Synthesis, biological, and chiroptical activity of 3-phenyl-clavams

Article abstract of DOI:10.1016/j.bmc.2003.10.043

The [2+2]cycloaddition of chlorosulfonyl isocyanate to simple vinyl ethers derived from the 2-O-sulfonylated (R) and (S) 1-phenyl-1,2-ethanediol leads to 4-alkoxy-azetidin-2-ones with a moderate stereoselectivity. The cycloaddition to analogous (Z)-propenyl ethers proceeds stereospecifically with the retention of the olefin configuration. The intramolecular alkylation of β-lactam nitrogen atom furnished all possible stereoisomers of 3-phenyl- and 6-methyl-3-phenyl-clavams. The biological and chiroptical activity of synthesized clavams was investigated. The (3R,5R)-diastereomer 30 showed higher inhibition of bacterial enzymes than other related compounds.

Full text of DOI:10.1016/j.bmc.2003.10.043

Bioorganic & Medicinal Chemistry 12 (2004) 405–416
Synthesis, biological, and chiroptical activity of 3-phenyl-clavams
Maciej Cierpucha,a Jolanta Solecka,b Jadwiga Frelek,a Patrycja Szczukiewicza
and Marek Chmielewskia,*
aInstitute of Organic Chemistry of the Polish Academy of Sciences, 01-224 Warsaw, Poland
bNational Institute of Hygiene,00-791 Warsaw, Poland
Received 1 September 2003; accepted 22 October 2003
Abstract—The [2+2]cycloaddition of chlorosulfonyl isocyanate to simple vinyl ethers derived from the 2-O-sulfonylated (R) and
(S) 1-phenyl-1,2-ethanediol leads to 4-alkoxy-azetidin-2-ones with a moderate stereoselectivity. The cycloaddition to analogous (Z)-
propenyl ethers proceeds stereospecifically with the retention of the olefin configuration. The intramolecular alkylation of b-lactam
nitrogen atom furnished all possible stereoisomers of 3-phenyl- and 6-methyl-3-phenyl-clavams. The biological and chiroptical
activity of synthesized clavams was investigated. The (3R,5R)-diastereomer 30 showed higher inhibition of bacterial enzymes than
other related compounds.
# 2003 Elsevier Ltd. All rights reserved.
1. Introduction
atom in the intermediary 4-alkoxy-azetidinone. The
drawback of such a strategy is related to a low asym-
While a number of different clavams were isolated,1ꢀ5
only clavulanic acid 11 and its simple O-acyl derivatives
with the (5R)-configuration at the ring junction offer the
strong b-lactamase inhibition and a weak antibacterial
activity. Certain other clavams, represented by the
family 2–5, with (S)-configuration at C-5, exhibit activ-
ity against a number species of fungi.2ꢀ5
metric induction at C-4 of the azetidin-2-one ring.6ꢀ10
The [2+2]cycloaddition of chlorosulfonyl isocyanate (CSI)
to chiral vinyl ethers, having a stereogenic center located
next to the oxygen atom, offers an alternative to that which
is based on the condensation of 6 with chiral alcohols.10ꢀ13
It has been demonstrated that the [2+2]cycloaddition
method is stereospecific and provides the excellent stereo-
selectivity even in the case of open-chain vinyl ethers.14,15
A few years ago we synthesized, starting from (L)-tartaric
acid, clavam 13, structurally related to the clavulanic acid
1 missing the C-2 carboxylic function.15 Compound 13
displayed marked anti b-lactamase activity.
Since the 1-phenyl-1,2-ethanediol (14) is commercially
available in both enantiomeric forms, it was of interest
to investigate the [2+2]cycloaddition to its 1-O-vinyl
and (Z) 1-O-propenyl ethers and to synthesize the cor-
responding 3-phenyl-clavams via intramolecular alkyl-
ation of the nitrogen atom in intermediary adducts, as
well as examine the biological activity of all possible
stereoisomeric clavams formed.
Compounds 1–5 lack substituent at C-6 carbon atom
and, consequently, their syntheses usually begin with the
commercially available 4-acetoxy-azetidinone 6 as a
convenient starting material.6ꢀ9 The condensation of 6
with a separately prepared chiral alcohol has been fol-
lowed by the intramolecular alkylation of the nitrogen
2. Results and discussion
Keywords: Clavams; CD-spectroscopy; [2+2]cycloaddition of chloro-
sulfonyl isocyanate.
* Corresponding author. Tel.: +48-22-6323789; fax: +48-22-6326681;
e-mail: chmiel@icho.edu.pl
Our previous studies performed on the vinyl ethers 814
and 9,15 substituted at C-1 with a five-membered ring
0968-0896/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2003.10.043

406
M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
Scheme 1.
and protected at the primary hydroxyl group with the
triisopropylbenzenesulfonyl (TIBS) group, demon-
strated the high stereoselectivity of [2+2]cycloaddition
(Scheme 1). We have established the existence of oppo-
site (S) and (R) configurations at C-40 in products 10
and 11, respectively, depending on the (R) and (S) con-
figuration at the carbon atom bearing vinyloxy group in
the starting material. Therefore, we expected that the
replacement of five-membered ring (furanoid or dioxo-
lane) with the phenyl ring should not change the high
asymmetric induction. The primary hydroxyl group
was protected by formation of the sulfonyl group. In
order to compare the influence of bulkiness of sulfonyl
groups on the diastereoselectivity of cycloaddition, we
tested the mesyl, isopropanesulfonyl (IPS), 1,1-dime-
thyl-2-phenyl-ethanesulfonyl (BIPS) and triisopro-
pylbenzenesulfonyl (TIBS) protective groups. The BIPS
group was obtained according to the procedure devel-
oped by Musicki and Widlanski16 for the C-alkylation
of mesylates. The experimental protocol consisted of
lithiation of the isopropyl group of the sulfonate fol-
lowed by alkylation of the resulting salt with benzyl
chloride.
The [2+2]cycloaddition of CSI to the vinyl ethers 18–
2018 proceeds with a moderate diastereoselectivity
yielding 22, 24 and 26 as the main components of the
corresponding post-reaction mixtures (Table 1); in other
words, the defined absolute configuration (R or S) of
the vinyl ether generates opposite absolute configur-
ation at C-40 of the azetidin-2-one ring (S or R, respec-
tively). In the case of addition to 21, the direction of
asymmetric induction was changed. In this case the
compound 29 become the main product (Table 1); it
means that defined absolute configuration of the vinyl
ether generates the same absolute configuration at C-40
of the azetidin-2-one ring.
Mixtures 22/23 and 28/29 (SR and SS) were not sepa-
rated into pure components and were used directly in
the next step, whereas analogous mixtures 24/25 and 26/
27 were successfully separated into pure diastereomers by
chromatography prior to subsequent transformations.
The intramolecular N-alkylation in 22–29 proceeds
under standard the PTC conditions to provide corres-
ponding mixture of clavams 30 and 31, or pure diaster-
eomers 32 and 33. Mixture of 30 and 31 was separated
into pure components by chromatography. The con-
figuration of stereoisomers 30–33 was established ana-
The enantiomers 14 (R) and 14 (S) were independently
transformed into corresponding vinyl ethers 18, 19 and
21 using standard reaction sequence. The sequence
consisted of sulfonylation at the primary hydroxy group
followed by the trans-etherification procedure with vinyl
n-butyl ether in the presence of mercury acetate.17 The
vinyl ether 20 was obtained from 19 using Musicki and
Widlanski method.16
1
lysing NOE’s in H NMR spectra11ꢀ15,19 (protons H-3
and H-5 display spin–spin interaction in the case of
3R5S or 3S5R diastereomers whereas for 3R5R or 3S5S
analogous spin–spin interactions were not detected) and
circular dichroism spectra (see over).
The (Z)-propenyl ethers 38, 39 and 41 were obtained
following the standard reaction sequence (Scheme 2).
Following tritylation of the primary hydroxy group and
alkylation of the secondary one, the trityl substituent
was removed and allyl ether 36 was rearranged to the
(Z)-propenyl 37 by treatment with t-BuOK in DMSO.20
The free hydroxy group was subsequently sulfonylated
using the same methodology as employed during pre-
paration of compounds 15, 16 and 18. Compound 40
was obtained from 39 by the method used for 20.16
Table 1. Proportions of stereisomers 22/23, 24/25, 26/27, 28/29 and
42/43, 44/45, 46/47, 48/49 obtained by [2+2]cycloaddition of CSI to
vinyl ethers 18–21 and (Z)-propenyl ethers 38–4118
Substrate
Proportions of diastereomers (1R,40S)
versus (1R,40R) or (1S,40R) versus (1S,40S)
18
19
20
21
38
39
40
41
1.9:1
2:1
3:1
1:2.4
1:1
1:1.35
1:1.15
1:10
The comparison of CSI [2+2]cycloaddition to vinyl
ethers 18–20 with analogous addition to (Z)-propenyl
ethers 38–40 shows that the direction of asymmetric
induction in both sets of reactions is opposite.18 The

M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
407
of addition to 38–40 is low, in contrast to the case of
TIBS substituted ether 41, where it was found to be
excellent.18 The diastereomeric mixtures 42/43, 44/45,
46/47 and 48/49 were separated into pure components
using chromatography.
To confirm assignment of the absolute configuration at
C-4 in 4-alkoxy-azetidinones 24–27 and 38–49, the CD
spectroscopy was used. The assignment of absolute
configuration was based on the b-lactam sector rule.21
Recently, the b-lactam sector rule was applied success-
fully to the configurational assignments of mono-
bactams, that are differently substituted at C-3 and C-4
atoms.22 According to the rule, a negative sign of the
CD band occurring around 220 nm corresponds to the
(4R) and a positive sign of the same band to the (4S)
configuration. Following this finding, the absolute con-
figuration at C-4 can be established as (R) for azetidi-
nones 25, 27, 42, 44, 46, and 48 displaying a negative
long-wavelength CD band, whereas a positive Cotton
effect (CE) around 220 nm in compounds 24, 26, 43, 45,
47, and 49 indicates the (S) absolute configuration at the
same carbon atom (see Experimental). This assignment
nicely corroborates the prediction made by analysis of
the NMR data. To illustrate, the CD spectra of repre-
sentative 4-alkoxy-azetidinones are presented in Figure
1. These spectra appear almost enantiomeric for local
enantiomers 24, 25 and 46, 47.
diastereomers with the same absolute configuration at
C-1 and C-40 carbon atoms (1R40R: 42, 44 and 1S40S:
47, 49) are found as a main components of the post-
reaction mixtures. The diastereomeric excess in the case
The intramolecular alkylation of b-lactam nitrogen atom
in compounds 42–49 led to the corresponding clavams 50–
Scheme 2.

