Identification of potent, selective and orally bioavailable phenyl ((R)-3-phenylpyrrolidin-3-yl)sulfone analogues as RORγt inverse agonists

Article abstract of DOI:10.1016/j.bmcl.2019.06.036

An X-ray crystal structure of one of our previously discovered RORγt inverse agonists bound to the RORγt ligand binding domain revealed that the cyclohexane carboxylic acid group of compound 2 plays a significant role in RORγt binding, forming four hydrog

Full text of DOI:10.1016/j.bmcl.2019.06.036

Accepted Manuscript
Identification of potent, selective and orally bioavailable phenyl ((R)-3-phenyl-
pyrrolidin-3-yl)sulfone analogues as RORγt inverse agonists
Zhonghui Lu, James J.-W. Duan, Haiyun Xiao, James Neels, Dauh-Rurng Wu,
Carolyn A. Weigelt, John S. Sack, Javed Khan, Max Ruzanov, Yongmi An,
Melissa Yarde, Ananta Karmakar, Sureshbabu Vishwakrishnan, Venkata
Baratam, Harisha Shankarappa, Sridhar Vanteru, Venkatesh Babu, Mushkin
Basha, Arun Kumar Gupta, Selvakumar Kumaravel, Arvind Mathur, Qihong
Zhao, Luisa M. Salter-Cid, Percy H. Carter, T.G. Murali Dhar
PII:
S0960-894X(19)30416-0
https://doi.org/10.1016/j.bmcl.2019.06.036
BMCL 26514
DOI:
Reference:
Bioorganic & Medicinal Chemistry Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
11 April 2019
11 June 2019
19 June 2019
Please cite this article as: Lu, Z., Duan, J.J., Xiao, H., Neels, J., Wu, D-R., Weigelt, C.A., Sack, J.S., Khan, J.,
Ruzanov, M., An, Y., Yarde, M., Karmakar, A., Vishwakrishnan, S., Baratam, V., Shankarappa, H., Vanteru, S.,
Babu, V., Basha, M., Kumar Gupta, A., Kumaravel, S., Mathur, A., Zhao, Q., Salter-Cid, L.M., Carter, P.H., Murali
Dhar, T.G., Identification of potent, selective and orally bioavailable phenyl ((R)-3-phenylpyrrolidin-3-yl)sulfone
analogues as RORγt inverse agonists, Bioorganic & Medicinal Chemistry Letters (2019), doi: https://doi.org/
10.1016/j.bmcl.2019.06.036
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com
Identification of potent, selective and orally bioavailable phenyl
((R)-3-phenylpyrrolidin-3-yl)sulfone analogues as RORt inverse agonists
Zhonghui Lu*a, James J.-W. Duan*a, Haiyun Xiaoa, James Neelsa, Dauh-Rurng Wua, Carolyn A. Weigelta,
John S. Sacka, Javed Khana, Max Ruzanova, Yongmi Ana, Melissa Yardea, Ananta Karmakarb, Sureshbabu
Vishwakrishnanb, Venkata Baratamb, Harisha Shankarappab, Sridhar Vanterub, Venkatesh Babub, Mushkin
Bashab, Arun Kumar Guptab, Selvakumar Kumaravelb, Arvind Mathura, Qihong Zhaoa, Luisa M. Salter-
Cida, Percy H. Cartera and T. G. Murali Dhara
a Research and Development, Bristol-Myers Squibb Company, Princeton, New Jersey 08543-4000, United States.
b Bristol-Myers Squibb-Biocon Research Center, Bangalore, India.
 Corresponding authors. E-mails: zhonghui.lu@bms.com, james.duan@bms.com
ARTICLE INFO
ABSTRACT
Article history:
Received
Revised
Accepted
Available online
An X-ray crystal of one of our previously discovered RORt
inverse agonists bound to the RORt ligand binding domain
revealed that the cyclohexane carboxylic acid group of
compound 2 plays a significant role in RORt binding, forming
four hydrogen bonding and ionic interactions with RORt.
SAR studies centered around the cyclohexane carboxylic acid
group led to identification of several structurally diverse and
more potent compounds, including new carboxylic acid
analogues 7 and 20, and cyclic sulfone analogues 34 and 37.
Notably, compounds 7 and 20 were found to maintain the
desirable pharmacokinetic profile of 2.
