Synthesis and antitumor activity of goniofufurone analogues

Article abstract of DOI:10.1016/S0968-0896(99)00164-9

Synthesis and antitumor activity of goniofufurone analogues 15, 16, 17, 33, and 46 is reported. Key step in the synthesis is Pd (II) mediated oxidative cyclisation of vinyl-(hydroxy) furans 18, 19 to the corresponding lactols 32, 43. Cytotoxicities of 15,

Full text of DOI:10.1016/S0968-0896(99)00164-9

Bioorganic & Medicinal Chemistry 7 (1999) 2095±2103
Synthesis and Antitumor Activity of Goniofufurone Analogues
Hari Babu Mereyala, a,* Rajendrakumar Reddy Gadikota, a Maju Joe, a
Sudershan K. Arora, b Sunanda G. Dastidar b and Sudhanshu Agarwal b
aOrganic Chemistry Division III, Indian Institute of Chemical Technology, Hyderabad 500 007, India
bNew Drug Discovery Research, Ranbaxy Laboratories Limited, New Delhi 110 020, India
Received 12 April 1999; accepted 8 June 1999
AbstractÐSynthesis and antitumor activity of goniofufurone analogues 15, 16, 17, 33, and 46 is reported. Key step in the synthesis
is Pd (II) mediated oxidative cyclisation of vinyl-(hydroxy) furans 18, 19 to the corresponding lactols 32, 43. Cytotoxicities of 15,
16, 17, 33, and 46 tested against six human cancer cell lines are reported. Change of stereochemistry at C-5, C-6 and C-7 position of
goniofufurone (1) did not enhance the cytotoxicities signi®cantly. # 1999 Elsevier Science Ltd. All rights reserved.
Introduction
Results and Discussion
Synthesis
Bioactivity directed studies of the plant `goniothalamus
giganteus' Hook.F.,Thomas (Annonaceae) from Thailand
showed signi®cant murine toxicity in the 3 ps lymphocytic
leukaemia system.1±5 Several bioactive compounds have
been isolated and characterised, some representative
styryl lactones goniofufurone (1), 7-epigoniofufurone
(2), goniofupyrone (3), goniopypyrone (4), 9-deoxy-
goniopypyrone (5), goniotriol (6), goniobutenolides A
(7), B (8) and gonioheptolides A and B (9)5 are shown in
Figure 1. Among these 4 was the most bioactive showing
Herein, we report the synthesis of diastereomeric analo-
gues of goniofufurone (1) for evaluation as selective
antitumour agents. Synthesis of (5R,6S,7S)-diastereomer
(15), (5R,6R,7S)-diastereomer (16) of 1 and also one car-
bon higher analogue (17) was targetted for evaluating
them as antitumour agents. Retrosynthetic analyses of
15 and 16 (Scheme 1) indicated that the required [3.3.0]
bicyclic frame could be derived from intramolecular
Pd(II)Cl2 mediated oxidative cyclisation30 of the corre-
sponding vinyl (hydroxy) furans 18 and 19, respectively,
by the well documented protocol27,28 developed by us
earlier. 18 and 19 in turn could be derived from the dia-
cetone-d-mannose 20.29 17 By retrosynthesis (Scheme 1)
could be derived from 21 by Wittig ole®nation±cyclisa-
tion protocol. Synthesis of 21 itself is visualised from d-
glucose by established chemical reactions.31
1
non-selective ED50-values in cytotoxicity of 6.7Â10
mg/ml in the A-549 (human lung carcinoma), MCF-7
(human breast adeno-carcinoma), HT-29 (human colon
adenocarcinoma), high toxicity to the brine shrimp (BS)
and signi®cant inhibition of the formation of the crown
gall tumours on potato discs (PD). 1 Showed selective
but moderate toxic activity in A 549 and moderate toxi-
city to the brine shrimp.2 Absolute con®guration of 1 and
2 has been established by synthesis.6±23 Owing to their
potential as antitumour agents several diastereomers 10±
14 have been synthesised.24±28 As a part of our long term
programme in the fabrication of natural products as
potential antitumour agents, we recently described
stereoselective synthesis of (5-R)-diastereomer 14 of 1.27
Thus synthesis of 15 was achieved (Scheme 2) by reaction
of 20 with trimethylsulfoxonium iodide32(TMSOI) to
obtain an inseparable diastereomeric mixture of 22 and
23 (1:2.5 by H NMR).33
1
However, their corresponding benzyl ethers 24 and 25
were separated by column chromatography and hydro-
genated (Pd/C) to obtain 22 as a crystalline solid, mp
58±60ꢀC. Compound 22 was characterised from the H
1
NMR by the appearance of H-7 protons at d 3.45. 23 was
earlier characterised by 1H NMR and X-ray crystal-
lography.27 Swern oxidation of 22 gave the aldehyde
which on immediate reaction with phenylmagnesium bro-
mide at 20ꢀC in tetrahydrofuran gave a diastereomeric
Key words: Goniofufurone; diastereomers; antitumour; palladium (II)
chloride.
* Corresponding author. Tel.: +91-40-7170275; fax: +9-40-7173387;
e-mail: root@csiict.ren.nic.in
0968-0896/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
PII: S0968-0896(99)00164-9

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H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
Figure 1.
Scheme 1.
1
mixture of 26 and 27 (3:1 by H NMR) that were sepa-
rated by column chromatography. Characterisation of
26 and 27 was based on literature precedents on the 1,2-
addition of Grignard reagents to carbonyl com-
transformed to corresponding benzyl ether 28 and treated
with 60% aqueous acetic acid at room temperature to
obtain the diol 29. Reaction of 29 with methanesulfonyl
chloride/triethylamine gave dimesylate 30 which on fur-
ther reaction with NaI/butan-2-one gave the desired
ole®n 3137 in 82% yield. Formation of 31 was evident
pounds8,11,34±36 and H NMR spectra. 1,2-Addition of
1
alkylmagnesium halide to analogous aldehydes has been
reported and to result in the formation of `threo' isomer
as a major product due to approach of nucleophile from
the plane opposite to the furanose ring. Thus 26 was
assigned the `threo' and 27 `erythro' con®guration
respectively. 1H NMR spectrum of 26 was also in
agreement with the assigned structure. Compound 26 was
1
from the H NMR spectrum from the appearance of
ole®nic protons at d 5.2 (1H), 5.3 (1H), 5.8±6.0 (1H) and
isopropylidene methyl protons at d 1.4, 1.48 (6H). Reac-
tion of 31 in dioxane containing 5% aqueous H2SO4 at
re¯ux temperature for 1.5 h gave the diol 18. Intramo-
lecular oxidative cyclisation of 18 was achieved by

H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
2097
Scheme 2. Reagents and conditions: (a) TMSOI, NaH, DMSO, 0ꢀC-r.t, 1 h, (b) BnBr, NaH, DMF,0ꢀC, 30 min., (c) Pd/C, MeOH, H2, r.t, 3 h, (d)
Oxalyl chloride, DMSO,TEA, CH2Cl2, 78ꢀC, 1 h ; PhMgBr, THF, 20ꢀC, 4 h, (e) BnBr, NaH, DMF,0ꢀC, 30 min, (f) 60% aq.acetic acid, r.t, 12 h,
(g) MsCl, TEA, CH2Cl2, 0ꢀC-r.t, 1 h, (h) NaI, 2-butanone, re¯ux,12 h, (i) 5% aq.H2SO4, dioxane, re¯ux, 1.5 h, (j) PdCl2, CuCl, DMF:H2O (4:1), O2,
r.t, 3 h, (k) PDC, CH2Cl2, re¯ux, 1.5 h, (l) 10% Pd/C, MeOH, H2, r.t, 2 h.
