Antenna-initiated photochemistry in polyfunctional steroids. Intramolecular singlet and triplet energy transfer between aryl, ketone, and alkene groups in 6β-(Dimethylphenylsiloxy)-5β-androstanes 1

Article abstract of DOI:10.1021/jo952202x

Steroids have been prepared that bear a dimethylphenylsiloxy (DPSO) group and additional C3 and/or C17 ketone functionalities. The DPSO group has been used to harvest 266 nm photons and then activate the ketone functionalities through intramolecular singlet-singlet energy transfer (intra-SSET). Thus, the monoketones 3,3-(ethylenedioxy)-6β-(DPSO)-5β-androstan-17-one (6) and 6β-(DPSO)-5β-androstan-3-one (8) both exhibit DPSO-initiated photochemistry at the carbonyl groups. Irradiation of the diketone, 6β-(DPSO)-5β-androstane-3,17-dione (5), gives two ring D-derived photoproducta, an epimer (19) and an enal (18), both coming from the C17 ketone excited singlet state. Here Φ_intra-SSET from the aryl antenna to the carbonyl groups is ca. 88% efficients and occurs with a rate of ca. 6.5 × 10⁹ s^-1, with the chemistry indicative of facile intra-SSET between the C3 and C17 ketones. The alkylidene group at C3 (i.e., as in 6β-(DPSO)-3(E)-ethylidene-5β-androstan-17-one (33) and its Z isomer (34)) has no effect on the rate or efficiency of aryl activation of the C17 ketone.

Full text of DOI:10.1021/jo952202x

J . Org. Chem. 1996, 61, 7045-7055
7045
An ten n a -In itia ted P h otoch em istr y in P olyfu n ction a l Ster oid s.
In tr a m olecu la r Sin glet a n d Tr ip let En er gy Tr a n sfer betw een Ar yl,
Keton e, a n d Alk en e Gr ou p s in
6â-(Dim eth ylp h en ylsiloxy)-5â-a n d r osta n es1
S. Anna J iang, Changhe Xiao, and Harry Morrison*
Department of Chemistry, Brown Building, Purdue University, West Lafayette, Indiana 47907-1393
Received December 12, 1995X
Steroids have been prepared that bear a dimethylphenylsiloxy (DPSO) group and additional C3
and/or C17 ketone functionalities. The DPSO group has been used to harvest 266 nm photons and
then activate the ketone functionalities through intramolecular singlet-singlet energy transfer
(intra-SSET). Thus, the monoketones 3,3-(ethylenedioxy)-6â-(DPSO)-5â-androstan-17-one (6) and
6â-(DPSO)-5â-androstan-3-one (8) both exhibit DPSO-initiated photochemistry at the carbonyl
groups. Irradiation of the diketone, 6â-(DPSO)-5â-androstane-3,17-dione (5), gives two ring
D-derived photoproducts, an epimer (19) and an enal (18), both coming from the C17 ketone excited
singlet state. Here Φintra-SSET from the aryl antenna to the carbonyl groups is ca. 88% efficients
and occurs with a rate of ca. 6.5 × 109 s-1, with the chemistry indicative of facile intra-SSET between
the C3 and C17 ketones. The alkylidene group at C3 (i.e., as in 6â-(DPSO)-3(E)-ethylidene-5â-
androstan-17-one (33) and its Z isomer (34)) has no effect on the rate or efficiency of aryl activation
of the C17 ketone.
In tr od u ction
intramolecular singlet-singlet; intra-SSET) and triplet
(intramolecular triplet-triplet; intra-TTET) energy-trans-
fer processes. The alkene at C17 in 3 and 4 has served
a similar function in that it is exclusively activated by
intra-TTET. For example, in 1 and 3 there is efficient
intra-SSET from the DPSO group to C11, intersystem
crossing into the triplet manifold, and a transfer of triplet
energy to C17 via intra-TTET. The result is exemplified
by the chemistry shown in eq 1, where one may note the
There has been extensive recent interest in the in-
tramolecular transmission of electrons and excited state
energy in polyfunctional molecules. A number of these
efforts are directed toward the preparation of molecular
electronic and photonic wires.2 In our laboratory we have
been studying photochemistry resulting from intramo-
lecular electronic energy transfer among functionalities
in polyfunctional steroids.3 In this program we have
utilized an antenna group (e.g., a dimethylphenylsiloxy
(DPSO) functionality) to harvest photon energy and have
explored the efficiency and selectivity by which this
energy can be redistributed so as to activate distal
functionalities. In particular, we have been employing
multiple arrangements of antenna and acceptor groups
in order to understand the consequences of intramolecu-
lar energy migration by both through-bond and through-
space interactions (TBI and TSI, respectively). The
distances between, and relative orientations of, the donor
(DPSO) and the acceptor (typically, ketone or olefin)
groups, as well as the positional relationships of the
acceptor chromophores, have been varied in order to
elucidate the dependence of internal energy migration
on these factors.
Structures 1-4 depict functionality relationships we
have reported on to date.3 They are classified according
to the spatial relationships of donor (D) and acceptor
groups (A) (Chart 1). The “terminal” C17 carbonyl group
in 1 and 2 has proven diagnostically useful because its
singlet and triplet chemistry are easily differentiable and
the ketone itself does not undergo significant intersystem
crossing.3 This has allowed us to use this ketone as a
“reporter” group to distinguish between singlet (i.e.,
difference in chemistry observed when 1 is excited into
the antenna (266 nm) or the ketone groups (308 nm) in
the presence of reductant, triethylamine (TEA).3c The
localization of triplet energy at C17, which results in the
reduction of the ring D ketone, is likewise manifested as
Z/E isomerization of the C17 alkene in 3 and 4.3a,b In
all three cases the C11 and C6 ketones may be thought
X Abstract published in Advance ACS Abstracts, September 1, 1996.
(1) Organic Photochemistry. 112. Part 111: Post, A. J .; Morrison,
H. J . Org. Chem. 1996, 61, 1560-1561. Presented, in part, at the 209th
National Meeting of the American Chemical Society, 1995, Anaheim,
CA. Abstracted from the Doctoral Dissertation of S. A. J iang, Purdue
University, Aug 1995.
(3) (a) Agyin, J . F; Morrison, H. J . Am. Chem. Soc., in press. (b)
Morrison, H.; Agyin, K.; J iang A.; Xiao, C. Pure Appl. Chem. 1995, 67,
111-116. (c) Wu, Z.-Z.; Nash, J .; Morrison, H. J . Am. Chem. Soc. 1992,
114, 6640-6648. (d) Wu, Z.-Z.; Morrison, H. J . Am. Chem. Soc. 1992,
114, 4119-4128. (e) Wu, Z.-Z.; Morrison, H. Photochem. Photobiol.
1989, 50, 525-530.
(2) Wagner, R. A.; Lindsey, J . S. J . Am. Chem. Soc. 1994, 116, 9759-
9760 and references therein.
S0022-3263(95)02202-X CCC: $12.00 © 1996 American Chemical Society

7046 J . Org. Chem., Vol. 61, No. 20, 1996
J iang et al.
Ch a r t 1
of as functioning as “singlet-triplet switches” within the
steroid photonic wire. Though it appears that the C11
ketone is only able to transfer triplet energy to C17, the
C6 ketone can transfer singlet energy to C17 when an
appropriate (i.e., carbonyl) acceptor is present.3d
Treatment with acetone and a catalytic amount of
PdCl2(CH3CN)2 for 2-3 days9 effected cleavage of the
diketal to give a 4:1 mixture of 16 and the derivatized
monoketone 17 in ca. 60% yield. Silylation of these
products with chlorodimethylphenylsilane (DPSCl) gave
5 and 6 in 80% yield.3 NMR analysis of 5 using 2D
NOESY showed two crosspeaks corresponding to the
correlation of both the 19-CH3 at δ 1.2 and the 18-CH3
at δ 0.85 with the DPSO methyl groups at δ 0.35 and
0.39. This confirmed the axial orientation of the DPSO
group in the assignment of 5 as a 5â-androstane. Com-
pound 8 was prepared by first removing the 17-CdO
group in 9 using NH2NH2 in diethylene glycol and then
proceeding as in Scheme 1.
In the present study we describe the results of three
structural modifications in the steroid “wire” that are of
mechanistic interest (cf. 5, 33, 34): we have employed
ring A/B cis-fused 5â-androstanes as the molecular
scaffold, we have inserted the DPSO antenna at C6
between the potential 3 and 17 ketone acceptor groups
(the latter thus being at the maximum separation allowed
by the steroid framework; cf. 5), and we have inserted a
triplet “gate” at C3 that could be expected to efficiently
intercept C6 DPSO triplets (33, 34). We expect the
concept of multiplicity “gates” to prove quite useful in
developing the properties of such photonic wires.
We also report on several monoketonic models that
help us to elucidate the energy migration pathways in
these trifunctional substrates.
