepared using benzoyl chloride as starting material.
1
Yield: 63%; H NMR (300 MHz, CDCl3) δ 8.94 (1H, brs), 8.08 (2H,
d, J ) 7.5 Hz), 7.56 (1H, t, J ) 7.5 Hz), 7.44 (2H, t, J ) 7.5 Hz), 6.91
(1H, d, J ) 8.4 Hz), 6.32 (1H, d, J ) 8.4 Hz), 6.11 (1H, s), 5.89 (1H,
dd, J ) 10.2, 3.9 Hz), 5.39 (1H, d, J ) 10.2 Hz), 5.13 (1H, s), 4.57(1H,
d, J ) 11.4 Hz), 4.20 (1H, d, J ) 11.4 Hz), 3.79 (3H, s), 3.74 (1H, s),
3.51-3.38 (2H, m), 2.92 (3H, s), 2.82 (1H, d, J ) 15.6 Hz), 2.67 (1H,
s), 2.51 (1H, m), 2.31 (2H, m), 2.14 (3H, s), 1.32 (1H, m), 0.79 (1H,
m), 0.54 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ 171.3 (C),
165.7 (C), 160.8 (C), 154.0 (C), 132.7 (CH), 129.9 (CH), 129.9 (C),
129.4 (2 CH), 128.1 (2 CH), 125.5 (C), 123.9 (CH), 122.5 (CH), 104.5
(CH), 96.0 (CH), 82.8 (CH), 76.4 (CH), 76.1 (C), 67.4 (CH), 66.5
(CH2), 54.9 (OCH3), 52.3 (C), 51.4 (CH2), 50.5 (CH2), 44.5 (CH2),
42.4 (C), 39.7 (CH3), 31.2 (CH2), 20.6 (CH3), 7.3 (CH3); ESIMS m/z
533.4 [M + 1]+.
3-Demethoxycarbonyl-3-(4-nitrophenylcarbonyloxy)meth-
ylvindoline (17a). Compound 17a was prepared using 4-nitrobenzoyl
chloride as starting material. Yield: 60%; 1H NMR (300 MHz, CDCl3)
δ 8.88 (1H, brs), 8.14 (4H, s), 6.83 (1H, d, J ) 8.1 Hz), 6.22 (1H, d,
J ) 8.4 Hz), 6.02 (1H, s), 5.80 (1H, dd, J ) 9.9, 3.6 Hz), 5.31 (1H, d,
J ) 9.9 Hz), 5.03 (1H, s), 4.51 (1H, d, J ) 11.1 Hz), 4.18 (1H, d, J )
11.1 Hz), 3.65 (3H, s), 3.61 (1H, s), 3.41-3.28 (2H, m), 2.84 (3H, s),
2.74 (1H, d, J ) 16.2 Hz), 2.61 (1H, s), 2.43 (1H, m), 2.20 (2H, m),
2.02 (3H, s), 1.23 (1H, m), 0.95 (1H, m), 0.45 (3H, t, J ) 7.2 Hz); 13
C
3-Demethoxycarbonyl-3-(2-methoxylphenylcarbonyloxy)meth-
ylvindoline (13a). Compound 13a was prepared using 2-methoxyben-
NMR (75 MHz, CDCl3) δ 170.4 (C), 164.0 (C), 160.8 (C), 154.0 (C),
150.2 (C), 135.2 (C), 130.5 (2 CH), 129.8 (CH), 125.4 (C), 124.0 (CH),
123.3 (2 CH), 122.5 (CH), 104.6 (CH), 96.1 (CH), 82.0 (CH), 76.2
(CH), 76.0 (C), 67.3 (CH), 67.2 (CH2), 55.0 (OCH3), 52.0 (C), 51.3
(CH2), 50.5 (CH2), 44.4 (CH2), 42.4 (C), 39.9 (CH3), 31.2 (CH2), 20.6
(CH3), 7.2 (CH3); ESIMS m/z 578.3 [M + 1]+.
1
zoyl chloride as starting material. Yield: 63%; H NMR (300 MHz,
CDCl3) δ 8.86 (1H, brs), 7.86 (1H, d, J ) 7.5 Hz), 7.47 (1H, t, J ) 7.5
Hz), 6.97 (1H, t, J ) 7.5 Hz), 6.97 (1H, d, J ) 7.5 Hz), 6.90 (1H, d,
J ) 8.4 Hz), 6.31 (1H, d, J ) 8.4 Hz), 6.12 (1H, s), 5.88 (1H, dd, J )
10.5, 3.6 Hz), 5.38 (1H, d, J ) 10.5 Hz), 5.12 (1H, s), 4.49 (1H, d, J
) 11.4 Hz), 4.19 (1H, d, J ) 11.4 Hz), 3.87 (3H, s), 3.79 (3H, s), 3.74
(1H, s), 3.50-3.36 (2H, m), 2.95 (3H, s), 2.80 (1H, d, J ) 15.6 Hz),
2.66 (1H, s), 2.54 (1H, m), 2.31 (2H, m), 2.14 (3H, s), 1.36 (1H, m),
1.03 (1H, m), 0.53 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ
170.2 (C), 165.5 (C), 160.6 (C), 158.7 (C), 154.0 (C), 133.1 (CH),
131.4 (CH), 129.6 (CH), 125.5 (C), 123.7 (CH), 122.3 (CH), 119.6
(CH), 119.5 (C), 111.5 (CH), 104.2 (CH), 95.7 (CH), 81.0 (CH), 76.3
(CH), 75.9 (C), 67.4 (CH), 66.3 (CH2), 55.2 (OCH3), 54.8 (OCH3),
51.6 (C), 51.3 (CH2), 50.3 (CH2), 44.2 (CH2), 42.2 (C), 39.1 (CH3),
31.1 (CH2), 20.4 (CH3), 7.1 (CH3); ESIMS m/z 563.3 [M + 1]+.
3-Demethoxycarbonyl-3-(4-methoxylphenylcarbonyloxy)meth-
ylvindoline (14a). Compound 14a was prepared using 4-methoxyben-
General Procedure for the Preparation of 18a-22a. A solution
of compound 4 (1 mmol) in THF (10 mL) was added to 50% sodium
hydroxide solution (2 g) and n-Bu4N+I- (36.9 mg, 0.1 mmol). After
being stirred at 60 °C for 0.5 h, diverse alkyl halides (2 mmol) were
added slowly. The reaction mixture continued stirring for 6 h and was
then cooled to room temperature. The mixture was quenched with H2O
(20 mL) and extracted with CH2Cl2 (2 × 25 mL). The combined organic
extracts were washed with brine and dried over anhydrous Na2SO4.
Concentration gave a residue that was added to pyridine (1.0 mL) and
Ac2O (1.0 mL) at room temperature. After stirring the reaction mixture
for 8 h, saturated NaHCO3 (5 mL) and EtOAc (20 mL) were added,
and the organic phase was washed with H2O (3 × 10 mL) and brine
(10 mL), dried, concentrated, and purified by flash chromatography
(6:1, hexanes-acetone) to provide a white solid (18a-22a).
1
zoyl chloride as starting material. Yield: 62%; H NMR (300 MHz,
CDCl3) δ 8.86 (1H, brs), 7.97 (1H, d, J ) 8.7 Hz), 6.84 (3H, d, J )
8.7 Hz), 6.24 (1H, d, J ) 8.7 Hz), 6.04 (1H, s), 5.81 (1H, dd, J )
10.5, 4.5 Hz), 5.32 (1H, d, J ) 10.5 Hz), 5.07 (1H, s), 4.46 (1H, d, J
) 11.7 Hz), 4.11 (1H, d, J ) 11.7 Hz), 3.74 (3H, s), 3.69 (3H, s), 3.66
(1H, s), 3.42-3.30 (2H, m), 2.84 (3H, s), 2.73 (1H, d, J ) 16.2 Hz),
2.60 (1H, s), 2.43 (1H, m), 2.24 (2H, m), 2.05 (3H, s), 1.28 (1H, m),
1.00 (1H, m), 0.48 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ
170.6 (C), 165.7 (C), 163.2 (C), 160.9 (C), 154.2 (C), 131.5 (2 CH),
130.5 (CH), 125.7 (C), 124.0 (CH), 122.6 (CH), 122.3 (C), 113.5 (2
CH), 104.5 (CH), 96.0 (CH), 82.0 (CH), 76.5 (CH), 76.2 (C), 67.5
(CH), 66.4 (CH2), 55.1 (2 OCH3), 52.0 (C), 51.5 (CH2), 50.5 (CH2),
44.6 (CH2), 42.6 (C), 39.7 (CH3), 31.3 (CH2), 20.7 (CH3), 7.4 (CH3);
ESIMS m/z 563.3 [M + 1]+.
