Synthesis and Structure-Activity Relationship Studies of Derivatives of the Dual Aromatase-Sulfatase Inhibitor 4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}phenyl sulfamate

Article abstract of DOI:10.1002/cmdc.201300015

4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}phenyl sulfamate and its ortho-halogenated (F, Cl, Br) derivatives are first-generation dual aromatase and sulfatase inhibitors (DASIs). Structure-activity relationship studies were performed on these

Full text of DOI:10.1002/cmdc.201300015

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DOI: 10.1002/cmdc.201300015
Synthesis and Structure–Activity Relationship Studies of
Derivatives of the Dual Aromatase–Sulfatase Inhibitor 4-
{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-
yl)amino]methyl}phenyl sulfamate
L. W. Lawrence Woo,[a] Paul M. Wood,[a] Christian Bubert,[a] Mark P. Thomas,[a] Atul Purohit,[b]
and Barry V. L. Potter*[a]
4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}phenyl
sulfamate and its ortho-halogenated (F, Cl, Br) derivatives are
first-generation dual aromatase and sulfatase inhibitors (DASIs).
Structure–activity relationship studies were performed on
these compounds, and various modifications were made to
their structures involving relocation of the halogen atom, intro-
duction of more halogen atoms, replacement of the halogen
with another group, replacement of the methylene linker with
a difluoromethylene linker, replacement of the para-cyano-
phenyl ring with other ring structures, and replacement of the
triazolyl group with an imidazolyl group. The most potent in
vitro DASI discovered is an imidazole derivative with IC50
values against aromatase and steroid sulfatase in a JEG-3 cell
preparation of 0.2 and 2.5 nm, respectively. The parent phenol
of this compound inhibits aromatase with an IC50 value of
0.028 nm in the same assay.
Introduction
In modern medicine, it is common practice to treat many dis-
eases concurrently with several drugs that target multiple bio-
logical targets via different mechanisms of action in order to
achieve the desirable therapeutic outcome concertedly. To this
end, an increasing number of clinically established drugs are
reformulated to give a fixed-dose dual-component medicine as
an alternative to co-administering the agents as two individual
drugs. While this approach is an obvious choice for attaining
a combined therapy, an attractive and more elegant strategy is
to design a single drug that inhibits more than one biological
target. In fact, the design of single agents that act against mul-
tiple biological targets is of increasing interest and promi-
nence. In recent years, an increasing volume of work has been
published exemplifying the successful use of this strategy.[1–11]
Breast cancer is a devastating disease that affects many
women from different age groups. When the disease is first di-
agnosed, about two-thirds of cases are classified as hormone-
dependent, in which the growth and development of tumours
are fuelled by oestrogens. Endocrine therapy is an effective
form of treatment for breast cancer of this type. The current
gold standard for treating patients with hormone-dependent
breast cancer is a selective oestrogen receptor modulator
(SERM) such as tamoxifen, which blocks the action of oestro-
gens on the oestrogen receptor. In addition, the inhibition of
aromatase, which leads to a decrease in the biosynthesis of
oestrogens, is well established as an effective form of endo-
crine treatment for breast cancer. The three aromatase inhibi-
tors (AIs) currently in clinical use for treating patients with ad-
vanced hormone-dependent breast cancer (HDBC) are letro-
zole, anastrozole, and exemestane. Various clinical trials in the
last decade have even advocated the use of these AIs in an
earlier clinical setting for treating primary breast cancer.[12–18]
However, inhibition of aromatase is not the only strategy avail-
able for decreasing the production of oestrogens. There is evi-
dence that inhibition of steroid sulfatase (STS), the enzyme
that converts the biologically inactive oestrone sulfate to oes-
trone,[19] may render significant oestrogen deprivation in pa-
tients treated with an STS inhibitor. The nonsteroidal com-
pound 1 (STX64, Irosustat, Figure 1) is the first STS inhibitor en-
tered into clinical trials.[20,21]
Because both aromatase and STS are involved in the synthe-
sis of biologically active oestrogens, it has been reasoned that
concurrent inhibition of these two enzymes in patients with
HDBC may lead to a more comprehensive oestrogen depriva-
tion and hence a better response to endocrine therapy. Our re-
search group has pioneered the approach of designing dual
aromatase and sulfatase inhibitors (DASIs) as a single agent for
inhibiting aromatase and STS concurrently. To date, we have
developed five structural classes of nonsteroidal DASIs. Briefly:
1) derivatives of the nonsteroidal AI 4-{(4-bromobenzyl)-
[1,2,4]triazol-4-ylamino}benzonitrile (e.g., 2–5, Figure 1);[22–25]
[a] L. W. L. Woo, P. M. Wood, C. Bubert, M. P. Thomas, B. V. L. Potter
Medicinal Chemistry, Department of Pharmacy and Pharmacology
University of Bath, Claverton Down, Bath BA2 7AY (UK)
E-mail: B.V.L.Potter@bath.ac.uk
[b] A. Purohit
Diabetes, Endocrinology & Metabolism, Imperial College London
Section of Investigative Medicine
6th Floor, Commonwealth Building (6N2B), Hammersmith Hospital
Du Cane Road, London W12 0NN (UK)
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analytical methods, and the purity of the compounds
tested in vitro was evaluated by HPLC.
The synthesis of sulfamates 11–13, 17–19 is out-
lined in Scheme 1. Following formation of the requi-
site benzyl alcohols 11 b, 12a, 13b, 17a, 18b, the
final three steps of the synthesis were identical for
each of the sulfamates. The appropriate benzyl alco-
hol was converted into the corresponding benzyl
chloride with thionyl chloride, and this was allowed
to react with 10 in N,N-dimethylformamide (DMF) in
the presence of potassium carbonate to give phenols
11 c, 12b, 13c, 17c, and 18d, respectively. The phe-
nols were converted into their corresponding sulfa-
mates with excess sulfamoyl chloride according to
the conditions described by Okada et al.[33] Benzyl al-
Figure 1. Structures of nonsteroidal steroid sulfatase inhibitor 1 (STX64, Irosustat) and
various structural classes of dual aromatase–sulfatase inhibitor (DASI) 2–9; X=OSO2NH2.
2) derivatives of letrozole (e.g., 6, Figure 1);[26–28] 3) derivatives
of anastrozole (e.g., 7, Figure 1);[29] 4) derivatives based on a bi-
phenyl template (e.g., 8, Figure 1);[30] and 5) a series of com-
pounds with a hybrid structure of experimental DASIs (e.g., 9,
Figure 1).[31] Herein we report the further expansion of the
series of DASIs 2–5. Inhibitory activities of new candidates
against aromatase and STS were evaluated in JEG-3 cells, and
structure–activity relationships (SAR) are discussed.
cohols 11 b and 13b were obtained from 2-fluoro- and 2,3-di-
fluoro-4-hydroxybenzoic acids, respectively, following conver-
sion into their methyl esters (with methanol/cat. HCl for 11 b
and methanol/SOCl2 for 13b) and reduction of these with lithi-
um aluminium hydride in tetrahydrofuran. From 2,6-difluoro-4-
hydroxybenzoic acid, benzyl alcohol 12a was obtained directly
following reduction with LiAlH4 in THF.
For the synthesis of compound 19, 3-bromo-4-methylphenol
was protected as the benzoate 19a and subsequently bromi-
nated with N-bromosuccinimide (NBS) under radical conditions
((BzO)2, CCl4) to afford 19b. Benzyl bromide 19b was used to
alkylate the deprotonated form of 10 to give the benzoate
19c, which was hydrolysed with potassium hydroxide in meth-
anol to the phenol 19d. Phenol 19d was treated with excess
sulfamoyl chloride in N,N-dimethylacetamide (DMA) to give 19.
The route to sulfamate 14 starting from diethyl-2-(2,6-di-
fluoro-4-methoxyphenyl)malonic acid,[34] which was itself syn-
thesised by the reaction of diethyl malonate with 4-bromo-3,5-
difluoroanisole, is shown in Scheme 2. The diester was hydro-
Results and Discussion
Chemistry
The preparation of 4-[(4-cyanophenyl)amino]-4H-1,2,4-triazole
(10, Scheme 1) was carried out according to Okada et al.[32] All
of the novel sulfamates and phenols described herein were
prepared according to the schemes described below. The final
compounds and intermediates were characterised by standard
Scheme 1. Synthesis of compounds 11–13 and 17–19. Reagents and conditions: a) MeOH, HCl (cat.), reflux, 78%; b) LiAlH4, THF, RT, 76–94%; c) SOCl2, MeOH,
reflux, 100%; d) NaBH4, EtOH/H2O, RT, 93%; e) SOCl2, RT; f) 10, K2CO3, DMF, RT, 15–100%; g) H2NSO2Cl, DMA, 08C!RT, 55–95%; h) BzCl, py, RT, 75%; i) NBS,
(BzO)2, CCl4, reflux, 51%; j) 10, NaH, DMF, RT, 85%; k) KOH, MeOH, 52%.
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benzyl alcohol was converted
into the corresponding benzyl
bromide with phosphorus tribro-
mide in dichloromethane. This
was subsequently used to alky-
late the sodium hydride generat-
ed anion of 10 to furnish 15 f.
Removal of the TIPS protecting
group was carried out with TBAF
in THF, and the resulting phenol
15g was converted into sulfa-
mate 15 under the conditions
previously described.
Sulfamate 16 was prepared
from 4-benzyloxybenzoic acid
according to the route illustrated
in Scheme 4. Following prepara-
Scheme 2. Synthesis of compound 14. Reagents and conditions: a) 3m NaOH, reflux, 88%; b) 1608C, 93%;
c) MeOH, HCl (conc.), reflux, 92%; d) BBr3, CH2Cl2, ꢀ788C!RT, 77%; e) TIPSCl, imidazole, DMF, RT, 91%; f) LiAlH4,
THF, 08C, 62%; g) PPh3, CBr4, CH2Cl2, 08C!RT, 67%; h) 10, NaH, DMF, RT; i) TBAF, THF, RT, 41%; j) H2NSO2Cl, DMA,
08C!RT, 53%.
lysed to diacid 14a with 3m sodium hydroxide, and this decar-
boxylated following heating at 1608C to give 14b. The acid
was converted into methyl ester 14c, and the phenol was de-
methylated following treatment with boron tribromide in di-
chloromethane and then re-protected with triisopropylsilyl
chloride (TIPSCl) to furnish 14e. The methyl ester was reduced
with LiAlH4 to give alcohol 14 f, which was converted into the
corresponding bromide following treatment with PPh3/CBr4 in
dichloromethane. This was subsequently used to alkylate the
Scheme 4. Synthesis of compound 16. Reagents and conditions: a) SOCl2,
reflux, then 10, Et3N, CH2Cl2, RT, 67%; b) Lawesson’s reagent, xylenes, reflux,
56%; c) Deoxo-Fluorꢁ, SbCl3, CH2Cl2, RT, 71%; d) H2, Pd/C (10%), THF/MeOH,
RT, 61%; e) H2NSO2Cl, DMA, 08C!RT, 76%.
sodium hydride generated anion of 10. Removal of the TIPS
protecting group was achieved with tetra-n-butylammonium
fluoride (TBAF) in THF, and the resulting phenol 14h was con-
verted into sulfamate 14 under the conditions previously de-
scribed.
Sulfamate 15 was prepared in seven steps (Scheme 3) from
3-formyl-4-hydroxybenzoic acid methyl ester 15a, which was
prepared from methyl 4-hydroxybenzoate as described by Hof-
sløkken and Skattebol.[35] Starting material 15a was fluorinated
with Deoxo-Fluorꢁ to give phenol 15b, which was then TIPS-
protected to furnish 15c. Reduction of the ester was success-
fully achieved with lithium borohydride, and the resulting
tion of the acid chloride with thionyl chloride, reaction with 10
gave amide 16a. The amide was converted into the corre-
sponding thioamide with Lawesson’s reagent in xylenes at
reflux, and this was fluorinated with Deoxo-Fluorꢁ in the pres-
ence of catalytic antimony trichloride to give 16c.[36] Deprotec-
tion of the phenol was achieved by catalytic hydrogenation
with palladium on charcoal to give 16d, and the formation of
the corresponding sulfamate
was achieved using the condi-
tions previously described to
give 16.
The trio of sulfamates 20, 21,
and 22 were prepared according
to the route described in
Scheme 5 by starting from com-
mercially available aniline, 5-
amino-2,2-difluoro-1,3-benzo-
dioxole, and 3,5-difluoroaniline,
respectively. Each amine was
condensed with 4-benzyoxyben-
zaldehyde to give imines 20a,
21a, and 22a, which were sub-
sequently reduced with sodium
Scheme 3. Synthesis of compound 15. Reagents and conditions: a) Deoxo-Fluorꢁ, EtOH, CH2Cl2, RT, 75%; b) TIPSCl,
imidazole, DMF, RT, 99%; c) LiBH4, B(OMe)3, Et2O, RT, 67%; d) PBr3, CH2Cl2, 08C!RT, 76%; e) 10, NaH, DMF, 08C!
RT, 74%; f) TBAF, THF, RT, 95%; g) H2NSO2Cl, DMA, 08C!RT, 90%.
borohydride to give amines 20b,
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Scheme 5. Synthesis of compound 20, 21 and 22. Reagents and conditions: a) 4-benzyloxybenzaldehyde, p-TsOH, EtOH, reflux, 78–85%; b) NaBH4, EtOH/H2O,
08C!RT, 94–96%; c) NaNO2, H2O, CHCl3, 2m H2SO4, 08C, then LiAlH4, THF, RT, 72–86%; d) dimethylformamide diazine dihydrochloride, py, reflux, 53–70%;
e) H2, Pd/C (5%), THF/MeOH, RT, 74–92%; f) H2NSO2Cl, DMA, 08C, 27–75%.
21b, and 22b. The triazole ring was constructed stepwise, first-
ly by treating the requisite amines with sodium nitrite and
then with LiAlH4 to give hydrazines 20c, 21c, and 22c. This
was followed by treatment of the hydrazines with dimethylfor-
mamide diazine dihydrochloride in pyridine at reflux[37] to fur-
nish 20d, 21d, and 22d. The benzyl group was removed by
catalytic hydrogenation with palladium on charcoal, and finally
the phenol was sulfamoylated under the conditions described
above to give compounds 20, 21, and 22.
was obtained by converting 11 b into the benzyl ether 25a
and subsequent treatment of 25a with thionyl chloride in di-
chloromethane. Benzyl chloride 25b was used to alkylate the
sodium hydride generated anion of 24 to afford 25c. The
benzyl group of 25c was removed by catalytic hydrogenation
with palladium on charcoal, and finally the phenol 25d was
converted into sulfamate 25 by using the conditions described
above.
The synthesis of compound 25 is shown in Scheme 6. 4-(1H-
Imidazol-1-ylamino)benzonitrile (24) was prepared in two steps
following a patent procedure.[38] Commercially available 4-cya-
nophenylhydrazine hydrochloride was allowed to react with 2-
isothiocyanato-1,1-dimethoxyethane in acetic acid and water
at 1008C to give 23, which was then treated with hydrogen
peroxide in acetic acid to afford 24. The benzyl chloride 25b
Biological assays
The in vitro inhibition of aromatase and STS activity by each
sulfamate was measured in a preparation of an intact monolay-
er of JEG-3 cells. The results are reported as IC50 values and are
compared with those of published data for DASIs 2–5
(Table 1). We also tested the in vitro inhibition of aromatase by
parent phenols in the same manner. The results are
listed in Table 2 and are compared with published
data for compounds 2a–5a.
1) Sulfamates
Although their potency against an individual enzyme
is not as high as that observed for the single agent
AI letrozole (IC50 =0.89 nm, JEG-3),[25] and STS inhibi-
tor 1 (IC50 =1.5 nm, JEG-3),[23] reference compounds
2–5 are first-generation DASIs that show significant
dual inhibition against aromatase and STS. A prelimi-
nary SAR study for these compounds established,
among other things, that a halogen atom substituted
at the ortho position to the sulfamate group contrib-
utes significantly to the biological activities observed
for these compounds and that the sulfamate group
positioned para to the methylene linker between the
arylsulfamate motif and the 4-(4H-1,2,4-triazol-4-yla-
mino)benzonitrile moiety is crucial for potent STS in-
Scheme 6. Synthesis of 25. Reagents and conditions: a) AcOH/H2O (10:1), 1008C, 1 h,
80%; b) AcOH, 50% H2O2, 08C, 59%; c) BnBr, K2CO3, DMF, RT, 84%; d) SOCl2, CH2Cl2, RT,
85%; e) NaH, DMF, RT, 85%; f) H2, Pd/C (5%), THF/MeOH (1:1), 81%; g) H2NSO2Cl, DMA,
08C!RT, 88%.
hibition.[23] The SAR for this class of DASIs is further
expanded in this work.
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ortho-halogenated counterparts
3, 4, and 5 (fluorinated deriva-
tives: 3, IC50 =40 nm vs. 11,
IC50 =21 nm; chlorinated deriva-
tives: 4, IC50 =20 nm vs. 17,
IC50 =40 nm; brominated deriva-
tives: 5, IC50 =39 nm vs. 19,
IC50 =29 nm).
Table 1. In vitro inhibition of the aromatase and STS activity in a JEG-3 cell preparation by compounds 11–22
and 25; compounds 2–5 are included as reference.[23]
b) m,m’-Dihalogenated deriva-
tives 12 and 18
Introduction of the same halo-
gen atom at the remaining meta
position to the sulfamate group
of 11 (m-F) and 17 (m-Cl) to give
the respective dihalogenated de-
rivatives 12 (m-F, m’-F) and 18
(m-Cl, m’-Cl) significantly im-
proves the inhibitory activity
against aromatase (fluorinated
derivatives: 11, IC50 =39 nm vs.
12, IC50 =1.3 nm; chlorinated de-
rivatives: 17, IC50 =18 nm vs. 18,
IC50 =0.6 nm). In addition, 12
and 18 are apparently even
more potent AIs than the ortho-
halogenated compounds 3 (o-F,
IC50 =12 nm) and 4 (o-Cl, IC50 =
2.3 nm). The higher lipophilicity
anticipated for 12 and 18 might
contribute to their greater po-
tency observed for aromatase in-
hibition.
Compd[a]
R1
R2
R3
R4
Aromatase IC50 [nm]
STS IC50 [nm]
2
3
4
5
H
F
Cl
Br
H
H
F
–
F2HC
–
H
H
H
H
F
–
–
H
H
H
H
F
F
F
–
H
–
Cl
Cl
Br
H
H
–
H
H
H
H
H
F
H
–
H
–
H
Cl
H
H
F
H
H
H
H
H
H
H
–
H
–
H
H
H
–
100
12
2.3
0.82
227
40
20
39
11
12
13
14
15
16
17
18
19
20
21
22
25
39ꢁ2.8
1.3ꢁ0.3
7.1ꢁ1.7
4.0ꢁ0.72
4.4ꢁ0.1
1013ꢁ13
18ꢁ2
21ꢁ3.5
39ꢁ1
48ꢁ2
485ꢁ50.7
60ꢁ2.4
190ꢁ20
40ꢁ5
44ꢁ6
29ꢁ2
1557ꢁ116
45 ꢁ5
52ꢁ6.6
2.5ꢁ0.4
0.6ꢁ0.1
2.6ꢁ0.3
2483ꢁ189
760ꢁ110
4060ꢁ260
0.2ꢁ0.01
–
–
–
–
–
–
[a] X=OSO2NH2.
a) m-Halogenated derivatives 11, 17, and 19
Unexpectedly, 12 and 18 show a similar potency to 3, 4, 11,
and 17 in their activities against STS. They all inhibit STS with
IC50 values ranging between 20 and 44 nm. We have demon-
strated repeatedly in previous SAR studies that the STS inhibi-
tory activity of an aryl sulfamate can generally be increased by
lowering the pKa value, and hence improving the leaving
group ability, of its parent phenol.[22–25,27–31,39] Because of the
electron-withdrawing effect on the sulfamate group exerted by
the halogens at the m,m’-position, the pKa values of parent
phenols 12b and 18c are predicted to be between 0.4 and 1.0
log units lower than those of phenols 3a, 4a, 11 c, and 17c (as
calculated by ACD/Labs v11.02 and based on comparison be-
tween respective mono- and dihalogenated para-cresols). The
fact that 12 and 18 are not more effective STS inhibitors than
3, 4, 11, and 17, as predicted, suggests their STS inhibitory ac-
tivities observed might be influenced by other factors.
