Design, synthesis, and structure-activity relationship of novel opioid κ-agonists

Article abstract of DOI:10.1016/j.bmc.2008.09.011

By focusing on 4,5-epoxymorphinan, a traditional opioid skeleton but a new structure in the opioid κ-agonist research field, and by rationally applying the 'message-address concept' and 'accessory site hypothesis,' we discovered a new chemical class opioid κ-agonist, TRK-820 (1). Its development as an antipruritus is now in the final stage. Here, the full scope of its design, synthesis, and structure-activity relationship are described.

Full text of DOI:10.1016/j.bmc.2008.09.011

Bioorganic & Medicinal Chemistry 16 (2008) 9188–9201
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Design, synthesis, and structure–activity relationship of novel opioid j-agonists
Koji Kawai, Jun Hayakawa, Toru Miyamoto, Yoshifumi Imamura, Shinichi Yamane, Hisanori Wakita,
Hideaki Fujii , Kuniaki Kawamura, Hirotoshi Matsuura, Naoki Izumimoto, Ryosuke Kobayashi,
,
*
Takashi Endo, Hiroshi Nagase
Pharmaceutical Research Laboratories, Toray Industries, Inc., 6-10-1 Tebiro, Kamakura, Kanagawa 248-8555, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
By focusing on 4,5-epoxymorphinan, a traditional opioid skeleton but a new structure in the opioid
agonist research field, and by rationally applying the ‘message-address concept’ and ‘accessory site
j-
Received 6 August 2008
Revised 2 September 2008
Accepted 5 September 2008
Available online 9 September 2008
hypothesis,’ we discovered a new chemical class opioid -agonist, TRK-820 (1). Its development as an
j
antipruritus is now in the final stage. Here, the full scope of its design, synthesis, and structure–activity
relationship are described.
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords:
Opioid
j-Agonist
Analgesic
Antipruritus
Message-address
1. Introduction
1.1. Design rationale
For the past three decades, considerable efforts have focused on
the search for an opioid -selective agonist without the undesir-
able morphine-like side effects (e.g., respiratory depression, consti-
Portoghese et al. applied the ‘message-address concept’ for syn-
thesizing selective d- and -antagonists (Fig. 3: NTI (3) and nor-BNI
j
j
(4)).8,9 The 4,5-epoxymorphinan skeleton, found in NTI and nor-
BNI, was defined as the message subsite, and is necessary for pro-
ducing the opioid effects. The other structural site was defined as
the address site and is involved in the selectivity of the receptor
type. The receptor type selectivity of these opioid antagonists can
be regulated by alteration of the structural size of the address site
(Fig. 3). The message-address concept was applied to design a
selective opioid antagonist, and thus, to design a selective opioid
agonist with opposing effects, it was necessary to modify this
concept.
pation, physical dependence, etc.). In 1982, U-50488H was
discovered to be a highly selective
eral research groups modified its structure and succeeded in pre-
paring more selective and potent
-agonists (Fig. 1).2,3 All these
j
-agonist.1 Subsequently, sev-
j
compounds had potent antinociceptive effects in animal models
and also lacked the morphine-like side effects. However, the com-
pounds were not developed for clinical use since they, too, had side
effects, such as dysphoria and psychotomimetic effects.4 These
analogous compounds share a structure similar to the [N-C-C-
N(sp2)] pharmacophore sequence5 (shaded structures, Fig. 1) of
U-50488H. They lack the tyrosine structure which is essential for
opioid activity from the viewpoint of endogenous opioid chemistry
(Fig. 2). We questioned whether these compounds were authentic
In general, when an agonist binds a receptor, the receptor can
alter its shape to accommodate the structure of the ligand (‘in-
duced fit’). This conformational change of the receptor protein
would lead to the next signal transduction so that the agonist
exhibits its effects. As opposed to an agonist, an antagonist con-
tains a structural element that interferes with the structural
change of the receptor. Thus, even if the antagonist binds the
receptor, it does not show an effect. The structural site that medi-
ates the interference of ‘induced fit’ is called an ‘accessory site,’ and
is usually a highly hydrophobic and sterically hindered site.10 The
structural difference between an antagonist and an agonist lies
mainly in whether the compound has an accessory site or not.
j
-opioid agonists. Therefore, we designed a new type of non-pep-
tide -agonist with a novel chemical structure which incorporated
tyrosine moiety in order to distinguish the side effects of these pro-
j
totype j-agonists. Here, we report the design of a j-selective full
agonist with the 4,5-epoxymorphinan structure (Chart 1).6,7
* Corresponding author. Tel.: +81 3 5791 6372; fax: +81 3 4442 5707.
E-mail address: nagaseh@pharm.kitasato-u.ac.jp (H. Nagase).
Present address: School of Pharmacy, Kitasato University, 5-9-1 Shirokane,
Minato-ku, Tokyo 108-8641, Japan.
To design a new
j-opioid agonist based on the j-selective
antagonist nor-BNI, we proposed to remove the accessory site of
0968-0896/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2008.09.011

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9189
Cl
Cl
Cl
Cl
O
O
O
O
O
N
N
N
N
Me
N
Me
N
Me
U-50488H
U-62066
U-69593
Cl
Cl
O
O
O
O
N
N
N
S
O
N
Me
N
Me
N
Me
ICI-199441
PD-117302
CI-977
Figure 1. Structure of U-50488H and its derivatives.
Endomorphin-1 (μ) Tyr-Pro-Trp-Phe-NH2
Endomorphin-2 (μ) Tyr-Pro-Phe-Phe-NH2
[Met5]enkephalin (δ) Tyr-Gly-Gly-Phe-Met
[Leu5]enkephalin (δ) Tyr-Gly-Gly-Phe-Leu
Dynorphin A (κ) Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-Trp-Asp-Asn-Gln
Endogenous Opioids
R1
N
Tyrosine moiety
R2
HO
O
4,5-epoxymorphinan
Figure 2. Sequence of typical opioid peptides.
nor-BNI, while still maintaining the address structure. The message
site of nor-BNI, a 4,5-epoxymorphinan skeleton with a cyclopro-
pylmethyl substituent, could be indispensable for opioid activity
because it corresponds to the tyrosine residue found in endoge-
nous opioid peptides. Therefore, we speculated that the accessory
site of nor-BNI might be located within the address subsite of this
more, compound 6, which lacks the phenol ring in the address site
of nor-BNI, maintained j-receptor antagonist selectivity compara-
ble to nor-BNI.12 Thus, neither the phenol ring nor the hydroxyl
group of the ring junction in the address site of nor-BNI were re-
quired for the
j-selectivity and antagonist activity. Upon compar-
ing the -antagonist, compound 6, with naltrexone and NTI, we
j
antagonist. A key aspect of our design of a
j
-selective agonist was
proposed that the structural distance of the address site from the
to explore which part of the address subsite of nor-BNI corre-
sponded to the accessory site.
message site was an essential factor of the address subsite for
receptor selectivity (Fig. 3). Bearing this in mind, to design a
j-
The meso form analog of nor-BNI (5) has
j
-selectivity and
selective agonist, the accessory site of compound 6 must be re-
moved while still maintaining the length of the address site for
antagonist activity similar to those of nor-BNI (Fig. 4).11 Further-
Me
N
X
N
N
HO
H
O
H
O
.
O
HCl
N
SAc
HO
O
AcO
HO
OH
Me
O
KT-90 X=H, H
KT-95 X=O
Morphine
1 (TRK-820)
Chart 1. Structures of morphine, KT-90, KT-95, and compound 1 (TRK-820).

9190
K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
Based on these ideas for design, a number of compounds were
synthesized to attain the proper structural size and length on the
side chain (address subsite) for a -agonist. We found that the
side-chain structure of the 6-position had a major influence to
receptor selectivity and opioid activity (the SARs are stated below).
As a result, we identified compound 1, (2E)-N-[(5R,6R)-17-(cyclo-
propylmethyl)-4,5-epoxy-3,14-dihydroxymorphinan-6-yl]-3-(fur-
OH
OH
N
j
O
O
μ: Naltrexone (2)
OH
an-3-yl)-N-methylprop-2-enamide
hydrochloride
(TRK-820),
which was synthesized from 6b-N-methylnaltorexamine13 (b-7b)
N
N
and 3-(3-furyl)acryloyl chloride, as a potent and selective
agonist.
j-
N
O
H
δ: NTI (3)
2. Results and discussion
2.1. Chemistry
OH
OH
HO
N
For the basic design, we used naltrexone (2) as a starting mate-
rial because its 6-oxo moiety can be readily modified with various
side chains. We synthesized many derivatives to identify the most
suitable spacer X, side chain, and stereochemistry. The effects of
substitutions at the 17-nitrogen were also examined and various
N-alkyl compounds were synthesized starting from noroxycodone
(24).14
N
O
O
H
κ: nor-BNI (4)
OH HO
Message subsite
Address subsite
Scheme 1 shows the synthetic routes for the screening targets.
Thioester 14 and thioether 13c were derived from hydroxy inter-
mediates 1215 via SN2-type reactions under the appropriate reac-
tion conditions.16 Etherification and amidation transformations
were conducted under typical reaction conditions starting from
the corresponding hydroxy15 and amino13,17 intermediates (10
and 7) to give various side-chain derivatives, 11, 1, and 8a–r.
Reduction of amidomorphinan 8a with boran-dimethylsulfide
afforded amino compound 9a.
Figure 3. Message-address concept in opioid antagonist field.
the
j
-receptor interaction. Therefore, we made the address subsite
less-hindered and synthesized compound (A) to couple C6 and X
(hetero atom) with a single bond (Fig. 4). This single bond is ex-
pected to give structural flexibility to the ligand, so that the struc-
tural changes that the receptor undergoes in induced fit will occur
easily to express agonist activity.
HO
OH
O
N
OH
N
N
N
H
N
O
OH
H
N
O
H
OH
OH
4 (nor-BNI)
6 (non-Phenol Form)
OH
HO
(κ-antagonist)
N
N
minimize lipophilc part
N
O
O
H
OH
N
X
HO
OH
O
5 (meso isomer)
OH
A
Basic Design
R1
N
HO
O
R3
O
Naltrexone (2), R1 = cyclopropylmethyl, R3 = OH
Noroxycodone(24), R1 = H, R3 = OMe
Figure 4. Basic design of a new chemical class opioid j-agonist.

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9191
CPM
N
CPM
N
CPM
N
HO
O
a
HO
O
HO
O
b
O
HO
HO
HO
NHR
N
R
N
R2
R2
R
1 R = H, R2 defined in Chart 2
9a R = H, R2 = C5H11
7a R = H
7b R = Me
8a R = H, R2 = C5H11
8b R = Me, R2 = C5H11
8c-r R = Me, R2 defined in Chart 2
CPM
N
CPM
N
c, d
HO
HO
HO
O
BnO
O
O C6H13
OH
10
11
CPM
CPM
CPM
N
N
N
j, k
e, f or
g, h, i
HO
HO
O
HO
O
C5H11
SR3
YO
O
YO
HO
O
S
OH
13a Y = Me, R3 = H
12a Y = Me
12b Y = TBS
14
13b Y = TBS, R3 =C6H13
13c Y = H, R3 =C6H13
Scheme 1. Synthesis of screening targets. Reagents and conditions: (a) R2COCl, Na2CO3, THF/H2O or R2COOH, condensing agent; (b) BH3ÁSMe2, THF; (c) C6H13Br, NaH, DMF;
(d) H2, Pd/C, PhCOOH, MeOH; (e) Ph3P, iPrOCON = NCOOiPr, AcSH, THF; (f) NaOHaq, MeOH; (g) MsCl, TEA, CH2Cl2; (h) C6H13SH, LDA, THF; (i) TBAF, THF/H2O; (j) C5H11COCl,
Na2CO3, THF/H2O; (k) BBr3, CH2Cl2.
A derivative of 1 was synthesized starting from the appropri-
We examined the effects of the introduction of an unsaturated
bond and a lipophilic moiety at the side chain in the N-methyl
amide derivatives (8c–8f, Chart 2) on agonist activity and selectiv-
ity (Table 2). We also attempted to optimize the length of the side
chain. We found an attractive lead compound 8f, a 6b-cinnamam-
ately substituted 6-oxo morphinans obtained from
2 or 24
(Fig. 4).14
2.2. Pharmacology and discussion
ido derivative which showed highly selective opioid
j-agonist
We screened several compounds for the most appropriate
spacer X for opioid -agonist activity (Table 1). We fixed the side
activity in the MVD assay and pronounced in vivo agonist potency
in the AAW test, even by po-administration. Furthermore, the
duration of the agonist effect in in vivo tests was adequate. How-
ever, 8f showed a weak but significant aversive effect in the rat
conditioned place preference (CPP) test (data not shown).23
We then performed a lead optimization study by focusing on
the stereochemistry, length, and aromatic ring structure of the side
chain. Many derivatives of 8f were synthesized (Chart 2) by con-
j
chain at six carbons in length, which is similar to the size of the ad-
dress part of nor-BNI. Opioid receptor selectivity and agonistic
activity were evaluated using electrically stimulated mouse vas
deferens (MVD) or guinea pig ileum (GPI) preparations.18 The ago-
nist potencies were expressed as IC50 values, and the receptor
selectivity of each test agonist was evaluated by the Ke value. After
detecting an opioid agonist activity of the test compounds in vitro,
the acetic acid writhing (AAW) test19 using mice was conducted to
estimate in vivo potency. We also confirmed that an analgesic ef-
fect of the test compounds could be effectively antagonized by pre-
densing
a
- and b-N-methylnaltrexamine with various carboxylic
- and b-8g were
acids and were evaluated (Table 3). Compounds
a
categorized by simple combination of the morphinan structure
with U-50488H, since they have a common side chain (3,4-dichlor-
ophenylacetamido). However, their analgesic activities, especially
when administered orally, were neither potent nor long lasting.
Studies on simple derivatives of the U-50488H chemical structure
failed to identify any new drug candidates. Nonetheless, in the
course of the lead optimization process, we identified a few trends
in structure–activity relationships. (1) Compounds having the 6b-
amido structure showed lower sc/po potency ratio and long po–
duration in the AAW test. (2) The aromatic ring structure in the
C6-side chain is one of the most important components to opti-
mize the pharmacological profile, particularly with respect to
treatment with the opioid j-antagonist nor-BNI.
In the MVD assay, almost all the compounds showed similar
agonistic activity. KT-90 and KT-95,20–22 which have thioester
structures, were reported to show opioid
j-agonist activity, but
14 showed almost no agonistic activity in vitro or in vivo. This re-
sult emphasizes the importance of the chemical structure of the
‘address’ part of the agonist analog. Amide compounds, particularly
the N-methyl amido compound 8b, showed the most potent ago-
nistic activity in the AAW test and demonstrated the greatest
selectivity in the MVD assay.
j-

