Synthesis and antimicrobial evaluation of farnesyl diphosphate mimetics

Article abstract of DOI:10.1016/S0045-2068(03)00025-7

The synthesis and first antimicrobial evaluation of farnesyl diphosphate mimetics are described. Several analogues (10, 12, 13, and 20) are inhibitors of Candida albicans, Shizosaccharomyces pombe, and Saccharomyces cerevisiae. The activities of analogues 10, 12, and 13, which contain a ω-phenyl moiety and a diphosphate isostere, are not attributable to inhibition of sterol biosynthesis via squalene synthase. Two geranyl phenylsulphones (14 and 15) are potent inhibitors of Escherichia coli. Analogue 15 exhibits potent activity towards Salmonella typhimurium and Pseudomonas aeruginosa (MIC - 2μg/mL) and represents the first type of semi-synthetic terpenoid allylic sulphone active against these bacteria.

Full text of DOI:10.1016/S0045-2068(03)00025-7

BIOORGANIC
CHEMISTRY
Bioorganic Chemistry 31 (2003) 80–97
www.elsevier.com/locate/bioorg
Synthesis and antimicrobial evaluation of
farnesyl diphosphate mimetics
a
c
Ian J.S. Fairlamb,a,b, Julia M. Dickinson, Rachael O’Connor,
*
Louis H. Cohen,d and Christa F. van Thield
a
Department of Chemistry and Materials, John Dalton Building, The Manchester
Metropolitan University, Chester Street, Manchester M20 5GD, UK
b
Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
c
Department of Biological Sciences, John Dalton Building, The Manchester Metropolitan University,
Chester Street, Manchester, M20 5GD, UK
Cholesterol Synthesis Research Unit, Department of Vascular and Connective Tissue Research,
d
TNO Prevention and Health, P.O. Box 2215, 2301 CE Leiden, Netherlands
Received 10 January 2002
Abstract
The synthesis and first antimicrobial evaluation of farnesyl diphosphate mimetics are de-
scribed. Several analogues (10, 12, 13, and 20) are inhibitors of Candida albicans, Shizosacchar-
omyces pombe, and Saccharomyces cerevisiae. The activities of analogues 10, 12, and 13, which
contain a x-phenyl moiety and a diphosphate isostere, are not attributable to inhibition of
sterol biosynthesis via squalene synthase. Two geranyl phenylsulphones (14 and 15) are potent
inhibitors of Escherichia coli. Analogue 15 exhibits potent activity towards Salmonella
typhimurium and Pseudomonas aeruginosa (MIC—2 lg/mL) and represents the first type
of semi-synthetic terpenoid allylic sulphone active against these bacteria.
Ó 2003 Elsevier Science (USA). All rights reserved.
Keywords: Squalene synthase; Farnesyl-protein transferase; Inhibitors; Antimicrobial agents; Copper(I)
catalysed tetrahydropyranyl ether displacements
* Corresponding author. Fax: +44-0-190-4432015.
E-mail address: ijsf1@york.ac.uk (I.J.S. Fairlamb).
0045-2068/03/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved.
doi:10.1016/S0045-2068(03)00025-7

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
81
1. Introduction
The synthesis and biological evaluation of farnesyl diphosphate (FDP) mimetics
has received notable attention, mainly as FDP is used as a substrate by both Squalene
synthase [1] (SQS) and farnesyl-protein transferase [2] (FPTase). SQS is a membrane-
bound enzyme located in the cholesterol biosynthetic pathway which catalyses the re-
ductive dimerisation of two molecules of FDP via presqualene diphosphate (2) to
squalene (3) (Scheme 1). Compounds that inhibit SQS reduce the formation of cho-
lesterol, a substance implicated in the development of Atherosclerosis [1]. FPTase cat-
alyses the farnesylation of the thiol group of cysteine located at the forth amino acid
(CAAX) position from the C-terminal of several small G-proteins. Amongst them is
the protein ras, which is involved in growth regulatory signal transduction [2]. Mu-
tated ras genes have been frequently found in various human malignancies and play
a role in human tumour growth. Hence, inhibition of FPTase is highly desirable, as
the oncogenic activity of mutated ras is dependant on the farnesylation by FPTase [3].
As part of an ongoing project into finding active antimicrobial agents, we were
particularly drawn to FDP mimetics, as they show diverse biological activity when
simple structural changes are made [3,4]. The antimicrobial activities of FDP mimet-
ics remains an area unexplored, even though potent agents that target sterol biosyn-
thesis or related biosynthetic pathways would be ideal targets that merit
investigation. FDP mimetics are synthetically easily accessible and therefore the con-
struction of a wide range of structurally diverse FDP mimetics are available for anti-
fungal evaluation.
From the extensive published works in this area we considered a farnesyl mimic and
diphosphate isostere essential for inhibitory activity [3]. Several hydrophobic mimics of
Scheme 1. FDP (1) is converted into squalene (3) by SQS and utilised by FPTase in the S-prenylation
process.

82
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
Fig. 1. Molecular ruler hypothesis for isoprenoid specificity.
the farnesyl chain are well precedented [3–5]. The X-ray co-crystal structure of FPTase
and FDP demonstrates the elongated orientation of the farnesyl chain within the en-
zyme active site [6]. A ‘‘molecular ruler’’ hypothesis for isoprenoid substrate specificity
has been proposed, where the depth of the hydrophobic binding cavity acts as a ruler in
discriminating between isoprenoids of different lengths [6] (Fig. 1).
We were particularly drawn to the farnesyl mimics fm-1 and fm-2, developed by
Wiemer [4a] and Distefano [5], respectively (Fig. 1). Based on the molecular ruler
hypothesis it was envisaged that the smaller farnesyl mimics, such as fm-3 or fm-4,
might be less specific towards SQS or FPTase. An ideal diphosphate isostere would
be one that shares electronic and steric similarities with the diphosphate moiety [7].
Such isosteres include bisphosphonic acids, mixed phosphonic/carboxyl acids, and
dicarboxyl acid moieties. We envisaged that an unusual isostere would be a sulpho-
nyl moiety (–SO2R), which may act as a less polar variant of diphosphate or as a
pro-drug, where on hydrolysis the sulphonic acid (a known phosphonate isostere)
is released.
2. Results and discussion
The synthetic routes to the fm-1 derivatives are shown in Scheme 2. Alcohol 4 was
synthesised in five steps from commercially available geraniol in 69% overall yield
using the method of Wiemer [4a]. The key step in this route was THPO-displacement
of 5 with PhMgBr under copper(I) iodide catalysis, proceeding in 82% yield.