The first modification made to DASIs 3, 4, and 5 was the relo-
cation of their halogen atom from the ortho to the meta posi-
tion to the sulfamate group to give derivatives 11 (m-fluoro),
17 (m-chloro), and 19 (m-bromo), respectively. As shown in
Table 1, this modification decreases the ability of the deriva-
tives to inhibit aromatase (fluorinated derivatives: 3, IC50 =
12 nm vs. 11, IC50 =39 nm; chlorinated derivatives: 4, IC50 =
2.3 nm vs. 17, IC50 =18 nm; brominated derivatives: 5, IC50 =
0.82 nm vs. 19, IC50 =2.6 nm). These results suggest that substi-
tution of a single halogen atom on the sulfamate-bearing
phenyl ring in this class of DASIs is more effective for inhibiting
aromatase if it is made at the ortho position to the sulfamate
group. Like the ortho-halogenated derivatives 3, 4, and 5, the
fluoro derivative 11 is less potent than the chloro derivative
17, which in turn is a weaker AI than the bromo derivative 19.
This ascending order of potency against aromatase observed
might be related to the increase in lipophilicity of the com-
pounds as the size of the halogen increases from fluorine to
bromine. The relocation of a halogen from the ortho to the
meta position to the sulfamate group does not affect the STS
inhibitory activity significantly, as meta-halogenated com-
pounds 11, 17, and 19 inhibit STS to a similar extent as their
c) o,m-Difluorinated derivative 13
When the two fluoro atoms are substituted on the same side
of the phenyl ring at the ortho and meta positions to the sulfa-
mate group, the resulting derivative 13 (o-F, m-F, IC50 =7 nm)
inhibits aromatase about fivefold less effectively than 12 (m-F,
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m’-F, IC50 =1.3 nm), although their STS inhibitory activities are
similar (12, IC50 =39 nm and 13, IC50 =48 nm). The dual inhibi-
tory activity observed for 13 is similar to that of 3 (o-F,
IC50 arom. =12 nm and IC50 STS =40 nm). These results suggest that
disubstitution of fluorine atoms is more effective for aromatase
inhibition, but not for STS inhibition, if they are substituted at
the m,m’-position rather than at the o,m-position on the sulfa-
mate-bearing phenyl ring.
cantly decreases the inhibitory activity of 16 (IC50 arom. =
1013 nm, IC50 STS =190 nm) against aromatase, but acts to main-
tain a level of STS inhibition similar to that observed for 2
(IC50 arom. =100 nm, IC50 STS =227 nm). These results suggest that
the difluoromethylene motif is tolerated by STS, but not by ar-
omatase, when it replaces the methylene group as the linker
between the aryl sulfamate motif and the 4-(4H-1,2,4-triazol-4-
ylamino)benzonitrile moiety.
d) o-Difluoromethyl derivative 15
f) Replacement of the para-cyanophenyl ring of 2 with other
entities (20, 21, and 22)
A previous SAR study had shown that 2-difluoromethyloes-
trone 3-O-sulfamate is a potent steroidal STS inhibitor with an
IC50 value of 100 pm against STS in a placental microsome
preparation.[40] It was reasoned that the electron-withdrawing
effect of the 2-fluoromethyl group, as well as the potential of
the fluorine atoms to form hydrogen bonds with residues
lining the catalytic active site of STS, are contributive factors to
the high potency observed. To explore the effect of the difluor-
omethyl group on the STS and aromatase inhibitory activity of
this class of DASIs, the ortho-fluoro atom of 3 was replaced
with a difluoromethyl group. As shown in Table 1, the difluoro-
After varying the substitution pattern of halogens on the sulfa-
mate-bearing aryl ring and modifying the alkylene linker in this
class of compounds, the para-cyanophenyl ring of 2 was modi-
fied first by replacing its para-cyano group with a hydrogen
atom to give 20, and then by replacing the ring altogether
with
a 3,5-difluorophenyl ring or a 2,2-difluorobenzo[d]-
[1,3]dioxol-5-yl moiety to give 21 and 22, respectively.
As shown in Table 1, replacement of the cyano group of 2
with a hydrogen atom is clearly detrimental to dual inhibitory
activity. The IC50 values of 20 for aromatase (2483 nm) and STS
(1557 nm) inhibition are an order of magnitude higher than
those observed for 2 (IC50 arom. =100 nm, IC50 STS =227 nm). A
previous SAR study on nonsteroidal AIs that are based on a bi-
phenyl template (e.g., 8, Figure 1) demonstrated that a cyano
group substituted at the position on the phenyl ring para to
a haem-ligating moiety, such as the triazolylmethyl group, is
important for potent aromatase inhibition.[41] Either the remov-
al of the cyano group or the replacement of it with a fluorine
or a chlorine atom leads to derivatives that are significantly
weaker AIs.[41] Docking studies on this class of biphenyl-based
AIs into a homology model of human aromatase (PDB code:
1TQA) revealed that the cyano group might interact favourably
with Ser478 of the active site through hydrogen bond interac-
tions.[41]
methyl group improves aromatase inhibition, as 15 (IC50 arom.
=
4.4 nm) is threefold more potent than 3 as an AI. However,
contrary to expectation, there is no apparent improvement on
STS inhibition observed with 15, showing an IC50 value of
60 nm against STS, compared with 40 nm for 3. It is possible
that the more flexible structure of this class of DASIs, in con-
trast to the more rigid backbone of a steroidal STS inhibitor,
does not align the 2-difluoromethyl group effectively for fa-
vourable interactions within the STS active site.
e) Derivatives with an ethylene linker (14) and a difluoro-
methylene linker (16)
When the methylene linker between the arylsulfamate motif
and the 4-(4H-1,2,4-triazol-4-ylamino)benzonitrile moiety of 12
was replaced by an ethylene group, such an extension de-
creases both the aromatase and STS inhibitory activities of the
resulting derivative 14, with the potency against STS more sig-
nificantly impaired (12, IC50 arom. =1.3 nm, IC50 STS =39 nm vs. 14,
IC50 arom. =4 nm, IC50 STS =485 nm). A similar adverse effect on
STS inhibition is observed when the methylene linker of 2–5 is
replaced by either an ethylene or a propylene group; in con-
trast, however, a much improved or at least similar inhibition
of aromatase was observed for the ethylene derivatives of 2–
5.[24]
In addition to elongating the methylene linker of 12, the
methylene linker of 2 was replaced with difluoromethylene to
give 16. We reasoned that this electron-withdrawing motif
would, on the one hand, lower the pKa of the parent phenol
16d and hence improve the ability of sulfamate 16 to inhibit
STS; on the other hand, the two fluoro atoms should increase
the lipophilicity of the derivative and hence make a relative im-
provement of the aromatase inhibition by 16 (clogP 0.875, cf.
0.179 for 12, as calculated by ChemBioDraw Ultra v12.0.2).
However, against some expectations, this modification signifi-
In addition to its positive effect on aromatase inhibition, the
para-cyano group is apparently also important for STS inhibi-
tion, as 20 is some sevenfold weaker as an inhibitor than 2. It
is possible that the para-cyano group of 2 functions as a hydro-
gen bond acceptor and interacts favourably with amino acid
residue(s) lining the enzyme active site of STS, allowing
a better binding affinity of 2 to the enzyme active site than 20.
Replacement of the para-cyanophenyl group of 2 with a 3,5-
difluorophenyl ring or a 2,2-difluorobenzo[d][1,3]dioxol-5-yl
moiety produces much weaker AIs, although the ability of 21
(IC50 =760 nm) to inhibit aromatase is better than that of 22
(IC50 =4060 nm), suggesting that the 3,5-difluorophenyl ring in-
teracts better with the aromatase active site than the 2,2-
difluorobenzo[d][1,3]dioxol-5-yl moiety. However, both 21
(IC50 =45 nm) and 22 (IC50 =52 nm) are more potent STS inhibi-
tors, with activities an order of magnitude higher than that of
2 (IC50 =227 nm). These results suggest that while the 3,5-di-
fluorophenyl ring and the 2,2-difluorobenzo[d][1,3]dioxol-5-yl
moiety do not improve aromatase inhibition, they confer fa-
vourable properties to 21 and 22 for a stronger binding of the
compounds to the active site of STS. From this SAR study, it
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can be concluded that the para-cyanophenyl ring provides the
proaching closer to the iron. The sulfamate group of both 11
and 25 points towards Ser478 and Asp309. Hydrogen bonds
(within 2.5–2.6 ꢂ) are anticipated between the sulfamate nitro-
gen atom and the backbone carbonyl group of Asp309, and
also between one of the sulfamate oxygen atoms and the side
chain hydroxy group of Ser478. The cyano group of both com-
pounds points towards the same region of space as the C17
carbonyl group of androstenedione, where it may interact with
the backbone NH of Met374 as a hydrogen bond acceptor.
These docking results of 11 and 25 show the two compounds
could potentially bind to active site of aromatase and interact
with neighbouring amino acid residues, although the preferred
docking poses observed cannot explain the superior aromatase
inhibition observed for 25.
For STS inhibition, 25 is a potent inhibitor in JEG-3 cells
(IC50 =2.5 nm) with potency similar to that of STS inhibitor
1 (IC50 =1.5 nm). However, it is not evident why replacing the
triazolyl group with an imidazole renders such a significant in-
crease in STS inhibition over that observed for 11. The docking
of 11 and 25 into the crystal structure of human STS[44] does
not reveal any significant difference in their poses. As shown in
Figure 3, 11 and 25 bind similarly to STS. Their sulfamate
best balanced dual inhibition for this class of DASIs.
g) Imidazole derivative 25
The most potent DASI studied in this work is compound 25,
the respective IC50 values of which against aromatase and STS
are 0.2 and 2.5 nm. Compared with 11 (IC50 arom. =39 nm,
IC50 STS =21 nm), the replacement of its triazole moiety with an
imidazole to give 25 improves both the aromatase and STS in-
hibitory activities by two orders and one order of magnitude,
respectively. (Note: In their patent application, Lafay et al. cited
compounds of similar structural features which also possess
potent dual inhibition of aromatase and STS.)[38]
The increase in aromatase inhibition observed for 25 is not
unexpected, as imidazole (pKBH+ =7.0) is a stronger Lewis base
than a triazole (pKBH+ =2.2). The lone-pair electrons on the sp2
nitrogen atom of an imidazole are more readily available for li-
gating to the haem iron centre than the equivalent in a triazole.
Therefore, with other structural features being the same, it is
anticipated that an imidazole-containing AI will inhibit aroma-
tase more strongly than its triazole-containing counterpart.
To explore how 25 may interact with the active site of aro-
matase, we docked the compound and its triazole congener
11 into the crystal structure of human aromatase that had
been co-crystallised with androstenedione.[42,43] Like previous
docking studies performed for structurally similar AIs, a distance
constraint was set between the haem iron and the ligating ni-
trogen atom in this work. As shown in Figure 2, the preferred
docking poses of 25 (yellow) and 11 (pink) are similar with
their heterocycles position under the haem. One small differ-
ence observed is that the imidazole group of 25 is 0.1 ꢂ fur-
ther away from the haem than the triazole group of 11. This is
probably due to steric hindrance posed by the CH group of
the imidazole ring of 25 preventing the heterocycle from ap-
Figure 2. Docking of compounds 11 (pink carbon atoms) and 25 (yellow
carbon atoms) into the crystal structure of human aromatase co-crystallised
with androstenedione. Selected protein residues are shown with green
carbon atoms. The haem is shown with purple carbons, and the iron as
a brown sphere. The crystal structure androstenedione has blue carbon
atoms. Potential hydrogen bonds are indicated by dashed black lines.
Figure 3. The docking of 11 (cyan) and 25 (pink) into the crystal structure of
human STS. Selected protein residues are shown with green carbon atoms.
The Ca2+ ion is depicted as a yellow sphere, and FG75 (purple) is a gem-diol
form of formylglycine residue 75.
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groups interact with FGly75, His290, Lys368, and the calcium
ion, whereas their cyano groups point towards the guanidini-
um group of Arg98. The phenyl ring to which their cyano
group is attached may have a face–edge interaction with the
ring of Phe488. Despite their different orientations in the dock-
ing poses, the imidazole of 25 and the triazole of 11 share the
same region of space and may
), 17c (m-Cl), 19d (m-Br), and 25d (imidazole) follow this gen-
eral observation, with 12b (m-F, m’-F), 13c (o-F, m-F), 18c (m-
Cl, m’-Cl), 20e (phenyl), 21e (3,5-difluorophenyl), and 22e (2,2-
difluorobenzo[d][1,3]dioxol-5-yl) showing aromatase inhibition
either similar to or less potent than their corresponding sulfa-
mates (Table 2).
form hydrogen bonds with one
Table 2. In vitro inhibition of aromatase activity in a JEG-3 cell preparation by parent phenols described in this
work; compounds 2a–5a are included as reference.[23]
or both of Gly100 and Thr99.
Despite the relatively high in
vitro potency observed for AIs
that contain an imidazole group
as the haem-ligating species, it
is worth noting that all nonster-
oidal AIs currently in clinical use
are solely triazole derivatives. Al-
though to the best of our
knowledge the preference in
featuring a triazole over an imi-
dazole as the haem-ligating spe-
cies is not clear, one possibility
is that triazole compounds are
metabolically more stable than
their imidazole counterparts
in vivo.[45] It is also possible that
triazole-containing aromatase in-
hibitors are more selective
against inhibiting aromatase,
Compd
R1
R2
R3
R4
Aromatase IC50 [nm]
2a
3a
4a
H
F
Cl
Br
H
H
F
–
F2HC
–
H
H
H
H
F
–
–
H
H
H
H
F
F
F
–
H
–
Cl
Cl
Br
H
H
–
H
H
H
H
H
F
H
–
H
–
H
Cl
H
H
F
H
H
H
H
H
H
H
–
H
–
H
H
H
–
23
2.9
2.5
1.1
3.9ꢁ0.6
1.3ꢁ0.7
6.7ꢁ1.6
0.14ꢁ0.03
1.5ꢁ0.3
297ꢁ25
3ꢁ0.5
5a
11 c
12b
13c
14h
15g
16d
17c
18c
19d
20e
21e
22e
25d
whereas
imidazole-containing
compounds show a wider inhibi-
tory profile against other cyto-
chrome P450 enzymes in addi-
tion to aromatase.
2.3ꢁ0.2
1.1ꢁ0.2
3993ꢁ12
2500ꢁ500
5500ꢁ500
0.028ꢁ0.004
2) Parent phenols
–
–
–
–
–
We reason that the parent phe-
nols of DASIs can act as AIs in
their own right because they
possess the minimum pharma-
cophore for inhibiting aroma-
–
tase, that is, a haem-ligating moiety such as a triazole or an
imidazole. In vivo, at least until all the STS is inhibited, the
parent phenol is anticipated to be the immediate product re-
leased after irreversible inactivation of STS by an aryl sulfamate
according to the various mechanisms of action proposed by
our group.[19,46–48] In addition, the parent phenol may also be
released if the sulfamate group is hydrolytically cleaved in the
plasma due to the limited chemical stability observed for some
sulfamates (which increases as the phenolic pKa is lowered).
Therefore, the parent phenols of all new sulfamates studied in
this work were also assessed for their ability to inhibit aroma-
tase.
Relocation of a halogen atom from the ortho to the meta
position to the hydroxy group has little effect on aromatase in-
hibition, as shown by the similar activities observed for 3a
(IC50 =2.9 nm) vs. 11 c (IC50 =3.9 nm), 4a (IC50 =2.5 nm) vs. 17c
(IC50 =3 nm), and 5a (IC50 =1.1 nm) vs. 19d (IC50 =1.1 nm). In
contrast, sulfamates 11, 17, and 19 are significantly weaker AIs
than 3, 4, and 5 respectively.
While adding a second fluoro atom to the remaining meta
position of 11 c (IC50 =3.9 nm) to give the m,m’-difluorinated
compound 12b (IC50 =1.3 nm) improves aromatase inhibition
by about threefold, the m,m’-chlorinated compound 18c
(IC50 =2.3 nm) shows similar aromatase inhibitory activity to its
m-chlorinated counterpart 17c (IC50 =3 nm). These results con-
trast those of sulfamates 12 and 18, which are both significant-
ly better AIs than 11 and 17.
Previous SAR studies have shown that parent phenols are
generally more potent than their corresponding aryl sulfa-
mates as aromatase inhibitors. In this work, however, only 11 c
(m-F), 14h (m-F, m’-F, ethylene linker), 15g (o-F2HC), 16d (-CF2-
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Similar to their sulfamates, the
o,m-difluorinated
compound
13c (IC50 =6.7 nm) is a weaker AI
than its m,m’-difluorinated coun-
terpart 12b (IC50 =1.3 nm). This
result supports the previous ob-
servation that disubstitution of
fluorine atoms is more effective
for aromatase inhibition if they
are substituted at the m,m’-posi-
tion rather than at the o,m-posi-
tion on the sulfamate-bearing
ring.
Replacing
the
methylene
linker of 12b (IC50 =1.3 nm) with
an ethylene linker improves the
aromatase inhibitory activity of
the resulting compound 14h
(IC50 =0.14 nm) by nearly tenfold.
This observation is not unprece-
dented, as a similar finding was
observed when the methylene
linkers of 2a–5a were replaced
with an ethylene linker.[24]
Figure 4. Generalisation of aromatase and STS inhibition exhibited by sulfamates 2–5, 11–22, and 25. Aromatase
inhibition: weak (IC50 ꢂ100 nm), moderate (10–100 nm), good (1–10 nm), potent (<1 nm); STS inhibition: weak
(IC50 >1000 nm), moderate (100–1000 nm), good (10–100 nm), potent (<10 nm); X=OSO2NH2; AI: aromatase in-
hibitor; STSI: STS inhibitor.
Replacing the ortho-fluorine
atom of 3a (IC50 =2.9 nm) with
a
difluoromethyl group only
leads to a moderate increase in potency against aromatase in
the resulting compound 15g (IC50 =1.52 nm). In contrast, di-
fluorination of the methylene linker of 2a (IC50 =23 nm) is
clearly detrimental to aromatase inhibition, as shown by the
~13-fold decrease in aromatase inhibitory observed for 16d
(IC50 =297 nm).
an ethylene linker or replaced with a difluoromethylene group,
where a large decrease in potency is observed. There is
a higher degree of variation in the aromatase inhibitory activi-
ties observed for the sulfamates, although the most detrimen-
tal modifications are replacement of the methylene linker with
an ethylene linker, and replacement of the para-cyanophenyl
ring with a phenyl, 3,5-difluorophenyl, or 2,2-difluorobenzo[d]-
[1,3]dioxol-5-yl ring. The most potent DASI discovered in this
work is the imidazole derivative 25, with IC50 values against ar-
omatase and STS in JEG-3 cells similar to those of letrozole
and 1 (STX64, Figure 1), respectively, obtained from the same
assay. The exceptionally potent aromatase inhibition observed
for 25 can be attributed to a stronger ligation of its imidazole
sp2 nitrogen atom to the iron of the haem group than the
equivalent in a triazole. Docking of 11 and 25 into the crystal
structure of human aromatase shows the two compounds
share a similar docking pose. Similarly, docking of the two
compounds into the crystal structure of human STS reveals
that 11 and 25 share a similar binding mode in the active site.
