Synthesis and biological activities of 4-phenyl-5-pyridyl-1,3-thiazole derivatives as p38 MAP kinase inhibitors

Article abstract of DOI:10.1248/cpb.53.410

A novel series of 4-phenyl-5-pyridyl-1,3-thiazole analogues possessing potent in vitro inhibitory activity against p38 mitogen-activated protein kinase and the release of tumor necrosis factor-α (TNF-α) from human monocytic THP-1 cells stimulated by lipopolysaccharide has been identified. Subsequent structure-activity relationship (SAR) studies and optimization for absorption, distribution, metabolism, and elimination (ADME) profiles led to the identification of compounds 7g and 10b as orally active lead candidates that block the in vivo production of proinflammatory cytokine (TNF-α). In pharmacokinetic studies, compound 10b showed good oral administration in mice and demonstrated significant in vivo anti-inflammatory activity in an anti-collagen monoclonal antibody-induced arthritis mouse model (minimum effective dose (MED)=30 mg/kg). Further elucidation of this class of compounds may provide novel anti-inflammatory agents, such as anti-rheumatoid arthritis drugs.

Full text of DOI:10.1248/cpb.53.410

410
Chem. Pharm. Bull. 53(4) 410—418 (2005)
Vol. 53, No. 4
Synthesis and Biological Activities of 4-Phenyl-5-pyridyl-1,3-thiazole
Derivatives as p38 MAP Kinase Inhibitors
Seiji MIWATASHI,* Yasuyoshi ARIKAWA, Ken-ichi NARUO, Keiko IGAKI, Yasumasa WATANABE,
Hiroyuki KIMURA, Tomohiro KAWAMOTO, and Shigenori OHKAWA
Pharmaceutical Research Division, Takeda Pharmaceutical Company, Ltd.; 2–17–85 Jusohonmachi, Yodogawa-ku, Osaka,
532–8686, Japan. Received December 16, 2004; accepted February 2, 2005
A novel series of 4-phenyl-5-pyridyl-1,3-thiazole analogues possessing potent in vitro inhibitory activity
against p38 mitogen-activated protein kinase and the release of tumor necrosis factor-a (TNF-a) from human
monocytic THP-1 cells stimulated by lipopolysaccharide has been identified. Subsequent structure–activity rela-
tionship (SAR) studies and optimization for absorption, distribution, metabolism, and elimination (ADME) pro-
files led to the identification of compounds 7g and 10b as orally active lead candidates that block the in vivo pro-
duction of proinflammatory cytokine (TNF-a). In pharmacokinetic studies, compound 10b showed good oral ad-
ministration in mice and demonstrated significant in vivo anti-inflammatory activity in an anti-collagen mono-
clonal antibody-induced arthritis mouse model (minimum effective dose (MED)ꢀ30 mg/kg). Further elucidation
of this class of compounds may provide novel anti-inflammatory agents, such as anti-rheumatoid arthritis drugs.
Key words 5-pyridyl-1,3-thiazole; p38 mitogen-activated protein (MAP) kinase; rheumatism; tumor necrosis factor (TNF)-a;
anti-collagen monoclonal antibody-induced arthritis
Tumor necrosis factor-a (TNF-a) is a pro-inflammatory date the mechanism, we found that 2-amino-4-phenyl-5-
cytokine, mainly produced by activated monocytes and pyridyl-1,3-thiazole derivatives had potent adenosine recep-
macrophages. Excessive production of TNF-a is believed to tor antagonistic activity and phosphodiesterase inhibitory ac-
underlie the progression of many serious inflammatory dis- tivity.10) These receptors and enzymes are related to adeno-
eases, such as rheumatoid arthritis (RA), Crohn’s disease and sine or adenosine-3,5-triphosphate (ATP), suggesting that 4-
psoriasis.1,2) Recent clinical data, obtained using chimeric phenyl-5-pyridyl-1,3-thiazole derivatives mimic adenosine
TNF-a antibodies3,4) and soluble TNF-a receptor fusion pro- and its related substrates. Taking these results into considera-
teins5) in the treatment of RA, have confirmed the important tion, we explored the 4-phenyl-5-pyridyl-1,3-thiazole tem-
role of TNF-a in these inflammatory conditions. These plate, including rarely reported 2-acetylaminothiazole com-
agents are generally well tolerated but have drawbacks relat- pounds. Herein, we report the synthesis and biological activi-
ing to patient cost, efficiency of production, and administra- ties of a novel series of 4-phenyl-5-pyridyl-1,3-thiazole de-
tion by injection. Therefore, inflammation research has fo- rivatives as p38 MAP kinase inhibitors.
cused on the development of orally active small molecular
inhibitors of cytokine release.
Chemistry
A serine/threonine kinase termed p38 mitogen-activated
The general approach for the synthesis of 4,5-disubstituted
protein (MAP) kinase is a member of the stress-activated 2-acetylamino-1,3-thiazoles 7 is outlined in Chart 1. The 1-
protein kinases and is considered as an attractive target. The benzoyl-2-methylaziridines 2 were prepared from the corre-
prototypical p38 MAP kinase inhibitor SB 203580 (Fig. 1) sponding acid chloride and commercially available 2-methyl-
showed inhibitory activity in vivo against pro-inflammatory aziridine according to the Schotten–Baumann procedure. The
cytokine production in both mice and rats,6) and several novel lithium anion of methylpyridine 3 was condensed with 1-
structural classes of p38 MAP kinase inhibitors have been benzoyl-2-methylaziridines 2 and the resulting ketones 4
demonstrated to efficiently reduce cytokine levels.7) Thus, the
regulation of TNF-a via the inhibition of p38 MAP kinase is
expected to have beneficial effects in the treatment of inflam-
matory diseases. Although the efforts to develop small mole-
cule agents for p38 MAP kinase have not yet yielded an
agent ready to market, several inhibitors are presently under
investigation in human clinical trials.
We have previously reported that 4-phenyl-5-pyridyl-1,3-
thiazole derivatives showed strong anti-inflammatory activi-
ties8,9) but the anti-inflammatory mechanism of these com-
pounds was not well-known. In a continuing effort to eluci-
Fig. 1. Structure of SB 203580
Chart 1. Synthesis of 2-Acetylaminothiazoles (7)
© 2005 Pharmaceutical Society of Japan
∗ To whom correspondence should be addressed. e-mail: Miwatashi_Seiji@takeda.co.jp

April 2005
411
were brominated to give a-bromoketones 5.11) Condensation
of 5 with thiourea afforded 1,3-thiazoles 6. Since the subse-
quent acetylation of 6 under various standard conditions
(acetic anhydride or acetyl chloride with triethylamine, or the
Schotten–Baumann procedure) was unsuccessful due to the
low reactivity of the amino moiety, we used N,N-dimethyl-4-
aminopyridine (DMAP) as a catalyst in the reaction with
acetyl chloride in N,N-dimethylacetamide (DMA).
The 4,5-disubstituted 2-alkyl(aryl)-1,3-thiazoles 8 were
prepared from a-bromoketones 5 and thioamides 13 (Chart
2), which were prepared from the corresponding nitriles ac-
cording to a process described in the previous report.12) The
cyclization reaction under previous condition using triethyl-
amine as a base gave 8 in low to moderate yields, but an im-
provement in yield was achieved when no base was used.
However, even under these conditions, the cyclization reac-
tion of 5 and thioacetoamide 8c proceeded with low yield
Chart 2. Synthesis of 2-Alkyl(aryl)-thiazoles (8—12)
(20%) and ketone 4 was the major product obtained. Sulfide (8e—i) enhanced the potency. The compound 8g with a
8i was converted into the corresponding sulfoxide 9 on treat- methyl group at the 4-position was more active than 2-
ment with potassium peroxodisulfate in aqueous acetic methylphenyl (8e) or 3-methylphenyl (8f).
acid.13) The sulfonyl derivatives 10a and 10b were synthe-
To evaluate the role of the substituent on the 2-phenyl ring,
sized by oxidization of the corresponding sulfide 8i or 8k we examined a docking study between 10b and p38 MAP ki-
using 2 equivalents of m-chloroperbenzoic acid (mCPBA) in nase using the DOCK program based on the X-ray crystal
N,N-dimethylformamide (DMF). Saponification of 8j pro- structure of the complex between SB 203580 and p38 MAP
vided the corresponding carboxylic acid 11. Thiazole 8a was kinase.15) The result of this study, as shown in Fig. 2, sug-
oxidized with mCPBA in DMF to afford N-oxide 12. All the gested that the 4-methylsulfonylphenyl ring of 10b could
synthesized thiazoles are listed in Table 1.
form p–p staking interaction with Tyr 35 of the enzyme and
an appropriate substituent on the phenyl ring would have the
potency to derive additional contact with Arg 173 of the en-
Results and Discussion
The p38 MAP kinase inhibitory activities of 1,3-thiazole zyme. The potency of sulfoxide 9 and sulfone 10a compared
derivatives are shown in Table 2. Firstly, the structure–activ- to sulfide 8i strongly supported the validity of this further
ity relationship (SAR) around the pyridine ring at the 5-posi- contribution to binding potency. The phenol analogue 8h re-
tion of the thiazole nucleus was evaluated with 7a—c and 12. tained potent activity, while carboxylic acid analogue 11 re-
The 2- and 3-pyridyl derivatives 7c and 7b led to a drastic sulted in decreased activity.
loss in activity, indicating that the 4-pyridyl group is essential
These compounds were further evaluated for their in-
for inhibitory activity. The diminished potency of N-oxide 12 hibitory activity by the lipopolysaccharide (LPS)-stimulated
indicated the importance of the nitrogen atom of the 4- TNF-a release assay using the THP-1 cell for secondary
pyridyl moiety as a hydrogen bond acceptor. According to screening (Table 2). There was no outstanding difference in
the previous X-ray crystallographic data, the nitrogen atom p38 MAP kinase inhibitory activity between compounds
seems to form a crucial hydrogen bond with the backbone bearing methoxy (7a, d) or chloro (7i, j) substituents. How-
NH of Met 109 in the enzyme.14—16)
ever, in this cell-based assay, compounds 7a and 7i with sub-
Next, we focused on the SAR around the phenyl ring at 4- stituents at 4-position on the phenyl ring showed 5-fold and
position. The bulky substituents, for example 4-tert-butyl 22-fold more potency than 7d and 7j with substituents at 3-
(7m), had weak activity but the small substituents, such as 4- position, respectively. On the other hand, the 3-methyl ana-
methyl (7f) or 4-chloro (7i) were tolerated. The introduction logue 7g exhibited improved activity compared to the 4-
of substituents at the 2-position of the phenyl ring led to con- methyl derivative 7f, suggesting that methyl analogues pro-
siderably less active compounds (7e, h, k). In addition, 3- duce a significantly different SAR.