reaction with PdCl2-CuCl in DMF: water (4:1) while
oxygen was bubbled to obtain the lactol 32 in 83% yield.
Formation of 32 was evident from the disappearance of
ole®nic protons between d 5.2±6.0 (3H) and appearance
of acetal proton H-1 at d 5.2±5.5 (1H) and methylene
protons between d 1.9±2.2 (2H). Oxidation of 32 with
PDC in dichloromethane at re¯ux temperature for 1.5 h
gave lactone 33 as a crystalline solid, mp 77±80ꢀC in
78% yield. Compound 33 was characterised from the
of H-7 at d 5.9. Inversion of con®guration at C-7 of 36
was evident because H-7 proton of (7S)-p-nitrobenzoyl
derivative 37 appeared relatively down®eld at d 6.1 in
1
the H NMR spectrum. Compound 37 was prepared
from 35 by reaction with p-nitrobenzoic acid/DCC/r.t.
36 reacted with methanol containing a catalytic amount
of sodium methoxide to obtain the alcohol 38 and on
further reaction with benzyl bromide/NaH gave the
benzyl ether 39. Acid catalysed deprotection of 39 in
60% aq.HOAc at room temperature for 1 h gave the
diol 40 which was further treated with methanesulpho-
nyl chloride to obtain the dimesylate 41. Compound 41
reacted with sodium iodide in butan-2-one to obtain
vinylfuran 42 and on acid catalysed hydrolysis in 5%
aq. H2SO4 in dioxane gave the vinyl (hydroxy) furan 19 as
a crystalline solid, mp 108±110ꢀC in high yield. Pd(II)Cl2
mediated oxidative cyclisation of 19 was a€ected as a
key step to obtain the lactol 43. Oxidation of 43 with
PDC in CH2Cl2 gave the lactone 44 as a crystalline
solid, mp 102±104ꢀC. Hydrogenolysis of 44 (10% Pd-
BaSO4) in ethyl acetate gave the required (5R,7S)-dia-
stereomer 16 as a crystalline solid, mp 118±120ꢀC and
appearance of carbonyl absorption in the IR at 1782
1
cm
for the furanolactone and appearance of H-2
protons at d 2.6±2.8 (2H). Compound 33 on hydro-
genolysis in methanol gave the desired tetrahydro-
furofurone 15 in 51% yield along with the deoxygenated
1
product 34 (13%). 15 was characterised by H NMR
spectrum from the appearance of H-2,20 at d 2.7, H-4
and H-7 protons between d 4.88±4.93 and characteristic
1
lactone absorption at 1784 cm in the IR spectrum.
Compound 34 was characterised from the 1H NMR
spectrum from the appearance of benzylic protons at d
2.8±3.1.
1
Next, we planned to achieve the synthesis of 16 from 35
by inverting the con®guration at C-7 hydroxyl group
(Scheme 3) under Mitsunobu reaction conditions.
Reaction of 3527 with DEAD/triphenylphosphine/p-
nitrobenzoic acid gave (7R)-diastereomer 36 as a white
crystalline solid, mp 131±133ꢀC in 83% yield and was
characterised by 1H NMR spectrum from the appearance
was characterised from the H NMR and IR spectra.
It was planned to obtain (5S,7S)-diastereomers 44a and
45a, respectively, from the corresponding (5R,7S)-(44),
(5R, 7R)-diastereomers (45).27 This transformation we
planned to achieve by use of Mitsunobu reaction con-
ditions. Reaction of 44 and 45 severally with diethyl

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H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
azodicarboxylate (DEAD)-triphenylphosphine-p-nitro-
benzoic acid, however, met with failure; it resulted in
the recovery of starting material.
Cytotoxicities
The cytotoxicities of 15, 16, 17, 33 and 46 were tested in
vitro by measuring the inhibition of cell growth. As
shown in Table 1, goniofufurone analogues generally
exhibited weak inhibition in six cell lines.
Synthesis of 17 was planned involving Wittig ole®na-
tion±cyclisation of advanced intermediate 21 (Scheme 1)
as a key step to realise the tetrahydrofuranolactone
(Scheme 4). Thus, 21 was prepared from diacetone-d-
glucose in seven steps by reported procedures.31 21
reacted with Ph3PˆCHCOOEt in MeOH at 0ꢀC for 4 h
to obtain the lactone 46 and was characterised from the
appearance of H-2 and H-4 protons between d 2.5±3.2
Conclusion
In conclusion we have described ecient synthesis of
goniofufurone analogues 15 and 33 by Pd(II)Cl2 medi-
ated oxidative cyclisation of vinyl (hydroxy) furans as a
key step and 17 by Wittig ole®nation-cyclisation of 21.
We found that change of stereochemistry at C-5, C-6
and C-7 position of goniofufurone (1) did not enhance
the cytotoxicities signi®cantly.
1
(4H) in the H NMR spectrum and lactone absorption
1
at 1780 cm in the IR spectrum. Compound 46 was
hydrogenated (Pd/C/MeOH/ 1 atm) to obtain the
required lactone 17 and was characterised from 1H
NMR and IR spectra.
Scheme 3. Reagents and conditions: (a) DEAD, TPP, Pnb-acid, THF, 0ꢀC, r.t., 6 h, (b) DCC, CH2Cl2, Pnb-acid, r.t, 8 h (c) NaOMe, MeOH, r.t, 1
h, (d) BnBr, NaH, DMF, 0ꢀC, 45 min, (e) 60% aq.acetic acid r.t, 9 h, (f) MsCl, TEA, CH2Cl2, 0ꢀC, r.t, 30 min, (g) NaI, 2-butanone, re¯ux, 12 h, (h)
5% aq.H2SO4, dioxane, re¯ux, 1 h, (i) PdCl2, CuCl, DMF:H2O (4:1), O2, r.t, 5 h, (j) PDC, CH2Cl2, re¯ux, 1.5 h, (k) 10% Pd/C, EtOAc, H2, r.t, 1 h.