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
83
Scheme 2. Synthetic Routes to fm-1 derivatives.
Bromination of 4 with NBS-DMS [8] or PBr3 affords 6, which is taken as crude
for reaction with benzenesulphinic acid sodium salt in DMF, providing the fm-1 sul-
phone target 7 in 81% overall yield from 4. PBr3 is the brominating reagent of choice
on scaling up the synthesis of 6. Alkylation of 6 using the anions of diethyl malonate
and triethyl phosphonoacetate was possible (generated in situ using NaH in THF) to
give 8 and 11 in 60% and 44% yields, respectively. Compound 8 was decarboxylated
under neutral conditions using NaCl in moist DMF, which proceeded in 63% yield.
Ester 9 was then hydrolysed using ethanolic NaOH at reflux to give acid 10 in 85%
yield. Selective hydrolysis of 11 using ethanolic NaOH at reflux gave acid 12 in 88%
yield. Conversion of 12–13 using TMSBr in collidine was somewhat cumbersome in
that hydrolysis with NaOH took over 22 days, affording 13 in 58% yield. The syn-
thesis of fm-2 derivatives was approached via two routes (Schemes 3 and 4).
E-Selective SeO2 oxidation of 14, followed by NaBH4 reduction, gave alcohol 15
in 80% yield (Note. We obtained 90% yield on 1.3 mmol scale) [9]. Alcohol 15 was
protected using 3,4-dihydro-2H-pyran (DHP) catalysed by TsOH, yielding the tetra-
hydropyranyl ether 16 in essentially quantitative yield (98%). The tetrahydropyranyl
ether (THPO–) generates a reactive centre allowing SN2 Grignard coupling using
RMgBr under CuI catalysed conditions [4a]. Tetrahydropyranyl ether 16 reacts with
PhMgBr (10 eqv) and CuI (5 eqv) to give 7 in 21% yield. Reducing the Grignard re-
agent to 5 equivalents, CuI to 1 equivalent and increasing the dilution (3-fold) gave 7
in 42% yield. The fm-2 target 17 was synthesised via standard benzoylation of 15
(57% yield).
The fm-2 alcohol 20 was synthesised according to the procedure of Distefano and
coworkers 19 [5] (Scheme 4). In short, compound 18 [9] was converted to 19 via este-
rification with benozyl chloride in 38% yield under standard conditions (Compound
19 is unstable). Selective hydrolysis of 19 using NH4OH in methanol proceeded to
give free alcohol 20 in 42% yield. It was also possible to synthesise 17 from 20, by
conversion to the light-sensitive bromide 21 using PBr3 or NBS-DMS, followed by
SN2 displacement using benzenesulphinic acid sodium salt in DMF to give 17 in
77% yield.

84
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
Scheme 3. Synthetic route A to fm-2 derivatives.
3. Biological results
The target and intermediate test compounds were passed through a general antim-
icrobial screen [10]. Three yeasts (Candida albicans, Shizosaccharomyces pombe, and
Saccharomyces cerevisiae, Table 1) and three bacteria (Bacillus subtilis, Escherichia
coli, and Staphylococcus aureus, Table 2) were chosen to evaluate the effectiveness
of the test compounds. All compounds were tested at a concentration of 200 lg/
mL in triplicate. The activities of compounds 4, 7–15, 17, 20, 23, 24, and the control
Squalestatin S1 [11] (Fig. 2) were screened against the yeasts shown in Table 1.
The test compounds exhibit quite diverse activities. Free alcohol 4 is a modest in-
hibitor of S. pombe and S. cerevisiae. Incorporation of a diphosphate bioisostere
results in enhanced activity. For example, compounds 10, 12, and 13 were all
active against the three yeasts. The free phosphonic acid 13 was, as expected, more
potent than the protected ester derivative 12. Free carboxylic acid 10 surprisingly
showed similar activity to the protected ester derivative 9. This is presumably due
to the presence of an esterase enzyme capable of hydrolysing 9 to the active acid
10 in vitro.
The control, squalestatin S1 [11], exhibited no activity towards any of the bacte-
ria. Therefore, S1 is either unable to cross the bacterial cell wall, or all of the bacteria
species screened are non-dependant on SQS and ultimately sterol biosynthesis [12].
Several of the compounds (4, 7, 10, 13, 14, 15, and 20) were active against Gram-pos-
itive B. subtilis, although only compounds 10 and 20 were inhibitors of S. aureus
(Gram-positive) (Table 2). Compound 10 was also a modest inhibitor of E. coli

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
85
Scheme 4. Synthetic route B to fm-2 derivatives.
Table 1
Activity of FDP mimetics against yeastsa
Compound
C. albicans
S. pombe
S. cerevisiae
4
7
na
9
8
11
11
14
17
7
11
10
12
19
20
9
8
11
na
13
11
10
19
13
7
9
10
11
12
13
14
15
17
20
23
24
S1b
11
18
15
14
10
15
5
16
20
12
16
nd
7
9
12
na
na
26
5
7
35
na
30
a Zone of inhibition (values are means of three experiments). Na, not active and nd, not determined.
b Control at 200 lg/mL.

86
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
Table 2
Activity of FDP mimetics against bacteriaa
Compound
B. subtilis
E. coli
S. aureus
4
7
10
7
na
na
na
na
14
na
15
42
na
8
na
na
na
na
30
na
na
na
na
6
8
na
na
25
15
7
9
10
13
14
15
17
20
S1b
12
na
15
na
na
na
a Zone of inhibition (values are means of three experiments). Na, not active.
b Control at 200 lg/mL.
Fig. 2. Squalestatin S1.
(Gram-negative) and is therefore non-selective towards Gram-positive or Gram-neg-
ative bacteria. Nevertheless, the activity of 10 is reliant on the presence of a free acid,
as ethyl ester 9 was inactive against all of the bacteria screened.
Both phenyl sulphones 14 and 15 are active against E. coli (Gram-negative). The
large zone of inhibition for 15 against E. coli is of notable attention (Fig. 3i). The
minimum inhibitory concentration (MIC) for 15 was determined to be 1.5 lg/mL
[13]. This result led to the additional screening of 15 (at varying concentrations)
i
ii
Fig. 3. (i) Inhibition zone of 15 (200 lg/mL) against E. coli. (ii) Inhibition zone of 15 (20 lg/mL) against S.
typhimurium.

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
87
Table 3
Inhibition zones of 15 against bacteriaa
Bacteria
Concentration (lg)
200
20
2
0.2
S. epidermidis
E. coli 8110
na
19
15
23
na
na
7
na
na
5
na
na
na
na
na
P. aeruginosa
S. typhimurium
Acinetobacter sp.
7
16
na
5
na
a Zone of inhibition (values are means of three experiments). Na, not active.
Fig. 4. Control FDP mimetic—TR011.
against several species of bacteria, including Staphylococcus epidermidis, E. coli 8110,
Pseudomonas aeruginosa, Salmonella typhimurium, and Acinetobacter sp. (Table 3).
Compound 15 is active against three of the five bacteria tested, with inhibition
observed for both P. aeruginosa and S. typhimurium at 2 lg/mL concentration.
The MIC for 15 against P. aeruginosa and S. typhimurium were determined to be
2 lg/mL.
However, for S. typhimurium at 20 lg/mL, it was apparent within the inhibition
zones that bacterial colonies had formed which were clearly not as sensitive to 15
compared to the others on the plate (Fig. 3ii). This seemingly resistant strain of re-
duced sensitivity to 15 is most likely to be a sub-type of S. typhimurium.
Preliminary efforts to determine the inhibition target(s) of the active compounds
were focused on SQS activity using an assay previously developed [14]. Unfortu-
nately we found that compounds 4, 10, 11, and 12 were not inhibitors of this enzyme
at 0.1 and 1 lM, respectively, whereas the controls Squalestatin S1 and TR011 [15]
(Fig. 4) caused >90% inhibition at both concentrations.
Compounds 7, 13, and 17 caused minor inhibition (ꢀ20%) of SQS at 1 and
0.1 lM. At higher concentrations the inhibitory activity of the phenylsulphone 17
was reduced, and we attribute that to low water solubility and associated micelle
formation.
4. Conclusions
In conclusion, we have constructed several FDP analogues, utilizing the synthetic
methodology described by Wiemer and coworkers [4] for the introduction of a