chloro (7j) showed superior activity to 3-methoxy (7d) or 3-
To investigate the structural requirement of 4-(3-
fluoro (7l). These results suggested that the steric require- methylphenyl)thiazole derivatives in more detail, compounds
ment is a more important factor than the electronic factor. with various substituents at 2 position of the thiazole ring
The most interesting compound in these 2-acetylaminothia- were further profiled for their ability to inhibit TNF-a pro-
zoles was the 3-methyl derivative 7g. Based on these results, duction. The amino (6g), which had strong inhibitory activity
we selected the 3-methyl group as a favorable substituent on against p38 MAP kinase, showed less activity than 2-acetyl-
the phenyl ring for the next SAR study around the 2-position amino (7g). Lower-alkyl substituents, such as methyl (8c) or
of the thiazole.
ethyl (8a), were well tolerated, but tert-butyl (8b) and phenyl
The 2-amino derivative 6g can also provide good in- (8d) gave less activity. Little difference was observed in the
hibitory affinity as seen with the acetyl amino compound 7g. series of 2-phenyl (8e—g). Although phenol (8h) was the
The lower alkyl substituents (8a—c) were tolerated and the most potent p38 MAP kinase inhibitor in this series, sulfox-
ethyl derivative 8a was the most potent in this series. The 2- ide (9) and sulfone (10a) were much better tolerated than 8h
phenyl analogue 8d did not result in improved activity. How- in the cellular assay. It seemed that the hydrophobic sub-
ever, the introduction of substituents on the phenyl ring stituents at 2-positon, such as methyl or ethyl, or less polar

412
Vol. 53, No. 4
Table 1. Physicochemical Properties of 5-Pyridyl-1,3-thiazoles
Compd.
Py
4-Py
R1
R4
Formula
C15H13N3OS
C15H13N3OS
C15H13N3OS
C15H13N3OS
C15H13N3OS·0.2H2O
C15H13N3S
Yield (%)a)
mp (°C)
Anal.
6a
6b
6c
6d
6e
6f
6g
6h
6i
4-MeO
4-MeO
4-MeO
3-MeO
2-MeO
4-Me
3-Me
2-Me
4-Cl
NH2
NH2
NH2
NH2
NH2
NH2
NH2
NH2
NH2
NH2
NH2
NH2
NH2
68
90
55
37
61
75
72
42
73
60
24
86
69
67
92
82
29
70
54
54
68
56
73
57
47
82
50
64
59
53
20
74
68
76
72
78
45
58
84
58
63
71
74
74
282—284
265—266
217—218
232—234
213—215
296—298
255—258
235—238
ꢀ300
256—258
232—235
263—264
254—257
199—202
282—284
119—120
230—232
234—236
259—261
308—309
287—289
272—274
317—320
290—293
292—293
326—328
280—281
169—170
56—58
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
3-Py
2-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
3-Py
2-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py oxide
C15H13N3S
C15H13N3S·0.2H2O
C14H10ClN3S
C14H10ClN3S
C14H10ClN3S
C14H10FN3S
6j
6k
6l
3-Cl
2-Cl
3-F
6m
6n
7a
7b
7c
7d
7e
7f
7g
7h
7i
7j
7k
7l
7m
7n
8a
8b
8c
8d
8e
8f
8g
8h
8i
8j
8k
9
4-tBu
3-Me
4-MeO
4-MeO
4-MeO
3-MeO
2-MeO
4-Me
3-Me
2-Me
4-Cl
C18H19N3S·0.5H2O
C16H15N3S
NHMe
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NMeAc
Et
C17H15N3O2S
C17H15N3O2S
C17H15N3O2S
C17H15N3O2S·0.3H2O
C17H15N3O2S
C17H15N3OS
C17H15N3OS
C17H15N3OS
C16H12ClN3OS·0.2H2O
C16H12ClN3OS
C16H12ClN3OS
C16H12FN3OS
C20H21N3OS
C18H17N3OS
C17H16N2S
C19H20N2S
C16H14N2S
C21H16N2S
C22H18N2S
C22H18N2S
C22H18N2S
C21H16N2OS
C22H18N2S2
3-Cl
2-Cl
3-F
4-tBu
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
4-F
tBu
Me
Ph
140—142
74—75
118—120
Paste
2-MeC6H4
3-MeC6H4
4-MeC6H4
4-HOC6H4
4-MeSC6H4
4-MeOCOC6H4
4-MeSC6H4
4-MeSOC6H4
4-MeSO2C6H4
4-MeSO2C6H4
4-HOCOC6H4
Et
86—87
138—139
248—249
101—102
152—153
115—118
188—189
171—174
191—194
335—336
143—144
C23H18N2O2S
C21H15FN2S2
C22H18N2OS2
C22H18N2O2S2
C21H15FN2O2S2
C22H16N2O2S
C17H16N2OS
3-Me
3-Me
4-F
3-Me
3-Me
10a
10b
11
12
a) No attempt was made to optimize yields. Numbers respect the yield for the last step.
substituents, such as sulfinyl or sulfonyl, were superior to compound 10b in particular had a more favorable pharmaco-
polar substituents, such as amino and phenol, in the cellular kinetic (PK) profile in mice. Although the Novartis group has
assay.
reported that pyridylthiazole has no activity in in vivo LPS
Based on p38 MAP kinase inhibition, TNF-a release mice,17) these compounds showed significant anti-TNF-a ac-
assay results and the structural features, the three com- tivity in vivo and good oral absorption. In our effort to obtain
pounds, 2-acetamide (7g), 2-sulfonylphenyl derivatives 10a an orally active p38 MAP kinase inhibitor, compounds 7g
and 10b, were selected for the in vivo assay (Table 3). Com- and 10b provided evidence of the potency of thiazole nu-
pound 7g inhibited TNF-a production by 43% while 10b cleus.
was still more effective with 67% inhibition. Compound 10a
To evaluate the in vivo potency of p38 MAP kinase in-
showed no activity in this model at 10 mg/kg. These data hibitor as an anti-RA drug, compound 10b (10—50 mg/kg;
suggest that the fluoro group has greater in vivo efficacy than p.o.) was tested in an anti-collagen (anti-CII) monoclonal an-
the methyl group. We therefore examined the mouse plasma tibody (mAb)-induced arthritis mouse model, as shown in
concentration after oral administration of 7g and 10b (Table Fig. 3. In this mouse model, severe arthritis occurs about 24 h
3). These two compounds demonstrated good results and after LPS injection and persists for more than 21 d.18) Treat-

April 2005
413
Table 2. Inhibitory Activities of Pyridylthiazoles on p38 MAP Kinase and LPS-Stimulated Release of TNF-a in THP-1 Cells
IC50 (nM)
Compd.
Py
R1
R4
p38aa)
TNF-aa)
(140—880)
6g
7a
7b
7c
7d
7e
7f
7g
7h
7i
4-Py
3-Me
NH2
7.3
74
ꢀ1000
ꢀ1000
73
1300
76
8.9
340
45
(5.7—9.4)
(57—95)
350
240
NTb)
NTb)
1200
NTb)
220
80
210
170
3700
850
4600
NTb)
3100
73
4-Py
3-Py
2-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py
4-Py oxide
4-MeO
4-MeO
4-MeO
3-MeO
2-MeO
4-Me
3-Me
2-Me
4-Cl
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
NHAc
(100—590)
(48—110)
(910—1800)
(67—86)
(6.9—11)
(210—330)
(37—54)
(36—51)
(210—330)
(110—190)
(250—5800)
(48—980)
(32—200)
(64—690)
(67—420)
7j
7k
7l
3-Cl
2-Cl
3-F
43
(580—24000)
(390—1900)
(570—38000)
260
140
ꢀ1000
48
7m
7n
8a
8b
8c
8d
8e
8f
4-tBu
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
3-Me
4-F
NMeAc
(34—67)
(12—19)
(25—40)
(23—32)
(160—250)
(55—87)
(65—84)
(33—53)
(3.9—7.2)
(19—26)
(11—19)
(12—16)
(nꢁ1)
(800—12000)
(36—150)
(270—2500)
(34—130)
(960—2700)
(180—640)
(150—1000)
(190—1300)
(81—220)
(1200—12000)
(32—140)
(29—84)
(190—760)
(54—550)
Et
15
31
27
200
69
74
41
5.3
22
15
tBu
820
66
Me
Ph
1600
340
380
510
130
3800
67
2-MeC6H4
3-MeC6H4
4-MeC6H4
4-HOC6H4
4-MeSC6H4
4-MeSOC6H4
4-MeSO2C6H4
4-MeSO2C6H4
4-HOCOC6H4
Et
8g
8h
8i
9
10a
10b
11
12
14
51
210
1700
49
380
170
NTb)
3-Me
3-Me
(170—280)
(1100—2800)
a) Numbers in parentheses represent 95% confidence intervals or remark; b) NT indicates ‘not tested’.
Fig. 2. Docking Model of Compound 10b with p38 MAP Kinase
Table 3. Inhibitory Activities of Pyridylthiazoles on LPS-Induced TNF-a ment with compound 10b (30, 50 mg/kg; p.o.) demonstrated
Production in Mice and Pharmacokinetic Parameters
a significant ameliorative effect on the arthritis by preventing
the development of footpad swelling (on day 11).
LPS mouse
Mouse PKb)
(10 mg/kg, p.o.)
(10 mg/kg, p.o.)
Compd.
