Regio- and stereoselective syntheses of the natural product CCR5 antagonist anibamine and its three olefin isomers

Article abstract of DOI:10.1021/jo2013669

The syntheses of the natural product anibamine and its three olefin isomers have been achieved concisely and efficiently via highly regio- and stereoselective reactions. The crucial steps included a regioselective palladium-catalyzed alkynylation by Sonogashira coupling and a stereoselective Suzuki coupling. Further conformation analyses and in vitro calcium mobilization studies were carried out to characterize the compounds' biological properties.

Full text of DOI:10.1021/jo2013669

ARTICLE
pubs.acs.org/joc
Regio- and Stereoselective Syntheses of the Natural Product CCR5
Antagonist Anibamine and its Three Olefin Isomers
Feng Zhang, Saheem Zaidi, Kendra M. Haney, Glen E. Kellogg, and Yan Zhang*
Department of Medicinal Chemistry, Virginia Commonwealth University, 800 East Leigh Street, Richmond, Virginia 23298,
United States
S Supporting Information
b
ABSTRACT:
The syntheses of the natural product anibamine and its three olefin isomers have been achieved concisely and efficiently via highly
regio- and stereoselective reactions. The crucial steps included a regioselective palladium-catalyzed alkynylation by Sonogashira
coupling and a stereoselective Suzuki coupling. Further conformation analyses and in vitro calcium mobilization studies were carried
out to characterize the compounds’ biological properties.
’ INTRODUCTION
Anibamine, a pyridine quarternary alkaloid isolated from
Aniba panurensis,1,2 has been identified as a chemokine receptor
CCR5 antagonist with an IC50 of 1 μM in inhibiting the binding
of 125I-gp120 to the CCR5 receptor. Anibamine has a novel
structural skeleton compared with other small molecule CCR5
antagonists identified through high-throughput screenings, such
as Vicriviroc,3 Maraviroc,4 and TAK-7795 (Figure 1), all of which
have been studied in anti-HIV therapeutics development.6
Recent studies7 also demonstrate that anibamine inhibits pros-
tate cancer cell proliferation, adhesion, and invasion at micro-
molar to submicromolar levels. Preliminary in vivo studies
further indicate that anibamine also inhibits prostate tumor
growth in mice. Correspondingly, it has been found that the
chemokine CCL5 and its receptor CCR5 may play important
roles in cancer progression8 and TAK-779 blocked CCL5-in-
duced invasion and proliferation of prostate cancer cells.9 There-
fore, anibamine may serve as a new lead for the development
of CCR5 antagonists with potential applications in both AIDS
and cancer therapies.
Figure 1. Anibamine and some known CCR5 antagonists.
The first total synthesis of anibamine has been recently
reported by our group.10 In this approach, the two ten-carbon
side chains were introduced via the Wittig reagent of 1-bromo-
nonane and the 3,5-dialdehyde pyridine intermediate. Four
isomers were obtained as a mixture from this reaction and were
used in the next few steps without separation. At the last step,
anibamine was isolated by preparative HPLC with 8% overall
yield (10 steps). This synthetic route suffered from tedious
separations in the last few steps and relatively low yield due to
the limited stereoselectivity of the Wittig reaction. At that time,
the difficulties in obtaining the other isomers of anibamine
Figure 2. Anibamine and its three isomers.
(2, 3 and 4, Figure 2) prevented us from studying the effects
of the double bond configuration and resulting conformation on
Received: July 7, 2011
Published: August 29, 2011
r
2011 American Chemical Society
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the biological activities of the molecules. Here we report new,
highly regio- and stereoselective syntheses of anibamine and its
three olefin isomers in a concise and efficient manner.
The retrosynthetic analysis of anibamine is depicted in
Scheme 1. In this route, the two double bonds will be introduced
stereoselectively by adopting different Suzuki coupling condi-
tions while a regio-selective Sonogashira coupling will be applied
to introduce the side chain at the 2-position and form the five-
member ring system.
’ RESULTS AND DISCUSSION
The synthesis was initiated (Scheme 2) from commercially
available 2-amino-4,6-dimethylpyridine that was brominated in
glacial acetic acid to give the desired 3,5-dibromo-4,6-dimethyl-
2-aminopyridine (5) in 75% yield.11 Diazotization of 5 under
routine condition with Br2/NaNO2 in 48% HBr as solvent did
not yield the desired product 6 due to the poor solubility of the
starting material. Cosolvents such as DMSO12 or 1,4-dioxane13
were added with limited success. However, a modified Sand-
meyer reaction14 by treating 5 with tert-butyl nitrite/CuBr2 in
CHBr3 as the solvent obtained the desired product 6 in a
reasonable yield. The reaction was further improved to a yield
of 88% by replacing CuBr2 with Br2.
Scheme 1. Retrosynthetic Analysis of Anibamine
The regioselective synthesis of the key intermediate 2-alkynyl-
3,5-dibromo-4,6-dimethylpyridine (7) was achieved by reacting
6 with terminal acetylenes under palladium-catalyzed Sonogashira
conditions15 with 91% yield (Scheme 2). To ascertain the regio-
chemistry of the coupling product 7, it was hydrogenated over
palladium/carbon to give 8. Simultaneously, 8 was prepared by
another method starting with 2-amino-4,6-dimethylpyridine.
The corresponding 2-bromopyridine (9) was obtained in a
reasonable yield by diazotization in a bromine and 48% hydro-
bromic acid mixture.16 Further treatment of 9 with propargyl
Scheme 2. Preparation of Intermediate 7
Scheme 3. Synthesis of Anibamine
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Scheme 4. Synthesis of (11E, 22E)-Anibamine
To stereoselectively introduce the two aliphatic side chains
onto positions 3 and 5 of intermediate 11, excess organoborane
reagent was used under Suzuki coupling conditions. Recent
development17 on the utilization of alkyl- and alkenylboronic
acids and esters suggested a convenient method for the prepara-
tion of diisopropyl (Z)-1-decenylboronate (12). Under standard
Suzuki reaction conditions,18 1.0 equiv of 11 and 4.0 equiv of 12
were coupled in the presence of Pd(OAc)2, PPh3 and Na2CO3 in
a mixture of solvents (toluene/EtOH/water = 2:1:1) at refluxing
temperature for 6 h. Compound 13 was obtained stereoselec-
tively in an excellent yield. The crude 1H NMR and 13C NMR of
the reaction showed no observable stereoisomers.
Scheme 5. Synthesis of (11Z, 22E)-Anibamine and (11E,
22Z)-Anibamine
Subsequently, the PMB group of 13 was removed under acidic
conditions to give compound 14 in 80% yield. The ring closure
was achieved by treating 14 with methanesulfonylchloride and
triethylamine at room temperature to give the natural product
anibamine (1) in 71% yield (Scheme 3). The spectral properties
of the synthesized target compound 1 were identical to those of
the natural product.1
The (11E, 22E) isomer of anibamine (2) was prepared in a
similar fashion to anibamine. (E)-dec-1-Enylboronic acid (15)
was readily obtained by the hydroboration of 1-decyne with
BHBr2 SMe2, followed by hydrolysis.19 Under the same Suzuki
3
cross-coupling reaction conditions, 1.0 equiv of 11 and 4.0 equiv
of 15 were reacted to give the intermediate 16 stereoselectively in
an excellent yield. Then, by following the same procedure
described for 1, the (11E, 22E) isomer 2 was obtained in 64%
yield via two steps from compound 16 (Scheme 4).