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K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
attenuation of psychotomimetic effects. Finally, we identified com-
pound 1 as the optimum structure, which was characterized by a
furanylacrylamide side chain.
Evaluation of the pharmacological profile of 1 revealed that the
agonist potency was 6000- and 1800-fold stronger than that of
morphine in the MVD and GPI preparations, respectively (Table
4). In comparison to U-50488H, TRK-820, 1 was 140 times and
30 times more potent on GPI and MVD, respectively. According
to the
pound 1 was 75 times more effective with
the receptors while U-50488H showed a 390-fold preference
for the receptors. Furthermore, U-50488H was the superior
selective compound as compared to 1 as long as the 1-selective
antagonist, nor-BNI,24,25 is used. However, this result suggests that
1 may have an affinity to a -receptor subtype other than that tar-
l/j
ratios of the observed Ke values in the GPI assay, com-
j
receptors than with
l
j
j-
j
j
geted by U-50488H. Compound 1 was also evaluated for its antin-
ociceptive effects in the AAW and tail flick (TF) methods in mice,
and showed high activity in both tests (Table 4). The ED50 values
of 1, indicated that this compound was 85–175 times more potent
as an analgesic than morphine and 80–350 times more potent than
U-50488H. This analgesic effect was antagonized only by the
j-
receptor antagonist, nor-BNI, but not by NTI or by low-dose nalox-
one.7 Furthermore, 1 was characterized by its low psychotomi-
metic effect. Morphine showed a significant preferential effect
and the test animals appeared to show aversion on U-50488H
administration.26,27 In this study, we thus concluded that 1 was
neutral and was expected to show less psychotomimetic side
effects.28,29
After the identification of 1 as the optimum candidate, we
tried to clarify which part of its structure was responsible for
its excellent pharmacological profile. The AAW test (sc) in mice
was selected to evaluate structure–activity and structure–
absorption, –distribution, –metabolism, and –excretion relation-
ships as a whole. Table 5 summarizes the results of a SAR study
on the AAW test (sc) of compound
1 derivatives 15–23.
Although, the main factors determining the activity in the
AAW test remain to be clarified, our data imply the importance
of each feature of the chemical structure of 1. The tyrosine com-
ponents (17-nitrogen and the 3-hydroxy group) are indispens-
able for the in vivo activity of 1 and the 17-cyclopropylmethyl,
14-hydroxy, and N-methyl substituents also contribute to its
agonist activity.
Compound 1 was originally investigated for use as an analgesic
to be delivered by iv and im injections for the control of moderate
to severe surgical pain. It was concluded that the drug was effec-
tive but its safety margin was not as sufficient as was expected
from results of animals to conduct further clinical development
on this type of pain. Additional nonclinical pharmacological studies
demonstrated that Compound 1 at very low doses inhibited itching
induced by morphine and Substance P injection.30–33 Pruritus is a
common affliction found in patients maintained on regular hemod-
ialysis, and full development of Compound 1 for uremic pruritus
was initiated after confirming its efficacy in the Phase IIa clinical
study. Presently, 1 is under application for approval as an antiprur-
itus in Japan.
3. Conclusion
We obtained a morphinan derivative, which is a new chemical
class of opioid
j
-agonist without the [N-C-C-N(sp2)] pharmaco-
phore sequence of the U-50488H derivative. We verified that the
‘message-address concept’ and the ‘accessory site hypothesis’ were
applicable in the development of this opioid
showed a significant opioid -agonist activity and induced neither
aversion nor preference in the CPP test. Presently, 1 is under appli-
j-agonist. TRK-820 (1)
j

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9193
R2
R2
Me
F
8c
8l
8m
8n
8o
8p
8q
8r
N
HO
O
8d
8e
8f
O
R2
N
6
HO
NO2
Me
Cl
Cl
8g
8h
8i
S
S
F3C
CF3
O
O
8j
1
CF3
OMe
8k
Chart 2. Structure of morphinan-6-amido derivatives.
Table 2
SAR on the variation of the side-chain R2
MVDa
AAW, ED50 (mg/kg)
po
b
Compound
IC50(nM)
Kec (nM)
sc
po/sc
Durationg
ld
de
jf
8b
8c
8d
8e
8f
15(11–19)
UDh
1797
5713
UDh
922
89.6i
UDh
143
188
263
0.046j
0.072
1.08
0.008
0.861
0.77(0.06–0.10)
0.63(0.42–0.95)
0.21 (0.16–0.29)
0.071(0.0–4–0.11)
0.29 (0.24–0.35)
0.011(0.008–0.051)
8.2
8.8
17.0
7.3
5.5
NDk
0.647(0.492–0.851)
0.457(0.322–0.647)
0.019(0.0015–0.23)
0.166(0.124–0.222)
0.024(0.018–0.031)
0.004(0.003–0.007)
0.040(0.025–0.063)
0.002(0.001–0.003)
S
L
S
L
a
b
c
d
e
f
n = 4–9 (95% confidence limits).
n = 10 (95% confidence limits).
Ke values were calculated as described in Table 1.
Naloxone (30 nM) was used as a -selective antagonist.
NTI (10 nM) was used as a d-selective antagonist.
nor-BNI (10 nM) was used as a -selective antagonist.
Dose that can inhibit 90% AAW behavior at 30 min after test compound administration (sc). AAW test was performed at each point of 60, 120, 180, and 240 min post-
l
j
g
administration. S (short): effect decreased within 120 min; L (long): effect continued until 180 min or more.
h
Undetectable.
NTI (100 nM) was used.
nor-BNI (20 nM) was used.
Not determined.
i
j
k
cation for approval as an antipruritus in Japan. At present, through-
out the world, no other agonist remains in clinical trial or in the
approval stage except TRK-820. We also obtained SAR information
which pointed out the importance of the 17-cyclopropylmethyl
and 14-hydroxy moieties, and the N-methylamido side-chain
4. Experimental
4.1. Materials
j
Synthetic reagents were purchased from Aldrich (Milwaukee,
WI, USA), Kanto Kagaku Co. (Tokyo, Japan), TCI (Tokyo, Japan), or
structure of 1 for its opioid j-agonist activity.

9194
K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
Table 3
SAR on the Variation of the Side-Chain Configuration and R2
a
b
Compound
6-a
or 6-b
MVD
AAW, ED50 (mg/kg)
Durationg
IC50 (nM)
Kec (nM)
sc
po
po/sc
ld
de
jf
8f
b
a
b
a
b
b
b
b
b
b
b
b
b
b
b
a
b
0.166 (0.124–0.222)
0.12 (0.09–0.17)
17.0 (12.9–22.4)
0.40 (0.29–0.54)
NDh
0.47 (0.26–0.84)
0.07 (0.03–0.18)
0.75 (0.44–1.27)
0.32 (0.14–0.72)
1.60 (0.81–3.18)
0.23 (0.17–0.30)
NDh
0.10 (0.07–0.13)
0.10 (0.07–0.15)
0.55 (0.40–0.74)
0.049 (0.038–0.062)
0.42 (0.28–0.64)
922
16.5
17000
263
0.43
1113
17.1
—
0.861
4.90
1.37
0.55
—
3.20
0.20
1.60
1.95
2.37
1.40
NDh
0.28
1.71
0.20
0.91
0.16
0.002 (0.001–0.003)
0.0058 (0.0044–0.0075)
0.46 (0.37–0.56)
0.017 (0.013–0.022)
0.18 (0.14–0.23)
0.0046 (0.0034–0.0062)
0.023 (0.014–0.037)
0.0011 (0.0008–0.0014)
0.0049 (0.0031–0.0077)
0.0019 (0.0012–0.0031)
0.017 (0.010–0.028)
3.6
0.0027 (0.0024–0.0031)
0.0042 (0.0011–0.0029)
0.0016 (0.0011–0.0024)
0.0081 (0.0054–0.012)
0.0033 (0.0025–0.0043)
0.011 (0.008–0.051)
5.5
39.3
39.1
48.0
—
7.4
1.1
4.4
9.7
3.7
12.9
—
9.6
9.5
9.4
16.0
9.7
L
L
0.23 (0.16–0.33)
17.99 (13.69–23.63)
0.83 (0.57–1.20)
NDh
0.034 (0.027–0.044)
0.026 (0.018–0.038)
0.0048 (0.0036–0.0070)
0.064 (0.034–0.120)
0.0070 (0.0012–0.010)
0.220 (0.150–0.300)
NDh
0.026 (0.021–0.032)
0.040 (0.008–0.015)
0.015 (0.012–0.019)
0.13 (0.10–0.18)
0.032 (0.025–0.041)
8g
NDh
S
53.0
—
8h
8i
8j
NDh
NDh
L
UDi
291
78.0
96.4
64.5
276
89.0
NDh
89.6
UDi
524
60.9
1778
UDi
8k
81
8m
8n
8o
8p
8q
8r
1
L
L
L
185
NDh
UDi
NDh
NDh
L
UDi
L
L
UDi
UDi
245
41.6
31.9
14,000
NDh
L
a
n = 4–9 (95% confidence limits).
b
c
d
e
f
n = 10 (95% confidence limits).
Ke values were calculated as described in Table 1.
Naloxone (30 nM) was used as a
NTI (10 nM) was used as a d-selective antagonist.
nor-BNI (10 nM) was used as a -selective antagonist.
Dose that can inhibit 90% AAW behavior at 30 min after test compound administration (sc). AAW test was performed at each point of 60, 120, 180, and 240 min post-
l-selective antagonist.
j
g
administration. S (short): effect decreased within 120 min; L (long): effect continued until 180 min or more.
h
Not determined.
Undetectable.
i
Sigma Chemical Co. (St. Louis, MO, USA). All reagents and solvents
used were of analytical grade from a standard commercial source
or were purified by standard methods before use.
for 30 min at the same temperature. Water and CHCl3 were added
to the reaction mixture for separation, and the aqueous layer was
extracted twice with CHCl3. After drying over anhydrous Na2SO4,
the combined organic layers were concentrated. The resulting res-
idue was purified by silica gel column chromatography or
recrystallization.
4.2. General
Melting points were determined on a Yanaco MP-500D melting
point apparatus and were uncorrected values. NMR data were ta-
ken on VALIAN GEMINI-300 (300 MHz) or JEOL GX-400
(400 MHz) spectrometers and reported in d (ppm) downfield from
tetramethylsilane. IR spectra were determined on a JASCO FT/IR-
5000 spectrophotometer. MS were obtained on a JEOL JES-D-300,
JEOL JMS-D-303 or VG ZAB-HF instrument by applying an EI meth-
od or a FAB ionization method. Elemental analyses were performed
using a Heraeus CHN-ORAPID for carbon, hydrogen, and nitrogen;
KYOTO ELECTRONICS AT-118 for chlorine; and YOKOGAWA IC-
7000 for fluorine, bromine, and sulfur. Elemental analyses results
were within 0.4% of the theoretical values. The progress of the
reactions and purity of the final products were determined on
Merck Silica Gel Art.5715. Column chromatography was carried
out using Merck Silica Gel (70–230 mesh).
4.3.2. General method B
Compound 7 was dissolved in a solution of water and THF (1:1,
ca. 0.2 M). To the solution, Na2CO3 (2 equiv) was added, and the
atmosphere of the reaction system was replaced with Ar. Then,
acid chloride (1.1 equiv) was dissolved in THF (ca. 1 M) and added
dropwise. After stirring for 30 min, MeOH (1/5 volume of the reac-
tion mixture) and 3 N aqueous NaOH (4 equiv) were added and
stirred for 1 h. AcOEt and saturated aqueous NaHCO3 were added
to the reaction mixture for separation, and the aqueous layer was
re-extracted with AcOEt. After washing with brine, the resulting
organic layer was dried over Na2SO4 and concentrated. The result-
ing residue was purified by silica gel column chromatography or
recrystallization.
4.4. Spectral data of amido compounds 1, 8a–8r, 15–18, 21–22
4.3. Amidation
4.4.1. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(furan-3-yl)-N-methylprop-2-
enamide (1) hydrochloride
4.3.1. General method A
Naltrexamine derivative 7 and Et3N (3 equiv) were dissolved in
CHCl3 (ca. 0.1 M). To this solution, various acid chlorides (2 equiv)
were added dropwise at 0 °C. After completion of dropwise addi-
tion, the reaction solution was stirred for 1 h at rt, followed by
the addition of saturated aqueous NaHCO3 for separation. The
aqueous layer was then extracted twice with CHCl3. After drying
over anhydrous Na2SO4, the combined organic layers were concen-
trated. The residue was dissolved in MeOH and CHCl3 (ca. 0.2 M).
To this solution, K2CO3 (5 equiv) was added at rt, and then stirred
Yield 85%. Mp 207–217 °C. 1H NMR (DMSO-d6, 500 MHz) d: 0.41
(1H, m), 0.54 (1H, m), 0.60 (1H, m), 0.68 (1H, m), 1.09 (1H, m),
1.20–1.50 (3H, m), 1.74 (1H, d, J = 13.7 Hz), 2.15 (1H, m), 2.45
(1H, m), 2.57 (1H, m), 2.90 (1H, m), 2.93 (1.8H, s), 3.07 (2H, m),
3.17 (1.2H, s), 3.32 (2H, m), 3.58 (0.6H, m), 3.88 (1H, m), 4.20
(0.4H, m), 4.88 (0.6H, d, J = 8.1 Hz), 4.94 (0.4H, d, J = 8.5 Hz), 6.35
(0.6H, d, J = 15.5 Hz), 6.50 (0.4H, s), 6.61 (0.6H, s), 6.62 (0.6H, s),
6.64 (0.4H, d, J = 8.1 Hz), 6.71 (0.6H, d, J = 8.1 Hz), 6.72 (0.4H, d,

