Design, synthesis and evaluation of retinoids with novel bulky hydrophobic partial structures

Article abstract of DOI:10.1016/j.bmc.2013.04.053

Many synthetic retinoids contain an aromatic structure with a bulky hydrophobic fragment. In order to obtain retinoids with therapeutic potential that do not bind to or activate retinoic acid X receptors (RXRs), we focused on the introduction of novel hyd

Full text of DOI:10.1016/j.bmc.2013.04.053

Accepted Manuscript
Design, Synthesis and Evaluation of Retinoids with Novel Bulky Hydrophobic
Partial Structures
Yohei Amano, Masayuki Noguchi, Madoka Nakagomi, Hideaki Muratake,
Hiroshi Fukasawa, Koichi Shudo
PII:
S0968-0896(13)00379-9
DOI:
http://dx.doi.org/10.1016/j.bmc.2013.04.053
BMC 10793
Reference:
To appear in:
Bioorganic & Medicinal Chemistry
Received Date:
Revised Date:
Accepted Date:
30 March 2013
20 April 2013
22 April 2013
Please cite this article as: Amano, Y., Noguchi, M., Nakagomi, M., Muratake, H., Fukasawa, H., Shudo, K., Design,
Synthesis and Evaluation of Retinoids with Novel Bulky Hydrophobic Partial Structures, Bioorganic & Medicinal
Chemistry (2013), doi: http://dx.doi.org/10.1016/j.bmc.2013.04.053
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Design, Synthesis and Evaluation of Retinoids with Novel Bulky Hydrophobic Partial
Structures
Yohei Amano*, Masayuki Noguchi, Madoka Nakagomi, Hideaki Muratake, Hiroshi Fukasawa,
Koichi Shudo
Research Foundation Itsuu Laboratory, 2-28-10 Tamagawa, Setagaya-ku, Tokyo 158-0094, Japan
*Corresponding author. Tel.: +81 3 3700 5432; fax: +81 3 3700 5431.
E-mail address: yamano@itsuu.or.jp (Y. Amano).

Abstract
Many synthetic retinoids contain an aromatic structure with a bulky hydrophobic fragment. In
order to obtain retinoids with therapeutic potential that do not bind to or activate retinoic acid X
receptors (RXRs), we focused on the introduction of novel hydrophobic moieties, i.e.,
metacyclophane, phenalene and benzoheptalene derivatives. The designed compounds were
synthesized and their agonistic activities towards RARs and RXRs were evaluated. Most of the
active compounds showed selectivity for RAR and RAR over RAR , and higher RAR
transactivating activity seemed to correlate with higher cell differentiation-inducing activity towards
promyelocytic leukemia cell line HL-60. These compounds showed no agonistic activity towards
RXRs.
1. Introduction
All-trans-retinoic acid (ATRA) is an active metabolite of vitamin A, and its chemistry and biology
have been intensively investigated1. ATRA and related compounds with similar activities (generally
called retinoids) regulate various critical biological functions, including cell proliferation and
morphogenesis, as well as differentiation of embryonic stem cells and committed cells such as blood,
dermal, immunological and neuronal cells, by activating retinoic acid receptors (RARs) 2-7
.
Figure 1
Many synthetic agonists and antagonists of ATRA’s activities have been reported8-10. These
compounds are ligands of nuclear receptors, RARs and/or RXRs, each of which has three subtypes,
i.e., RAR , RAR , RAR and RXR , RXR , RXR , respectively11-21. RXRs dimerize with many other
nuclear receptors, so for therapeutic purposes (e.g., to treat immunological and neurodegenerative
disorders such as Alzheimer’s disease), it is important to find compounds that bind selectively to
RARs, and not to RXRs22-25. Among existing compounds, tamibarotene (Am80) is a very potent,
RAR-selective, non-irritative, and synthetically accessible agent26. Therefore, it is a significant
challenge to develop new compounds superior to Am80, even though it has been known for a long
time.
Among aromatic retinoids, Am8027, Am555S (amsilarotene)28 and their derivatives29 contain an
amide group which links two aromatic rings, one of which bears a bulky hydrophobic fragment.
Generally, such compounds are selective for RAR and RAR , while they only slightly activate RAR ,
and do not bind to RXRs, which is a therapeutically desirable profile30-33. Thus, in order to find
structurally new receptor-selective retinoids as candidates for further clinical application, we focused
on the bulky hydrophobic fragment of synthetic retinoids and designed a series of compounds with
novel hydrophobic moieties, i.e., metacyclophane, phenalene and benzoheptalene derivatives. The

activities, including cell differentiation-inducing activity, of the synthesized compounds were
evaluated.
2. Chemistry
As described above, structure-activity studies suggested that we should focus on the bulky
hydrophobic fragment of synthetic retinoids.27-33 Thus, we designed and synthesized a series of
metacyclophane, phenalene and benzoheptalene derivatives.
2.1. Metacyclophane derivatives
Among [n]metacyclophane derivatives, [10]metacyclophane has been prepared from
1,3-dichlorobenzene by Tamao34, though yields were poor. Smaller metacyclophanes are
synthetically inaccessible, so we focused on [10]metacyclophane derivatives. Nitration of
[10]metacyclophane gave 12-nitro (15%) and 12,14-dinitro derivatives (61%), but not the 13-nitro
derivative. 13-Substituted derivatives (1, 2), which structurally correspond to Am80, were obtained
through multistep reactions from the 12,14-dinitro or 12-nitro compound. The 12,14-dinitro
compound was first reduced to diamine, then the 13-nitro group was introduced, and the two amino
groups were reductively removed to afford the 13-nitro derivative, which was reduced to
13-amino[10]metacyclophane. This was derivatized to the benzoic acid derivative (1). The 12-nitro
compound was converted via multistep processes to the 13-carboxy compound and then reacted with
methyl 4-aminobenzoate followed by hydrolysis to afford compound (2).
Figure 2
2.2. Phenalene derivatives
Although the [10]metacyclophane derivatives showed significant biological activity, further
derivatization proved impractical. Instead, we designed a series of compounds that may be regarded
as mimics of the macrocyclic ring, i.e., 5,6,6a,7,8,9-hexahydro-4H-phenalene derivatives.
Figure 3
Nitration of the hexahydro-4H-phenalene, synthesized from 1-tetralone35, did not proceed at the
desired position, affording only the 1-substituted compound. However, acetylation gave a mixture of
1- and 2-acetyl derivatives. Various reaction conditions were examined, but did not increase the ratio
of the 2-derivative. The products were separated by chromatography, and oxidized with
hypobromide to the corresponding carboxylic acids (see Supplementary data). The 2-carboxylic acid
was converted to 2-amine, then reacted with several methyl terephthalic acid chlorides to afford