Both electronic and steric considerations suggest that the
regioselective introduction of the two side chains of isomers 3
and 4 would be challenging due to the similar reactivity of the two
bromo-substitutions at the 3- and 5-positions of intermediate 11
toward coupling reactions. The electronic effects arising from
substitutions on the pyridinyl ring system are similar and the
steric hindrance effects of the bulky 2-position OPMB group
would be diminished due to the relatively long aliphatic chain
connection to the parent ring. Unsurprisingly, Suzuki coupling of
11 with an equivalent of 15 with varied temperatures and solvent
systems gave products 18 and 19 in roughly similar amounts. The
successful chromatographic separation of the two isomers, how-
ever, allowed the preparation of 3 and 4 in reasonably good yields
(Scheme 5).
To predict the influence of the double bond configuration of
1À4 with respect to interaction with the receptor CCR5, in silico
conformation analyses were conducted. As shown in Figure 3,
the conformations of the core portions of all four isomers were
similar with varied, but somewhat kinked, side chain orientations.
Overall, however, their molecular shapes were quite similar and
almost overlapped. To validate such results from the conforma-
tion analyses as to if the binding affinity of these isomers to the
alcohol under palladium-catalyzed Sonogashira conditions gave
the alkynylated pyridine 10 in 80% yield. Catalytic hydrogena-
tion of the triple bond15a afforded the pyridylpropanol, whose
NMR spectra were unequivocally consistent with the product 8.
Thus, the regio-selective synthesis of 7 via a Sonogashira coupl-
ing condition was confirmed.
Next, the alkynyl bond of 7 was chemo-selectively reduced
while minimizing the possible reductive debromination pro-
duct.15a The hydrogenation of 7 over platinum oxide in ethanol
was stopped after 2 equivalents of hydrogen were consumed
yielding the key intermediate 3,5-dibromo-2-substituted-4,6-
dimethylpyridine (11) in 73% yield (Scheme 3).
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Figure 3. Conformation analyses of compound 1 (A), 2 (B), 3 (C), and 4 (D).
Table 1. Calcium Mobilization Inhibition Assay Results of All
the Four Isomersa
not critical for binding to the receptor. These results shed light on
a possible conserved binding mode of these ligands to the
receptor and will facilitate our next step molecular design to
identify novel anibamine derivatives as the chemokine receptor
CCR5 antagonists and potential anti-HIV and anticancer agents.
compound
1
2
3
4
IC50
5.43
0.91
6.53
1.79
9.23
0.59
10.09
3.87
SEM
a Values shown were from at least three separate experiments performed
in triplicate. The IC50 values were calculated using Prism.
’ EXPERIMENTAL SECTION
General Information and Methods. All reagents were used
directly as obtained commercially unless otherwise noted. Melting
points were determined on a melting point apparatus and are uncor-
receptor CCR5 would be influenced, further biological assay is
deemed to be conducted.
1
rected. H NMR and 13C NMR spectra were taken on a 400 MHz
To experimentally characterize the influence of the double
bond configuration of compounds 1À4 on their affinity to the
receptor, the calcium mobilization assay20 was adopted by using
CCR5MOLT-4 cell lines. The IC50 values of the calcium reflux
inhibitory effect for all four isomers are summarized in Table 1.
First, the comparable IC50 of anibamine (1) to its inhibitory
binding affinity of RANTES at the receptor (1.0 μM) validated
the calcium mobilization assay protocol. Second, not surpris-
ingly, all four isomers showed similar inhibitory effect on calcium
reflux, which indicates that their binding affinity, as well as
possibly their binding mode to the receptor, is comparable. This
supports the conformation analyses results: the double bond
configuration does not significantly influence the overall con-
formation of the whole molecule because of the two long
aliphatic chains.
spectrometer and tetramethylsilane was used as an internal standard.
Infrared spectra were obtained on a FT-IR spectrometer. LC-MS was
performed on a QTOF-2 instrument using ESI ion source. High-
Resolution mass spectral analyses were performed on a QTOF-2
instrument using ESI ion source operated in positive ion mode. Column
chromatography was performed on silica gel (grade 60 mesh). Pre-
parative thin-layer chromatography (TLC) was performed on silica gel
GF plates (1000 μm, 20 Â 20 cm).
3,5-Dibromo-4,6-dimethylpyridin-2-amine (5). A solution of
2-amino-4,6-dimethylpyridine (2.44 g, 20 mmol) in 15 mL of glacial
acetic acid under nitrogen was treated with a solution of 7.36 g
(46 mmol) Br2 in 5 mL of glacial acetic acid over 15 min. The solution
became a solid mass and was allowed to stand at r.t. for 1 h. After cooling
in an ice bath, the material was made alkaline with 20% cold NaOH
solution. Then the mixture was extracted with CH2Cl2 (3 Â 50 mL), the
combined organic layer was dried over anhydrous Na2SO4, filtered and
concentrated. The residue was purified on silica gel (Hexane/EtOAc,
2:1À1:1) to afford the product (4.21 g, 75%) as a yellow solid. Mp
136À137 °C. (lit.11 Mp 136À136.5 °C). IR (KBr, cmÀ1) νmax: 3459,
3283, 3124, 1628, 1428, 659. 1H NMR (400 MHz, CDCl3) δ 4.86 (br,
2H), 2.53 (s, 3H), 2.49 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 153.9,
153.6, 147.0, 111.5, 103.9, 25.2, 24.3.
2,3,5-Tribromo-4,6-dimethylpyridine (6). To a solution of 5
(556 mg, 2 mmol) and Br2 (384 mg, 2.4 mmol) in bromoform (6 mL),
was added dropwise BuNO2 (618 mg, 6 mmol) at r.t. The solution
was stirred at r.t. for 2 h. Then the solution was stopped by addition
of saturated Na2CO3 solution, followed by extraction with EtOAc
(3 Â 40 mL). The combined organic layers were dried over anhydrous
’ CONCLUSION
In conclusion, the regio- and stereoselective total synthesis of
anibamine has been achieved in 7 steps with an overall yield of
23%, which is a 3-fold improvement over previous results. Its
three isomers were also obtained in similar yields. The metho-
dology described above for the preparation of intermediate 7
and 11 will allow more convenient synthesis of a variety of
anibamine derivatives for our further biological evaluations and
structureÀactivity relationship studies. Conformational analyses
of 1À4 are supported by the calcium mobilization screens, which
together, suggest that the confirguration of the double bond may
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Na2SO4, filtered and concentrated. The residue was purified on silica gel
(Hexane/EtOAc, 40:1) to afford the product (600 mg, 88%) as a pale-
1127, 825. 1H NMR (400 MHz, CDCl3) δ 7.13 (s, 1H), 6.92 (s, 1H),
2.48 (s, 3H), 2.28 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 159.4, 150.2,
141.4, 125.6, 123.3, 24.0, 20.6. (lit.16)
yellow solid. Mp 124À125 °C. (lit.16 Mp 124À125 °C). IR (KBr, cmÀ1
)
νmax: 1535, 1373, 1241, 1045, 847. 1H NMR (400 MHz, CDCl3) δ 2.68
(s, 3H), 2.63 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 156.6, 149.6,
141.6, 123.3, 123.0, 26.1, 25.4.