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9195
J = 8.1 Hz), 6.86 (0.6H, d, J = 8.1 Hz), 6.90 (0.4H, d, J = 15.1 Hz), 7.00
(0.4H, s), 7.22 (0.6H, d, J = 15.5 Hz), 7.37 (0.4H, d, J = 15.1 Hz), 7.66
(0.6H, s), 7.72 (0.4H, s), 7.92 (0.6H, s), 8.03 (0.4H, s), 8.89 (1H, br s),
9.29 (0.4H, s), 9.70 (0.6H, s). IR (KBr, cmÀ1): 3382, 1647, 1506,
1155, 1124. MS (FAB) m/z (M+H)+ = 477. Anal. Calcd for
C28H32N2O5ÁHClÁ0.43H2O: C, 64.58; H, 6.55; N, 5.38; Cl, 6.81.
Found: C, 64.64; H, 6.76; N, 5.55; Cl, 6.85.
4.4.2. (2E)-N-[(5R,6S)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(furan-3-yl)-N-methylprop-2-
enamide (a-1) tartrate
Yield 39%. Mp 243–254 °C (dec). 1H NMR (DMSO-d6, 400 MHz)
d: 0.10–0.30 (2H, m), 0.44–0.63 (2H, m), 0.83–0.1.30 (2H, m), 1.30–
1.42 (1H, m), 1.42–1.60 (2H, m), 1.69–1.83 (1H, m), 2.12–2.41 (2H,
m), 2.41–2.65 (2H, m), 2.65–2.82 (2H, m), 2.82–2.98 (1H, m), 3.05
(3H, s), 3.05–3.16 (1H, m), 3.16–3.39 (1H, m), 2.80–3.80 (1H, br s),
4.07 (1H, s), 4.55 (0.2H, m), 4.63 (0.8H, d, J = 2.9 Hz), 4.68 (0.2H, br
s), 4.96 (0.8H, dt, J = 13.6, 4.0 Hz), 6.52 (1H, d, J = 8.3 Hz), 6.63 (1H,
d, J = 7.8 Hz), 6.72–6.87 (0.4H, m), 6.96 (0.8H, d, J = 15.1 Hz), 7.01
(0.8H, s), 7.43 (1H, d, J = 15.1 Hz), 7.72 (0.8H, s), 7.70–7.78 (1H,
m), 8.80–9.60 (1H, br s). IR (KBr, cmÀ1): 3360, 1651, 1510, 1160,
1120. MS (FAB) m/z (M+H)+ = 477. Anal. Calcd for C28H32N2O5Á0.5
(C4H6O6)Á0.8H2O: C, 63.66; H, 6.52; N, 4.95. Found: C, 63.42; H,
6.50; N, 4.87.
4.4.3. N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-hexanamide (8a) hydrochloride
Yield 37%. Mp > 210 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.40 (1H, m), 0.51 (1H, m), 0.58 (1H, m), 0.66 (1H, m), 0.86 (3H,
t, J = 6.8 Hz), 1.09 (1H, m), 1.20–1.40 (6H, m), 1.40–1.55 (4H, m),
1.65–1.75 (2H, m), 2.06 (2H, t, J = 7.1 Hz), 2.35–2.50 (2H, m), 2.85
(1H, m), 2.95–3.10 (2H, m), 3.25–3.45 (2H, m), 3.86 (1H, d,
J = 5.1 Hz), 4.55 (1H, d, J = 7.8 Hz), 6.24 (1H, s), 6.63 (1H, d,
J = 8.2 Hz), 6.72 (1H, d, J = 8.2 Hz), 8.09 (1H, d, J = 7.8 Hz), 8.87
(1H, br s), 9.37 (1H, s). IR (KBr, cmÀ1): 3245, 1652, 1504, 1128.
MS (FAB) m/z (M+H)+ = 441. Anal. Calcd for C26H36N2O4ÁHClÁ
0.7H2O: C, 63.78; H, 7.90; N, 5.72; Cl, 7.24. Found: C, 63.74; H,
7.95; N, 5.72; Cl, 7.28.
4.4.4. N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-N-methylhexanamide (8b) tartrate
Yield 43%. Mp 150–158 °C (dec). 1H NMR (DMSO-d6, 400 MHz)
d: 0.23 (2H, m), 0.48–0.59 (2H, m), 0.79 (2.1H, br t, J = 6.8 Hz),
0.88 (0.9H, br t, J = 6.8 Hz), 0.92 (1H, m), 1.11–1.22 (3H, m),
1.23–1.51 (6H, m), 1.58 (1H, m), 1.98–2.33 (5H, m), 2.52 (1H, m),
2.67–2.82 (3H, m), 2.77 (2.1H, s), 2.93 (0.9H, s). 3.11 (1H, br d,
J = 19.1 Hz), 3.33 (1H, m), 3.48 (1H, m), 3.50 (5H, br s), 4.08 (2H,
s), 4.60 (0.7H, d, J = 8.3 Hz), 4.72 (0.3H, d, J = 8.3 Hz), 6.56 (0.3H,
d, J = 7.8 Hz), 6.60 (0.7H, d, J = 7.8 Hz), 6.62 (0.3H, d, J = 7.8 Hz),
6.67 (0.7H, d, J = 7.8 Hz), 9.26 (1H, br s). IR (KBr, cmÀ1): 3314,
1719, 1618, 1460, 1120. MS (FAB) m/z (M+H)+ = 455. Anal. Calcd
for C27H38N2O4ÁC4H6O6ÁH2O: C, 59.79; H, 7.45; N, 4.50. Found: C,
59.59; H, 7.46; N, 4.67.
4.4.5. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-N-methylhex-2-enamide (8c)
tartrate
Yield 52%. Mp > 145 °C (dec). 1H NMR (DMSO-d6, 500 MHz) d:
0.25 (2H, m), 0.48–0.59 (2H, m), 0.79 (2.1H, t, J = 7.3 Hz), 0.90
(0.9H, t, J = 7.3 Hz), 0.92 (1H, m), 1.20–1.48 (5H, m), 1.58 (1H, m),
1.91–2.20 (4H, m), 2.29 (1H, m), 2.53 (1H, m), 2.67–2.85 (3H, m),
2.81 (2.1H, s), 3.01 (0.9H, s), 3.11 (1H, br d, J = 18.6 Hz), 3.31 (1H,
m), 3.45 (4.2H, br s), 3.57 (1H, m), 4.06 (1.6H, s), 4.62 (0.7H, d,
J = 7.8 Hz), 4.74 (0.3H, d, J = 7.8 Hz), 6.05 (0.7H, d, J = 15.1 Hz),
6.35–6.44 (1H, m), 6.64–6.71 (2.3H, m), 9.26 (1H, br s). IR (KBr,
cmÀ1): 3396, 1736, 1655, 1460, 1123. MS (FAB) m/z

