Synthesis and antitumor activity of non-prodrug water-soluble taxoid: 10-C-aminoalkylated docetaxel analogs

Article abstract of DOI:10.3987/COM-00-9051

To develop non-prodrugs of taxoids possessing satisfactory stability in vivo, high water solubility and potent antitumor activity, we prepared several 10-C-sec-aminoalkylated docetaxel analogs and evaluated their cytotoxicity against mouse leukemia and hu

Full text of DOI:10.3987/COM-00-9051

HETEROCYCLES, Vol. 53, No12, 2000, pp. 2719 - 2737, Received, 1st September, 2000
SYNTHESIS AND ANTITUMOR ACTIVITY OF
NON-PRODRUG WATER-SOLUBLE TAXOID:
10-C-AMINOALKYLARED DOCETAXEL ANALOGS
Shin Iimura, Satoru Ohsuki, Jun Chiba, Kouichi Uoto, Michio Iwahana, Hirofumi
Terasawa, and Tsunehiko Soga*
New Product Research Laboratories IV, Daiichi Pharmaceutical Co., Ltd., 1-16-13,
Kitakasai, Edogawa, Tokyo 134-8630, Japan
Abstract-To develop non-prodrugs of taxoids possessing satisfactory stability in
vivo, high water solubility and potent antitumor activity, we prepared several 10-
C-sec-aminoalkylated docetaxel analogs and evaluated their cytotoxicity against
mouse leukemia and human tumor cell lines. These analogs were synthesized
from a 10-deacetoxy-10-C-formylethyl baccatin derivative. Among these
analogs, the 10-C-morpholinoethyl and 10-C-morpholinomethyl analogs exhibited
cytotoxicity comparable or superior to that of docetaxel.
Paclitaxel (1, Taxol®),1 which was originally isolated from Pacific yew Taxus brevifolia, has been used
clinically for the treatment of ovarian and breast cancers, and has shown significant beneficial effects.
On the other hand, docetaxel (2, Taxotere®),2 a semisynthetic analog of paclitaxel, has been used most
often for the treatment of breast and lung cancers. These two drugs are currently considered to be the
most important drugs in cancer chemotherapy.
However, their low water solubility requires that they
should be co-injected with a detergent, Cremophor® EL or Tween® 80.
Figure 1
R2
O
OH
O
O
10
1
7
R1
NH O
13
3'
O
O
H
2'
OAc
HO OBz
OH
Paclitaxel (1: R1 = Ph, R2 = Ac), Docetaxel (2: R1 = t-BuO, R2 = H)

These detergents frequently cause untoward hypersensitivity reactions (hypotension, bronchospasm,
urticaria etc.), and patients receiving these drugs should be premedicated.3 Tosolvetheproblemof low
water solubility, several research groups have synthesized and evaluated water-soluble taxoids such as
esterase- or phosphatase-cleavable prodrugs.4
However, these prodrugs are liable to exhibit variable
efficacy because of variations in the enzymatic activity of patients. To resolve these problems, we have
already described the synthesis of 10-O-sec-aminoethyldocetaxel analogs,5 10-C- aminopropyldocetaxel
6
analogs and 10-C-carboxypropyldocetaxel analogs.
Among these analogs, 10-O-(2-
morpholinoethyl)docetaxel (3) and 10-O-(2-thiomorpholinoethyl)docetaxel (4) exhibited cytotoxicity
comparable or superior to that of docetaxel (2). In addition, the methanesulfonic acid salt of one of these
analogs showed good water solubility.5 On the other hand, 10-C-aminoalkyldocetaxel analog (5) and 10-
C-carboxypropyldocetaxel analog (6) exhibited considerably lower activity than docetaxel (2) (Table 1).
It was hypothesized that this decrease of activity was because of the presence of a functional group, in the
end of the 10-C alkyl group, that may serve as hydrogen bond donor. On the basis of this hypothesis and
the relationships between structures and activities of 10-O-sec-aminoethyldocetaxel analogs, 10-C-
alkyldocetaxel analogs with a secondary amino group at the end of the 10-C-alkyl side chain were
designed.
Furthermore, to examine the influence of the length of the 10-C alkyl chain within a
homologous series on the cytotoxic activity, the chain length was varied from one to three. Here we
report the synthesis and cytotoxicity of 10-C-sec-aminoalkyldocetaxel analogs, with from one to three
alkyl carbon bonds.
R
O
OH
X
10
1
7
BocNH O
13
2'
O
3'
Ph
O
H
OAc
HO OBz
OH
Table 1. Cytotoxicity of Water Soluble Docetaxel Analogs
Compound
X
R
Cytotoxic activity GI50 (ng/mL)a
P388
PC-6
1.13
4.79
2.54
236
PC-12
6.74
24.1
2.90
1520
1870
53.4
215
Docetaxel (2)
⎯
O
⎯
3
4
5
6
N
O
S
O
65.4
N
CH2
CH2
NH2
6820
>10000
COOH
934
a) Concentration that inhibited the growth of cells by 50% on 72 h continuous exposure for three cell lines
[mouse leukemia (P388), human lung cancer cell lines (PC-6, PC-12 )].

Chemistry: 10-Deoxy-10-morpholinopropyldocetaxel (12) was synthesized from10-deacetoxy-10-
hydroxypropyl-7-O-TES baccatin III (7)6 using protected β-phenylisoserine (10)7 as an ester side chain
precursor (Scheme 1).
Tosylation of the primary hydroxyl group in 7 and substitution with morpholine
Succeeding introduction of the
gave the 10-C-morpholinopropyl analog (9) in 82% yield.
phenylisoserine side chain and the removal of protective groups gave10-deoxy-10-C-(3-
morpholinopropyl) docetaxel (12).
Scheme 1
O
N
O
N
HO
O
OTES
O
O
OTES
OTES
c
b
O
Ph
O
O
O
O
H
HO
HO
H
H
OAc
HO OBz
BocN
O
OAc
a
OAc
HO OBz
HO OBz
9
7
8
11
O
N
O
O
OH
Ph
BocN
OH
d
O
BocNH
Ph
O
O
O
H
OAc
HO OBz
10
OH
12
Reagents and conditions: a) TsCl, triethylamine, dichloromethane, 0 °C; b) morpholine, MeOH, reflux (82% from 7); c) 10,
dicyclohexylcarbodiimide, N,N-dimethylaminopyridine, dichloromethane (20%); d) 1) formic acid, rt; 2) tert-butoxycarbonyl
anhydride, THF (54% from 11).
Synthesis of sec-aminoethyl analogs (18a-h) is described in Scheme 2 and Table 2. The key
intermediate (17) for the synthesis of 10-C-aminoethyl analogs was synthesized from 8 (Scheme 2).
Scheme 2
TsO
Me
S
O
O
OTES
O
OTES
O
OTES
a
b
O
O
HO
O
H
HO
H
HO
H
OAc
HO OBz
OAc
OAc
HO OBz
HO OBz
14
8
13
TESO
Ph
OHC
O
O
OTES
NBoc
15
O
OTES
O
BocNH
Ph
O
BocNH
Ph
O
d
c
O
O
H
O
H
OAc
HO OBz
OAc
OTES
HO OBz
OTES
17
16
Reagents and conditions: a) 1) 50% aq. MeSNa (w/v), n-Bu4NI, THF, 0 °C, 2) NaIO4, MeOH-H2O, 0 °C (84%); b) K2CO3, 1,2-
dichlorobenzene, 170 °C (37%, net. 76%); c) 15, NaH, THF, 0 °C (91%); d) 1) OsO4, NMO, acetone-H2O, rt, 2) NaIO4,
MeOH-H2O (84%).

The reaction of 10-deacetoxy-7-O-TES-10-tosyloxypropylbaccatin III (8) with MeSNa followed by
oxidation with NaIO4 gave the sulfoxide (13) in high yield. The sulfoxide (13) was heated with K2CO3
to give olefin (14). A phenylisoserine side chain was introduced into the baccatin moiety using the β-
lactam to give 16 in high yield.8 Oxidation of 16 with OsO4 followed by cleavage with NaIO4 gave the
aldehyde (17) in high yield. Finally, compound (17) was subjected to reductive amination9 with various
sec-amines followed by standard desilylation to give the 10-C-sec-aminoethyl-10-deoxydocetaxel analogs
(18a-h, Table 2).
R
O
OH
method a or b
BocNH
Ph
O
17
O
O
H
OAc
OHOBz
OH
18a-h
Table 2. Synthesis of Aminoethyl Analogs by Reductive Amination.
entry
1
Compound
R
yield (%)
91
method*
a
N
O
S
18a
2
3
4
5
6
7
8
18b
18c
18d
18e
18f
52
65
39
39
26
59
83
b
a
a
a
a
b
b
N
N
N
N
NMe
N
18g
18h
N
N
O
*: method a: 1) amine, 5% Pd-C in MeOH under H2 gas, 2) HF-Py. method b: 1) amine, NaBH3CN, AcOH,
2) HF-Py.
To improve olefination from 7 to 14, we examined oxidative olefination of selenide (Scheme 3)10. An o-
nitrophenylselenyl group was introduced at the end of the 10-C alkyl group using o-nitrophenylselenyl
cyanide with n-tributylphosphine. The resulting selenide (19) was oxidized with m-chloroperbenzoic
acid to give the desired 14 in high yield. This method improved the yield, and reduced the number of
reaction steps required.

