Identification and structure - Activity relationships of chromene-derived selective estrogen receptor modulators for treatment of postmenopausal symptoms

7544 J. Med. Chem. 2009, 52, 7544–7569

DOI: 10.1021/jm900146e

Identification and Structure-Activity Relationships of Chromene-Derived Selective

Estrogen Receptor Modulators for Treatment of Postmenopausal Symptoms

Nareshkumar Jain,* Jiayi Xu, Ramesh M. Kanojia, Fuyong Du, Guo Jian-Zhong, Emmanuel Pacia,

Muh-Tsann Lai, Amy Musto, George Allan, Michael Reuman, Xun Li, DoWon Hahn, Martin Cousineau,

Sean Peng, David Ritchie, Ronald Russell, Scott Lundeen, and Zhihua Sui

Johnson & Johnson Pharmaceutical Research & Development LLC, 665 Stockton Drive, Exton, Pennsylvania 19341

Received February 4, 2009

As part of a program aimed at the development of selective estrogen receptor modulators (SERMs),

novel chromene scaffolds, benzopyranobenzoxapanes, were discovered. Many compounds showed

binding affinity as low as 1.6-200 nM, displayed antagonist behaviors in the MCF-7 human breast

adenocarcinoma cell line as well in Ishikawa cell line with IC₅₀values in the range 0.2-360 nM. On the

basis of the side chain substitution, various compounds demonstrated strong inhibitory activity in anti-

uterotropic assay. Compound 7-(R) and its major metabolites 5-(R) and 6-(R) were evaluated in several

in vivo models of estrogen action. Relative to a full estrogen agonist (ethynyl estradiol) and the SERM

raloxifene, 7-(R) was found to be a potent SERM that behaved as antagonist in the uterus and exhibited

estrogen agonistic activity on bone, plasma lipids, hot flush, and vagina. The overall pharmacokinetic

profile and stability were significantly improved compared to those of the phase 2 development

compound 9-(R).

Introduction

tamoxifen (TAM) and raloxifene (RAL) have shown their

high therapeutic potential for estrogen-related diseases. Thus,

TAM, the first SERM approved for breast cancer, is effective

for all stages of hormone-dependent breast cancer, whereas

RAL is indicated for the prevention and treatment of osteo-

porosis in postmenopausal women.⁵These SERMs have

beneficial effects on bone and lipid metabolism while antag-

onizing the effects of estrogens on the uterus and breasts.

However, there are no SERMs that have been reported to

have a clinical beneficial effect on hot flush and vaginal

dryness.^4b,6

Compound 9-(R) is a SERM previously reported by our

group that has an improved preclinical profile compared to

SERMs that are currently marketed or are in late stage

development.^7aThese improvements include the ability to

protect against hot flushes and to improve vaginal fluidity in

rodent models. These unique activities accompany the ability

to protect against bone loss, lower plasma cholesterol levels,

and block estrogen action in the breast and uterus, which are

properties of the current SERMs. In spite of the unique

pharmacological profile of compound 9-(R), there are limita-

tions to the molecule. First, it isa prodrug, i.e., pivalategroups

on the A and D rings of the benzopyran backbone of the

molecule are prone to hydrolysis by esterase.⁷Second, there

are issues with the stability of the active metabolite and some

of the intermediates in the synthesis of compound 9-(R).^7bIn

this article, we present structure-activity relationship of a

novel chromene derived SERM and identification of a com-

pound 7-(R) as a backup NCE candidate for our clinical

compound 9-(R) with potential to move into clinical trials.

The compound maintains the preclinical profile of our lead

compound 9-(R) and has improved stability, pharmacoki-

netic, and pharmacological properties (Figure 1).

The endogenous steroid estrogen is a critical mediator of

many physiologicalfunctions related to development, growth,

and maintenance of a large number of tissues in both females

and males. Selective estrogen receptor modulators (SERMs^a)

are compounds that act as estrogen agonists on selected

targets while being estrogen antagonists on others.¹Hot flush

and vaginal dryness are the most common symptoms asso-

ciated with menopause in women. Hot flush is characterized

by the sudden onset of hot feeling, sweating, palpitation, and

anxiety and affects approximately 75% of women as they

enter menopause.²More than 50% of postmenopausal wo-

men experience lack ofvaginallubrication thatleads toseveral

genital complaints associated with a diminished frequency of

all forms of sexual behavior.³Indeed, hormone therapy (HT)

alleviates both of these symptoms in 80-90% of women and

has been recognized as the most effective treatment for hot

flush and vaginal dryness.⁴Despite the effectiveness of HT on

these symptoms as well as the beneficial effects on bone and

plasma cholesterol levels, its use has been limited because of

side effects such as vaginal bleeding, breast tenderness, con-

cerns about increased risks of breast cancer, and more re-

cently, the concerns about cardiovascular safety in about 25%

of patients. Given the clinical evidence that HT has an

unfavorable benefit/risk ratio, there is an intense need for an

alternative therapy for hot flush and vaginal dryness. Both

*To whom correspondence should be addressed. Current address:

The Chemistry Research Solution LLC, 1531 High Country Road,

Downingtown, PA 19335. Phone: 908-268-2336. Fax: 800-699-9126.

E-mail: njain@TCRS-US.com, DrNFJain@gmail.com.

^aAbbreviations: ER, estrogen receptor; HRT, hormone replacement

therapy; SERM, selective estrogen receptor modulator; TAM, tamox-

ifen; RAL, raloxifene.

r

pubs.acs.org/jmc

Published on Web 04/14/2009

2009 American Chemical Society

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7545

Figure 1. Structures of estradiol and representative SERMs.

Figure 2. Degradation mechanisms of bisbenzopyran I.

Results and Discussion

linker resulted in a unique pharmacological profile, relieving

hot flush as well as vaginal dryness while having beneficial

effects on bone and lipids in preclinical animal models.

However, some bisbenzopyran analogues with hydroxyl

groups on both ends of the molecules such as Ia were found

to be unstable in air, in light, and at elevated temperature.^7b

We discovered that after prolonged dissolution in methanol

for an extended time, the methylene group in bisbenzopyran

Ia was substituted with a methoxy group to yield Ic. We

reasoned that the formation of the oxonium Ib is the major

mechanism for the instability. In structure Ib, the aromatic

character and the resonance contribution from the D ring

stabilize the oxonium ion. We explored ways to block the

oxidation process by introducing gem-dimethyls to the methy-

lene group.^7bAlthough the oxidation was prevented, Id did

Our working hypothesis is that SERMs with beneficial

effects on hot flush and potentially vaginal dryness (i.e.,

agonists on these tissues) should have a conformation flex-

ibility in the C/D region similar to that of the natural ligand

17β-estradiol. In 30 (EM-652) the D ring is connected to the B

ring with a rotatable bond and hence can adopt various

conformations.^5cIn contrast, 31 (LY-357489) is a planar

structure in this region. We envisioned that structures possess

flexibility in the C/D region between that of 30 and 31 might

offer distinct pharmacological profiles.^5dIn other words, the

former may be too flexible in the C/D region while the latter

might too rigid. In our previous communication, we had

reported that novel chromene-derived bisbenzopyrans where

CdC bond in the C ring of 31 was replaced with a -CH₂-O-

7546 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Figure 3. Design of seven- and eight-membered analogues.

Scheme 1. Synthesis of Key Lactal Intermediates^a

^aReagent and reaction conditions: (a) Ac₂O, Et₃N, reflux, 36 h; (b) LiHMDS (1.5 equiv) MOMCl, THF, -30 to -10 °C; (c) BBr₃, CH₂Cl₂, room

temp; (d) diethylazidodicarboxylate, DEAD, THF, PPh₃, room temp; (e) TBSCl, Et₃N, DCM, room temp; (f) DIBAL-H, toluene, DCM, -78 °C.

not show strong affinity to ERs in the in vitro binding assays

(Figure 2).

evaluations of these novel benzopyranobezooxapane (II)

series are discussed.⁸

To maintain certain conformation constrains for D-ring

rotation while preventing oxidation from occurring, we

decided to replace the -CH₂O- linker in the C-ring of the

bisbenzopyrans with a -CH₂CH₂O- or -CH₂CH₂CH₂O-

linker to create the seven- and eight-membered ring deriva-

tives as shown in Figure 3. We hoped that the change

in planarity in C-ring would not affect the biological profile

but prevent the formation of the oxonium intermediate

associated with stability. Herein, we report new chromene-

derived benzopyranobenzoxapane scaffold for SERMs. The

synthesis, structure-activity relationships, and biological

Chemistry. The basic tetracyclic ring system was synthe-

sized using Perkin reaction followed by cyclization. In order

to increase the throughput of the synthesis, several different

routes were adopted to facilitate the introduction of the

side chains. Most of the compounds were obtained in

enantiomerically pure form by HPLC using ChiralPAK

AD columns.^7i,8

Synthesis of Tetracyclic Lactol 14. The preparation of fully

functionalized benzopyranobenzoxapane system 14a was

achieved in four to five steps (Scheme 1). Modified Perkins

reaction of a mixture of 2-hydroxyacetophenones 27 and

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7547

Scheme 2. Introduction of Side Chain^a

i

^aReaction conditions: (a) 15 (ArMgx), THF, -78 °C; (b) conc HCl, toluene, 0 °C; (c) DEAD, Ph₃P, Pr₂NEt, 0 °C; (d) TBAF, THF, 0 °C; (e)

ChiralPAK AD column (ⁱPrOH was used as mobile phase).

substituted phenylacetic acid 28 in the presence of triethyl-

amine in refluxing acetic anhydride delivered coumarins 9a-

f in moderate to good yields. For the synthesis of benzopyr-

anobenzoxapane II we needed one carbon homologation

of 9. When Li homoenolates of 9a-f were reacted with

MOMCl, MOM homologated products 10a-f were ob-

tained in good yields (67-81%). Global deprotection using

BBr₃in CH₂Cl₂followed by cyclization under Mitsunobu

protocol gave 12a-f in 55-73% overall yields for two

steps. The construction of the key tetracyclic interme-

diates was achieved in two steps: (i) capping the phenolic

hydroxyl groups of 12 as tert-butyldimethylsilyl (TBDMS)

derivatives 13a-f; (ii) reduction with DIBAL-H to afford

lactol 14a-f.

General Synthesis of Benzopyranobenzoxapane (1). Ben-

zopyranobenzoxapanes with various substitutions at ring

A and ring B were synthesized as outlined in Scheme 2. The

addition of Grignard reagent of the aminoalkoxyphenyl side

chain 15 or the coresponding organolithio reagents to lactol

14 opened up the pyran ring B to afford the diol 16, which

recyclized to chromene 17 under Mitsunobu protocol or

more conveniently by acid treatment (concentrated HCl) at

low temperature in a hydrocarbon solvent such as toluene.

The removal of mono- or di-TBS groups from 17 with

tetrabutylammonium fluoride (TBAF) afforded the target

compounds 1-(() in racemic form. The benzopyranoben-

zoxapane 1-(() was resolved using preparative HPLC with

ChiralPAK AD column to yield optically pure compounds

(R) and (S) with optical purity of more than 95% ee in all

cases. The absolute stereochemistry was determined by

single X-ray crystal structure analysis.⁹

Synthesis of Iodobenzopyranobenzoxapanes 18 and 24. In

the synthesis of benzopyranobenzoxapane with various

amine groups at para- or meta-substituted side chain, the

iodo derivatives 18 and 24 served as the key intermedi-

ates. Grignard reagents 15a,b were freshly prepared and

were added to lactol to yield diols which upon treatment

with concentrated HCl yielded the recyclized alcohols

17-(() and 23-(() in very good yields. The racemic

mixtures of these alcohols were separated on chiral col-

umn AD and 20% IPA in hexanes as mobile phase to yield

optically pure alcohol 17 or 23-(R) or 17 or 23-(S). The

optically pure alcohol was reacted with PPh₃, imidazole,

and iodine to yield the corresponding iodides 18 and 24.

By use of this protocol, large amount of these intermedi-

ates (5-10 g) could be readily synthesized. Various sub-

stituted secondary amines were reacted with iodide 18 or

24 in acetonitrile at 60 °C in the presence of anhydrous

K₂CO₃to yield various amino side chain substituted

benzopyranobenzoxapanes 19 in good to moderate

yields. Deprotection of TBS groups using TBAF yielded

1 in about 30-40% overall yield in optically pure form.

The overall sequence is described in Scheme 3. This

sequence was also used for the preparation of meta-

substituted analogues 2.

For synthesis of carboxylic acid and ester derivative 1l and

1m, a modified route was used as described in Scheme 4. For

preparation of compound 1 (l-o) the corresponding alcohol

was oxidized to the corresponding acid 1l. This acid was

treated with freshly prepared (in situ) diazomethane to yield

the corresponding ester as described in Scheme 4 in good to

moderate yields.

7548 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Scheme 3. Introduction of Various Amino Groups into the Side Chain^a

^aReagent and conditions: (a) THF, -20 °C; (b) chiral separation was done with 50 cm ꢀ 100 cm chiral PaKAD chiral coloum, ⁱPrOH as mobile phase;

(c) PPh₃, imidazole, I₂; (d) R₁R₂NH/DMF, heat at 60 °C; (e) TBAF, THF, 0 °C.

Synthesis of Methoxybenzopyranobenzoxapanes 4a-5a.

The synthesis of dimethoxybenzopyranobenzoxapanes 7-(R)

and 7-(S) was achieved in one step from the corresponding

phenolic benzopyranobenzoxapanes 1a-(R) and 1a-(S),

respectively, by methylation using excess of TMSCHN₂

in the presence of an excess of Et₃N in almost quantitative

yield. Monomethoxybenzopyranobenzoxapanes 5-(R), 6-(R),

5-(S), 6-(S) were synthesized by generating a statistical

mixture of the monomethoxy and dimethoxy derivatives with

1.5 equiv of TMSCHN₂. After separation of the dimethoxy

derivative 7, the regiomeric mixtures of these optically

pure monomethoxy derivatives were separated on Chiral

PAK AD using IPA as mobile phase. Using this protocol, it

was possible to generate grams of 5-(R or S) and 6-(R or S)

(Scheme 5).

In Vitro and Immature Rat Uterotropic Assays. In Vitro

Assay. Compounds were tested in four in vitro assays. New

derivatives were screened in estrogen receptor β fluorescence

polarization assay.⁹This assay monitors binding of a fluor-

escent analogue of estrogen (Fluormone ES2, Panvera) to

the estrogen receptor. Plates are read in a fluorometer that

can be set to polarization mode. A decrease in fluorescence

relative to vehicle control is an indication of binding of a

compound to the receptor.¹⁰At the same time all new

derivatives were also tested for estrogen receptor R flash

plate assay. This assay monitors binding of radiolabeled

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7549

Scheme 4. Hydroxy and Carboxylic Acid Derivatives^a

^aReaction conditions: (a) Jones oxidation; (b) TMS-diazomethane; (c) TBAF, THF, 0 °C.

Scheme 5. Methoxy Derivatives^a

^aReaction conditions: (a) TMSCH₂N₂(1.5 equiv for 5 or 6 and 4.0 equiv for 7), Et₃N (4 equiv).

estrogen to the estrogen receptor. It is performed on a

BioMek 2000 (Beckman). Plates are read in a scintillation

counter (Packard Top Count); decreased counts are an

indication of binding of a compound to the receptor. The

assay was run according to the procedure described by Allan

et al.^10,11The compounds were then evaluated for its activity

in two cell-based functional assays, Ishikawa endometrial

cell alkaline phosphatase assay, and MCF-7 breast cancer

cell proliferation assay to determine the antagonist activity.

The alkaline phosphatase assay in human endometrial

Ishikawa cells was run according to the procedure described

by Albert et al.¹²with minor modification. Ishikawa cells

(from ATCC) were maintained in DMEM/F12 (1:1) phenol

red free medium (Gibco) supplemented with 10% calf serum

(Hyclone). Twenty-four hours prior to testing, the medium

was changed to DMEM/F12 (1:1) phenol red free containing

2% calf serum. Compounds to be tested in the agonist mode

were added to the culture media at varying concentrations.