9196
K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
Table 5
SAR on the compound 1 derivatives
R1
N
R4
O
X
R3
O
O
R1
R3
R4
X
MVDa
AAW ED50 (mg/kg, sc)
b
Compound
IC50(nM)
Kec (nM)
ld
de
jf
1
15
16
17
18
19
20
21
22
23
CPM
Me
H
Phenethyl
CPM
CPM
CPM
CPM
CPM
CPM
OH
OH
OH
OH
H
NH2
NHAc
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
H
NMe
NMe
NMe
NMe
NMe
NMe
NMe
NMe
NH
0.42 (0.28–0.64)
55 (36–84)
NDh
14,000
8.1
—
—
12.0
—
41.6
33
—
—
8.40
—
0.16
6.3
—
—
0.07
—
0.0033 (0.0025–0.0043)
1.03 (0.74–1.43)
7.07 (3.02–16.6)
1.03 (0.54–1.93)
0.013 (0.0087–0.018)
0.20 (0.13–0.30)
>10
0.02 (0.015–0.026)
0.95 (0.69–1.30)
>10
NDh
27.2 (25.0–29.4)
NDh
NDh
—
—
—
0.035 (0.029–0.041)
0.869 (0.055–1.15)
NDh
8.04
UDg
—
1.31
8100.00
—
0.07
0.44
—
OH
OH
S
a
n = 10 (95% confidence limits).
n = 4–9 (95% confidence limits).
Ke values were calculated as described in Table 1.
Naloxone (30 nM) was used as a -selective antagonist.
NTI (10 nM) was used as a d-selective antagonist.
b
c
d
e
f
l
nor-BNI (10 nM) was used as a
Undetectable.
j-selective antagonist.
g
h
Not determined.
(M+H)+ = 453. Anal. Calcd for C27H36N2O4Á0.8(C4H6O6)Á1.1H2O: C,
4.4.8. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-phenyl-N-methylprop-2-enamide
(8f) hydrochloride
61.22; H, 7.32; N, 4.73. Found: C, 61.13; H, 7.23; N, 4.82.
4.4.6. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-cyclohexyl-N-methylprop-2-
enamide (8d) tartrate
Yield 46%. Mp 225 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.42 (1H, m), 0.50 (1H, m), 0.59 (1H, m), 0.68 (1H, m), 1.07 (1H,
m), 1.20–1.50 (3.5H, m), 1.72 (1H, m), 2.13 (1H, m), 2.40–2.60
(2.5H, m), 2.87 (1H, m), 2.92 (2H, s), 3.06 (2H, m), 3.19 (1H, s),
3.32 (2H, m), 3.60–4.30 (2H, m), 4.85 (0.5H, m), 4.92 (0.5H, m),
6.30 (1H, m), 6.68 (2H, m), 6.88 (0.5H, d, J = 8.3 Hz), 7.30–7.50
(5H, m), 7.71 (0.5H, d, J = 6.4 Hz), 8.79 (1H, m), 9.29 (0.5H, s),
9.70 (0.5H, s). IR (KBr, cmÀ1): 3380, 1642, 1499, 1127. MS (FAB)
m/z (M+H)+ = 487. Anal. Calcd for C30H34N2O4ÁHClÁ0.3H2O: C,
68.18; H, 6.79; N, 5.30; Cl, 6.71. Found: C, 68.06; H, 7.11; N,
5.46; Cl, 6.37.
Yield 77%. Mp 154 °C (dec). 1H NMR (DMSO-d6, 500 MHz) d:
0.16–0.32 (2H, m), 0.42–0.62 (2H, m), 0.82–1.02 (2H, m), 1.02–
1.42 (7H, m), 1.42–1.80 (6H, m), 1.88–2.33 (4H, m), 2.42–2.58
(1H, m), 2.58–2.87 (3H, m), 2.81 (2.1H, s), 3.01 (0.9H, s), 3.09
(1H, br d, J = 18.3 Hz), 3.28 (1H, br s), 3.60 (0.7H, m), 4.05 (1H, s),
4.11 (0.3H, m), 4.61 (0.7H, d, J = 7.9 Hz), 4.73 (0.3H, d, J = 8.5 Hz),
5.93 (0.7H, d, J = 15.3 Hz), 6.33 (0.7H, d, J = 15.3 Hz), 6.34 (0.3H,
d, J = 15.3 Hz), 6.52–6.62 (1.6H, m), 6.66 (0.7H, d, J = 8.5 Hz),
8.60–9.60 (1H, br s). IR (KBr, cmÀ1): 3322, 1651, 1601, 1450,
1410, 1129. MS (FAB) m/z (M+H)+ = 493. Anal. Calcd for
C30H40N2O4Á0.7(C4H6O6)Á0.8H2O: C, 64.36; H, 7.54; N, 4.58. Found:
C, 64.37; H, 7.67; N, 4.58.
4.4.9. (2E)-N-[(5R,6S)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-phenyl-N-methylprop-2-enamide
(a-8f) tartrate
Yield 74%. Mp 254–257 °C (dec). 1H NMR (DMSO-d6, 400 MHz)
4.4.7. N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-phenyl-N-methylprop-2-anamide
(8e) hydrochloride
d: 0.21 (1H, m), 0.52 (1H, m), 0.91 (1H, m), 1.20 (1.5H, m), 1.48
(3H, m), 1.78 (1H, m), 2.26 (2.5H, m), 2.58 (1H, m), 2.73 (2H, m),
2.91 (0.5H, s), 3.06 (1H, m), 3.09 (2.5H, s), 3.20–3.90 (4H, br),
4.03 (1H, s), 4.50–5.10 (2H, m), 6.52 (1H, d, J = 7.9 Hz), 6.62 (1H,
d, J = 7.9 Hz), 7.09 (0.2H, d, J = 15.9 Hz), 7.23 (0.8H, d, J = 15.9 Hz),
7.40–7.60 (4H, m), 7.60–7.80 (2H, m), 8.80–9.20 (1H, br). IR (KBr,
cmÀ1): 3400, 1644, 1593, 1118. MS (FAB) m/z (M+H)+ = 487. Anal.
Calcd for C30H34N2O4Á0.5(C4H6O6)Á0.8H2O: C, 66.72; H, 6.75; N,
4.86. Found: C, 66.56; H, 6.74; N, 5.08.
Yield 84%. Mp 207 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.31–0.47 (1H, m), 0.47–0.55 (1H, m), 0.55–0.63 (1H, m), 0.63–
0.75 (1H, m), 0.99–1.13 (1H, m), 1.13–1.50 (3H, m), 1.60–1.78
(1H, m), 1.98–2.16 (1H, m), 2.28–2.52 (3H, m), 2.52–2.95 (2H,
m), 2.83 (2.4H, s), 2.96 (0.6H, s), 2.95–3.16 (2H, m), 3.22–3.35
(2H, m), 3.36–3.53 (1H, m), 3.83 (1H, m), 4.79 (0.8H, d,
J = 7.8 Hz), 4.85 (0.2H, d, J = 8.3 Hz), 6.38 (0.2H, m), 6.46 (0.8H,
m), 6.60–6.80 (2H, m), 7.02–7.32 (5H, m), 8.82 (1H, br s), 9.29
(0.2H, s), 9.56 (0.8H, s). IR (KBr, cmÀ1): 3416, 1622, 1502, 1125.
MS (FAB) m/z (M+H)+ = 489. Anal. Calcd for C30H36N2O4Cl2ÁHClÁ
0.2H2O: C, 67.92; H, 7.11; N, 5.28; Cl, 6.68. Found: C, 67.96; H,
7.06; N, 5.27; Cl, 6.85.
4.4.10. N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3,4-dichlorophenyl)-N-
methylacetamide (8g) hydrochloride
Yield 51%. Mp 194–196 °C (dec). 1H NMR (CDCl3+D2O, 400 MHz,
free base) d: 0.09–0.17 (2H, m), 0.49–0.57 (2H, m), 0.78–0.89 (2H,

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9197
m), 1.05 (0.7H, dt, J = 13.2, 3.4 Hz), 1.42–1.51 (0.3H, m), 1.49 (2H,
br d, J = 13.2 Hz), 1.97–2.29 (3H, m), 2.36 (2H, d, J = 6.4 Hz), 2.56–
2.69 (2H, m), 2.92 (2.1H, s), 2.99 (0.9H, s), 3.00–3.08 (2H, m),
3.48 (0.7H, d, J = 15.6 Hz), 3.49–3.56 (1H, m), 3.66 (0.7H, d,
J = 15.6 Hz), 3.70 (0.6H, s), 4.55 (0.3H, d, J = 8.3 Hz), 4.58 (0.7H, d,
J = 8.3 Hz), 6.57 (0.3H, d, J = 8.3 Hz), 6.73 (0.3H, d, J = 8.3 Hz),
6.78–6.82 (1.4H, m), 6.83 (0.7H, d, J = 8.3 Hz), 7.11 (0.3H, dd,
J = 8.3, 2.5 Hz), 7.23 (0.7H, d, J = 8.3 Hz), 7.36 (0.3H, d, J = 2.0 Hz),
7.39 (0.3H, d, J = 8.3 Hz), 7.63 (0.7H, d, J = 2.0 Hz). IR (KBr, cmÀ1):
3420, 1620, 1127. MS (FAB) m/z (M+H)+ = 543. Anal. Calcd for
C29H32N2O4Cl2ÁHClÁ0.7H2O: C, 58.78; H, 5.85; N, 4.73; Cl, 17.95.
Found: C, 58.72; H, 5.86; N, 4.71; Cl, 18.03.
J = 8.3 Hz), 4.79 (0.3H, d, J = 7.8 Hz), 6.50–6.70 (1.3H, m), 6.80–
6.90 (1.4H, m), 7.34 (1H, d, J = 15.6 Hz), 7.51 (0.3H, d, J = 15.6 Hz),
7.70–7.80 (3.7H, m), 7.94 (0.3H, d, J = 8.3 Hz). IR (KBr, cmÀ1):
3400, 1649, 1601, 1168, 1114. MS (FAB) m/z (M+H)+ = 555. Anal.
Calcd for C31H33N2O4F3Á0.5(C4H6O6)Á0.3 H2O: C, 62.41; H, 5.81; N,
4.41; F, 8.98. Found: C, 62.36; H, 5.80; N, 4.41; F, 8.98.
4.4.15. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3-methoxyphenyl)-N-
methylprop-2-enamide (8k) tartrate
Yield 88%. Mp 160 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.15–0.35 (2H, m), 0.45–0.65 (2H, m), 0.85–1.05 (1H, m), 1.20–
1.50 (3H, m), 1.52–1.70 (1H, m), 2.00–2.25 (2H, m), 2.25–2.42
(1H, m), 2.63–2.77 (3H, m), 2.90 (1.8H, s), 2.90–4.20 (3H, br s),
3.05–3.22 (1H, m), 3.15 (1.2H, s), 3.22–3.42 (1H, m), 3.50–3.74
(1.6H, m), 3.77 (1.8H, s), 3.80 (1.2H, s), 4.00 (1H, s), 4.20 (0.4H,
br s), 4.71 (0.6H, d, J = 7.8 Hz), 4.80 (0.4H, d, J = 8.3 Hz), 6.55–6.71
(2.6H, m), 6.92 (0.6H, dd, J = 8.3, 2.5 Hz), 6.95–7.03 (1H, m), 7.10
(0.6H, d, J = 7.3 Hz), 7.17 (0.4H, d, J = 15.1 Hz), 7.23–7.35 (2.4H,
m), 7.42 (0.4H, d, J = 15.6 Hz), 9.07 (0.4H, br s), 9.37 (0.6H, br s).
IR (KBr, cmÀ1): 3390, 1642, 1599, 1460, 1127. MS (FAB) m/z
(M+H)+ = 517. Anal. Calcd for C31H36N2O5Á0.5(C4H6O6)Á0.7 H2O: C,
65.59; H, 6.74; N, 4.64. Found: C, 65.46; H, 6.78; N, 4.70.
4.4.11. N-[(5R,6S)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3,4-dichlorophenyl)-N-
methylacetamide (a-8g) hydrochloride
Yield 58%. Mp 252–254 °C. 1H NMR (DMSO-d6, 400 MHz) d: 0.43
(2H, m), 0.65 (2H, m), 1.05 (1H, m), 1.16 (1.5H, m), 1.37 (1H, m),
1.58 (2H, m), 1.92 (1H, m), 2.43 (1H, m), 2.68 (1H, m), 2.81
(0.5H, s), 2.96 (2.5H, s), 3.05 (2.5H, m), 3.30 (2H, m), 3.85 (3H,
m), 4.48 (0.2H, m), 4.62 (0.8H, d, J = 3.9 Hz), 4.75 (0.2H, m), 4.96
(0.8H, m), 6.21 (0.8H, m), 6.46 (0.2H, m), 6.58 (1H, d, J = 8.3 Hz),
6.72 (1H, d, J = 8.3 Hz), 7.25 (1H, m), 7.55 (2H, m), 8.80 (1H, br s),
9.32 (1H, br s). IR (KBr, cmÀ1): 3370, 1620, 1510, 1120. MS (FAB)
m/z (M+H)+ = 543. Anal. Calcd for C29H32N2O4Cl2ÁHClÁ0.5 H2O: C,
59.14; H, 5.82; N, 4.75; Cl, 18.06. Found: C, 59.34; H, 5.78; N,
4.78; Cl, 17.78.
4.4.16. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3-methylphenyl)-N-methylprop-
2-enamide (8l) hydrochloride
Yield 87%. Mp 245 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.42 (1H, m), 0.50 (1H, m), 0.59 (1H, m), 0.69 (1H, m), 1.07 (1H,
m), 1.20–1.50 (3H, m), 1.72 (1H, d, J = 13.7 Hz), 2.12 (1H, m), 2.34
(3H, s), 2.40–2.60 (2H, m), 2.88 (1H, m), 2.92 (2H, s), 3.00–3.10
(2H, m), 3.18 (1H, s), 3.30–3.40 (2H, m), 3.66 (0.7H, m), 3.83 (1H,
m), 4.20 (0.3H, m), 4.83 (0.7H, d, J = 7.8 Hz), 4.90 (0.3H, d,
J = 8.3 Hz), 6.60–6.80 (2H, m), 6.85 (0.7H, d, J = 8.3 Hz), 7.10–7.30
(4.4H, m), 7.41 (0.3H, d, J = 15.1 Hz), 7.48 (0.3H, d, J = 7.3 Hz),
7.54 (0.3H, br s). IR (KBr, cmÀ1): 3390, 1647, 1605, 1323, 1127.
MS (FAB) m/z (M+H)+ = 501. Anal. Calcd for C31H36N2O4ÁHClÁ
0.8H2O: C, 67.51; H, 7.06; N, 5.08; Cl, 6.43. Found: C, 67.35; H,
7.05; N, 5.17; Cl 6.53.
4.4.12. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(2-trifluoromethylphenyl)-N-
methylprop-2-enamide (8h) hydrochloride
Yield 93%. Mp 196–199 °C. 1H NMR (DMSO-d6, 400 MHz) d: 0.41
(1H, m), 0.53 (1H, m), 0.59 (1H, m), 0.67 (1H, m), 1.09 (1H, m),
1.30–1.50 (3H, m), 1.73 (1H, d, J = 13.2 Hz), 2.20 (1H, m), 2.40–
2.60 (2H, m), 2.88 (1H, m), 2.97 (2H, s), 3.00–3.10 (2H, m), 3.23
(1H, s), 3.30–3.40 (2H, m), 3.68 (0.7H, m), 3.87 (1H, br s), 4.18
(0.3H, m), 4.88 (0.7H, d, J = 7.8 Hz), 4.97 (0.3H, d, J = 8.3 Hz),
6.60–6.90 (2.7H, m), 7.28 (0.3H, d, J = 15.1 Hz), 7.50–7.70 (1.7H,
m), 7.70–7.90 (3H, m), 8.14 (0.3H, d, J = 7.8 Hz). IR (KBr, cmÀ1):
3400, 1649, 1605, 1460, 1125. MS (FAB) m/z (M+H)+ = 555. Anal.
Calcd for C31H33N2O4F3Á1.1HClÁ0.4H2O: C, 61.86; H, 5.84; N, 4.65;
Cl, 6.48; F, 9.47. Found: C, 61.88; H, 5.94; N, 4.67; Cl, 6.44; F, 9.47.
4.4.17. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3-fluorophenyl)-N-methylprop-
2-enamide (8m) tartrate
4.4.13. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3-trifluoromethylphenyl)-N-
methylprop-2-enamide (8i) tartrate
Yield 81%. Mp 145–153 °C 1H NMR (DMSO-d6, 400 MHz) d:
0.20–0.32 (2H, m), 0.46–0.62 (2H, m), 0.88–1.00 (1H, m), 1.20–
1.50 (3H, m), 1.55–1.65 (1H, m), 2.00–2.40 (3H, m), 2.42–2.60
(2H, m), 2.70–2.88 (3H, m), 2.90 (2.1H, s), 3.05–4.00 (7H, m),
3.15 (0.9H, s), 4.11 (2H, s), 4.71 (0.7H, d, J = 8.1 Hz), 4.81 (0.3H, d,
J = 8.1 Hz), 6.58–6.68 (3H, m), 7.14–7.68 (5H, m), 9.15 (0.3H, br
s), 9.45 (0.7H, br s). IR (KBr, cmÀ1): 3320, 1731, 1647, 1127. MS
(FAB) m/z (M+H)+ = 505. Anal. Calcd for C30H33N2O4 FÁC4H6O6ÁH2O:
C, 60.71; H, 6.14; N, 4.16; F, 2.82. Found: C, 60.63; H, 6.22; N, 4.07;
F, 2.81.
Yield 84%. Mp 156–159 °C. 1H NMR (DMSO-d6, 400 MHz) d: 0.21
(2H, m), 0.52 (2H, m), 0.91 (1H, m), 1.20–1.50 (3H, m), 1.57 (1H, d,
J = 13.2 Hz), 2.12 (2H, m), 2.29 (1H, m), 2.49 (1H, m), 2.60–2.80
(3H, m), 2.90 (2H, s), 3.08 (1H, d, J = 18.6 Hz), 3.17 (1H, s), 3.26
(1H, m), 3.67 (0.7H, m), 4.02 (1H, s), 4.21 (0.3H, m), 4.68 (0.7H, d,
J = 7.8 Hz), 4.79 (0.3H, d, J = 8.3 Hz), 6.60–6.80 (2.6H, m), 7.37
(1H, dd, J = 7.3, 16.1 Hz), 7.50–7.80 (3.8H, m), 8.02 (0.3H, d,
J = 7.8 Hz), 8.14 (0.3H, s). IR (KBr, cmÀ1): 3350, 1649, 1601, 1168,
1127. MS (FAB) m/z (M+H)+ = 555. Anal. Calcd for
C31H33N2O4F3Á0.5(C4H6O6)Á0.3 H2O: C, 62.41; H, 5.81; N, 4.41; F,
8.98. Found: C, 62.32; H, 5.99; N, 4.48; F, 8.88.
4.4.18. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(3-nitrophenyl)-N-methylprop-2-
enamide (8n) hydrochloride
Yield 47%. Mp 161–164 °C. 1H NMR (DMSO-d6, 400 MHz) d:
0.18–0.30 (2H, m), 0.46–0.60 (2H, m), 0.85–0.97 (1H, m), 1.22–
1.50 (3H, m), 1.53–1.62 (1H, m), 2.03–2.21 (2H, m), 2.23–2.35
(1H, m), 2.50–2.90 (4H, m), 2.91 (2.1H, s), 3.18 (0.9H, s), 3.10–
4.20 (3H, m), 4.05 (1H, s), 4.67 (0.7H, d, J = 8.3 Hz), 4.81 (0.3H, d,
J = 8.3 Hz), 6.58 (0.3H, d, J = 7.8 Hz), 6.84 (0.7H, d, J = 15.6 Hz),
7.42 (0.3H, d, J = 15.9 Hz), 7.45 (0.7H, d, J = 15.6 Hz), 7.57 (0.3H,
d, J = 15.6 Hz), 7.66 (0.7H, dd, J = 8.3, 7.8 Hz), 7.71 (0.3H, dd,
4.4.14. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(4-trifluoromethylphenyl)-N-
methylprop-2-enamide (8j) tartrate
Yield 84%. Mp 167–170 °C. 1H NMR (DMSO-d6, 400 MHz) d: 0.21
(2H, m), 0.52 (2H, m), 0.91 (1H, m), 1.20–1.40 (3H, m), 1.58 (1H,
m), 2.10–2.20 (2H, m), 2.30 (1H, m), 2.49 (1H, m), 2.60–2.80 (3H,
m), 2.90 (2H, s), 3.16 (1H, s), 3.18 (1H, d, J = 18.6 Hz), 3.24 (1H,
m), 3.65 (0.7H, m), 4.03 (1H, s), 4.20 (0.3H, m), 4.68 (0.7H, d,