4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenenyl)carbamoyl-4-benzoic acid derivatives (3a-6a). The
2-carboxylic acid was also condensed with various aminobenzoic acid esters to give
4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamide]-4-benzoic acid derivatives (7a-14a).
An angular methyl-substituted hexahydrophenalene was synthesized from
3-bromophenylpropane36. Acetylation of the phenalene proceeded smoothly to afford the 2-acetyl
compound, and this was treated as above to give the desired phenalenecarbamoylbenzoic acids
(3b-6b) and phenalenecarboxamide-4-benzoic acids (7b-14b)
2.3. Benzo[ef]heptalene derivatives
The benzo[ef]heptalene skeleton was prepared from 1-benzosuberone by means of two successive
Horner-Emmons reactions and cyclization to ketone, and then the carbonyl group was removed with
Et3SiH-trifluoroacetic acid to give 5,6,7,7a,8,9,10,11-octahydro-4H-benzo[ef]heptalene (see
Supplementary data).
The acetylation proceeded smoothly to give the desired 2-acetyl derivative as the major product
with 1-acetyl heptalene as a minor product. The 2-acetyl derivative was readily converted to
carboxylic acid and then to the corresponding amine. The carbamoyl derivatives (15, 16) and
carboxamide derivatives (17-22) were prepared in the manner described above.
Figure 4
3. Biological Activity
3.1. Transcriptional activity
The functional profiles of the novel compounds were evaluated by means of reporter assay
utilizing COS-1 cells with expression vectors containing GAL4-RAR ( , , and ) and full length
RXR ( , , and ). GAL4-RARs were produced by using the CheckMate™ Mammalian Two-Hybrid
System (Progema code #E2440). They were composed of pBIND vector and each ligand-binding
domain. When retinoids interact with this domain, GAL4-RAR vector binds to the reporter plasmid,
pG5luc vector, and firefly luciferase is expressed37. The results were expressed as fold activation
with respect to the blank control value. Am80 and ATRA were used as positive controls for RARs
and HX630 was used as positive control for RXRs.
Table 1
Figure 5
3.2. Differentiation-inducing assay

Human promyelocytic leukemia cell line HL-60 was cultured in RPMI-1640 medium
supplemented with 5% FBS in a humidified atmosphere of 5% CO2 in air at 37°C. Test compounds
were added to the cells, which were seeded at about 8.0×104 cells/ml. The final DMSO
concentration was kept below 0.1%. Control cells were given only the same volume of DMSO.
Am80 and ATRA (positive controls) were assayed at the same time. The cells were incubated for 4
days and differentiated cells were evaluated by NBT reduction assay. Cells were incubated for 20
min at 37°C in RPMI-1640 medium (5%) and an equal volume of phosphate-buffered saline (PBS)
containing NBT (0.2%) and 12-O-tetradecanoylphorbol-13-acetate (TPA) as described26. The
percentage of cells differentiated to monocytes (containing blue-black formazan) was determined on
a minimum of 200 cells.
Table 2
4. Results and discussion
The metacyclophane derivatives (1, 2) showed significant agonistic activity towards RARs (about
1/10 of that of retinoic acid towards RAR and RAR without activity towards RXRs, but synthetic
difficulty meant that we could not obtain a wider range of derivatives for further evaluation.
Tricyclic phenalene and heptalene derivatives both showed similar patterns of activity to other
corresponding amides such as tamibarotene. The preferred linking position of the amide (carbamoyl
or carboxamide) benzoic acid group is meta (8-position of phenalene, and 2-position of heptalene).
Generally, carboxamide-type benzoic acid derivatives have higher activities in transactivation assay
than carbamoyl-type compounds. Introduction of fluorine as a substituent on the benzoic acid seems
to increase the activity towards RAR without affecting that towards RAR (cf. 7b vs 11b; 17 vs 19).
Introduction of a nitrogen atom in the benzoic acid moiety (nicotinic acid) resulted in higher RAR
activity (7a vs 8a; 7b vs 8b; 17 vs 18). It might be possible to utilize this finding to obtain RAR
antagonists. Thiophene carboxylic acid showed a lower activity than benzoic acid. Among the
compounds listed in Scheme, 11a, 11b, 12b and 19 are the most selective, showing high selectivity
for RAR , lower selectivity for RAR , and very low (at 1000 nM) activity towards RAR . The ratio
of activities (EC50) towards RAR and RAR is more than 100. Compounds 8a, 8b and 18 showed
potent RAR transactivation activity. In particular, 18 is a potent pan-RAR agonist. Compounds 4a
and 4b are relatively selective for RAR among these compounds. Absence of RAR activity is
preferable for clinical application, because activation of RAR is associated with skin irritation and
other unfavorable events30-33
.
All of the compounds were inactive towards RXRs at 1000 nM, and so these amide-type retinoids
can be classified as strongly RAR-specific. This is very important, because RXR dimerizes with
many other nuclear receptors, including TR, VDR, Nurr and PPAR. Although it was believed that

ATRA activates all three RARs, but not RXRs, while 9-cis-retinoic acid (9cRA) activates both RARs
and RXRs, recent work has shown that ATRA activates RXRs as well as RARs, at least under
conditions of cell culture. For example, ATRA activates RXR in CAT-reporter assay at the
concentration (EC50) of 50 nM15, and its agonistic potency for RARs is in the range of only 3 to 8
times17 or 40 times19 greater than that for RXRs. Therefore, it seems to have been wrongly
concluded that the biological activities of ATRA are mediated only by RARs14, 21, and other nuclear
receptors that may be activated by RXRs could also play a significant role37-41. Therefore, the
present RAR-specific ligands, which do not activate RXRs, could be very useful in medicinal and
biological research. It should be noted that the level of 9-cis-retinoic acid in tissues is very low, and
may not be high enough to activate endogenous RXR receptors42, 43
.
We also examined the effects of our compounds on the differentiation of promyelocytic leukemia
cell line, HL-60 cells, to mature myeloid cells, which is thought to involve RAR 44, 45. Among the
present compounds, those that activate both RAR and RAR showed high differentiating activities.
The highest cell-differentiating activity was observed with 8a and 8b. Interestingly, 19, 20 and 21
showed weaker activity than Am80, even though their agonistic activity towards RAR seems to be
equal to or higher than that of Am80. This may suggest that HL-60 differentiation is more influenced
by RAR activation than by RAR activation. This idea is supported by the absence of inhibition of
HL-60 proliferation by 19 at concentrations up to 10-6 M, even though the agonistic activity of RAR
of the compound is higher than that of Am80. However, it is important to note that RAR activation
often leads to induction of RAR , so RAR activation may be necessary as a prerequisite to the RAR
activation. It is also important that at least some of the present compounds are less cytotoxic than
ATRA or Am80.
Finally, the activity of compounds in reporter assays such as those used here may depend on many
factors, including plasmid construction, the kind of cells used, the presence of various transcriptional
cofactors, and incubation conditions, so it will be important to evaluate the biological activity of our
compounds more extensively in vivo.
5. Conclusion
Retinoids containing metacyclophane, phenalene and benzoheptalene as bulky hydrophobic
structures were synthesized and their agonistic activities towards RARs and RXRs were evaluated.
These compounds were generally selective for RAR and RAR over RAR while they showed no
agonistic activity towards RXRs. Among these compounds, low RAR -selective activity was
correlated with weak HL-60 differentiation-inducing activity, suggesting that RAR activation may
play a prominent role in the differentiation of HL-60 cells.
6. Experimental