Compounds to be treated in the antagonist mode were

prepared similarly, and 10 nM 17β-estradiol was also added

to the culture media. The cells were then incubated at 37 °C

for 3 days. On the fourth day, the media were removed,

1 volume of 1ꢀ dilution buffer (Clontech) was added to the

well followed by addition of 1 volume of assay buffer

(Clontech). The cells were then incubated at room tem-

perature for 5 min. One volume of freshly prepared chemi-

luminescence buffer (1 volume of chemiluminescent sub-

strate (CSPD) in 19 volumes of chemiluminescent enhancer

with final concentration of CSPD at 1.25 mM; Sigma

Chemical Co.) was added. The cells were incubated at room

temperature for 10 min and then quantified on a lumin-

ometer. The increase of chemiluminescence over vehicle

control was used to calculate the increase in alkaline phos-

phatase activity.

The MCF-7 cell proliferation assay was run according to

the procedure described by Welshons, Taylor, and Jones¹³

with minor modification. Briefly, MCF-7 cells (from Dr. C.

Jordan, Northwestern University) were maintained in RPMI

1640 phenol red free medium (Gibco) in 10% FBS

(Hyclone), supplemented with bovine insulin and nonessen-

tial amino acid (Sigma). The cells were initially treated with

4-hydoxyltamoxifen (10^-8M) and allowed to stand at 37 °C

for 24 h. Following this incubation with tamoxifen, the cells

were treated with compounds at various concentrations.

Compounds to be tested in the agonist mode were added to

the culture media at varying concentrations. Compounds to

be treated in the antagonist mode were prepared similarly,

and 10 nM 17β-estradiol was also added to the culture media.

The cells were incubated for 24 h at 37 °C. Following

this incubation, 0.1 μCi of ¹⁴C-thymidine (56 mCi/mmol,

Amersham) was added to the culture media and the cells

were incubated for an additional 24 h at 37 °C. The cells were

then washed twice with Hank’s buffered salt solution (HBSS)

(Gibco) and counted with a scintillation counter. The in-

crease in the ¹⁴C-thymidine in the compound treated cells

relative to the vehicle control cells was reported as percent

increase in cell proliferation.

Immature Rat Anti Uterotropic Studies. The compounds

with SERM-like properties act as estrogen agonist or an-

tagonist on uterus. It is well established that estrogens are

7550 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Figure 4. SAR studies and lead optimization.

Table 1. Comparison of Bisbenzopyran and Benzopyranobenzooxapane^a

compd

ERR binding IC₅₀(nM)

ERβ binding IC₅₀(nM)

Ishikawa IC₅₀(nM)^b

MCF-7 IC₅₀(nM)^c

uterotropic activity inhibition (%)^d

1a-(()

8a-(()

13

23

31

77

8

121

19

280

77

33

^aAll compounds were tested more than three times in these assays with high reproducibility. The average is shown here. ^bNo agonist activity was

found at 10 μM. ^cNo agonist activity was found at 10 μM. ^dInhibitions of estrone-stimulated uterine weight at 1 mg/kg.

known for their uterotropic activities to stimulate uterine

growth. The immature rat uterotropic model is used to get

a rapid and accurate assessment of the activity of a com-

pound in the uterus. This can be used in either the agonist

mode (compound alone) or antagonist mode (compound þ

estrogen). Because the animals have not matured sexually,

there is minimal endogenous estrogen to complicate the

evaluation. Immature rats that are unexposed to estrogen

are administered with an estrogen, estrone, for 3 days. The

uteri grow rapidly, and the weight of uterus increases sharply

in 3 days. Co-treatment with estrogen antagonist could block

the stimulation, while estrogen agonist synergistically en-

hances the stimulation. The difference between the weight of

uterus from vehicle control animals and that from treated

animals is a sensitive indicator of estrogen agonist or

antagonist activity. This model has been used as a classical

measure to evaluate activities of estrogen agonists and

antagonists including SERMs. The effects of these com-

pounds in this model have been predictive of the clinical

responses reported in women¹⁸. In the agonist mode and

antagonist mode, the test compounds were administered

orally once daily (1 mg/kg) for 3 days and the effect on

uterine wet weight was compared with vehicle, estrone,

tamoxifen, and raloxifene.^13-15

Structure-Activity Relationships. The overall effort for

SAR studies is summarized in Figure 4. The representative

seven- and eight-membered derivatives 1a-(() and 8a-(()

(Table 1) exhibited excellent chemical stability which further

confirmed our hypothesis for the instability of the bisbenzo-

pyran analogues. Both compounds were evaluated in in vitro

assays for their estrogenic and antiestrogenic activity. The

binding affinities of 1a-(() and 8a-(() for ERs were com-

pared to the initial lead compounds. On the basis of the

MCF-7 and Ishikawa cell based functional data, compound

8a-(() seemed to have lost about 10- to 20-fold of antagonist

activity [8a-(() vs 1a-(()]. In immature uterotropic assays,

compound 1a-(() had significantly higher antiuterotropic

inhibition compared to 8-((). On the basis of favorable data

for 1a-((), the racemic compound was resolved and then

evaluated in ERs binding affinity as well as for antagonist

potency in both Ishikawa and MCF-7 cell based functional

assay. Enantiomer 1a-(R) was about 10-fold more potent

than 1a-(S) in both binding and functional assays. In anti-

uterotropic assay, both compounds showed inhibitory activ-

ity. The antiuterotrpic activity of 1a-(R) was significantly

higher than that of 1a-(S) (Table 2).

To examine the SAR of the basic side chain, various ter-

tiary amino groups were incorporated. Replacing piperidine

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7551

Table 2. In Vitro and in Vivo Characterizations of Benzopyranobenzoxapane^a

7552 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Table 2. Continued

Jain et al.

^aAll compounds were tested more than three times in these assays with high reproducibility. The average is shown here. ^bNo agonist activity was found at 10

μM. ^cNo agonist activity was found at 10 μM. ^dInhibitions of estrone-stimulated uterine weight at 1 mg/kg. ^eIn these uterotopic assays, when compounds, or

raloxifene, were administered alone, they showed no significant agonistic activity to stimulate uterine growth except compounds 1b-(R or S), and these effects

were similar to E2 and TAM which is a significant increase in the uterine wet weight (P < 0.005). ^fStimulation in % shown in parentheses. ^gNot determined.

by N,N-dimethylamine or N,N-diisopropylamine did not

alter the binding affinity for ERs but decreased the potency

in MCF-7 and Ishikawa cell based functional assays (1b and

1c vs 1a, Table 2). These compounds also showed poor

antiuterotropic inhibitory activity when tested in antagonist

mode. Interestingly, 1b-(S) and 1c-(S) in uterotropic assays

showed strong stimulatory activity similar to that of tamox-

ifen (Table 2, entries 4 and 6). In cases where piperidine was

replaced by pyrolidine or azapine (1d or 1f), almost all ER

binding affinity was retained while antagonist potency

decreased slightly in Ishikawa and MCF-7 cell based func-

tional assays. The strong inhibitory effect in antiuterotrpic

assay was observed for 1d-(R) and 1d-(S). Both enantiomers

of 1f showed poor inhibitory effects in antiuterotropic assay.

When piperidine ring was replaced by other heterocyclic

rings, such as morpholine and 1-methylpiperazine, the an-

tagonist potency in Ishikawa and MCF-7 cell based func-

tional assays was almost abolished (1f, 1 h vs 1a, Table 2).

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7553

Table 3. In Vitro and in Vivo Characterization of Benzopyranobenzoxapane^a

^aAll compounds were tested more than three times in these assays with high reproducibility. The average is shown here. ^bNo agonist activity was found at

10 μM. ^cNo agonist activity was found at 10 μM. ^dInhibitions of estrone-stimulated uterine weight at 1 mg/kg. ^eIn these uterotopic assays, when compounds,

or raloxifene, were administered alone, they showed no significant agonistic activity to stimulate uterine growth except compounds 3a-(S) and3b-(S), andthese

effects were similar to E2 and TAM which is a significant increase in the uterine wet weight (P < 0.005). ^fStimulation in % shown in parentheses.

These compounds also had poor inhibitory effects in anti-

uterotrpic assay. Compound 1g-(R), where the side chain

contains thiomorpholine, showed very strong inhibitory af-

fect in antiuterotropic assay. We also replaced the side chain

piperidine by a neutral or acidic group that bears hydrogen

bonding acceptors or donors such as pyrrolidine-2,5-dione,

hydroxyl, -COOH, and -COOMe. Such modifications re-

tained most of the binding affinity but had no antagonist

potency in Ishikawa or MCF cell based functional assays.

The length of alkoxy group, OCH₂CH₂-NR₂attached to

E-ring was also extended to one more carbon atom (-OCH₂-

CH₂CH₂-NR₂) to give 1p-(R) as well as 1p-(S); both had

good binding affinity but lost about 100-fold potency in

Ishikawa cell based functional assays. Both compounds had

IC₅₀>1 μM in MCF-7 cell based functional assays.

3d-(R) was comparable to that of 1a-(R) in ER binding

affinity, antagonist potency in MCF-7 and Ishikawa based

functional assays, and inhibitory potency in antiuterotropic

assay. Interestingly, strong stimulatory effect was observed

for compounds 3a-(S) and 3b-(S) where the side chain piper-

idine was replaced by NMe₂and NEt₂. However, the en-

antiomers of this compound, 3a-(R) and 3a-(R), had strong

inhibitory potency in antiuterotropic assays. When hydroxy

group in D-ring was replaced by fluorine atom, the resulting

compounds [3e-(R) and -(S) and 3f-(R) and -(S)] had good

profiles in in vitro assays but weak inhibitory activity in

antiuterotropic assays. Compound 3e-(S) showed no stimu-

latory response in antiuterotropic assay. [3e-(S) vs 3b-(S)].

In Table 4, the SAR was related to D-ring deshydroxy

derivatives. In these cases (R) optical isomers of 4a, 4b, and

4c have about 10-fold better affinity toward ERs. Irrespec-

tive of the side chain, all compounds were weak inhibitors in

antiuterotropic assay.

The alkoxy group attached to E-ring was moved to meta

position. Both 2a-(R) and 2a-(S) had diminished binding

affinity and lost all antagonist potency in MCF-7 and

Ishikawa cell based function assays. All estrogenic activity

was lost when piperidine was replaced by other heterocyclic

rings (2b and 2c vs 2a, Table 2, entries 29-34).

Compounds 1a-(R) and 1a-(S) were converted to di-

methoxy derivatives 7-(S) and 7-(R) as shown in Scheme 5.

Compound 7-(S) had no binding affinity for either ERR or

ERβ receptor. In antiuterotropic assay, poor inhibitory

Table 3 shows the SAR for derivatives where the hydroxy

group in A-ring is either replaced by H or F. Compound

7554 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Table 4. In Vitro and In Vivo Characterization of Benzopyranobenzoxapanes^a

^aAll compounds were tested more than three times in these assays with high reproducibility. The average is shown here. ^bNo agonist activity was

found at 10 μM. ^cNo agonist activity was found at 10 μM. ^dInhibitions of estrone-stimulated uterine weight at 1 mg/kg.

Table 5. In Vitro and in Vivo Characterization of Benzopyranobenzoxapanes^a

ERR binding

IC₅₀(nM)

ERβ binding

IC₅₀(nM)

Ishikawa antag

IC₅₀(nM)^b

MCF-7 antag

IC₅₀(nM)^c

uterotropic activity

inhibition (%)^d

entry

compd

1

2

3

4

5

6

5-(R)

5-(S)

6-(R)

6-(S)

7-(R)

7-(S)

5.8

4.2

99

24

76

150

1210

1236

130

20

99

12

121

7

9

6.3

7

63

259

10

150

25.9

1736

>10000

64

>10000

NA

>10000

^aAll compounds were tested more than three times in these assays with high reproducibility. The average is shown here. ^bNo agonist activity was

found at 10 μM. ^cNo agonist activity was found at 10 μM. ^dInhibitions of estrone-stimulated uterine weight at 1 mg/kg.

Table 6. Single Dose Pharmacokinetics Profiles of SERMs^a

PK parameter (po) 1a-(R) 1g-(R) 4c-(R)

7-(R)

6-(R)

5-(R)

F

_po(%)

C_max(ng/mL)

_max(h)

11

91

9

89

9

30

58

61

168 þ metabolites (5 þ 6 þ 1a)-(R) = 130 219 þ metabolite 1a-(R) = 12 228 þ metabolite 1a-(R) = 14

T

5

4.8

5.28

1528

4.8

5.28

1128

5

6

T_1/2(h)

AUC (ng h/mL)

4.8

1011

7.2

2268

19.8

6918

18.6

6734

3

^aThese compounds were formulated for oral dosing as a uniform suspension in 0.5% methylcellulose vehicle.

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7555

Figure 7. The 6-week osteopenia model: effect of 7-(R) on urine

Dpd.

in in vitro assays as well in antiuterotropic assays and was

selected as a candidate for in depth evaluations.

Figure 5. Effect of 7-(R) on the uterine weight in immature rats.

Pharmacokinetic Results. On the basis of estrogen receptor

(ERR and ERβ) binding affinity, antiestrogenic potency

in MCF-7 and Ishikawa cell-based functional assays, and

inhibitory activity in the uterotropic assay, the lead com-

pounds were selected for evaluation of their pharmacoki-

netic parameters in rats. For pharmacokinetic studies, rats

were dosed intravenously (iv) at doses of 1-3 mg/kg and by

oral gavage at a dose of 10 mg/kg with compounds 1-4.

Compounds were formulated for iv dosing as a solution in

10% β-cyclodextrin, and these compounds were typically

formulated for oral dosing as a uniform suspension in 0.5%

methylcellulose vehicle. Blood samples (0.5 mL) were col-

lected into heparinized tubes postdose via orbital sinus

puncture. Blood samples were centrifuged for cell removal,

and 200 μL of plasma supernatant was transferred to a clean

vial. The plasma samples were prepared in acetonitrile along

with an internal control, analysis was carried out by

LC-MS-MS along with standards, and then pharmacoki-

netic parameters were assessed. The pharmacokinetic pro-

files of compounds 1-4, 12, and 13 are summarized in

Table 6.^9b

Compounds 1a-(R), 1g-(R), and 4c-(R) had poor overall

bioavailability and low exposure to tissues. The moderate

clearance rate indicates that the poor bioavailability may

have been due to poor absorption of these compounds. The

zwitterionic form of the compounds may have further ham-

pered the absorption. Therefore, we decided to cap the

hydroxy group with a methyl group. We were pleased to

observe that compound 7-(R) had good overall bioavailabil-

ity (F_po=30%) with moderate exposure and half-life. We

were also pleased to observe that when 7-(R) was adminis-

tered orally, the potent anti-estrogenic metabolites 5-(R) and

6-(R) were formed along with a small amount of 1a-(R). The

total maximum concentration of these compounds almost

reached 135 ng/mL. When metabolites 5-(R) and 6-(R) were

dosed in pharmacokinetic studies, both metabolites had

Figure 6. Rat 6-week osteopenia model: effect of 7-(R) on uterine

wet weight.

activity was observed. On the other hand, 7-(R) had an IC₅₀

in ERR of about 64 nM but no activity in ERβ receptor

(>100 μM). A strong inhibitory activity was observed for

7-(R) in the antiuterotropic assay. Compounds 1a-(R) and

1a-(S) were also converted into corresponding mono-

methoxy derivatives 5-(R) and 6-(R) or 5-(S) and 6-(S) as

shown in the Scheme 5. Both R and S derivatives of these

monomethoxy derivatives had good profile in the in vitro

assays. However, only 5-(R) and 6-(R) showed strong in-

hibitory activity in the uterotropic assay (Table 5).

In general, compounds with absolute configuration

(R) are significantly more potent in antiuterotropic assays.

Piperidine, thiomorpholine, and azepane are among the

best side chain functional groups for antagonist potency

in Ishikawa and MCF-7 cell based functional assays. Re-

placement of piperideine ring system by dialkyamine,

like -NMe₂, -NEt₂, or ⁱPr₂N-, resulted in strong stimula-

tory activity in antiuterotropic assays. Consistent with lit-

erature observations, -OCH₂CH₂NR₂is the optimal side

chain attached to para position to the aromatic ring. The

basic amine is essential for the antagonist potency in MCF-7

and Ishikawa based functional assays. At least one hydroxy

group in A ring or D ring is required for binding affinity

for ERs. Compound 1a-(R) and its methoxy derivatives,

attached to either A ring or D ring 5-(R) or 6-(R) or

dimethoxy derivative 7-(R) demonstrated excellent profiles

excellent bioavailability (F_po= 58% for 6-(R) and F_po

=

61% for 5-(R)). The overall bioavailability of compound 1a

was only 6% with very low exposure. Part of the reason for

the high bioavailabiilty of monomethoxy derivatives 5-6-(R)

could be electron donating methoxy groups, which reduce

the acidity of the phenolic group, thereby weakening the

zwitterion and improving the absorption.^9b

Pharmacological Results. Recently, we reported that

our phase 2 clinical compound 9-(R) possessed a unique

7556 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Figure 8. Effect of 2 weeks of treatment with metabolites of 7-(R) on bone turnover as assessed by urine Dpd.