88
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
Fig. 5. The AGDP analogue described by Spielmann [16].
phenyl moiety at the x-terminus, that incorporate an appropriate isostere of the di-
phosphate moiety. The FDP analogues exhibit promising antimicrobial activities
and to the best of our knowledge are the first such results reported for any FDP an-
alogues. The activity of compounds 9–13 was thought to be attributable to inhibition
of SQS. However, the low SQS inhibition results suggest an alternative site of inhi-
bition, possibly FPTase, when compared directly with the antimicrobial results. Our
results correlate well with the 8-anilinogeranyl diphosphate (AGDP) analogue re-
cently reported by Spielmann and coworkers [16] (Fig. 5). AGDP is a poor SQS in-
hibitor ðIC50 ¼ 1000lMÞ and good FPTase inhibitor ðIC50 ¼ 0:5lMÞ. Selectivity is
an important objective when developing competitive FDP inhibitors as these com-
pounds may interfere with other FDP utilizing enzymes. Thus there is a clear possi-
bility that replacement of the terminal isoprene unit for a phenyl moiety increases the
selectivity of these FDP analogues toward FPTase.
Phenyl sulphone 15 was an unexpected inhibitor of the yeasts and bacteria species,
although its mode of inhibition may lie via inhibition of Farnesyl synthase (FSase),
the enzyme preceding SQS within the sterol biosynthetic pathway, for which com-
pound 15 shares closer electronic and structural similarity to geranyl diphosphate
ꢀ
_
(GDP)—the substrate for FSase. Recently Swiezewska [17] presented results
that show FSase is the main regulatory enzyme within ergosterol biosynthesis in
S. cerevisiae, responding to the greatest extent to changes in internal and external
environmental conditions when compared directly to SQS and 3-hydroxy-3-methyl-
glutaryl-coenzyme A (HMG-CoA) [18]. Inhibition of FSase may therefore represent
an attractive target for future sterol biosynthesis inhibitors.
The biological activities of the active antimicrobial compounds reported here,
against both FSase and FPTase, will be determined and reported in due course.
5. Experimental
5.1. Antimicrobial assay
The determination of the antimicrobial activity of each compound was assessed
using an established standard disc-plate method [10]. Sabourad’s agar (Oxoid Prod-
ucts) was prepared according to the manufacturers instructions, and then dispensed
in 20 mL amounts into glass universal bottles and these were autoclaved at 121 °C
and 15 psi for 15 min. The molten agar was poured into agar plates (Sterilin). Each
strain was inoculated into 10 mL of Sabourad’s broth (prepared according to

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
89
manufacturers instructions) and incubated at the appropriate temperatures (25 °C
for S. pombe and S. cerevisiae, 37 °C for C. albicans for 12 h). After incubation the
resultant broth culture was diluted in sterile saline to produce a 1/100 dilution. Asep-
tically, a 0.1 mL aliquot of this dilution was pipetted onto the agar plate and care-
fully spread around the agar surface. A sterile 4 mm paper disc was placed on the
centre of agar plate and then the test compound (20 ll of a 10, 1, 0.1, or 0.01 mg/
mL in absolute ethanol or water with final concentrations of 200, 20, 2, 0.2 lg/
mL, respectively) was inoculated onto the sterile paper disc. These plates were incu-
bated at the appropriate temperatures (25 °C for S. pombe and S. cerevisiae, 37 °C for
C. albicans for 24 h). To investigate the antimicrobial activity of the test compounds
on the bacterial species an identical procedure to the yeast assay was adopted, how-
ever, nutrient agar (LAB M) and nutrient broth (LAB M) were the preferred growth
media. Incubation of the bacterial species was conducted at 37 °C for 24 h.
5.2. In vitro SQS enzyme assay
The SQS screening was performed using an assay previously described [14]. Squa-
lestatin S1 [11] and TR011 [15] were used as controls in this assay. The controls
inhibited the enzyme by greater than 90% at both 0.1 and 1 lM.
5.3. General
Nuclear magnetic resonance (1H and 13C) spectra were recorded on a Jeol GNX
270 (at 270 and 67.8 MHz, respectively) spectrometer. Chemical shifts are reported in
parts per million (d) downfield from an internal tetramethylsilane reference. Cou-
pling constants (J values) are reported in hertz (Hz), and spin multiplicities are indi-
cated by the following symbols: s (singlet), d (doublet), t (triplet), q (quartet), m
(multiplet), and br (broad). The relative proportion of solvents in mixed chromato-
graphy solvents refer to the volume/volume ratio. Triethylamine, hexane, and dichlo-
romethane were dried over calcium hydride and distilled before use. All reaction
solvents were distilled for purity. Diethyl ether and THF were distilled from sodi-
um-benzophenone ketyl. Chloroform (400 mL) was washed with water (6 Â 200 mL)
(to remove ethanol), dried over MgSO4, and then distilled over P2O5 twice. All reac-
tions were performed in an inert atmosphere created by a slight positive pressure of
argon. GC spectra were recorded on a Finnigan 2000 series GC coupled to a Finn-
igan Trace MS, source Electron Impact (EI) 70 eV. GC Column: Restek Rtx-5MS
Crossbond 5% diphenyl-95% dimethyl polysiloxane (15 m, 0.25 mmID, 0.25 lmdf).
GC Conditions: 60–310 °C, Rate 10 °/min. GC internal standard—octadecane.
8-Phenyl-3,7-dimethyl-2E,6E-octadien-1-ol ð4Þ. To a stirred suspension of magne-
sium turnings (washed with dry THF and dried at 80 °C) in dry THF (20 mL) under
an atmosphere of argon was added a small crystal of iodine. Bromobenzene (2.47 g,
15.8 mmol, 10 eqv) in dry THF (5 mL) was added dropwise over 10 min. The mixture
was then heated to 50 °C for 3 h with good stirring. The grey metallic solution was
allowed to cool and then added slowly via cannula to a separate flask containing
a stirred mixture of compound 5 (400 mg, 1.58 mmol, 1 eqv), copper(I) iodide