3-Demethoxycarbonyl-3-(ethoxy)methylvindoline (18a). Com-
pound 18a was prepared using bromoethane as starting material. Yield:
1
58%; H NMR (300 MHz, CDCl3) δ 8.80 (1H, brs), 6.84 (1H, d, J )
8.1 Hz), 6.24 (1H, dd, J ) 8.1, 2.1 Hz), 6.08 (1H, d, J ) 2.1 Hz), 5.84
(1H, dd, J ) 10.2, 4.8 Hz), 5.37 (1H, d, J ) 10.2 Hz), 4.97 (1H, s),
3.76 (3H, s), 3.71 (1H, s), 2.93 (3H, s), 2.76 (1H, d, J ) 15.9 Hz),
2.58 (1H, s), 2.40 (1H, m), 2.11 (3H, s), 1.22 (1H, m), 1.20 (3H, t, J
) 7.2 Hz), 0.96 (1H, m), 0.50 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz,
CDCl3) δ 171.0 (C), 161.1 (C), 154.8 (C), 130.4 (CH), 126.2 (C), 124.2
(CH), 122.7 (CH), 104.3 (CH), 96.0 (CH), 80.9 (CH), 77.6 (C), 77.6
(CH), 72.7 (CH2), 68.0 (CH), 66.8 (CH2), 55.4 (OCH3), 52.0 (C), 52.0
(CH2), 50.9 (CH2), 44.8 (CH2), 42.6 (C), 39.1 (CH3), 31.7 (CH2), 21.1
(CH3), 15.1 (CH3), 7.6 (CH3); ESIMS m/z 457.3 [M + 1]+.
3-Demethoxycarbonyl-3-(2-chlorophenylcarbonyloxy)meth-
ylvindoline (15a). Compound 15a was prepared using 2-chlorobenzoyl
chloride as starting material. Yield: 63%; 1H NMR (300 MHz, CDCl3)
3-Demethoxycarbonyl-3-(allyloxy)methylvindoline (19a). Com-
pound 19a was prepared using allyl bromide as starting material. Yield:
1
61%; H NMR (300 MHz, CDCl3) δ 8.80 (1H, brs), 6.79 (1H, d, J )

Cytotoxic Ester AnhydroVinblastine DeriVatiVes
Journal of Natural Products, 2008, Vol. 71, No. 10 1673
8.1 Hz), 6.19 (1H, dd, J ) 8.1, 2.1 Hz), 6.03 (1H, d, J ) 2.1 Hz), 5.85
(1H, m), 5.79 (1H, dd, J ) 10.2, 4.5 Hz), 5.31 (1H, d, J ) 10.2 Hz),
5.17 (1H, d, J ) 17.1 Hz), 5.07 (1H, d, J ) 10.2 Hz), 4.92 (1H, s),
3.96 (2H, m), 3.70 (3H, s), 3.64 (1H, s), 2.89 (3H, s), 2.72 (1H, d, J
) 15.0 Hz), 2.52(1H, s), 2.40 (1H, m), 2.04 (3H, s), 1.15 (1H, m),
0.91 (1H, m), 0.45 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ
171.0 (C), 161.1 (C), 154.8 (C), 135.0 (CH), 130.4 (CH), 126.2 (C),
124.3 (CH), 122.8 (CH), 117.3 (CH2), 104.5 (CH), 96.1 (CH), 81.0
(CH), 78.0 (C), 77.6 (CH), 72.8 (CH2), 72.5 (CH2), 68.1 (CH), 55.4
(OCH3), 52.0 (C), 52.0 (CH2), 51.0 (CH2), 44.8 (CH2), 42.7 (C), 39.4
(CH3), 31.7 (CH2), 21.1 (CH3), 7.7 (CH3); ESIMS m/z 469.3 [M +
1]+.
5.41 (1H, d, J ) 10.2 Hz), 5.40 (1H, s), 5.02 (1H, s), 4.16 (1H, d, J )
11.7 Hz), 4.12 (1H, d, J ) 11.7 Hz), 3.79 (3H, s), 3.58 (3H, s), 2.89
(3H, s), 2.59 (1H, s), 2.15 (3H, s), 2.10 (3H, s), 1.43 (1H, m), 1.21
(1H, m), 0.96 (3H, t, J ) 7.5 Hz), 0.79 (3H, t, J ) 6.9 Hz); 13C NMR
(75 MHz, CDCl3) δ 174.7 (C), 170.9 (C), 170.7 (C), 157.7 (C), 153.3
(C), 139.7 (C), 134.9 (C), 130.8 (C), 129.5 (CH), 129.3 (C), 124.6
(CH), 123.8 (CH), 123.5 (CH), 123.5 (C), 122.2 (CH), 121.3 (C), 118.8
(CH), 118.3 (CH), 117.2 (C), 110.4 (CH), 94.6 (CH), 81.5 (CH), 76.6
(CH), 76.0 (C), 66.3 (CH2), 66.0 (CH), 55.7 (OCH3), 55.3 (C), 54.4
(CH2), 52.4 (OCH3), 52.3 (CH2), 51.9 (C), 50.1 (CH2), 49.9 (CH2),
45.7 (CH2), 44.9 (CH2), 42.3 (C), 39.9 (CH3), 34.2 (CH2), 32.8 (CH),
31.4 (CH2), 27.7 (CH2), 25.4 (CH2), 21.0 (CH3), 20.9 (CH3), 12.2 (CH3),
8.2 (CH3); ESIMS m/z 807.5 [M + 1]+; HRESIMS m/z 807.4337 (calcd
for C47H58N4O8, 807.4333).
3-Demethoxycarbonyl-3-(propyloxy)methylvindoline (20a). Com-
pound 20a was prepared using 1-bromopropane as starting material.
1
3-Demethoxycarbonyl-3-(ethylcarbonyloxy)methylanhydrovin-
Yield: 51%; H NMR (300 MHz, CDCl3) δ 8.80 (1H, brs), 6.86 (1H,
blastine (6b): [R]20 +55.1 (c 0.30, CHCl3); 1H NMR (300 MHz,
d, J ) 8.1 Hz), 6.26 (1H, dd, J ) 8.1, 2.1 Hz), 6.10 (1H, d, J ) 2.1
Hz), 5.87 (1H, dd, J ) 10.5, 4.8 Hz), 5.38 (1H, d, J ) 10.5 Hz), 5.00
(1H, s), 3.79 (3H, s), 3.72 (1H, s), 3.52-3.26 (6H, m), 2.95 (3H, s),
2.77 (1H, d, J ) 15.9 Hz), 2.58 (1H, s), 2.50-2.40 (1H, m), 2.31-2.19
(2H, m), 2.12 (3H, s), 1.73-1.55 (2H, m), 1.32-1.20 (1H, m),
1.05-0.95 (1H, m), 0.89 (3H, t, J ) 7.2 Hz), 0.51 (3H, t, J ) 7.2 Hz);
13C NMR (75 MHz, CDCl3) δ 170.4 (C), 160.7 (C), 154.3 (C), 130.0
(CH), 125.9 (C), 123.7 (CH), 122.3 (CH), 103.9 (CH), 95.6 (CH), 80.5
(CH), 77.1 (CH), 76.9 (C), 73.1 (CH2), 72.7 (CH2), 67.7 (CH), 54.9
(OCH3), 51.6 (CH2), 51.5 (C), 50.5 (CH2), 44.4 (CH2), 42.2 (C), 38.7
(CH3), 31.3 (CH2), 22.4 (CH2), 20.7 (CH3), 10.5 (CH3), 7.2 (CH3);
ESIMS m/z 471.2 [M + 1]+.
