Synthesis, biochemical evaluation and rationalisation of a series of 3,5- dibromo derivatives of 4-hydroxyphenyl ketone-based compounds as probes of the active site of type 3 of 17β-hydroxysteroid dehydrogenase (17β-hsd3) and the role of hydrogen bonding interaction in the inhibition of 17β-HSD3

Article abstract of DOI:10.2174/157018012800672994

We report the synthesis, evaluation and rationalisation of the inhibitory activity of a series of 3,5-dibromo derivatives of 4-hydroxyphenyl ketone as probes of the active site of the type 3 of 17β-hydroxysteroid dehydrogenase (17β-HSD3). The results support the important role of hydrogen bonding interaction in the inhibition of 17β-HSD3.

Full text of DOI:10.2174/157018012800672994

604
Letters in Drug Design & Discovery, 2012, 9, 604-610
Synthesis, Biochemical Evaluation and Rationalisation of a Series of 3,5-
Dibromo Derivatives of 4-Hydroxyphenyl Ketone-Based Compounds as
Probes of the Active Site of Type 3 of 17β-Hydroxysteroid Dehydrogenase
(17β-HSD3) and the Role of Hydrogen Bonding Interaction in the
Inhibition of 17β-HSD3
Moniola S. Olusanjo, Shreena N. Mashru, Timothy Cartledge and Sabbir Ahmed*
School of Science, Faculty of Science and Technology, University of the West of Scotland, High Street, Paisley,
Renfrewshire, Scotland, PA1 2BE, UK
Received February 17, 2012: Revised March 15, 2012: Accepted March 22, 2012
Abstract: We report the synthesis, evaluation and rationalisation of the inhibitory activity of a series of 3,5-dibromo
derivatives of 4-hydroxyphenyl ketone as probes of the active site of the type 3 of 17β-hydroxysteroid dehydrogenase
(17β-HSD3). The results support the important role of hydrogen bonding interaction in the inhibition of 17β-HSD3.
Keywords: Androgen ablation, Enzyme inhibition, Hydrogen bonding, 17β-hydroxysteroid dehydrogenase, Type 3.
INTRODUCTION
The biosynthesis of the more potent androgens (and
estrogens) from less potent steroids is catalysed by the 17β-
O
hydroxysteroid dehydrogenase (17β-HSD) family of
H
enzymes and involves the reduction of the C(17)=O moiety
to a C(17)-βOH group. The reduction reaction involves an
hydride transfer from the co-factor NADPH to the α-C(17)
O
position of the steroid together with proton transfer between
the amino acids at the active site and the C(17)-βO- resulting
in the formation of the β -hydroxy moiety [1] (Fig. 1). To
date, some 15 different types of 17β-HSD have been
reported and have been shown to be responsible for a
number of redox reactions [2]. For example, the conversion
of the weak androgen, androstenedione (AD), to the more
potent androgen testosterone (T), the principle precursor to
dihydrotestosterone (DHT) (which has been shown to be the
major mitogen in the prostate diseases such as benign
prostate hyperplasia and prostate cancer [3]) is catalysed by
the type 3 isozyme (17β-HSD3) [1]. A number of the types
of 17β-HSD family of enzymes also catalyse the oxidation
reaction, thereby resulting in a decrease in the potency of the
more potent sex steroid, for example, the type 2 form of 17β-
HSD family of enzymes has been shown to catalyse the
reverse oxidation of the more potent estrogens and
androgens, in particular, the oxidation of the C(17)-βOH
moiety to the C(17)=O functionality (Fig. 1) [1]. In the
treatment of hormone-dependent cancers such as prostate
and breast cancer, a decrease in the biosynthesis of these
potent steroids has been shown to lead to a major loss of
stimulation of the cancer cells, as such, the 17β-HSD family
of enzymes has become a major biochemical target in the
treatment of hormone-dependent cancers [4].
H-
O
17!-HSD2
OH
17!-HSD3
H
O
Fig. (1). α-Hydride (from NADPH) attack on the C(17) of AD in
the conversion of AD to T catalysed by 17β-HSD3 and type 2 of
17β-HSD (17β-HSD2).