90
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
(1.49 g, 7.85 mmol, 5 eqv) in dry THF (10 mL) under a steady stream of argon. The
resulting mixture was heated to 50 °C with good stirring for 4 h. The reaction was
quenched by the addition of a sat. aq. NH4Cl (50 mL) and extracted with ether
(3 Â 100 mL). The combined organic extracts were dried (MgSO4) and concentrated
in vacuo to afford a yellow oil. Purification by flash chromatography using ethyl ac-
etate/hexane (2:3, v/v) gave the known title compound [4] as a pale yellow oil (294 mg,
1
81.4%). H (270 MHz) (CDCl3) d 7.12–7.29 (5H, m, Ph–H), 5.29–5.33 (1H, t, J 6.9,
C2–H), 5.20–5.29 (1H, t, J 7, C6–H), 4.08–4.10 (2H, d, J 6.9, C1–H2), 3.26 (2H, s,
C8–H2), 2.03–2.20 (4H, m, C4–H2, and C5–H2), 1.65 (3H, s, C9–H3), 1.52 (3H, s,
C10–H3), 1.35 (1H, br, C1–OH). 13C NMR (67.8 MHz) (CDCl3) d 140.2, 138.8,
134.6, 128.6 (2C), 128 (2C), 127 (2C), 123.6, 59.1, 46.1, 39.4, 26.2, 16.1, 15.6. LRMS
(EI) m/z 230 (Mþ), 212, 199 (Mþ À CH2OH), 185, 172, 157, 144, 117, 105, 91
ðCH2Ph), 81, 71, 55 (100%). HRMS (EI) m/z exact mass calculated for C16H22O
230.16706; found 230.16652.
8-Phenyl-3,7-dimethyl-2E,6E-octadien-1-bromide ð6Þ. Compound
4 (202 mg,
0.87 mmol) in ether (3 mL) was stirred at 0 °C for 30 min, then PBr3 (87.3 mg,
0.32 mmol, 0.36 eqv) in ether (1 mL) was added dropwise over 10 min in the absence
of light. The reaction was stirred at 0 °C for 3 h. The mixture was poured onto
crushed ice-water (10 mL) and extracted with ether (3 Â 10 mL). The combined ex-
tracts were washed with 10% aq. NaHCO3 (2 Â 10 mL) and water (1 Â 10 mL).
The organic extract was dried (MgSO4) and concentrated in vacuo to give a pale yel-
low oil, which was taken up in ether/hexane (5:1, v/v) and passed through a small
column of silica (500 mg). Concentration in vacuo afforded the title compound as a
pale yellow oil (233 mg, 90.5%). mmax (neat)/cmÀ1 3058, 3024, 2974, 2920, 2854,
1948, 1878, 1805, 1655, 1601, 1493, 1450, 1384, 1076, 891, 732. 1H (270 MHz)
(CDCl3) d 7.14–7.34 (5H, m, Ph–H), 5.49–5.56 (1H, td, J 1.1, and 8.4, C2–H),
5.17–5.24 (1H, t, J 8.1, C6–H), 3.99–4.02 (2H, d, J 8.4, C1–H2), 3.26 (2H, s, C8–
H2), 2.02–2.18 (4H, m, C4–H2, and C5–H2), 1.71 (3H, s, C9–H3), 1.53 (3H, s,
C10–H3). LRMS (EI) m/z 294 (Mþ 81Br) 1%, 292 (Mþ 79Br) 1%, 279, 255, 213
(Mþ À Br), 145 (100%), 91, 81, 79, 49, 41. HRMS (EI) m/z exact mass calculated
for C16H21 79Br 292.08266; found 292.08253.
Ethyl 10-phenyl-4E,8E-ethoxycarbonyl-5,9-dimethyl-decadienoate ð8Þ. A 60% dis-
persion of NaH in oil (20.4 mg, 0.54 mmol, 1.05 eqv) was washed with dry THF
(5 mL) and decanted. Dry THF (5 mL) was added via cannula and then diethyl mal-
onate (0.41 g, 2.26 mmol, 5 eqv) in dry THF (5 mL) was added slowly via cannula at
0 °C over 30 min. The mixture was allowed to warm to ambient temperature over 2 h.
Compound 6 (0.15 g, 0.51 mmol) in dry THF (2 mL) was added via cannula over
30 min, and then the mixture was stirred at ambient temperature overnight. The re-
action was quenched by the addition of sat. NH4Cl (10 mL), and extracted with ether
(3 Â 20 mL). The combined extracts were washed with water (2 Â 30 mL), dried
ðMgSO4Þ, and concentrated in vacuo to give a yellow oil. Purification by flash chro-
matography using ethyl acetate/hexane (1:5, v/v) gave the title compound as a clear
oil (113 mg, 59.5%). mmax (neat)/cmÀ1 3058, 2983, 2935, 1737, 1601, 1450, 1369,
1
1269, 1150, 1037, 860, 737, 702. H NMR (270 MHz) ðCDCl3Þ d 7.14–7.30 (5H,
m, Ph–H), 5.18–5.23 (1H, td, J 1.1, and 7.9, C4–H), 5.07–5.13 (1H, td, J 1.1, and

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
91
7.9, C8–H), 4.14–4.22 (4H, m, CO2C–H2x2Þ, 3.31–3.26 (1H, t, J 7.7, C2–H), 3.26
(2H, s, C10–H2), 2.58–2.63 (2H, dd, J 7.7, and 7.9, C3–H2), 2.01–2.14 (4H, m,
C6–H2, and C7–H2), 1.64 (3H, s, C11–H3), 1.52 (3H, s, C12–H3), 1.25–1.31 (6H,
m, CO2CH2C–H3x2Þ. 13C NMR (67.8 MHz) (CDCl3) d 169.2, 140.4, 138.2, 134.5,
128.8, 128.1, 126.1, 125.8, 118.9, 61.2, 52.3, 46.2, 39.6, 27.5, 26.5, 16.1, 15.7, 14.0.
LRMS (EI) m/z 372 (Mþ), 327 (Mþ À OCH2CH3Þ, 226, 159, 91 (CH2 Ph), 77
(Ph). Found: C, 74.29; H, 9.07, C23H32O4 requires C, 74.16; H, 8.66.
Ethyl 10-phenyl-4E,8E-5,9-dimethyl-decadienoate ð9Þ. Under an argon atmosphere
compound 8 (51 mg, 0.14 mmol), NaCl (18.9 mg, 0.33 mmol, 2.35 eqv), water (50 lL),
and N; N0-dimethylformamide (2 mL) were placed under reflux for 20 h. The mixture
was diluted with water (5 mL) and extracted with ether (3Â 5 mL). The combined ex-
tracts were washed with water (2 Â 8 mL), dried (MgSO4), and concentrated in vacuo
to yield a brown oil. Purification by flash chromatography using ethyl acetate/hexane
(1:19, v/v) gave the title compound (19.2 mg, 46.7%, 62.8% based on recovered start-
ing material) followed by unreacted starting material (13.1 mg). 1H NMR (270 MHz)
(CDCl3) d 7.15–7.30 (5H, m, Ph–H), 5.19–5.24 (1H, td, J 0.7, and 6.4, C4–H), 5.07–
5.14 (1H, m, C8–H), 4.08–4.16 (2H, q, J 7.2, CO2C–H2), 3.26 (2H, s, C10–H2), 2.27–
2.36 (4H, m, C2–H2, and C3–H2), 2.00–2.17 (4H, m, C6–H2, and C7–H2), 1.62 (3H,
s, C11–H3), 1.52 (3H, s, C12–H3), 1.23–1.28 (3H, t, J 7.2, CO2CH2C–H3). 13C NMR
(67.8 MHz) (CDCl3) d 173.4, 140.5, 136.4, 134.4, 128.8 (2C), 128.2 (2C), 126.3, 125.9,
122.6, 60.2, 46.3, 39.6, 34.6, 30.4, 26.6, 16.1, 15.9. LRMS (EI) m/z 301 ðMþ þ 1Þ, 300
(Mþ), 255 (Mþ À OCH2CH3Þ, 209 (Mþ À CH2PhÞ, 181, 145, 117, 91 ðCH2PhÞ, 67.
HRMS (EI) m/z exact mass calculated for C20H28O2 300.20893; found 300.20819.
10-Phenyl-4E,8E-5,9-dimethyl-decadienoic acid ð10Þ. Compound
9
(0.4 g,
1.3 mmol) in ethanol (5 mL) and water (5 mL) was stirred at ambient temperature.
Crushed KOH pellets (0.75 g, 13.3 mmol, 10 eqv) were added slowly, and then the
mixture was refluxed overnight. The mixture was acidified with 2.0 M aq. HCl
(20 mL) and extracted with ether (3 Â 30 mL). The organic extracts were combined
and washed with water (2 Â 40 mL), dried (MgSO4), and concentrated in vacuo to
give a pale yellow oil. Purification by flash chromatography using ethyl acetate/ hex-
ane (2:3, v/v) gave the title compound as a clear oil (0.30 g, 85.2%). 1H NMR
(270 MHz) (CDCl3) d 11.10–12.00 (1H, br, C1–OH), 7.14–7.30 (5H, m, Ph–H),
5.18–5.24 (1H, td, J 0.7, and 7.0, C4–H), 5.09–5.14 (1H, m, C8–H), 3.26 (2H, s,
C10–H2), 2.28–2.38 (4H, br m, C2–H2, and C3–H2), 2.00–2.16 (4H, m, C6–H2,
and C7–H2), 1.62 (3H, s, C11–H3), 1.52 (3H, s, C12–H3). 13C NMR (67.8 MHz)
(CDCl3) d 179.5, 140.5, 136.8, 134.5, 128.8 (2C), 128.2 (2C), 126.2, 125.9, 122.2,
110.3, 46.2, 39.5, 34.2, 26.5, 23.3, 15.9, 15.8. LRMS (EI) m/z 272 (Mþ), 195
(Mþ À Ph), 181 (Mþ À CH2Ph), 165, 112, 91 (CH2Ph), 77 (Ph). HRMS (EI) m/z ex-
act mass calculated for C18H24O2 272.17763; found 272.17665.
Ethyl 2-(diethoxyphosphinyl)-10-phenyl-5,9-dimethyl-4E,8E-decadienoate ð11Þ. To
a solution of NaH (46.7 mg, 1.2 mmol, 1.2 eqv, 60% dispersion in oil, washed with
dry THF (5 mL) removed via cannula) in dry THF (7 mL) was added tri-
ethylphosphonoacetate (0.29 g, 1.33 mmol, 1.3 eqv) in dry THF (3 mL) via cannula.
After 30 min the mixture was cooled to 0 °C and transferred via cannula over 30 min
to a mixture of bromide 6 (0.3 g, 1.02 mmol, 1 eqv) in dry THF (8 mL). The resulting