D
CDCl3) δ 9.13 (1H, s), 8.03 (1H, s), 7.53 (1H, d, J ) 7.5 Hz), 7.14
(3H, m), 6.61 (1H, s), 6.18 (1H, s), 5.89 (1H, dd, J ) 10.5, 4.5 Hz),
5.51 (1H, d, J ) 6.0 Hz), 5.43 (1H, d, J ) 10.5 Hz), 5.06 (1H, s), 4.23
(1H, d, J ) 11.4 Hz), 4.02 (1H, d, J ) 11.4 Hz), 3.83 (3H, s), 3.65
(3H, s), 2.92 (3H, s), 2.64 (1H, s), 2.42 (2H, q, J ) 7.8 Hz), 2.19 (3H,
s), 1.95 (2H, q, J ) 7.5 Hz), 1.43 (1H, m), 1.21 (1H, m), 1.16 (3H, t,
J ) 7.8 Hz), 1.01 (3H, t, J ) 7.5 Hz), 0.82 (3H, t, J ) 7.2 Hz); 13C
NMR (75 MHz, CDCl3) δ 174.8 (C), 174.2 (C), 171.1 (C), 158.0 (C),
153.5 (C), 140.0 (C), 135.1 (C), 131.1 (C), 129.7 (CH), 129.5 (C),
124.7 (CH), 124.0 (CH), 123.8 (C), 123.7 (CH), 122.4 (CH), 121.5
(C), 119.0 (CH), 118.4 (CH), 117.4 (C), 110.5 (CH), 94.8 (CH), 81.8
(CH), 76.9 (CH), 76.2 (C), 66.4 (CH), 66.3 (CH2), 55.9 (OCH3), 55.6
(C), 54.6 (CH2), 52.6 (C), 52.4 (OCH3), 52.3 (CH2), 50.4 (CH2), 50.2
(CH2), 46.0 (CH2), 45.1 (CH2), 42.6 (C), 40.0 (CH3), 34.5 (CH2), 33.0
3-Demethoxycarbonyl-3-(butyloxy)methylvindoline (21a). Com-
pound 21a was prepared using 1-bromobutane as starting material.
1
Yield: 56%; H NMR (300 MHz, CDCl3) δ 8.80 (1H, brs), 6.83 (1H,
d, J ) 8.1 Hz), 6.22 (1H, dd, J ) 8.1, 2.4 Hz), 6.06 (1H, d, J ) 2.4
Hz), 5.81 (1H, dd, J ) 10.2, 4.8 Hz), 5.37 (1H, d, J ) 10.2 Hz), 4.96
(1H, s), 3.74 (3H, s), 3.68 (1H, s), 2.90 (3H, s), 2.74 (1H, d, J ) 16.2
Hz), 2.54 (1H, s), 2.40 (1H, m), 2.09 (3H, s), 1.54 (1H, m), 0.92 (1H,
m), 0.85 (3H, t, J ) 7.2 Hz), 0.48 (3H, t, J ) 7.2 Hz); 13C NMR (75
MHz, CDCl3) δ 170.9 (C), 161.0 (C), 154.6 (C), 130.3 (CH), 126.2
(C), 124.1 (CH), 122.6 (CH), 104.2 (CH), 95.9 (CH), 80.8 (CH), 77.5
(C), 77.3 (CH), 73.0 (CH2), 71.6 (CH2), 68.1 (CH), 53.3 (OCH3), 52.0
(CH2), 52.9 (C), 50.8 (CH2), 44.7 (CH2), 42.5 (C), 39.0 (CH3), 31.6
(CH2), 21.0 (CH3), 19.5 (CH2), 14.0(CH2), 15.1 (CH3), 7.6 (CH3);
ESIMS m/z 485.4 [M + 1]+.
(CH), 31.6 (CH2), 27.9 (CH2), 27.6 (CH2), 25.8 (CH2), 21.1 (CH3),
+
12.4 (CH
3), 9.2 (CH3), 8.4 (CH3); ESIMS m/z 821.5 [M + 1] ;
HRESIMS m/z 821.4484 (calcd for C48H60N4O8, 821.4489).
3-Demethoxycarbonyl-3-(isopropylcarbonyloxy)methylan-
1
hydrovinblastine (7b): [R]20 +60.0 (c 0.25, CHCl3); H NMR (300
D
MHz, CDCl3) δ 9.00 (1H, s), 8.02 (1H, s), 7.52 (1H, d, J ) 7.5 Hz),
7.13 (3H, m), 6.61 (1H, s), 6.17 (1H, s), 5.85 (1H, dd, J ) 10.2, 6.3
Hz), 5.49 (1H, d, J ) 6.0 Hz), 5.41 (1H, d, J ) 10.2 Hz), 5.05 (1H, s),
4.24 (1H, d, J ) 11.4 Hz), 3.99 (1H, d, J ) 11.4 Hz), 3.82 (3H, s),
3.64 (3H, s), 2.92 (3H, s), 2.59 (1H, s), 2.17 (3H, s), 1.94 (2H, q, J )
7.5 Hz), 1.47 (1H, m), 1.21 (1H, m), 1.19 (6H, d, J ) 5.1 Hz), 1.00
(3H, t, J ) 7.5 Hz), 0.81 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz,
CDCl3) δ 176.8 (C), 174.5 (C), 171.1 (C), 157.8 (C), 153.7 (C), 137.9
(C), 135.0 (C), 130.9 (C), 129.6 (CH), 129.0 (C), 124.7 (CH), 124.1
(C), 124.0 (CH), 123.5 (CH), 122.8 (CH), 120.5 (C), 119.4 (CH), 118.2
(CH), 115.6 (C), 110.6 (CH), 94.6 (CH), 81.6 (CH), 76.7 (CH), 76.1
(C), 66.4 (CH), 65.9 (CH2), 55.8 (OCH3), 55.3 (C), 54.4 (CH2), 52.5
(OCH3), 52.4 (C), 51.0 (CH2), 50.4 (CH2), 50.2 (CH2), 45.5 (CH2),
45.2 (CH2), 42.5 (C), 39.7 (CH3), 34.2 (CH2), 33.9 (CH), 31.6 (CH),
31.5 (CH2), 27.8 (CH2), 23.4 (CH2), 21.0 (CH3), 19.1 (CH3), 18.9 (CH3),
11.9 (CH3), 8.3 (CH3); ESIMS m/z 835.5 [M + 1]+; HRESIMS m/z
835.4653 (calcd for C49H62N4O8, 835.4646).
3-Demethoxycarbonyl-3-(4-methoxylbenzyloxy)methylvindo-
line (22a). Compound 22a was prepared using 4-methoxybenzyl
bromide as starting material. Yield: 65%; 1H NMR (300 MHz, CDCl3)
δ 7.08 (2H, d, J ) 8.1 Hz), 6.85 (1H, d, J ) 8.1 Hz), 6.70 (2H, d, J
) 8.1 Hz), 6.25 (1H, d, J ) 8.1 Hz), 6.09 (1H, s), 5.51 (1H, dd, J )
10.2, 4.2 Hz), 5.36 (1H, d, J ) 10.2 Hz), 4.98 (1H, s), 4.58 (2H, q, J
) 11.7 Hz), 3.74 (6H, s), 3.54 (1H, s), 3.51-3.32 (4H, m), 2.93 (3H,
s), 2.77 (1H, d, J ) 16.2 Hz), 2.58 (1H, s), 2.44 (1H, m), 2.26 (2H,
m), 2.04 (3H, s), 1.25 (1H, m), 0.93 (1H, m), 0.50 (3H, t, J ) 7.2 Hz);
13C NMR (75 MHz, CDCl3) δ 170.9 (C), 161.1 (C), 160.0 (C), 154.6
(C), 130.7 (CH), 130.1 (C), 128.5 (2 CH), 125.9 (C), 124.5 (CH), 123.1
(CH), 114.2 (2CH), 105.8 (CH), 97.2 (CH), 81.0 (CH), 78.0 (C), 77.6
(CH), 72.8 (CH2), 72.5 (CH2), 67.5 (CH), 55.7 (2OCH3), 52.0 (C), 51.8
(CH2), 45.2 (CH2), 44.3 (CH2), 43.2 (C), 40.3 (CH3), 31.6 (CH2), 21.3
(CH3), 7.8 (CH3); ESIMS m/z 549.3 [M + 1]+.