Conclusion
% inh.a)
Cmax (mg/ml) AUC0—24 h (mg·h/ml)
A series of novel thiazole analogues possessing potent in
vitro inhibitory activity against p38 MAP kinase has been
identified. The introduction of various substituents onto the
phenyl ring and 2-position of the thiazole ring produced in-
hibitors with increased in vitro potency while maintaining
excellent potency in the cellular assay. The potent analogue
10b inhibited p38 MAP kinase with an IC50 of 51 nM and
7g
10a
10b
43.3*
7.3
67.4*
1.078
NTc)
2.420
0.874
NTc)
19.778
a) ∗ pꢂ0.01 vs. LPS-treated control (nꢁ7); b) nꢁ3; c) NT indicates ‘not tested’.

414
Vol. 53, No. 4
pared from 2-methylbenzoyl chloride as described in the synthesis of 2a, as
1
an oil, yield quant.: H-NMR (CDCl3) d: 1.30 (3H, d, Jꢁ5.5 Hz), 2.08 (1H,
d, Jꢁ3.3 Hz), 2.43—2.57 (5H, m), 7.20—7.31 (2H, m), 7.33—7.43 (1H, m),
7.89 (1H, d, Jꢁ7.7 Hz).
1-(4-Chlorobenzoyl)-2-methylaziridine (2g) This compound was pre-
pared from 4-chlorobenzoyl chloride as described in the synthesis of 2a, as
1
an oil, yield quant.: H-NMR (CDCl3) d: 1.39 (3H, d, Jꢁ5.5 Hz), 2.15 (1H,
d, Jꢁ2.9 Hz), 2.51—2.66 (2H, m), 7.39—7.47 (2H, m), 7.93—8.01 (2H, m).
1-(3-Chlorobenzoyl)-2-methylaziridine (2h) This compound was pre-
pared from 3-chlorobenzoyl chloride as described in the synthesis of 2a, as
1
an oil, yield quant.: H-NMR (CDCl3) d: 1.40 (3H, d, Jꢁ5.1 Hz), 2.17 (1H,
d, Jꢁ3.3 Hz), 2.53—2.68 (2H, m), 7.40 (1H, dd, Jꢁ8.1, 7.7 Hz), 7.53 (1H,
ddd, Jꢁ8.1, 2.2, 1.5 Hz), 7.90 (1H, dt, Jꢁ7.7, 1.5 Hz), 8.00 (1H, dd, Jꢁ2.2,
1.5 Hz).
1-(2-Chlorobenzoyl)-2-methylaziridine (2i) This compound was pre-
pared from 2-chlorobenzoyl chloride as described in the synthesis of 2a, as
an oil, yield quant.: H-NMR (CDCl3) d: 1.30 (3H, d, Jꢁ5.1 Hz), 2.12 (1H,
d, Jꢁ3.3 Hz), 2.53 (1H, d, Jꢁ5.5 Hz), 2.56—2.68 (1H, m), 7.28—7.48 (3H,
m), 7.75—7.81 (1H, m).
Fig. 3. Effect of Compound 10b on the Size of Hind Paws in Anti-colla-
gen Antibody-Induced Arthritis of Female BALB/c Mice
1
∗ pꢂ0.05 vs. Intact; # pꢂ0.05 vs. vehicle; Dunnett type test (nꢁ6).
1-(4-Fluorobenzoyl)-2-methylaziridine (2j) This compound was pre-
pared from 4-fluorobenzoyl chloride as described in the synthesis of 2a, as
an oil, yield quant.: 1H-NMR (CDCl3) d: 1.39 (3H, d, Jꢁ5.2 Hz), 2.14—
2.15 (1H, m), 2.52—2.63 (2H, m), 7.08—7.19 (2H, m), 8.00—8.10 (2H, m).
1-(3-Fluorobenzoyl)-2-methylaziridine (2k) This compound was pre-
pared from 3-fluorobenzoyl chloride as described in the synthesis of 2a, as
an oil, yield 77%: 1H-NMR (CDCl3) d: 1.40 (3H, d, Jꢁ5.5 Hz), 2.16 (1H, d,
Jꢁ3.3 Hz), 2.52—2.68 (2H, m), 7.25 (1H, ddd, Jꢁ8.4, 2.6, 1.1 Hz), 7.43
(1H, ddd, Jꢁ8.1, 7.7, 5.5 Hz), 7.69 (1H, ddd, Jꢁ8.1, 2.6, 1.5 Hz), 7.81 (1H,
ddd, Jꢁ7.7, 1.5, 1.1 Hz).
TNF-a production by 67% in mice at 10 mg/kg. This com-
pound also displayed a significant ameliorative effect on the
mouse anti-CII mAb-induced arthritis model (MED:
30 mg/kg; p.o.). The excellent in vitro and in vivo potency of
this series warrants further investigation in more advanced
analogues for the treatment of inflammatory diseases.
Experimental
General Melting points were determined on Yanagimoto micro melting
point apparatus or Büche B-545 and are uncorrected. 1H-NMR spectra were
recorded on a Varian Gemini-200 (200 MHz) spectrometer, with tetra-
methylsilane as the internal standard. TLC analyses were carried out on
Merck Kieselgel 60 F254 plates. Elemental analyses were carried out by
Takeda Analytical Laboratories, Ltd., and are within ꢃ0.4% of the theoreti-
cal values unless otherwise noted. Tetrahydrofuran (THF) was distilled over
calcium hydride before use and other solvents and reagents were used with-
out purification. Extracted solutions were dried over anhydrous Na2SO4 un-
less otherwise noted and concentration of the organic solution was carried
out under reduced pressure. Chromatographic purification was carried out
on silica gel columns (Kieselgel 60, 0.063—0.22 mm, Merck) unless other-
wise noted. The yields reported are not optimized.
1-(4-Methoxybenzoyl)-2-methylaziridine (2a) A solution of 2-methyl-
aziridine (50.5 ml, 0.645 mol) in diethyl ether (325 ml) was added to a 2 N
aqueous sodium hydroxide (325 ml). This mixture was cooled to 0 °C and 4-
methoxybenzoyl chloride (100 g, 0.586 mol) was added dropwise to the mix-
ture. After the addition, the mixture was further stirred for 1 h at 0 °C. The
organic phase was separated and the aqueous phase was extracted with ethyl
ether. The combined organic phase was dried, and concentrated to afford
112 g (yield quant.) of 2a as an oil: 1H-NMR (CDCl3) d: 1.39 (3H, d,
Jꢁ5.9 Hz), 2.11 (1H, d, Jꢁ3.3 Hz), 2.50—2.63 (2H, m), 3.87 (3H, s), 6.94
(2H, d, Jꢁ9.2 Hz), 8.00 (2H, d, Jꢁ9.2 Hz).
1-(3-Methoxybenzoyl)-2-methylaziridine (2b) This compound was
prepared from 3-methoxybenzoyl chloride as described in the synthesis of
2a, as an oil, yield quant.: 1H-NMR (CDCl3) d: 1.40 (3H, d, Jꢁ5.9 Hz), 2.14
(1H, d, Jꢁ2.9 Hz), 2.52—2.65 (2H, m), 3.86 (3H, s), 7.10 (1H, ddd, Jꢁ8.4,
2.6, 1.1 Hz), 7.37 (1H, dd, Jꢁ8.4, 7.3 Hz), 7.55 (1H, dd, Jꢁ2.6, 1.5 Hz),
7.63 (1H, ddd, Jꢁ7.3, 1.5, 1.1 Hz).
1-(2-Methoxybenzoyl)-2-methylaziridine (2c) This compound was
prepared from 2-methoxybenzoyl chloride as described in the synthesis of
2a, as an oil, yield quant.: 1H-NMR (CDCl3) d: 1.30 (3H, d, Jꢁ5.5 Hz), 2.10
(1H, d, Jꢁ3.3 Hz), 2.50 (1H, d, Jꢁ5.9 Hz), 2.53—2.65 (1H, m), 3.90 (3H,
s), 6.95—7.05 (2H, m), 7.41—7.52 (1H, m), 7.81—7.88 (1H, m).
1-(4-Methylbenzoyl)-2-methylaziridine (2d) This compound was pre-
pared from 4-methylbenzoyl chloride as described in the synthesis of 2a, as
an oil, yield 91%: 1H-NMR (CDCl3) d: 1.39 (3H, d, Jꢁ5.5 Hz), 2.12 (1H, d,
Jꢁ2.9 Hz), 2.42 (3H, s), 2.50—2.62 (2H, m), 7.25 (2H, d, Jꢁ8.1 Hz), 7.92
(2H, d, Jꢁ8.1 Hz).
1-[4-(1,1-Dimethylethyl)benzoyl]-2-methylaziridine (2l) This com-
pound was prepared from 4-tert-butylbenzoyl chloride as described in the
1
synthesis of 2a, as an oil, yield quant.: H-NMR (CDCl3) d: 1.35 (9H, s),
1.41 (3H, d, Jꢁ5.5 Hz), 2.12 (1H, d, Jꢁ2.9 Hz), 2.51—2.64 (2H, m), 7.47
(2H, d, Jꢁ8.8 Hz), 7.96 (2H, d, Jꢁ8.8 Hz).
1-(4-Methoxyphenyl)-2-(4-pyridyl)ethanone (4a) Under argon atmo-
sphere, a solution of diisopropylamine (46.3 ml) in THF (300 ml) was cooled
to ꢄ78 °C and a solution of 1.6 M n-butyllithium in hexane (208 ml) was
added dropwise to the solution. After addition, the solution was stirred for
10 min and a solution of 4-methylpyridine (3) (28.3 ml) in THF (30 ml) was
added dropwise to the LDA solution. The reaction mixture was allowed to
warm up to ꢄ10 °C and stirred for 20 min. The resulting mixture was cooled
to ꢄ78 °C and a solution of 2a (57.4 g) in THF (30 ml) was added dropwise
to the mixture. After addition, the mixture was stirred for 1 h at ꢄ78 °C, and
then the reaction mixture was allowed to warm to room temperature. Water
(300 ml) was added to the mixture and the organic phase was separated. The
aqueous phase was extracted with ethyl acetate and the combined organic
phases were dried and concentrated to give a crude crystal. This was recrys-
tallized from ethyl acetate to afford 36.5 g (yield 54%) of 4a as a solid, mp
1
103—104 °C, H-NMR (CDCl3) d: 3.88 (3H, s), 4.24 (2H, s), 6.96 (2H, d,
Jꢁ9.0 Hz), 7.21 (2H, d, Jꢁ6.0 Hz), 7.98 (2H, d, Jꢁ9.0 Hz), 8.56 (2H, d,
Jꢁ6.2 Hz).
