The synthesis of methoxy and keto mycolic acids containing methyl-trans-cyclopropanes

Article abstract of DOI:10.1016/j.tet.2013.04.134

The syntheses of a number of methoxy and keto-mycolic acids containing an α-methyl-trans-cyclopropane unit and with chain lengths identical to those reported in major homologues in natural samples are reported.

Full text of DOI:10.1016/j.tet.2013.04.134

Tetrahedron 69 (2013) 6285e6296
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
The synthesis of methoxy and keto mycolic acids containing
methyl-trans-cyclopropanes
Gani Koza, Maged Muzael, Richard R. Schubert-Rowles, Cornelia Theunissen,
*
Juma’a R. Al Dulayymi, Mark S. Baird
School of Chemistry, Bangor University, Bangor, Wales LL57 2UW, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
The syntheses of a number of methoxy and keto-mycolic acids containing an a-methyl-trans-cyclopro-
pane unit and with chain lengths identical to those reported in major homologues in natural samples are
reported.
Received 8 February 2013
Received in revised form 18 April 2013
Accepted 30 April 2013
Ó 2013 Elsevier Ltd. All rights reserved.
Available online 23 May 2013
Keywords:
Mycolic acids
Mycobacterium tuberculosis
trans-Cyclopropane
Methoxy-mycolic acid
Keto-mycolic acid
1. Introduction
with one cis-cyclopropane.5,6 In addition they include methoxy-
and keto-mycolic acids in which there is a trans-cyclopropane
Mycolic acids, e.g.,1 (Fig.1), are characteristic components of the
cells of mycobacteria and of a number of related organisms, such as
Rhodococcus and Nocardia, some of which are pathogenic to ani-
mals and humans.1e6 Their presence is thought to be linked to the
characteristic resistance of many such organisms to most current
antibiotics and other chemotherapeutic agents.7
substituted with a methyl group on the adjacent carbon distal from
the hydroxy acid, 5 and 6 (Fig. 2). The stereocentres in the and
-positions relative to the carboxylic group have both been found
a
b
to be in the R-configuration for all the mycolic acids examined,
irrespective of the other functional groups.8e12
Fig. 2. Common combinations of X and Y in M. tuberculosis mycolic acids.
Fig. 1. A generalised mycolic acid structure.
The presence of the b-hydroxy group and the relative configu-
The mycolic acids present as major constituents of the cell en-
ration between it and the alkyl chain has been shown to be capable
of altering the film molecular packing.13,14 Moreover, the absolute
configuration of these two chiral centres is necessary for efficient
recognition by T cells and the generation of an immune response
by the host organism against pathogenic mycobacteria;15 the
same is true for the anti-tumour properties of mycolic acid de-
velope of Mycobacterium tuberculosis can be divided into a number
of main groups, including a-mycolic acids with two cis-cyclopro-
panes as X and Y, 2, and methoxy-3 and keto-mycolic acids 4
* Corresponding author. Tel.: þ44 1248 382374; fax: þ44 1248 370528; e-mail
address: chs028@bangor.ac.uk (M.S. Baird).
rivatives.16 The balance of
a-mycolic acids 2, methoxy-3 and 5 and
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.04.134

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G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
keto-mycolic acids, such as 4 and 6 is characteristic of specific
bacteria;5,6 in each case, each class of mycolic acid is present as
a mixture of homologues. In the case of M. tuberculosis, the exact
role of each type in the pathogenesis of disease remains to be
confirmed, but the oxygenated mycolic acids have a particular in-
fluence on macrophage growth; strains lacking ketomycolates have
a reduced ability to grow within THP-1 cells.17,18 Moreover, the
absence of keto and methoxy-mycolates leads to attenuation of M.
tuberculosis in mice;19 the vaccine strain Mycobacterium bovis BCG-
Pasteur lacks methoxy-mycolates.20e22 M. tuberculosis controls host
innate immune activation through cyclopropane modification of
a glycolipid effector molecule.23e25 Cyclopropane stereochemistry
plays a key role in pathogenesis and immuno-modulatory function;
thus a mutant strain lacking the ability to produce trans-cyclopro-
panes enhances the macrophage inflammatory response.26 The
stereochemistry was shown to directly affect the interaction with
host cells to affect innate immune activation both positively and
negatively. Such MAs have a particular effect on the cell wall and
therefore on the sensitivity of mycobacterial species to hydropho-
bic antibiotics.27 The genes responsible for trans-cyclopropanation
have been examined,27,28 and cyclopropanation has been theoret-
ically modelled.29
by a modification of a standard method; see Supplementary data)
using lithium hexamethyldisilazide, then the derived mixture of
alkenes was hydrogenated using 2,4,6-triisopropyl sulfonylhy-
drazide, to produce the chain extended ester 10 (n¼7), ½a D25
þ7.61 (c
ꢀ
1.31, CHCl3). This was deprotected to produce the alcohol 11 (n¼7),
½
a 2D5
ꢀ
þ16.05 (c 1.19, CHCl3) (Scheme 1).
Scheme 1. (i) LiHMDS, THF, 69%; (ii) 2,4,6-triisopropyl sulfonylhydrazide, THF, 87%;
(iii) tetra-n-butyl ammonium fluoride, THF, 91%.
We have recently reported the synthesis of an
type 2,30 and of methoxy-mycolates of type 3 with either absolute
stereochemistry at the cis-cyclopropane or -methyl- -methoxy
fragment.31 We have also reported the synthesis of meromycolate
fragments containing the -methyl-trans-cyclopropane unit pres-
a-mycolate of
The alcohol was then converted into aldehyde 14, which was
coupled in the next step to the sulfone 13, prepared in three stan-
dard steps from alcohol 12. Reaction between the two compounds
in the presence of lithium hexamethyldisilazide led to a 70% yield of
an E/Z-mixture of alkenes, which was hydrogenated using di-imide
to produce the meromycolate fragment 15 after partial depro-
tection. Oxidation of 15 led to the aldehyde 16, ready for the final
coupling to produce the complete carbon skeleton of the mycolic
acid (Scheme 2).
a
b
a
ent in mycobacterial wax esters, again in a variety of stereochem-
istries, and provided evidence that the relative stereochemistry of
methyl and cyclopropane is as shown in 7, since the cyclopropane
region of the 1H NMR spectrum of this stereoisomer matches that of
the natural material, whereas that of an isomer with the opposite
relative stereochemistry of methyl group and cyclopropane is quite
different.32 Moreover, at least in the case of wax esters derived by
enzymatic BaeyereVilliger reaction of ketomycolates, the absolute
stereochemistry of this sub-unit appears to be as shown in 7.33
There is evidence that in most cases the methoxy and methyl
groups of mycolic acids 3 and 5 are S,S and that the a-methyl ketone
of ketomycolates is S, though it is not clear whether the stereo-
chemistry is important for biological effect.9,34,35 We have briefly
reported syntheses of protected ketomycolates containing both a-
methyl-trans- and cis-cyclopropane fragments, 6 and 4 that can be
adjusted to produce a variety of absolute stereochemistries and
chain lengths.36 However, deprotection of these led to epimerisa-
tion at the methyl-position adjacent to the ketone. More recently,
we have reported in full the synthesis of keto-MA containing cis-
cyclo-propanes.37 We now report in full the synthesis of both keto-
and methoxy-MA containing an
a-methyl-trans-cyclopropane
fragment 7 (Fig. 3).
Scheme 2. (i) N-Bromosuccinimide, PPh3, CH2Cl2, 91%; (ii) 1-phenyl-1H-tetrazol-5-
thiol, K2CO3, acetone, THF, 95%; (iii) H2O2, Mo7O24(NH4)6$4H2O, IMS, THF, 82%. (iv)
PCC, CH2Cl2, 91%; (v) LiHMDS, THF, 70%; (vi) KOOCN]NCOOK, AcOH/MeOH/THF, 75%;
(vii) LiAlH4, THF, 82%; (viii) PCC, CH2Cl2, 86%.
Fig. 3. A typical a-methyl-trans-cyclopropane fragment.
2. Results and discussion
The final coupling required the sulfone 20, prepared, as
described earlier for different chain lengths, from aldehyde 18
(Scheme 3).
Coupling of 16 and 20 with base, followed by saturation of the
derived alkenes led to the protected mycolic acid 21 (Scheme 4).
Deprotection using HF-pyridine and pyridine, followed by lithium
hydroxide produced the hydroxymycolic acid 23, the first example
As in other syntheses of mycolic acids, the molecules were
constructed from three fragments, one the fragment containing
group X, one group Y, the third the b-hydroxy acid part, and these
were linked through modified JuliaeKocienski reactions, followed
by hydrogenation of the derived mixture of E/Z-alkenes. The known
cyclopropane 8,32,33 was first coupled to sulfone 9 (n¼7) (prepared
of
a synthetic hydroxy-MA containing a trans-cyclopropane.

G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
6287
therefore consistent with no contribution from the epimerized
a-methyl ketone fragment.
In the same way, the aldehyde 26 was coupled to sulfone 27 and,
through a series of similar reactions (see Supplementary data) was
converted into the diastereomeric hydroxy-MA 28 and keto MA 29
(Fig. 4). Deprotection of 29, [
MeOH/THF/H2O gave approximately the same mixture of epimers
a
] þ3.0 (c 0.7, CHCl3), with LiOH$H2O,
25 as that derived from 24. Thus the product showed identical NMR
spectra and the specific rotation, ½a D26
þ5.3 (c 0.96, CHCl3), was
ꢀ
close to that above.
Scheme 3. (i) LiHMDS, THF, 94%; (ii) H2, Pd/C, 36%; (iii) 1-phenyl-1H-tetrazol-5-thiol,
K2CO3, acetone, 79%; (iv) HFepyridine, pyridine, THF, 81%; (v) acetic anhydride, pyri-
dine, toluene, 84%; m-chloroperbenzoic acid, NaHCO3, CH2Cl2, 88%.
Fig. 4. Keto-mycolic acid 29 and precursors.
In order to obtain the keto-MA without epimerisation, the
protecting group on the meromycolate HO-group was changed to
tetrahydropyanyl and that on the
in Scheme 5. After oxidation and hydrolysis of the ester, the
-silyloxy group could then be deprotected under acidic conditions,
b-hydroxy group to a silyl ether as
b
leaving the stereochemistry adjacent to the ketone unchanged.
Scheme 4. (i) LiHMDS, THF, 47%; (ii) KOOCN]NCOOK, AcOH/MeOH/THF, 75%; (iii) HF-
pyridine, pyridine, THF, 74%; (iv) PCC, CH2Cl2, 83%; (v) LiOH$H2O, MeOH/THF/H2O.
Hydroxy-MA are relatively uncommon, though they have been
observed in some organisms,34 and are thought to be intermediates
in the formation of keto-MA and methoxy-MA.18,35
Deprotection with HF-pyridine and pyridine followed by oxi-
dation gave the protected keto-MA 24 as
a single diaster-
oisomer.32,33 This was fully characterised by 1H and 13C NMR.38 The
MALDI MS showed an [MþNa]þ centred at 1302, matching a major
trans-cyclopropane keto-mycolic acid in M. tuberculosis,39 and
some other mycobacteria,40 and also a major peak in keto-mycolic
acid isolated from Mycobacterium avium.38 Deprotection of this
using lithium hydroxide led to epimerisation adjacent to the ke-
tone. The product 25 showed an ½a D19
þ4.74 (c 0.78, CHCl3), corre-
ꢀ
sponding to an [MD] of 61.6. The contribution to [MD] of the
S-methylketone is known to be þ44, that of the hydroxy acid þ40.
In related systems, the contribution from the methyl-trans-cyclo-
propane unit 7 is ca. þ25.32,33 The observed value of [MD} for 25 is
Scheme 5. (i) Dihydropyran, Hþ, CH2Cl2, 94%; (ii) LiOH$H2O, MeOH/THF/H2O, 45 ꢁC,
90%; (iii) imidazole, DMF, toluene, TBDMSCl, 70 Co, K2CO3, MeOH/THF/H2O, then
KHSO4, 84%; (iv) pyridinium p-toluene sulfonate, MeOH/THF/H2O, 47 Co, 73%; (v) PCC,
CH2Cl2, 88%; (vi) HF-pyridine, pyridine, THF, 84%.