3-Demethoxycarbonyl-3-(tert-butylcarbonyloxy)methylanhy-
drovinblastine (8b): [R]20D +58.1 (c 0.20, CHCl3); 1H NMR (300 MHz,
DMSO-d6) δ 9.86 (1H, s), 8.21 (1H, s), 7.44 (1H, d, J ) 7.8 Hz), 7.28
(1H, d, J ) 7.8 Hz), 6.99 (3H, m), 6.47 (1H, s), 6.30 (1H, s), 5.73
(1H, dd, J ) 10.2, 4.5 Hz), 5.45 (2H, m), 4.82 (1H, s), 4.11 (1H, d, J
) 11.4 Hz), 3.78 (3H, s), 3.70 (1H, d, J ) 11.4 Hz), 3.57 (3H, s), 2.93
(3H, s), 2.70 (1H, s), 2.08 (3H, s), 1.15 (9H, s), 0.96 (3H, t, J ) 7.5
Hz), 0.66 (3H, t, J ) 6.9 Hz); 13C NMR (75 MHz, DMSO-d6) δ 177.1
(C), 173.9 (C), 170.7 (C), 157.4 (C), 153.5 (C), 137.1 (C), 135.7 (C),
131.3 (C), 130.5 (CH), 128.4 (C), 124.5 (CH), 123.7 (CH), 123.7 (CH),
123.7 (C), 121.2 (CH), 120.3 (C), 118.5 (CH), 117.7 (CH), 113.2 (C),
112.0 (CH), 94.6 (CH), 81.5 (CH), 76.2 (CH), 75.9 (C), 64.5 (CH2),
64.0 (CH), 56.2 (OCH3), 55.0 (C), 53.7 (CH2), 52.4 (OCH3), 52.3 (CH2),
52.3 (C), 49.6 (CH2), 48.9 (CH2), 45.5 (CH2), 45.2 (CH2), 42.0 (C),
39.9 (CH3), 38.5 (C), 34.7 (CH2), 31.5 (CH), 30.5 (CH2), 27.2 (CH2),
27.0 (3CH3), 21.1 (CH2), 20.8 (CH3), 11.6 (CH3), 7.9 (CH3); ESIMS
m/z 849.5 [M + 1]+; HRESIMS m/z 849.4809 (calcd for C50H64N4O8,
849.4802).
General Procedure for the Preparation of 5b-22b. Catharanthine
tartrate (486 mg, 1 mmol) and anhydrous ferric chloride (486 mg, 3
mmol) were combined in a mixture of glycine buffer (containing 320
mg of glycine and 250 mg of sodium chloride in 40 mL of water),
along with hydrochloride acid (40 mL, 0.1 N), under a nitrogen
atmosphere. After 10 min of stirring at room temperature, compounds
5a-22a (1 mmol) were added individually. After 8 h of stirring at
room temperature, sodium borohydride (80 mg) in ammonium hydrox-
ide (8 mL) was added dropwise at 0 °C and left to react for 15 min.
The reaction mixture was extracted with CH2Cl2 (4 × 20 mL), and the
organic phase was filtered with Celite and concentrated at reduced
pressure, then the residue was followed by column chromatography
on silica gel (100:1, CHCl3-MeOH) to afford each compound
(5b-22b) as a white solid in over 50% yield.
3-Demethoxycarbonyl-3-(methylcarbonyloxy)methylanhydrovin-
3-Demethoxycarbonyl-3-(isobutylcarbonyloxy)methylanhydrovin-
blastine (5b): [R]20 +54.0 (c 0.10, CHCl3); 1H NMR (300 MHz,
blastine (9b): [R]20 +62.1 (c 0.20, CHCl3); 1H NMR (300 MHz,
D
D
CDCl3) δ 9.25 (1H, s), 8.06 (1H, s), 7.48 (1H, d, J ) 7.2 Hz), 7.10
(3H, m), 6.59 (1H, s), 6.17 (1H, s), 5.86 (1H, dd, J ) 10.2, 4.5 Hz),
CDCl3) δ 9.05 (1H, s), 8.02 (1H, s), 7.53 (1H, d, J ) 7.5 Hz), 7.14
(3H, m), 6.62 (1H, s), 6.18 (1H, s), 5.88 (1H, dd, J ) 10.2, 6.3 Hz),

1674 Journal of Natural Products, 2008, Vol. 71, No. 10
Zhang et al.
5.48 (1H, d, J ) 6.0 Hz), 5.43 (1H, d, J ) 10.2 Hz), 5.06 (1H, s), 4.25
(1H, d, J ) 11.7 Hz), 4.00 (1H, d, J ) 11.7 Hz), 3.83 (3H, s), 3.62
(3H, s), 2.92 (3H, s), 2.60 (1H, s), 2.19 (3H, s), 1.94 (2H, q, J ) 7.5
Hz), 1.47 (1H, m), 1.21 (1H, m), 1.01 (3H, t, J ) 7.5 Hz), 0.97 (6H,
d, J ) 6.6 Hz), 0.82 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3)
δ 174.6 (C), 172.7 (C), 171.0 (C), 157.8 (C), 153.5 (C), 139.3 (C),
135.0 (C), 130.9 (C), 129.6 (CH), 129.3 (C), 124.6 (CH), 123.9 (C),
123.9 (CH), 123.6 (CH), 122.4 (CH), 121.1 (C), 119.0 (CH), 118.3
(CH), 116.7 (C), 110.4 (CH), 94.6 (CH), 81.6 (CH), 76.7 (CH), 76.1
(C), 66.3 (CH), 65.9 (CH2), 55.8 (OCH3), 55.4 (C), 54.4 (CH2), 52.4
(OCH3), 52.4 (C), 51.8 (CH2), 50.3 (CH2), 50.1 (CH2), 45.8 (CH2),
45.1 (CH2), 43.2 (CH2), 42.5 (C), 39.9 (CH3), 34.3 (CH2), 32.5 (CH),
31.5 (CH2), 27.8 (CH2), 25.5 (CH), 25.0 (CH2), 22.4 (CH3), 22.3 (CH3),
21.0 (CH3), 12.2 (CH3), 8.2 (CH3); ESIMS m/z 849.5 [M + 1]+;
HRESIMS m/z 849.4807 (calcd for C50H64N4O8, 849.4802).
3-Demethoxycarbonyl-3-(2-methoxylphenylcarbonyloxy)meth-
ylanhydrovinblastine (13b): [R]20D +63.0 (c 0.30, CHCl3); 1H NMR
(300 MHz, CDCl3) δ 9.07 (1H, s), 8.05 (1H, s), 7.87 (1H, d, J ) 7.8
Hz), 7.53 (1H, d, J ) 7.2 Hz), 7.46 (1H, t, J ) 7.8 Hz), 7.14 (3H, m),
7.00 (1H, t, J ) 7.8 Hz), 6.95 (1H, d, J ) 7.8 Hz), 6.63 (1H, s), 6.17
(1H, s), 5.88 (1H, dd, J ) 10.2, 4.5 Hz), 5.48 (1H, d, J ) 9.3 Hz),
5.44 (1H, d, J ) 10.2 Hz), 5.14 (1H, s), 4.50 (1H, d, J ) 11.4 Hz),
4.18 (1H, d, J ) 11.4 Hz), 3.85 (3H, s), 3.82 (3H, s), 3.71 (1H, s),
3.62 (3H, s), 2.99 (3H, s), 2.62 (1H, s), 2.18 (3H, s), 1.95 (2H, q, J )
7.5 Hz), 1.43 (1H, m), 1.21 (1H, m), 1.00 (3H, t, J ) 7.5 Hz), 0.83
(3H, t, J ) 6.9 Hz); 13C NMR (75 MHz, CDCl3) δ 174.9 (C), 171.2
(C), 166.0 (C), 159.3 (C), 158.0 (C), 153.7 (C), 140.1 (C), 135.1 (C),
133.7 (CH), 132.1 (CH), 131.1 (2 C), 129.8 (CH), 129.6 (C), 124.7
(CH), 124.0 (CH), 123.8 (CH), 122.4 (CH), 121.3 (C), 120.2 (CH),
120.0 (C), 119.0 (CH), 118.5 (CH), 117.4 (C), 112.0 (CH), 110.6 (CH),
94.6 (CH), 82.0 (CH), 76.9 (CH), 76.4 (C), 66.5 (CH2), 66.5 (CH),
56.0 (OCH3), 55.9 (OCH3), 55.6 (C), 54.6 (CH2), 52.6 (C), 52.5 (OCH3),
52.3 (CH2), 50.4 (CH2), 50.2 (CH2), 46.0 (CH2), 45.3 (CH2), 42.7 (C),
39.7 (CH3), 34.5 (CH2), 33.0 (CH), 31.7 (CH2), 28.0 (CH2), 25.8 (CH2),
21.2 (CH3), 12.4 (CH3), 8.4 (CH3); ESIMS m/z 899.5 [M + 1]+;
HRESIMS m/z 899.4591 (calcd for C53H62N4O9, 899.4595).