6.1. General
Melting points were determined on a Yanagimoto micro-melting point apparatus (hot plate), and
are not corrected. 1H NMR spectra were obtained on a Varian Mercury 300 at 300 MHz in CDCl3
or in DMSO-d6. The chemical shifts are calculated on the basis of tetramethylsilane (0 ppm in
CDCl3) or (CH3)2SO (2.49 ppm in DMSO-d6). High-resolution ESI-MS (HR-ESI-MS) was
recorded on a Shimadzu LCMS-IT-TOF spectrometer. Column chromatography was conducted on
silica gel (Fuji Davison BW 200). Usual work-up refers to washing of the organic phase with water
or brine, drying over anhydrous Na2SO4, and removing the solvent(s) by evaporation under reduced
pressure.
6.2. Synthesis of metacyclophane derivatives (1 and 2).
4-[13-([10]Metacyclophanyl)carbamoyl]benzoic acid (1)
To a solution of 13-amino[10]metacyclophane (0.090 g, 0.389 mmol) in benzene (10 ml) and
pyridine (2 ml) was added terephthalic acid monomethyl ester chloride (0.116 g, 0.584 mmol). The
reaction mixture was stirred at rt for 3 h, then poured into 2 M aqueous HCl and extracted with
AcOEt. The organic phase was washed with 10% aqueous Na2CO3. Usual work-up gave a residue,
which was purified by silica gel column chromatography (AcOEt:n-hexane = 1:20) to afford methyl
4-[13-([10]metacyclophanyl)carbamoyl]benzoate (0.116 g, 76%). To a solution of the above ester
(0.094 g, 0.239 mmol) in EtOH (8 ml) was added 2 M aqueous NaOH (3 ml). The reaction mixture
was stirred at rt for 3 h, then acidified by adding 2 M aqueous HCl and extracted with CHCl3. Usual
work-up gave a residue, which was purified by recrystallization from AcOEt/n-hexane to afford 1
1
(0.080 g, 88%). 1: Colorless plates (AcOEt/n-hexane); mp 234-235°C; H NMR (DMSO-d6) :
0.86-1.00 (4H, m), 1.04-1.11 (4H, m), 1.12-1.23 (4H, m), 1.60-1.70 (4H, m), 2.61 (4H, t, J=5.7 Hz),
6.93 (1H, s), 7.44 (2H, s), 8.04 (4H, s), 10.26 (1H, s); HR-ESI-MS m/z: 378.2069 ([M-H]+, calcd for
C24H28NO3, 378.2069).
4-[13-([10]Metacyclophanyl)carboxamido]benzoic acid (2)
To a suspension of [10]metacyclophane-13-carboxylic acid (0.175 g, 0.672 mmol) in benzene (3
ml) was added SOCl2 (1 ml). The reaction mixture was refluxed for 4 h, then evaporated, and the
residue was dissolved in benzene (2 ml) and pyridine (5 ml). Methyl 4-aminobenzoate (0.106 g,
0.701 mmol) and a small amount of 4-DMAP were added to the resulting solution. The reaction
mixture was stirred at rt overnight, poured into 2 M aqueous HCl and extracted with AcOEt. The
organic phase was washed with 10% aqueous Na2CO3. Usual work-up gave a residue, which was
purified by silica gel column chromatography (AcOEt:n-hexane=1:30) to afford methyl
4-[13-([10]metacyclophanyl)carboxamido]benzoate (0.179 g, 68%). To a solution of the above ester