Resu lts
Syn th esis of Com p ou n d s 5, 6, 8, 33 a n d 34. 6â-
(DPSO)-5â-androstane-3,17-dione (5) was prepared in
five steps as shown in Scheme 1. Compound 10 was
prepared in ca. 55% yield by oxidation of the alcohol 9
and purified by chromatography. After protection of the
carbonyl groups to give a mixture of 12, 13, and 14 (8:
2:1), hydroboration and oxidation of 12 afforded 3,3;17,-
17-bis(ethylenedioxy)-6â-hydroxy-5â-androstane (15) as
the major isomer. The stereochemical assignment for 15
6â-(DPSO)-3(E)-ethylidene-5â-androstan-17-one (33)
and its Z-isomer (34) were prepared by a modification of
Scheme 1; i.e., the diketo alcohol, 16, was treated with
ethyltriphenylphosphonium bromide to give a mixture of
E and Z isomers (32) in a ratio of 1.6:1. Dimethylphen-
ylsilylation of this gave a mixture of 33 and 34 that was
purified by flash and Chromatotron chromatography and
then separated by HPLC. The assignment of the major
isomer as having the E configuration was established
1
was based on the characteristic H NMR chemical shift
and splitting pattern for HC-6â-OH at 3,74-3.72 δ.4,5 The
addition from the â face is consistent with reports that
hydrogenation of the 5/6 double bond in steroids bearing
substituents at C3 preferentially affords 5â-products.6-8
1
from 1-D H and 2-D COSY, NOESY, and HMQC NMR
spectroscopy. For this isomer, the H-2 protons at δ 1.68-
1.61 and the H-4 proton at 1.01-0.92 are coupled to the
(4) Bridgeman, J . E.; Cherry, P. C.; Clegg, A. S.; Evans, J . M.; J ones,
E. R. H.; Kumar, V.; Meakins, G. D.; Morisawa, Y.; Richards, E. E.;
Woodgate, P. D. J . Chem. Soc. C 1970, 250-257.
(7) Shoppee, C. W.; Pierce, J . H.; Stephenson, R. J .; Summers, G.
H. R. J . Chem. Soc. 1955, 694-703.
(8) Schmitt, J .; Panhouse, J . J .; Hallot, A.; Cornu, P.; Pluchet, H.
Bull. Soc. Chim. Fr. 1963, 807.
(5) Pouchert, C. J .; Behuke, J . The Aldrich Library of 13C and 1H
FT NMR Spectra; Aldrich: Milwaukee, 1993.
(9) Lipshutz, B. H.; Pollart, D.; Monforte, J .; Kotsuki, H. Tetrahedron
Lett. 1985, 26, 705-708.
(6) Lewis, J . R.; Shoppee, C. W. J . Chem. Soc. 1955, 1365-1370.

Antenna-Initiated Photochemistry in Steroids
J . Org. Chem., Vol. 61, No. 20, 1996 7047
Sch em e 1
methyl group on the olefin at δ 1.59-1.58 but not to the
vinyl proton. This is consistent with placement of C2 as
cis to the methyl group and trans to the vinyl proton.
Support is provided by the existence of a very clear
crosspeak for an H-4 resonance at δ 1.75-1.68 with the
vinyl proton resonance at δ 5.33-5.28. Thus, we con-
clude that the major isomer (33) has the E configura-
tion.10
P h otoch em istr y. P h otolysis of 5 in MeCN a t 266
n m . Irradiation of 5 (11.4 mM) in MeCN with 266 nm
laser light (6 mJ /pulse) for 7 min resulted in the forma-
tion of two primary photoproducts generated from R
cleavage in ring D: the enal, 6â-(DPSO)-3-oxo-13,17-seco-
5â-androst-13-en-17-al (18) and the epimer of 5, 6â-
(DPSO)-5â,13R-androstane-3,17-dione (19). Also de-
tected was a mixture of the alcohols, 6â-(DPSO)-3â-
hydroxy-5â-androstan-17-one (20) and its 3R isomer (21),
which are generated by reduction of the 3-carbonyl group
in 5. These products were formed in a ratio of 18:19:(20
+ 21) ) 1:2.5:0.2 (eq 2).
The structural assignments for these products are
1
based on their H and 13C NMR and mass spectral data.
Both 18 and 19 are isomeric with 5. Compound 18 has
characteristic 17-CHdO and allylic 18-CH3 singlet reso-
nances at δ 9.70 and 1.65, respectively, in good agreement
with literature data and our previous observations.3c,d,11
The 13C NMR spectrum shows resonances at δ 202 and
212 corresponding to the 17-CHdO and a CdO in a six-
membered cyclic ketone (the resonance at δ 221 corre-
sponding to the 17-CdO in 5 is absent).5,12 For 19 the
C/D cis ring fusion is supported by the characteristic
upfield shift of the 19-CH3 group to δ 1.04 from 1.24 in
5, as observed3c,d for the epimeric photoproducts of 1 and
2 (e.g., the resonances for the 19-CH3 group in 1 and its
epimer appear at δ 0.99 and 0.81, respectively; the upfield
(11) Iriarte, V. J .; Schaffner, K.; J eger, O. Helv. Chim. Acta 1964,
47, 1255-1264.
(10) Interestingly, a second, downfield H-4 resonance is also coupled
with the vinyl methyl resonance.
(12) Kalinowski, H.-O.; Berger, S.; Braun, S. 13C-NMR Spektrosko-
pie; George Thieme Verlag: Stuttgart, 1984; pp 173, 245.

7048 J . Org. Chem., Vol. 61, No. 20, 1996
J iang et al.
Ta ble 1. Tim e Cou r se a n d P r od u ct Ra tios for th e
P h otolysis of 5 w ith TEA
time (min)
18
19
20 + 21
10
20
30
40
1
1
1
1
3.0
3.3
3.2
3.3
0.4
0.6
0.8
0.8
carried out with varying concentrations of TEA confirm
the fact that C17 chemistry proceeds independent of C3
reduction (see Table 1).
P h otolysis of 5 in MeCN a t 308 n m . An acetonitrile
solution of 5 (10.56 mM) was irradiated with 308 nm
laser light for 5 min and found to form compounds 18,
19, and (20 + 21) in a ratio of 1:2.3:0.3 (cf. eq 2).
Photolysis for a shorter irradiation time gave only 18 and
19 (1:2.8) with 20 and 21 undetectable. Photolysis with
TEA (ca. 50 mM) gave 18, 19, 20, and 21 in a ratio of
1:3.8:0.5 with a shorter photolysis again yielding only 18
and 19 (1:3.5).
P h otolysis of th e C17 Mon ok eton e (6) in MeCN
a t 266 a n d 308 n m . An acetonitrile solution of 6 (9.0
mM) was irradiated at 266 nm (3.8 mJ /pulse) for 1.33
min. Two primary photoproducts involving R cleavage
at C17 were formed: the enal (22) and the epimer (23)
(1:2.8) (eq 3). 1H and 13C NMR spectra were obtained
shift is due to the placement of the 19-CH3 group within
the shielding cone of the 17-keto group when there is a
cis C/D ring fusion). There is a slight (i.e., δ 0.09 )
downfield shift of the 18-CH3 resonance, which is also
consistent with our previous results and attributable to
a change of this methyl from an axial configuration in 5
to an equatorial configuration in the epimer.13 The
retention of both the 3- and the 17-keto groups is
evidenced by their 13C NMR resonances at δ 212 and 222,
respectively.
The two isomeric alcohols, 20 and 21, formed in a ratio
of 1:2.5, could not be separated and their structure
assignments are based on IR and NMR spectral data
obtained on the mixture. The OH function is evident in
the IR spectrum by a sharp peak at ca. 3650 cm-1. That
reduction has occurred at the C3 position is evidenced
by the 13C NMR spectrum in which the resonances for
the 3-C-â-OH and 3-C-R-OH are found at δ 71.3 and 73.3,
respectively, a good fit to the data for authentic com-
pounds containing a 3-C-OH group; i.e., the correspond-
ing resonances in (+)-dihydrocholesterol and (+)-dehy-
droandrosterone occur at δ 71.3 and 71.4, respectively.5
The resonance for a 17-C-OH normally occurs further
downfieldstypically δ 80-85.5 As expected, one observes
the characteristic resonance for the 17-C cyclopentanone
at 222.4 δ. Finally, the 1H NMR chemical shifts and
splitting patterns at 3.54 and 4.02 δ match that expected
for HC-3R-OH and HC-3â-OH, respectively, with the 3R-
OH as the major isomer.4
for samples isolated from a preparative photolysis. The
structure for 22 is supported by the 17-CHdO and allylic
18-CH3 resonances at δ 9.67-9.69 and 1.61(s), respec-
tively. There is also a characteristic 17-CHdO resonance
at δ 201.8 in the 13C NMR spectrum. Compound 23 was
identified by the upfield shift of the 19-CH3 resonance to
δ 0.96 (from δ 1.17 in 6), and a corresponding downfield
shift of the 18-CH3 resonance from δ 0.85 to 0.94. The
continued presence of the five-membered ring 17-CdO
is evidenced by the 13C NMR resonance at δ 222.4. The
photolysis of 6 with 308 nm light gave the same two
products in a similar ratio.
P h otolysis of 5 in MeCN w ith TEA a t 266 n m .
Irradiation of 5 (10.25 mM) in MeCN with TEA (28.7
mM) using 266 nm laser light (5 mJ /pulse) again gave
the enal 18, the epimer 19, and the alcohols 20 and 21.
The products were formed in a ratio of 1:3.5:0.3.
A
photolysis of 5 (14.80 mM; TEA 89.4 mM) was monitored
as a function of time and gave the ratios of products
shown in Table 1. The relative insensitivity of the
chemistry at C17 to the presence of TEA (and consequent
C3 chemistry) is noteworthy; quantum efficiency studies
P h otolysis of th e C3 Mon ok eton e, 8, a t 266 a n d
308 n m . Photolysis of 8 (10.6 mM) in MeCN with 266
nm laser light (3.6 mJ /pulse) for 14.5 min gave two
products (26 and 27 in a ratio of 1:2.4) that were
subsequently isolated as a mixture by a preparative
(13) Silverstein, R. M.; Bassler, G. C.; Morrill, T. C. Spectrometric
Identification of Organic Compounds; J ohn Wiley & Sons: New York,
1991; p 175.
