Novel, potent THC/anandamide (hybrid) analogs

Article abstract of DOI:10.1016/j.bmc.2007.08.039

The structure-activity relationship (SAR) of the end pentyl chain in anandamide (AEA) has been established to be very similar to that of Δ⁹-tetrahydrocannabinol (Δ⁹-THC). In order to broaden our understanding of the structural similarities between AEA and THC, hybrid structures 1-3 were designed. In these hybrids the aromatic ring of THC-DMH was linked to the AEA moiety through an ether linkage with the oxygen of the phenol of THC. Hybrid 1 (O-2220) was found to have very high binding affinity to CB1 receptors (K_i = 8.5 nM), and it is interesting to note that the orientation of the side chain with respect to the oxygen in the phenol is the same as in THCs. To further explore the SAR in this series the terminal carbon of the side chain was modified by adding different substituents. Several such analogs were synthesized and tested for their CB1 and CB2 binding affinities and in vivo activity (tetrad tests). The details of the synthesis and the biological activity of these compounds are described.

Full text of DOI:10.1016/j.bmc.2007.08.039

Available online at www.sciencedirect.com
Bioorganic & Medicinal Chemistry 15 (2007) 7850–7864
Novel, potent THC/anandamide (hybrid) analogs
Caryl Bourne,a Sucharita Roy,a Jenny L. Wiley,b Billy R. Martin,b
Brian F. Thomas,c Anu Mahadevana,* and Raj K. Razdana
aOrganix, Inc., Woburn, MA 01801, USA
bDepartment of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
cResearch Triangle Institute, Research Triangle Park, NC 27709, USA
Received 2 November 2006; revised 8 August 2007; accepted 22 August 2007
Available online 25 August 2007
Abstract—The structure–activity relationship (SAR) of the end pentyl chain in anandamide (AEA) has been established to be very
similar to that of D9-tetrahydrocannabinol (D9-THC). In order to broaden our understanding of the structural similarities between
AEA and THC, hybrid structures 1–3 were designed. In these hybrids the aromatic ring of THC–DMH was linked to the AEA
moiety through an ether linkage with the oxygen of the phenol of THC. Hybrid 1 (O-2220) was found to have very high binding
affinity to CB1 receptors (Ki = 8.5 nM), and it is interesting to note that the orientation of the side chain with respect to the oxygen
in the phenol is the same as in THCs. To further explore the SAR in this series the terminal carbon of the side chain was modified by
adding different substituents. Several such analogs were synthesized and tested for their CB1 and CB2 binding affinities and in vivo
activity (tetrad tests). The details of the synthesis and the biological activity of these compounds are described.
ꢀ 2007 Elsevier Ltd. All rights reserved.
1. Introduction
to CB1 receptors and very weakly to CB2 receptors. The
pharmacological activities of D9-tetrahydrocannabinol
(D9-THC) and the endogenous ligand AEA have some
key differences.12–15 For example, the onset of action
of AEA is much faster and the duration of action is
much shorter when compared with D9-THC. This is
due to the enzymatic hydrolysis of the amide bond in
AEA and the enzyme involved in the metabolic degrada-
tion of AEA, ‘fatty acid amide hydrolase’ (FAAH).
During the last few decades there has been a surge of
interest in cannabinoid pharmacology1–5 driven by the
identification of G-protein coupled cannabinoid recep-
tors.6,7 The CB1 receptor is located both inside and out-
side the CNS, and the CB2 receptor is located mainly in
the periphery. The first potent CB1 receptor antagonist
SR141716A8 was reported by Sanofi, and they also
reported the CB2 selective receptor antagonist
SR144528.9 Anandamide (AEA) was identified as the
endogenous ligand for the CB1 receptor and another
key endogenous ligand which has been identified is
2-arachidonyl-glycerol (2-Ara-Gl), which activates both
CB1 and CB2 receptors. Both AEA and 2-Ara-Gl are
present together with a family of related fatty acid glyc-
erol esters and the potency of 2-Ara-Gl was found to be
improved in the presence of the related 2-acyl-glycerols.
This effect has been termed the ‘entourage effect’ which
probably represents a pathway for regulation of endog-
enous cannabinoid activity.10 Mechoulam’s group iso-
lated another endogenous ligand ‘noladin ether’ (2-
arachidonylglyceryl ether) from porcine brain.11 It binds
In order to improve the metabolic stability of AEA, sev-
eral analogs have been synthesized which have greater
binding affinities than AEA. Makriyannis and cowork-
ers incorporated a methyl in the amide head group
which dramatically improved the metabolic stability of
AEA,16–18 while our group improved the metabolic sta-
bility by introduction of substituents on the carbon in
the 2-position of the arachidonic acid part of AEA.19–21
Our ongoing program on the SAR of classical THC’s
has revealed that the alkyl side chain has a vital effect
on pharmacological activity.22–25 It has been well estab-
lished by several groups, including ours, that the SAR of
the end pentyl chain in anandamide (AEA) is often sim-
ilar to that of the THC side chain. Branching of the side
chain in THC’s results in a dramatic increase in potency
and efficacy, whereas this modification in the AEA series
has produced only a moderate increase in potency.26,27
Keywords: Cannabinoids; Endocannabinoids; Hybrids; SAR.
*
Corresponding author. Tel.: +1 781 932 4142; fax: +1 781 933
6695; e-mail: mahadevan@organixinc.com
0968-0896/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2007.08.039

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
7851
It is also well known that AEA activates CB1 receptors
and also acts as an agonist at vanilloid VR1 receptors,
whereas D9-THC activates both CB1 and CB2 receptors
and acts as a partial agonist. Keeping these differences in
mind we designed and synthesized hybrids of THC/AEA
which we expect will provide ligands with novel pharma-
cological properties and will further our understanding
of the role of the endocannabinoid system. We had pre-
viously incorporated the DMH (dimethylheptyl) side
chain of THC into the AEA template, and to extend this
approach we designed hybrid structures that incorpo-
rated the aromatic ring of THC–DMH and used the
oxygen of the phenol/pyran ring of THC to include a
part of the AEA moiety as an ether linkage. We de-
signed and developed novel THC/AEA hybrid ligands
(1–8) (Fig. 1) that incorporate conformational restraint
in the AEA part, and the synthesis and SAR results
are described in this paper.
methyl ester 13.29,30 Partial reduction of the diyne over
‘nickel boride’ catalyst provided the diene 14.31 Depro-
tection of the silyl ether, followed by treatment of the
alcohol 15 with MsCl, Et3N gave the desired mesylate
16 in 26% overall yield. 3-(2-Methyloctan-2-yl)phenol
25 which is required for the synthesis of hybrid 1 was
synthesized starting from 3-methoxy benzoic acid
(Scheme 2). The acid was converted into its correspond-
ing Weinreb amide 19 which on treatment with hexyl
magnesium bromide afforded the ketone 21.32 Introduc-
tion of the dimethyl group was accomplished by treat-
ment of ketone 21 with TiCl4, Me2Zn to give 23,
which on demethylation with BBr3 gave the phenol
derivative 25. A similar sequence was used for the syn-
thesis of the 4-(2-methyloctan-2-yl)phenol 26 starting
from 4-methoxybenzoic acid 18. Condensation of the
mesylate 16 with the phenols 25 and 26 in the presence
of potassium hydroxide gave the desired ester precursors
27 and 28 for the target compounds 1 and 2, respec-
tively. Hydrolysis of the ester hybrid 27 with lithium
hydroxide provided the acid which was then converted
to the corresponding acid chloride by treatment with
oxalyl chloride and coupled with (R)-2-aminopropanol
to give the target compound 1 in 89%. The synthesis
of target 2 was accomplished using ester precursor 28
and following the same strategy as in the synthesis of hy-
brid 1. For the synthesis of hybrid target 3 (Scheme 3),
the alcohol 15 was converted to the iodide 32 using tri-
phenylphosphine and iodine. The iodide 32 was con-
verted into the corresponding phosphonium iodide 33
by refluxing with triphenylposphine. Treatment of the
phosphonium iodide 33 with NaHMDS converted it
into the ylide which was then reacted with the aldehyde
31 in a Wittig reaction to afford the desired hybrid ester
34. The ester 34 was treated with (R)-2-aminopropanol
in the presence of a catalytic amount of sodium cyanide
to provide the target compound 3. The synthesis of
2. Chemistry
Our general synthetic strategy is based on the introduc-
tion of the AEA moiety in the targets by coupling of
appropriately substituted phenols with the key interme-
diate 11-methanesulfonyloxy-undeca-5,8-dienoic methyl
ester 16 (Scheme 1).
11-Methanesulfonyloxy-undeca-5,8-dienoic methyl ester
16 has been efficiently synthesized in our labs starting
from homopropargyl alcohol 9, which was converted
into its silyl ether 10 by treatment with t-BDPSiCl, imid-
azole. Treatment of 10 with formaldehyde in the pres-
ence of CuCl as catalyst gave the alcohol 11.28
Bromination gave the propargyl bromide 12, which
was then coupled with methyl hex-5-ynoate in the pres-
ence of CuI as catalyst to provide the diynoic acid
OH
O
O
O
NH
OH
OH
N
H
N
H
O
O
1 (O-2220)
2 (O-2294)
3 (O-2243)
O
OH
O
OH
N
H
N
H
O
O
R
4 (O-2760) R = OH
5 (O-2874) R = Br
6 (O-2781) R = N3
7 (O-2852) R = CN
8 (O-2655)
Figure 1. THC/anandamide hybrid ligands.