Keywords:
RORt
Retinoic acid-related orphan
receptor gamma t
Inverse agonist
Th17
2019 Elsevier Ltd. All rights reserved.
IL-17
The retinoic acid-related orphan receptor (ROR) family of
nuclear receptors comprises three members: ROR, ROR and
ROR RORt being a splice variant of ROR.1 The three RORs
share a high degree of sequence similarity, but exhibit distinct
tissue distribution patterns and distinct functional roles in the
regulation of many physiological processes including
development, immunity, circadian rhythm and cellular
metabolism.2 RORt is the key transcription factor that drives
differentiation of naïve CD4+ T helper cells to Th17 cells, and
induces the transcription of IL-17A and IL-17F.3 There is
abundant evidence that the IL-17/Th17 pathway plays an
important role in the pathogenesis of psoriasis.4 Biologics known
to inhibit the IL-17/Th17 pathway are clinically validated for the
treatment of psoriasis.5 Targeting RORt also provides a novel
opportunity to treat other autoimmune diseases such as
inflammatory bowel disease (IBD), rheumatoid arthritis (RA) and
multiple sclerosis (MS).6 In addition, RORt-deficient mice show
significantly reduced Th17 cell populations and decreased
susceptibility to experimental autoimmune encephalomyelitis
(EAE) as well as intestinal and skin inflammation.1,7 Thus RORt
has garnered significant attention as a small molecule therapeutic
target.8-12
Our group recently reported the discovery of a series of
bicyclic sulfonamides as RORt inverse agonists.13
A
representative compound 1 (Figure 1) showed an EC50 of 39 nM
in the Jurkat cell-based Gal4 reporter assay for RORt. However,
it suffered from agonist activity against pregnant X receptor
(PXR) in vitro (EC50 = 2000 nM, Ymax = 100%) and cytochrome
P450 induction in vivo. We then described structure-based drug
design efforts that led to a novel phenyl (3-phenylpyrrolidin-3-
yl)sulfone series as exemplified by compound 2 (Figure 1).14
Compound 2 exhibited an EC50 of 119 nM in the RORt Gal4
reporter assay, no detectable activity against PXR and desirable
pharmacokinetic (PK) profiles in mouse. Furthermore, compound
2 displayed dose-dependent inhibition of IL-17 production in a
mouse IL-2/IL-23-induced pharmacodynamic model and
biologic-like efficacy in an IL-23-induced mouse acanthosis
model. This letter describes subsequent structure-activity
relationship (SAR) studies to improve the potency of compound
2.

F
O
acid, because of the potential liability of the carboxylic acid
group toward glucuronidation.
OH
O
O
N
CF3
S
N
F
R
O
H
N
Me
Me
F3C
OH
The effects of additional substitution to 1- and 4-position of
the cyclohexane ring ( to the carboxylic acid and the
carboxamide, respectively) are summarized in Table 1. The
trans-1-methyl cyclohexane carboxylic acid 3 was perhaps more
active than compound 2 (EC50 of 79 nM vs. 119 nM). However,
the trans-1-ethyl and 1-fluoro analogues (4 and 5) lost activity
approximately 2 and 5 fold, respectively, compared to 2.
Substitution at 4-position of the cyclohexane ring turned out to be
more fruitful. Alkyl-substituted trans-analogues (6-8) improved
potency by 2-4 fold compared to 2, with the ethyl derivative 7
being the most potent at 31 nM. The two ether compounds (9 and
10) were less potent compared to the alkyl analogues. Fluoro-
substitution (11) was tolerated, whereas the two hydroxy
analogues (12 and 13, cis or trans not assigned) were slightly less
potent than 2. Similar to previous observation14, cis-cyclohexane
carboxylic acids 14 and 15 showed much weaker activity
compared to their trans counterparts (5 and 6, respectively). This
could be explained by the fact that the cis-cyclohexanes in 14 and
15 cannot project the two carbonyl groups in the 1,4-di-equatorial
orientation as observed in the structure of compound 2/RORt
(Figure 2) and further demonstrated the importance of the di-
equatorial conformation for binding affinity. Overall, analogues
in Table 1 showed good selectivity against PXR and good liver
microsome stability. Additionally, all compounds in Table 1 (as
well as Tables 2 and 3) exhibited excellent selectivity against
ROR (>40 M), ROR (>40 M), LXR (>7.5 M) and
LXR (>7.5 M).