1
photolysis. A H NMR spectrum indicated that these

Antenna-Initiated Photochemistry in Steroids
J . Org. Chem., Vol. 61, No. 20, 1996 7049
were enals since resonances appeared at δ 9.92, 9.43 and
5.67-5.03 (eq 4). The same enals were formed upon
photolysis of 8 in MeCN with 308 nm laser light, but in
slightly higher yield than with 266 nm irradiation.
Photolysis of 8 with TEA (53.0 mM) using 266 nm light
gave two isomeric alcohols in a ratio of 1:1.5. Their
structures were assigned as compounds 28 and 29 on the
1
basis of resonances in the H NMR at δ 3.4-3.5 for the
HC-3R-OH (29) and δ 3.9-4.2 for the HC-3â-OH (28).
This was also the case when 8 was photolyzed in MeCN
containing TEA using 308 nm light.14
P h otolysis of 33 a n d 34 in MeCN a t 266 n m .
Irradiation of 33 (8.48 mM) or 34 (7.58 mM) in MeCN
with 266-nm laser light (4 mJ /pulse) for 1 min resulted
in the formation of three primary photoproducts in both
cases. Compound 33 gave its Z isomer and the ring D
cleavage products, enal 35 and epimer 36 (see eq 5).
Photolysis of 34 also gave three primary photoproducts,
the E isomer, and the ring D cleavage products 37 and
38 (eq 6).
The ring D cleavage products were obtained by a
preparative photolysis of a mixture of 33 and 34 (27.2
mM) in MeCN with 266-nm laser light. The three pairs
of isomers were detected by GLC analysis. The struc-
tural assignments for compounds 35-38 follow from the
1H and 13C NMR spectra of the mixture. The presence
of the two isomeric enals was indicated by a pair of
characteristic 17-CHdO resonances at δ 9.75-9.73 and
9.71-9.68 and allylic 18-CH3 singlets at ca. δ 1.62, in
good agreement with literature data and our previous
observations.3c,d,11 The 13C NMR spectrum shows the
absence of the resonance at δ 221 corresponding to the
17-CdO in 33 and 34 and a new resonance at δ 202
corresponding to the 17-CHdO carbon.5,12
been observed previously3c,d and is due to the placement
of the 19-CH3 group within the shielding cone of the 17-
keto group when there is a cis C/D ring fusion. There is
a smaller downfield shift of the 18-CH3 resonance from
δ 0.65 to 0.93 which is also consistent with our previous
results and attributable to a change of this methyl from
an axial configuration in 1 and 2 to an equatorial
configuration in the epimer.12 Finally, the retention of
the 17-keto group is indicated by a 13C NMR resonance
at δ 222.
Resonances for the CHdC and allylic CH3 appear at δ
5.04-5.15 and 1.55-1.53, respectively. The olefinic
carbons are also evidenced by several signals at δ 114.68,
114.75, 114.77, and 139.21, 139.27, 139.30 in the 13C
NMR spectrum.
The C/D cis ring fusion in 36 and 38 is evidenced by
the characteristic upfield shift of the 19-CH3 resonances
to δ 0.96 from δ 1.24 in 33 and 34. The upfield shift has
(14) Analogous results were obtained by irradiation of the analogous
monoketone, 6â-(dimethylphenylsiloxy)-5â-cholestan-3-one (7), in cy-
clohexane with 266 nm and 308 nm laser light. The â (24) and R (25)
alcohols were isolated in a ratio of 1:4.5. Details may be found in ref
15.
(15) J iang, S. A. Doctoral Dissertation, Purdue University, W.
Lafayette, IN, Aug 1995.
P h otolysis of 33 a n d 34 in MeCN a t 308 n m .
Acetonitrile solutions of 33 (8.48 mM) or 34 (7.58 mM)
were irradiated with 308-nm laser light (4 mJ /pulse) for
1 min and each found to form the same three photoprod-

7050 J . Org. Chem., Vol. 61, No. 20, 1996
J iang et al.
Ta ble 2. Qu a n tu m Efficien cies for P h otolysis of 5 w ith
266 a n d 308 n m Ligh t
solvent
% loss
Φ-5
Φ18
Φ19
266 nm
MeCN
C6H12
18
25
18.1 × 10-2
3.20 × 10-2
5.33 × 10-2
10.6 × 10-2
12.8 × 10-2
26.7 × 10-2
308 nm
MeCN
C6H12
10
18
30.8 × 10-2
6.85 × 10-2
7.35 × 10-2
20.6 × 10-2
20.8 × 10-2
31.9 × 10-2
Ta ble 3. Qu a n tu m Efficien cies for th e P h otolysis of 6 in
MeCN w ith 266 a n d 308 n m Ligh t
Φ-6
Φ22
Φ23
266 nm
21.2 × 10-2
26.3 × 10-2
4.25 × 10-2
9.58 × 10-2
16.0 × 10-2
308 nm
5.71 × 10-2
Ta ble 4. Qu a n tu m Efficien cies for P h otolysis of 5 in
MeCN in th e P r esen ce of [TEA] Usin g 266 a n d 308 n m
Ligh t
TEA (mM)
Φ-5
Φ18
Φ19
F igu r e 1. Absorption spectrum of compound 5 in acetonitrile.
Φ 266
28.7
11.7 × 10-2
10.1 × 10-2
13.3 × 10-2
11.1 × 10-2
11.4 × 10-2
2.13 × 10-2
2.02 × 10-2
2.23 × 10-2
1.70 × 10-2
1.81 × 10-2
6.28 × 10-2
5.64 × 10-2
7.13 × 10-2
6.39 × 10-2
6.17 × 10-2
Ta ble 6. Qu a n tu m Efficien cies for P h otolysis of 33 a n d
34 in MeCN
43.0
57.4
71.7
100.4
Compound 33
Φ-33
0.36
0.82
ΦEfZ
0.012
0.035
Φ35
0.13
0.26
Φ36
0.22
0.46
266 nm
308 nm
Φ 308
54.7
29.7 × 10-2
6.63 × 10-2
17.1 × 10-2
Ta ble 5. Qu a n tu m Efficien cies for P h otolysis of 8 in
CH3CN
Compound 34
ΦZfE
% loss
Φ-8
Φ26
Φ27
Φ-34
0.32
0.51
Φ37
0.064
0.10
Φ38
0.18
0.30
266 nm
12
9
7.78 × 10-2
10.4 × 10-2
1.06 × 10-2
4.36 × 10-2
6.60 × 10-2
266 nm
0.015
0.046
308 nm
1.81 × 10-2
308 nm
ucts as had been observed with 266-nm irradiation. The
ratios of these products were similar for 33 at the two
photolysis wavelengths but significantly different for the
irradiation of 34 (see eqs 5 and 6).
upon photolysis of 6, either at 266 or 308 nm. However,
the photoproducts from the photolysis of 8 with either
266 or 308 nm, both in the presence and absence of TEA,
were completely eliminated by 152 mM pentadiene.
Effect of Ad d ed Cyclop en ta n on e a n d Cycloh ex-
a n on e on th e P h otoch em istr y of 5. Cyclopentanone
and cyclohexanone were used to test for possible inter-
molecular energy transfer in 5.3d,e The addition of either
ketone in equimolar concentrations with 5 (ca. 11 mM)
had no effect on the 266 nm photolysis; i.e., there was
no change in the quantum efficiencies of product forma-
tion from 5 nor was there any loss of the added cycloal-
kanone.
Spectr oscopy. Absor ption Spectr a. The aryl DPSO
and the carbonyl chromophores typically show uv absorp-
tion maxima at ca. 260 nm and ca. 290 nm, respectively.18
The absorption spectrum of 5 is a composite of these
components, i.e., λ nm (ꢀ M-1 cm-1) 252 (194); 258 (257);
263 (273); 269 (203), 290 (53); cf. Figure 1. The absorp-
tion spectra of 33 and 34 are likewise composites of the
individual chromophores.
Qu a n tu m Efficien cies for P h otolysis of 5, 6, 8, 33,
a n d 34. Quantum efficiencies for the loss of the dione 5
(Φ-5), and the formation of 18 and 19 (Φ18 and Φ19), were
measured in MeCN and in cyclohexane with 266 and 308
nm laser light. The data are presented in Table 2 (no
reduction at C3 was observed). Quantum efficiencies for
the photolysis of 6 are shown in Table 3, and quantum
efficiencies for the photolysis of 5 as a function of TEA
concentration are shown in Table 4. Quantum efficien-
cies for the photolysis of 8, 33, and 34 at both 266 and
308 nm are given in Tables 5 and 6.
Qu en ch in g Stu d ies w ith cis-1,3-P en ta d ien e. cis-
1,3-Pentadiene (cis-piperylene) (ET ) 58.3 kcal/mol) is an
effective quencher of ketone triplets16 and has been used
to probe the excited state origin of photochemistry
occurring at C17.3 No quenching of product formation
was observed when compound 5 was irradiated in the
presence of 60-500 mM pentadiene using either 266 or
308 nm light.17 Similarly, no quenching was observed
F lu or escen ce Sp ectr a . The fluorescence spectra for
5, 6, 8, 33, and 34 elicited by 254 nm excitation all exhibit
(16) Turro, N. J . Modern Molecular Photochemistry; University
Science Books: Mill Valley, CA, 1991; pp 252, 436.