7852
C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
OtBDPS
OH
OtBDPS
b
a
HO
9
10
11
c
COOMe
OtBDPS
COOMe
OtBDPS
OtBDPS
e
d
Br
14
13
12
f
COOMe
COOMe
OMs
g
OH
16
15
Scheme 1. Synthesis of the key intermediate 16. Reagents and conditions: (a) t-BDPSiCl, imidazole, DMF, 81%; (b) 37% aq HCHO, CuCl, CaCO3,
H2O, reflux, 79%; (c) CBr4, Oct3P, ether, 86%; (d) methyl hex-5-ynoate, CuI, NaI, K2CO3, DMF, 70%; (e) Ni(OAc)2, NaBH4, H2, ethylenediamine,
EtOH, 81%; (f) TBAF, AcOH, THF, 91%; (g) MsCl, Et3N, CH2Cl2, 91%.
MeO
MeO
MeO
MeO
c
a,b
d
OMe
N
COOH
O
O
17 = 3-OMe
18 = 4-OMe
19 = 3-OMe
20 = 4-OMe
21 = 3-OMe
22 = 4-OMe
23 = 3-OMe
24 = 4-OMe
e
O
HO
OH
COOMe
N
H
g,h
f
O
O
1 (O-2220)
2 (O-2294)
27 = 3-OCH2
28 = 4-OCH2
25 = 3-OH
26 = 4-OH
Scheme 2. Synthesis of hybrids 1 and 2. Reagents and conditions: (a) COCl2, DMF, CH2Cl2, 0 ꢁC; (b) CH3ONHCH3ÆHCl, Et3N, CH
(c) CH3(CH2)5MgBr, THF, reflux; (d) TiCl4, (CH3)2Zn, CH2Cl2, À78 to 0 ꢁC; (e) BBr3, CH2Cl2, 0 ꢁC to rt; (f) 25 or 26, KOH, DMF, 50 ꢁC, À50%;
(g) LiOH, MeOH, 50 ꢁC, 100%; (h) oxalylchloride, DMF, benzene, (R)-2-aminopropanol, 64, 89%.
targets 4–7 was accomplished via the same strategy used
in the synthesis of hybrid 1. The appropriate phenol 39
(Scheme 4) for the synthesis of targets 4–7 was synthe-
sized starting from the commercially available 3-meth-
oxybenzonitrile. Treatment of 3-methoxy benzonitrile
with (4-phenoxybutyl) magnesium bromide gave the de-
sired ketone 35. Introduction of the dimethyl group was
accomplished by treatment of ketone 35 with TiCl4,
Me2Zn to give 36, which on demethylation with BBr3
gave the phenol 37. The bromide derivative 37 was
converted to the alcohol derivative 38 using HMPA,
H2O which was then selectively protected with tert-
butyldimethylsilyl chloride to give the desired phenol
39 in 14% overall yield.33
The phenol 39 on coupling with the mesylate 16 afforded
the ester 40 (Scheme 5). Deprotection of the silyl pro-
tecting group in 40 followed by treatment of the alcohol
41 with MsCl, Et3N provided the mesylate, which on
further treatment with NaN3 furnished compound 42.

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
7853
O
O
COOH
a, b, c
e, f
d
29
30
31
COOMe
COOMe
COOMe
g
h
OH
I
PPh3I
15
32
33
i
OH
O
O
OMe
NH
j
3 (O-2243)
34
Scheme 3. Synthesis of hybrid 3. Reagents and conditions: (a) COCl2, DMF, CH2Cl2, 0 ꢁC; (b) CH3ONHCH3ÆHCI, Et3N, CH2Cl2, rt; (c)
CH3(CH2)5MgBr, THF, reflux, 55%, 3 steps; (d) TiCl4, (CH3)2Zn, CH2Cl2, À78 to 0 ꢁC, 90%; (e) NBS, AIBN, CCI4, reflux, 85%; (f) (Bu4N)2Cr2O7,
CHCI3, reflux, 87%; (g) Ph3P, Imidazole, I2, CH3CN–Et2O, 0 ꢁC, 90%; (h) Ph3P, CH3CN, reflux, 90%; (i) NHDMS, THF, HMPA, À78 ꢁC, 31,
À78 ꢁC to rt, 50%; (j) (R)-2-Amino propanol, NaCNÆMeOH, sealed tube, 100%.
OMe
OMe
OMe
a
b
OPh
OPh
CN
O
35
36
c
OH
OH
OH
e
d
OtBDMS
OH
Br
39
38
37
Scheme 4. Synthesis of phenolic intermediate 39. Reagents and conditions: (a) Br(CH2)4OPh, Mg, THF, 64%; (b) TiCl4, (CH3)2Zn, CH2Cl2, À78 to
À10 ꢁC, 60%; (c) BBr3, CH2Cl2, 0 ꢁC to rt, 93%; (d) HMPA/H2O (8:2), 100 ꢁC, 70%; (e) t-BDMSCl, imidazole, DMF, 55%.
Bromo compound 43 was synthesized by bromination of
41 with CBr4, Oct3P. Treatment of the bromide 43 with
NaCN gave the hybrid ester 44. Target compound 4 was
synthesized by treatment of 40 with (R)-2-aminopropa-
nol in the presence of catalytic amount of NaCN fol-
lowed by deprotection of the silyl protecting group
with TBAF. The ester hybrids 43 and 44 were hydro-
lyzed to the corresponding acids and coupled with (R)-
2-aminopropanol under the mixed anhydride condition
using ClCOOEt to give the target compounds 5 and 7,
respectively. Hydrolysis of the ester hybrid 42 to the cor-
responding acid and coupling with (R)-2-aminopropa-
nol under the acid chloride condition using oxalyl
chloride afforded the target compound 6. The synthesis
of target compound 8 (Scheme 6) involved using syn-
thon 45 which has been previously synthesized and
reported by us.29 Coupling of phenol 25 (Scheme 2) with
the mesylate of alcohol 45 gave the desired ester 46
(Scheme 6). The ester hybrid 46 was hydrolyzed to the
corresponding acid 47 and coupled with (R)-2-amino-
propanol under the mixed anhydride condition using
ClCOOEt to provide the target compound 8.
In summary we have developed a facile and convergent
route for the synthesis of the hybrid analogs via the key
intermediate 16.
3. Results and discussion
The hybrid 1 (O-2220) (Table 1) was found to have good
binding affinity to CB1 receptors (Ki = 8.5 nM). Com-
parison of the results obtained with the hybrids revealed
that the orientation of the side chain in hybrid 1 was
important, and it is interesting to note that in 1 the ori-
entation of the side chain to the phenolic oxygen is the

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C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
O
OH
COOMe
C
N
H
COOMe
OMs
a
c, b
O
O
R
OH
16
40 R = OTBDMS
4 (O-2760)
b
41 R = OH
e, f
d
COOMe
COOMe
COOMe
g
O
O
O
N3
Br
CN
42
43
44
h, j
h, j
h, i
O
O
O
OH
OH
OH
C
N
C
N
H
C
N
H
H
O
O
O
N3
Br
CN
6 (O-2781)
5 (O-2874)
7 (O-2852)
Scheme 5. Synthesis of side chain modified hybrids. Reagents and conditions: (a) 39, KOH, DMF, 50 ꢁC, 62%; (b) TBAF, AcOH; (c) (R)-2-amino
propanol, NaCN, MeOH, sealed tube, 64%; (d) CBr4, Oct3P, ether, 88%; (e) MsCl, Et3N, CH2Cl2; (f) NaN3, DMF, (g) NaCN, DMSO, 65%;
(h) LiOH, MeOH; (i) (COCl)2, DMF, CH2Cl2, 0 ꢁC, (R)-2-mino propanol; (j) ClCOOEt, Et3N, CH3CN, 0 ꢁC, (R)-2-amino propanol.
O
O
OMe
a, b
OMe
O
OH
45
46
c
O
O
OH
OH
N
H
d
O
O
8 (O-2655)
47
Scheme 6. Synthesis of hybrid analog 8. Reagents and conditions: (a) MsCl, Et3N, CH2Cl2, 73%; (b) 25, KOH, DMF, 50 ꢁC, 53%; (c) LiOH, MeOH,
50 ꢁC, 60%; (d) ClCOOEt, Et3N, CH2Cl2, 0 ꢁC, (R)-2-aminopropanol, 75%.
same as in THC. When the orientation was changed to
the C4-position as in 2 (O-2294) (CB1 Ki = 195 39),
the binding affinity decreased 23-fold and activity in
the tetrad tests was absent. The synthesis of the hybrid
with an ether linkage at the C-2 position was attempted.
However, our initial attempts were not successful due to
the steric hinderance of the adjacent dimethylheptyl
group. Hence, the hybrid 3 (O-2243) was synthesized
in which we have a double bond in place of the ether lin-
ker. Hybrid 3 (O-2243) (CB1 Ki = 86 8.7) shows mod-
erate binding affinity for CB1 receptors and moderate
potency in two of the tetrad tests. In order to observe
the effect of the change in length of the unsaturated
backbone, we synthesized
8
(O-2655) (CB1
Ki = 131 14 nM). The introduction of the extra double
bond was, however, found to be detrimental to the CB1
receptor binding affinity and in vivo activity.
To further explore the SAR of compound 1, several ana-
logs were synthesized (Fig. 1) with varying functional
groups at the terminal end of the chain (Table 1). The
SAR points out that the presence of a hydroxyl group
on the terminal carbon of the chain (O-2760) decreased
binding affinity to the CB1 receptors but slightly in-
creased selectivity to CB2 receptors. In the tetrad tests,
the potency in depressing spontaneous activity and