Scheme 4. Reagents and conditions: (a) Ph3P=CHCOOEt, MeOH, 0ꢀC, 4 h, (b) 10% Pd/C, MeOH, H2, r.t, 3 h.
Table 1. Bioactivities of 15, 16, 17, 33 and 46 (GI50 values mM)
Tumor type
Cell line
15
16
17
33
46
Adriamycin
Prostate
Colon
Melanoma
Breast
Breast resistant
CNS
DU 145
HT 29
LOX
MCF
MCF-7/ADR
U251
57.95
5.68
4.1
128.07
269.36
217.35
254.35
134.33
147.83
144.62
147.28
130.9
72.24
82.53
189.69
91.93
9.21
5.51
93.14
19.79
66.8
82.64
64.99
29.36
64.91
27.04
89.34
0.19
0.33
0.03
0.15
0.12
0.02
75.74
>200
60.17

H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
2099
Experimental
chloride (2.29g, 18.2 mmol) in dichloromethane (10 ml)
at 78ꢀC and the resulting solution was stirred for 15
min. A solution of 22 (2.5 g, 9.1 mmol) in dry dichloro-
methane (15 ml) was added to the above reaction mixture
and stirred for 1 h and triethylamine (3.67 g, 36.4 mmol)
was added. The reaction mixture was brought gradually
to room temperature and diluted with CH2Cl2 (100
mL). Organic phase was separated, washed with satd.
sodium chloride solution water, dried (Na2SO4), ®ltered
and evaporated to obtain the aldehyde, which without
further puri®cation was immediately treated with 1 M
solution of phenylmagnesium bromide (18 ml, 18.2
mmol) in dry THF (20 mL) under nitrogen atmosphere
for 4 h at 0ꢀC. After completion of the reaction it was
quenched with satd. aqueous ammonium chloride solu-
tion (25 mL) and ®ltered. The ®ltrate was concentrated
to a syrupy residue and extracted into diethyl ether
(2Â100 mL). The combined organic extracts were
washed with water, dried (Na2SO4), ®ltered and con-
centrated to obtain a residue which was separated by
column chromatography (SiO2, 60±120 mesh; hexane:
EtOAc 4.5:1) to elute ®rst 27 (0.63 g, 20%) as a syrup.
Chemistry
1H NMR spectra were measured with a Varian Gemini
200 MHz spectrometer with tetramethylsilane as inter-
nal standard for solutions in deuteriochloroform. J
values are given in Hz. 13C NMR spectra were taken
with a Varian Gemini (50, 100 MHz) with CDCl3 as
internal standard (dc 77.0) for solutions in deuterio-
chloroform. Optical rotations were measured with a
JASCO DIP-370 instrument and [a]d- values are in units of
1
10 deg/cm g. All melting points are uncorrected. IR
spectra were recorded on a Perkin±Elmer 1310 spectro-
meter. All organic solvents were freshly distilled prior to
use. Air sensitive reactions were generally performed under
a positive pressure of nitrogen within glassware, which had
been ¯ame-dried under a stream of dry nitrogen.
3,6-Anhydro-7-O-benzyl-1,2:4,5-di-O-isopropylidene-D-
glycero-D -galacto-heptitol (24) and 3,6-anhydro-7-O-
benzyl-1,2:4,5-di-O-isopropylidene-D-glycero-D-manno-hep-
titol (25). To a slurry of hexane washed sodium hydride
(1.5 g, 62.9 mmol) in dry N,N-dimethylformamide
(DMF) (10 ml) diastereomeric mixture of 22, 23 (11.5 g,
41.9 mmol) in dry DMF (10 ml) was added at 0ꢀC. To
this suspension, benzyl bromide (9.27 g, 54.6 mmol) was
added dropwise and stirred for 30 min. After comple-
tion of the reaction methanol (1 mL) was added and the
reaction mixture was poured into ice cold water and
extracted into diethyl ether (2Â200 mL). Combined
ethereal extracts were dried (Na2SO4) and concentrated
in vacuo to give a mixture of 24, 25 that was separated
by column chromatography (SiO2, 60-120 mesh; hexane:
EtOAc 4:1) to elute ®rst 24 (4.02 g, 26%) as a syrup.
[a]d 8.8 (c 1.0, CHCl3).1H NMR (CDCl3); d 1.30, 1.32,
1.42, 1.48 (12H, 4s, 4ÂCH3), 3.52 (2H, d, J 4.5, H-7),
4.45±4.82 (9H, m, H-1,10,2-6 and CH2Ph), 7.18±7.42
(5H, m, ArH). Anal. calcd for C20H28O6: C, 65.91; H,
7.74. Found: C, 65.72; H, 67.66 and elute next 25 (9.8 g,
1
[a]d 1.3 (c 1.5, CHCl3): H NMR (CDCl3); d 1.32, 1.40,
1.45, 1.55 (12H, 4s, 4ÂCH3), 2.75 (1H, br.s, OH), 3.45±
3.58 (2H, m, H-1,10), 3.98±4.8 (5H, m, H-2-6), 5.05 (1H,
d, J 6.75, H-7), 7.15±7.4 (5H, m, ArH ). Anal. calcd for
C19H26O6: C, 65.12; H, 7.48. Found: C, 65.02; H, 7.39,
followed by 26 (1.85 g, 58%) as a white solid; mp 124±
126ꢀC. [a]d 9.0 (c 1.0, CHCl3). H NMR (CDCl3); d
1
1.28, 1.52 (12H, 4s, 4ÂCH3), 3.35±4.05 (4H, m, H-
1,10,3,6), 4.32 (1H, ddd, J 7.15, 7.02, 7.24, H-2), 4.6±
4.75 (2H, m, H-4,5), 4.87 (1H, t, J 4.2, H-7), 7.1±7.4
(5H, m, ArH). Anal. calcd for C19H26O6: C, 65.12; H,
7.48. Found: C, 65.01; H, 7.41.
(7S)-3,6-Anhydro-7-O-benzyl-1,2:4,5-di-O-isopropylidene-
7-C-phenyl-D-glycero-D-galacto-heptitol (28). To a slurry
of hexane washed sodium hydride (0.24 g, 10.2 mmol) in
DMF (5 ml) was added compound 26 (1.8 g, 5.14 mmol)
in DMF (5 mL) at 0ꢀC. To this suspension was added
benzyl bromide (1.3 g, 7.65 mmol) and the reaction
mixture stirred for 30 min at room temperature. After
completion of the reaction it was poured into ice cold
water and extracted into diethyl ether (2Â75 mL). The
combined ethereal layers were washed with water, dried
(Na2SO4), ®ltered and concentrated in vacuo to obtain
the title compound 28 (2.05 g, 90%) as a syrup. [a]d 18.0
1
64%) as a syrup. [a]d 54.3 (c 1.3, CHCl3). H NMR
(CDCl3); d 1.35, 1.38, 1.44, 1.48 (12H, 4s, 4ÂCH3), 3.4±
4.1 (6H, m, H-1,10,2,6,7,70), 4.4±4.8 (5H, m, H-3-5, and
CH2Ph), 7.18±7.40 (5H, m, ArH). Anal. calcd for
C20H28O6: C, 65.91; H, 7.74. Found: C, 65.83; H, 7.68.