3-Demethoxycarbonyl-3-(4-methoxylphenylcarbonyloxy)meth-
ylanhydrovinblastine (14b): [R]20D +60.1 (c 0.30, CHCl3); 1H NMR
(300 MHz, CDCl3) δ 9.10 (1H, s), 8.06 (1H, s), 8.04 (2H, d, J ) 8.7
Hz), 7.53 (1H, d, J ) 7.8 Hz), 7.14 (3H, m), 6.92 (2H, d, J ) 8.7 Hz),
6.64 (1H, s), 6.15 (1H, s), 5.89 (1H, dd, J ) 10.5, 4.5 Hz), 5.47 (1H,
d, J ) 9.6 Hz), 5.44 (1H, d, J ) 10.5 Hz), 5.18 (1H, s), 4.51 (1H, d,
J ) 11.4 Hz), 4.16 (1H, d, J ) 11.4 Hz), 3.85 (3H, s), 3.82 (3H, s),
3.69 (1H, s), 3.63 (3H, s), 2.93 (3H, s), 2.64 (1H, s), 2.17 (3H, s), 1.94
(2H, q, J ) 7.5 Hz), 1.43 (1H, m), 1.21 (1H, m), 1.00 (3H, t, J ) 7.5
Hz), 0.83 (3H, t, J ) 6.9 Hz); 13C NMR (75 MHz, CDCl3) δ 174.9
(C), 171.2 (C), 166.0 (C), 163.6 (C), 158.0 (C), 153.6 (C), 140.0 (C),
135.1 (C), 132.0 (2 CH), 132.0 (C), 131.4 (C), 129.9 (CH), 129.6 (C),
124.8 (CH), 124.0 (CH), 123.9 (CH), 122.6 (C), 122.4 (CH), 121.4
(C), 119.0 (CH), 118.5 (CH), 117.4 (C), 113.8 (2 CH), 110.6 (CH),
94.6 (CH), 82.5 (CH), 76.9 (CH), 76.4 (C), 66.5 (CH2), 66.4 (CH),
56.0 (OCH3), 55.6 (C), 55.5 (OCH3), 54.6 (CH2), 52.8 (C), 52.5 (OCH3),
52.3 (CH2), 50.5 (CH2), 50.3 (CH2), 46.0 (CH2), 45.4 (CH2), 42.8 (C),
40.0 (CH3), 34.5 (CH2), 33.0 (CH), 31.7 (CH2), 28.0 (CH2), 25.8 (CH2),
21.2 (CH3), 12.4 (CH3), 8.5 (CH3); ESIMS m/z 899.5 [M + 1]+;
HRESIMS m/z 899.4597 (calcd for C53H62N4O9, 899.4595).
3-Demethoxycarbonyl-3-(cyclopropylcarbonyloxy)methylanhy-
1
drovinblastine (10b): [R]20 +60.0 (c 0.20, CHCl3); H NMR (300
D
MHz, CDCl3) δ 9.14 (1H, s), 8.03 (1H, s), 7.53 (1H, d, J ) 7.8 Hz),
7.14 (3H, m), 6.62 (1H, s), 6.19 (1H, s), 5.89 (1H, dd, J ) 10.2, 3.9
Hz), 5.51 (1H, d, J ) 6.0 Hz), 5.44 (1H, d, J ) 10.2 Hz), 5.06 (1H, s),
4.24 (1H, d, J ) 11.4 Hz), 4.02 (1H, d, J ) 11.4 Hz), 3.84 (3H, s),
3.65 (1H, s), 3.63 (3H, s), 2.94 (3H, s), 2.62 (1H, s), 2.18 (3H, s), 1.94
(2H, q, J ) 7.5 Hz), 1.47 (1H, m), 1.21 (1H, m), 1.01 (5H, t, J ) 7.5
Hz), 0.86 (2H, t, J ) 7.5 Hz), 0.82 (3H, t, J ) 7.2 Hz); 13C NMR (75
MHz, CDCl3) δ 174.9 (C), 174.8 (C), 171.8 (C), 157.9 (C), 153.5 (C),
139.8 (C), 135.0 (C), 130.9 (C), 129.7 (CH), 129.4 (C), 124.6 (CH),
123.9 (CH), 123.7 (CH), 123.6 (C), 122.3 (CH), 121.3 (C), 118.9 (CH),
118.4 (CH), 117.3 (C), 110.5 (CH), 94.7 (CH), 81.7 (CH), 76.8 (CH),
76.0 (C), 66.4 (CH2), 66.3 (CH), 55.8 (OCH3), 55.5 (C), 54.5 (CH2),
52.5 (C), 52.4 (OCH3), 52.0 (CH2), 50.3 (CH2), 50.1 (CH2), 45.8 (CH2),
45.1 (CH2), 42.5 (C), 40.0 (CH3), 34.4 (CH2), 32.9 (CH), 31.5 (CH2),
27.9 (CH2), 25.4 (CH2), 20.9 (CH3), 12.8 (CH), 12.3 (CH3), 8.7 (CH2),
8.6 (CH2), 8.3 (CH3); ESIMS m/z 833.5 [M + 1]+; HRESIMS m/z
833.4483 (calcd for C49H60N4O8, 833.4489).
3-Demethoxycarbonyl-3-(benzylcarbonyloxy)methylanhy-
1
drovinblastine (11b): [R]20 +63.1 (c 0.21, CHCl3); H NMR (300
D
MHz, CDCl3) δ 9.11 (1H, s), 8.03 (1H, s), 7.53 (1H, d, J ) 7.5 Hz),
7.29 (5H, m), 7.14 (3H, m, 3 H), 6.62 (1H, s), 6.11 (1H, s), 5.88 (1H,
dd, J ) 10.2, 4.5 Hz), 5.46 (2H, m), 5.04 (1H, s), 4.32 (1H, d, J )
11.4 Hz), 3.96 (1H, d, J ) 11.4 Hz), 3.82 (3H, s), 3.72 (2H, s), 3.61
(3H, s), 3.44 (1H, s), 2.60 (3H, s), 2.59 (1H, s), 2.17 (3H, s), 1.94 (2H,
q, J ) 7.5 Hz), 1.43 (1H, m), 1.21 (1H, m), 1.01 (3H, t, J ) 7.5 Hz),
0.83 (3H, t, J ) 6.9 Hz); 13C NMR (75 MHz, CDCl3) δ 174.8 (C),
171.1 (C), 171.0 (C), 157.9 (C), 153.5 (C), 140.1 (C), 135.0 (C), 134.0
(C), 131.0 (C), 129.7 (CH), 129.5 (2CH), 128.5 (2CH), 127.0 (CH),
127.0 (C), 124.7 (CH), 123.9 (CH), 123.6 (CH), 123.6 (C), 122.3 (CH),
121.4 (C), 118.9 (CH), 118.4 (CH), 117.4 (C), 110.5 (CH), 94.7 (CH),
81.6 (CH), 76.7 (CH), 76.2 (C), 66.4 (CH2), 66.2 (CH), 55.8 (OCH3),
55.5 (C), 54.5 (CH2), 52.5 (OCH3), 52.4 (CH2), 52.3 (C), 50.2 (CH2),
50.1 (CH2), 46.0 (CH2), 45.1 (CH2), 42.5 (C), 41.4 (CH2), 39.7 (CH3),
34.4 (CH2), 33.0 (CH), 31.6 (CH2), 27.8 (CH2), 25.9 (CH2), 21.0 (CH3),
12.4 (CH3), 8.3 (CH3); ESIMS m/z 883.5 [M + 1]+; HRESIMS m/z
883.4642 (calcd for C53H62N4O8, 883.4646).