In an effort to aid both the design of novel inhibitors and
the rationalisation of the inhibitory activity of known
inhibitors of this enzyme, we have previously undertaken the
derivation of the transition-state (TS) for type 1 17β-HSD
(17β-HSD1) [5], the enzyme which has been shown to
catalyse the biosynthesis of the more potent estrogen,
namely estradiol (E2), from estrone (E1). Using this
technique, we undertook the derivation of the TS for the
reaction catalysed by 17β-HSD3 (Fig. 2) since no crystal
structure exists currently for this enzyme. Using the derived
TS, we undertook a study where we superimposed a number
of known inhibitors of 17β-HSD3 onto the steroid backbone
*Address correspondence to this author at the School of Science, Faculty of
Science and Technology, University of the West of Scotland, High Street,
Paisley, Renfrewshire, Scotland, PA1 2BE, UK; Tel: +44-141-848-3000;
Fax: +44-141-848-3289; E-mail: sabbir.ahmed@uws.ac.uk
1875-628X/12 $58.00+.00
© 2012 Bentham Science Publishers

Synthesis, Biochemical Evaluation and Rationalisation
Letters in Drug Design & Discovery, 2012, Vol. 9, No. 6
605
Fig. (2). To show the TS for the reaction catalysed by 17β-HSD3 (substrate in red) [6].
Table 1. Inhibitory Data Obtained for the 4-Hydroxyphenyl Ketone-Based Compounds Previously Reported as Inhibitors of 17β-
HSD3 [12]
O
R
HO
Compound
R
% Inhibition [I]=100µM
1
2
-
38.8 ± 1.4
53.9 ± 1.1
-
3a
4a
5a
6a
7a
8a
9a
10a
11a
CH3
36.59 ± 0.52
53.03 ± 2.18
60.18 ± 0.77
61.81 ± 0.89
76.40 ± 0.18
80.26 ± 0.20
82.58 ± 0.49
83.53 ± 0.48
81.39 ± 0.09
C2H5
C3H7
C4H9
C5H11
C6H13
C7H15
C8H17
C9H19
and an aldehydic or ketone C=O group, with the carbonyl
moiety within the potential inhibitors being used to mimic
the C(17)=O of the AD backbone. We therefore designed,
synthesised and subsequently evaluated a number of 4-
hydroxyphenyl ketone-based compounds and rationalised the
inhibitory activity of these compounds [6, 7] (Table 1). From
our study, we also concluded the existence of a hydrogen
bonding group at the active site close to the C(15) and C(16)
position of the steroid backbone [7]. We hypothesised that it
was this additional H-bonding group which allowed the 4-
hydroxyphenyl ketone-based compounds to be orientated
within the active site such that the phenyl moiety was
positioned close to the C(15) and C(16) of the steroid
backbone, thereby allowing the OH of the inhibitor and the
active site to undergo hydrogen bonding interaction. We also
hypothesised that the alkyl chain (or indeed the cycloalkyl
moiety) within the inhibitors was involved in mimicking the
steroid carbon backbone, thereby allowing the inhibitors to
O
HO
HO
O
O
HO
O
OH
Baicalein (1)
7-Hydroxyflavone (2)
Fig. (3). Structures of the two alternative standards previously used
by other workers within the field and within the current study.
[6] and concluded from our study that the carbonyl moiety at
the C(17) position of the androgen precursor backbone was
an important feature in the mimicking of the substrate and
therefore an important feature for potential inhibition of 17β-
HSD3 [5, 6]. We therefore modelled a series of non-steroidal
compounds based on a backbone containing a phenyl ring

606 Letters in Drug Design & Discovery, 2012, Vol. 9, No. 6
Olusanjo et al.
possess the appropriate hydrophobicity. We also
hypothesised from our modelling study that the removal of
(or a reduction in the ability of the OH moiety within the 4-
hydroxyphenyl ketone based compounds to undergo) this
additional H-bonding interaction would potentially result in
a reduction in the inhibitory activity within the 4-
hydroxyphenyl ketone-based compounds. Here, in an effort
to evaluate our hypotheses with regard to the role of
interactions within the active site of 17β-HSD3, in particular,
the involvement of the hydrogen bonding interaction in the
inhibition of this enzyme, we undertook the synthesis of di-
brominated derivatives of a range of 4-hydroxyphenyl
ketone-based compounds, and their subsequent biochemical
evaluation against rat testicular microsomal enzyme using
radiolabelled AD as the substrate. In an effort to compare the
current range of compounds with our previous study, we
utilised two standard and known inhibitors of 17β-HSD3,
namely baicalein (1) and 7-hydroxyflavone (2) (Fig. 3)
which have both been previously shown to possess inhibitory
activity against this enzyme by us and other workers within
the field [8-10].