3-(4,6-Dimethylpyridin-2-yl)prop-2-yn-1-ol (10). A solution
of 9 (370 mg, 2 mmol), prop-2-yn-1-ol (168 mg, 3 mmol), CuI (19 mg,
0.1 mmol) and piperidine (510 mg, 6 mmol) in 10 mL THF was purged
by the passage of nitrogen through the solution, and 140 mg (0.2 mmol)
of PdCl2(PPh3)2 was added all at once. The reaction mixture was stirred
at room temperature for 3 h. Then the mixture was diluted with EtOAc,
washed with water, saturated brine and dried with Na2SO4, filtered and
concentrated. The residue was purified on silica gel (EtOAc) to afford
the product (257 mg, 80%) as a white solid. Mp 93À94 °C. IR
(KBr, cmÀ1) νmax: 3195, 2916, 1604, 1025, 850. 1H NMR (400 MHz,
CDCl3) δ 7.10 (s, 1H), 6.94 (s, 1H), 4.52 (br s, 2H), 2.79 (br s, 1H),
2.50 (s, 3H), 2.29 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 158.6, 147.8,
141.7, 125.2, 124.0, 87.1, 84.9, 51.3, 24.2, 20.7. HRMS m/z calcd for
C10H12NO [M + H]+ = 162.0919, found 162.0909.
2-(3-(4-Methoxybenzyloxy)prop-1-ynyl)-3,5-dibromo-4,6-
dimethylpyridine (7). To a solution of p-methoxybenzylalcohol (3.32
g, 24 mmol) in anhydrous Et2O (24 mL) was added NaH (60%) (100
mg, 2.4 mmol) at r.t. under N2. After stirring for 30 min, the mixture was
cooled to 0 °C and trichloroacetonitrile (3.46 g, 24 mmol) was added.
The resulting mixture was allowed to warm up slowly to room tempera-
ture and stirred for 4 h. After concentrated to remove Et2O, the residue
was dissolved in hexane (28 mL) and MeOH (0.12 mL). The suspension
was filtered through Celite. The filtrate was concentrated to give a yellow
oil (6.68 g). The crude intermediate was dissolved in anhydrous
dichloromethane (25 mL). Propargyl alcohol (896 mg, 16 mmol) was
added to the reaction and the solution was cooled to 0 °C and treated
with a catalytic amount of 10-camphorsulfonic acid. The reaction was
allowed to warm up slowly to r.t. and stirred overnight under N2
protection. The solution was filtered, washed with saturated aqueous
NaHCO3, dried over anhydrous Na2SO4, filtered and concentrated. The
crude product was purified on silica gel (Hexane/EtOAc, 8:1) to afford
1-methoxy-4-((prop-2-ynyloxy)methyl)benzene (2.42 g, 86%) as a pale-
yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.28 (m, 2H), 6.88 (m, 2H),
4.54 (s, 2H), 4.13 (d, J = 2.4 Hz, 2H), 3.79 (s, 3H), 2.45 (t, J = 2.4 Hz,
1H). (lit.10)
A solution of 6 (682 mg, 2.0 mmol), 1-methoxy-4-((prop-2-ynyloxy)
methyl)benzene (422 mg, 2.4 mmol), CuI (19 mg, 0.1 mmol) and
piperidine (510 mg, 6.0 mmol) in 15 mL THF was purged by the passage
of nitrogen through the solution, and 140 mg (0.2 mmol) of PdCl2-
(PPh3)2 was added all at once. The reaction mixture was stirred at room
temperature for 1 h. Then the mixture was diluted with EtOAc, washed
with water, saturated brine and dried over anhydrous Na2SO4, filtered
and concentrated. The residue was purified on silica gel (Hexane/
EtOAc, 8:1) to afford the product (797 mg, 91%) as a pale-yellow oil. IR
(KBr, cmÀ1) νmax: 2921, 2850, 1736, 1512, 1359, 1245, 1043, 818. 1H
NMR (400 MHz, CDCl3) δ 7.33 (m, 2H), 6.89 (m, 2H), 4.67 (s, 2H),
4.43 (s, 2H), 3.81 (s, 3H), 2.65 (s, 3H), 2.64 (s, 3H). 13C NMR (100
MHz, CDCl3) δ 159.5, 156.6, 147.4, 140.8, 129.9, 129.9, 129.4, 123.8,
123.1, 113.9, 113.9, 90.3, 84.7, 71.3, 57.3, 55.3, 25.8, 24.8. HRMS m/z
calcd for C18H18Br2NO2 [M + H]+ = 437.9704, found 437.9691.
3-(4,6-Dimethylpyridin-2-yl)propan-1-ol (8). Hydrogenation
was conducted on a mixture of compound 7 (131 mg, 0.3 mmol), Pd/C
(13 mg, 10%) in 16 mL MeOH/EtOAc (1:1) under 60 psi. H2
overnight. The reaction mixture was filtered and concentrated. The
residue was purified on silica gel (DCM/MeOH, 10:1) to afford the
product (45 mg, 91%) as a pale-yellow oil. IR (KBr, cmÀ1) νmax: 3262,
2922, 2864, 1610, 1451, 1058, 843. 1H NMR (400 MHz, CDCl3) δ 6.83
(s, 2H), 4.55 (br s, 1H), 3.73 (t, J = 5.6 Hz, 2H), 2.92 (t, J = 6.4 Hz, 2H),
2.48 (s, 3H), 2.28 (s, 3H), 1.92À1.98 (m, 2H). 13C NMR (100 MHz,
CDCl3) δ 160.2, 156.9, 148.5, 121.8, 121.2, 62.6, 35.6, 31.3, 23.7, 20.9.
HRMS m/z calcd for C10H16NO [M + H]+ = 166.1232, found 166.1219.