Figure 9. Effect of 7-(R) on total bone density (tibia, 6 weeks).

Figure 11. The 2-week adult OVX rat model: effect of 7-(R) on

vaginal fluidity.

flush assay, sesame oil was used as the vehicle. In all cases, the

compound was administered as a suspension. The biological

outcome was compared with two standards, our own devel-

opment compound 9-(R) and raloxifene.^7a,14-17

Adult Ovariectomized Rat Models. The adult ovariecto-

mized estrogen-deficient rat model was applied to evaluate

the tissue selective effects of SERMs. The model is useful

because simultaneous responses in several tissues can be

evaluated. It provided information on ovariectomy-induced

bone loss, plasma lipid levels, and uterine and vaginal effects,

as well as other pathological changes in the cardiovascular

and reproductive systems. The model was used to character-

ize estrogen agonist and antagonist activities of 7-(R). Treat-

ment of test compounds was continued for 2-6 weeks. Bone

density measurements on isolated bones were conducted in

the 6-week model. The effects of these compounds in this

model were in line with the clinical responses in reported

women.^15-17Adult female animals (>6 months old, Charles

River Laboratories, Wilmington, MA) were used. The rats

were housed individually in wire-mesh cages at an ambient

temperature of 21-23 °C with an automated 12 h light/dark

cycle and access to water and a commercial rodent food

ad libitum [we used a casein-based diet to reduce food-

borne estrogens]. Each treatment group consisted of 6-14

animals. The animals were ovariectomized under sterile

conditions and anesthesia. Twenty-four hours after surgery,

compound 7-(R) or metabolites 1a-(R), 5-(R), 6-(R) were

administered daily by oral gavage for 2 or 6 weeks. Other

reference treatment groups included sham-operated con-

trol, ovariectomized controls, and ethynylestradiol treated

(EE, 5 (mg/kg)/day) and raloxifene treated (1 (mg/kg)/day)

Figure 10. The 6-week osteopenia model: effect of 7-(R) on serum

cholesterol.

pharmacological profile as a SERM with a potential for

reduced hot flush and vaginal dryness and an antagonist

effect in breast tissue while maintaining the beneficial effects

of the marketed SERMs raloxifene and tamoxifene.^7aCom-

pound 9 had a shortcoming in that it was a prodrug; the

active metabolite was unstable under ambient conditions.

On the basis of an in vivo, anti-estrogenic assay (for 7-(R), see

Figure 5) and pharmacokinetic data, compound 7-(R) was

evaluated further in several in vivo models of estrogen

activity. The metabolites 1a-(R), 5-(R), and 6-(R) were also

evaluated in some of the studiese. These models were used to

assess the tissue selective activity of the compounds. In these

studies, all compounds were orally administered to animals

in an aqueous homogeneous suspension (in 0.5% Methocel)

once daily for the appropriate treatment time. For the hot

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7557

Figure 12. The 2-week adult OVX rat model: effect of 5-(R) and 6-(R) vaginal fluidity.

groups. Methocel (0.5%) was used as the vehicle for all

compounds including compound 9-(R).

Measurement of Uterine Weight and Uterine Epithelial

Thicknesses. In the above model, animals were euthanized

at the end of the study with CO₂. The uteri were excised,

cleaned of surrounding fat and connective tissue, incised

slightly to release luminal fluid, blotted on filter paper, and

weighed until constant weight. 7-(R) showed modest, dose

dependent effects on uterine weight when administered

alone. The magnitude of this response was comparable to

that seen with 9-(R) and was not significantly different from

raloxifene. In a separate study, the metabolites 5-(R) and

6-(R) as well as 1a-(R) had little or no agonist activity in the

uterus of adult ovariectomized rats following 2 weeks of

Figure 13. Effect of 7-(R) on rat hot flush model.

treatment. There was no significant difference in uterine wet

weight in rats treated with either metabolite compared to

those from vehicle treated animals (Figure 6). Similar effects

are well documented with raloxifene.¹⁶

After the uterine tissue was weighed, it was fixed in

formalin to prepare it for immunohistochemical analysis

and the uterine epithelial thickness was measured as de-

scribed by Clark et al.^15a,15bThe uterine epithelial thick-

nesses is a very sensitive gauge of estrogenic activity in

uterous.¹⁵The activity in this model was compared to that

of 9-(R) and raloxifene (Figure 14).

Histomorphometric measurement of rat uterine epithe-

lium showed that estrone, known to induce endometrial

hyperplasia and neoplasm, stimulated epithelium prolifera-

tion and caused increase of epithelial thickness after 6 weeks

of treatment. The epithelial thickness in rats treated with

estrone at 0.1 (mg/kg)/day was significantly higher than

those from all other treatment groups (p < 0.05). The effect

of 7-(R) on the epithelium was similar to that of raloxifene.

That is, there was a minor increase in epithelial thickness

in animals treated with raloxifene (1 (mg/kg)/day) and 7-(R)

(at 0.001, 0.03, and 0.3 (mg/kg)/day). No difference was

found between raloxifene at 1 (mg/kg)/day and 7-(R) at all

doses. There was also no difference between 7-(R) at the three

doses. These results along with uterine weight suggest that

that compound 7-(R) does not stimulate uterine tissue.

(Figure 14). Similar observations were also found for com-

pounds 5-(R) and 6-(R).^9b

Bone Turnover. Urine deoxypyridinoline (Dpd) is a sensi-

tive biomarker for bone resorption. Ovariectomy in female

rats causes depletion of endogenous estrogen, which leads to

an increase in bone resorption. This subsequently causes

bone loss, which mimics the situation in postmenopausal

women. In this model, urine Dpd increased significantly in

OVX ovariectomized control animals compared to sham

Figure 14. Effect of 7-(R) on uterine epithelial thickness after 6

weeks of treatment.

operated animals after 2 weeks of treatment (Figure 7).¹⁷

Compound 9-(R) (1.4 mg/kg) and raloxifene suppressed the

urine Dpd level as expected. All other parameters in these

animals responded as predicted to EE treatment. 7-(R) was

very potent in its ability to lower urine Dpd levels. The effect

was statistically significant at a dose of 0.3 mg/kg, and a

trend toward decreased Dpd levels at lower doses for low-

ering of urine Dpd levels was also found. The metabolites

5-(R), 6-(R), and 1a-(R) were effective at lowering bone

turnover, as measured by urine Dpd levels, in rats following

2 weeks of treatment (Figure 8). In general, 7-(R) was more

potent than its metabolite 5-(R) and 6-(R). On the basis of the

effect of 7-(R) on Dpd levels, bone mineral density was also

measured for 7-(R). For the measurement of bone mineral

density, the left tibia was removed from the animal, cleaned,

and fixed in 10% formalin. Ex vivo peripheral quantitative

7558 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Table 7. Summary of in Vivo Efficacy Studies for 7-(R)

7-(R)

9-(R)

ethinyl estradiol

agonist

raloxifene

antagonist

immature rat uterotropic test

result for adult ovariectomized rat model

antagonist

uterus

serum cholesterol

bone

antagonist

agonist

antagonist

agonist

antagonist

agonist

hot flush

vagina

antagonist

computerized tomography (pQCT) was conducted, and

trabecular and cortical bone mineral density and bone

mineral content measurements were carried out using a

XCT_960A pQCT system (Norland Medical Systems, Fort

Atkinson, WI) on the proximal tibial metaphysis at 5 and

6 mm distal to the knee joint. A voxel size of 0.148 mm and a

threshold of 0.600 cm for cancellous bone were used. In-

creasing doses of 7-(R), from 0.003 to 0.3 (mg/kg)/day, were

orally administered to ovariectomized rats for 6 weeks,

and the density of tibial bone was measured. 7-(R) effec-

tively prevented bone loss in a dose-dependent manner. At

0.3 (mg/kg)/day, 7-(R) prevented the loss of total bone

density caused by ovariectomy (Figure 9). These effects were

comparable to those seen with higher dose of raloxifene.^16,17

Measurement of Serum Total Cholesterol Levels. The

compound 7-(R) was evaluated for the ability to reduce

overall cholesterol levels. Blood samples were collected

orbitally after 2 or 6 weeks of treatment. Serum samples

were analyzed using a Roche Hitachi 717 chemistry analyzer

at LabCorp. The effect of 7-(R) on serum total cholesterol

was similar in the 6-week treated animals to that seen in

animals treated for 2 weeks. Plasma cholesterol levels were

reduced approximately 60% after 6 weeks of treatment

(Figure 10). The metabolites 5-(R) and 6-(R) were both

effective at lowering plasma total cholesterol levels in rats

following 2 weeks of treatment. 7-(R) lowered plasma cho-

lesterol about 50% at both 0.0.03 and 0.3 mg/kg.^9b

Measurement of Weight of Vaginal Fluid. Compound 7-(R)

was evaluated in the rat vaginal fluidity model to assess its

activity in the vagina. The fluid in vagina was collected using

a cotton swab, and the absolute weight of the fluid was

measured from each animal after 2 or 6 weeks of treatment.

Estrogen and 5 showed the expected increase in vaginal fluidity

(Figure 11). 7-(R) increased the weight of vaginal fluid in OVX

rats in a dose dependent manner. At the 0.1 mg/kg dose, the

effect was similar to or better than that seen with 1.4 mg/kg of

5 or 0.1 mg of EE at the end of 6 weeks. Compound 5-(R) was

very effective at increasing vaginal secretions. This metabolite

showed increased vaginal fluidity significantly at 1.0 mg/kg

(Figure 12). In contrast, 6-(R) and raloxifene were not effective

at increasing vaginal fluidity.

MA) were used for this assay. Each treatment group con-

sisted of 8-25 animals. They were housed individually in

wire-mesh cages at an ambient temperature of 21-23 °C with

an automated 12 h light/dark cycle and access to water and

commercial rodent food ad libitum. The rats were ovariec-

tomized under anesthesia. Six days after ovariectomy, treat-

ment of the rats was initiated. Compound 9-(R) or raloxifene

was administered orally by gavage. The rats were injected

subcutaneously (sc) with a suspension containing 75 and

150 mg of morphine (freebase) on days 3 and 5 of treatment,

respectively. On the last day of treatment, the animals were

lightly anesthetized with ketamine (80 mg/kg, intramuscular).

Following anesthesia, a thermistor (YSI 400 series, YSI Pre-

cision Temperature Group, Dayton, OH), connected to a data

acquisition system (Acquisition Interface model ACQ-10,

Gould 6600 Amplifier, Gould Instrument System Inc., Valley

View, OH), was placed on the tail of the animals. Following

measurement of the baseline tail skin temperature for about

20 min, naloxone (2.0 mg/kg, sc, Sigma, St. Louis, MO) was

administered to induce morphine withdrawal. Tail skin tem-

perature was then measured for an additional 60 min. Multiple

comparisons among the treatment groups at each time point

were used for analysis. The values of area under curve (AUC)

from the first 15 min following morphine withdrawal and

maximal temperature change (ΔT) are reported here.^9bOur

data demonstrate that 7-(R) was able to reduce the rise in tail

skin temperature to an extent similar to that seen with 9-(R)

and EE (Figure 13). This unique pharmacological profile

makes compound 7-(R) an ideal clinical candidate for the

treatment of hot flush.

Conclusion

We have discovered benzo[b]pyranobenzo[b]oxapines and

benzopyranobenzo[b]oxocine as novel SERMs. Numerous

derivatives of were prepared and evaluated for their biological

activity as SERMs. In general, compounds with absolute

configuration (R) are significantly more potent in antiutero-

tropic assays. Piperidine, thiomorpholine, and azepane are

among the best side chain functional groups for antagonist

potency in Ishikawa and MCF-7 cell based functional assays.

Replacement of piperideine ring system by dialkyamine, like

-NMe₂or -NEt₂resulted in strong stimulatory activity in

antiuterotropic assays. Consistent with literature observa-

tions, -OCH₂CH₂NR₂is the optimal side chain attached to

para position to the aromatic ring. The basic amine is essential

for the antagonist potency in MCF-7 and Ishikawa based

functional assays. At least one hydroxy group in A ring or

D ring is required for binding affinity for ERs. Compound

1a-(R) and its methoxy derivatives, attached to either A ring

or D ring, or dimethoxy derivatives 5-(R) and 6-(R) demon-

strated excellent profiles in in vitro assays as well in antiuter-

otropic assays, and 1a-(R) was selected as a candidate for

in depth evaluations. Data from in vivo studies demonstrated

Activity in the Rat Hot Flush Model. One of the important

activities of an “ideal SERM” compound is the ability to

reduce the incidence and severity of the hot flush, a symptom

that frequently occurs in postmenopausal women. In the

ovariectomized rat hot flush model, morphine-addicted rats

undergo morphine withdrawal, after which they experience a

“hot flush” that can be measured by their tail skin tempera-

ture. Estrogens have been shown to block this hot flush.

This model has been used to characterize several SERMs

including raloxifene and bazedoxifene. The effects of these

compounds in this model have been predictive of clinical

responses in women.¹⁸Adult female Sprague-Dawley rats

(3 months old, Charles River Laboratories, Wilmington,

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7559

that 7-(R) possesses an “ideal SERM profile” in animal

studies and is an excellent backup candidate to our clinical

candidate 9-(R). It not only exhibits estrogen agonist effects

on bone and lipid and antagonistic effects on mammary

glands and uterus but also alleviates hot flush and increa-

ses vaginal lubrication. Full efficacy was achieved at the

0.3 mg/kg dose. This unique pharmacological profile makes

compound 7-(R) an ideal clinical candidate for the treat-

ment of hot flush and vaginal dryness in postmenopausal

women, without the risk of uterine or breast cell stimulation

(Table 7).

and then brine. The organic layer was combined and dried over

sodium sulfate. After removal of the solvent, the crude product

was purified on HPLC. Purity: 97% by HPLC. LC-MS:

R_f=3.791 min. MS m/z 500 (M þ 1), 522 (M þ 23). ¹H NMR

(CD₃OD) δ 1.49 (broad s, 2H), 1.69 (broad s, 4H), 1.91 (broad

m, 2H), 2.08 (broad m, 2H), 2.71 (broad m, 4H), 2.92 (broad m,

2H), 3.74 (broad s, 1H), 4.12 (broad m, 2H), 4.56 (broad s, 1H),

5.95 (s, 1H), 6.08-7.65 (m, 10H). HRMS, m/z calcd for

C₃₁H₃₄NO₅(M þ H^þ) 500.2437, found 500.2439. Anal. Calcd

for C₃₁H₃₅NO₆(M þ H₂O): C, 71.93; H, 6.82; N, 2.71; O, 18.55.

Found: C, 71.92; H, 6.79; N, 2.69.

Preparation of 5-[4-(2-Dimethylaminoethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-

2,8-diol, 1b. To a solution of 4.64 g of 1-[2-(4-iodophenoxy)-

ethyl]dimethylamine (15.95 mmol) in 40 mL of THF at

-78 °C was added dropwise 6.38 mL of n-butyllithium (2.5 M

in hexane). The solution was stirred at -78 °C for 30 min before

the solution of lactal (14a) (2.8 g, 5.32 mmol) in 10 mL THF was

added slowly, stirred for another 30 min after the addition, and

quenched with aqueous ammonium chlorideandextracted with

ethyl acetate. The organic layer was combined and dried over

sodium sulfate. After removal of the solvent the crude product

was dissolved in 200 mL of toluene, and 1.64 mL of TFA was

added. The solution was stirred for 1 h, neutralized with 5%

NaHCO₃, and extracted with ethyl acetate. The organic layer

was combined and dried over sodium sulfate. The crude product

was dissolved in 50 mL of acetonitrile, and an amount of 5 mL of

70% HF in pyridine was added at room temperature. The

reaction mixture was stirred overnight and diluted with ethyl

acetate and washed with 5% NaHCO₃, then brine. The organic

layer was dried over sodium sulfate and concentrated. The crude

product was purified with flash column chromatography and

eluted with 5% methanol in dichloromethane. Purity, 97% by

HPLC. LC-MS: R_f=1.98. MS: m/z, 446 (M þ 1), 468 (M þ 23).