408
M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
to C-10 of the olefin (Fig. 3a). A streochemical model of
the transition state for [2+2]cycloaddition of CSI and
vinyl ethers based on the conformation depicted in Fig-
ure 3a has been recently proposed by us.26 The CSI
molecule approaches the double bond syn to the phenyl
group. This directional preference is not very large and
is amplified if the size of the sulfonyl group is increased.
In the case of (Z)-propenyl ethers, the rationalization of
the experimental findings is not fully consistent. One
can postulate a change of the preferred conformation of
the transition state to the s-trans with H-1 proton loca-
ted in diastereozero-plane, syn-periplanar to C-10 of the
olefin (compare Fig. 3a with Fig. 3c). The chirality cen-
ter rotates around the C–O bond by 180ꢁ. The preferred
approach of CSI molecule is the same as in the case of
simple vinyl ether. This leads to the reverse direction
of asymmetric induction and consequently to the lower
diastereomeric excess, since the double bond is at a
greater distance to both large substituents. In the case of
TIBS substituent (ethers 21 and 41), the complexation
of both aromatic rings changes geometry of the transi-
tion state; both large substituents are closer each other
(Fig. 3b and 3c). It could be assumed that the preferred
conformation of the transition state for both simple
vinyl ether and (Z)-propenyl ether, in such case, is
similar. This assumption can explain the change of
direction of asymmetric induction in the case of the
vinyl ether 21 (Fig. 3b) in comparison with related
ethers 18–20 (Fig. 3a). Similar conformation of the
transition state for the ether 21 and 41, however, does
not explain a significant difference in asymmetric
induction of cycloaddition between simple vinyl ether 21
(1:2.4) versus Z-propenyl 41 (1:10) (Table 1).
...........
... ...
–),
Figure 1. CD spectra of azetidinones 24 (
and 47 (—) recorded in acetonitrile.
), 25 (- - -), 46 (–
–
53. The configuration of all stereoisomeric clavams 50–53
was established analogously as for compounds 30–33.
The absolute configuration of clavams 30–33 and 50–53
was also determined by the analysis of their respective
circular dichroic spectra. It was previously shown that
the absolute configuration at the bridge-head carbon
atom determines the sign of the CD of penicillins,
cephalosphorins, penams and clavams.23 Very recently,
a simple helicity rule for the assignment of absolute
configuration at the ring junction carbon atom by
correlation with the sign of the CD band associated
with the n–p* transition was proposed for clavams and
5-oxacephams.24
The application of the aforementioned helicity rule to
clavams 30–33 and 50–53 leads to the conclusion that
the absolute configuration at C-5 atom in compounds
30, 32, 50, and 52, characterized by a positive CD band
attributed to the n–p* b-lactam amide transition, is (R) (see
Experimental). The negative sign of the same CE indicates
the (5S) absolute configuration for clavams 31, 33, 51, and
53 (see Experimental). Such assignment is consistent with
the stereochemical conclusions based on application of
other spectroscopic methods, for example, NMR spectro-
scopy. As an example, two pairs of representative diaster-
eomers 32, 33 and 50, 51 are shown in Figure 2.
Clavams 30–33 and 50–53 were evaluated for their bio-
logical activity. An inhibition of the DD-carboxy-
The analysis of results of cycloaddition may suggest the
change of the preferred conformation of the ether group
in the transition state when the simple vinyl ether is
replaced by the (Z)-propenyl moiety. In the past we
have not noticed such a phenomenon.13,25 In the case of
a simple vinyl ether the preferred conformation of the
transition state is probably s-trans with the H-1 proton
located within the diastereozero-plane, anti-periplanar
Figure 3. Preferred stereochemical pathway for cycloaddition of CSI
to vinyl ethers and Z-propenyl ethers. For the sake of simplicity, con-
figuration of substrates refer to (R) series only..18
...........
Figure 2. CD spectra of clavams 32 (—), 33 (– - - -), 50 (
... ... ...
), and
51 (–
– – ) recorded in acetonitrile.

M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
Table 2. Biological activity of 3-phenyl-clavams 30, 31 and 50–53
409
4.1. General procedure of sulfonylation
Compd
Inhibition of
DD-peptidase ID50 (M)
Inhibition of
b-lactamase IC50 (M)
To a solution of (1S) or (1R) 1-phenyl-1,2-ethanediol
(14) (0.5 g, 3.62 mmol) and Et3N (0.75 mL, 5.43 mmol)
in CH2Cl2 (10 mL) the sulfonyl chloride (3.98 mmol)
was added at 0 ꢁC. After 13 h at 10 ꢁC the reaction
mixture was diluted with water (50 mL). The solution
was extracted with diethyl ether (3Â40 mL). The com-
bined organic extracts were dried with magnesium sul-
fate, filtered and concentrated to dryness. The residue
was purified by a column chromatography on silica gel
using hexane–ethyl acetate 19:1 (v/v) as eluent, to give
corresponding sulfonate.
ꢀ3
ꢀ2
.
0.18 10
—
.
.
.
.
30
31
50
51
52
53
0.88 10ꢀ1
0.80 10ꢀ2
ꢀ2
.
0.42 10
0.95 10ꢀ1
—
—
—
0.76 10ꢀ1
.
0.69 10ꢀ1
.
0.26 10
peptidase activity and, separately, an inhibition of b-
lactamase were measured (Table 2).27ꢀ29 Compounds
31–33 and 51–53 showed only a trace of DD-peptidase
inhibition. Within studied series only compound 30
(R,R) showed inhibition of DD-peptidase, whereas its 6-
methyl congener 50 (R,R) showed significantly lower
activity. Clavams not placed in Table 2, 32 and 33,
exhibited lack of b-lactamase inhibition (32) or a min
only (33). All tested clavams were not soluble in water,
so enzymatic tests were done in 25% of methanol. In
higher concentration of methanol in reaction mixture
both enzymes lost of activity.
4.1.1. (1R) 2-O-Methanesulfonyl-1-phenyl-1,2-ethanediol
(15). Yield: 88%; Rf (hexane–ethyl acetate v/v 1:1) 0.5;
[a]D ꢀ62.0 (c 0.9, CH2Cl2); IR (film): 1352 cmꢀ1 (S¼O),
3524 cmꢀ1 (OH); 1H NMR (CDCl3): d 3.03 (s, 3H, Ms),
4.28 (dd, 1H, J=10.9, 8.2 Hz, H-2), 4.34 (dd, 1H,
J=10.9, 3.4 Hz, H-20), 5.05 (dd, 1H, J=8.2, 3.4 Hz, H-
1), 7.31–7.47 (m, 5H, Aryl); 13C NMR (CDCl3): d 37.62,
72.13, 73.91, 126.18, 128.68, 128.77, 138.33. ESIHRMS,
m/z; (M+Na)+ calcd for C9H12O4SNa: 239.0349.
Found: 239.0339.
4.1.2. (1R) 2-O-Isopropanesulfonyl-1-phenyl-1,2-ethane-
diol (16). Yield: 74%; mp 45.5–46.7 ꢁC; Rf (hexane–
ethyl acetate v/v 1:1) 0.8; [a]D ꢀ50.1 (c 0.7, CH2Cl2); IR
3. Conclusion
It was shown that the [2+2]cycloaddition of CSI to
ethers 18–21 and 38–41 proceeds with a low stereo-
selectivity. Analogous cyclo-additions to 38–41 are ste-
reospecific. Vinyl ethers 18–20 and (Z)-propenyl ethers
38–41 displayed opposite directions of asymmetric
induction. Interaction between phenyl and arylsulfonyl
groups causes that ether 21 exhibits the same direction
of asymmetric induction as (Z)-propenyl ethers. We
demonstrated that the circular dichroism spectroscopy
is a very useful tool for the assignment of the absolute
configuration of clavams bearing a phenyl group at C-3.
Only one clavam, with the (3R,5R) configuration shows
an interesting inhibition of DD-peptidase, but lower
1
(film): 1346 cmꢀ1 (S¼O), 3518 cmꢀ1 (OH); H NMR
(CDCl3): d 1.42, 1.43 (2xd, 6H, J=6.9 Hz, isopr.), 3.34
(sept., 1H, J=6.9 Hz, isopr.), 4.27 (dd, 1H, J=11.0, 8.4
Hz, H-2), 4.34 (dd, 1H, J=11.0, 3.4 Hz, H-20), 5.05 (dd,
1H, J=8.4, 3.4 Hz, H-1), 7.31–7.42 (m, 5H, Aryl); 13C
NMR (400 MHz, CDCl3): d 16.53, 16.62, 52.45, 72.33,
73.51, 126.20, 128.58, 128.71, 138.45; ESIHRMS, m/z;
(M+Na)+ calcd for C11H16O4SNa: 267.0662. Found:
267.0661. Anal. calcd for C11H16O4S: C, 54.08; H, 6.60;
S, 13.12. Found: C, 54.18; H, 6.81; S, 13.04.
4.1.3. (1S) 1-Phenyl-2-O-(2,4,6-triisopropylbenzenesulfo-
nyl)-1,2-ethanediol (17). Yield: 83%; Rf (hexane–ethyl
acetate v/v 9:1) 0.25; mp 193–195 ꢁC; [a]D +35.2 (c 1.2,
CH2Cl2); IR (film): 3527 cmꢀ1 (OH); 1H NMR
(CDCl3): d 1.25 (bd, 18H, J=6.9 Hz, TIBS), 2.91 (sept.,
1H, J=6.9 Hz, TIBS), 4.10 (dd, 1H, J=10.7, 8.7 Hz, H-
2), 4.14 (sept., 2H, J=6.9 Hz, TIBS), 4.17 (dd, 1H,
J=3.2, 10.7 Hz, H-2), 5.06 (dd, 1H, J=8.7, 3.2 Hz, H-
1), 7.18 (s, 2H, TIBS), 7.30–7.35 (m, 5H, Aryl); 13C
NMR (CDCl3): d 23.50, 24.68, 24.72, 29.69, 34.25,
72.21, 73.63, 123.86, 126.22, 128.50, 128.68, 129.17,
138.42, 150.89, 153.98; ESIHRMS, m/z; (M+Na)+
calcd for C23H32O4SNa: 427.1914. Found: 427.1935.
than known inhibitors sulbactam (ID50 (M)=5.5 10ꢀ4),
.
or clavulanic acid (ID50 (M)=2.0 10ꢀ5).30
.