2-Bromo-4,6-dimethylpyridine (9). To a solution of 2-amino-
4,6-dimethylpyridine (610 mg, 5 mmol) in 2.5 mL HBr (48%), was
added Br2 (2.21 g, 13.8 mmol) at À10 °C, keeping the temperature
below 0 °C. NaNO2 (0.86 g, 12.5 mmol) was added with the reaction
temperature being kept below 0 °C. After a further 30 min, NaOH (2 g in
2 mL water) was added, keeping the temperature below 10 °C and then
more NaOH was added to make the solution strongly alkaline. Extracted
with EtOAc (3 Â 50 mL) and the combined organic layer was dried over
anhydrous Na2SO4, filtered and concentrated, the residue was purified
on silica gel (Hexane/EtOAc, 6:1) to afford the product (626 mg, 68%)
as a pale-yellow oil. IR (KBr, cmÀ1) νmax: 2922, 1597, 1540, 1274, 1191,
3-(4,6-Dimethylpyridin-2-yl)propan-1-ol (8). A solution of
10 (200 mg, 1.24 mmol) in 10 mL of ethanol and 0.2 mL of
triethylamine was hydrogenated over 20 mg (0.09 mmol) of PtO2
overnight. The reaction mixture was filtered and concentrated. The
residue was purified on silica gel (DCM/MeOH, 10:1) to afford the
1
product (187 mg, 91%) as a pale yellow oil. H NMR (400 MHz,
CDCl3) δ 6.81 (s, 2H), 5.05 (br s, 1H), 3.71 (t, J = 5.7 Hz, 2H), 2.90
(t, J = 6.5 Hz, 2H), 2.47 (s, 3H), 2.27 (s, 3H), 1.91À1.98 (m, 2H). The
NMR spectra were unequivocally consistent with the product 8.
2-(3-(4-Methoxybenzyloxy)propyl)-3,5-dibromo-4,6-di-
methylpyridine (11). A solution of 7 (746 mg, 1.71 mmol) in 10 mL
of ethanol and 0.2 mL of triethylamine was hydrogenated over 16 mg
(0.07 mmol) of PtO2 for 1 h. The reaction mixture was filtered and
concentrated. The residue was purified on silica gel (Hexane/EtOAc,
8:1) to afford the product (547 mg, 73%) as pale-yellow oil. IR
(KBr, cmÀ1) νmax: 2930, 2851, 1612, 1511, 1360, 1244, 1098, 1036,
818. 1H NMR (400 MHz, CDCl3) δ 7.26 (m, 2H), 6.86 (m, 2H), 4.45
(s, 2H), 3.80 (s, 3H), 3.54 (t, J = 6.5 Hz, 2H), 2.97À3.01 (m, 2H), 2.61
(s, 3H), 2.60 (s, 3H), 2.00À2.07 (m, 2H). 13C NMR (100 MHz, CDCl3)
δ 159.1, 157.7, 155.1, 146.6, 130.8, 129.2, 129.2, 121.4, 121.0, 113.7,
113.7, 72.4, 69.5, 55.3, 34.7, 28.3, 25.6, 24.8. HRMS m/z calcd for
C18H22Br2NO2 [M + H]+ = 442.0017, found 442.0003.
Diisopropyl (Z)-1-Decenylboronate (12). To a solution of
1-decyne (1.38 g, 10 mmol) in acetone (50 mL) was added NBS
(3.56 g, 20 mmol) and AgNO3 (170 mg, 1 mmol) at r.t. with protection
from light. After 4 h, the solvent was carefully removed under reduced
pressure, diluted with hexane and filtered. The filtrate was concentrated
and purified on silica gel (Hexane) to afford 1-bromo-1-decyne (1.84 g,
85%) as a colorless oil.
To a solution of 1-bromo-1-decyne (1.84 g, 8.49 mmol) in CH2Cl2
(10 mL) in a 100 mL round-bottom flask surrounded by a water bath
under argon, was slowly added a solution of BHBr2 Me2S (1 M in
3
CH2Cl2, 8.49 mL). After stirring of the reaction mixture overnight,
pentane (8.49 mL) was added and the water bath was replaced with an
iceÀwater bath. Isopropyl alcohol (33.96 mmol) was slowly introduced
to the flask and stirring is continued for an additional 15 min. Then the
mixture was concentrated to remove off CH2Cl2, the pentane layer was
separated, the alcohol layer was extracted with pentane. The combined
pentane extracts were concentrated to get diisopropyl (Z)-(1-bromo-1-
decenyl)boronate.
To an ice-cooled solution of diisopropyl (Z)-(1-bromo-1-decenyl)-
boronate in THF (10 mL) in a 100 mL round-bottom flask was added,
with stirring, a solution of KIPBH (1 M in THF, 8.49 mL) dropwise. The
cold bath was then removed, and the stirring was continued at r.t. for 1 h.
Then the mixture was filtered and concentrated, the residue was purified
on silica gel (Hexane/EtOAc, 4:1) to afford diisopropyl (Z)-1-decenyl
boronate (1.31 g, 58%) as a colorless oil. The product was used for next
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step without further purification. IR (KBr, cmÀ1) νmax: 2923, 2854,
1621, 1418, 1337, 1246, 733. 1H NMR (400 MHz, CD3Cl3) δ 6.61 (dt,
J = 7.5, 13.6 Hz, 1H), 5.42 (dt, J = 1.3, 13.6 Hz, 1H), 2.55 (m, 2H),
1.16À1.43 (m, 26H), 0.88 (t, J = 6.7 Hz, 3H); 13C NMR (100 MHz,
CD3Cl3): δ 158.9, 151.1, 65.6, 60.4, 31.9, 31.9, 29.6, 29.5, 29.4, 29.3,
29.29, 29.27, 25.4, 24.6, 22.6, 14.1.
NH4Cl (17 mL) was added, and a voluminous white precipitate formed,
CH2Cl2 was removed under reduced pressure. The (E)-decene-boronic
acid was filtered and washed extensively with iceÀwater, afford (E)-dec-1-
enylboronic acid (784 mg, 85%) as a white solid. The product was directly
used for next step without any further purification. Mp 52À53 °C. IR
1
(KBr, cmÀ1) νmax: 3443, 3322, 2921, 2848, 1634, 1346, 1151, 991. H
NMR (400 MHz, CD3OD) δ 6.52 (dt, J = 6.6, 17.6 Hz, 1H), 5.55 (dt, J =
1.4, 17.6 Hz, 1H), 4.79 (s, 2H), 2.14 (m, 2H), 1.22À1.43 (m, 12H), 0.90 (t,
J = 6.7 Hz, 3H); 13C NMR (100 MHz, CD3OD): δ 154.0, 152.3, 37.0, 33.0,
30.6, 30.4, 30.3, 29.7, 23.7, 14.4.
2-(3-(4-Methoxybenzyloxy)propyl)-3,5-di((Z)-dec-1-enyl)-
4,6-dimethylpyridine (13). Pd(OAc)2 (9 mg, 0.04 mmol), PPh3 (32
mg, 0.12 mmol), and 11 (149 mg, 0.34 mmol) were stirred in toluene
(1.36 mL) and aq Na2CO3 (0.68 mL, 2M), under a nitrogen atmosphere
for 0.5 h. To this solution was added a solution of 12 (361 mg,
1.35 mmol) in ethanol (0.68 mL). The solution was refluxed 6 h, then
diluted with EtOAc, filtered and concentrated, the residue was purified
on silica gel (Hexane/EtOAc, 10:1) to afford the product (178 mg, 94%)
as a pale-yellow oil. IR (KBr, cmÀ1) νmax: 3000, 2923, 2852, 1613, 1512,
1246, 1099, 1038, 732. 1H NMR (400 MHz, CDCl3) δ 7.25 (m, 2H),
6.86 (m, 2H), 6.28 (d, J = 11.8 Hz, 1H), 6.24 (d, J = 11.8 Hz, 1H),
5.74À5.81 (m, 2H), 4.43 (s, 2H), 3.80 (s, 3H), 3.50 (t, J = 6.7 Hz, 2H),
2.75 (br s, 2H), 2.39 (s, 3H), 2.04 (s, 3H), 1.92À2.00 (m, 2H),
1.74À1.81 (m, 4H), 1.19À1.34 (m, 24H), 0.86 (t, J = 6.8 Hz, 6H).