(0.175 g, 0.445 mmol) in EtOH (10 ml) was added 2 M aqueous NaOH (3 ml). The reaction mixture
was stirred at rt for 6 h, then acidified by adding 2 M aqueous HCl and extracted with CHCl3. Usual
work-up gave a residue, which was purified by recrystallization from AcOEt/n-hexane to afford 2
1
(0.146 g, 86%). 2: Colorless needles (AcOEt/n-hexane); mp 273-274°C; H NMR (DMSO-d6) :
0.86-1.00 (4H, m), 1.04-1.12 (4H, m), 1.13-1.23 (4H, m), 1.72 (4H, br s), 2.73 (4H, t, J=5.7 Hz),
7.42 (1H, s), 7.64 (2H, s), 7.93 (4H, s), 10.44 (1H, s); HR-ESI-MS m/z: 378.2070 ([M-H]+, calcd for
C24H28NO3, 378.2069).
6.3. Synthesis of phenalene derivatives (3a, b-14a, b)
4-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carbamoyl]benzoic acid (3a) and analogs (4a-6a)
To a solution of 5,6,6a,7,8,9-hexahydro-4H-2-phenalenylamine46 (0.260 g, 1.39 mmol) in benzene
(10 ml) and pyridine (3 ml) was added terephthalic acid monomethyl ester chloride (0.304 g, 1.53
mmol). The reaction mixture was stirred at rt for 3 h, then poured into 2 M aqueous HCl and
extracted with AcOEt. The organic phase was washed with 10% aqueous Na2CO3. Usual work-up
gave a residue, which was purified by recrystallization from CHCl3/n-hexane give methyl
4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carbamoyl]benzoate (0.460 g, 95%). To a suspension of
the above ester (0.093 g, 0.266 mmol) in EtOH (10 ml) was added 2 M aqueous NaOH (3 ml). The
reaction mixture was stirred at rt for 3 h, then acidified by adding 2 M aqueous HCl and extracted
with CHCl3. Usual work-up gave a residue, which was purified by recrystallization from
AcOEt/n-hexane to afford 3a (0.080 g, 90%). 3a: Colorless prisms (AcOEt/n-hexane); mp
1
283-284°C; H NMR (DMSO-d6) : 1.21-1.30 (2H, m), 1.25-1.78 (2H, m), 1.81-1.94 (4H, m),
2.43-2.47 (1H, m), 2.73-2.76 (4H, m), 7.30 (2H, s), 8.01 (2H, d, J=8.6 Hz), 8.05 (2H, d, J=8.6 Hz),
10.15 (1H, s); HR-ESI-MS m/z: 334.1430 ([M-H]+, calcd for C21H20NO3, 334.1443).
6-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carbamoyl]nicotinic acid (4a): 83% yield. Pale
yellow needles (AcOEt/n-hexane); mp 252-253°C; 1H NMR (CDCl3) : 1.26-1.40 (2H, m), 1.72-1.86
(2H, m), 1.88-2.00 (4H, m), 2.51-2.61 (1H, m), 2.82-2.87 (4H, m), 7.36 (2H, s), 8.42 (1H, d, J=8.1
Hz), 8.58 (1H, dd, J=8.1, 2.1 Hz), 9.26 (1H, d, J=2.1 Hz), 9.88 (1H, s); HR-ESI-MS m/z: 335.1380
([M-H]+, calcd for C20H19N2O3, 335.1396).
5-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carbamoyl]pyridine-2-carboxylic acid (5a): 89%
yield. Pale yellow needles (AcOEt/n-hexane); mp 239-240°C; 1H NMR (DMSO-d6) : 1.14-1.28 (2H,
m), 1.63-1.76 (2H, m), 1.78-1.83 (2H, m), 1.84-1.92 (2H, m), 2.40-2.42 (1H, m), 2.71-2.74 (4H, m),
7.27 (2H, s), 8.13 (1H, d, J=8.1 Hz), 8.40 (1H, dd, J=8.1, 2.1 Hz), 9.13 (1H, d, J=2.1 Hz), 10.32 (1H,
s); HR-ESI-MS m/z: 335.1372 ([M-H]+, calcd for C20H19N2O3, 335.1396).
5-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carbamoyl]thiophene-2-carboxylic acid (6a): 65%
yield. Pale yellow powder (AcOEt/n-hexane); mp 281-283°C; 1H NMR (DMSO-d6) : 1.18-1.27 (2H,

m), 1.66-1.76 (2H, m), 1.77-1.92 (4H, m), 2.44-2.45 (1H, m), 2.71-2.73 (4H, m), 7.22 (2H, s), 7.26
(1H, d, J=4.2 Hz), 7.95 (1H, d, J=4.2 Hz), 10.17 (1H, s); HR-ESI-MS m/z: 340.1004 ([M-H]+, calcd
for C19H18NO3S, 340.1007).
4-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carboxamido]benzoic acid (7a) and analogs
(8a-14a)
To a suspension of 5,6,6a,7,8,9-hexahydro-4H-phenalene-2-carboxylic acid46 (0.338 g, 1.56
mmol) in benzene (7.5 ml) was added SOCl2 (2.5 ml). The reaction mixture was refluxed for 4 h,
then evaporated, and the residue was dissolved in benzene (3 ml) and pyridine (10 ml). Methyl
4-aminobenzoate (0.259 g, 1.71 mmol) and 4-DMAP (0.020 g, 0.164 mmol) were added to the
resulting solution. The reaction mixture was stirred at rt for 15 h, then poured into 2 M aqueous HCl
and extracted with AcOEt. The organic phase was washed with 10% aqueous Na2CO3. Usual
work-up gave
a
residue, which was purified by silica gel column chromatography
to afford methyl
(AcOEt:n-hexane=1:10)
4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoate (0.478 g, 88%). To a suspension
of the above ester (0.385 g, 1.10 mmol) in EtOH (10 ml) was added 2 M aqueous NaOH (7.5 ml).
The reaction mixture was stirred at 60°C for 1 h, then cooled, acidified by adding 2 M aqueous HCl
and extracted with CHCl3. Usual work-up gave a residue, which was purified by recrystallization
1
from EtOH to afford 7a (0.348 g, 94%). 7a: Colorless needles (EtOH); mp >300°C; H NMR
(DMSO-d6) : 1.21-1.34 (2H, m), 1.73-1.99 (6H, m), 2.55-2.66 (1H, m), 2.80-2.85 (4H, m), 7.49 (2H,
s), 7.90 (4H, s), 10.33 (1H, s); HR-ESI-MS m/z: 334.1430 ([M-H]+, calcd for C21H20NO3, 334.1443).
6-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carboxamido]nicotinic acid (8a): 61% yield.
Colorless powder (EtOH/CHCl3); mp > 300°C; 1H NMR (DMSO-d6) : 1.20-1.34 (2H, m), 1.68-1.80
(2H, m), 1.82-1.99 (4H, m), 2.55-2.62 (1H, m), 2.78-2.83 (4H, m), 7.58 (2H, s), 8.30 (1H, s), 8.31
(1H, s), 8.88 (1H, d, J=1.8 Hz), 10.93(1H, s); HR-ESI-MS m/z: 335.1390 ([M-H]+, calcd for
C20H19N2O3, 335.1396).
5-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carboxamido]pyridine-2-carboxylic acid (9a): 69%
1
yield. Pale yellow powder (EtOH); mp 219-220°C; H NMR (DMSO-d6) : 1.19-1.32(2H, m),
1.71-1.78 (2H, m), 1.82-1.87 (2H, m), 1.88-1.97 (2H, m), 2.53-2.60 (1H, m), 2.78-2.83 (4H, m), 7.50
(2H, s), 8.04 (1H, d, J=8.4 Hz), 8.37 (1H, dd, J=8.4, 2.7 Hz), 9.01 (1H, d, J=2.7 Hz), 10.55 (1H, s);
HR-ESI-MS m/z: 335.1384 ([M-H]+,
calcd for C20H19N2O3, 335.1396).
5-[(5,6,6a,7,8,9-Hexahydro-4H-2-phenalenyl)carboxamido]thiophene-2-carboxylic acid (10a):
1
36% yield. Colorless powder (AcOEt/n-hexane); mp 259-261°C; H NMR (DMSO-d6) : 1.20-1.32
(2H, m), 1.71-1.78 (2H, m), 1.79-1.87 (2H, m), 1.89-1.98 (2H, m), 2.53-2.61 (1H, m), 2.78-2.83 (4H,
m), 6.90 (1H, d, J=4.2 Hz), 7.52 (2H, s), 7.54 (1H, d, J=4.2 Hz), 11.74 (1H, s); HR-ESI-MS m/z:

340.1007([M-H]+, calcd for C19H18NO3S, 340.1007).
2-Fluoro-4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic acid (11a): 80%
yield. Colorless needles (AcOEt/n-hexane); mp >300°C; 1H NMR (DMSO-d6) : 1.21-1.34 (2H, m),
1.74-1.80 (2H, m), 1.83-1.89 (2H, m), 1.92-1.99 (2H, m), 2.53-2.62 (1H, m), 2.80-2.85 (4H, m), 7.49
(2H, s), 7.65 (1H, dd, J=8.7, 2.1 Hz), 7.81-7.91 (2H, m), 10.51 (1H, s); HR-ESI-MS m/z:
352.1351([M-H]+, calcd for C21H19FNO3, 352.1349).
2-Chloro-4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic acid (12a): 72%
1
yield. Colorless needles (AcOEt/n-hexane); mp 281-282°C; H NMR (DMSO-d6) : 1.21-1.34 (2H,
m), 1.73-1.80 (2H, m), 1.82-1.89 (2H, m), 1.92-1.99 (2H, m), 2.56- 2.62 (1H, m), 2.80-2.85 (4H, m),
7.49 (2H, s), 7.80-7.87 (2H, m), 8.05 (1H, d, J=2.1 Hz), 10.43 (1H, s); HR-ESI-MS m/z: 368.1035
([M-H]+, calcd for C21H19ClNO3, 368.1053).
2-Hydroxy-4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic acid (13a): 79%
yield. Colorless prisms (AcOEt/n-hexane); mp 267-267.5°C; 1H NMR (DMSO-d6) : 1.15-1.33 (2H,
m), 1.68-1.80 (2H, m), 1.82-1.89 (2H, m), 1.91-1.99 (2H, m), 2.53-2.61 (1H, m), 2.79-2.85 (4H, m),
7.32 (1H, dd, J=8.7, 2.1 Hz), 7.47 (2H, s), 7.53 (1H, d, J=2.1 Hz), 7.74 (1H, d, J=8.7 Hz), 10.29 (1H,
s); HR-ESI-MS m/z: 350.13906 ([M-H]+, calcd for C21H20NO4, 350.1392).
2-Methoxy-4-[(5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic acid (14a): 64%
1
yield. Colorless needles (AcOEt/n-hexane); mp 206-208°C; H NMR (DMSO-d6) : 1.21-1.34 (2H,
m), 1.74-1.80 (2H, m), 1.84-1.89 (2H, m), 1.92-1.99 (2H, m), 2.52-2.56 (1H, m), 2.80-2.85 (4H, m),
3.78 (3H, s), 7.35 (1H, d, J=8.1Hz), 7.50 (2H, s), 7.56-7.62 (2H, m), 10.22 (1H, s); HR-ESI-MS m/z:
364.1535 ([M-H]+, calcd for C22H22NO4, 364.1549).
4-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carbamoyl]benzoic acid (3b) and
analogs (4b-6b)
Following
the
procedure
used
for
3b
synthesizing
3a
from
from
5,6,6a,7,8,9-hexahydro-4H-2-phenalenylamine,
was obtained
6a-methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenylamine46 in 71% yield. 3b: Colorless needles
1
(AcOEt/n-hexane); mp 282-283°C; H NMR (DMSO-d6) : 1.11 (3H, s), 1.42 (2H, td, J=12.8, 4.9
Hz), 1.64 (2H, dt, J=12.8, 4.0 Hz), 1.71- 1.80 (2H, m), 1.93-2.09 (2H, m), 2.72 (2H, dt, J=17.4, 8.7
Hz), 2.85 (2H, ddd, J=17.1, 7.8, 3.0 Hz), 7.28 (2H, s), 8.01 (2H, d, J=8.4 Hz), 8.05 (2H, d, J=8.4 Hz),
10.13(1H, s); HR-ESI-MS m/z: 348.1600 ([M-H]+, calcd for C22H22NO3, 348.1600).
6-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carbamoyl]nicotinic acid (4b): 73% yield.
Pale yellow needles (AcOEt/n-hexane); mp 212-213°C; 1H NMR (CDCl3) : 1.17 (3H, s), 1.51 (2H,
td, J=12.9, 5.1 Hz), 1.69 (2H, dt, J=12.9, 3.9 Hz), 1.77-1.88 (2H, m), 2.00-2.16 (2H, m), 2.83 (2H, dt,
J=17.4, 8.7 Hz), 2.96 (2H, ddd, J=17.3, 8.1, 3.2 Hz), 7.31 (2H, s), 8.42 (1H, d, J=8.1 Hz), 8.57 (1H,
dd, J=8.1, 1.8 Hz), 9.26 (1H, d, J=1.8 Hz), 9.87(1H, s); HR-ESI-MS m/z: 349.1536 ([M-H]+, calcd

