1-Aryl-2-pyridyl-3,4-dihydronaphthalenes: Photofluorogenic ligands for the estrogen receptor

Article abstract of DOI:10.1021/jo9618029

Three 1,2-substituted-3,4-dihydronaphthalenes that are pyridine analogs of the antiestrogen desmethylnafoxidine were prepared and evaluated as fluorescent ligands for the estrogen receptor. These compounds represent a class of fluorescent probes that we term 'photofluorogenic', denoting their ability to exist initially as a high affinity though weakly fluorescent stilbazole form which can be photocyclized-oxidized to a highly fluorescent though low affinity azaphenanthrenoid form. These probes also contain an aziridine function that provides a means for their permanent, covalent attachment to the receptor. The three dihydronaphthalene systems were prepared by efficient routes from α-(2-, 3-, and 4-pyridyl)acetophenone precursors. They demonstrate high apparent affinity for the estrogen receptor and show time-dependent irreversible inactivation, consistent with their covalent attachment to the receptor via the aziridine function. Each system is converted into an azaphenanthrene by photocyclization-oxidation of the cis-stilbazole unit. The absorbance and fluorescence emission spectra of the dihydronaphthalene precursors and azaphenanthrene products have been characterized, and they display marked sensitivity to both solvent polarity and pH. The azaphenanthrenoids derived from the 2- and 4-pyridyl isomers exhibit intense emission at wavelengths that exceed 500 nm under certain conditions and appear to be well suited as fluorescent probes for the estrogen receptor.

Full text of DOI:10.1021/jo9618029

J . Org. Chem. 1997, 62, 1043-1057
1043
1-Ar yl-2-p yr id yl-3,4-d ih yd r on a p h th a len es: P h otoflu or ogen ic
Liga n d s for th e Estr ogen Recep tor
Andrew W. Scribner, Serkos A. Haroutounian, Kathryn E. Carlson, and
J ohn A. Katzenellenbogen*
Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801
Received September 20, 1996X
Three 1,2-substituted-3,4-dihydronaphthalenes that are pyridine analogs of the antiestrogen
desmethylnafoxidine were prepared and evaluated as fluorescent ligands for the estrogen receptor.
These compounds represent a class of fluorescent probes that we term “photofluorogenic”, denoting
their ability to exist initially as a high affinity though weakly fluorescent stilbazole form which
can be photocyclized-oxidized to a highly fluorescent though low affinity azaphenanthrenoid form.
These probes also contain an aziridine function that provides a means for their permanent, covalent
attachment to the receptor. The three dihydronaphthalene systems were prepared by efficient
routes from R-(2-, 3-, and 4-pyridyl)acetophenone precursors. They demonstrate high apparent
affinity for the estrogen receptor and show time-dependent irreversible inactivation, consistent
with their covalent attachment to the receptor via the aziridine function. Each system is converted
into an azaphenanthrene by photocyclization-oxidation of the cis-stilbazole unit. The absorbance
and fluorescence emission spectra of the dihydronaphthalene precursors and azaphenanthrene
products have been characterized, and they display marked sensitivity to both solvent polarity
and pH. The azaphenanthrenoids derived from the 2- and 4-pyridyl isomers exhibit intense emission
at wavelengths that exceed 500 nm under certain conditions and appear to be well suited as
fluorescent probes for the estrogen receptor.
In tr od u ction
wavelengths greater than 500 nm, in order for the
fluorophore emission to be distinguishable from the
background of cell autofluorescence.6
We have been interested in the development of fluo-
rescent probes for the estrogen receptor (ER) that would
be useful in elucidating receptor structure and function
and in predicting the hormonal responsiveness of breast
cancer patients.1,2 The latter application involves mea-
suring the receptor content of individual cells using flow
cytometry3 or fluorescence microscopy4 in order to dis-
tinguish ER-positive from ER-negative cells.5 Such a
fluorescent probe should demonstrate high relative bind-
ing affinity (RBA) for the ER and exhibit fluorescence at
In earlier studies, we have developed three major
classes of fluorescent estrogenic probes (Figure 1): es-
trogen-fluorophore conjugates,7 inherently fluorescent
estrogens,8 and photofluorogenic estrogens.9 Estrogen-
fluorophore conjugates link a fluorescent moiety such as
a nitrobenzoxadiazole to an estrogen such as hexestrol
via an alkyl spacer, as seen in 1. These systems are
bulky and generally have poor affinity for the estrogen
receptor. Inherently fluorescent estrogens are fluores-
(5) (a) Silverswaard, C.; Skoog, L.; Humla, S.; Gustafsson, S. A.;
Nordensjold, B. Cancer 1980, 16, 59. (b) McCarty, K. S., J r.; Reintgen,
D. S.; Seigler, H. F. Br. Cancer Res. Treat. 1982, 1, 315. (c) McCarty,
K. S., J r.; Lubahn, D. B.; McCarty, K. S., Sr. Clin. Endocrinol. Metab.
1983, 12, 133. (d) McGuire, W. L. Estrogen Receptors in Human Breast
Cancer; Carbone, P., Vollmer, E. P., Eds.; Raven Press: New York,
1975.
(6) Waggoner, A. S. In Applications of Fluorescence in the Biomedical
Sciences; Taylor, P. L., Waggoner, A. S., Murphy, R. F., Lanni, F., Birge,
R. R., Eds.; Alan Liss: New York, 1986.
X Abstract published in Advance ACS Abstracts, February 1, 1997.
(1) Lee, Y. J .; Notides, A. C.; Tsay, Y. G.; Kende, A. S. Biochemistry
1977, 16, 2896.
(2) (a) Thorpe, S. M. Acta Oncol. 1988, 27, 1. (b) Valavaara, R.;
Touminen, J .; J ohansson, R. Cancer 1990, 66, 2264. (c) Thompson, E.
B.; Lippman, M. E. Steroid Receptors and the Management of Cancer,
vol. I; CRC Press: Boca Raton, 1979. (d) DeSombre, E. R.; Green, G.
L.; J ensen, E. V. Hormones, Receptors, and Breast Cancer; Raven
Press: New York, 1978.
(3) (a) Van, N. T.; Raber, M.; Barrows, G. H.; Barlogie, B. Science
1984, 224, 876. (b) Kute, T. E.; Linville, C.; Barrows, G. Cytometry
1983, 4, 132. (c) Oxenhandler, R. W.; McvCune, R.; Subtelney, A.;
Truelove, C.; Tyrer, H. W. Cancer Res. 1984, 44, 2516. (d) Benz, C.;
Wizner, I.; Lee, S. H. Localiztion of Putative Steroid Receptors, vol. I;
Pertschuk, P. L., Lee, S. H., Eds.; CRC Press: Boca Raton, 1985; pp
95-110.
(4) (a) Nenci, I. Cancer Res. 1978, 38, 4204. (b) Dandliker, W. B.;
Brown, R. J .; Hsu, M. L.; Brown, P. N.; Levin, J .; Meyers, C. Y.; Kolb,
V. M. Cancer Res. 1978, 38, 4212. (c) Pertschuk, L. P.; Tobin, E. H.;
Gaetjens, E.; Carter, A. C.; Degenshein, G. A.; Bloom, N. D.; Brigati,
D. J . Cancer 1980, 46, 2896. (d) Barrows, G. H.; Stroupe, S. B.; Rieh,
M. J . D. Am. J . Clin. Pathol. 1980, 73, 330. (e) J oyce, B. D.; Nicholson,
R. I.; Morton, M. S.; Griffiths, K. Eur. J . Cancer Clin. Oncol. 1982, 18,
1147. (f) Fisher, B.; Gunduz, N. Saffer, E. A. Cancer Res. 1983, 43,
5244. (g) Lee, S. H. Am. J . Clin. Pathol. 1983, 79, 484. (h) Pertschuk,
L. P.; Tobin, E. H.; Tanapat, P.; Gaetjens, E.; Carter, A. C.; Bloom, N.
D.; Macchia, R. J .; Eisenberg, K. B. J . Histochem. Cytochem. 1980,
28, 799. (i) Lee, S. H. Cancer 1979, 44, 1. (j) Martin, P. M.; Horwitz,
K. B.; Ryan, D. S.; McGuire, W. L. Endocrinology 1978, 103, 1860. (k)
Tobin, E. H.; Pertschuk, L. P.; Tanapat, P.; Brigati, D. J .; Azizi, F.;
Bloom, D. D.; Degenshein, G. A. Fed. Proc. 1980, 39, 550. (l) Pertschuk,
L. P.; Eisenberg, K. B.; Carter, A. C.; Feldman, J . G. Breast Cancer
Res. Treat. 1985, 5, 137.
(7) For examples of estrogen-fluorophore conjugates, see: (a) Fevig,
T. L.; Lloyd, J . E.; Zablocki, J . A.; Katzenellenbogen, J . A. J . Med.
Chem. 1987, 30, 156. (b) Carlson, K. E.; Coppey, M.; Magdelenat, H.;
Katzenellenbogen. J . A. J . Steroid Biochem. 1989, 32, 345. (c) French,
A. N.; Wilson, S. R.; Welch, M. J .; Katzenellenbogen, J . A. Steroids
1993, 58, 157.
(8) For examples of inherently fluorescent estrogens, see: (a) Martin,
P. M.; Magdelenat, H. P.; Benyahia, B.; Rigaud, O.; Katzenellenbogen,
J . A. Cancer Res. 1983, 43, 4956. (b) Katzenellenbogen, J . A.; Carlson,
K. E.; Bindal, R. D.; Neeley, R. L.; Martin, P. M.; Magdelenat, H. P.
Anal. Biochem. 1986, 159, 336. (c) Anstead, G. M.; Altenbach, R. J .;
Wilson, S. R.; Katzenellenbogen, J . A. J . Med. Chem. 1988, 31, 1316.
(d) Anstead, G. M.; Katzenellenbogen, J . A. J . Med. Chem. 1988, 31,
1754. (e) Anstead, G. M.; Katzenellenbogen, J . A. J . Phys. Chem. 1988,
92, 6249. (f) Anstead, G. M.; Ensign, J . L.; Peterson, C. S.; Katzenel-
lenbogen, J . A. J . Org. Chem. 1989, 54, 1485. (g) Anstead, G. M.;
Wilson, S. R.; Katzenellenbogen, J . A. J . Med. Chem. 1989, 32, 2163.
(h) Anstead, G. M.; Peterson, C. S.; Katzenellenbogen, J . A. J . Steroid
Biochem. 1989, 33, 877. (k) Miksicek, R. J .; Carlson, K. E.; Hwang,
K.-J .; Katzenellenbogen, J . A. Mol. Endocrinol. 1995, 9, 592.
(9) For examples of photofluorogenic estrogens, see: (a) Bindal, R.
D.; Katzenellenbogen, J . A. J . Steroid Biochem. 1985, 23, 929. (b)
Bindal, R. D.; Katzenellenbogen, J . A. Photochem. Photobiol. 1986, 43,
121.
S0022-3263(96)01802-6 CCC: $14.00 © 1997 American Chemical Society

1044 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
F igu r e 1. Examples of fluorescent estrogens.
cent by virtue of extended conjugation within the molec-
ular confines of an estrogenic ligand, as exhibited by 12-
oxo-9(11)-dehydroestradiol (2).8a Although the design of
these systems can entail a compromise to achieve both
good fluorescence and receptor binding within a single
molecular entity, some compounds show promising char-
acteristics, and we are currently continuing our investi-
gation of tetrahydrochrysene derivatives in this class,
such as the ketone 3.8i,j
compound, however, has low affinity for the receptor. The
behavior of its high affinity 4-hydroxy metabolite of
tamoxifen (6b) is complicated by its facile cis-trans
isomerization.13 Thus, we chose to explore derivatives
of the analogous but cyclic antiestrogen nafoxidine (4b),
whose rigid dihydronaphthalene core is inert to such
isomerization. We have reported preliminary spectro-
scopic studies on both desmethylnafoxidine (4a ) and a
related analog (7) and on the products of photocyclization,
which exhibit long wavelength fluorescence emission.9 In
related work, we explored the photocyclization of hy-
droxystilbazoles (8) to hydroxyazaphenanthrenes (9) as
model systems for photofluorogenic estrogens that give
photoproducts with wavelength-extended emission that
in some cases extends beyond 600 nm.14
In this report, we describe three new photofluorogenic
estrogens in which the 2-phenyl ring of desmethylnafoxi-
dine is replaced by a pyridine ring (Figure 2; 10-12). This
substitution leads, after photocyclization-oxidation, to
four hydroxyazaphenanthrene photoproducts (13) that
have a donor-acceptor character and show intense
fluorescence that is very sensitive to solvent pH and
polarity.14
The work described herein involves fluorescent probes
from the third class, which we have termed “photofluo-
rogenic”. As exemplified by the 1,2-diaryl-3,4-dihy-
dronaphthalene system 4a , an analog of the antiestrogen
nafoxidine (4b), these molecules exist in two distinct
forms: a parent form (4a ) that is weakly fluorescent but
has high affinity for the receptor, and a daughter form
(5) which has lower binding affinity but is strongly
fluorescent.9 This first form can be converted into the
second form upon photocyclization and oxidation. An
attractive feature of photofluorogenic probes is their
potential for achieving background correction, i.e., a cell
background fluorescence image, captured prior to pho-
tocyclization, could be stored in digitized form and then
subtracted from the fluorescence image obtained after
photochemical generation of the fluorophore (effected by
brief irradiation at a shorter wavelength and spontaneous
oxidation).10 For this purpose, we have considered the
photocyclization of hydroxy-substituted stilbene moi-
eties11 (which are present in many potent estrogens, such
as 4a b) to their corresponding hydroxyphenanthrenes,
such as 5. The antiestrogen tamoxifen (6a ) has been
used in a photofluorogenic based HPLC assay;12 this
A final consideration in the design of these photofluo-
rogenic probes involves giving them the capacity to
covalently attach to the receptor, to preclude their loss
from the ER upon photocyclization or subsequent pH
manipulation. We know from earlier studies that a
suitably positioned aziridine function will undergo an
efficient covalent reaction with a specific cysteine residue
(12) (a) Mendenhall, D. W.; Kobayashi, H.; Shih, F. M. L.; Sternson,
L. A.; Higuchi, T.; Fabian, C. Clin. Chem. 1978, 24, 1518. (b) Brown,
R. R.; Bain, R.; J ordan, V. C. J . Chromatogr. 1983, 272, 351.
(13) Katzenellenbogen, J . A.; Carlson, K. E.; Katzenellenbogen, B.
S. J . Steroid Biochem. 1985, 22, 589.
(14) Haroutounian, S. A.; Katzenellenbogen, J . A. Photochem. Pho-
tobiol. 1988, 47, 503.
(10) Katzenellenbogen, J . A. In Trends in Drug Research; Claassen,
A., Ed.; Elsevier Science Publishers, B.V.: Amsterdam, 1993; p 243.
(11) Mallory, F. B.; Mallory, C. W. In Organic Reactions; Dauben,
W. G., Ed.; J ohn Wiley & Sons Inc.: New York, 1984; Vol. 30, p 1.