4. Experimental
Melting points were determined on a Koefler hot-stage
apparatus. NMR spectra were recorded using Brucker
Avance 500 and Varian Mercury 400 instruments. IR
spectra were recorded on a Perkin–Elmer FTIR Spec-
trum 200 spectrophotometer. UV spectra were mea-
sured on a Cary 100 spectrophotometer in acetonitrile.
CD spectra were recorded between 180–400 nm at
room temperature with a JASCO J-715 spectro-
polarimeter using acetonitrile solutions. Solutions with
concentrations in the range 0.8Â10ꢀ4 to 1.2Â10ꢀ3
4.2. General procedure of trans-vinylation
A solution of sulfonate (15, 16 or 17, 2.28 mmol) and
mercury(II) acetate (0.03 g) in butyl vinyl ether (30 mL)
was refluxed for 1 h. The solution was cooled, washed with
saturated aqueous sodium carbonate (2Â), dried with
magnesium sulfate, filtered and concentrated to dryness.
The residue was purified by a column chromatography
on silica gel using hexane–ethyl acetate 9:1 (v/v) as an
eluent, to give corresponding vinyl ether (18, 19, 21).
mol dmꢀ3 were examined in cells with path length 0.1 or
.
1 cm. Optical rotations were measured using a JASCO P
3010 polarimeter at 22Æ3 ꢁC. Mass spectra were recor-
ded using AMD-604 Inectra GmbH and HPLC-MS
with Mariner and API 356 detectors. Column chroma-
tography was performed using E. Merck Kiesel Gel
(230–400 mesh).

410
M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
4.2.1. (1R) 2-O-Methanesulfonyl-1-phenyl-1-O-vinyl-1,2-
ethanediol (18). Yield: 69%; Rf (hexane–ethyl acetate v/
v3:1) 0.5; [ a]D ꢀ52.5 (c 1.5, CH2Cl2); IR (film): 1357
using hexane–ethyl acetate 3:1 (v/v) as eluent to obtain
20 (0.384 g, 73%); Rf (hexane–ethyl acetate v/v 3:1) 0.6;
[a]D ꢀ38.9 (c 1.8, CH2Cl2); IR (film): 1344 cmꢀ1 (S¼O),
1623 cmꢀ1, 1638 cmꢀ1 (C¼C); 1H NMR (CDCl3): d
1.33 (s, 6H, 2ÂCH3), 3.10 (s, 2H, CH2Ph), 4.07 (dd, 1H,
J=6.6, 2.2 Hz, H-20a), 4.30 (dd, 1H, J=14.1, 2.2 Hz, H-
20), 4.40 (m, 2H, H-2a,2b), 5.10 (dd, 1H, J=5.4, 6.3 Hz,
H-1), 6.38 (dd, 1H, J=14.1, 6.7 Hz, H-10), 7.11–7.20 (m,
2H, aryl), 7.23–7.45 (m, 8H, aryl); 13C NMR (CDCl3): d
20.97, 41.21, 63.41, 71.11, 78.97, 90.33, 126.59, 127.12,
128.21, 128.79, 128.82, 130.99, 134.82, 136.21, 150.11;
ESIHRMS, m/z; (M+Na)+ calcd for C20H24O4SNa:
383.1288. Found: 383.1305. Anal. calcd for C20H24O4S:
C, 66.64; H, 6.7; S, 8.89. Found: C, 66.58; H, 6.72; S,
8.94.
1
cmꢀ1 (S¼O), 1639 cmꢀ1, 1624 cmꢀ1 (C¼C); H NMR
(CDCl3): d 3.03 (s, 3H, Ms), 4.10 (dd, 1H, J=6.7, 2.2
Hz, H-20a), 4.30 (dd, 1H, J=14.1, 2.2 Hz, H-20b), 4.34
(dd, 1H, J=11.2, 3.7 Hz, H-2a), 4.44 (dd, 1H, J=11.2,
7.8 Hz, H-2b), 5.10 (dd, 1H, J=7.8, 3.7 Hz, 1H, H-1),
5.37 (dd, 1H, J=14.1, 6.7 Hz, 1H, H-10), 7.31–7.49 (m,
5H, aryl); 13C NMR (CDCl3): d 37.78, 71.99, 78.78,
90.64, 126.54, 2x128.90, 135.83, 149.83; ESIHRMS, m/
z; (M+Na)+ calcd for C11H14O4SNa: 265.0505. Found:
265.0519
4.2.2. (1R) 2-O-Isopropanesulfonyl-1-phenyl-1-O-vinyl-
1,2-ethanediol (19). Yield: 72%; Rf (hexane–ethyl ace-
tate v/v 3:1) 0.5; [a]D ꢀ55.5 (c 1.9, CH2Cl2); IR (film):
4.3. General procedure of cycloaddition
1
1350 cmꢀ1 (S¼O), 1623 cmꢀ1, 1640 cmꢀ1 (C¼C); H
NMR (CDCl3): d 1.41 (2Âd, 6H, J=6.9, 1.5 Hz, isopr.),
3.33 (sept, 1H, J=6.9 Hz, isopr.), 4.06 (dd, 1H, J=6.6,
2.2 Hz, H-20a), 4.27 (dd, 1H, J=14.2, 2.2 Hz, H-20b),
4.32 (dd, 1H, J=11.3, 3.8 Hz, H-2a), 4.37 (dd, 1H,
J=11.3, 7.9 Hz, H-2b), 5.08 (dd, 1H, J=7.9, 3.8 Hz, H-
1), 6.36 (dd, 1H, J=14.2, 6.6 Hz, H-10), 7.30–7.42 (m,
5H, aryl); 13C NMR (CDCl3): d 16.46, 16.62, 52.46,
71.31, 78.89, 90.40, 125.53, 128.80, 128.83, 136.03,
149.94; ESIHRMS, m/z; (M+Na)+ calcd for
C13H18O4SNa: 293.0818. Found: 293.0830. Anal. calcd
for C13H18O4S: C, 57.76; H, 6.71; S, 11.86. Found: C,
57.70; H, 6.80; S, 11.92.
To a well stirred suspension of anhydrous sodium car-
bonate (0.2 g) in solution of vinyl ether (18–21, 1.23
mmol) in dry toluene (5 mL), the chlorosulfonyl isocy-
anate (139 mL, 1.6 mmol) was added within 5 min,
under an argon atmosphere at ꢀ50 ꢁC. The mixture was
stirred at the same temperature for another 25 min and
was diluted with toluene (5 mL) and cooled to ꢀ70 ꢁC.
The Red-Al solution in toluene (1M; 1.24 mL) was
slowly added and the reaction mixture was stirred for 15
min. The cooling bath was removed and water (0.2 mL)
was added at 0 ꢁC. Stirring was continued for additional
10 min. The suspension was filtered and solvent was
evaporated. The residue was purified by a column
chromatography on silica gel using hexane–ethyl acetate
1:1 (v/v) as eluent, to give a mixture of corresponding
diastereomers.
4.2.3. (1S) 1-Phenyl-2-O-(2,4,6-triisopropylbenzenesulfo-
nyl)-1-O-vinyl-1,2-ethanediol (21). Yield: 73%; Rf (2Â
hexane–tert-butyl-methyl ether v/v 19:1) 0.5; [a]D +57.6
(c 1.0, CH2Cl2); IR (film): 1622 cmꢀ1, 1639 cmꢀ1
(C¼C); H NMR (CDCl3): d 1.24 (d, 6H, J=6.8 Hz,
4.3.1. (1R,40S) and (1R,40R) 1-O-(Azetidin-20-on-40-yl)-2-
O-methanesulfonyl-1-phenyl-1,2-ethanediol (22 and 23).
Yield: 46%; Rf (hexane–ethyl acetate v/v 1:4) 0.3; IR
(film): 1352 cmꢀ1 (S¼O), 1768 cmꢀ1 (C¼O), 3352 cmꢀ1
1
TIBS), 1.26 (d, 12H, J=6.8 Hz, TIBS), 2.90 (sept, 1H,
J=6.8 Hz, TIBS), 3.98 (dd, 1H, J=6.7, 2.1 Hz, H-20a),
4.14 (sept, 2H, J=6.8 Hz, TIBS), 4.16 (dd, 1H, J=14.2,
2.1 Hz, H-20b), 4.19 (dd, 1H, J=11.1, 4.3 Hz, H-2a),
4.22 (dd, 1H, J=11.1, 7.5 Hz, H-2b), 5.05 (dd, 1H,
J=7.5, 4.3 Hz, H-1), 6.23 (dd, 1H, J=14.2, 6.7 Hz, H-
10), 7.18 (s, 2H, Aryl), 7.27–7.37 (m, 5H, aryl); 13C
NMR (500 MHz, CDCl3): d 23.34, 24.49, 24.54, 29.47,
34.07, 71.07, 78.58, 90.03, 123.58, 126.35, 128.50,
128.62, 129.40, 136.21, 149.7, 150.64, 153.54;
1
(NH); H NMR (CDCl3) selected signals: d 3.00 (s, 1H,
Ms of minor component), 3.03 (s, 2H, Ms of major
component), 5.11 (dd, 0.66H, J=11.5, 3.8 Hz, H-40 of
major component), 5.17 (dd, 0.33H, J=1.5, 3.8 Hz, H-
40 of minor component); ESIHRMS, m/z; (M+Na)+
calcd for C12H15NO5SNa: 308.0563. Found: 308.0555.
LSIMSHRMS m/z;
C25H34O4SNa: 453.2075 Found: 453.2092.