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G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
The product ketone 33 now had an ½a D19
ꢀ
þ10.55 (c 0.54, CHCl3),
acid series in a sample of methoxy-mycolic acid from M. tubercu-
corresponding to an [MD] of þ137, with a predicted value, based on
the figures above, of þ109.
losis.6,39,40 The ½a 2D2
ꢀ
of ꢂ0.97 (CHCl3, 0.468
mmol) corresponded to
an [MD] of ꢂ12.6. The reported contribution to [MD] by the S,S-
a-
In order to prepare a trans-cyclopropane containing methoxy-
MA, the fragment 34 was coupled to sulfone 9 (n¼7) using
LiHMDS, and the resultant alkenes were hydrogenated to provide
the chain extended ester 35. This was converted in four steps into
the sulfone 36 and this in turn was coupled to the aldehyde 37
(prepared from 11 (n¼8)). After saturation of the derived alkenes,
deprotection and oxidation provided the aldehyde 39 (Scheme 6).
methyl-
b
-methoxy-fragment is around ꢂ45,31 so the observed
value is somewhat lower than expected on the basis of additive
contributions.
The trans-cyclopropane mycolic acids described above have al-
ready been found to show interesting biological properties. In ini-
tial ELISA assays to compare the recognition of synthetic mycolic
acids by antibodies in the serum of TB positive patients, the epi-
meric trans-cyclopropane keto-MA 25 gave stronger binding and
somewhat better distinction between TB positive and TB negative
serum samples than related synthetic cis-cyclo-propane keto-MA,
though the response was somewhat lower than that to a mixture
of natural mycolic acids from M. tuberculosis.41 The methoxy-MA 42
gave higher signals in ELISA than the natural mixture, and was
somewhat better at distinguishing TBþ/TBꢂ; related cis-methoxy-
MAs were less effective.41 In studies of mouse pulmonary in-
flammation in response to intratracheal treatments with mycolic
acids, methoxy- and keto-MA containing cis-cyclopropanes caused
solid to mild inflammatory responses, respectively. The trans-cy-
clopropane methoxy-MA 42 partially lost its inflammatory activity
and keto-MA 25 exerted anti-inflammatory alternative activation of
alveolar macrophages and counteracted cis-methoxy-MA induced
airway inflammation.42,43 These differential innate immune activ-
ities may point to a novel means for M. tuberculosis to steer host
immune responses during infection while the anti-inflammatory
property of 25 might be of significance in the therapeutics of in-
flammatory disorders.44 Further studies of these effects are under
way.
Scheme 6. (i) 9 (n¼7), LiHMDS, THF, 81%; (ii) H2, Pd/C, 88%; (iii) LiAlH4, THF, 79%;
(iv) N-bromosuccinimide, PPh3, CH2Cl2, (v) 1-phenyl-1H-tetrazol-5-thiol, K2CO3 (vi)
m-chloroperbenzoic acid, NaHCO3, CH2Cl2, 89%; (vii) LiHMDS, THF, 54%; (viii) KOOCN]
NCOOK, AcOH/MeOH/THF, 97%; (ix) LiAlH4, THF, 72%; (x) PCC, CH2Cl2, 96%.
3. Experimental section
3.1. General
Chemicals used were obtained from commercial suppliers
(Sigma, Aldrich, and Alfa Aeser) or prepared from them by the
methods described. Solvents which were required to be dry, e.g.,
ether, tetrahydrofuran were dried over sodium wire and benzo-
phenone under nitrogen, while dichloromethane and HMPA were
dried over calcium hydride. All reagents and solvents used were of
reagent grade unless otherwise stated. Silica gel (Merck 7736) and
silica gel plates used for column chromatography and thin layer
chromatography were obtained from Aldrich; separated compo-
nents were detected using variously UV light, I2 and phosphomo-
lybdic acid solution in IMS followed by charring. Anhydrous
magnesium sulfate was used to dry organic solutions. Infra-red (IR)
spectra were carried out on a PerkineElmer 1600 FTIR spectrom-
eter as liquid films or KBr disc (solids). Melting points were mea-
sured using a Gallenkamp melting point apparatus. NMR spectra
were carried out on a Bruker AC250 or Advance 400 spectrometer.
The sulfone fragment 40 with the required chain length was
prepared from 18 using a similar method to that described before
for 20 (Supplementary data). Finally, coupling of the 39 and 40
using LiHMDS, followed by hydrogenation of the mixture of alkenes
produced, gave the protected methoxy-MA 41, which could be
deprotected to provide the free acid 42 (Scheme 7).
[a] values were recorded in CHCl3 on a POLAAR 2001 optical ac-
D
tivity polarimeter. Mass spectra were recorded on a Bruker matrix-
assisted laser desorption/ionisation-time of flight mass spectrom-
etry (MALDI-TOF MS) values are given plus sodium to an accuracy
of 2 d.p.
3.1.1. 2,2-Dimethylpropionic acid 8-{(1S,2R)-2-[(S)-3-(tert-butyldi-
phenylsilanyloxy)-1-methylpropyl]cyclopropyl}octyl ester (10, n¼7).
trans-(1S,2R)-2-[(S)-3-(tert-Butyldiphenylsilanyloxy)-1-methyl-
propyl]cyclopropanecarbaldehyde 8,32,33 (2.66 g, 7.00 mmol) in
dry THF (20 mL) was added at room temperature to 2,2-
dimethylpropionic acid 7-(1-phenyl-1H-tetrazol-5-sulphonyl)-
heptyl ester 9 (n¼7) (3.71 g, 9.09 mmol) (see Supplementary data)
in dry THF (30 mL). This solution was cooled to ꢂ12 ꢁC and lithium
bis(trimethylsilyl) amide (12.8 mL, 13.7 mmol, 1.06 M) was added at
Scheme 7. (i) 39, LiHMDS, THF, 28%, (ii) KOOCN]NCOOK, AcOH/MeOH/THF, 94%; (iii)
HF-pyridine, pyridine, THF, 54%; (iv) LiOH$H2O, H2O/THF/MeOH, 69%.
The acid 42 showed all the expected signals in both the proton
and carbon NMR spectra. It gave a mass ion at 1318 (MþNaþ), which
matched a major homologue of the trans-cyclopropane mycolic

G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
6289
between ꢂ12 and ꢂ4 ꢁC. The mixture was allowed to reach rt and
stirred for 2 h, then cooled to 0 ꢁC and quenched with satd aq
ammonium chloride (100 mL). The product was extracted with
petrol/ether (1:1, 3ꢃ50 mL). The combined organic layers were
washed with brine (100 mL), dried and evaporated to give an oil.
Column chromatography eluting with petrol/ether (7:1) gave 2,2-
dimethylpropionic acid 8-{(1R,2R)-2-[(S)-3-(tert-butyldiphenylsi-
lanyloxy)-1-methyl-propyl]cyclopropyl}oct-7-enyl ester (2.79 g,
69%), as a mixture of two isomers in ratio 2.6:1. The alkenes (2.40 g,
4.27 mmol) and 2,4,6-tri-isopropylbenzenesulphonyl hydrazide
(5.11 g, 17.1 mmol) were stirred in dry THF (60 mL) at 40 ꢁC for 18 h.
Further TPBSH (2.61 g, 8.74 mmol) was added and stirred at 50 ꢁC
for 23 h. 1H NMR spectroscopy showed that hydrogenation was
complete. The mixture was diluted with petrol/ether (1:1, 200 mL)
and aq sodium hydroxide solution (100 mL, 2%) was added and the
organic layer was separated. The aqueous layer was re-extracted
with petrol/ether (1:1, 2ꢃ60 mL) and the combined organic
layers were washed with water (50 mL), dried and evaporated.
Column chromatography eluting with petrol/ether (15:1) gave the
(2.9 g, 93%), ½a 2D4
ꢀ
ꢂ5.4 (c 1.01, CHCl3) [Found (MþNa)þ: 689.6622,
C43H90O2SiþNa requires: 689.6602]. This showed dH (500 MHz,
CDCl3): 3.65 (2H, t, J 6.6 Hz), 3.53e3.50 (1H, m), 1.61e1.55 (2H, m),
1.51e1.43 (2H, m), 1.40e1.26 (60H, m, v br), 1.10e1.02 (1H, m), 0.89
(12H, m, including an s), 0.81 (3H, d, J 6.6 Hz), 0.04 (3H, s), 0.03 (3H,
s); dC (126 MHz, CDCl3): 75.9, 63.1, 37.8, 33.6, 32.9, 32.6, 31.9, 30.0,
29.9, 29.7 (v br), 29.68, 29.65, 29.62, 29.6, 29.5, 29.4, 27.7, 26.0, 25.9,
25.8, 22.7, 18.2, 14.4, 14.1, ꢂ4.2, ꢂ4.4; nmax/cmꢂ1: 3332, 2924, 2854,
1465, 1253, 1058.
3.1.4. 5-[(17S,18S)-17-(tert-Butyldimethylsilanyloxy)-18-methyl-hex-
atriacontylsulfonyl]-1-phenyl-1H-tetrazole (13).
(i) N-Bromosuccinimide (0.69 g, 3.90 mmol) was added in por-
tions over 15 min to a stirred solution of alcohol 12 (2.00 g,
2.89 mmol) and triphenylphosphine (0.905 g, 3.45 mmol) in
dichloromethane (30 mL) at 0 ꢁC. The mixture was stirred at
room temperature for 1 h then quenched with satd aq sodium
meta-bisulfate (30 mL). The organic layer was separated and
the aqueous layer was re-extracted with dichloromethane
(2ꢃ30 mL). The combined organic layers were washed with
water, dried and evaporated to give a residue. The residue was
treated with a mixture of petrol/ether (1:1) (50 mL) and heated
at reflux for 30 min, then the triphenylphosphine oxide was
filtered off and washed with petrol/ether (50 mL) and the
filtrate evaporated. Column chromatography eluting
with 10:2 petrol/ether gave a colourless oil, [(1S,2S)-1-(16-
bromohexadecyl)-2-methyleicosyl-oxy]-tert-butyldimethylsi-
title compound as a colourless oil, 10 (n¼7) (2.1 g, 87%), ½a D25
þ7.61
ꢀ
(c 1.31, CHCl3) [Found (MþNa)þ: 587.3886, C36H56O3SiþNa re-
quires: 587.3896]. This showed dH (500 MHz, CDCl3): 7.73e7.69 (4H,
m), 7.46e7.38 (6H, m), 4.10 (2H, t, J 6.6 Hz), 3.80e3.73 (2H, m),
1.80e1.71 (1H, m), 1.66 (2H, br pent, J 6.5 Hz), 1.60e1.55 (1H, m),
1.38e1.22 (20H, br m including s at
(9H, s), 0.98e0.88 (4H, including s at
d
1.24), 1.21e1.15 (1H, m), 1.12
0.93), 0.46e0.40 (1H, m),
d
0.18e0.137 (2H, m), 0.12e0.09 (1H, m); dC (126 MHz, CDCl3): 178.7,
135.6, 134.2, 129.5, 127.5, 64.4, 62.3, 40.2, 38.7, 34.8, 34.3, 29.52,
lane (2.0 g, 91%), ½a D23
ꢀ
ꢂ5.2 (c 1.08, CHCl3) [Found (MþNa)þ:
29.5, 29.2, 28.6, 27.2, 26.9, 25.9, 25.88, 19.8, 19.2, 18.6, 10.6; nmax
:
751.5762, C43H8979BrOSi þ Na requires: 751.5763]. This
showed dH (500 MHz, CDCl3): 3.5 (1H, br, m), 3.42 (2H, t, J
7.0 Hz), 1.87 (2H, br pent, J 6.65 Hz), 1.56e1.20 (63H, m),
2920, 2850, 1730 cmꢂ1
.
3.1.2. 2,2-Dimethylpropionic acid 8-[(1S,2R)-2-((S)-3-hydroxy-1-
methylpropyl)cyclopropyl]-octyl ester (11, n¼7). Tetra-n-buty-
lammonium fluoride (4.78 mL, 4.78 mmol, 1 M in THF) was added
with stirring to ester 10, (n¼7) (1.8 g, 3.2 mmol) in dry THF (30 mL)
at 0 ꢁC under argon. The mixture was allowed to reach room
temperature, stirred for 18 h, diluted with petrol/ethyl acetate (1:1,
100 mL), cooled to 5 ꢁC and quenched with satd aq ammonium
chloride (50 mL). The water layer was re-extracted with petrol/
ethyl acetate (1:1, 2ꢃ30 mL), the combined organic layers were
washed with brine (75 mL), dried and the solvent evaporated.
Column chromatography eluting with petrol/ethyl acetate (5:1,
0.97e0.80 (12H, including s at d 0.89), 0.82 (3H, d, J 6.9 Hz),
0.04 (3H, s), 0.03 (3H, s); dC (126 MHz, CDCl3): 75.8, 37.7, 33.9,
33.5, 32.9, 32.5, 31.9, 30.0, 29.9, 29.73, 29.71, 29.7, 29.65, 29.6,
29.5, 29.4, 28.8, 28.2, 27.7, 26.0, 25.9, 22.7, 18.2, 14.4, 14.1, ꢂ4.2,
ꢂ4.4; nmax: 2929, 2849, 1099, 717 cmꢂ1
.
(ii) The above bromide (1.96 g, 2.69 mmol) was added to a stirred
solution of 1-phenyl-1H-tetrazol-5-thiol (0.530 g, 2.95 mmol)
and potassium carbonate (0.74 g, 5.37 mmol) in acetone
(40 mL) and THF (15 mL) at room temperature. The mixture
was stirred for 18 h, then the solvent was evaporated and the
residue diluted with a mixture of petrol/ether (1:1, 50 mL) and
water (30 mL). The organic layer was separated and the
aqueous layer was extracted with the same solvent mixture
(2ꢃ30 mL). The combined organic layers were dried and
evaporated. Column chromatography eluting with petrol/ether
(5:1) gave a colourless viscous oil, 5-[(17S,18S)-17-(tert-butyl-
dimethyl-silanyloxy)-18-methylhexatriacontyl-sulfanyl]-1-
then 4:1) gave the title compound 11, (n¼7) (0.95 g, 91%), ½a D25
ꢀ
þ16.05 (c 1.19, CHCl3) [Found (MþNa)þ: 349.2717; C20H38O3þNa
requires: 349.2718]. This showed dH (500 MHz, CDCl3): 4.03 (2H, t, J
6.6 Hz), 3.75e3.66 (2H, m), 1.70 (1H, sext., J 7.0 Hz), 1.66 (1H, br
pent, J 6.7 Hz), 1.53 (1H, br sext., J 7.0 Hz), 1.40e1.17 (22H, m, in-
cluding s at d 1.20),1.16e1.1 (1H, m), 0.94 (3H, d, J 6.7 Hz), 0.87e0.80
(1H, m), 0.50e0.44 (1H, m), 0.24e0.12 (3H, m); dC (126 MHz,
CDCl3): 178.7, 64.4, 61.2, 40.3, 38.7, 34.9, 34.3, 29.5, 29.45, 29.4, 29.1,
28.5, 27.2, 25.9, 25.8, 19.8, 18.6, 10.6; nmax: 3363, 2925, 2854,
phenyl-1H-tetrazole (2.11 g, 95%), ½a D22
ꢀ
e4.08 (c 1.25, CHCl3)
[Found (MþNa)þ: 849.6838, C50H94N4OSSiþNa requires:
849.6815]. This showed dH (500 MHz, CDCl3): 7.57e7.52 (5H,
m), 3.52e3.49 (1H, m), 3.4 (2H, t, J 7 Hz), 1.82 (2H, pent, J 7 Hz),
1.57e1.12 (62H, m), 1.09e1.0 (1H, m), 0.96e0.84 (12, including
1731 cmꢂ1
.
3.1.3. (17S,18S)-17-(tert-Butyldimethylsilanyloxy)-18-methyl-hexa-
s at d 0.89), 0.8 (3H, d, J 6.7 Hz), 0.034 (3H, s), 0.025 (3H, s); dC
triacontan-1-ol (12). 2,2-Dimethylpropionic acid (17S,18S)-17-
(126 MHz, CDCl3): 154.4, 133.8, 129.9, 129.7, 123.7, 75.8, 37.7,
33.5, 33.3, 32.5, 31.9, 30.0, 29.8, 29.7, 29.5, 29.4, 29.3, 29.1, 29,
(tert-butyldimethyl-silanyloxy)-18-methylhexatriacontyl
ester
(3.50 g, 4.66 mmol) (see Supplementary data) in dry THF (10 mL)
was added dropwise over 15 min to a suspension of lithium alu-
minium hydride (0.265 g, 6.99 mmol) in THF (25 mL) at 0 ꢁC under
nitrogen. The mixture was allowed to reach room temperature,
heated to reflux for 1 h, then quenched with satd aq sodium sulfate
decahydrate at 0 ꢁC until a white precipitate had formed. THF
(50 mL) was added and the mixture was stirred at room tempera-
ture for 30 min, filtered through a bed of silica and the solvent
evaporated. Column chromatography eluting with petrol/ethyl
acetate (10:1) gave the title compound as a colourless oil, 12
28.6, 27.7, 25.9, 25.88, 22.6, 18.1, 14.4, 14.1, ꢂ4.2, ꢂ4.5; nmax
:
2928, 2861, 1097 cmꢂ1
.
(iii) Ammonium heptamolybdate(VI) tetrahydrate (1.5 g, 1.2 mmol)
in ice cold aq hydrogen peroxide (35% w/w, 15 mL) was added
dropwise to a stirred solution of the tetrazole (2.00 g,
2.42 mmol) in a mixture of methylated spirit (30 mL) and
tetrahydrofuran (30 mL) at 5 ꢁC. The resulting yellow solution
was stirred for 1 h at room temperature, then further ice cold
ammonium heptamolybdate(VI) tetrahydrate (1.5 g, 1.2 mmol)