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
Table 1. Receptor affinity and pharmacological potency of the hybrid analogs
7855
Compound
CB1 (Ki)
89 1035
44 1234
0.77 0.1135
8.55 1.83
CB2 (Ki)
371 10235
44 1734
SA (ED50
)
TF (ED50
)
RT (ED50
)
RI (ED50)
AEA
51.515
2.935
0.2735
17.815
4.835
0.1435
76.315
4.535
0.1535
55.015
4.835
0.1735
D8-THC
D8-THC–DMH
O-2220
O-2294
O-2243
O-2760
O-2781
O-2874
O-2852
O-2655
ND
21.48 0.40
78.22 9.26
257.33 3.49
10.90 0.94
7.46 0.71
2.52 0.35
3.13 0.44
189 23.39
3.73 (2.63–5.30)
44.9% at 30
8.45 (6.26–11.41)
30.7% at 30
50% at 30
7.80 (4.46–13.62)
À0.5 ꢁC at 30
À0.87 ꢁC at 30
2.8 (1.7–4.6)
ꢀ2.1
9.66 (7.78–11.98)
13.4% at 30
194.85 38.8
86.33 8.74
78.97 8.34
8.87 2.44
25.7 (17.3–38.1)
1.1 (0.54–2.1)
0.7 (0.5–1.0)
27.7 (18.9–40.4)
0.7 (0.52–0.91)
1.4 (1.1–1.7)
0.6 (0.43–0.86)
0.8 (0.61–0.97)
0.2 (0.16–0.35)
0.04 (0.02–0.07)
61% at 30
2.74 0.63
5.51 0.50
131.33 13.54
0.2 (0.14–0.33)
0.04 (0.02–0.07)
55% at 30
ꢀ1.95
0.3 (0.25–0.39)
0.04 (0.02–0.07)
22% at 30
ꢀ0.66
À0.9 at 30
Binding affinity results are presented as Ki (nM); mice were injected iv with each analog and tested for suppression of spontaneous activity (SA),
production of antinociception in the tail-flick procedure (TF), change in rectal temperature (RT) and production of ring immobility (RI). For
compounds that produced dose-dependent effects, the results are presented as ED50s (lmol/kg). Approximate ED50s (indicated by ꢀ) are given when
the highest dose tested produced half of the theoretical maximum response (e.g., temperature drop of À3 ꢁC). When dose-dependence was not
obtained and the maximum effect did not approach the theoretical maximum for the test, magnitude of maximal effect was indicated along with the
dose (mg/kg) at which it occurred (e.g., À0.9 at 30 indicates À0.9 ꢁC drop in body temperature at 30 mg/kg). Doses higher than 30 mg/kg were not
tested. Superscript numbers in table indicate reference numbers for previously reported data.
rectal temperature was increased 3-fold whereas the po-
tency in producing analgesia (TF) and relative immobil-
ity (RI) was increased 14-fold. The azido substituent
(O-2781) on the other hand has no effect on the binding
affinity but showed increased potency in the tetrad tests.
However, the bromo (O-2874) and the cyano (O-2852)
substituents produced an increase both in the binding
affinity and potency. The latter results are consistent
with our previous work that showed increases in affinity
and potency through bromo and cyano substitutions to
the terminal end of the side chain of D8-THC.34,35
O-2220, the side chains of O-2294 and O-2243 do not
align as well as O-2220 to the side chain orientation of
D9-THC (Fig. 3). The conformations obtained for O-
2220 were similar to those determined by Barnett-Norris
et al.37 using the method of conformational memories
(CM) to study the conformations available to a series
of ethanolamide fatty acid acyl chain congeners. These
studies also suggested that anandamide and its congen-
ers adopt tightly curved U/J-shaped conformations to
interact with the TMH 2-3-7 region of CB1. We plan
to develop a pharmacophore for our hybrid AEA ana-
logs and subsequently we will use the model’s predictive
ability to design more compounds.
Our group has previously reported good AEA and D9-
THC overlays (Thomas’s model), which could predict
by QSAR the potencies of various AEA analogs with
a reasonable degree of accuracy.36 We had found that
a looped conformation of these AEA analogs is energet-
ically favorable and that a structural correlation be-
tween this low energy conformation and the classical
cannabinoids can be obtained with the superposition
of (1) the oxygen of the carboxamide with the pyran
oxygen in D9-THC, (2) the hydroxyl group of the etha-
nol with the phenolic hydroxyl group of D9-THC, (3)
the five terminal carbons and the pentyl side chain of
D9-THC, and (4) the polyolefin loop overlaying with
the cannabinoid tricyclic ring. Our studies further
showed that, when overlayed in this fashion, the poten-
cies of AEA analogs are predictable by QSAR. The abil-
ity to incorporate the pharmacological potency of these
AEA analogs into the cannabinoid pharmacophore
model is also shown to support the relevance of this
model. Preliminary molecular modeling studies of the
hybrid 1 with D9-THC, was carried out in collaboration
with Dr. Brian Thomas. An initial overlay between the
structures of O-2220 and D9-THC was obtained (see
Fig. 2) by the superposition of (i) the dimethylheptyl
side chain of the hybrid with the side chain of D9-
THC, (ii) oxygen of the ether of the hybrid with the pyr-
an oxygen of D9-THC, (iii) the terminal hydroxyl with
the phenolic oxygen of D9-THC, (iv) the chain with
the olefinic bonds with the alicyclic ring of D9-THC.
However, when aligning the ring system as shown for
In summary, these analogs showed an increase in bind-
ing affinity and improvement in the pharmacological
activity that is very similar to the results obtained with
THC side chain modified analogs.
4. Conclusion
The high receptor affinity and pharmacological potency
of O-2220 provides further insight into the structural
commonalities of THC and AEA that are required for
biological activity. Incorporation of additional struc-
tural constraints in AEA will be necessary to establish
its optimal conformation. However, the hybrids de-
scribed herein illustrate the potential for developing
new templates for cannabinoid receptor agonists and
antagonists.
5. Experimental
5.1. General
All reagents were of commercial quality, reagent grade,
and used without further purification. Anhydrous sol-
vents were purchased from Aldrich and used without
further purification. All reactions were carried out under
N2 atmosphere. Organic solutions were dried with

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C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
OH
O
R
O
Figure 2. Superposition of two conformers of O-2220 and D9-THC. In the top panel, an orthogonal projection of space-filled models show a single
conformation of O-2220 overlayed with D9-THC (in purple). The atoms in the O-2220 conformation are colored by atom type (oxygen red, carbons
white, hydrogens cyan, and nitrogens blue). D9-THC is also shown in the upper right hand corner with its atoms colored by atom type to help orient
the viewer to the overlay with D9-THC in purple. In the lower panel, a similar presentation of an additional conformation of O-2220 is presented.
Finally, the basis for the initial superposition is shown in black and white.
1
sodium sulfate. H NMR spectra were recorded on a
JEOL Eclipse 300 MHz spectrophotometer using CDCl3
as the solvent with tetramethylsilane as an internal stan-
dard. MS data were obtained on an Agilent 1100 LC/
MSD system. Thin-layer chromatography (TLC) was
carried out on Baker Si 250F plates and was developed
upon treatment with phosphomolybdic acid (PMA).
Flash column chromatography was carried out on EM
Science silica gel 60. Elemental analyses were performed
by Atlantic Microlab, Inc., Atlanta, GA, and were
found to be within 0.4% of calculated values for the
elements shown, unless otherwise noted.
5.2. tert-Butyl-but-3-ynyloxy-diphenylsilane (10)
Figure 3. Superposition of the side chains of D9-THC, O-2220, O–2294
and O–2243 based on the alignment described in Figure 2 for O–2220.
To a stirred solution of 3-butyn-1-ol (5.0 g, 0.071 mol) in
dry DMF (150 mL) at 0 ꢁC, was added imidazole (9.7 g,

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
7857
0.14 mol) and tert-butyldiphenylsilyl chloride (19.5 g,
0.072 mol) and the resulting solution was stirred over-
night. On completion, the reaction was diluted with
pad of silica to afford 10 g of 13 as a pale yellow oil in
70% yield. H NMR d 1.05 (s, 9H), 1.79 (quint., 2H,
J = 7.4 Hz), 2.16–2.25 (tt, 2H, J = 2.46, 6.87 Hz), 2.38–
2.46 (m,4H), 3.08 (t, 2H, J = 2.1 Hz), 3.66 (s, 3H), 3.75
(t, 2H, J = 7.29 Hz), 7.37–7.42 (m, 6H), 7.66–7.69 (m,
4H).
1
water
followed
by
extraction
with
EtOAc
(4 · 500 mL). The organic extracts were combined,
washed with brine, dried and concentrated in vacuo.
The residue was chromatographed on silica, eluting with
1% EtOAc–hexanes to afford 19.6 g of 10 as a oil in 90%
yield. 1H NMR d 1.05 (s, 9H), 1.92 (t, 1H, J = 2.76 Hz),
2.41–2.47 (dt, 2H, J = 2.73, 7.14 Hz), 3.78 (t, 2H,
J = 7.0 Hz), 7.34–7.41 (m, 6H), 7.66–7.71 (m, 4H).
5.6. 11-(tert-Butyldiphenylsilanyloxy)undeca-5,8-dienoic
methyl ester (14)
To a stirred solution of Ni(OAc)2 (10.9 g, 0.044 mol) in
EtOH (500 mL) saturated with H2 (g), was added
NaBH4 (1.66 g, 0.044 mol) in portions and the resulting
solution saturated with H2. To this was added ethylene-
diamine (3.71 mL, 0.055 mol) followed by a solution of
13 (10 g, 0.022 mol) in EtOH (50 mL), quickly maintain-
ing the H2 atmosphere after each addition. The reaction
progress was monitored by TLC and on completion in
1 h was quenched with Et2O (200 mL). The reaction
solution was then filtered through Celite pad under suc-
tion and the filtrate concentrated in vacuo. The residue
was filtered through a small pad of silica to give 8.22 g
5.3. 5-(tert-Butyl-diphenylsilanyloxy)pent-2-yn-1-ol (11)
Cuprous chloride (1.25 g, 0.0125 mol) was dissolved in
12% aqueous HCl (20 mL) to give a brown solution
which was cooled to 0 ꢁC. To this stirred solution,
40% KOH solution (20 mL) was added dropwise over
the course of an hour precipitating an orange solid. This
solid was filtered with suction and washed well with
water. The moist solid was subsequently added to a sus-
pension of 10 (17.8 g, 0.058 mol), CaCO3 (0.062 g,
0.0006 mol), H2O (1.25 mL) and 37% aq HCHO
(6.2 mL) and the suspension heated at 110 ꢁC. The reac-
tion was monitored by TLC for 5 days, cooled to room
temperature, diluted with EtOAc (800 mL), washed with
water and brine. The organic extracts were dried and
concentrated in vacuo to yield a brown residue which
was chromatographed on silica, eluting with 20%
EtOAc–hexanes to give 15.5 g of 11 in 79% yield as a
colorless oil. 1H NMR d 1.05 (s, 9H), 2.48 (tt, 2H,
J = 2.2, 7.14 Hz), 3.77 (t, 2H, J = 7.14 Hz), 4.19 (m,
2H), 7.35–7.45 (m, 6H), 7.65–7.7 (m, 4H).
1
of 14 as a colorless oil in 81% yield. H NMR d 1.05
(s, 9H), 1.68 (quint., 2H, J = 7.4 Hz), 2.01–2.11 (m,
2H), 2.27–2.36 (m, 4H), 2.72 (t, 2H, J = 5.5 Hz), 3.64
(s, 3H), 3.67 (m, 2H), 5.31–5.42 (m, 4H), 7.32–7.44 (m,
6H), 7.65–7.71 (m, 4H).
5.7. 11-Hydroxyundeca-5,8-dienoic methyl ester (15)
To a solution of 14 (5.9 g, 0.013 mol), glacial AcOH
(7.6 mL, 0.13 mol) in dry THF (70 mL), Bu4NF (1 M
in THF, 122.7 mL, 0.13 mol) was added dropwise and
reaction was stirred at room temperature. The reaction
was monitored by TLC and on completion the solvent
was removed in vacuo. The oily residue obtained was ex-
tracted into ether, washed with water and brine, dried,
concentrated and subjected to chromatographic purifi-
cation on a silica column. 2.5 g of 15 was obtained on
elution with 20% EtOAc–hexanes in 91% yield as a col-
orless oil. 1H NMR d 1.70 (quint., 2H, J = 7.4 Hz), 1.78
(br s, 1H), 2.07–2.15 (m, 2H), 2.28–2.38 (m, 4H), 2.81 (t,
2H, J = 5.76 Hz), 3.60–3.72 (m, 5H), 5.32–5.6 (m, 4H);
MS (CI, m/z): 213 [(M+H)+].
5.4. 5-(Bromopent-3-ynyloxy)-tert-butyl-diphenylsilane
(12)
To a stirred solution of 11 (14.6 g, 0.043 mol) in dry
ether (150 mL) at 0 ꢁC, was added CBr4 (43.1 g,
0.13 mol) followed by dropwise addition of trioctyl
phosphine (57.9 mL, 0.13 mol). The reaction was al-
lowed to warm to room temperature and progress of
the reaction was monitored by TLC. On completion
the solvent was removed in vacuo and the residue sub-
jected to column chromatography. On elution with
20% EtOAc–hexanes 15 g of 12 was obtained in 86%
5.8. 11-methanesulfonyloxy-undeca-5,8-dienoic methyl
ester (16)
1
yield as yellow oil. H NMR d 1.05 (s, 9H), 2.48–2.50
(tt, 2H, J = 2.3, 6.87 Hz), 3.76 (t, 2H, J = 6.87 Hz),
3.78 (t, 2H, J = 2.1 Hz), 7.37–7.45 (m, 6H), 7.66–7.69
(m, 4H); MS (CI, m/z): 401, 403 [M+].
To a stirred solution of 15 (2 g, 9.43 mmol) in dry
CH2Cl2 (40 mL) at 0 ꢁC was added Et3N (4 mL,
28.7 mmol) followed by dropwise addition of metha-
nesulfonyl chloride (1.1 mL, 14.2 mmol). The reaction
was allowed to warm to room temperature with stirring
and monitored by TLC. After three hours, the reaction
solution was diluted with CH2Cl2 (150 mL), washed
with water and brine, dried and concentrated in vacuo.
The crude orange oily mesylate 16 (2.5 g, 91%) obtained
was used as such in the next step without further purifi-
5.5. 11-(tert-Butyldiphenylsilanyloxy)undeca-5,8-diynoic
methyl ester (13)
A solution of 12 (8.68 g, 0.021 mol), K2CO3 (4.4 g,
0.032 mol), CuI (6.1 g, 0.032 mol), NaI (4.8 g,
0.032 mol) and methyl hex-5-ynoate (2.77 g, 0.022 mol)
in dry DMF (60 mL) was stirred overnight at room tem-
perature. On completion, the reaction mixture was di-
luted with EtOAc and filtered with suction to remove
the inorganic solids. The filtrate was subsequently
washed with water, brine and concentrated in vacuo.
The residue thus obtained was filtered through a small
1
cation. H NMR d 1.70 (quint., 2H, J = 7.4 Hz), 2.04–
2.14 (m, 2H), 2.33 (t, 2H, J = 7.4 Hz), 2.51–2.57 (q,
2H, J = 6.8 Hz), 2.81 (br t, 2H, J = 7.14 Hz), 3.01 (s,
3H), 3.67 (s, 3H), 4.23 (t, 2H, J = 6.7 Hz), 5.32–5.6 (m,
4H).