13C NMR (100 MHz, CDCl3) δ 159.1, 156.4, 153.3, 134.7, 134.4, 131.0,
129.3, 129.2, 129.1, 129.1, 128.8, 125.9, 125.4, 113.9, 113.7, 72.3, 70.1,
55.3, 32.6, 31.9, 31.9, 29.4, 29.4, 29.4, 29.4, 29.3, 29.2, 29.2, 29.2, 28.9,
28.8, 28.7, 23.1, 22.7, 22.7, 17.5, 14.1, 14.1. HRMS m/z calcd for
C38H60NO2 [M + H]+ = 562.4624, found 562.4621.
3-(3,5-Di((Z)-dec-1-enyl)-4,6-dimethylpyridin-2-yl)pro-
pan-1-ol (14). To a solution of 13 (178 mg, 0.32 mmol) in 7 mL of
EtOH was added 1N HCl (3.5 mL). Then the mixture was refluxed for
3 h. After cooled down, the mixture was concentrated to remove EtOH.
The water layer was extracted with CH2Cl2 (3 Â 30 mL) and the
combined organic layers were washed with brine, dried over anhydrous
Na2SO4, filtered and concentrated. The residue was purified on silica gel
(DCM/MeOH, 20:1) to give 121 mg of pale-yellow oil in 80% yield as
the hydrochloride salt. IR (KBr, cmÀ1) νmax: 3235, 2954, 2923, 2853,
1613, 1512, 1245, 1094, 1038, 722. 1H NMR (400 MHz, CDCl3) δ 6.26
(d, J = 11.5 Hz, 1H), 6.23 (d, J = 11.5 Hz, 1H), 5.76À5.84 (m, 2H), 3.71
(t, J = 5.5 Hz, 2H), 2.92 (br s, 2H), 2.38 (s, 3H), 2.06 (s, 3H), 1.89À1.94
(m, 2H), 1.73À1.80 (m, 4H), 1.19À1.32 (m, 24H), 0.86 (t, J = 6.8 Hz,
6H). 13C NMR (100 MHz, CDCl3) δ 155.6, 152.7, 144.5, 135.0, 134.9,
129.6, 129.2, 125.3, 125.2, 63.2, 33.7, 31.7, 31.7, 30.2, 29.4, 29.4, 29.4,
29.3, 29.2, 29.2, 28.9, 28.9, 28.78, 28.76, 22.6, 22.6, 22.6, 17.6, 14.1, 14.1.
HRMS m/z calcd for C30H52NO [M + H]+ = 442.4049, found 442.4035.
Anibamine (1). Methanesulfonyl chloride (53 mg, 0.46 mmol) was
added to an ice-cooled solution of 14 (110 mg, 0.23 mmol) and
triethylamine (70 mg, 0.69 mmol) in 6 mL CH2Cl2. The resulting
mixture was allowed to warm to r.t. over 1 h. The mixture was diluted
with CH2Cl2 and washed with 1N HCl twice, dried over Na2SO4,
filtered and concentrated. The residue was purified on silica gel (DCM/
MeOH, 10:1) to afford the product (75 mg, 71%) as a pale-yellow oil. IR
(KBr, cmÀ1) νmax: 3382, 2955, 2923, 2853, 1605, 1466, 728. 1H NMR
(400 MHz, CD3Cl3) δ 6.23 (d, J = 11.2 Hz, 2H), 6.06 (dt, J = 7.3 and
11.3 Hz, 1H), 6.03 (dt, J = 7.4 and 11.3 Hz, 1H), 5.38 (br, 1H), 5.09 (br,
1H), 3.37 (m, 2H), 2.83 (s, 3H), 2.62 (m, 2H), 2.28 (s, 3H), 1.79À1.84
(m, 4H), 1.22À1.39 (m, 24H), 0.86 (t, J = 6.8 Hz, 6H); 13C NMR (100
MHz, CD3Cl3): δ 154.6, 154.3, 148.8, 138.9, 138.8, 135.2, 131.3, 122.0,
121.0, 58.9, 32.6, 31.8, 31.8, 29.43, 29.40, 29.40, 29.33, 29.28, 29.2, 29.2,
29.2, 28.8, 28.6, 22.6, 22.6, 20.9, 18.8, 18.7, 14.1, 14.1. MS (ESI) m/z
424.6 (M+). (lit.10) HRMS m/z calcd for C30H50N [M]+ = 424.3943,
found 424.3926.
2-(3-(4-Methoxybenzyloxy)propyl)-3,5-di((E)-dec-1-enyl)-
4,6-dimethylpyridine (16). Pd(OAc)2 (6 mg, 0.03 mmol), PPh3 (19
mg, 0.07 mmol), and 11 (88 mg, 0.2 mmol) were stirred in toluene
(0.8 mL) and aqueous Na2CO3 (0.4 mL, 2M), under a nitrogen
atmosphere for 0.5 h. To this solution was added a solution of 15
(147 mg, 0.8 mmol) in ethanol (0.4 mL). The solution was refluxed for
6 h, then diluted with EtOAc, filtered and concentrated, the residue was
purified on silica gel (Hexane/EtOAc, 10:1) to afford the product (97 mg,
87%) as a pale yellow oil. IR (KBr, cmÀ1) νmax: 2954, 2922, 2852, 1613,
1512, 1246, 1098, 1038, 971. 1H NMR (400 MHz, CDCl3) δ 7.25 (m,
2H), 6.86 (m, 2H), 6.29 (d, J = 15.9 Hz, 1H), 6.26 (d, J = 16.0 Hz, 1H),
5.56À5.67 (m, 2H), 4.43 (s, 2H), 3.79 (s, 3H), 3.50 (t, J = 6.6 Hz, 2H),
2.79À2.84 (m, 2H), 2.45 (s, 3H), 2.18À2.26 (m, 4H), 2.18 (s, 3H),
1.93À2.00 (m, 2H), 1.42À1.50 (m, 4H), 1.28À1.38 (m, 20H), 0.88 (t,
J = 6.5 Hz, 6H). 13C NMR (100 MHz, CDCl3) δ 159.1, 156.0, 152.9,
143.1, 137.0, 137.0, 131.0, 130.7, 130.6, 129.1, 129.1, 126.2, 125.8, 113.7,
113.7, 72.3, 70.0, 55.3, 33.4, 33.3, 32.6, 31.9, 29.6, 29.49, 29.47, 29.4,
29.4, 29.31, 29.31, 29.30, 29.30, 29.2, 23.7, 22.7, 22.7, 18.1, 14.1, 14.1.
HRMS m/z calcd for C38H60NO2 [M + H]+ = 562.4624, found
562.4589.