3-Demethoxycarbonyl-3-(2-chlorophenylcarbonyloxy)methyl-
1
anhydrovinblastine (15b): [R]20 +64.1 (c 0.30, CHCl3); H NMR
D
(300 MHz, CDCl3) δ 9.10 (1H, s), 8.05 (1H, s), 7.89 (1H, d, J ) 6.6
Hz), 7.53 (1H, d, J ) 7.2 Hz), 7.42 (2H, d, J ) 7.8 Hz), 7.31 (1H, t,
J ) 7.8 Hz), 7.14 (3H, m), 6.63 (1H, s), 6.18 (1H, s), 5.89 (1H, dd, J
) 10.2, 4.5 Hz), 5.48 (1H, d, J ) 9.3 Hz), 5.45 (1H, d, J ) 10.2 Hz),
5.14 (1H, s), 4.52 (1H, d, J ) 11.4 Hz), 4.26 (1H, d, J ) 11.4 Hz),
3.82 (3H, s), 3.68 (1H, s), 3.62 (3H, s), 3.00 (3H, s), 2.62 (1H, s), 2.19
(3H, s), 1.94 (2H, q, J ) 7.5 Hz), 1.50 (1H, m), 1.29 (1H, m), 1.00
(3H, t, J ) 7.5 Hz), 0.83 (3H, t, J ) 6.9 Hz); 13C NMR (75 MHz,
CDCl3)δ 174.9 (C), 171.2 (C), 165.3 (C), 158.0 (C), 153.6 (C), 140.1
(C), 135.1 (C), 133.9 (C), 132.7 (CH), 131.7 (CH), 131.2 (CH), 131.1
(C), 130.1 (C), 129.8 (CH), 129.6 (C), 126.7 (CH), 124.8 (CH), 124.0
(CH), 123.8 (CH), 122.4 (CH), 121.5 (2C), 119.0 (CH), 118.5 (CH),
117.4 (C), 110.6 (CH), 94.7 (CH), 82.0 (CH), 76.8 (CH), 76.3 (C),
67.2 (CH2), 66.4 (CH), 56.0 (OCH3), 55.6 (C), 54.6 (CH2), 52.7 (C),
52.5 (OCH3), 52.2 (CH2), 50.4 (CH2), 50.2 (CH2), 46.0 (CH2), 45.3
(CH2), 42.7 (C), 40.2 (CH3), 34.5 (CH2), 33.0 (CH), 31.7 (CH2), 28.0
(CH2), 25.7 (CH2), 21.2 (CH3), 12.4 (CH3), 8.4 (CH3); ESIMS m/z 903.5
[M + 1]+; HRESIMS m/z 903.4106 (calcd for C52H60ClN4O8, 903.4100).
3-Demethoxycarbonyl-3-(phenylcarbonyloxy)methylanhy-
1
drovinblastine (12b): [R]20 +57.1 (c 0.20, CHCl3); H NMR (300
D
MHz, CDCl3) δ 9.12 (1H, s), 8.09 (2H, d, J ) 6.9 Hz), 8.06 (1H, s),
7.55 (2H, m), 7.45 (1H, d, J ) 7.2 Hz), 7.44 (1H, t, J ) 7.2 Hz), 7.15
(3H, m), 6.65 (1H, s), 6.17 (1H, s), 5.90 (1H, dd, J ) 10.2, 4.5 Hz),
5.48 (1H, d, J ) 9.6 Hz), 5.45 (1H, d, J ) 10.2 Hz), 5.18 (1H, s), 4.56
(1H, d, J ) 11.4 Hz), 4.20 (1H, d, J ) 11.4 Hz), 3.88 (3H, s), 3.73
(1H, s), 3.65 (3H, s), 2.96 (3H, s), 2.65 (1H, s), 2.18 (3H, s), 1.94 (2H,
q, J ) 7.5 Hz), 1.43 (1H, m), 1.21 (1H, m), 1.00 (3H, t, J ) 7.5 Hz),
0.84 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ 174.9 (C),
171.2 (C), 166.3 (C), 158.0 (C), 153.6 (C), 140.0 (C), 135.2 (C), 133.2
(CH), 131.1 (C), 131.0 (C), 130.2 (C), 129.9 (3CH), 129.6 (C), 128.5
(2CH), 124.8 (CH), 124.0 (CH), 123.9 (CH), 122.4 (CH), 121.5 (C),
119.0 (CH), 118.5 (CH), 117.5 (C), 110.6 (CH), 94.6 (CH), 82.4 (CH),
76.9 (CH), 76.4 (C), 66.7 (CH2), 66.4 (CH), 56.0 (OCH3), 55.6 (C),
54.6 (CH2), 52.5 (OCH3), 52.2 (CH2), 52.2 (C), 50.4 (CH2), 50.3 (CH2),
46.0 (CH2), 45.4 (CH2), 42.7 (C), 40.1 (CH3), 34.5 (CH2), 33.0 (CH),
31.7 (CH2), 28.0 (CH2), 25.7 (CH2), 21.2 (CH3), 12.4 (CH3), 8.4 (CH3);
ESIMS m/z 869.5 [M + 1]+; HRESIMS m/z 869.4485 (calcd for
C52H60N4O8, 869.4489).
3-Demethoxycarbonyl-3-(2-chlorophenylcarbonyloxy)methyl-
1
anhydrovinblastine (16b): [R]20 +64.0 (c 0.30, CHCl3); H NMR
D
(300 MHz, CDCl3) δ 9.15 (1H, s), 8.06 (1H, s), 8.02 (2H, d, J ) 8.4
Hz), 7.53 (1H, d, J ) 7.5 Hz), 7.41 (2H, d, J ) 8.4 Hz), 7.14 (3H, m),
6.65 (1H, s), 6.16 (1H, s), 5.89 (1H, dd, J ) 10.2, 4.5 Hz), 5.48 (1H,
d, J ) 8.4 Hz), 5.44 (1H, d, J ) 10.2 Hz), 5.17 (1H, s), 4.54 (1H, d,
J ) 11.7 Hz), 4.20 (1H, d, J ) 11.7 Hz), 3.82 (3H, s), 3.66 (1H, s),
3.64 (3H, s), 2.93 (3H, s), 2.65 (1H, s), 2.17 (3H, s), 1.94 (2H, q, J )
7.5 Hz), 1.53 (1H, m), 1.29 (1H, m), 0.98 (3H, t, J ) 7.5 Hz), 0.84
(3H, t, J ) 7.2 Hz); 13C NMR (75 MHz, CDCl3)δ 174.9 (C), 171.2
(C), 165.5 (C), 158.1 (C), 153.5 (C), 140.1 (C), 139.6 (C), 135.2 (C),
131.3 (2 CH), 131.3 (C), 131.1 (C), 129.8 (CH), 129.6 (C), 128.9 (2
CH), 128.6 (C), 124.8 (CH), 124.0 (CH), 123.9 (CH), 122.4 (CH), 121.6

Cytotoxic Ester AnhydroVinblastine DeriVatiVes
Journal of Natural Products, 2008, Vol. 71, No. 10 1675
(C), 119.0 (CH), 118.5 (CH), 117.5 (C), 110.6 (CH), 94.6 (CH), 82.6
(CH), 76.8 (CH), 76.4 (C), 67.8 (CH2), 66.3 (CH), 56.0 (OCH3), 55.6
(C), 54.6 (CH2), 52.8 (C), 52.5 (OCH3), 52.2 (CH2), 50.4 (CH2), 50.2
(CH2), 46.0 (CH2), 45.4 (CH2), 42.7 (C), 40.2 (CH3), 34.5 (CH2), 33.0
(CH), 31.7 (CH2), 28.0 (CH2), 25.8 (CH2), 21.2 (CH3), 12.4 (CH3), 8.4
(CH3); ESIMS m/z 903.5 [M + 1]+; HRESIMS m/z 903.4104 (calcd
for C52H60ClN4O8, 903.4100).