(M+Na)+:
calcd
for
4.3.2. (1R,40S) 1-O-(Azetidin-20-on-40-yl)-2-O-isopro-
pane-sulfonyl-1-phenyl-1,2-ethanediol (24). Rf (hexane–
ethyl acetate v/v 3:7) 0.4; [a]D ꢀ72.3 (c 0.8, CH2Cl2); IR
(film): 1347 cmꢀ1 (S¼O), 1770 cmꢀ1 (C¼O), 3340 cmꢀ1
(NH); IR (film): 1347 cmꢀ1 (S¼O), 1770 cmꢀ1 (C¼O),
4.2.4. (1R) 2-O-(10,10-Dimethyl-20-phenyl-ethanesulfo-
nyl)-1-phenyl-1-O-vinyl-1,2-ethanediol (20). Compound
19 (0.394 g, 1.46 mmol) was dissolved in THF/DMPU
mixture [5 mL; 5:1 (v/v)] and cooled to ꢀ78 ꢁC. The
n-BuLi (2.7 M; 0.81 mL, 2.19 mmol) was added drop-
wise under argon atmosphere. Solution was stirred for
10 min until a pale red color developed, then benzyl
bromide (0.31 mL, 2.63 mmol) was added. The tem-
perature was allowed rise up to ꢀ20 ꢁC. After 1 h reac-
tion was quenched with MeOH (1 mL). The solution
was extracted with t-butyl-methyl ether (3Â). The com-
bined organic extracts were dried with magnesium sul-
fate, filtered and concentrated to dryness. The residue
was purified by a column chromatography on silica gel
1
3340 cmꢀ1 (NH); H NMR (CDCl3): d 1.41, 1.43 (2Âd,
6H, J=6.8 Hz, isopr.), 2.88 (ddd, 1H, J=15.1, 1.6, 0.6
Hz, H-30a), 3.06 (ddd, 1H, J=15.1, 3.8, 2.5 Hz, H-30b),
3.33 (sept, 1H, J=6.8 Hz, isopr), 4.27 (dd, 1H, J=11.3,
7.2 Hz, H-2a), 4.32 (dd, 1H, J=11.3, 4.9 Hz, H-2b),
4.79 (dd, 1H, J=7.2, 4.9 Hz, H-1), 5.11 (dd, 1H, J=3.8,
1.6 Hz, H-40), 7.15–7.48 (m, 5H, aryl); 13C NMR
(CDCl3): d 16.48, 16.57, 45.85, 52.71, 71.50, 78.20,
79.09, 126.74, 128.98, 129.16, 135.96, 171.01; UV e
(lmax): 9200 (205sh), 4200 (216sh); CD Áe (lmax): ꢀ12.8
(190.4) +6.3 (219.8); ESIHRMS, m/z; (M+Na)+ calcd
for C14H19NO5SNa: 336.0876. Found: 336.0885.

M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
411
4.3.3. (1R,40R) 1-O-(Azetidin-20-on-40-yl)-2-O-isopro-
pane-sulfonyl-1-phenyl-1,2-ethanediol (25). Rf (hexane–
ethyl acetate v/v 3:7) 0.35; [a]D ꢀ48.2 (c 0.5, CH2Cl2);
IR (film): 1347 cmꢀ1 (S¼O), 1772 cmꢀ1 (C¼O), 3338
5.09 (dd, 1H, J=4.0, 1.4 Hz, H-40), 6.32 (bs, 1H, NH).
LSIMSHRMS, m/z; calcd for
(M+Na)+
C26H35NO5SNa: 453.2133. Found: 496.2121.
1
cmꢀ1 (NH); H NMR (CDCl3): d 1.40, 1.41 (2Âd, 6H,
4.4. General procedure for clavams formation
J=6.8 Hz, isopr.), 2.93 (ddd, 1H, J=15.1, 1.6, 0.8 Hz,
H-10a), 3.12 (ddd, 1H, J=15.1, 3.8, 2.5 Hz, H-10b), 3.31
(sept, 1H, J=7.0 Hz, isopr.), 4.25 (dd, 1H, J=11.3, 4.1
Hz, H-2a), 4.33 (dd, 1H, J=11.3, 7.9 Hz, H-2b), 4.80
(dd, 1H, J=7.9, 4.1 Hz, H-1), 5.17 (dd, 1H, J=3.8, 1.6
Hz, H-40), 5.85 (bs, 1H, NH), 7.33–7.44 (m, 5H, aryl);
13C NMR (CDCl3) d: 16.47, 16.63, 45.99, 52.54, 71.50,
78.30, 79.05, 126.98, 129.06, 129.35, 136.24, 165.76; UV
e (lmax): 8800 (205), 4940 (214sh); CD Áe (lmax): +10.9
(187.0), ꢀ7.0 (217.0); ESIHRMS, m/z; (M+Na)+ calcd
for C14H19NO5SNa: 336.0876. Found: 336.0884.
To a solution of 4-alkoxyazetidinone 22–29 and 42–49
(0.21 mmol) in acetonitrile (5 mL) were added the tet-
rabutylammonium bromide (0.07 g, 0.21 mmol) and
potassium carbonate (0.31 g, 3.15 mmol). The mixture
was heated under reflux for 1 h, cooled, diluted with
toluene (5 mL) and filtered. The colorless solution was
washed with water (5 mL), dried with magnesium sul-
fate, filtered and concentrated to dryness. The residue
was purified on a silica gel using hexane–ethyl acetate
7:3 (v/v) as an eluent, to give corresponding clavams.
4.3.4. (1R,40S) 1-O-(Azetidin-20-on-40-yl)-2-O-(100,100-di-
methyl-200-phenyl-ethanesulfonyl)-1-phenyl-1,2-ethanediol
(26). Rf (hexane–ethyl acetate v/v 3:7) 0.6; [a]D ꢀ63.1 (c
0.6, CH2Cl2); IR (film): 1342 cmꢀ1 (S¼O), 1774 cmꢀ1
4.4.1. (3R,5R) 3-Phenyl-clavam (30). Mp 49.5-51.0 ꢁC;
Rf (hexane–ethyl acetate v/v 7:1) 0.6; [a]D +106.4 (c 1.9,
CH2Cl2); IR (film): 1783 cmꢀ1 (C¼O); 1H NMR
(CDCl3): d 2.83 (ddd, 1H, J=11.9, 8.2, 0.9 Hz, H-2a),
2.99 (dd, 1H, J=16.5, 0.9 Hz, H-6a), 3.40 (ddd, 1H,
J=16.5, 2.9, 0.9 Hz, H-6b), 4.24 (ddd, 1H, J=11.9, 6.2,
0.5 Hz, H-2b), 5.18 (dd, 1H, J=8.2, 6.2 Hz, H-3), 5.57
(d, 1H, J=2.9 Hz, H-5), 7.33–7.41 (m, 5H, aryl); 13C
NMR (CDCl3): d 46.03, 53.23, 82.40, 85.12, 125.95,
128.43, 128.74, 138.35, 177.71; UV e (lmax): 14900
(208sh), 12800 (214sh), 970 (234sh); CD Áe (lmax): ꢀ24.0
(197.0), ꢀ9.4 (213.5), +20.1 (228.5sh), +23.7 (236.5);
ESIHRMS, m/z; (M+Na)+ calcd for C11H11NO2SNa:
212.0682. Found: 212.0691.
1
(C¼O), 3340 cmꢀ1 (NH); H NMR (CDCl3): d 1.35 (s,
6H, 2ÂCH3), 2.91 (ddd, 1H, J 1=5.1, 1.6, 0.8 Hz, H-
30a), 3.08 (ddd, 1H, J=15.1, 4.0, 2.5 Hz, H-30b), 3.10 (s,
2H, 1H, CH2Ph), 4.30 (dd, 1H, J=11.4, 8.0 Hz, H-2a),
4.37 (dd, 1H, J=11.4, 4.2 Hz, H-2b), 4.82 (dd, 1H,
J=8.0, 4.2 Hz, H-1), 5.13 (dd, 1H, J=4.0, 1.6 Hz, H-
40), 6.81 (bs, 1H, NH), 7.02–7.56 (m, 10H, 2Âaryl); 13C
NMR (CDCl3): d 21.05, 21.09, 41.27, 45.88, 63.59,
72.02, 77.87, 79.37, 126.71, 127.24, 128.28, 128.98,
129.13, 130.96, 134.52, 136.08, 166.20; UV e (lmax):
18300 (207), 10800 (215sh); CD Áe (lmax):ꢀ15.9 (189.4),
+5.7 (220.0); ESIHRMS, m/z; (M+Na)+ calcd for
C21H25NO5SNa: 426.1346. Found: 426.1366.
4.4.2. (3R,5S) 3-Phenyl-clavam (31). Rf (hexane–ethyl
acetate v/v 7:6) 0.4; [a]D ꢀ259.8 (c 0.7, CH2Cl2); IR
1
(film): 1784 cmꢀ1 (C¼O); H NMR (CDCl3): d 3.04 (d,
4.3.5. (1R,40R) 1-O-(Azetidin-20-on-40-yl)-2-O-(100,100-di-
methyl-200-phenyl-ethanesulfonyl)-1-phenyl-1,2-ethanediol
(27). Rf (hexane–ethyl acetate v/v 3:7) 0.55; [a]D ꢀ42.1
(c 0.4, CH2Cl2); IR (film): 1342 cmꢀ1 (S¼O), 1774 cmꢀ1
1H, J=16.1 Hz, H-6a), 3.35 (ddd, 1H, J=16.1, 2.6, 0.9
Hz, H-6b), 3.46 (ddd, 1H, J=10.6, 7.1, 0.9 Hz, H-2a),
3.62 (dd, 1H, J=10.6, 7.6 Hz, H-2b), 5.27 (dd, 1H,
J=7.1, 7.6 Hz, H-3), 5.32 (dd, 1H, J=2.9, 0.5 Hz, H-5),
7.31–7.40 (m, 5H, aryl); 13C NMR (400 MHz, CDCl3): d
43.75, 53.82, 84.92, 85.34, 126.08, 128.62, 128.74,
138.31, 177.45; UV e (lmax): 8800 (209sh), 7300 (215sh),
440 (237sh); CD Áe (lmax): +40.9 (189.0), +8.0 (200.5),
ꢀ12.5 (224.0), ꢀ13.7 (233.0); ESIHRMS, m/z;
(M+Na)+ calcd for C11H11NO2SNa: 212.0682. Found:
212.0688.
1
(C¼O), 3343 cmꢀ (NH); H NMR (CDCl3): d 1.33 (s,
6H, 2ÂCH3), 2.95 (ddd, 1H, J=15.1, 1.6, 0.8 Hz, H-
40a), 3.09 (s, 2H, CH2Ph), 3.13 (ddd, 1H, J=15.1, 3.8,
2.5 Hz, H-40b), 4.31 (dd, 1H, J=11.3, 4.3 Hz, H-2a),
4.39 (dd, 1H, J=11.3, 7.9 Hz, H-2b), 4.83 (dd, 1H,
J0=7.9, 4.3 Hz, H-1), 5.20 (dd, 1H, J=3.8, 1.6 Hz, H-
4 ), 5.82 (bs, 1H, NH), 7.10–7.45 (m, 10H, 2Âaryl); 13C
NMR (CDCl3): d 21.08, 21.10, 41.33, 45.99, 63.50,
71.63, 78.31, 79.00, 127.02, 127.23, 128.27, 129.06,
129.34, 130.94, 134.63, 136.40, 165.72; ESIHRMS, m/z;
(M+Na)+ calcd for C21H25NO5SNa: 426.1346. Found:
426.1367.