Scheme 3
HO
O
OTES
O
OTES
4 steps
40%
O
HO
O
H
HO
H
OAc
HO OBz
OAc
HO OBz
7
14
m-CPBA
o-NO PhSeCN,
2
O2N
Se
80% from7
n-Bu3P
O
OTES
O
HO
H
OAc
HO OBz
19
Synthesis of sec-aminomethyl analog (29) is described in Scheme 4. The hydroxy group at position 13
of 14 was protected with a TES group, and the resulting olefin was transformed to the aldehyde by
Johnson-Remeiux reaction.11 Succeeding hydrogenation of the aldehyde (20) with NaBH4 and the
subsequent terminal olefination described above gave 10-C-vinyl intermediate (23).
Reductive
amination of 24, removal of 7-O- and 13-O-TES, and re-introduction of TES to 7-hydroxy group afforded
26. Finally, introduction of a phenylisoserine side chain to 13-hydroxy group and removal of the
protecting groups, 2'-O-TBDMS and 7-O-TES, by hydrogen fluoride pyridine complex gave the desired
10-deoxy-10-C-morpholinomethyldocetaxel (29) (Scheme 4).
Scheme 4
HO
O
OHC
O
O
OTES
OTES
OTES
a
b
c
O
O
O
HO
TESO
TESO
H
H
H
OAc
OAc
OAc
HO OBz
HO OBz
HO OBz
21
14
20
Se
O
H
O
OHC
O
OTES
OTES
OTES
NO2
d
e
f
O
O
O
TESO
TESO
TESO
H
H
OAc
OAc
OAc
HO OBz
HO OBz
HO OBz
23
24
22
O
N
O
OTES
O
O
N
O
OTES
O
N
O
OTES
h
g
BocNH
Ph
O
O
O
TESO
H
O
HO
H
H
OAc
HO OBz
OAc
OAc
HO OBz
HO OBz
OTBS
25
26
28

O
O
N
O
OH
O
BocN
27
i
BocNH
Ph
OTBS
O
O
H
OAc
HO OBz
OH
29
Reagents and conditions: a) 1) TESCl, imidazole, DMF, 2) OsO4, NMO, MeOH-THF-H2O, 3) NaIO4,MeOH-THF-H2O (54%);
b) NaBH4, MeOH (96%); c) o-nitrophenylseleno cyanide, n-tributylphosphine, THF (92%); d) m-chloroperbenzoic acid,
CH2Cl2 (79%); e) 1) OsO4, NMO, MeOH-THF-H2O, 2) NaIO4, MeOH-THF-H2O (96%); f) morpholine, NaBH3CN, AcOH,
EtOH (82%); g) 1) hydrogen fluoride pyridine complex, Py, 2) TESCl, imidazole, DMF (32%); h) 27, NaHMDS, THF (49%);
i) hydrogen fluoride pyridine complex, Py (100%).
Results (Biological Activity) and Discussion: Cytotoxicities of the 10-C-sec-aminoalkyl-10-
deoxydocetaxel analogs against 7 cell lines (P388, PC-6, PC-12, SBC-3, SBC-3/ADM, PC-6/VCR29-9,11
PC-6/VP)12 in vitro were examined (Table 3).
( )n
R
O
OH
BocNH O
O
Ph
O
H
OAc
OHOBz
OH
Table 3. Cytotoxicity of 10-C-sec-Aminoalkylated Docetaxel Analogs.
Cytotoxic activity GI50 (ng/mL)a
n
R
P388 PC-6 PC-12 SBC-3 SBC-3/ADM10 PC-6/VCR29-9
PC-6/
VP1-1
820
6.7
1.1
53.4
432
0.5
19.5
1.1
280
>1000
51.6
262
135
NT
2
12
⎯
3
⎯
N
O
O
S
20.6 5.5
NT
779
NT
NT
N
N
2
3.1
3.1
0.6
4.8
1.2
13.5
32.9
299
76.3
NT
18a
18b
18c
2
3.0
2
17.3
NT
NT
NT
N
2
2
N
3.8
5.8
1.4
2.0
193.5
293
3.0
5.2
441
755
NT
NT
NT
NT
18d
18e
N
NMe
2
2
2
11.2 1.8
414
91.2
5.6
7.2
NT*
NT
1003
NT
NT
916
79.6
NT
>1000
676
18f
18g
18h
N
3.6
1.1
2.7
1.3
N
NT
N
O
N
O
1
1.2
1.2
3.3
NT
NT
62.0
220
29
a) Concentration that inhibited the growth of cells by 50% on 72 h continuous exposure for the seven cell lines [mouse
leukemia (P388), human lung cancer cell lines (PC-6, PC-12, SBC-3), and resistant cancer cell lines (PC-6/ VCR29-9, SBC-
3/ADM10, PC-6/VP1-1)].13 *: NT: not tested.
Cytotoxicity of 12, which has a morpholinopropyl group at the C-10 position, was improved compared

with 10-C-aminopropyldocetaxel (5), but the activity was lower than that of docetaxel. However, some
sec-aminoethyl analogs showed potent activity similar to that of docetaxel against four cancer cell lines
and three resistant cancer cell lines. Morpholinoethyl analogs, (18a) and (18h), showed the strongest
activity among the sec-aminoethyl analogs. Comparison of the activities of 18a-h clarified two things.
Firstly, there is spatial margin around 10-C position. Secondly, electronic and conformational factors
affected the activity. The morpholinomethyl analog (29) showed the most potent activity among these
aminoalkyl analogs. This result indicated that the chain length of the aminoalkyl group greatly
influences the potency of activity. In comparison of the 10-O-morpholinoethyl analog (3) with 12, the
cytotoxicity of the ether type was slightly stronger than that of the alkyl type. Shortening of the chain
length markedly improved the cytotoxicity (compare activities of 2 vs. 18a, and 18a vs. 29). This result
indicated that the alkyl type is superior to the ether type, because shortening of the 10-O-aminoalkyl chain
has a limitation.
In conclusion, several 10-C-sec-aminoalkyl-10-deoxydocetaxel analogs exhibited cytotoxicity comparable
or superior to that of docetaxel (2). Further investigation into the in vivo antitumor activities of these
analogs are currently underway in our laboratory and will be reported in the near future.
EXPERIMENTAL
General Procedures: All melting points were found using a Yanaco PM-S3 or MP-500D apparatus and
we are not corrected. IR spectra were obtained on a Hitachi 270-300 IR spectrophotometer. Ms spectra
were recorded on a JEOL JMS-HX-100, AX505W, JMS-D300 or JMS-700 spectrometer. 1H-NMR
spectra were taken at 400 MHz with a JEOL JNM-EX400 spectrometer; all values are reported in ppm (δ)
downfield from (CH3)4Si. Elemental analyses were performed on a Heraeus CHN-O-Rapid or a Perkin-
Elmer 2400CHN instrument. Optical rotations were measured with a Horiba SEPA-200 polarimeter.
Merck silica gel (230-400 mesh) was used for column chromatography. Thin layer chromatography
(TLC) was performed using silica gel (150A 1.0 mm thickness; PLK5F Whatman).
[10R]-10-Deacetoxy-(3-p-toluenesulfonyloxypropyl)-7-O-triethylsilylbaccatin III (8)
To a stirred solution of 7 (300 mg, 0.428 mmol) in dichloromethane (10 mL) were added p-
toluenesulfonyl chloride (245 mg, 1.28 mmol), triethylamine (130 mg, 1.28 mmol) and a catalytic amount
of N,N-dimethylaminopyridine at 0 °C. Stirring was continued for 18 h at ambient temperature. The
mixture was poured into ice-water and extracted with chloroform. The combined organic phase was
washed with brine, dried over anhydrous MgSO4 and concentrated under reduced pressure. The residue
was chromatographed on silica gel (3% MeOH/CHCl3) to give compound (8) (360 mg, quant.) as a
colorless oil; 1H-NMR (CDCl3) δ 0.52 (m, 6H), 0.92 (t, 9H, J = 8 Hz), 1.00 (s, 3H), 1.04 (s, 3H), 1.60 (s,
3H), 1.92 (s, 3H), 2.28 (s, 3H), 2.46 (s, 3H), 3.73⎯3.77 (m, 1H), 4.00⎯4.10 (m, 3H), 4.15 (d, 1H, J = 8