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C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
5.9. N,3-Dimethoxy-N-methylbenzamide (19)
To solution of 3-methoxybenzoic acid (10 g,
as quickly as possible while maintaining the tempera-
ture. The orange-brown solution obtained was stirred
vigorously at À50 ꢁC for one hour after which a solu-
tion of 21 (10 g, 0.045 mol) in dry CH2Cl2 (50 mL)
was added dropwise. The reaction solution was allowed
to stir for 2 h at À50 ꢁC, then allowed to reach À10 ꢁC
before quenching by addition of ice-cold saturated
NH4Cl solution dropwise. The aqueous layer was then
extracted with CH2Cl2 (5 · 200 mL), the organic
extracts washed with brine, dried and concentrated in
vacuo. The residue was purified by column chromatog-
raphy, eluting with 1% EtOAc–hexanes to afford 10.2 g
a
0.065 mol) in CH2Cl2 (70 mL) stirred at 0 ꢁC was added
DMF (0.8 mL) followed by oxalyl chloride (11.4 mL,
0.131 mol) dropwise. The reaction mixture was stirred
and after 3–4 h was cannulated into addition funnel
and added dropwise to a stirred solution of N,O-dim-
ethylhydroxylamine hydrochloride (63.4 g, 0.65 mol)
and Et3N (95.6 mL, 0.65 mol) in CH2Cl2 (170 mL).
The white heterogeneous mixture was left to stir vigor-
ously at room temperature overnight. Water (200 mL)
was added to the mixture followed by extraction with
CH2Cl2. The combined organic extracts were washed
with brine, dried and concentrated in vacuo. The resi-
due was purified by column chromatography, eluting
with 30% EtOAc–hexanes to give 38.1 g of the desired
1
of 23 in 95% yield as a colorless oil. H NMR d 0.84 (t,
3H, J = 6.87 Hz), 1.06 (br s, 2H), 1.14–1.24 (m, 6H),
1.27 (s, 6H), 1.54–1.6 (m, 2H), 3.80 (s, 3H), 6.68–6.75
(m, 1H), 6.87–6.93 (m, 2H), 7.22 (t, 1H, J = 7.8 Hz).
1
amide 19 in 81% yield. H NMR d 3.32 (s, 3H), 3.55
(s, 3H), 3.80 (s, 3H), 6.95–7.0 (m, 1H), 7.17–7.33 (m,
3H).
5.14. 1-(1,1-Dimethylheptyl)-4-methoxybenzene (24)
This was prepared from 22, TiCl4 and (CH3)2Zn in 25%
yield by similar procedure as described for 23. 1H NMR
d 0.81 (t, 3H, J = 7.14 Hz), 1.05 (br s, 2H), 1.12–1.21 (m,
6H), 1.24 (s, 6H), 1.54 (m, 2H), 3.78 (s, 3H), 6.84 (d, 2H,
J = 9.09 Hz), 7.23 (d, 2H, J = 8.79 Hz).
5.10. N,4-Dimethoxy-N-methylbenzamide (20)
This was prepared from p-anisic acid, oxalyl chloride,
and N,O-dimethylhydroxylamine hydrochloride in
quantitative yield by the same procedure as described
5.15. 3-(1,1-Dimethylheptyl)phenol 25
1
for 19. H NMR d 3.36 (s, 3H), 3.56 (s, 3H), 3.85 (s,
3H), 6.90 (d, 2H, J = 8.79 Hz), 7.73 (d, 2H, J = 8.79 Hz).
To a solution of BBr3 (1.0 M in CH2Cl2, 33.3 mL,
0.033 mol) cooled to 0 ꢁC was added a solution of 23
(6.9 g, 0.025 mol) in CH2Cl2 (100 mL) dropwise. The
reaction was allowed to stir overnight at room tempera-
ture. The reaction solution was cooled to 0 ꢁC and water
(50 mL) was added dropwise. The aqueous layer was
then extracted with EtOAc, the organic extracts com-
bined, dried and concentrated in vacuo. The residue ob-
tained was chromatographed on silica eluting with 3%
EtOAc–hexanes to give 4 g of 25 as a viscous oil in
5.11. 1-(3-Methoxyphenyl)heptan-1-one (21)
To a solution of 19 (9.5 g, 0.048 mol) in THF (40 mL)
was added dropwise a solution of hexylmagnesium bro-
mide (2.0 M in ether, 26.4 mL, 0.0528 mol) and the reac-
tion solution allowed to reflux for 6 h. After cooling to
room temperature, the reaction was quenched with sat-
urated NH4Cl solution followed by extraction with
EtOAc (4 · 100 mL). The organic extracts were com-
bined, washed with brine, dried and concentrated
in vacuo. The residue was purified by column chroma-
tography, eluting with 25% EtOAc–hexanes to afford
1
83% yield. H NMR d 0.84 (t, 3H, J = 6.6 Hz), 1.05
(br s, 2H), 1.14–1.22 (m, 6H), 1.25 (s, 6H), 1.52–1.57
(m, 2H), 6.60–6.65 (m, 1H), 6.81–6.90 (m, 2H), 7.15 (t,
1H, J = 7.8 Hz).
1
6.5 g of ketone 21 as a colorless oil in 61% yield. H
NMR d 0.90 (t, 3H, J = 6.87 Hz), 1.28–1.4 (m, 6H),
1.67–1.78 (quint., 2H, J = 7.14 Hz), 2.95 (t, 2H,
J = 7.41 Hz), 3.85 (s, 3H), 7.08–7.12 (m, 1H), 7.36 (t,
1H, J = 7.8 Hz), 7.48–7.56 (m, 2H).
5.16. 4-(1,1-Dimethylheptyl)phenol (26)
This was prepared from 24 using BBr3/CH2Cl2 in 95%
yield by the same procedure as described for 25. 1H
NMR d 0.81 (t, 3H, J = 7.14 Hz), 1.05 (br s, 2H),
1.12–1.21 (m, 6H), 1.24 (s, 6H), 1.54 (m, 2H), 6.84 (d,
2H, J = 9.09 Hz), 7.23 (d, 2H, J = 8.79 Hz).
5.12. 1-(4-Methoxyphenyl)heptan-1-one (22)
This was prepared from 20 in 89% yield by similar pro-
cedure as described for 21. 1H NMR d 0.90 (t, 3H,
J = 6.9 Hz), 1.23–1.43 (m, 6H), 1.67–1.76 (quint., 2H,
J = 7.14 Hz), 2.91 (t, 2H, J = 7.14 Hz), 3.87 (s, 3H),
6.93 (d, 2H, J = 9.06 Hz), 7.94 (d, 2H, J = 9.06 Hz).
5.17. 11-[3-(1,1-Dimethylheptyl)phenoxy]undeca-5,8-
dienoic acid methyl ester (27)
To a stirred solution of 25 (2.5 g, 11 mmol) and 16
(1.12 g, 3.8 mmol) in dry DMF (5 mL) was added
KOH (0.65 g, 11 mmol). The reaction solution was stir-
red at 50 ꢁC for 3 h and monitored by TLC. The reac-
tion was worked up by diluting with water followed by
extraction with EtOAc (5 · 100 mL). The organic ex-
tracts were washed with brine, dried and concentrated
in vacuo. The brown residue obtained was chromato-
graphed on silica eluting with 5% EtOAc–hexanes to
give 0.85 g of 27 as a viscous oil in 53% yield. 1H
5.13. 1-(1,1-Dimethylheptyl)-3-methoxybenzene (23)
A 1 M solution of TiCl4 in CH2Cl2 (30.4 mL, 0.27 mol)
was added to CH2Cl2 (125 mL) placed in a three-
necked RB flask, fitted with an addition funnel and
maintaining the temperature at À50 ꢁC under a steady
stream of N2. This was followed by addition of
(CH3)2Zn (13.5 mL, 0.27 mol) via the addition funnel