6290
G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
in hydrogen peroxide (15 mL) was added. The mixture was
(2ꢃ30 mL). The combined organic layers were dried and
evaporated. The procedure was repeated for another 16 h.
Column chromatography eluting with petrol/ether (30:1)
stirred at room temperature for 16 h, then dichloromethane
(60 mL) was added followed by water (200 mL). The organic
layer was separated and the aqueous layer was re-extracted
with dichloromethane (2ꢃ30 mL). The combined organic
layers were washed with water, dried and evaporated to give
a residue. Column chromatography eluting with petrol/ether
(5:2) gave a white solid, the title compound 13 (1.7 g, 82%),
then gave
a colourless oil, 2,2-dimethylpropionic acid
8-{(1S,2R)-2-[(1S,20S,21S)-20-(tert-butyldimethylsilanyloxy)-
1,21-dimethylnonatriacontyl]cyclopropyl}octyl ester (1.05 g,
75%), ½a 2D3
ꢀ
ꢂ1.3 (c 0.93, CHCl3) [Found (MþNa)þ: 981.9379,
C63H126O3SiþNa requires: 981.9373]. This showed dH
½
a 2D2
ꢀ
e3.74 (c 1.15, CHCl3) [Found (MþNa)þ: 881.6722,
(500 MHz, CDCl3): 4.05 (2H, t, J 6.6 Hz), 3.52e3.49 (1H, m), 1.63
C50H94N4O3SSiþNa requires: 881.6713]. This showed dH
(500 MHz, CDCl3): 7.73e7.71 (2H, m), 7.65e7.61 (3H, m), 3.74
(2H, distorted t, J 7.85 Hz), 3.5 (1H, br, sextet, J 3.43 Hz), 1.96
(2H, br pent, J 7.6 Hz), 1.5 (2H, pent, J 7.55 Hz), 1.4e1.15 (60H,
(2H, br pent, J 6.6 Hz), 1.55e1.16 (82H, br m and s at d 1.21 for
9H), 1.08e1.01 (1H, m), 0.91e0.88 (15H, m, including s and t, J
6.6 Hz), 0.80 (3H, d, J7.0 Hz), 0.71e0.64 (1H, m), 0.48e0.42 (1H,
m), 0.22e0.09 (3H, m), 0.04 (3H, s), 0.03 (3H, s); dC (126 MHz,
CDCl3): 178.6, 75.9, 64.5, 38.7, 38.1, 37.7, 37.4, 34.5, 33.5, 32.5,
31.9, 30.1, 30.0, 29.9, 29.72, 29.7 (v br), 29.66, 29.60, 29.56,
29.49, 29.4, 29.3, 28.6, 27.7, 27.3, 27.2, 26.1, 26.0, 25.9, 22.7, 19.7,
18.6, 18.2, 14.4, 14.1, 10.5, ꢂ4.2, ꢂ4.4; nmax: 2924, 2853, 1733,
m), 1.06e1.01 (1H, m), 0.9e0.87 (12H, including s at d 0.89), 0.8
(3H, d, J 6.65 Hz), 0.04 (3H, s), 0.03 (3H, s); dC (126 MHz, CDCl3):
153.5, 133.1, 131.4, 129.7, 125.1, 75.9, 56, 37.7, 33.5, 32.5, 31.9,
30.0, 29.9, 29.7, 29.65, 29.6, 29.5, 29.4, 29.2, 28.9, 28.1, 27.7,
25.96, 25.9, 22.7, 21.9, 18.2, 14.4, 14.1, ꢂ4.2, ꢂ4.4; nmax: 2924,
1464, 1284, 1253, 1154, 1075 cmꢂ1
.
2849, 1343, 1157, 1096 cmꢂ1
.
(ii) The above ester (0.80 g, 0.83 mmol) in dry THF (5 mL) was
added dropwise over 15 min to a suspension of lithium alu-
minium hydride (0.063 g, 1.67 mmol) in THF (5 mL) at 0 ꢁC
under nitrogen. The mixture was allowed to reach room tem-
perature, heated at reflux for 1 h, then satd aq sodium sulfate
decahydrate was added at 0 ꢁC until a white precipitate had
formed. THF (20 mL) was added and the mixture was stirred at
room temperature for 30 min, filtered through a bed of silica
and the solvent evaporated. Column chromatography eluting
with 5:2 petrol/ether gave the title compound as a colourless
3.1.5. 2,2-Dimethylpropionic acid 8-[(1S,2R)-2-((S)-1-methyl-3-
oxopropyl)cyclopropyl]octyl ester (14). A solution of alcohol 11
(n¼7) (0.9 g, 2.8 mmol) in dichloromethane (10 mL) was added to
a stirred suspension of PCC (1.78 g, 8.28 mmol) in dichloromethane
(50 mL). The mixture was stirred for 2 h at room temperature then
diluted with ether (250 mL), filtered through a bed of silica and the
solvent was evaporated. Column chromatography eluting with
petrol/ether (3:1) gave the title compound as a colourless oil, 14
oil, 15 (0.6 g, 82%), ½a D25
ꢀ
ꢂ0.64 (c 1.4, CHCl3) [Found (MþNa)þ:
(0.81 g, 91%), ½a D25
ꢀ
þ22.5 (c 1.42, CHCl3) [Found (MþNa)þ: 347.2535,
897.8788, C58H118O2SiþNa requires: 897.8798]. This showed dH
(500 MHz, CDCl3): 3.65 (2H, t, J 6.6 Hz), 3.52e3.49 (1H, m),
1.60e1.54 (2H, m), 1.48e1.16 (82H, m, v br), 1.08e1.01 (1H, m),
0.93e0.88 (15H, m, including s for the tert-butyl), 0.80 (3H, d, J
6.6 Hz), 0.71e0.64 (1H, m), 0.48e0.43 (1H, m), 0.21e0.09 (3H,
m), 0.04 (3H, s), 0.03 (3H, s); dC (126 MHz, CDCl3): 75.9, 63.1,
38.1, 37.7, 37.4, 34.5, 33.6, 32.8, 32.5, 31.9, 30.1, 30.0, 29.9, 29.74,
29.72, 29.69, 29.67, 29.66, 29.64, 29.5, 29.4, 27.7, 27.3, 26.1, 26.0,
C20H36O3þNa requires: 347.2562]. This showed dH (500 MHz,
CDCl3): 9.8 (1H, t, J 2.5 Hz), 4.04 (2H, t, J 6.6 Hz), 2.52 (1H, ddd, J 2.5,
6.0, 15.8 Hz), 2.39 (1H, ddd, J 2.5, 7.6, 15.8 Hz), 1.61 (2H, pent,
6.6 Hz), 1.34e1.26 (12H, m), 1.19 (9H, s), 1.16e1.12 (1H, m), 1.02 (3H,
d, J 6.6 Hz), 0.51e0.45 (1H, m), 0.34e0.18 (3H, m); dC (126 MHz,
CDCl3): 202.9, 178.6, 64.4, 51.4, 34.0, 33.9, 29.5 29.46, 29.4, 29.2,
28.6, 27.2, 25.9, 25.6, 19.9, 18.8, 11.4; nmax: 2922, 2853, 1729 cmꢂ1
.
25.9, 25.8, 22.7, 19.7, 18.6, 18.2, 14.4, 14.1, 10.5, ꢂ4.2, ꢂ4.4; nmax
:
3.1.6. 8-{(1S,2R)-2-[(1S,20S,21S)-20-(tert-Butyldimethylsilanyloxy)-
1,21-dimethylnonatriacontyl]-cyclopropyl}-octan-1-ol (15).
(i) Aldehyde 14 (0.73 g, 2.25 mmol) was dissolved in dry THF
(15 mL) and a solution of 5-[(17S,18S)-17-(tert-butyldimethyl-
silanyloxy)-18-methylhexatriacontylsulfonyl]-1-phenyl-1H-
tetrazole 13 (1.93 g, 2.25 mmol) in dry THF (20 mL) was added
at room temperature. This solution was cooled to ꢂ12 ꢁC and
lithium bis(trimethylsilyl)amide (3.57 mL, 3.37 mmol, 1.06 M)
was added at between ꢂ12 and ꢂ4 ꢁC. The solution was
allowed to reach room temperature and stirred for 2 h. Petrol/
ether (1:1, 100 mL) and satd aq ammonium chloride (30 mL)
were added. The organic phase was separated and water layer
was extracted with petrol/ether (1:1, 2ꢃ75 mL). The combined
organic layers were dried and the solvent was evaporated. The
product was purified by column chromatography eluting with
3332, 2924, 2853, 1464, 1253, 1058 cmꢂ1
.
3.1.7. 8-{(1S,2R)-2-[(1S,20S,21S)-20-(tert-Butyldimethylsilanyloxy)-
1,21-dimethylnonatriacontyl]-cyclopropyl}octanal (16). A solution of
alcohol 15 (0.43 g, 0.49 mmol) in dichloromethane (10 mL) was
added to a stirred suspension of PCC (0.32 g, 1.47 mmol) in
dichloromethane (10 mL). After 2 h at room temperature, it was
diluted with ether (20 mL), filtered through a bed of silica and the
solvent was evaporated. Column chromatography eluting with
petrol/ether (10:1) gave the title compound as a colourless oil, 16
(0.37 g, 86%), ½a D25
ꢀ
ꢂ0.71 (c 0.52, CHCl3) [Found (MþNa)þ: 895.8627,
C58H116O2SiþNa requires: 895.8637]. This showed dH (500 MHz,
CDCl3): 9.77 (1H, t, J 1.9 Hz), 3.52e3.49 (1H, m), 2.43 (2H, dt, J 1.9,
7.3 Hz), 1.64 (2H, br pent, J 7.3 Hz), 1.58e1.01 (81H, m, v br),
0.91e0.88 (15H, m, including s and t, J 7.3 Hz), 0.80 (3H, d, J 7.0 Hz),
0.70e0.65 (1H, m), 0.47e0.43 (1H, m), 0.22e0.09 (3H, m), 0.04 (3H,
s), 0.03 (3H, s); dC (126 MHz, CDCl3): 202.9, 75.9, 43.9, 38.1, 37.7,
37.4, 34.4, 33.5, 32.5, 31.9, 30.1, 30.0, 29.9, 29.72, 29.70 (v br), 29.65,
29.60, 29.5, 29.4, 29.35, 29.3, 29.2, 27.7, 27.3, 26.1, 26.0, 25.9, 22.7,
22.1, 19.7, 18.6, 18.2, 14.4, 14.1, 10.5, ꢂ4.2, ꢂ4.4; nmax: 2925, 2854,
petrol/ether (30:1) to give
a colourless oil, (E/Z)-2,2-
dimethylpropionic acid 8-{(1S,2R)-2-[(1S,20S,21S)-20-(tert-
butyl-dimethylsilanyloxy)-1,21-dimethylnonatriacont-3-
enyl]-cyclopropyl}octyl ester (1.5 g, 70%) as a mixture of two
isomers in ratio 3:1. Dipotassium azodicarboxylate (3.9 g,
2.0 mmol) was added to a stirred solution of the above alkene
(1.40 g, 1.46 mmol) in dry THF (15 mL) and methanol (3 mL) at
1731, 1465, 1375, 1253, 1076 cmꢂ1
.
ꢁ
10 C under nitrogen, resulting in a yellow suspension. Acetic
acid (3 mL) in THF (3 mL) was added dropwise over 8 h, after
which a white precipitate had formed. The mixture was stirred
for 16 h then slowly poured into satd aq NaHCO3 (50 mL). The
product was extracted with petrol/ether (20:1) (30 mL) and
the aqueous layer was re-extracted with petrol/ether (20:1)
3.1.8. (R)-2-[(R)-9-Bromo-1-(tert-butyldimethylsilanyloxy)non-3-
enyl]hexacosanoic acid methyl ester (19). Lithium bis(trimethylsilyl)
amide (9.38 mL, 9.95 mmol, 1.06 M) was added to a stirred solution
of
(R)-2-[(R)-1-(tert-butyldimethylsilanyloxy)-3-oxopropyl]hex-
acosanoic acid methyl ester (18)37 (2.90 g, 4.87 mmol) and 5-(6-