52.5 (OCH3), 52.4 (CH2), 52.3 (C), 50.5 (CH2), 50.2 (CH2), 46.1 (CH2),
45.2 (CH2), 42.3 (C), 39.1 (CH3), 34.6 (CH2), 33.1 (CH), 31.8 (CH2),
28.0 (CH2), 25.8 (CH2), 23.0 (CH2), 21.2 (CH3), 12.4 (CH3), 10.4 (CH3),
8.4 (CH3); ESIMS m/z 807.5 [M + 1]+; HRESIMS m/z 807.4699 (calcd
for C48H62N4O7, 807.4697).
3-Demethoxycarbonyl-3-(butyloxy)methylanhydrovinblastine (21b):
1
[R]20 +58.0 (c 0.30, CHCl3); H NMR (300 MHz, CDCl3) δ 9.04
D
(1H, s), 8.01 (1H, s), 7.51 (1H, d, J ) 7.8 Hz), 7.10 (3H, m), 6.60
(1H, s), 6.16 (1H, s), 5.86 (1H, dd, J ) 10.5, 4.2 Hz), 5.46 (1H, d, J
) 6 Hz), 5.45 (1H, d, J ) 10.5 Hz), 5.02 (1H, s), 3.82 (3H, s), 3.74
(1H, s), 3.60 (3H, s), 3.00 (3H, s), 2.58 (1H, s), 2.17 (3H, s), 1.00 (3H,
3-Demethoxycarbonyl-3-(4-nitrophenylcarbonyloxy)methyl-
1
anhydrovinblastine (17b): [R]20 +62.5 (c 0.30, CHCl3); H NMR
D
(300 MHz, CDCl3) δ 9.18 (1H, s), 8.28 (4H, d, J ) 6.0 Hz), 8.04 (1H,
s), 7.52 (1H, d, J ) 7.5 Hz), 7.14 (3H, m), 6.61 (1H, s), 6.17 (1H, s),
5.89 (1H, dd, J ) 10.2, 4.5 Hz), 5.53 (1H, s), 5.44 (1H, d, J ) 10.2
Hz), 5.17 (1H, s), 4.59 (1H, d, J ) 11.4 Hz), 4.26 (1H, d, J ) 11.4
Hz), 3.83 (3H, s), 3.71 (1H, s), 3.65 (3H, s), 2.95 (3H, s), 2.65 (1H, s),
2.18 (3H, s), 1.96 (2H, q, J ) 7.5 Hz), 1.53 (1H, m), 1.29 (1H, m),
1.01 (3H, t, J ) 7.5 Hz), 0.83 (3H, t, J ) 7.2 Hz); 13C NMR (75 MHz,
CDCl3) δ 174.8 (C), 171.3 (C), 164.5 (C), 158.1 (C), 153.6 (C), 150.7
(C), 135.6 (C), 135.2 (C), 131.0 (2CH), 131.0 (C), 130.4 (C), 129.7
(CH), 129.7 (C), 129.5 (C), 125.0 (CH), 123.9 (2 CH), 123.8 (2 CH),
122.7 (CH), 121.6 (C), 119.3 (CH), 118.5 (CH), 117.5 (C), 110.7 (CH),
94.8 (CH), 82.6 (CH), 76.7 (CH), 76.4 (C), 67.3 (CH2), 66.3 (CH),
56.1 (OCH3), 55.6 (C), 54.6 (CH2), 54.3 (C), 52.7 (OCH3), 51.8 (CH2),
50.4 (CH2), 50.4 (CH2), 45.7 (CH2), 45.4 (CH2), 42.8 (C), 40.3 (CH3),
34.4 (CH2), 32.5 (CH), 31.7 (CH2), 28.0 (CH2), 25.8 (CH2), 21.2 (CH3),
12.3 (CH3), 8.5 (CH3); ESIMS m/z 914.5 [M + 1]+; HRESIMS m/z
914.4344 (calcd for C52H60N5O10, 914.4340).
t, J ) 7.5 Hz), 0.89 (3H, t, J ) 7.2 Hz), 0.82 (3H, t, J ) 6.9 Hz); 13
C
NMR (75 MHz, CDCl3) δ 175.0 (C), 171.2 (C), 157.8 (C), 153.8 (C),
140.0 (C), 135.0 (C), 131.2 (C), 129.8 (CH), 129.5 (C), 124.7 (CH),
124.1 (C), 124.0 (CH), 123.7 (CH), 122.3 (CH), 120.8 (C), 118.9 (CH),
118.5 (CH), 117.4 (C), 110.5 (CH), 94.3 (CH), 80.9 (CH), 77.7 (CH),
77.2 (C), 72.6 (CH2), 71.6 (CH2), 66.4 (CH), 55.9 (OCH3), 55.5 (C),
54.5 (CH2), 52.4 (OCH3), 52.3 (C), 52.2 (CH2), 50.5 (CH2), 50.1 (CH2),
46.0 (CH2), 45.2 (CH2), 42.4 (C), 39.0 (CH3), 34.5 (CH2), 33.1 (CH),
31.7 (2 × CH2), 27.9 (CH2), 25.8 (CH2), 21.2 (CH3), 19.5 (CH2), 14.0
(CH3), 12.4 (CH3), 8.4 (CH3); ESIMS m/z 821.5 [M + 1]+; HRESIMS
m/z 821.4849 (calcd for C49H64N4O7, 821.4853).
3-Demethoxycarbonyl-3-(4-methoxylbenzyloxy)methylanhy-
1
drovinblastine (22b): [R]20 +60.1 (c 0.30, CHCl3); H NMR (300
D
MHz, DMSO-d6) δ 9.76 (1H, s), 8.08 (1H, s), 7.43 (1H, d, J ) 7.2
Hz), 7.24 (2H, d, J ) 7.8 Hz), 7.00 (3H, m), 6.91 (2H, d, J ) 7.8
Hz), 6.56 (1H, s), 6.42 (1H, s), 5.78 (1H, dd, J ) 10.2, 4.5 Hz),
5.44 (2H, m), 4.77 (1H, s), 4.41 (2H, q, J ) 11.7 Hz), 3.79 (3H, s),
3.74 (3H, s), 3.58 (3H, s), 2.96 (3H, s), 2.06 (3H, s), 1.43 (1H, m),
1.21 (1H, m), 0.95 (3H, t, J ) 7.5 Hz), 0.65 (3H, t, J ) 6.9 Hz);
13C NMR (75 MHz, DMSO-d6) δ 173.9 (C), 170.7 (C), 158.8 (C),
157.3 (C), 153.7 (C), 137.1 (C), 135.7 (C), 131.4 (C), 130.7 (C),
130.4 (CH), 129.5 (2 CH), 128.5 (C), 124.4 (CH), 123.9 (CH), 123.9
(CH), 123.9 (C), 121.7 (CH), 120.0 (C), 118.6 (CH), 117.8 (CH),
113.7 (2 CH), 113.2 (C), 112.0 (CH), 94.3 (CH), 80.7 (CH), 77.2
(CH), 76.9 (CH2), 72.6 (CH2), 71.4 (C), 64.4 (CH), 56.2 (OCH3),
55.1 (OCH3), 55.1 (2 C), 53.7 (CH2), 52.3 (OCH3), 52.2 (CH2), 49.6
(CH2), 48.9 (CH2), 45.6 (CH2), 45.2 (CH2), 42.0 (C), 39.9 (CH3),
34.7 (CH2), 31.6 (CH), 30.8 (CH2), 30.5 (CH2), 27.2 (CH2), 20.8
(CH3), 11.6 (CH3), 7.9 (CH3); ESIMS m/z 885.5 [M + 1]+;
HRESIMS m/z 885.4805 (calcd for C53H64N4O8, 885.4802).