(17) In fact, some reaction enhancement was observed in the
presence of piperylene. This is due to the low conversion conditions
under which the quenching studies were run. We have observed that
secondary photochemistry destroys the photoproducts.
(18) Gilbert, A.; Baggott, J . Essentials of Molecular Photochemistry;
CRC Press: Boca Raton, FL, 1991; pp 182, 287.
(19) Birks, J . B. Photophysics of Aromatic Molecules; J ohn Wiley &
Sons Ltd.: New York, 1970; p 126.

Antenna-Initiated Photochemistry in Steroids
J . Org. Chem., Vol. 61, No. 20, 1996 7051
direct excitation of the carbonyl groups in 5 with 308 nm
light gave results virtually identical to that observed with
antenna excitation. There is good mass balance between
the loss of starting material and the formation of identi-
fied C17 products, as evidenced by a comparison of
quantum efficiencies (see Table 2), although the data are
somewhat better at 308 nm (ca. 90%) than at 266 nm
(68-76%). Comparable results were obtained with com-
pounds 6 and 8 (Tables 3 and 5). Interestingly, photoly-
sis at 308 nm gives quantum efficiency data for 5 that
are essentially identical in acetonitrile and cyclohexane,
whereas a somewhat less efficient reaction is observed
in the more polar solvent when the antenna is irradiated
at 266 nm (Table 2). We have noted in previous studies
that aryldecalones exhibit a diminished efficiency of aryl
to ketone intra-SSET in polar media.21 This was at-
tributed to the well-known blue-shift of the carbonyl n
f π* transition in polar solvents and the consequent
reduction in the emission/absorption spectral overlap
integral intrinsic to energy transfer. This point is
discussed further below.
Experiments with added ketones, TEA, and pentadiene
provide some useful mechanistic insights. Photolysis of
5 with 266 nm light in the presence of equimolar amounts
of either cyclopentanone or cyclohexanone gives no
evidence of quenching by the “external” ketones nor any
indication of photoproducts from these reagents. This
confirms that sensitization by the DPSO group is strictly
intramolecular, as has been observed in previous studies.3
Photolysis of 5 with TEA using 266 nm light increases
the amount of photochemistry at C3 (i.e., reduction to
20 and 21) without affecting either the relative amount
of the two C17 products (Table 1) or the quantum
efficiencies of their formation (Table 4). Both observa-
tions are consistent with C17 chemistry originating from
a singlet excited state. This conclusion is reinforced by
the lack of quenching of C17 chemistry in 5 by pentadi-
ene. Chemistry at C17 is typically singlet derived, unless
it is induced through specific triplet energy transfer3d
and, not surprisingly, the C17 chemistry displayed by 6
(eq 3) is also unquenchable. By contrast, the C3 chem-
istry induced in 8 (eq 5) is completely quenchable by
pentadiene and entirely triplet-derived.
F igu r e 2. Normalized fluorescence spectra for compounds 5,
6, and 8 upon excitation at 254 nm in acetonitrile.
Ta ble 7. F lu or escen ce Da ta for 5, 6, 8, 33, a n d 34 in
Aceton itr ile
λex
steroids
254 nm
254 nm
300 nm
Φf(aryl)a
Φf(ketone)b
Φf(ketone)c
5
6
8
33
34
30
31
6.0 × 10-4
9.5 × 10-4
1.1 × 10-3
1.1 × 10-3
1.3 × 10-3
5.3 × 10-3
3.6 × 10-3
4.1 × 10-3
8.4 × 10-4
4.3 × 10-3
4.2 × 10-3
2.7 × 10-3
3.1 × 10-3
7.2 × 10-4
4.0 × 10-3
3.7 × 10-3
1.2 × 10-3
Using toluene in cyclohexane as a reference (Φ ) 0.14).19
a
b
Using anthracene in cyclohexane as a reference (Φf ) 0.36).19
c Using acetone in cyclohexane as a reference (Φf ) 9.3 × 10-4).20
Ta ble 8. Sin glet Lifetim e Da ta for Com p ou n d s 5, 6, 8, 33,
34, a n d 30a
steroids
τf (aryl) ns
τf (ketone) ns
5
6
8
33
34
30
0.24 ( 0.01
0.22 ( 0.01
0.27 ( 0.04
0.28 ( 0.02
0.38 ( 0.01
1.29 ( 0.08
2.27 ( 0.01; 4.50 ( 0.01
4.92 ( 0.18
2.44 ( 0.24
4.6 ( 0.1
5.1 ( 0.1
a
All solutions in MeCN; excitation at 254 nm (aryl) and 300
nm (ketone).
dual emission, with the aryl and ketone fluorescence
centered at ca. 285 nm and 410 nm, respectively (Figure
2). Fluorescence quantum efficiencies were determined
by using toluene, anthracene, and acetone as reference
compounds. The data are given in Table 7, together with
data for compounds 303c and 31 as DPSO and ketone
standards. Fluorescence lifetimes for these substrates
were measured, and these data are summarized in Table
8.
Sp ectr oscop y a n d DP SO/Keton e In tr a -SSET. The
254 nm induced fluorescence spectra of three DPSO-
containing steroidal ketones, 5, 6, and 8, show dual
emission (cf. Figure 2). The quantum efficiencies for aryl
emission, and the aryl singlet lifetimes (cf. Tables 7 and
8), for these compounds are appreciably reduced relative
to the nonketonic model 30. The efficiencies of carbonyl
emission elicited by DPSO excitation are comparable to
those obtained by direct excitation with 300 nm light and
to that of the model steroidal ketone 31. These results
confirm that there is extensive intra-SSET between the
Discu ssion
P h otoch em istr y. Consistent with our observations
with analogous steroids such as 1 and 2 excitation of the
aryl antenna in 5 at 266 nm initiates carbonyl photo-
chemistry (cf. eq 1). Interestingly, the photochemistry
(R-cleavage to 18 and 19) primarily occurs at the C17
position rather than at the more proximal C3. However,
(20) Halpern, A. M.; Ware, W. R. J . Chem. Phys. 1971, 54, 1271.
(21) Morrison, H.; Pallmer, M.; Loeschen, R.; Pandey, B.; Muth-
uramu, K.; Maxwell, B. J . Org. Chem. 1986, 51, 4676-4681.

7052 J . Org. Chem., Vol. 61, No. 20, 1996
J iang et al.
Ta ble 9. Efficien cies a n d Ra tes for In tr a -SSET
pentanone bearing a disubstituted R carbon. The fact
that quenching of the C3 triplet by TEA has no effect on
C17 chemistry implies that the C3 and C17 triplets do
not communicate (a conclusion supported by the studies
with 33 and 34; see below).
steroid
Φintra-SSET
kintra-SSET (109 s-1
)
5
6
8
33
34
0.89a (0.81)b
0.82a (0.83)b
0.79a (0.79)b
0.79a (0.78)b
0.75a (0.71)b
3.2a (3.4)b
3.7a (3.8)b
2.9a (2.9)b
2.8a (2.8)b
2.0a (1.8)b
DP SO/Olefin a n d Keton e/Olefin Com m u n ica tion .
The existence of triplet ketone chemistry at C3, upon
antenna excitation in 8, could derive either from intra-
SSET and intersystem crossing of the C3 ketone singlet
or by intra-TTET from the DPSO group to C3. This
ambiguity is removed in 33 and 34 where only intra-
TTET to C3 is possible. In fact, excitation of the aryl
antenna initiates olefin isomerization of both the E and
the Z isomers, confirmation of intra-TTET, and the
potential of the alkene to function as a “triplet gate”. The
combination of the trapping of triplet energy by the C3
alkene gate, and the inefficient intersystem crossing of
the DPSO antenna caused by its rapid intra-SSET to the
C17 carbonyl group (Table 9), causes the primary chem-
istry in 33 and 34 to be the singlet-derived formation of
the enal and epimer C17 R-cleavage products. The lack
of DPSO intersystem crossing results in E/Z isomeriza-
tion in 33 and 34, upon 266 nm excitation, as only 3.3%
and 5.7% of the product, respectively, under the condi-
tions applied in the reactions listed in Table 6. As with
5, one can compare the ratios of the quantum efficiencies
for C17 singlet photochemistry when directly excited (308
nm) and indirectly excited (266 nm) (Table 6) to the
Φintra-SSET values in Table 9. For reasons we cannot
explain, the data do not match as well as for the
diketone: 60 vs 75%, respectively, for 34 and 50 v. 79%
for 33. Nevertheless, our observations with these tri-
functional steroids are generally consistent with the
mechanisms we have outlined for the DPSO/diketone
substrate, 5.23
Calculated from Φf data. Calculated from 1τ data.
a
b
DPSO and carbonyl groups, the efficiencies and rates for
which can be calculated using either the DPSO fluores-
cence quantum efficiency or lifetime data.3c,d The results
are given in Table 9. Note the generally good agreement
between the Φf and τf derived values.
The interchromophoric distances between the 6-DPSO
group and C3 or C17 in these steroids are 7.7 and 8.6 Å,
respectively.22 The magnitudes of both the efficiencies
and the rate constants of intra-SSET match well with
our earlier observations3c with DPSO containing steroidal
ketones in which the antenna and the carbonyl groups
are separated by ca. 7-9 Å (i.e., in earlier work, efficien-
cies and rates of energy transfer of 70-90% and 1-3 ×
109 s-1, respectively). Since the earlier data were drawn
from the 5R-androstane series, these results indicate that
the A/B ring fusion is not, in itself, critical to energy
migration within the steroid “wire”.