Hz), 4.29 (d, 1H, J = 8 Hz), 4.49⎯4.55 (m, 1H), 4.80⎯4.88 (br, 1H), 4.95 (d, 1H, J = 10 Hz), 5.57 (d, 1H,
J = 7 Hz), 7.36 (d, 2H, J = 8 Hz), 7.47 (t, 2H, J = 7 Hz), 7.60 (t, 1H, J = 7 Hz), 8.10 (d, 2H, J = 7 Hz); MS
(FAB) m/z: 856 (MH+).
10-Deacetoxy-10-(3-morpholinopropyl)-7-O-triethylsilylbaccatin III (9)
To a stirred solution of 8 (100 mg, 0.117 mmol) in MeOH (2 mL) was added morpholine (51 mg, 0.59
mmol) at ambient temperature. The mixture was refluxed for 5 h. The solvent was removed under
reduced pressure, and the residue was purified by TLC (10% MeOH/CHCl3) to give compound (9) (74 mg,
82%) as a colorless oil; 1H-NMR (CDCl3) δ 0.50⎯0.61 (m, 6H), 0.95 (t, 9H, J = 8 Hz), 1.04 (s, 3H), 1.11
(s, 3H), 1.45⎯2.51 (m, 23H), 3.72 (t, 4H, J = 5 Hz), 3.81 (dd, 1H, J = 9 Hz, 5 Hz), 4.05 (d, 1H, J = 7 Hz),
4.16 (d, 1H, J = 8 Hz), 4.29 (d, 1H, J = 8 Hz), 4.54 (dd, 1H, J = 11 Hz, 7 Hz), 4.80⎯4.85 (m, 1H), 4.96
(d, 1H, J = 8 Hz), 5.59 (d, 1H, J = 7 Hz), 7.47 (t, 2H, J = 8 Hz), 7.59 (t, 1H, J = 8 Hz), 8.10 (d, 2H, J = 8
Hz); MS (FAB) m/z: 770 (MH+).
[2'R,3'S]-13-O-(N-tert-Butoxycarbonyl-N,O-isopropylidene-3-phenylisoserinyl)-10-deacetoxy-10-(3-
morpholinopropyl)-7-O-triethylsilylbaccatin III (11)
To a stirred solution of 9 (43.5 mg, 0.057 mmol) and 10 (36.3 mg, 0.113 mmol) in toluene (2 mL) was
added dicyclohexylcarbodiimide (23 mg, 0.113 mmol) at 0 °C. Stirring was continued for 15 min at the
same temperature, then N,N-dimethylaminopyridine (7 mg) was added to the reaction at ambient
temperature. Stirring was continued for 3 h. The mixture was diluted with ethyl acetate, washed with
sat. NaHCO3 and brine, dried over anhydrous MgSO4 and concentrated under reduced pressure. The
residue was purified by TLC (3% MeOH/CHCl3) to give compound (11) (12 mg, 20%) as a colorless oil;
1H-NMR (CDCl3) δ 0.48 (m, 6H), 0.93 (t, 9H, J = 8 Hz), 1.05⎯1.50 (m, 5H), 1.13 (s, 3H), 1.20 (s, 3H),
1.59 (s, 3H), 1.67 (s, 9H), 1.77⎯1.98 (m, 2H), 1.77 (s, 3H), 1.79 (s, 3H), 1.82 (s, 3H), 2.08⎯2.16 (m,
3H), 2.30⎯2.48 (m, 5H), 3.70⎯3.80 (m, 5H), 3.92 (d, 1H, J = 7 Hz), 4.06 (d, 1H, J = 7 Hz), 4.11 (d, 1H,
J = 8 Hz), 4.23 (d, 1H, J = 8 Hz), 4.44⎯4.50 (m, 1H), 4.47 (m, 1H), 4.88 (d, 1H, J = 8 Hz), 5.04 (br, 1H),
5.62 (d, 1H, J = 7 Hz), 6.24 (t, 1H, J = 8 Hz), 7.30⎯7.41 (m, 5H), 7.50 (t, 2H, J = 7 Hz), 7.63 (t, 1H, J =
7 Hz), 8.05 (d, 2H, J = 7 Hz); MS (FAB) m/z: 1073 (MH+).
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-[3-
(morpholinopropyl)]baccatin III (12)
Compound (11) (10 mg, 10 µmol) was dissolved in formic acid (2 mL) and the mixture was stirred for 30
min at ambient temperature. The mixture was concentrated under reduced pressure, and the residue was
dissolved in CHCl3, washed with sat. NaHCO3 and brine, dried over anhydrous MgSO4 and concentrated
under reduced pressure. The residue was dissolved in THF (2 mL) and (Boc)2O (15 mg, 0.069 mmol)
was added. Stirring was continued for 18 h. The mixture was concentrated under reduced pressure,

and the residue was purified by TLC (3% MeOH/CHCl3) and freeze-dried to give compound (12) (5 mg,
24
54%) as a white solid; [α]D -69.8° (c = 0.12, CHCl3); IR (KBr): 3455, 2980, 1980, 1716, 1608 (cm-1);
1H-NMR (CDCl3) δ 0.48⎯0.56 (m, 6H), 0.93 (t, 9H, J = 8 Hz), 1.05⎯1.50 (m, 5H), 1.13 (s, 3H), 1.20 (s,
3H), 1.59 (s, 3H), 1.67 (s, 9H), 1.77⎯1.98 (m, 2H), 1.78 (s, 3H), 1.79 (s, 3H), 1.82 (s, 3H), 2.08⎯2.16
(m, 3H), 2.30⎯2.48 (m, 5H), 3.70⎯3.80 (m, 5H), 3.92 (d, 1H, J = 7 Hz), 4.06 (d, 1H, J = 7 Hz), 4.11 (d,
1H, J = 8 Hz), 4.23 (d, 1H, J = 8 Hz), 4.44⎯4.50 (m, 1H), 4.47 (m, 1H), 4.88 (d, 1H, J = 8 Hz), 5.04 (br,
1H), 5.62 (d, 1H, J = 7 Hz), 6.24 (t, 1H, J = 7 Hz), 7.30⎯7.41 (m, 5H), 7.50 (t, 2H, J = 7 Hz), 7.63 (t, 1H,
J = 7 Hz), 8 05 (d, 2H, J = 7 Hz); MS (FAB) m/z: 919 (MH+); Anal. Calcd for C50H66N2O14・1.5H2O; C,
63.48; H, 7.35; N, 2.96. Found: C, 63.21; H, 7.22; N, 2.90.
10-Deacetoxy-10-(3-methanesulfinylpropyl)-7-O-triethylsilylbaccatin III (13)
To a cooled and stirred solution of 8 (425 mg, 0.50 mmol) in THF (5 mL) were added NaSMe solution in
H2O (50% w/v, 2.3 mL, 16.4 mmol) and n-Bu4NI (127 mg, 0.34 mmol). Stirring was continued for 6 h
at ambient temperature. The mixture was diluted with ethyl acetate (100 mL), washed with H2O and
brine, and dried over anhydrous MgSO4. After removal of the solvent under reduced pressure, the
residue was chromatographed on silica gel (CHCl3/n-hexane/acetone, 14:5:1) to give 10-deacetyl-10-(3-
methylthiopropyl)-7-O-triethylsilylbaccatin III (332 mg). The compound was dissolved in MeOH (7
mL) and was added to a solution of NaIO4 (150 mg, 0.70 mmol) in H2O (3.5 mL) at 0 °C. Stirring was
continued for 2 h at 0 °C. The mixture was diluted with ethyl acetate (100 mL), washed with H2O and
brine, and dried over anhydrous MgSO4. After removal of the solvent under reduced pressure, the
residue was purified by TLC (6% MeOH/CHCl3) to give compound (13) (312 mg, 84%) as a colorless oil;
IR (KBr): 3455, 2980, 1980, 1716, 1608 (cm-1); 1H-NMR (CDCl3) δ 0.55 (m, 6H), 0.95 (t, 9H, J = 8 Hz),
1.06, 1.08, 1.10 and 1.11 (each s, total 6H), 1.63 (s, 3H), 1.98 (s, 3H), 2.29 (s, 3H), 1.70⎯2.35 (m, 6H),
2.50 (m, 1H), 2.59 (s, 3H), 2.60⎯2.90 (m, 3H), 3.86 (dd, 1H, J = 10 Hz, 5 Hz), 4.04 (d, 1H, J = 7 Hz),
4.16 (d, 1H, J = 8 Hz), 4.30 (d, 1H, J = 8 Hz), 4.55 (dd, 1H, J = 10 Hz, 6 Hz), 4.85 (br, 1 H), 4.97 (d, 1H,
J = 8 Hz), 5.60 (d, 1H, J = 7 Hz), 7.47 (t, 2H, J = 7 Hz), 8.11 (d, 2H, J = 7 Hz); MS (FAB) m/z: 747
(MH+).
10-Allyl-10-deacetoxy-7-O-triethylsilylbaccatin III (14)
To a stirred solution of 13 (294 mg, 0.39 mmol) in o-dichlorobenzene (20 mL) was added Na2CO3 (42 mg,
0.39 mmol). The mixture was refluxed for 4 h. The insoluble material was filtered off and the filtrate
was concentrated under reduced pressure. The residue was purified by TLC (CHCl3/n-hexane/acetone,
24
7:2:1) and freeze-dried to give compound (14) (100 mg, 37%) as a colorless powder; [α]D -55.8° (c =
0.50, CHCl3); IR (KBr): 3475, 2970, 1980, 1720 (cm-1); 1H-NMR (CDCl3) δ 0.57 (m, 6H), 0.96 (t, 9H, J=
8 Hz), 1.13 (s, 3H), 1.18 (s, 3H), 1.63 (s, 3H), 1.89 (m, 1H), 1.93 (d, 3H, J = 1 Hz), 2.15⎯2.35 (m, 2H),