3-(4,6-Dimethyl-3,5-di((E)-prop-1-enyl)pyridin-2-yl)prop-
an-1-ol (17). The same procedure described for 14 was used and the
residue was purified to give 75 mg pale-yellow oil in 91% yield as the
hydrochloride salt. IR (KBr, cmÀ1) νmax: 3242, 2922, 2852, 1552, 1454,
1245, 1059, 970. 1H NMR (400 MHz, CDCl3) δ 6.27 (d, J = 16.1 Hz,
1H), 6.24 (d, J = 16.1 Hz, 1H), 5.56À5.68 (m, 2H), 3.70 (t, J = 5.4 Hz,
2H), 2.96À2.99 (m, 2H), 2.44 (s, 3H), 2.20À2.26 (m, 4H), 2.19 (s, 3H),
1.88À1.94 (m, 2H), 1.44À1.51 (m, 4H), 1.24À1.38 (m, 20H), 0.89 (t,
qJ = 6.6 Hz, 6H). 13C NMR (100 MHz, CDCl3) δ 155.2, 152.3, 144.0,
137.49, 137.46, 131.0, 131.0, 125.7, 125.6, 62.8, 33.6, 33.4, 33.3, 31.9,
31.9, 30.6, 29.4, 29.4, 29.3, 29.3, 29.3, 29.23, 29.23, 29.21, 23.1, 22.7,
22.7, 18.1, 14.1, 14.1. HRMS m/z calcd for C30H52NO [M + H]+ =
442.4049, found 442.4019.
(11E,22E) Isomer of Anibamine (2). The same procedure
described for 1 was used and the product was obtained as a pale-yellow
oil, yield: 51 mg (71%). IR (KBr, cmÀ1) νmax: 3384, 2955, 2923, 2853,
1602, 1466, 976. 1H NMR (400 MHz, CD3Cl3) δ 6.26 (d, J = 16.2 Hz,
1H), 6.23 (d, J = 16.2 Hz, 1H), 5.98 (dt, J = 6.8 and 16.2 Hz, 1H), 5.82
(dt, J = 6.8 and 16.2 Hz, 1H), 5.18 (t, J = 7.6 Hz, 2H), 3.52 (t, J = 7.8 Hz,
2H), 2.85 (s, 3H), 2.53À2.61 (m, 2H), 2.37 (s, 3H), 2.24À2.31 (m, 4H),
1.45À1.50 (m, 4H), 1.24À1.32 (m, 20H), 0.89 (t, J = 6.6 Hz, 6H); 13C
NMR (100 MHz, CD3Cl3): δ 153.3, 153.1, 148.1, 142.1, 141.9, 136.7,
132.2, 122.4, 121.9, 58.8, 33.4, 33.23, 33.16, 31.9, 31.9, 29.38, 29.37,
29.27, 29.27, 29.25, 29.20, 28.84, 28.80, 22.7, 22.7, 21.2, 19.2, 19.0, 14.1,
14.1. MS (ESI) m/z 424.2 (M+). (lit.10) HRMS m/z: calcd for C30H50N
[M]+ = 424.3943, found 424.3930.
2-(3-(4-Methoxybenzyloxy)propyl)-5-bromo-3-((E)-dec-1-
enyl)-4,6-dimethylpyridine (18) and 2-(3-(4-Methoxybenzyloxy)-
propyl)-3-bromo-5-((E)-dec-1-enyl)-4,6-dimethylpyridine(19).
Pd(OAc)2 (11 mg, 0.05 mmol), PPh3 (37 mg, 0.14 mmol), and 11 (348
mg, 0.79 mmol) were stirred in toluene (1.6 mL) and aqueous Na2CO3
(0.79 mL, 2M), under a nitrogen atmosphere for 0.5 h. To this solution
was added a solution of (E)-dec-1-enylboronic acid (174 mg, 0.95
mmol) in ethanol (0.79 mL). The solution was then refluxed for 5 h,
(E)-Dec-1-enylboronic acid (15). A solution of 1-decyne (690 mg,
5 mmol) in anhydrous CH2Cl2 was cooled to 0 °C, BHBr2 Me2S
3
(1 M in CH2Cl2, 5 mL) was slowly added. After 4 h at r.t., the solution
was carefully transferred into a cooled solution of 10% aqueous NaOH
(10 mL) and the mixture was stirred at 0 °C for 15 min. Saturated aqueous
7950
dx.doi.org/10.1021/jo2013669 |J. Org. Chem. 2011, 76, 7945–7952

The Journal of Organic Chemistry
ARTICLE
diluted with EtOAc, filtered and concentrated, the residue was purified
on silica gel (Hexane/EtOAc, 8:1) to afford a mixture (345 mg, 87%)
as a pale-yellow oil. 1H NMR indicated 1:1 (3E/5E) ratio. The isomers
were separated on preparative TLC plates with Hexane/EtOAc (4:1,
v/v) as eluent after twice development give 18 as the top band a pale-
yellow oil (68 mg) and 19 as the lower band a pale-yellow oil (70 mg).
Compound 18. IR (KBr, cmÀ1) νmax: 2953, 2923, 2852, 1512,
1246, 1100, 1038, 974, 820. 1H NMR (400 MHz, CDCl3) δ 7.23 (m,
2H), 6.86 (m, 2H), 6.28 (d, J = 16.1 Hz, 1H), 5.61 (dt, J = 6.9 and 16.1
Hz, 1H), 4.42 (s, 2H), 3.80 (s, 3H), 3.48 (t, J = 6.6 Hz, 2H), 2.77À2.81
(m, 2H), 2.62 (s, 3H), 2.36 (s, 3H), 2.18À2.24 (m, 2H), 1.92À1.99 (m,
2H), 1.42À1.50 (m, 2H), 1.24À1.36 (m, 10H), 0.89 (t, J = 6.7 Hz, 3H).
13C NMR (100 MHz, CDCl3) δ 159.1, 156.8, 154.2, 144.9, 138.2, 132.1,
130.8, 129.1, 129.1, 125.3, 122.2, 113.7, 113.7, 72.4, 69.8, 55.2, 33.2, 32.3,
31.9, 29.5, 29.32, 29.30, 29.2, 29.2, 25.9, 22.7, 21.3, 14.1. HRMS m/z
calcd for C28H41BrNO2 [M + H]+ = 502.2321, found 502.2302.
Compound 19. IR (KBr, cmÀ1) νmax: 2954, 2924, 2853, 1512,
1248, 1101, 1037, 974, 820. 1H NMR (400 MHz, CDCl3) δ 7.27 (m,
2H), 6.87 (m, 2H), 6.26 (d, J = 16.1 Hz, 1H), 5.64 (dt, J = 6.9 and 16.1
Hz, 1H), 4.46 (s, 2H), 3.80 (s, 3H), 3.55 (t, J = 6.6 Hz, 2H), 2.98À3.02
(m, 2H), 2.41 (s, 3H), 2.37 (s, 3H), 2.22À2.27 (m, 2H), 2.01À2.08 (m,
2H), 1.44À1.52 (m, 2H), 1.24À1.38 (m, 10H), 0.89 (t, J = 6.6 Hz, 3H).