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
7859
NMR d 0.84 (t, 3H, J = 6.87 Hz), 1.05 (br s, 2H), 1.14–
1.22 (m, 6H), 1.26 (s, 6H), 1.52–1.59 (m, 2H), 1.73 (m,
2H), 2.10–2.22 (m, 2H), 2.3 (m, 2H), 2.58 (m, 2H),
2.83 (t, 2H, J = 5.76 Hz), 3.66 (s, 3H), 3.96 (t, 2H,
J = 6.8 Hz), 5.30–5.58 (m, 4H), 6.65–6.7 (m, 1H), 6.86–
6.92 (m, 2H), 7.2 (t, 1H, J = 7.8 Hz).
5.20. 11-[4-(1,1-Dimethylheptyl)phenoxy]undeca-5,8-die-
noic acid [R(1-hydroxypropan-2-yl)]-amide 2 (O-2294)
The corresponding acid was obtained from 28 as a yel-
low oil in 93% yield by the same procedure as described
for acid of 27. 1H NMR d 0.84 (t, 3H, J = 6.60 Hz), 1.04
(br s, 2H), 1.12–1.21 (m, 6H), 1.25 (s, 6H), 1.51–1.57 (m,
2H), 1.66–1.79 (m, 2H), 2.10–2.17 (m, 2H), 2.34–2.39
(m, 2H), 2.55 (q, 2H, J = 6.60, 5.49 Hz), 2.83 (t, 2H,
J = 5.49 Hz), 3.95 (t, 2H, J = 6.87 Hz), 5.38–5.51 (m,
4H), 6.83 (d, 2H, J = 8.79 Hz), 7.22 (d, 2H,
J = 8.79 Hz). Target 2 was obtained in 64% yield from
the above acid by similar procedure as described for 1.
1H NMR d 0.83 (t, 3H, J = 6.8 Hz), 1.05 (br s, 2H),
1.14–1.24 (m, 9H), 1.26 (s, 6H), 1.53–1.59 (m, 2H),
1.68–1.78 (quint., 2H, J = 7.41 Hz), 2.09–2.22 (m, 4H),
2.56 (q, 2H, J = 6.57, 5.52 Hz), 2.83 (t, 2H,
J = 5.5 Hz), 3.48–3.68 (m, 2H), 3.97 (t, 2H,
J = 6.87 Hz), 4.05–4.08 (m, 1H), 5.37–5.52 (m, 4H),
5.58 (br s, 1H), 6.81–6.84 (d, 2H, J = 6.87 Hz), 7.22 (d,
2H, J = 6.87 Hz), MS (CI, m/z): 458 [(M+H)+]. Anal.
Calcd for C29H47O3NÆ0.3 H2O: C, 75.21; H, 10.36; N,
3.02. Found: C, 75.09; H, 10.51; N, 3.02.
5.18. 11-[4-(1,1-Dimethylheptyl)phenoxy]undeca-5,8-dienoic
acid methyl ester (28)
This was obtained from 26 and 16 by a procedure
similar to 27 in 52% yield. 1H NMR d 0.83 (t, 3H,
J = 6.67 Hz), 1.04 (br s, 2H), 1.14–1.23 (m, 6H),
1.25 (s, 6H), 1.50–1.57 (m, 2H), 1.70 (m, 2H),
2.08–2.22 (m, 2H), 2.32 (t, 2H, J = 7.41 Hz), 2.52
(q, 2H, J = 6.87, 5.22 Hz), 2.82 (t, 2H, J = 5.52 Hz),
3.65 (s, 3H), 3.95 (t, 2H, J = 6.87 Hz), 5.31–5.54
(m, 4H), 6.82 (d, 2H, J = 8.79 Hz), 7.21 (d, 2H,
J = 8.79 Hz).
5.19. 11-[3-(1,1-Dimethylheptyl)phenoxy]undeca-5,8-dienoic
acid [R(1-hydroxypropan-2-yl)]-amide 1 (O-2220)
LiOH (0.171 g, 0.0042 mol) was added to a solution
of 27 (0.25 g, 0.0006 mol) in MeOH (18 mL) and
H2O (6 mL) and the reaction was left to stir over-
night at 50 ꢁC. On completion the reaction was
cooled to room temperature and the solution acidified
to pH 1.0 followed by extraction with ether. The or-
ganic extracts were dried and concentrated in vacuo
to yield 0.24 g of the corresponding acid as a yellow
5.21. 1-o-Tolylheptan-1-one (29)
This was prepared from o-toluic acid in 55% yield by the
same procedure as described for 21. H NMR d 0.88 (t,
3H, J = 6.3 Hz), 1.2–1.43 (m, 6H), 1.64–1.74 (m, 2H),
2.49 (s, 3H), 2.88 (t, 2H, J = 7.41 Hz), 7.23–7.26 (m,
2H), 7.3–7.41(m, 1H), 7.59–7.62 (m, 1H).
1
1
oil to be used without further purification. H NMR
d 0.82 (t, 3H, J = 6.87 Hz), 1.05 (br s, 2H), 1.14–1.22
(m, 6H), 1.26 (s, 6H), 1.57–1.75 (m, 4H), 2.08–2.18
(m, 2H), 2.24–2.32 (m, 2H), 2.50–2.58 (m, 2H), 2.87
(dt, 2H, J = 5.5 Hz), 3.97 (q, 2H, J = 6.6 Hz),
5.34–5.52 (m, 4H), 6.70–6.73 (m, 1H), 6.88–6.94 (m,
2H), 7.16 (t, 1H, J = 7.9 Hz), MS (CI, m/z): 401
[(M+H)+].
5.22. 1-(1,1-Dimethylheptyl)-2-methylbenzene (30)
This was prepared from 29 in 90% yield by the similar
1
procedure as described for 23. H NMR d 0.84 (t, 3H,
J = 6.87 Hz), 1.03 (br s, 2H), 1.19–1.28 (m, 6H), 1.37
(s, 6H), 1.71–1.76 (m, 2H), 2.49 (s, 3H), 7.09–7.16 (m,
3H), 7.25–7.30 (m, 1H).
Oxalyl chloride (0.155 g, 0.0012 mol) was added drop-
wise to a stirred solution of the above acid (0.24 g,
0.0006 mol) in benzene (2 mL) and DMF (1 drop) main-
tained at 0 ꢁC. The reaction mixture was stirred for 2 h
and the solvent was evaporated in vacuo and the flask
was left to dry on high vacuum for 1 h. The residue ob-
tained was dissolved in CH2Cl2 (2 mL), and added
dropwise to an ice-cooled flask containing (R)-2-amino
propanol (0.46 g, 0.006 mol) dissolved in CH2Cl2 and
cooled to 0 ꢁC. The reaction mixture was stirred over-
night. The solvent was removed in vacuo and the resi-
due chromatographed on silica eluting with CHCl3 to
afford 0.24 g of 1 as a yellow oil in 89% yield. 1H
NMR d 0.83 (t, 3H, J = 6.3 Hz), 1.05 (br s, 2H), 1.13–
1.18 (m, 9H), 1.26 (s, 6H), 1.53–1.59 (m, 2H), 1.68–
1.78 (m, 2H), 2.09–2.22 (m, 4H), 2.56 (q, 2H, J = 5.22,
7.14 Hz), 2.73–2.85 (dt, 2H, J = 5.22 Hz), 3.48–3.69
(m, 2H), 3.97 (t, 2H, J = 6.8 Hz), 4.05–4.08(m, 1H),
5.37–5.56 (m, 4H), 6.67–6.71 (m, 1H), 6.85–6.92 (m,
2H), 7.20 (br t, 1H, J = 7.98 Hz), MS (CI, m/z): 458
[(M+H)+]. Anal. Calcd for C29H47O3NÆ1.2 H2O: C,
72.67; H, 10.39; N, 2.92. Found: C, 72.68; H, 10.10;
N, 2.69.
5.23. 2-(1,1-Dimethylheptyl)benzaldehyde (31)
NBS (1.55 g, 0.0086 mol) was added to a solution of 30
(1.57 g, 0.0072 mol) in CCl4 (40 mL). Once the solid had
dissolved, AIBN (0.05 g, 0.0018 mol) was added and the
reaction mixture was refluxed overnight. The mixture
was then filtered through a plug of silica and solvent re-
moved in vacuo to yield 2.1 g of the benzyl bromide
1
derivative as a clear oil in quantitative yield. H NMR
d 0.83 (t, 3H, J = 6.87 Hz), 1.03 (br s, 2H), 1.18–1.3
(m, 6H), 1.4 (s, 6H), 1.71–1.76 (m, 2H), 4.81 (s, 2H),
7.18–7.3 (m, 3H), 7.41–7.46 (m, 1H). To a solution of
the benzyl bromide derivative (2 g, 0.007 mol) in CHCl3
(50 mL) was added (Bu4N)2Cr2O7 (9.9 g, 0.014 mol) and
the mixture refluxed overnight. Silica (20 g) was added
to the cooled reaction mixture and the solvent removed
in vacuo. The red residue was chromatographed on sil-
ica eluting with 1–5% EtOAc–hexanes to yield 1.43 g
1
of the aldehyde 31 in 87% yield. H NMR d 0.83 (t,
3H, J = 6.87 Hz), 1.03 (br s, 2H), 1.17–1.25 (s, 6H),
1.48 (s, 6H), 1.79–1.85 (m, 2H), 7.29–7.32 (t, 1H,
J = 7.4 Hz), 7.39 (d, 1H, J = 1.1 Hz), 7.45–7.51 (m,
1H), 7.88–7.92 (dd, 1H, J = 1.65, 6.1 Hz).