into diethyl ether (DEE) (2x50mL). The combined organic
layer was extracted into sodium hydroxide (NaOH, 2M)
(2x50mL) and then acidified to pH 2 using aqueous HCl
(1M, 40mL). The product was extracted into DEE
(2x50mL), the organic layer was washed with water
(2x50mL) and dried over anhydrous magnesium sulfate
(MgSO4). The solvent was removed under vacuum to give a
brown solid. Column chromatography of the crude solid
gave 3a as a white solid (1.6g, 73.5% yield); m.p.=109.4-
110.3oC (lit. m.p.=110.2-110.4oC [11]); Rf=0.35 [diethyl
ether (DEE)/petroleum spirit (40-60oC) (50:50)].
ν(max) (Film) cm-1: 3315.6 (OH), 1661.6 (C=O), 1605.3
(Ar C=C); δH (d6-Acetone): 9.20 (1H, s, OH), 7.89 (2H, dd,
J=8.9Hz, Ph-H), 6.91 (2H, dd, J=8.9Hz, Ph-H), 2.48 (3H, s,
CH3); δc (d6-Acetone): 196.36 (C=O), 162.63 (C-O), 131.57,
130.51, 115.97 (Ar, C), 26.34 (CH3); GC: tR=5.6min; LRMS
(m/z): 136 (M+, 41%), 121 (M+-CH3, 100%), 93 (M+-C2H3O,
28%); HRMS (ES): found 137.05971 C8H9O2 requires
137.15586; Elemental analysis: found C 70.42%, H 5.88%
C8H8O2 requires C 70.58%, H 5.92%.
4-Hydroxy-3,5-dibromoacetophenone (3b)
Bromine water was added to a solution of 3a (1.05g,
7.71mmol) in glacial acetic acid (15mL) and the mixture left
to stir for 3h. The mixture was extracted into DEE (2 x
50mL), washed with water (2 x 50mL) and dried over
anhydrous MgSO4. The solvent removed under vacuum gave
an off-white solid; recrystallisation (from 50% aqueous
ethanol) gave 3b as a white solid (1.47g, 64.4% yield);
m.p.=189-191ºC (lit. m.p.=187ºC [12]); Rf=0.60 [DEE/pet
spirit 40-60ºC (70/30)].
ν(max) (Film) cm-1: 3224.3 (Ph-OH), 1663.4 (C=O),
1581.5 (Ar C=C); δH (d6-Acetone): 8.13 (2H, s, Ph-H), 2.56
(3H, s, CH3); δC (d6-Acetone): 194.40 (CO), 154.89 (CO),
133.35 (CBr, Ar), 132.37 (CH, Ar), 110.08 (C, Ar), 26.16
(CH3); GC: tR=7.39min; LRMS (m/z): 294 (M+, 38%), 279
(M+-CH3, 100%), 251 (M+-C2H3O, 11%), 170 (M+-
C2H4BrO, 12%); HRMS (ES): found 292.8807 C8H7Br2O2
requires 294.94798.
EXPERIMENTAL
Methods and Materials
Chemicals were purchased from Sigma-Aldrich
Company Ltd (Poole, Dorset, England), and checked for
1
purity by H and 13CNMR (JEOL 400MHz and 100MHz
respectively) using either CDCl3, or d6-acetone as a solvent.
Infrared spectra were obtained on a Perkin-Elmer Fourier
Transform-Paragon 1000 IR. Gas chromatography-mass
spectrometry was carried out on a Hewlett Packard 5890
series II GC-MS at a flow rate of 0.58mL/min, and a
temperature range increasing from 120-270oC at the rate of
10oC/min. Melting points were uncorrected and were
obtained on a BUCHI 512 or a Gallenkamp Instrument.
Elemental analysis was undertaken at the School of
Pharmacy, London. Ultraviolet spectroscopy was carried out
on a CARY 100 Scan UV-visible spectrophotometer. All
non-radioactive steroids and laboratory reagents were analar
grade; β-nicotinamide adenine dinucleotide phosphate
(NADP, mono sodium salt), D-glucose-6-phosphate (mono
sodium salt), D-glucose-6-phosphate dehydrogenase
(suspension in ammonium sulfate) were obtained from
Roche Diagnostics, Lewes, East Sussex whilst 1 and 2 were
obtained from Sigma-Aldrich Company, Poole, Dorset.