9198
K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
J = 8.3, 7.8 Hz), 7.93 (0.7H, d, J = 7.8 Hz), 8.15–8.27 (2H, m), 8.60
(0.3H, s), 9.12 (0.3H, br s), 9.28 (0.7H, br s). IR (KBr, cmÀ1): 3380,
1649, 1601, 1531, 1127. MS (FAB) m/z (M+H)+ = 532. Anal. Calcd
for C30H33N3O6Á0.5(C4H6O6)Á2.2H2O: C, 59.47; H, 6.30; N, 6.50.
Found: C, 59.42; H, 5.96; N, 6.25.
7.14 (0.5H, d, J = 15.1 Hz), 7.28 (0.5H, d, J = 15.6 Hz), 7.68 (0.5H,
s), 7.80 (0.5H, s). IR (KBr, cmÀ1): 3390, 1647, 1597, 1127. MS
(FAB) m/z (M+H)+ = 477. Anal. Calcd for C28H32N2O5ÁHClÁ0.6 H2O:
C, 64.20; H, 6.58; N, 5.35; Cl, 6.77. Found: C, 64.21; H, 6.84; N,
5.38; Cl, 6.69.
4.4.23. (2E)-N-[(5R,6R)-4,5-Epoxy-3,14-dihydroxy-17-
methylmorphinan-6-yl]-3-(furan-3-yl)-N-methylprop-2-
enamide (15) hydrochloride
4.4.19. N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-N-methyl-1-naphthamide (8o)
hydrochloride
Mp > 250 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d: 1.20–1.45
(3H, m), 1.66 (1H, d, J = 14.2 Hz), 2.12 (1H, m), 2.80–2.85 (3H, m),
2.90–3.15 (4.6H, m), 3.30–3.35 (2H, m), 3.35 (1.2H, s), 3.57 (1.8H,
br s), 4.20 (0.4H, br s), 4.86 (0.6H, d, J = 8.0 Hz), 4.91 (0.4H, d,
J = 8.3 Hz), 6.34 (0.6H, d, J = 15.6 Hz), 6.40 (0.4H, s), 6.51 (0.6H, s),
6.60–6.75 (2H, m), 6.84 (0.6H, d, J = 8.1 Hz), 6.90 (0.4H, d, J =
15.1 Hz), 7.00 (0.4H, s), 7.21 (0.6H, d, J = 15.6 Hz), 7.36 (0.4H, d,
J = 15.1 Hz), 7.66 (0.6H, s), 7.73 (0.4H, s), 7.92 (0.6H, s), 8.04
(0.4H, s), 9.19 (1H, br s), 9.31 (0.4H, s), 9.72 (0.6H, s). IR (KBr,
cmÀ1): 3376, 1647, 1503, 1157, 1122. MS (FAB) m/z
(M+H)+ = 437. Anal. Calcd for C25H28N2O5ÁHClÁ0.6H2OÁ0.14AcOEt:
C, 61.88; H, 6.36; N, 5.65; Cl, 7.15. Found: C, 61.97; H, 6.48; N,
5.43; Cl, 7.22.
Yield 95%. Mp 220 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.34 (1H, m), 0.47 (1H, m), 0.54 (1H, m), 0.62 (1H, m), 0.87 (1H,
m), 0.99 (1H, m), 1.28 (1H, m), 1.40–1.60 (2H, m), 2.17 (1H, m),
2.34 (1H, m), 2.52 (1H, m), 2.70–2.90 (2H, m), 3.01 (1H, m), 3.10
(2H, s), 3.20–3.40 (3.7H, m), 3.70 (0.7H, m), 3.87 (0.3H, m), 4.15
(0.3H, m), 5.00 (0.7H, d, J = 7.8 Hz), 5.06 (0.3H, m), 6.37 (0.3H, m),
6.39 (0.7H, d, J = 7.8 Hz), 6.58 (0.7H, d, J = 8.3 Hz), 6.71 (0.3H,
m), 7.60–8.00 (7H, m). IR (KBr, cmÀ1): 3400, 1620, 1319,
1176, 1120. MS (FAB) m/z (M+H)+ = 511. Anal. Calcd for
C32H34N2O4ÁHClÁ0.4H2O: C, 69.34; H, 6.51; N, 5.05; Cl, 6.40. Found:
C, 69.13; H, 6.86; N, 4.96; Cl, 6.73.
4.4.20. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(thiophen-2-yl)-N-methylprop-2-
enamide (8p) tartrate
4.4.24. (2E)-N-[(5R,6R)-4,5-Epoxy-3,14-dihydroxymorphinan-6-
yl]-3-(furan-3-yl)-N-methylprop-2-enamide (16) tartrate
Yield 78%. Mp > 160 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
1.36 (2H, m), 1.62 (1H, m), 2.07 (1H, m), 2.44 (2H, m), 2.89 (2H,
s), 2.98 (1H, m), 3.11 (2H, m), 3.53 (1.5H, m), 3.90 (6H, br s), 3.85
(2H, s), 4.18 (0.5H, m), 4.71 (0.5H, d, J = 7.8 Hz), 4.80 (0.5H, d,
J = 8.3 Hz), 6.36 (0.5H, d, J = 15.6 Hz), 6.62 (1H, br s), 6.65 (0.5H,
d, J = 7.8 Hz), 6.69 (0.5H, d, J = 7.8 Hz), 6.81 (0.5H, d, J = 7.8 Hz),
6.89 (0.5H, d, J = 15.6 Hz), 6.99 (0.5H, br s), 7.21 (0.5H, d,
J = 15.6 Hz), 7.36 (0.5H, d, J = 15.6 Hz), 7.66 (0.5H, br s), 7.72
(0.5H, br s), 7.91 (0.5H, s), 8.03 (0.5H, s), 9.67 (1H, br s). IR (KBr,
cmÀ1): 3858, 1651, 1595, 1410, 1135. MS (FAB) m/z (M+H)+ =
423. Anal. Calcd for C24H26N2O5ÁC4H6O6: C, 58.74; H, 5.63; N,
4.89. Found: C, 58.66; H, 5.76; N, 4.93.
Yield 84%. Mp 178–171 °C. 1H NMR (DMSO-d6, 400 MHz) d: 0.22
(2H, m), 0.53 (2H, m), 0.91 (1H, m), 1.20–1.40 (3H, m), 1.58 (1H, d,
J = 10.4 Hz), 2.14 (2H, m), 2.27 (1H, m), 2.50 (1H, m), 2.60–2.80 (3H,
m), 2.88 (1.8H, s), 3.08 (1H, d, J = 17.1 Hz), 3.11 (1.2H, s), 3.24 (1H,
m), 3.59 (0.6H, m), 4.02 (1H, s), 4.20 (0.4H, m), 4.66 (0.6H, d,
J = 8.6 Hz), 4.76 (0.4H, d, J = 8.6 Hz), 6.42 (0.6H, d, J = 7.9 Hz), 6.48
(0.4H, d, J = 12.2 Hz), 6.57 (1H, d, J = 7.9 Hz), 6.75 (0.6H, d,
J = 7.9 Hz), 6.85 (0.4H, d, J = 15.3 Hz), 7.07 (0.6H, t, J = 3.7 Hz),
7.12 (0.4H, t, J = 4.9 Hz), 7.32 (0.6H, d, J = 3.1 Hz), 7.45–7.48 (1H,
m), 7.58–7.67 (1.4H, m). IR (KBr, cmÀ1): 3350, 1636, 1590, 1460,
1035. MS (FAB) m/z (M+H)+ = 493. Anal. Calcd for
C28H32N2O4SÁ0.5(C4H6O6)Á0.5 H2O: C, 62.48; H, 6.29; N, 4.86; S,
5.56. Found: C, 62.32; H, 6.36; N, 4.92; S, 5.57.
4.4.25. (2E)-N-[(5R,6R)-4,5-Epoxy-3,14-dihydroxy-17-
phenethylmorphinan-6-yl]-3-(furan-3-yl)-N-methylprop-2-
enamide (17) hydrochloride
4.4.21. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(thiophen-3-yl)-N-methylprop-2-
enamide (8q) methansulfonate
Mp 225 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d: 1.28 (0.4H,
m), 1.30–1.50 (2.6H, m), 1.75 (1H, d, J = 13.4 Hz), 2.16 (1H, m),
2.50–2.60 (2H, m), 2.85–2.95 (3H, m), 3.00–3.25 (6H, m), 3.35–
3.50 (1.6H, m), 3.80 (1H, m), 4.21 (0.4H, m), 4.88 (0.6H, d,
J = 8.1 Hz), 4.93 (0.4H, d, J = 8.3 Hz), 6.36 (0.6H, d, J = 15.6 Hz),
6.46 (0.4H, br s), 6.57 (0.6H, br s), 6.60–6.75 (2H, m), 6.86 (0.6H,
d, J = 8.1 Hz), 6.91 (0.4H, d, J = 15.1 Hz), 7.01 (0.4H, s), 7.23 (0.6H,
d, J = 15.4 Hz), 7.25–7.50 (5.4H, m), 7.67 (0.6H, s), 7.73 (0.4H, s),
7.92 (0.6H, s), 8.03 (0.4H, s), 9.18 (1H, br s), 9.31 (0.4H, s), 9.70
(0.6H, s). IR (KBr, cmÀ1): 3377, 1647, 1503, 1158, 1126. MS
(FAB) m/z (M+H)+ = 527. Anal. Calcd for C32H34N2O5ÁHClÁ0.4H2OÁ
0.1AcOEt: C, 67.20; H, 6.37; N, 4.84; Cl, 6.12. Found: C, 67.10; H,
6.41; N, 4.83; Cl, 6.01.
Yield 88%. Mp 235 °C. 1H NMR (DMSO-d6, 400 MHz) d: 0.42 (1H,
m), 0.51 (1H, m), 0.60 (1H, m), 0.68 (1H, m), 1.08 (1H, m), 1.20–
1.50 (3H, m), 1.72 (1H, d, J = 12.2 Hz), 2.12 (1H, m), 2.34 (3H, s),
2.40–2.50 (2H, m), 2.86 (1H, m), 2.91 (2H, s), 3.00–3.10 (2H, m),
3.15 (1H, s), 3.30–3.50 (2H, m), 3.61 (0.7H, m), 3.82 (1H, br s),
4.19 (0.3H, m), 4.81 (0.7H, d, J = 7.8 Hz), 4.89 (0.3H, d, J = 8.3 Hz),
6.46 (0.7H, d, J = 15.6 Hz), 6.60–6.70 (1.3H, m), 6.85 (0.7H, d,
J = 7.8 Hz), 7.00 (0.3H, d, J = 15.1 Hz), 7.26 (0.7H, d, J = 4.9 Hz),
7.31 (0.7H, d, J = 15.6 Hz), 7.46 (0.3H, d, J = 15.1 Hz), 7.50–7.70
(2H, m), 7.87 (0.3H, s). IR (KBr, cmÀ1): 3410, 1642, 1595, 1323,
1127. MS (FAB) m/z (M+H)+ = 493. Anal. Calcd for
C28H32N2O4SÁCH3SO3 HÁ0.2 H2O: C, 58.80; H, 6.19; N, 4.73; S,
10.83. Found: C, 58.60; H, 6.42; N, 4.72; S, 10.82.
4.4.26. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-14-
hydroxymorphinan-6-yl]-3-(furan-3-yl)-N-methylprop-2-
enamide (18) hydrochloride
4.4.22. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(furan-2-yl)-N-methylprop-2-
enamide (8r) hydrochloride
Yield 44%. Mp 190–195 °C (dec). 1H NMR (DMSO-d6, 400 MHz)
d: 0.44 (1H, m), 0.53 (1H, m), 0.60 (1H, m), 0.69 (1H, m), 1.09
(1H, m), 1.25 (0.5H, m), 1.35–1.45 (2H, m), 1.51 (0.5H, m), 1.75
(1H, m), 2.14 (1H, m), 2.35–2.60 (2H, m), 2.88 (1H, m), 2.93
(1.5H, s), 3.05 (1H, m), 3.16 (1.5H, s), 3.18 (1H, m), 3.43 (0.5H, d,
J = 7.3 Hz), 3.48 (0.5H, d, J = 8.3 Hz), 3.63 (0.5H, m), 3.92 (1H, m),
4.24 (0.5H, m), 4.84 (0.5H, d, J = 8.3 Hz), 4.91 (0.5H, d, J = 8.3 Hz),
6.35 (0.5H, d, J = 15.6 Hz), 6.50 (0.5H, s), 6.66 (0.5H, d, J = 7.8 Hz),
Yield 80%. Mp 200 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d:
0.42 (1H, m), 0.53 (1H, m), 0.61 (1H, m), 0.69 (1H, m), 1.08 (1H,
m), 1.28 (0.5H, m), 1.30–1.50 (2.5H, m), 1.74 (1H, m), 2.15 (1H,
m), 2.40–2.60 (2.5H, m), 2.80–2.90 (1.5H, m), 2.93 (1.5H, s),
3.00–3.10 (2H, m), 3.16 (1.5H, s), 3.30–3.40 (2H, m), 3.61 (0.5H,
m), 3.85 (1H, br s), 4.20 (0.5H, m), 4.85 (0.5H, d, J = 7.3 Hz), 4.91
(0.5H, d, J = 7.8 Hz), 6.40–6.70 (3.5H, m), 6.80–6.90 (1.5H, m),