2.29 (s, 3H), 2.40⎯2.60 (m, 2H), 2.80 (m, 1H), 3.90 (dd, 1H, J = 10 Hz, 4 Hz), 4.05 (d, 1H, J = 7 Hz),
4.17 (d, 1H, J = 8 Hz), 4.30 (d, 1H, J = 8 Hz), 4.54 (dd, 1H, J = 11 Hz, 7 Hz), 4.85 (br, 1H), 4.96 (dd, 1H,
J = 10 Hz, 2 Hz), 5.01 (d, 1H, J = 10 Hz), 5.09 (d, 1H, J = 16 Hz), 5.61 (d, 1H, J = 7 Hz), 5.79 (ddt, J =
16 Hz, 10 Hz, 7 Hz, 1H), 7.47 (t, 2H, J = 7 Hz), 7.60 (t, 1H, J = 7 Hz), 8.11 (d, 2H, J = 7 Hz); MS (FAB)
m/z: 683 (MH+); Anal. Calcd for C38H54O9Si: C, 66.83; H, 7.97. Found: C, 66.85; H, 8.05.
[2'R,3'S]-10-Allyl-13-O-(3-tert-butoxycarbonylamino-2-O-triethylsilyl-3-phenylisoserinyl)-10-
deacetoxy-7-O-triethylsilylbaccatin III (16)
To a stirred suspension of NaH (100 mg, 2.5 mmol, 60% oil suspension) in THF (1.5 mL) were added 14
(100 mg, 0.15 mmol) and 15 (110 mg, 0.29 mmol) in THF (1.5 mL) at 0 °C. Stirring was continued for
2 h at 0 °C. The mixture was poured into sat. NH4Cl, and extracted with ethyl acetate. The combined
organic phase was washed with brine and dried over anhydrous MgSO4. After removal of the solvent
under reduced pressure, the residue was purified by TLC (CHCl3/n-hexane/acetone, 10:9:1) to give
compound (16) (141 mg, 91%) as a colorless oil; 1H-NMR (CDCl3) δ 0.38 (m, 6H), 0.57 (m, 6H), 0.78 (t,
9H, J = 8 Hz), 0.96 (m, 9H), 1.16 (s, 3H), 1.25 (s, 3H), 1.30 (s, 9H), 1.64 (s, 3H), 1.76 (s, 3H), 1.91 (m,
1H), 2.13 (m, 1H), 2.38 (m, 1H), 2.45⎯2.55 (m, 1H), 2.48 (m, 1H), 2.52 (s, 3H), 2.84 (m, 1H), 3.84 (dd,
1H, J = 10 Hz, 4 Hz), 3.99 (d, 1 H, J = 7 Hz), 4.21 (d, 1H, J = 8 Hz), 4.31 (d, 1H, J = 8 Hz), 4.52 (dd, 1H,
J = 11 Hz, 7 Hz), 4.54 (br, 1H), 4.96 (dd, 1H, J = 10 Hz, 2 Hz), 5.04 (d, 1H, J = 10 Hz), 5.10 (d, 1H, J =
17 Hz), 5.39 (br, 1H), 5.49 (br, 1H), 5.67 (d, 1H, J = 7 Hz), 5.78 (m, 1H), 6.26 (t, 1H, J = 9 Hz),
7.20⎯7.40 (m, 5 H), 7.48 (t, 2H, J = 7 Hz), 7.58 (t, 1H, J = 7 Hz), 8.12 (d, 2H, J = 7 Hz); MS (FAB) m/z:
1061 (MH+).
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-2-O-triethylsilyl-3-phenylisoserinyl)-10-deacetoxy-10-
formylmethyl-7-O-triethylsilylbaccatin III (17)
To a stirred solution of 16 (141 mg, 0.13 mmol) in THF/H2O (3.6 mL, 5:1, v/v) were added N-
methylmorpholine N-oxide (24 mg, 0.20 mmol) and a catalytic amount of OsO4. Stirring was continued
for 2 h at ambient temperature. The mixture was poured into 10% Na2S2O3, and extracted with ethyl
acetate.
The combined organic phase was washed with sat. NaHCO3 and brine, dried over anhydrous
MgSO4, and concentrated under reduced pressure. The residue was dissolved in THF/H2O (12 mL, 1:1,
v/v) and NaIO4 (150 mg, 0.70 mmol) was added . After stirring for 24 h at ambient temperature, the
mixture was poured into H2O, and extracted with ethyl acetate.
The combined organic phase was
washed with sat. NaHCO3 and brine, dried over anhydrous MgSO4, and concentrated under reduced
pressure. The residue was purified by TLC (CHCl3/n-hexane/acetone, 14:5:1) and freeze-dried from
dioxane to give compound (17) (119 mg, 84%) as a colorless powder; [α]D24 -25.0° (c = 0.55, CHCl3); IR
(KBr): 3452, 2960, 1755, 1720 (cm-1); 1H-NMR (CDCl3) δ 0.39 (m, 6H), 0.57 (m, 6H), 0.78 (t, 9H, J = 8
Hz), 0.94 (t, 9H, J = 8 Hz), 1.13 (s, 3H), 1.24 (s, 3H), 1.29 (s, 9H), 1.66 (s, 3H), 1.88 (s, 3H), 1.92 (m,

1H), 2.15 (m, 1H), 2.38 (m, 1H), 2.45⎯2.62 (m, 2H), 2.53 (s, 3H), 3.59 (dd, 1H, J = 17 Hz, 6 Hz), 4.00
(d, 1H, J = 7 Hz), 4.20 (d, 1H, J = 8 Hz), 4.32 (d, 1H, J = 8 Hz), 4.49 (t, 1H, J = 6 Hz), 4.54 (br, 1H), 4.59
(dd, 1H, J = 11 Hz, 7 Hz), 4.97 (dd, 1H, J = 10 Hz, 2 Hz), 5.29 (br, 1H), 5.48 (br, 1H), 5.68 (d, 1H, J = 7
Hz), 6.21 (t, 1H, J = 10 Hz), 7.22⎯7.37 (m, 5H), 7.48 (t, 2H, J = 7 Hz), 7.58 (t, 1H, J = 7 Hz), 8.12 (d,
2H, J = 7 Hz), 9 79 (s, 1H); MS (FAB) m/z: 1063 (MH+); Anal. Calcd for C57H83NO14Si･H2O: C, 63.36; H,
7.93; N, 1.30. Found: C, 63.27; H, 7.82; N, 1.22.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-(2-
morpholinoethyl)baccatin III (18a)
To a stirred solution of 17 (9 mg, 8.5 µmol) in MeOH (1.0 mL) were added morpholine (10 µL, 0.083
mmol) and 10% Pd on carbon (25 mg, 50% w/w, wet). Stirring was continued for 3 h under H2 gas at
ambient temperature. The insoluble material was filtered off, and the solvent was removed under
reduced pressure. The residue was dissolved in pyridine (1 mL), and hydrogen fluoride pyridine
complex (0.2 mL, 0.14 mmol) was added at 0 °C. The reaction was stirred for 12 h at ambient
temperature. The mixture was diluted with ethyl acetate and was washed with water and sat. NaHCO3,
dried over anhydrous MgSO4, and concentrated under reduced pressure. The residue was purified by
TLC (6% MeOH/CHCl3) and freeze-dried from dioxane to give compound (18a) (7 mg, 91%) as a
24
colorless powder; [α]D -55.8° (c = 0.15, CHCl3); IR (KBr): 3455, 2974, 1982, 1716, 1610 (cm-1); 1H-
NMR (CDCl3) δ 1.11 (s, 3H), 1.21 (s, 3H), 1.39 (s, 9H), 1.45⎯1.55 (m, 1H), 1.62 (s, 3H), 1.70⎯1.95 (m,
2H), 1.78 (s, 3H), 2.38 (s, 3H), 2.15⎯2.75 (m, 9H), 3.68 (m, 4H), 3.94 (d, 1H, J = 7 Hz), 4.01 (dd, 1H, J
= 9 Hz, 2 Hz), 4.19 (d, 1H, J = 8 Hz), 4.30 (d, 1H, J = 8 Hz), 4.44 (dd, 1H, J = 11 Hz, 6 Hz), 4.60 (br, 1H),
5.00 (dd, 1H, J = 10 Hz, 2 Hz), 5.27 (d, 1H, J = 9 Hz), 5 37 (d, 1H, J = 9 Hz), 5.64 (d, 1H, J = 7 Hz), 6.17
(d, 1H, J = 9 Hz), 7.32⎯7.44 (m, 5H), 7.50 (t, 2H, J = 7 Hz), 7.61 (t, 1H, J = 7 Hz), 8.11 (d, 2H, J = 7
Hz); MS (FAB) m/z: 905 (MH+); Anal. Calcd for C49H64N2O14･H2O: C, 63.76; H, 7.20; N, 3.03. Found:
C, 63.47; H, 7.32; N, 2.92.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-(2-
thiomorpholinoethyl)baccatin III (18b)
To a stirred solution of 17 (17 mg, 16 µmol) in EtOH (1.0 mL) were added thiomorpholine (16 µL, 0.16
mmol), AcOH (9.2 µl, 0.16 mmol) and NaBH3CN (10 mg, 0.16 mmol). Stirring was continued for 1.5 h
at ambient temperature. The mixture was diluted with ethyl acetate, poured into sat. NaHCO3,
extracted with ethyl acetate, and dried over anhydrous MgSO4. After removal of the solvent, the residue
was purified by TLC (5% acetone/CHCl3). The purified compound was dissolved in pyridine (1 mL),
and hydrogen fluoride pyridine complex (0.2 mL, 0.14 mmol) was added at 0 °C. The reaction was
stirred for 18 h at ambient temperature. The mixture was diluted with ethyl acetate, washed with water