[1,2,6,7-3H]AD was obtained from Amersham Pharmacia
Biotech UK Limited, Buckinghamshire. Optiscint HiSafe
was obtained from Perkin-Elmer Life and Analytical
Sciences, Beaconsfield, Bucks.
Preliminary Screening of Compounds for 17β-HSD3 [9]
All incubations were carried out in triplicate at 37oC in a
shaking water bath. Incubation mixtures (1mL), containing
NADPH-generating system (50µL), inhibitor (100µM,
20µL) and prepared substrate AD (1.5µM final
concentration, 15µL), in phosphate buffer (pH 7.4, 905µL),
were allowed to warm at 37oC. The testicular microsomes
were thawed and warmed to 37oC before addition
(0.097mg/mL final concentration, 10µL) to the assay
mixture. The solutions were incubated for 30 min at 37oC
and the reaction was quenched by the addition of ether
(2mL). The solutions were vortexed, then left to stand over
ice for 15min. The assay mixture was extracted with further
aliquots of ether (2 x 2mL) and the organic layers combined
into a clean tube before the solvent was evaporated. Acetone
(30µL) was added to each tube and vortexed thoroughly.
Aliquots, along with steroid carriers (AD and T, 5mg/mL,
approximately 10µL) were spotted onto TLC plates and run,
using a mobile phase consisting of dichloromethane (70mL)
and ethyl acetate (30mL). After development, the separated
steroids were identified, using a UV lamp, cut from the plate
Chemistry
1-(4-Hydroxy-phenyl)-ethanone (3a)
Aluminium chloride (4.5g, 33.8mmol) was added to a
solution of phenol (1.5g, 16.0mmol) in anhydrous
dichloromethane (DCM) (15mL). The slurry was left to stir
for 1h before acetyl chloride (1.3mL, 17.6mmol) was added
in a dropwise manner. The solution was left to stir for further
14h. The reaction was quenched using an ice-cold solution of
aqueous hydrochloric acid (HCl, 1M) (30mL) and extracted

Synthesis, Biochemical Evaluation and Rationalisation
Letters in Drug Design & Discovery, 2012, Vol. 9, No. 6
607
and placed into scintillation vials. Acetone (1mL) was added
to each vial in order to dissolve the steroid from the silica
plate and then scintillation fluid (Optiscint HiSafe) (3mL)
was added. The samples were vortexed and read for tritium
for 4 min per tube.
without any major problems. It should be noted that no
monobrominated by-product was observed, indeed, the
bromine was added in excess so as to prevent the production
of any monobrominated product – no other multiple
brominated (i.e. tri- or indeed tetra-brominated) derivatives
were observed. Although in general no major problems were
encountered in the synthesis of the target compounds, the
synthesis of 3b proved to be somewhat difficult and resulted
in a number of by-products which were produced in small
quantities – the target compound was obtained as a result of
an extensive series of column chromatography, however, the
synthesis of the remainder of the series proved to be less
challenging and without any major problems, presumably
due to the increased steric hindrance to the ortho positions
within the phenyl ring.
pKa Determination
The compounds (2-4mg) were added to borax buffer
(200mL), and the UV spectrum recorded between 200-
450nm. The absorbance of the major peak was then adjusted
to approximately 1 absorbance unit either by the addition of
more buffer or more of the specific compound. After
decanting the solution free of any undissolved phenolic
compound, 20mL of this stock solution was placed into 3
separate volumetric flasks (25mL) and filled up to the mark
with HCl (2M) (Aa), borax buffer pH 9.0 (A), or NaOH
(2M) (Ab). The UV spectrum of each solution was recorded
and the absorbance of each solution at the wavelength
corresponding to the NaOH (2M) (fully dissociated)
maxima, was determined. The pKa was then determined from
the calculation of the mole fraction [13].
From the consideration of the inhibitory activity data
(Tables 1 and 2), we observe that the dibrominated
derivatives of the 4-hydroxyphenyl-based compounds which
synthesised within the current study are extremely poor
inhibitors of 17β-HSD3, indeed, a number of compounds
showed no inhibitory activity (Table 2). The most potent
inhibitors within the range of compounds were 11b and 12b
which were both found to possess ~35% inhibition against
17β-HSD3 at [I]=100µM. Under similar conditions, the
parent non-brominated derivatives (compounds 3a to 11a,
Table 1) were found to be potent inhibitors of 17β-HSD3
[12] - 10a was found to inhibit this enzyme by ~84% under
similar conditions (and was found to possess an IC50 value of
7.84µM). In comparison, the two standard compounds were
also found to possess weak inhibitory activity against 17β-
HSD3 in comparison to compounds 3a to 11a with 1 and 2
possessing ~39% and ~54% inhibition (at [I]=100µM).