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1045
F igu r e 2. New photofluorogenic estrogen aziridines (10-12) and general strategy for covalent and fluorescent labeling of the
estrogen receptor.
Sch em e 1
near the C-terminus of ER (C530 in human ER).15 This
aziridine function has been included in some of the
pyridine-substituted desmethylnafoxidine photofluoro-
genic estrogens that we have prepared. Thus, the overall
strategy for labeling ER-positive cells (Figure 2) would
involve first the incubation of the high affinity stilbazole
aziridine (10-12) to form a covalent bond with C530 of
ER. The ER-ligand complex could then be irradiated
to induce photocyclization of the stilbazole to the corre-
sponding azaphenanthrenoid 13 (after spontaneous oxi-
dation of a dihydro intermediate). The pH could then
be manipulated in order to optimize fluorescence emis-
sion.
Therefore, in this report we present the syntheses of
these three new photofluorogenic estrogen aziridines
(10-12) from monocyclic precursors, accounting for each
of the three possible sites of pyridyl nitrogen substitution,
and we describe the photocyclization of their benzyl ether
analogs to the azaphenanthrenoid products. We also
report the ER binding affinities of these aziridines and
various analogs and demonstrate the capacity of the
aziridines for covalent attachment to ER. Lastly, we
provide ultraviolet absorbance and fluorescence emission
spectral data of benzyl ether-protected derivatives of each
of the three stilbazoles and their four products of pho-
tocyclization.
Resu lts a n d Discu ssion
Ch em ica l Syn th eses. The synthetic approach we
have taken to the 1-aryl-2-pyridyl-3,4-dihydronaphtha-
lene system parallels one we have used for the prepara-
tion of 1,2-diarylindenes.8c A retrosynthetic plan is given
directly to give the ketone 17,16 found to exist as a
in Scheme 1. The route involves the synthesis of an
mixture of keto and enol tautomers, the latter due to
R-pyridylacetophenone intermediate from a picoline an-
intramolecular hydrogen bonding.16a The anions of 3-pi-
ion, R-alkylation with an activated phenethyl species, and
coline and 4-picoline, however, gave low yields in this
then Friedel-Crafts cyclodehydration to the dihydronaph-
transformation. As an alternative approach, the anions
of these picoline isomers were added to aldehyde 16 to
yield alcohols 18 and 19, which were then oxidized by
J ones reagent to afford ketones 20 and 21, for which enol
tautomers were not observed. The reduced yield for the
sequence with 3-picoline is most likely due its weaker
acidity (pKa ) 37.7) compared to either 2-picoline (pKa
) 34) or 4-picoline (pKa ) 32.2),17 whose anions are more
effectively resonance stabilized. We were unsuccessful
in improving the yield of the 3-picoline sequence with
polar additives (DMPU, HMPA), despite literature
claims.18
thalene core structure. Functional group interchange,
attachment of the aziridine function, and deprotection
completed the synthesis.
The two phenyl ether precursors (15 and 16) were
prepared (Scheme 2) by alkylation of the corresponding
phenols with 2-(benzyloxy)ethyl methanesulfonate (me-
sylate) (14), which itself was prepared by activation of
2-(benzyloxy)ethanol. Deprotonation of 2-picoline with
lithium diisopropylamide followed by addition of nitrile
15 yielded the corresponding imine, which was acidified
(15) Harlow, K. W.; Smith, D. M.; Katzenellenbogen, J . A.; Greene,
G. L.; Katzenellbogen, B. S. J . Biol. Chem. 1989, 264, 17476.
(16) (a) Konakahara, T.; Takagi, Y. Heterocycles 1980, 14, 393. (b)
Konakahara, T.; Sato, K. Bull. Chem. Soc. J pn. 1983, 56, 1241.
(17) Fraser, R. R.; Mansour, T. S.; Savard, S. J . Org. Chem. 1985,
50, 3232.

1046 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
Sch em e 2
Sch em e 4
was then protected as tetrahydropyranyl (THP) ether 25
using dihydropyran and catalytic pyridinium p-toluene-
sulfonate.20 The acid-labile THP group was used to
protect the phenol, as it is then cleaved during the
methanesulfonic acid cyclodehydration step without af-
fecting the benzyl ether. Other protecting group strate-
gies proved to be less efficient.21
The sodium salts of each of the three ketones (17, 20,
and 21) were alkylated with iodide 25 to afford products
26-28 (Scheme 4). Methanesulfonic acid-catalyzed cy-
clodehydration of the R-phenethylacetophenones,22 with
concomitant THP ether cleavage, afforded dihydronaph-
thalenes 29-31.
Sch em e 3
The remaining steps in the synthesis of the aziridines
are shown in Scheme 5. First, the phenols were protected
as aryl trifluoromethanesulfonates (triflates) 32-34.23
Benzyl ether cleavage with iodotrimethylsilane24 pro-
ceeded efficiently in the presence of at least 1 equiv of
thiophenol, which was needed to trap the benzyl iodide
and avoid pyridyl N-benzylation. Although hydrogenoly-
sis is generally a practical method for cleaving benzyl
ethers, the double bond in the dihydronaphthalene
system is prone to reduction under such conditions.21
The resulting primary alcohols 35-37 were converted
to their corresponding mesylates 38-40, which under-
went nucleophilic displacement by ethylenimine to afford
(18) (a) Kaiser, E. M.; Petty, J . D. Synthesis 1975, 705. (b) Davis,
M. L.; Wakefield, B. J .; Wardell, J . A. Tetrahedron 1992, 48, 939. (c)
Kaiser, E. M.; Petty, J . D. J . Org. Chem. 1976, 41, 716.
(19) Lednicer, D.; Lyster, S. C.; Aspergren, B. D.; Duncan, G. W. J .
Med. Chem. 1966, 9, 172.
(20) Miyashita, N.; Yoshikoshi, A.; Grieco, P. A. J . Org. Chem. 1977,
42, 3772.
(21) Simpson, D. M. Ph.D. Thesis, University of Illinois at
UrbanasChampaign, 1986.
(22) Leon, A. A.; Daub, G.; Silverman, I. R. J . Org. Chem. 1984, 49,
4544.
(23) Stang, P. J .; Hanack, M.; Subramanian, L. R. Synthesis 1982,
85.
(24) (a) J ung, M. E.; Lyster, M. A. J . Org. Chem. 1977, 42, 3761. (b)
Olah, G. A.; Narang, S. C.; Gupta, B. G. B.; Malhotra, R. J . Org. Chem.
1979, 44, 1247.
To form the dihydronaphthalene skeleton, the three
pyridyl acetophenones (17, 20, and 21) were alkylated
with the phenylethyl iodide 25. This agent 25 was
prepared in four steps from commercially available (3-
methoxyphenyl)acetic acid (Scheme 3).19 Lithium alu-
minum hydride reduction afforded primary alcohol 22,
which was then activated to mesylate 23.19 Simultaneous
iodination of the mesylate and cleavage of the methyl
ether by iodotrimethylsilane yielded phenol 24, which

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1047
Sch em e 5
Sch em e 6
Ta ble 1. Rela tive Bin d in g Affin ities of
Desm eth yln a foxid in e An a logsa
aziridines 41-43.21 Ethylenimine itself was prepared by
flash distillation of 2-aminoethyl hydrogen sulfate in
concentrated sodium hydroxide.25 The triflates were then
cleaved by lithium aluminum hydride treatment to
produce the desired phenolic aziridines 10-12.26
R
Ar
compound
RBA
H
H
H
H
phenyl
52
NA
50
NA
83
2-pyridyl
3-pyridyl
4-pyridyl
phenyl
2-pyridyl
3-pyridyl
4-pyridyl
phenyl
2-pyridyl
3-pyridyl
4-pyridyl
phenyl
2-pyridyl
3-pyridyl
4-pyridyl
53b
54
55b
5621
29
CH2CH2OBn
CH2CH2OBn
CH2CH2OBn
CH2CH2OBn
CH2CH2OH
CH2CH2OH
CH2CH2OH
CH2CH2OH
CH2CH2N(CH2)2
CH2CH2N(CH2)2
CH2CH2N(CH2)2
CH2CH2N(CH2)2
7
We prepared the four azaphenanthrenes (48-51) by
photocyclization (Scheme 6). Cyclohexane was found to
be the best solvent to carry out the photocyclizations of
stilbazoles.14 However, since phenols 29-31 exhibited
poor solubility in cyclohexane, we found it to be more
convenient to photocyclize aryl triflates 32-34 to their
corresponding azaphenanthrenoid products (44-47) and
then deprotect them to phenols 48-51. The 2- and
4-pyridyl stilbazoles 32 and 34 each photocyclized to the
single azaphenanthrenoid products 44 and 47, respec-
tively, whereas 3-pyridyl stilbazole 33 photocyclized to
an approximately 1:1 mixture of the two azaphenan-
threnoid isomers 45 and 46, despite claims of other
product ratios in related systems.11 In the case of
2-pyridyl stilbazole 32, no quaternary pyridinium salt
was formed, which is consistent with previous studies.11
Bioch em ica l Stu d ies. Estr ogen Recep tor Rela -
tive Bin d in g Affin ities. The ER relative binding
affinities (RBAs) of the three pyridyl aziridines, along
with various deprotected intermediates and previously
7.8
4.3
16.5
82
30
31
5721
58c
59c
60c
6121
10
6.4
3.5
17
79d
27d
47d
62d
11
12
a
Determined by a radiometric competitive binding assay as
previously described.27 Values represent the mean of duplicate
determinations in separate assays. The coefficient of variation of
b
these values is 0.3. Prepared by treating bis-aryl methyl ether
precursors with boron trifluoride-dimethyl sulfide complex. c Pre-
pared by treating compounds 35-37 with lithium aluminum
d
hydride. Apparent relative binding affinities (see text for expla-
nation).
prepared analogs,21 are shown in Table 1. These values
were obtained from a competitive binding assay with [3H]-
estradiol as a tracer using dextran-coated charcoal to
adsorb free ligand,27 and they are expressed in percent,
(25) Reeves, W.; Drake, G.; Hoffpauir, C. J . Am. Chem. Soc. 1951,
73, 3522.
(26) Hwang, K.-J . Ph.D. Thesis, University of Illinois at
UrbanasChampaign, 1991.
(27) Katzenellenbogen, J . A.; J ohnson, H. J ., J r.; Myers, H. N.
Biochemistry 1973, 12, 4085.