The extensive intra-SSET is also reflected in the
relative quantum efficiencies for photochemistry with 266
vs 308 nm excitation (Tables 2, 3, and 5). For compounds
6 and 8 the 266 nm/308 nm quantum efficiency ratios
are 74 and 75%, respectively, in excellent agreement with
the Φintra-SSET values in Table 9. Likewise, for 5 in
cyclohexane there is a very good match of the quantum
efficiency ratio (84%) and the Φintra-SSET data (though the
latter are from photophysical data in acetonitrile). An
anomaly is the match of the 266/308 nm ratio for 5 in
acetonitrile (58%) vs the DPSO/ketone intra-SSET ef-
ficiency. We have noted above that, in particular, the
quantum efficiency for 266 nm initiated chemistry in 5
is reduced in the polar medium. This could be caused
by a reduction in the DPSO to ketone energy transfer
efficiency in acetonitrile or some effect of the polar solvent
on the C3/C17 communication discussed below.
Con clu sion s. In summary, we have demonstrated
that a DPSO antenna at C6 in the 5â androstane series
can efficiently transfer singlet energy to a target group
at C17 and elicit chemistry at that site. Rates and
efficiencies match well with data from previously studied
5R androstanes. Energy transfer to C17 occurs in the
presence of either singlet or triplet energy acceptors at
C3. In fact, there is evidence that a C3 ketone can itself
efficiently transfer singlet energy to C17.
Our earlier work3 has implicated through-bond ex-
change energy transfer as a likely source of the DPSO
to ketone activation; the data presented herein are
consistent with this interpretation.
Exp er im en ta l Section
Complete details for the experimental portion of this paper
may be found in ref 15; the salient features are summarized
below.
Keton e/Keton e Com m u n ica tion . There are several
intriguing aspects of a comparison of compounds 5 and
its des C3 ketone analog, 6. Most striking are the
comparable quantum efficiencies for C17 product forma-
tion in the two compounds (cf. Tables 2 and 3). This is
despite the fact that there is little difference in the
magnitude or rate of intra-SSET from the C6 DPSO to
C3 (in 6) and to C17 (in 8) (Table 9). Assuming,
therefore, that energy transfer from the C6 DPSO group
to C3 and C17 is competitive in 5, there must be facile
communication between the C3 and C17 excited singlet
states. We attribute the fact that the singlet carbonyl
chemistry is focused entirely at C17 to the relatively large
rate constant anticipated for C-C cleavage in a cyclo-
In str u m en ta tion . 1H and 13C NMR spectra were obtained
using 200, 300, and 500 MHz NMR spectrometers. Infrared
spectra were recorded on a Perkin-Elmer Model 1800 FT-IR
spectrometer. Low-resolution mass spectra were obtained
using a gas chromatograph EI/CI mass spectrometer. High-
resolution mass spectra were recorded on a Kratos Model MS-
50; data from this instrument have a standard deviation of
1.98 parts per million. Ultraviolet absorption spectra were
recorded on a Perkin-Elmer Model Lambda 3B spectropho-
tometer. Steady state fluorescence spectra were recorded on
an SLM Aminco SPF-500C spectrofluorometer with a 250 W
xenon arc lamp. Quantum efficiencies were measured by
(23) We find it striking that direct excitation of the C17 carbonyl
group with 308 nm light in 33 and 34 also leads to isomerization of
the C3 alkene (4.6 and 10% of the product for 33 and 34, respectively;
Table 6). Though these results imply intra-TTET from the C17 ketone
triplet to C3, such an explanation would be inconsistent with the lack
of ISC we have observed in a C17 ketone. Studies of substrates lacking
the C6 DPSO group are in progress.
(22) Distance data were obtained by calculations using a Silicon
Graphics Personal Iris 4D/35 Computer with MacroModel V3.5X
Software: Mohamadi, F.; Richards, N. G. J .; Guida, W. C.; Liskamp,
R.; Lipton, M.; Caufield, C.; Chang, G.; Hendrickson, T.; Still, W. C.
J . Comput. Chem. 1990, 11, 440. MM2* method: Allinger, N. L. J .
Am. Chem. Soc. 1977, 99, 8127.

Antenna-Initiated Photochemistry in Steroids
J . Org. Chem., Vol. 61, No. 20, 1996 7053
reference to toluene and anthracene or acetone. Fluorescence
lifetimes were determined with an ISS K2-002 Digital MPF
computer-selectable cross-correlation lifetime spectrometer
with a xenon arc lamp as a light source and a WG280 cutoff
filter used in the emission light path when the emission
monochrometer was not used. Fluorescence lifetimes were also
obtained with a PTI Model LS 100 fluorescence lifetime
spectrometer using a nitrogen dye laser as the light source.
All the fluorescence studies were conducted in regular 10 ×
10 mm fluorescence cells and at room temperature with the
solutions purged with argon for at least 15 min prior to use.
Gas chromatography utilized a Varian 3700 FID capillary
instrument coupled to a Hewlett-Packard 3390A integrator,
with the following J & W Scientific DB-1, 0.25 µm film
thickness columns: (A) 15.0 m × 0.25 mm i.d., (B) 12.5 m ×
0.25 mm i.d., (C) 10.0 m × 0.25 mm i.d. The internal standard
for 6â-(DPSO)-5â-androstane-3,17-dione and 3,3-(ethylene-
dioxy)-6â-(DPSO)-5â-androstan-17-one (5 and 6) was 3R-
(DPSO)-5R-androstane-3,17-dione with response factors (RF)
from [mass (X)/mass (I.S.)] ) (RF) [area (X)/area (I.S.)] ) 0.86
and 0.90, respectively. The internal standard for 6â-(DPSO)-
5â-androstan-3-one (8) was 3R-(DPSO)-5R-androstan-17-one;
Rf ) 0.84. HPLC analyses and separations were conducted
on a Varian Star 9000 system equipped with a variable
wavelength UV-vis detector. The HPLC traces were recorded
with a HP3395 integrator. The HPLC columns used were an
Econosil C-18 column (Alltech) 25 cm × 4.6 mm, 10 µm, or a
Microsorb-MV C-18 column (Rainin) 25 cm × 4.6 mm, 5 µm.
Preparative separations were also carried out with a Chro-
matotron Model 7924T thin layer instrument (Harrison Re-
search). Melting points were determined with a Fisher-J ohns
apparatus and are uncorrected.
Ma ter ia ls. The following chemicals were obtained from the
Aldrich Chemical Co.; they were used as received and stored
at room temperature except where mentioned: 3â-hydroxy-
5-androsten-17-one ((+)-dehydroisoandrosterone); Celite; pyr-
idinium chlorochromate (PCC); 1,2-ethanediol; chlorodimeth-
ylphenylsilane (DPSCl), stored in a desiccator; cis-1,3-pen-
tadiene, stored at -20 °C; borane, 1.00 M solution in tetrahy-
drofuran (THF), stored at -20 °C; 5-cholesten-3â-ol (choles-
terol); di(ethylene glycol); hydrazine hydrate; ethyltriphe-
nylphosphonium bromide; potassium tert-butoxide, stored in
a desiccator; anthracene (99.9%); cyclopentanone; cyclohex-
anone; Florisil; benzene-d6 (99+% D); acetone (99.9+%); pal-
ladium(II) chloride. Flash column chromatography employed
E. Merck 9285, 230-400 mesh silica gel.
The following chemicals were obtained from other suppliers.
Fisher Chemical: hydrogen peroxide, 30 wt % solution in
water; Cambridge Isotope Laboratory: chloroform-d (99.8% D).
Mallinckrodt: tetrahydrofuran and diethyl ether, both distilled
under nitrogen from sodium-benzophenone ketyl in a recy-
cling still; triethylamine was distilled from calcium hydride
prior to use; N,N-dimethylformamide was treated with 4-Å
molecular sieves followed by distillation under reduced pres-
sure.
Spectrograde solvents: acetonitrile (Fisher; Baxter); hexane
(Fisher); cyclohexane (Fisher; Aldrich); toluene (Fisher); and
acetone (Fisher) were used in the photochemical and spectro-
scopic studies without further purification and kept stored
under dry nitrogen.
P h otolyses. Laser photolyses at 266 nm utilized a Con-
tinuum NY-61 Nd:YAG laser equipped with quadropole fre-
quency doubler. A 2× beam enlarger was used in front of the
photolysis cell to avoid cell damage. Laser photolyses at 308
nm utilized a Luminics EX-700 Pulsemaster Excimer laser
equipped with a Pyrex beam splitter. A 7 × 9 mm beam mask
was used in the photolyses of small solution volumes. Power
meters were Opher Model 3A-P-CAL-S or 30A-P. Sample
solutions were placed in 10 × 10 mm vycor square cells and
were purged with argon for at least 15 min prior to use. For
quantum efficiency determinations argon-degassed solutions
ca. 8-12 mM in substrate were irradiated with either 266- or
308-nm laser light for 1 min using the power meters for the
actinometry. The photolysates were analyzed by GC using
internal standards and appropriate response curves. All
photochemical studies were run at room temperature.
Syn th eses. 6â-(DP SO)-5â-a n d r osta n e-3,17-d ion e (5).
3â-Hydroxy-5-androstene-3,17-dione (10) was prepared by the
following sequence. 5-Androsten-3â-ol-17-one (2.27 g, 7.88
mmol) was dissolved in CH2Cl2 (40 mL) and added to a
suspension of PCC (6.80 g, 31.5 mmol) and Celite (4.76 g) in
CH2Cl2 (30 mL).24 The mixture was stirred for 3.5 h at rt.