¹H NMR (CD₃OD, 400 MHz) δ (ppm) 7.4 (d, J=8.4 Hz, 2H),

7.15 (d, J=8.4 Hz, 1H), 7.02 (d, J=8.4 Hz, 1H), 6.85 (d, J=

8.4 Hz, 2H), 6.5 (m, 2H), 6.35 (dd, ¹J=8.4 Hz, ²J=2 Hz, 1H),

6.15 (d, J=2 Hz, 1H), 6.05 (s, 1H), 4.6 (m, 2H), 4.25 (t, J=4 Hz,

2H), 3.5 (t, J = 4 Hz, 2H), 3.3 (m, 2H), 2.9 (s, 6H). HRMS,

m/z calcd for C₂₇H₂₇NO₅(M^þ) 445.5070, found 445.5997.

The racemic compound 1b was loaded onto a ChiralPak AD

chiral HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with

80% IPA and 20% hexanes at the 150 mL/min flow rate. The

two peaks were collected to yield the two enantiomers as follows:

1b-(R) as peak 1, [R] þ66° (c 0.402, MeOH); 1b-(S) as peak 2,

[R] -65° (c 0.5, MeOH).

Experimental Section

General Information. Optical rotations were measured on a

Perkin-Elmer model 341 polarimeter. ¹H and ¹³C spectra were

measured on a Bruker 300, 400, or 500 MHz instrument. In the

case of ¹³C spectra, these measurements were taken with full

proton decoupling. Data for proton spectra are reported as

follows: chemical shifts, reported in ppm and utilizing the

residual solvent as an internal standard, integration, multiplicity

(s=singlet, d=doublet, t=triplet, q=quartet, nd=narrow

doublet), coupling constants (Hz). Analytical high performance

liquid chromatography (HPLC) coupled with MS and UV

diodray detectors was performed on an Agilent 1100 series

instrument at 280 nm (UV detector) and mass ranging from

300 to 1000 (MS detector) using the following: (a) Phenonme-

nex, Luna 5 μm, phenylhexyl 150 mm ꢀ 4.60 mm; solvent A,

H₂O (0.1% TFA); solvent B, CH₃CN (0.1% TFA); gradient

20-90% of solvent A to B; flow rate, 1 mL/min; total run time,

15 min. (b) Phenonmenex, Luna 5 μm, 150 mm ꢀ 4.60 mm;

solvent A, H₂O (0.1% TFA); solvent B, CH₃CN (0.1% TFA);

gradient, 20-90% of solvent A to B; flow rate, 1 mL/min; total

run time, 15 min. (c) YMC diol 120, 100 mm ꢀ 4.6 mm (achiral,

normal phase) column; solvent system 50% IPA in hexanes,

isocratic solvent sytem; flow rate, 1 min/mL; run time, 20 min.

(d) Diacel ChiralPak AD 250 mm ꢀ 4.6 mm (chiral) column

using an isocratic solvent mixture, 50:50 IPA/hexanes, at a flow

rate of 1 mL/min.

For thin layer chromatography (TLC) analysis throughout

this work, Analtech Uniplate precoated plates were used in

conjunction with a variety of developing reagents including

phosphomolybdic acid (PMA) and para-anisaldehyde (PAA)

in addition to UV light. Purification of materials was carried out

using an ISCO chromatography system with prepacked silica gel

columns. High-resolution mass spectrometry (HRMS) was

performed by M-Scan, Inc., and elemental analyses were per-

formed by QTI Technologies. All reagents and solvents were

used as received from commercial source.

The following compounds were prepared using Scheme 2.

Synthesis of Compound 8a. [2-(4-Iodo-phenoxy)ethyl]piperi-

dine (1.5 g, 4.5 mmol) was dissolved in 10 mL of THF and cooled

to -78 °C. To the solution was added dropwise 1.8 mL of

n-butyllithium (2.5 M in hexane). The solution was stirred

at -78 °C for 30 min before the addition of 0.82 g (1.5 mmol)

of lactal, 14 g (X2 = X1 = OTBS, n = 3)⁸in 5 mL of THF,

stirred for another 30 min after the addition, quenched with

aqueous ammonium chloride, extracted with ethyl acetate,

and the organic layer was combined and dried over sodium

sulfate.

Preparation of 5-[4-(2-Diisopropylaminoethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-

diol, 1c. Following the procedure described for 1b, lactal 14a (1.5 g,

2.85 mmol) was reacted in sequence with [2-(4-iodophenox-

y)ethyl]diisopropylamine HCl and then HF Py to yield 1.1 g of

3

the title compound as a pink solid. Purity 97%. LC-MS: R_f=

2.4. MS (m/z): MH^þ(502), MH^-(500). ¹H NMR (CDOD₃) δ 1.28

(d, 12H, J=5.3 Hz), 2.78 (m, 2H), 3.25 (m, 2H), 3.52 (m, 2H), 4.05

(m, 2H), 4.56 (m, 2H), 6.05-7.35 (m, 11H). HRMS, m/z calcd for

C₃₁H₃₅NO₅(M^þ) 501.2515, found 501.2515. Anal. Calcd: C,

74.23; H, 7.03; N, 2.79; O, 15.95. Found: C, 74.19; H, 7.04; N, 2.78.

The racemic 5-[4-(2-diisopropylaminoethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-

2,8-diol compound (1.4 g) was loaded onto a ChiralPak AD

chiral HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with

80% IPA and 20% hexanes at the 150 mL/min flow rate. The

two peaks were collected to yield the two enantiomers as

follows. Peak 1: 5R-(þ)-[4-(2-diisopropylaminoethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 1c-(R). [R]_Dþ43 (c 0.112, MeOH). MS (m/z): MH^þ

(502), MH^-(500). Peak 2: 5S-(-)-[4-(2-diisopropylamino-

ethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta-

[1,2-a]naphthalene-2,8-diol, 1c-(S). [R]_D-69 (c 0.812, MeOH). MS

(m/z): MH^þ(502), MH^-(500).

After removal of the solvent, the crude product was dissolved

in 15 mL of toluene and was cooled to 0 °C. HCl (36.5%, 0.5 mL)

was added dropwise. The reaction mixture was stirred at 0 °C for

1 h. The mixture was diluted with ethyl acetate and washed with

5% NaHCO₃, then brine. The organic layer was dried over

sodium sulfate and concentrated. The crude product was dis-

solved in 15 mL of THF, and 3.75 mL of 1.0 M TBAF in THF

was added. The reaction mixture was stirred for 1 h, diluted with

ethyl acetate, and washed with aqueous ammonium chloride

7560 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Preparation of 5-[4-(2-Azepan-1-ylethoxy)phenyl]-11,12-dihy-

dro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-

diol, 1d. Following the procedure as described for 1b, lactal 14a

(1.5 g,2.85 mmol) was reacted in sequence with 1-[2-(4-iodophe-

(d, J=8.4 Hz, 2H), 6.45 (m, 2H), 6.3 (d, ¹J=8.4 Hz, ²J=2 Hz,

1H), 6.12 (d, J=2 Hz, 1H), 6.1 (s, 1H), 4.55 (m, 2H), 4.0 (t, J=

8.4 Hz, 2H), 2.9 (m, 8H), 2.7 (m, 2H), 2.6 (t, J=8.4 Hz, 2H).

HRMS, m/z calcd for C₂₉H₃₀NO₆(M þ H^þ) 488.2073, found

488.2079. The racemic compound 1f (0.9 g) was loaded onto a

ChiralPak AD chiral HPLC column (5 cm i.d. ꢀ 50 cm length)

and eluted with 80% IPA and 20% hexanes at the 150 mL/min

flow rate. The two peaks were collected to yield the two

enantiomers as follows: 1f-(R) as peak 1, [R] þ27° (c 0.304,

MeOH); 1f-(S) as peak two, [R] -28° (c 0.41, MeOH).

noxy)ethyl]azepane, HCl, and then HF Py to yield 1.1 g of the

title compound (1d) as a light-yellow solid. Purity: 95% by LC-

3

1

MS, R_f=2.13. MS (m/z): MH^þ(500), MH^-(498). H NMR

(CDOD₃) δ 1.65 (m, 4H), 1.84 (m, 4H), 2.78 (m, 2H), 3.35 (m,

4H), 3.48 (m, 2H), 4.18 (m, 2H), 4.61 (m, 2H), 6.02 (s, 1H), 6.18-

7.35 (m, 10 H). HRMS, m/z calcd for C₃₁H₃₄NO₅(M þ H^þ),

exact mass 500.2437, found 500.2444.

Preparation of 5-[4-(2-Pyrrolidin-1-ylethoxy)phenyl]-11,12-di-

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-

2,8-diol, 1e. To a solution of 1.9 g of 1-[2-(4-iodophenoxy)-

ethyl]pyrrolidine (6.0 mmol) in 20 mL of THF at -78 °C was

added dropwise 2.5 mL of n-butyllithium (2.5 M in hexane). The

solution was stirred at -78 °C for 30 min before a solution of

1.05 g of lactal 14a (2.0 mmol) in 5 mL of THF was added slowly.

The reaction mixture was stirred for another 30 min after the

addition and then quenched with aqueous ammonium chloride

and extracted with ethyl acetate. The organic layer was com-

bined and dried over sodium sulfate. After removal of the

solvent the crude product was dissolved in 100 mL of toluene,

and 0.67 mL of 36.5% HCl was added. The solution was stirred

for 1 h and neutralized with 5% NaHCO₃and extracted with

ethyl acetate. The organic layer was dried over sodium sulfate.

After removal of the solvent, the crude product was dissolved in

20 mL of acetonitrile and 1 mL of 70% HF in pyridine was

added at room temperature. The reaction mixture was stirred

overnight and diluted with ethyl acetate and washed with 5%

NaHCO₃, then brine. The organic layer was dried over sodium

sulfate and concentrated. The crude product was purified with

flash column chromatography and eluted with 5% methanol in

dichloromethane. Then 0.90 g of slightly yellow solid was

yielded (95% pure). LC-MS: R_f=2.701 min, >97%, m/z 472

The racemic compound 5-[4-(2-azepan-1-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol (1d) (1.1 g) was loaded onto a ChiralPak AD chiral

HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with 50% IPA

and 50% hexanes at the 200 mL/min flow rate. The two peaks were

recollected to yield the two enantiomers as follows: Peak 1: 1d-(R).

[R]_Dþ 33 (c 0.11, MeOH). MS (m/z): MH^þ(500), MH^-(498).

Peak 2: 5S-(-)-[4-(2-azepan-1-ylethoxy)phenyl]-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-diol, 1d-(S).

[R]_D-39 (c 0.51, MeOH). MS (m/z): MH^þ(500), MH^-(498).

Preparation of [4-(2-Piperidin-1-ylethoxy)phenyl]-11,12-dihy-

dro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-

diol, 1a. Following the procedure as described for 1b, lactal 14a

(1.5 g,2.85 mmol) was reacted in sequence with 1-[2-(4-iodophe-

noxy)ethyl]azepane, HCl, and then HF Py to yield 1.2 g of the

3

title compound 1a (96% pure by HPLC). The racemic com-

pound 1a (1.1 g) was loaded onto a ChiralPak AD chiral HPLC

column (5 cm i.d. ꢀ 50 cm length) and eluted with 80% IPA and

20% hexanes at the 150 mL/min flow rate. The two peaks were

collected to yield the two enantiomers as follows. Peak 1:

5R-(þ)-[4-(2-piperidin-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-

1

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-diol, 1a-(R). H

NMR (CD₃OD) δ 1.46 (m, 2H), 1.59 (m, 4H), 2.55 (m, 4H),

2.72 (M, 2H), 2.81 (m, 2H), 4.02 (t, 2H, J=5.4 Hz). 4.60 (m, 2H),

6.05 (s, 1H), 6.14-7.34 (m, 10H). Mp 147-149 °C. [R] þ57° (c=

(M

þ

1). ¹H NMR (CD₃OD)

δ 1.46 (m, 2H), 1.54

(m, 2H), 2.55 (m, 4H), 2.72 (M, 2H), 2.79 (m, 2H), 4.04 (t, 2H,

J =5.4 Hz). 4.60 (m, 2H), 6.15 (s, 1H), 6.14-7.34 (m, 10H).

HRMS, m/z calcd for C₂₉H₃₀NO₅472.2124, found 472.2119.

The

racemic compound 1e (0.9 g) was loaded onto a ChiralPak AD

chiral HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with

80% IPA and 20% hexanes at the 150 mL/min flow rate. The

two peaks were collected to yield the two enantiomers as follows:

1e-(R) as peak 1, [R] þ29° (c 0.41, MeOH); 1e-(S) as peak 2, [R] -

31° (c 0.21, MeOH).

Preparation of 5-[4-(2-Piperidin-1-ylethoxy)phenyl]-11,12-di-

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol,

3d. Following the procedure described for 2b, lactal 14b was

reacted with 1-[2-(4-iodophenoxy)ethyl]piperidine (Scheme 2,

X₂= H, Y₂= OTBS, NR₂= -NC₅H₁₀^c) to yield 2-(8-(tert-

butyldimethylsilanyloxy)-5-{hydroxy-[4-(2-piperidin-1-ylethoxy)-

phenyl]methyl}-2,3-dihydrobenzo[b]oxepin-4-yl)phenol 16d, which

was then treated with HCl (12 N, 4 equiv, 0.67 mL) in toluene

(100 mL) to yield 1-(2-{4-[2-(tert-butyldimethylsilanyloxy)-11,

12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-

yl]phenoxy}ethyl)piperidine as a crude oil. The crude unsubstituted

0.302, MeOH). Anal. Calcd for C₃₀H₃₁NO₅0.95H₂O: C, 71.68; H,

3

6.60; N, 2.79. Found: C, 71.67; H, 6.52; N, 2.57. MS (m/z): MH^þ

(486). Peak 2: 5S-(-)-[4-(2-piperidin-1-ylethoxy)phenyl]-11,12-di-

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-

2,8-diol, 1a-(S). [R] -59° (c 0.41, MeOH). MS (m/z): MH^þ(486).

HRMS, m/z calcd for C₃₀H₃₂NO₅(M þ H^þ) 486.5788, found

486.5783. Anal. Calcd for C₃₁H₃₅NO₆(M þ MeOH): C, 71.93; H,

6.82; N, 2.71; O, 18.55. Found: C, 71.92; H, 6.81; N, 2.72.

Preparation of 5-[4-(2-Morpholin-4-ylethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-

2,8-diol, 1f. To a solution of 2.0 g of 1-[2-(4-iodophenoxy)-

ethyl]piperidine (6.1 mmol) in 20 mL of THF at -78 °C was

added dropwise 2.5 mL of n-butyllithium (2.5 M in hexane). The

solution was stirred at -78 °C for 30 min before a solution of

1.05 g of lactal 14a (2.0 mmol) in 5 mL of THF was added slowly,

stirred for another 30 min after the addition, quenched with

aqueous ammonium chloride, and extracted with ethyl acetate.

The organic layer was combined and dried over sodium sulfate.