F
S
F
O
F3C
HO
O
O
1
2
CF3
RORt EC50 = 39 ± 18 nM
PXR EC50 = 2000 nM (100% max)
RORt EC50 = 119 ± 28 nM
PXR EC50 = >50000 nM (18% max)
Figure 1. Previously reported RORt inverse agonists.
Previous SAR studies14 of the phenyl (3-phenylpyrrolidin-3-
yl)sulfone scaffold revealed that the (R)-enantiomer of the
pyrrolidine was more potent than the (S)-enantiomer; the
perfluoroisopropyl and para-fluorophenyl groups were optimal
for balanced potency-selectivity profiles; and the trans-
cyclohexane stereochemistry in compound 2 provided greater
potency than the cis-isomer. To gain insights on how to improve
potency, an X-ray crystal structure of compound 2 with the
ligand binding domain (LBD) of RORt was solved (Figure 2).15
Compared to a previously disclosed structure of a related
analogue (compound 12 in ref. 14), the phenyl (3-
phenylpyrrolidin-3-yl)sulfone backbone of 2 adopted a similar
binding mode in RORt. The trans-cyclohexane ring adopted a
chair conformation, placing the two carbonyl groups in a 1,4-di-
equatorial arrangement. The terminal carboxylic acid moiety fits
nicely in a binding site surrounded by multiple polar amino acid
residues - forming four polar (hydrogen bonding and ionic)
interactions with backbone NH groups of Gln286 and Leu287
and guanidine side chains of Arg364 and Arg367.
SAR related to the replacement of the cyclohexane ring with
bicyclic scaffolds is outlined in Table 2. Three fused
bicyclo[3.1.0]hexane analogues (16-18) were synthesized and
were found to lose RORt activity compared to 2. Of the two
bridged analogues, the bicyclo[2.2.2]octane compound 20
showed EC50 of 33 nM in the RORt Gal4 reporter assay, while
the corresponding bicyclo[2.2.1]heptane analogue 19 was about
10-fold less potent (392 nM). Also noteworthy here is that
compound 20 maintained high selectivity against PXR and
displayed promising liver microsome stability. Two
oxabicyclo[2.2.2]octane analogues (21 and 22) were also
prepared. Unfortunately, both of them lost potency by several
fold compared to 20. The enhanced potency of 20 compared to 2
could be explained by the ability of bicyclo[2.2.2]octane ring, a
known bioisostere to the 1,4-trans-cyclohexane,16 to place the
two carbonyl groups in 180° arrangement, reminiscent of the 1,4-
diequatorial binding conformation of 2 (figure 2). The added
steric bulk of bicyclo[2.2.2]octane could also enhance binding to
RORt. In contrast, the bicyclo[2.2.1]heptane ring in 19 and the
bicyclo[3.1.0]hexanes in 16-18 cannot effectively achieve the
linear arrangement for the two carbonyl groups, thus leading to
reduced RORt potency.
Figure 2. X-ray crystal structure of compound 2 and the LBD of RORt
(PDB ID 6P9F). The carbons of the protein are colored in pink and those of 2
in green. Sulfurs are colored in yellow, nitrogens in blue, oxygens in red and
fluorines in cyan. Hydrogen bonds between compound 2 and RORt LBD are
indicated by a dashed line.
Our efforts to identify non-carboxylic acid alternatives are
summarized in Table 3. Compounds 23-31 were derived from
direct replacement of the carboxylic acid group with known
bioisosteres, while keeping the cyclohexane ring intact.
Compared to the acid 2, the tetrazole compound 23 showed
significant loss of potency (~10 fold). Both isomers of hydantoin
analogues (24 and 25) were also less potent than 2. The potency
loss for both tetrazole and hydantoins could be due to the fact
that the increase steric bulk of these groups compared to the
carboxylic acid cannot be accommodated by the small binding
pocket of RORt LBD. The amide 26 had comparable potency
while the ester 27 showed much weaker activity as anticipated.