The mixture was diluted with ether and filtered through a
short column of silica gel or Florisil, which were twice washed
with CH2Cl2 and ethyl acetate. Evaporation of the combined
organic solution gave a 4:1 mixture of 10 and its ∆3 isomer,
11, which was purified by flash column chromatography (35%
EtOAc/hexane) to give 10 as a white solid (1.20 g, 53%). IR
(Nujol): 1720 (3-CdO), 1740 (17-CdO) cm-1 1H NMR (CDCl3,
.
200 MHz) δ: 5.41-5.38 (d, 1 H), 3.28-2.81 (AB q, 2 H), 2.56-
1.26 (m, 17 H), 1.23 (s, 3 H), 0.93 (s, 3 H). 13C NMR (CDCl3,
200 MHz) δ: 221.10, 210.13, 138.82, 122.08, 51.34, 49.03,
48.01, 47.30, 37.24, 36.76, 36.49, 35.53, 31.21, 31.06, 30.36,
21.53, 20.30, 18.86, 13.23.
A mixture of 10 (1.20 g, 4.20 mmol), 2 equiv 1,2-ethanediol,
and 10 mg of p-toluenesulfonic acid monohydrate in toluene
was heated at reflux overnight, using a Dean-Stark head to
remove water as formed.25 The cooled reaction mixture was
diluted with an equal volume of ether and washed with 10%
sodium carbonate and then with water until neutral to litmus.
The washed organic layer was dried with anhydrous MgSO4
and evaporated to dryness under reduced pressure. The
residue was separated by flash column chromatography (35%
EtOAc/hexane) to give 3,3;17,17-bis(ethylenedioxy)-5-andros-
tene (12), 13, and 14 (8:2:1). Compounds 13 and 14 were
recycled to generate 12. Spectral data for 12. IR (CH2Cl2):
no absorption at 1720 (3-CdO) or 1740 (17-CdO) cm-1
.
1H
NMR (CDCl3, 200 MHz) δ: 5.36-5.34 (m, 1 H), 3.98-3.84 (m,
8 H), 2.54-2.09 (AB q, 2 H), 2.04-1.05 (m, 17 H), 1.03 (s, 3
H), 0.86 (s, 3 H). 13C NMR (CDCl3, 200 MHz) δ: 140.00,
121.81, 119.36, 109.30, 65.08, 64.49, 64.38, 64.14, 50.40, 49.36,
45.63, 41.66, 36.58, 36.15, 34.08, 32.09, 30.98, 30.89, 30.42,
22.63, 20.47, 18.67, 13.98.
A solution of 6.0 mL (6.0 mmol) of 1.00 M borane-THF
complex was added dropwise to a solution of 12 (1.50 g, 4.0
mmol) in 30 mL of dry THF in an ice bath. The reaction
mixture was stirred 1 h at 0 °C and then overnight at rt.
Excess borane was decomposed by dropwise addition of water
until hydrogen was no longer evolved. A 3 N solution of NaOH
(10 mL) was then added, followed by dropwise addition of 30%
H2O2 (10 mL). The mixture was stirred at 40-50 °C for 1 h
and then brought to rt. The aqueous phase was saturated with
NaCl and extracted with 3 × 25 mL of ether. The combined
organic layers were washed with water, dried over MgSO4, and
removed at reduced pressure. The residue was purified by
flash column chromatography (10% i-PrOH/hexane) to give a
mixture of 3,3;17,17-bis(ethylenedioxy)-6â-hydroxy-5R-andros-
tane, 15, and its 5R,6R-isomer (4:1) (2.0 g, 5.1 mmol, 85%). 1H
NMR (CDCl3, 200 MHz) δ: 3.95-3.84 , 3.78-3.72, 2.06-1.15,
1.14, 0.86. 13C NMR (CDCl3, 200 MHz) δ: 119.45, 109.33,
72.39, 65.08, 64.39, 64.10, 64.04, 50.19, 47.67, 45.92, 35.83,
34.57, 34.24, 34.02, 33.44, 30.71, 30.58, 29.54, 22.43, 20.08,
14.24.
Five mol % of PdCl2(CH3CN)2 was added to a solution of
2.0 g (5.1 mmol) of the mixture of 15 and its 5R,6R-isomer
dissolved in 40 mL of acetone.9 After the mixture was stirred
for 2 days at rt the acetone was removed under reduced
pressure and the resulting residue redissolved in ether. The
ether was washed with 3 × 25 mL of saturated NH4Cl and
water and dried over MgSO4. The solvent was removed at
reduced pressure and the residue purified by flash column
chromatography (25% i-PrOH/hexane) to give 6â-hydroxy-5â-
androstane-3,17-dione, 16 (0.50 g), and 6R-hydroxy-5R-andros-
tane-3,17-dione 17 (0.12 g). 16: 1H NMR (CDCl3, 200 MHz)
δ: 3.79-3.78 (d, 1 H), 2.52-1.31 (m, 20 H), 1.26 (s, 3 H), 0.93
(s, 3 H). 13C NMR (CDCl3, 200 MHz) δ: 221.22, 211.95, 71.24,
(24) Kurth, M. J .; O’Brien, M. J .; Hope, H.; Yanuck, M. J . Org. Chem.
1985, 50, 2626-2632. Parish, E. J .; Luo, C.; Parish, S.; Heidepriem,
R. W. Synth. Commun. 1992, 22(19), 2839-2847.
(25) Smith, S. W.; Newman, M. S. J . Am. Chem. Soc. 1968, 90,
1249-1253.

7054 J . Org. Chem., Vol. 61, No. 20, 1996
J iang et al.
51.25, 50.03, 47.83, 42.00, 41.88, 37.26, 36.40, 35.83, 34.80,
32.93, 31.57, 30.18, 24.53, 21.75, 20.24, 13.62. IR (CH2Cl2)
cm-1: 1712 (3-CdO), 1736 (17-CdO), 3200-3700 (O-H). MS
EI m/e: 304 (M+), 286 (M - H2O). MS CI m/e: 305 (M + H).
17: 1H NMR (CDCl3, 200 MHz) δ: 3.96-3.94 (s, 4 H), 3.76-
3.72 (d, 1 H), 2.42-1.26 (m, 20 H), 1.19 (s, 3 H), 0.86 (s, 3 H).
13C NMR (CDCl3, 200 MHz) δ: 221.35, 109.11, 73.07, 64.10,
64.03.
DPSCl in DMF-TEA gave 8, which was purified by several
passes through the Chromototron to afford a white solid. 1H
NMR (CDCl3, 200 MHz) δ: 7.69-7.39 (m, 5 H), 3.70-3.69 (m,
1H), 2.52-1.31 (m, 20 H), 0.96 (s, 3 H), 0.70 (s, 3 H), 0.36 (s,
3 H), 0.33 (s, 3 H). 13C NMR (CDCl3, 200 MHz) δ: 211.83,
139.75, 132.95, 129.20, 127.66, 71.98, 54.00, 53.40, 52.61,
41.75, 40.72, 40.22, 39.96, 38.50, 37.80, 36.47, 34.50, 25.32,
21.24, 20.40, 17.44, 12.70, -0.92, -1.33. MS (EI) m/e: calcd
425.2876, found 425.2863.
6â-(DP SO)-3(E)-et h ylid en e-5â-a n d r ost a n -17-on e a n d
Its Z Isom er (33 a n d 34). To a slurry of 2.9 g (7.8 mmol) of
ethyltriphenylphosphonium bromide, 20 mL of dry THF, and
1.3 g (11.6 mmol) of t-BuOK under an atmosphere of nitrogen
was added 2.1 g (6.8 mmol) of 16 in 10 mL of dry THF. The
mixture was stirred overnight at rt. The mixture was diluted
with ether and filtered through a short column of silica gel,
Compound 16 (0.50 g, 1.64 mmol) was silylated with DPSCl
(406 µL, 2.46 mmol) in dry DMF (3-5 mL) with anhydrous
TEA (0.3 mL) at 0 °C. The reaction mixture became cloudy
white immediately and then formed a light yellow precipitate.
The mixture was diluted with toluene (20 mL) and washed
successively with 2 × 3 mL of cold 5% NaHCO3, 2 × 3 mL of
cold HCl (5%), and once again with 2 × 3 mL of cold 5%
NaHCO3. The organic layer was dried over MgSO4 and
evaporated to give crude 5, which was purified twice by the
Chromatotron (20% EtOAc/hexane). Recrystallization from
hexane afforded white prisms (237 mg), mp 101-103 °C. GC
washed with 500 mL of Et2
O, and dried over MgSO4. After
evaporation of the solvent the residue was purified by silica
gel chromatography (35% EtOAc/hexane eluent) to give a
mixture of the E and Z isomers. The starting material, 16,
was recycled.
analysis (column A; 250 °C) showed 100.00% purity with tR
)
12.31 min. HPLC analysis using 100% CH3CN also indicated
100% purity (tR ) 5.12 min). 1H NMR (CDCl3, 200 MHz) δ:
7.60-7.35 (m, 5 H), 3.70-3.66 (m,1H), 2.48-1.28 (m, 20 H),
1.24 (s, 3 H, 19-Me), 0.90 (s, 3 H, 18-Me), 0.39 (s, 3 H), 0.35 (s,
3 H). 1H NMR NOESY (CDCl3, 500 MHz) showed correlations
for both the 19-Me and the 18-Me groups with the DPSO
methyl groups. 13C NMR (CDCl3, 200 MHz) δ: 221.24, 212.03,
138.38, 133.47, 129.79, 128.02, 71.86, 51.05, 49.83, 47.74,
41.82, 41.77, 37.25, 36.35, 35.67, 34.87, 33.22, 31.47, 30.06,
24.42, 21.42, 20.06, 13.67, -1.22, -2.01. MS EI m/e 438 (M+),
423 (M - Me), 361 (M - C6H5). MS CI m/e: 439 (M + H), 361
(M - C6H6). Anal. Calcd for C27H38O3Si: C, 73.93; H, 8.73
found: C,73.67; H, 8.98. High resolution MS EI m/e: calcd
438.2590, found 438.2577.