3,6-Anhydro-1,2:4,5-di-O-isopropylidene-D-glycero-D-
gal-acto-heptitol (22). A solution of compound 24 (3.95 g,
10 mmol) in MeOH (30 ml) containing 10% Pd-BaSO4
(0.1 g) was stirred under hydrogen atmosphere for 4 h.
After completion of the reaction the catalyst was ®ltered
o€ and the solvent removed to obtain the title compound
22 (2.85 g. 95%) as a white crystalline solid, mp 58±60ꢀC.
1
(c 1.0 CHCl3). H NMR (CDCl3); d 1.29, 1.31, 1.38,
1.49 (12H, 4s, 4ÂCH3), 3.35±3.98 (4H, m, H-1,10,3, 6),
4.1±4.55 (3H, m, H-2 and CH2Ph), 4.6 (1H, d, J 6.6, H-
7), 4.75 (1H, dd, J 5.8,3.4, H-4), 4.9 (1H, dd, J 3.6, 5.8,
H-5), 7.15±7.45 (10H, m, ArH). Anal. calcd for
C26H32O6: C, 70.89; H, 7.32. Found: C, 70.82; H, 7.29.
1
[a]d 9.0 (c 2.6, CHCl3). H NMR (CDCl3); d 1.3, 1.32,
1.41, 1.48 (12H, 4s, 4ÂCH3), 2.2 (1H, br.s, OH ), 3.41±
4.15 (6H, m, H-1,10,3,6,7,70), 4.32 (1H, ddd, J 7.01, 7.21,
7.29, H-2), 4.6±4.78 (2H, m, H-4 and 5), Anal. calcd for
C13H22O6: C,56.84; H,7.95. Found: C, 56.77; H, 7.89.
(7S)-3,6-Anhydro-7-O-benzyl-4,5-O-isopropylidene-7-C-
phenyl-D-glycero-D-galacto-heptitol (29). A solution of
compound 28 (2 g, 4.5 mmol) in 60% aq. acetic acid (20
mL) was stirred at room temperature for 8 h and pro-
gress of the reaction was monitored by t.l.c. After com-
pletion of the reaction solvents were removed in vacuo
to obtain a residue which was ®ltered on a bed of silica
gel (hexane:EtOAc 1:1) to obtain the title compound 29
(1.54 g, 85%) as a thick syrup. [a]d 27.0 (c 2.0, CHCl3).
7S)-3,6-Anhydro-1,2:4,5-di-O-isopropylidene-7-C-phenyl-
D-glycero-D-galacto-heptitol (26) and (7R)-3,6-anhydro-
1,2:4,5-di-O-isopropylidene-7-C-phenyl-D-glycero-D-gal-
acto- heptitol (27). Dimethyl sulphoxide (2.26 g, 20.9
mmol) was added to a stirred solution of the oxalyl

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H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
1H NMR (CDCl3); d 1.35, 1.5 (6H, 2s, 2ÂCH3), 2.5
(1H, br.s, OH), 3.35±4.17 (5H, m, H-1,10,2,3,6), 4.3±4.5
(2H, 2d, J 11.8, CH2Ph), 4.62 (1H, d, J 6.5, H-7), 4.75±
4.94 (2H, m, H-4,5), 7.17±7.48 (10H, m, ArH). Anal.
calcd for C23H28O6: C, 69.98; H, 7.05. Found: C, 69.89;
H, 7.01.
(1H, m, H-2), 7.17±7.52(10H, m, ArH). Anal. calcd for
C20H22O4: C, 73.60, H, 6.79%. Found: C, 73.55, H,
6.73.
(7S)-3,6-Anhydro-7-O-benzyl-2-deoxy-7-C-phenyl-D-allo-
1,4-heptanolactol (32). To a solution of 18 (0.62 g, 1.9
mmol) in DMF-water (4:1, 5 ml) was added palladium
(II) chloride (0.067 g, 0.37 mmol), copper (I) chloride
(0.19 g, 1.9 mmol) and oxygen was bubbled for 3 h at
room temperature. After completion of the reaction 2%
aqueous HCl was added to the reaction mixture and
extracted into diethyl ether (2Â75 ml). Combined ethereal
solution was washed with water, dried (Na2SO4), ®ltered
and concentrated to obtain the title compound 32 (0.54
(7S)-3,6-Anhydro-7-O-benzyl-4,5-O-isopropylidene-1,2-bis-
O-(methylsulfonyl)-7-C-phenyl-D-glycero-D-galacto-hep-
titol (30). To a stirred solution of diol 29 (1.2 g, 3
mmol) and triethylamine (1.51 g, 15 mmol) in dichloro-
methane (25 mL) was added methanesulfonyl chloride
(1.02 g, 9 mmol) at 0ꢀC and gradually brought to room
temperature. The reaction mixture was diluted with
water and organic phase was separated. The aqueous
phase was extracted with CH2Cl2 (2Â50 mL) and the
combined organic layers were washed with satd.
NaHCO3 solution (50 mL), water, dried (Na2SO4), ®l-
tered and concentrated to obtain a residue. Puri®cation
of the crude residue by column chromatography on silica
gel (hexane:EtOAc 2:1) gave the title compound 30 (1.42
1
g, 83%) as a syrup. H NMR (CDCl3); d 1.9±2.2 (2H,
m, H-2,20), 2.9 (1H, br.s, OH), 3.4±4.88 (7H, m, H-3-7
and CH2Ph), 5.5±5.75 (1H m, a/b), 7.19±7.52 (10H, m,
ArH). Anal. calcd for C20H22O5: C, 70.16; H, 6.48%.
Found: C, 70.12; H, 6.39.