G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
6291
bromohexane-1-sulfonyl)-1-phenyl-1H-tetrazole (17)31 (2.85 g,
7.65 mmol) in dry THF (100 mL) at ꢂ12 ꢁC under nitrogen. The
reaction was stirred at room temperature for 3 h then quenched by
addition of satd aq ammonium chloride (100 mL), extracted with
petrol/ether (1:1, 3ꢃ150 mL), dried and the solvent was evaporated.
Column chromatography eluting with petrol/ether (20:1) gave
a colourless oil, (R)-2-[(E/Z)-(R)-9-bromo-1-(tert-butyldimethylsi-
lanyloxy)-non-3-enyl]hexacosanoic acid methyl ester (3.41 g, 94%),
as a mixture of two isomers in ratio 2:1. Palladium (10% on carbon,
0.6 g) was added to a stirred solution of the above alkene (3.41 g,
4.58 mmol) in THF (40 mL) and ethanol (40 mL). Hydrogenation
was carried out for 16 h. The solution was filtered over a bed of
Celite and the solvent was evaporated. Column chromatography
eluting with petrol/ether (20:1) gave the title compound 19 as
br pent, J 3.8 Hz), 3.40 (2H, t, J 7.6 Hz), 2.44 (1H, dt, J 5.4, 9.1 Hz),
1.97e1.88 (2H, v br m), 1.82 (2H, quintet, J 7.6 Hz), 1.75e1.67
(1H, m), 1.63e1.56 (1H, m), 1.46e1.39 (5H, m), 1.38e1.10 (50H,
br m), 0.89 (3H, t, J 7.0 Hz); dC (126 MHz, CDCl3): 176.2, 154.5,
133.8, 130.0, 129.7, 123.8, 72.2, 51.4, 50.0, 35.6, 33.3, 31.9, 29.7,
29.6, 29.5, 29.48, 29.40, 29.37, 29.3, 29.31, 29.0, 28.9, 28.6, 27.4,
25.7, 22.7, 14.1; nmax: 3494, 2921, 1720, 1596, 1500, 1464, 1378,
1300, 1278, 1239, 1190, 1131, 1077 cmꢂ1
.
(iii) A mixture of acetic anhydride (11 mL) and anhydrous pyridine
(11 mL) was added to stirred solution of the above ester (0.75 g,
1.03 mmol) in dry toluene (30 mL) at room temperature and
the mixture was stirred for 18 h, diluted with toluene (20 mL)
and the solvent was evaporated under reduced pressure
to give a solid. This was purified by column chromatography
eluting with petrol/ether (5:1) to give a white solid, (R)-2-
[(R)-1-acetoxy-9-(5-phenyl-5H-tetrazol-1-ylsulfanyl)nonyl]
a colourless oil (1.23 g, 36%), ½a D26
ꢀ
e2.1 (c 1.35, CHCl3) [Found
(MþNa)þ: 767.5372 C42H8579BrO3Si þ Na requires: 767.5344]. This
showed dH (500 MHz, CDCl3): 3.93e3.89 (1H, m), 3.66 (3H, s), 3.41
(2H, t, J 7.0 Hz), 2.53 (1H, ddd, J 3.8, 7.3, 10.7 Hz), 1.86 (2H, quintet, J
hexacosanoic acid methyl ester (0.66 g, 84%), ½a D17
þ7.2 (c 0.47,
ꢀ
CHCl3), mp 42e44 ꢁC [Found (MþNa)þ: 793.5647,
C45H78N4O4SþNa requires: 793.5636]. This showed dH
(500 MHz, CDCl3): 7.60e7.52 (5H, m), 5.08 (1H, ddd, J 3.8, 7.0,
10.8 Hz), 3.67 (3H, s), 3.39 (2H, t, J 7.3 Hz), 2.61 (1H, ddd, J 4.1,
6.6, 10.7 Hz), 2.02 (3H, s), 1.81 (2H, quintet, J 7.6 Hz), 1.67e1.48
(4H, br m), 1.43 (3H, br pent, J 7.3 Hz), 1.35e1.10 (51H, br m),
0.88 (3H, t, J 7.0 Hz); dC (126 MHz, CDCl3): 173.6, 170.3, 154.4,
133.8, 130.0, 129.7, 123.8, 74.0, 51.5, 49.6, 41.3, 34.1, 33.3, 31.9,
31.7, 29.7 (v br), 29.5, 29.4, 29.4, 29.31, 29.3, 29.2, 29.0, 28.9,
28.5, 28.1, 27.4, 24.9, 22.6, 22.3, 21.0, 14.1; nmax: 2918, 2850,
7.0 Hz), 1.60e1.54 (5H, m including s at
1.33e1.12 (47H, m), 0.91e0.83 (12H, including t at
and s at
d
1.55), 1.52e1.38 (6H, m),
d
0.89, J 6.9 Hz
d
0.87), 0.00 (3H, s), ꢂ0.02 (3H, s), dC (126 MHz, CDCl3):
175.0, 73.15, 51.58, 51.19, 34.7, 33.9, 33.6, 32.8, 31.9, 29.7 (v br),
29.65, 29.6, 29.4, 28.7, 28.1, 27.8, 27.5, 25.7, 23.7, 22.7, 18.0, 14.1,
ꢂ4.4, ꢂ4.9; nmax: 2925, 2854, 1741, 1464, 1436, 1361, 1254, 1195,
1167, 1062, 1006, 939, 836, 813, 776, 722, 665 cmꢂ1
.
3.1.9. (R)-2-[(R)-1-Acetoxy-9-(5-phenyl-5H-tetrazol-1-sulfonyl)-
nonyl]hexacosanoic acid methyl ester (20).
1743, 1597, 1500, 1468, 1435, 1385, 1239, 1166, 1074, 1018 cmꢂ1
.
(i) 1-Phenyl-1H-tetrazole-5-thiol (0.30 g, 1.69 mmol), methyl es-
ter 19 (1.20 g, 1.61 mmol), anhydrous potassium carbonate
(0.47 g, 3.38 mmol) and acetone (50 mL) were vigorously
stirred for 18 h at room temperature. Water (100 mL) was
added and the mixture was extracted with dichloromethane
(150 mL, 2ꢃ100 mL). The combined organic phases were
washed with brine (2ꢃ100 mL), dried and the solvent was
evaporated. Column chromatography eluting with 4:1 petrol/
ether gave a colourless oil, (R)-2-[(R)-1-(tert-butyldimethylsi-
lanyloxy)-9-(5-phenyl-5H-tetrazol-1-ylsulfanyl)-nonyl]hex-
(iv) m-Chloroperbenzoic acid (0.54 g, 1.56 mmol) in dichloro-
methane (20 mL) was added at 0 ꢁC to a solution of the above
ester (0.60 g, 0.78 mmol) and NaHCO3 (0.29 g, 3.51 mmol) in
dichloromethane (15 mL) and stirred at room temperature for
20 h. The mixture was quenched by addition of satd aq NaHCO3
(20 mL) and extracted with dichloromethane (80 mL,
3ꢃ30 mL). The combined organic phases were washed with
water (80 mL), dried and evaporated. Column chromatography
eluting with petrol/ether (5:1) gave the title compound as
acosanoic acid methyl ester (1.08 g, 79%), ½a D26
ꢀ
e3.5 (c 0.65,
a white solid 20 (0.55 g, 88%), ½a D23
þ9.0 (c 0.78, CHCl3) [Found
ꢀ
CHCl3) [Found (MþNa)þ: 865.6393, C49H90N4O3SSiþNa re-
quires: 865.6395]. This showed dH (500 MHz, CDCl3): 7.61e7.52
(5H, m), 3.89e3.86 (1H, m), 3.63 (3H, s), 3.38 (2H, t, J 7.3 Hz),
2.50 (1H, ddd, J 3.8, 7.3, 10.7 Hz), 1.80 (2H, quintet, J 7.6 Hz),
1.62e1.58 (1H, v br s), 1.55e1.34 (6H, m), 1.33e1.07 (51H, br m),
(MþNa)þ: 825.5552, C45H78N4O6SþNa requires: 825.5534].
This showed dH (500 MHz, CDCl3): 7.72e7.68 (2H, m),
7.66e7.58 (3H, m), 5.09 (1H, ddd, J 4.1, 7.3, 10.7 Hz), 3.73 (2H,
distorted t, J 7.0 Hz), 2.61 (1H, ddd, J 4.1, 6.6, 10.7 Hz), 2.04 (3H,
s), 1.95 (2H, br quintet, J 7.9 Hz), 1.68e1.57 (3H, m), 1.56e1.41
(4H, m), 1.39e1.08 (54H, br m), 0.89 (3H, t, J 7.0 Hz); dC
(126 MHz, CDCl3): 173.6, 170.4, 153.5, 133.0, 131.4, 129.7, 125.1,
74.0, 56.0, 51.5, 49.6, 31.9, 13.7, 29.7 (v br), 29.6, 29.54, 29.5,
29.4, 29.3, 29.2, 29.0, 28.8, 28.11, 28.05, 27.5, 25.0, 22.7, 21.9,
21.0, 14.1; nmax: 3449, 2923, 1732, 1594, 1499, 1463, 1377, 1341,
0.96e0.79 (12H, m including t at d 0.86, J 6.3 Hz and s at d 0.84),
0.02 (3H, s), 0.00 (3H, s); dC (126 MHz, CDCl3): 175.0, 154.5,
133.8, 130.0, 129.7, 123.8, 73.2, 51.6, 51.2, 33.6, 33.4, 31.9, 29.7,
29.6, 29.58, 29.4, 29.38, 29.3, 29.1, 29.0, 28.6, 27.7, 27.4, 25.7,
22.7, 22.6, 18.0, 14.1, ꢂ4.4, ꢂ4.9; nmax: 2929, 2854, 1739, 1501,
1464, 1278, 1195, 1073, 836, 760, 694 cmꢂ1
.
1244, 1152, 1017, 961 cmꢂ1
.
(ii) The above methyl ester (1.08 g, 1.28 mmol) was stirred in dry
THF (20 mL) in a dry polyethylene vial under argon at room
temperature. Pyridine (0.4 mL, 1.3 mmol) and HF$Pyridine
(1.5 mL) was added and the mixture was stirred for 17 h at
45 ꢁC. The reaction was diluted with petrol/ether (1:1, 100 mL)
and neutralized with satd aq NaHCO3 until no more carbon
dioxide was liberated. The mixture was separated and the
aqueous layer was re-extracted with petrol/ether (1:1,
2ꢃ100 mL). The combined organic layers were washed with
brine and dried and the solvent was evaporated. Column
chromatography eluting with petrol/ether (5:2) gave a white
3.1.10. (R)-2-((R)-1-Acetoxy-17-{(1S,2R)-2-[(1S,20S,21S)-20-(tert-
butyldimethylsilanyloxy)-1,21-dimethyl-nonatriacontyl]cyclopropyl}
heptadecyl)hexacosnoic acid methyl ester (21). Ester 20 (0.40 g,
0.50 mmol) was dissolved in dry THF (10 mL) and a solution of 8-
{(1S,2R)-2-[(1S,20S,21S)-20-(tert-butyl-dimethylsilanyloxy)-1,21-
dimethyl-nonatriacontyl]cyclopropyl}-octanal (16) (0.30 g, 0.34
mmol) in dry THF (10 mL) was added at room temperature. This
solution was cooled to ꢂ12 ꢁC and lithium bis(trimethylsilyl)amide
(0.80 mL, 0.85 mmol, 1.06 M) was added. The solution was allowed
to reach room temperature and stirred for 2 h. Ether (25 mL) and
satd aq ammonium chloride (30 mL) were added. The organic
phase was separated and the aq layer was extracted with petrol/
ether (20:1, 2ꢃ40 mL). The combined organic layers were dried and
solid,
(R)-2-[(R)-1-hydroxy-9-(5-phenyl-5H-tetrazol-1-
ylsulfanyl)nonyl]hexacosanoic acid methyl ester (0.93 g, 81%),
½
a 1D7
ꢀ
þ7.7 (c 0.50, CHCl3), mp 76e78 ꢁC [Found (MþNa)þ:
751.5530, C43H76N4O3SþNa requires: 751.5530]. This showed
dH (500 MHz, CDCl3): 7.61e7.52 (5H, m), 3.72 (3H, s), 3.65 (1H,