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9199
6.70 (0.5H, d, J = 7.8 Hz), 6.84 (0.5H, d, J = 7.8 Hz), 6.85–7.00 (1.5H,
4.6. Synthesis of (5R,6R)-17-(cyclopropylmethyl)-4,5-epoxy-6-
m), 7.18 (0.5H, t, J = 7.8 Hz), 7.21 (0.5H, t, J = 7.8 Hz), 7.30 (0.5H, d,
J = 15.1 Hz), 7.36 (0.5H, d, J = 15.1 Hz), 7.70 (0.5H, s), 7.72 (0.5H, s),
7.96 (0.5H, s), 8.03 (0.5H, s). IR (KBr, cmÀ1): 3300, 1650, 1504,
1122, 1023. MS (FAB) m/z (M+H)+ = 461. Anal. Calcd for
C28H32N2O4ÁHClÁ0.3H2O: C, 66.93; H, 6.74; N, 5.57; Cl, 7.06. Found:
C, 66.86; H, 6.81; N, 5.66; Cl, 6.96.
hexyloxy-3,14-dihydroxymorphinan (11) hydrochloride
NaH (60% mineral oil, 115.4 mg, 2.89 mmol) was washed with
dried pentane. After the solid was suspended with DMF (10 mL),
3-O-benzyl-6b-naltrexol (10, 308 mg, 0.69 mmol) was added. To
the reaction mixture, n-hexyl bromide (0.12 mL, 0.94 mmol) was
added, and the resulting mixture was stirred for 24 h at 70 °C. After
removing the solvent, saturated aqueous NH4Cl, saturated ammo-
nia, and AcOEt were added for separation. The organic layer was
washed with water and brine, and then dried over Na2SO4. The
crude material obtained by concentration was purified by silica
gel column chromatography (c-hexane:AcOEt = 2/1) to give a ben-
zyl ether compound as an oil (254.2 mg, 71%).
The benzyl ether moiety of the compound (254.2 mg,
0.49 mmol) was deprotected by 10% Pd/C (250 mg) catalyzed
hydrogenolysis with PhCO2H (84.0 mg, 0.69 mmol) in MeOH
(10 mL). After removing the catalyst, saturated aqueous NaHCO3
and AcOEt were added for separation. The organic layer was
washed with brine and then concentrated to give a crude product.
The crude material was purified by silica gel column chromatogra-
phy (c-hexane/AcOEt/NH4OH = 275:25:2 ꢀ 200:100:2) and dis-
solved in AcOEt, and then HCl/MeOH was added to the resulting
mixture. The precipitated hydrochloric acid salt was collected by
filtration to give the captioned compound as white powder
(184.3 mg, 81%). Mp 240–245 °C (dec). 1H NMR (DMSO-d6,
400 MHz) d: 0.40 (1H, m), 0.51 (1H, m), 0.59 (1H, m), 0.67 (1H,
m), 0.87 (3H, t, J = 6.8 Hz), 1.07 (1H, m), 1.20–1.35 (7H, m), 1.39
(1H, d, J = 8.8 Hz), 1.40–1.50 (2H, m), 1.65–1.75 (3H, m), 2.35–
2.45 (2H, m), 2.85 (1H, m), 2.95–3.05 (3H, m), 3.25–3.35 (2H, m),
3.47 (2H, dd, J = 6.3, 2.2 Hz), 3.87 (1H, d, J = 5.4 Hz), 4.44 (1H, d,
J = 6.4 Hz), 6.30 (1H, s), 6.60 (1H, d, J = 8.3 Hz), 6.72 (1H, d,
J = 8.3 Hz), 8.84 (1H, br s), 9.41 (1H, s). IR (KBr, cmÀ1): 3233,
1636, 1505, 1116, 1035. MS (FAB) m/z (M+H)+ = 428. Anal. Calcd
for C26H37NO4ÁHClÁ0.15H2O: C, 66.91; H, 8.27; N, 3.00; Cl, 7.60.
Found: C, 66.84; H, 8.25; N, 3.05; Cl, 7.53.
4.4.27. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3-
hydroxymorphinan-6-yl]-3-(furan-3-yl)-N-methylprop-2-
enamide (21) hydrochloride
Mp 225–230 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d: 0.38
(1H, m), 0.51 (1H, m), 0.63 (2H, m), 0.97 (1H, m), 1.21 (1H, m),
1.40–1.72 (3.8H, m), 2.29 (1H, m), 2.40–2.52 (1.2H, m), 2.57
(0.2H, m), 2.70 (0.8H, m), 2.80–2.96 (1.2H, m), 2.89 (2.4H, s),
3.00–3.18 (1.6H, m), 3.14 (0.6H, s), 3.18–3.35 (2.2H, m), 3.48
(0.8H, m), 3.95–4.10 (1.2H, m), 4.65–4.95 (1H, m), 6.27–8.32 (7H,
m). IR (KBr, cmÀ1): 3370, 1651, 1593, 1156. MS (FAB) m/z
(M+H)+ = 461. Anal. Calcd for C28H32N2O4Á1.7HClÁ0.5H2O: C,
63.27; H, 6.58; N, 5.27; Cl, 11.34. Found: C, 63.24; H, 6.60; N,
5.09; Cl, 11.55.
4.4.28. (2E)-N-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(furan-3-yl)prop-2-enamide (22)
hydrochloride
Mp 240 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d: 0.41 (1H, m),
0.52 (1H, m), 0.59 (1H, m), 0.67 (1H, m), 1.07 (1H, m), 1.32–1.49
(2H, m), 1.57 (1H, m), 1.68–1.83 (2H, m), 2.37–2.47 (2H, m), 2.86
(1H, m), 2.98–3.12 (2H, m), 3.27–3.39 (2H, m), 3.52 (1H, m), 3.86
(1H, br d, J = 4.9 Hz), 4.60 (1H, d, J = 7.8 Hz), 6.23 (1H, br s), 6.33
(1H, d, J = 15.6 Hz), 6.65 (1H, d, J = 7.8 Hz), 6.72 (1H, d, J = 7.8 Hz),
6.73 (1H, br s), 7.32 (1H, d, J = 15.6 Hz), 7.74 (1H, br s), 8.01 (1H,
s), 8.40 (1H, d, J = 7.8 Hz), 8.86 (1H, m), 9.36 (1H, s). IR (KBr,
cmÀ1): 3376, 1663, 1508, 1460, 1156, 1127. MS (FAB) m/z
(M+H)+ = 463. Anal. Calcd for C27H30N2O5ÁHClÁ0.2H2O: C, 64.52;
H, 6.30; N, 5.57; Cl, 7.05. Found: C, 64.50; H, 6.39; N, 5.53; Cl, 7.00.
4.5. Synthesis of N-hexyl-[(5R,6R)-17-(cyclopropylmethyl)-4,5-
4.7. Synthesis of (5R,6R)-17-(cyclopropylmethyl)-4,5-epoxy-6-
epoxy-3,14-dihydroxymorphinan]-6-amine (9a) hydrochloride
hexylthio-3,14-dihydroxymorphinan (13c) hydrochloride
Amidomorphinan 8a (290 mg, 0.66 mmol) dissolved in dried
THF (3 mL) was added to the THF solution of BH3ÁMe2S (2.0 M,
1.0 mL, 2.0 mmol). The resulting mixture was heated for refluxing
and stirred for 1 h. BH3ÁMe2S (2.0 M, 0.25 mL, 0.5 mmol) was added
and refluxing was continued for an additional 2 h. To the reaction
mixture, 6 N HCl (1.2 mL), water (2.0 mL), and MeOH (3.0 mL) were
added and stirred for 1 h under a reflux condition. The reaction
mixture was cooled to rt and was separated with AcOEt and satu-
rated aqueous ammonia. The organic layer was washed with brine,
dried over Na2SO4, and concentrated to give a crude product. The
resulting crude product was purified by silica gel column chroma-
tography (AcOEt ꢀ AcOEt/NH4OH = 100:1 ꢀ AcOEt/MeOH/NH4OH =
100:3:1). The purified material was dissolved in AcOEt, and then
HCl/MeOH was added. The precipitated hydrochloric acid salt
was collected by filtration to give the captioned compound as
white powder (283.4 mg, 86%). Mp 225 °C (dec). 1H NMR (CDCl3,
400 MHz, free base) d: 0.12 (2H, m), 0.52 (2H, m), 0.83 (1H, m),
0.91 (3H, t, J = 7.1 Hz), 1.28–1.45 (6H, m), 1.56–1.69 (4H, m), 1.94
(1H, m), 2.13 (1H, ddd, J = 12.2, 12.2, 3.4 Hz), 2.21 (1H, ddd,
J = 12.2, 12.2, 4.4 Hz), 2.36 (2H, d, J = 7.8 Hz), 2.52–2.73 (5H, m),
2.99 (1H, d, J = 18.5 Hz), 3.04 (1H, d, J = 5.4 Hz), 4.19 (1H, d,
J = 7.3 Hz), 5.12 (3H, br s), 6.53 (1H, d, J = 8.1 Hz), 6.63 (1H, d,
J = 8.1 Hz). IR (neat, cmÀ1, free base): 3386, 1638, 1607, 1504,
1149, 1116. MS (FAB) m/z (M+H)+ = 412. Anal. Calcd for
C26H38N2O3Á2HClÁ0.4H2O: C, 61.63; H, 8.12; N, 5.53; Cl, 13.99.
Found: C, 61.69; H, 8.15; N, 5.83; Cl, 13.70.
3-O-t-butyldimethylsilyl-6a-naltrexol (12b, 0.50 g, 1.09 mmol)
was dissolved in CH2Cl2 (10 mL). To the solution, Et3 N (0.43 mL,
3.06 mmol) and MsCl (0.12 mL, 1.53 mmol) were added, and the
solution was stirred for 3 h at 0 °C. To the solution, saturated aque-
ous NH4Cl and AcOEt were added for separation. The organic layer
was washed with water and brine, and was dried over Na2SO4. The
crude 6a-mesylate compound was obtained by concentration.
To the THF solution of n-hexanethiol (0.83 mL, 5.94 mmol), LDA
(1.5 M in THF, 4.0 mL, 6.0 mmol) was added at 0 °C. After 20 min of
stirring, the above crude 6a-mesylate compound dissolved in THF
(3 mL) was added dropwise to the reaction mixture. Stirring was
continued for 6 h at 0 °C. To the reaction mixture, brine and AcOEt
were added for separation. The organic layer was washed with
water and brine, dried over Na2SO4, and then concentrated to give
a crude product. The obtained crude product was purified by silica
gel column chromatography (hexane/EtOAc = 4:1) to give silyl
ether compound 13b.
Deprotection of 13b was conducted in THF (18 mL) using TBAF
(1.0 M in THF, 0.84 mL, 8.4 mmol) catalyzed by two drops of water
at rt. To the reaction mixture, brine and AcOEt were added for sep-
aration. The organic layer was washed with water and brine, dried
over Na2SO4, and then concentrated to give a crude product. The
obtained crude product was purified by silica gel column chroma-
tography (hexane/EtOAc = 1:1) to give a free base of the captioned
product (13c, 0.36 g, 65%). The purified material (0.15 g,
3.38 mmol) was dissolved in AcOEt, and then HCl/MeOH was