The carboxylic acid moiety of 2 not only engages multiple
hydrogen bonding interactions with the RORt LBD, but also
improves metabolic stability of the series. Therefore, part of our
SAR optimization efforts was to keep the carboxylic acid group
intact and explore additional substitution to the cyclohexane ring
in order to improve RORt potency. We also envisioned that
rigidification of the cyclohexane ring with fused/bridged bicyclic
scaffolds, while maintaining the two carbonyl groups close to the
1,4-di-equatorial orientation, could lead to potency
improvements. In parallel, we also explored structural diversity
by investigating alternative functional groups to the carboxylic
Compound
28,
one
of
the
two

Table 1. In vitro data of substituted cyclohexane carboxylic acid analogues
cis
F
trans
1
1
2 OH
O
R
2 OH
O
O
O
R
R
R
N
N
CF3
CF3
1
1
4
4
F3C
F3C
F
S
F
F
S
O
O
O
O
A
B
RORt
PXR EC50 nM
(% max.)c
LM (h, m)
Cmpd #
Structure
R1
R2
EC50 nMa,b
(% remaining)d
2
H
Me
Et
F
119 ± 28
79 ± 20
266 ± 119
508 ± 152
56 ± 12
31 ± 24
68 ± 37
594 ± 12
109 ± 53
74 ± 36
183 ± 67
269 ± 40
4177c
>50000 (18)
>50000 (18)
>50000 (6)
>17000 (62)
>50000 (7)
>50000 (6)
97, 86
97, 93
100, -e
100, 70
80, 95
89, 83
-e, -e
A
A
A
A
A
A
A
A
A
A
A
A
B
B
H
3
H
4
H
5
H
6
H
H
H
H
H
H
H
H
F
Me
Et
7
e
8
-
n-Pr
9
>18000 (94)
>50000 (7)
10600 (31)
>50000 (9)
>50000 (19)
>22000 (69)
>50000 (18)
82, 95
100, 88
-e, -e
MeO
MeOCH2
F
10
11
12
13
14
15
100, 99
95, 98
82, 94
85, 100
OH (isomer 1)
OH (isomer 2)
H
H
776c
Me
a Values are means of two or more experiments performed in duplicate unless otherwise noted. b RORt reporter assay was performed using
a Jurkat cell line. c Value from a single experiment performed in duplicate. d Metabolic stability in human and mouse liver microsome;
values are percentage remaining after 10 min of incubation. e Not tested.
Table 2. In vitro data of bicyclic carboxylic acid analogues
O
R
N
CF3
F3C
F
S
F
O
O
RORt
PXR EC50 nM
(% max.)c
LM (h, m)
Cmpd #
R
EC50 nMa,b
(% remaining)d
O
2
119 ± 28
>50000 (18)
>50000 (11)
97, 86
OH
H
O
16
17
18
7295 ± 4358
100, 84
OH
H
H
O
590c
>50000 (15)
>33000 (43)
100, -e
OH
H
H
H
O
1480c
100, 100
OH
O
e
19
20
21
22
392c
-
-e, -e
OH
O
33 ± 11
202 ± 62
293 ± 139
>50000 (6)
>50000 (5)
>50000 (5)
100, 73
90, 94
-e, -e
OH
O
O
OH
O
O
O
OH
a Values are means of two or more experiments performed in duplicate unless otherwise noted. b RORt reporter assay was
performed using a Jurkat cell line. c Value from a single experiment performed in duplicate. d Metabolic stability in human
and mouse liver microsome; values are percentage remaining after 10 min of incubation. e Not tested.

methyl sulfone isomers (cis or trans not assigned), exhibited
similar potency to compound 2. The primary alcohol 30 had
respectful potency of 200 nM in Gal4 assay while the secondary
alcohol 31 was notably less potent. Although several compounds
showed comparable activity to 2 from this effort, no noticeable
potency improvement was observed. Next set of compounds (32-
40) represented analogues where the cyclohexane carboxylic acid
moiety was replaced with cyclic sulfones. The five-membered
cyclic sulfone isomers (32 and 33, absolute stereochemistry not
assigned) had similar activity to 2. It was exciting to find that the
six-membered cyclic sulfone 34 improved RORt potency to 33
nM. To our delight, it also displayed excellent metabolic stability
and PXR selectivity. Thus substitution to the six-membered
cyclic sulfone was pursued. Both methyl and ethyl analogues (35
and 36) lost potency by 2-3 fold compared to 34. On the other
hand, the fluoro analogue 37 maintained RORt potency at 36
nM, good PXR selectivity and metabolic stability. Additional
analogues with more polar hydroxy, hydroxymethyl and methoxy
groups (38-40, respectively) resulted in reduced activity.