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C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
5.24. 11-Iodoundeca-5,8-dienoic acid methyl ester (32)
chromatography, eluting with CHCl3 to afford 3 in
quantitative yield. 1H NMR
0.83 (t, 2H,
d
To a stirred solution of 15 (2 g, 0.0094 mol), triphenyl-
phosphine (5 g, 0.019 mol) and imidazole (1.3 g,
0.019 mol) in dry CH3CN/Et2O 1:2 (16.7:33.3 mL) at
0 ꢁC was added I2 (4.8 g, 0.019 mol) in portions. The reac-
tion mixture was left to stir at room temperature for 1 h.
The mixture was diluted with pentane/ether (4:1) and fil-
tered through a silica plug. The colorless filtrate was dried
and concentrated in vacuo and the residue was chromato-
graphed on silica eluting with hexanes, then 20% EtOAc–
hexanes to give 2.7 g of 32 in 90% yield. 1H NMR d 1.71
(quint., 2H, J = 7.4 Hz), 2.05–2.14 (m, 2H), 2.30–2.35 (t,
2H, J = 7.56 Hz), 2.62–2.79 (m, 4H), 3.15 (t, 2H,
J = 7.14 Hz), 3.67 (s, 3H), 5.33–5.52 (m, 4H).
J = 6.87 Hz), 0.97 (br s, 2H), 1.12–1.21 (m, 9H), 1.34–
1.38 (m, 6H), 1.66–1.76 (m, 4H), 2.05 (m, 2H), 2.16 (t,
2H, J = 7.44 Hz), 2.68–2.99 (m, 4H), 2.95–3.02 (m,
2H), 3.48–3.69 (m, 2H), 4.07 (m, 1H), 5.30–5.8 (m,
5H), 6.81–6.84 (d, 1H, J = 10.98 Hz), 7.03–7.34 (m,
4H), MS (CI, m/z): 454 [(M+H)+]. Anal. Calcd for
C30H47O2NÆ1.1 H2O: C, 76.09; H, 10.47; N, 2.96.
Found: C, 76.03; H, 10.25; N, 2.96.
5.28. 1-(3-Methoxyphenyl)-5-phenoxypentan-1-one (35)
4-Bromophenoxybutane (10 g, 0.043 mol) and Mg pow-
der (1.4 g, 325 mesh, 0.058 mol) in 500 mL THF was re-
fluxed for 2 h. The reaction mixture was then cooled to
room temperature and 3-methoxybenzonitrile (3.54 g,
0.029 mol) was added and again refluxed for 2 h. The
imine formed was hydrolyzed with dropwise addition
of 6 N HCl (150 mL) to the reaction solution cooled in
ice-bath and reaction mixture was then refluxed over-
night. The solvent was removed in vacuo and saturated
NH4Cl solution (600 mL) added. The aqueous layer was
extracted with EtOAc (4 · 200 mL), organic extracts
were combined, dried and concentrated in vacuo. The
residue was purified by column chromatography, eluting
with 10% EtOAc–hexanes to yield 8 g of 35 in 64% yield
5.25. 11-Triphenylphosphoniumiodide-undeca-5,8-dienoic
acid methyl ester (33)
A solution of 32 (2.7 g, 0.08 mol) and triphenylphosphine
(2.4 g, 0.009 mol) in dry CH3CN (50 mL) was refluxed
overnight. The solvent was removed in vacuo and the vis-
cous residue was purified by washing and decanting
repeatedly with hexanes and benzene until most of the ex-
cess triphenylphosphine was removed. The viscous resi-
due was dried in a vacuum oven for 24 h at 50 ꢁC to
1
give 4.2 g of 33 as a pale yellow gum in 90% yield. H
1
NMR d 1.57–1.67 (m, 2H), 1.95 (q, 2H, J = 7.00 Hz),
2.25 (t, 2H, J = 7.41 Hz), 2.42–2.52 (m, 2H), 2.56 (t,
2H, J = 7.00 Hz), 3.63 (s, 3H), 3.81–3.90 (m, 2H), 5.18–
5.66 (m, 4H), 7.25–7.36 (m, 6H), 7.78–7.94 (m, 9H).
as a white crystalline solid. H NMR d 1.88–1.98 (m,
4H), 3.04 (t, 2H, J = 7.14 Hz), 3.84 (s, 6H), 4.0 (t, 2H,
J = 5.77 Hz), 6.86–6.95 (m, 3H), 7.08–7.12 (dd, 1H,
J = 2.9 Hz), 7.23–7.30 (m, 2H), 7.36 (t, 1H,
J = 7.95 Hz), 7.48–7.55 (m, 2H), MS (CI, m/z): 285
[(M+H)+].
5.26. 12-[2-(1,1-Dimethylheptyl)phenyl]dodeca-5,8,11-tri-
enoic acid methyl ester (34)
5.29. 3-(5-Phenoxy-1,1-dimethylpentyl)-methoxyphenol (36)
To a stirring THF/HMPA solution (62 mL/8 mL) of 33
(3.78 g, 6.2 mmol) at À30 ꢁC, was added NHMDS
(6.5 mL, 6.2 mmol, 1 M in THF). The fluorescent red
mixture was then allowed to warm to 0 ꢁC. After
20 min the mixture was cooled to À78 ꢁC and the alde-
hyde 31 (1.4 g, 6.0 mmol) dissolved in THF (30 mL) was
added dropwise. The reaction mixture was warmed to
room temperature and refluxed overnight. The mud
brown mixture was diluted with hexanes (100 mL) and
filtered through a plug of silica. The solvent was re-
moved in vacuo and the residue was chromatographed
on silica eluting with 5% EtOAc–hexanes to afford
This was prepared from ketone 35 in 60% yield in a pro-
cedure similar to 23. 1H NMR d 1.18–1.25 (m, 2H), 1.29
(s, 6H), 1.62–1.68 (m, 4H), 3.80 (s, 3H), 3.84 (t, 2H,
J = 6.6 Hz), 6.7 (m, 1H), 6.80–6.95 (m, 5H), 7.25 (t,
3H, J = 7.95 Hz), MS (CI, m/z): 299 [(M+H)+].
5.30. 3-(5-Bromo-1,1-dimethylpentyl)phenol (37)
This was prepared from 36 using BBr3/CH2Cl2 in 93%
yield by the same procedure as described for 25. 1H
NMR d 1.20 (m, 2H), 1.28 (s, 6H), 1.56–1.62 (m, 2H),
1.75 (quint., 2H, J = 7.41 Hz), 3.32 (t, 2H,
J = 6.87 Hz), 4.69 (br s, 1H), 6.62–6.66 (m, 1H), 6.80
(t, 1H, J = 2.2 Hz), 6.87–6.91 (m, 1H), 7.17 (t, 1H,
J = 7.95 Hz).
1
1.3 g of 34 as a viscous oil in 50% yield. H NMR d
0.83 (t, 2H, J = 6.87 Hz), 0.97 (br s, 2H), 1.17–1.26 (m,
6H), 1.36 (s, 6H), 1.66–1.75 (m, 2H), 2.04–2.13 (m,
2H), 2.26–2.35 (m, 4H), 2.67–2.99 (m, 4H), 3.66 (s,
3H), 5.31–5.82 (m, 5H), 6.82 (d, 1H, J = 10.98 Hz),
7.02–7.38 (m, 4H), MS (CI, m/z): 411 [(M+H)+].
5.31. 3-(5-Hydroxy-1,1-dimethylpentyl)phenol (38)
5.27. 12-[2-(1,1-Dimethylheptyl)phenyl]dodeca-5,8,11-tri-
enoic acid [R-(1-hydroxypropan-2-yl)]-amide 3 (O-2243)
A solution of compound 37 (3.36 g, 0.012 mol) in 20%
aqueous HMPA solution (70 mL) was stirred overnight
at 110 ꢁC. The reaction mixture was cooled to room
temperature, diluted with water (150 mL) followed by
extraction with EtOAc. The organic extracts were com-
bined, dried and concentrated in vacuo. The residue was
purified by column chromatography, eluting with 15–
40% EtOAc–hexanes. The residue was subjected to col-
umn chromatography on silica to afford 1.8 g of 38 as a
A mixture of compound 34 (0.1 g, 0.26 mmol), NaCN
(0.0013 g, 0.026 mmol) and (R)-2-aminopropan-1-ol
(0.2 g, 2.6 mmol) in methanol (4 mL) was heated for
48 h in a sealed glass vial at 60 ꢁC. The reaction progress
was monitored by TLC and on completion was evapo-
rated to dryness. The residue was purified by column