1-(4-Methoxyphenyl)-2-(3-pyridyl)ethanone (4b) This compound was
prepared from 2a and 3-methylpyridine as described in the synthesis of 4a
as a solid, yield 85%, mp 71—72 °C (ethyl acetate–hexane), 1H-NMR
(CDCl3) d: 3.88 (3H, s), 4.25 (2H, s), 6.96 (2H, d, Jꢁ8.8 Hz), 7.29 (1H, d,
Jꢁ4.8 Hz), 7.59—7.63 (1H, m), 8.01 (2H, d, Jꢁ8.8 Hz), 8.50—8.52 (2H,
m).
1-(4-Methoxyphenyl)-2-(2-pyridyl)ethanone (4c) This compound was
prepared from 2a and 2-methylpyridine as described in the synthesis of 4a
as a solid, yield 66%, mp 103—104 °C (ethyl acetate–hexane), 1H-NMR
(CDCl3) d: 3.86 (3H, s), 4.45 (2H, s), 6.93 (2H, d, Jꢁ8.8 Hz), 7.17 (1H, dd,
Jꢁ7.3, 4.8 Hz), 7.31 (1H, d, Jꢁ8.1 Hz), 7.64 (1H, ddd, Jꢁ8.1, 7.3, 1.3 Hz),
8.06 (2H, d, Jꢁ8.8 Hz), 8.56 (1H, dd, Jꢁ4.8, 1.8 Hz).
1-(3-Methoxyphenyl)-2-(4-pyridyl)ethanone (4d) This compound was
prepared from 2b as described in the synthesis of 4a as an oil, yield 44%,
1H-NMR (CDCl3) d: 3.86 (3H, s), 4.28 (2H, s), 7.14 (1H, ddd, Jꢁ8.1, 2.6,
1.1 Hz), 7.20 (2H, d, Jꢁ6.2 Hz), 7.36 (1H, dd, Jꢁ8.1, 7.7 Hz), 7.51 (1H, dd,
Jꢁ2.6, 1.5 Hz), 7.58 (1H, ddd, Jꢁ7.7, 1.5, 1.1 Hz), 8.57 (2H, d, Jꢁ6.2 Hz).
1-(2-Methoxyphenyl)-2-(4-pyridyl)ethanone (4e) This compound was
prepared from 2c as described in the synthesis of 4a as an oil, yield 59%,
1H-NMR (CDCl3) d: 3.92 (3H, s), 4.30 (2H, s), 6.95—7.07 (2H, m), 7.17
(2H, d, Jꢁ5.9 Hz), 7.50 (1H, ddd, Jꢁ8.4, 7.3, 1.8 Hz), 7.73 (1H, dd, Jꢁ7.7,
1.8 Hz), 8.53 (2H, d, Jꢁ5.9 Hz).
1-(3-Methylbenzoyl)-2-methylaziridine (2e) This compound was pre-
pared from 3-methylbenzoyl chloride as described in the synthesis of 2a, as
1
an oil, yield quant.: H-NMR (CDCl3) d: 1.39 (3H, d, Jꢁ5.5 Hz), 2.14 (1H,
d, Jꢁ3.3 Hz), 2.41 (3H, s), 2.51—2.66 (2H, m), 7.32—7.39 (2H, m), 7.79—
7.87 (2H, m).
1-(2-Methylbenzoyl)-2-methylaziridine (2f) This compound was pre-
1-(4-Methylphenyl)-2-(4-pyridyl)ethanone (4f) This compound was

April 2005
415
prepared from 2d as described in the synthesis of 4a as a solid, yield 70%,
(5f) This compound was prepared from 4f as described in the synthesis of
1
1
mp 110—111 °C (ethyl acetate–isopropyl ether), H-NMR (CDCl3) d: 2.43 5a as a solid, yield quant., H-NMR (DMSO-d6) d: 2.41 (3H, s), 4.52 (1H,
(3H, s), 4.26 (2H, s), 7.20 (2H, d, Jꢁ5.9 Hz), 7.29 (2H, d, Jꢁ8.1 Hz), 7.90
(2H, d, Jꢁ8.1 Hz), 8.56 (2H, d, Jꢁ5.9 Hz).
br s), 7.22 (1H, s), 7.41 (2H, d, Jꢁ8.1 Hz), 7.99 (2H, d, Jꢁ6.0 Hz), 8.03 (2H,
d, Jꢁ8.1 Hz), 8.85 (2H, d, Jꢁ6.0 Hz).
1-(3-Methylphenyl)-2-(4-pyridyl)ethanone (4g) This compound was
prepared from 2e as described in the synthesis of 4a as a solid, yield 65%,
mp 115—116 °C (ethyl acetate–isopropyl ether), H-NMR (CDCl3) d: 2.43
(3H, s), 4.28 (2H, s), 7.20 (2H, dd, Jꢁ4.4, 1.8 Hz), 7.32—7.46 (2H, m),
7.76—7.83 (2H, m), 8.56 (2H, dd, Jꢁ4.4, 1.8 Hz).
2-Bromo-1-(3-methylphenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5g) This compound was prepared from 4g as described in the synthesis of
5a as a crude oil and this compound was used for the next reaction without
further purification.
2-Bromo-1-(2-methylphenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5h) This compound was prepared from 4h as described in the synthesis of
5a as a solid, yield 77%, 1H-NMR (DMSO-d6) d: 2.43 (3H, s), 5.34 (1H,
1
1-(2-Methylphenyl)-2-(4-pyridyl)ethanone (4h) This compound was
prepared from 2f as described in the synthesis of 4a as an oil, yield 58%, 1H-
NMR (CDCl3) d: 2.48 (3H, s), 4.23 (2H, s), 7.19 (2H, d, Jꢁ6.2 Hz), 7.24— br s), 7.20 (1H, s), 7.34—7.58 (3H, m), 8.03—8.14 (3H, m), 8.92 (2H, d,
7.47 (3H, m), 7.73 (1H, d, Jꢁ7.7 Hz), 8.56 (2H, d, Jꢁ6.2 Hz).
Jꢁ6.6 Hz).
1-(4-Chlorophenyl)-2-(4-pyridyl)ethanone (4i) This compound was
prepared from 2g as described in the synthesis of 4a as a solid, yield 56%,
mp 93—94 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: 4.26 (2H, s),
7.19 (2H, d, Jꢁ6.2 Hz), 7.47 (2H, d, Jꢁ8.6 Hz), 7.94 (2H, d, Jꢁ8.6 Hz),
8.58 (2H, d, Jꢁ6.2 Hz).
2-Bromo-1-(4-chlorophenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5i) This compound was prepared from 4i as described in the synthesis of
5a as a solid, yield 93%, H-NMR (DMSO-d6) d: 4.78 (1H, br s), 7.26 (1H,
s), 7.70 (2H, d, Jꢁ8.6 Hz), 8.08 (2H, d, Jꢁ6.6 Hz), 8.15 (2H, d, Jꢁ8.6 Hz),
8.91 (2H, d, Jꢁ6.6 Hz).
1
1-(3-Chlorophenyl)-2-(4-pyridyl)ethanone (4j) This compound was
prepared from 2h as described in the synthesis of 4a as a solid, yield 75%,
mp 79—80 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: 4.27 (2H, s),
7.19 (2H, d, Jꢁ6.0 Hz), 7.44 (1H, dd, Jꢁ7.9, 7.7 Hz), 7.58 (1H, ddd, Jꢁ7.9,
1.8, 1.0 Hz), 7.87 (1H, ddd, Jꢁ7.7, 1.8, 1.0 Hz), 7.97 (1H, t, Jꢁ1.8 Hz), 8.58
(2H, d, Jꢁ6.0 Hz).
1-(2-Chlorophenyl)-2-(4-pyridyl)ethanone (4k) This compound was
prepared from 2i as described in the synthesis of 4a as an oil, yield 79%, 1H-
NMR (CDCl3) d: 4.28 (2H, s), 7.20 (2H, d, Jꢁ6.2 Hz), 7.28—7.39 (1H, m),
7.41—7.48 (3H, m), 8.56 (2H, d, Jꢁ6.2 Hz).
2-Bromo-1-(3-chlorophenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5j) This compound was prepared from 4j as described in the synthesis of
5a as a solid, 1H-NMR (DMSO-d6) d: 5.75 (1H, br s), 7.32 (1H, s), 7.65
(1H, t, Jꢁ8.1 Hz), 7.77—7.85 (1H, m), 8.05—8.12 (1H, m), 8.13—8.21
(3H, m), 8.95 (2H, d, Jꢁ6.6 Hz).
2-Bromo-1-(2-chlorophenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5k) This compound was prepared from 4k as described in the synthesis of
1
5a as a solid, yield 65%, H-NMR (DMSO-d6) d: 5.68 (1H, br s), 7.44 (1H,
s), 7.50—7.66 (3H, m), 7.90—8.06 (3H, m), 8.90 (2H, d, Jꢁ6.6 Hz).
2-Bromo-1-(4-fluorophenyl)-2-(4-pyridyl)ethanone Hydrobromide (5l)
This compound was prepared from 4l as described in the synthesis of 5a as a
solid, yield 81%, 1H-NMR (DMSO-d6) d: 4.65 (1H, br s), 7.19 (1H, s), 7.43
(2H, t, Jꢁ8.8 Hz), 7.81—7.90 (2H, m), 8.19 (2H, dd, Jꢁ8.8, 5.4 Hz), 8.74—
8.80 (2H, m).
1-(4-Fluorophenyl)-2-(4-pyridyl)ethanone (4l) This compound was
prepared from 2j as described in the synthesis of 4a as a solid, yield 56%,
mp 93—94 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: 4.27 (2H, s),
7.12—7.21 (4H, m), 8.00—8.07 (2H, m), 8.56—8.59 (2H, m).