The parent phenols of the sulfamates are good to potent
AIs, although replacing the methylene linker with a difluoro-
methylene group as well as replacing the para-cyanophenyl
ring with a phenyl, 3,5-difluorophenyl, or 2,2-difluorobenzo[d]-
[1,3]dioxol-5-yl ring significantly decreases the aromatase in-
hibitory activities of the resulting derivatives. As expected, the
most potent AI is the imidazole derivative 25d. The SAR for
the phenols is generalised in Figure 5.
Like their sulfamate counterparts, the replacement of the
para-cyanophenyl ring of 2a with a phenyl, 3,5-difluorophenyl,
or 2,2-difluorobenzo[d][1,3]dioxol-5-yl ring is detrimental to ar-
omatase inhibition. The phenols 20e, 21e, and 22e have IC50
values two orders of magnitude higher than that of 2a.
The most potent in vitro AI in this work is the imidazole de-
rivative 25d (IC50 =0.028 nm) which is about sevenfold more
potent than its corresponding sulfamate 25 (IC50 =0.2 nm) and
three orders of magnitude more potent than the triazole coun-
terpart 11. In addition, the IC50 value of 25d against aromatase
in JEG-3 cells is an order of magnitude higher than that of le-
trozole (IC50 =0.89 nm) obtained from the same intact cell
assay. However, it is yet to be demonstrated whether this ex-
ceptionally high in vitro potency of 25d can be reproduced
in vivo when the efficacy of a drug is affected by various phar-
macokinetic parameters.
Conclusions
Modifications made to first-generation DASIs 2–5 produce
mixed results. The SAR for the sulfamates is generalised in
Figure 4. For STS inhibition, all derivatives show similar STS in-
hibitory activities unless the para-cyanophenyl ring is replaced
with a phenyl ring, and the methylene linker is elongated to
The present work further demonstrates the ability of this
structural class of compounds to act as DASIs. Although there
is no general breakthrough in designing compounds that ex-
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tance constraint of 2.3 ꢂ was applied between the ligating nitro-
gen atom of the triazole or imidazole ring and the haem iron
atom.
For sulfatase the sulfate group was removed from residue formyl-
glycine sulfate 75 (FGS75) to leave a gem-diol form of formylgly-
cine residue. The centroid of the docked ligand was required to be
within 5 ꢂ of the calcium ion in the substrate binding site. No con-
straints were applied during the docking.
General methods for synthesis: All chemicals were purchased
from either Aldrich Chemical Co. (Gillingham, UK) or Alfa Aesar
(Heysham, UK). All organic solvents of analytical reagent grade
were supplied by Fisher Scientific (Loughborough, UK). Anhydrous
N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA) and
tetrahydrofuran (THF) were purchased from Aldrich. Sulfamoyl
chloride was prepared by an adaptation of the method of Appel
and Berger[51] and was stored as a solution under N2 in toluene as
described by Woo et al.[46]
Thin-layer chromatography (TLC) was performed on pre-coated
aluminium plates (Merck, silica gel 60 F254). Product spots were vi-
sualised either by UV irradiation at l 254 nm or by staining with
either an alkaline solution of KMnO4 or 5% w/v dodecamolybdo-
phosphoric acid in EtOH, followed by heating. Flash column chro-
matography was performed on silica gel (Davisil silica 60A) or pre-
packed columns (Isolute), and gradient elution (solvents indicated
in text) on either the Flashmaster II system (Biotage) or on a Tele-
dyne ISCO CombiFlash Rf Automated Flash Chromatography
Figure 5. Generalisation of aromatase inhibition exhibited by phenols 2a–
5a, 11 c, 12b, 13c, 14h, 15g, 17c, 18c, 19d, 20e, 21e, 22e, and 25d. Aro-
matase inhibition: weak (IC50 ꢂ100 nm), moderate (10–100 nm), good (1–
10 nm), potent (<1 nm); AI: aromatase inhibitor
1
System with RediSep Rf disposable flash columns. H and 13C NMR
hibit more potent dual inhibition in vitro, interestingly, if the
triazole group is replaced by an imidazole as the haem-ligating
species, significant activity enhancement is observed both for
aromatase and dual aromatase–sulfatase inhibition. The syn-
thesis of more imidazole-containing DASIs is therefore warrant-
ed, although to establish real potential for drug design, the
in vivo activities of these compounds need to be assessed in
parallel in order to evaluate their metabolic stability as well as
selectivity towards aromatase inhibition.
spectra were recorded with either a Jeol Delta 270 MHz or a Varian
Mercury VX 400 MHz spectrometer. Chemical shifts (d) are reported
in parts per million (ppm) relative to tetramethylsilane (TMS) as an
internal standard. Coupling constants (J) are recorded to the near-
est 0.1 Hz. Mass spectra were recorded at the Mass Spectrometry
Service Centre, University of Bath (UK). FAB mass spectra were car-
ried out with m-nitrobenzyl alcohol as the matrix. Elemental analy-
ses were performed by the Microanalysis Service, University of
Bath. Melting points were determined with either a Stuart Scientific
SMP3 or a Stanford Research Systems Optimelt MPA100 and are
uncorrected.
Experimental Section
LC–MS and HPLC: LC–MS was performed using a Waters 2790 in-
strument with a ZQ MicroMass spectrometer and PDA detector.
The ionisation technique used was either APCI or ES (as indicated
in the text). A Waters Symmetry C18 (packing: 3.5 mm) 4.6ꢃ100 mm
column with gradient elution 5:95 CH3CN/H2O (flow rate:
0.5 mLminꢀ1) to 95:5 CH3CN/H2O (flow rate: 1 mLminꢀ1) over
10 min were used. HPLC was undertaken using a Waters 717 ma-
chine with Autosampler and PDA detector. The column used was
a Waters Symmetry C18 (packing: 3.5 mm) 4.6ꢃ150 mm with an iso-
cratic mobile phase consisting of MeOH/H2O (as indicated) at
In vitro aromatase and sulfatase assays: Biological activities were
performed essentially as described previously.[23] The extent of in vi-
tro inhibition of aromatase and sulfatase activities was assessed
using intact monolayers of JEG-3 human choriocarcinoma cells,
which were chosen because these cells constitutively express both
enzymes maximally. Aromatase activity was measured with [1b-
3H]androstenedione (30 Cimmolꢀ1, PerkinElmer Life Sciences, MA,
USA) over a 1 h period. Sulfatase activity was measured using [6,7-
3H]E1S (50 Cimmolꢀ1, PerkinElmer) over a 1 h period.
a flow rate of 1.4 mLminꢀ1
.
Molecular modelling: The 3EQM crystal structure of aromatase[42,43]
and the 1P49 crystal structure of sulfatase[44] were used for docking
studies. They were passed through the Protein Preparation Wizard
of the Schrçdinger software platform. GOLD[49] was used to dock
the ligands into both substrate binding sites. [NB: Four new crystal
structures of aromatase have recently been released:[50] 3S79 (with
androstenedione) is effectively identical to the 3EQM structure,
3S7S (with exemestane), and 4GL5 and 4GL7, which both have O-
linked alkyl chains attached to the 6-position of the steroid ring.]
General method A—hydrogenation: Pd/C was added to a solution
of the substrate in the solvents indicated. The solution was stirred
under an atmosphere of H2 (provided by addition from a balloon)
overnight. The excess H2 was removed, and the reaction mixture
was filtered through Celite washing with THF and MeOH, then the
solvent was removed in vacuo.
General method B—sulfamoylation: A solution of sulfamoyl chlo-
ride (H2NSO2Cl) in toluene was concentrated in vacuo at 308C to
furnish a yellow oil which solidified upon cooling in an ice bath.
DMA and the substrate were subsequently added, and the mixture
was allowed to warm to room temperature and stirred overnight.
For aromatase the binding site was centred on the crystal structure
ligand (androstenedione) and required the centroid of the docked
ligand to be within 5 ꢂ of the androstenedione centroid. A dis-
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The reaction mixture was poured onto H2O and extracted three
times with EtOAc. The organic layers were combined, washed four
times with H2O, and then with brine, dried (MgSO4), and the sol-
vent was removed in vacuo.
(2ꢃCH), 143.3 (2ꢃCH), 150.9 (C, d), 151.1 (C), 159.9 ppm (C, d);
19F NMR (376 MHz, [D6]DMSO): d=ꢀ114.1 ppm t; LC–MS (ES+):
tR =1.14 min, m/z (%): 389.0 (100) [M+H]+; HRMS (ES+): m/z [M+
H]+ calcd for C16H14FN6O3S: 389.0827, found: 389.0819; HPLC: tR =
1.26 min (>99%), (CH3CN/H2O, 90:10).
Methyl 2-fluoro-4-hydroxybenzoate (11a): A solution of 2-fluoro-
4-hydroxybenzoic acid (5.30 g, 34.0 mmol) and conc. HCl (30 drops)
in MeOH (100 mL) was heated at reflux for 12 h. The mixture was
allowed to cool and was neutralised with sat. aq. NaHCO3. The sol-
vent was removed in vacuo, and the residue was dissolved in
EtOAc (100 mL) and washed with H2O (100 mL), sat. aq. NaHCO3
(100 mL), and brine (100 mL), then dried (MgSO4), and the solvent
was removed in vacuo. The title compound was obtained as
3,5-Difluoro-4-(hydroxymethyl)phenol (12a): 2,6-Difluoro-4-hy-
droxybenzoic acid (0.50 g, 2.87 mmol) was cautiously added to
a suspension of LiAlH4 (0.55 g, 14.5 mmol) in THF (20 mL). The re-
sulting mixture was stirred at reflux for 24 h. After cooling to room
temperature, the reaction was quenched by the cautious addition
of EtOAc (10 mL) and then H2O (10 mL). A further portion of EtOAc
(50 mL) was added and the layers were separated. The aqueous
layer was extracted with EtOAc (50 mL) and the combined organic
layers were washed with 3m aq. HCl (2ꢃ50 mL), then dried
(MgSO4) and the solvent was removed in vacuo to give title com-
1
a white powder (4.52 g, 78%): mp: 154–1568C; H NMR (270 MHz,
[D6]DMSO): d=3.79 (3H, s, CH3), 6.63 (1H, dd, J=13.2, 2.2 Hz, ArH),
6.70 (1H, dd, J=8.5, 2.2 Hz, ArH), 7.77 (1H, t, J=8.8 Hz, ArH),
10.83 ppm (1H, s, OH).
pound as
a
white solid (0.40 g, 87%): 1H NMR (270 MHz,
[D6]DMSO): d=4.36 (2H, d, J=5.4 Hz, CH2), 5.03 (1H, d, J=5.4 Hz,
OH), 6.39–6.50 (2H, m, ArH), 10.43 ppm (1H, s, OH); LC–MS (ESꢀ):
tR =0.90 min, m/z (%): 158.9 (100) [MꢀH]ꢀ, 140.9 (60).
3-Fluoro-4-(hydroxymethyl)phenol (11b):
A solution of 11 a
(1.50 g, 8.82 mmol) in THF (10 mL) was added to a suspension of
LiAlH4 (0.84 g, 22.1 mmol) in THF (35 mL). After 45 min the reaction
was quenched by cautious addition of EtOAc (15 mL), H2O (15 mL),
and 3m HCl (15 mL). The product was extracted with EtOAc (2ꢃ
75 mL), and the combined organic layers were washed with sat.
aq. NaHCO3 (100 mL), dried (MgSO4), and the solvent was removed
in vacuo to give the title compound as a cream solid (0.95 g, 76%):
4-[(2,6-Difluoro-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl)amino]-
benzonitrile (12b): A solution of 12a (0.37 g, 2.31 mmol) in SOCl2
(5 mL) was stirred for 2 h, then the SOCl2 was removed in vacuo.
The residue was dissolved in DMF (7 mL) and 10 (0.45 g,
2.43 mmol) and K2CO3 (1.60 g, 11.6 mmol) were added and the re-
action mixture was stirred overnight. The mixture was poured onto
H2O (30 mL) and extracted with EtOAc (2ꢃ30 mL). The combined
organics were washed with H2O (4ꢃ30 mL) and brine (30 mL), then
dried (MgSO4) and the solvent was removed in vacuo. The crude
product was purified using Flashmaster II (CH2Cl2/acetone) to give
the title compound as a white solid (0.23 g, 30%); mp: 2178C
(dec.); 1H NMR (270 MHz, [D6]DMSO): d=4.99 (2H, s, CH2), 6.38–
6.48 (2H, m, ArH), 6.79 (2H, m, AA’BB’, ArH), 7.77 (2H, m, AA’BB’,
ArH), 8.73 (2H, s, 2ꢃCHN), 10.49 ppm (1H, s, OH); 13C NMR
(100 MHz, [D6]DMSO): d=44.6 (CH2), 99.4 (2ꢃCH, d), 100.2 (C, t),
102.9 (C), 113.6 (2ꢃCH), 119.1 (C), 134.0 (2ꢃCH), 143.4 (2ꢃCH),
151.0 (C), 160.0 (C, t), 161.8 ppm (2ꢃC, dd); 19F NMR (376 MHz,
[D6]DMSO): d=ꢀ114.7 ppm d; LC–MS (ES+): tR =3.11 min, m/z (%):
328.2 (100) [M+H]+, 259.1 (40); HRMS (ES+): m/z [M+H]+ calcd
for C16H12F2N5O: 328.1004, found: 328.1008; HPLC: tR =1.43 min
(98.3%), (CH3CN/H2O, 90:10).
1
mp: 111–1138C; H NMR (270 MHz, [D6]DMSO): d=4.40 (2H, d, J=
5.2 Hz, CH2), 5.02 (1H, t, J=5.2 Hz, OH), 6.51 (1H, dd, J=11.9,
2.5 Hz, ArH), 6.58 (1H, dd, J=8.3, 2.5 Hz, ArH), 7.21 (1H, t, J=
8.8 Hz, ArH), 9.76 ppm (1H, brs, OH).
4-[(2-Fluoro-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl)amino]benzo-
nitrile (11c): A solution of 11 b (0.82 g, 4.43 mmol) in SOCl2 (5 mL)
was stirred for 2 h, then the SOCl2 was removed in vacuo. The resi-
due was dissolved in DMF (8 mL), and 10 (0.60 g, 4.23 mmol) and
K2CO3 (2.92 g, 21.2 mmol) were added, and the reaction mixture
was stirred for 48 h. The mixture was poured onto H2O (30 mL),
and the product was extracted with EtOAc (2ꢃ30 mL). The com-
bined organic layers were washed with H2O (4ꢃ30 mL) and brine
(30 mL), then dried (MgSO4), and the solvent was removed in va-
cuo. The crude product was purified using the CombiFlash system
(CHCl3/acetone) to give the title compound as a white powder
1
(0.26 g, 20%): mp: 217–2198C; H NMR (270 MHz, [D6]DMSO): d=
4.96 (2H, s, CH2), 6.49–6.55 (2H, m, ArH), 6.76 (2H, AA’BB’, ArH),
7.04 (1H, d, J=8.2 Hz, ArH), 7.76 (2H, AA’BB’, ArH), 8.71 (2H, s, 2ꢃ
CHN), 10.09 ppm (1H, s, OH); 13C NMR (100 MHz, [D6]DMSO): d=
50.7 (CH2), 102.5 (C), 102.7 (CH), 111.0 (C, d), 111.7 (CH, d), 113.6
(2ꢃCH), 119.1 (C), 132.1 (CH, d), 133.9 (2ꢃCH), 143.4 (2ꢃCH), 151.3
(C), 159.3 (C, d), 161.3 ppm (C, d); 19F NMR (376 MHz, [D6]DMSO):
d=ꢀ116.1 ppm t; LC–MS (ES+): tR =1.37 min, m/z (%): 310.0 (100)
[M+H]+; HRMS (ES+): m/z [M+H]+ calcd for C16H13FN5O:
310.1099, found: 310.1099; HPLC: tR =1.29 min (>99%), (CH3CN/
H2O, 90:10).
4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-3,5-di-
fluorophenyl sulfamate (12): As general method B using ClSO2NH2
(0.6m, 5.0 mL), DMA (3 mL) and 12b (0.15 g, 0.46 mmol). The crude
product was purified using Flashmaster II (CH2Cl2/acetone) to give
the title compound (0.14 g, 75%) as a white amorphous solid;
1H NMR (270 MHz, [D6]DMSO): d=5.16 (2H, s, CH2), 6.81 (2H, m,
AA’BB’, ArH), 7.09 (2H, m, ArH), 7.80 (2H, AA’BB’, ArH), 8.33 (2H, s,
NH2), 8.80 ppm (2H, s, 2ꢃCHN); 13C NMR (600 MHz, [D6]DMSO): d=
44.8 (CH2), 103.2 (C), 106.3 (2ꢃCH, d), 108.8 (C, t), 113.7 (2ꢃCH),
119.0 (C), 134.1 (2ꢃCH), 143.4 (2ꢃCH), 150.9 (C), 151.4 (C, d),
161.2 ppm (2ꢃC, m); 19F NMR (376 MHz, [D6]DMSO): d=
ꢀ112.3 ppm s; LC–MS (ES+): tR =1.06 min, m/z (%): 405.0 (100)
[MꢀH]ꢀ; HRMS (ES+): m/z [M+H]+ calcd for C16H13F2N6O3S:
407.0732, found: 407.0726; HPLC: tR =1.42 min (>99%), (CH3CN/
H2O, 90:10).
4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-3-fluoro-
phenyl sulfamate (11): As general method B using ClSO2NH2
(0.63m, 4.4 mL), DMA (2.5 mL) and 11 c (0.17 g, 0.55 mmol). The
crude product was purified using the CombiFlash system (CHCl3/
acetone) to give the title compound as a white amorphous solid
1
(0.17 g, 80%): H NMR (270 MHz, [D6]DMSO): d=5.15 (2H, s, CH2),
Methyl 2,3-difluoro-4-hydroxybenzoate (13a): SOCl2 (0.63 g,
4.57 mmol) was added to a solution of 2,3-difluoro-4-hydroxyben-
zoic acid (0.20 g, 1.15 mmol) in MeOH (10 mL) and the mixture was
heated at reflux for 24 h. After cooling to room temperature the
solvent was removed in vacuo to give the title compound as
a beige powder in a quantitative yield: mp: 138–1408C; 1H NMR
6.75 (2H, AA’BB’, ArH), 7.08 (1H, dd, J=8.6, 2.2 Hz, ArH), 7.17 (1H,
dd, J=10.7, 2.2 Hz, ArH), 7.46 (1H, t, J=8.6 Hz, ArH), 7.77 (2H,
AA’BB’, ArH), 8.17 (2H, s, NH2), 8.83 ppm (2H, s, 2ꢃCHN); 13C NMR
(100 MHz, [D6]DMSO): d=50.9 (CH2), 103.0 (C), 109.9 (CH, d), 113.6
(2ꢃCH), 118.3 (CH), 118.6 (C, d), 120.0 (C, d), 131.6 (CH, d), 134.0
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemMedChem 2013, 8, 779 – 799 789

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(270 MHz, [D6]DMSO): d=3.81 (3H, s, CH3), 6.87 (1H, td, J=9.1,
2.2 Hz, ArH), 7.57 (1H, td, J=9.1, 2.2 Hz, ArH), 11.41 ppm (1H, brs,
OH); LC–MS (ESꢀ): tR =0.85 min, m/z (%): 186.7 (100) [MꢀH]ꢀ.
dried (MgSO4) and solvent was removed in vacuo to give the title
compound as a tan-coloured solid (4.50 g, 88%): mp: 1578C (dec.);
1H NMR (270 MHz, [D6]DMSO): d=3.78 (3H, s, CH3), 4.72 (1H, s, CH),
6.70–6.79 ppm (2H, m, ArH).