for C21H21N2O3, 349.1552).
5-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carbamoyl]pyridine-2-carboxylic
acid
1
(5b): 86% yield. Pale yellow powder (AcOEt/n-hexane); mp 199-200°C; H NMR (DMSO-d6) :
1.09(3H, s), 1.39 (2H, td, J=12.9, 5.1 Hz), 1.62 (2H, dt, J=12.6, 3.6 Hz), 1.68-1.78 (2H, m),
1.91-2.06 (2H, m), 2.70 (2H, dt, J=17.1, 8.7 Hz), 2.79-2.88 (2H, m), 7.25 (2H, s), 8.13 (1H, d, J=8.1
Hz), 8.40 (1H, dd, J=8.1, 2.1 Hz), 9.12 (1H, d, J=2.1 Hz), 10.30 (1H, s); HR-ESI-MS m/z: 349.1527
([M-H]+, calcd for C21H21N2O3, 349.1552).
5-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carbamoyl]thiophene-2-carboxylic acid
1
(6b): 69% yield. Pale yellow powder (AcOEt/n-hexane); mp 271-272°C; H NMR (DMSO-d6) :
1.08 (3H, s), 1.38 (2H, td, J=12.9, 5.1 Hz), 1.61 (2H, dt, J=12.6, 3.9 Hz), 1.68-1.79 (2H, m),
1.88-2.04 (2H, m), 2.68 (2H, dt, J=17.4, 8.7 Hz), 2.82 (2H, ddd, J=17.7, 8.1, 3.3 Hz), 7.20 (2H, s),
7.72 (1H, d, J=3.9 Hz), 7.94 (1H, d, J=3.9 Hz), 10.16 (1H, s); HR-ESI-MS m/z: 354.1158 ([M-H]+,
calcd for C20H20NO3S, 354.1164).
4-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic acid (7b) and
analogs (8b-14b)
Following
the
procedure
used
for
synthesizing
7b was
7a
from
from
5,6,6a,7,8,9-hexahydro-4H-phenalene-2-carboxylic
acid,
obtained
6a-methyl-5,6,6a,7,8,9-hexahydro-4H-phenalene-2-carboxylic acid46 in 55% yield. 7b: Colorless
1
prisms (AcOEt/n-hexane); mp 283.5-285°C; H NMR (DMSO-d6) : 1.14 (3H, s), 1.45 (2H, td,
J=12.8, 4.8 Hz), 1.69 (2H, dt, J=12.8, 3.8 Hz), 1.74-1.83 (2H, m), 1.95-2.11 (2H, m), 2.81 (2H, dt,
J=17.4, 8.7 Hz), 2.96 (2H, ddd, J=17.0, 7.8, 2.9 Hz), 7.45 (2H, s), 7.87 (2H, d, J=8.9 Hz), 7.92 (2H,
d, J=8.9 Hz), 10.34(1H, s); HR-ESI-MS m/z: 348.1582 ([M-H]+, calcd for C22H22NO3, 348.1600).
6-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]nicotinic acid (8b): 69%
yield. Colorless powder (EtOH/CHCl3); mp >300°C; 1H NMR (DMSO-d6) : 1.14 (3H, s), 1.48 (2H,
td, J=12.9, 5.1 Hz), 1.68 (2H, dt, J=12.9, 4.4 Hz), 1.75- 1.84 (2H, m), 1.94-2.11 (2H, m), 2.80 (2H,
dt, J=17.3, 8.6 Hz), 2.95 (2H, ddd, J=17.4, 7.7, 3.2 Hz), 7.57 (2H, s), 8.29-8.32 (2H, m), 8.87 (1H, s),
10.88 (1H, s); HR-ESI-MS m/z: 349.1534 ([M-H]+, calcd for C21H21N2O3, 349.1552).
5-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]pyridine-2-carboxylic acid
1
(9b): 54% yield. Colorless needles (EtOH); mp 222-223°C; H NMR (DMSO-d6) : 1.11 (3H, s),
1.43 (2H, td, J=12.9, 4.8 Hz), 1.66 (2H, dt, J=12.9, 3.6 Hz), 1.71-1.81 (2H, m), 1.93-2.09 (2H, m),
2.80 (2H, dt, J=17.4, 8.7 Hz), 2.94 (2H, ddd, J=17.4, 8.1, 3.3 Hz), 7.47 (2H, s), 8.04 (1H, d, J=8.7
Hz), 8.36 (1H, dd, J=8.7, 2.4 Hz), 9.00 (1H, d, J=2.4 Hz), 10.54 (1H, s); HR-ESI-MS m/z: 349.1538
([M-H]+, calcd for C21H21N2O3, 349.1552).
5-[(6a-Methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]thiophene-2-carboxylic acid
(10b): 44% yield. Colorless powder (AcOEt/n-hexane); mp 259-260°C; 1H NMR (DMSO-d6) : 1.11

(3H, s), 1.42 (2H, td, J=12.9, 4.5 Hz), 1.62-1.69 (2H, m), 1.72-1.80 (2H, m), 1.92- 2.08 (2H, m),
2.79 (2H, dt, J=17.3, 8.7 Hz), 2.94 (2H, ddd, J=17.7, 8.1, 3.3 Hz), 6.91 (1H, d, J=4.2 Hz), 7.48 (2H,
s), 7.61 (1H, d, J=4.2 Hz), 11.80 (1H, s); HR-ESI-MS m/z: 354.1153 ([M-H]+, calcd for C20H20NO3S,
354.1164).
2-Fluoro-4-[(6a-methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic
acid
(11b): 74% yield. Colorless prisms (AcOEt/n-hexane); mp 276-278°C; 1H NMR (DMSO-d6) : 1.14
(3H, s), 1.45 (2H, td, J=12.9, 5.1 Hz), 1.67 (2H, dt, J=12.9, 3.9 Hz), 1.74-1.85 (2H, m), 1.95-2.11
(2H, m), 2.82 (2H, dt, J=17.3, 8.7 Hz), 2.96 (2H, ddd, J=17.3, 7.8, 3.3 Hz), 7.45 (2H, s), 7.63 (1H, d,
J=8.7 Hz), 7.79-7.91 (2H, m), 10.50 (1H, s); HR-ESI-MS m/z: 366.1491([M-H]+, calcd for
C22H21FNO3, 366.1505.
2-Chloro-4-[(6a-methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic
acid
(12b): 79% yield. Colorless prisms (AcOEt/n-hexane); mp 244-246°C; 1H NMR (DMSO-d6) : 1.13
(3H, s), 1.45 (2H, td, J=12.9, 5.1 Hz), 1.68 (1H, dt, J=12.9, 3.9 Hz), 1.75-1.83 (2H, m), 1.95-2.10
(2H, m), 2.81 (2H, dt, J=17.3, 8.7 Hz), 2.96 (2H, ddd, J=17.1, 7.6, 3.0 Hz), 7.46 (2H, s), 7.81 (1H,
dd, J=8.7, 1.8 Hz), 7.87 (1H, d, J=8.7 Hz), 8.04 (1H, d, J=1.8 Hz), 10.43 (1H, s); HR-ESI-MS m/z:
382.1203 ([M-H]+, calcd for C22H21ClNO3, 382.1210).
2-Hydroxy-4-[(6a-methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic
acid
(13b): 87% yield. Colorless prisms (AcOEt/n-hexane); mp 244-245°C; 1H NMR (DMSO-d6) : 1.13
(3H, s), 1.45 (2H, td, J=12.9, 5.1 Hz), 1.68 (2H, dt, J=12.9, 3.9 Hz), 1.74-1.84 (2H, m), 1.95-2.11
(2H, m), 2.81 (2H, dt, J=17.3, 8.4 Hz), 2.96 (2H, ddd, J=17.4, 7.8, 3.0 Hz), 7.31 (1H, dd, J=8.7, 1.8
Hz), 7.43 (2H, s), 7.51 (1H, d, J=1.8 Hz), 7.74 (1H, d, J=8.7 Hz), 10.29 (1H, s); HR-ESI-MS m/z:
364.1539 ([M-H]+, calcd for C22H22NO4, 364.1549).
2-Methoxy-4-[(6a-methyl-5,6,6a,7,8,9-hexahydro-4H-2-phenalenyl)carboxamido]benzoic
acid
(14b): 68% yield. Colorless needles (AcOEt/n-hexane); mp 184-186°C; 1H NMR (DMSO-d6) : 1.14
(3H, s), 1.46 (2H, td, J=12.9, 5.4 Hz), 1.69 (2H, dt, J=12.5, 3.8 Hz), 1.75-1.85 (2H, m), 1.95-2.01
(2H, m), 2.82 (2H, dt, J=17.4, 8.7 Hz), 2.96 (2H, ddd, J=17.3, 7.7, 3.3 Hz), 3.77 (3H, s), 7.41 (1H,
dd, J=8.6, 2.1 Hz), 7.46 (2H, s), 7.55-7.57 (2H, m), 10.19 (1H, s); HR-ESI-MS m/z: 378.1696
([M-H]+, calcd for C23H24NO4, 378.1705).
6.3. Synthesis of benzo[ef]heptalene derivatives (15-22)
4-[(5,6,7,7a,8,9,10,11-Octahydro-4H-2-benzo[ef]heptalenyl)carbamoyl]benzoic acid (15) and
analog (16)
Following
the
procedure
used
for
15
synthesizing
3a
from
from
5,6,6a,7,8,9-hexahydro-4H-2-phenalenylamine,
was obtained
5,6,7,7a,8,9,10,11-octahydro-4H-2-benzo[ef]heptalenylamine46 in 67% yield. 15: Colorless needles