Table 3. In vitro data of non-carboxylic acid analogues
O
R
N
CF3
F3C
F
S
F
O
O
RORt
PXR EC50 nM
(% max.)c
LM (h, m)
Cmpd #
R
EC50 nMa,b
(% remaining)d
O
2
119 ± 28
>50000 (18)
>50000 (11)
97, 86
OH
N
N
N
23
24
1260 ± 499
100, 73
N
H
O
NH
1900c
572c
>14000 (28)
84, 81
93, 82
Isomer 1
Isomer 2
N
O
H
O
NH
25
>50000 (3)
>50000 (5)
N
O
H
O
26
27
197 ± 140
1167c
100, 100
-e, -e
NH2
O
e
-
O
O
O
O
Isomer 1
Isomer 2
28
29
30
31
128 ± 56
1800 (29)
88, 69
100, -e
75, 63
86, 58
S
O
336 ± 106
200 ± 107
749 ± 290
>50000 (6)
>50000 (8)
>50000 (13)
S
OH
OH
O
S
O
O
32
33
160 ± 22
129 ± 94
>13000 (49)
7200 (37)
100, 78
100, 96
Isomer 1
Isomer 2
O
S
O
S
34
35
33 ± 11
>50000 (5)
93, 96
-e, -e
O
O
S
102 ± 46
>50000 (10)
O
O
36
83c
5200 (32)
3, 0
S
S
O
F
O
37
38
36 ± 8
>50000 (16)
>50000 (6)
100, 90
100, 90
O
HO
O
123 ± 60
S
O
OH
O
39
40
216 ± 120
146 ± 24
>50000 (8)
>50000 (3)
75, 31
-e, -e
S
S
O
O
O
O
a Values are means of two or more experiments performed in duplicate unless otherwise noted. b RORt reporter assay was
performed using a Jurkat cell line. c Value from a single experiment performed in duplicate. d Metabolic stability in human and
mouse liver microsome; values are percentage remaining after 10 min of incubation. e Not tested.
Compounds 7 and 20 were selected for further evaluation.
Both compounds showed half-life of >120 min in the in vitro
human, rat and mouse liver microsome stability assay. In a Caco-
2 assay, both compounds 7 and 20 exhibited good permeability

(153 and 150 nm/s, respectively) and no detectable efflux (efflux
ratio of 0.7 and 0.9, respectively). Compounds 7 and 20 were
also found to have no significant CYP inhibition liabilities, with
IC50 values greater than 10  against CYP1A2, 2B6, 2C8, 2C9,
2C19, 2D6 and 3A4. Because of their similar in vitro profiles,
both compounds 7 and 20 were taken into mouse PK studies and
the results were compared to compound 2 (Table 4). At an oral
dose of 10 mg/kg, compound 7 displayed Cmax of 3.7 M and
AUC (area under the curve) of 16.6 M*h; and compound 20
achieved Cmax of 6.7  and AUC of 24 M*h which was
comparable to compound 2.
catalyst in dichloromethane yielded a 1:5 mixture of 54 and 55.18
After separation of two isomers, deprotection of each compound
with TFA followed by HATU-mediated coupling with 46 and
saponification provided 16 and 17.
OH
O
O
O
O
O
a
b
OMe
MeO
OMe
MeO
OMe
47
49
48
O
O
d,e
f, g
c
HO
OH
t-BuO
OH
50
51
Table 4. PK profile of 7, 20 and 2 in balb/c micea
O
O
N
CF3
OH
2
Cmpd #
7
20
F3C
F
S
F
O
6.6
3.7
6.7
Cmax (M)
O
7
Scheme 2. Synthesis of 7. Reagents and reaction conditions: (a) TEA, MsCl,
DCM (40%); (b) H2, Crabtree’s catalyst, DCM (98%); (c) DIBAL, toluene, -
78 ºC (99%); (d) H2CrO4, acetone, water (67%); (e) (Boc)2O, DMAP, t-
BuOH (40%); (f) 46, BOP, i-Pr2NEt, DMF (69%); (g) TFA, DCM (83%).
2
Tmax (h)
0.5
1.0
24
36.6
16.6
AUC (M*h)
a Oral dose: 10 mg/kg; vehicle: 5% N-methyl pyrrolidinone
(NMP), 76% PEG 300, 19% TPGS.