6292
G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
the solvent was evaporated. Column chromatography eluting with
petrol/ether (20:1) gave a colourless oil, (R)-2-((E/Z)-(R)-1-acetoxy-
17-{(1S,2R)-2-[(1S,20S,21S)-20-(tert-butyldimethyl-silanyloxy)-
1,21-dimethylnonatriacontyl]cyclopropyl}heptadec-9-enyl)hexa-
cosnoic acid methyl ester (0.23 g, 47%) as a mixture of two isomers
in ratio 2.6:1. Dipotassium azodicarboxylate (2.0 g, 10.3 mmol) was
added to a stirred solution of the alkenes (200 mg, 0.14 mmol) in
THF (10 mL) and methanol (2 mL) at 5 ꢁC. Half of a solution of glacial
acetic acid (5 mL) and THF (2 mL) was added dropwise at 5 ꢁC and
the mixture was stirred at room temperature for 2 h. The other half
of the glacial acetic acid solution was then added and the mixture
was stirred overnight. Further dipotassium azodicarboxylate (2.0 g)
and glacial acetic acid (2 mL) were added and stirred overnight.
This mixture was added slowly to satd aq ammonium chloride and
extracted with petrol/ether (1:1, 3ꢃ80 mL) and the combined or-
ganic layers were washed with water (50 mL) and the solvent was
evaporated. The procedure was repeated. Column chromatography
eluting with petrol/ether (20:1) gave the title compound as a white
(5:2, 4ꢃ20 mL). The combined organic layers were washed with
water (10 mL), dried and the solvent evaporated. Column chro-
matography eluting with 3:1 petrol/ethyl acetate gave the title
compound as a white solid, 23 (18 mg, 58%), ½a D16
ꢂ1.04 (c 0.54,
ꢀ
CHCl3), mp 51e53 ꢁC [Found (MþNa)þ: 1304.3184, C87H172O4þNa
requires: 1304.3153]. This showed dH (500 MHz, CDCl3): 3.73e3.69
(1H, m), 3.53e3.50 (1H, m), 2.46 (1H, dt, J 8.8, 5.4 Hz), 1.75e1.59
(1H, m), 1.55e1.12 (148H, m, v br), 0.91e0.86 (12H, m), 0.69e0.63
(1H, m), 0.48e0.42 (1H, m), 0.22e0.08 (3H, m); dC (126 MHz,
CDCl3): 178.8, 75.4, 72.1, 50.7, 38.2, 38.1, 37.4, 35.6, 34.5, 34.4, 33.3,
31.9, 30.1, 30.0, 29.73, 29.71 (v br), 29.66, 29.60, 29.54, 29.43, 29.36,
27.4, 27.3, 27.2, 26.3, 26.1, 25.7, 22.7, 19.7, 18.6, 14.1, 13.6, 10.5; nmax
:
3331, 2920, 2851, 1686, 1460, 1377, 1201 cmꢂ1
.
3.1.13. (R)-2-{(R)-17-[(1S,2R)-2-((1S,21S)-1,21-Dimethyl-20-
oxononatriacontyl)-cyclopropyl]-1-hydroxyheptadecyl}-hex-
acosanoic acid methyl ester (24). The ester 22 (60 mg, 0.045 mmol)
was dissolved in dichloromethane (3 mL) and added in portions to
a stirred solution of PCC (29 mg, 0.134 mmol) in dichloromethane
(10 mL) at room temperature. The mixture was stirred for 3 h then
diluted with ether (20 mL) and filtered through a bed of silica, and
the solvent was evaporated. Column chromatography eluting with
5:1 petrol/ether gave the title compound as a white solid 24 (50 mþg,
solid, 21 (150 mg, 75%), ½a D13
ꢀ
þ2.08 (c 0.64, CHCl3) [Found (MþNa)þ:
1474.4282, C96H190O5SiþNa requires: 1474.4280]. This showed dH
(500 MHz, CDCl3): 5.10 (1H, ddd, J 4.2, 6.9, 8.1 Hz), 3.69 (3H, s),
3.52e3.49 (1H, m), 2.62 (1H, ddd, J 4.2, 7.0, 10.7 Hz), 2.04 (3H, s),
1.68e1.16 (148H, m, v br), 1.09e1.02 (1H, m), 0.91e0.88 (18H, m,
including s), 0.80 (3H, d, J 6.6 Hz), 0.70e0.65 (1H, m), 0.49e0.43
(1H, m), 0.23e0.09 (3H, m), 0.04 (3H, s), 0.03 (3H, s); dC (126 MHz,
CDCl3): 173.6, 170.3, 75.9, 74.1, 51.5, 49.6, 38.1, 37.8, 37.4, 34.5, 33.6,
32.5, 31.9, 31.7, 30.1, 30.0, 29.9, 29.74, 29.72 (v br), 29.67, 29.64,
29.59, 29.57, 29.49, 29.47, 29.45, 29.41, 29.37, 28.1, 27.7, 27.5, 27.3,
26.2, 26.0, 25.9, 25.0, 22.7, 21.0, 19.7, 18.6, 18.2, 14.4, 14.1, 10.5, ꢂ4.2,
83%), ½a 2D1
ꢀ
þ9.12 (c 0.83, CHCl3), mp 32e33 ꢁC [Found (MþNa) :
1358.3206, C90H174O5þNa requires: 1358.3253]. This showed dH
(500 MHz, CDCl3): 5.10 (1H, br dt, J 4.0, 8.1 Hz), 3.69 (3H, s), 2.62
(1H, ddd, J 4.4, 7.0, 10.7 Hz), 2.51 (1H, sext, J 6.7 Hz), 2.43 (1H, dt, J
14.6, 7.6 Hz), 2.40 (1H, dt, J 14.6, 7.6 Hz), 2.03 (3H, s), 1.65e1.17
(146H, m, v br),1.05 (3H, d, J 7.0 Hz), 0.90 (3H, d, J 7.0 Hz), 0.89 (6H, t,
J 6.8 Hz), 0.70e0.65 (1H, m), 0.48e0.42 (1H, m), 0.22e0.09 (3H, m);
dC (126 MHz, CDCl3): 215.1, 173.6, 170.3, 74.1, 51.5, 49.6, 46.3, 41.1,
38.1, 37.4, 34.5, 33.0, 31.9, 31.7, 30.1, 29.72, 29.70 (v br), 29.67, 29.65,
29.60, 29.57, 29.55, 29.51, 29.48, 29.46, 29.44, 29.39, 29.35, 28.1,
27.5, 27.4, 27.3, 26.1, 25.0, 23.7, 22.7, 21.0, 19.7, 18.6, 16.4, 14.1, 10.5;
ꢂ4.4; nmax: 2925, 2853, 1746, 1465, 1372, 1248, 1023 cmꢂ1
.
3.1.11. (R)-2-((R)-1-Acetoxy-17-{(1S,2R)-2-[(1S,20S,21S)-20-
hydroxy-1,21-dimethylnonatriacontyl]-cyclopropyl}-heptadecyl)-
hexacosnoic acid methyl ester (22). The ester 21 (0.140 g,
0.096 mmol) was stirred in dry THF (9.0 mL) in a dry polyethylene
vial under argon at room temperature. Pyridine (0.2 mL) and
HF$pyridine (1.3 mL) were added and the mixture was stirred for
17 h at 45 ꢁC, then diluted with petrol/ether (1:1, 10 mL) and
neutralized with satd aq NaHCO3 until no more carbon dioxide was
liberated. The mixture was extracted and the aqueous layer was re-
extracted with petrol/ether (1:1, 2ꢃ50 mL). The combined organic
layers were washed with brine and dried, and the solvent was
evaporated. Column chromatography eluting with petrol/ether
nmax: 2919, 2850, 1737, 1703, 1471, 1375, 1241, 1162 cmꢂ1
.
3.1.14. (R)-2-{(R)-17-[(1S,2R)-2-((1S,21RS)-1,21-Dimethyl-20-oxo-
nonatriacontyl)-cyclopropyl]-1-hydroxy-heptadecyl}-hexacosanoic
acid (25). Lithium hydroxide monohydrate (45.2 mg, 1.08 mmol)
was added to a stirred solution of the ester 24 (48 mg, 0.036 mmol)
in THF (5 mL), methanol (0.2 mL) and water (0.2 mL) at room tem-
perature. The mixture was stirred at 45 ꢁC for 18 h, cooled to room
temperature and diluted with petrol/ethyl acetate (5:2, 10 mL) then
acidified to pH 1 by dropwise addition of 5% aq HCl. Further petrol/
ethyl acetate (5:2, 30 mL) was added and extracted. The aqueous
layer was re-extracted with petrol/ethyl acetate (5:2, 4ꢃ30 mL). The
combined organic layers were washed with water (20 mL), dried and
the solvent was evaporated. The product was purified by column
chromatography eluting with petrol/ethyl acetate (7:2) to give the
(5:1) gave the title compound as a white solid 22 (95 mg, 74%), ½a D21
ꢀ
ꢂ0.81 (c 0.74, CHCl3), mp 43e44 ꢁC [Found (MþNa)þ: 1360.3449,
C90H176O5þNa requires: 1360.3415]. This showed dH (500 MHz,
CDCl3): 5.09 (1H, ddd, J 4.4, 6.9, 8.2 Hz), 3.68 (3H, s), 3.52e3.49 (1H,
m), 2.62 (1H, ddd, J 4.4, 6.9, 10.7 Hz), 2.04 (3H, s), 1.67e1.14 (150H,
m, v br), 0.90 (3H, d, J 6.6 Hz), 0.89 (3H, t, J 6.9 Hz), 0.86 (3H, d, J
6.9 Hz), 0.71e0.64 (1H, m), 0.48e0.42 (1H, m), 0.22e0.09 (3H, m);
dC (126 MHz, CDCl3): 173.6, 170.3, 75.2, 74.1, 51.5, 49.6, 38.2, 38.1,
37.4, 34.51, 34.49, 33.4, 31.9, 31.7, 30.1, 30.0, 29.72, 29.7 (v br), 29.65,
29.6, 29 5, 29 4, 29.39, 29.36, 28.1, 27.5, 27.4, 27.3, 26.3, 16.1, 25.0,
22.7, 21.0, 19.7, 18.6, 14.1, 13.6, 10.5; nmax: 3489, 2850, 1739, 1470,
title compound as a white solid, 25 (37 mg, 79%), ½a D19
þ4.74 (c 0.78,
ꢀ
CHCl3), mp 66e68 ꢁC [Found (MþNa)þ: 1302.2935, C87H170O4þNa
requires: 1302.2991]. This showed dH (500 MHz, CDCl3): 3.74e3.70
(1H, m), 2.51 (1H, sext, J 6.9 Hz), 2.46 (1H, dt, J 8.8, 5.4 Hz), 2.43 (1H,
dt, J 14.8, 7.3 Hz), 2.40 (1H, dt, J 14.8, 7.3 Hz), 1.78e1.14 (146H, m, v
br), 1.05 (3H, d, J 6.9 Hz), 0.90 (3H, d, J 6.9 Hz), 0.89 (6H, t, J 6.9 Hz),
0.71e0.64 (1H, m), 0.48e0.42 (1H, m), 0.22e0.08 (3H, m); dC
(126 MHz, CDCl3): 215.4, 180.0, 72.1, 50.9, 46.3, 41.1, 38.1, 37.4, 35.5,
34.5, 33.0, 31.9, 30.1, 29.7 (v br), 29.66, 29.61, 29.52, 29.50, 29.47,
29.44, 29.37, 29.34, 27.3, 27.2, 26.1, 25.7, 23.7, 22.7,19.7,18.6,16.3,14.1,
1375, 1240, 1176, 1021 cmꢂ1
.
3.1.12. (R)-2-{(R)-1-Hydroxy-17-[(1S,2R)-2-((1S,20S,21S)-20-
hydroxy-1,21-dimethylnonatriacontyl)-cyclopropyl]-heptadecyl}-
hexacosanoic acid (23). Lithium hydroxide monohydrate (28.2 mg,
0.67 mmol) was added to a stirred solution of ester 22 (0.030 g,
0.024 mmol) in THF (3 mL), methanol (0.2 mL) and water (0.2 mL)
at room temperature. The mixture was stirred at 45 ꢁC for 18 h, then
cooled to room temperature, petrol/ethyl acetate (5:2, 10 mL)
added and the mixture was acidified to pH 1 with 5% aq HCl by
dropwise. Further petrol/ether (5:2, 20 mL) was added and
extracted. The aqueous layer was re-extracted with petrol/ether
10.5; nmax: 3348, 2919, 2850, 1697, 1471, 1376, 1185, 1023 cmꢂ1
.
3.1.15. (R)-2-((R)-1-Acetoxy-17-{(1S,2R)-2-[(1S,20S,21S)-20-(tetra-
hydro-2H-pyran-2-yl)-1,21-dimethyl-nonatriacontyl]cyclopropyl}
heptadecyl)hexacosnoic acid methyl ester (30). Pyridinium p-tolu-
ene sulfonate (0.10 g, 0.36 mmol) in dry dichloromethane (1 mL)
was added to a stirred solution of ester 22 (1.04 g, 0.720 mmol) and

G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
6293
The organic layer was separated and the aqueous layer was
re-extracted with petrol/ethyl acetate (2ꢃ50 mL). The com-
bined organic layers were washed with water, dried and
evaporated. Column chromatography on silica eluting with
petrol/ethyl acetate (20:1) to give a white semi-solid, the title
compound 31 (0.92 g, 84%) [Found (MþNa)þ: 1502.4569.
C98H194O5SiþNa requires: 1502.4593]. This showed dH
(500 MHz, CDCl3): 4.66 (1H, dt, J 6.95, 3.5 Hz), 3.95e3.89 (1H,
m), 3.84e3.81 (1H, m), 3.49e3.42 (1H, m), 2.53 (1H, ddd, J 9.15,
6.3, 3.15 Hz), 1.84e1.80 (1H, m), 1.72e1.68 (3H, m), 1.57e1.53
(18H, br m), 1.26 (138H, br s), 0.93 (9H, s), 0.90 (3H, d, J 6.6 Hz),
0.88 (3H, t, J 2.85 Hz), 0.87 (3H, t, J 2.85 Hz), 0.85 (3H, d, J
6.65 Hz), 0.68e0.63 (1H, m), 0.48e0.41 (1H, m), 0.21e0.09 (3H,
m), 0.15 (3H, s), 0.14 (3H, m); dC (126 MHz, CDCl3): 173.1, 73.7,
62.9, 62.8, 38.1, 37.4, 34.5, 32.0, 31.9, 31.4, 30.1, 29.7, 29.65, 29.6,
29.5, 29.46, 29.4, 29.36 (very broad), 27.4, 27.3, 26.1, 25.7, 22.7,
22.3, 19.7, 18.6, 17.9, 14.1, 10.5, 9.8, ꢂ4.3, ꢂ4.9; nmax/cmꢂ1: 2923,
2853, 1708, 1465, 1377, 1259, 1119, 1082, 1027, 835, 779, 728.
freshly distilled dihydro-2H-pyran (0.12 mL, 1.4 mmol) in dry
dichloromethane (5 mL) at room temperature under nitrogen. After
stirring for 1.5 h, the reaction was quenched with satd aq NaHCO3
(10 mL). The product was extracted with dichloromethane
(3ꢃ50 mL) and the combined organic layers were dried and
evaporated. Column chromatography, eluting with petrol/ethyl
acetate (10:1) with a few drops of Et3N gave the title compound as
a white semi-solid as a mixture of diastereoisomers (1.04 g, 94%)
[Found (MþNa)þ: 1444.3946. C95H184O6þNa requires: 1444.4093],
which showed dH (500 MHz, CDCl3): 5.09 (1H, ddd, J 11.05, 8.2,
4.1 Hz), 4.65 (2H, td, J 16.4, 3.45 Hz), 3.90 (1H, m), 3.68 (3H, s),
3.49e3.43 (2H, m), 2.62 (1H, ddd, J 10.7, 6.95, 4.4 Hz), 2.03 (3H, s),
1.26 (148H, v br s), 0.90 (3H, d, J 6.6 Hz), 0.89 (6H, t, J 6.95 Hz), 0.87
(6H, t, J 4.7 Hz), 0.85 (3H, d, J 6.3 Hz), 0.7e0.64 (1H, m), 0.47e0.43
(1H, m), 0.22e0.09 (3H, m); dC (126 MHz, CDCl3): 173.9, 98.5, 97.8,
81.5, 80.9, 74.1, 51.5, 49.6, 38.1, 37.4, 36.5, 35.2, 34.5, 32.5, 32.1, 31.9,
31.8, 31.5, 31.3, 31.2, 30.1, 30.0, 29.96, 29.7, 29.7, 29.7, 29.6, 28.5,
29.4, 29.35, 28.1, 27.6, 27.55, 27.5, 27.3, 26.2, 25.8, 25.7, 25.6, 25.0,
22.7, 21.0, 20.1, 19.8, 19.7, 18.6, 15.2, 14.9, 14.1, 10.5; nmax/cmꢂ1: 2918,
2850, 1744, 1476, 1372, 1236, 1165, 1132, 1077, 1023, 721.
3.1.17. (R)-2-{(R)-17-[(1S,2R)-2-((1S,21S)-1,21-Dimethyl-20-oxonon
atriacontyl)cyclopropyl]-1-(tert-butyldimethylsilanyloxy) heptadecyl}
hexacosanoic acid methyl ester (32).
3.1.16. (2R)-2-((1R)-1-(tert-Butyldimethylsilyloxy)-17-(2-((2S,21S,
22S)-22-methyl-21-(tetra-hydro-2H-pyran-2-yloxy)tetra-contan-2-
yl)cyclopropyl)heptadecyl)hexacosanoic acid (31).
(i) Pyridinium-p-toluene sulfonate (0.20 g, 0.79 mmol) was added
to a stirred solution of acid 31 (0.90 g, 0.61 mmol) in THF
(15 mL), MeOH (2 mL) and stirred at 47 ꢁC for 18 h, when TLC
showed that the reaction was almost complete. Satd aq sodium
bicarbonate (3 drops) was added and the product was extracted
with petrol/ethyl acetate (3ꢃ100 mL, 5:1). The combined or-
ganic layers were dried and evaporated. Column chromatogra-
phy eluting with petrol/ethyl acetate (10:1) gave a white semi-
solid, (R)-2-{(R)-1-(tert-butyldimethylsilanyloxy)-17-[(1S,2R)-
2-((1S,20S,21S)-20-hydroxy-1,21-dimethylnonatria-contyl)cyc-
lopropyl]heptadecyl}hexacosanoic acid (0.62 g, 73%) [Found
(MþNa)þ: 1418.4087; C93H186O4SiþNa requires: 1418.4018],
which showed dH (500 MHz, CDCl3): 3.82 (1H, ddd, 7.3, 5.1,
2.6 Hz), 3.50 (1H, dt, J 6.9, 4.8 Hz), 2.53 (1, ddd, 8.8, 6.2, 2.5 Hz),
1.73e1.68 (1H, m), 1.63e1.54 (6H, m), 1.26 (145H, v br s), 0.93
(9H, s), 0.909 (3H, d, J 6.6 Hz), 0.902 (3H, d, J 6.6 Hz), 0.87 (6H, t, J
7.6 Hz), 0.69e0.63 (1H, m), 0.48e0.42 (1H, m), 0.21e0.09 (2H,
m), 0.15 (3H, s), 0.14 (3H, s); dC (126 MHz, CDCl3): 172.3, 75.2,
73.7, 46.7, 38.2, 38.1, 37.4, 35.8, 34.5, 33.6, 31.9, 30.1, 30.0, 29.7,
29.65, 29.6, 29.54, 29.5, 29.4, 29.35, 27.4, 27.6, 26.3, 26.1, 25.7,
22.7, 19.7, 18.6, 17.9, 14.1, 13.6, 10.5, ꢂ4.2, ꢂ4.5; nmax: 3485, 2856,
(i) Lithium hydroxide monohydrate (0.46 g, 1.1 mmol) was added
to a stirred solution ester 30 (1.04 g, 0.738 mmol) inTHF (10 mL),
methanol (1 mL) and water (1.2 mL) at room temperature. The
mixture was stirred at 45 ꢁC for 18 h. It was cooled to room
temperature and a mixture of petrol/ethyl acetate (10:1, 10 mL)
was added and then it was neutralized with aq HCl (5%) to pH 7.
The mixture was extracted with petrol/ethyl acetate (5:2)
(3ꢃ25 mL). The combined organic layers were washed with
water (15 mL), dried and the solvent was evaporated. Column
chromatography eluting with petrol/ethyl acetate (5:2) gave
a semi-solid, (R)-2-{(R)-1-hydroxy-17-[(1S,2R)-2-((1S,20S,21S)-
20-(tetrahydro-2H-pyran-2-yl)-1,21-dimethylnonatriacontyl)
cyclopropyl]heptadecyl}hexacosanoic acid (1.00 g, 90%) [Found
(MþNa)þ: 1388.3735 C92H180O5þNa requires: 1388.3728],
whichshowed dH (500 MHz, CDCl3): 4.64 (1H, td, J 6.95, 3.45Hz),
3.96e3.90 (1H, m), 3.73e3.71 (1H, m), 3.50e3.43 (2H, m), 2.46
(1H, dt, J 10.1, 5.35 Hz), 1.85e1.80 (1H, m), 1.76e1.62 (3H, m),
1.53e1.51 (4H, m),1.26 (152H, v br s), 0.89 (6H, t, J 9.75 Hz), 0.85
(3H, d, J 6.95 Hz), 0.71e0.64 (1H, m), 0.48e0.42 (1H, m),
0.22e0.09 (3H, m); dC (126 MHz, CDCl3): 173.1, 98.5, 97.8, 81.5,
80.9, 74.1, 51.5, 49.6, 38.1, 37.4, 36.5, 35.2, 34.5, 32.5, 32.1, 31.9,
31.8, 31.5, 31.3, 31.2, 30.1, 30.0, 29.96, 29.72, 29.7, 29.66, 29.6,
28.5, 29.4, 29.35, 28.1, 27.6, 27.55, 27.5, 27.3, 26.2, 25.8, 25.7, 25.6,
1743, 1471, 1379, 1244, 1171, 1020 cmꢂ1
.
(ii) The above acid (0.53 g, 0.38 mmol) was dissolved in
dichloromethane (10 mL) and added in portions to a stirred
solution of PCC (24 mg, 0.11 mmol) in dichloromethane
(30 mL) at room temperature. The mixture was stirred for 2 h,
then diluted with petrol/ethyl acetate (20 mL, 10:1), filtered
over Celite and evaporated. Column chromatography eluting
with petrol/ethyl acetate (10:1) gave the title compound as
25.0, 22.7, 20.1, 19.8, 19.7, 18.6, 15.2, 14.9, 14.1, 10.5; nmax/cmꢂ1
:
3519, 2917, 2850, 1682, 1469, 1377, 1259, 1214, 1131, 1077, 1024,
868, 719.
(ii) Imidazole (0.50 g, 0.73 mmol) was added to a stirred solution
of the above acid (0.95 g, 0.73 mmol) in dry DMF (5 mL) and
dry toluene (10 mL) at room temperature followed by the
addition of tert-butyldimethylsilylchloride (1.11 g, 0.730 mmol)
and 4-dimethylaminopyridine (40 mg, 0.32 mmol). The mix-
ture was stirred at 70 ꢁC for 18 h, then the solvent was removed
under high vacuum and the residue was diluted with petrol/
ethyl acetate (1:1, 150 mL) and satd aq NaHCO3 (20 mL). The
organic layer was separated and the aqueous layer was re-
extracted with petrol/ethyl acetate (3ꢃ50 mL). The combined
organic layers were washed with water, dried and evaporated
to give a residue. This was dissolved in THF (20 mL), water
(2 mL), and methanol (1.5 mL), and potassium carbonate (0.5 g)
was added. The mixture was stirred at 45 ꢁC for 6 h, then di-
luted with petrol/ethyl acetate (10:1, 50 mL) and water (5 mL)
then acidified with potassium hydrogen sulfate to a pH 2.
a
white semi-solid, 32 (0.47 g, 88%) [Found (MþNa)þ:
1416.3886; C93H184O4SiþNa requires: 1416.3861], ½a D21
þ6.33
ꢀ
(c 0.71, CHCl3), which showed dH (500 MHz, CDCl3): 3.82 (1H,
ddd, J 7.9, 5.4, 2.6 Hz), 2.55e2.49 (1H, m), 2.41(1H, td, J 7.3,
2.2 Hz),1.55 (28H, v br s), 1.26 (123H, br s), 1.06 (3H, d, J 6.9 Hz),
0.94 (9H, s), 0.90 (3H, d, J 6.2 Hz), 0.90 (6H, t, J 7 Hz), 0.48e0.42
(1H, m), 0.21e0.16 (1H, m), 0.16 (3H, s), 0.15 (3H, s), 0.13e0.09
(1H, m); dC (126 MHz, CDCl3): 171.0, 38.9, 31.9, 29.73, 29.7,
29.66, 29.54, 29.5, 29.4, 29.36, 25.7, 22.7, 14.1, ꢂ4.9, ꢂ5.5; nmax
:
2943, 2857, 1689, 1468, 1372, 1209 cmꢂ1
.
3.1.18. (R)-2-{(R)-17-[(1S,2R)-2-((1S,21S)-1,21-Dimethyl-20-
oxononatriacontyl)-cyclopropyl]-1-hydroxyheptadecyl} hexacosanoic
acid (33). The ester 32 (0.21 g, 0.15 mmol) was stirred in dry THF