(7S)-3,6-Anhydro-7-O-benzyl-2-deoxy-7-C-phenyl-D-allo-
1,4-heptanolactone (33). To a solution of the lactol 32
(0.5 g, 1.46 mmol) in dry CH2Cl2 (10 ml) containing
powdered 4Aꢀmolecular sieves (20 mg) was added pyr-
idinium dichromate (0.65 g, 1.72 mmol) and re¯uxed for
1.5 h. When the reaction was complete, diethyl ether
was added, reaction mixture was ®ltered through a bed
of silica gel and eluted with diethyl ether. The ethereal
solution was concentrated to obtain a brown residue
which was puri®ed on a bed of silica gel (hexane: EtOAc
1:1) to yield the title compound 33 (0.39 g, 78%) as a
white crystalline solid. Mp 77±80ꢀC. [a]d 14.0 (c 0.7,
1
g, 85%) as a syrup. [a]d 27.0 (c 2.0, CHCl3). H NMR
(CDCl3); d 1.38, 1.49 (6H, 2s, 2ÂCH3), 3.05, 3.08 (6H,
2s, 2ÂSCH3), 3.6±4.15 (5H, m, H-1,10,2,3,6), 4.39±4.50
(2H, 2d, J 12.0, CH2Ph), 4.58 (1H, d, J 6.3, H-7), 4.75±
4.98 (2H, m, H-4,5), 7.18±7.50 (10H, m, ArH). Anal. calcd
for C25H32O10 S2 : C, 53.93; H, 5.79. Found: C, 53.87;
H, 5.72.
(7S)-3,6-Anhydro-7-O-benzyl-1,2-dideoxy-4,5-O-isopropyl-
idene-7-C-phenyl-D-altro-hept-1-enitol (31). To a solution
of 30 (1.4 g, 2.5 mmol) in butan-2-one (50 mL) was
added sodium iodide (1.51 g, 12.2 mmol) and re¯uxed
for 12 h. When the reaction was complete, solvent was
removed in vacuo; a solution of satd. aqueous sodium
thiosulphate was added and extracted into diethyl ether
(2Â75 ml). Combined organic layers were washed with
water, dried (Na2SO4) and concentrated under reduced
pressure to obtain a syrupy residue which was ®ltered
on a bed of silicagel (hexane:EtOAc 4:1) to obtain the
title compound 31 (0.76 g, 82%) as a colourless syrup.
1
CHCl3). IR nmax (KBr). 1782 cm 1. H NMR (CDCl3);
d 2.65 (2H, d, J 4.6, H-2,20), 2.9 (1H, br.s, OH), 3.9 (1H,
dd, J 6.3, 4.5, H-6), 4.05±4.6 (m, 4H, H-3,5 and
CH2Ph), 4.7 (1H, d, J 6.3, H-7), 4.95 (1H, t, J 4.3, H-4),
7.15±7.52 (10H, m, ArH). 13C NMR (CDCl3, 100MHz)
d 36.8 (C-2), 70.8 (C-5), 73.8 (C-3), 76.6 (C-6), 81.8 (C-
4), 82.9 (OCH2Ph), 85.0 (C-7), 127.5±137.4 (Aromatic),
175.1 (CˆO). Anal. calcd for C20H20O5 : C, 70.57; H,
5.92%. Found C, 70.51; H, 5.86.
1
[a]d 1.6 (c 1.4, CHCl3), H NMR (CDCl3); d 1.40, 1.48
(6H, 2s, 2ÂCH3), 3.6 (1H, dd, J 6.7, 6.3, H-6), 3.88 (1H,
m, H-4), 4.3±4.5 (2H, 2d, J 11.9, CH2Ph), 4.65 (2H, m,
H-3,7), 4.92 (1H, dd, J 3.95, 4.2, H-3), 5.2 (1H, dd, J
10.2, 1.9, H-1), 5.25 (1H, dd, J 16.3, 1.5, H-10), 5.78±6.0
(1H, m, H-2), 7.18±7.52 (10H, m, ArH). Anal. calcd for
C23H26O4: C, 75.38; H, 7.15%. Found: C, 75.33; H,
7.11.
3,6-Anhydro-2,7-dideoxy-7-C-phenyl-D-allo-1,4-heptanol-
actone 34 and (7S)- 3,6-Anhydro-2-deoxy-7-C-phenyl-D-
allo-1,4-heptanolactone (15). Compound 33 (0.3 g, 0.88
mmol) was dissolved in methanol (5 ml), 10% Pd/C (10
mg) was added and the reaction mixture was stirred
under hydrogen atmosphere (1 atm) for 3 h. The cata-
lyst was ®ltered o€ and the solvent removed in vacuo to
obtain a mixture of 34 and 15 that were separated by
column chromatography (SiO2, 60±120 mesh, hexane:
EtOAc 1:1). Eluted ®rst was 34 (0.026 g, 13%) as a
crystalline solid, mp 109±111ꢀC. [a]D. 11.0 (c 1.0,
CHCl3). IR nmax (KBr).1782 cm 1. 1H NMR (CDCl3); d
2.2 (1H, br.s, OH), 2.6±3.2 (4H, m, H-2,20,7,7), 3.88±4.6
(3H, m, H-3,5,6), 4.92 (1H, d, J 6.7, H-4), 7.1±7.4 (5H,
m, ArH). Anal. calcd for C13H14O4: C,66.66 ; H,6.02%.
Found.: C,66.62; H, 5.98. Eluted next was compound 15
(0.112 g, 51.0%) as a white crystalline solid, mp 52±
54ꢀC. [a]d 82.0 (c 0.95, CHCl3). IR nmax (KBr) 1784
(7S)- 3,6-Anhydro-7-O-benzyl-1,2-dideoxy-7-C-phenyl-D-
allo-hept-1-enitol (18). To a solution of 31 (0.9 g, 2.4
mmol) in 1,4-dioxane (10 ml) was added 5% aq sulphuric
acid (0.5 ml) and re¯uxed for 1 h. After completion of the
reaction, solvent was removed in vacuo to obtain a residue
which was extracted into ethyl acetate. Combined
organic layers were washed with satd. NaHCO3 solution,
water, dried (Na2SO4), ®ltered and concentrated to
obtain the diol 18 (0.66 g, 82%) as a syrup. [a]d 7.0 (c,
1
0.5, CHCl3). H NMR (CDCl3); d 2.8 (1H, br.s, OH),
1
3.95 (1H, dd, J 6.75, 6.3, H-6), 4.1±4.6 (5H, m, H-3-5
and CH2Ph), 4.78 (1H, d, J 4.2, H-7), 5.21 (1H, dd, J
9.9, 1.3, H-1), 5.30 (1H, dd, J 16.5, 1.9, H-1'), 5.85±6.03
cm 1. H NMR (CDCl3); d 2.7 (2H, m, H-2,2), 3.9±4.2
(3H, m, H-3,5,6), 4.88±4.93 (2H, m, H-4,7), 7.14±7.50
(5H, m, ArH). 13C NMR (CDCl3, 50MHz) d 36.8 (C-2),

H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
2101
71.1 (C-5), 73.8 (C-3), 82.1 (C-6), 83.08 (C-4), 85.3 (C-
7), 127.7±137.7 (Aromatic), 175.1 (CˆO). Anal. calcd
for C13H14O5: C, 62.39; H, 5.64%. Found: C, 62.31; H,
5.59.
temperature, poured into ice cold water and extracted
into diethyl ether (2Â60 mL). The combined ethereal
extracts were washed with water, dried over Na2SO4,
®ltered and concentrated in vacuo to yield the title
compound 39 (3 g, 96%) as a syrup. [a]d 23.0 (c 1.0,
1
(7S)-3,6-Anhydro-1,2:4,5-di-O-isopropylidene-7-C-phenyl-
7-O-(4-nitro-benzoyl)-D-glycero-D-manno-heptitol (36).