4.4.3. (3S,5R) 3-Phenyl-clavam (32). [a]D +256,5 (c 3.6,
CH2Cl2); UV e (lmax): 9760 (208sh), 7900 (215sh), 490
(236sh); CD Áe (lmax): ꢀ47.8 (189.0), ꢀ11.7 (198.5),
+16.4 (220.5), +15.8 (233.0).
4.3.6. (1S,40R) and (1S,40S) 1-O-(Azetidin-20-on-40-yl)-2-
O-(2,4,6-triisopropylbenzenesulfonyl)-1-phenyl-1,2-etha-
nediol (28 and 29). Yield: 43%; Rf (hexane–ethyl acetate
v/v 7:3) 0.2; IR (film): 1776 cmꢀ1 (C¼O), 3269 cmꢀ1
4.4.4. (3S,5S) 3-Phenyl-clavam (33). [a]D ꢀ104.8 (c 1.6,
CH2Cl2); UV e (lmax): 12100 (208sh), 10300 (215sh), 750
(236sh); CD Áe (lmax): +30.9 (193.5), +8.6 (213.0),
ꢀ14.5 (225.0sh), ꢀ21.4 (236.5). Anal. calcd for
C11H11NO2S taken for the mixture of 32 and 33: C,
69.83; H, 5.86; N, 7.40. Found: C, 69.32; H, 5.80; N,
7.23.
1
(NH); H NMR (CDCl3) selected signals taken for the
mixture of 28 and 29; 29: d 2.85 (ddd, 1H, J=15.1, 1.5,
0.8 Hz, H-30a), 3.06 (ddd, 1H, J=15.1, 4.0, 2.6 Hz, H-
30b), 4.81 (dd, 1H, J=3.7, 8.4 Hz, H-1), 5.10 (dd, 1H,
J=4.0, 1.5 Hz, H-40), 5.64 (bs, 1H, NH); 28: 2.82 (ddd,
1H, J=15.1, 1.5, 0.7 Hz, H-30a), 3.00 (ddd, 1H, J=15.1,
4.0, 2.7 Hz, H-30b), 4.83 (dd, 1H, J=3.8, 8.1 Hz, H-1),
4.4.5. (1R) 1-Phenyl-2-O-triphenylmethyl-1,2-ethanediol
(34R). To a solution of 14R (0.52 g, 3.76 mmol) in a
dry CH2Cl2 (10 mL) the TrCl (1.15 g, 4.14 mmol) was

412
M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
added. The reaction was stirred for 3 h, diluted with
water and extracted ethyl ether. The combined organic
layers were dried with magnesium sulfate, filtered and
concentrated to dryness. The residue was purified by a
column chromatography on silica gel using hexane–
ethyl acetate 9:1 (v/v) as eluent, to give 34R (1.24 g,
87%). Yield: 87%; Rf (hexane–ethyl acetate v/v 7:3)
0.65; [a]D ꢀ10.9 (c 0.7, CH2Cl2); IR (film): 3445 cmꢀ1
sium sulfate, filtered and concentrated. The residue was
purified by a column chromatography on silica gel using
hexane–ethyl acetate 7:3 (v/v) as eluent, to give 36R
(0.496 g, 96%); Rf (hexane–ethyl acetate v/v 3:1) 0.35;
[a]D ꢀ102.5 (c 1.3, CH2Cl2); IR (film): 3436 cmꢀ1 (OH);
1H NMR (CDCl3): d 3.63 (dd, 1H, J=11.7, 3.7 Hz, H-
2a), 3.71 (dd, 1H, J=11.7, 8.5 Hz, H-2b), 3.86 (m, 1H,
Allyl), 4.04 (m, 1H, Allyl), 4.45 (dd, 1H, J=6.9, 5.0 Hz,
H-1), 5.16 (dm, 1H, Allyl), 5.29 (m, 1H, Allyl), 5.92
(dddd, 1H, J=17.2, 10.4, 6.2, 5.3 Hz, Allyl),7.28–7.40
(m, 5H, aryl); 13C NMR (CDCl3): d 67.34, 69.75, 82.13,
117.19, 126.86, 128.12, 128.52, 134.46, 138.46;
ESIHRMS, m/z; (M+Na)+ calcd for C11H14O2Na:
201.0910. Found: 201.0897. Anal. calcd for C11H14O2:
C, 74.13; H, 7.92. Found: C, 73.91; H, 7.83.
1
(OH); H NMR (CDCl3): d 3.28 (dd, 1H, J=9.7, 8.3
Hz, H-2a), 3.35 (dd, 1H, J=9.7, 3.7 Hz, H-2b), 4.76
(dd, 1H, J=8.3, 3.7 Hz, H-1), 7.21–7.33 (m, 14H aryl),
7.39–7.44 (m, 6H, aryl); 13C NMR (CDCl3): d 69.28,
73.30, 87.07, 126.21, 127.14, 127.72, 127.88, 128.24,
128.63, 140.47, 143.74; ESIHRMS, m/z; (M+Na)+
calcd for C27H24O2Na: 403.1669. Found: 403.1692.
Anal. calcd for C27H24O2: C, 85.23; H, 6.36. Found: C,
85.30; H, 6.26.
4.4.10. (1S) 1-O-Allyl-1-phenyl-1,2-ethanediol (36S).
[a]D +95.5 (c 1.3, CH2Cl2). Anal. calcd for C11H14O2:
C, 74.13; H, 7.92. Found: C, 73.62; H, 8.06.
4.4.6. (1S) 1-Phenyl-2-O-triphenylmethyl-1,2-ethanediol
(34S). [a]D +11.5 (c 1.4, CH2Cl2). Anal. calcd for
C27H24O2: C, 85.23; H, 6.36. Found: C, 84.95; H, 6.38.
4.4.11. (1R) 1-Phenyl-1-O-(Z-prop-10-en-10-yl)-1,2-etha-
nediol (37R). A solution of allyl ether 36R (0.44 g, 2.47
mmol) and freshly sublimed t-BuOK (0.69 g, 6.18
mmol) in DMSO (30 mL), was stirred at 55 ꢁC for 1.5 h.
The reaction mixture was diluted with a satd aq NaCl
(30 mL). The solution was extracted with t-butyl-methyl
ether (3Â). The combined organic extracts were dried
with magnesium sulfate, filtered and concentrated to
dryness. The residue was purified by a column chroma-
tography on silica gel using hexane–ethyl acetate 17:3
(v/v) as eluent, to give 37R (0.392 g, 89%); Rf (hexane–
ethyl acetate v/v 3:1) 0.40; mp 65–66.5 ꢁC; [a]D +92.1 (c
0.7, CH2Cl2); IR (film): 1665 cmꢀ1 (C¼C), 3239 cmꢀ1
4.4.7. (1R) 1-O-Allyl-1-phenyl-2-O-triphenylmethyl-1,2-
ethanediol (35R). To a cold solution (at 0 ꢁC) of 34R
(1.20 g, 3.16 mmol) in dry DMF (20 mL) the NaH sus-
pension in mineral oil (60%; 0.15 g, 3.79 mmol) was
added. The solution was stirred at 0 ꢁC for 0.5 h and
allyl bromide (0.35 g, 3.79 mmol) was added dropwise.
Cooling bath was removed and reaction mixture was
stirred for 2 h (TLC monitoring) at room temperature.
The excess of NaH was decomposed with MeOH (1
mL). The reaction mixture was diluted with sat. aq
NaCl (50 mL). The solution was extracted with t-butyl-
methyl ether (3Â). The combined organic extracts were
dried with magnesium sulfate, filtered and concentrated
to dryness. The residue was purified by a column chro-
matography on silica gel using hexane–ethyl acetate 5:1
(v/v) as eluent to obtain 35R (1.27 g, 96%); Rf (hexane–
ethyl acetate v/v 3:1) 0.75; mp 82–84 ꢁC; [a]D ꢀ11.0 (c
1
(OH); H NMR (CDCl3): d 1.67 (dd, 1H, J=8.0, 4.0
Hz, H-1), 3.76 (m, 2H, H-2), 4.46 (dq, 1H, J=6.2, 6.8
Hz, H-20), 4.75 (dd, 1H, J=6.8, 1.7 Hz, CH3), 5.95 (dq,
1H, J=6.2, 1.7 Hz, H-10), 7.28–7.43 (m, 5H, aryl); 13C
NMR (CDCl3): d 9.40, 67.19, 84.11, 102.63, 126.54,
128.23, 128.54, 138.12, 144.16; ESIHRMS, m/z;
(M+Na)+ calcd for C11H14O2Na: 201.0886. Found:
201.0894. Anal. calcd for C11H14O2: C, 74.13; H, 7.92.
Found: C, 74.11; H, 7.91.
1
1.1, CH2Cl2); IR (film): absence of hydroxyl group; H
NMR (CDCl3): d 3.17 (dd, 1H, J=9.6, 5.0 Hz, H-2a),
3.44 (dd, J=6.9, 9.6 Hz, H-2b), 3.90 (m, 1H, Allyl), 4.02
(m, 1H, Allyl), 4.45 (dd, 1H, J=6.9, 5.0 Hz, H-1), 5.16
(dm, 1H, Allyl), 5.29 (dm, 1H, Allyl), 5.92 (dddd, 1H,
Allyl), 7.11–7.49 (m, 20H, Ph+Tr); 13C NMR (CDCl3):
d 68.47, 69.91, 80.63, 86.68, 116.52, 126.84, 127.16,
127.69, 128.20, 128.74, 134.98, 140.04, 144.05;
ESIHRMS, m/z; (M+Na)+ calcd for C30H28O2Na:
443.1982. Found: 443.2003. Anal. calcd for C30H28O2:
C, 85.68; H, 6.71. Found: C, 85.72; H, 6.75.
4.4.12. (1S) 1-Phenyl-1-O-(Z-prop-10-en-10-yl)-1,2-etha-
nediol (37S). [a]D ꢀ81.3 (c 0.8, CH2Cl2).
4.4.13. (1S) 2-O-Methanesulfonyl-1-O-(Z-prop-10-en-10-
yl)-1-phenyl-1,2-ethanediol (38S). Yield: 96%; Rf (hex-
ane–ethyl acetate v/v 3:1) 0.4; [a]D ꢀ15.5 (c 0.9,
CH2Cl2); IR (film): 1350 cmꢀ1 (S¼O), 1668 cmꢀ1
1
(C=C); H NMR (CDCl3): d 1.65 (dd, 3H, J=6.9, 1.8
4.4.8. (1S) 1-O-Allyl-1-phenyl-2-O-triphenylmethyl-1,2-
ethanediol (35S). [a]D +11.3 (c 0.7, CH2Cl2). Anal.
calcd for C30H28O2: C, 85.68; H, 6.71. Found: C, 85.68;
H, 6.61.