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
7861
yellow oil in 70% yield. 1H NMR d 1.12 (m, 2H), 1.26 (s,
6H), 1.48 (quint., 2H, J = 7.14 Hz), 1.56–1.62 (m, 2H),
3.58 (t, 2H, J = 6.45 Hz), 5.79 (br s, 1H), 6.62–6.65 (m,
1H), 6.80 (t, 1H, J = 2.1 Hz), 6.88 (m, 1H), 7.15 (t,
1H, J = 7.98 Hz), MS (CI, m/z): 207 [(MÀH)+].
(0.12 mL, 0.21 mmol) and reaction mixture stirred over-
night. On completion, the reaction solution was diluted
with water followed by extraction with ether. The organ-
ic extracts were combined, dried and concentrated in va-
cuo. The residue was purified through flash column
chromatography on silica and 0.07 g of 4 was obtained
as a yellow oil on elution with 2% MeOH–EtOAc in
5.32. 3-[5-(tert-Butyldimethylsilanyloxy)-1,1-dimethyl-
pentyl]phenol (39)
1
73% yield. H NMR d 1.08–1.17 (m, 5H), 1.28 (s, 6H),
1.47 (m, 2H), 1.58–1.63 (m, 2H), 1.69–1.76 (m, 2H),
2.07–2.2 (m, 4H), 2.53–2.59 (m, 2H), 2.83 (t, 2H,
J = 5.35 Hz), 3.48–3.67 (m, 4H), 3.97 (t, 2H,
J = 6.87 Hz), 4.06 (s, 1H), 5.35–5.54 (m, 4H), 5.63 (s,
1H), 6.68–6.92 (m, 1H), 6.87–6.92 (m, 2H), 7.21 (t,
1H, J = 7.95 Hz), MS (CI, m/z): 446 [(M+H)+]. Anal.
Calcd for C27H43O4NÆ0.2 C4H8O2: C, 72.08; H, 9.70;
N, 3.02. Found: C, 71.97; H, 9.96; N, 3.01.
To the phenol 38 (0.11 g, 0.53 mmol) dissolved in DMF
(10 mL), was added imidazole (0.09 g, 1.4 mmol) and
the reaction solution was cooled to 0 ꢁC. To this
was added tert-butyldimethylsilyl chloride (0.088 g,
0.53 mmol) and the reaction mixture was stirred for
7 h. The reaction was then diluted with water followed
by extraction with EtOAc (4 · 50 mL). The organic ex-
tracts were combined, dried and concentrated. The resi-
due was purified by column chromatography, eluting
with 5–10% EtOAc–hexanes to give 0.1 g of the desired
5.35. 11-[3-(5-Hydroxy-1,1-dimethylpentyl)phen-
oxy]undeca-5,8-dienoic acid methyl ester (41)
1
product 39 in 55% yield. H NMR d 0.009 (s, 6H), 0.85
(s, 9H), 1.10 (m, 2H), 1.25 (s, 6H), 1.42 (quint., 2H,
J = 7.14 Hz), 1.52–1.58 (m, 2H), 3.52 (t, 2H,
J = 6.6 Hz), 4.93 (br s, 1H), 6.59–6.63 (m, 1H), 6.78 (t,
1H, J = 2.2 Hz), 6.75 (m, 1H), 7.14 (t, 1H, J = 7.95 Hz),
MS (CI, m/z): 323 [(M+H)+].
This was obtained from 40 as a yellow oil by a proce-
dure as described for 4 in 65% yield. H NMR d 1.12
1
(m, 2H), 1.28 (s, 6H), 1.47 (m, 2H), 1.58–1.63 (m, 2H),
1.68–1.75 (m, 2H), 2.04–2.16 (m, 2H), 2.32 (t, 2H,
J = 7.41 Hz), 2.53–2.60 (m, 2H), 2.83 (br t, 2H,
J = 5.22 Hz), 3.56 (t, 2H, J = 6.6 Hz), 3.65 (s, 3H),
3.96 (t, 2H, J = 6.87 Hz), 5.32–5.58 (m, 4H), 6.69–6.71
(m, 1H), 6.85–6.92 (m, 2H), 7.21 (t, 1H, J = 7.96 Hz),
MS (CI, m/z): 403 [(M+H)+].
5.33. 11-[3-(5-tert-Butyldimethylsiloxy-1,1-dimethylpen-
tyl)phenoxy]undeca-5,8-dienoic acid methyl ester (40)
Compound 40 was prepared from 16 and 39 by the same
procedure as described for 27 as a yellow oil in 62%
yield. H NMR d 0.0 (s, 6H), 0.85 (s, 9H), 1.08 (m,
5.36. 11-[3-(5-Azido-1,1-dimethylpentyl)phenoxy]undeca-
5,8-dienoic acid methyl ester (42)
1
2H), 1.27 (s, 6H), 1.42 (quint. 2H, 7.14 Hz), 1.58 (m,
2H), 1.66–1.75 (m, 2H), 2.08–2.15 (m, 2H), 2.32 (t,
2H, J = 7.41 Hz), 2.53–2.59 (m, 2H), 2.83 (t, 2H,
J = 5.5 Hz), 3.52 (t, 2H, J = 6.87 Hz), 3.66 (s, 3H),
3.96 (t, 2H, J = 6.87 Hz), 5.35–5.51 (m, 4H), 6.68–6.71
(m, 1H), 6.86–6.92 (m, 2H), 7.19 (t, 1H, J = 7.95 Hz),
MS (CI, m/z): 517 [(M+H)+].
Methanesulfonyl chloride (0.15 mL, 1.9 mmol) was
added dropwise to a solution of compound 41 (0.52 g,
1.3 mmol) and Et3N (0.54 mL, 3.9 mmol) dissolved in
CH2Cl2 (10 mL) and the reaction solution was cooled
to 0 ꢁC. The reaction was stirred for 3 h and allowed
to reach room temperature. On completion, the reaction
mixture was diluted with water (30 mL) followed by
extraction with CH2Cl2. The organic extracts were com-
bined, washed with brine, dried and concentrated to
yield 0.62 g of the crude mesylate in quantitative yield.
The mesylate was subsequently dried over vacuum and
dissolved in anhydrous DMF (10 mL). NaN3 (0.25 g,
3.8 mmol) was subsequently added and the reaction pro-
gress monitored by TLC. After 4 h, the reaction mixture
was partitioned between water and ether. The organic
layer was washed with brine, dried and concentrated
5.34. 11-[3-(5-Hydroxy-1,1-dimethylpentyl)phenoxy]-
undeca-5,8-dienoic acid [R-(1-hydroxypropan-2-yl)]amide
4 (O-2760)
A mixture of compound 40 (0.043 g, 0.083 mmol),
NaCN (1 mg, 0.016 mmol) and (R)-2-aminopropan-1-
ol (0.06 mL, 0.083 mmol) in methanol (3 mL) was
heated for 48 h in a sealed glass vial at 60 ꢁC. The reac-
tion progress was monitored by TLC and on completion
was evaporated to dryness. The residue was purified by
column chromatography, eluting with 50% EtOAc–hex-
anes and 120 mg of the desired amide derivative was ob-
1
to yield 0.48 g of 42 in 88% yield. H NMR d 1.13 (m,
2H), 1.28 (s, 6H), 1.5 (m, 2H), 1.58–1.62 (m, 2H),
1.68–1.73 (m, 2H), 2.05–2.15 (m, 2H), 2.32 (t, 2H,
J = 7.41 Hz), 2.54–2.59 (m, 2H), 2.83 (br t, 2H,
J = 5.76 Hz), 3.18 (t, 2H, J = 7.0 Hz), 3.64 (s, 3H),
3.97 (t, 2H, J = 6.87 Hz), 5.32–5.52 (m, 4H), 6.69–6.72
(m, 1H), 6.86–6.92 (m, 2H), 7.21 (t, 1H, J = 7.98 Hz),
MS (CI, m/z): 428 [(M+H)+].
1
tained as a colorless oil in 64% yield. H NMR d 0.0 (s,
6H), 0.86 (s, 9H), 1.1 (m, 2H), 1.16 (d, 3H, J = 6.87 Hz),
1.26 (s, 6H), 1.42 (m, 2H), 1.58 (m, 2H), 1.70–1.75 (m,
2H), 2.1–2.2 (m, 4H), 2.55–2.63 (m, 2H), 2.83 (m, 2H),
3.51 (t, 4H, J = 6.6 Hz), 3.96 (t, 2H, J = 6.87 Hz), 4.07
(m, 1H), 5.35–5.52 (m, 4H), 5.58 (br s, 1H), 6.69–6.71
(m, 1H), 6.86–6.92 (m, 2H), 7.19 (t, 1H, J = 7.98 Hz),
MS (CI, m/z): 560 [(M+H)+]. Tetrabutylammonium
fluoride (2.15 mL, 1 M in THF, 0.21 mmol) was added
dropwise to a solution of amide derivative (0.12 g,
0.21 mmol) in THF (10 mL), followed by AcOH
5.37. 11-[3-(5-Bromo-1,1-dimethylpentyl)phen-
oxy]undeca-5,8-dienoic acid methyl ester (43)
Thebromide43was obtainedin 88%yieldfrom 41asacol-
ored oil by a procedure similar to that described for 12. 1H

7862
C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
NMR d 1.18–1.29 (m, 8H), 1.57–1.62 (m, 2H), 1.70–1.81
(m, 4H), 2.06–2.15 (m, 2H), 2.28–2.38 (m, 2H), 2.53–2.63
(m, 2H), 2.83 (br t, 2H, J = 5.76 Hz), 3.32 (t, 2H,
J = 6.87 Hz), 3.67 (s, 3H), 3.92–3.99 (m, 2H), 5.35–5.6
(m, 4H), 6.68–6.73 (m, 1H), 6.86–6.92 (m, 2H), 7.21 (t,
1H, J = 7.98 Hz), MS (CI, m/z): 465, 467 [M+].
5.40. 11-[3-(5-Azido-1,1-dimethylpentyl)phenoxy]undeca-
5,8-dienoic acid [R-(1-hydroxypropan-2-yl)]-amide 6 (O-
2781)
The acid was obtained as an oily residue in 95% yield
from 42 by a procedure similar to that described for acid
1
of 1. H NMR d 1.08–1.15 (m, 2H), 1.28 (s, 6H), 1.45–
5.38. 11-[3-(5-Cyano-1,1-dimethylpentyl)phenoxy]-
undeca-5,8-dienoic acid methyl ester (44)
1.52 (m, 2H), 1.57–1.63 (m, 2H), 1.69–1.74 (m, 2H),
2.09–2.17 (m, 2H), 2.36 (t, 2H, J = 7.42 Hz), 2.54–2.60
(m, 2H), 2.84 (br t, 2H, J = 5.5 Hz), 3.17 (t, 2H,
J = 6.87 Hz), 3.97 (t, 2H, J = 6.84 Hz), 5.35–5.54 (m,
4H), 6.69–6.72 (m, 1H), 6.86–6.94 (m, 2H), 7.21 (t,
1H, J = 7.98 Hz), MS (CI, m/z): 414 [(M+H)+].
The bromide 43 (0.36 g, 0.8 mmol) was dissolved in 8 mL
anhydrous DMSO followed by the addition of NaCN
(0.14 g, 2.9 mmol) and the reaction progress was moni-
tored by TLC. After 4 h at 50 ꢁC, the reaction mixture
was diluted with water followed by extraction with
EtOAc. The organic extracts were combined, washed with
brine, dried and concentrated in vacuo. The residue was
purified by flash column and 0.2 g of 44 was obtained
on elution with 15% EtOAc–hexanes in 65% yield as a col-
Compound 6 was obtained as a yellow oil in 80% yield
from the acid by the procedure as described for 5 H
1
NMR d 1.08–1.18 (m, 5H), 1.28 (s, 6H), 1.45–1.52 (m,
2H), 1.57–1.63 (m, 2H), 1.68–1.76 (m, 2H), 2.05–2.22
(m, 4H), 2.54–2.60 (m, 2H), 2.76–2.86 (m, 2H), 3.18 (t,
2H, J = 7.0 Hz), 3.48–3.56 (m, 1H), 3.63–3.67 (m, 1H),
3.97 (t, 2H, J = 6.87 Hz), 4.03–4.09 (m, 1H), 5.34–5.56
(m, 5H), 6.69–6.73 (m, 1H), 6.86–6.92 (m, 2H), 7.21 (t,
1H, J = 7.95 Hz), MS (CI, m/z): 471 [(M+H)+]. Anal.
Calcd for C27H42O3N4Æ0.3 H2O: C, 68.12; H, 9.02; N,
11.77. Found: C, 68.15; H, 9.18; N, 11.79.
1
orless oil. H NMR d 1.16–1.32 (m, 8H), 1.51–1.63 (m,
4H), 1.68–1.76 (m, 2H), 2.06–2.15 (m, 2H), 2.23–2.35
(m, 4H), 2.54–2.64 (m, 2H), 2.83 (br t, 2H, J = 5.5 Hz),
3.66 (s, 3H), 3.92–3.99 (m, 2H), 5.35–5.54 (m, 4H),
6.70–6.73 (m, 1H), 6.85–6.91 (m, 2H), 7.21 (t, 1H,
J = 7.98 Hz), MS (CI, m/z): 412 [(M+H)+].
5.39. 11-[3-(5-Bromo-1,1-dimethylpentyl)phenoxy]-
undeca-5,8-dienoic acid [R-(1-hydroxypropan-2-yl)]-
amide 5 (O-2874)
5.41. 11-[3-(5-Cyano-1,1-dimethylpentyl)phenoxy]-
undeca-5,8-dienoic acid [R-(1-hydroxypropan-2-yl)]-amide
7 (O-2852)
The acid was obtained as an oily residue in 82% yield
from 43 by a procedure similar to that described for acid
of 1 except the reaction was performed at room temper-
The acid was obtained in 96% yield as a colorless oil from
44 by similar procedure as described for acid of 1 except
1
the reaction was performed at room temperature. H
1
ature in this case. H NMR d 1.12–1.34 (m, 8H), 1.56–
NMR d 1.15–1.33 (m, 8H), 1.57–1.62 (m, 2H), 1.69–
1.80 (m, 4H), 2.06–2.18 (m, 2H), 2.32–2.39 (m, 2H),
2.53–2.60 (m, 2H), 2.84 (br t, 2H, J = 5.49 Hz), 3.32 (t,
2H, J = 7.00 Hz), 3.92–3.99 (q, 2H, J = 6.84 Hz), 5.34–
5.52 (m, 4H), 6.68–6.72 (m, 1H), 6.86–6.91 (m, 2H),
7.21 (t, 1H, J = 7.96 Hz), MS (CI, m/z): 398 [(M+H)+].
1.62 (m, 2H), 1.69–1.80 (m, 4H), 2.07–2.18 (m, 2H),
2.34–2.39 (m, 2H), 2.51–2.64 (m, 2H), 2.84 (br t, 2H,
J = 5.5 Hz), 3.32 (t, 2H, J = 6.87 Hz), 3.92–3.99 (t, 2H,
J = 6.85 Hz), 5.36–5.53 (m, 4H), 6.68–6.72 (m, 1H),
6.86–6.92 (m, 2H), 7.21 (t, 1H, J = 7.98 Hz), MS (CI,
m/z): 451, 453 [M+].
Compound 7 was obtained in 62% yield as a pale yellow
1
Ethylchloroformate (0.15 mL, 1.6 mmol) was added
dropwise to a stirred solution of the above acid
(0.29 g, 0.6 mmol) and triethylamine (0.26 mL,
1.8 mmol) in CH2Cl2 (5 mL) maintained at 0 ꢁC. The
reaction mixture was stirred for 3 h after which (R)-2-
aminopropan-1-ol (0.14 mL, 1.8 mmol) dissolved in
CH2Cl2 was added dropwise. The reaction mixture
was stirred overnight. To the reaction mixture was
added 10% HCl followed by extraction with EtOAc.
The organic extracts were combined, washed with brine,
dried and concentrated in vacuo. The residue was chro-
matographed on silica eluting with 50% EtOAc–hexanes
oil by similar procedure as described for 5. H NMR d
1.15–1.26 (m, 5H), 1.29 (s, 6H), 1.50–1.63 (m, 4H),
1.67–1.77 (m, 2H), 2.06–2.28 (m, 6H), 2.54–2.60 (m,
2H), 2.75–2.85 (m, 2H), 3.48–3.55 (m, 1H), 3.63–3.66
(m, 1H), 3.97 (t, 2H, J = 6.87 Hz), 4.02–4.08 (m, 1H),
5.34–5.60 (m, 5H), 6.69–6.73 (m, 1H), 6.85–6.91 (m,
2H), 7.22 (t, 1H, J = 7.95 Hz), MS (CI, m/z): 455
[(M+H)+]. Anal. Calcd for C28H42O3N2Æ0.2 H2O: C,
73.39; H, 9.33; N, 6.11. Found: C, 73.41; H, 9.50; N, 6.05.
5.42. (5Z,8Z,11Z)-N-((R)-1-hydroxypropan-2-yl)-14-(3-
(2-methyloctan-2-yl)phenoxy)tetradeca-5,8,11-trienamide
8 (O-2655)
1
to yield 0.156 g of 5 as a yellow oil in 48% yield. H
NMR d 1.15–1.25 (m, 5H), 1.28 (s, 6H), 1.57–1.62 (m,
2H), 1.70–1.78 (m, 4H), 2.04–2.22 (m, 4H), 2.53–2.60
(m, 2H), 2.74–2.86 (m, 2H), 3.32 (t, 2H, J = 7.0 Hz),
3.48–3.56 (m, 1H), 3.63–3.67 (m, 1H), 3.95 (q, 2H,
J = 6.7 Hz), 4.02–4.10 (m, 1H), 5.32–5.57 (m, 5H),
6.69–6.72 (m, 1H), 6.86–6.92 (m, 2H), 7.21 (t, 1H,
J = 7.95 Hz), MS (CI, m/z): 508, 510 [M+]. Anal. Calcd
for C27H42O3NBrÆ0.3 H2O: C, 63.10; H, 8.35; N, 2.73.
Found: C, 63.17; H, 8.54; N, 2.97.
The alcohol 4529 was converted into the corresponding
mesylate in 73% yield by similar procedure as described
for 16. H NMR d 1.30 (m, 2H), 1.68–1.73 (m, 2H),
1
2.08–2.16 (m, 3H), 2.30–2.33 (m, 2H), 2.50 (m, 1H),
2.79–2.90 (m, 2H), 3.01 (s, 3H), 3.68 (s, 3H), 4.21 (t,
2H, J = 6.6 Hz), 5.29–5.58 (m, 6H). Compound 46 was
prepared from mesylate of 45 and 25 by using the same
1
procedure as described for 27 in 53% yield. H NMR d