9200
K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
added. The precipitated hydrochloric acid salt was collected by fil-
tration to give the captioned compound as white powder (0.12 g,
75%). Mp > 235 °C (dec). 1H NMR (DMSO-d6, 400 MHz) d: 0.40
(1H, m), 0.50 (1H, m), 0.59 (1H, m), 0.67 (1H, m), 0.85 (1H, t,
J = 7.1 Hz), 1.07 (1H, m), 1.20–1.40 (8H, m), 1.45–1.55 (2H, m),
1.60–1.75 (2H, m), 1.85 (1H, m), 2.36 (1H, m), 2.42 (1H, d,
J = 8.1 Hz), 2,60 (1H, dt, J = 12.7, 7.1 Hz), 2.69 (1H, dt, J = 12.7,
7.1 Hz), 2.85 (1H, m), 2.95–3.05 (2H, m), 3.25–3.35 (3H, m), 3.84
(1H, d, J = 4.9 Hz), 4.53 (1H, d, J = 8.1 Hz), 6.33 (1H, s), 6.62 (1H,
d, J = 8.1 Hz), 6.74 (1H, d, J = 8.1 Hz), 8.87 (1H, br s), 9.40 (1H, s).
IR (KBr, cmÀ1): 3247, 1641, 1503, 1118, 1030. MS (FAB) m/z
(M+H)+ = 444. Anal. Calcd for C26H37NO3SÁHClÁ0.15H2O: C, 64.68;
H, 8.00; N, 2.90; Cl, 7.34; S, 6.64. Found: C, 64.29; H, 7.92; N,
2.83; Cl, 7.52; S, 6.39.
J = 8.8 Hz), 6.58 (1H, d, J = 8.3 Hz), 6.64 (1H, d, J = 8.3 Hz). IR
(KBr, cmÀ1): 3375, 1684, 1604, 1504, 1119. MS (FAB) m/z
(M+H)+ = 458. Anal. Calcd for C26H35NO4SÁ0.5(C4H6O6)Á0.15H2O:
C, 63.63; H, 7.050; N, 2.56; S, 5.86. Found: C, 63.58; H, 7.16; N,
2.53; S, 5.71.
4.8.2. S-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,14-
dihydroxymorphinan-6-yl]-3-(furan-3-yl)prop-2-enthioate (23)
tartrate
Yield 63%. Mp 225 °C (dec). 1H NMR (DMSO-d6, 500 MHz) d:
0.15–0.24 (2H, m), 0.45–0.57 (2H, m), 0.84–0.93 (1H, m), 1.23–
1.43 (2H, m), 1.52–1.67 (2H, m), 1.92–2.29 (3H, m), 2.40–2.52
(1H, m), 2.53–2.78 (3H, m), 3.08 (1H, d, J = 19.1 Hz), 3.19–3.30
(1H, m), 4.01 (1H, s), 4.52 (1H, d, J = 8.8 Hz), 6.60 (1H, d,
J = 7.8 Hz), 6.64 (1H, d, J = 7.8 Hz), 6.74 (1H, d, J = 15.6 Hz), 7.01
(1H, d, J = 1.5 Hz), 7.50 (1H, d, J = 15.6 Hz), 7.76 (1H, br s), 8.18
(1H, s), 9.18 (1H, br s). IR (KBr, cmÀ1): 3402, 1665, 1315, 1040.
MS (FAB) m/z (M+H)+ = 480. Anal. Calcd for C27H29NO5SÁ0.5
(C4H6O6)Á0.3H2O: C, 62.19; H, 5.87; N, 2.50; S, 5.73. Found: C,
62.21; H, 5.86; N, 2.57; S, 5.65.
4.8. Synthesis of thioester compounds
4.8.1. S-[(5R,6R)-17-(Cyclopropylmethyl)-4,5-epoxy-3,
14-dihydroxymorphinan-6-yl]hexanthioate (14) tartrate
To the THF (20 mL) solution of PPh3 (1.65 g, 6.3 mmol), DIPAD
(1.2 mL, 5.7 mmol) was added at 0 °C, and the resulting reaction
mixture was stirred for 10 min at the same temperature. To the
reaction mixture, ethanethioic S-acid (0.44 mL, 5.7 mmol) and then
4.9. Synthesis of 3-amino and 3-amido compound
the THF (10 mL) solution of 3-O-methyl-6a-naltrexol (12a, 1.02 g,
4.9.1. (2E)-N-[(5R,6R)-3-Amino-17-(cyclopropylmethyl)-4,5-
epoxy-14-hydroxymorphinan-6-yl]-3-(furan-3-yl)-N-
methylprop-2-enamide (19) tartrate
2.85 mmol) were added. The reaction mixture was allowed to
warm to rt and was stirred for 24 h. After concentration, 1 N HCl
and AcOEt were added to the residue for separation. The organic
layer was washed with 1H HCl. The combined aqueous layer was
made basic using saturated aqueous NaHCO3, and the product
was extracted with AcOEt. The organic layer was dried over
Na2SO4, and concentrated to give a crude product. The crude mate-
rial was purified by silica gel column chromatography (c-hexane/
AcOEt/MeOH = 350:50:5) to give a thioacetyl compound.
The thioacetyl compound (910 mg, 2.19 mmol) was hydrolyzed
with 0.05 N NaOH (6 mL) in MeOH (30 mL) at rt. To the reaction
mixture, aqueous saturated NaHCO3 and CHCl3 were added for sep-
aration. The organic layer was dried over Na2SO4 and concentrated.
Then, the obtained crude product was purified by silica gel column
chromatography (CHCl3/NH4OH = 100:1) to give thiol compound
13a (718 mg, 88%).
Compound 13a (629.5 mg, 1.69 mmol) and Na2SO4 (268 mg,
2.52 mmol) were dissolved in a mixture of THF (10 ml) and water
(10 mL). To the reaction mixture, hexanoyl chloride (318 mg,
2.37 mmol) was added. Acylation was completed by stirring at rt
for 2 h. Aqueous saturated NaHCO3 and AcOEt were added for sep-
aration. The organic layer was dried over Na2SO4 and then concen-
trated. Silica gel column chromatography (CHCl3 ꢀ CHCl3/
MeOH = 200:4 ꢀ 200:5) was performed to produce a thioester
compound.
The deprotection of 3-methylether moiety was conducted with
BBr3 (1.0 M CH2Cl2, 14 mL, 14 mmol) in CHCl3 (20 mL) at 0 °C. The
reaction mixture was poured onto ice water, and then saturated
ammonia, aqueous saturated NaHCO3, and CHCl3 were added
for separation. The organic layer was washed with brine, dried
over Na2SO4, and then concentrated. The crude product was puri-
fied by silica gel column chromatography (CHCl3 ꢀ CHCl3/
MeOH = 40:1) to give a free base of the captioned compound
(14, 403 mg, 55%). The purified material (0.15 g, 3.38 mmol) was
dissolved in MeOH, and then tartaric acid was added. The precip-
itated tartaric acid salt was collected by filtration to give the cap-
tioned compound as white powder. Mp 175–176 °C. 1H NMR
(DMSO-d6, 400 MHz) d: 0.15–0.20 (2H, m), 0.45–0.55 (2H, m),
0.86 (3H, t, J = 6.8 Hz), 0.90 (1H, m), 1.20–1.40 (6H, m), 1.50–
1.60 (4H, m), 1.94 (1H, dt, J = 13.4, 10.7 Hz), 2.11 (1H, m), 2.23
(1H, m), 2.47 (1H, m), 2.57 (2H, t, J = 7.31), 2.60–2.75 (3H, m),
3.05–3.15 (2H, m), 3.25 (1H, br s), 4.03 (1H, s), 4.46 (1H, d,
To the CH2Cl2 (10 mL) solution of 1 (506 mg, 1.1 mmol), pyri-
dine (0.9 mL, 11.1 mmol) and Tf2O (0.35 mL, 2.1 mmol) were added
at 0 °C. After stirring for 30 min at the same temperature, the reac-
tion mixture was poured onto saturated aqueous Na2CO3, and then
Et2O was added for separation. The organic layer was washed with
brine, and then dried over Na2SO4. The crude material obtained by
concentration was purified by silica gel column chromatography to
give 3-triflate.
3-Triflate (160 mg, 0.26 mmol) was dissolved in toluene (7 mL).
To the solution, dppf (37 mg, 0.07 mmol), CsCO3 (253 mg,
0.78 mmol), Pd(dba)2 (47 mg, 0.05 mmol), and benzophenonei-
mine (0.15 mL, 0.89 mmol) were added. The reaction mixture
was heated for refluxing, and then stirred for 6 h. After cooling to
rt, the reaction mixture was poured onto saturated aqueous
Na2CO3, and then AcOEt was added for separation. The organic
layer was washed with brine, and then dried over Na2SO4. The
crude material obtained by concentration was purified by silica
gel column chromatography to give a 3-diphenylmethyleneamino
compound.
The yielded 3-diphenylmethyleneamino compound (122 mg,
0.19 mmol) was dissolved in THF (5 mL), and then 1 N HCl
(1.9 mL) was added. After stirring for 3 h at rt, the reaction mixture
was poured onto saturated aqueous Na2CO3, and then AcOEt was
added for separation. The organic layer was washed with brine,
and then dried over Na2SO4. The crude material, obtained by con-
centration, was purified by silica gel column chromatography to
give a free base of the captioned compound (51%). The free base
was dissolved in MeOH and then L-(+)-tartaric acid was added to
give captioned salt. Mp > 120 °C (dec). 1H NMR (CDCl3, 300 MHz,
free base) d: 0.06–0.20 (2H, m), 0.46–0.60 (2H, m), 0.77–0.94
(1H, m), 1.41–1.73 (3.5H, m), 2.08–2.37 (3.25H, m), 2.37 (2H, d,
J = 6.6 Hz), 2.55–2.70 (2.25H, m), 2.96–3.17 (2H, m), 3.03 (3H, s),
3.40 (2H, br s), 3.72–3.84 (0.75H, m), 4.47–4.64 (0.5H, m), 4.57
(0.75H, d, J = 8.0 Hz), 6.40 (0.75H, d, J = 15.4 Hz), 6.51–6.67
(3.25H, m), 7.39 (0.75H, s), 7.42 (0.25H, s), 7.52 (0.75H, d,
J = 15.4 Hz), 7.54 (0.25H, d, J = 15.4 Hz), 7.61 (1H, s). IR (KBr,
cmÀ1, free base): 3345, 1652, 1157, 1112. MS (EI, free base) m/z
(M)+ = 475. Anal. Calcd for C28H33N3O4Á1.8(C4H6O6)Á0.2H2O: C,
56.48; H, 6.11; N, 5.56. Found: C, 56.42; H, 5.95; N, 5.61.