2,3-Difluoro-4-(hydroxymethyl)phenol (13b): A solution of 13a
(0.17 g, 0.90 mmol) in THF (2 mL) was added to a suspension of
LiAlH4 (0.10 g, 2.63 mmol) in THF (5 mL). After 45 min the reaction
was quenched by the cautious addition of EtOAc (3 mL), H2O
(3 mL) and 3m HCl (3 mL). The product was extracted with EtOAc
(2ꢃ15 mL) and the combined organics were washed with sat. aq.
NaHCO3 (20 mL) dried (MgSO4) and the solvent was removed in va-
cuo to give the title compound as an off-white solid (0.14 g, 94%):
mp: 1148C (dec.); 1H NMR (270 MHz, [D6]DMSO): d=4.42 (2H, d,
J=5.3 Hz, CH2), 5.17 (1H, t, J=5.3 Hz, OH), 6.74 (1H, td, J=8.3,
2.2 Hz, ArH), 7.00 (1H, td, J=8.3, 2.2 Hz, ArH), 10.26 ppm (1H, brs,
OH); 13C NMR (100 MHz, [D6]DMSO): d=56.5 (CH2), 112.4 (CH),
120.8 (C), 123.3 (CH), 139.5 (C), 145.5 (C), 148.6 ppm (C); LC–MS
(ESꢀ): tR =0.82 min, m/z (%): 158.8 (100) [MꢀH]ꢀ; HRMS (ES+): m/z
[M+Na]+ calcd for C7H6F2NaO2:183.0228, found: 183.0220.
2-(2,6-Difluoro-4-methoxyphenyl)acetic acid (14b): 14a (4.49 g,
18.3 mmol) was heated at 1608C until melting was complete and
fizzing had ceased. Following cooling, the product was recrystal-
lised from petroleum ether (PE)/EtOAC to give the title compound
1
as a white crystalline solid (3.43 g, 93%): mp: 137–1398C; H NMR
(270 MHz, [D6]DMSO): d=3.52 (2H, s, CH2), 3.77 (3H, s, CH3), 6.68–
6.79 ppm (2H, m, ArH); HRMS (ES+): m/z [M+H]+ calcd for
C9H8F2O3: 203.0514, found: 203.0508.
Methyl 2-(2,6-difluoro-4-methoxyphenyl)acetate (14c): A solution
of 14b (3.37 g, 16.7 mmol) in MeOH (70 mL) containing conc. HCl
(15 drops) was heated at reflux overnight. The mixture was allowed
to cool and was neutralised with sat. aq. NaHCO3. The solvent was
removed in vacuo and the residue was dissolved in EtOAc (100 mL)
and washed with H2O (100 mL), sat. aq. NaHCO3 (100 mL) and
brine (100 mL) then dried (MgSO4) and the solvent was removed in
vacuo. The title compound was obtained as a pale-yellow oil
4-[(2,3-Difluoro-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl)amino]-
benzonitrile (13c): A solution of 13b (0.24 g, 1.50 mmol) in SOCl2
(5 mL) was stirred for 2 h, then the SOCl2 was removed in vacuo.
The residue was dissolved in DMF (5 mL) and 10 (0.29 g,
1.58 mmol) and K2CO3 (1.04 g, 7.53 mmol) were added and reaction
mixture stirred for 72 h. The mixture was poured onto H2O (50 mL)
and extracted with EtOAc (2ꢃ30 mL). The combined organics were
washed with H2O (4ꢃ30 mL) and brine (30 mL), then dried
(MgSO4), and the solvent was removed in vacuo. The crude prod-
uct was purified using Flashmaster II (EtOAc/hexane) and (CH2Cl2/
acetone) to give the title compound as a white solid (0.15 g, 15%):
mp: 2258C (dec.); 1H NMR (270 MHz, [D6]DMSO): d=5.02 (2H, s,
CH2), 6.6.3–6.89 (4H, m, ArH), 7.77 (2H, m, AA’BB’, ArH), 8.76 (2H, s,
2ꢃCHN), 10.58 ppm (1H, s, OH); 13C NMR (100 MHz, [D6]DMSO):
d=50.7 (CH2), 102.9 (C), 112.7 (CH), 112.8 (2ꢃCH), 119.0 (C), 125.2
(C, CH), 133.9 (2ꢃCH), 139.5 (C, dd), 143.4 (2ꢃCH), 147.1 (2ꢃC, m),
149.5 (C, dd), 151.1 ppm (C); 19F NMR (376 MHz, [D6]DMSO): d=
ꢀ141.4 (dd), ꢀ161.1 ppm (dd); LC–MS (ES+): tR =0.76 min, m/z
(%): 350.0 (100) [M+Na]+, 328 (20), 258.9 (15); HRMS (ES+): m/z
[M+H]+ calcd for C16H12F2N5O: 328.1004, found: 328.0990; HPLC
tR =1.23 min (>99%), (CH3CN/H2O, 90:10).
1
(3.30 g, 92%); H NMR (270 MHz, [D6]DMSO): d=3.61 (2H, s, CH2),
3.69 (3H, s, CH3), 3.76 (3H, s, CH3), 6.40–6.49 ppm (2H, m, ArH);
19F NMR (376.4 MHz, [D6]DMSO): d=ꢀ114.4 ppm (d); LC–MS (ES+):
tR =1.69 min, m/z (%): 216.8 (100) [M]+; HRMS (ES+): m/z [M+H]+
calcd for C10H11F2O3: 217.0657, found: 217.0663.
Methyl 2-(2,6-difluoro-4-hydroxyphenyl)acetate (14d): BBr3 (1m
in CH2Cl2, 55 mL, 55 mmol) was added to a cooled (ꢀ788C) solu-
tion of 14c (2.87 g, 13.3 mmol) in CH2Cl2 (25 mL). The reaction mix-
ture was stirred at ꢀ788C for 10 min, then allowed to warm to
room temperature and stirred for 3.5 h. The reaction was
quenched with sat. aq. NaHCO3 and the product was extracted
with CH2Cl2 (2ꢃ150 mL). The combined organic layers were
washed with brine (150 mL), dried (MgSO4) and the solvent was re-
moved in vacuo. The crude product was purified using the Combi-
Flash system (PE/EtOAc) to give the title compound as a white
1
crystalline solid (2.07 g, 77%): mp: 75.5–77.58C; H NMR (270 MHz,
[D6]DMSO): d=3.58 (2H, s, CH2), 3.61 (3H, s, CH3), 6.41–6.51 (2H,
m, ArH), 10.34 ppm (1H, s, OH); 19F NMR (376.4 MHz, [D6]DMSO):
d=ꢀ115.4 ppm (d); LC–MS (ES+): tR =1.45 min, m/z (%): 202.8
(100) [M+H]+; HRMS (ES+): m/z [M+H]+ calcd for C9H9F2O3:
203.0514, found: 203.0511.
4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-2,3-di-
fluorophenyl sulfamate (13): As general method B using ClSO2NH2
(0.6m, 3.4 mL), DMA (3 mL) and 13c (0.11 g, 0.34 mmol). The crude
product was purified using Flashmaster II (CH2Cl2/acetone) to give
the title compound as an amorphous white solid (0.14 g, 95%);
1H NMR (270 MHz, [D6]DMSO): d=5.21 (2H, s, CH2), 6.75 (2H, m,
AA’BB’, ArH), 7.18–7.31 (2H, m, ArH), 7.77 (2H, AA’BB’, ArH), 8.41
(2H, s, NH2), 8.88 ppm (2H, s, 2ꢃCHN); 13C NMR (100 MHz,
[D6]DMSO): d=55.9 (CH2), 103.1 (C), 113.6 (2ꢃCH), 119.0 (CH), 119.7
(C), 122.5 (C, d), 124.7 (CH), 134.1 (2ꢃCH), 138.5 (C, m), 143.2 (C,
dd), 143.4 (2ꢃCH), 148.9 (C, dd), 150.9 ppm (C); 19F NMR (376 MHz,
[D6]DMSO): d=ꢀ151.5 (dd), ꢀ138.6 ppm (dd); LC–MS (ES+): tR =
0.87 min, m/z (%): 407.0 (100) [M+H]+; HRMS (ES+): m/z [M+H]+
calcd for C16H13F2N6O3S: 407.0732, found: 407.0722; HPLC: tR =
1.34 min (>99%), (CH3CN/H2O, 90:10).
Methyl
2-[2,6-difluoro-4-(triisopropylsilyloxy)phenyl]acetate
(14e): Imidazole (1.43 g, 21.0 mmol) and triisopropylsilyl chloride
(TIPSCl, 2.24 g, 11.6 mmol) were sequentially added to a pale-
yellow solution of 14d (2.13 g, 10.5 mmol) in DMF (10 mL). The re-
action mixture was stirred overnight, then poured onto H2O
(40 mL) and extracted with EtOAc (3ꢃ50 mL). The combined or-
ganics were washed with H2O (3ꢃ100 mL) and brine (100 mL),
then dried (MgSO4) and the solvent was removed in vacuo. The
crude product was purified using the CombiFlash system (PE/
EtOAc) to give the title compound as a colourless oil (3.43 g, 91%);
1H NMR (270 MHz, CDCl3): d=1.04–1.32 (21H, m, 6ꢃCH3, 3ꢃCH),
3.60 (2H, s, CH2), 3.69 (3H, s, CH3), 6.36–6.48 ppm (2H, m, ArH);
13C NMR (100 MHz, [D6]DMSO): d=12.5 (3ꢃCH), 17.8 (6ꢃCH3), 27.4
(CH2), 52.2 (CH3), 103.3 (C, t), 103.4 (2ꢃCH, dd), 156.7 (C, t), 161.6
(2ꢃC, dd), 170.6 ppm (C); 19F NMR (376 MHz, [D6]DMSO): d=
ꢀ117.9 ppm (d).
2-(2,6-Difluoro-4-methoxyphenyl)malonic acid (14a): 3m aq.
NaOH (80 mL) added to a solution of diethyl 2-(2,6-difluoro-4-me-
thoxyphenyl)malonate (synthesised according to a patented proce-
dure;[34] 6.30 g, 20.85 mmol) in Et2O (5 mL). The reaction mixture
was heated at reflux until all the solid had dissolved. After cooling,
the mixture was acidified with 3m aq. HCl and the product was ex-
tracted with EtOAc (2ꢃ100 mL). The combined organic layers were
2-[2,6-Difluoro-4-(triisopropylsilyloxy)phenyl]ethanol (14 f): A so-
lution of 14e (2.98 g, 8.30 mmol) in THF (15 mL) was added to
a cooled (08C) suspension of LiAlH4 (0.79 g, 20.8 mol) in THF
(50 mL). After stirring for 15 min, the reaction was quenched by
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemMedChem 2013, 8, 779 – 799 790

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the sequential addition of EtOAc (25 mL), H2O (25 mL) and 3m HCl
(25 mL). The product was extracted with EtOAc (2ꢃ75 mL) and the
combined organic layers were washed with sat. aq. NaHCO3 (2ꢃ
100 mL) dried (MgSO4) and the solvent was removed in vacuo. The
crude product was purified using the CombiFlash system (EtOAc/
PE) to give the title compound as a colourless oil (1.70 g, 62%);
1H NMR (270 MHz, CDCl3): d=1.02–1.31 (21H, m, 6ꢃCH3, 3ꢃCH),
1.61 (1H, s, OH), 2.85 (2H, t, J=6.9 Hz, CH2), 3.76 (2H, t, J=6.9 Hz,
CH2), 6.34–6.48 ppm (2H, m, ArH); 19F NMR (376 MHz, [D6]DMSO):
d=ꢀ116.0 ppm (d); LC–MS (ES+): tR =2.23 min, m/z (%): 353.4
(100) [M+Na]+, 331.3 (80) [M+1]+; HRMS (ES+): m/z [M+H]+
calcd for C17H29F2O2Si: 331.1899, found: 331.1887.
3-Formyl-4-hydroxybenzoic acid methyl ester (15a): This com-
pound was prepared according to the method described by Hof-
sløkken and Skattebol;[35] yield=38%.
3-Difluoromethyl-4-hydroxybenzoic acid methyl ester (15b): A
solution of 15a (1.40 g, 7.78 mmol) in CH2Cl2 (20 mL) was added to
a solution of Deoxo-Fluorꢁ (2.92 g, 13.2 mmol) in CH2Cl2 then EtOH
(0.072 g, 89 mL, 1.56 mol) was added and the resultant was stirred
for 6 h. The reaction mixture was quenched by the cautious addi-
tion of sat. aq. NaHCO3 then CH2Cl2 (75 mL was added). The layers
were separated and the organic washed with H2O (75 mL) and
brine (75 mL), then dried (MgSO4) and the solvent was removed in
vacuo. The crude product was purified using Flashmaster II (EtOAc/
hexane) to give the title compound as a white solid (1.18 g, 75%):
mp: 141–1428C; 1H NMR (270 MHz, [D6]DMSO): d=3.91 (3H, s,
CH3), 6.56 (1H, brs, OH), 6.88 (1H, t, J=55.2 Hz, CHF2), 6.93 (1H, d,
J=8.6 Hz, ArH), 8.02 (1H, d, J=8.6 Hz, ArH), 8.16 ppm (1H, s, ArH);
13C NMR (100 MHz, [D6]DMSO): d=52.4 (CH3), 112.4 (CH, t), 116.7
(CH), 120.8 (C), 120.9 (C, t), 128.1 (CH, t), 134.0 (CH), 160.4 (C, t),
165.9 ppm (C); LC–MS (APCIꢀ): tR =2.74 min, m/z (%): 200.9 (100)
[MꢀH]ꢀ, 180.9 (75), 152.8 (50), 138.8 (20); HRMS (ES+): m/z [M+
H]+ calcd for C9H9F2O3: 203.0514, found: 203.0514.
[4-(2-Bromoethyl)-3,5-difluorophenoxy]triisopropylsilane (14g):
Triphenylphosphine (PPh3, 1.11 g, 4.24 mmol) was added to
a cooled (08C) solution of CBr4 (0.92 g, 2.77 mmol) in CH2Cl2
(15 mL). After stirring for 15 min, a solution of 14 f (0.70 g,
2.12 mmol) in CH2Cl2 (5 mL) was added and the reaction mixture
was stirred for 1 h, then allowed to warm to room temperature
and stirred for 2 h. The solvent was removed in vacuo and the resi-
due was purified using the CombiFlash system (EtOAc/PE) to give
the title compound as a colourless oil (0.56 g, 67%); 1H NMR
(270 MHz, CDCl3): d=1.05–1.32 (21H, m, 6ꢃCH3, 3ꢃCH), 3.13 (2H,
t, J=7.7 Hz, CH2), 3.48 (2H, t, J=7.7 Hz, CH2), 6.34–6.45 ppm (2H,
m, ArH).
3-Difluoromethyl-4-triisopropylsilanyloxybenzoic acid methyl
ester (15c): Imidazole (0.79 g, 11.6 mmol) and TIPSCl (1.24 g,
6.42 mmol) were sequentially added to a solution of 15b (1.18 g,
5.84 mmol) in DMF (15 mL). The reaction mixture was stirred over-
night, then poured onto H2O (50 mL) and extracted with EtOAc
(3ꢃ50 mL). The combined organics were washed with H2O (3ꢃ
75 mL) and brine (75 mL), then dried (MgSO4) and the solvent was
removed in vacuo. The crude product was purified using Flashmas-
ter II (EtOAc/hexane) to give the title compound as a colourless oil
4-[(2,6-Difluoro-4-hydroxyphenethyl)(4H-1,2,4-triazol-4-yl)ami-
no]benzonitrile (14h): NaH (60% dispersion in mineral oil, 0.057 g,
1.42 mmol) was added to a solution of 14g (0.24 g, 1.30 mmol) in
DMF (7 mL). After stirring for 30 min a solution of 10 (0.56 g,
1.42 mmol) in DMF (3 mL) was added and stirring was continued
for 48 h. TBAF (1m in THF, 1.75 mL) was added and after 30 min
the reaction mixture was poured onto H2O (15 mL) and acidified
with 3m aq. AcOH. The product was extracted with EtOAc (3ꢃ
20 mL) and the combined organics were washed with H2O (4ꢃ
50 mL) and brine (50 mL) then dried (MgSO4) and the solvent was
removed in vacuo. The crude product was purified using the Com-
biFlash system (CHCl3/acetone) to give the title compound as
a white solid (0.18 g, 41%): mp: 2758C (dec.); 1H NMR (270 MHz,
[D6]DMSO): d=2.79 (2H, t, J=7.5 Hz, CH2), 3.96 (2H, t, J=7.5 Hz,
CH2), 6.41–6.50 (2H, m, ArH), 6.58 (2H, AA’BB’, ArH), 7.73 (2H,
AA’BB’, ArH), 8.87 (2H, s, 2ꢃCHN), 10.32 ppm (1H, s, OH); 13C NMR
(100 MHz, [D6]DMSO): d=19.4 (CH2), 52.7 (CH2), 99.2 (2ꢃCH, d),
102.4 (C), 102.6 (C), 112.8 (2ꢃCH), 119.0 (C), 134.0 (2ꢃCH), 143.4
(2ꢃCH), 150.6 (C), 158.1 (C, t), 161.3 ppm (2ꢃC, dd); 19F NMR
(376 MHz, [D6]DMSO): d=ꢀ116.0 ppm (d); LC–MS (ES+): tR =
1.26 min, m/z (%): 342.2 (100) [M+H]+; HRMS (ES+): m/z [M+H]+
calcd for C17H14F2N5O: 342.1161, found: 342.1153; HPLC: tR =
1.31 min (98.5%), (CH3CN/H2O, 90:10).
1
(2.11g, 99%): H NMR (400 MHz, CDCl3): d=1.06–1.42 (21H, m, 3ꢃ
CH, 6ꢃCH3), 3.89 (3H, s, OCH3), 6.86 (1H, d, J=8.6 Hz, ArH), 6.91
(1H, t, J=55.0 Hz, CH2F), 8.00 (1H, d, J=8.6 Hz, ArH), 8.23 ppm
(1H, s, ArH); 13C NMR (100 MHz, [D6]DMSO): d=12.94 (3ꢃCH),
17.64 (6ꢃCH3), 52.1 (CH3), 111.4 (CH, t), 118.4 (CH), 122.9 (C), 124.7
(C, t), 128.7 (CH, t), 133.4 (CH), 158.2 (C, t), 166.2 ppm (C); LC–MS
(APCI): tR =1.75 min, m/z (%) 359.3 (100) [M+H]+; HRMS (ES+):
m/z [M+H]+ calcd for C18H29F2O3Si: 359.1849, found: 359.1846.