Hz, CH3), 3.01 (s, 3H, Ms), 4.34 (dd, 1H, J=11.3, 3.7
Hz, H-2a), 4.45 (dd, 1H, J=11.3, 8.0 Hz, H-2), 4.48 (dq,
1H, J=6.2, 6.9 Hz, H-20), 4.92 (dd, 1H, J=8.0, 3.7 Hz, H-
1), 5.93 (dq, 1H, J=6.2, 1.9 Hz, H-10), 7.28–7.46 (m, 5H,
aryl); 13C NMR (CDCl3): d 9.40, 37.70, 72.37, 80.82,
103.21, 126.67, 128.90, 128.92, 136.39, 143.69; ESIHRMS,
m/z; (M+Na)+ calcd for C12H16O4SNa: 279.0662.
Found: 279.0654. Anal. calcd for C12H16O4S: C, 56.23; H,
6.29; S 12.51. Found: C, 56.35; H, 6.18; S 12.39.
4.4.9. (1R) 1-O-Allyl-1-phenyl-1,2-ethanediol (36R).
Compound 35R (1.22 g, 2.90 mmol) was dissolved in a
methanolic solution of p-TsOH (5%; 60 mL). The reac-
tion was complete after 1 h (TLC monitoring). The
reaction mixture was concentrated, diluted with water
(50 mL) and extracted with t-butyl-methyl ether (3Â).
The combined organic extracts were dried with magne-
4.4.14. (1R) 2-O-Isopropanesulfonyl-1-phenyl-1-O-(Z-
prop-10-en-10-yl)-1,2-ethanediol (39R). Yield: 94%; Rf

M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
413
(hexane–ethyl acetate v/v 3:1) 0.5; [a]D +12.2 (c 0.9,
CH2Cl2); IR (film): 1670 cmꢀ1 (C¼C); 1H NMR
(CDCl3): d 1.41, 1.42 (2Âd, 3H, J=6.8 Hz, isopr.), 1.65
(dd, 3H, J=6.9, 1.8 Hz, CH3), 3.33 (sept, 1H, J=6.8
Hz, isopr.), 4.32 (dd, 1H, J=11.1, 3.7 Hz, H-2a), 4.39
(dd, 1H, J=11.1, 8.0 Hz, H-2b), 4.46 (dq, 1H, J=6.2,
6.9 Hz, H-20), 4.92 (dd, 1H, J=8.0, 3.7 Hz, H-1), 3.93
(dq, 1H, J=6.2, 1.8 Hz, H-10), 7.31–7.41 (m, 5H, aryl);
13C NMR (CDCl3): d 9.34, 16.45, 16.59, 52.44, 71.63,
80.89, 102.91, 126.66, 128.75, 128.78, 136.59, 143.77;
ESIHRMS, m/z; (M+Na)+ calcd for C14H20O4SNa:
307.0975. Found: 307.0992. Anal. calcd for C14H20O4S:
C, 59.13; H, 7.09; S, 11.28. Found: C, 59.25; H, 6.99; S,
11.06.
52.49, 71.39, 80.28, 80.93, 126.99, 128.97, 129.28,
136.37, 170.41; UV e (lmax): 4850 (207sh), 2800 (215sh);
CD Áe (lmax): +13.0 (189.8), ꢀ5.7 (217.8); MS (ESI),
m/z; (M+Na)+ calcd for C15H21NO5SNa: 350.1033.
Found: 350.1. Anal. calcd for C15H21NO5S: C, 55.03;
H, 6.47; N, 4.28; S, 9.79. Found: C, 54.97; H, 6.37; N,
4.18; S, 9.61.
4.4.18. (1R,30R,40S) 2-O-Isopropanesulfonyl-1-O-(30-
methyl-azetidin-20-on-40-yl)-1-phenyl-1,2-ethanediol (43).
Rf (hexane–ethyl acetate v/v 1:1) 0.35; [a]D ꢀ78.5 (c
0.5, CH2Cl2); IR (film): 1347 cmꢀ1 (S¼O), 1771 cmꢀ1
1
(C¼O), 3341 cmꢀ1 (NH); H NMR (CDCl3): d 1.26 (d,
3H, J=7.7 Hz, CH3), 1.41, 1.42 (2Âd, 6H, J=6.8 Hz,
isopr.), 3.28 (ddq, 1H, J=2.2, 4.4, 7.7 Hz, H-30), 3.33
(sept, 1H, J=6.8 Hz, isopr), 4.28 (dd, 1H, J=11.4, 7.5
Hz, H-2a), 4.32 (dd, 1H, J=11.4, 4.4 Hz, H-2b), 4.82
(dd, 1H, J=7.5, 4.4 Hz, H-30), 4.98 (d, 1H, J=4.4 Hz,
H-40), 6.78 (bs, 1H, NH), 7.28–7.46 (m, 5H, aryl); 13C
NMR (CDCl3): d 8.67, 16.54, 16.61, 50.39, 52.72, 72.11,
79.47, 80.19, 126.65, 128.84, 128.97, 136.00, 171.10; UV
e (lmax): 4500 (207sh), 2400 (216sh); CD Áe (lmax):
ꢀ11.0 (190.2), +5.3 (220.0); ESIHRMS, m/z;
(M+Na)+ calcd for C15H21NO5SNa: 350.1033. Found:
350.1050. Anal. calcd for C15H21NO5S: C, 55.03; H,
6.47; N, 4.28; S, 9.79. Found: C, 54.93; H, 6.47; N, 4.20;
S, 9.87.
4.4.15.
(1S) 1-Phenyl-1-O-(Z-prop-10-en-10-yl)-2-O-
(2,4,6-triisopropyl-benzenesulfonyl)-1,2-ethanediol (41S).
Yield: 86%; Rf (hexane–ethyl acetate v/v 3:1) 0.35; mp
57.5–58.5 ꢁC; [a]D ꢀ11.5 (c 1.1, CH2Cl2); IR (film): 1671
1
cmꢀ1 (C¼O); H NMR (CDCl3): d 1.25 (d, 6H, J=6.8
Hz, TIBS), 1.27 (d, 12H, J=7.0 Hz, TIBS), 1.59 (dd,
3H, J=6.8, 1.7 Hz, CH3), 2.92 (sept, 1H, J=.8 Hz,
TIBS), 4.16 (sept, 2H, J=7.0 Hz, TIBS), 4.21 (dd, 1H,
J=11.9, 5.5 Hz, H-2a), 4.23 (dd, 1H, J=11.9, 6.4 Hz,
2a), 4.41 (dq, 1H, J=6.2, 6.8 Hz, H-20), 4.92 (dd, 1H,
J=6.4, 5.5 Hz, H-1), 5.85 (dq, 1H, J=6.2, 1.7 Hz, H-
10), 7.23-7.45 (m, 7H, aryl); 13C NMR (CDCl3): d 9.33,
23.51, 24.65, 24.69, 29.63, 34.22, 71.50, 80.82, 102.87,
123.73, 126.63, 128.68, 129.48, 136.95, 143.76, 150.79,
153.70; ESIHRMS, m/z; (M+Na)+ calcd for
C26H36O4SNa: 467.2227. Found: 467.2241. Anal. calcd
for C26H36O4S: C, 70.23; H, 8.16; N, 7.21. Found: C,
70.16; H, 8.05; N, 7.10.
4.4.19. (1R,30S,40R) 2-O-(100,100-Dimethyl-200-phenyl-etha-
nesulfonyl)-1-O-(30-methyl-azetidin-20-on-40-yl)-1-phenyl-
1,2-ethanediol (44). Rf (hexane–ethyl acetate v/v 1:1) 0.3;
[a]D ꢀ22.6 (c 0.7, CH2Cl2); IR (film): 1343 cmꢀ1 (S¼O),
1771 cmꢀ1 (C¼O), 3340 cmꢀ1 (NH); 1H NMR (CDCl3):
d 1.32 (s, 6H, 2ÂCH3), 1.35 (d, 3H, J=7.5, Hz, CH3),
3.08 (s, 2H, CH2Ph), 3.35 (ddq, 1H, J=4.2, 2.0, 7.5 Hz,
H-30), 4.32 (dd, 1H, J=11.1, 4.3 Hz, H-2a), 4.42 (dd,
1H, J=11.1, 7.9 Hz, H-2b), 4.78 (dd, 1H, J=7.9, 4.3
Hz, H-1), 5.11 (d, 1H, J=4.2 Hz, H-40), 5.75 (bs, 1H,
NH), 7.10–7.19 (m, 2H, aryl), 7.27–7.44 (m, 8H, aryl);
13C NMR (CDCl3): d 8.63, 21.03, 41.26, 51.14, 63.39,
71.41, 80.44, 80.98, 127.11, 127.21, 128.26, 129.03,
129.35, 130.92, 134.60, 136.55, 170.46; UV e (lmax):
17300 (207), 9000 (216sh); CD Áe (lmax): +10.0 (189.5),
ꢀ3.5 (220.5); ESIHRMS, m/z; (M+Na)+ calcd for
C22H27NO5SNa: 440.1502. Found: 440.1510.
4.4.16. (1R) 2-O-(100,100-Dimethyl-200-phenyl-ethanesulfo-
nyl)-1-phenyl-1-O-(Z-prop-10 -en-10 -yl)-1,2-ethanediol
(40R). Yield: 58%; Rf (hexane–ethyl acetate v/v 3:1)
0.65; [a]D ꢀ4.1 (c 0.8, CH2Cl2); IR (film): 1345 cmꢀ1
1
(S¼O), 1669 cmꢀ1 (C¼O); H NMR (CDCl3): d 1.33 (s,
6H, 2ÂCH3), 1.66 (dd, 3H, J=6.8, 1.7 Hz, CH3), 3.11
(s, 2H, CH2Ph), 4.41 (m, 2H, H-2a, 2b), 4.51 (dq, 1H,
J=6.2, 6.8 Hz, H-10), 4.95 (dd, 1H, J=6.5, 5.2 Hz, H-
1), 5.96 (dq, 1H, J=6.2, 1.7 Hz, H-20), 7.11–7.21 (m,
2H, aryl), 7.27–7.43 (m, 8H, aryl); 13C NMR (CDCl3): d
9.40, 20.93, 20.95, 41.18, 63.38, 71.40, 80.91, 102.87,
126.71, 127.11, 128.19, 128.73, 128.77, 130.98, 134.84,
136.73, 143.92; ESIHRMS, m/z; (M+Na)+ calcd for
C21H26O4SNa: 397.1444. Found: 397.1462. Anal. calcd
for C21H26O4S: C, 67.39; H, 7.00; S 8.56. Found: C,
67.37; H, 7.21; S 8.63.