RESULTS AND DISCUSSION
In the synthesis of the 3,5-dibrominated derivatives of 4-
hydroxyphenyl ketone-based compounds (Scheme 1), the
latter series of compounds was initially synthesised
according to the literature methodology previously reported
by us via Friedal-Craft acylation [11]. Compounds 1a to 17a
were then derivatised to the target compounds involving the
use of bromine and glacial acetic acid as the reaction solvent
(Scheme 1) – the target compounds were therefore obtained
in good to excellent yield [ranging from ~53% for compound
8b (3,5-dibromo-4-hydroxyheptanophenone) to ~73% for
compound 5b (3,5-dibromo-4-hydroxypropiophenone)] and
As previously mentioned, the acidity of the phenolic OH
moiety was proposed to be an important factor in the
inhibitory activity observed in compounds 1a to 11a. In
particular, we proposed that the hydroxy moiety undergoes
hydrogen bonding interaction with an amino acid moiety
hypothesised to exist within the active site of 17β-HSD3
corresponding to the C(15) and C(16) area of the steroid
backbone. More specifically, we postulated that if the ability
of the OH moiety to undergo the hydrogen bonding
interaction was affected in any way, then this would result in
an overall decrease in the inhibitory activity observed within
these compounds. The consideration of the determination of
the pKa values for a small range of the dibrominated and the
non-brominated derivatives (Table 3) shows that the
dibromination of the phenyl ring moiety results in a
significant increase in the acidity of the OH moiety, as a
result, the dibrominated derivatives are found to possess
significantly reduced pKa values than the non-brominated
derivatives. For example, consideration of the inhibitory
activity of 10a and 10b shows that the two compounds
possess ~84% and ~23% inhibitory activity respectively
(under similar conditions) whilst possessing pKa values of
8.40 and 6.82 respectively, i.e. a dramatic increase in acidity
is observed in the dibrominated derivative. Similar trends are
observed in the other compounds (Table 3), for example,
compounds 3a and 3b are found to possess ~37% and 0%
inhibitory activity respectively (under similar conditions)
whilst possessing pKa values of 8.00 and 6.47 respectively.
The consideration of the pKa data for the dibrominated
HO
a
O
R
HO
b
O
Br
R
HO
Br
Scheme 1. Synthesis of dibrominated derivatives of 4-
hydroxyphenyl ketones as potential inhibitors of 17β-HSD
(a=various acid chlorides/AlCl3/DCM; b=Br2/CH3COOH/; R=C1 to
C12).

608 Letters in Drug Design & Discovery, 2012, Vol. 9, No. 6
Olusanjo et al.
Table 2. 3,5-Dibromo Derivatives of 3a to 17a Evaluated Against 17β-HSD3
O
Br
R
HO
Br
Compound
R
Initial Screening Against 17β-HSD3 at ([I]=100µM)
1
-
-
38.8 ± 1.4
53.9 ± 1.1
0
2
3b
CH3
4b
C2H5
0
5b
C3H7
0
6b
C4H9
0
7b
C5H11
C6H13
C7H15
C8H17
C9H19
C11H23
cycloC4H7
cycloC5H9
cycloC6H11
H
9.91±0.2
8.94±0.03
11.11±0.18
22.51±0.10
35.1±2.2
35.1±0.8
17.09±5.18
18.78±0.07
30.23±2.40
21.27±3.59
16.75±0.08
8b
9b
10b
11b
12b
13b
14b
15b
16b
17b
C6H5
Table 3. Table of pKa Values for a Small Range of Brominated and Non-Brominated Derivatives of 4-Hydroxypenyl Ketone-Based
Compounds
Compound
Experimentally Determined pKa Value
3a
4a
8.00
8.08
8.12
8.55
8.40
8.01
8.12
6.47
6.84
7.33
6.80
6.82
6.38
6.63
6a
8a
10a
17a
Average
3b
4b
6b
8b
10b
17b
Average

Synthesis, Biochemical Evaluation and Rationalisation
Letters in Drug Design & Discovery, 2012, Vol. 9, No. 6
609
derivatives would therefore appear to support our initial
hypothesis with regard to the importance of the OH moiety
in undergoing hydrogen bonding with the active site, i.e. an
increase in acidity within the 4-hydroxyphenyl ketone-based
inhibitors results in an overall decrease in inhibitory activity
against 17β-HSD3.