13C NMR (100 MHz, CDCl3) δ 159.1, 156.7, 153.7, 144.8, 138.1, 132.3,
130.9, 129.2, 129.2, 125.8, 122.0, 113.7, 113.7, 72.4, 69.7, 55.3, 35.0, 32.2,
31.9, 29.4, 29.3, 29.2, 29.2, 28.6, 23.4, 22.7, 21.3, 14.1. HRMS m/z calcd
for C28H41BrNO2 [M + H]+ = 502.2321, found 502.2295.
2-(3-(4-Methoxybenzyloxy)propyl)-3-((E)-dec-1-enyl)-5-
((Z)-dec-1-enyl)-4,6-dimethylpyridine (20). Pd(OAc)2 (4 mg,
0.02 mmol), PPh3 (13 mg, 0.05 mmol), and 18 (65 mg, 0.13 mmol) were
stirred in toluene (0.38 mL) and aqueous Na2CO3 (0.19 mL, 2M),
under a nitrogen atmosphere for 0.5 h. To this solution was added a
solution of diisopropyl (Z)-1-decenylboronate (104 mg, 0.39 mmol) in
ethanol (0.19 mL). The solution was refluxed 4 h, then diluted with
EtOAc, filtered and concentrated, the residue was purified on silica gel
(Hexane/EtOAc, 8:1) to afford the product (68 mg, 93%) as a pale-
yellow oil. IR (KBr, cmÀ1) νmax: 2954, 2922, 2852, 1512, 1456, 1246,
1100, 1038, 971, 721. 1H NMR (400 MHz, CDCl3) δ 7.26 (m, 2H), 6.86
(m, 2H), 6.30 (d, J = 16.1 Hz, 1H), 6.22 (d, J = 11.2 Hz, 1H), 5.77 (dt, J =
7.2 and 11.2 Hz, 1H), 5.62 (dt, J = 6.9 and 16.1 Hz, 1H), 4.43 (s, 2H),
3.80 (s, 3H), 3.51 (t, J = 6.7 Hz, 2H), 2.83 (t, J = 7.8 Hz, 2H), 2.37 (s,
3H), 2.20À2.24 (m, 2H), 2.11 (s, 3H), 1.95À2.02 (m, 2H), 1.76À1.82
(m, 2H), 1.43À1.50 (m, 2H), 1.20À1.31 (m, 22H), 0.88 (t, J = 6.7 Hz,
3H), 0.86 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 159.0,
156.4, 152.9, 143.3, 137.0, 134.4, 130.9, 130.2, 129.4, 129.1, 129.1, 125.9,
125.7, 113.7, 113.7, 72.3, 70.0, 55.2, 33.4, 32.6, 31.9, 31.8, 30.9, 29.6,
29.5, 29.4, 29.34, 29.30, 29.26, 29.2, 28.9, 28.7, 23.2, 22.7, 22.6, 17.7,
14.11, 14.09. HRMS m/z calcd for C38H60NO2 [M + H]+ = 562.4624,
found 562.4598.
(11Z,22E) Isomer of Anibamine (3). The same procedure
described for 1 was used. The product was obtained as a yellow oil,
yield: 44 mg (94%). IR (KBr, cmÀ1) νmax: 3386, 2955, 2923, 2853, 1604,
1466, 1340, 978, 723. 1H NMR (400 MHz, CDCl3) δ 6.27 (d, J = 16.2
Hz, 1H), 6.21 (d, J = 11.4 Hz, 1H), 6.05 (dt, J = 7.3 and 11.4 Hz, 1H),
6.02 (dt, J = 6.9 and 16.2 Hz, 1H), 5.28 (br, 1H), 4.99 (br, 1H), 3.54 (m,
2H), 2.76 (s, 3H), 2.54À2.63 (m, 2H), 2.33 (s, 3H), 2.25À2.31 (m, 2H),
1.77À1.83 (m, 2H), 1.46À1.53 (m, 2H), 1.22À1.35 (m, 22H), 0.89 (t,
J = 6.7 Hz, 3H), 0.86 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ
153.8, 153.4, 148.0, 142.0, 138.8, 135.2, 132.2, 122.1, 121.8, 58.6, 33.5,
33.2, 31.9, 31.8, 29.4, 29.4, 29.25, 29.25, 29.22, 29.17, 29.10, 28.8, 28.6,
22.7, 22.6, 21.2, 18.7, 18.6, 14.11, 14.09. MS (ESI) m/z 424.3 (M+).
HRMS m/z calcd for C30H50N [M]+ = 424.3943, found 424.3932.
2-(3-(4-Methoxybenzyloxy)propyl)-5-((E)-dec-1-enyl)-3-
((Z)-dec-1-enyl)-4,6-dimethylpyridine (22). The same proce-
dure described for 20 was used. The product was obtained as a pale-
yellow oil, yield: 70 mg (96%). IR (KBr, cmÀ1) νmax: 2954, 2922, 2852,
1
1612, 1512, 1455, 1246, 1100, 1038, 971, 722. H NMR (400 MHz,
CDCl3) δ 7.25 (m, 2H), 6.86 (m, 2H), 6.27 (d, J = 16.1 Hz, 1H), 6.26 (d,
J = 11.2 Hz, 1H), 5.77 (dt, J = 7.2 and 11.2 Hz, 1H), 5.65 (dt, J = 6.9 and
16.1 Hz, 1H), 4.42 (s, 2H), 3.80 (s, 3H), 3.49 (t, J = 6.7 Hz, 2H), 2.74 (br
s, 2H), 2.47 (s, 3H), 2.21À2.26 (m, 2H), 2.12 (s, 3H), 1.91À1.98 (m,
2H), 1.75À1.81 (m, 2H), 1.45À1.52 (m, 2H), 1.19À1.39 (m, 22H),
0.89 (t, J = 6.6 Hz, 3H), 0.86 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz,
CDCl3) δ 159.0, 155.9, 153.3, 143.1, 136.9, 134.6, 131.0, 130.4, 129.1,
129.1, 129.1, 126.2, 125.5, 113.7, 113.7, 72.2, 70.1, 55.3, 33.4, 32.6, 31.88,
31.85, 29.45, 29.41, 29.35, 29.34, 29.30, 29.2, 29.2, 29.1, 28.9, 28.76,
23.75, 22.7, 22.6, 17.7, 14.09, 14.08. HRMS m/z calcd for C38H60NO2
[M + H]+ = 562.4624, found 562.4588.