1-(3-Fluorophenyl)-2-(4-pyridyl)ethanone (4m) This compound was
prepared from 2k as described in the synthesis of 4a as an amorphous solid,
2-Bromo-1-(3-fluorophenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5m) This compound was prepared from 4m as described in the synthesis
of 5a as a solid, yield 66%, 1H-NMR (DMSO-d6) d: 5.19 (1H, br s), 7.05
(1H, s), 7.58—7.75 (2H, m), 7.95—8.07 (2H, m), 8.26 (2H, d, Jꢁ6.2 Hz),
1
yield 80%, H-NMR (CDCl3) d: 4.28 (2H, s), 7.20 (2H, d, Jꢁ6.2 Hz), 7.33
(1H, ddd, Jꢁ8.1, 2.6, 1.1 Hz), 7.49 (1H, ddd, Jꢁ8.1, 7.7, 5.5 Hz), 7.68 (1H,
ddd, Jꢁ9.5, 2.6, 1.5 Hz), 7.79 (1H, ddd, Jꢁ7.7, 1.5, 1.1 Hz), 8.58 (2H, d, 9.02 (2H, d, Jꢁ6.2 Hz).
Jꢁ6.2 Hz).
2-Bromo-1-[4-(1,1-dimethylethyl)phenyl]-2-(4-pyridyl)ethanone Hy-
1-[4-(1,1-Dimethylethyl)phenyl]-2-(4-pyridyl)ethanone (4n) This
drobromide (5n) This compound was prepared from 4n as described in
compound was prepared from 2l as described in the synthesis of 4a as a the synthesis of 5a as an amorphous solid, yield 96%, 1H-NMR (DMSO-d6)
solid, yield 43%, mp 75—76 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: 1.33 (9H, s), 5.81 (1H, br s), 7.28 (1H, s), 7.62 (2H, d, Jꢁ8.4 Hz), 8.09
d: 1.34 (9H, s), 4.27 (2H, s), 7.21 (2H, d, Jꢁ6.2 Hz), 7.50 (2H, d,
Jꢁ8.6 Hz), 7.94 (2H, d, Jꢁ8.6 Hz), 8.56 (2H, d, Jꢁ6.2 Hz).
(2H, d, Jꢁ8.4 Hz), 8.14 (2H, d, Jꢁ6.6 Hz), 8.93 (2H, d, Jꢁ6.6 Hz).
[4-(4-Methoxyphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6a) Thi-
2-Bromo-1-(4-methoxyphenyl)-2-(4-pyridyl)ethanone Hydrobromide ourea (2.2 g, 31 mmol) was added to a mixture of 5a (11 g, 28 mmol) in ace-
(5a) Bromine (1.6 ml, 31 mmol) was added dropwise to a solution of 4a tonitrile (170 ml), and then triethylamine (4.1 ml, 30 mmol) was added to the
(7.0 g, 31 mmol) in acetic acid (30 ml) and the mixture was stirred for 3 h at
80 °C. The solvent was removed in vacuo and ethyl acetate was added to the moved in vacuo and aqueous sodium hydrogen carbonate was added to the
residue. The resulting crystal was collected by filtration and washed with residue. The precipitate was collected by filtration and the resulting solid
ethyl acetate to afford 11 g (yield 93%) of 5a as a solid, H-NMR (DMSO- was washed with water and then ether. The crude crystal was recrystallized
mixture. The resulting solution was refluxed for 3 h. The solvent was re-
1
d6) d: 3.89 (3H, s), 6.02 (1H, br s), 7.13 (2H, d, Jꢁ9.2 Hz), 7.28 (1H, s),
8.13 (2H, d, Jꢁ9.2 Hz), 8.18 (2H, d, Jꢁ6.6 Hz), 8.95 (2H, d, Jꢁ6.6 Hz).
2-Bromo-1-(4-methoxyphenyl)-2-(3-pyridyl)ethanone Hydrobromide Jꢁ6.2 Hz), 7.34 (2H, d, Jꢁ8.8 Hz), 7.38 (2H, br s), 8.38 (2H, d, Jꢁ6.2 Hz).
from ethanol to afford 5.5 g (yield 68%) of 6a as a solid, mp 282—284 °C,
1H-NMR (DMSO-d6) d: 3.77 (3H, s), 6.90 (2H, d, Jꢁ8.8 Hz), 7.08 (2H, d,
(5b) This compound was prepared from 4b as described in the synthesis of
5a as a solid, yield 89%, H-NMR (CDCl3) d: 3.87 (3H, s), 4.60 (1H, br s),
7.11 (2H, d, Jꢁ9.0 Hz), 7.16 (1H, s), 7.61—7.69 (1H, m), 8.11 (2H, d,
Jꢁ9.0 Hz), 8.20 (1H, d, Jꢁ8.1 Hz), 8.65 (1H, dd, Jꢁ6.6, 4.8 Hz), 8.86 (1H,
d, Jꢁ2.2 Hz).
Anal. Calcd for C15H13N3OS: C, 63.58; H, 4.62; N, 14.83. Found: C, 63.37;
H, 4.71; N, 14.80.
1
[4-(4-Methoxyphenyl)-5-(3-pyridyl)-1,3-thiazol-2-yl]amine (6b) This
compound was prepared from 5b as described in the synthesis of 6a as a
1
solid, yield 90%, mp 265—266 °C (pyridine), H-NMR (DMSO-d6) d: 3.75
2-Bromo-1-(4-methoxyphenyl)-2-(2-pyridyl)ethanone Hydrobromide (3H, s), 6.86 (2H, d, Jꢁ8.8 Hz), 7.20—7.36 (5H, m), 7.55—7.63 (1H, m),
(5c) This compound was prepared from 4c as described in the synthesis of
8.35—8.43 (2H, m). Anal. Calcd for C15H13N3OS: C, 63.58; H, 4.62; N,
5a as a solid, yield 44%, 1H-NMR (CDCl3) d: 3.82 (3H, s), 7.01 (2H, d, 14.83. Found: C, 63.40; H, 4.86; N, 14.81.
Jꢁ9.2 Hz), 7.16 (1H, s), 7.37 (1H, dd, Jꢁ7.3, 4.9 Hz), 7.56 (1H, br s), 7.74
(1H, d, Jꢁ7.7 Hz), 7.91 (1H, dd, Jꢁ7.7, 7.3 Hz), 7.98 (2H, d, Jꢁ9.2 Hz),
8.51 (1H, d, Jꢁ4.8 Hz).
[4-(4-Methoxyphenyl)-5-(2-pyridyl)-1,3-thiazol-2-yl]amine (6c) This
compound was prepared from 5c as described in the synthesis of 6a as a
solid, yield 55%, mp 217—218 °C (pyridine), 1H-NMR (CDCl3) d: 3.79
2-Bromo-1-(3-methoxyphenyl)-2-(4-pyridyl)ethanone Hydrobromide (3H, s), 6.95 (2H, d, Jꢁ8.8 Hz), 7.00—7.09 (2H, m), 7.09 (2H, br s), 7.39
(5d) This compound was prepared from 4d as described in the synthesis of
5a as a crude oil and this compound was used for the next reaction without
further purification.
(2H, d, Jꢁ8.8 Hz), 7.45—7.53 (1H, m), 8.35—8.43 (1H, d, Jꢁ4.8 Hz). Anal.
Calcd for C15H13N3OS: C, 63.58; H, 4.62; N, 14.83. Found: C, 63.35; H,
4.59; N, 14.73.
2-Bromo-1-(2-methoxyphenyl)-2-(4-pyridyl)ethanone Hydrobromide
(5e) This compound was prepared from 4e as described in the synthesis of
[4-(3-Methoxyphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6d) This
compound was prepared from 5d as described in the synthesis of 6a as a
1
5a as a solid, yield 57%, 1H-NMR (DMSO-d6) d: 3.90 (3H, s), 4.57 (1H, solid, yield 37%, mp 232—234 °C (pyridine), H-NMR (DMSO-d6) d: 3.69
br s), 6.92 (1H, s), 7.09 (1H, dd, Jꢁ7.7, 7.3 Hz), 7.20 (1H, d, Jꢁ8.4 Hz),
7.63 (1H, ddd, Jꢁ8.4, 7.3, 1.5 Hz), 7.71 (1H, dd, Jꢁ7.7, 1.5 Hz), 8.00 (2H,
d, Jꢁ6.0 Hz), 8.87 (2H, d, Jꢁ6.6 Hz).
(3H, s), 6.87—6.97 (3H, m), 7.09 (2H, d, Jꢁ6.2 Hz), 7.24 (1H, dd, Jꢁ8.4,
7.3 Hz), 7.43 (2H, br s), 8.40 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for
C15H13N3OS: C, 63.58; H, 4.62; N, 14.83. Found: C, 63.33; H, 4.70; N,
2-Bromo-1-(4-methylphenyl)-2-(4-pyridyl)ethanone Hydrobromide 14.78.

416
Vol. 53, No. 4
[4-(2-Methoxyphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6e) This This compound was prepared from 6b as described in the synthesis of 7a as
compound was prepared from 5e as described in the synthesis of 6a as a a solid, yield 82%, mp 119—120 °C (ethanol), 1H-NMR (DMSO-d6) d: 1.66
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solid, yield 61%, mp 213—215 °C (ethanol), H-NMR (DMSO-d6) d: 3.51 (3H, s), 3.82 (3H, s), 6.86 (2H, d, Jꢁ8.8 Hz), 7.26 (1H, dd, Jꢁ8.2, 5.2 Hz),
(3H, s), 6.88 (2H, d, Jꢁ6.2 Hz), 6.95—7.08 (2H, m), 7.26 (1H, dd, Jꢁ7.3, 7.40 (2H, d, Jꢁ8.8 Hz), 7.66 (1H, dt, Jꢁ8.2, 3.9 Hz), 8.54 (1H, dd, Jꢁ5.2,
1.8 Hz), 7.34—7.45 (3H, m), 8.28 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for
C15H13N3OS·0.2H2O: C, 62.78; H, 4.71; N, 14.64. Found: C, 62.73; H, 4.82; C17H15N3O2S: C, 62.75; H, 4.65; N, 12.91. Found: C, 62.38; H, 4.32; N,
N, 14.61. 12.67.