To a solution of alcohol 35 (3.8 g, 10.8 mmol) in dry
THF (75 ml) was added 4-nitrobenzoic acid (5.4 g, 32.3
mmol), triphenylphosphine (10.4 g, 39.6 mmol), diethyl-
azadicarboxylate (7.5 g, 43.1 mmol) at 0ꢀC and the
reaction mixture was stirred for 8 h. After completion of
the reaction solvent was removed in vacuo to obtain a
residue which was puri®ed by column chromatography
(SiO2,60±120 mesh, hexane:EtOAc 4:1) to obtain the
title compound 36 (4.5 g, 83%) as a crystalline solid, mp
131±133ꢀC. [a]d 36.0 (c 0.9, CHCl3). 1H NMR (CDCl3);
d 1.35, 1.48,1.55 (12H 4s, 4ÂCH3), 3.7±4.05 (3H, m, H-
1,10,2), 4.2±4.35 (1H, m, H-2), 4.40 (1H, d, J 6.95, H-6),
4.75±4.90 (2H, m, H-4,5), 5.98 (1H, d, J 6.95, H-7), 7.3±
7.5 (5H, m, ArH), 8.18±8.4 (4H, m, ArH). Anal. calcd
for C26H29NO9. : C, 62.51, H, 5.85, N, 2.86%. Found:
C, 62.46, H, 5.75, N, 2.78.
CHCl3). H NMR (CDCl3); d 1.3, 1.39, 1.45 (12H, 4s,
4ÂCH3), 3.85±4.48 (7H, m, H-1, 10, 2, 3, 6 and CH2Ph),
4.57 (1H, dd, J 4.1, 3.92, H-5), 4.78 (1H, dt, J 3.9, H-4),
4.98 (1H, d, J 6.9, H-7), 7.1±7.45 (10H, m, ArH). Anal.
calcd for C26H32O6: C, 70.89; H, 7.32%. Found: C,
70.83; H, 7.28.
(7S)-3,6-Anhydro-7-O-benzyl-1,2-O-isopropylidene-7-C-
phenyl-D-glycero-D-manno-heptitol (40). A solution of
compound 39 (2.95 g, 6.7 mmol) in 60% aq. acetic acid
(25 ml) was stirred at room temperature for 8 h. Pro-
gress of the reaction was monitored by TLC and when
complete solvents were removed under high vacuum to
obtain a residue which was ®ltered on a bed of silica gel
(hexane:EtOAc 1:1) to yield the title compound 40
(2.3 g, 86%) as a thick syrup. [a]d 29.0 (c 1.6, CHCl3).
1H NMR (CDCl3); d 1.25,1.4 (6H, 2s, 2xCH3), 1.95
(1H, br.s, OH), 3.5±4.12 (5H, m, H-1,10,2,3,6), 4.23 (1H,
d, J 11.3, CH2Ph), 4.4±4.55 (2H, m, H-5 and CH2Ph),
4.74 (1H, dd, J 3.8, 4.4, H-4), 4.9 (1H, d, J 6.7, H-7),
7.15±7.4 (10H, m, ArH). Anal. calcd for C23H28O6: C,
69.98; H, 7.05%. Found: C, 69.88; H, 6.99.
(7R)-3,6-Anhydro-1,2:4,5-di-O-isopropylidene-7-C-phenyl-
7-O-(4-nitrobenzoyl)-D-glycero-D-manno-heptitol (37).
To a solution of alcohol 35 (0.5 g, 1.42 mmol) in
CH2Cl2 (25 ml) was added DCC (0.58 g, 2.8 mmol) and
4-nitrobenzoic acid (0.35 g, 2.1 mmol) and stirred for 7 h.
After completion of the reaction dicyclohexylurea was
removed by repeated crystallisation with hexane: EtOAc
and the crude was ®ltered on a bed of silica gel (hexane:
EtOAc 4:1) to obtain the title compound 37 (0.56 g,
78%) as a crystalline solid. Mp 141±142ꢀC. [a]d 28.0 (c
(7S)-3,6-Anhydro-7-O-benzyl-4,5-O-isopropylidene-1,2-bis-
O-(methylsulfonyl)-7-C-phenyl-D-glycero-D-manno-heptitol
(41). To a stirred solution of diol 40 (2.2 g, 5.5 mmol)
and triethylamine (2.22 g, 22 mmol) in dichloromethane
(50 mL) was added methanesulfonyl chloride (1.8 g, 16.5
mmol) at 0ꢀC and brought to room temperature. After
completion of the reaction it was diluted with water and
the organic phase was separated. The aqueous phase was
extracted with CH2Cl2 (2Â50 mL) and the combined
organic layers were washed with satd. NaHCO3 solution
(50 mL), water, dried (Na2SO4), ®ltered and concentrated
to obtain a syrupy residue which was ®ltered on a bed of
silica gel (hexane:EtOAc 2:1) to yield the title compound
41 (2.6 g, 84%) as a syrup. [a]d 26.0 (c 1.2, CHCl3). 1H
NMR (CDCl3); d 1.2, 1.48 (6H, 2s, 2xCH3), 2.95, 3.03
(6H, 2s, 2ÂSCH3), 4.05 (1H, d, J 4.6, H-6), 4.23±4.90
(8H, m, H-1, 10, 2, 3, 4, 5 and CH2Ph), 4.95 (1H, H-7),
7.13±7.44 (10H, m, ArH). Anal. calcd for C25H32O10S2:
C,53.93; H, 5.79%. Found: C, 53.89; H, 5.68.
1
1.0, CHCl3). H NMR (CDCl3); d 1.3, 1.38, 1.45, 1.48
(12H, 4s, 4ÂCH3), 3.78±4.05 (5H, m, H-1,10,2,3,4,6), 4.6
(1H, d, J 3.9, H-5), 4.8 (1H, dd, J 3.9, 4.2, H-4), 6.1 (1H,
d, J 6.75, H-7), 7.31±7.5 (5H, m, ArH), 8.1±8.4 (4H, m,
ArH). Anal. calcd for C26H29NO9: C, 62.51; H, 5.85, N,
2.86%. Found: C, 62.45; H, 5.81, N, 2.82.