(3-Difluoromethyl-4-triisopropylsilanyloxyphenyl)methanol
(15d): LiBH4 (0.31 g, 14.1 mmol) and B(OMe)3 (0.058 g, 0.56 mmol)
were sequentially added to a solution of 15c (2.00 g, 5.58 mmol) in
Et2O (70 mL). The reaction mixture was stirred overnight and was
then diluted with Et2O (70 mL) and quenched by the cautious addi-
tion of H2O (70 mL). The layers were separated and the organic
layer was washed with brine (70 mL), then dried (MgSO4) and the
solvent was removed in vacuo. The crude product was purified
using the Flashmaster II system (EtOAc/hexane) to give the title
compound as a colourless oil (1.23 g, 67%): 1H NMR (300 MHz,
CDCl3): d=1.02–1.31 (21H, m, 3ꢃCH, 6ꢃCH3), 1.56 (1H, t, J=
5.1 Hz, OH), 4.57 (2H, d, J=5.1 Hz, CH2), 6.77 (1H, d, J=8.3 Hz,
ArH), 6.88 (1H, t, J=55.0 Hz, CH2F), 7.25 (1H, d, J=8.3 Hz, ArH),
7.46 ppm (1H, s, ArH); 13C NMR (68 MHz, CDCl3): d=13.0 (3ꢃCH),
18.0 (6ꢃCH3), 64.9 (CH2), 111.9 (CH, t), 118.6 (CH), 124.5 (C, t), 125.5
(CH, t), 130.7 (CH), 133.4 (C), 153.8 ppm (C, t); LRMS (FAB+): m/z
(%): 331.4 (10) [M]+, 313.1 (100); HRMS (ES+): m/z [M+Na]+ calcd
for C17H28F2NaO2SiBr: 353.1719, found: 353.1719.
4-{2-[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]ethyl}-3,5-di-
fluorophenyl sulfamate (14): As general method B using ClSO2NH2
(0.45m, 4.0 mL), DMA (2 mL) and 14h (0.095 g, 0.28 mmol). The
crude product was purified using the CombiFlash system (CHCl3/
acetone) to give the title compound (0.062 g, 53%) as an amor-
phous solid; 1H NMR (270 MHz, [D6]DMSO): d=2.92 (2H, t, J=
7.5 Hz, CH2), 4.04 (2H, t, J=7.5 Hz, CH2), 6.60 (2H, AA’BB’, ArH),
7.06–7.13 (2H, m, ArH), 7.75 (2H, AA’BB’, ArH), 8.25 (2H, brs, NH2),
8.93 ppm (2H, s, 2ꢃCHN); LC–MS (ES+): tR =1.19 min, m/z (%):
421.1 (100) [M+H]+; HRMS (ES+): m/z [M+H]+ calcd for
C17H15F2N6O3S: 421.0889, found: 421.0895; HPLC: tR =1.26 min
(>99%), (CH3CN/H2O, 90:10).
(4-Bromomethyl-2-difluoromethylphenoxy)triisopropylsilane
(15e): A solution of PBr3 (0.26 g, 0.96 mmol) in CH2Cl2 (6 mL) was
added dropwise to a cooled (08C) solution of 15d (0.64 g,
1.94 mmol) in CH2Cl2 (6 mL). The reaction mixture was allowed to
warm to room temperature and was stirred for 1 h. Aqueous
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ChemMedChem 2013, 8, 779 – 799 791

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1
NaHCO3 (sat., 10 mL) and CH2Cl2 (30 mL) were added and the
layers were separated. The organic layer was washed with H2O (2ꢃ
50 mL) and brine (50 mL) then dried (MgSO4) and the solvent was
removed in vacuo. The solvent was removed in vacuo, and the
crude product was purified using Flashmaster II (EtOAc/hexane) to
give the title compound as a white crystalline solid (0.58 g, 76%):
(0.10 g, 90%): mp: 148–1518C; H NMR (270 MHz, [D6]DMSO): d=
5.19 (2H, s, CH2), 6.76 (2H, m, AA’BB’), 7.10 (1H, t, J=55.4 Hz,
CHF2), 7.43 (1H, d, J=8.4 Hz, ArH), 7.58–7.67 (2H, m, ArH), 7.78
(2H, m, AA’BB’), 8.38 (2H, s, NH2), 8.87 ppm (2H, s, 2ꢃCHN);
13C NMR (68 MHz, [D6]DMSO): d=56.9 (CH2), 103.6 (C), 111.7 (CH, t),
114.3 (2ꢃCH), 119.6 (C), 123.4 (CH), 127.0 (CH, t), 127.5 (C) 127.9
(C), 132.8 (CH), 134.5 (2ꢃCH), 143.9 (2ꢃCH), 148.0 (C, t), 151.9 ppm
(C); LCMS (APCIꢀ): m/z (%): 419.3 (100) [MꢀH]ꢀ, 340.4 (20), 271.3
(20); HRMS (FAB+): m/z [M+H]+ calcd for C17H15N6O3F2S: 421.0889,
found: 421.0889; HPLC: tR =1.81 min (>99%), (CH3CN/H2O, 90:10).
1
mp: 43–458C; H NMR (270 MHz, CDCl3): d=1.02–1.31 (21H, m, 3ꢃ
CH, 6ꢃCH3), 4.41 (2H, s, CH2), 6.74 (1H, d, J=8.5 Hz, ArH), 6.85 (1H,
t, J=55.7 Hz, CH2F), 7.28 (1H, d, J=8.5 Hz, ArH), 7.49 ppm (1H, d,
J=2.1 Hz, ArH); 13C NMR (68 MHz, CDCl3): d=13.0 (3ꢃCH), 18.0 (6ꢃ
CH3), 32.2 (CH2), 111.6 (CH, t), 118.8 (CH), 124.9 (C, t), 127.4 (CH, t),
130.3 (C), 132.6 (CH), 154.3 ppm (C, t); LRMS (FAB+): m/z (%): 393.1
(100) [M]+, 313.1 (80), 227.1 (50); HRMS (ES+): m/z [M+Na]+ calcd
for C17H27F2NaOSiBr: 415.0875, found: 415.0875.
4-Benzyloxy-N-(4-cyanophenyl)-N-[1,2,4]triazol-4-ylbenzamide
(16a): A suspension of 4-benzyloxybenzoic acid (1.00 g, 4.39 mmol)
in SOCl2 (10 mL) was heated at reflux until gas evolution ceased
and was then allowed to cool and SOCl2 was removed in vacuo.
The residue was suspended in CH2Cl2 (40 mL) and 10 (0.65 g,
3.51 mmol) and Et3N (3.55 g, 35.1 mmol) were sequentially added
and the mixture was stirred for 2 h. The reaction mixture was con-
centrated in vacuo and the residue was dissolved in EtOAc (60 mL)
and washed with 1m aq. HCl (60 mL), H2O (60 mL), NaHCO3
(60 mL) and brine (60 mL). The organic layer was dried (MgSO4)
and the solvent was removed in vacuo. The crude product was pu-
rified using Flashmaster II (EtOAc/hexane) to give the title com-
pound as a white crystalline solid (0.92 g, 67%): mp: 205–207.58C;
1H NMR (270 MHz, [D6]DMSO): d=5.09 (2H, s, CH2), 7.00 (2H, s,
AA’BB’), 7.27–7.53 (9H, m, ArH), 7.88 (2H, s, AA’BB’, ArH), 9.10 ppm
(2H, s, 2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO): d=70.0 (CH2),
110.8 (C), 115.1 (2ꢃCH), 118.5 (C), 124.3 (C), 126.7 (2ꢃCH), 128.5
(2ꢃCH), 128.6 (CH), 129.0 (2ꢃCH), 131.5 (2ꢃCH), 134.3 (2ꢃCH),
136.8 (C), 143.9 (2ꢃCH), 145.7 (C), 161.5 (C), 167.8 ppm (C); LC–MS
(APCIꢀ): tR =3.38 min, m/z (%): 396.3 (100) [M+H]+, 327.3 (60),
299.3 (20); HRMS (ES+): m/z [M+H]+ calcd for C23H18N5O2:
396.1455, found: 396.1444.
4-[(3-Difluoromethyl-4-triisopropylsilanyloxybenzyl)-[1,2,4]tria-
zol-4-ylamino]benzonitrile (15 f): 15e (0.18 g, 0.98 mmol) was
added to a cooled (08C) suspension of NaH (60% in mineral oil,
0.039 g, 0.98 mmol) in DMF (12 mL) and the resulting solution was
stirred for 30 min at room temperature. A solution of 10 (0.42 g,
1.07 mmol) in DMF (3 mL) was added and after stirring overnight
the reaction mixture was poured onto H2O (40 mL) and the prod-
uct was extracted with EtOAc (2ꢃ40 mL). The combined organics
were washed with H2O (4ꢃ60 mL) and brine (60 mL), then dried
(MgSO4) and the solvent was removed in vacuo. The crude product
was purified using Flashmaster II (EtOAc/hexane) to give the title
compound as a white solid (0.084 g, 74%): mp: 85.0–87.58C;
1H NMR (270 MHz, CDCl3): d=1.03–1.35 (21H, m, 3ꢃCH, 6ꢃCH3),
4.83 (2H, s, CH2), 6.66 (2H, AA’BB’, ArH), 6.79 (1H, d, J=8.4, ArH),
6.90 (1H, t, J=55.4 Hz, CHF2), 7.06 (1H, d, J=8.4 Hz, ArH), 7.42 (1H,
s, ArH), 7.58 (2H, AA’BB’, ArH), 8.09 ppm (2H, s, 2ꢃCHN); 13C NMR
(68 MHz, CDCl3): d=12.9 (3ꢃCH), 18.0 (6ꢃCH3), 57.7 (CH2), 105.4
(C), 111.3 (CH, t), 113.6 (2ꢃCH), 118.6 (CH), 119.4 (CH), 125.6 (C),
125.7 (C, t), 126.5 (CH, t), 131.6 (CH), 134.3 (2ꢃCH), 142.7 (2ꢃCH),
150.5 (C), 154.9 ppm (C, t); LCMS (APCI+): m/z (%): 498.5 (100) [M+
H]+, 429.5 (15); HRMS (ES+): m/z [M+H]+ calcd for C26H34F2N5OSi:
498.2495, found: 498.2463.
4-(Benzyloxy)-N-(4-cyanophenyl)-N-(4H-1,2,4-triazol-4-yl)benzo-
thioamide (16b): A mixture of 16a (1.40 g, 3.54 mmol) and Lawes-
son’s reagent (1.07 g, 2.65 mmol) in xylenes (140 mL) was heated
at reflux for 42 h. The reaction mixture was allowed to cool and
the solvent was removed in vacuo. The residue was dissolved in
EtOAc (75 mL) and washed with H2O (75 mL) and brine (75 mL)
then dried (MgSO4) and the solvent was removed in vacuo. The
crude product was purified using Flashmaster II (EtOAc/hexane) to
give the title compound as a yellow solid (0.81 g, 56%): 1H NMR
(270 MHz, CDCl3) d=5.10 (2H, s, CH2), 6.94 (2H, AA’BB’, ArH), 7.32–
7.45 (5H, m, ArH), 7.50–7.59 (4H, m, ArH), 7.89 (2H, AA’BB’, ArH),
9.19 ppm (2H, s, 2ꢃCHN); LC–MS (APCI+): tR =4.41 min, m/z (%):
412.4 (100) [M+H]+, 214.3 (20), 119.1 (30). HRMS (FAB+): m/z [M+
H]+ calcd for C23H18N5OS: 412.1227, found 412.1230.
4-{[3-(Difluoromethyl)-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl]a-
mino}benzonitrile (15g): A solution of TBAF (IM in THF, 0.5 mL)
was added to a solution of 15 f (0.32 g, 0.64 mmol) in THF (6 mL)
and the reaction mixture was stirred for 15 min. A few drops of
AcOH were added until the solution became colourless and then
the reaction mixture was poured onto H2O (20 mL) and the prod-
uct extracted with EtOAc (2ꢃ20 mL). The combined organic layers
were washed with H2O (40 mL), sat. NaHCO3 solution (40 mL) and
brine (40 mL), then dried (MgSO4) and the solvent was removed in
vacuo. The crude product was purified by trituration with hexane
to give the title compound as a white solid (0.19 g, 95%): mp:
1758C (dec.); 1H NMR (270 MHz, [D6]DMSO): d=4.99 (2H, s, CH2),
6.75–6.86 (3H, m, ArH), 6.99 (1H, t, J=55.4 Hz, CHF2), 7.22 (1H, d,
J=8.4 Hz, ArH), 7.33 (1H, s, ArH), 7.77 (2H, AA’BB’, ArH), 8.74 (2H,
s, 2ꢃCHN), 10.35 ppm (1H, s, OH); 13C NMR (68 MHz, [D6]DMSO):
d=56.8 (CH2), 103.4 (C), 112.7 (CH, t), 114.4 (2ꢃCH), 116.7 (CH),
119.6 (C), 120.8 (C, t), 125.4 (C), 127.2 (CH, t), 133.1 (CH), 134.5 (2ꢃ
CH), 143.9 (2ꢃCH), 152.1 (C), 156.0 ppm (C, t); 19F NMR (376 MHz,
CDCl3): d=ꢀ115.2 ppm (d); LCMS (APCI+): m/z (%) 340.3 (100)
[MꢀH]ꢀ, 271.3 (20); HRMS (FAB+): m/z [M+H]+ calcd for
C17H14F2N5O: 342.1161, found: 342.1158; HPLC: tR =1.75 min (95%),
(CH3CN/H2O, 90:10).
4-{[(4-(Benzyloxy)phenyl)difluoromethyl](4H-1,2,4-triazol-4-yl)a-
mino}benzonitrile (16c): SbCl3 (0.007 g, 0.031 mmol) and Deoxo-
Fluorꢁ (0.17 g, 0.77 mmol) were sequentially added to a solution of
16b (0.12 g, 0.29 mmol) in CH2Cl2 (3 mL). The reaction mixture was
stirred overnight and was quenched by the cautious addition of
sat. aq. NaHCO3 (20 mL). CH2Cl2 (15 mL) was added and the layers
were separated and the organic layer was washed with H2O
(15 mL) then dried (MgSO4) and the solvent was removed in vacuo.
The crude product was purified using Flashmaster II (EtOAc/
hexane) to give the title compound as a yellow solid (0.087 g,
1
71%): mp: 167–1698C; H NMR (270 MHz, [D6]DMSO): d=5.11 (2H,
s, CH2), 7.09 (2H, AA’BB’, ArH), 7.32–7.48 (7H, m, ArH), 7.66 (2H,
AA’BB’, ArH), 7.87 (2H, AA’BB’, ArH), 9.11 ppm (2H, s, 2ꢃCHN);
13C NMR (68 MHz, [D6]DMSO): d=70.1 (CH2), 110.0 (C), 115.6 (2ꢃ
CH), 118.6 (C), 121.9 (t, C), 123.3 (t, C), 124.5 (2ꢃCH), 128.5 (2ꢃCH),
128.6 (CH), 129.0 (2ꢃCH), 129.0 (2ꢃCH), 134.5 (2ꢃCH), 136.9 (C),
4-{[(4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-2-(di-
fluoromethyl)phenyl sulfamate (15): As general method B using
ClSO2NH2 (0.6m, 2.2 mL), DMA (2 mL) and 15g (0.090 g,
0.26 mmol). The title compound was obtained as a white solid
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144.5 (2ꢃCH), 145.1 (C), 161.3 ppm (C); LC–MS (APCI+): tR =
4.49 min, m/z (%): 418.3 (100) [M+H]+; HRMS (FAB+): m/z [M+
H]+ calcd for C23H18F2N5O: 418.1474, found: 418.1474.
(0.6m, 3 mL), DMA (3 mL) and 17c (0.12 g, 0.37 mmol). The crude
product was purified using Flashmaster II (EtOAc/hexane) and was
then precipitated from EtOAc/hexane to give the title compound
as a white amorphous solid (0.12 g, 81%): 1H NMR (270 MHz,
[D6]DMSO): d=5.18 (2H, s, CH2), 6.72 (2H, AA’BB’, ArH), 7.20 (1H,
dd, J=8.4 Hz, 2.2, ArH), 7.42 (1H, d, J=2.2 Hz, ArH), 7.48 (1H, d,
J=8.4 Hz, ArH), 7.77 (2H, AA’BB’, ArH), 8.19 (2H, s, NH2), 8.85 ppm
(2H, s, 2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO): d=54.7 (CH2),
103.0 (C), 113.6 (2ꢃCH), 119.0 (C), 121.3 (CH), 123.2 (CH), 130.5 (C),
131.6 (CH), 133.5 (C), 134.1 (2ꢃCH), 143.4 (2ꢃCH), 150.3 (C),
151.2 ppm (C); LC–MS (ESꢀ): tR =0.91 min, m/z (%): 403.4 (100)
[MꢀH]ꢀ; HRMS (ESꢀ): m/z [MꢀH]ꢀ calcd for C16H12ClN6O3S:
403.0386, found: 403.0386; HPLC: tR =3.26 min (99%), (CH3CN/H2O,
90:10).
4-{[Difluoro(4-hydroxyphenyl)methyl](4H-1,2,4-triazol-4-yl)ami-
no}benzonitrile (16d): As general method A using 10% Pd/C
(8 mg), 16c (0.04 g, 0.096 mmol) and THF/MeOH (1:1, 4 mL). The
crude product was purified using Flashmaster II (EtOAc/hexane) to
give the title compound as a white solid (0.019 g, 61%): mp: 143–
1458C; 1H NMR (270 MHz, [D6]DMSO): d=6.79 (2H, AA’BB’, ArH),
7.36 (2H, AA’BB’, ArH), 7.50 (2H, AA’BB’, ArH), 7.87 (2H, AA’BB’,
ArH), 9.08 (2H, s, 2ꢃCHN), 10.21 ppm (1H, brs, OH); 13C NMR
(100 MHz, [D6]DMSO): d=109.3 (C), 115.6 (2ꢃCH), 118.1 (C), 120.9
(t, C), 121.6 (t, C), 123.7 (2ꢃCH), 128.4 (2ꢃCH), 133.9 (2ꢃCH), 144.0
(2ꢃCH), 144.7 (C), 160.2 ppm (C); LC–MS (APCI+): tR =1.25 min, m/z
(%): 327.46 (80) [M]+, 21.3.1 (100); HRMS (FAB+): m/z [M+H]+
calcd for C16H12F2N5O: 328.1004, found: 328.1004; HPLC: tR =
3.54 min (>99%), (CH3CN/H2O, 70:30).
2,6-Dichloro-4-hydroxybenzaldehyde (18a): This was prepared
according to the method as described by Bringmann et al.[53]
3,5-Dichloro-4-(hydroxymethyl)phenol (18b): A solution of NaBH4
(0.070 g, 1.84 mmol) in H2O (0.5 mL) was added dropwise to a solu-
tion of 18a (0.13 g, 0.68 mmol) in EtOH (2 mL). After stirring for
1 h, the reaction was quenched by the cautious addition of aq. HCl
(3m, 5 mL), EtOAc (10 mL) and H2O (10 mL). The layers were sepa-
rated and the aqueous was extracted with EtOAc (10 mL). The or-
ganic layers were combined, washed with H2O (2ꢃ20 mL) and aq.
sat. NaHCO3 (20 mL) then dried (MgSO4) and the solvent was re-
moved in vacuo to give the title compound as a white crystalline
4-[N-(4-cyanophenyl)-N-(4H-1,2,4-triazol-4-yl)fluorocarbonyl]-
phenyl sulfamate (16): As general method B using ClSO2NH2
(0.6m, 1.2 mL), DMA (3 mL) and 16d (0.050 g, 0.15 mmol). The
crude product was purified by precipitation from EtOAc/hexane to
give the title compound as a white solid (0.045 g, 76%): mp:
139.5–1428C; 1H NMR (270 MHz, [D6]DMSO): d=7.38 (2H, AA’BB’,
ArH), 7.44 (2H, AA’BB’, ArH), 7.88 (4H, 2ꢃAA’BB’, ArH), 8.21 (2H, s,
SO2NH2), 9.14 ppm (2H, s, 2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO):
d=109.9 (C), 118.0 (C), 120.7 (t, C), 122.3 (t, C), 122.5 (2ꢃCH), 124.3
(2ꢃCH), 128.7 (2ꢃCH), 134.1 (2ꢃCH), 143.9 (2ꢃCH), 144.2 (C),
152.6 ppm (C); LC–MS (APCIꢀ): tR =2.88 min, m/z (%): 405.4 (100)
[MꢀH]ꢀ, 212.0 (60), 184 (50); HRMS (FAB+): m/z [M+H]+ calcd for
C16H13F2N6O3S: 407.0732, found: 407.0734; HPLC: tR =10.73 min
(97.3%), (CH3CN/H2O, 50:50).