After removal of the solvent, the crude product was dissolved in

100 mL of toluene, and 0.67 mL of 36.5% HCl was added. The

solution was stirred for 1 h and neutralized with 5% NaHCO₃

and extracted with ethyl acetate. The organic layer was com-

bined and dried over sodium sulfate. After concentration, the

crude product was dissolved in 20 mL of acetonitrile, and 1 mL

of 70% HF in pyridine was added at room temperature. The

reaction mixture was stirred overnight and diluted with ethyl

acetate and washed with 5% NaHCO₃, then brine. The organic

layer was dried over sodium sulfate and concentrated. The crude

product was purified with flash column chromatography

and eluted with 5% methanol in dichloromethane. A slightly

yellow solid was yielded (0.90 g, 92%). Purity: 97% by LC-MS,

piperidine was then treated with HF pyridine (70% HF, 30% Py,

3

0.5 mL) in CH₃CN (20 mL) at room temperature for 30 min. The

reaction mixture was diluted with ethyl acetate/THF (1:1) and then

washed with 5% NaHCO₃and brine. The reaction mixture was

dried, concentrated, and purified by flash chromatography and

eluted with 5% MeOH in DCM to yield the title compound as a

slightly yellow solid. Purity 95% by LC-MS, R_f=2.1. MS (m/z):

MH^þ(470). ¹H NMR (acetone-d₆) δ 1.35 (m, 2H), 1.49 (m, 4H),

2.42 (br s, 4H), 2.64 (m, 2H), 2.71-2.98 (m, 3H), 3.91 (m, 2H),

1

4.59-4.74 (m, 2H), 6.21 (s, 1H), 6.55-7.45 (m, 11H). H NMR

(DMSO-d₆) δ 1.36 (m, 6H), 2.28-2.59 (m, 6H), 2.65 (m, 1H), 2.89

(m, 1H), 3.91 (t, 2H, J=6.6 Hz), 4.59 (m, 2H), 6.16-7.38 (m, 12H),

9.65 (s, 1H). HRMS, m/z calcd for C₃₀H₃₁NO₄469.2253, found

469.2249.

1

R_f= 2.682 min. MS m/z 488 (M þ 1). H NMR (DMSO-d₆,

400 MHz) δ (ppm) 9.7 (bs, 1H), 9.55 (bs, 1H), 7.3 (d, J =

8.4 Hz, 2H), 7.2 (d, J=8.4 Hz, 1H), 7.05 (d, J=8.4 Hz, 1H), 6.8

Article

The racemic 5-[4-(2-piperidin-1-ylethoxy)phenyl]-11,12-di-

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7561

2-ol compound (1.1 g) was loaded onto a ChiralPak AD chiral

HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with 20%

MeOH and 80% IPA at the 150 mL/min flow rate. The two

peaks were collected to yield the enantiomers as follows. Peak 1:

5R-(þ)-[4-(2-diethylaminoethoxy)phenyl]-11,12-dihydro-5H-6,13-

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3b-(R). [R]_Dþ42

(c 0.3, MeOH). MS (m/z): MH^þ(458). Peak 2: 5S-(-)-[4-(2-

diethylaminoethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo-

[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3b-(S). [R]_D-41 (c 0.31,

MeOH). MS (m/z): MH^þ(458).

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-

ol 3d compound (800 mg) was loaded onto a ChiralPak

AD chiral HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted

with 100% IPA at the 150 mL/min flow rate. The two peaks

were collected to yield the enantiomers as follows. Peak 1:

5R-[4-(2-piperidin-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol as 3d-(R). MS

(m/z): MH^þ(470). [R]_Dþ39 (c 0.23, MeOH). Peak 2: 5S-(þ)-

[4-(2-piperidin-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxa-

benzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3d-(S). MS (m/z):

MH^þ(470). [R]_D-37 (c 0.43, MeOH).

Preparation of 5-[4-(2-Azepan-1-ylethoxy)phenyl]-8-fluoro-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-

2-ol, 3f. The title compound was prepared according to the

procedure described for 1b starting from lactal 14d (1.1 g).

Preparation of 5-[4-(2-Azepan-1-ylethoxy)phenyl]-11,12-dihy-

dro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol,

3c. Followingthe procedure describedfor 1b, the lactal14 (1.89g,

2.0 mmol) was reacted with 1-[2-(4-Iodophenoxy)ethyl]azepane

to yield 950 mg of the title compound 3c as a yellow solid. Purity

1

Purity 97% by LC-MS. MS (m/z): M þ H=501. H NMR

(CDCl₃) δ 1.61 (m, 8H), 2.71-2.99 (m, 8H), 3.92 (t, 2H, J=6.6

Hz), 4.66 (m, 2H), 6.08 (s, 1H), 6.46-7.36 (m, 10H). HRMS m/z

calcd for C₃₁H₃₂FNO₄501.2315, found 501.2326. The racemic

5-[4-(2-azepan-1-ylethoxy)phenyl]-8-fluoro-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol compound

3f (700 mg) was loaded onto a ChiralPak AD chiral HPLC

column (5 cm i.d. ꢀ 50 cm length) and eluted with 80% IPA and

20% hexanes at the 150 mL/min flow rate. The two peaks were

collected to yield the two enantiomers as follows. Peak 1:

5R-(þ)-[4-(2-azepan-1-ylethoxy)phenyl]-8-fluoro-11,12-dihydro-

5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3f-(R).

[R]_Dþ24.2 (c 0.305, MeOH). MS (m/z): M þ H=501. Peak 2:

5S-(-)-[4-(2-azepan-1-ylethoxy)phenyl]-8-fluoro-11,12-dihydro-

5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3f-(S).

[R]_D-28.2 (c 0.5, MeOH). MS (m/z): M þ H=501.

1

97% by LC-MS, R_f= 3.1. MS (m/z): MH^þ(484). H NMR

(acetone-d₆) δ 1.54 (m, 8H), 2.58-2.95 (m, 8H), 3.95 (m, 2H),

4.59-4.74 (m, 2H), 6.21 (s, 1H), 6.51-7.45 (m, 11H). ¹H NMR

(DMSO-d₆) δ 1.51 (broad s, 8H), 2.45 (broad m, 4H), 2.70 (broad

m, 2H), 3.22 (broad s, 2H), 3.91 (t, 2H, J=6.6 Hz), 4.56 (m, 2H),

6.15 (s, 1H), 6.39-7.36 (m, 11H), 9.67 (s, 1H). HRMS m/z calcd

for C₃₁H₃₃NO₄(M^þ) 483.2410, found 483.2415. The racemic

5-[4-(2-azepan-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxa-

benzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol compound (950 mg)

was loaded onto a ChiralPak AD chiral HPLC column (5 cm

i.d. ꢀ 50 cm length) and eluted with 100% IPA at the 150 mL/min

flow rate. The two peaks werecollected to yield the enantiomersas

follows. Peak 2: 5S-(-)-[4-(2-azepan-1-ylethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-

ol, 3c-(S). [R]_D-28 (c 0.12, MeOH). MS (m/z): MH^þ(484).

Peak 1: 5R-(þ)-[4-(2-azepan-1-ylethoxy)phenyl]-11,12-dihydro-

5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3c-(R).

[R]_Dþ38 (c 0.25, MeOH). MH^þ(484).

Preparation of 5-[4-(2-Dimethylaminoethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-8-

ol, 4a. Following the same three-step sequence described for

preparation of 1b, lactal 14c was reacted in sequence with [2-(4-

Iodophenoxy)ethyl]dimethylamine HCl and then HF Py to

3

Preparation of 5-[4-(2-Dimethylaminoethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-

ol, 3a. Following the procedure described for 1b, lactal 14b

was reacted in sequence with [2-(4-iodophenoxy)ethyl]di-

methylamine HCl and then HF Py to yield the title compound

yield the title compound 4a as a brown solid. Purity 97%. MS

(m/z): MH^þ(430). ¹H NMR (DMSO-d₆) δ 2.12 (s, 6H), 2.49-

2.90 (m, 4H), 3.95 (t, 2H, J=6.6 Hz), 4.61 (m, 2H), 6.09-7.23

(m, 11H), 9.54 (s, 1H). HRMS m/z calcd for C₂₇H₂₈NO₄(M þ

H^þ) 430.2018, found 430.1998.

3

as a yellow solid. Purity 96% by LC-MS, R_f=2.93. MS (m/z):

MH^þ(430). ¹H NMR (CDCl₃) δ 2.28 (s, 6H), 2.72 (m, 2H), 2.82

(m, 2H), 3.95 (m, 2H), 4.59 (m, 2H), 6.02 (s, 1H), 6.41-7.29 (m,

11H). ¹H NMR (DMSO-d₆) δ 2.13 (s, 6H), 2.43-2.92 (m, 4H),

3.95 (t, 2H, J=6.6 Hz), 4.59 (m, 2H), 6.15 (s, 1H), 6.38-7.39 (m,

11H), 9.69 (s, 1H). HRMS m/z calcd for C₂₇H₂₈NO₄(M þ H^þ)

430.2018, found 430.1998.

The racemic 5-[4-(2-dimethylaminoethoxy)phenyl]-11,12-di-

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-8-

ol, 4a (800 mg), was loaded onto a ChiralPak AD chiral HPLC

column (5 cm i.d. ꢀ 50 cm length) and eluted with 100% IPA at

the 150 mL/min flow rate. The two peaks were collected to yield

the two enantiomers as follows. Peak 1: 5R-(þ)-[4-(2-dime-

thylaminoethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo-

[3,4]cyclohepta[1,2-a]naphthalen-8-ol, 4a-(R). [R]_Dþ42 (c 0.34,

MeOH). MS (m/z): MH^þ(430). Peak 2: 5S-(-)-[4-(2-dime-

thylaminoethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo-

[3,4]cyclohepta[1,2-a]naphthalen-8-ol, 4a-(S). [R]_D-42 (c 0.34,

MeOH). MS (m/z): MH^þ(430).

The racemic 5-[4-(2-dimethylaminoethoxy)phenyl]-11,12-di-

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-

ol compound (890 mg) was loaded onto a ChiralPak AD chiral

HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with 20%

MeOH and 80% IPA at the 150 mL/min flow rate. The two

peaks were collected to yield the enantiomers as follows. Peak 1:

5R-(þ)-[4-(2-dimethylaminoethoxy)phenyl]-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3a-(R).

[R]_Dþ38 (c 0.3, MeOH). MS (m/z): MH^þ(430). Peak 2: 5S-

(-)-[4-(2-dimethylaminoethoxy)phenyl]-11,12-dihydro-5H-6,13-

5-[4-(2-Azepan-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-di-

oxabenzo[3,4]cyclohepta[1,2-a]naphthalen-8-ol, 4b. Following the

same three-step sequence described for preparation of 1b, lactal

14c was reacted in sequence with 1-[2-(4-iodophenoxy)ethyl]-

azepane, HCl, and then HF Py to yield the title compound 4b

3

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-2-ol, 3a-(S). [R]_D

-

as a yellow solid. Purity: 95% by LC-MS, R_f=2.9. MS (m/z)=

483.¹H NMR (acetone-d₆) δ δ1.54 (m, 8H), 2.68-2.95 (m, 8H),

3.98 (m, 2H), 4.74 (m, 2H), 6.18 (s, 1H), 6.21-7.39 (m, 11H). ¹H

NMR (DMSO-d₆) δ1.55 (broad s, 8H), 2.68-2.92 (m, 8H), 3.92 (t,

2H, J=6.6 Hz), 4.61 (m, 2H), 6.14-7.38 (m, 12H)., 9.56 (s, 1H).

HRMS m/z calcd for C₃₁H₃₃NO₄(M^þ) 483.2410, found 483.2421.

The racemic 5-[4-(2-azepan-1-ylethoxy)phenyl]-11,12-dihy-

dro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-8-ol,

4b (840 mg), was loaded onto a ChiralPak AD chiral HPLC

column (5 cm i.d. ꢀ 50 cm length) and eluted with 40% MeOH

and 60% IPA at the 100 mL/min flow rate. The two peaks were

collected to yield the two enantiomers. Peak 1: 5R-(þ)-[4-(2-aze-

pan-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]

36 (c 0.32, MeOH). MS (m/z): MH^þ(430).

Preparation of 5-[4-(2-Diethylaminoethoxy)phenyl]-11,12-di-

hydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-

diol, 3b. Following the procedure described for 1b, lactal 14b was

reacted in sequence with [2-(4-iodophenoxy)ethyl]diethylamine

3

HCl and then HF Py to yield the title compound as a yellow

3

solid. Purity: 96% by LC-MS, R_f=2.41. MS (m/z): MH^þ(458).

¹H NMR (CDCl₃) δ 1.1(m, 6H) 2.71 (m, 4H), 2.72 (m, 2H),

2.82 (m, 2H), 3.95 (m, 2H), 4.59 (m, 2H), 6.02 (s, 1H), 6.41-7.29

(m, 11H). HRMS m/z calcd for C₂₉H₃₂NO₄458.2331, found

458.2336. The racemic 5-[4-(2-diethylaminoethoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-

7562 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

Scheme 6

cyclohepta[1,2-a]naphthalen-8-ol, 4b-(R). [R]_Dþ37 (c 0.11,

MeOH). MS (m/z): MH^þ(483). Peak 2: 5S-(-)-[4-(2-azepan-1-

ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclo-

hepta[1,2-a]naphthalen-8-ol, 4b-(S). [R]_D-39 (c 0.51, MeOH).

MS (m/z): MH^þ(483).

2H), 6.35 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.2 (d, J=2 Hz, 1H), 6.0

(s, 1H), 4.6 (m, 2H), 3.95 (t, J=6 Hz, 2H), 3.7 (t, J=6 Hz, 2H),

2.8 (m, 2H). HPLC (Luna, 5 μm C18 (2), acetonitrile-water

with 0.05% TFA) t_R=5.749, over 97% pure. HRMS m/z calcd

for C₂₆H₂₄O₆432.1573, found 432.1567.

5-[4-(3-Hydroxypropoxy)phenyl]-11,12-dihydro-5H-6,13-dioxa-

benzo[3,4]cyclohepta[1,2-a]naphthal ene-2,8-diol, 1l. An amount of

1.28 g of tert-butyl-[3-(4-iodophenoxy)propoxy]dimethylsilane

(3.26 mmol) was dissolved in 10 mL of THF and cooled

to -78 °C before the slow addition of 1.2 mL of 2.5 M

n-butyllithium in hexane (3 mmol). After 1 h the lactol 14a

(400 mg) in 5 mL of THF was added slowly into the solution.

The reaction mixture was stirred for another 30 min, quenched

with aqueous ammonium chloride, extracted with ethyl acet-

ate, and dried over sodium sulfate. The crude material was

dissolved in 40 mL of toluene and cooled to 0 °C. Then 0.15 mL

of TFA (2 mmol) was added, and the mixture was kept at 0 °C

for 1 h. The reaction mixture was transferred into a separation

funnel and washed with 5% aqueous sodium bicarbonate and

brine in sequence. The organic layer was dried over sodium

sulfate and concentrated. The crude material was dissolved in

10 mL of THF, and 4 mL of 1.0 M tetrabutylammonium

fluoride in THF (4 mmol) was added slowly. The solution

was stirred at room temperature for 1 h and worked up by

washing with brine. The organic layer was dried over sodium

sulfate and concentrated. Flash column chromatography

Preparation of 5-[4-(2-Hydroxyethoxy)phenyl]-11,12-dihydro-

5H-6,13-dioxabenzo[3,4]cyclohepta [1,2-a]naphthalene-2,8-diol, 1k.

tert-Butyl-[3-(4-iodophenoxy)ethanoxy]dimethylsilane (10.87 g,

30 mmol) was dissolved in 100 mL of THF and cooled to -78 °C

before the slow addition of 12 mL of 2.5 M n-butyllithium in hexane

(30 mmol). After 1 h lactol in 20 mL of THF was added slowly into

the solution, stirred for another 30 min, quenched with aqueous

ammonium chloride, extracted with ethyl acetate, and dried over

sodium sulfate. After removal of the solvent, the crude material was

dissolved in 200 mL of toluene and cooled to 0 °C. Then 0.77 mL of

TFA (30 mmol) was added. The reaction mixture was kept at 0 °C

for 1 h and transferred into a separation funnel and washed with

5% aqueous sodium bicarbonate and brine in sequence. The

organic layer was dried over sodium sulfate and concentrated.

The crude material was dissolved in 100 mL of THF, and 30 mL of

1.0 M tetrabutylammonium fluoride in THF (30 mmol) was added

slowly. The solution was stirred at room temperature for 1 h and

worked up by washing with brine. The organic layer was dried over

sodium sulfate and concentrated. Flash column chromatography

1

yielded slight pink crystals, 2.3 mg, 55%. HNMR (DMSO-d₆,

400 MHz) δ(ppm) 9.6(s, 1H), 9.45(s, 1H), 7.3(d, J=9 Hz, 2H), 7.2

(d, J=9 Hz, 1H), 7.05 (d, J=9 Hz, 1H), 6.8 (d, J=9 Hz, 2H), 6.45

(m, 2H), 6.3 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.1 (m, 2H), 4.8 (t, J=

6 Hz, 1H), 4.45 (m, 2H), 3.9 (t, J=6 Hz, 2H), 3.7 (m, 2H), 2.8 (m,

1

yielded a slightly orange solid, 260 mg, 60% of 1l. HNMR

(CD₃OD, 300 MHz) δ (ppm) 7.3 (d, J=9 Hz, 2H), 7.15 (d, J=

9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.75 (d, J=9 Hz, 2H), 6.5 (m,

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7563

2H). MS: 783.3 (M þ 23), 761.3 (M þ 1). HPLC (Luna, 5 μm C18

(2), acetonitrile-water with 0.05% TFA) t_R= 5.749, over 97%

pure. HRMS m/z calcd for C₂₅H₂₂O₆418.1416 found 418.1434.