and sat. NaHCO3, dried over anhydrous MgSO4, and concentrated under reduced pressure. The residue
was purified by TLC (3% MeOH/CHCl3) and freeze-dried from dioxane to give compound (18b) (8 mg,
52%) as a colorless powder; [α]D24 -59.5° (c = 0.1, CHCl3); IR (KBr): 3448, 2976, 1982, 1714, 1608(cm-
1); H-NMR (CDCl3) δ 1.09 (s, 3H), 1.21 (s, 3H), 1.32 (s, 9H), 1.62 (s, 3H), 1.78 (s, 3H), 1.87 (m, 1H),
1
2.19 (m, 1H), 2.36 (m, 5H), 2.37 (s, 3H), 2.49 (m, 1H), 2.68 (m, 6H), 2.78 (m, 2H), 3.94 (d, 1H, J = 7 Hz),
4.19 (d, 1H, J = 8 Hz), 4.29 (d, 1H, J = 8 Hz), 4.42 (dd, 1H, J = 11 Hz, 7 Hz), 4.60 (s, 1H), 4.98 (d, 1H, J
= 8 Hz), 5.24 (d, 1H, J = 9 Hz), 5.36 (d, 1H, J = 9 Hz), 5.62 (d, 1H, J = 6 Hz), 6.17 (t, 1H, J = 9 Hz),
7.31⎯7.37 (m, 5H), 7.47 (t, 2H, J = 7 Hz), 7.61 (t, 1H, J = 7 Hz), 8.11 (d, 2H, J = 7 Hz); MS (FAB) m/z:
921 (MH+); Anal. Calcd for C49H64N2O13S･2H2O: C, 61.49; H, 7.16; N, 2.93. Found: C, 61.20; H, 6.99;
N, 2.63.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-(2-N,N-
dimethylaminoethyl)baccatin III (18c) was prepared by a method similar to that described for
preparation of 18a by reaction of aldehyde (17) with N, N-dimethylamine and removal of the protecting
group with hydrogen fluoride pyridine complex. 18c was attained as a colorless powder (65%); 1H-NMR
(CDCl3) δ 1.09 (s, 3H), 1.11 (s, 3H), 1.36 (S, 9H), 1.61 (m, 1H), 1.65 (s, 3H), 1.70 (m, 3H), 1.82 (m, 1H),
2.04 (s, 6H), 2.15 (m, 1H), 2.32 (s, 3H), 2.38⎯2.53 (m, 3H), 2.78 (dd, J = 14 Hz, 9 Hz, 1H), 3.33 (br s,
4H), 3.58 (m, 1H), 3.80 (d, J = 7 Hz, 1H), 4.16 (dd, J = 9 Hz, 1 Hz, 1H), 4.28⎯4.30 (m, 2H), 4.57 (d, J =
3 Hz), 4.90 (t, J = 8 Hz, 1H), 5.24 (m, 1H), 5.67 (d, J = 7 Hz, 1H), 5.97 (m, 1H), 7.40 (m, 3H), 7.47 (m,
2H), 7.58 (m, 1H), 8.03 (m, 1H), 8.06 (m, 1H); MS (FAB) m/z: 863 (MH+); HR-MS Calcd for
C47H63N2O13 : 863.4330. Found: 863.4371.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-(2-
piperidinylethyl)baccatin III (18d) was prepared by a method similar to that described for preparation of
18a by reaction of aldehyde (17) with piperidine and removal of the protecting group with hydrogen
1
fluoride pyridine complex. 18d was attained as a colorless powder (39%); H-NMR (CDCl3) δ 1.09 (s,
3H), 1.11 (s, 3H), 1.36 (S, 9H), 1.42⎯1.50 (m, 6H), 1.61 (m, 1H), 1.65 (s, 3H), 1.70 (m, 3H), 1.82 (m,
1H), 2.22 (m, 2H), 2.30 (m, 2H), 2.32 (s, 3H), 2.38⎯2.53 (m, 5H), 2.78 (dd, J = 14 Hz, 9 Hz, 1H), 3.33
(brs, 4H), 3.58 (m, 1H), 3.80 (d, J = 7 Hz, 1H), 4.16 (dd, J = 9 Hz, 1 Hz, 1H), 4.28⎯4.30 (m, 2H), 4.57 (d,
J = 3 Hz), 4.90 (t, J = 8 Hz, 1H), 5.24 (m, 1H), 5.67 (d, J = 7 Hz, 1H), 5.97 (m, 1H), 7.40 (m, 3H), 7.47
(m, 2H), 7.58 (m, 1H), 8.03 (m, 1H), 8.06 (m, 1H); MS (FAB) m/z: 903 (MH+); HR-MS Calcd for
C50H67N2O13 : 903.4643. Found: 903.4656.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-[2-(4-N-methyl-1-
piperadinyl)ethyl]baccatin III (18e) was prepared by a method similar to that described for preparation
of 18a by reaction of aldehyde (17) with N-methylpiperazine and removal of the protecting group with

hydrogen fluoride pyridine complex. 18e was attained as a colorless powder (39%); 1H-NMR (CDCl3) δ
1.09 (s, 3H), 1.11 (s, 3H), 1.36 (S, 9H), 1.58 (m, 1H), 1.65 (s, 3H), 1.70 (s, 3H), 1.78 (m, 1H), 2.23 (s,
3H), 2.32 (s, 3H), 2.35⎯2.53 (m, 12H), 2.78 (dd, J = 14 Hz, 9 Hz, 1H), 3.33 (br, 4H), 3.58 (m, 1H), 3.80
(d, J = 7 Hz, 1H), 4.16 (dd, J = 9 Hz, 1 Hz, 1H), 4.28⎯4.30 (m, 2H), 4.57 (d, J = 3 Hz), 4.90 (t, J = 8 Hz,
1H), 5.24 (m, 1H), 5.67 (d, J = 7 Hz, 1H), 5.97 (m, 1H), 7.40 (m, 3H), 7.47 (m, 2H), 7.58 (m, 1H), 8.03
(m, 1H), 8.06 (m, 1H); MS (FAB) m/z: 918 (MH+); HR-MS Calcd for C50H68N3O13 : 918.4752. Found,
918.4747.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-[2-(1-
pyrrolidinyl)ethyl]baccatin III (18f) was prepared by a method similar to that described for preparation
of 18a by reaction of aldehyde (17) with pyrrolidine and removal of the protecting group with hydrogen
fluoride pyridine complex. 18f was attained as a colorless powder (26%); 1H-NMR (CDCl3) δ 1.09 (s,
3H, 17-Me), 1.11 (s, 3H, Me), 1.36 (S, 9H, t-Butyl), 1.61 (m, 1H, 10-CH2), 1.65 (s, 3H, 19-Me), 1.70 (s,
3H, 18-Me), 1.72 (m, 2H, CH2-pyrrolidine), 1.81 (m, 3H, CH2-pyrrolidine and 10-CH2), 2.32 (s, 3H,
acetyl), 2.38 (m, 1H, 6-CH2), 2.45⎯2.59 (m, 8H, 14-CH2, CH2-pyrrolidine, 10-CH2, and6-CH2), 2.78 (dd,
J = 14 Hz, 9 Hz, 1H, 14-CH2), 3.33 (brs, 4H, 1-OH, 7-OH, 2'-OH, and 3'-NH), 3.58 (m, 1H,10-CH), 3.80
(d, J = 7 Hz, 1H, 3-CH), 4.16 (dd, J = 9 Hz, 1 Hz, 1H, 20-CH2), 4.28⎯4.30 (m, 2H, 7-CH and 20-CH2),
4.57 (d, J = 3 Hz, 2'-CH), 4.90 (t, J = 8 Hz, 1H, 5-CH), 5.24 (m, 1H, 3'-CH), 5.67 (d, J = 7 Hz,1H,2-CH),
5.97 (m, 1H, 13-CH), 7.40 (m, 3H, 3'-Ph), 7.47 (m, 2H, 2'-Bz), 7.58 (m, 1H, 2'-Bz), 8.03 (m, 1H, 2'-Bz),
8.06 (m, 1H, 2'-Bz); MS (FAB) m/z: 889 (MH+); HR-MS Calcd for C49H65N2O13 : 889.4487. Found,
889.4506.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-[2-(1-
homopiperidinyl)ethyl]baccatin III (18g) was prepared by a method similar to that described for
preparation of 18b by reaction of aldehyde (17) with homopiperidine and removal of the protecting group
with hydrogen fluoride pyridine complex. 18g was attained as a colorless powder (59%); IR (KBr):
3668, 2936, 1962, 1714, 1606 (cm-1); 1H-NMR (CDCl3) δ 1.11 (s, 3H), 1.12 (s, 3H), 1.32 (brs, 9H), 1.62
(s, 3H), 1.68 (m, 6H), 1.87 (m, 5H), 1.88 (s, 3H), 2.20 (m, 1H), 2.30 (m, 2H), 2.37 (s, 3H), 2.49 (m, 1H),
2.60 (m, 1H), 2.90⎯3.10 (br, 6H), 3.52 (m, 1H), 3.95 (d, 1H, J = 7 Hz), 4.19 (d, 1H, J = 9 Hz), 4.23 (m,
1H), 4.28 (d, 1H, J = 9 Hz), 4.51 (dd, 1H, J = 11 Hz, 7 Hz), 4.60 (s, 1H), 4.96 (d, 1H, J = 8 Hz), 5.26 (m,
1H), 5.42 (m, 1H), 5.62 (d, 1H, J = 7 Hz), 6.17 (m, 1H), 7.31⎯7.38 (m, 5H), 7.49 (t, 2H, J = 8 Hz), 7.61
(t, 1H, J = 8 Hz), 8.13 (d, 2H, J = 8 Hz); MS (FAB) m/z: 915 (MH+); HR-MS Calcd for C51H69N2O13 :
917.4800. Found, 917.4835.
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-[2-(2,6-cis-
dimethyl-4-morpholyl)ethyl]baccatin III (18h) was prepared by a method similar to that described for