Cytotoxicity Testing. The ditartrates of all compounds were used
for bioassays. The human non-small-cell lung cancer (A549) and
the cervical epithelial adenocarcinoma (HeLa) cell lines, obtained
from American Type Culture Collection (Rockville, MD), were used
for the determination of cytotoxicity with a sulforhodamine B (SRB)9
assay. Briefly, cells were seeded at 6000 cells/well in 96-well plates
(Falcon, CA) and allowed to attach overnight. Cells were treated in
triplicate with graded concentrations of compounds at 37 °C for
72 h. Then, they were fixed with 10% trichloroacetic acid and
incubated for 60 min at 4 °C. Next, the plates were washed and
dried. SRB solution (0.4% w/v in 1% acetic acid) was added and
the cultures incubated for an additional 15 min. After the plates
were washed and dried, bound stain was solubilized with Tris buffer,
and the optical densities were read on a plate reader (model Versa
Max, Molecular Devices) at 515 nm (A515). The results were
expressed as IC50 (the compound concentration required for 50%
growth inhibition of tumor cells) values, which were calculated by
the Logit method. The mean IC50 was determined from the results
of three independent tests.
3-Demethoxycarbonyl-3-(ethoxy)methylanhydrovinblastine (18b):
1
[R]20 +53.2 (c 0.30, CHCl3); H NMR (300 MHz, CDCl3) δ 9.03
D
(1H, s), 8.02 (1H, s), 7.51 (1H, d, J ) 7.8 Hz), 7.10 (3H, m), 6.60
(1H, s), 6.16 (1H, s), 5.86 (1H, dd, J ) 10.5, 4.2 Hz), 5.46 (1H, d, J
) 6.0 Hz), 5.45 (1H, d, J ) 10.5 Hz), 5.01 (1H, s), 3.82 (3H, s), 3.70
(1H, s), 3.60 (3H, s), 3.00 (3H, s), 2.58 (1H, s), 2.17 (3H, s), 1.43 (1H,
m), 1.22 (3H, t, J ) 6.9 Hz), 0.99 (3H, t, J ) 7.8 Hz), 0.81 (3H, t, J
) 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ 175.1 (C), 171.3 (C), 158.0
(C), 153.9 (C), 140.1 (C), 135.1 (C), 131.3 (C), 129.9 (CH), 129.6
(C), 124.7 (CH), 124.1 (CH), 123.8 (CH), 123.8 (C), 122.4 (CH), 121.3
(C), 119.0 (CH), 118.5 (CH), 117.2 (C), 110.6 (CH), 94.5 (CH), 81.0
(CH), 77.7 (C), 76.8 (CH), 72.4 (CH2), 66.9 (CH2), 66.5 (CH), 56.0
(OCH3), 55.6 (C), 54.6 (CH2), 52.5 (OCH3), 52.4 (CH2), 52.3 (C), 50.5
(CH2), 50.2 (CH2), 46.1 (CH2), 45.2 (CH2), 42.3 (C), 39.1 (CH3), 34.6
(CH2), 33.1 (CH), 31.8 (CH2), 28.0 (CH2), 25.8 (CH2), 21.2 (CH3),
15.1 (CH3), 12.4 (CH3), 8.4 (CH3); ESIMS m/z 793.5 [M + 1]+;
HRESIMS m/z 793.4538 (calcd for C47H60N4O7, 793.4540).
3-Demethoxycarbonyl-3-(allyloxy)methylanhydrovinblastine (19b):
1
[R]20 +57.5 (c 0.35, CHCl3); H NMR (300 MHz, CDCl3) δ 9.01
D
(1H, s), 8.01 (1H, s), 7.52 (1H, d, J ) 7.8 Hz), 7.10 (3H, m), 6.60
(1H, s), 6.16 (1H, s), 5.97 (1H, m), 5.86 (1H, dd, J ) 10.2, 4.5 Hz),
5.46 (1H, d, J ) 6.0 Hz), 5.45 (1H, d, J ) 10.2 Hz), 5.24 (1H, d, J )
17.1 Hz), 5.14 (1H, d, J ) 10.2 Hz), 5.02 (1H, s), 4.04 (2H, m), 3.84
(3H, s), 3.61(3H, s), 3.00 (3H, s), 2.59 (1H, s), 2.15 (3H, s), 1.43 (1H,
m), 1.21 (1H, m), 1.00 (3H, t, J ) 7.5 Hz), 0.82 (3H, t, J ) 6.9 Hz);
13C NMR (75 MHz, CDCl3) δ 175.1 (C), 171.3 (C), 158.0 (C), 154.0
(C), 140.1 (C), 135.2 (C), 135.0 (CH), 131.4 (C), 130.0 (CH), 129.6
(C), 124.8 (CH), 124.2 (CH), 123.9 (CH), 123.9 (C), 122.5 (CH), 121.1
(C), 119.0 (CH), 118.6 (CH), 117.2 (CH2), 117.2 (C), 110.7 (CH), 94.6
(CH), 81.2 (CH), 77.4 (CH), 77.4 (C), 72.9 (CH2), 72.2 (CH2), 66.7
(CH), 56.1 (OCH3), 55.7 (C), 54.7 (CH2), 52.5 (OCH3), 52.5 (CH2),
52.5 (C), 50.6 (CH2), 50.3 (CH2), 46.2 (CH2), 45.3 (CH2), 42.6 (C),
39.4 (CH3), 34.7 (CH2), 33.2 (CH), 31.9 (CH2), 28.0 (CH2), 26.1 (CH2),
21.2 (CH3), 12.6 (CH3), 8.5 (CH3); ESIMS m/z 805.4 [M + 1]+;
HRESIMS m/z 805.4537 (calcd for C48H60N4O7, 805.4540).
Acknowledgment. Financial support by the Chinese National Natural
Science Foundation of China (NNSF; No. 30772638) and Chinese
National High-tech R&D Program (2006AA020602) is gratefully
acknowledged.
3-Demethoxycarbonyl-3-(propyloxy)methylanhydrovinblastine
1
(20b): [R]20 +60.2 (c 0.30, CHCl3); H NMR (300 MHz, CDCl3) δ
D
9.00 (1H, s), 8.02 (1H, s), 7.52 (1H, d, J ) 7.5 Hz), 7.14 (3H, m),
6.58 (1H, s), 6.16 (1H, s), 5.88 (1H, m), 5.86 (1H, dd, J ) 9.6, 4.5
Hz), 5.51 (1H, d, J ) 6.0 Hz), 5.45 (1H, d, J ) 9.6 Hz), 5.03 (1H, s),
3.83 (3H, s), 3.62 (3H, s), 3.01 (3H, s), 2.57 (1H, s), 2.18 (3H, s), 1.96
(2H, q, J ) 7.5 Hz), 1.43 (1H, m), 1.21 (1H, m), 1.01 (3H, t, J ) 7.5
Hz), 0.91 (3H, t, J ) 7.2 Hz), 0.82 (3H, t, J ) 7.2 Hz); 13C NMR (75
MHz, CDCl3) δ 175.1 (C), 171.3 (C), 158.0 (C), 153.9 (C), 140.1 (C),
135.2 (C), 131.3 (C), 129.9 (CH), 129.6 (C), 124.7 (CH), 124.1 (CH),
123.9 (CH), 123.8 (C), 122.4 (CH), 121.3 (C), 119.0 (CH), 118.5 (CH),
117.2 (C), 110.6 (CH), 94.5 (CH), 81.0 (CH), 77.7 (C), 76.8 (CH),
72.4 (CH2), 68.9 (CH2), 66.5 (CH), 56.0 (OCH3), 55.6 (C), 54.6 (CH2),
Supporting Information Available: 1H NMR spectra for com-
pounds 5b-22b. This material is available free of charge via the Internet
at http://pubs.acs.org.
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NP800284H