2-{4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]phenoxy}-

ethanol, 17a. 2-(4-Iodophenoxy)ethanol (20 g, 75.8 mmol) was

dissolved in 200 mL of THF at -10 °C before the slow addi-

tion of 152 mL of 1 M isopropylmagnesium bromide in THF

(152 mmol). The mixture was allowed to warm to room tem-

perature. After 30 min 8 g (15.2 mmol) of lactol 14a in 20 mL of

THF was added slowly into the solution. After being stirred for

another 30 min, the reaction was quenched with aqueous am-

moniumchloride, extracted with ethyl acetate, dried over sodium

sulfate, and concentrated. The crude material was dissolved in

300 mL of toluene and cooled to 0 °C. TFA (1.17 mL, 15.2 mmol)

was added, and the mixture was kept at 0 °C for 1 h. The reaction

mixture was transferred into a separation funnel and washed

with 5% aqueous sodiumbicarbonate and brine in sequence. The

organic layer was dried over sodium sulfate and concentrated.

Flash column chromatography yielded white crystals, 5.61 mg

(57%) of 17a. Chiral separation on preparation HPLC yielded,

with elution with 10% isopropanol in hexane, 2.4 and 2.2 g of

each enantiomer as pink crystals. ¹H NMR (CDCl₃, 300 MHz)

δ (ppm) 7.38 (d, J=9 Hz, 2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=

9 Hz, 1H), 6.9 (d, J=9 Hz, 2H), 6.6 (d, J=2 Hz, 1H), 6.5 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.3 (d,

J=2 Hz, 1H), 6.0 (s, 1H), 4.7 (t, J=6 Hz, 2H), 4.0 (t, J=6 Hz,

2H), 3.9 (m, 2H), 2.85 (t, J=6 Hz, 2H), 1.96 (t J=6 Hz, 1H), 0.97

(s, 9H), 0.94 (s, 9H), 0.2 (s, 6H), 0.16 (s, 6H). MS: 669 (M þ 23),

647 (M þ 1). HPLC: t_R=5.101, >99% pure. Anal. Calcd for

C₃₇H₅₀O₆Si₂: C, 68.69; H, 7.79, Si: 8.68. Found: C: 68.47, H:

7.67, Si: 9.32. Peak 1 as 17-(R), [R]_Dþ33.5° (c 0.30, CHCl₃). Peak

2 as 17a-(S), [R]_D-33.5° (c 0.36, CHCl₃).

Preparation of {4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]-

phenoxy}acetaldehyde, 20a (Scheme 6). The alcohol 17a (158 mg,

0.244 mmol) and Dess-Martin reagent (114 mg, 0.268 mmol) were

dissolved in 3 mL of dichloromethane. The solution was stirred at

room temperature for 1 h and then worked up by washing

continuously with 5% sodium bicarbonate and brine. The organic

layer was dried over anhydrous sodium sulfate and concentrated.

Flash column chromatography on silica gel with elution with 30%

ethyl acetate in hexane yielded a slightly yellow solid 100 mg

(63.5%) of 20a. ¹HNMR (CDCl₃, 300 MHz) δ (ppm) 9.8 (s,

1H), 7.4 (d, J=9 Hz, 2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=9 Hz,

1H), 6.75 (d, J=9 Hz, 2H), 6.6 (d, J=2 Hz, 1H), 6.55 (dd, ¹J=9 Hz,

²J=2 Hz, 1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 2H), 6.3 (d, J=2 Hz,

1H), 6.05 (s, 1H), 4.65 (t, J=6 Hz, 2H), 4.5 (s, 2H), 2.95 (t, J=6 Hz,

2H), 1.0 (s, 9H), 0.95 (s, 9H), 0.25 (s, 6H), 0.15 (s, 6H). MS: 645

(M þ 1), 677 (M þ 23). HRMS m/z calcd for C₃₇H₄₈O₆Si₂

644.2989 found 644.2911.

colorless oil (68% for two steps). ¹H NMR (CDCl₃, 300 MHz)

δ (ppm) 7.4 (d, J=9 Hz, 2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=

9 Hz, 1H), 6.75 (d, J=9 Hz, 2H), 6.6 (d, J=2 Hz, 1H), 6.55 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 2H), 6.3 (d,

J=2 Hz, 1H), 6.05 (s, 1H), 4.65 (t, J=6 Hz, 2H), 4.5 (s, 2H), 3.75

(s, 3H), 2.95 (t, J=6 Hz, 2H), 1.0 (s, 9H), 0.95 (s, 9H), 0.25 (s,

6H), 0.15 (s, 6H). MS: 697 (M þ 23), 675 (M þ 1). HPLC: R_f=

5.182, >99%. HRMS m/z calcd for C₃₈H₅₀O₇Si₂674.3095

found: 674.299 98.

Preparation of [4-(2,8-Dihydroxy-11,12-dihydro-5H-6,13-di-

oxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]acetic Acid

Methyl Ester, 1m. Di-TBS methyl ester 22a (371 mg, 0.55 mmol)

was dissolved in a mixture of 1 mL of pyridine and 5 mL of

acetonitrile at room temperature. Then 0.5 mL of 70% hydrogen

fluoride in pyridine was added and stirred overnight. The reaction

mixture was diluted with ethyl acetate and washed with 5%

aqueous sodium bicarbonate and brine. The organic layer was

dried over anhydrous sodium sulfate and concentrated. Flash

column chromatography on silica gel with elution with 50-100%

ethyl acetate in hexane yielded 1m as a solid (223 mg, 91%).

¹H NMR (DMSO-d₆, 300 MHz) δ (ppm) 9.5 (s, 1H), 9.36 (s,

1H), 7.2 (d, J=9 Hz, 2H), 7.07 (d, J=9 Hz, 1H), 6.95 (d, J=9 Hz,

1H), 6.67 (d, J=9 Hz, 2H), 6.35 (m, 2H), 6.2 (dd, ¹J=9 Hz, ²J=

2 Hz, 1H), 6.0 (d, J=2Hz,2H), 4.6(s,2H),4.4(m,2H),3.55(s,3H),

2.6 (m, 2H). MS: 469 (M þ 23). HPLC: t_R=3.039, >97% pure.

HRMS m/z calcd for C₂₆H₂₂O₇(M þ H^þ) 446.1366, found

446.1368.

3-{4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]phenoxy}-

propan-1-ol, 17b. 3-(4-Iodophenoxy)propanol (2.78 g, 10 mmol)

was dissolved in 20 mL of THF at room temperature before the

slow addition of 20 mL of 1 M isopropylmagnesium bromide in

THF (20 mmol). After 30 min lactol (1.05 g, 2 mmol) in 5 mL of

THF was added slowly into the solution. The mixture was stirred

for another 30 min, and the reaction was quenched with aqueous

ammonium chloride, extracted with ethyl acetate, dried over

sodium sulfate, and concentrated. The crude material was dis-

solved in 40 mL of toluene and cooled to 0 °C. Then 0.15 mL of

TFA (2 mmol) was added and the mixture was kept at 0 °C for

1 h. The reaction mixture was transferred into a separation

funnel and washed with 5% aqueous sodium bicarbonate and

brine in sequence. The organic layer was dried over sodium

sulfate and concentrated. Flash column chromatography yielded

white crystals, 610 mg (46% for two steps). Chiral separation on

preparation HPLC with elution with 10% isopropanol in hexane

gave each enantiomer 17b-(R) as peak 1 and 17b-(S) as peak 2.

¹H NMR (CDCl₃, 300 MHz) δ (ppm) 7.38 (d, J=9 Hz, 2H), 7.1

(d, J=9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.9(d, J=9 Hz, 2H), 6.6(d,

J=2 Hz, 1H), 6.5 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd, ¹J=9 Hz,

²J=2 Hz, 1H), 6.3 (d, J=2 Hz, 1H), 6.0 (s, 1H), 4.66 (t, J=6 Hz,

2H), 4.05 (t, J=6 Hz, 2H), 3.8 (m, 2H), 2.87 (t, J=6 Hz, 2H), 2.0

(m, 2H), 1.7(t, J=6 Hz, 1H), 0.97(s, 9H), 0.94(s, 9H), 0.2(s, 6H),

0.16 (s, 6H). MS: 683 (M þ 23), 661 (M þ 1). HPLC: t_R=5.101,

>97% pure. Anal. Calcd for C₃₈H₅₂O₆Si₂: C, 69.05; H, 7.93, Si:

8.50. Found: C: 68.68, H: 8.00; Si: 8.90. Peak 1, [R]_Dþ29.5°

(c 0.36, CHCl₃). Peak 2, [R]_D-29.5° (c 0.36, CHCl₃).

Preparation of 3-{4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]-

phenoxy}propionaldehyde, 20b. To the flask with 560 mg of the

starting alcohol 17b (0.847 mmol), 539 mg of Dess-Martin reagent

(1.27 mmol), and 142 mg of sodium bicarbonate (1.69 mmol) was

added 10 mL of dichloromethane. The solution was stirred at room

temperature for 1 h and then worked up by washing continuously

with 5% sodium bicarbonate and brine. The organic layer was dried

over anhydrous sodium sulfate and concentrated. Flash column

chromatography on silica gel with elution with 30% ethyl acetate

in hexane yielded a slightly yellow solid, 384 mg (69%) of 20b.

¹H NMR (CDCl₃, 300 MHz) δ (ppm) 9.8 (s, 1H), 7.4 (d, J=9 Hz,

2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.75 (d, J=9 Hz,

2H), 6.6 (d, J=2 Hz, 1H), 6.55 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.4

4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-dihydro-5H-6,13-

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]phenoxy}acetic

Acid, 21a. To a solution of sodium dihydrogen phosphate

(680 mg, 5.67 mmol) in 6.8 mL of water was added 16.7 mL of

tert-butyl alcohol and 5.2 mL of 2-methyl-2-butene. Aldehyde

20a (524 mg, 0.81 mmol) was dissolved in the solution, and

sodium chlorite (670 mg, 7.4 mmol) was added slowly. The

mixture was stirred at room temperature for 2 h, worked up by

washing with aqueous sodium hydrogen sulfite, 0.1 N HCl, and

brine in sequence. The organic layer was dried over anhydrous

sodium sulfate and concentrated. The crude product was used

for the next step without purification. MS: 661.2 (M þ 1).

Preparation of {4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-

yl]phenoxy}acetic Acid Methyl Ester, 22a. The crude acid, 21a,

was dissolved in a mixture of 7 mL of benzene and 2 mL of

methanol at room temperature followed by the addition of 1 mL

of 2 M TMSCHN₂in hexane. After concentration of the solvent

flash column chromatography yielded 371 mg of 22a as a

7564 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

(dd, ¹J=9 Hz, ²J=2 Hz, 2H), 6.3 (d, J=2 Hz, 1H), 6.05 (s, 1H), 4.65

(t, J=6 Hz, 2H), 4.2 (t, J=6 Hz, 2H), 2.8 (m, 4H), 0.97 (s, 9H), 0.92

(s, 9H), 0.20 (s, 6H), 0.10 (s, 6H).

J=9 Hz, 2H), 6.6 (d, J=2 Hz, 1H), 6.5 (dd, ¹J=9 Hz, ²J=2 Hz,

1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.3 (d, J=2 Hz, 1H), 6.0

(s, 1H), 4.64 (t, J=6 Hz, 2H), 4.1 (t, J=6 Hz, 2H), 3.5 (m, 2H),

2.85 (t, J=6 Hz, 2H), 2.43 (m, 4H), 0.96 (s, 9H), 0.93 (s, 9H),

0.19 (s, 6H), 0.15 (s, 6H). MS: 727 (M þ 23). [R]_D-35.5°

(c 0.32, CHCl₃). HRMS m/z calcd C₄₁H₅₄NO₇Si₂(M þ H^þ)

728.3439, found 728.3440.

Preparation of 3-{4-[2,8-Bis(tert-butyldimethylsilanyloxy)-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

len-5-yl]phenoxy}propionic acid, 21b. To a solution of 487 mg of

sodium dihydrogen phosphate (4.06 mmol) in 4.8 mL of water

were added 12 mL of tert-butyl alcohol and 4 mL of 2-methyl-

2-butene. Aldehyde 20b (384 mg, 0.58 mmol) was dissolved in the

solution, and 477 mg of sodium chlorite (5.2 mmol) was added

slowly. The mixture was stirred at room temperature for 2 h and

worked up by washing with aqueous sodium hydrogen sulfite,

0.1 N HCl, and brine in sequence. The organic layer was dried

over anhydrous sodium sulfate and concentrated. Flash column

chromatography on silica gel with elution with 20-80% ethyl

acetate in hexane yielded 359 mg of a slightly pink solid (92%) of

21b. ¹H NMR (DMSO-d₆, 300 MHz) δ (ppm) 12.3(s, 1H), 7.3(m,

3H), 7.1 (d, J=9 Hz, 1H), 6.8 (d, J=9 Hz, 2H), 6.6 (dd, ¹J=9 Hz,

²J=2 Hz, 1H), 6.55(d, J=2 Hz, 1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz,

1H), 6.2 (d, J=2 Hz, 2H), 4.57 (m, 2H), 4.07 (t, J=6 Hz, 2H),

2.9-2.7 (m, 2H), 2.6 (t, J=6 Hz, 2H), 0.93 (s, 9H), 0.90 (s, 9H),

0.18 (s, 6H), 0.14 (s, 6H). HPLC: 4.987 min, >95% pure. MS:

675 (M þ 1). Anal. Calcd for C₃₈H₅₀O₇Si₂: C, 67.62; H, 7.47; Si,

8.32. Found: C, 67.05, H, 7.49; Si, 8.29. HRMS m/z calcd for

C₃₈H₅₀O₇Si₂674.3095, found 674.3112.

1-{2-[4-(2,8-Dihydroxy-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]ethyl}pyrrolidine-2,5-

dione, 1i-(S). An amount of 220 mg of the 19i-(S) (0.30 mmol)

was dissolved in a mixture of 1 mL of pyridine and 10 mL of

acetonitrile at room temperature. Then 0.5 mL of 70% hydro-

gen fluoride in pyridine was added and stirred overnight. The

reaction mixture was diluted with ethyl acetate-THF (1:1) and

washed with 5% aqueous sodium bicarbonate and brine. The

organic layer was dried over anhydrous sodium sulfate and

concentrated. Flash column chromatography on silica gel with

elution with 20-100% ethyl acetate in hexane yielded 145 mg of

slightly pink solid (97%) of 1i. ¹HNMR (DMSO-d₆, 400 MHz)

δ (ppm) 9.6 (s, 1H), 9.48 (s, 1H), 7.3 (d, J=9 Hz, 2H), 7.2 (d, J=

9 Hz, 1H), 7.05 (d, J=9 Hz, 1H), 6.75 (d, J=9 Hz, 2H), 6.6

(m, 2H), 6.3 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.1 (m, 2H), 4.55 (m,

2H), 4.05 (m, 2H), 3.68 (t, J=6 Hz, 2H), 2.86 (m, 1H), 2.7 (m,

1H) 2.5 (m, 4H). HPLC: t_R=8.861, >95%. HPLC: t_R=3.158,

>95%. [R]_D-35.5° (c 0.22, CHCl₃). HRMS m/z calcd

C₂₉H₂₆NO₇(M þ H^þ) 500.1709, found 500.1712.

Preparation of 3-{4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[ 1,2-a]naphthalen-5-yl]-

phenoxy}propionic Acid Methyl Ester, 22b. An amount of 187 mg of

the acid (0.277 mmol) was dissolved in a mixture of 3.5 mL of

benzene and 1 mL of methanol at room temperature followed by

the addition of 0.21 mL of 2 M TMSCHN₂in hexane. The mixture

was concentrated and purified by flash column chromatography.