92
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
mixture was allowed to warm slowly to ambient temperature. After 18 h the reaction
was quenched by addition of water (20 mL). The mixture was extracted with ethyl
acetate (4 Â 20 mL), combined, dried (MgSO4), and concentrated in vacuo to give
an orange oil. Purification by flash chromatography using ethyl acetate/hexane
(1:1, v/v) gave the title compound as a clear oil (196 mg, 44.1%). 1H NMR (270 MHz)
(CDCl3) d 7.13–7.30 (5H, m, Ph–H), 5.18–2.23 (1H, td, J 1.1, and 6.3, C4–H), 5.05–
5.10 (1H, t, J 6.8, C8–H), 4.09–4.23 (6H, m, POC–H2x2, and CO2C–H2Þ, 3.26 (2H, s,
C10–H2), 2.88–3.01 (1H, ddd, J 4.0, 11.0, and 26.6, C2–H), 2.47–2.78 (2H, m, C3–
H2), 1.99–2.11 (4H, m, C6–H2, and C7–H2), 1.64 (3H, s, C11–H3), 1.51 (3H, s,
C12–H3), 1.23–1.37 (9H, m, POCH2C–H3x2, and CO2CH2C–H3). 13C NMR
(67.8 MHz) (CDCl3) d 168.9, 140.5, 138.0, 134.6, 128.2, 127.9, 126.1, 125.9, 120.7,
120.5, 62.7, 62.6, 62.5, 47.2, 45.3, 39.6, 26.6, 25.8, 25.7, 16.5, 16.4, 16.1, 15.8, 14.2.
FAB LRMS: 459.3 ðM þ NaÞþ, 437.3 (M þ 1; 100%Þþ, 391.3 (M À CH3CH2O),
293.2, 291.2, 247.1, 224.1, 197.1, 179.1, 157.1, 151, 145.1, 129.1, 117.1. FAB HRMS:
m/z exact mass calculated for C24H37NaO5 459.2276; found 459.2273. Found: C,
65.11; H, 8.67; P, 6.90, C24H37O5P requires C, 66.04; H, 8.54; P, 7.10.
2-(Diethoxyphosphinyl)-10-phenyl-5,9-dimethyl-4E,8E-decadienoic acid ð12Þ. Com-
pound 11 (143 mg, 0.33 mmol) and 2 M aq. NaOH (0.6 mL, 1.3 mmol) in ethanol
(10 mL) were refluxed for 4 h. The mixture was allowed to cool to ambient temper-
ature and acidified with 1 M aq. HCl (5 mL). The mixture was extracted with ethyl
acetate (4 Â 20 mL), and the combined extracts were washed with water ð2 Â 5 mL),
dried (MgSO4), and concentrated in vacuo to give a yellow oil. Flash chromato-
graphy using methanol/ethyl acetate (1:19, v/v) gave the title compound as a yellow
oil (0.19 g, 88.1%). 1H NMR (270 MHz) (CDCl3) d 7.13–7.29 (5H, m, Ph–H),
5.13–5.23 (2H, m, C4–H, and C8–H), 4.12–4.23 (4H, q, J 7.0, POC–H2x2Þ, 3.26
(2H, s, C10–H2), 2.93–3.06 (1H, m, C2–H), 2.43–2.70 (2H, m, C3–H2), 1.97–2.15
(4H, m, C6–H2, and C7–H2), 1.61 (3H, s, C11–H3), 1.51 (3H, s, C12–H3), 1.28–
1.33 (6H, t, J 7.0, POCH2C–H3). LRMS (EI) m/z 409 (Mþ + 1), 391 (Mþ À OH),
345, 305, 224, 179 ðPOðOEtÞ CHCOÞ, 144, 117, 91 ðCH2PhÞ, and 67. FAB LRMS:
2
m/z mass calculated for C22H33O5P 408.48; 431.2 ðM þ NaÞþ, 391.2 ðM À OHÞþ,
247.1, 237.1, 191.1, 179.1 ðPOðOEtÞ CHCOÞ, 165.1, 145.1 ðC11H13Þ, 129.1
2
ðC10H10Þ, 117.1 ðC9H10Þ, 105.1 ðC8H7Þ.
2-(Phosphono)-10-phenyl-5,9-dimethyl-4E,8E-decadienoic acid ð13Þ. To a stirred
mixture of the acid 12 (134 mg, 0.33 mmol) and collidine (0.2 mL, ꢀ5 eqv) in
CH2Cl2 (6 mL) at 0 °C was added trimethylsilyl bromide (0.2 mL, ꢀ5 eqv). The mix-
ture was stirred at 0 °C for 30 min and then warmed to ambient temperature and stir-
ring was continued overnight. Toluene (8 mL) was added and the mixture was then
concentrated in vacuo to remove all the volatile components. A solution of 0.5 M aq.
NaOH (5.5 mL) was added and the resulting clear solution was stirred for 22 days,
after which time all the starting material had been consumed as adjudged by TLC.
The reaction mixture was acidified with 2 M aq. HCl until pH 1, extracted with ethyl
acetate (4 Â 20 mL), and the combined organic extracts were dried (MgSO4) and
concentrated in vacuo affording the title compound as a yellow oil (67.6 mg,
58.4%). The oil was dried under in vacuo at 0.1 mm Hg for 10 h at 40 °C to ensure
complete removal of toluene. 1H NMR (270 MHz) (D2OÞ d Selected 7.14–7.32