1
(AcOEt/n-hexane); mp 280-281°C; H NMR (DMSO-d6) : 1.34-1.59 (6H, m), 1.69-1.88 (6H, m),
2.71-2.80 (4H, m), 3.10-3.21 (1H, m), 7.27 (2H, s), 7.95 (2H, d, J=8.1 Hz), 8.05 (2H, d, J=8.1 Hz),
10.17 (1H, s); HR-ESI-MS m/z: 362.1736 ([M-H]+, calcd for C23H24NO3, 362.1756).
6-[(5,6,7,7a,8,9,10,11-Octahydro-4H-2-benzo[ef]heptalenyl)carbamoyl]nicotinic acid (16): 81%
1
yield. Pale yellow needles (AcOEt/n-hexane); mp 239-240°C; H NMR (CDCl3) : 1.53-1.66 (6H,
m), 1.79-1.91 (6H, m), 2.84-2.88 (4H, m), 3.19-3.26 (1H, m), 7.38 (2H, s), 8.39 (1H, d, J=8.1 Hz),
8.54 (1H, d, J=8.1 Hz), 9.24 (1H, s), 9.86 (1H, s); HR-ESI-MS m/z: 363.1694 ([M-H]+, calcd for
C22H23N2O3, 363.1709).
4-[(5,6,7,7a,8,9,10,11-Octahydro-4H-2-benzo[ef]heptalenyl)carboxamido]benzoic acid (17) and
analogs (18-22)
Following
the
procedure
used
for
synthesizing
17 was
7a
from
from
17:
5,6,6a,7,8,9-hexahydro-4H-phenalene-2-carboxylic
5,6,7,7a,8,9,10,11-octahydro-4H-benzo[ef]heptalene-2-carboxylic acid46 in 58% yield.
acid,
obtained
1
Colorless needles (AcOEt/n-hexane); mp 275-276°C; H NMR (DMSO-d6) : 1.37-1.60 (6H, m),
1.70-1.90 (6H, m), 2.84-2.87 (4H, m), 3.20-3.31 (1H, m), 7.48 (2H, s), 7.83 (2H, d, J=8.7 Hz), 7.89
(2H, d, J=8.7 Hz), 10.32 (1H, s); HR-ESI-MS m/z: 362.1747 ([M-H]+, calcd for C23H24NO3,
362.1756).
6-[(5,6,7,7a,8,9,10,11-Octahydro-4H-2-benzo[ef]heptalenyl)carboxamido]nicotinic acid (18): 6%
1
yield. Colorless needles (EtOH/CHCl3); mp >300°C; H NMR (DMSO-d6) : 1.44-1.62 (6H, m),
1.73-1.93 (6H, m), 2.87-2.91 (4H, m), 3.25-3.68 (1H, m), 7.63 (2H, s), 8.28-8.91 (2H, m), 8.86 (1H,
s), 10.87 (2H, s); HR-ESI-MS m/z: 363.1709 ([M-H]+, calcd for C22H24N2O3, 363.1709).
2-Fluoro-4-[(5,6,7,7a,8,9,10,11-octahydro-4H-2-benzo[ef]heptalenyl)carbamoyl]benzoic
acid
1
(19): 23% yield. Colorless needles (AcOEt/n-hexane); mp 266-267°C; H NMR (DMSO-d6) :
1.43-1.56 (6H, m), 1.74-1.91 (6H, m), 2.88 (4H, t, J=5.7 Hz), 3.11-3.19 (1H, m), 7.50 (2H, s), 7.62
(1H, dd, J=8.7, 2.1 Hz), 7.78-7.89 (2H, m), 10.47 (1H, s); HR-ESI-MS m/z: 380.1648 ([M-H]+, calcd
for C23H23FNO3, 380.1662).
2-Chloro-4-[(5,6,7,7a,8,9,10,11-octahydro-4H-2-benzo[ef]heptalenyl)carbamoyl]benzoic
acid
1
(20): 43% yield. Colorless needles (AcOEt/n-hexane); mp 243-244°C; H NMR (DMSO-d6) :
1.43-1.59 (6H, m), 1.72-1.90 (6H, m), 2.87 (4H, t, J=5.4 Hz), 3.12-3.18 (1H, m), 7.50 (2H, s), 7.79
(1H, dd, J=8.4, 1.8 Hz), 7.84 (1H, d, J=8.4 Hz), 8.02 (1H, d, J=1.8 Hz), 10.38 (1H, s); HR-ESI-MS
m/z: 396.1355 ([M-H]+, calcd for C23H23ClNO3, 396.1366).
2-Hydroxy-4-[(5,6,7,7a,8,9,10,11-octahydro-4H-2-benzo[ef]heptalenyl)carbamoyl]benzoic acid
1
(21): 17% yield. Colorless needles (AcOEt/n-hexane); mp 242-243°C; H NMR (DMSO-d6) :
1.43-1.59 (6H, m), 1.71-1.91 (6H, m), 2.87 (4H, t, J=5.4 Hz), 3.06-3.13 (1H, m), 7.29 (1H, dd, J=8.7,
1.8 Hz), 7.48 (2H, s), 7.49 (1H, d, J=1.8 Hz), 7.72 (1H, d, J=8.7 Hz), 10.25 (1H, s); HR-ESI-MS