preparation of 18b by reaction of aldehyde (17) with 2,6-cis-dimethylmorpholine and removal of the
protecting group with hydrogen fluoride pyridine complex. 18h was attained as a colorless powder
(83%); IR (KBr): 3448, 2936, 2348, 1714, 1604 (cm-1); 1H-NMR (CDCl3) δ 1.11 (s, 3H), 1.16 (d, 1H, J =
7 Hz), 1.21 (s, 3H), 1.32 (s, 9H), 1.62 (s, 3H), 1.78 (m, 6H), 1.87 (m, 1H), 2.15⎯2.35 (m, 7H), 2.37 (m,
7H), 2.49 (m, 1H), 2.60 (m, 1H), 2.72⎯2.90 (m, 2H), 3.62 (m, 2H), 3.92 (d, 1H, J = 7 Hz), 4.00 (d, 1H, J
= 7 Hz), 4.19 (d, 1H, J = 9 Hz), 4.29 (d, 1H, J = 9 Hz), 4.42 (dd, 1H, J = 11 Hz, 7 Hz), 4.60 (s, 1H), 5.00
(d, 1H, J = 8 Hz), 5.28 (m, 1H), 5.38 (d, 1H, J = 9 Hz), 5.62 (d, 1H, J = 6 Hz), 6.18 (m, 1H), 7.31⎯7.42
(m, 5H), 7.49 (t, 2H, J = 8 Hz), 7.61 (t, 1H, J = 8 Hz), 8.11 (d, 2H, J = 8 Hz); MS (FAB) m/z: 933 (MH+);
HR-MS Calcd for C51H69N2O14 : 933.4749. Found, 933.4758.
10-Deacetoxy-10-[2-(o-nitrophenylselenyl)ethyl]-7-O-triethylsilylbaccatin III (19)
To a stirred solution of 7 (87 mg, 0.12 mmol) and o-nitrophenylselenocyanate (34 mg, 0.15 mmol) in THF
(2 mL) was added n-tributylphosphine (37 µL, 0.15 mmol) at 0 °C under N2 gas. Stirring was continued
for 2 h at ambient temperature. After removal of the solvent under reduced pressure, the residue was
purified by TLC (3% MeOH/CHCl3) to give 19 (80 mg, 73%) as a colorless solid; IR (KBr): 3508, 2884,
1
2340, 1970, 1710, 1454 (cm-1); H-NMR (CDCl3) δ 0.52 (m, 6H), 0.94 (t, 9H, J = 8 Hz), 1.02 (s, 3H),
1.11 (s, 3H), 1.62 (s, 3H), 1.70⎯1.90 (m, 5H), 1.94 (s, 3H), 2.20⎯30 (m, 2H), 2.28 (s, 3H), 2.49 (m, 1H),
2.90⎯3.05 (m, 2H), 3.82 (m, 1H), 4.03 (d, 1H, J = 7 Hz), 4.16 (d, 1H, J = 9 Hz), 4.28 (d, 1H, J = 9 Hz),
4.52 (dd, 1H, J = 11 Hz, 7 Hz), 4.82 (m, 1H), 4.96 (d, 1H, J = 9 Hz), 5.59 (d, 1H, J = 6 Hz), 7.32 (m, 1H),
7.46 (t, 2H, J = 8 Hz), 7.53 (d, 2H, J = 4 Hz), 7.59 (t, 1H, J = 8 Hz), 8.10 (m, 2H), 8.29 (d, 1H, J = 8 Hz);
MS (FAB) m/z: 886 (MH+).
10-Allyl-10-deacetoxy-7-O-triethylsilylbaccatin III (14)
To a stirred solution of 19 (886 mg, 1.0 mmol) in THF (26 mL) was added a THF (2 mL) solution of m-
chloroperbenzoic acid (181 mg, 1.05 mmol) at 0 °C. Stirring was continued for 3 h at ambient
temperature. After removal of the solvent under reduced pressure, the residue was chromatographed on
silica gel (CHCl3/n-hexane/acetone, 7:3:0.3) to give 14 (556 mg, 81%) as a colorless powder.
10-Deacetoxy-10-formylmethyl-7-O-13-O-bis-triethylsilylbaccatin III (20)
To a stirred solution of 14 (368 mg, 0.54 mmol) in DMF (5 mL) were added imidazole (367 mg, 5.4
mmol) and triethylsilyl chloride (0.90 mL, 5.4 mmol) at ambient temperature. After 2 h, the mixture was
poured into sat. NH4Cl, extracted with ethylacetate,washedwithbrine,driedoveranhydrousMgSO4, and
concentrated under reduced pressure. The residue was dissolved in THF/H2O (17 mL, 13:4, v/v), and N-
methylmorpholine N-oxide (168 mg, 1.44 mmol) and a catalytic amount of OsO4 were added . Stirring
was continued for 15 h at ambient temperature. The mixture was poured into brine, extracted with ethyl
acetate. The combined organic phase was dried over anhydrous MgSO4, and concentrated under reduced