3-(5-((E)-Dec-1-enyl)-3-((Z)-dec-1-enyl)-4,6-dimethylpyri-
din-2-yl)propan-1-ol (23). The same procedure described for 14
was used and the residue was purified to give 53 mg of pale-yellow oil in
91% yield as the hydrochloride salt. IR (KBr, cmÀ1) νmax: 3374, 2954,
1
2923, 2853, 1643, 1455, 1300, 1062, 973, 722. H NMR (400 MHz,
CDCl3) δ 6.22 (m, 2H), 5.94 (dt, J = 7.3 and 11.2 Hz, 1H), 5.76 (dt, J =
6.9 and 16.2 Hz, 1H), 3.72 (t, J = 5.5 Hz, 2H), 3.06 (t, J = 6.6 Hz, 2H),
2.65 (s, 3H), 2.24À2.30 (m, 2H), 2.24 (s, 3H), 1.88À1.94 (m, 2H),
1.74À1.80 (m, 2H), 1.46À1.53 (m, 2H), 1.21À1.35 (m, 22H), 0.89 (t,
J = 6.7 Hz, 3H), 0.87 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ
154.6, 151.8, 146.3, 138.4, 135.8, 131.6, 130.2, 124.8, 124.4, 62.5, 33.4,
32.4, 31.85, 31.81, 30.5, 29.40, 29.36, 29.29, 29.27, 29.18, 29.17, 29.17,
29.17, 28.83, 28.80, 22.64, 22.61, 18.0, 14.06, 14.05. HRMS m/z calcd for
C30H52NO [M + H]+ = 442.4049, found 442.4019.
(11E,22Z) Isomer of Anibamine (4). The same procedure
described for 1 was used. The product was obtained as a yellow oil,
yield: 46 mg (91%). IR (KBr, cmÀ1) νmax: 3388, 2955, 2922, 2853, 1604,
1466, 978, 722. 1H NMR (400 MHz, CDCl3) δ 6.23 (d, J = 16.2 Hz,
1H), 6.20 (d, J = 11.3 Hz, 1H), 6.05 (dt, J = 7.3 and 11.3 Hz, 1H), 6.02
(dt, J = 6.9 and 16.2 Hz, 1H), 5.26 (t, J = 7.3 Hz, 2H), 3.34 (t, J = 7.6 Hz,
2H), 2.92 (s, 3H), 2.54À2.62 (m, 2H), 2.31 (s, 3H), 2.26À2.31 (m, 2H),
1.79À1.84 (m, 2H), 1.47À1.54 (m, 2H), 1.22À1.38 (m, 22H), 0.89 (t,
J = 6.6 Hz, 3H), 0.87 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ
154.0, 153.6, 148.8, 142.2, 138.9, 136.6, 131.2, 122.2, 121.0, 59.0, 33.2,
32.6, 31.84, 31.81, 29.4, 29.4, 29.4, 29.3, 29.23, 29.20, 29.16, 28.75, 28.74,
22.64, 22.61, 20.9, 19.2, 18.9, 14.09, 14.06. MS (ESI) m/z 424.3 (M+).
HRMS m/z calcd for C30H50N [M]+ = 424.3943, found 424.3924.
Molecular Modeling Procedure. The structures of anibamine
and its three isomers were built using Sybyl 8.1 with, unless specified,
default parameters, followed by energy minimization (Tripos forcefield,
3-(3-((E)-Dec-1-enyl)-5-((Z)-dec-1-enyl)-4,6-dimethylpyri-
din-2-yl)propan-1-ol (21). The same procedure described for 14
was used and the residue was purified to give 50 mg of pale-yellow oil in
90% yield as the hydrochloride salt. IR (KBr, cmÀ1) νmax: 3267, 2954,
1
2922, 2853, 1553, 1455, 1246, 1041, 970, 722. H NMR (400 MHz,
CDCl3) δ 6.28 (d, J = 16.1 Hz, 1H), 6.21 (d, J = 11.2 Hz, 1H), 5.79 (dt,
J = 7.2 and 11.2 Hz, 1H), 5.62 (dt, J = 6.8 and 16.1 Hz, 1H), 3.71 (t, J =
5.3 Hz, 2H), 3.00 (t, J = 6.0 Hz, 2H), 2.37 (s, 3H), 2.21À2.27 (m, 2H),
2.13 (s, 3H), 1.92À1.96 (m, 2H), 1.75À1.80 (m, 2H), 1.45À1.50 (m,
2H), 1.20À1.33 (m, 22H), 0.89 (t, J = 6.4 Hz, 3H), 0.86 (t, J = 7.0 Hz,
3H). 13C NMR (100 MHz, CDCl3) δ 155.5, 152.3, 144.3, 137.4, 134.9,
130.6, 129.7, 125.5, 125.4, 62.9, 33.6, 33.3, 31.9, 31.8, 30.6, 29.44, 29.38,
29.31, 29.28, 29.25, 29.23, 29.21, 29.21, 28.9, 28.7, 22.7, 22.6, 17.8, 14.10,
14.09. HRMS m/z calcd for C30H52NO [M + H]+ = 442.4049, found
442.4024.
Gasteiger-H€uckel charges) with default termination at 0.05 kcal molÀ1 ÅÀ1
.
The energy minimized structures were then solvated in a water box
(compound 1, periodic box size, 79,170.4 Å3, 42.76 Å each side, number
of waters, 3474; compound 2, periodic box size, 119,018.2 Å3, 49.19 Å each
side, number of waters, 5288; compound 3, periodic box size, 104,737.0 Å3,
7951
dx.doi.org/10.1021/jo2013669 |J. Org. Chem. 2011, 76, 7945–7952

The Journal of Organic Chemistry
ARTICLE
46.99 Å each side, number of waters, 4609; compound 4, periodic box size,
95,426.2 Å3, 45.33 Å each side, number of waters, 4156). The isomers in
these water boxes were again energy minimized (Tripos forcefield, Gastei-
ger-H€uckel charges, constant dielectric =80, termination 0.05 kcal molÀ1
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Calcium Assay Protocol. MOLT-4/CCR5 cells were plated in
black 96-well plates with transparent bottom (Greinier Bio-one) at
100 000 cells per well in 50:1 HBSS:HEPES assay buffer. They were
incubated for 1 h at 37 °C and 5% CO2 with control buffer or varying
concentration of compound for a total volume of 130 μL per well. Cells
were then incubated with 50 μL of Fluo-4 a.m. loading buffer (40 μL
2 μM Fluo-4 dye, 100 μL 2.5 mM probenacid, in 5 mL assay buffer) for an
additional hour. Then 20 μL 200 nM RANTES solution in assay buffer or
assay buffer alone were added to the wells right before changes in Ca2+
concentration were monitored by RFU for 90 s using a microplate reader
(FlexStation3, Molecular Devices). Peak values were obtained using
SoftMaxPro software (Molecular Devices) and nonlinear regression
curves were generated using Prism (GraphPad) to calculate IC50 values.
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Supporting Information. Purity test results and copies
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’ AUTHOR INFORMATION
(12) Woon, P. B.; Jung, M. K.; Young, S. K.; Cheol, H. Y.; Shin, J. K.;
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Corresponding Author
yzhang2@vcu.edu
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We are grateful for the funding support from US Army
Prostate Cancer Research Program PC073739, and NIH/NIAID
AI074461. The content of this report is solely the responsibility
of the authors and does not necessarily represent the official
views of the National Institute of Allergy and Infectious Diseases,
the National Institutes of Health, nor the US Army Prostate
Cancer Research Program. We thank the NIH AIDS Research
and Reference Reagent Program for providing the MOLT-4/
CCR5 cell line.
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