6294
G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
J 6.6 Hz), 1.47 (1H, br s) 1.47e1.20 (56H, m), 1.16e1.04 (1H, m),
0.90(3H, t, J 7 Hz) 0.88 (3H, d, J 6.6 Hz); dC (126 MHz, CDCl3): 86.2,
63.1, 57.8, 35.6, 32.8, 32.6, 32.0, 30.7, 30.2, 30.0, 29.8, 29.7, 29.6,
29.5, 29.4, 27.5, 26.3, 25.8, 22.9,14.9,14.1; nmax: 3376, 2929,1103,
(5 mL) in a dry polyethylene vial under nitrogen at room temper-
ature. Pyridine (0.1 mL) and HF$Pyridine (0.6 mL) was added and
the mixture was stirred for 17 h at 45 ꢁC, then diluted with petrol/
ethyl acetate (5:2, 10 mL) and neutralized by pouring into satd aq
NaHCO3 until no more carbon dioxide was liberated. The mixture
was extracted and the aqueous layer was re-extracted with petrol/
ethyl acetate (1:1, 2ꢃ50 mL). The combined organic layers were
washed with brine, dried and evaporated to give a residue. Column
chromatography eluting with petrol/ethyl acetate (7:3) gave the
1080 cmꢂ1
.
(ii) N-Bromosuccinimide (0.44 g, 2.46 mmol, 1.3 mol equiv) was
added in portions over 15 min to a stirred solution of the al-
cohol (1.04 g, 1.89 mmol) and triphenylphosphine (0.56 g,
2.14 mmol, 1.13 equiv) in dichloromethane (20 mL) at 0 ꢁC. The
mixture was stirred at rt for 1 h, quenched with satd aq sodium
meta-bisulfite (25 mL), then the aqueous layer was re-
extracted with dichloromethane (2ꢃ20 mL) and the com-
bined organic extracts washed with water (50 mL), dried and
evaporated. The residue was treated with petrol/ether (1:1,
50 mL), refluxed for 30 min, filtered and washed with petrol/
ether (1:1, 25 mL). The filtrate was evaporated. Column chro-
matography eluting with petrol/ether (10:1) gave a white solid,
(15S,16S)-1-bromo-15-methoxy-16-methyltetratriacontane
title compound as a white solid 33 (0.16 g, 84%), ½a D19
þ10.55 (c 0.54,
ꢀ
CHCl3), mp 67e68 ꢁC [Found (MþNa)þ: 1302.2938, C87H170O4þNa
requires: 1302.2991]. This showed dH (500 MHz, CDCl3): 3.71 (1H,
dt, J 7.9, 4.75 Hz), 2.38 (1H, m), 2.35e2.32 (1H, m), 2.29 (2H, td, J
9.45, 1.9 Hz), 1.77e1.70 (1H, m), 1.66e1.59 (2H, m), 1.56e1.46 (5H,
m),1.26 (142, br s),1.06 (2H, d, J 6.95 Hz), 0.90 (2H, d, J 6.95 Hz), 0.88
(6H, t, J 6.65 Hz), 0.69e0.64 (1H, m), 0.47e0.42 (1H, m), 0.21e0.17
(1H, m), 0.16e0.08 (2H, m); dC (126 MHz, CDCl3): 215.5, 178.5, 72.11,
50.7, 46.3, 41.2, 38.1, 37.4, 35.6, 34.5, 33.0, 31.9, 29.73, 29.7, 29.65,
29.6, 29.5, 29.47, 29.4, 29.36, 29.3, 27.32, 26.1, 23.7, 22.7, 19.7, 18.6,
(0.76 g, 83%), ½a D21
ꢀ
ꢂ7.74 (CHCl3, 1.25
m
mol) [Found (MþNa)þ:
623.4713; C36H7379BrO þ Na requires: 623.4742], which
showed dH (500 MHz, CDCl3): 3.46 (2H, t, J 6.8 Hz), 3.39 (3H, s),
3.03e2.98 (1H, m), 1.91 (2H, pent, J 6.8 Hz), 1.71e1.65 (1H, m),
1.52e1.26 (58H, m), 0.91 (3H, t, J 6.4 Hz), 0.88 (3H, d, J 6.8 Hz);
dC (126 MHz, CDCl3): 85.8, 57.9, 35.3, 34.2, 32.9, 32.6, 31.9, 30.8,
30.3, 29.9, 29.7, 29.6, 29.52, 29.48, 29.4, 28.9, 28.4, 27.7, 26.3,
16.4, 14.1, 10.5; nmax: 2922, 2853, 1716, 1685, 1470, 1037 cmꢂ1
.
3.1.19. (15S,16S)-15-Methoxy-16-methyltetratriacontyl pivalate
(35). A solution of the aldehyde 3431 (1.56 g, 3.56 mmol) and the
sulphone 8 (n¼7) (1.74 g, 4.27 mmol) in dry THF (50 mL) was stirred
under nitrogen at ꢂ10 ꢁC. Lithium bis(trimethylsilyl)amide
(5.24 mL, 5.56 mmol, 1.06 M) was added dropwise between ꢂ12
and ꢂ5 ꢁC, and the solution was stirred for 18 h. Dichloromethane
(50 mL) and satd aq ammonium chloride (50 mL) were added. The
aqueous layer was re-extracted with further dichloromethane
(2ꢃ100 mL) and the combined organic layers were dried and
evaporated. Column chromatography eluting with petrol/ether
(10:1) gave a colourless oil, (E/Z)-2,2-dimethylpropionic acid 15-
methoxy-16-methyl-tetratriacont-7-enyl ester (1.78 g, 81%). Palla-
dium on charcoal (0.2 g, 10%) was added to a stirred solution of the
above product (1.78 g, 2.87 mmol) in THF (5 mL) and IMS (40 mL).
The mixture was stirred under hydrogen at atmospheric pressure.
When no more hydrogen was absorbed, the catalyst was removed
through a pad of Celite and washed with THF (50 mL). The filtrate
was evaporated to give the title compound as a colourless oil 35
22.8, 14.9, 14.4; nmax: 2943, 2868, 1123, 743 cmꢂ1
.
(iii) The bromide (0.70 g, 1.14 mmol) in THF (3 mL) and acetone
(3 mL) was added to a stirred solution of 1-phenyl-1H-tetra-
zole-5-thiol (0.22 g, 1.26 mmol, 1.1 mol equiv) and anhydrous
potassium carbonate (0.55 g, 4.00 mmol, 3.5 mol equiv) in
acetone (15 mL) at rt. After 18 h, the solvent was evaporated
and the residue diluted with petrol/ether (1:1, 20 mL) and
water (20 mL). The aqueous layer was re-extracted with petrol/
ether (1:1, 2ꢃ10 mL). The combined organic extracts were
dried and evaporated; column chromatography eluting with
10:1 petrol/ether gave
a colourless oil, 5-((15S,16S)-15-
methoxy-16-methyltetratriacontyl-1-sulfan-yl)-1-phenyl-1H-
tetrazole (0.76 g, 93%), ½a D21
ꢀ
ꢂ6.49 (CHCl3, 1.11
mmol) [Found
(MþNa)þ: 721.5784; C43H78N4OSþNa requires: 721.5794],
which showed dH (500 MHz, CDCl3): 7.64e7.51 (5H, m), 3.39
(2H, t, J 7.3 Hz), 3.30 (3H, s), 2.99e2.94 (1H, m), 1.82 (2H, pent, J
7.4 Hz), 1.67e1.60 (1H, m), 1.49e1.20 (58H, m), 0.91 (3H, t, J
6.55 Hz), 0.87 (3H, d, J 6 Hz); dC (126 MHz, CDCl3): 154.5, 130.1,
129.8, 123.9, 85.5, 57.7, 35.3, 30.5, 30.0, 29.6, 29.5, 29.1, 28.7,
(1.57 g, 88%), ½a D22
ꢀ
ꢂ6.7 (CHCl3, 1.25
m
mol) [Found (MþNa)þ:
645.6152; C41H82O3þNa requires: 645.6161], which showed dH
(500 MHz, CDCl3): 4.04 (2H, t, J 6.6 Hz), 3.34 (3H, s), 3.02e2.96 (1H,
m), 1.66 (2H, pent, J 6.6 Hz), 1.55e1.28 (58H, m), 1.24 (9H, s),
1.14e1.03 (1H, m), 0.93 (3H, t, J 6.6 Hz), 0.90 (3H, d, J 7.0 Hz); dC
(126 MHz, CDCl3): 178.3, 85.5, 64.5, 57.7, 35.4, 32.4, 31.9, 30.9, 30.5,
29.92, 29.89, 29.7, 29.6, 29.5, 29.4, 29.3, 28.6, 27.6, 26.1, 26.0, 22.4,
26.2, 22.7, 14.9, 14.1; nmax: 2926, 2861, 1098 cmꢂ1
.
14.8, 14.1; nmax: 2935, 1749, 1134 cmꢂ1
.
(iv) m-Chloroperbenzoic acid (0.52 g, 3.04 mmol, 3.0 mol equiv) in
dichloromethane (5 mL) was added slowly to the tetrazole
(0.72 g, 1.01 mmol) and sodium hydrogen carbonate (0.38 g,
4.56 mmol, 4.5 mol equiv) in dichloromethane (5 mL) at 5 ꢁC. The
mixturewasstirredfor18hatrt,thenthesolventwasevaporated
and the residue was diluted with ethyl acetate (5 mL) and slowly
quenched withsatd aqsodiummetabisulfite (2 mL). The aqueous
layer was re-extracted with ethyl acetate (2ꢃ10 mL) and the
combined organic extracts were washed with satd aq sodium
hydrogen carbonate (10 mL) and thenwater (20 mL). The organic
extract was then dried and evaporated. Column chromatography
eluting with 1:1 petrol/ether gave the title compound as a white
3.1.20. 5-((15S,16S)-15-Methoxy-16-methyltetratriacontyl-1-
sulfonyl)-1-phenyl-1H-tetrazole (36).
(i) Lithiumaluminiumhydride(0.14g,3.79mmol)wasaddedtoTHF
(20 mL) stirred at ꢂ20 ꢁC under nitrogen. (15S,16S)-15-Methoxy-
16-methyltetratriacontyl pivalate 35 (1.57 g, 2.52 mmol) in THF
(10 mL) wasaddedslowlyand allowedtoreach RT, then heated at
reflux for 1 h. The reaction was cooled to ꢂ20 ꢁC and quenched
with satd aq sodium sulfate until a white precipitate formed. THF
(30 mL) was added and the mixture was stirred for 30 min, then
filtered through a bed of silica and the solvent evaporated. The
resulting solution was taken up in dichloromethane (50 mL),
washed with water (10 mL) then dried and the solvent evapo-
rated. Column chromatography eluting with petrol/ether (20:1,
then 1:1) gave a white solid, (15S,16S)-15-methoxy-16-methyl-
solid 36 (0.67 g, 89%), ½a D23
ꢀ
ꢂ6.28 (CHCl3, 1.02
mmol) [Found
(MþNa)þ: 753.5674; C43H78N4O3SþNa requires: 753.5692],
whichshoweddH (500MHz,CDCl3):7.71e7.70(2H, m), 7.69e7.61
(3H, m), 3.74 (2H, t, J 7.9 Hz), 3.34 (3H, s), 2.97e2.95 (1H, m),1.96
(2H, pent, J 7.9 Hz), 1.63e1.58 (1H, m), 1.50 (2H, pent, J 7.6 Hz),
1.45e1.22 (56H, m), 0.89 (3H, t, J 6.6 Hz), 0.85 (3H, d, J 6.7 Hz); dC
(126 MHz, CDCl3): 153.5,133.1,131.5,130.3,125.1, 85.5, 57.7, 56.0,
tetratriacontan-1-ol (1.04 g, 79%), ½a D20
ꢀ
ꢂ8.97 (CHCl3, 1.22
mmol)
[Found (MþNa)þ: 561.5584; C36H74O2þNa requires: 561.5586],
which showed dH (500 MHz, CDCl3): 3.70 (2H, t, J 6.6 Hz), 3.33
(3H, s), 3.01e2.96 (1H, m), 1.66e1.64 (1H, m), 1.61 (2H, pent,