1
solid (0.12 g, 93%): mp: 169–1718C; H NMR (270 MHz, [D6]DMSO):
d=4.56 (2H, d, J=5.0 Hz, CH2), 5.01 (1H, t, J=5.0 Hz, ArH), 6.82
(2H, s, ArH), 10.40 ppm (1H, s, OH); LC–MS (ES+): m/z (%): 191.1
(100) [M]+.
4-[(2,6-Dichloro-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl)amino]-
benzonitrile (18c): A solution of 18b (0.30 g, 1.56 mmol) in SOCl2
(3 mL) was stirred for 2 h (with heating when needed to dissolve)
then the SOCl2 was removed in vacuo. The residue was dissolved
in DMF (6 mL) and 10 (1.01 g, 5.46 mmol) and K2CO3 (3.60 g,
26.1 mmol) were added and the reaction mixture was stirred for
48 h. The mixture was poured onto H2O (50 mL) and the product
was extracted with EtOAc (2ꢃ30 mL). The combined organic layers
were washed with H2O (4ꢃ30 mL) and brine (30 mL), then dried
(MgSO4) and the solvent was removed in vacuo. The crude product
was purified using the CombiFlash system (CH2Cl2/acetone) to give
the title compound as a white solid (0.71 g, 38%): mp: 2308C
3-Chloro-4-(hydroxymethyl)phenol (17a): This was prepared ac-
cording to the method described by Matysiak et al.;[52] yield=14%.
3-Chloro-4-(chloromethyl)phenol (17b): A solution of 17a (0.10 g,
0.63 mmol) in SOCl2 (2 mL) was stirred for 2 h. The reaction mixture
was concentrated in vacuo and the product was used directly in
1
next step: H NMR (270 MHz, [D6]DMSO): d=4.74 (2H, s, CH2), 6.75
(1H, dd, J=8.4 Hz, 2.5 ArH), 6.88 (1H, d, J=2.5 Hz, ArH), 7.39 ppm
(1H, d, J=8.4 Hz, ArH).
4-[(2-Chloro-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl)amino]benzo-
nitrile (17c): Compound 10 (0.12 g, 0.64 mmol) and K2CO3 (0.43 g,
3.12 mmol) were sequentially added to a solution of 17b in DMF
(5 mL). The reaction mixture was stirred overnight and then
poured onto H2O (25 mL) and extracted with EtOAc (2ꢃ25 mL).
The organic layers were combined, washed with H2O (3ꢃ25 mL)
and brine (25 mL), dried (MgSO4) and the solvent was removed in
vacuo. The crude product was purified using Flashmaster II (EtOAc/
hexane) to give the title compound as a white powder (0.18 g,
100%): 1H NMR (270 MHz, [D6]DMSO): d=5.00 (2H, s, CH2), 6.62
(1H, dd, J=8.4 Hz, 2.5, ArH), 6.78–6.80 (3H, m, ArH), 7.05 (1H, d,
J=8.4 Hz, ArH), 7.76 (2H, AA’BB’, ArH), 8.71 (2H, s, 2ꢃCHN),
10.05 ppm (1H, s, OH); 13C NMR (100 MHz, [D6]DMSO): d=54.7
(CH2), 103.0 (C), 113.6 (2ꢃCH), 119.0 (C), 121.3 (CH), 123.2 (CH),
130.5 (C), 131.6 (CH), 133.5 (C), 134.1 (2ꢃCH), 143.4 (2ꢃCH), 150.3
(C), 151.2 ppm (C); LC–MS (APCI+): tR =0.95 min, m/z (%): 326.4 (3)
[M+H]+, 257.3 (100), 141.1 (40); HRMS (FAB+): m/z [M+H]+ calcd
for C16H13ClN5O: 326.0803, found: 326.0804; HPLC: tR =3.14 min
(99%), (CH3CN/H2O, 90:10).
1
(dec.); H NMR (270 MHz, [D6]DMSO): d=5.17 (2H, s, CH2), 6.78.3–
6.86 (4H, m, ArH), 7.77 (2H, m, AA’BB’, ArH), 8.63 (2H, s, 2ꢃCHN),
10.60 ppm (1H, s, OH); 13C NMR (100 MHz, [D6]DMSO): d=50.7
(CH2), 102.7 (C), 113.5 (2ꢃCH), 115.8 (2ꢃCH), 119.1 (C), 119.4 (C),
133.9 (2ꢃCH), 136.4 (2ꢃC) 143.5 (2ꢃCH), 151.0 (C), 158.6 ppm (C);
LC–MS (ES+): tR =1.32 min, m/z (%): 360.2 (100) [M]+; HRMS (ES+):
m/z [M]+ calcd for C16H12Cl2N5O: 360.0413, found: 360.0405; HPLC:
tR =1.35 min (>99%), (CH3CN/H2O, 90:10).
3,5-Dichloro-4-{[(4-cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]me-
thyl}phenyl sulfamate (18): As general method B using ClSO2NH2
(0.5m, 8.0 mL), DMA (3 mL) and 18d (0.20 g, 0.56 mmol). The crude
product was purified using Flashmaster II (CH2Cl2/acetone) to give
the title compound as a white amorphous solid (0.13 g, 55%):
1H NMR (270 MHz, [D6]DMSO): d=5.32 (2H, s, CH2), 6.84 (2H, m,
AA’BB’, ArH), 7.42 (2H, s, ArH), 7.79 (2H, m, AA’BB’, ArH), 8.35 (2H,
brs, NH2), 8.69 ppm (2H, s, 2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO):
d=50.9 (CH2), 103.1 (C), 113.7 (2ꢃCH), 119.0 (C), 122.3 (2ꢃCH),
126.1 (C), 134.0 (2ꢃCH), 136.5 (2ꢃC), 143.5 (2ꢃCH), 150.4 (C),
150.9 ppm (C); LC–MS (ES+): tR =1.30 min, m/z (%): 439.0 (100)
[M+H]+; HRMS (ES+): m/z [M+H]+ calcd for C16H13Cl2N6OS:
3-Chloro-4-{[(4-cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-
phenyl sulfamate (17): As general method B using ClSO2NH2
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439.0141, found: 439.0141; HPLC: tR =1.31 min (>99%), (CH3CN/
H2O, 90:10).
(CH2Cl2/acetone) to give the title compound as a white solid
(0.14 g, 52%): mp: 233–2358C; H NMR (400 MHz, [D6]DMSO): d=
1
4.97 (2H, s, CH2), 6.63 (1H, dd, J=8.4, 2.4 Hz, ArH), 6.75 (2H,
AA’BB’, ArH), 6.98 (1H, d, J=2.4 Hz, ArH), 7.03 (1H, d, J=8.4 Hz,
ArH), 7.74 (2H, AA’BB’, ArH), 8.66 (2H, s, 2ꢃCHN), 9.97 ppm (1H, s,
OH); 13C NMR (100 MHz, [D6]DMSO): d=56.4 (CH2), 102.8 (C), 113.6
(2ꢃCH), 115.0 (CH), 119.0 (C), 119.4 (CH), 123.2 (C), 124.0 (C), 132.3
(CH), 133.9 (2ꢃCH), 143.2 (2ꢃCH), 151.2 (C), 158.4 ppm (C); LC–MS
(ES+): tR =1.21 min, m/z (%): 370.0 (100) [M+H]+; HRMS (ES+):
m/z [M+H]+ calcd for C16H13N5OBr: 370.0298, found: 370.0299.
3-Bromo-4-methylphenyl benzoate (19a): Benzoyl chloride
(1.65 g, 11.7 mmol) was added dropwise to a solution of 3-bromo-
4-methylphenol (2.00 g, 10.7 mmol) and pyridine (3 mL) in CH2Cl2
(20 mL). The solution was stirred for 1 h at room temperature, then
H2O was added and stirring was continued for 0.5 h. The organic
layer was separated, washed with 2m KHSO4 (20 mL) and brine
(10 mL), dried (MgSO4) and concentrated in vacuo. The residue was
recrystallised from MeOH to afford the title compound as a white
solid (2.35 g, 75%): mp: 74–758C (lit.[54] mp: 75–768C); 1H NMR
(400 MHz, [D6]DMSO): d=2.42 (3H, s, CH3), 7.09 (1H, dd, J=8.6 Hz,
2.3 Hz, ArH), 7.29 (1H, d, J=8.6 Hz, ArH), 7.44 (1H, d, J=2.3 Hz,
ArH), 7.48–7.54 (2H, m, ArH), 7.61–7.68 (1H, m, ArH), 8.16–
8.22 ppm (2H, m, ArH); 13C NMR (100 MHz, [D6]DMSO): d=22.3
(CH3), 120.6 (CH), 124.5 (C), 125.6 (CH), 128.6 (2ꢃCH), 129.2 (C),
130.2 (2ꢃCH), 131.0 (CH), 133.7 (CH), 135.5 (C), 149.1 (C),
164.9 ppm (C); LRMS (ES+): m/z (%): 290.6 (100) [M+H]+.
3-Bromo-4-{[(4-cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-
phenyl sulfamate (19): As general method B using ClSO2NH2
(0.6m, 2.2 mL), DMA (2 mL) and 19d (0.105 g, 0.28 mmol). The
crude product was purified using the CombiFlash system (CHCl3/
acetone) to give the title compound as a white solid (0.094 g,
1
74%): H NMR (400 MHz, [D6]DMSO): d=5.13 (2H, s, CH2), 6.71 (2H,
AA’BB’, ArH), 7.22 (1H, dd, J=8.4, 2.4 Hz, ArH), 7.44 (1H, d, J=
2.4 Hz, ArH), 7.55 (1H, d, J=2.4 Hz, ArH), 7.75 (2H, AA’BB’, ArH),
8.13 (2H, s, NH2), 8.81 ppm (2H, s, 2ꢃCHN); 13C NMR (126 MHz,
[D6]DMSO): d=56.9 (CH2), 103.0 (C), 113.6 (2ꢃCH), 119.0 (C), 121.7
(CH), 123.2 (C), 126.3 (CH), 131.4 (CH), 132.0 (C), 134.0 (2ꢃCH),
143.3 (2ꢃCH), 150.2 (C), 151.1 ppm (C); LC–MS (ES+): tR =1.19 min,
m/z (%): 448.9 (100) [M+H]+; HRMS (ES+): m/z [M+H]+ calcd for
C16H14N6O3SBr: 449.0032, found: 449.0026.
3-Bromo-4-(bromomethyl)phenyl benzoate (19b): A mixture of
19a (2.30 g, 7.90 mmol), NBS (1.79 g, 7.90 mmol) and benzoyl per-
oxide (5 mg) in CCl4 (20 mL) was heated at reflux for 1 h 30 min
with small additional portions of benzoyl peroxide added every
15 min. After cooling to room temperature, the reaction mixture
was filtered and the solvent was removed in vacuo from the fil-
trate. The crude product was purified using the CombiFlash system
(PE/EtOAc) to give the title compound as a white solid (1.49 g,
(E)-N-[4-(Benzyloxy)benzylidene]aniline (20a): A mixture of 4-
benzyloxybenzaldehyde (5.31 g, 25.0 mmol), aniline (2.33 g,
25 mmol), p-TsOH·H2O (0.10 g) and EtOH (150 mL) was heated at
reflux for 0.5 h. The reaction mixture was allowed to cool to room
temperature and the crystals that formed were collected, washed
with EtOH and dried under high vacuum to afford the title com-
pound as light-yellow fine plates (6.11 g, 85%): mp: 111–1128C;
1H NMR (400 MHz, CDCl3) d=5.14 (2H, s, CH2), 7.07 (2H, AA’BB’,
ArH), 7.17–7.25 (3H, m, ArH), 7.33–7.49 (7H, m, ArH), 7.87 (2H,
AA’BB’, ArH), 8.39 ppm (1H, s, CH); 13C NMR (100 MHz, CDCl3) d=
70.1 (CH2), 115.1 (2ꢃCH), 120.9 (2ꢃCH), 125.5 (CH), 127.5 (2ꢃCH),
128.1 (CH), 128.6 (2ꢃCH), 129.1 (2ꢃCH), 129.5 (C), 130.5 (2ꢃCH),
136.4 (C), 152.3 (C), 159.6 (CH), 161.4 ppm (C); Anal. calcd for
C20H17NO: C 83.59, H 5.96, N 4.87, found: C 83.6, H 5.96, N 4.87.
1
51%): H NMR (400 MHz, [D6]DMSO): d=4.62 (2H, s, CH2), 7.21 (1H,
dd, J=8.4, 2.4 Hz, ArH), 7.50–7.54 (4H, m, ArH), 7.63–7.68 (1H, m,
ArH), 8.16–8.19 ppm (2H, m, ArH); 13C NMR (100 MHz, [D6]DMSO):
d=32.5 (CH2), 121.5 (CH), 124.5 (C), 126.7 (CH), 128.7 (2ꢃCH),
129.0 (C), 130.3 (2ꢃCH), 131.8 (CH), 134.0 (CH), 134.7 (C), 151.2 (C),
1645.6 ppm (C).
3-Bromo-4-{[(4-cyanophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}-
phenyl benzoate (19c): NaH (60% dispersion in mineral oil,
0.048 g, 1.20 mmol) was added to a solution of 10 (0.21 g,
1.14 mmol) in DMF (10 mL). After stirring for 30 min, 19b (0.38 g,
1.03 mmol) was added and stirring was continued for 48 h. The re-
action mixture was poured onto H2O (25 mL) and the product was
extracted with EtOAc (3ꢃ30 mL). The combined organic layers
were washed with H2O (4ꢃ60 mL) and brine (60 mL) then dried
(MgSO4) and the solvent was removed in vacuo. The crude product
was purified using the CombiFlash system (CH2Cl2/acetone) to give
the title compound as a white powder (0.41 g, 85%): mp: 213–
2168C; 1H NMR (400 MHz, [D6]DMSO): d=5.15 (2H, s, CH2), 6.75
(2H, AA’BB’, ArH), 7.28 (1H, dd, J=8.4, 2.4 Hz, ArH), 7.44 (1H, d, J=
8.4 Hz, ArH), 7.57–7.62 (2H, m, ArH), 7.68–7.79 (4H, m, ArH), 8.08–
8.12 (2H, m, ArH), 8.81 ppm (2H, s, 2ꢃCHN); 13C NMR (100 MHz,
[D6]DMSO): d=56.9 (CH2), 103.1 (C), 113.7 (2ꢃCH), 119.0 (C), 121.7
(CH), 123.3 (C), 126.6 (CH), 128.5 (C), 129.0 (2ꢃCH), 129.9 (2ꢃCH),
131.3 (C), 131.5 (CH), 134.0 (2ꢃCH), 134.2 (CH), 143.2 (2ꢃCH),
150.9 (C), 151.2 (C), 164.2 ppm (C); LC–MS (ES+): tR =1.40 min, m/z
(%): 474.1 (100) [M+H]+; HRMS (ES+): m/z [M+H]+ calcd for
C23H17N5O2Br: 474.0560, found: 474.0569.
N-[4-(Benzyloxy)benzyl]aniline (20b): NaBH4 (1.21 g, 31.99 mmol)
was added to
a cooled (08C) suspension of 20a (5.90 g,
20.53 mmol) in THF (50 mL) and EtOH (50 mL). The mixture was al-
lowed to warm to room temperature and stirring was continued
for 18 h. The reaction mixture was poured into H2O (250 mL) and
the products were extracted with EtOAc (3ꢃ100 mL). The com-
bined organic layers were washed with H2O (100 mL) and brine
(50 mL), dried (MgSO4) and concentrated under reduced pressure.
The residue was dissolved in CHCl3 and passed through a short
SiO2 column (~5 cm). The volatiles were removed in vacuo and the
residue was recrystallised from CHCl3/PE to afford the title com-
pound as fine colourless needles (5.57 g, 94%): mp: 75–768C;
1H NMR (400 MHz, [D6]DMSO): d=3.96 (1H, s, NH), 4.28 (2H, s,
CH2), 5.09 (2H, s, CH2), 6.67 (2H, d, J=8.6 Hz, ArH), 6.72–6.78 (1H,
m, ArH), 6.90 (2H, AA’BB’, ArH), 7.18–7.23 (2H, m, ArH), 7.31 (2H,
AA’BB’, ArH), 7.34–7.48 ppm (5H, m, ArH); 13C NMR (100 MHz,
[D6]DMSO): d=47.7 (CH2), 70.0 (CH2), 112.8 (2ꢃCH), 114.9 (2ꢃCH),
117.5 (CH), 127.4 (2ꢃCH), 127.9 (CH), 128.6 (2ꢃCH), 128.8 (2ꢃCH),
129.2 (2ꢃCH), 131.7 (C), 137.0 (C), 148.2 (C), 158.0 ppm (C); LRMS
(ES+): m/z (%): 289.9 (25) [M+H]+, 196.8 (100); HRMS (ES+): m/z
[M+H]+ calcd for C20H20NO: 290.1539, found: 290.1533; Anal.
calcd for C20H19NO: C 83.01, H 6.62, N 4.84, found: C 83.0, H 6.56, N
4.80.
4-[(2-Bromo-4-hydroxybenzyl)(4H-1,2,4-triazol-4-yl)amino]benzo-
nitrile (19d): KOH (0.25 g, 4.46 mmol) was added to a suspension
of 19c (0.35 g, 0.74 mmol) in MeOH (5 mL). After stirring for 2 h
the reaction mixture was neutralised with 1m aq. HCl and the
product was extracted with EtOAc (3ꢃ30 mL). The combined or-
ganic layers were washed with sat. aq. NaHCO3 (60 mL) and brine
(60 mL) then dried (MgSO4) and the solvent was removed in vacuo.