O
O
HO
b
a
Schemes 1-4 outline several representative synthesis. Scheme
1 illustrates the synthesis of compound 3. Methylation of diester
41 gave the cis-isomer 42 as the only product. Epimerization of
42 with LDA deprotonation and methanol quenching followed by
saponification provided the diacid 43 as a 1:1 mixture of cis- and
trans-isomers. To facilitate separation of isomers, compound 43
was treated with oxalyl chloride followed by benzyl alcohol to
yield the monobenzyl ester 44. Separation of two isomers of 44
by chiral HPLC followed by hydrogenation gave the desired
trans-diacid 45. BOP-mediated coupling of 45 with intermediate
4614 completed the synthesis of 3.
t-BuO
52
53
H
H
H
H
O
O
O
O
+
t-BuO
OEt
t-BuO
OEt
55
54
c
c
H
H
O
O
O
O
OH
OEt
OH
OEt
H
H
56
d, e
57
O
O
O
O
d, e
O
O
b, c
a
O
O
O
O
HO
OH
MeO
OMe
MeO
OMe
N
41
42
43
N
CF3
OH
CF3
OH
F3C
F3C
F
S
F
F
S
F
g
O
O
O
O
O
O
e, f
O
16
d
O
17
NH
CF3
HO
OH F3C
BnO
OH
F
S
O
F
Scheme 3. Synthesis of 16 and 17. Reagents and reaction conditions: (a)
(Boc)2O, DMAP, t-BuOH (67%); (b) ethyl diazoacetate, Rh2(OAc)4, DCM
(50%); (c) TFA, DCM; (d) 46, HATU, i-Pr2NEt, DMF; (e) LiOH, THF.
O
44
45
46
O
O
N
Scheme 4 describes the synthesis of compounds 21 and 22.
Treatment of ethyl acrylate (58) and two equivalents of diethyl
malonate (59) with sodium hydride in THF provided compound
60. Decarboxylation of 60 followed by protection of the ketone
yielded compound 61. LAH reduction of 61 gave the diol 62.
Conversion of the diol to bis-tosylate followed by ketal
deprotection delivered 63. Grignard addition to the ketone 63
followed by cyclization produced 64. Conversion of the tosylate
to the acetate followed by hydrolysis provided the alcohol 65.
Oxidation of 65 followed by esterification gave 66. Ozonolysis of
66 followed by oxidation yielded the acid 67. HATU-mediated
coupling of 67 with 46 followed by hydrogenation completed the
synthesis of 21. Alternatively, esterification of 67 followed by
hydrogenation gave the acid 68. Coupling of 68 with 46 followed
by hydrolysis completed the synthesis of 22.
CF3
OH
F3C
F
S
F
O
O
3
Scheme 1. Synthesis of 3. Reagents and reaction conditions: (a) LDA, MeI,
THF (78%); (b) LDA, THF, MeOH (83%, 1:1 mixture of cis and trans
isomers); (c) LiOH, THF (94%); (d) (COCl)2, DMF, BnOH, DCM (69%); (e)
chiral OJ-H separation; (f) Pd/C, H2, ethyl acetate (100%); (g) 46, BOP, i-
Pr2NEt, DMF (54%).
Scheme 2 depicts the synthesis of compound 7. In situ self-
dimerization of 47 by treatment of triethylamine and mesyl
chloride
yielded
48.17
Ester-directed
stereoselective
hydrogenation of 48 with Crabtree’s catalyst provided 49 as a
single isomer. Treatment of 49 with DIBAL gave diol 50.
Oxidation of 50 using freshly prepared chromic acid solution
followed by mono esterification produced 51. BOP-mediated
coupling of 51 with 46 followed by deprotection provided 7.
The rest of the compounds exemplified in this manuscript
were prepared by BOP or HATU-mediated coupling of the
common intermediate 46 with the corresponding carboxylic acid
side chain.
Scheme 3 shows the synthesis of compounds 16 and 17.
Treatment of the acid 52 with (Boc)2O and DMAP in tert-butanol
gave the tert-butyl ester 53. Cyclopropanation of 53 with ethyl
diazoacetate was achieved using rhodium (II) acetate dimer as a

7.
(a) Withers, D. R.; Hepworth, M. R.; Wang, X.; Mackley, E. C.;
Halford, E. E.; Dutton, E. E.; Marriott, C. L.; Brucklacher-
Waldert, V.; Veldhoen, M.; Kelsen, J. Nat Med. 2016, 22, 319. (b)
Xue, X.; Soroosh, P.; De Leon-Tabaldo, A.; Luna-Roman, R.;
Sablad, M.; Rozenkrants, N.; Yu, J.; Castro, G.; Banie, H.; Fung-
Leung, W. P. Sci. Rep. 2016, 6, 37977.
Dhar, T. G. M.; Zhao, Q.; Markby, D. W. Annu. Rep. Med. Chem.