4.4.20. (1R,30R,40S) 2-O-(100,100-Dimethyl-200-phenyl-etha-
nesulfonyl)-1-O-(30-methyl-azetidin-20-on-40-yl)-1-phenyl-
1,2-ethanediol (45). Rf (hexane–ethyl acetate v/v 1:1)
0.35; [a]D ꢀ40.9 (c 0.6, CH2Cl2); IR (film): 1331 cmꢀ1
1
(S¼O), 1771 cmꢀ1 (C¼O), 3336 cmꢀ1 (NH); H NMR
4.4.17. (1R,30S,40R) 2-O-Isopropanesulfonyl-1-O-(30-
methyl-azetidin-20-on-40-yl)-1-phenyl-1,2-ethanediol (42).
Rf (hexane–ethyl acetate v/v 1:1) 0.30; mp 79.1–81 ꢁC;
[a]D ꢀ42.9 (c 0.5, CH2Cl2); IR (film): 1348 cmꢀ1 (S¼O),
1770 cmꢀ1 (C¼O), 3339 cmꢀ1 (NH); 1H NMR (CDCl3):
d 1.33 (d, 3H, J=7.5 Hz, CH3), 1.39, 1.40 (2Âd, 6H,
J=6.8 Hz, isopr.), 3.28 (sept, 1H, J=6.8 Hz, isopr.),
3.33 (ddq, 1H, J=3.7, 2.1, 7.5 Hz, H-30), 4.25 (dd, 1H,
J=11.2, 4.1 Hz, H-2a), 4.35 (dd, 1H, J=11.2, 8.0 Hz,
H-2b), 4.76 (dd, 1H, J=8.0, 4.1 Hz, H-1), 5.10 (d, 1H,
J=3.7 Hz, H-40), 5.78 (bs, 1H, NH), 7.30–7.49 (m, 5H,
aryl); 13C NMR (CDCl3): d 8.62, 16.53, 16.62, 51.13,
(CDCl3): d 1.29 (d, 3H, J=7.5 Hz, CH3), 1.35 (s, 6H,
2ÂCH3), 3.10 (s, 2H, CH2Ph), 3.31 (ddq, 1H, J=4.3,
2.0, 7.5 Hz, H-30), 4.30 (dd, 1H, J=11.3, 7.9 Hz, H-2a),
4.38 (dd, 1H, J=11.3, 4.1 Hz, H-2b), 4.82 (dd, 1H,
J=7.9, 4.1 Hz, H-1), 5.19 (d, 1H, J=4.3 Hz, H-40), 6.64
(bs, 1H, NH), 7.11-7.22 (m, 2H, aryl), 7.27-7.46 (m, 8H,
aryl); 13C NMR (CDCl3): d 10.99, 21.07, 21.10, 41.30,
53.59, 63.58, 71.87, 79.38, 84.93, 126.79, 127.23, 128.28,
129.00, 129.17, 130.95, 134.58, 136.30, 169.71; UV e
(lmax): 19400 (207), 11200 (215sh); CD Áe (lmax): ꢀ11.6
(192.5), +3.6 (220.5); ESIHRMS, m/z; (M+Na)+ calcd
for C22H27NO5SNa: 440.1502. Found: 440.1525.

414
M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
4.4.21.
(1S,30S,40R)
2-O-Methanesulfonyl-1-O-(30-
7.28–7.40 (m, 5H, aryl); 13C NMR (CDCl3): d 8.49,
23.50, 24.71, 24.69, 34.22, 51.17, 71.58, 80.26, 81.00,
123.82, 126.97, 128.98, 129.21, 136.76, 150.73, 153.91,
170.50; UV e (lmax): 64,040 (204), 11,900 (230sh); CD
Áe (lmax): ꢀ19.9 (188.6), +7.0 (216.2); ESIHRMS, m/z;
(M+Na)+ calcd for C27H37NO5SNa: 510.2285. Found:
510.2306.
methyl-azetidin-20-on-40-yl)-1-phenyl-1,2-ethanediol (46).
Rf (hexane–ethyl acetate v/v 3:7) 0.25; [a]D +71.1 (c
0.6, CH2Cl2); IR (film): 1353 cmꢀ1 (S¼O), 1769 cmꢀ1
(C¼O), 3354 cmꢀ1 (NH); H NMR (CDCl3): d 1.26 (d,
1
1H, J=7.6 Hz, CH3), 3.03 (s, 3H, Ms), 3.27 (ddq, 1H,
J=4.4, 2.2, 7.6 Hz, H-30), 4.32 (d, 2H, H-2a,2b), 4.80 (t,
1H, H-1), 5.03 (d, 1H, J=4.4 Hz, H-40), 6.87 (bs, 1H,
NH), 7.30–7.44 (m, 5H, aryl); 13C NMR (CDCl3): d
8.65, 37.87, 50.44, 72.46, 79.10, 80.08, 126.79, 126.99,
129.15, 135.94, 171.31; UV e (lmax): 8800 (206), 4900
(215sh); CD Áe (lmax): +13.5 (186.4), ꢀ5.4 (220.2);
ESIHRMS, m/z; (M+Na)+ calcd for C13H17NO5SNa:
322.0720. Found: 322.0739.
4.4.25. (3R,5R,6S) 6-Methyl-3-phenyl-clavam (50).
Yield: 62%; Rf (hexane–ethyl acetate v/v 3:7) 0.35; [a]D
1
+58.9 (c 0.9 CH2Cl2); IR (film): 1771 cmꢀ1 (C¼O); H
NMR (CDCl3): d 1.23 (d, 3H, J=7.7 Hz, CH3), 2.76
(ddd, 1H, J=12.0, 8.7, 0.5 Hz, H-2), 3.51 (dq, 1H,
J=3.3, 7.7 Hz, 1 Hz, H-6), 4.19 (ddd, 1H, J=12.0, 6.0,
0.5 Hz, H-20), 5.03 (dd, 1H, J=8.4, 6.0 Hz, H-3), 5.56
(bd, 1H, J=3.3 Hz, H-5), 7.27–7.44 (m, 5H, aryl); 13C
NMR (CDCl3): d 7.82, 49.69, 52.48, 83.13, 88.11,
125.99, 128.44, 128.72, 138.30, 182.53; UV e (lmax):
11,600 (208sh), 10,300 (215sh), 760 (238sh); CD Áe
(lmax): ꢀ27.8 (193.2), ꢀ9.6 (214.0), +10.4 (226.0sh),
+18.7 (240.2); ESIHRMS, m/z; (M+Na)+ calcd for
C12H13NO2Na: 226.0839. Found: 226.0849.
4.4.22.
(1S,30R,40S)
2-O-Methanesulfonyl-1-O-(30-
methyl-azetidin-20-on-40-yl)-1-phenyl-1,2-ethanediol (47).
Rf (hexane–ethyl acetate v/v 3:7) 0.20; [a]D +49.6 (c
0.8, CH2Cl2); IR (film): 1353 cmꢀ1 (S¼O), 1769 cmꢀ1
(C¼O), 3354 cmꢀ1 (NH); H NMR (CDCl3): d 1.39 (d,
1
1H, J=7.4 Hz, CH3), 3.00 (s, 3H, Ms), 3.36 (ddq, 1H,
J=4.3, 2.2, 7.4 Hz, H-30), 4.26 (dd, 1H, J=11.1, 3.8 Hz,
H-2a), 4.38 (dd, 1H, J=11.1, 8.1 Hz, H-2b), 4.75 (dd,
1H, J=8.1, 3.8 Hz, H-1), 5.10 (d, J=4.3 Hz, H-40), 5.68
(bs, 1H, NH), 7.35–7.49 (m, 5H, aryl); 13C NMR
(CDCl3): d 8.59, 37.59, 51.20, 71.82, 80.07, 80.95,
127.06, 129.12, 129.48, 136.27, 170.30; UV e (lmax):
8900 (205), 5000 (214sh); CD Áe (lmax): ꢀ9.4 (189.0),
+5.3 (219.2); ESIHRMS, m/z; (M+Na)+ calcd for
C13H17NO5SNa: 322.0720. Found: 322.0704.
4.4.26. (3R,5S,6R) 6-Methyl-3-phenyl-clavam (51).
Yield: 59%; Rf (hexane–ethyl acetate v/v 3:7) 0.25; [a]D
ꢀ236.2 (c 0.9, CH2Cl2); IR (film): 1779 cmꢀ1 (C¼O); 1H
NMR (C6D6): d 1.12 (d, 3H, J=7.6 Hz, CH3), 2.84
(ddd, 1H, J=10.5, 7.3, 0.7 Hz, H-20), 3.90 (ddq, 1H,
J=3.1, 0.7, 7.6 Hz, 1 Hz, H-6), 3.42 (dd, 1H, J=10.4,
8.0 Hz, H-2), 4.64 (bt, 1H, H-3), 4.68 (d, 1H, J=3.1 Hz,
H-5), 7.02–7.14 (m, 5H, aryl); 13C NMR (CDCl3): d
7.80, 47.77, 53.19, 84.93, 87.46, 126.25, 128.66, 128.79,
138.26, 182.39; UV e (lmax): 9500 (208sh), 8040 (220sh),
490 (236sh); CD Áe (lmax): +44.5 (189.4), +7.4 (201.0),
ꢀ11.2 (222.8), ꢀ14.6 (236.0); ESIHRMS, m/z;
(M+Na)+ calcd for C12H13NO2Na: 226.0839. Found:
226.0848.