m/z: 378.1702 ([M-H]+, calcd for C23H24NO4, 378.1705).
2-Methoxy-4-[(5,6,7,7a,8,9,10,11-octahydro-4H-2-benzo[ef]heptalenyl)carbamoyl]benzoic acid
1
(22): 41% yield. Colorless needles (AcOEt/n-hexane); mp 233-234°C; H NMR (DMSO-d6) :
1.43-1.56 (6H, m), 1.72-1.91 (6H, m), 2.88 (4H, t, J=5.4 Hz), 3.06-3.15 (1H, m), 3.78 (3H, s), 7.43
(1H, d, J=8.7 Hz), 7.50 (2H, s), 7.56-7.63 (2H, m), 10.21(1H, s); HR-ESI-MS m/z: 392.1844
([M-H]+, calcd for C24H26NO4, 392.1862).
Acknowledgment
The authors thank Dr. M. Kurihara and Dr. T. Shoda, Division of Organic Chemistry, National
Institute of Health Sciences, for HR-ESI-MS measurement.
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Figure Legends
Figure 1.
Structures of ATRA, 9cRA, and Am80.
Figure 2.
Synthesis of metacyclophane derivatives (1, 2). Reagents: (i) NaNO3, H2SO4; (ii) H2, 10% Pd/C; (iii)
Ac2O, pyridine; (iv) HNO3, H2SO4; (v) HCl; (vi) NaNO2, H2SO4, EtOH; (vii) terephthalic acid
monomethyl ester chloride, pyridine; (viii) 2 M aq. NaOH, EtOH; (ix) a) CH3CN, BCl3, AlCl3 b) 2
M aq. HCl ; (x) 2.5 M aq. NaOH, Br2; (xi) a) SOCl2 b) methyl 4-aminobenzoate, 4-DMAP, pyridine.
Figure 3.
Synthesis of phenalene derivatives (3a, b-14a, b). Reagents: (i) AcCl, AlCl3 (ii) 2.5 M aq. NaOH,
Br2; (iii) a) SOCl2 b) aq. NaN3 c) aq. AcOH d) HCl, MeOH; (iv) ClOC-Ar-COOMe, pyridine; (v) 2
M aq. NaOH, EtOH; (vi) a) SOCl2 b) H2N-Ar-COOMe; 4-DMAP, pyridine.
Figure 4.
Synthesis of benzo[ef]heptalene derivatives (15-22). Reagents: (i) AcCl, AlCl3 (ii) 2.5 M aq. NaOH,
Br2; (iii) a) SOCl2 b) aq. NaN3 c) aq. AcOH d) HCl, MeOH; (iv) ClOC-Ar-COOMe, pyridine; (v) 2
M aq. NaOH, EtOH; (vi) a) SOCl2 b) H2N-Ar-COOMe; 4-DMAP, pyridine.
a Ar-COOHs are the same as shown in Figure 3.
Figure 5.
Transcriptional activities measured by means of reporter gene assay in Cos-1 cells expressing
GAL4-RAR (●), GAL4-RAR (□), and GAL4-RAR (▲). Data are mean values of fold increase (vs
DMSO) measured by two or more experiments. The horizontal scale is the molar concentration of
added compound.
Table 1.
Transcriptional activation assay data.a
a
Data are mean values of fold induction (vs DMSO) at 100 nM measured by two or more
experiments.
b
Metacyclophane derivatives (1, 2); Phenalene derivatives (3a,b-14a,b); Benzo[ef]heptalene
derivatives (15-22).
c Ar-COOHs are the same as shown in Figure 3.
d One experiment.

e Not determined.
Table 2.
HL-60 cell differentiation-inducing activity.a
a Data are mean values of the percentage of differentiated cells evaluated from NBT reduction assay
at 10 nM and 100 nM.
b Not determined.

Fig1.tif

Fig2.tif

Fig3.tif

Fig4.tif

Fig5.jpg

Table 1. Transcriptional activation assay data.a
Relative fold induction
Compoundb Ar-COOHc
RAR
RAR
RAR
ATRA
Am80
1
55
66
33
37
30
40
34
34d
1
35
24
65
5
A
A
A
A
B
B
C
C
D
D
A
A
B
B
C
C
D
D
E
8
1
2
13
1
3a
5
1
3b
12
1
4a
16
7
4b
26
2d
1d
1d
1d
1d
3
5a
N. D.e
N. D.e
N. D.e
N. D.e
18
5b
2
6a
1d
6b
3d
7a
51
56
50
52
24
23
20d
22
51
68
45
59d
38
51d
28d
38d
42
40d
62
85
83
63
63
43d
7b
20
4
8a
40
20
25
1d
1d
1d
1
8b
40
9a
N. D.e
N. D.e
N. D.e
1d
9b
10a
10b
11a
11b
12a
12b
13a
13b
14a
14b
15
7d
2
E
13
2
F
6
8d
1
1e
F
G
G
H
H
A
B
A
B
E
6
2
7e
1d
1d
1d
1
2d
3d
13
16
17
2d
10
56
5
17
27
18
45
19
19
20
F
13
2
21
G
H
11
1d
2
2d
22
a Data are mean values of fold induction (vs DMSO) at 100 nM measured by two or more experiments.
b Metacyclophane derivatives (1, 2); Phenalene derivatives (3a,b-14a,b); Benzo[ef]heptalene derivatives (15-22).
c Ar-COOHs are the same as shown in Figure 3.
d One experiment.
e Not determined.

Table 2. HL-60 cell differentiation-inducing activity.a
NBT reduction (%)
Compound
10 nM
46
60
16
30
7
100 nM
71
ATRA
Am80
1
68
37
2
38
3a
18
3b
12
2
N. D.b
5
4a
4b
5
16
7a
27
36
54
41
49
18
16
19
24
17
7
38
7b
N. D.b
59
8a
8b
61
11a
11b
12a
12b
13a
13b
14a
14b
15
60
29
37
21
42
32
10
5
17
13
34
28
18
29
53
17
40
19
44
20
35
21
41
a Data are mean values of the percentage of differentiated cells evaluated from NBT reduction assay at 10 nM and 100 nM.
b Not determined.