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
93
(5H, m, Ph), 5.10–5.21 (2H, m, C4–H, and C8–H), 3.25 (2H, s, C10–H2), 2.32–2.78
(3H, m, C2–H, and C3–H2), 1.910–2.09 (4H, m, C6–H2, and C7–H2), 1.63 (3H, s,
C11–H3), 1.58 (3H, s, C12–H3). 31P NMR (109.36 MHz) ðD2OÞ d 22.3 (1P, s,
POðOHÞ Þ. LRMS (ESI) m/z 353 and 352 (Mþ) 100%.
2
8-Phenyl-3,7-dimethyl-2E,6E-octadien-1-phenyl sulphone ð7Þ. Compound
6
(195 mg, 0.66 mmol) in dry N; N0-dimethylformamide (5 mL) was stirred at 0 °C.
The sodium salt of benzenesulphinic acid (115 mg, 0.7 mmol, 1.01 eqv) was added
in small portions over 20 min. The mixture was stirred at 0 °C for 1 h and then at am-
bient temperature overnight. The mixture was diluted with ether (30 mL) and washed
with water (3 Â 20 mL). The organic extract was dried (MgSO4) and concentrated in
vacuo to give a light brown oil. Purification by flash chromatography using ethyl ac-
1
etate/hexane (3:7, v/v) gave the title compound as a yellow oil (209 mg, 88.9%). H
NMR (270 MHz) (CDCl3) d 7.85–7.87 (2H, dd, J 1.5, and 8.4, SO2Ph–C20–H,
C60–H), 7.45–7.65 (3H, m, SO2Ph–C30–H, C40–H, C50–H), 7.13–7.41 (5H, m, Ph),
5.14–5.27 (2H, m, C2–H, and C6–H), 3.78–3.81 (2H, d, J 8.06, C1–H2), 3.26 (2H,
s, C8–H2), 1.99–2.12 (4H, m, C4–H2, and C5–H2), 1.51 (3H, s, C9–H3), 1.31 (3H,
s, C10–H3). 13C NMR (67.8 MHz) ðCDCl3Þ d 146.1, 140.2, 133.1, 128.9, 128.8,
128.5, 128.2, 125.9, 125.319, 56.1, 46.1, 39.6, 26.2, 16.1, 15.8. LRMS (EI) m=z 354
(Mþ), 229 (100%), 213 (Mþ À SO2Ph), 197, 183, 171, 155 ðCH2SO2PhÞ. Found: C,
74.22; H, 7.31, C22H26O2S requires C, 74.54; H, 7.39.
3,7-Dimethyl-2E,6-octadien-1-phenyl sulphone ð14Þ. Geranyl bromide (8.69 g,
40.06 mmol) in dry N; N0-dimethylformamide (20 mL) was added dropwise to a stir-
red suspension of the sodium salt of benzenesulphinic acid (6.57 g, 40.06 mmol) in
dry N; N0-dimethylformamide (20 mL) at 0 °C over 1 h. The reaction mixture was left
to stir at 0 °C for a further 2 h and warmed to ambient temperature and stirred over-
night. The reaction mixture was poured into ice-water (200 mL) and extracted with
ether (5 Â 100 mL). The combined organic extracts were washed with water
(5 Â 250 mL), dried (MgSO4), and concentrated in vacuo to yield a yellow oil
(10.16 g, 91.2%). Purification by flash chromatography using ethyl acetate/hexane
(1:4, v/v) afforded the known title compound [19] as a light yellow oil (8.13 g,
72%). Purification by distillation in vacuo (15 mm Hg) resulted in rapid decomposi-
tion of the product. mmax (neat)/cmÀ1 3062, 2967, 2922, 2857, 1972, 1903, 1819, 1678,
1585, 1447, 1405, 1386, 1307, 1150, 1086, 899. 1H NMR (270 MHz) (CDCl3) d 7.85–
7.88 (2H, m, C20–H, and C60–H), 7.61–7.66 (1H, m, C40–H), 7.50–7.55 (2H, dd, J 7.2,
and 7.2, C30–H, and C50–H), 5.16–5.22 (1H, t, J 8.0, C2–H), 5.01–5.06 (1H, m, C6–
H), 3.79–3.82 (2H, d, J 8.0, C1–H2), 1.99–2.08 (4H, m, C4–H2, and C5–H2), 1.69
(3H, s, C10–H3), 1.59 (3H, s, C8–H), 1.32 (3H, s, C9–H). LRMS (EI) m/z 278.4
(Mþ), 155.1 (PhSO2PhÞ, 137 (Mþ À SO2Ph) (100%), 141 ðSO2PhÞ, 121.1, 81, 77 (Ph).
8-Hydroxy-3,7-dimethyl-2E,6E-octadien-1-phenyl-sulphone ð15Þ. Compound 14
(5 g, 18 mmol) was reacted with tert-butyl hydroperoxide (6.13 mL, 44.9 mmol,
2.5 eqv) and SeO2 (99.7 mg, 0.89 mmol, 5 mol%). A standard work-up gave a crude
oil that was reduced using NaBH4 (0.68 g, 17.9 mmol, 1 eqv) over 30 min at 0 °C.
Standard work-up gave an oil. Purification by flash chromatography using ethyl ac-
etate/hexane (3:7, v/v) gave the known title compound [9] as a viscous yellow oil
(4.25 g, 80.3%). mmax (neat)/cmÀ1 3064, 2978, 2931, 2875, 1979, 1907, 1819, 1680,

94
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
1
1585, 1244, 1196, 1149, 1089. H NMR (270 MHz) (CDCl3) d 7.85–7.89 (2H, dd, J
1.5, and 7.0, C20–H and C60–H), 7.62–7.65 (1H, dd, J 1.5, and 7.0, C40–H), 7.52–7.58
(2H, m, C30–H and C50–H), 5.31–5.36 (1H, m, C2–H), 5.16-5.22 (1H, td, J 1.1, and
8.05, C6–H), 3.99 (2H, s, C8–H2), 3.79–3.82 (2H, d, J 8.05, C1–H2), 2.08–2.16 (4H,
m, C4–H2, and C5–H2), 1.65 (3H, s, C9–H3), 1.37 (3H, s, C10–H3). 13C NMR
(67.8 MHz) (CDCl3) d 145.9, 138.9, 135.5, 133.5, 128.9 (2C), 128.3 (2C), 124.5,
110.4, 68.5, 55.9, 39.1, 25.4, 16.1, 13.6. LRMS (EI) m/z 294.1 (Mþ), 281.1
(Mþ À OH), 155.9 ðCH2SO2PhÞ, 153.1 (Mþ À SO2Ph), 119, 107.1, 93 (100%), 77
(Ph). HRMS (EI) m/z exact mass calculated for C16H22O3S 294.12896; found
294.12837.
8-[(20 -Tetrahydropyranyl)-oxy]-3,7-dimethyl-2E,6E-octadi-en-1-phenyl-sulphone
ð16Þ. To compound 15 (2 g, 6.80 mmol) in dry CH2Cl2 (20 mL) was added toluene-
sulphonic acid (64 mg, 0.34 mmol, 5 mol%). The mixture was allowed to stir at
0 °C for 30 min, and then dihydropyran (1.14 g, 13.6 mmol, 2 eqv) in dry CH2Cl2
(5 mL) was added slowly over 30 min. The mixture was stirred at ambient tempera-
ture overnight. The solvent was removed in vacuo and the residue taken up in ether
(50 mL), washed successively with 10% aq. NaHCO03 (2 Â 30 mL) and water
ð3 Â 30 mL). The combined organic extracts were dried ðMgSO4Þ and concentrated
in vacuo to yield a brown oil. Purification by flash chromatography using ethyl ac-
etate/hexane (3:7, v/v) gave the known title compound [20] as a pale yellow oil
(2.52 g, 97.9%). mmax (neat)/cmÀ1 3060, 2923, 2868, 1978, 1902, 1815, 1722, 1685,
1
1599, 1446, 1241, 1149, 1078, 976, 869. H NMR (270 MHz) (CDCl3) d 7.86–7.88
(2H, d, J 8.05, C20–H, and C60–H), 7.61–7.67 (1H, dd, J 2.13, and 8.05, C40–H),
7.50–7.56 (2H, t, J 8.05, C30–H, and C50–H), 5.34–5.38 (1H, m, C2–H), 5.17–5.23
(1H, t, J 7.9, C6–H), 4.58–4.61 (1H, t, J 6.59, THP-C10–H), 4.08–4.12 (1H, d, J
11.7, THP-C60ax–H), 3.75–3.92 (4H, m, C1–H2, and C8–H2), 3.47–3.55 (1H, m,
THP-C60eq-H), 2.01–2.08 (4H, m, C4–H2, and C5–H2), 1.45–1.87 (9H, br m,
THP-C30–C40–C50–3H2, and C10–H3), 1.32 (3H, s, C9–H3). Found: C, 66.67; H,
8.17, C21H30O4S requires C, 66.63; H, 7.99. LRMS (EI) m/z 396 (Mþ) 30%, 312
(100%), 294, 277, 135, 118, 102, 85. HRMS (EI) m/z exact mass calculated for
(þNH4 enhanced) C21H34NO4S 396.22085; found 396.22076.
8-Phenyl-3,7-dimethyl-2E,6E-octadien-1-phenyl sulphone ð7Þ using CuI/PhMgBr.
Compound 16 (0.5 g, 1.32 mmol) was reacted with a 3.0 M solution of PhMgBr in
ether (4.4 mL, 13.22 mmol, 10 eqv) catalysed by CuI (1.26 g, 6.61 mmol, 5 eqv). The
usual work-up afforded a mixture of products. Purification by flash chromatography
using ether/hexane (1:4, v/v) afforded known (4b) 1,8-diphenyl-3,7-dimethyl-2E,6E-
octa-diene and biphenyl (172 mg, 45% approx.), followed by the title compound as
1
a yellow oil (98.6 mg, 21.1%). TLC; H. Data for 1,8-diphenyl-3,7-dimethyl-2E,6E-
1
octa-diene 85 and biphenyl H NMR (270 MHz) (CDCl3) in accordance with the
1H data reported by Wiemer (4b): Selected d 7.10–7.59 (ꢀ10H, m, Ph–Hx2), 5.33–
5.37 (1H, m, C2–H), 5.21–5.25 (1H, m, C6–H), 3.30–3.34 (2H, d, J 7.3, C1–H2),
3.26 (2H, s, C8–H2), 2.08–2.17 (4H, m, C5–H2, and C6–H2), 1.70 (3H, s, C9–H3),
1.51 (3H, s, C10–H3).
8-Hydroxy-3,7-dimethyl-2E,6E-octadien-1-chloroacetate ð18Þ. Following a stan-
dard SeO2 oxidation procedure, compound 18 (1.5 g, 6.51 mmol) was reacted with