pressure. The residue was dissolved in THF/MeOH/H2O (12 mL, 1:1:1, v/v/v), and NaIO4 (773 mg, 2.8
mmol) was added . After stirring for 6 h at ambient temperature, the mixture was diluted with H2O,
extracted with ethyl acetate. The combined organic phase was washed with brine, dried over anhydrous
MgSO4, and concentrated under reduced pressure. The residue was chromatographed on silica gel (n-
hexane/ethyl acetate, 9:1) to give 20 (173 mg, 79%) as a colorless amorphous solid; 1H-NMR (CDCl3) δ
0.55 (m, 6H), 0.62 (m, 6H), 0.92 (t, 9H, J = 8 Hz), 1.0 (t, 9H, J = 8 Hz), 1.08 (s, 3H), 1.11 (s, 3H), 1.62 (s,
3H), 1.89 (m, 1H), 1.96 (d, 3H, J = 1 Hz), 2.10 (m, 1H), 2.22 (m, 1H), 2.29 (s, 3H), 2.48⎯2.60 (m, 3H),
3.46 (dq, 1H, J = 17 Hz, 6 Hz, 2 Hz), 3.98 (d, 1H, J = 7 Hz), 4.15 (d, 1H, J = 9 Hz), 4.29 (d, 1H, J = 9
Hz), 4.44 (dd, 1H, J = 7 Hz, 5 Hz), 4.59 (dd, 1H, J = 11 Hz, 7 Hz), 4.86 (t, 1H, J = 8 Hz), 4.97 (d, 1H, J =
9 Hz), 5.60 (d, 1H, J = 7 Hz), 7.47 (t, 2H, J = 8 Hz), 7.60 (t, 1H, J = 8 Hz), 8.08 (m, 2H), 9.77 (t, 1H, J =
2 Hz); MS (FAB) m/z: 799 (MH+).
10-Deacetoxy-10-(2-hydroxyethyl)-7-O-13-O-bis-triethylsilylbaccatin III (21)
To a stirred solution of 20 (412 mg, 0.5 mmol) in MeOH (17 mL) was added NaBH4 (78 mg, 2.0 mmol) at
0 °C. Stirring was continued for 2 h at the same temperature. The mixture was diluted with CHCl3,
poured into ice-water, extracted with CHCl3. The combined organic phase was washed with brine, dried
over anhydrous MgSO4, and concentrated under reduced pressure. The residue was chromatographed on
silica gel (n-hexane/ethyl acetate, 4:1) to give 21 (398 mg, 96%) as a colorless amorphous solid; 1H-NMR
(CDCl3) δ 0.59 (m, 6H), 0.68 (m, 6H), 0.97 (t, 9H, J = 8 Hz), 1.01 (t, 9H, J = 8 Hz), 1.10 (s, 6H), 1.62 (s,
3H), 1.85 (m, 3H), 1.96 (s, 3H), 2.10 (m, 1H), 2.22 (m, 1H), 2.30 (s, 3H), 2.40⎯2.50 (m, 3H), 3.60 (br,
1H), 3.70 (br, 1H), 3.98 (m, 2H), 4.16 (d, 1H, J = 8 Hz), 4.30 (d, 1H, J = 9 Hz), 4.58 (dd, 1H, J = 7 Hz,
5 Hz), 4.91 (t, 1H, J = 8 Hz), 4.99 (d, 1H, J = 9 Hz), 5.60 (d, 1H, J = 7 Hz), 7.47 (t, 2H, J = 8 Hz), 7.60 (t,
1H, J = 8 Hz), 8.08 (d, 2H, J = 8 Hz); MS (FAB) m/z: 801 (MH+).
10-Deacetoxy-10-[2-(o-nitrophenylselenyl)ethyl]-7-O-13-O-bis-triethylsilylbaccatin III (22)
To a stirred solution of 21 (398 mg, 0.5 mmol) and o-nitrophenylselenocyanate (135 mg, 0.6 mmol) in
THF (8 mL) was added n-tributylphosphine (0.15 mL, 0.6 mmol) at 0 °C under N2 gas. Stirring was
continued for 2 h at ambient temperature. After removal of the solvent under reduced pressure, the
residue was chromatographed on silica gel (n-hexane/ethyl acetate, 4:1) to give 22 (450 mg, 92%) as a
colorless amorphous solid; 1H-NMR (CDCl3) δ 0.51 (m, 6H), 0.68 (m, 6H), 0.91 (m, 9H), 1.01 (m, 9H),
1.10 (s, 3H), 1.12 (s, 3H), 1.62 (s, 3H), 1.88 (m, 1H), 1.99 (s, 3H),2.10 (m, 2H), 2.23 (m, 1H), 2.29 (s,
3H), 2.50 (m, 1H), 2.61 (m, 1H), 2.83 (m, 1H), 2.94 (m, 1H), 3.92 (m, 2H), 4.15 (d, 1H, J = 8 Hz), 4.30 (d,
1H, J = 9 Hz), 4.59 (dd, 1H, J = 11 Hz, 7 Hz), 4.92 (m, 1H), 4.95 (d, 1H, J = 9 Hz), 5.60 (d, 1H, J = 7 Hz),
7.34 (t, 1H, J = 8 Hz), 7.47 (t, 2H, J = 8 Hz), 7.57 (m, 2H), 7.70 (d, 1H, J = 8 Hz), 8.09 (m, 2H), 8.31 (dd,
J = 8 Hz, 1 Hz, 1H); MS (FAB) m/z: 986 (MH+).

10-Deacetoxy-7-O-13-O-bis-triethylsilyl-10-vinylbaccatin III (23)
To a stirred solution of 22 (1.56 g, 1.58 mmol) in THF (45 mL) was added a THF (4 mL) solution of m-
chloroperbenzoic acid (70%, 468 mg, 1.9 mmol) at 0 °C. Stirring was continued for 2 h at ambient
temperature. After removal of the solvent under reduced pressure, the residue was chromatographed on
silica gel (n-hexane/ethyl acetate, 9:1) to give 23 (1.05 g, 85%) as a colorless amorphous solid; 1H-NMR
(CDCl3) δ 0.55 (m, 6H), 0.68 (m, 6H), 0.94 (m, 9H), 1.03 (m, 9H), 1.05 (s, 3H), 1.14 (s, 3H), 1.63 (s, 3H),
1.90 (m, 1H), 1.91 (d, 3H, J = 1 Hz), 2.11 (m, 1H), 2.25 (m, 1H), 2.30 (s, 3H), 2.46 (m, 1H), 4.02 (d, 1H,
J = 7 Hz), 4.17 (d, 1H, J = 9 Hz), 4.30 (d, 1H, J = 9 Hz), 4.48 (d, 1H, J = 3 Hz), 4.52 (dd, 1H, J = 11 Hz,
7 Hz), 4.96⎯5.06 (m, 3H), 5.23 (m, 1H), 5.60 (d, 1H, J = 7 Hz), 6.58 (m, 1H), 7.47 (t, 2H, J = 8 Hz),
7.59 (t, 1H, J = 8 Hz), 8.09 (m, 2H); MS (FAB) m/z: 783 (MH+).
10-Deacetoxy-10-formyl-7-O-13-O-bis-triethylsilylbaccatin III (24)
To a stirred solution of 23 (283 mg, 0.36 mmol) in THF-MeOH-H2O (1:1:1, v/v/v, 9 mL) were added N-
methylmorpholine N-oxide (213 mg, 2.0 mmol) and a catalytic amount of OsO4, and the reaction mixture
was stirred for 18 h.
mixture was extracted with ethyl acetate (30 mL x 3). The combined organic phase was washed with
brine, dried over anhydrous MgSO4, and concentrated under reduced pressure. The residue was
dissolved in THF-MeOH-H2O (1:1:1, v/v/v, 9 mL) and NaIO4 (387 mg, 1.8 mmol) was added , and stirred
for 13 h at ambient temperature. Saturated Na2S2O3 (50 mL) was added to the mixture and stirred for 1
The mixture was extracted with ethyl acetate (30 mL x 3). The combined organic phase was
Saturated Na2S2O3 (50 mL) was added to the mixture and stirred for 1 h.
The
h.
washed with brine, dried over MgSO4, and concentrated under reduced pressure.
After removal of the
solvent, the residue was chromatographed on silica gel (n-hexane/ethyl acetate, 9:1) to give 24 (272 mg,
96%) as a colorless solid; 1H-NMR (CDCl3) δ 0.59 (m, 6H), 0.68 (m, 6H), 0.97 (t, 9H, J = 8 Hz), 1.02 (s,
12H), 1.20 (s, 3H), 1.64 (s, 3H), 1.87 (s, 3H), 1.92 (m, 1H), 2.14 (m, 1H), 2.21 (m, 1H), 2.29 (s, 3H), 2.52
(m, 1H), 3.89 (d, 1H, J = 7 Hz), 4.15 (d, 1H, J = 8 Hz), 4.30 (d, 1H, J = 8 Hz), 4.58 (dd, 1H, J = 11, 7 Hz),
4.66 (s, 1H), 4.97 (m, 2H), 5.61 (d, 1H, J = 7 Hz), 7.47 (t, 2H, J = 8 Hz), 7.60 (t, 1H, J = 8 Hz), 8.09 (d,
2H, J = 8 Hz), 10.22 (s, 1H).; MS (FAB) m/z: 785 (MH+).
10-Deacetoxy-10-morpholinomethyl-7-O-13-O-bis-triethylsilylbaccatin III (25)
To a stirred solution of 24 (219 mg, 0.28 mmol) in EtOH (6 mL) were added morpholine (243 µL, 2.8
mmol) and acetic acid (160 µl, 1.28 mmol) at ambient temperature. The mixture was stirred for 5 min
at ambient temperature, then cooled to 0 oC.
mmol), and stirring was continued for 18 h at ambient temperature.
NaHCO3, extracted with CHCl3 (50 mL x 3). The combined organic phase was washed with brine and
dried over MgSO4. After removal of the solvent under reduced pressure, the residue was
chromatographed on silica gel (CHCl3/acetone, 95: 5) to give 25 (204 mg, 85%) as a pale yellow oil; 1H-
To the cooled solution was added NaBH3CN (175 mg, 2.8
The mixture was poured into sat.