G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
6295
35.3, 32.4, 31.9, 30.5, 30.0, 29.9, 29.7, 29.7, 29.62, 29.60, 29.5, 29.4,
through silica and the solvent evaporated. Column chroma-
tography eluting with petrol/ether (1:1) gave a colourless oil,
9-((1S,2R)-2-((2S,19S,20S)-19-methoxy-20-methyloctatria-
29.2, 28.9, 26.5, 22.8, 22.0,15.1,14.4; nmax: 2947, 2852,1321,1164,
1097 cmꢂ1
.
contan-2-yl)cyclopropyl)nonan-1-ol (260 mg, 72%), ½a D19
ꢂ6.11
ꢀ
(CHCl3, 1.08
m
mol) [Found (MþNa)þ: 783.7984; C52H104O2þNa
3.1.21. 9-((1S,2R)-2-((S)-4-Oxobutan-2-yl)cyclopropyl)nonyl pivalate
(37). 9-((1S,2R)-2-((S)-4-Hydroxybutan-2-yl)cyclopropyl)nonyl piv-
alate 11 (n¼8) (see Supplementary data) (0.42 g, 1.23 mmol) was
added to a stirred suspension of PCC (0.67 g, 3.09 mmol, 2.5 mol
equiv) in dichloromethane (10 mL). The mixture was stirred for 2 h at
rt, then diluted with ether (50 mL). The mixture was filtered through
a bed of silica and washed with ether (2ꢃ10 mL), and the solvent
evaporated. Column chromatography eluting with petrol/ether (5:2)
requires: 783.7934], which showed dH (500 MHz, CDCl3): 4.03
(2H, t, J 6.65 Hz), 3.69 (1H, m), 3.35 (3H, s), 1.52e1.20 (84H, br
m including br s at 1.26), 0.90e0.82 (10H, m), 0.46e0.44 (1H,
m), 0.22e0.18 (1H, m), 0.17e0.14 (1H, m), 0.13e0.09 (1H, m); dC
(126 MHz, CDCl3): 85.5, 63.1, 57.7, 38.1, 37.4, 35.4, 34.5, 32.8,
32.4, 31.9, 30.5, 30.0, 29.9, 29.7, 29.6, 29.5, 29.4, 29.3, 27.6, 27.3,
26.2, 25.8, 22.7, 19.7; nmax: 3343, 2975, 2847 cmꢂ1
.
(ii) The alcohol (0.260 g, 0.343 mmol) was added to a stirred
suspension of PCC (0.22 g, 1.03 mmol, 3 mol equiv) in
dichloromethane (10 mL). After 1 h at rt, it was diluted with
ether (10 mL). The mixture was filtered through a bed of silica
and washed with ether (2ꢃ5 mL), and the solvent evaporated.
Column chromatography eluting with 10:1 petrol/ether gave
gave the title compound as a colourless oil 37 (0.39 g, 93%), ½a D22
ꢀ
þ20.47 (CHCl3, 1.08
m
mol) [Found (MþNa)þ: 361.2719; C21H38O3þNa
requires: 361.2718], which showed dH (500 MHz, CDCl3): 9.78 (1H, s),
2.50 (1H, ddd, J 15.75, 6.3, 1.9 Hz), 2.35 (1H, ddd, J 15.75, 7.9, 2.5 Hz),
1.61 (2H, pent, J 6.6 Hz), 1.32e1.13 (26H, m), 1.00 (3H, d, J 6.65 Hz),
0.49 (1H, m), 0.34e0.21 (3H, m); dC (126 MHz, CDCl3): 202.9, 178.6,
64.4, 51.4, 38.7, 34.1, 33.9, 29.6, 29.51, 29.48, 29.2, 28.6, 27.2, 25.9,
a
colourless oil, 9-((1R,2R)-2-((2S,19S,20S)-19-methoxy-20-
methyloctatriacontan-2-yl)cyclopropyl)nonanal 39 (0.24 g,
25.6, 20.0, 18.8, 11.4; nmax: 2924, 2878, 1727 cmꢂ1
.
96%),
½
a 1D9
ꢀ
ꢂ3.45 (CHCl3, 1.25
m
mol) [Found (MþNa)þ:
781.7756; C52H102O2þNa requires: 781.7777], which showed
dH (500 MHz, CDCl3): 9.77 (1H, br t, J 1.85 Hz), 3.38 (3H, s),
2.97e2.95 (1H, m), 2.43 (2H, dt, J 1.85, 7.55 Hz), 1.99e1.97 (1H,
m), 1.65e1.61 (1H, m), 1.56 (2H, m), 1.40e1.09 (78H, br m in-
cluding br s at 1.27), 0.89 (6H, dt, J 2.85, 6.6 Hz), 0.85 (3H, d, J
6.6 Hz), 0.48e0.43 (1H, m), 0.22e0.18 (1H, m), 0.17e0.14 (1H,
m), 0.13e0.09 (1H, m); dC (126 MHz, CDCl3): 205.1, 85.5, 65.6,
57.7, 43.9, 38.1, 37.4, 35.4, 34.4, 32.8, 32.4, 31.9, 30.5, 30.0, 29.9,
29.7, 29.6, 29.5, 29.4, 29.3, 27.6, 27.3, 26.2, 25.8, 22.7, 19.7, 18.6,
3.1.22. 9-((1S,2R)-2-((2S,19S,20S)-19-Methoxy-20-methyloctatri-
acontan-2-yl)cyclopropyl)nonyl pivalate (38). Lithium hexame-
thyldisilazide (0.92 mL, 0.98 mmol, 1.06 M) was added dropwise to
a stirred solution of sulfone 36 (670 mg, 0.90 mmol) and the al-
dehyde 37 (255 mg, 0.752 mmol) in dry THF (10 mL) under nitrogen
at ꢂ20 ꢁC. The temperature rose to ꢂ10 ꢁC during the addition of
the base, and a yellow solution resulted. The mixture was allowed
to reach rt and was stirred for 1 h, then cooled to 0 ꢁC and quenched
with satd aq ammonium chloride (10 mL). The product was
extracted with petrol/ether (1:1, 3ꢃ10 mL). The combined organic
layers were washed with brine (20 mL), dried and evaporated to
give an oil, which was purified via column chromatography eluting
with petrol/ether (20:1) to give 9-((1S,2R)-2-[(E/Z)-(2S,19S,20S)-19-
methoxy-20-methyloctatriacont-4-en-2-yl]cyclopropyl)nonyl piv-
alate (410 mg, 54%). Dipotassium azodicarboxylate (2.49 g,
12.83 mmol, 30 mol equiv) was added to a stirred solution of the
above (410 mg, 0.487 mmol) in THF (20 mL) and methanol (10 mL)
at 10 ꢁC under nitrogen, giving a yellow precipitate. Glacial acetic
acid (1 mL) in THF (2 mL) was added dropwise over 48 h, after
which a white precipitate had formed. The mixture was cooled to
16.5, 14.3, 10.5; nmax: 2984, 2875, 1724 cmꢂ1
.
3.1.24. Methyl 2-((1R,2R)-1-(tert-butyldimethylsilyloxy)-19-((1S,2R)-
2-((2S,18S,19S)-18-methoxy-19-methylheptatriacontan-2-yl)cyclo-
propyl)nonadecyl)hexacosanoate (41). Lithium hexamethyldisila-
zide (0.29 mL, 0.31 mmol, 1.06 M) was added dropwise to a stirred
solution of sulfone 40 (183 mg, 0.206 mmol) (see Supplementary
data) and aldehyde 39 (172 mg, 0.227 mmol) in dry THF (10 mL)
under nitrogen at ꢂ20 ꢁC. The temperature rose to ꢂ10 ꢁC during the
addition of the base, and a yellow solution resulted. The mixture was
allowed to reach rt and was stirred for 1 h, then cooled to 0 ꢁC and
quenched with satd aq ammonium chloride (10 mL). The product
was extracted with petrol/ether (1:1, 3ꢃ10 mL). The combined or-
ganic layers were washed with brine (20 mL), dried and evaporated
to give an oil. Column chromatography eluting with 20:1 petrol/
ether gave methyl 2-((R)-(E/Z)-1-(tert-butyl-dimethylsilyloxy)-19-
((1S,2R)-2-((2S,18S,19S)-18-methoxy-19-methylheptatriacontan-2-
yl)cyclopropyl)-nonadec-10-enyl)hexacosanoate (80.6 mg, 28%).
Dipotassium azodicarboxylate (0.33 g, 1.7 mmol, 30 mol equiv) was
added to a stirred solution of the above compound (80.6 mg,
0.057 mmol) in THF (5 mL) and methanol (5 mL) at 10 ꢁC under
nitrogen, giving a yellow precipitate. Glacial acetic acid (1 mL) in THF
(2 mL) was added over 48 h, after which a white precipitate had
formed. The mixture was cooled to 0 ꢁC, poured slowly into satd aq
sodium hydrogen carbonate (5 mL), then extracted with petrol/ether
(1:1, 3ꢃ10 mL). The combined organic layers were washed with
water (10 mL), dried and evaporated to give a thick oil, which slowly
solidified. Column chromatography eluting with 10:1 petrol/ether
gave the title compound as a waxy white solid, 41 (75.7 mg, 94%),
0
ꢁC and poured slowly into satd aq sodium hydrogen carbonate
(5 mL) and then extracted with petrol/ether (1:1, 3ꢃ25 mL). The
combined organic layers were washed with water (10 mL), dried
and evaporated to give a thick oil, which slowly solidified. Column
chromatography eluting with 10:1 petrol/ether gave the title
compound as a colourless oil 38 (400 mg, 97%), ½a D21
ꢂ6.85 (CHCl3,
ꢀ
0.87
m
mol) [Found (MþNa)þ: 867.8511; C57H112O3þNa requires:
867.8509], which showed dH (500 MHz, CDCl3): 4.05 (2H, t, J
6.65 Hz), 3.70 (1H, m), 3.35 (3H, s), 1.60 (9H, s), 1.44e1.19 (84H, br m
including br s at 1.26), 0.92e0.84 (10H, m), 0.47e0.44 (1H, m),
0.22e0.18 (1H, m), 0.17e0.14 (1H, m), 0.13e0.09 (1H, m); dC
(126 MHz, CDCl3): 85.5, 65.8, 63.1, 57.7, 38.1, 35.4, 34.5, 32.8, 32.4,
31.9, 30.5, 30.1, 30.0, 29.9, 29.7, 29.6, 29.5, 29.4, 27.6, 27.3, 26.2, 26.1,
25.8, 22.7,19.7,18.6,15.3,14.9,14.1,10.5; nmax: 2918, 2857,1745 cmꢂ1
3.1.23. 9-((1R,2R)-2-((2S,19S,20S)-19-Methoxy-20-methyloctatriacontan-
2-yl)cyclopropyl)nonanal (39).
(i) Lithium aluminium hydride (36.0 mg, 0.95 mmol, 2 mol equiv)
was added to stirred THF (5 mL, HPLC grade) at ꢂ20 ꢁC under
nitrogen. A solution of pivalate 38 (400 mg, 0.474 mmol) in THF
(5 mL, HPLC grade) was added slowly and then the reaction
was allowed to reach rt, refluxed for 1 h, cooled to ꢂ20 ꢁC, then
quenched with satd aq sodium sulfate until a white precipitate
formed. The mixture was stirred for 30 min and then filtered
½
a 2D4
ꢀ
ꢂ1.45 (CHCl3, 0.86
m
mol) [Found (MþNa)þ: 1446.21;
C95H190O4SiþNa requires: 1446.43], which showed dH (500 MHz,
CDCl3): 3.92e3.90 (1H, m), 3.66 (3H, s), 3.35 (3H, s), 2.97e2.95 (1H,
m), 2.54 (1H, ddd, J 3.75, 7.25,11 Hz),1.58e1.18 (150H, br m including
br s at 1.27), 0.91e0.85 (21H, m), 0.48e0.44 (1H, m), 0.22e0.18 (1H,
m), 0.17e0.14 (1H, m), 0.13e0.09 (1H, m), 0.05 (3H, s), 0.03 (3H, s); dC