(7S)-3,6-Anhydro-1,2:4,5-di-O-isopropylidene-7-C-phenyl-
D-glycero-D-manno-eptitol (38). To a solution of 36 (4.1
g, 8.2 mmol) in methanol (20 mL) was added sodium
methoxide (prepared from 0.37 g sodium in 20 mL
methanol) and stirred for 1.5 h. After completion of the
reaction it was neutralised with carbon dioxide and sol-
vent removed in vacuo to obtain a residue which was
®ltered on a bed of silica gel (hexane:EtOAc 2:1) to
yield the title compound 38 (2.6 g, 93%) as a syrup. [a]d
36.0 (c 0.9, CHCl3). 1H NMR (CDCl3) 1.28,1.37,1.5
(12H, 4s, 4ÂCH3), 2.1 (1H, d, J 2.1, OH), 3.9±4.4(5H,
m, H-1,10,2,3,6), 4.77±4.90(3H, m, H-4,5,7), 7.2±7.45
(5H, m, ArH). Anal. calcd for C19H22O6: C, 65.12 ; H,
7.48%. Found: C, 65.04; H, 7.39.
(7S)-3,6-Anhydro-7-O-benzyl-1,2-dideoxy-4,5-O-isopropyl-
idene-7-C-phenyl-D-altro-hept-1-enitol (42). A solution of
41 (2.5 g, 4.4 mmol) in butan-2-one (50 mL) containing
sodium iodide (2.69 g, 17.9 mmol) was re¯uxed for 12 h.
After completion of the reaction solvent was removed in
vacuo to obtain a residue which was extracted into diethyl
ether (2Â100 mL). Combined organic phases were
separated washed with aqueous sodium thiosulphate
solution (75 mL), water, dried (Na2SO4) and con-
centrated under reduced pressure to obtain a residue
which was ®ltered on a bed of silica gel (hexane:EtOAc
4:1) to yield the title compound 42 (1.37 g, 85% ) as a
syrup. [a]d 59.0 (c 1.4, CHCl3).1H NMR CDCl3); d 1.2,
1.31 (6H, 2s, 2ÂCH3), 4.1 (1H, d, J 4.4, H-6), 4.3 (1H,
d, J 12.8, CH2Ph), 4.35±4.80(4H, m, H-4, 5,7), 4.95 (1H,
(7S)-3,6-Anhydro-7-O-benzyl-1,2:4,5-di-O-isopropylidene-
7-C-phenyl-D-glycero-D-manno-heptitol (39). To a slurry
of hexane washed sodium hydride (0.27 g, 11.4 mmol) in
DMF (5 ml) was added a solution of compound 38
(2.5 g, 7.14 mmol) in DMF (5 mL) at 0ꢀC followed by
the addition of benzyl bromide (1.69 g, 9.9 mmol). The
reaction mixture was stirred for 30 min at room

2102
H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
dd, J 3.8, 3.4, H-3), 5.18 (1H, dd, J 9.88, 1.2, H-1), 5.29
(1H, dd, J 16.5, 1.9, H-10), 5.75±5.95(1H, m, H-2) 7.15±
7.45 (10H, m, ArH). Anal. calcd for C23H26O4 : C,75.38;
H, 7.15%. Found: C, 75.29; H, 7.12.
for 3 h. After completion of the reaction the catalyst was
®ltered o€ and solvent was removed in vacuo to obtain
the title compound 16 (0.31 g, 84%) as white crystalline
solid. Mp 118±120ꢀC. [a]d 58.0 (c 0.8, MeOH). IR
1
n
max(KBr).1782 cm . H NMR (CDCl3); d 2.16 (1H,
(7S)- 3,6-Anhydro-7-O-benzyl-1,2 dideoxy-7-C-phenyl-D-
altro-hept-1-enitol (19). To a solution of 42 (1.3 g, 3.55
mmol) in 1,4-dioxane (10 ml) was added 5% aq. sul-
phuric acid (1 ml) and re¯uxed for 1 h. After completion
of the reaction, solvent was removed in vacuo and to
obtain a residue which was extracted into ethyl acetate.
Organic phase was washed with satd. NaHCO3 solution,
water, dried (Na2SO4), ®ltered and concentrated to
obtain the title compound 19 (0.99 g, 86%) as a white
crystalline solid. Mp 108±110ꢀC. [a]d 52.0 (c, 0.95,
CHCl3). 1H NMR (CDCl3); d 2.4 (1H, br.s, OH), 2.5 (1H,
br.s, OH), 4.05±4.7 (7H, m, H-3-7 and CH2Ph), 5.25 (1H,
dd, J 9.9, 1.0, H-1), 5.34 (1H, dd, J 16.6, 1.5, H-10), 5.85±
6.05 (1H, m, H-2), 7.2±7.55 (10H, m, ArH). 13C NMR
(CDCl3, 100MHz) d 70.9 (C-4), 73.3 (C-5), 74.17 (C-6),
82.0 (C-3),82.4(OCH2Ph), 85.1 (C-7), 118.3 (C-1), 127.3±
138.0 (C-2 and Aromatic). Anal. calcd for C20H22O4: C,
73.60; H, 6.79%. Found: C, 73.57; H, 6.75.
br.s, OH), 2.52 (1H, br.s, OH), 2.72 (1H, d, J 17.2, H-2),
2.76 (1H, dd, J 17.2, 6.1, H-20), 4.02 (1H, dd, J 4.2,4.6,
H-6), 4.35, (1H, m, H-5), 4.84 (1H, ddd, J 5.7, 4.3, 1.5,
H-3), 4.96 (2H, m, H-4, 7), 7.15±7.4 (5H, m, ArH). 13C
NMR (CDCl3, 100MHz) d 36.3 (C-2), 71.9 (C-5), 73.4
(C-3), 75.6 (C-6), 82.8 (C-4), 85.0 (C-7), 126.9±140.2
(Aromatic), 175.1 (CˆO). Anal. calcd for C13H14O5: C,
62.39; H, 5.64%. Found C, 62.31; H, 5.58.
3,6-Anhydro-2-deoxy-5,7-di-O-benzyl-7-C-[4-methoxy-
phenylmethyl]-D-ido-1,4-heptanolactone (46). To a stirred
solution of lactol 21 (0.7 g, 1.61 mmol) in methanol (10
mL) at 0ꢀC was added carboethoxymethylene triphenyl-
phosporane (1.12 g, 3.2 mmol) and stirred for 4 h. After
completion of the reaction solvent was removed under
reduced pressure to obtain a residue which was ®ltered
on a bed of silica gel (hexane:EtOAc 1:1) to yield the
title compound 46 (0.63 g, 82%) as a thick syrup. [a]d.