[4-(4-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6f) This N-[4-(4-Methoxyphenyl)-5-(2-pyridyl)-1,3-thiazol-2-yl]acetamide (7c)
compound was prepared from 5f as described in the synthesis of 6a as a This compound was prepared from 6c as described in the synthesis of 7a as
1.6 Hz), 8.62 (1H, d, Jꢁ1.6 Hz), 11.51 (1H, br s). Anal. Calcd for
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solid, yield 75%, mp 296—298 °C (pyridine), H-NMR (DMSO-d6) d: 2.32 a solid, yield 29%, mp 230—232 °C (ethanol), 1H-NMR (CDCl3) d: 1.83
(3H, s), 7.07 (2H, d, Jꢁ6.0 Hz), 7.15 (2H, d, Jꢁ8.1 Hz), 7.35 (2H, d, (3H, s), 3.85 (3H, s), 6.90—6.95 (2H, m), 7.08—7.14 (1H, m), 7.20—7.25
Jꢁ8.1 Hz), 7.39 (2H, br s), 8.37 (2H, d, Jꢁ6.0 Hz). Anal. Calcd for (1H, m), 7.44—7.51 (3H, m), 8.58—8.61 (1H, m), 10.78 (1H, br s). Anal.
C15H13N3S: C, 67.39; H, 4.90; N, 15.72. Found: C, 67.13; H, 4.76; N, 15.63.
[4-(3-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6g) This
Calcd for C17H15N3O2S: C, 62.75; H, 4.65; N, 12.91. Found: C, 62.57; H,
4.60; N, 12.99.
compound was prepared from 5g as described in the synthesis of 6a as a
N-[4-(3-Methoxyphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7d)
1
solid, yield 72%, mp 255—258 °C (pyridine), H-NMR (DMSO-d6) d: 2.27 This compound was prepared from 6d as described in the synthesis of 7a as
(3H, s), 7.07 (2H, d, Jꢁ6.2 Hz), 7.10—7.29 (5H, m), 7.40 (1H, s), 8.37 (2H, a solid, yield 70%, mp 234—236 °C (ethanol), 1H-NMR (DMSO-d6) d: 2.19
d, Jꢁ6.2 Hz). Anal. Calcd for C15H13N3S: C, 67.39; H, 4.90; N, 15.72. (3H, s), 3.68 (3H, s), 6.89—7.02 (3H, m), 7.22—7.33 (3H, m), 8.52 (2H, d,
Found: C, 67.26; H, 4.83; N, 15.60.
[4-(2-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6h) This
Jꢁ6.2 Hz), 12.46 (1H, br s). Anal. Calcd for C17H15N3O2S·0.3H2O: C,
61.73; H, 4.75; N, 12.70. Found: C, 61.99; H, 5.10; N, 12.38.
compound was prepared from 5h as described in the synthesis of 6a as a
N-[4-(2-Methoxyphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7e)
1
solid, yield 42%, mp 235—238 °C (ethyl acetate), H-NMR (DMSO-d6) d: This compound was prepared from 6e as described in the synthesis of 7a as
2.08 (3H, s), 6.80 (2H, d, Jꢁ6.2 Hz), 7.12—7.34 (4H, m), 7.47 (2H, br s), a solid, yield 54%, mp 259—261 °C (ethanol), 1H-NMR (DMSO-d6) d: 2.19
8.26 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for C15H13N3S·0.2H2O: C, 66.49; H, (3H, s), 3.45 (3H, s), 6.97—7.12 (4H, m), 7.28—7.47 (2H, m), 8.41 (2H, d,
4.98; N, 15.51. Found: C, 66.82; H, 5.04; N, 15.20.
Jꢁ6.2 Hz), 12.40 (1H, br s). Anal. Calcd for C17H15N3O2S: C, 62.75; H,
4.65; N, 12.91. Found: C, 62.60; H, 4.65; N, 12.90.
N-[4-(4-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7f)
[4-(4-Chlorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6i) This
compound was prepared from 5i as described in the synthesis of 6a as a
solid, yield 73%, mp ꢀ300 °C (pyridine), 1H-NMR (DMSO-d6) d: 7.10 (2H, This compound was prepared from 6f as described in the synthesis of 7a as a
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d, Jꢁ6.2 Hz), 7.40 (4H, s), 7.46 (2H, br s), 8.42 (2H, d, Jꢁ6.2 Hz). Anal.
solid, yield 54%, mp 308—309 °C (ethanol), H-NMR (DMSO-d6) d: 2.19
Calcd for C14H10ClN3S: C, 58.43; H, 3.50; N, 14.60. Found: C, 58.41; H, (3H, s), 2.33 (3H, s), 7.18 (2H, d, Jꢁ7.9 Hz), 7.26 (2H, d, Jꢁ6.0 Hz), 7.33
3.57; N, 14.60.
(2H, d, Jꢁ7.9 Hz), 8.50 (2H, d, Jꢁ6.0 Hz), 12.44 (1H, br s). Anal. Calcd for
C17H15N3OS: C, 66.00; H, 4.89; N, 13.58. Found: C, 65.96; H, 4.76; N,
13.42.
[4-(3-Chlorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6j) This
compound was prepared from 5j as described in the synthesis of 6a as a
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solid, yield 60%, mp 256—258 °C (pyridine), H-NMR (DMSO-d6) d: 7.12
N-[4-(3-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7g)
(2H, d, Jꢁ6.2 Hz), 7.27—7.42 (3H, m), 7.44—7.51 (3H, m), 8.43 (2H, d, This compound was prepared from 6g as described in the synthesis of 7a as
Jꢁ6.2 Hz). Anal. Calcd for C14H10ClN3S: C, 58.43; H, 3.50; N, 14.60. a solid, yield 68%, mp 287—289 °C (ethanol), 1H-NMR (DMSO-d6) d: 2.19
Found: C, 58.35; H, 3.58; N, 14.51.
[4-(2-Chlorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine (6k) This
(3H, s), 2.28 (3H, s), 7.14—7.35 (6H, m), 8.50 (2H, d, Jꢁ6.2 Hz), 12.45
(1H, br s). Anal. Calcd for C17H15N3OS: C, 66.00; H, 4.89; N, 13.58. Found:
compound was prepared from 5k as described in the synthesis of 6a as a C, 66.06; H, 4.78; N, 13.68.
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solid, yield 24%, mp 232—235 °C (ethanol), H-NMR (DMSO-d6) d: 7.14
N-[4-(2-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7h)
(2H, d, Jꢁ5.7 Hz), 7.43—7.68 (4H, m), 8.15 (2H, br s), 8.46 (2H, d, This compound was prepared from 6h as described in the synthesis of 7a as
Jꢁ5.7 Hz). Anal. Calcd for C14H10ClN3S: C, 58.43; H, 3.50; N, 14.60. a solid, yield 56%, mp 272—274 °C (ethanol), 1H-NMR (DMSO-d6) d: 2.06
Found: C, 58.23; H, 3.72; N, 14.38.
(3H, s), 2.20 (3H, s), 7.03 (2H, d, Jꢁ6.0 Hz), 7.15—7.42 (4H, m), 8.39 (2H,
4-(3-Fluorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-ylamine (6l) This d, Jꢁ6.0 Hz), 12.39 (1H, br s). Anal. Calcd for C17H15N3OS: C, 66.00; H,
compound was prepared from 5m as described in the synthesis of 6a as a 4.89; N, 13.58. Found: C, 65.87; H, 4.84; N, 13.63.
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solid, yield 86%, mp 263—264 °C (ethanol), H-NMR (DMSO-d6) d: 7.11
N-[4-(4-Chlorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7i)
(2H, d, Jꢁ6.3 Hz), 7.16—7.46 (6H, m), 8.43 (2H, d, Jꢁ6.3 Hz). Anal. Calcd This compound was prepared from 6i as described in the synthesis of 7a as a
for C14H10FN3S: C, 61.98; H, 3.72; N, 15.49. Found: C, 61.78; H, 3.60; N, solid, yield 73%, mp 317—320 °C (ethanol), H-NMR (DMSO-d6) d: 2.20
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15.20.
(3H, s), 7.28 (2H, d, Jꢁ6.0 Hz), 7.45 (4H, s), 8.53 (2H, d, Jꢁ6.0 Hz), 12.49
4-[4-(1,1-Dimethylethyl)phenyl]-5-(4-pyridyl)-1,3-thiazol-2-ylamine (1H, br s). Anal. Calcd for C16H12ClN3OS·0.2H2O: C, 57.64; H, 3.75; N,
(6m) This compound was prepared from 5n as described in the synthesis
of 6a as a solid, yield 69%, mp 254—257 °C (ethanol), H-NMR (DMSO-
12.60. Found: C, 57.87; H, 3.80; N, 12.41.
N-[4-(3-Chlorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7j)
1
d6) d: 1.29 (9H, s), 7.10 (2H, d, Jꢁ6.2 Hz), 7.34 (6H, s), 8.38 (2H, d, This compound was prepared from 6j as described in the synthesis of 7a as a
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Jꢁ6.2 Hz). Anal. Calcd for C18H19N3S·0.5H2O: C, 67.89; H, 6.33; N, 13.20. solid, yield 57%, mp 290—293 °C (ethanol), H-NMR (DMSO-d6) d: 2.20
Found: C, 67.77; H, 6.29; N, 12.86.
(3H, s), 7.30 (2H, d, Jꢁ6.2 Hz), 7.32—7.46 (3H, m), 7.50 (1H, s), 8.55 (2H,
N-Methyl-[4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]amine d, Jꢁ6.2 Hz), 12.49 (1H, br s). Anal. Calcd for C16H12ClN3OS: C, 58.27; H,
(6n) This compound was prepared from 5g and N-methylthiourea as de- 3.67; N, 12.74. Found: C, 58.10; H, 3.72; N, 12.75.
scribed in the synthesis of 6a as a solid, yield 67%, mp 199—202 °C
N-[4-(2-Chlorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7k)
This compound was prepared from 6k as described in the synthesis of 7a as
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(ethanol), H-NMR (CDCl3) d: 2.34 (3H, s), 2.81 (3H, d, Jꢁ4.4 Hz), 6.79
(1H, br s), 7.07 (2H, d, Jꢁ6.2 Hz), 7.16—7.25 (3H, m), 7.33 (1H, s), 8.39 a solid, yield 47%, mp 292—293 °C (ethanol), 1H-NMR (DMSO-d6) d: 2.20
(2H, d, Jꢁ6.2 Hz). Anal. Calcd for C16H15N3S: C, 68.30; H, 5.37; N, 14.93. (3H, s), 7.06 (2H, d, Jꢁ6.2 Hz), 7.40—7.62 (4H, m), 8.38 (2H, d,
Found: C, 68.23; H, 5.32; N, 15.06.