2013, 48, 169.
Cyr, P.; Bronner, S. M.; Crawford, J. J. Bioorg. Med. Chem. Lett.
2016, 26, 4387.
In summary, detailed SAR studies around the cyclohexane
carboxylic acid moiety of compound 2 were carried out.
Compounds 7, 20, 34 and 37 all improved RORt inverse agonist
potency by several fold compared to 2. Furthermore, compounds
7 and 20 were found to essentially maintain the desirable
pharmacokinetic profile of 2. Compounds 34 and 37 represent
non-carboxylic acid alternatives with improved potency. The
combination of improved potency, good PK profile and structure
diversity of these new side chains represents significant progress
in the SAR development of the phenyl ((R)-3-phenylpyrrolidin-3-
yl)sulfone series of RORt inverse agonists. Application of these
findings with new core modifications to further improve potency
will be reported in the future.
8.
9.
10. Fauber, B. P.; Magnuson, S. J. Med. Chem. 2014, 57, 5871.
11. Kojetin, D. J.; Burris, T. P. Nat. Rev. Drug Discov. 2014, 13, 197.
12. Pandya, V. B.; Kumar, S.; Sachchidanand, S.; Sharma, R.; Desai,
R. C. J. Med. Chem. 2018, 61, 10976.
13. Gong, H.; Weinstein, D. S.; Lu, Z.; Duan, J. J.-W.; Stachura, S.;
Haque, L.; Karmakar, A.; Hemagiri, H.; Raut, D. K.; Gupta, A.
K.; Khan, J.; Camac, D.; Sack, J. S.; Pudzianowski, A.; Wu, D.-
R.; Yarde, M.; Shen, D.-R.; Borowski, V.; Xie, J. H.; Sun, H.;
D’Arienzo, C.; Dabros, M.; Galella, M. A.; Wang, F.; Weigelt, C.
A.; Zhao, Q.; Foster, W.; Somerville, J. E.; Salter-Cid, L. M.;
Barrish, J. C.; Carter, P. H.; Dhar, T. G. M. Bioorg. Med. Chem.
Lett. 2018, 28, 85.
14. Duan, J. J.-W.; Lu, Z.; Jiang, B.; Stachura, S.; Weigelt, C. A.;
Sack, J. S.; Khan, J.; Ruzanov, M.; Galella, M. A.; Wu, D.-R.;
Yarde, M.; Shen, D.-R.; Shuster, D. J.; Borowski, V.; Xie, J. H.;
Zhang, J.; Vanteru, S.; Gupta, A. K.; Mathur, A.; Zhao, Q.; Foster,
W.; Salter-Cid, L. M.; Carter, P. H.; Dhar, T. G. M. ACS Med.
Chem. Lett. 2019, 10, 367.
15. Attempts to obtain a structure of compound 2 with RORt LBD
using the same protein as reported in references 13 and 14 were
unsuccessful. Therefore, a new RORt LBD construct was used
for the co-crystal structure of compound 2. The new construct
differs from the previous one in that the protein was covalently
OEt
O
O
EtO
EtO
O
O
O
O
O
O
O
O
O
b, c
d
a
+
OEt
EtO
e, f
OEt
EtO
EtO
58
59
60
61
HO
TsO
O
O
g, h
i, j
k, l
O
OTs
OH
O
O
HO
TsO
62
63
64
65
O
HO
O
N
OH
CF3
m, n
O
o, p
OBn
OBn
O
O
F3C
O
F
O
O
F
S
O
66
67
O
21
q, p
O
linked to
a SRC1 peptide which was found to help co-
MeO
O
N
OH
o, r
CF3
crystallization. Details about the modified protein can be found in
the deposited structure (PDB ID 6P9F).
O
F3C
OH
O
F
O
F
S
16. (a) Kiesman, W. F.; Zhao, J.; Conlon, P. R.; Dowling, J. E.; Petter,
R. C.; Lutterodt, F.; Jin, X.; Smits, G.; Fure, M.; Jayaraj, A.; Kim,
J.; Sullivan, G.; Linden, J. J. Med. Chem. 2006, 49, 7119. (b)
Barlind, J. G.; Bauer, U. A.; Birch, A. M.; Birtles, S.; Buckett, L.
K.; Butlin, R. J.; Davies, R. D. M.; Eriksson, J. W.; Hammond, C.
D.; Hovland, R.; Johannesson, P.; Johansson, M. J.; Kemmitt, P.