K. Kawai et al. / Bioorg. Med. Chem. 16 (2008) 9188–9201
9201
4.9.2. (2E)-N-[(5R,6R)-3-Acetamido-17-(cyclopropylmethyl)-
4,5-epoxy-14-hydroxymorphinan-6-yl]-3-(furan-3-yl)-N-
methylprop-2-enamide (20) tartrate
The test compound was administered sc into the rostral back of the
animals or po 15 min before the administration of acetic acid.
To the CH2Cl2 (5 mL) solution of compound 19 (66 mg,
0.14 mmol), pyridine (0.023 mL, 0.28 mmol) and Ac2O (0.015 mL,
0.16 mmol) were added at 0 °C. After stirring for 3 h at the same
temperature, the reaction mixture was poured onto saturated
aqueous Na2CO3, and then AcOEt was added for separation. The or-
ganic layer was washed with brine, and then dried over Na2SO4.
The crude material, obtained by concentration, was purified by sil-
ica gel column chromatography to give a free base of the captioned
Acknowledgments
We thank Dr. Katsuhiko Iseki, Dr. Hidenori Mochizuki, and Dr.
Kaoru Nakao (Toray, Kamakura) for helpful discussions.
References and notes
1. Szmuszkovicz, J.; Von Voigtlander, P. F. J. Med. Chem. 1982, 25, 1125.
2. Costello, G. F.; Martin, B. G.; Barlow, J. J.; Carroll, J. A.; Shaw, J. S. Eur. J.
Pharmacol. 1988, 151, 475.
compound (58%). The free base was dissolved in MeOH and then L-
(+)-tartaric acid was added to give captioned salt. Mp > 135 °C
(dec). 1H NMR (CDCl3, 300 MHz, free base) d: 0.08–0.21 (2H, m),
0.49–0.60 (2H, m), 0.77–0.93 (1H, m), 1.37–1.79 (4H, m), 1.70
(2.1H, s), 2.04–2.35 (3H, m), 2.15 (0.9H, s), 2.39 (2H, d,
J = 6.6 Hz), 2.58–2.73 (2H, m), 3.00–3.17 (2H, m), 3.06 (2.1H, s),
3.14 (0.9H, s), 3.74–3.84 (0.7H, m), 4.45–4.58 (0.3H, m), 4.59
(0.3H, d, J = 8.0 Hz), 4.62 (0.7H, d, J = 8.0 Hz), 5.11 (1H, br s),
6.22–6.31 (1.4H, m), 6.59–6.80 (1.6H, m), 6.98 (0.7H, br s), 7.40–
7.47 (1H, m), 7.51–7.76 (2.3H, m), 7.64 (0.3H, br s), 8.17 (0.7H, d,
J = 8.2 Hz). IR (KBr, cmÀ1, free base): 3410, 1683, 1652, 1604,
1425, 1412. MS (EI, free base) m/z (M)+ = 517. Anal. Calcd for
C30H35N3O5ÁC4H6O6Á2.6H2O: C, 57.43; H, 6.26; N, 5.66. Found: C,
57.17; H, 6.52; N, 5.88.
3. Haifpenny, P. R.; Horwell, D. C.; Hughes, J.; Hunter, J. C.; Rees, D. C. J. Med. Chem.
1990, 33, 286.
4. Millan, M. J. Trends Pharmacol. Sci. 1990, 11, 70.
5. Giardina, G.; Clarke, G. D.; Dondio, G.; Petrone, G.; Sbacchi, M.; Vecchietti, V. J.
Med. Chem. 1994, 37, 3482.
6. Nagase, H.; Kawai, K.; Kawamura, K.; Hayakawa, J.; Endo, T. Chem. Abstr. 1994,
120, 164625. WO 93/15081, 1993.
7. Nagase, H.; Hayakawa, J.; Kawamura, K.; Kawai, K.; Takezawa, Y.; Matsuura, H.;
Tajima, C.; Endo, T. Chem. Pharm. Bull. 1998, 46, 366.
8. Portoghese, P. S.; Lipkowski, A. W.; Takemori, A. E. J. Med. Chem. 1987, 30, 238.
9. Portoghese, P. S.; Sultana, M.; Nagase, H.; Takemori, A. E. J. Med. Chem. 1988, 31,
281.
10. Nogrady, T. In Medicinal Chemistry, a Biochemical Approach; Oxford University
Press: New York, 1985; p 68.
11. Portoghese, P. S.; Nagase, H.; Takemori, A. E. J. Med. Chem. 1988, 31, 1344.
12. Lin, C.-E.; Takemori, A. E.; Portoghese, P. S. J. Med. Chem. 1993, 36, 2412.
13. Mohamed, M. S.; Larson, D. L.; Takemori, A. E.; Portoghese, P. S. J. Med. Chem.
1986, 29, 1551.
14. Casy, F. A.; Parfitt, T. R. In Opioid Analgesics, Chemistry and Receptors; Plenum
Press: New York, 1986; pp 9–104.
4.10. Opioid receptor selectivity assay
15. Chatterjie, N.; Inturrisi, C. E. J. Med. Chem. 1975, 18, 490.
16. Lai, J.-Y.; Yu, J.; Hawkins, R. D.; Falck, J. R. Tetrahedron Lett. 1995, 36, 5691.
17. Sayre, M. L.; Portoghese, P. S. J. Org. Chem. 1980, 45, 3366.
18. Shook, J. E.; Pelton, J. T.; Wire, W. S.; Hirning, L. D.; Hruby, V. J.; Burks, T. F. J.
Pharmacol. Exp. Ther. 1987, 240, 772.
19. Endoh, T.; Matsuura, H.; Tajima, A.; Izumimoto, N.; Tajima, C.; Suzuki, T.;
Saitoh, A.; Suzuki, T.; Narita, M.; Tseng, L. F.; Nagase, H. Life Sci. 1999, 65, 1685.
20. Kanematsu, K. Yakugaku Zasshi 1998, 118, 1.
21. Katsumata, S.; Ienaga, Y.; Minami, M.; Nakagawa, T.; Kanematsu, K.; Satoh, M.
Eur. J. Pharmacol. 1996, 312, 349.
22. Hosoki, R.; Niizawa, S.; Koike, K.; Sagara, T.; Kanematsu, K.; Takayanagi, I. Arch.
Int. Pharmacodyn. Ther. 1996, 331, 136.
Each vas deferens isolated from male ddy strain mice was hung
in a Magnus tube, which was maintained at 37 °C, filled with a Kre-
bes Henseleit solution (118 mM NaCl, 4.7 mM KCl, 2.5 mM CaCl2,
1.1 mM KH2PO4, 25 mM NaHCO3, 11 mM glucose), and aerated
with 5% CO2 and 95% O2. Electric stimulation was applied through
upper and lower ring-shaped platinum electrodes (0.1 Hz, 5.0 mS)
using the NIHON KOHDEN SEN-7203 electric stimulation system
and NIHON KOHDEN SEG-3104 amplifier. Tissue contraction was
recorded on a polygraph using an isometric transducer (NIHON
KOHDEN WT-687G).
23. Bardo, M. T.; Miller, J. S.; Neisewander, J. L. Pharmacol. Biochem. Behav. 1984, 21,
545.
24. Nock, B. In The Pharmacology of Opioid Peptides; Harwood Academic Publishers:
Singapore, 1995; pp 25–59.
25. Nock, B.; Giordano, A. L.; Cicero, T. J.; O’Connor, L. H. J. Pharmacol. Exp. Ther.
1990, 254, 412.
26. Suzuki, T.; Shiozaki, Y.; Masukawa, Y.; Misawa, M.; Nagase, H. Jpn. J. Pharmacol.
1992, 58, 435.
27. Funada, M.; Suzuki, T.; Narita, M.; Misawa, M.; Nagase, H. Neuropharmacology
1993, 32, 1315.
28. Tsuji, M.; Takeda, H.; Matsumiya, T.; Nagase, H.; Narita, M.; Suzuki, T. Life Sci.
2001, 68, 1717.
29. The detailed results and experimental method were described in Ref. 28.
30. Togashi, Y.; Umeuchi, H.; Okano, K.; Ando, N.; Yoshizawa, Y.; Honda, T.;
Kawamura, K.; Endoh, T.; Utsumi, J.; Kamei, J.; Tanaka, T.; Nagase, H. Eur. J.
Pharmacol. 2002, 435, 259.
Each test compound was added in a cumulative manner to
determine the IC50 values (concentration for 50% inhibition of con-
traction induced by electric stimulation). Next, a solution of antag-
onists selective for each type of opioid receptor was initially added
to the system, and 20 min later, a test compound was added in a
cumulative manner. According to the above procedure, the ratio
of the IC50 values of the test compound in the presence of the selec-
tive antagonists to that in the absence of the selective antagonists
was determined.
4.11. Acetic acid writhing method
31. Umeuchi, H.; Togashi, Y.; Honda, T.; Nakao, K.; Okano, K.; Tanaka, T.; Nagase, H.
Eur. J. Pharmacol. 2003, 477, 29.
Male mice (5 weeks old) were used in this test. After ip-admin-
istration of 0.1 mL of 0.6% aqueous AcOH per 10 g of body weight,
the number of writhing reactions occurring in 10 min starting from
10 min after the ip-administration was evaluated as the indicator.
32. Wakasa, Y.; Fujiwara, A.; Umeuchi, H.; Endoh, T.; Okano, K.; Tanaka, T.; Nagase,
H. Life Sci. 2004, 75, 2947.
33. Umeuchi, H.; Kawashima, Y.; Aoki, C. A.; Kurokawa, T.; Nakao, K.; Itoh, M.;
Kikuchi, K.; Kato, T.; Okano, K.; Gershwin, M. E.; Miyakawa, H. Eur. J. Pharmacol.
2005, 518, 133.