4.4.23. (1S,30S,40R) 1-O-(30-Methyl-azetidin-20-on-40-yl)-
1-phenyl-2-O-(2,4,6-triisopropylbenzenesulfonyl) -1,2-
ethanediol (48). Rf (hexane–ethyl acetate v/v 1:1) 0.50;
mp 104–107 ꢁC; [a]D +46.1 (c 0.5, CH2Cl2); IR (film):
1347 cmꢀ1 (S¼O), 1774 cmꢀ1 (C¼O), 3271 cmꢀ1 (NH);
1H NMR (CDCl3): d 1.23 (d, 3H, J=7.7 Hz, CH3), 1.26
(d, 18H, J=6.8 Hz, TIBS), 2.91 (sept, 1H, J=6.8 Hz,
TIBS), 3.26 (ddq, 1H, J=4.4, 2.2, 7.7 Hz, H-30), 4.12
(sept, 2H, J=6.8 Hz, TIBS), 4.14 (dd, 1H, J=11.4, 8.1
Hz, H-2a), 4.20 (dd, 1H, J=11.4, 3.8 Hz, H-2b), 4.88
(dd, 1H, J=8.1, 3.8 Hz, H-1), 5.11 (d, 1H, J=4.4 Hz,
H-40), 6.40 (bs, 1H, NH), 7.19 (s, 2H, aryl TIBS), 7.27–
7.44 (m, 5H, aryl); 13C NMR (CDCl3): d 8.61, 23.49,
24.70, 29.72, 34.24, 50.52, 72.31, 79.98, 80.88, 123.90,
126.59, 126.91, 128.88, 129.29, 136.49, 150.77, 154.09,
170.74; UV e (lmax): 59750 (204), 11100 (230sh); CD Áe
(lmax): +6.4 (191.8), ꢀ4.5 (219.6); ESIHRMS, m/z;
(M+Na)+ calcd for C27H37NO5SNa: 510.2285. Found:
510.2276.
4.4.27. (3S,5R,6S) 6-Methyl-3-phenyl-clavam (52). [a]D
+244,3 (c 0.8, CH2Cl2). UV e (lmax): 9200 (209sh), 7700
(215sh), 450 (237sh); CD Áe (lmax): ꢀ43.9 (189.5), ꢀ6.8
(201.5), +13.8 (219.5), +14.9 (236.0). Anal. calcd
C12H13NO2S: C, 70.92; H, 6.45; N, 6.89. Found: C,
70.53; H, 6.56; N, 6.75.
4.4.28. (3S,5S,6R) 6-Methyl-3-phenyl-clavam (53).
Yield: 59%; [a]D ꢀ58.3 (c 0.7, CH2Cl2); UV e (lmax):
14500 (209sh), 11,600 (215sh), 880 (238sh); CD Áe (lmax):
+28.7 (193.0), +10.6 (213.0), ꢀ11.0 (226.4sh), ꢀ19.9
(240.2). Anal. calcd for C12H13NO2S: C, 70.92; H, 6.45;
N, 6.89. Found: C, 70.85; H, 6.50; N, 6.85.
4.4.24. (1S,30R,40S) 1-O-(30-Methyl-azetidin-20-on-40-yl)-
1-phenyl-2-O-(2,4,6-triisopropylbenzenesulfonyl) -1,2-
ethanediol (49). Rf (hexane–ethyl acetate v/v 1:1) 0.45;
mp 119–121 ꢁC; [a]D +31.5 (c 0.7, CH2Cl2); IR (film):
1347 cmꢀ1 (S¼O), 1774 cmꢀ1 (C¼O), 3257 cmꢀ1 (NH);
1H NMR (CDCl3): d 1.22, 1.24, 1.25 (3Âd, 18H, J=6.8
Hz, TIBS), 1.29 (d, 3H, J=6.7 Hz, CH3), 2.90 (sept, 1H,
J=6.8 Hz, TIBS), 3.32 (ddq, 1H, J=4.3, 2.2, 7.6 Hz, H-
30), 4.09 (dd, 1H, J=11.1, 3.8 Hz, H-2a), 4.11 (sept, 1H,
J=6.8 Hz, TIBS), 4.20 (dd, 1H, J=11.1, 8.1 Hz, H-2a),
4.79 (dd, 1H, J=8.1, 3.8 Hz, H-1), 5.09 (d, 1H, J=4.3
Hz, H-40), 5.68 (bs, 1H, NH), 7.17 (s, 2H, aryl TIBS),
4.5. Assay of DD-carboxypeptidase activity
The enzyme activity was measured as described pre-
viously.27,28 Samples for assay of the DD-carboxy-
peptidase activity consisted of 10 mL of DD-
carboxypeptidase from Saccharopolyspora erythraea
PZH TZ 64-575 (40 units/mg), 20 mL of substrate solu-
tion containing 4.52 mg/mL Na, Ne-diacetyl-l-lysyl-d-
alanyl-d-alanine in 0.1 M phosphate buffer, pH 8.0 and
10 mL of 0.1 M phosphate buffer, pH 8.0. Standard
sample contained 20 mL of d-alanine in distilled water.

M. Cierpucha et al. / Bioorg. Med. Chem. 12 (2004) 405–416
415
Reaction mixture for assay of the DD-carboxypeptidase
activity consisted of 60 mL of 0.05 mg/mL flavin adenine
dinucleotide in 0.1 M phosphate buffer, pH 8.0, 10 mL
of 0.05 mg/mL horseradish peroxidase (1230 units/mg)
in distilled water, 5 mL of 5 mg/mL o-dianisidine in
methanol, and 2 mL of 11.77 mg/mL d-amino acid
oxidase from porcine kidney (6.7 units/mg) in 0.1 M
phosphate buffer, pH 8.0.
6. Clauss, K.; Grimm, D.; Prossel, G. Liebigs Ann. Chem.
1974, 539.
7. De Bernardo, S.; Tengi, J. P.; Sasso, G. J.; Weigele, M. J.
Org. Chem. 1985, 50, 3457.
8. Muller, J. C.; Toome, V.; Pruess, D. L.; Blount, J. F.;
Weigele, M. J. Antibiot. 1983, 36, 217.
9. Hoppe, D.; Hilpert, T. Tetrahedron 1987, 43, 2467.
.
10. Ka•uza, Z.; Furman, B.; Krajewski, P.; Chmielewski, M.
Tetrahedron 2000, 56, 5553.
.
11. (a) Chmielewski, M.; Ka•uza, Z.; Furman, B. J. Chem.
Soc., Chem. Commun. 1996, 2689. (b) Furman, B.;
Samples were incubated for 30 min at 37 ꢁC and then
boiled for 2 min. After cooling, 77 mL of the reaction
mixture was added, and all samples were incubated for
10 min at 37 ꢁC. Next, to each sample was added 350 mL
of mixture consisting of methanol, distilled water and
sulfuric acid (5:5:6 by volume). Absorption of resulted
solution was measured at 540 nm.
.
Ka•uza, Z.; —ysek, R.; Chmielewski, M. Polish. J. Chem.
1999, 73, 43.
12. Borsuk, K.; Suwinska, K.; Chmielewski, M. Tetrahedron:
Asymmetry 2001, 12, 979.
13. Borsuk, K.; Kazimierski, A.; Solecka, J.; Urbanczyk-Lip-
kowska, Z.; Chmielewski, M. Carbohydr. Res. 2002, 337,
2005.
.
14. Ka•uza, Z.; Furman, B.; Chmielewski, M. Tetrahedron:
Asymmetry 1995, 6, 1719.
The inhibition of DD-peptidase 640-575 by the dis-
cussed above clavams was evaluated.31 Mixtures of 10
mL of DD-peptidase 64-575 (40 units/mg), 5 mL solution
of a clavam in methanol and 5 mL of 0.1 M phosphate
buffer, pH 8.0 were incubated for 45 min. at 37 ꢁC. The
concentration of a clavam in the mixture was from 0.1
to 0.000055 M. Following the incubation, 20 mL of sub-
strate solution was added to 20 mL of each sample and
resulted mixtures were incubated again. The inhibition
of DD-peptidase is given as ID50 (M).
.
15. Neuß, O.; Furman, B.; Ka•uza, Z.; Chmielewski, M. Het-
erocycles 1997, 45, 265.
16. Musicki, B.; Widlanski, T. S. J. Org. Chem. 1990, 55,
4231.
17. Watanabe, W. H.; Conlon, L. E. J. Am. Chem. Soc. 1957,
79, 2828.
18. Since cycloaddition to both enantiomeric forms of vinyl
ethers and (Z)-propenyl ethers derived from 14R and 14S
diols provides the same information on stereoselectivity of
the reaction, the representative procedures and full char-
acterization of ethers 18–21 and 38–41, and adducts
formed 22–29 and 42–49 were provided for one enantio-
The inhibition of penicillinase was evaluated following
literature method.29 The samples for the assay of inhi-
meric form only.
19. Furman, B.; Ka•uza, Z.; Chmielewski, M. J. Org. Chem.
1997, 62, 3135.
.
bition of b-lactamase consisted of 10 mm3 of penicilli-
6
nase (Penase, 5 10 IU/mL, Bacto), 20 mm3 0.1 M
.
phosphate buffer, pH 7.0, 10 mm3 solution of clavams
in methanol. The samples were incubated for 30 min at
37 ꢁC, then 30 mm3 of nitrocephin, 430 mm3 0.1 M
phosphate buffer pH 7.0 were added and all the samples
were incubated for 10 min at 37 ꢁC. Absorption was
measured at 482 nm. The inhibition of b-lactamase is
expressed as IC50 (M).
20. Prosser, T. J. J. Am. Chem. Soc. 1961, 83, 1701.
21. (a) Ogura, H.; Takayanagi, H.; Kerbo, K.; Furuhata, K.
J. Am. Chem. Soc. 1973, 95, 8056. (b) Rehling, H.; Jensen,
H. Tetrahedron Lett. 1972, 27, 2793. (c) Ong, E. C.;
Cusachs, L. C.; Weigang, O. E. J. Chem. Phys. 1982, 67,
3289. (d) Po•onski, T.; Milewska, M. Croat. Chim. Acta
1989, 62, 129.
22. (a) Anaya, J.; Gero, S. D.; Grande, M.; Hernando, J. I. M.;
Laso, N. M. Bioorg. Med. Chem. 1999, 7, 837. (b) Bar-
baro, G.; Battaglia, A.; Guerini, A.; Bertucci, C.; Ger-
emia, S. Tetrahedron Asym. 1998, 9, 3401.
The following clavams were tested for both activities:
30–33 and 50–53 (Table 2).
23. (a) Busson, R.; Roets, E.; Vanderhaeghe, H. In
Recent Advances in the Chemistry of ꢀ-lactam Anti-
biotics; Elks, J., Ed.; Chem. Soc: London, 1977;
p 304 (b) Boyd, D. B. J. Am. Chem. Soc. 1972, 94, 6513.
(c) Richardson, F. S.; Yeh, C.-Y.; Troxell, T. C.; Boyd,
D. B. Tetrahedron 1977, 33, 711. (d) Muller, J.-C.; Toome,
V.; Pruess, D. L.; Blount, J. F.; Weigele, M. J. Antibiot.
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