¹H NMR (CDCl₃, 300 MHz) δ (ppm) 7.4 (d, J=9 Hz, 2H), 7.1

(d, J=9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.75 (d, J=9 Hz, 2H),

6.6 (d, J=2 Hz, 1H), 6.55 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd, ¹J=

9 Hz, ²J=2 Hz, 2H), 6.3 (d, J=2 Hz, 1H), 6.05 (s, 1H), 4.65 (t, J=

6 Hz, 2H), 4.17 (t, J=6 Hz, 2H), 3.69 (s, 3H), 2.86 (t, J=6 Hz, 2H),

2.75 (t, J=6 Hz, 2H), 0.97 (s, 9H), 0.93 (s, 9H), 0.20 (s, 6H), 0.16 (s,

6H). MS: 711 (M þ 23), 689 (M þ 1). HPLC: t_R=5.280, >97%

pure. HRMS m/z calcd for C₃₉H₅₃O₇Si₂689.3330, found 689.3328.

3-[4-(2,8-Dihydroxy-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]propionic Acid, 1o. An

amount of 90 mg of the starting di-TBS acid (0.13 mmol) was

dissolved in a mixture of 0.4 mL of pyridine and 2 mL of

acetonitrile at room temperature. Then 0.2 mL of 70% hydrogen

fluoride in pyridine was added and stirred overnight. The mixture

was diluted with ethyl acetate-THF (1:1) and washed with 5%

aqueous sodium bicarbonate and brine. The organic layer was

dried over anhydrous sodium sulfate and concentrated. Flash

column chromatography on silica gel with elution with 10%

methanol in dichloromethane yielded 57 mg of a slightly pink solid

(98%). ¹HNMR (acetone-d₆, 300 MHz) δ (ppm) 9 (bs, 1H), 7.4 (d,

J=9 Hz, 2H), 7.25 (d, J=9 Hz, 1H), 7.1 (d, J=9 Hz, 1H), 6.86 (d,

J=9 Hz, 2H), 6.58 (m, 2H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.27

(d, J=2 Hz, 1H), 6.1 (s, 1H), 4.65 (m, 2H), 4.2 (t, J=6 Hz, 2H), 2.9

(m, 2H), 2.75 (t, J=6 Hz, 2H). MS: 469 (M þ 23), 447 (M þ 1).

HPLC: t_R=2.891, >97% pure. HRMS m/z calcd for C₂₆H₂₃O₇

447.1444, found 447.14443.

Preparation of 1-{2-[4-(2,8-Dihydroxy-11,12-dihydro-5H-6,13-

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]ethyl}-

pyrrolidine-2,5-dione, 1i-(R). Same procedure as for 1i-(S) and

starting from alcohol 17a-(R). [R]_Dþ35.5° (0.31, CHCl₃).

1-{3-[4-(2,8-Dihydroxy-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]propyl}pyrrolidine-2,5-

dione, 1j-(R). The title compound was prepared according to

the procedure described for 1i starting from alchohol 17b-(R).

¹HNMR (DMSO-d₆, 400 MHz) δ (ppm) 9.6 (s, 1H), 9.48 (s, 1H),

7.3 (d, J=9 Hz, 2H), 7.2 (d, J=9 Hz, 1H), 7.05 (d, J=9 Hz, 1H),

6.75 (d, J=9 Hz, 2H), 6.6 (m, 2H), 6.3 (dd, ¹J=9 Hz, ²J=2 Hz,

1H), 6.1(m, 2H), 4.55 (m, 2H), 4.05 (m, 2H), 3.68 (t, J=6 Hz, 2H),

2.86 (m, 1H), 2.7 (m, 1H), 2.5 (s, 4H). HPLC: t_R=2.905 >97%.

HRMS m/z calcd C₃₀H₃₀NO₈(M þ H^þ) 532.1971, found

532.1973, [R]_Dþ25.3° (c 0.61, CHCl₃).

1-{3-[4-(2,8-Dihydroxy-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]propyl}pyrrolidine-2,5-

dione, 1j-(S). The title compound was prepared according to

the procedure described for 1i starting from alchohol 17b-(S).

¹HNMR (DMSO-d₆, 400 MHz) δ (ppm) 9.6 (s, 1H), 9.48 (s, 1H),

7.3 (d, J=9 Hz, 2H), 7.2 (d, J=9 Hz, 1H), 7.05 (d, J=9 Hz, 1H),

6.75 (d, J=9 Hz, 2H), 6.6 (m, 2H), 6.3 (dd, ¹J=9 Hz, ²J=2 Hz,

1H), 6.1 (m, 2H), 4.55 (m, 2H), 3.87 (t, J=6 Hz, 2H), 3.47 (t, J=

6 Hz, 2H), 2.86 (m, 1H), 2.7 (m, 1H) 2.56 (s, 4H), 1.85 (m, 2H).

HPLC: t_R=3.232 >99%. HRMS m/z calcd C₃₀H₃₀NO₈(Mþ

H^þ) 532.1971, found 532.1969. [R]_D-29.3° (c 1, CHCl₃).

Preparation of (S)-2,8-Bis(tert-butyldimethylsilanyloxy)-5-[4-

(3-iodopropoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalene, 18b-(S). To a solution of the

starting alchol 17b-(S) (370 mg, 0.572 mmol) in 5 mL of DMF

was added 517 mg (1.14 mmol) of methyltriphenoxypho-

sphonium iodide at ambient temperature. The mixture was

stirred for 30 min, diluted with ethyl acetate, and washed with

water and then brine. The organic layer was dried over

sodium sulfate and concentrated. Then 400 mg of white solid

was yielded after purification on silica gel, eluting with 10%

1-(2-{4-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-dihydro-

5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]phe-

noxy}ethyl)pyrrolidine-2,5-dione, 19i. In a flask, 49.5 mg of

succinimide (0.5 mmol) and 131.2 mg of triphenylphosphine

(0.5 mmol) were dissolved in 5 mL of THF. The starting

alcohol 17b-(S) (323 mg, 0.5 mmol) in 1 mL of THF and

0.079 mL of DEAD in 1 mL of THF were added into the flask

at the same rate by syringes. The mixture was stirred overnight

at room temperature. After concentration of the solvent, flash

column chromatography gave a white powder of 19i-(S)

1

ethyl acetate in hexane (94%). H NMR (CDCl₃, 300 MHz)

δ (ppm) 7.38 (d, J=9 Hz, 2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=

9 Hz, 1H), 6.9 (d, J=9 Hz, 2H), 6.6 (d, J=2 Hz, 1H), 6.5 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.3

(d, J=2 Hz, 1H), 6.0 (s, 1H), 4.66 (t, J=6 Hz, 2H), 3.96 (t, J=

6 Hz, 2H), 3.33 (t, J=6.6 Hz, 2H), 2.85 (m, 2H), 2.2 (m, 2H),

0.98 (s, 9H), 0.95 (s, 9H), 0.21 (s, 6H), 0.17 (s, 6H). MS: 793

(M þ 23), 771 (M þ 1). HPLC: t_R=5.620, >98% pure. Anal.

1

(0.28 g, 77%). H NMR (CDCl₃, 400 MHz) δ (ppm) 7.3 (d,

J=9 Hz, 2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.9 (d,

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7565

Calcd for C₃₈H₅₁IO₅Si₂: C, 59.21; H, 6.67; I, 16.46. Found: C,

59.17; H, 6.67; I, 17.13. [R]_Dþ28.7° (c 0.36, CHCl₃).

to the procedure described for 1p-(S), starting from iodide

18a-(R). ¹H NMR (DMSO-d₆, 300 MHz) δ (ppm) 9.95 (bs,

1H), 9.83(bs, 1H), 7.65-7.18 (m, 3H), 6.95 (m, 2H), 6.80 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.80 (m, 2H), 6.32 (dd, ¹J=9 Hz, ²J=

2 Hz, 1H), 6.15 (m, 2H), 4.55 (m, 2H), 3.95 (t, J=6 Hz, 2H),

2.85 (m, 1H), 2.70 (m, 1H), 2.60 (t, J=6 Hz, 2H), 2.40 (m, 4H),

2.40 (m, 4H)2.15 (s, 3H). LC-MS: 2.514 min, >97%, m/z 501

(M þ 1). [R]_Dþ66° (c 0.21, MeOH). LC-MS: R_f=2.819 min,

>97% pure, m/z 501 (M þ 1). HRMS m/z calcd for C₃₀H₃₃-

N₂O₅(M þ H^þ) 501.2389, found 501.2411.

Preparation of (S)-2,8-Bis(tert-butyldimethylsilanyloxy)-5-[4-

(3-iodopropoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalene, 18b-(R). The title compound was

prepared according to the procedure described for 18-(S), start-

ing from alchohol 17b-(R): [R]_D-29° (c 0.39, CHCl₃).

Preparation of 5-[4-(3-Piperidin-1-ylpropoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-

diol, 1p-(S). Step 1. To a flask was added the starting iodide

18b-(S) (220 mg, 0.285 mmol), potassium bicarbonate (42.8 mg,

0.428 mmol), 42.3 μL of piperidine (0.428 mmol), and 3 mL of

acetonitrile. The mixture was kept at 60 °C overnight, diluted with

100 mL of ethyl acetate, and washed with brine twice. The organic

layer was dried over sodium sulfate and concentrated. Flash

column chromatography yielded 172 mg of white powder (83%).

19p-(S): ¹H NMR (CDCl₃, 300 MHz) δ (ppm) 7.38 (d, J=9 Hz,

2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.9 (d, J=9 Hz,

2H), 6.6 (d, J=2 Hz, 1H), 6.5 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.3 (d, J=2 Hz, 1H), 6.0 (s, 1H), 4.66 (t,

J=6 Hz, 2H), 3.96 (t, J=6 Hz, 2H), 2.85 (m, 2H), 2.4 (m, 6H), 1.9

(m, 2H), 1.55 (m, 4H), 1.42 (m, 2H), 0.97 (s, 9H), 0.94 (s, 9H), 0.20

(s, 6H), 0.16 (s, 6H). MS: 728 (M þ 1). HPLC: t_R=4.609, >99%

pure. Anal. Calcd for C₄₃H₆₁NO₅Si₂: C, 70.93; H, 8.44; N, 1.92.

Found: C, 70.62; H, 8.68; N, 1.82. [R]_D-24° (c 0.30, CHCl₃).

Step 2. The starting material (150 mg, 0.21 mmol) was

dissolved in a mixture of 1 mL of pyridine and 3 mL of

acetonitrile at room temperature. Then 0.5 mL of 70% hydro-

gen fluoride in pyridine was added, and the mixture was stirred

overnight, diluted with ethyl acetate-THF (1:1), and washed

with 5% aqueous sodium bicarbonate and brine. The organic

layer was dried over anhydrous sodium sulfate and concen-

trated. Flash column chromatography on silica gel with elution

with 0-5% methanol in dichloromethane yielded a slightly pink

solid of 1p-(S). ¹H NMR (CD₃OD, 300 MHz) δ (ppm) 7.38 (d,

J=9 Hz, 2H), 7.1 (d, J=9 Hz, 1H), 7.0 (d, J=9 Hz, 1H), 6.9 (d,

J=9 Hz, 2H), 6.6 (d, J=2 Hz, 1H), 6.5 (dd, ¹J=9 Hz, ²J=2 Hz,

1H), 6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.3 (d, J=2 Hz, 1H), 6.0 (s,

1H), 4.6 (m, 2H), 3.96 (t, J=6 Hz, 2H), 2.8 (m, 8H), 2.0 (m, 2H),

1.67 (m, 4H), 1.53 (m, 2H). MS: 500 (M þ 1). HPLC: t_R=

5.226, >97% pure. HRMS m/z calcd C₃₀H₃₀NO₈(MþH^þ),

C₃₁H₃₄NO₅(M þ H^þ) 500.2437, found 500.2539. Anal. Calcd:

C, 74.53; H, 6.66; N, 2.80; O, 16.01. Found: C, 74.48; H, 6.85; N,

2.78. [R]_D14° (c 0.20, MeOH).

Preparation of R-5-{4-[2-(4-Methylpiperazin-1-yl)ethoxy]phenyl}-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 1h-(S). [R]_D-59° (c 0.61, MeOH).

2-{3-[2,8-Bis(tert-butyldimethylsilanyloxy)-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl]phenoxy}-

ethanol, 23. 3-(3-Iodophenoxy)propanol (6 g, 22.7 mmol) was

dissolved in 100 mL of THF at room temperature before the slow

addition of 45 mL of 1 M isopropylmagnesium bromide in THF

(20 mmol). After 30 min lactol 14a (2.37 g, 4.5 mmol) in 30 mL of

THF was added slowly into the solution. After being stirred for

another 30 min the reaction was quenched with aqueous ammo-

nium chloride, extracted with ethyl acetate, dried over sodium

sulfate, and concentrated. The crude material was dissolved in

200 mL of toluene and cooled to 0 °C. TFA (0.4 mL, 4.5 mmol)

was added, and the mixture was kept at 0 °C for 1 h. The reaction

mixture was transferred into a separation funnel and washed

with 5% aqueous sodium bicarbonate and brine in sequence.

The organic layer was dried over sodium sulfate and concen-

trated. Flash column chromatography yielded white crystals

1.13 g, (77% for two steps) of 23. ¹H NMR (CDCl₃, 300 MHz)

δ (ppm) 7.17-7.0 (m, 5H), 6.75 (dd, ¹J=9 Hz, ²J=2 Hz, 1H),

6.6 (d, J=2 Hz, 1H), 6.55 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.4 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.35 (d, J=2 Hz, 1H), 6.05 (s, 1H), 4.66

(t, J=6 Hz, 2H), 4.0 (t, J=6 Hz, 2H), 3.85 (m, 2H), 2.87 (m, 2H),

2.0 (t, J=6 Hz, 1H), 0.97 (s, 9H), 0.94 (s, 9H), 0.2 (s, 6H), 0.16 (s,

6H). MS: 647 (M þ 1), 669 (M þ 23). HPLC: t_R=10.740. Purity

>97% pure. HRMS cacld for C₃₇H₅₁O₆Si₂647.3224, found

647.3290. Chiral separation on preparation HPLC with elution

with 10% isopropanol in hexane gave each enantiomer as

crystals. Peak 1 as 23-(R), [R]_Dþ51° (c 0.30, CHCl₃). Peak 2 as

23-(S), [R]_D-51° (c 0.31, CHCl₃).

(R)-2,8-Bis(tert-butyldimethylsilanyloxy)-5-[3-(2-iodoethoxy)-

phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]-

naphthalene, 24-(R). To a solution of the starting material 23-(R)

(370 mg, 0.572 mmol) in 5 mL of DMF was added methyltri-

phenoxyphosphonium iodide (517 mg, 1.14 mmol) at ambient

temperature, and the mixture was stirred for 30 min, diluted with

ethyl acetate, and washed with water and then brine. The organic

layer was dried over sodium sulfate and concentrated. Awhite

solid was yielded after purification on silica gel, eluting with

10% ethyl acetate in hexane (380 mg, 89%). ¹H NMR (CDCl₃,

400 MHz) δ (ppm) 7.15-7.0 (m, 5H), 6.75 (dd, ¹J=9 Hz, ²J=

2 Hz, 1H), 6.6 (d, J=2 Hz, 1H), 6.53(dd, ¹J=9 Hz, ²J=2 Hz, 1H),

6.4 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.3 (d, J=2 Hz, 1H), 6.05 (s,

1H), 4.6 (m, 2H), 4.15 (t, J=6 Hz, 2H), 3.3 (m, 2H), 2.85 (m, 2H),

0.97 (s, 9H), 0.94 (s, 9H), 0.2 (s, 6H), 0.16 (s, 6H). [R]_Dþ53°

(c 0.33, CHCl₃). HRMS cacld for C₃₇H₅₀IO₅Si₂(M þ H^þ)

757.2242, found 757.2199.

Preparation of 5-[4-(3-Piperidin-1-ylpropoxy)phenyl]-11,12-

dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-

2,8-diol, 1p-(S). The title compound was prepared according to

the procedure described for 1p-(S) starting from iodide 18b-(R):

[R]_Dþ17° (c 0.24, MeOH).