NMR (CDCl3) δ 0.58 (m, 6H), 0.68 (m, 6H), 0.96 (t, 9H, J = 8 Hz), 1.01 (s, 12H), 1.09 (m, 3H), 1.17 (s,
3H), 1.60 (s, 3H), 1.88 (m, 1H), 2.00 (d, 3H, J = 1 Hz), 2.10 (m, 1H), 2.21 (m, 1H), 2.31 (s, 3H), 2.50 (m,
4H), 2.72 (dd, 1H, J = 14, 8 Hz), 3.10 (dd, 1H, J = 14, 4 Hz), 3.63 (m, 4H), 3.99 (d, 1H, J = 7 Hz), 4.07
(m, 1H), 4.15 (d, 1H, J = 8 Hz), 4.28 (d, 1H, J = 8 Hz), 4.55 (dd, 1H, J = 11, 6 Hz), 4.92 (m, 1H), 4.97 (m,
1H), 5.58 (d, 1H, J = 7 Hz), 7.47 (t, 2H, J = 8 Hz), 7.60 (t, 1H, J = 8 Hz), 8.08 (m, 2H); MS (FAB) m/z:
856 (MH+).
10-Deacetoxy-10-morpholinomethyl-7-O-triethylsilylbaccatin III (26)
To a stirred solution of 25 (18 mg, 0.02 mmol) in pyridine (1 mL) was added hydrogen fluoride pyridine
complex (0.2 mL, 0.14 mmol) at 0 °C. The mixture was stirred for 12 h at ambient temperature. The
mixture was diluted with ethyl acetate, washed with water and sat. NaHCO3, dried over anhydrous MgSO4,
and concentrated under reduced pressure. The residue was dissolved in DMF (1 mL), and imidazole (5.7
mg, 0.08 mmol) and triethylsilyl chloride (0.014 mL, 0.08 mmol) were added at 0 °C. The reaction was
stirred for 4 h at 0 °C. The mixture was poured into sat. NaHCO3 and extracted with CHCl3 (50 mL x 3).
The combined organic phase was washed with brine and dried over MgSO4.
After removal of the
solvent under reduced pressure, the residue was purified by TLC (5% MeOH/CHCl3) to give 26 (5 mg,
35%) as a pale yellow oil; 1H-NMR (CDCl3) δ 0.59 (m, 6H), 0.98 (t, 9H, J = 8 Hz), 1.10 (s, 6H), 1.62 (s,
3H), 1.60 (s, 3H), 1.89 (m, 1H), 2.06 (s, 3H), 2.29 (s, 3H), 2.50 (m, 5H), 2.72 (dd, 1H, J = 14, 8 Hz), 3.14
(dd, 1H, J = 14, 4 Hz), 3.64 (m, 4H), 4.08 (d, 1H, J = 7 Hz), 4.11 (dd, 1H, J = 8, 4 Hz), 4.15 (d, 1H, J = 8
Hz), 4.29 (d, 1H, J = 8 Hz), 4.57 (dd, 1H, J = 11, 6 Hz), 4.83 (m, 1H), 4.96 (d, 1H, J = 8 Hz), 5.58 (d, 1H,
J = 7 Hz), 7.47 (t, 2H, J = 8 Hz), 7.60 (t, 1H, J = 8 Hz), 8.10 (m, 2H); MS (FAB) m/z: 742 (MH+).
[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-2-O-tert-butyldimethylsilyl-3-phenylisoserinyl)-10-
deacetoxy-10-morpholinomethyl-7-O-triethylsilylbaccatin III (28)
To a stirred solution of 26 (5 mg, 6.4 µmol) and β-lactam (27) (4 mg, 9.6 µmol) in THF (1 mL) was added
NaHMDS (1.0 M in THF, 27 µL, 27 µmol) at -78 °C. The mixture was stirred for 15 min at the same
temperature. The mixture was poured into sat. NH4Cl, extracted with CHCl3 (50 mL x 3). The
combined organic phase was washed with brine and dried over MgSO4.
After removal of the solvent
under reduced pressure, the residue was purified by TLC (10% acetone/CHCl3) to give 28 (3.7 mg, 49%)
1
as a colorless oil; H-NMR (CDCl3) δ -0.32 (s, 3H), -0.12 (s, 3H), 0.58 (m, 6H), 0.75 (s, 9H), 0.95 (m,
9H), 1.12 (s, 3H), 1.28 (s, 3H), 1.31 (s, 9H), 1.62 (s, 3H), 1.85 (s, 3H), 1.90 (m, 1H), 2.11 (m, 1H), 2.40
(m, 1H), 2.50 (m, 6H), 2.52 (s, 3H), 2.62 (m, 1H), 3.20 (m, 1H), 3.64 (m, 4H), 4.00 (m, 2H), 4.19 (d, 1H,
J = 9 Hz), 4.30 (d, 1H, J = 9 Hz), 4.52 (m, 1H), 4.55 (m, 1H), 4.96 (d, 1H, J = 8 Hz), 5.31 (m, 1H), 5.44
(m, 1H), 5.65 (d, 1H, J = 7 Hz), 6.25 (m, 1H), 7.28⎯7.39 (m, 5H), 7.48 (t, 2H, J = 8 Hz), 7.57 (m,
1H),8.11 (d, 2H, J = 8 Hz); MS (FAB) m/z: 1119 (MH+).

[2'R,3'S]-13-O-(3-tert-Butoxycarbonylamino-3-phenylisoserinyl)-10-deacetoxy-10-
morpholinomethylbaccatin III (29)
To a stirred solution of 28 (3.7 mg, 3 µmol) in pyridine (1 mL) was added hydrogen fluoride pyridine
complex (0.2 mL) at 0 °C. The reaction was stirred for 12 h at ambient temperature. The mixture was
diluted with ethyl acetate and extracted with ethyl acetate. The combined organic phase was washed
with water and sat. NaHCO3, dried over anhydrous MgSO4 and concentrated under reduced pressure.
The residue was purified by TLC (8% MeOH/CHCl3) and freeze-dried from dioxane to give compound
1
(29) (2.9 mg, 100%) as a colorless powder; H-NMR (CDCl3) δ 1.09 (s, 3H), 1.22 (s, 3H), 1.31 (s, 9H),
1.65 (s, 3H), 1.82 (s, 3H), 1.89 (m, 1H), 2.21 (m, 1H), 2.29 (s, 3H), 2.30 (m, 1H), 2.58 (m, 4H), 2.61 (m,
1H), 3.42 (m, 1H), 3.61 (m, 4H), 3.92 (d, 1H, J = 7 Hz), 4.20 (d, 1H, J = 9 Hz), 4.29 (d, 1H, J = 9 Hz),
4.38 (dd, 1H, J = 11 Hz, 7 Hz), 4.60 (s, 1H), 4.95 (d, 1H, J = 8 Hz), 5.24 (m, 1H), 5.36 (m, 1H), 5.62 (d,
1H, J = 7 Hz), 5.19 (m, 1H), 7.30⎯7.39 (m, 5H), 7.50 (t, 2H, J = 8 Hz), 7.61 (t, 1H, J = 8 Hz), 8.11 (d,
2H, J = 8 Hz); MS (FAB) m/z: 891 (MH+); HR-MS Calcd for C48H63N2O14 : 891.4279. Found,891.4284.
REFERENCES AND NOTES
1. M. C. Wani, H. L. Taylor, M. E. Wall, P. Coggon, and A. Mcphail, J. Am. Chem. Soc., 1971, 93,
2325.
2. F. Gueritte-Voegelein, D. Guenard, F. Lavelle, M. -T. Le Goff, L. Mangatal, and P. Potier, J. Med.
Chem., 1991, 34, 992.
3. R. T. Dorr, Ann. Pharmacother., 1994, 28, S11; W. J. Slichenmyer and D. V. J. Hoff, Clin.
Pharmacol., 1990, 30, 770; W. C. Rose, F. Y. F. Lee, and A. M. Casazza, Cancer Chemother.
Pharmacol., 1997, 39, 486.
4. H. M. Deutsh, J. A. Glinski, M. Hernandez, R. D. Haugwitz, V. L. Narayanan, M. Suffness, and L. H.
Zalkow, J. Med. Chem., 1989, 32, 788; A. E. Mathew, M. R. Mejillano, J. P. Nath, R. H. Himes, and
V. J. Stella, J. Med. Chem., 1992, 35, 145; R. B. Greenwald, A. Pendri, and D. Bolikal, J. Org.
Chem., 1995, 60, 331; J. Golik, H. S. L. Wong, S. H. Chen, T. W. Doyle, J. J. K. Wright, J. Knipe,
W. C. Rose, A. M. Casazza, and D. M. Vyas, Bioorg. Med. Chem. Lett., 1996, 6, 1837; J. D.
Bourzat and A. Commercon, PCT Patent Appl., WO 9323389-A1 1993 [Chem. Abst., 1994, 120,
164575p]; E. W. P. Damen, P. H. G. Wiegerinck, L. Braamer, D. Sperling, D. D. Vos, and H. W.
Scheeren, Bioorg. Med. Chem., 2000, 8, 427.
5. K. Uoto, H. Takenoshita, T. Yoshino, Y. Hirota, S. Ando, I. Mitsui, H. Terasawa, and T. Soga, Chem.
Pharm. Bull., 1998, 46, 770.
6. K. Nakayama, H. Terasawa, I. Mitsui, S. Ohsuki, K. Uoto, S. Iimura, and T. Soga, Bioorg. Med. Chem.
Lett., 1998, 8, 427.
7. A. Commercon, D. Benzard, F. Bernard, and J. D. Bourzat, Tetrahedron Lett., 1992, 33, 5185; E.
Didier, E. Fouque, I. Taillepied, and A. Commercon, Tetrahedron Lett., 1994; 35, 2349.
8. I. Ojima, Acc. Chem. Res., 1995, 28, 383 and references cited therein.

9. R. F. Borch, M. D. Bernstein, and H. D. Durst, J. Am. Chem. Soc. , 1971, 93, 2897.
10. P. A. Grieco, S. Gilman, and M. Nishimura, J. Org. Chem., 1976, 41, 1485.
11. M Ishii., M. Iwahana, I. Mitsui, M. Minami, S. Imagawa, A. Tohgo, and A. Ejima, Anticancer Drugs,
2000, 11, 353.
®
12. PC-6/VCR29-9: PC-6 cell line which is resistant to Vincristine . SBC-3/ADM10: SBC-3 cell line
®
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which is resistant to Adriamycine . PC-6/VP1-1: PC-6 cell line which is resistant to Verapamil .