Jꢁ6.2 Hz), 12.47 (1H, br s). Anal. Calcd for C16H12ClN3OS: C, 58.27; H,
N-[4-(4-Methoxyphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7a) 3.67; N, 12.74. Found: C, 58.27; H, 3.53; N, 12.75.
Acetyl chloride (1.7 g, 21 mmol) was added to a solution of 6a (4.0 g,
14 mmol) and DMAP (0.52 g, 4.2 mmol) in DMA (40 ml), and the resulting
mixture was stirred at 80 °C for 14 h. Aqueous sodium hydrogen carbonate
N-[4-(3-Fluorophenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]acetamide (7l)
This compound was prepared from 6l as described in the synthesis of 7a as a
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solid, yield 82%, mp 326—328 °C (ethanol), H-NMR (DMSO-d6) d: 2.20
was added to the reaction mixture and extracted with ethyl acetate. The ex- (3H, s), 7.16—7.46 (6H, m), 8.54 (2H, d, Jꢁ5.8 Hz), 12.46 (1H, br s). Anal.
tracts were washed with brine, dried and concentrated to give a solid. This
Calcd for C16H12FN3OS: C, 61.33; H, 3.86; N, 13.41. Found: C, 61.24; H,
was recrystallized from ethanol to afford 4.2 g (yield 92%) of 7a as a solid, 3.91; N, 13.14.
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mp 282—284 °C, H-NMR (DMSO-d6) d: 2.19 (3H, s), 3.78 (3H, s), 6.93
(2H, d, Jꢁ8.8 Hz), 7.26 (2H, d, Jꢁ6.2 Hz), 7.37 (2H, d, Jꢁ8.8 Hz), 8.50
N-[4-[4-(1,1-Dimethylethyl)phenyl]-5-(4-pyridyl)-1,3-thiazol-2-yl]ac-
etamide (7m) This compound was prepared from 6m as described in the
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(2H, d, Jꢁ6.2 Hz), 12.42 (1H, br s). Anal. Calcd for C17H15N3O2S: C, 62.75; synthesis of 7a as a solid, yield 50%, mp 280—281 °C (ethanol), H-NMR
H, 4.65; N, 12.91. Found: C, 62.71; H, 4.77; N, 13.18. (DMSO-d6) d: 1.29 (9H, s), 2.20 (3H, s), 7.28 (2H, d, Jꢁ6.0 Hz), 7.38 (4H,
N-[4-(4-Methoxyphenyl)-5-(3-pyridyl)-1,3-thiazol-2-yl]acetamide (7b) s), 8.51 (2H, d, Jꢁ6.0 Hz), 12.41 (1H, br s). Anal. Calcd for C20H21N3OS: C,

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68.35; H, 6.02; N, 11.96. Found: C, 68.34; H, 5.99; N, 11.95.
N, 8.34.
N-Methyl-N-[4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]ac-
2-(2-Methylphenyl)-4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazole (8e)
etamide (7n) This compound was prepared from 6n as described in the
This compound was prepared from 5g and 13c as described in the synthesis
1
synthesis of 7a as a solid, yield 64%, mp 169—170 °C (ethanol), H-NMR of 8a as a paste, yield 68%, 1H-NMR (CDCl3) d: 2.34 (3H, s), 2.70 (3H, s),
(CDCl3) d: 2.33 (3H, s), 2.46 (3H, s), 3.79 (3H, s), 7.12—7.29 (5H, m), 7.37 7.14—7.38 (8H, m), 7.46 (1H, s), 7.81 (1H, ddd, Jꢁ6.6, 1.8, 1.1 Hz), 8.56
(1H, s), 8.50 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for C18H17N3OS: C, 66.85; H, (2H, d, Jꢁ6.0 Hz). Anal. Calcd for C22H18N2S: C, 77.16; H, 5.30; N, 8.18.
5.30; N, 12.99. Found: C, 66.88; H, 5.26; N, 12.98.
Found: C, 76.95; H, 5.07; N, 8.05.
4-(Methylthio)benzenecarbothioamide (13a) O,O-Diethyl hydrogen
dithiophosphate (15 ml, 88 mmol) was added to a solution of 4-methylthi-
obenzonitrile (12 g, 80 mmol) in a solution of 4 N hydrogen chloride in ethyl
acetate (130 ml) and the mixture was stirred for 22 h at room temperature.
The reaction mixture was washed with brine (100 ml) twice and aqueous
sodium hydrogen carbonate. The organic phase was dried and concentrated
2-(3-Methylphenyl)-4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazole (8f)
This compound was prepared from 5g and 13d as described in the synthesis
of 8a as a solid, yield 76%, mp 86—87 °C (ethyl acetate–isopropyl ether),
1H-NMR (CDCl3) d: 2.36 (3H, s), 2.44 (3H, s), 7.17—7.31 (6H, m), 7.36
(1H, dd, Jꢁ7.7, 7.3 Hz), 7.46 (1H, s), 7.80 (1H, d, Jꢁ7.3 Hz), 7.87 (1H, s),
8.54 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for C22H18N2S: C, 77.16; H, 5.30; N,
to give a residue. This was recrystallized from ethyl acetate to afford 10 g 8.18. Found: C, 77.19; H, 5.37; N, 8.21.
(yield 67%) of 13a as a solid, mp 176—178 °C, 1H-NMR (DMSO-d6) d:
2.51 (3H, s), 7.27 (2H, d, Jꢁ8.4 Hz), 7.88 (2H, d, Jꢁ8.4 Hz), 9.42 (1H, br s),
9.77 (1H, br s).
2-(4-Methylphenyl)-4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazole (8g)
This compound was prepared from 5g and 13e as described in the synthesis
of 8a as a solid, yield 72%, mp 138—139 °C (ethyl acetate), 1H-NMR
(CDCl3) d: 2.35 (3H, s), 2.42 (3H, s), 7.14—7.32 (7H, m), 7.46 (1H, s), 7.91
Methyl 4-(Aminothioxomethyl)benzoate (13b) This compound was
prepared from methyl 4-cyanobenzoate as described in the synthesis of 13a (2H, d, Jꢁ8.1 Hz), 8.54 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for C22H18N2S: C,
as a solid, yield 85%, mp 191—192 °C (ethyl acetate–hexane), 1H-NMR 77.16; H, 5.30; N, 8.18. Found: C, 76.96; H, 5.38; N, 8.13.
(CDCl3) d: 3.95 (3H, s), 7.21 (1H, br s), 7.67 (1H, br s), 7.91 (2H, d,
Jꢁ8.6 Hz), 8.07 (2H, d, Jꢁ8.6 Hz).
4-[4-(3-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]phenol (8h)
This compound was prepared from 5g and 13f as described in the synthesis
1
2-Methylbenzenecarbothioamide (13c) This compound was prepared
from 2-methylbenzonitrile as described in the synthesis of 13a as an oil,
of 8a as a solid, yield 78%, mp 248—249 °C (THF), H-NMR (DMSO-d6)
d: 2.30 (3H, s), 7.00 (2H, d, Jꢁ8.6 Hz), 7.17—7.28 (3H, m), 7.30 (2H, d,
yield 54%, 1H-NMR (CDCl3) d: 2.37 (3H, s), 6.88 (1H, br s), 7.06—7.23 Jꢁ5.7 Hz), 7.39 (1H, s), 7.84 (2H, d, Jꢁ8.6 Hz), 8.54 (2H, d, Jꢁ5.7 Hz),
(3H, m), 7.24—7.31 (1H, m), 7.88 (1H, br s).
10.13 (1H, s). Anal. Calcd for C21H16N2OS: C, 73.23; H, 4.68; N, 8.13.
Found: C, 73.34; H, 4.61; N, 7.90.
4-(3-Methylphenyl)-2-(4-methylthiophenyl)-5-(4-pyridyl)-1,3-thiazole
3-Methylbenzenecarbothioamide (13d) This compound was prepared
from 3-methylbenzonitrile as described in the synthesis of 13a as a solid,
yield 72%, mp 88—89 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: 2.40 (8i) This compound was prepared from 5g and 13a as described in the syn-
(3H, s), 7.18 (1H, br s), 7.24—7.36 (2H, m), 7.62 (1H, dt, Jꢁ6.2, 1.8 Hz), thesis of 8a as a solid, yield 45%, mp 101—102 °C (ethyl acetate–isopropyl
7.70 (1H, br s), 7.88 (1H, br s).
ether), 1H-NMR (CDCl3) d: 2.36 (3H, s), 2.54 (3H, s), 7.16—7.34 (7H, m),
7.45 (1H, s), 7.94 (2H, d, Jꢁ8.8 Hz), 8.54 (2H, d, Jꢁ6.2 Hz). Anal. Calcd
for C22H18N2S2: C, 70.55; H, 4.84; N, 7.48. Found: C, 70.55; H, 4.96; N,
4-Methylbenzenecarbothioamide (13e) This compound was prepared
from 4-methylbenzonitrile as described in the synthesis of 13a as a solid,
yield 62%, mp 172—174 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: 7.74.
2.39 (3H, s), 7.15 (1H, br s), 7.21 (2H, d, Jꢁ8.1 Hz), 7.57 (1H, br s), 7.79
Methyl 4-[4-(3-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]benzoate
(2H, d, Jꢁ8.1 Hz).
(8j) This compound was prepared from 5g and 13b as described in the
synthesis of 8a as a solid, yield 58%, mp 152—153 °C (ethanol), H-NMR
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4-Hydroxybenzenecarbothioamide (13f) This compound was prepared
from 4-hydroxybenzonitrile as described in the synthesis of 13a as a solid, (CDCl3) d: 2.36 (3H, s), 3.96 (3H, s), 7.19—7.27 (3H, m), 7.28 (2H, d,
yield 39%, mp 206—207 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) d: Jꢁ6.2 Hz), 7.46 (1H, s), 8.09 (2H, d, Jꢁ8.8 Hz), 8.15 (2H, d, Jꢁ8.8 Hz),
6.75 (2H, d, Jꢁ8.8 Hz), 7.86 (2H, d, Jꢁ8.8 Hz), 9.21 (1H, br s), 9.52 (1H,
br s), 10.09 (1H, br s).