The mixture of E and Z isomers (425 mg, 1.35 mmol) was
silylated with DPSCl (330 µL, 2.46 mmol) in dry DMF (3-5
mL) with anhyd TEA (0.5 mL) for 1 h at 0 °C. The mixture
was diluted with toluene (20 mL) and washed successively with
2 × 3 mL of cold 5% NaHCO3, 2 × 3 mL of cold HCl (5%), and
once again with 2 × 3 mL of cold 5% NaHCO3. The organic
layer was dried over MgSO4 and evaporated to give a residue
of crude 33 and 34, which was purified twice by the Chroma-
totron (6% EtOAc/hexane) to afford a white solid (490 mg).
GLC analysis (10.0 m column; 240 °C) indicated a ratio of E:Z
of 1.6:1 (tR ) 6.2 and 5.9 min, respectively). HPLC analysis
(100% CH3CN) gave two overlapping peaks. A small amount
of 33 was separated from 34 by HPLC using an analytical C-18
column with 100% CH3CN as eluent. Spectral data for the
mixture of 75% 33 and 25% 34. 1H NMR(C6D6, 500 MHz) δ:
7.62-7.18 (m, 5H) 5.36-5.32 (q, 0.25H, CHdC, Z), 5.32-5.28
(q, 0.75 H, CHdC, E), 3.79-3.77 (q, 0.25H, HC-6â-DPSO, Z),
3,3-(Eth ylen edioxy)-6â-(DP SO)-5â-an dr ostan -17-on e (6).
The title compound was prepared by a procedure analogous
to that described for 5 above. Silylation of the alcohol 17 with
DPSCl in DMF-TEA afforded crude product that was purified
by the Chromatotron (20% EtOAc/hexane) and recrystallized
from hexane to afford white prisms, mp 139-143 °C. 1H NMR
(CDCl3, 300 MHz) δ: 7.76-7.36 (m, 5 H), 3.91-3.89 (s, 4 H),
3.73-3.66 (m, 1 H), 2.39-1.21 (m, 20 H), 1.17 (s, 3 H), 0.86 (s,
3 H), 0.38 (s, 3 H), 0.34 (s, 3 H). 13C NMR (CDCl3, 200 MHz)
δ: 221.30, 138.78, 133.32, 129.32, 127.70, 109.21, 72.85, 64.15,
64.04, 51.17, 47.85, 47.28, 40.37, 36.02, 35.80, 35.54, 34.67,
33.74, 31.61, 30.25, 29.68, 25.23, 21.55, 20.04, 13.81, -0.77,
-1.72. High resolution MS (EI) m/e: calcd 483.2931, found
483.2911.
6â-(DP SO)-5â-a n d r osta n -3-on e (8). The title compound
was prepared in five steps by a procedure analogous to that
used for the preparation of 5. The alcohol, 5-androsten-3â-ol,
was prepared by heating at reflux a mixture of 3â-hydroxy-
5-androsten-17-one (2.54 g, 8.81 mmol) in di(ethylene glycol)
(30 mL) with K2CO3 (1.0 g) and hydrazine hydrate (2.0 mL)
for several hours.26 The temperature was raised to 200 °C
overnight. After cooling, a white solid appeared that was
dissolved in a mixed solvent of ether and toluene. The organics
were washed with 5% HCl and water before drying. The ether
and toluene were removed under reduced pressure to give
5-androsten-3â-ol, which was used directly for the next step
without further purification.
The alcohol was oxidized with PCC for 2.5 h to give
5-androsten-3-one, which was purified on the Chromatotron
(15% EtOAc/hexane). The 3-CdO group was converted to the
ketal with excess 1,2-ethanediol and p-toluenesulfonic acid
monohydrate by refluxing in toluene overnight with ultimate
purification by flash column chromatography (some migration
of the olefin to the 3,4 position occurs; this material was
recycled). Hydroboration and oxidation of the ketal-protected
olefinic steroids produced a mixture of the 5â/6â and 5R/6R
alcohols that was deketalized with PdCl2. The 6â-hydroxy-
5â-androstan-3-one was partially purified using the Chroma-
totron (30% EtOAc/hexane). Silylation of the mixture with
3.76-3.73 (q, 0.75H, HC-6â-DPSO, E), 2.3-0.75 (m, incl.
s
at 1.24), 0.65 (s, 3 H), 0.35, 0.34 (s, 6 H). 13C NMR (CDCl3,
200 MHz) δ: 221.29, 139.11 and 138.88 (3-CdCHCH3, Z +
E), 133.31, 129.30, 127.69, 114.87, 73.10, and 73.05 (6â-CH-
OH, Z + E), -0.738, -1.642. MS EI m/e: calcd 450.2954,
found 450.2949.
P r ep a r a tive P h otolysis of 6â-(DP SO)-5â-a n d r osta n e-
3,17-d ion e (5) w ith 266 n m Ligh t. A degassed, stirred
solution of 5 (39.9 mg, 22.8 mM) in CH3CN (4.0 mL) was
irradiated at rt for 1.0 h with the 266-nm laser light (Nd:YAG,
4.0 mJ /pulse). Analysis of the irradiated solution by GC (12.5
m column; 263 °C) showed two major products at 5.64 and 5.83
min, a minor product at 13.63 min, and the starting material
at 6.79 min. Analysis by HPLC (100% CH3CN) indicated two
major products with tR ) 4.64 and 4.88 min and the starting
material at 5.43 min. The mixture was separated on the
Chromatotron (20% EtOAc/hexane) to give the enal (6â-
(DPSO)-3-oxo-13,17-seco-5â-androst-13-en-17-al, 18) (4 mg),
the epimer (6â-(DPSO)-5â,13R-androstane-3,17-dione, 19) (7
mg), and an isomeric mixture of the alcohols, 6â-(DPSO)-3R-
(â)-hydroxy-5â-androstan-17-one, 20, 21) (2 mg). In a second
experiment, the products were isolated using an analytical
C-18 HPLC column (initially 100% acetonitrile; second pass,
90 or 95% acetonitrile; 0.5 mL/min). Spectral data follow.
18. IR (CDCl3): 1714 (3-CdO) cm-1 1H NMR (CDCl3, 500
.
MHz) δ: 9.73- 9.70 (s, 1 H), 7.60-7.32 (m, 5 H), 3.73-3.68
(m, 1 H), 2.63-1.66; 1.53-1.16; 1.07-0.75 (m, 19 H), 1.65 (s,
3 H), 1.15 (s, 3 H), 0.36 (s, 3 H), 0.34 (s, 3 H). 13C NMR (CDCl3,
500 MHz) δ: 212.12, 202.20, 162.03, 138.06, 133.29, 130.62,
127.93, 129.05, 72.42, 48.92, 42.64, 41.81, 40.10, 36.90, 36.45,
35.11, 34.02, 33.27, 32.98, 23.97, 22.02, 21.50, 19.63, -1.22,
-1.76. MS (EI) m/e: 438 (M+), 423 (M - CH3), 361 (M -
C6H5), 135 (PhSi(CH3)2). MS (CI) m/e: 439 (M + H), 361 (M
- C6H6).
19. IR (CDCl3): 1712 (3-CdO), 1728 (17-CdO) cm-1
.
1H
NMR (CDCl3, 500 MHz) δ: 7.62-7.34 (m, 5 H), 3.69-3.65 (m,
1 H), 2.46-1.07 and 0.93-0.78 (m, 20 H), 1.04 (s, 3 H), 0.90
(s, 3 H), 0.35 (s, 3 H), 0.32 (s, 3 H). 13C NMR (CDCl3, 500
(26) Paquette, L. A.; Roberts, R. A.; Drtina, G. J . J . Am. Chem. Soc.
1984,106, 6690-6693.

Antenna-Initiated Photochemistry in Steroids
J . Org. Chem., Vol. 61, No. 20, 1996 7055
MHz) δ: 221.92, 211.91, 138.25, 133.22, 129.66, 127.91, 72.03,
50.03, 49.30, 41.98, 39.86, 36.93, 36.52, 35.28, 35.03, 33.88,
32.73, 32.13, 25.26, 24.67, 22.47, 21.38, -1.00, -1.82). MS
(EI) m/e: 438 (M+), 423 (M - CH3), 361 (M - C6H5), 135 (PhSi-
(CH3)2). MS (CI) m/e: 439 (M + H), 361 (M - C6H6). HRMS
CI m/e: calcd 439.2669, found 439.2678.
mixture of 33 and 34 (49 mg, 27.2 mM) in CH3CN (4.0 mL)
was irradiated at rt for 50 min with 266 nm light (Nd:YAG,
4.0 mJ /pulse). Analysis by GC (column C; 240 °C) showed two
pairs of major products with tR (min) ) 4.78 + 4.90 and 5.01
+ 5.20 min (starting materials at 5.89 and 6.13 min). The
products could not be separated on the Chromatotron and were
analyzed as a mixture (see the Results).