1048 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
F igu r e 3. Rate of inactivation of estrogen receptor by aziridines 10-12. Data are expressed as a percentage of initial estrogen-
specific binding site concentration.28 The dotted line represents incubation with estradiol alone, the dashed line incubation with
estradiol plus aziridine, and the solid line aziridine alone. Panel A, aziridine 10; panel B, aziridine 11; panel C, aziridine 12. For
details, see Experimental Section and ref 28.
Ta ble 2. Rela tive Bin d in g Affin ities of P h otocyclized
affinities of these azaphenanthrenoid species (48-51) are
considerably lower than those of their stilbazole coun-
Desm eth yln a foxid in e An a logsa
terparts (29-31) shown in Table 1, again with the
4-pyridyl-derived isomer (50) having greater affinity than
any of its isomers (48, 49, and 51).
E st r ogen R ecep t or In a ct iva t ion Assa y. Each of
the three aziridines (10-12) were tested for their ability
to covalently attach to the ER by a time-dependent
receptor inactivation assay.28 This was done by incubat-
ing each compound with ER, then assaying remaining
ER binding sites by an exchange assay with [3H]estradiol
N position
compound
RBA
at various time points. Data for compounds 10-12 are
shown in Figures 3A-C, respectively. Although each
aziridine did not necessarily behave identically, all three
inactivated ER by over 90% within 1 h, and 95% within
2 h.
Sp ectr oscop ic Stu d ies. Ultraviolet absorbance of
the seven phenols 29-31 and 48-51 was measured in
tetrahydrofuran, acetonitrile, ethanol, and water under
neutral and acidic (0.1 N HCl) conditions. Spectra in the
latter three solvents were also obtained under basic (0.1
N KOH) conditions; THF was excluded from studies in
base due to solubility problems. The fluorescence emis-
sion of each compound was then obtained with the same
four solvents and at the same three pHs, using the major
long-wavelength absorbance maximum as the excitation
wavelength.
Table 3 displays wavelengths of maximum absorbance
of the three stilbazoles (29-31), and selected spectra are
shown in Figure 4. Under neutral conditions, all three
compounds have absorbance maxima at ∼330 nm, with
the 4-pyridyl (∼335 nm) and 2-pyridyl (∼329 nm) isomers
absorbing at somewhat longer wavelengths than the
3-pyridyl isomer (∼318 nm). Substantial bathochromic
shifts are observed in both acid and base, particularly in
organic solvents. In base, all three isomers displayed a
pronounced bathochromic shift with the same relative
order of wavelengths of maximum absorption among the
2
3
4
3′
48
49
50
51
0.040
0.042
0.26
0.10
a
Determined by a radiometric competitive binding assay as
previously described.27 Values represent the mean of duplicate
determinations in separate assays. The coefficient of variation of
these values is 0.3.
with estradiol having an affinity of 100%. All three
aziridines (10-12) display appreciable apparent affinity
for the estrogen receptor.15 Although the values vary, it
is difficult to conclude whether or not the location of the
pyridyl nitrogen has an influence on receptor binding,
as the coefficient of variation in RBA measurements is
0.3. Also, it should be emphasized that the aziridines
bind irreversibly to the receptor; therefore, the measured
affinity is not the result of a true competition and thus
is termed “apparent”.15
As for other intermediates, the bis-phenols 53 and 55
are among the highest affinity. In the hydroxyethyl ether
series (57-60), the pyridyl-substituted desmethylafoxi-
dine analogs (58-60) have considerably lower affinity
than the phenyl-substituted one (57), whereas in the
(benzyloxy)ethyl ether series (29-31, 56), the binding
affinities of the pyridyl (29-31) vs phenyl-substituted
(56) analogs are more comparable. Within a given series,
however, the 4-pyridyl species consistently has higher
affinity than either its 2- or 3-pyridyl-substituted isomers
(compare 31 vs 29 and 30; 60 vs 58 and 59).
(28) Robertson, D. W.; Wei, L. L.; Hayes, J . R.; Carlson, K. E.;
Katzenellenbogen, J . A.; Katzenellenbogen, B. S. Endocrinology 1981,
109, 1298.
Table 2 provides the RBAs of photocyclized desmeth-
ylnafoxidine analogs. Here it is seen that binding

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1049
Ta ble 3. Lon g Wa velen gth Ma xim a of Ultr a violet Absor ba n ce of Desm eth yln a foxid in e An a logs
absorbance λmax (ꢀ)
compound
conditiona
THF
CH3CN
EtOH
H2O
29
neutral
acidic
basic
neutral
acidic
basic
neutral
acidic
basic
328 (21 000)
390 (17 800)
-
316 (17 100)
334 (12 900)
-
328 (16 500)
396 (20 500)
-
320 (17 900)
388 (16 600)
386 (21 700)
312 (13 900)
360 (19 400)
374 (17 500)
335 (15 000)
402 (16 600)
394 (21 600)
330 (17 000)
396 (18 300)
366 (21 800)
320 (14 600)
342 (12 200)
364 (18 800)
336 (15 700)
412 (18 300)
380 (21 400)
336 (15 200)
376 (12 500)
344 (15 300)
324 (12 400)
318 (10 200)
332 (14 200)
346 (13 300)
388 (14 100)
356 (16 400)
30
31
a
Acidic ) 0.1 N HCl prepared by adding concd HCl; basic ) 0.1 N KOH prepared by adding 6 N KOH.
three isomers (4-pyridyl ∼387 nm, 2-pyridyl ∼376 nm,
3-pyridyl ∼369 nm); in acid, however, the 2- and 4-pyridyl
isomers displayed a considerable bathochromic shift (to
∼403 nm and ∼391 nm, respectively), whereas the
3-pyridyl isomer (to ∼345 nm) showed merely a broaden-
ing of the peak. The most discernible solvatochromic
trend was a hypsochromic shift in base with an increase
in solvent polarity. Shifts in absorbance maxima in
neutral and acidic media, on the other hand, were
relatively modest. Overall, the trends observed in these
spectra correlated reasonably well with those of the
unsubstituted stilbazoles previously reported.14
and pH conditions; in each case, wavelengths of maxi-
mum emission were measured, along with quantum
yields, which were calculated by the method of Olmsted,
using Coumarin I in ethanol (320-410 nm), acridine
yellow in methanol (410-480 nm), and quinine sulfate
in 1.0 N H2SO4 (280-380 nm) as standards.29 Table 5
shows the fluorescence data of the three stilbazoles (29-
31). As expected, the fluorescence emission is extremely
weak because the 1- and 2-aryl rings are twisted out of
planarity from one another.
The fluorescence emission of azaphenanthrenes 48-
51 are reported in Table 6, and selected spectra are
illustrated in Figure 6. As with the absorbance spectra,
bathochromic shifts occurred in both acid and base. In
acid, the 4-pyridyl-derived isomer (50) was red-shifted
the least of the four isomers (to 482-499 nm), but emitted
with the greatest quantum yield (0.65-0.82), greater
than what was observed in neutral conditions (0.42-
0.69). Reasonably strong quantum yields (0.10-0.24)
were observed for compound 50 in base as well, where
wavelength maxima were red-shifted to 533-570 nm.
The 2-pyridyl-derived isomer (48), on the other hand, was
red-shifted up to 535-550 nm in acid, but emitted with
weaker quantum yields (0.042-0.058) than those ob-
served in neutral solvent (0.18-0.29). In addition,
compound 48 displayed very weak fluorescence emission
in base. The 3-pyridyl-derived isomers (49 and 51),
however, displayed extremely weak fluorescence in both
acid and base.
The wavelengths of maximum absorbance of the four
azaphenanthrenes (48-51) are shown in Table 4, and
selected spectra are shown in Figure 5. The absorbance
spectra for these rigid compounds are considerably more
complex than those of the corresponding stilbazoles;
however, some trends are similar. Once again, the most
striking observation is the bathochromic shift shown by
all compounds in all solvents when going from neutral
media (334-362 nm) to acidic (418-442 nm) or basic
(356-406 nm) media. In base, all compounds exhibited
a pronounced bathochromic shift that is most pronounced
for the 4-pyridyl-derived system (50). In acid, the 2- and
4-pyridyl-derived isomers (48 and 50) exhibited substan-
tial red-shifted absorbances with high molar absorptivi-
ties (ꢀ ) 10 100-18 300 M-1 cm-1), whereas both 3-pyridyl-
derived isomers (49-51) were also red-shifted, but
exhibited rather weak absorbances in this range (ꢀ )
2900-3900 M-1 cm-1).
The same solvatochromic trends were observed with
these azaphenanthrenes as with the stilbazoles. As
solvent polarity increased, a distinct hypsochromic shift
was observed in base in all cases, while bathochromic
shifts occurred in neutral conditions. The profound
distinction between the 2- and 4-pyridyl-derived isomers
from the two 3-pyridyl-derived isomers in acidic media
with regard to intensity of longest wavelength of absor-
bance was not apparent in our previous studies of
unsubstituted azaphenanthrenes.14
In addition to being responsive to pH, each compound
displayed sensitivity to solvent polarity. In neutral
solvents, a distinct bathochromic shift occurred with an
increase in solvent polarity. It is difficult, however, to
conclude what solvatochromic trends were exhibited in
acid and base, due to the weak intensities of emission
under these conditions. A final note concerns the pro-
found quenching effect of water. Although some wave-
length maxima appear considerably red-shifted in water,
they are difficult to observe because of their weak
intensities. The only exception to this is 4-pyridyl-
Fluorescence emission of each of the seven phenols was
then measured in each of the aforementioned solvents
(29) Olmsted, J ., III. J . Phys. Chem. 1979, 83, 2581.

1050 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
excited state due to increased acidity and basicity of the
phenol and pyridyl rings, respectively. This phenom-
enon, however, was not apparent in our present study.
Con clu sion
We have prepared three isomeric pyridine-substituted
analogs of desmethylnafoxidine as potential photofluo-
rogenic probes for the estrogen receptor (ER). Each
isomer possesses an aziridyl ring to covalently bind to
ER, and a pyridyl ring within a stilbazole moiety, which
can be photocyclized to one of four fluorescent aza-
phenanthrenoids after covalent attachment. All three
aziridines prepared (10-12) were found to have high
apparent binding affinity for ER, and were also shown
to bind covalently to ER. Spectroscopic studies of inter-
mediates (29-31, 48-51) have shown that the 2- and
4-pyridyl isomers appear the most promising. While each
of the four azaphenanthrenes (48-51) displayed strong
sensitivity to both solvent polarity and pH, only the 2-
and 4-pyridyl-derived isomers (48 and 50, respectively)
exhibited appreciable quantum yields in acid and base,
at wavelengths greater than or equal to 500 nm.
Future work entails optimizing the conditions for the
photocyclization of these compounds once they are co-
valently bound to the estrogen receptor and studying
their fluorescence properties in whole cells. Ultimately,
we hope to use these compounds to aid both in ER
structural elucidation and in breast tumor cell ER
content measurements.
Exp er im en ta l Section
Gen er a l. All reagents and solvents were obtained from
Aldrich, Mallinckrodt, EM Science, and Burdick and J ackson.
Tetrahydrofuran was distilled from sodium/benzophenone.
Diisopropylamine, triethylamine, and methylene chloride were
distilled from calcium hydride. Dimethylformamide was
vacuum-distilled over magnesium sulfate and stored over 4 Å
molecular sieves. Hexane was distilled prior to chromato-
graphic use. n-Butyllithium (∼1.6 M in hexane) was titrated
with diphenylacetic acid. All reactions were performed under
a dry N2 atmosphere unless specified otherwise.30 Reaction
progress was monitored by analytical thin-layer chromatog-
raphy, performed with 0.25 mm silica gel glass plates contain-
ing F-254 indicator (Merck). Visualization on TLC was
achieved by either UV light (254 nm, 350 nm) or phosphomo-
lybdic acid indicator. Flash chromatography31 was performed
with Woelm 32-63 µm silica gel packing. HPLC purification
was performed on a Whatman Partisil M9 10/50 ODS-2 reverse
phase column.
Fluorescence spectra were recorded by photon counting on
a Spex Fluorolog 2 Spectrophotometer (Model FL111) with
DM3000 software. Samples were prepared from stock solu-
tions (∼10-3 M) of the corresponding compounds in ethanol
giving final concentrations of ∼5 × 10-6 M. Acidic and basic
solutions were prepared by addition of an amount of concen-
trated HCl or 6 N KOH solution in water, calculated to give a
0.1 N solution. All spectra were recorded at room temperature
with 0.50 mm slits. All emission spectra are corrected, and
solvent background is subtracted. Irradiations were conducted
in a Rayonet photochemical reactor (RPR-100) fitted with 16
8 W lamps emitting 300 nm wavelength. Reactions took place
in a water-cooled quartz vessel. Proton magnetic resonance
spectra (200 MHz or 400 MHz) were recorded with chemical
shifts reported as parts per million downfield from an internal
tetramethylsilane standard.
F igu r e 4. Ultraviolet spectra of dihydronaphthalenes 29-
31 in EtOH. All spectra were obtained at the same concen-
traiton (5 × 10-6 M) in EtOH (neutral), or EtOH with 0.1 N
HCl (acidic) or 0.1 N KOH (basic).
derived isomer 50, which was the only isomer found to
exhibit appreciable quantum yields in water, specifically,
under both acidic and basic conditions (0.079 and 0.012,
respectively).
In summary, the greatest distinction between the
compounds studied with regard to both ultraviolet ab-
sorbance and fluorescence emission appears to exist
between the resonance reinforced 2- and 4-pyridyl-
derived isomers and the non-resonance-reinforced 3-py-
ridyl-derived isomers (Figure 7). Whereas one can draw
resonance forms for the 2- and 4-pyridyl-derived isomers
in which the positive charge on the phenolic ring oxygen
can be compensated by negative charge localization on
the nitrogen, one cannot draw such resonance forms with
any of the 3-pyridyl stilbazoles or azaphenanthrenes.
This electronic contribution to absorbance and emission
appears to supersede all others, particularly for com-
pound 50 in water.
A final comment is made concerning dual fluorescence.
In our previous investigation,14 we observed that the
4-pyridyl-derived azaphenanthrene exhibited dual fluo-
rescence in protic solvent at any pH, presumably due to
a zwitterionic phototautomer which can exist only in the
Compounds 22 and 23 were prepared as described by
Lednicer.19 Ethyleneimine was prepared as described by
(30) Kofron, W. G.; Baclawski, L. M. J . Org. Chem. 1976, 41, 1879.
(31) Still, W. C.; Kahn, M.; Mitra, A. J . Org. Chem. 1978, 43, 2923.