1
12.0 (c 1.2, CHCl3). IR nmax (KBr). 1780 cm 1. H
(7S)- 3,6-Anhydro-7-O-benzyl-2-deoxy-7-C-phenyl-D-altro-
1,4-heptanolactol (43). To a solution of 19 (0.95 g, 2.9
mmol) in aqueous DMF (20%) was added palladium
(II) chloride (0.10 g, 0.58 mmol), copper (I) chloride
(0.29 g, 2.9 mmol) and oxygen was bubbled for 3 h at
room temperature. After completion of the reaction it
was diluted with 2% aqueous HCl and extracted into
diethyl ether (2Â80 mL). Combined ethereal solution
was washed with water, dried, ®ltered and concentrated
to obtain the title compound 43 (0.84 g,85%) as a syrup.
1H NMR (CDCl3); d 175 (1H, br.s, OH), 2.02±2.3 (2H,
m, H-2, 20), 3.3 (1H, br.s, OH), 3.9±4.93 (7H, m, H-3-7
and CH2Ph), 5.48±5.7 (1H, m, a/b) 7.15±7.45 (10H, m,
ArH). Anal. calcd for C20H22O5: C, 70.16; H, 6.48%.
Found: C, 70.11; H, 6.43.
NMR (CDCl3); d 2.5±3.2 (4H, m, H-2, 20, 8.80), 3.8 (3H,
s, OMe), 3.6±5.05 (9H, m, H-3-7 and 2xCH2Ph), 6.8±7.4
(14H, m, ArH). Anal. calcd for C29H30O6: C, 73.40; H,
6.37%. Found: C, 73.37; H, 6.33.
3,6-Anhydro-2-deoxy-7-C-[4-methoxyphenylmethyl]-D-ido-
1,4-heptanolactone (17). Compound 36 (0.6 g, 1.2 mmol)
was dissolved in methanol (10 mL), 10% Pd/C (30 mg)
was added and stirred under hydrogen atmosphere (1
atm) for 4 h. The catalyst was ®ltered o€ and solvent
removed in vacuo to obtain the title compound 8 (0.3 g,
86%) as white crystalline solid. Mp 49±51ꢀC. IR nmax
1
(KBr).1782 cm 1. H NMR (CDCl3); d 2.4 (1H, br.s,
OH), 2.6±3.0 (4H, m, H-2,20, 8.80), 3.78 (3H, s, OCH3),
3.9 (1H, dd, J 2.6, 4.7, H-6), 4.10 (1H, d, J 2.6, H-5),
4.25 (1H, m, H-7), 4.6 (1H, br.s, OH), 4.9 (1H, d, J 4.2,
H-4), 5.05 (1H, m, H-3), 6.8 (2H, d, J 8.0, ArH), 7.15
(2H, d, J 8.0, ArH). 13C NMR (CDCl3, 50MHz) d 29.6
(C-8), 36.1 (C-2), 38.8 (OCH3), 72.2 (C-5), 74.8 (C-3), 76.9
(C-6), 81.6 (C-7), 87.8 (C-4), 114.2±130.2 (Aromatic),
175.1 (CˆO). Anal. calcd for C15H18O6: C, 61.21; H,
6.17%. Found: C, 61.17; H, 6.14.
(7S)- 3,6-Anhydro-7-O-benzyl-2-deoxy-7-C-phenyl-D-altro-
1,4-heptanolactone (44). To a solution of the lactol 43
(0.8 g, 2.3 mmol) in dry CH2Cl2 (15 mL) was added
powdered 4Aꢀmolecular seives (20 mg), pyridinium
dichromate (1 g, 2.8 mmol) and re¯uxed for 1.5 h. After
completion of the reaction solvent was removed to
obtain a residue. The residue was extracted into diethyl
ether (50 mL) ®ltered on a bed of silica gel ®rst by elut-
ing with diethyl ether followed by hexane:EtOAc (1:1)
to obtain the title compound 44 (0.61 g, 77%) as a white
crystalline solid. Mp 102±104ꢀC. [a]d. 2.25 (c 1.3,
CHCl3). IR nmax(KBr).1782 cm 1. 1H NMR (CDCl3); d
2.35, (1H, br.d, OH), 2.65±2.75 (2H, m, H-2), 4.05 (1H,
dd, J 4.5, 4.65, H-6), 4.18±4.4 (4H, m, H-5 and CH2Ph),
4.52 (1H, d, J 5.6, H-7), 4.59 (1H, d, J 11.2, CH2Ph),
4.72±4.85(1H, m, H-3), 4.9 (1H, dt, J 4.2, 4.1, H-4),
7.18±7.5 (10H, m, ArH). Anal. calcd for C20H20O5:
C,70.57; H, 5.92%. Found: C, 70.51; H, 5.88.
Antitumour assay
In screening, each compound was tested over a broad
concentration range (tenfold dilutions starting from
5100 to 10 mM) against 6 human cancer cell lines
comprised of di€erent tumor types maintained in growing
condition in RPMI 1640 medium containing 10% foetal
calf serum and incubated at 37ꢀC under 5% CO2 atmo-
sphere. All cell lines were inoculated onto a series of
standard 96-well microtitre plate on day zero, followed
by twenty-four hour incubation in the absence of test
compound. The inoculation density used in the screen
38
(7S)-3,6-Anhydro-2-deoxy-7-C-phenyl-D-altro-1,4-heptanol-
actone (16). Compound 44 (0.5 g, 1.4 mmol) was dis-
solved in ethyl acetate (10 mL), 10% Pd/C (30 mg ) was
added and stirred under hydrogen atmosphere (1 atm)
was as per Monk et al. All the new compounds were
dissolved in DMSO and diluted further in culture medium.
An aliquot of each dilution was added to the growing
cells in 96 well plates and incubated for 48 h. After

H. B. Mereyala et al. / Bioorg. Med. Chem. 7 (1999) 2095±2103
2103
incubation, the assay was terminated by adding 50 mL
of trichloroacetic acid (TCA) and incubating at 4ꢀC for
30 min. The precipitated cells were washed and stained
with sulforhodamine B dye for 30 min and the excess
dye washed o€ with acetic acid. Adsorbed dye was
solubilised in Tris base (alkaline pH) and quantitated by
measuring the OD at 490 nm in an ELISA reader. Gl50
concentration which inhibits the cell growth by 50%
was calculated according to Boyd and Paull.39
14. Yang, Z. C.; Zhou, W. S. J. Chem. Soc., Perkin Trans.
1994, 1, 323.
15. Xu, D.; Sharpless, K. B. Tetrahedron Lett. 1994, 35, 4685.
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18. Ko, S. Y.; Lerpiniere, J. Tetrahedron Lett. 1995, 36, 2101.
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20. Mukai, C.; Kim, I. J.; Kido, M.; Hanaoka, M. Tetrahedron
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Acknowledgements
23. Tsubuki, M.; Kanai, K.; Nagase, H.; Honda, T. Tetra-
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R. R. G. and M. J thank U.G.C and C.S.I.R, respec-
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25. Gracza, T.; Jager, V. Synthesis 1994, 1359.
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