P h otolysis of 33 w ith 266 a n d 308 n m Ligh t. A degassed
solution of 33 (8.48 mM) in CH3CN was irradiated at rt for 1
min with 266 nm laser light (Nd:YAG, 4.0 mJ /pulse). Analysis
of the irradiated solution by GC (column C at 240 °C) showed
three photoproducts: the enal 6â-(DPSO)-3(E)-ethylidene-13,-
17-seco-5â-androst-13-en-17-al (35), 6â-(DPSO)-3(E)-ethylidene-
5â,13R-androstane-17-one (36), and the Z isomer of 33 (34) in
a ratio of 1.00:1.71:0.09. Photolysis at 308 nm gave the same
products with a similar ratio (1.00:1.77:0.13).
P h otolysis of 34 in CH 3CN w ith 266 a n d 308 n m Ligh t.
A degassed solution of 34 (7.58 mM) in CH3CN was irradiated
at rt for 1 min with 266 nm laser light (Nd:YAG, 4.0 mJ /pulse).
Analysis of the irradiated solution by GC (column C at 240
°C) showed three photoproducts: 6â-(DPSO)-3(Z)-ethylidene-
13,17-seco-5â-androst-13-en-17-al (37), 6â-(DPSO)-3(Z)-eth-
ylidene-5â,13R-androstan-17-one (38), and the E isomer, 6â-
(DPSO)-3(E)-ethylidene-5â,13R-androstan-17-one (33), in a
ratio of 1.00:2.81:0.24. Photolysis at 308 nm afforded the same
products in a ratio of 1.00:3.05:0.47.
Qu en ch in g Exp er im en ts for 5, 6, a n d 8 w ith cis-1,3-
P en ta d ien e. Six degassed solutions of 5 (11.4 mM) in CH3-
CN (1 mL) were photolyzed with the 266-nm laser (4.6 mJ /
pulse) for 7 min in the presence of cis-1,3-pentadiene (0, 60,
100, 200, 300, 500 mM). The relative efficiencies for loss of
starting material and the formation of photoproducts were
obtained by GC analyses (column B; 253 °C) with 3R-(DPSO)-
5R-androstane-11,17-dione as an internal standard. The data
20,21 (2.5:1). 1H NMR (CDCl3, 500 MHz) δ: 7.56-7.31 (m,
5 H), 4.14-3.26 (m, HC-3R(â)-OH, HC-6â-DPSO), 0.97 (s, 3
H), 0.93 (s, 3 H), 0.34-0.31 (s, 6 H). 13C NMR (CDCl3, 500
MHz) δ: 222, 74.0 (C-6â-DPSO: 3â-OH isomer), 73.33 (C-6â-
DPSO: 3R-OH isomer), 72.12 (C-3â-OH), 71.29 (C-3R-OH). MS
(EI) m/e: 440 (M+). MS CI m/e: 441 (M + H), 423 (M - H2O).
P h otolysis of 5 w ith TEA Usin g 266 n m Ligh t.
A
degassed solution of 5 (30.2 mg, 22.8 mM) and TEA (28 µL,
68.5 mM) in CH3CN (3.0 mL) was irradiated at rt for 2 h with
266-nm light (Nd:YAG, 4.0 mJ /pulse). Analysis of the irradi-
ated solution by GC (12.5 m column; 263 °C) showed the same
product mixture as was obtained without TEA. The spectra
for these products were likewise identical with those described
above.
Tim e Cou r se Stu d ies of th e P h otolysis of 5 w ith TEA
Usin g 266 n m Ligh t. A degassed solution of 5 (6.5 mg, 14.8
mM) and TEA (12 µL, 89.0 mM) in CH3CN (1.0 mL) was
irradiated at rt with 266-nm light (Nd:YAG, 4.0 mJ /pulse). The
photolysis was monitored by GC (12.5 m column; 263 °C) in
10 min intervals. The results are summarized in Table 1.
P h otolysis of 5 Usin g 308 n m Ligh t. A degassed solution
of 5 in CH3CN (10.56 mM) was irradiated at rt with 308-nm
light (YAG/dye, 3.7 mJ /pulse) for 5 min. The photolysis was
analyzed by GC (12.5 m column; 250 °C). The products were
the same as those formed in the 266-nm photolysis. A similar
photolysis in the presence of TEA gave identical results.
P r ep a r a t ive P h ot olysis of 3,3-(E t h ylen ed ioxy)-6â-
(DP SO)-5â-a n d r osta n -17-on e (6). A stirred, degassed solu-
tion of 6 (41.6 mg, 21.5 mM) in CH3CN (4.0 mL) was irradiated
at rt for 1 h with 266-nm light (Nd:YAG, 4.0 mJ /pulse).
Analysis by GC (column B; 263 °C) showed two major products
and the starting material (tR ) 7.04, 7.38, and 8.61 min,
respectively). Identical products were formed upon photolysis
with 308-nm light. The products could not be separated on
the Chromatotron; spectral analysis was therefore conducted
on a mixture of the enal, 3,3-(ethylenedioxy)-6â-(DPSO)-13,-
17-seco-5â-androst-13-en-17-al (22), and the epimer, 3,3-(eth-
ylenedioxy)-6â-(DPSO)-5â,13R-androstan-17-one (23), in a ra-
tio of ca. 1:2.0. Spectral data for the mixture: 1H NMR (CDCl3,
500 MHz) δ: 9.70-9.67 (s, 17-HCdO, enal), 7.63-7.32 (m),
3.99-3.84 (s, -OCH2CH2O-), 3.74-3.71 (q, HC-6â-DPSO,
enal), 3.71-3.68 (q, HC-6â-DPSO, epimer) (the ratio of inte-
grations of the two quartets is 1:2.0), 1.61 (s, 18-CH3CdC,
enal), 1.09 (s, 19-CH3, enal), 0.97 (s, 19-CH3, epimer), 0.94 (s,
18-CH3, epimer), 0.38 (s, Si-CH3, enal), 0.36 (s, Si-CH3, epimer),
0.34 (s, SiCH3, enal), 0.31 (s, SiCH3, epimer). 13C NMR (CDCl3,
500 MHz) δ: 222.42 (17-CdO, epimer), 201.78 (17-HCdO,
enal), 73.39, 73.01 (C-6â-DPSO, epimer, enal), 64.24, 64.08
(-OCH2CH2O-).
were corrected for absorption by the diene at 266 nm (ꢀ266
)
3.5 M-1 cm-1).3c,d Analogous experiments were run with 40
mM TEA.
A single point experiment was run with 6 (9.0 mM) and 100
mM cis-1,3-pentadiene. Analysis was as described above.
Likewise, 8 (10.6 mM) was photolyzed with 152 mM cis-1,3-
pentadiene with the 266 nm laser (3.4 mJ /pulse) and with 308
nm excimer laser (3.6 mJ /pulse) in the absence and presence
of TEA. The reactions were analyzed by GC on column C at
225 °C with 17â-(DPSO)-5R-androstan-3-one as an internal
standard.
P h otolysis of 5 in th e P r esen ce of Cyclop en ta n on e
a n d Cycloh exa n on e. Degassed solutions of 5 (10.8 mM) in
CH3CN (1.0 mL) with and without cyclopentanone (10.4 mM)
and cyclohexanone (10.5 mM) were irradiated at rt for 1 min.
The solutions were analyzed by GC on column C at 240 °C for
disappearance of the starting material and at 25 °C for loss of
the ketones.
Ack n ow led gm en t. This work was supported by the
National Science Foundation through Grant No. CHE-
9311828. We are grateful to Dr. Alex Siemiarczuk of
Photon Technology International, Inc., and Drs. Vijai
V. S. Tyagi and Martin J . vandeVen of ISS Corp. for
assistance in obtaining singlet lifetime data.
P r ep a r a tive P h otolysis of 6â-(DP SO)-5â-a n d r osta n -3-
on e (8). A stirred, degassed solution of 8 (35.6 mg, 21.0 mM)
in CH3CN (4.0 mL) was irradiated at rt for 2.0 h with 266-nm
light (Nd:YAG, 4.0 mJ /pulse). Analysis of the irradiated
solution by GC (column B; 253 °C) showed two major products
plus starting material (tR ) 3.20, 3.53, and 5.43 min, respec-
tively). Photolysis at 308 nm afforded the same results. The
two enals, 6â-(DPSO)-2,3-seco-5â-androst-1-en-3-al (26) and
6â-(DPSO)-3,4-seco-androst-4-en-3-al (27), were isolated as a
mixture on the Chromatotron (15% EtOAc/hexane) (2 mg) and
analyzed as such. 1H NMR (CDCl3, 500 MHz) δ: 9.92
(3-HCdO, 26), 9.43 (3-HCdO, 27), 5.67 (H2CdC<, 27), 5.03-
4.90 (-CHdCH2, 26).
Su p p or tin g In for m a tion Ava ila ble: Proton nuclear mag-
netic resonance spectra are provided for compounds 5, 6, 18,
19, the mixtures 20/21 and 33/34, and the alcohol precursor
to 8 (7 pages). This material is contained in libraries on
microfiche, immediately follows this article in the microfilm
version of the journal, and can be ordered from the ACS; see
any current masthead page for ordering information.
P r ep a r a tive P h otolysis of a Mixtu r e of 33 a n d 34 w ith
266 a n d 308 n m Ligh t. A stirred, degassed solution of a
J O952202X