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1051
Ta ble 4. Lon g Wa velen gth Ma xim a of Ultr a violet Absor ba n ce of P h otocyclized Desm eth yln a foxid in e An a logs
absorbance λmax (ꢀ)
compound
conditiona
THF
CH3CN
EtOH
H2O
48
neutral
acidic
basic
neutral
acidic
basic
neutral
acidic
basic
neutral
acidic
basic
342 (17 700)
430 (11 900)
-
344 (14 700)
432 (3 900)
-
346 (14 700)
418 (18 300)
-
340 (14 300)
432 (2 900)
-
342 (15 200)
432 (10 100)
396 (18 000)
334 (12 500)
434 (2 830)
384 (31 000)
346 (12 400)
420 (15 800)
406 (24 600)
340 (12 600)
438 (3 480)
386 (27 800)
346 (14 900)
440 (11 500)
370 (19 800)
342 (13 500)
442 (3 350)
370 (17 000)
356 (13 400)
426 (17 700)
396 (20 200)
346 (13 800)
436 (2 840)
370 (18 100)
350 (10 600)
424 (6 610)
360 (15 400)
346 (9 810)
430 (2 460)
356 (13 600)
362 (9 310)
412 (10 200)
382 (15 100)
348 (7 650)
428 (1 730)
358 (14 500)
49
50
51
a
Acidic ) 0.1 N HCl prepared by adding concd HCl; basic ) 0.1 N KOH prepared by adding 6 N KOH.
Reeves.25 Ca u tion a r y Note: Ethylenimine is volatile, reactive,
carcinogenic, and acutely toxic.32 All manipulations involved
in its preparation, purification, and use should be performed
in a well ventilated fume hood, providing protection against
explosion. The ammonia-like odor threshold is reported as 2
ppm, but a threshold limit of 0.5 ppm in air for continuous
exposure has been set.
(1.16 g, 8.39 mmol) in 100 mL of 2-butanone. 1H NMR (400
MHz, CDCl3) δ 3.84 (m, 2H), 4.18 (m, 2H), 4.63 (s, 2H), 6.97
(d, J ) 9.0 Hz, 2H), 7.36 (m, 5H), 7.54 (d, J ) 9.0 Hz, 2H); MS
(EI, 70 eV) m/ z (relative intensity) 253 (M+, 8), 119 (7), 105
(8), 91 (100), 77 (4), 70 (14), 61 (90), 51 (4), 43 (33). Anal. Calcd
for C16H15NO2: C, 75.87; H, 5.97; N, 5.53. Found: C, 75.70;
H, 5.94; N, 5.40.
In most cases, a general procedure for product isolation and
purification was utilized that involved quenching the reaction
in an aqueous solution, exhaustive extraction in an organic
solvent, drying over an anhydrous salt, filtration, evaporation
under reduced pressure, and flash chromatography. In the
experimental descriptions this is indicated by the phrase
“product isolation” (which is then followed, in parentheses, by
a listing of quenching agent, extraction solvent, drying agent
if not Na2SO4, which is not listed) and “purification” (which is
followed, in parenthesis, by the elution solvent used in the
flash chromatography).
4-[2-(Ben zyloxy)eth oxy]ben zaldeh yde (16). Product iso-
lation and purification (1:4 EtOAc:hexane) afforded 16 as a
colorless oil (8.92 g, 85%), prepared from 4-hydroxybenzalde-
hyde (5.00 g, 40.9 mmol), mesylate 14 (9.72 g, 49.0 mmol), and
K2CO3 (28.3 g, 205 mmol) in 250 mL of 2-butanone. 1H NMR
(400 MHz, CDCl3) δ 3.86 (m, 2H), 4.23 (m, 2H), 4.64 (s, 2H),
7.03 (d, J ) 8.8 Hz, 2H), 7.36 (m, 5H), 7.83 (d, J ) 8.8 Hz,
2H), 9.89 (s, 1H); MS (EI, 70 eV) m/ z (relative intensity) 256
(M+, 3), 150 (7), 122 (8), 105 (12), 91 (100), 77 (9), 65 (11), 51
(6), 40 (6). Anal. Calcd for C16H16O3: C, 74.98; H, 6.29.
Found: C, 74.94; H, 6.35.
2-(Ben zyloxy)eth yl Meth a n esu lfon a te (14). To a solu-
tion of 2-(benzyloxy)ethanol (2.00 g, 13.1 mmol) dissolved in
100 mL of THF at 0 °C was added dropwise first Et3N (1.99 g,
19.7 mmol) followed by MsCl (2.26 g, 19.7 mmol). The reaction
mixture was warmed to room temperature and stirred for an
additional 30 min. Product isolation (1 M NaHCO3, EtOAc)
and purification (1:1 EtOAc:hexane) yielded mesylate 14 as a
colorless oil (2.98 g, 98%). 1H NMR (400 MHz, CDCl3) δ 3.04
(s, 3H), 3.75 (m, 2H, 4.40 (m, 2H), 4.58 (s, 2H), 7.34 (m, 5H);
MS (EI, 70 eV) m/ z (relative intensity) 230 (M+, 3), 123 (3),
107 (37), 91 (100), 79 (12), 65 (15), 51 (5), 40 (7). Anal. Calcd
for C10H14O4S: C, 52.16; H, 6.13; S, 13.92. Found: C, 52.08;
H, 6.19; S, 13.89.
Gen er a l P r oced u r e for Alk yla tion of P h en ols. To a
stirred solution of 1.0 equiv of phenol in 2-butanone was added
5.0 equiv of K2CO3 and 1.2 equiv of mesylate 14. The reaction
mixture was mechanically stirred and heated to 80 °C for 72
h. Product isolation (H2O, EtOAc) and purification yielded the
desired aryl ether.
Gen er a l P r oced u r e for P icolin e Ad d ition s. To a stirred
solution of THF cooled to -78 °C was added 1.0-1.2 equiv of
diisopropylamine, followed by the dropwise addition of 1.0-
1.2 equiv of n-butyllithium (not exceeding the quantity of
diisopropylamine). The solution was stirred for 10 min,
allowed to warm to room temperature for 10 min, and then
recooled to -78 °C for an additional 10 min. This was followed
by the dropwise addition of 1.0-1.2 equiv of the appropriate
picoline isomer. The reaction mixture was allowed to warm
to room temperature while stirring continued for 1 h. Drop-
wise addition of 1.0 equiv of appropriate aldehyde then
followed, and stirring was continued at room temperature for
the specified time. Product isolation (1 M NaHCO3, EtOAc)
and purification yielded the desired product.
4′-[2-(Ben zyloxy)et h oxy]-2-(2-p yr id yl)a cet op h en on e
(17). Lithium diisopropylamide was prepared as described
above from diisopropylamine (3.08 g, 30.5 mmol) and n-
butyllithium (23.4 mL of 1.30 M in hexane, 30.5 mmol) in 250
mL of THF. The subsequent addition followed as described
above using 2-picoline (2.84 g, 30.5 mmol) and nitrile 15 (6.43
g, 25.4 mmol), and the mixture was stirred for 3 h. Upon
concentration of organic extracts, the resulting imine was
hydrolyzed with 2 N HCl for 10 min. Product isolation (2 M
NaOH, EtOAc) and purification (1:1 EtOAc:hexane) yielded a
yellow solid (7.74 g, 88%) as a mixture of keto and enol
tautomers. 1H NMR of keto tautomer (400 MHz, CDCl3) δ 3.85
4-[2-(Ben zyloxy)eth oxy]ben zon itr ile (15). Product iso-
lation and purification (1:4 EtOAc:hexane) afforded 15 as a
colorless oil (370 mg, 87%), prepared from 4-cyanophenol (200
mg, 1.68 mmol), mesylate 14 (463 mg, 2.01 mmol), and K2CO3
(32) Dermer, O.; Ham, G. Ethylenimine and Other Aziridines;
Academic Press: New York, 1969.

1052 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
isolation (1 M NaHCO3, EtOAc) and purification (1:2 CH2Cl2)
1
afforded 18 as a white solid (1.92 g, 29%). Mp 72-74 °C; H
NMR (400 MHz, CDCl3) δ 3.00 (m, 2H), 3.82 (m, 2H), 4.13 (m,
2H), 4.63 (s, 2H), 4.83 (dd, J ) 7.6, 5.6 Hz, 1H), 6.88 (d, J )
8.7 Hz, 2H), 7.13 (m, 1H), 7.20 (d, J ) 8.7 Hz, 2H), 7.30-7.37
(m, 5H), 7.42 (d, J ) 7.8 Hz, 1H), 8.35 (s, 1H), 8.41 (m, 1H);
MS (EI, 70 eV) m/ z (relative intensity) 349 (M+, off-scale), 257
(15), 123 (3), 105 (5), 91 (100), 77 (6), 65 (9), 39 (5). Anal. Calcd
for C22H23NO3: C, 75.62; H, 6.63; N, 4.01. Found: C, 75.65;
H, 6.66; N, 4.01.
E t h a n ol, 1-[4-[2-(Ben zyloxy)et h oxy]p h en yl]-2-(4-p y-
r id yl)-, (R,S)- (19). Alcohol 19 was prepared from 917 mg
(9.06 mmol) of diisopropylamine, 6.60 mL of 1.30 M n-
butyllithium (8.58 mmol), 799 mg (8.58 mmol) of 4-picoline,
and 2.00 g (7.80 mmol) of aldehyde 16 in 100 mL of THF. After
stirring for 12 h, product isolation (1 M NaHCO3, EtOAc) and
purification (1:2 acetone:methylene chloride) afforded alcohol
19 as a white solid (1.97 g, 73% yield). Mp 83-85 °C; 1H NMR
(400 MHz, CDCl3) δ 3.03 (m, 2H), 3.83 (m, 2H), 4.15 (m, 2H),
4.64 (s, 2H), 4.90 (dd, J ) 7.6, 5.4 Hz, 1H), 6.89 (d, J ) 8.7
Hz, 2H), 7.13 (d, J ) 5.9 Hz, 2H), 7.20 (d, J ) 8.7 Hz, 2H),
7.30-7.37 (m, 5H), 8.48 (m, 2H); MS (EI, 70 eV) m/ z (relative
intensity) 349 (M+, 2), 257 (17), 123 (3), 105 (4), 91 (100), 77
(5), 65 (9), 40 (4). Anal. Calcd for C22H23NO3: C, 75.62; H,
6.63; N, 4.01. Found: C, 75.30; H, 6.71; N, 4.07.
Gen er a l P r oced u r e for Oxid a tion of Secon d a r y Alco-
h ols. To a solution of the alcohol in acetone at -15 °C (CCl4/
dry ice) was added J ones reagent (∼10 mL per gram of alcohol).
J ones reagent was prepared from 23.5 g of CrO3 dissolved in
21 mL of concd H2SO4 with cooling and then diluted with
distilled water to give a total volume of 175 mL. After 15 min,
product isolation (1 M Na2CO3, EtOAc) and purification gave
the desired ketone.
4′-[2-(Ben zyloxy)et h oxy]-2-(3-p yr id yl)a cet op h en on e
(20). Ketone 20 was prepared from 1.53 g (4.38 mmol) of
alcohol 18 and 15 mL of J ones reagent in 150 mL of acetone.
Product isolation and purification (1:2 acetone:CH2Cl2) af-
forded 1.27 g (84%) of ketone 20 as a white solid. Mp 49-51
1
°C; H NMR (400 MHz, CDCl3) δ 3.86 (m, 2H), 4.22 (m, 2H),
4.26 (s, 2H), 4.64 (s, 2H), 6.98 (d, J ) 9.0 Hz, 2H), 7.35 (m,
6H), 7.64 (m, 1H), 7.99 (d, J ) 9.0 Hz, 2H), 8.53 (m, 2H); MS
(EI, 70 eV) m/ z (relative intensity) 347 (M+, off-scale), 319
(14), 255 (12), 150 (5), 122 (6), 105 (12), 91 (100), 77 (11), 65
(15), 57 (25), 43 (22). Anal. Calcd for C22H21NO3: C, 76.06;
H, 6.09; N, 4.03. Found: C, 75.86; H, 6.04; N, 4.04.
4′-[2-(Ben zyloxy)et h oxy]-2-(4-p yr id yl)a cet op h en on e
(21). Ketone 21 was prepared from 1.00 g (2.86 mmol) of
alcohol 19 and 10 mL of J ones reagent in 100 mL of acetone.
Product isolation and purification (1:2 acetone:CH2Cl2) af-
forded 932 mg (94%) of ketone 21 as a white solid. Mp 68-70
1
°C; H NMR (400 MHz, CDCl3) δ 3.85 (m, 2H), 4.22 (m, 2H),
4.25 (s, 2H), 4.64 (s, 2H), 6.98 (d, J ) 9.0 Hz, 2H), 7.24 (d, J
) 5.1 Hz, 2H), 7.36 (m, 5H), 7.97 (d, J ) 9.0 Hz, 2H), 8.57 (m,
2H); MS (EI, 70 eV) m/ z (relative intensity) 347 (M+, off-scale),
269 (1), 255 (36), 149 (11), 121 (9), 105 (9), 91 (100), 77 (6), 65
(10), 51 (3), 40 (5). Anal. Calcd for C22H21NO3: C, 76.06; H,
6.09; N, 4.03. Found: C, 75.86; H, 6.18; N, 4.00.
3-Hyd r oxyp h en eth yl Iod id e (24). To a solution of me-
sylate 23 (2.06 g, 8.93 mmol) in 25 mL of CH2Cl2 was added
iodotrimethylsilane (5.57 g, 35.7 mmol). After stirring for 20
h at room temperature, product isolation (saturated Na2S2O3,
CH2Cl2) and purification (1:4 EtOAc:hexane) provided phenolic
iodide 24 as a white solid (1.70 g, 77%). Mp 54-56 °C; 1H
NMR (400 MHz, CDCl3) δ 3.13 (t, J ) 7.8 Hz, 2H), 3.34 (t, J
) 7.8 Hz, 2H), 4.76 (s, 1H, -OH), 6.68 (s, 1H), 6.75 (m, 2H),
7.18 (t, J ) 7.8 Hz, 1H); MS (EI, 70 eV) m/ z (relative intensity)
248 (M+, 12), 121 (100), 103 (21), 91 (22), 77 (30), 65 (12), 51
(6), 43 (41). Anal. Calcd for C8H9IO: C, 38.74; H, 3.66; I,
51.16. Found: C, 38.70; H, 3.67; I, 51.01.
F igu r e 5. Ultraviolet spectra of azaphenanthrenoids 48-51.
All spectra were obtained at the same concentraiton (5 × 10-6
M) in EtOH (neutral), or EtOH with 0.1 N HCl (acidic) or 0.1
N KOH (basic).
(m, 2H), 4.20 (m, 2H), 4.45 (s, 2H), 4.63 (s, 2H), 6.95 (d, J )
9.0 Hz, 2H), 7.17 (m, 1H), 7.30-7.36 (m, 6H), 7.79 (d, J ) 9.0
Hz, 1H), 8.04 (d, J ) 9.0 Hz, 2H), 8.55 (m, 1H,); MS (EI, 70
eV) m/ z (relative intensity) 347 (M+, 2), 319 (4), 255 (14), 121
(5), 105 (7), 91 (100), 77 (4), 65 (11), 51 (3), 40 (5). Anal. Calcd
for C22H21NO3: C, 76.06; H, 6.09; N, 4.03. Found: C, 76.04;
H, 6.10; N, 4.02.
E t h a n ol, 1-[4-[2-(Ben zyloxy)et h oxy]p h en yl]-2-(3-p y-
r id yl)-, (R,S)- (18). Alcohol 18 was prepared from 2.05 g (20.3
mmol) of diisopropylamine, 13.4 mL of 1.41 M n-butyllithium,
1.76 g (18.9 mmol) of 3-picoline, and 4.85 g (18.9 mmol) of
aldehyde 16 in 250 mL of THF. After stirring for 12 h, product
3-(Tetr a h yd r op yr a n -2-yloxy)p h en eth yl Iod id e (25). To
a solution of phenol 24 (1.38 g, 5.58 mmol) dissolved in 5 mL
of CH2Cl2 at 0 °C were added dihydropyran (0.939 g, 11.2
mmol) and
a catalytic amount of pyridinium p-toluene-
sulfonate. The reaction was allowed to warm to room tem-
perature and stir for 2 h. Product isolation (1 M NaHCO3,
CH2Cl2) and purification (1:4 EtOAc:hexane) yielded tetrahy-