D.; Lindmark, B. T.; Gutierrez, P. M.; Noeske, T. A.; Nordin, A.;
O’Donnell, C. J.; Petersson, A. U.; Redzic, A.; Turnbull, A. V.;
Vinblad, J. J. Med. Chem. 2012, 55, 10610. (c) Zhong, M.; Peng,
E.; Huang, N.; Huang, Q.; Huq, A.; Lau, M.; Colonno, R.; Li, L. .
Bioorg. Med. Chem. Lett. 2014, 24, 5731.
17. Rensburg, D. J. V.; Mason, P. H.; Emslie, N. D. Synth. Commun.
1996, 26, 4403.
18. Kozhushkov, S. I.; Langer, R.; Yufit, D. S.; Howard, J. A. K.;
Schill, H.; Demus, D.; Miyazawa, K.; Meijere, A. D. Eur. J. Org.
Chem. 2004, 2, 289.
O
O
68
O
22
Scheme 4. Synthesis of 21 and 22. Reagents and reaction conditions: (a)
NaH, THF (51%); (b) NaCl, DMSO, H2O, 160 ºC (88%); (c) ethylene glycol,
TsOH, toluene, reflux (85%); (d) LAH, Et2O, 0 ºC (74%); (e) TsCl, pyridine
(90%); (f) HCl, THF, reflux (94%); (g) vinylmagnesium bromide, THF, -78
ºC; (h) NaH, DME, reflux (55% for two steps); (i) CsOAc, DMF, 100 ºC
(97%); (j) K2CO3, MeOH, H2O (94%); (k) PDC, DMF; (l) BnBr, K2CO3,
DMF (72% for two steps); (m) O3, DCM, Me2S, -78 ºC; (n) NaClO2, 2-
methylbut-2-ene, NaH2PO4, H2O, t-BuOH (85% for two steps); (o) 46,
HATU, i-Pr2NEt, DMF; (p) H2, MeOH; (q) TMSCH2N2, MeOH, toluene; (r)
LiOH, THF.
Acknowledgments
We would like to thank Dr. Robert Borzilleri for critical review
of the manuscript.
References and notes
1.
2.
Jetten, A. M. Nucl. Recept. Signal. 2009, 7, e003.
Cook, D. N.; Kang, H. S.; Jetten, A. M. Nucl. Receptor Res. 2015,
2, Article ID 101185.
3.
Ivanov, I. I.; McKenzie, B. S.; Zhou, L.; Tadokoro, C. E.;
Lepelley, A.; Lafaille, J. J.; Cua, D. J.; Littman, D. R. Cell 2006,
126, 1121.
4.
5.
6.
Elloso, M. M.; Gomez-Angelats, M.; Fourie, A. M. J. Leukoc.
Biol. 2012, 92, 1187.
Rizvi, S.; Chaudhari, K.; Syed, B. A. Nat. Rev. Drug Discov.
2015, 14, 745.
(a) Chabaud, M.; Durand, J. M.; Buchs, N.; Fossiez, F.; Page, G.;
Frappart, L.; Miossec, P. Arthritis Rheum. 1999, 42, 963. (b)
Lock, C.; Hermans, G.; Pedotti, R.; Brendolan, A.; Schadt, E.;
Garren, H.; Langer-Gould, A.; Strober, S.; Cannella, B.; Allard, J.;
Klonowski, P.; Austin, A.; Lad, N.; Kaminski, N.; Galli, S. J.;
Oksenberg, J. R.; Raine, C. S.; Heller, R.; Steinman, L. Nat. Med.
2002, 8, 500. (c) Seiderer, J.; Elben, I.; Diegelmann, J.; Glas, J.;
Stallhofer, J.; Tillack, C.; Pfennig, S.; Jürgens, M.; Schmechel, S.;
Konrad, A.; Göke, B.; Ochsenkühn, T.; Müller-Myhsok, B.;
Lohse, P.; Brand, S. Inflamm. Bowel Dis. 2008, 14, 437.

SAR optimization
O
O
O
O
O
O
N
N
CF3
N
CF3
CF3
CF3
OH
OH
OH
F3C
F3C
F3C
F3C
F
F
S
F
F
S
F
F
S
F
O
O
O
O
O
O
2
7
20
RORt EC50 = 33 nM
Orally bioavailable in mouse
RORt EC50 = 119 nM
RORt EC50 = 31 nM
Orally bioavailable in mouse
ROR
19.