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
95
SeO2 (72.2 mg, 0.65 mmol, 10 mol%), tert-butyl hydroperoxide (3 mL, 23.4 mmol,
3.6 eqv) and benzoic acid (79.4 mg, 0.65 mmol, 10 mol%) in CH2Cl2 (20 mL). The
usual work-up yielded a pale yellow oil. Purification by flash chromatography using
ether/hexane (3:7, v/v) yielded the known title compound (5) as a colourless oil
(0.69 g, 42.8%). mmax (neat)/cmÀ1 3386, 2979, 2933, 1741, 1672, 1450, 1414, 1385,
1
1363, 1246, 1194, 845, 787, 7480. H NMR (270 MHz) (CDCl3) d 5.33–5.40 (2H,
m, C2–H, and C6–H), 4.69–4.72 (2H, d, J 7.33, C1–H2), 4.06 (2H, s, C12–H2),
3.99 (2H, s, C8–H2), 2.06–2.19 (4H, m, C4–H2, and C5–H2), 1.73 (3H, s, C9–H3),
1.66 (3H, s, C10–H3). 13C NMR (67.8 MHz) (CDCl3) 167.6, 142.9, 135.4, 125.2,
118.1, 68.7, 63.2, 41.9, 38.9, 25.7, 16.8, 13.9.
8-Benzoxy-3,7-dimethyl-2E,6E-octadien-1-ol ð20Þ. Following a standard proce-
dure, compound 18 (0.43 g, 1.74 mmol) was reacted with benzoyl chloride (0.37 g,
2.62 mmol, 1.5 eqv) in pyridine (5 mL) and DMAP (25 mg, 10 mol%). The mixture
was left to stir for 24 h. The usual work-up gave a brown oil. Purification by flash
chromatography using ether/hexane (3:2, v/v) gave a yellow oil (232 mg, 38.1%). Un-
stable chloroacetate 19 (0.22 g, 0.63 mmol) was hydrolysed with 0.1 M NH4OH
(3 mL) in aqueous methanol (9:1, v/v). The mixture was stirred for 1 h, and methanol
was then removed in vacuo. The residue was dissolved in ether (30 mL) and washed
with water (2 Â 15 mL), dried (MgSO4), and concentrated in vacuo to give an oil. Pu-
rification by flash chromatography using ethyl acetate/hexane (1:4, v/v) gave the
known title compound [5] as a clear oil (72.4 mg, 42.1%). 1H NMR (270 MHz)
(CDCl3) d 8.04–8.12 (2H, m, C20–H, and C60–H), 7.53–7.61 (1H, m, C40–H), 7.41–
7.50 (2H, m, C30–H, and C50–H), 5.50–5.55 (1H, t, J 6.8, C2–H), 5.39–5.50 (1H,
m, C6–H), 4.71 (2H, s, C8–H2), 4.14–4.16 (2H, d, J 6.8, C1–H2), 2.18–2.27 (2H,
m, C5–H2), 2.07–2.15 (2H, m, C4–H2), 1.74 (3H, s, C9–H3), 1.68 (3H, s, C10–H3),
1.38 (1H, br, C1–OH). 13C NMR (67.8 MHz) (CDCl3) d 166.5, 138.9, 133.6, 132.9,
130.4, 130.1, 129.6, 128.8, 128.5, 128.4, 124.0, 70.5, 59.4, 38.9, 25.9, 16.2, 14.0.
For complete characterisation this compound was converted to 8-benzoxy-3,7-di-
methyl-2E,6E-octadien-1-acetate, using pyridine (10 mL), DMAP (10 mg, cat.),
and acetic anhydride: Standard work-up and flash chromatography using ethyl
acetate/hexane (1:10, v/v) to provide 68.2 mg (86.6%) of a clear oil. d1H (CDCl3)
8.25–8.28 (2H, m, C20–H, and C60–H), 8.14–8.18 (1H, m, C40–H), 7.51–7.69 (2H,
m, C30–H, and C50–H), 5.61–5.66 (1H, td, J 1.1, and 14.66, C2–H), 5.44–5.49 (1H,
td, J 1.1, and 15.39, C6–H), 4.81 (2H, s, C8–H2), 4.68–4.70 (2H, d, J 6.96, C1–
H2), 2.28–2.36 (2H, m, C5–H2), 2.18–2.24 (2H, m, C4–H2), 2.15 (3H, s, C12–H3),
1.84 (3H, s, C9–H3), 1.82 (3H, s, C10–H3). LRMS (CI) m=z 334 ðM þ NH4Þ, 257,
196, 135 (100), 105. HRMS (EI) m=z exact mass calculated for ðþNH4 enhanced)
C19 H28 NO4 334.20183; found 334.20155.
8-Benzoxy-3,7-dimethyl-2E,6E-octadien-1-phenyl sulphone ð17Þ via bromide ð21Þ.
Compound 20 (200 mg, 0.73 mmol) in dry CH2Cl2 (5 mL) was reacted with NBS
(195 mg, 1.1 mmol, 1.5 eqv) and DMS (81.5 mg, 1.31 mmol, 1.8 eqv). The usual
work-up afforded crude 21, which was used without further purification. Crude 21
was taken up in N; N0-dimethylformamide (5 mL) and stirred for 30 min at 0 °C.
The sodium salt of benzenesulphinic acid (126 mg, 0.77 mmol, 1.05 eqv) in N; N0-dim-
ethylformamide (5 mL) was added slowly over 20 min and stirred for 1 h at 0 °C, and