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1053
Ta ble 5. F lu or escen ce Em ission Ma xim a of Desm eth yln a foxid in e An a logs
emission λmax (ΦF)
CH3CN
compound
conditiona
THF
EtOH
H2O
29
neutral
acidic
basic
neutral
acidic
basic
neutral
acidic
basic
425 (0.0037)
516 (0.0006)
-
425 (0.0021)
518 (0.0038)
-
404 (0.0059)
501 (0.0017)
-
423 (0.0009)
516 (0.0005)
520 (0.0003)
427 (0.0007)
563 (0.0001)
503 (0.0003)
430 (0.0005)
533 (0.0008)
541 (0.0005)
426 (0.0009)
508 (0.0009)
490 (0.0013)
498 (0.0027)
557 (0.0003)
486 (0.0001)
428 (0.0012)
530 (0.0012)
515 (0.0013)
432 (0.0015)
517 (0.0006)
502 (0.0006)
431 (0.0018)
425 (0.0005)
485 (0.0004)
498 (0.0004)
525 (0.0009)
539 (0.0008)
30
31
a
b
Acidic ) 0.1 N HCl prepared by adding concd HCl; basic ) 0.1 N KOH prepared by adding 6 N KOH. ΦF Calculated using Coumarin
I in ethanol, quinine sulfate in 1.0 N H2SO4, or acridine yellow in methanol as standards.
Ta ble 6. F lu or escen ce Em ission Ma xim a of P h otocyclized Desm eth yln a foxid in e An a logs
emission λmax (ΦF)
compound
conditiona
THF
CH3CN
EtOH
H2O
48
neutral
acidic
basic
neutral
acidic
basic
neutral
acidic
basic
neutral
acidic
basic
419 (0.2311)
535 (0.0578)
-
419 (0.3217)
524 (0.0150)
-
402 (0.4199)
482 (0.7046)
-
420 (0.2817)
548 (0.0143)
-
422 (0.1800)
550 (0.0599)
628 (0.0003)
422 (0.3533)
548 (0.0058)
573 (0.0001)
406 (0.4415)
499 (0.6469)
570 (0.0967)
423 (0.2456)
574 (0.0022)
545 (0.0010)
430 (0.2889)
550 (0.0423)
573 (0.0015)
426 (0.3555)
527 (0.0022)
514 (0.0004)
420 (0.6851)
498 (0.8227)
533 (0.2377)
432 (0.1971)
551 (0.0024)
506 (0.0032)
433 (0.0009)
558 (0.0029)
560 (0.0002)
490 (0.0006)
516 (0.0007)
527 (0.0001)
500 (0.0003)
500 (0.0782)
599 (0.0123)
481 (0.0023)
503 (0.0005)
505 (0.0014)
49
50
51
a
b
Acidic ) 0.1 N HCl prepared by adding concd HCl; basic ) 0.1 N KOH prepared by adding 6 N KOH. ΦF Calculated using Coumarin
I in ethanol, quinine sulfate in 1.0 N H2SO4, or acridine yellow in methanol as standards.
dropyranyl ether 25 as a colorless oil (1.82 g, 98%). 1H NMR
(400 MHz, CDCl3) δ 1.54-2.03 (m, 6H), 3.15 (m, 2H), 3.34 (m,
2H), 3.62 (m, 1H), 3.91 (m, 1H), 5.42 (t, J ) 3.3 Hz, 1H), 6.81
(m, 1H), 6.89 (s, 1H), 6.96 (m, 1H), 7.22 (t, J ) 7.9 Hz, 1H);
MS (EI, 70 eV) m/ z (relative intensity) 332 (M+, off-scale), 248
(7), 121 (13), 85 (100), 77 (3), 67 (16), 57 (18), 43 (19). Anal.
Calcd for C13H17IO2: C, 47.01; H, 5.16; I, 38.20. Found: C,
47.10; H, 5.18; I, 38.02.
Gen er a l P r oced u r e for Alk yla t ion of Ket on es. To a
stirred suspension of sodium hydride (1.0-1.1 equiv of a 60%
w/w oil dispersion) in DMF at 0 °C was added dropwise a
solution of the ketone dissolved in DMF. After stirring at room
temperature for 4 h, a solution of 1.0-1.1 equiv of iodide 25
dissolved in DMF was then added dropwise. After stirring for
48 h, product isolation (saturated NH4Cl solution, EtOAc) and
purification afforded the alkylated ketones.
4′-[2-Ben zyloxy)eth oxy]-2-[3-(tetr a h yd r op yr a n -2-ylox-
y)p h en yl]-2-(2-p yr id yl)a cetop h en on e (26). Product isola-
tion and purification (1:1 EtOAc:hexane) afforded the mixture
of diastereomers 26 as a colorless oil (346 mg, 65% yield) from
ketone 17 (335 mg, 0.962 mmol), NaH dispersion (40 mg, 1.01
mmol), and iodide 25 (336 mg, 1.01 mmol) in 3 mL of DMF.
1H NMR (400 MHz, CDCl3) δ 1.56-2.05 (m, 6H), 2.22 (m, 1H),
2.52-2.67 (m, 3H), 3.54 (m, 1H), 3.81 (m, 2H), 3.89 (m, 1H),
4.16 (m, 2H), 4.61 (s, 2H), 4.85 (m, 1H), 5.36 (dt, J ) 14.9, 3.2
Hz, 1H), 6.70-6.77 (m, 3H), 6.88 (d, J ) 8.5 Hz, 2H), 7.10-
7.18 (m, 2H), 7.26-7.36 (m, 6H), 7.60 (m, 1H), 8.00 (m, 2H),
8.54 (m, 1H); MS (EI, 70 eV) m/ z (relative intensity) 551 (M+,
off-scale), 467 (2), 446 (2), 347 (23), 255 (28), 211 (4), 121 (8),
105 (5), 91 (100), 84 (29), 77 (5), 65 (8), 55 (34), 41 (20). Anal.
Calcd for C35H37NO5: C, 76.20; H, 6.76; N, 2.54. Found: C,
75.96; H, 6.78; N, 2.52.

1054 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
F igu r e 7. Resonance structures of the 2- and 4-pyridyl
dihydronaphthalenes and their related azaphenanthrenes.
3.08 mmol), and iodide 25 (1.02 g, 3.08 mmol) in 3 mL of DMF.
1H NMR (400 MHz, CDCl3) δ 1.56-2.01 (m, 6H), 2.13 (m, 1H),
2.48-2.59 (m, 3H), 3.55-3.61 (m, 1H), 3.82 (m, 2H), 3.89 (m,
1H), 4.16-4.19 (m, 2H), 4.48-4.53 (m, 1H), 4.62 (s, 2H), 5.34-
5.39 (m, 1H), 6.73-6.92 (m, 5H), 7.17-7.38 (m, 8H), 7.81-
7.86 (m, 2H), 8.00-8.54 (m, 2H); MS (EI, 70 eV) m/ z (relative
intensity) 551 (M+, off-scale), 467 (6), 347 (19), 255 (35), 121
(9), 106 (11), 91 (100), 84 (63), 77 (6), 69 (11), 55 (78), 43 (21).
Anal. Calcd for C35H37NO5: C, 76.20; H, 6.76; N, 2.54.
Found: C, 76.26; H, 6.69; N, 2.57.
Gen er a l P r oced u r e for Cycliza tion of Keton es. To a
solution of ketone in CH2Cl2 was added dropwise 5 equiv of
methanesulfonic acid. The olive green solution was allowed
to stir at room temperature for 24 h. Product isolation (H2O,
CH2Cl2) and purification yielded the cyclized phenol.
F igu r e 6. Fluorescence emission spectra of azaphenan-
threnoids 48-51. All spectra were obtained at the same
concentration (5 × 10-6 M) and under the same instrumental
conditions in EtOH (neutral) or EtOH with 0.1 N HCl (acidic)
or 0.1 N KOH (basic). Excitation was done at the maximum
absorbance of the longest wavelength ultraviolet absorption
peak under the same conditions (see Figure 5 or Table 4).
1-[4-[2-(Ben zyloxy)eth oxy]p h en yl]-6-h yd r oxy-2-(2-p y-
r id yl)-3,4-d ih yd r on a p h th a len e (29). The cyclized phenol
was obtained as a clear oil (1.86 g, 75%) from ketone 26 (3.06
g, 5.54 mmol) and methanesulfonic acid (2.66 g, 27.7 mmol)
in 90 mL of CH2Cl2, after product isolation and purification
(1:1 EtOAc:hexane). An analytically pure sample was obtained
as a white solid by recrystallization from EtOAc/hexane. Mp
4′-[2-(Ben zyloxy)eth oxy]-2-[3-(tetr a h yd r op yr a n -2-ylox-
y)p h en yl]-2-(3-p yr id yl)a cetop h en on e (27). Product isola-
tion and purification (1:19 acetone:CH2Cl2) afforded the mix-
ture of diastereomers 27 as a colorless oil (320 mg, 55% yield)
from ketone 20 (366 mg, 1.05 mmol), NaH dispersion (42 mg,
1.05 mmol), and iodide 25 (349 mg, 1.05 mmol) in 2 mL of
DMF. 1H NMR (400 MHz, CDCl3) δ 1.57-2.01 (m, 6H), 2.11-
2.16 (m, 1H), 2.49-2.59 (m, 3H), 3.56-3.61 (m, 1H), 3.82 (m,
2H), 3.84-3.92 (m, 1H), 4.17 (m, 2H), 4.52-4.56 (m, 1H), 4.62
(s, 2H), 5.37 (dt, J ) 11.7, 3.3 Hz, 1H), 6.74-6.94 (m, 3H),
6.89 (m, 2H), 7.17-7.25 (m, 2H), 7.26-7.38 (m, 6H), 7.65-
7.69 (m, 1H), 7.84-7.88 (m, 2H), 8.48 (m, 1H), 8.57 (m, 1H);
MS (EI, 70 eV) m/ z (relative intensity) 551 (M+, off-scale), 467
(1), 347 (4), 255 (27), 243 (20), 213 (6), 120 (38), 106 (20), 91
(100), 85 (95), 78 (20), 67 (19), 57 (21), 51 (9), 43 (23). Anal.
Calcd for C35H37NO5: C, 76.20; H, 6.76; N, 2.54. Found: C,
76.21; H, 6.80; N, 2.50.
1
146-148 °C; H NMR (400 MHz, CDCl3) δ 2.85 (m, 4H), 3.83
(m, 2H), 4.13 (m, 2H), 4.65 (s, 2H, 6.55 (dd, J ) 8.5, 2.7 Hz,
1H), 6.66 (d, J ) 8.5 Hz, 1H), 6.72 (d, J ) 8.1 Hz, 1H), 6.75
(m, 1H), 6.81 (d, J ) 8.7 Hz, 2H), 6.97 (m, 1H), 6.98 (d, J )
8.7 Hz, 2H), 7.28-7.39 (m, 6H), 8.53 (m, 1H); MS (FAB) m/ z
450 (M+ + 1), 279, 223, 205, 195. Anal. Calcd for C30H27NO3:
C, 80.15; H, 6.05; N, 3.12. Found: C, 80.17; H, 6.06; N, 3.12.
1-[4-[2-(Ben zyloxy)eth oxy]p h en yl]-6-h yd r oxy-2-(3-p y-
r id yl)-3,4-d ih yd r on a p h th a len e (30). The cyclized phenol
was obtained as a clear oil (555 mg, 70%) was prepared from
ketone 27 (972 mg, 1.76 mmol) and methanesulfonic acid (847
mg, 8.81 mmol) in 30 mL of CH2Cl2, after product isolation
and purification (1:4 acetone:CH2Cl2). An analytically pure
sample was obtained as a white solid by recrystallization from
EtOAc/hexane. Mp ) 175-177 °C; 1H NMR (400 MHz, CDCl3)
δ 2.69 (m, 2H, 2.93 (m, 2H), 3.83 (m, 2H), 4.12 (m, 2H), 4.64
4′-[2-(Ben zyloxy)eth oxy]-2-[3-(tetr a h yd r op yr a n -2-ylox-
y)p h en yl]-2-(4-p yr id yl)a cetop h en on e (28). Product isola-
tion and purification (1:19 acetone:CH2Cl2) afforded the mix-
ture of diastereomers 28 as a colorless oil (969 mg, 61% yield)
from ketone 21 (1.02 g, 2.93 mmol), NaH dispersion (123 mg,