electron distribution within the dibrominated and the parent
compounds. The results of our additional molecular
modelling study show that the bromine atoms result in an
overall decrease in the electron density on the oxygen atom
of the OH moiety. For example, consideration of the
compounds 4a and 4b shows that within the former
compound, the partial charge on the oxygen atom of the
hydroxy moiety was found to be -0.221, whereas the oxygen
atom within compound 4b possessed a partial charge of -
0.187. That is, the dibromination of 4a resulted in an overall
decrease in electron density within the OH moiety, the
resulting decrease in electron density on the oxygen atom of
the OH functionality results in the resulting O- to be
stabilised within the dibrominated derivatives as opposed to
the non-brominated compounds. This therefore adds further
support that the brominated compounds are acidic in nature
compared to the non-brominated derivatives (hence resulting
in a decrease in pKa), as such, the potential for the OH
moiety to ‘donate’ the H to an appropriate amino acid within
the active site is decreased, thereby resulting in an overall
decrease in hydrogen bonding interaction between the
inhibitor and the active site (as well as a decrease in the
stability of the inhibitor enzyme complex), leading to an
overall decrease in inhibitory activity.
It could be argued that the dibromination of the phenyl
moiety could result in the OH moiety being sterically
hindered resulting in a decrease in the level of hydrogen
bonding interaction between the inhibitor and the active site.
As such, the observed reduction in inhibitory activity could
be postulated to be due to the steric effect of the two bromine
atoms as opposed to the increase in acidity. In an effort to
evaluate the role of the steric effect in comparison to the pKa,
we modelled the brominated and non-brominated derivatives
onto the previously reported TS for the reaction catalysed by
17β-HSD3, in particular, we minimised the inhibitors within
the representation of the active site so as to obtain the
binding conformer. The molecular modelling study shows
that the inhibitors are indeed able to fit within the active site
and undergo hydrogen bonding with the active site, as well
as undergo interaction with the NADPH functionality. For
example, the modelling of compound 10b (Fig. 4) shows that
the 4-hydroxy moiety is able to interact with the group at the
active site [which is postulated to exist close to the C(15)
and C(16) position of the steroid backbone] whilst still
undergoing the interaction between the NADPH and the
C=O moiety, resulting in a hydrogen bond distance of 2.2Ǻ.
The modelling study therefore suggests that the decrease in
inhibitory activity was due to the increase in acidity of the
OH moiety as opposed to the bromine atoms causing a steric
effect and therefore resulting in a decrease in the extended
hydrogen bonding (leading to a decrease in inhibitory
activity).
CONCLUSION
In conclusion, the biochemical evaluation of a series of
dibrominated and non-brominated derivatives of 4-
hydroxyphenyl ketone-based compounds adds further
support to our initial hypothesis that the hydroxy moiety
within the non-brominated range of compounds undergoes
hydrogen bonding interaction with the active site of 17β-
HSD3. Within the compounds considered in the current
study, we have also shown that the dibromination of the
parent compound (1a to 11a) resulted in an increase in the
acidity of the OH moiety, resulting in a disruption of the
In an effort to rationalise the increased acidity within the
dibrominated derivatives of the parent compounds (1a to
11a), we undertook a modelling study so as to determine the
Fig. (4). To show the modelling of 10b within the representation of the 17β-HSD3 active site.

610 Letters in Drug Design & Discovery, 2012, Vol. 9, No. 6
Olusanjo et al.
[2]
[3]
Luu-The, V.; Bélanger, A.; Labrie, F. Androgen biosynthetic
pathways in the human prostate. Best Pract. Res. Clin. Endocrinol.
Metab., 2008, 22, 207-221.
Bratoeff, E.; Ramírez, E.; Murillo, E.; Flores, G.; Cabeza, M.
Steroidal anti-androgens and 5 alpha-reductase inhibitors. Curr.
Med. Chem., 1999, 6, 1107-1123.