6296
G. Koza et al. / Tetrahedron 69 (2013) 6285e6296
(126 MHz, CDCl3): 175.1, 125.5, 85.5, 73.2, 65.9, 57.7, 51.6, 38.1, 37.4,
37.1, 35.8, 35.4, 34.5, 33.7, 32.8, 32.4, 31.9, 31.1, 30.5, 30.3, 30.1, 30.0,
29.9, 29.8, 29.7, 29.64, 29.60, 29.52, 29.49, 29.4, 27.8, 27.6, 27.5, 27.3,
26.2, 26.1, 25.8, 23.7, 22.7, 19.7, 18.6, 18.0, 14.9, 14.1, 10.5, ꢂ4.4, ꢂ4.9;
References and notes
1. Minnikin, D. E. In The Biology of the Mycobacteria; Standford, J., Ed.; Academic:
San Diego, CA, 1982; pp 95e184.
2. Barry, C. E.; Lee, R. E.; Mdluli, K.; Sampson, A. E.; Schoeder, B. G.; Slayden, R. A.;
Yuan, Y. Prog. Lipid Res. 1998, 37, 143e179.
nmax: 2923, 2852, 1741, 1465 cmꢂ1
.
ꢀ
ꢀ
3. Marrakchi, H.; Bardou, F.; Laneelle, M.-A.; Daffe, M. In Mycobacterial Cell En-
ꢀ
velope; Daffe, M., Reyrat, J. M., Eds.; 2008; pp 41e62.
3.1.25. (R)-2-((R)-1-Hydroxy-19-((1S,2R)-2-((2S,18S,19S)-18-
methoxy-19-methylheptatriacontan-2-yl)cyclopropyl)nonadecyl)hex-
acosanoic acid (42).
ꢀ
ꢀ
4. Asselineau, C.; Asselineau, J.; Laneelle, G.; Laneelle, M. A. Prog. Lipid Res. 2002,
41, 501e523.
5. Watanabe, M.; Aoyagi, Y.; Ridell, M.; Minnikin, D. E. Microbiology 2001, 147,
1825e1837.
(i) A dry polyethylene vial equipped with a rubber septum was
charged with ester 41 (0.070 g, 0.049 mmol) in dry THF (4 mL)
under nitrogen at 0 ꢁC. Pyridine (0.2 mL) and hydrogen fluo-
rideepyridine complex (0.20 mL, 0.14 mmol, 210 mol equiv)
were added and the mixture stirred for 32 h at 43 ꢁC, then slowly
poured into satd aq sodium hydrogen carbonate (10 mL) until no
more carbon dioxide was liberated. The product was extracted
with petrol/ether (1:1, 3ꢃ50 mL), dried and evaporated to give
a solid. Column chromatography eluting with 4:1 petrol/ether
gave a white solid, methyl 2-((R)-1-hydroxy-19-((1S,2R)-2-
6. Watanabe, M.; Aoyagi, Y.; Mitome, H.; Fujita, T.; Naoki, H.; Ridell, M.; Minnikin,
D. E. Microbiology 2002, 148, 1881e1902.
7. Heath, R. J.; White, S. W.; Rock, C. O. Appl. Microbiol. Biotechnol. 2002, 58,
695e703.
8. (a) Minnikin, D. E.; Polgar, N. J. Chem. Soc., Chem. Commun. 1966, 648e649; (b)
Minnikin, D. E.; Polgar, N. Tetrahedron Lett. 1966, 2643e2647.
9. (a) Asselineau, C.; Tocanne, G.; Tocanne, J. F. Bull. Soc. Chim. Fr. 1970, 4,
1455e1459; (b) Asselineau, C.; Asselineau, J. Bull. Soc. Chim. Fr. 1966,
1992e1999; (c) Tocanne, J. F.; Asselineau, C. Bull. Soc. Chim. Fr. 1968, 4519e4525.
ꢀ
10. Lacave, C.; Laneelle, M.-A.; Montrozier, H.; Rols, M.-P.; Asselineau, C. Eur. J. Bi-
ochem. 1987, 163, 369e378.
ꢀ
ꢀ
ꢀ
ꢀ
11. Daffe, M.; Laneelle, M. A.; Guillen, L. V. Eur. J. Biochem. 1988, 177, 339e340.
12. Daffe, M.; Laneelle, M. A.; Lacave, C. Res. Microbiol. 1991, 142, 397e403.
((2S,18S,
19S)-18-methoxy-19-methylheptatriacontan-2-yl)
ꢀ
13. Durand, H.; Welby, M.; Laneelle, G.; Tocanne, J.-F. Eur. J. Biochem.1979, 93,103e112.
14. Durand, H.; Gillois, M.; Tocanne, J.-F.; Laneelle, G. Eur. J. Biochem. 1979, 94,
a 2D3
ꢀ
ꢀ
cyclopropyl)-nonadecyl)-hexacosanoate (35 mg, 54%),
ꢂ1.12 (CHCl3, 0.99
½
mol), mp 63e65 ꢁC [Found (MþNa)þ:
109e118.
m
15. Moody, D. B.; Guy, M. R.; Grant, E.; Cheng, T.-Y.; Brenner, M. B.; Besra, G. S.;
Porcelli, S. A. J. Exp. Med. 2000, 192, 965e976.
16. Watanabe, R.; Yoo, Y. C.; Hata, K.; Mitobe, M.; Koike, Y.; Nishizawa, M.; Garcia,
D. M.; Nobuchi, Y.; Hiroshi, I.; Yamada, H.; Azuma, I. Vaccine 1999, 17,
1484e1492.
1332.19; C89H176O4þNa requires: 1332.35], which showed dH
(500 MHz, CDCl3): 3.72 (3H, s), 3.69e3.64 (1H, m), 3.35 (3H, s),
2.97e2.95 (1H, m), 2.44 (1H, dt, J 5.35, 9.15 Hz), 1.63e1.13 (150H,
br m including br s at 1.26), 0.91e0.85 (12H, m), 0.47e0.43 (1H,
m), 0.22e0.18 (1H, m), 0.17e0.14 (1H, m), 0.13e0.09 (1H, m); dC
(126MHz, CDCl3): 176.2, 85.5, 72.3, 57.7, 51.5, 50.9, 38.1, 37.4, 35.7,
35.3, 32.4, 31.9, 31.6, 30.5, 30.3, 30.1, 29.9, 29.7, 29.64, 29.62,
29.60, 29.58, 29.53, 29.49, 29.42, 29.38, 27.6, 27.4, 27.3, 26.2, 26.1,
25.7, 22.7, 19.7, 18.6, 15.3, 14.9, 14.1, 10.5; nmax: 3509, 2916, 2848,
17. Riley, L. W. J. Clin. Invest. 2006, 116, 1475e1478.
18. Yuan, Y.; Zhi, Y. Q.; Crane, D. D.; Barry, C. E. Mol. Microbiol. 1998, 29, 1449e1458.
ꢀ
19. Dubnau, E.; Chan, J.; Raynaud, C.; Mohan, V. P.; Laneelle, M. A.; Yu, K. M.;
ꢀ
Quemard, A.; Smith, I.; Daffe, M. Mol. Microbiol. 2000, 36, 630e637.
20. Behr, M. A.; Schroeder, B. G.; Brinkman, J. N.; Slayden, R. A.; Barry, C. E. J.
Bacteriol. 2000, 182, 3394e3399.
ꢀ
ꢀ
21. Dubnau, E.; Marrakchi, H.; Smith, I.; Daffe, M.; Quemard, A. Mol. Microbiol. 1998,
29, 1526e1528.
2360, 2341, 1727, 1714, 1468 cmꢂ1
.
22. Belley, A.; Alexander, D.; Di Pietrantonio, T.; Girard, M.; Jones, J.; Schurr, E.; Liu,
J.; Sherman, D. R.; Behr, M. A. Infect. Immun. 2004, 72, 2803e2809.
23. Barkan, D.; Hedhli, D.; Yan, H.-G.; Huygen, K.; Glickman, M. S. Infect. Immun.
2012, 80, 1958e1968.
(ii) Lithium hydroxide monohydrate (20 mg, 0.84 mmol,
30 mol equiv) was added to a stirred solution of the ester
(35 mg, 0.027 mmol) in THF (2.5 mL), methanol (0.3 mL) and
water (0.3 mL) at rt. The mixture was stirred at 43 ꢁC for 18 h,
then cooled to rt and acidified with hydrochloric acid (5%,
1 mL) and the aqueous layer extracted with warm petrol/ether
(1:1, 3ꢃ10 mL). The combined organic extracts were dried and
evaporated. Column chromatography eluting with 5:1 petrol/
ethyl acetate gave the title compound as a waxy white solid, 42
24. Barkan, D.; Liu, Z.; Sacchettini, J. ,C.; Glickman, M. S. Chem. Biol. 2009, 16,
499e509.
25. Rao, V.; Fujiwara, N.; Porcelli, S. A.; Glickman, M. S. J. Exp. Med. 2005, 201, 535e543.
26. Rao, V.; Gao, F.; Chen, B.; Jacobs, W. R.; Glickman, M. S. J. Clin. Invest. 2006, 116,
1660e1666.
27. Glickman, M. S.; Cahill, S. M.; Jacobs, W. R. J. Biol. Chem. 2001, 276, 2228e2233.
28. Yuan, Y.; Crane, D. C.; Musser, J. M.; Sreevatsan, S.; Barry, C. E. J. Biol. Chem. 1997,
272, 10041e10049.
29. Liao, R.-Z.; Georgieva, P.; Yu, J.-G.; Himo, F. Biochemistry 2011, 50, 1505e1513.
30. Al Dulayymi, J. R.; Baird, M. S.; Roberts, E. Chem. Commun. 2003, 228e229
Tetrahedron, 2005, 61, 11939e11951.
31. Al Dulayymi, J. R.; Baird, M. S.; Roberts, E.; Deysel, M.; Verschoor. Tetrahedron
2007, 63, 2571e2592.
(24.0 mg, 69%), ½a D22
ꢀ
ꢂ0.97 (CHCl3, 0.47
m
mol) [Found MþNaþ:
1318.24; C88H174O4þNa requires: 1318.33], which showed dH
(500 MHz, CDCl3): 3.74e3.70 (1H, m), 3.36 (3H, s), 2.99e2.96
(1H, m), 2.49e2.45 (1H, m), 1.79e1.72 (1H, m), 1.69e1.61 (2H,
br m), 1.55e1.10 (149H, br m including br s at 1.27), 0.91e0.85
(12H, br m including t, J 6.95 Hz), 0.48e0.43 (1H, m), 0.22e0.18
(1H, m), 0.17e0.14 (1H, m), 0.13e0.09 (1H, m); dC (126 MHz,
CDCl3): 178.7, 85.6, 72.1, 57.7, 50.6, 38.1, 37.4, 35.6, 35.3, 34.5,
32.3, 31.9, 30.5, 30.1, 30.0, 29.9, 29.73, 29.7, 29.6, 29.5, 29.4,
29.36, 27.6, 27.3, 27.25, 26.2, 26.14, 25.7, 22.69, 19.7, 18.6, 14.9,
32. Al Dulayymi, J. R.; Baird, M. S.; Roberts, E.; Minnikin, D. E. Tetrahedron 2006, 62,
11867e11880.
33. Al-Dulayymi, J. R.; Baird, M. S.; Mohammed, H.; Roberts, E.; Clegg, W. Tetra-
hedron 2006, 62, 4851e4862.
ꢀ
ꢀ
ꢀ
ꢀ
34. Quemard, A.; Laneelle, M. A.; Marrakchi, H.; Prome, D.; Daffe, M. Eur. J. Biochem.
1997, 250, 758e763.
ꢀ
ꢀ
ꢀ
ꢀ
35. Dubnau, E.; Laneelle, M. A.; Soares, S.; Benichou, A.; Vaz, T.; Prome, D.; Prome,
ꢀ
ꢀ
J.-C.; Daffe, M.; Quemard, A. Mol. Microbiol. 1997, 23, 313e322.
36. Koza, G.; Baird, M. S. Tetrahedron Lett. 2007, 48, 2165e2169.
37. Koza, G.; Theunissen, C.; Al Dulayymi, J. R.; Baird, M. S. Tetrahedron 2009, 65,
10214e10229.
14.1, 10.5; nmax: 3520, 2924, 2853, 1735, 1465 cmꢂ1
.
38. The cyclopropane region of the HNMR spectra of all the trans-cyclopropanes
reported in this work matches exactly that of a wax ester mycolic acid isolated
from M. avium (Baird, M.S.; Jones, A.; Minnikin, D.E., unpublished results).
39. Minnikin, D. E.; Lee, O. Y.-C.; Pitts, M.; Baird, M. S.; Besra, G. S. J. Archaeol. Sci.
2010, 37, 2407e2412.
Acknowledgements
R.R.R. wishes to thank the EPSRC, G.K. the Government of Tur-
key, and M.M. the Government of Iraq for the award of PhD stu-
dentships. Thanks are due to Mr. B. Grail, School of Biological
Sciences, Bangor for running MALDI mass spectra.
ꢀ
ꢀ
ꢀ
40. Laval, F.; Laneelle, M. A.; Deon, C.; Monsarrat, B.; Daffe, M. Anal. Chem. 2001, 73,
4537e4544.
41. Beukes, M.; Lemmer, Y.; Deysel, M.; Al Dulayymi, J. R.; Baird, M. S.; Koza, G.;
Iglesias, M. M.; Rowles, R. R.; Theunissen, C.; Grooten, J.; Toschi, G.; Roberts, V.
V.; Pilcher, L.; Van Wyngaardt, S.; Mathebula, N.; Balogun, M.; Stoltz, A. C.;
Verschoor, J. A. Chem. Phys. Lipids 2011, 164, 175.
42. Vander Beken, S.; Al Dulayymi, J. R.; Naessens, T.; Koza, G.; Maza-Iglesias, M.;
Powles, R. R.; Theunissen, C.; De Medts, J.; Lanckacker, E.; Baird, M. S.; Grooten,
J. Eur. J. Immunol. 2011, 41, 450e460.
43. Verschoor, J. A.; Baird, M. S.; Grooten, J. Prog. Lipid Res. 2012, 51, 325e339.
44. Baird, M.S.; Al-Dulayymi, J.R.; Theunissen, C.; Koza, G.; Vander Beken, S.;
Grooten, J.A.M.; Compounds for Use in Therapy, EP2278995 A2.
Supplementary data
Proton and carbon NMR spectra and additional experimental
detail are provided. Supplementary data related to this article can
be found at http://dx.doi.org/10.1016/j.tet.2013.04.134.