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1055
(s, 2H), 6.58 (dd, J ) 8.5, 2.5 Hz, 1H), 6.67 (d, J ) 8.3 Hz,
1H), 6.74 (d, J ) 2.5 Hz, 1H), 6.79 (d, J ) 8.8 Hz, 2H), 6.91 (d,
J ) 8.8 Hz, 2H), 7.14 (m, 1H), 7.27-7.40 (m, 6H), 8.29 (m,
2H); MS (FAB) m/ z 450 (M+ + 1), 223, 195. HRMS calcd for
C20H28NO3 (M + 1)+ 450.2069, found 450.2075.
1-[4-(2-H yd r oxyet h oxy)p h en yl]-2-(2-p yr id yl)-6-[(t r i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (35).
The product was obtained as a white foam (38 mg, 80%) from
ether 32 (56 mg, 0.096 mmol), iodotrimethylsilane (173 mg,
0.867 mmol), and thiophenol (12 mg, 0.11 mmol) in 2 mL of
CH2Cl2, after product isolation and purification (1:49 MeOH:
CH2Cl2). 1H NMR (400 MHz, CDCl3) δ 2.97 (m, 4H), 3.98 (m,
2H), 4.08 (m 2H), 6.72 (d, J ) 8.1 Hz, 1H), 6.83 (d, J ) 8.8 Hz,
2H), 6.88 (d, J ) 8.5 Hz, 1H), 6.97 (dd, J ) 8.5, 2.7 Hz, 1H),
6.98 (m, 1H), 6.99 (d, J ) 8.8 Hz, 2H), 7.13 (d, J ) 2.7 Hz,
1H), 7.30 (m, 1H), 8.55 (m, 1H); MS (FAB) m/ z 492 (M+ + 1).
Anal. Calcd for C24H20F3NO5S: C, 58.65; H, 4.10; F, 11.60;
N, 2.85; S, 6.52. Found: C, 58.42; H, 4.32; F, 11.44; N, 2.73;
S, 6.36.
1-[4-(2-H yd r oxyet h oxy)p h en yl]-2-(3-p yr id yl)-6-[(t r i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (36).
The product was obtained as a white foam (37 mg, 84%) from
ether 33 (52 mg, 0.089 mmol), iodotrimethylsilane (180 mg,
0.89 mmol), and thiophenol (9.8 mg, 0.089 mmol) in 2 mL of
CH2Cl2, after product isolation and purification (1:19 MeOH:
CH2Cl2). 1H NMR (400 MHz, CDCl3) δ 2.85 (m, 2H), 3.05 (m,
2H), 3.97 (m, 2H), 4.06 (m, 2H), 6.81 (d, J ) 8.8 Hz, 1H), 6.85
(d, J ) 8.6 Hz, 1H), 6.94 (d, J ) 8.8 Hz, 2H), 6.96 (dd, J ) 8.6,
2.5 Hz, 2H), 7.09 (dd, J ) 7.9, 4.8 Hz, 1H), 7.13 (d, J ) 2.5 Hz,
1H), 7.33 (dt, J ) 7.9, 2.0 Hz, 1H), 8.35 (m, 2H); MS (FAB)
m/ z 492 (M+ + 1). Anal. Calcd for C24H20F3NO5S: C, 58.65;
H, 4.10; F, 11.60; N, 2.85; S, 6.52. Found: C, 58.91; H, 4.18;
F, 11.37; N, 2.82; S, 6.41.
1-[4-(2-H yd r oxyet h oxy)p h en yl]-2-(4-p yr id yl)-6-[(t r i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (37).
The product was obtained as a yellow foam (145 mg, 88%) from
ether 34 (194 mg, 0.332 mmol), iodotrimethylsilane (666 mg,
3.33 mmol), and thiophenol (40 mg, 0.37 mmol) in 8 mL of
CH2Cl2, after product isolation and purification (1:19 MeOH:
CH2Cl2). 1H NMR (400 MHz, CDCl3) δ 2.83 (m, 2H), 3.03 (m,
2H), 3.98 (m, 2H), 4.06 (m, 2H), 6.82 (d, J ) 8.5 Hz, 2H), 6.86
(d, J ) 8.8 Hz, 1H), 6.92 (m, 2H), 6.93 (d, J ) 8.5 Hz, 2H),
6.95 (m, 1H), 7.13 (d, J ) 2.5 Hz, 1H), 8.36 (m, 2H); MS (FAB)
m/ z 492 (M+ + 1), 359. Anal. Calcd for C24H20F3NO5S: C,
58.65; H, 4.10; F, 11.60; N, 2.85; S, 6.52. Found: C, 58.56; H,
4.13; F, 11.52; N, 2.81; S, 6.48.
1-[4-[2-(Ben zyloxy)eth oxy]p h en yl]-6-h yd r oxy-2-(4-p y-
r id yl)-3,4-d ih yd r on a p h th a len e (31). The cyclized phenol
was obtained as a clear oil (1.27 g, 78%) from ketone 28 (2.00
g, 3.64 mmol) and methanesulfonic acid (1.75 g, 18.2 mmol)
in 60 mL of CH2Cl2, after product isolation and purification
(1:4 acetone:CH2Cl2). An analytically pure sample was ob-
tained as a yellow solid by recrystallization from EtOAc/
1
hexane. Mp 168-170 °C; H NMR (400 MHz, CDCl3) δ 2.76
(m, 2H), 2.92 (m, 2H), 3.83 (m, 2H), 4.13 (m, 2H), 4.64 (s, 2H),
6.55 (dd, J ) 8.5 Hz, 2.5 Hz, 1H), 6.67 (d, J ) 8.5 Hz, 1H),
6.73 (d, J ) 2.5 Hz, 1H), 6.81 (d, J ) 8.8 Hz, 2H), 6.91 (d, J )
6.3 Hz, 2H), 6.93 (d, J ) 8.8 Hz, 2H), 7.26-7.41 (m, 5H), 8.29
(d, J ) 6.3 Hz, 2H); MS (FAB) m/ z 450 (M+ + 1), 279, 223,
169. Anal. Calcd for C30H27NO3: C, 80.15; H, 6.05; N, 3.12.
Found: C, 79.78; H, 6.09; N, 3.05.
Gen er a l P r oced u r e for Tr ifla tion of P h en ols. Trifluo-
romethanesulfonic anhydride (1.5 equiv) was added to a
solution of the phenol and 2,6-lutidine (2.0 equiv) in CH2Cl2
at 0 °C. After stirring for 1 h while warming to room
temperature, product isolation (H2O, CH2Cl2) and purification
afforded the aryl triflate.
1-[4-[2-(Ben zyloxy)eth oxy]p h en yl]-2-(2-p yr id yl)-6-[(tr i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (32).
The product was obtained as a colorless oil (56 mg, 87% yield)
from phenol 29 (50 mg, 0.11 mmol), triflic anhydride (48 mg,
0.17 mmol), and 2,6-lutidine (24 mg, 0.22 mmol) in 10 mL of
CH2Cl2, after product isolation and purification (1:2 EtOAc:
hexane). 1H NMR (400 MHz, CDCl3) δ 2.96 (m, 4H), 3.84 (m,
2H, 4.14 (m, 2H), 4.65 (s, 2H), 6.71 (d, J ) 8.1 Hz, 1H), 6.82
(d, J ) 8.3 Hz, 2H), 6.88 (d, J ) 8.6 Hz, 1H), 6.95 (dd, J ) 8.6,
2.7 Hz, 1H), 6.97 (d, J ) 8.3 Hz, 2H), 6.98 (m, 1H), 7.13 (d, J
) 2.7 Hz, 1H), 7.22-7.40 (m, 6H), 8.55 (m, 1H); MS (FAB)
m/ z 582 (M+ + 1). Anal. Calcd for C31H26F3NO5S: C, 64.02;
H, 4.51; F, 9.80; N, 2.41; S, 5.51. Found: C, 63.97; H, 4.50; F,
9.72; N, 2.40; S, 5.47.
1-[4-[2-(Ben zyloxy)eth oxy]p h en yl]-2-(3-p yr id yl)-6-[(tr i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (33).
The product was obtained as a colorless oil (78 mg, 79% yield)
from phenol 30 (76 mg, 0.17 mmol), triflic anhydride (72 mg,
0.25 mmol), and 2,6-lutidine (36 mg, 0.34 mmol) in 5 mL of
CH2Cl2, after product isolation and purification (1:1 EtOAc:
hexane). 1H NMR (400 MHz, CDCl3) δ 2.82 (m, 2H), 3.03 (m,
2H 3.83 (m, 2H), 4.12 (m, 2H), 4.64 (s, 2H), 6.81 (d, J ) 8.5
Hz, 2H), 6.84 (d, J ) 8.7 Hz, 1H), 6.92 (d, J ) 8.5 Hz, 2H),
6.95 (dd, J ) 8.7, 2.5 Hz, 1H), 7.12 (d, J ) 2.5 Hz, 1H), 7.28-
7.40 (m, 6H), 8.35 (m, 2H); MS (FAB) m/ z 582 (M+ + 1), 447,
279. Anal. Calcd for C31H26F3NO5S: C, 64.02; H, 4.51; F, 9.80;
N, 2.41; S, 5.51. Found: C, 64.14; H, 4.54; F, 9.80; N, 2.41; S,
5.40.
1-[4-[2-(Ben zyloxy)eth oxy]p h en yl]-2-(4-p yr id yl)-6-[(tr i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (34).
The product was obtained as a colorless oil (314 mg, 79% yield)
from phenol 31 (307 mg, 0.682 mmol), triflic anhydride (288
mg, 1.02 mmol), and 2,6-lutidine (146 mg, 1.36 mmol) in 50
mL of CH2Cl2, after product isolation and purification (1:1
EtOAc:hexane). 1H NMR (400 MHz, CDCl3) δ 2.81 (m, 2H,
3.02 (m, 2H), 3.84 (m, 2H), 4.13 (m, 2H), 4.65 (s, 2H), 6.82 (d,
J ) 8.6 Hz, 2H), 6.86 (d, J ) 8.5 Hz, 1H), 6.91 (d, J ) 8.6 Hz,
2H), 6.92 (m, 2H), 6.96 (dd, J ) 8.5, 2.5 Hz, 1H), 7.13 (d, J )
2.5 Hz, 1H), 7.28-7.40 (m, 5H), 8.36 (m, 2H); MS (FAB) m/ z
582 (M+ + 1), 449. Anal. Calcd for C31H26F3NO5S: C, 64.02;
H, 4.51; F, 9.80; N, 2.41; S, 5.51. Found: C, 63.97; H, 4.49; F,
9.75; N, 2.40; S, 5.52.
Gen er a l P r oced u r e for Mesyla tion of P r im a r y Alco-
h ols. Methanesulfonyl chloride (MsCl) (3 equiv) was added
to a solution containing the alcohol (1 equiv) and Et3N (3 equiv)
in THF at 0 °C. The reaction was allowed to warm to room
temperature as it stirred for 1 h, and product isolation (H2O,
EtOAc) and purification afforded the mesylate.
1-[4-[2-[(Meth a n esu lfon yl)oxy]eth oxy]p h en yl]-2-(2-p y-
r idyl)-6-[(tr iflu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph -
th a len e (38). The product was obtained as a white foam (321
mg, 89%) from alcohol 35 (312 mg, 0.635 mmol), MsCl (218
mg, 1.90 mmol), and Et3N (192 mg, 1.90 mmol) in 10 mL of
THF, after product isolation and purification (2:1 EtOAc:
hexane). 1H NMR (400 MHz, CDCl3) δ 2.98 (m, 4H), 3.11 (s,
3H), 4.24 (m, 2H), 4.58 (m, 2H), 6.72 (d, J ) 8.1 Hz, 1H), 6.81
(d, J ) 8.8 Hz, 2H), 6.86 (d, J ) 8.5 Hz, 1H), 6.95 (dd, J ) 8.5,
2.4 Hz, 1H), 7.01 (d, J ) 8.8 Hz, 2H), 7.02 (m, 1H), 7.14 (d, J
) 2.4 Hz, 1H), 7.31 (t, J ) 8.1 Hz, 1H), 8.55 (m, 1H); MS (FAB)
m/ z 570 (M+ + 1). Anal. Calcd for C25H22F3NO7S2: C, 52.72;
H, 3.89; F, 10.01; N, 2.46; S, 11.26. Found: C, 52.35; H, 4.05;
F, 9.83; N, 2.33; S, 11.15.
1-[4-[2-[(Meth a n esu lfon yl)oxy]eth oxy]p h en yl]-2-(3-p y-
r idyl)-6-[(tr iflu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph -
th a len e (39). The product, was obtained as a white foam (67
mg, 93%) from alcohol 36 (63 mg, 0.13 mmol), MsCl (44 mg,
0.38 mmol), and Et3N (39 mg, 0.38 mmol) in 10 mL of THF,
after product isolation and purification (1:19 MeOH:CH2Cl2).
1H NMR (400 MHz, CDCl3) δ 2.82 (m, 2H), 3.03 (m, 2H), 3.10
(s, 3H), 4.22 (m, 2H), 4.56 (m, 2H), 6.80 (d, J ) 8.1 Hz, 2H),
6.83 (d, J ) 8.8 Hz, 1H), 6.95 (d, J ) 8.1 Hz, 2H), 6.96 (m,
1H), 7.13 (d, J ) 2.4 Hz, 1H), 7.19 (dd, J ) 7.8, 4.9 Hz, 1H),
7.42 (d, J ) 7.8 Hz, 1H), 8.29 (s, 1H), 8.35 (d, J ) 4.9 Hz, 1H);
MS (FAB) m/ z 570 (M+ + 1). HRMS calcd for C25H23F3NO7S2
(M + 1) 570.0868, found 570.0860.
Gen er a l P r oced u r e for Clea va ge of Ben zyl E t h er s.
Iodotrimethylsilane (4.0-5.0 equiv) was added to a solution
of the benzyl ether (1.0 equiv) and thiophenol (1.0 equiv) in
CH2Cl2. An additional 4.0-5.0 equiv of iodotrimethylsilane
was added after 12 h of stirring at room temperature. After
stirring for another 12 h, product isolation (5% aqueous
Na2S2O3, CH2Cl2) and purification afforded the desired alcohol.
1-[4-[2-[(Meth a n esu lfon yl)oxy]eth oxy]p h en yl]-2-(4-p y-
r idyl)-6-[(tr iflu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph -

1056 J . Org. Chem., Vol. 62, No. 4, 1997
Scribner et al.
th a len e (40). The product was obtained as a yellow foam (240
mg, 95%) from alcohol 37 (217 mg, 0.442 mmol), MsCl (151
mg, 1.32 mmol), and Et3N (134 mg, 1.32 mmol) in 15 mL of
THF, after product isolation and purification (1:19 MeOH:CH2-
Cl2). 1H NMR (400 MHz, CDCl3) δ 2.82 (m, 2H), 3.03 (m, 2H),
3.11 (s, 3H), 4.24 (m, 2H), 4.58 (m, 2H), 6.81 (d, J ) 8.8 Hz,
2H), 6.85 (d, J ) 8.8 Hz, 1H), 6.95 (d, J ) 8.8 Hz, 2H), 6.97
(m, 3H), 7.14 (d, J ) 2.5 Hz, 1H), 8.38 (m, 2H); MS (FAB) m/ z
570 (M+ + 1). Anal. Calcd for C25H22F3NO7S2: C, 52.72; H,
3.89; F, 10.01; N, 2.46; S, 11.26. Found: C, 52.62; H, 3.94; F,
9.84; N, 2.41; S, 11.19.
Gen er a l P r oced u r e for Azir id in a tion of Meth a n e-
su lfon a tes.32 Ethylenimine34 (50 equiv) was added to a
solution of the methanesulfonate (1 equiv) in 1:1 CH3CN:Et3N
and stirred for 12 h at room temperature, after which an
additional 50 equiv of ethylenimine were added. After 24 h
total reaction time, the reaction mixture was concentrated
under a stream of nitrogen. The crude mixture was then
dissolved in the appropriate chromatography solvent (a small
amount of CH2Cl2 was added to dissolve if necessary) and then
loaded directly onto a silica column and flash chromato-
graphed.
1-[4-(2-Azir id in ylet h oxy)p h en yl]-2-(2-p yr id yl)-6-[(t r i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (41).
The product was obtained as a yellow oil (59 mg, 72%) from
mesylate 38 (90 mg, 0.16 mmol) and ethylenimine34 (677 mg,
1.57 mmol) in 1 mL of CH3CN:Et3N, after product isolation
and purification (1:19 Et3N:EtOAc). 1H NMR (400 MHz,
CDCl3) δ 1.24 (m, 2H), 1.80 (m, 2H), 2.61 (m, 2H), 2.93 (m,
4H), 4.11 (m, 2H), 6.72 (d, J ) 8.1 Hz, 1H), 6.83 (d, J ) 8.5
Hz, 2H), 6.88 (d, J ) 8.5 Hz, 1H), 6.94 (m, 1H), 6.96 (d, J )
8.5 Hz, 2H), 6.97 (m, 1H), 7.12 (d, J ) 2.4 Hz, 1H), 7.26 (m,
1H), 8.53 (m, 1H); MS (FAB) m/ z 517 (M+ + 1). Anal. Calcd
for C26H23F3N2O4S: C, 60.46; H, 4.49; F, 11.03; N, 5.42; S, 6.21.
Found: C, 60.48; H, 4.48; F, 10.93; N, 5.42; S, 6.20.
1-[4-(2-Azir id in ylet h oxy)p h en yl]-2-(3-p yr id yl)-6-[(t r i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (42).
The product was obtained as a yellow oil (25 mg, 73%) from
mesylate 39 (37 mg, 0.065 mmol) and ethylenimine34 (280 mg,
6.50 mmol) in 1 mL of CH3CN:Et3N, after product isolation
and purification (1:9 Et3N:EtOAc). 1H NMR (400 MHz, CDCl3)
δ 1.25 (m, 2H), 1.81 (m, 2H), 2.61 (m, 2H), 2.82 (m, 2H), 3.02
(m, 2H), 4.10 (m, 2H), 6.81 (d, J ) 8.5 Hz, 2H, 6.86 (d, J ) 8.8
Hz, 1H), 6.89 (m, 1H), 6.92 (d, J ) 8.5 Hz, 2H), 7.05 (m, 1H),
7.12 (d, J ) 2.5 Hz, 1H), 7.29 (m, 1H), 8.30 (m, 2H); MS (FAB)
m/ z 517 (M+ + 1). HRMS calcd for C26H24F3N2O4S (M + 1)+
517.1409, found 517.1411.
1-[4-(2-Azir id in ylet h oxy)p h en yl]-2-(4-p yr id yl)-6-[(t r i-
flu or om eth an esu lfon yl)oxy]-3,4-dih ydr on aph th alen e (43).
The product was obtained as a yellow oil (20 mg, 77%) from
mesylate 40 (28 mg, 0.049 mmol) and ethylenimine34 (212 mg,
4.80 mmol) in 1 mL of CH3CN:Et3N, after product isolation
and purification (1:9 Et3N:EtOAc). 1H NMR (400 MHz) δ 1.25
(m, 2H), 1.81 (m, 2H), 2.62 (m, 2H), 2.80 (m, 2H, 3.01 (m, 2H),
4.12 (m, 2H), 6.83 (d, J ) 8.8 Hz, 2H), 6.86 (d, J ) 8.8 Hz,
1H), 6.91 (d, J ) 8.8 Hz, 2H), 6.93 (m, 3H), 7.12 (d, J ) 2.5
Hz, 1H), 8.34 (m, 2H); MS (FAB) m/ z 517 (M+ + 1). Anal.
Calcd for C26H23F3N2O4S: C, 60.46; H, 4.49; F, 11.03; N, 5.42;
S, 6.21. Found: C, 60.54; H, 4.79; F, 10.91; N, 5.39; S, 6.14.
Gen er a l P r oced u r e for Dep r otection of P h en ols. To
a solution of the aryl triflate in THF was added LiAlH4 (5
equiv) at room temperature. An additional 5 equiv was added
after 1 h of stirring. After a total reaction time of 2 h, the
reaction mixture was poured into a flask containing diethyl
ether and 1:1 (v/v) Celite:Na2SO4‚10H2O. The mixture was
filtered, and the filtrate was dried over Na2SO4 and concen-
trated under reduced pressure to afford the crude phenol,
which was then purified by reverse phase HPLC (1:9 H2O:
MeOH).
as a yellow oil (11.3 mg, 84%), was prepared from aryl triflate
41 (18 mg, 0.035 mmol) and LiAlH4 (13.3 mg, 0.350 mmol) in
2 mL of THF. 1H NMR (400 MHz, CDCl3) δ 1.35 (m, 2H), 1.90
(m, 2H), 2.68 (m, 2H), 2.89 (m, 4H), 4.13 (m, 2H), 6.54 (d, J )
8.5 Hz, 1H), 6.66 (d, J ) 8.5 Hz, 1H), 6.71 (m, 1H), 6.79 (m,
1H), 6.80 (d, J ) 8.7 Hz, 2H), 6.96 (m, 1H), 6.97 (d, J ) 8.7
Hz, 2H), 7.27 (m, 1H), 8.52 (m, 1H); MS (FAB) m/ z 385 (M+
+ 1). HRMS calcd for C25H25N2O2 (M + 1) 385.1916, found
385.1920.
1-[4-(2-Azir id in ylet h oxy)p h en yl]-6-h yd r oxy-2-(3-p y-
r id yl)-3,4-d ih yd r on a p h th a len e (11). The product, isolated
as a yellow oil (6.5 mg, 83%), was prepared from aryl triflate
42 (10.5 mg, 0.020 mmol) and LiAlH4 (7.8 mg, 0.20 mmol) in
1 mL of THF. 1H NMR (400 MHz, CDCl3) δ 1.33 (m, 2H), 1.85
(m, 2H), 2.65 (m, 2H), 2.75 (m, 2H), 2.92 (m, 2H), 4.11 (m,
2H), 6.52 (dd, J ) 8.3, 2.5 Hz, 1H), 6.64 (d, J ) 8.3 Hz, 1H),
6.70 (m, 1H), 6.75 (d, J ) 8.7 Hz, 2H), 6.92 (d, J ) 8.7 Hz,
1H), 7.01 (dd, J ) 7.0, 4.8 Hz), 7.25 (m, 1H), 8.24 (m, 2H); MS
(FAB) m/ z 385 (M+ + 1). HRMS calcd for C25H25N2O2 (M +
1) 385.1916, found 385.1917.
1-[4-(2-Azir id in ylet h oxy)p h en yl]-6-h yd r oxy-2-(4-p y-
r id yl)-3,4-d ih yd r on a p h th a len e (12). The product, isolated
as a yellow oil (11.6 mg, 80%), was prepared from aryl triflate
43 (19.5 mg, 0.039 mmol) and LiAlH4 (14 mg, 0.38 mmol) in 2
mL of THF. 1H NMR (400 MHz) δ 1.25 (m, 2H), 1.80 (m, 2H),
2.61 (m, 2H), 2.81 (m, 2H), 2.96 (m, 2H), 4.11 (m, 2H), 6.55 (d,
J ) 8.5 Hz, 1H), 6.63 (d, J ) 8.5 Hz, 1H), 6.70 (m, 1H), 6.81
(d, J ) 8.7 Hz, 2H), 6.91 (d, J ) 8.7 Hz), 6.92 (m, 2H), 8.34
(m, 2H); MS (FAB) m/ z 385 (M+ + 1). HRMS calcd for
C25H25N2O2 (M + 1) 385.1916, found 385.1909.
Gen er a l P r oced u r e for P h otocycliza tion of Stilba zoles
to Aza p h en a n th r en es. A solution of the stilbazole in cyclo-
hexane (0.6 M) in a water cooled quartz vessel was irradiated
for 2 h by 16 bulbs emitting light at 300 nm inside a Rayonet
photoreactor (see General section). The reaction mixture was
then concentrated under reduced pressure and purified by
flash chromatography.
12-Aza -7-[2-(b e n zyloxy)e t h oxy]b e n zo[g]-2-[(t r iflu o-
r om eth a n esu lfon yl)oxy]-13,14-d ih yd r och r ysen e (44). The
product was isolated as a yellow oil (24 mg, 65%) from
stilbazole 32 (37 mg, 0.063 mmol) following flash chromatog-
raphy (1:1 EtOAc:hexane). 1H NMR (400 MHz, CDCl3) δ 2.97
(m, 2H), 3.49 (m, 2H), 3.96 (m, 2H, 4.40 (m, 2H), 4.70 (s, 2H),
7.25 (dd, J ) 8.5, 2.7 Hz, 1H), 7.29-7.43 (m, 7H), 7.53 (dd, J
) 8.4, 4.4 Hz, 1H), 7.88 (d, J ) 8.5 Hz, 1H), 8.09 (d, J ) 2.7
Hz, 1H), 8.38 (d, J ) 9.3 Hz, 1H), 8.84 (dd, J ) 8.4, 1.5 Hz,
1H), 8.98 (d, J ) 4.4, 1.5 Hz, 1H); MS (EI, 70 eV) m/ z (relative
intensity) 579 (M+, 100), 446 (84), 418 (61), 311 (8), 296 (5),
284 (15), 267 (7), 255 (25), 240 (4), 153 (6), 121 (5), 105 (7), 91
(87), 84 (4), 77 (6), 65 (6), 55 (4), 44 (18), 39 (4). Anal. Calcd
for C31H24F3NO5S: C, 64.21; H, 4.17; F, 9.83; N, 2.42; S, 5.53.
Found: C, 64.26; H, 4.18; F, 9.86; N, 2.45; S, 5.52.
11-Aza -7-[2-(b e n zyloxy)e t h oxy]b e n zo[g]-2-[(t r iflu o-
r om eth a n esu lfon yl)oxy]-13,14-d ih yd r och r ysen e (45). The
product was isolated as a yellow oil (11 mg, 32%) from
stilbazole 33 (35 mg, 0.059 mmol) following flash chromatog-
raphy (pure EtOAc after 1:1 EtOAc:hexane finished eluting
46). 1H NMR (400 MHz, CDCl3) δ 2.98 (m, 2H), 3.27 (m, 2H),
3.97 (m, 2H), 4.41 (m, 2H), 4.70 (s, 2H), 7.24 (dd, J ) 8.5, 2.4
Hz, 1H), 7.29-7.43 (m, 7H), 7.80 (d, J ) 8.5 Hz, 1H), 8.11 (d,
J ) 2.4 Hz, 1H), 8.30 (d, J ) 5.6 Hz, 1H), 8.36 (d, J ) 9.0 Hz,
1H), 8.73 (d, J ) 5.6 Hz, 1H), 9.52 (s, 1H). MS (EI, 70 eV)
m/ z (relative intensity) 579 (M+, 6), 446 (5), 312 (1), 295 (4),
283 (4), 266 (7), 254 (11), 240 (5), 226 (4), 213 (1), 105 (4), 91
(100), 79 (13), 77 (9), 55 (4). Anal. Calcd for C31H24F3NO5S:
C, 64.21; H, 4.17; F, 9.83; N, 2.42; S, 5.53. Found: C, 64.10;
H, 4.19; F, 9.80; N, 2.44; S, 5.49.
9-Aza -7-[2-(b e n zyloxy)e t h oxy]b e n zo[g]-2-[(t r iflu o-
r om eth a n esu lfon yl)oxy]-13,14-d ih yd r och r ysen e (46). The
product was isolated as a yellow oil (12 mg, 35%) from
stilbazole 33 (35 mg, 0.059 mmol) following flash chromatog-
raphy (1:1 EtOAc:hexane). 1H NMR (400 MHz, CDCl3) δ 2.98
(m, 2H), 3.17 (m, 2H), 3.97 (m, 2H), 4.49 (m, 2H), 4.70 (s, 2H),
7.25 (dd, J ) 8.5, 2.7 Hz, 1H), 7.27-7.43 (m, 7H), 7.57 (dd, J
) 8.4, 4.4 Hz, 1H), 7.89 (d, J ) 8.5 Hz, 1H), 8.32 (d, J ) 9.0
Hz, 1H), 8.44 (d, J ) 8.4, 1.5 Hz, 1H), 8.82 (d, J ) 2.7 Hz,
1-[4-(2-Azir id in ylet h oxy)p h en yl]-6-h yd r oxy-2-(2-p y-
r id yl)-3,4-d ih yd r on a p h th a len e (10). The product, isolated
(33) Simpson, D. M.; Elliston, J . F.; Katzenellenbogen, J . A. J .
Steroid Biochem. 1987, 28, 233.
(34) See cautionary note at the end of the General section at the
beginning of the Experimental Section.