The crude product was purified using the CombiFlash system
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1-[4-(Benzyloxy)benzyl]-1-phenylhydrazine (20c): A solution of
NaNO2 (2.07 g, 30 mmol) in H2O (10 mL) was slowly added to
containing 1 equiv acetone: mp: 140–1428C; 1H NMR (400 MHz,
[D6]DMSO): d=4.97 (2H, s, CH2), 6.65–6.75 (2H, m, ArH), 6.95–7.05
(1H, m, ArH), 7.21 (2H, AA’BB’, ArH), 7.28–7.38 (2H, m, ArH), 7.42
(2H, AA’BB’, ArH), 8.03 (2H, s, NH2), 8.82 ppm (2H, s, 2ꢃCHN);
13C NMR (100 MHz, [D6]DMSO): d=57.3 (CH2), 114.7 (2ꢃCH), 122.1
(CH), 122.2 (2ꢃCH), 129.5 (2ꢃCH), 129.7 (2ꢃCH), 134.0 (C), 143.4
(2ꢃCH), 148.6 (C), 149.7 ppm (C); LRMS (ES+): m/z (%): 346.0 (100)
[M+H]+; HRMS (ES+): m/z [M+H]+ calcd for C15H16N5O3S:
346.0968, found: 346.0961; Anal. calcd for C15H15N5O3S·C3H6O: C
53.59, H 5.25, N 17.36, found: C 53.3, H 5.36, N 17.6.
a
cooled (08C) intensively stirred mixture of 20b (5.79 g,
20.0 mmol), CHCl3 (50 mL) and 2m H2SO4 (40 mL). The mixture was
stirred for 0.5 h and then the organic layer was separated, washed
with brine (20 mL), dried (Na2SO4) and concentrated in vacuo. The
residue was dissolved in THF (30 mL) and added to a suspension
of LiAlH4 (1.44 g, 37.9 mmol) in THF (10 mL). The reaction mixture
was stirred overnight at room temperature, then H2O (2 mL) and
5m NaOH (3 mL) were added carefully. The inorganic salts were fil-
tered off and washed with THF, the organic fraction was dried over
Na2SO4 and the volatiles were removed in vacuo. The residue was
purified using the CombiFlash Rf (CH2Cl2/MeOH) to afford the title
compound as a light-yellow solid (5.23 g, 86%): mp: 72–738C;
1H NMR (400 MHz, [D6]DMSO): d=3.50 (2H, s, NH2), 4.52 (2H, s,
CH2), 5.06 (2H, s, CH2), 6.80–6.85 (1H, m, ArH), 6.96 (2H, AA’BB’,
ArH), 7.11 (2H, d, J=8.6 Hz, ArH), 7.23 (2H, AA’BB’, ArH), 7.27–7.46
(7H, m, ArH); 13C NMR (100 MHz, [D6]DMSO): d=59.8 (CH2), 70.0
(CH2), 113.8 (2ꢃCH), 115.0 (2ꢃCH), 118.6 (CH), 127.4 (2ꢃCH), 128.0
(CH), 128.6 (2ꢃCH), 129.0 (2ꢃCH), 129.3 (2ꢃCH), 129.6 (C), 137.0
(C), 151.8 (C), 158.2 ppm (C); LRMS (ES+): m/z (%): 305.0 (100) [M+
H]+; HRMS (ES+): m/z [M+H]+ calcd for C20H21N2O: 305.1648,
found: 305.1653; Anal. calcd for C20H20N2O: C 78.92, H 6.62, N 9.20,
found: C 79.0, H 6.60, N 9.23.
(4-Benzyloxybenzylidene)-(3,5-difluorophenyl)amine (21a):
A
mixture of 3,5-difluoroaniline (1.94 g, 15 mmol), 4-benzyloxybenzal-
dehyde (3.18 g, 15 mmol) and p-TsOH·H2O (0.10 g) in EtOH (50 mL)
was heated at reflux for 1 h. The reaction mixture was allowed to
cool to room temperature and the crystals that formed were col-
lected, washed with EtOH and dried under high vacuum to afford
the title compound as colourless plates (3.88 g, 80%): mp: 78–
1
798C; H NMR (400 MHz, [D6]DMSO): d=5.14 (2H, s, CH2), 6.60–6.73
(3H, m, ArH), 7.05 (2H, AA’BB’, ArH), 7.35–7.48 (5H, m, ArH), 7.82
(2H, AA’BB’, ArH), 8.31 ppm (1H, s, CH); 13C NMR (100 MHz,
[D6]DMSO): d=70.1 (CH2), 100.6 (t, CH), 104.1 (2ꢃCH, m), 115.1 (2ꢃ
CH), 127.5 (2ꢃCH), 128.2 (CH), 128.7 (2ꢃCH), 130.8. (C), 130.9 (2ꢃ
CH), 136.2 (C), 155.0 (C, t), 161.1 (CH), 161.9 (C), 163.2 ppm (2ꢃC,
dd); LRMS (ES+): m/z (%): 324.5 (100) [M+H]+; Anal. calcd for
C20H15F2NO: C 74.29, H 4.68, N 4.33, found: C 74.3, H 4.69, N 4.14.
N-[4-(Benzyloxy)benzyl]-N-phenyl-4H-1,2,4-triazol-4-amine (20d):
Dimethylformamide diazine dihydrochloride[37] (7.07 g, 32.86 mmol)
was added to a solution of 20c (5.00 g, 16.43 mmol) in pyridine
(10 mL) and the mixture was heated at reflux for 2 h. After cooling
to room temperature EtOAc (60 mL) and H2O (30 mL) were added,
the organic layer was separated, washed with 2m KHSO4 solution
(2ꢃ30 mL) and brine (30 mL), dried (Na2SO4) and concentrated
under reduced pressure. The residue was recrystallised from MeOH
to afford the title compound as pale-yellow plates (3.12 g, 53%):
mp: 165–1678C; 1H NMR (400 MHz, [D6]DMSO): d=4.87 (2H, s,
CH2), 5.05 (2H, s, CH2), 6.77 (2H, AA’BB’, ArH), 6.92–6.96 (2H, m,
ArH), 6.99–7.04 (1H, m, ArH), 7.24 (2H, AA’BB’, ArH), 7.29–7.46 (7H,
m, ArH), 8.74 ppm (2H, s, 2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO):
d=57.3 (CH2), 69.2 (CH2), 114.7 (2ꢃCH), 114.8 (2ꢃCH), 122.1 (CH),
127.4 (C), 127.8 (2ꢃCH), 127.9 (CH), 128.4 (2ꢃCH), 129.4 (2ꢃCH),
130.1 (2ꢃCH), 136.9 (C), 143.4 (2ꢃCH), 148.8 (C), 158.0 ppm (C);
LRMS (ES+): m/z (%): 357.1 (100) [M+H]+; HRMS (ES+): m/z [M+
H]+ calcd for C22H21N4O: 357.1710, found: 357.1717; Anal. calcd for
C22H20N4O: C 74.14, H 5.66, N 15.72, found: C 74.2, H 5.61, N 15.7.
(E)-(4-Benzyloxybenzyl)-(3,5-difluorophenyl)amine (21b): NaBH4
(1.0 g, 26.3 mmol) was added to a cooled (08C) suspension of 21a
(3.52 g, 10.89 mmol) in THF (20 mL) and EtOH (20 mL). The mixture
was allowed to warm to room temperature and stirring was contin-
ued for 18 h. The mixture was poured into H2O (100 mL) and ex-
tracted with EtOAc (3ꢃ50 mL). The combined organic fractions
were washed with H2O (50 mL) and brine (50 mL), dried (Na2SO4)
and concentrated under reduced pressure. The residue was puri-
fied by flash column chromatography (EtOAc) to afford the title
compound as a white solid (3.37 g, 95%): mp: 79–808C; 1H NMR
(400 MHz, [D6]DMSO): d=4.20 (2H s, CH2), 5.07 (2H, s, CH2), 6.20–
6.28 (3H, m, ArH), 6.96 (2H, AA’BB’, ArH), 7.25 (2H, AA’BB’, ArH),
7.32–7.45 ppm (5H, m, ArH); 13C NMR (100 MHz, [D6]DMSO): d=
47.5 (CH2), 70.1 (CH2), 92.5 (t, CH), 95.4 (2ꢃCH, m), 115.1 (2ꢃCH),
127.4 (2ꢃCH), 128.0 (CH), 128.6 (2ꢃCH), 128.8 (2ꢃCH), 130.4 (C)
136.9 (C), 150.2 (C, t), 158.3 (C), 163.5 ppm (2ꢃC, dd); HRMS (EI):
m/z [M]+ calcd for C20H17F2NO: 325.1273, found: 325.1276; Anal.
calcd for C20H17F2NO: C 73.83, H 5.27, N 4.31, found: C 73.8, H 5.26,
N 4.15.
4-{[Phenyl(4H-1,2,4-triazol-4-yl)amino]methyl}phenol (20e): As
general method A using 5% Pd/C (0.10 g), 20d (1.36 g, 3.80 mmol)
and THF/MeOH (1:1, 40 mL). The crude product was purified using
the CombiFlash system (CHCl3/acetone) to give the title compound
N-(4-Benzyloxybenzyl)-N-(3,5-difluorophenyl)hydrazine (21c): A
solution of NaNO2 (1.04 g, 15 mmol) in H2O (10 mL) was slowly
added to a cooled (08C) intensively stirred mixture of 21b (3.25 g,
10.0 mmol), CHCl3 (50 mL) and 2m H2SO4 (20 mL). The mixture was
stirred for 1 h and then the organic layer was separated, washed
with brine (20 mL), dried (Na2SO4) and concentrated in vacuo. The
residue was dissolved in THF (20 mL) and added to a suspension
of LiAlH4 (0.25 g) in THF (30 mL). The reaction mixture was stirred
overnight at room temperature, then H2O (2 mL) and 5m NaOH
(3 mL) were added carefully. The inorganic salts were filtered off
and washed with THF, the organic fraction was dried over Na2SO4
and the volatiles were removed in vacuo. The residue was purified
by flash column chromatography (CHCl3) to afford the title com-
pound as a white solid (2.45 g, 72%): mp: 94–968C; 1H NMR
(400 MHz, CDCl3): d=3.57 (2H, brs, NH2), 4.56 (2H, s, CH2), 5.15
(2H, s, CH2), 6.28–6.34 (1H, m, ArH), 6.69–6.74 (2H, m, ArH), 7.07
(2H, AA’BB’, ArH), 7.27 (2H, AA’BB’, ArH), 7.42–7.56 ppm (5H, m,
ArH); 13C NMR (100 MHz, [D6]DMSO): d=58.2 (CH2), 69.9 (CH2), 92.6
1
as a white solid (0.74 g, 74%): mp: 191–1938C; H NMR (400 MHz,
[D6]DMSO): d=4.78 (2H, s, CH2), 6.65 (2H, AA’BB’, ArH), 6.72–6.76
(2H, m, ArH), 6.97–7.02 (1H, m, ArH), 7.07 (2H, AA’BB’, ArH), 7.28–
7.34 (2H, m, ArH), 8.67 (2H, s, 2ꢃCHN), 9.43 ppm (1H, s, OH);
13C NMR (100 MHz, [D6]DMSO): d=57.3 (CH2), 114.7 (2ꢃCH), 115.2
(2ꢃCH), 122.0 (CH), 125.2 (C), 129.4 (2ꢃCH), 130.1 (2ꢃCH), 143.4
(2ꢃCH), 148.9 (C), 157.0 ppm (C); LRMS (ES+): m/z (%): 266.8 (100)
[M+H]+; HRMS (ES+): m/z [M+H]+ calcd for C15H15N4O: 267.1240,
found: 267.1240; Anal. calcd for C15H14N4O: C 67.65, H 5.30, N
21.04, found: C 67.5, H 5.16, N, 21.2.
4-{[Phenyl(4H-1,2,4-triazol-4-yl)amino]methyl}phenyl sulfamate
(20): As general method B using ClSO2NH2 (0.63m, 5.0 mL), DMA
(5 mL) and 20e (0.266 g, 1.00 mmol). The title compound (0.093 g,
27%) was obtained as a light-yellow solid which was recrystallised
from a small amount of acetone/hexane to give colourless crystals
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(t, CH), 95.8 (2ꢃCH, m), 115.1 (2ꢃCH), 127.4 (2ꢃCH), 127.9 (CH),
128.3 (C), 128.5 (2ꢃCH), 128.9 (2ꢃCH), 136.7 (C), 153.7 (C, t), 158.3
(C), 163.8 ppm (2ꢃC, dd); LRMS (ESꢀ): m/z (%): 339.4 (100) [MꢀH]ꢀ;
HRMS (ES+): m/z [M+H]+ calcd for C20H19F2N2O: 341.1460, found
341.1452; Anal. calcd for C20H18F2N2O: C 70.58, H 5.33, N 8.23,
found: C 70.7, H 5.32, N 8.29.
(E)-(4-Benzyloxybenzylidene)-(2,2-difluorobenzo[1,3]dioxol-5-yl)-
amine (22a): A mixture of 5-amino-2,2-difluoro-1,3-benzodioxole
(2.60 g, 15 mmol), 4-benzyloxybenzaldehyde (3.18 g, 15 mmol) and
p-TsOH·H2O (0.10 g) in EtOH (50 mL) was heated at reflux for 1 h.
The reaction mixture was allowed to cool to room temperature
and the crystals that formed were collected, washed with EtOH
and dried under high vacuum to afford the title compound as col-
ourless plates (4.30 g, 78%): mp: 114–1168C; 1H NMR (400 MHz,
CDCl3): d=5.20 (2H, s, CH2), 6.90 (1H, dd, J=8.6, 2.4 Hz, ArH), 6.96
(1H, d, J=2.4 Hz, ArH), 7.02–7–08 (3H, m, ArH), 7.33–7.46 (5H, m,
ArH), 7.83 (2H, AA’BB’, ArH), 8.33 ppm (1H, CH); 13C NMR (100 MHz,
CDCl3): d=70.1 (CH2), 102.7 (C), 109.5 (CH), 115.1 (2ꢃCH), 116.2
(CH), 127.5 (2ꢃCH), 128.2 (CH), 128.7 (2ꢃCH), 129.0 (C), 130.6 (2ꢃ
(4-Benzyloxybenzyl)-(3,5-difluorophenyl)-[1,2,4]triazol-4-ylamine
(21d): Dimethylformamide diazine dihydrochloride (2.15 g,
10.0 mmol) was added to a solution of 21c (1.70 g, 5.0 mmol) in
pyridine (5 mL) and the mixture was heated at reflux for 2 h. After
cooling to room temperature EtOAc (60 mL) and H2O (30 mL) were
added, the organic layer was separated, washed with 2m KHSO4
solution (2ꢃ30 mL) and brine (30 mL), dried (Na2SO4) and concen-
trated under reduced pressure. The residue was purified by flash
column chromatography (CHCl3/acetone) to afford the title com-
pound (1.37 g, 70%) as a colourless solid, which recrystallised from
1
CH), 131.8 (C, t, JC-F =255 Hz), 136.3 (C), 141.6 (C), 144.2 (C), 148.6
(C), 159.8 (CH), 161.6 ppm (C); 19F NMR (376.4 MHz, CDCl3): d=
ꢀ49.8 ppm (s); LRMS (ES+): m/z (%): 368.4 (100) [M+H]+; HRMS
(ES+): m/z [M+H]+ calcd for C21H15F2NO3: 368.1093, found:
368.1099; Anal. calcd for C21H15F2NO3: C 68.66, H 4.12, N 3.81,
found: C 68.6, H 4.11, N 3.70.
1
CHCl3/hexane to give pale-yellow plates: mp: 142–1438C; H NMR
(400 MHz, CDCl3): d=4.68 (2H, s, CH2), 5.01 (2H, s, CH2), 6.16–6.20
(2H, m, ArH), 6.43–6.49 (1H, m, ArH), 6.90 (2H, AA’BB’, ArH), 7.07
(2H, AA’BB’, ArH), 7.31–7.42 (5H, m, ArH), 8.03 ppm (2H, s, 2ꢃ
CHN); 13C NMR (100 MHz, [D6]DMSO): d=57.9 (CH2), 70.0 (CH2), 97.5
(m, CH, 2ꢃCH), 115.4 (2ꢃCH), 125.5 (C), 127.5 (2ꢃCH), 128.1 (CH),
128.6 (2ꢃCH), 129.8 (2ꢃCH), 136.4 (C), 142.6 (2ꢃCH), 149.8 (C, t),
159.2 (C), 163.8 (2ꢃC, dd); 19F NMR (376.4 MHz, [D6]DMSO): d=
ꢀ106.8 ppm (m); LRMS (ESꢀ): m/z (%): 391.3 (10) [MꢀH]ꢀ; HRMS
(ES+): m/z [M+H]+ calcd for C22H19F2N4O: 393.1521, found:
393.1526; Anal. calcd for C22H18F2N4O: C 67.34, H 4.62, N 14.28,
found: C 67.2, H 4.74, N 14.2.
(4-Benzyloxybenzyl)-(2,2-difluorobenzo[1,3]dioxol-5-yl)amine
(22b): NaBH4 (1.0 g, 26.3 mmol) was added to a cooled (08C) sus-
pension of 22a (4.02 g, 10.94 mmol) in THF (20 mL) and EtOH
(20 mL). The mixture was allowed to warm to room temperature
and stirring was continued for 18 h. The mixture was poured into
H2O (100 mL) and extracted with EtOAc (3ꢃ50 mL). The combined
organic fractions were washed with H2O (50 mL) and brine (50 mL),
dried (Na2SO4) and concentrated under reduced pressure. The resi-
due was purified by flash column chromatography (EtOAc) to
afford the title compound as a white solid (3.89 g, 96%): mp: 63–
648C; 1H NMR (400 MHz, CDCl3): d=3.97 (1H, s, NH), 4.19 (2H, s,
CH2), 5.06 (2H, s, CH2), 6.24 (1H, dd, J=8.6, 2.3 Hz, ArH), 6.36 (1H,
d, J=2.3 Hz, ArH), 6.83 (1H, d, J=8.6 Hz, ArH), 6.96 (2H, AA’BB’,
ArH), 7.26 (2H, AA’BB’, ArH), 7.30–7.45 ppm (5H, m, ArH); 13C NMR
(100 MHz, CDCl3): d=48.3 (CH2), 70.0 (CH2), 95.3 (CH), 106.5 (CH),
109.7 (CH), 115.0 (2ꢃCH), 127.4 (2ꢃCH), 128.0 (CH), 128.6 (2ꢃCH),
4-{[(3,5-Difluorophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}phe-
nol (21e): As general method A using 5% Pd/C (0.10 g), 21d (1.02,
2.60 mmol) and THF/MeOH (1:1, 40 mL). The crude product was
dissolved in acetone and Et2O was added. The precipitate was fil-
tered off and dried under high vacuum to afford the title com-
pound as a white solid (0.668 g, 85%): mp: 214–2178C; 1H NMR
(400 MHz, [D6]DMSO): d=4.83 (2H, s, CH2), 6.36 (2H, s, ArH), 6.65
(2H, AA’BB’, ArH), 6.80–6.87 (1H, m, ArH), 7.03 (2H, AA’BB’, ArH),
8.67 (2H, s, 2ꢃCHN), 9.49 ppm (1H, s, OH); 13C NMR (100 MHz,
[D6]DMSO): d=57.0 (CH2), 96.5 (t, CH), 97.7 (m, 2ꢃCH), 115.3 (2ꢃ
CH), 124.4 (C), 130.3 (2ꢃCH), 143.4 (2ꢃCH), 151.2 (C, t), 159.2 (C),
163.3 ppm (2ꢃC, dd); 19F NMR (376.4 MHz, [D6]DMSO): d=
ꢀ108.4 ppm (m); LRMS (ES+): m/z (%): 303.4 (100) [M+H]+; HRMS
(ES+): m/z [M+H]+ calcd for C15H13F2N4O: 303.1052, found:
303.1058; Anal. calcd for C15H12F2N4O: C 59.90, H 4.00, N 18.53,
found: C 59.4, H 4.14, N 18.7.
1
128.7 (2ꢃCH), 130.9 (C), 131.7 (C, t, JC-F =253 Hz), 135.8 (C), 136.9
(C), 144.6 (C), 145.2 (C), 158.2 ppm (C); LRMS (APCIꢀ): m/z (%):
368.4 (100) [MꢀH]ꢀ; HRMS (ES+): m/z [M+Na]+ calcd for
C21H17F2NO3Na: 392.1069, found: 392.1065; Anal. calcd for
C21H17F2NO3: C 68.29, H 4.64, N 3.79, found: C 68.3, H 4.63, N, 3.62.