Preparation of (R)-5-[4-(2-Thiomorpholin-4-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 1g-(R). The title compound was prepared according

to the procedure described for 1p-(S) starting from iodide

18a-(R). ¹H NMR (DMSO-d₆, 400 MHz) δ (ppm) 9.65 (bs,

1H), 9.53 (bs, 1H), 7.25-7.1 (m, 3H), 6.85 (m, 2H), 6.70 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.60(dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.45-

6.32 (m, 2H), 6.15 (m, 2H), 4.65 (m, 2H), 3.95 (t, J=6 Hz, 2H),

2.75 (m, 1H), 2.76 (m, 5H), 2.65 (t, J=6 Hz, 2H), 2.57 (m, 4H).

LC-MS: 2.819 min, >97%, m/z 504 (M þ 1). HRMS m/z calcd

C₂₉H₃₀NO₅S 504.1845, found 504.1865. Anal. Calcd: C, 69.16;

H, 5.80; N, 2.78; O, 15.88; S, 6.37. Found: C, 69.28; H, 5.79; N,

2.79. [R]_Dþ66° (c 0.24, MeOH).

(S)-2,8-Bis(tert-butyldimethylsilanyloxy)-5-[3-(2-iodoethoxy)-

phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]-

naphthalene, 24-(S). [R]_D-53.5° (c 0.31, CHCl₃).

5R-[3-(2-Piperidin-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-diol, 2a-(R). The

title compound was prepared according to the procedure de-

scribed for 1p-(S) starting from iodide 24-(R) and piperidine.

¹HNMR (DMSO-d₆, 400 MHz) δ (ppm) 9.63 (s, 1H), 9.5 (s, 1H),

7.25-7.1 (m, 3H), 6.95 (m, 2H), 6.8 (dd, ¹J=9 Hz, ²J=2 Hz, 1H),

6.5(dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.45 (d, J=2 Hz, 1H), 6.3 (dd,

¹J=9 Hz, ²J=2 Hz, 1H), 6.2 (m, 2H), 4.55 (m, 2H), 4.0 (m, 2H),

2.8 (m, 2H), 2.7 (m, 2H), 2.4 (m, 4H), 1.5 (m, 4H), 1.4 (m, 2H).

Preparation of (S)-5-[4-(2-Thiomorpholin-4-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 1g-(S). The title compound was prepared according

to the procedure described for 1p-(S), starting from iodide

18a-(S): [R]_D-50.5° (c 1.1, CHCl₃).

Preparation of R-5-{4-[2-(4-Methylpiperazin-1-yl)ethoxy]phenyl}-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 1h-(R). The title compound was prepared according

7566 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23

Jain et al.

LC-MS: 2.705 min, >97%, m/z 486 (M þ 1). [R]_Dþ44.8°

(c 0.4, MeOH). HRMS, m/z calcd for C₃0H₃₂NO₅(M þ H^þ)

486.5788, found 486.5793. Anal. Calcd for C₃₁H₃₅NO₆(M þ

MeOH): C, 71.93; H, 6.82; N, 2.71; O, 18.55. Found: C, 71.96; H,

6.86; N, 2.77.

5S-[3-(2-Piperidin-1-ylethoxy)phenyl]-11,12-dihydro-5H-6,13-

dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-diol, 2a-(S). The

title compound was prepared according to the procedure de-

scribed for 1p-(S), starting from iodide 24-(S) and piperidine:

[R]_D-46° (c 0.31, MeOH).

δ 1.40 (m, 2H), 1.59 (m, 4H), 2.49 (broad s, 4H), 2.72 (m,

2H), 2.91 (m, 2H), 3.71 (s, 3H), 3.78 (s, xH), 4.05 (m, 2H),

4.69 (m, 2H), 6.05 (s, 1H), 6.36-7.39 (m, 10H). MS (m/z):

MH^þ(514). ¹³C NMR (400 MHz, DMSO-d₆): 160.08, 159.35,

158.6, 157.3, 152.32, 130.68, 129.33, 128.85, 128.17, 125.36, 124.14,

123.19, 128.85, 128.17, 125.36, 124.14, 123.19, 117.00, 114.18,

109.67, 107.37, 106.04, 102.27, 77.84, 76.58, 65.38, 57.29, 55.18,

55.29, 54.19, 27.95, 25.5, 23.88. Anal. Calcd: C, 74.68; H, 7.05; N,

2.72; O, 15.54. Found: C, 74.71; H, 7.09; N, 2.69. Purity >98%

by LC-MS, R_f=4.4. MS (m/z): MH^þ(514). [R]²⁵þ7.2 (c 0.38 g/

100 mL, CHCl₃).

Preparation of 2-Methoxy-5S-(-)-[4-(2-piperidin-1-ylethoxy)-

phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]-

naphthalen-8-ol, 6-(S), and 8-Methoxy-5S-(-)-[4-(2-piperidin-1-

ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta-

[1,2-a]naphthalen-2-ol, 5-(S). 5S-(-)-[4-(2-Piperidin-1-ylethoxy)-

phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]-

naphthalene-2,8-diol (10 g) 1a-(S) was dissolved in CH₃CN/

MeOH (3:1) (280 mL) and 1.1 equiv of TMSCH₂N₂(2 M in

hexane 10.2 mL), and the mixture was stirred overnight. The

reaction mixture was concentrated to dryness and purified on

SiO₂using 5-10% MeOH in CH₂Cl₂to yield a mixture of the title

compounds as yellow foam. The mixture of compounds (2.9 g)

was loaded onto a ChiralPak AD chiral HPLC column (5 cm i.d. ꢀ

50 cm length) and eluted with 100% IPA at the 150 mL/min flow

rate. The two peaks were collected to yield the two title compounds

as follows.

5R-[3-(2-Thiomorpholin-4-ylethoxy)phenyl]-11,12-dihydro-5H-

6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-2,8-diol, 2c-(R).

The title compound was prepared according to the procedure

described for 1p-(S), starting from iodide 24-(R) and thiomorpho-

1

line. H NMR (DMSO-d₆, 400 MHz) δ (ppm) 9.65 (bs, 1H),

9.53(bs, 1H), 7.25-7.1 (m, 3H), 6.95 (m, 2H), 6.80 (dd, ¹J=9 Hz,

²J=2 Hz, 1H), 6.50 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.45 (d, J=2 Hz,

1H), 6.32 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.15 (m, 2H), 4.65 (m, 2H),

3.95 (t, J=6 Hz, 2H), 2.85 (m, 1H), 2.70 (m, 5H), 2.65 (t, J=6 Hz,

2H), 2.57 (m, 4H). LC-MS: 2.719 min. Purity >97%, m/z 504

(M þ 1). HRMS m/z calcd C₂₉H₃₀NO₅S 504.1845, found

504.1865. Anal. Calcd: C, 69.16; H, 5.80; N, 2.78; O, 15.88; S,

6.37. Found: C, 69.31; H, 5.77; N, 2.77. [R]_Dþ56° (c 0.24, MeOH).

Preparation of 5S-[3-(2-Thiomorpholin-4-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 2c-(S). The title compound was prepared according

to the procedure described for 1p-(S), starting from iodide 24-(S)

and thiomorpholine: [R]_D-56° (c 0.43, MeOH).

Peak 1: 2-methoxy-5S-(-)-[4-(2-piperidin-1-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

len-8-ol, 6-(S). ¹H NMR (DMSO-d₆) δ 1.42 (s, 2H), 1.61 (s, 4H),

2.41-3.14 (m, 8H), 3.67 (s, 3H), 4.24 (s, 2H), 4.59 (m, 2H), 6.14-

7.28 (m, 11H). Purity >97 by LC-MS, R_f=2.9. MS (m/z): MH^þ

(500). HRMS calcd for C₃₁H₃₄NO₅(M þ Hþ) 500.2437, found

500.1987. Anal. Calcd: C, 74.38; H, 6.85; N, 2.80; O, 15.98. Found:

C, 74.41; H, 6.91; N, 2.77.

Preparation of 5R-{3-[2-(4-Methylpiperazin-1-yl)ethoxy]phenyl}-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 2b-(R). The title compound was prepared according

to the procedure described for 1p-(S), starting from iodide

24-(R) and 1-methylpiperazine. ¹H NMR (DMSO-d₆, 300 MHz)

δ (ppm) 9.65 (bs, 1H), 9.53(bs, 1H), 7.25-7.1 (m, 3H), 6.95

1

2

(m, 2H), 6.80 (dd, J = 9 Hz, J = 2 Hz, 1H), 6.50 (m, 2H),

6.32 (dd, ¹J=9 Hz, ²J=2 Hz, 1H), 6.15 (m, 2H), 4.55 (m, 2H),

3.95 (t, J=6 Hz, 2H), 2.85 (m, 1H), 2.70 (m, 1H), 2.60 (t, J=6 Hz,

2H), 2.40 (m, 4H), 2.30 (m, 4H)2.15 (s, 3H). LC-MS: 2.514 min,

>97%, m/z 501 (M þ 1). HRMS m/z calcd for C₃₀H₃₃N₂O₅-

(M þ H^þ) 501.2389, found 501.2459. [R]_Dþ56° (c 0.21, MeOH).

Preparation of 5S-{3-[2-(4-Methylpiperazin-1-yl)ethoxy]phenyl}-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 2b-(S). The title compound was prepared according

to the procedure described for 1p-(S), starting from iodide 24-(S)

and 1-methylpiperazine: [R]_D-53° (c 0.31, MeOH).

Peak 2: 8-methoxy-5S-(-)-[4-(2-piperidin-1-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

1

len-2-ol, 5-(S). H NMR (CD₃OD) δ 1.41 (broad s, 2H), 1.59

(broad s, 4H), 2.50 (broad s, 4H0, 2.68 (m, 2H), 2.81 (m, 2H), 3.78

(m, 2H), 4.61 (t, 2H, J=6.0 Hz), 6.02 (s, 1H), 6.22-7.29 (m, 10H).

MS (m/z): MH^þ(500). HRMS calcd for C₃₁H₃₄NO₅(M þ H^þ)

500.2437, found 500.1687. Purity >96 by LC-MS, R_f=2.88. MS

(m/z): MH^þ(500).

Preparation of 2-Methoxy-5R-(-)-[4-(2-piperidin-1-ylethoxy)-

phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]-

naphthalen-8-ol, 7-(R), and 8-Methoxy-5R-(-)-[4-(2-piperidin-1-

ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta-

[1,2-a]naphthalen-2-ol, 6-(R). 5R-(-)-[4-(2-Piperidin-1-ylethoxy)-

phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]-

naphthalene-2,8-diol 1a-(R) (5 g) was dissolved in CH₃CN/MeOH

(3:1) (150 mL) and 1.1 equiv of TMSCH₂N₂(2 M in hexane, 5 mL),

and the mixture was stirred overnight. The reaction mixture was

concentrated to dryness and purified on SiO₂using 5-10% MeOH

in CH₂Cl₂to yield a mixture of the title compounds as yellow foam.

The mixture of compounds (1.4 g) was loaded onto a ChiralPak

AD chiral HPLC column (5 cm i.d. ꢀ 50 cm length) and eluted with

100% IPA at the 150 mL/min flow rate. The two peaks were

collected to yield the two title compounds as follows.

Peak 1: 2-methoxy-5R-(-)-[4-(2-piperidin-1-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

len-8-ol, 6-(R). ¹H NMR (DMSO-d₆) δ 1.42 (s, 2H), 1.61 (s, 4H),

2.41-3.14 (m, 8H), 3.67 (s, 3H), 4.24 (s, 2H), 4.59 (m, 2H), 6.14-

7.28 (m, 11H). ¹³C NMR (DMSO, 400 MHz): 159.92, 158.18,

157.78, 157.42, 152.29, 130.75, 129.35, 128.14, 125.66, 123.97,

121.67, 117.18, 111,15, 110.95, 108.75, 106.87, 102.27, 77.58,

76.53, 65.37, 57.29, 55.09, 54.29, 29.00, 25.50, 23.88 (m, 10H).

Purity >96% by LC-MS, R_f=2.9. MS (m/z):MH^þ(500). HRMS

calcd for C₃₁H₃₄NO₅(M þ H^þ) 500.2437, found 500.1987. Anal.

Calcd: C, 74.38; H, 6.85; N, 2.80; O, 15.98. Found: C, 74.46; H,

6.97; N, 2.79. [R]²⁵þ78.2 (c 0.88 g/100 mL, MeOH).

Preparation of 5S-(-)-1-{2-[4-(2,8-Dimethoxy-11,12-dihydro-

5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl)phenoxy]-

ethyl}piperidine, 7-(S). 5S-(-)-[4-(2-Piperidin-1-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

lene-2,8-diol, 1a-(S) (1 g), was dissolved in CH₃CN/MeOH (3:1)

(28 mL) and TMSCH₂N₂(2 M in hexane, 10 mL, excess), and

the mixture was stirred overnight. The reaction mixture was con-

centrated to dryness and purified on SiO₂using 5% MeOH in

1

CH₂Cl₂to yield the title compound as a yellow solid. H NMR

(CDCl₃) δ 1.40 (m, 2H), 1.59 (m, 4H), 2.49 (broad s, 4H), 2.72

(m, 2H), 2.91 (m, 2H), 3.71 (s, 3H), 3.78 (s, xH), 4.05 (m, 2H), 4.69

(m, 2H), 6.05 (s, 1H), 6.36-7.39 (m, 10H). Purity 97% by LC-MS,

R_f=4.1. MS (m/z): MH^þ(514). HRMS: m/z calcd for C₃₂H₃₆NO₅

(M þ H^þ) 514.2593, found 514.2603. [R]²⁵-7.9 (c 0.6 g/100 mL,

CHCl₃).

Preparation of 5R-(-)-1-{2-[4-(2,8-Dimethoxy-11,12-dihy-

dro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphthalen-5-yl)-

phenoxy]ethyl}piperidine, 7-(R). 5S-(-)-[4-(2-Piperidin-1-

ylethoxy)phenyl]-11,12-dihydro-5H-6,13-dioxabenzo[3,4]-

cyclohepta[1,2-a]naphthalene-2,8-diol, 1a-(R) (1.1 g), was

dissolved in CH₃CN/MeOH (3:1) (30 mL) and TMSCH₂N₂

(2 M in hexane, 11.3 mL, excess), and the mixture was stirred

overnight. The reaction mixture was concentrated to dry-

ness and purified on SiO₂using 5% MeOH in CH₂Cl₂to

yield the title compound as a yellow solid. ¹H NMR (CDCl₃)

Article

Journal of Medicinal Chemistry, 2009, Vol. 52, No. 23 7567

Peak 2: 8-methoxy-5R-(-)-[4-(2-piperidin-1-ylethoxy)phenyl]-

11,12-dihydro-5H-6,13-dioxabenzo[3,4]cyclohepta[1,2-a]naphtha-

len-2-ol, 6-(R). H NMR (CD₃OD) δ 1.41 (broad s, 2H), 1.59

modulator. J. Enzyme Inhib. Med. Chem. 2005, 20 (2), 165–177.

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1

(broad s, 4H), 2.50 (broad s, 4H0, 2.68 (m, 2H), 2.81 (m, 2H),

3.78 (m, 2H), 4.61 (t, 2H, J=6.0 Hz), 6.02 (s, 1H), 6.22-7.29 (m,

11H). ¹³C NMR (DMSO, 400 MHz) 159.21, 158.45, 158.41,

157.39, 152.29, 130.37, 129.29, 129.10, 128.9, 124.39, 124.131,

123.36, 116.69, 111.73, 109.11, 108.55, 107.30, 103.64, 77.74,

76.40, 65.37, 57.30, 55.17, 54.30, 28.00, 25.51, 23.88). HRMS calcd

for C₃₁H₃₄NO₅(M þ H^þ) 500.2437, found 500.2217. Anal. Calcd:

C, 74.38; H, 6.85; N, 2.80; O, 15.98. Found: C, 74.56; H, 6.88; N,

2.91. [R]²⁵þ36 (c 0.38 g/100 mL, MeOH).

Acknowledgment. We are grateful to Drs. Rehka Shah,

Yong Zhou, and Brigitte Segmuller for stereochemistry dis-

cussions and to Drs. Mark J. Macielag and William Murray

for their guidance and support.

Supporting Information Available: Additional experimental

procedures, NMR and X-ray data, and additional supporting

data. This material is available free of charge via the Internet at

http://pubs.acs.org.

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Article Doi

Identification and structure - Activity relationships of chromene-derived selective estrogen receptor modulators for treatment of postmenopausal symptoms

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