Photofluorogenic Ligands for the Estrogen Receptor
J . Org. Chem., Vol. 62, No. 4, 1997 1057
1H), 8.97 (dd, J ) 4.4, 1.5 Hz, 1H); MS (EI, 70 eV) m/ z (relative
intensity) 579 (M+, off-scale), 446 (3), 312 (1), 284 (1), 256 (2),
236 (3), 213 (1), 198 (3), 177 (5), 167 (5), 156 (100), 112 (36),
91 (26), 77 (5), 55 (24). Anal. Calcd for C31H24F3NO5S: C,
64.21; H, 4.17; F, 9.83; N, 2.42; S, 5.53. Found: C, 64.24; H,
4.30; F, 9.76; N, 2.27; S, 5.49.
10-Aza -7-[2-(b e n zyloxy)e t h oxy]b e n zo[g]-2-[(t r iflu o-
r om eth a n esu lfon yl)oxy]-13,14-d ih yd r och r ysen e (47). The
product was isolated as a yellow oil (70 mg, 77%) from
stilbazole 34 (92 mg, 0.16 mmol) following flash chromatog-
raphy (2:1 EtOAc:hexane). 1H NMR (400 MHz, CDCl3) δ 2.99
(m, 2H), 3.15 (m, 2H), 3.97 (m, 2H), 4.42 (m, 2H), 4.71 (s, 2H),
7.26 (dd, J ) 8.6, 2.5 Hz, 1H), 7.28-7.43 (m, 7H), 7.84 (d, J )
8.6 Hz, 1H), 7.89 (d, J ) 5.7 Hz, 1H), 8.24 (d, J ) 2.5 Hz, 1H),
8.35 (d, J ) 9.0 Hz, 1H), 8.73 (d, J ) 5.7 Hz, 1H), 9.95 (s, 1H).
MS (EI, 70 eV) m/ z (relative intensity) 579 (M+, 25), 446 (14),
312 (5), 254 (4), 105 (4), 91 (100), 65 (4). HRMS calcd for
C31H24 F3NO5S 579.1327, found 579.1318.
10-Aza -7-[2-(b en zyloxy)et h oxy]b en zo[g]-2-h yd r oxy-
13,14-d ih yd r och r ysen e (50). The product, isolated as a
yellow oil (5.5 mg, 66%), was prepared from aryl triflate 47
(10.8 mg, 0.019 mmol) and LiAlH4 (7.1 mg, 0.19 mmol) in 2
mL of THF and flash chromatographed (2:1 EtOAc:hexane).
1H NMR (400 MHz, CDCl3) δ 2.93 (m, 2H), 3.12 (m, 2H, 3.97
(m, 2H), 4.42 (m, 2H), 4.70 (s, 2H), 6.83 (dd, J ) 8.5, 2.4 Hz,
1H), 6.92 (d, J ) 2.4 Hz, 1H), 7.22-7.44 (m, 6H), 7.65 (d, J )
8.7 Hz, 1H), 7.88 (d, J ) 4.9 Hz, 1H), 8.24 (d, J ) 2.2 Hz, 1H),
8.42 (d, J ) 8.5 Hz, 1H), 8.68 (d, J ) 4.9 Hz, 1H), 9.92 (s, 1H);
MS (EI, 70 eV) m/ z (relative intensity) 447 (M+, 4), 296 (3),
284 (4), 265 (1), 254 (2), 239 (1), 226 (2), 213 (1), 105 (4), 91
(100), 77 (10), 65 (11). HRMS calcd for C30H25NO3 447.1834,
found 447.1826.
9-Aza-7-[2-(ben zyloxy)eth oxy]ben zo[g]-2-h ydr oxy-13,14-
d ih yd r och r ysen e (51). The product, isolated as a yellow oil
(4 mg, 67%), was prepared from aryl triflate 46 (8.5 mg, 0.015
mmol) and LiAlH4 (5.6 mg, 0.15 mmol) in 2 mL of THF and
flash chromatographed (1:1 EtOAc:hexane). 1H NMR (400
MHz, CDCl3) δ 2.89 (m, 2H), 3.11 (m, 2H), 3.96 (m, 2H), 4.49
(m, 2H), 4.70 (s, 2H), 6.83 (dd, J ) 8.7, 2.7 Hz, 1H), 6.90 (d, J
) 2.7 Hz, 1H), 7.21-7.42 (m, 6H), 7.54 (dd, J ) 8.2, 4.0 Hz,
1H), 7.69 (d, J ) 8.5 Hz, 1H), 8.38 (d, J ) 8.7 Hz, 1H), 8.39
(m, 1H), 8.80 (d, J ) 2.9 Hz, 1H), 8.92 (dd, J ) 4.0, 1.5 Hz,
1H); MS (EI, 70 eV) m/ z (relative intensity) 447 (M+, 14), 326
(6), 312 (9), 296 (12), 284 (24), 266 (10), 254 (10), 240 (5), 226
(5), 213 (3), 189 (1), 105 (5), 91 (100), 77 (12), 65 (15). HRMS
calcd for C30H25NO3 447.1834, found 447.1817.
Gen er a l P r oced u r e for Dep r otection of P h en ols. The
same procedure was used here as for the deprotection of
aziridinyl phenols 10-12. The products were flash chromato-
graphed after workup.
12-Aza -7-[2-(b en zyloxy)et h oxy]b en zo[g]-2-h yd r oxy-
13,14-d ih yd r och r ysen e (48). The product, isolated as a
yellow oil (7 mg, 60%), was prepared from aryl triflate 44 (15
mg, 0.026 mmol) and LiAlH4 (9.9 mg, 0.26 mmol) in 2 mL of
THF and flash chromatographed (1:1 EtOAc:hexane). 1H
NMR (400 MHz, CDCl3) δ 2.89 (m, 2H), 3.44 (m, 2H, 3.96 (m,
2H), 4.40 (m, 2H), 4.70 (s, 2H), 6.83 (dd, J ) 8.3, 2.7 Hz, 1H),
6.92 (d, J ) 2.7 Hz, 1H), 7.27-7.42 (m, 6H), 7.50 (dd, J ) 8.3,
4.2 Hz, 1H), 7.69 (d, J ) 9.3 Hz, 1H), 8.08 (d, J ) 2.4 Hz, 1H),
8.45 (d, J ) 8.3 Hz, 1H), 8.85 (dd, J ) 8.3, 1.6 Hz, 1H), 8.96
(dd, J ) 4.2, 1.6 Hz, 1H); MS (EI, 70 eV) m/ z (relative
intensity) 447 (M+, 100), 312 (29), 295 (5), 283 (19), 254 (4),
91 (53), 73 (6), 57 (8), 43 (12). HRMS calcd for C30H25NO3
447.1834, found 447.1830.
11-Aza -7-[2-(b en zyloxy)et h oxy]b en zo[g]-2-h yd r oxy-
13,14-d ih yd r och r ysen e (49). The product, isolated as a
yellow oil (5.0 mg, 81%), was prepared from aryl triflate 45
(8.0 mg, 0.013 mmol) and LiAlH4 (4.9 mg, 0.13 mmol) in 2 mL
of THF and flash chromatographed (2:1 EtOAc:hexane). 1H
NMR (400 MHz, CDCl3) δ 2.89 (m, 2H), 3.23 (m, 2H, 3.96 (m,
2H), 4.40 (m, 2H), 4.69 (s, 2H), 6.86 (dd, J ) 8.2, 2.5 Hz, 1H),
6.93 (d, J ) 2.5 Hz, 1H), 7.32-7.39 (m, 6H), 7.61 (d, J ) 9.3
Hz, 1H), 8.11 (d, J ) 2.5 Hz, 1H), 8.32 (d, J ) 5.7 Hz, 1H),
8.45 (d, J ) 8.2 Hz, 1H), 8.68 (d, J ) 5.7 Hz, 1H), 9.51 (s, 1H);
MS (EI, 70 eV) m/ z (relative intensity) 447 (M+, 10), 312 (10),
296 (8), 284 (12), 266 (7), 254 (8), 239 (6), 226 (6), 213 (3), 200
(2), 115 (3), 105 (7), 91 (100), 77 (18), 65 (18). HRMS calcd for
C30H25NO3 447.1834, found 447.1830.
Biologica l P r oced u r es. Rela tive Bin d in g Affin ity for
th e Estr ogen Recep tor . Radiometric competitive binding
assays were performed as previously reported,27 using lamb
uterine cytosol diluted to approximately 1.5 nM of receptor,
which was incubated with buffer or several concentrations of
unlabeled competitor together with 10 nM [3H]estradiol for
18-24 h. Free ligand was removed by adsorption to dextran-
coated charcoal. Unlabeled competitors were prepared and
serially diluted in 1:1 DMF:buffer (10 mM Tris, 1.5 mM EDTA,
3 mM sodium azide, pH 7.4) to ensure solubility.
Estr ogen Recep tor In a ctiva tion . Time-dependent as-
says for the inactivation of the estrogen receptor were per-
formed as previously reported,28 using lamb uterine cytosol.
Ack n ow led gm en t. We are grateful for the support
of this research through a grant from the National
Institutes of Health (PHS 5R37 DK15556).
J O9618029