Poirier, D. Inhibitors of 17β-hydroxysteroid dehydrogenases. Curr.
Med. Chem. 2003, 10, 453-477.
Owen, C. P.; Ahmed, S. The derivation of a potential transition
state for the reduction reaction catalysed by 17β-hydroxysteroid
dehydrogenase (17β-HSD) – an approximate representation of its
active site for use in drug design and discovery. Biochem. Biophys.
Res. Comm. 2004, 318, 131-134.
Olusanjo, M. S.; Ahmed, S. The derivation of a potential transition-
state for the reduction reaction catalysed by 17β-hydroxysteroid
dehydrogenase type 3 (17β-HSD) – an approximate representation
of its active site for use in drug design and discovery Lett. Drug
Des. Disc. 2007, 4, 527-531.
Lota, R.; Dhanani, S.; Olusanjo, M.; Owen, C. P. and Ahmed, S.
Synthesis, biochemical evaluation and rationalisation of the
inhibitory activity of a range of 4-hydroxyphenyl ketones as potent
hydrogen bonding, leading to an overall reduction of the
inhibitory activity. The results of the current study would
therefore appear to support our hypothesis regarding the
importance of hydrogen bonding interaction in determining
the overall inhibitory activity of potential inhibitors of 17β-
HSD3 and therefore supports our previous observations [14].
[4]
[5]
DISCLOSURE
The overall conclusions in the two manuscripts
“Synthesis, biochemical evaluation and rationalisation of a
series of 3,5-dibromo derivatives of 4-hydroxyphenyl
ketone-based compounds as probes of the active site of type
3 of 17β-hydroxysteroid dehydrogenase (17β-HSD3) family
of enzymes – an insight into the importance of hydrogen
bonding interaction in the inhibition of 17β-HSD3” and
“Synthesis and Biochemical Evaluation of a Series of
Methanesulfonate Derivatives of 4-Hydroxyphenyl Ketone
as Probes of the Active Site of Type 3 OF 17β-
Hydroxysteroid Dehydrogenase Family of Enzymes” are
almost similar.
[6]
[7]
and specific inhibitors of the type
3 of 17β-hydroxysteroid
dehydrogenase (17β-HSD3) J. Steroid Biochem. Mol. Biol., 2008,
111, 128-137.
Le Lain, R.; Nicholls, P. J.; Smith, H. J.; Maharlouie, F. H.
Inhibitors of human and rat testes microsomal 17β-hydroxysteroid
dehydrogenase (17β-HSD) as potential agents for prostatic cancer.
J. Enzyme Inhib., 2001, 16, 35-45.
[8]
[9]
Lota, R.; Dhanani, S.; Owen, C. P.; Ahmed, S. Synthesis and
biochemical evaluation of a series of 4-hydroxyphenyl ketones as
potential inhibitors of 17β-hydroxysteroid dehydrogenase (17β-
HSD). Bioorg. Med. Chem. Lett., 2006, 16, 4519-4522.
Lota, R.; Dhanani, S.; Owen, C. P.; Ahmed, S. Search for potential
non-steroidal inhibitors of 17β-hydroxysteroid dehydrogenase
(17β-HSD). Lett. Drug Des. Disc., 2007, 4, 180-184.
Buehler, C. A.; Gardner, T. S.; Clemens, M. L. Parachor studies at
various temperatures J. Org. Chem., 1937, 2, 167-174.
Krausz F.; Martin R. Fries reaction 1–esters of phenols and certain
mono-substituted phenols. Bull. Soc. Chim. Fr. 1965, 2, 2192-2197.
Harwood L. M.; Moody C. J. In Experimental organic chemistry
principles and practice. 1996, pp716–719 Published by Blackwell
Science
CONFLICT OF INTEREST
Declared none.
[10]
ACKNOWLEDGEMENTS
[11]
[12]
[13]
The authors thank the elemental analysis service at the
School of Pharmacy, University of London (UK) for the
provision of elemental analysis data.
REFERENCES
[14]
Shah, K.; Olusanjo, M. S.; Cartledge, T.; Owen, C. P.; Ahmed, S.,
Lett. Drug Des. Disc., 2009, 6, 518-523..
[1]
Penning, T. M. Molecular determinants of steroid recognition and
catalysis in aldo-keto reductases. Lessons from 3α-hydroxysteroid
dehydrogenase. J. Steroid Biochem. Mol. Biol., 1999, 69, 211-225.