N-(4-Benzyloxybenzyl)-N-(2,2-difluorobenzo[1,3]dioxol-5-yl)hy-
drazine (22c): A solution of NaNO2 (1.04 g, 15 mmol) in H2O
(10 mL) was slowly added to a cooled (08C) intensively stirred mix-
ture of 22b (3.69 g, 10.0 mmol), CHCl3 (50 mL) and 2m H2SO4
(20 mL). The mixture was stirred for 1 h and then the organic layer
was separated, washed with brine (20 mL), dried (Na2SO4) and con-
centrated in vacuo. The residue was dissolved in THF (20 mL) and
added to a suspension of LiAlH4 (0.25 g) in THF (30 mL). The reac-
tion mixture was stirred overnight at room temperature, then H2O
(2 mL) and 5m NaOH (3 mL) were added carefully. The inorganic
salts were filtered off and washed with THF, the organic fraction
was dried over Na2SO4 and the volatiles were removed in vacuo.
The residue was purified by flash column chromatography (CHCl3)
to afford the title compound as a white solid (2.88 g, 75%): mp:
80–818C; 1H NMR (400 MHz, [D6]DMSO): d=3.50 (2H, brs, NH2),
4.43 (2H, s, CH2), 5.06 (2H, s, CH2), 6.71 (1H, dd, J=8.6, 2.3 Hz,
ArH), 6.89 (1H, d, J=8.6 Hz, ArH), 6.95 (2H, AA’BB’, ArH), 6.99 (1H,
d, J=2.3 Hz, ArH), 7.18 (2H, AA’BB’, ArH), 7.30–7.45 ppm (5H, m,
ArH); 13C NMR (100 MHz, [D6]DMSO): d=60.7 (CH2), 70.0 (CH2), 97.7
4-{[(3,5-Difluorophenyl)(4H-1,2,4-triazol-4-yl)amino]methyl}phen-
yl sulfamate (21): As general method B using ClSO2NH2 (0.65m,
5.0 mL), DMA (5 mL) and 21e (0.302 g, 1.00 mmol). The crude
product was recrystallised from a small amount of acetone to
afford the title compound as colourless crystals (0.143 g, 37%):
mp: 178–1808C; 1H NMR (400 MHz, [D6]DMSO): d=5.03 (2H, s,
CH2), 6.35–6.45 (2H, m, ArH), 6.82–6.90 (1H, m, ArH), 7.23 (2H,
AA’BB’, ArH), 7.39 (2H, AA’BB’, ArH), 8.05 (2H, s, NH2), 8.81 (2H, s,
2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO): d=57.0 (CH2), 96.8 (t, CH),
97.6 (m, 2ꢃCH), 122.3 (2ꢃCH), 130.0 (2ꢃCH), 133.2 (C), 143.3 (2ꢃ
CH), 149.9 (C), 151.0 (C, t), 163.3 ppm (2ꢃC, dd); 19F NMR
(376.4 MHz, [D6]DMSO): d=ꢀ108.2 ppm (m); LRMS (ESꢀ): m/z (%):
380.2 (100) [MꢀH]ꢀ; HRMS (ES+): m/z [M+H]+ calcd for
C15H14F2N5O3S: 382.0780, found: 382.0789; Anal. calcd for
C15H13F2N5O3S: C 47.24, H 3.44, N 18.36, found: C 47.2, H 3.42, N
18.6.
(CH), 108.1 (CH), 109.1 (CH), 115.1 (2ꢃCH), 127.5 (2ꢃCH), 128.0
1
(CH), 128.5 (C), 128.6 (2ꢃCH), 129.4 (2ꢃCH), 131.8 (C, t, JCF
=
253 Hz), 136.7 (C), 136.8 (C), 144.5 (C), 149.0 (C), 158.4 ppm (C);
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HRMS (ES+): m/z [M+H]+ calcd for C21H19F2N2O3: 385.1358, found:
385.1361; Anal. calcd for C21H18F2N2O3: C 65.62, H 4.72, N 7.29,
found: C 65.4, H 4.72, N 7.37.
4-(2-Thioxo-2,3-dihydro-1H-imidazol-1-ylamino)benzonitrile (23):
A
mixture of 4-cyanophenylhydrazine hydrochloride (5.00 g,
29.48 mmol), 2-isothiocyanato-1,1-dimethoxyethane (5.0 g,
33.97 mmol) in AcOH (50 mL) and H2O (5 mL) was heated at 1008C
for 1 hour. The mixture was poured into H2O (300 mL) after cooling
to room temperature. The precipitate was collected by filtration,
washed with H2O and dried under high vacuum to afford 23 as
a yellow powder (5.12 g, 80%): mp:>2508C; 1H NMR (400 MHz,
[D6]DMSO): d=6.55 (AA’BB’, 2H), 7.02 (t, J=2.3 Hz, 1H), 7.24 (t, J=
2.3 Hz, 1H), 7.63 (AA’BB’, 2H), 9.87 (s, 1H), 12.45 ppm (s, 1H);
13C NMR (100.6 MHz, [D6]DMSO): d=100.8, 112.6, 113.8, 119.7,
120.3, 133.6, 151.0, 162.3 ppm; LRMS (ES+): m/z (%): 216.6 (100)
[M+H]+); HRMS (ES+): m/z [M+H]+ calcd for C10H9N4S: 217.0542,
found: 217.0541; Anal. calcd for C10H8N4S: C 55.54, H 3.73, N 25.91,
found: C 55.3, H 3.58, N 25.9.
(4-Benzyloxybenzyl)-(2,2-difluorobenzo[1,3]dioxol-5-yl)-[1,2,4]tri-
azol-4-ylamine (22d): Dimethylformamide diazine dihydrochloride
(2.47 g, 11.5 mmol) was added to a solution of 22c (2.21 g,
5.75 mmol) in pyridine (5 mL) and the mixture was heated at reflux
for 2 h. After cooling to room temperature EtOAc (60 mL) and H2O
(30 mL) were added, the organic layer was separated, washed with
2m KHSO4 solution (2ꢃ30 mL) and brine (30 mL), dried (Na2SO4)
and concentrated under reduced pressure. The residue was puri-
fied by flash column chromatography (CHCl3/acetone) to afford the
title compound as a colourless solid, which recrystallised from
CHCl3/hexane to give colourless plates (1.41 g, 56%): mp: 112–
1
114 8C; H NMR (400 MHz, CDCl3): d=4.63 (2H, s, CH2), 4.99 (2H, s,
4-(1H-Imidazol-1-ylamino)benzonitrile (24): To a suspension of 23
(2.99 g, 13.83 mmol) in AcOH (10 mL) was added 50% H2O2
(2.0 mL) slowly via syringe (exothermic reaction) with ice cooling.
The resulting clear red-brown solution was stirred for 0.5 h before
it was diluted with H2O (10 mL), neutralised with 5m NaOH and
treated with 1m NaSO3 (5 mL). The mixture was extracted with
EtOAc (3ꢃ30 mL), the combined extracts were dried (Na2SO4) and
concentrated under reduced pressure. The residue was purified by
chromatography (ISCO CombiFlash; gradient: CH2Cl2 to CH2Cl2/
MeOH (90:10), 40 g SiO2 column) to give crude 24 as an orange
solid. The solid was dissolved in EtOAc and treated with activated
charcoal. The charcoal was removed by filtration and the volatiles
were removed under reduced pressure. The residue was recrystal-
lised from EtOAc/hexane to afford 24 as a light-yellow solid
CH2), 6.47 (1H, dd, J=9.0, 2.7 Hz, ArH), 6.57 (1H, d, J=2.7 Hz, ArH),
6.89 (2H, AA’BB’, ArH), 6.96 (1H, d, J=9.0 Hz, ArH), 7.08 (2H,
AA’BB’, ArH), 7.31–7.41 (5H, m, ArH), 8.06 ppm (2H, s, 2ꢃCHN);
13C NMR (100 MHz, CDCl3): d=59.0 (CH2), 69.9 (CH2), 99.0 (CH),
109.8 (CH), 110.3 (CH), 115.2 (2ꢃCH), 125.8 (C), 127.4 (2ꢃCH), 128.0
(CH), 128.5 (2ꢃCH), 129.9 (2ꢃCH), 131.6 (C, t), 136.4 (C), 139.5 (C),
142.4 (2ꢃCH), 144.5 (C), 144.6 (C), 159.0 ppm (C); LRMS (ESꢀ): m/z
(%): 435.5 (100) [MꢀH]ꢀ; HRMS (ES+): m/z [M+H]+ calcd for
C23H19F2N4O3: 437.1420, found: 437.1420; Anal. calcd for
C23H18F2N4O3: C 63.30, H 4.16, N 12.84, found: C 63.0, H 4.19, N
12.9.
4-{[(2,2-Difluorobenzo[1,3]dioxol-5-yl)-[1,2,4]triazol-4-ylamino]-
methyl}phenol (22e): As general method A using 5% Pd/C
(0.10 g), 22d (1.20, 2.76 mmol) and THF/MeOH (1:1, 40 mL). The
crude product was recrystallised from acetone/Et2O to afford the
title compound (0.88 g, 92%) as a white solid; mp: 182–1858C;
1H NMR (400 MHz, [D6]DMSO): d=4.75 (2H, s, CH2), 6.48 (1H, dd,
J=8.6, 2.4 Hz, ArH), 6.65 (2H, AA’BB’, ArH), 7.04 (2H, AA’BB’, ArH),
7.16 (1H, d, J=2.4 Hz, ArH), 7.35 (1H, d, J=8.6 Hz, ArH), 8.67 (2H,
s, 2ꢃCHN), 9.47 ppm (1H, s, OH); 13C NMR (100 MHz, [D6]DMSO):
d=58.0 (CH2), 99.5 (CH), 110.5 (CH), 111.2 (CH), 115.3 (2ꢃCH), 124.8
(C), 130.3 (2ꢃCH), 131.4 (C, t), 138.1 (C), 143.2 (2ꢃCH), 143.5 (C),
146.0 (C), 157.2 ppm (C); 19F NMR (376.4 MHz, [D6]DMSO): d=
ꢀ49.1 ppm (s); LRMS (ES+): m/z (%): 369.3 (55) [M+Na]+, 347.3
(20) [M+H]+, 278.2 (100); HRMS (ES+): m/z [M+H]+ calcd for
C16H13F2N4O3: 347.0950, found: 347.0959; Anal. calcd for
C16H12F2N4O3: C 55.49, H 3.49, N, 16.18, found: C 55.5, H 3.49, N
16.4.
1
(1.501 g, 59%): mp: 157–1598C; H NMR (400 MHz, [D6]DMSO): d=
6.49 (AA’BB’, 2H), 7.06 (t, J=1.2 Hz, 1H), 7.33 (t, J=1.2 Hz, 1H),
7.65 (AA’BB’, 2H), 7.82 (s, 1H), 10.11 ppm (s, 1H); 13C NMR
(100.6 MHz, [D6]DMSO): d=104.4, 112.0, 119.5, 120.7, 128.0, 134.0,
137.6, 151.9 ppm; LRMS (ES+): m/z (%): 184.6 (100) [M+H]+;
HRMS (ES+): m/z [M+H]+ calcd for C10H9N4O: 185.0822, found:
185.0819.
[4-(Benzyloxy)-2-fluorophenyl]methanol (25a): A mixture of 11 b
(0.85 g, 5.98 mmol), benzyl bromide (1.13 g, 6.58 mmol), K2CO3
(5.00 g, 36.23 mmol) and DMF (20 mL) was stirred intensively for
48 h. The mixture was poured into H2O (100 mL) and the product
was extracted with EtOAc (3ꢃ50 mL). The organic layers were
dried (MgSO4) and concentrated in vacuo. The residue was purified
using the CombiFlash Rf (EtOAc/PE) to afford the title compound
as a colourless oil which solidified upon standing (1.17 g, 84%):
1
mp: 67–688C; H NMR (400 MHz, CDCl3): d=1.78 (1H, t, J=6.1 Hz,
OH), 4.67 (2H, d, J=6.1 Hz, CH2), 5.05 (2H, s, CH2), 6.68–6.79 (2H,
m, ArH), 7.25–7.45 ppm (6H, m, ArH); LRMS (ES+): m/z (%): 214.8
(100) [MꢀOH]+.
4-{[(2,2-Difluorobenzo[d][1,3]dioxol-5-yl)(4H-1,2,4-triazol-4-yl)a-
mino]methyl}phenyl sulfamate (22): As general method B using
ClSO2NH2 (0.65m, 5.0 mL), DMA (5 mL) and 22e (0.35 g,
1.00 mmol). The crude product was purified by flash column chro-
matography (CHCl3/acetone) to afford the title compound as
a white solid (0.32 g, 75%): mp: 132–1348C; 1H NMR (400 MHz,
[D6]DMSO): d=4.94 (2H, s, CH2), 6.50 (1H, dd, J=9.0, 2.5 Hz, ArH),
7.17 (1H, d, J=2.5 Hz, ArH), 7.21 (2H, AA’BB’, ArH), 7.35 (1H, d, J=
9.0 Hz, ArH), 7.40 (2H, AA’BB’, ArH), 8.04 (2H, s, NH2), 8.81 ppm
(2H, s, 2ꢃCHN); 13C NMR (100 MHz, [D6]DMSO): d=57.9 CH2), 99.6
(CH), 110.6 (CH), 111.3 (CH), 122.2 (2ꢃCH), 130.0 (2ꢃCH), 131.4 (C,
t), 133.4 (C), 138.3 (C), 143.1 (2ꢃCH), 143.6 (C), 145.8 (C),
149.8 ppm (C); 19F NMR (376.4 MHz, [D6]DMSO): d=ꢀ49.1 ppm (s);
LRMS (ESꢀ): m/z (%): 424.4 (100) [MꢀH]ꢀ; HRMS (ES+): m/z [M+
H]+ calcd for C16H14F2N5O5S: 426.0678, found: 426.0686; Anal. calcd
for C16H13F2N5O5S: C 45.18, H 3.08, N 16.46, found: C 45.0, H 3.10, N
16.5.
4-(Benzyloxy)-1-(chloromethyl)-2-fluorobenzene (25b): SOCl2
(1.0 mL) was added to a solution of 25a (1.12 g, 4.82 mmol) in
CH2Cl2 (20 mL) and the resulting solution was stirred for 2 h. Then
H2O (10 mL) was added, the organic layer was separated, washed
with brine (10 mL), dried (MgSO4) and concentrated in vacuo. The
residue was purified using the CombiFlash Rf (EtOAc/PE) to afford
the title compound as a colourless oil (1.02 g, 85%): 1H NMR
(400 MHz, [D6]DMSO): d=4.60 (2H, s, CH2), 5.05 (2H, s, CH2), 6.67–
6.77 (2H, m, ArH), 7.30–7.43 ppm (6H, m, ArH); LRMS (ES+): m/z
(%): 250.7 (100) [M+H]+.
4-{[4-(Benzyloxy)-2-fluorobenzyl](1H-imidazol-1-yl)amino}benzo-
nitrile (25c): NaH (60% dispersion in mineral oil, 0.12 g, 3.0 mmol)
was added to a solution of 24 (0.55 g, 3.0 mmol) in DMF (10 mL).
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www.chemmedchem.org
[5] B. Apsel, J. A. Blair, B. Gonzalez, T. M. Nazif, M. E. Feldman, B. Aizenstein,
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After stirring the mixture for 0.5 h, 25b (0.75 g, 3.0 mmol) was
added and stirring was continued for 18 h. The reaction mixture
was diluted with EtOAc (60 mL), washed with H2O (3ꢃ30 mL) and
brine (30 mL), dried (Na2SO4) and concentrated in vacuo. The resi-
due was purified using the CombiFlash Rf (EtOAc/PE) to afford an
orange solid, which was recrystallised from EtOAc/PE to give the
title compound as colourless crystals (1.01 g, 85%): mp: 132–
1348C; 1H NMR (400 MHz, [D6]DMSO): d=4.99 (2H, s, CH2), 5.08
(2H, s, CH2), 6.69 (2H, AA’BB’, ArH), 6.77 (1H, dd, J=8.4, 2.3 Hz,
ArH), 6.91 (1H, dd, J=8.4, 2.4 Hz, ArH), 6.98 (1H, s, ArH), 7.19 (1H,
t, J=8.6 Hz, ArH), 7.31 (1H, s, ArH), 7.33–7.45 (5H, m, ArH), 7.64
(1H, s, ArH), 7.72 ppm (2H, AA’BB’, ArH); LRMS (ES+): m/z (%):
398.9 (100) [M+H]+; HRMS (ES+): m/z [M+H]+ calcd for
C24H19FN4O: 399.1616, found: 399.1614.
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4-[(2-Fluoro-4-hydroxybenzyl)(1H-imidazol-1-yl)amino]benzoni-
trile (25d): As general method A using 5% Pd/C (0.10 g), 25c
(0.797 g, 2.0 mmol) and THF/MeOH (1:1, 40 mL). The crude product
was purified using the CombiFlash Rf (CH2Cl2/MeOH) to give the
title compound as a white solid (0.50 g, 81%): mp: 192–1948C;
1H NMR (400 MHz, [D6]DMSO): d=4.92 (2H, s, CH2), 6.45–6.56 (2H,
m, ArH), 6.69 (2H, AA’BB’, ArH), 6.97 (1H, s, ArH), 7.03 (1H, t, J=
8.6 Hz, ArH), 7.28 (1H, s, ArH), 7.60 (1H, s, ArH), 7.75 (2H, AA’BB’,
ArH), 9.99 ppm (1H, s, OH); 13C NMR (100 MHz, [D6]DMSO): d=50.4
(CH2), 101.9 (C), 102.5 (CH, d), 111.5 (CH), 111.7 (C), 111.8 (C), 113.2
(2ꢃCH), 119.2 (C), 128.0 (CH), 131.7 (CH, d), 133.7 (2ꢃCH), 137.1
(CH), 152.0 (C), 159.1 (C), 161.0 ppm (C, d); 19F NMR (376 MHz,
[D6]DMSO): d=ꢀ116.2 ppm (t); LC–MS (ES+): tR =1.24 min, m/z
(%): 309.0 (100) [M+H]+.
4-{[(4-cyanophenyl)(1H-imidazol-1-yl)amino]methyl}-3-fluoro-
phenyl sulfamate (25): As general method B using ClSO2NH2
(0.6m, 5.0 mL), DMA (2 mL) and 25d (0.20 g, 0.65 mmol). The crude
product was purified using the CombiFlash system (CHCl3/acetone)
to give the title compound as a white powder (0.21 g, 88%):
1H NMR (400 MHz, [D6]DMSO): d=5.08 (2H, s, CH2), 6.65 (2H,
AA’BB’, ArH), 6.99 (1H, s, ArH), 7.02 (1H, dd, J=8.4, 2.0 Hz, ArH),
7.14 (1H, dd, J=10.8, 2.0 Hz, ArH), 7.35 (1H, s, ArH), 7.42 (1H, t, J=
8.4 Hz, ArH), 7.67–7.73 (3H, m, ArH), 8.10 ppm (2H, s, 2ꢃCHN);
13C NMR (100 MHz, [D6]DMSO): d=50.7 (CH2), 102.2 (C), 109.7 (CH),
113.1 (2ꢃCH), 118.0 (CH), 119.1 (C), 119.2 (CH), 120.6 (C, d), 128.1
(CH), 131.4 (CH), 133.8 (2ꢃCH), 137.2 (CH), 150.6 (C), 151.9 (C),
160.3 ppm (C, d); LC–MS (ES+): tR =1.10 min, m/z (%): 388.2 (100)
[M+H]+; HRMS (ES+): m/z [M+H]+ calcd for C17H15FN5O3S:
388.0874, found: 388.0847.
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Acknowledgements
This work was supported by Sterix Ltd., a member of the Ipsen
group, and by the Wellcome Trust, VIP funding and Programme
Grant 082837. We thank Ms. Alison C. Smith (Bath) for technical
assistance.
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Potter, ChemMedChem 2011, 6, 1423–1438.
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Keywords: aromatase · breast cancer · dual inhibitors
endocrine therapy · steroid sulfatase
·
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