C. Bourne et al. / Bioorg. Med. Chem. 15 (2007) 7850–7864
7863
0.84 (t, 3H, J = 6.87 Hz), 1.05 (br s, 2H), 1.14–1.22 (m,
6H), 1.26 (s, 6H), 1.52–1.59 (m, 2H), 1.73 (m, 2H),
2.10–2.22 (m, 4H), 2.3 (m, 2H), 2.58 (m, 2H), 2.83 (m,
2H), 3.66 (s, 3H), 3.96 (m, 2H), 5.30–5.58 (m, 6H),
6.65–6.7 (m, 1H), 6.86–6.92 (m, 2H), 7.2 (t, 1H,
J = 7.9 Hz); MS (CI, m/z): 455 [(M+H)+]. The acid 47
was obtained in 60% yield by similar procedure as de-
scribed for acid of 1. 1H NMR d 0.82 (t, 3H,
J = 6.87 Hz), 1.05 (br s, 2H), 1.14–1.22 (m, 6H), 1.26
(s, 6H), 1.57–1.75 (m, 4H), 2.08–2.18 (m, 4 H), 2.30–
2.36 (m, 2H), 2.50–2.58 (m, 2H), 2.87 (dt, 2H,
J = 5.5 Hz), 3.97 (m, 2H), 5.34–5.52 (m, 6H), 6.68–6.71
(m, 1H), 6.88–6.94 (m, 2H), 7.16 (t, 1H, J = 7.9 Hz),
MS (CI, m/z): 441 [(M+H)+]. Target 8 was obtained in
1 mM CP55,940. The assay was incubated at 30 ꢁC for
1 h and terminated by addition of ice-cold 50 mM
Tris–HCl containing bovine serum albumin (1 mg/mL)
(pH 7.4) followed by filtration under vacuum through
Whatman GF/B glass fiber filters with three washes with
cold Tris buffer. Bound radioactivity was determined by
liquid scintillation spectrophotometry at 50% efficiency
after extraction by shaking samples for 30–60 min with
Budget-Solve scintillation fluid. Data are reported as
meanS SEM of three experiments, each performed in
triplicate. Ki values were calculated from displacement
data using Equilibrium Binding Data Analysis (BIO-
SOFT, Milltown, NJ).
1
75% yield by similar procedure as described for 5. H
5.46. Behavioral evaluations
NMR d 0.83 (t, 3H, J = 6.3 Hz), 1.05 (br s, 2H), 1.13–
1.18 (m, 9H), 1.21 (s, 6H), 1.26 (m, 1H), 1.53–1.59 (m,
2H), 1.68–1.78 (m, 2H), 2.09–2.22 (m, 4H), 2.56 (m,
2H), 2.73–2.85 (m, 3H), 3.54–3.71 (m, 2H), 3.97 (m,
2H), 4.05–4.08 (m, 1H), 5.37–5.56 (m, 6.5H), 6.67–6.71
(m, 1H), 6.85–6.92 (m, 2H), 7.20 (t, 1H, J = 7.98 Hz),
MS (CI, m/z): 498 [(M+H)+]. Anal. Calcd for
C32H51O3NÆ0.3 H2O: C, 76.39; H, 10.34; N, 2.78.
Found: C, 76.38; H, 10.59; N, 2.92.
All mice were acclimated to the laboratory overnight.
Each mouse was tested in two of the tetrad assays: loco-
motor activity and tail flick or rectal temperature and
ring immobility. Prior to injection, baseline latency in
the tail flick test was measured in mice in the first group.
This procedure involved placing the mouse’s tail on an
ambient heat source (i.e., bright light) and recording la-
tency (in seconds) for tail removal. Typical control
latencies were 2–4 s. A 10-s maximal latency was used
in order to avoid damage to the mouse’s tail. After mea-
surement of baseline tail flick latency, mice were injected
iv with vehicle or drug. Four minUTES later they were
re-tested in the tail flick procedure. Immediately thereaf-
ter, the mice were placed into individual photocell activ-
ity cages (11 · 6.5 in.) for assessment of spontaneous
activity. For the next 10 min the total number of beam
interruptions in the 16 photocell beams/cage was re-
corded using a Digiscan Animal Activity Monitor
(Omnitech Electronics Inc., Columbus, OH). Spontane-
ous activity was expressed as percent of the control
(vehicle) group’s activity. Antinociception was expressed
as the percent maximum possible effect (MPE) using a
10-s maximum test latency as described earlier. Each
dose tested in the antinociception and hypomotility as-
says represents one group of animals (6 mice/group).
Cannabinoid-induced hypothermia and immobility were
determined in a separate group of animals. Prior to vehi-
cle or drug administration, rectal temperature was deter-
mined by a thermistor probe (inserted 25 mm) and a
telethermometer (Yellow Springs Instrument Co., Yel-
low Springs, OH). Four minutes after the i.v. injection
of the drug, body temperature was measured again.
The difference between pre- and postinjection rectal tem-
peratures was calculated as change in body temperature.
Immediately after measurement of body temperature,
the mice were placed on a 5.5-cm ring attached at a
height of 16 cm to a ring stand, and the amount of time
the animals remained motionless during a 5-min period
was recorded. The time that each animal remained
motionless on the ring was divided by 300 s and multi-
plied by 100 to obtain a percent immobility rating.
5.43. Drug preparation and administration
For binding assays, the compounds were prepared as
1 mg/mL stock solutions in absolute ethanol and were
stored at À20 ꢁC. For behavioral assays, drugs were dis-
solved in a 1:1:18 mixture of ethanol, emulphor (GAF
Corp., Linden, NJ), and saline (0.9% NaCl) and were
administered intravenously (iv) in the mouse tail vein
in volumes of 0.1 mL/10 g of body weight.
5.44. Membrane preparations
HEK-293 cells stably expressing the human CB1 recep-
tor were cultured in DMEM with 10% FBS and Chinese
Hamster Ovary (CHO) cells stably expressing the hu-
man CB2 receptor were cultured in DMEM with 10%
FCS. Cells were harvested by replacement of the media
with cold phosphate-buffered saline containing
1
mM EDTA followed by centrifugation at 1000g for
5 min at 4 ꢁC. The pellet was resuspended in 50 mM
Tris–HCl containing 320 mM sucrose, 2 mM EDTA
and 5 mM MgCl2 (pH 7.4) (centrifugation buffer), then
centrifuged at 100g for 10 min at 4 ꢁC and the resulting
supernatant was saved. This process was repeated twice.
The supernatant fractions were combined and centri-
fuged at 40,000g for 30 min at 4 ꢁC. The resulting P2
pellet was resuspended in assay buffer (50 mM Tris–
HCl (pH 7.4), 3 mM MgCl2, 0.2 mM EGTA, and
100 mM NaCl) and protein was measured. Membranes
were stored at À80 ꢁC until use.
5.45. Receptor binding
Membrane homogenates (50 lg) were incubated with
0.5 nM [3H]CP55,940 in the presence of varying concen-
trations (1 nM– 10 lM) of test compounds in 0.5 mL of
buffer containing bovine serum albumin (5 mg/mL).
Non-specific binding was measured in the presence of
5.47. Data analysis
Based on data obtained from numerous previous in vivo
studies with cannabinoids, maximal cannabinoid effects
in each in vivo pharmacological procedure were esti-

7864
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