96
I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
then at ambient temperature overnight. The usual work-up gave a yellow oil. Puri-
fication by flash chromatography using ethyl acetate/hexane (1:3, v/v) gave the title
compound as a yellow oil (223 mg, 77.4%). mmax (neat)/cmÀ1 3064, 2982, 2935, 1756,
1
1686, 1583, 1449, 1272, 1030, 939, 748, 707. H NMR (270 MHz) (CDCl3) d 8.04–
8.13 (2H, m, C20–H, and C60–H), 7.86–7.88 (2H, d, J 6.6, C200–H, and C600–H),
7.41–7.66 (6H, m, C30–H, C40–H, C50–H, C300–H, C400–H, and C500–H), 5.44–5.49
(1H, t, J 8.1, C2–H), 5.18–5.24 (1H, t, J 7.7, C6–H), 4.70 (2H, s, C8–H2), 3.79–
3.82 (2H, d, J 8.1, C1–H2), 2.06–2.17 (4H, m, C4–H2, and C5–H2), 1.72 (3H, s,
C9–H3), 1.34 (3H, s, C10–H3). FAB LRMS: m/z 421.2 ðM þ NaÞþ, 399.2
ðM þ 1Þþ, 278.1 (M À PhCO2 þ 1), 277.1 (M À PhCO2), 189.1, 143, 135.1
(PhCO2CH2, 100%), 133.1, 121.1 (PhCO2), 105 (PhCO). FAB HRMS: m=z exact
mass calculated for C23H26NaSO4 421.1450; found 421.1450. Found: C, 68.61; H,
6.68; S, 7.83, C23H26O4S requires C, 69.32; H, 6.58; S, 7.83.
Acknowledgments
We thank the Manchester Metropolitan University (MMU) for funding and the
Microbiology Department at MMU for guidance regarding the antimicrobial stud-
ies. We thank Dr. Russell Cox (University of Bristol, UK) for valuable comments
regarding the preparation of this manuscript and Professor David F. Wiemer for
his generous help and advice, regarding the CuI mediated THPO-nucleophilic dis-
placements. Finally we thank the EPSRC mass spectrometry centre at Swansea
(UK) for high-resolution mass spectrometry services.
References
[1] (a) For two excellent reviews in this area see, A. Nadin, K.C. Nicolaou, Angew. Chem. Int. Ed. Engl.
35 (1996) 1622;
(b) S.A. Biller, K. Neuenschwander, M.M. Ponpipom, C.D. Poulter, Curr. Pharm. Des. 2 (1996) 1.
[2] J. Grunler, Biochem. Biophys. Acta 1212 (1994) 259.
[3] (a) R.S. Bhide, D.V. Patel, M.M. Patel, S.P. Robinson, L.W. Hunihan, E.M. Gordon, Biorg. Med.
Chem. Lett. 4 (1994) 2107;
(b) S. Clarke, Ann. Rev. Biochem. 61 (1992) 355;
(c) W.R. Schafer, J. Rine, Annu. Rev. Genet. 30 (1992) 209;
(d) C.A. Omer, J.B. Gibbs, Mol. Microbiol. 11 (1994) 219;
(e) P.J. Casey, M.C. Seabra, J. Biol. Chem. 271 (1996) 5289.
[4] (a) M. Mechelke, D.F. Wiemer, Tetrahedron Lett 39 (1998) 783;
(b) M. Mechelke, D.F. Wiemer, J. Org. Chem. 64 (1999) 4821;
(c) T.A. Spencer, T.J. Onofrey, R.O. Cann, J.S. Russell, L.E. Lee, D.E. Blanchard, A. Castro, P. Gu,
G. Jiang, I. Schechter, J. Org. Chem. 64 (1999) 807.
[5] I. Gaon, T.C. Turek, V.A. Weller, R.L. Edelstein, S.K. Singh, M.D. Distefano, J. Org. Chem. 61
(1996) 7738.
[6] S.B. Long, P.J. Casey, S. Beese, Biochemistry 37 (1998) 9612.
[7] S. Holstein, D.M. Cermak, R. Hohl, K. Lewis, D.F. Wiemer, Bioorg. Med. Chem. 6 (1998) 687.
[8] E.J. Corey, C.U. Kim, M. Takeda, Tetrahedron Lett. 42 (1972) 4339.
[9] I.J.S. Fairlamb, J.M. Dickinson, M. Pegg, Tetrahedron Lett. 42 (2001) 2205, The SeO2 reaction gave
the aldehyde as the major product (14.3:1, as shown by HRGCMS) prior to reduction with NaBH4.

I.J.S. Fairlamb et al. / Bioorganic Chemistry 31 (2003) 80–97
97
E-Selectivity was confirmed by quantitative n.O.e studies (pulse delay ¼ 5 s, IRATN ¼ 150): a small
n.O.e is observed between the terminal vinyl proton and the Z-methyl protons (0.2%), whereas an
n.O.e of 1.9% is observed from the terminal vinyl proton to the E-methylene protons.
[10] National Committee for Clinical Laboratory Standards. Reference method for broth dilution for
antifungal susceptibility testing of yeast. National Committee for Clinical Laboratory Standards,
Villanova, PA (USA).
[11] (a) Squalestatin S1 is a potent nanomolar inhibitor of SQS. In our antimicrobial assay the MIC for
S1 against C. albicans was determined to be < 2lg/mL. The reported MIC for S1 against C. albicans
is between 6–16 lg/mL C. Dufresne, K.E. Wilson, D. Zink, J. Smith, J.D. Bergstrom, M. Kurtz, D.
Rew, M. Nallin, R. Jenkins, K. Bartizal, C. Trainor, G. Bills, M. Meinz, L. Huang, J. Onishi, J.
Milligan, M. Mojena, F. Pelaez, Tetrahedron 48 (1992) 10221;
(b) C. Dufresne, K.E. Wilson, D.L. Zink, J.D. Bergstrom, D. Rew, J. Smith, D.L. Singh, R.B.
Lingham, M. Mojena, C. Cascales, F. Pelaez, J.B. Gibbs, J. Nat. Prod. 56 (1993) 1923;
(c) N.S. Watson, R. Bell, C. Chan, B. Cox, J.L. Hutson, S.E. Keeling, B.E. Kirk, P.A. Procopiou, I.P.
Steeples, J. Widdowson, Bioorg. Med. Chem. Lett. 3 (1993) 2541.
[12] SQS is an active enzyme in E. coli: see http://www.genome.ad.jp/kegg/kegg2.htm.
[13] The MIC was determined using a micro-dilution procedure (see Ref. [10]). The agar media was
prepared by incorporation of compound 15 at various concentrations. The MIC was determined as
the lowest concentration of 15 where no visible growth of the organism was observed..
[14] L.H. Cohen, A.R.P.M. Valentijn, L. Roodenburg, R.E.W. van Leeuwen, R. Holger Huisman, R.J.
Lutz, G.A. van der Marel, J.H. van Boom, Biochem. Phamacol. 49 (1995) 839.
[15] L.H. Cohen, E. Pieterman, R.E.W. van Leeuwen, J. Du, P. Negre-Aminou, A.R.P.M. Valentijn, M.
Overhand, G.A. van der Marel, J.H. van Boom, Biochem. Phamacol. 57 (1999) 365.
[16] K.A.H. Chehade, D.A. Andres, H. Morimoto, H.P. Spielmann, J. Org. Chem. 65 (2000) 3027.
[17] A. Szkopinska, G. Swieewska, F. Karst, Biochem. Biophys. Res. Commun. 267 (2000) 473.
[18] M.S. Brown, J.L. Goldstein, Science 232 (1986) 34.
[19] R.V.M. Campbell, L. Crombie, D.A.R. Findley, R.W. King, G. Pattenden, D.A. Whiting, J. Chem.
Soc. Perkin Trans. 1 (1975) 897.
[20] J.A. Marshall, R.C. Andrews, J. Org. Chem. 50 (1985) 1602.