8.57 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for C23H18N2O2S: C, 71.48; H, 4.69; N,
7.25. Found: C, 71.39; H, 4.60; N, 6.99.
2,2-Dimethylpropanethioamide (13g) This compound was prepared
4-(4-Fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyridyl)-1,3-thiazole
from 2,2-dimethylpropionitrile as described in the synthesis of 13a as a (8k) This compound was prepared from 5l and 13a as described in the
solid, yield 19%, mp 117—119 °C (ethyl acetate–hexane), 1H-NMR (CDCl3) synthesis of 8a as a solid, yield 84%, mp 115—118 °C (ethyl acetate–iso-
d: 1.38 (9H, s), 7.04 (1H, br s), 7.86 (1H, br s).
2-Ethyl-4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazole (8a) Thiopropi- 7.25 (2H, d, Jꢁ6.2 Hz), 7.30 (2H, d, Jꢁ8.2 Hz), 7.55 (2H, dd, Jꢁ8.8,
propyl ether), 1H-NMR (CDCl3) d: 2.54 (3H, s), 7.06 (2H, t, Jꢁ8.8 Hz),
onamide (0.53 g, 5.9 mmol) was added to a suspension of 5g (2.0 g,
5.4 mmol) in DMF (6.0 ml) and the resulting mixture was stirred at room
temperature for 14 h. Aqueous sodium hydrogen carbonate was added to the
5.5 Hz), 7.92 (2H, d, Jꢁ8.2 Hz), 8.57 (2H, d, Jꢁ6.2 Hz). Anal. Calcd for
C21H15FN2S2: C, 66.64; H, 3.99; N, 7.40. Found: C, 66.56; H, 4.05; N, 7.33.
4-(3-Methylphenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1,3-thia-
reaction mixture and extracted with ethyl acetate. The extracts were washed zole (9) A solution of potassium persulfate (0.64 g, 2.4 mmol) in water
with brine, dried, and concentrated to give a solid. This was recrystallized
(20 ml) was added to a solution of 8i (0.80 g, 2.1 mmol) in acetic acid
from ethanol to afford 8.9 g (yield 59%) of 8a as a solid, mp 56—58 °C, 1H- (30 ml) and the mixture was stirred for 14 h at room temperature. The sol-
NMR (CDCl3) d: 1.46 (3H, t, Jꢁ7.6 Hz), 2.33 (3H, s), 3.09 (2H, q, vent was removed in vacuo. Aqueous sodium hydrogen carbonate was added
Jꢁ7.6 Hz), 7.11—7.24 (5H, m), 7.37 (1H, s), 8.51 (2H, d, Jꢁ6.2 Hz). Anal. to the reaction mixture and extracted with ethyl acetate. The extracts were
Calcd for C17H16N2S: C, 72.82; H, 5.75; N, 9.99. Found: C, 72.63; H, 5.94; washed with water, dried, and concentrated to give a crude crystal. This was
N, 9.90.
recrystallized from ethyl acetate to afford 0.48 g (1.2 mmol, yield 58%) of 9
2-(1,1-Dimethylethyl)-4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazole as a solid, mp 188—189 °C, 1H-NMR (DMSO-d6) d: 2.37 (3H, s), 2.79 (3H,
(8b) This compound was prepared from 5g and 13g as described in the
synthesis of 8a as a solid, yield 53%, mp 140—142 °C (ethyl acetate), H-
s), 7.20—7.32 (5H, m), 7.46 (1H, s), 7.76 (2H, d, Jꢁ8.6 Hz), 8.19 (2H, d,
Jꢁ8.6 Hz), 8.57 (2H, d, Jꢁ8.6 Hz). Anal. Calcd for C22H18N2OS2: C, 67.66;
1
NMR (CDCl3) d: 1.51 (9H, s), 2.33 (3H, s), 7.14—7.22 (5H, m), 7.38 (1H, H, 4.65; N, 7.17. Found: C, 67.36; H, 4.73; N, 7.11.
s), 8.49—8.52 (2H, m). Anal. Calcd for C19H20N2S: C, 73.99; H, 6.54; N,
9.08. Found; C, 73.65; H, 6.44; N, 9.09.
4-(3-Methylphenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyridyl)-1,3-thia-
zole (10a) To a solution of 8i (0.80 g, 2.1 mmol) in DMF (8.0 ml) was
2-Methyl-4-(3-methylphenyl)-5-(4-pyridyl)-1,3-thiazole (8c) This added mCPBA (0.90 g, 3.7 mmol) at 0 °C and the mixture was stirred at
compound was prepared from 5g and thioacetamide as described in the syn- room temperature for 3 h. An 8 N aqueous sodium hydroxide was added to
thesis of 8a as a solid, yield 20%, mp 74—75 °C (ethyl acetate–isopropyl the reaction mixture and extracted with ethyl acetate. The extracts were
ether), 1H-NMR (CDCl3) d: 2.33 (3H, s), 2.78 (3H, s), 7.11—7.23 (5H, m), washed with brine, dried, and concentrated to give a residue. The residue
7.37 (1H, s), 8.51 (2H, d, Jꢁ5.9 Hz). Anal. Calcd for C16H14N2S: C, 72.15; was chromatographed on silica gel eluting with hexane–ethyl acetate (3 : 7)
H, 5.30; N, 10.52. Found: C, 72.05; H, 5.18; N, 10.34.
4-(3-Methylphenyl)-2-phenyl-5-(4-pyridyl)-1,3-thiazole (8d) This ether to afford 0.54 g (1.3 mmol, yield 63%) of 10a as a solid, mp 171—
compound was prepared from 5g and thiobenzamide as described in the syn-
to give a crude crystal. This was recrystallized from ethyl acetate–isopropyl
174 °C, 1H-NMR (CDCl3) d: 2.36 (3H, s), 3.11 (3H, s), 7.18—7.32 (5H, m),
thesis of 8a as a solid, yield 74%, mp 118—120 °C (ethyl acetate–isopropyl 7.45 (1H, s), 8.05 (2H, d, Jꢁ8.4 Hz), 8.22 (2H, d, Jꢁ8.4 Hz), 8.58 (2H, d,
1
ether), H-NMR (CDCl3) d: 2.29 (3H, s), 7.14—7.38 (5H, m), 7.43—7.50 Jꢁ6.2 Hz). Anal. Calcd for C22H18N2O2S2: C, 65.00; H, 4.46; N, 6.89.
(3H, m), 7.46 (1H, s), 7.99—8.09 (2H, m), 8.54 (2H, d, Jꢁ4.6 Hz). Anal.
Found: C, 64.96; H, 4.41; N, 7.02.
Calcd for C21H16N2S: C, 76.80; H, 4.91; N, 8.53. Found: C, 77.01; H, 5.14;
4-(4-Fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyridyl)-1,3-thia-

418
Vol. 53, No. 4
zole (10b) This compound was prepared from 8k as described in the syn-
minutes later, blood samples were collected from the eye ground into he-
thesis of 10a as a solid, yield 71%, mp 191—194 °C (ethyl acetate), 1H- parinized tubes. Plasma was obtained by centrifugation and assayed for
NMR (CDCl3) d: 3.12 (3H, s), 7.08 (2H, t, Jꢁ8.8 Hz), 7.28 (2H, d, TNF-a by ELISA using a mouse TNF-a ELISA Kit (Amersham Pharmacia
Jꢁ6.0 Hz), 7.57 (2H, dd, Jꢁ8.8, 5.5 Hz), 8.06 (2H, d, Jꢁ8.8 Hz), 8.22 (2H,
d, Jꢁ8.8 Hz), 8.62 (2H, d, Jꢁ6.0 Hz). Anal. Calcd for C21H15FN2O2S2: C,
61.45; H, 3.68; N, 6.82. Found: C, 61.25; H, 3.69; N, 6.64.
4-[4-(3-Methylphenyl)-5-(4-pyridyl)-1,3-thiazol-2-yl]benzoic Acid (11)
A mixture of 8j (1.0 g, 2.6 mmol) in ethanol (5.2 ml) and 1 N aqueous
Biotech, U.K.).
Anti-collagen Antibody-Induced Arthritis Assay Anti-collagen anti-
body-induced arthritis was induced in 7-week-old female BALB/c mice
(nꢁ6). Monoclonal anti-collagen antibody was injected (2 mg/mouse, i.v.)
on day 0, and then each mouse was injected with LPS (0.025 mg/mouse, i.p.)
sodium hydroxide (5.2 ml, 5.2 mmol) was stirred at room temperature for on day 3. Hind paw thickness was determined on day 0, 3, 7 and 11. Drugs
2 h. The reaction solution was acidified with 2 N hydrochloric acid and the
precipitate was collected by filtration. The crude crystal was washed with
water and ethanol. The crystal was dried to afford 0.72 g (yield 74%) of 11
as a solid, mp 335—336 °C, H-NMR (DMSO-d6) d: 2.32 (3H, s), 7.22—
7.30 (3H, m), 7.37 (2H, d, Jꢁ5.5 Hz), 7.44 (1H, s), 8.09 (2H, d, Jꢁ8.6 Hz),
(10, 30 or 50 mg/kg/day p.o.) and a vehicle (0.5% methyl cellulose solution
in distilled water) were administered from day 0 to day 10.
1
Acknowledgments We thank Dr. Toshimasa Tanaka for his contribution
to the modeling study calculation, Mr. Koji Ohnishi and Mr. Masashi Ya-
8.16 (2H, d, Jꢁ8.6 Hz), 8.60 (2H, d, Jꢁ5.5 Hz). Anal. Calcd for maguchi for pharmacokinetic studies, Mr. Shigeru Morimoto, Mr. Etsuo
C22H16N2O2S: C, 70.95; H, 4.33; N, 7.52. Found: C, 70.91; H, 4.31; N, 7.45. Kotani and Ms. Maki Miyamoto for technical assistance and Dr. Yuji Ishi-
4-[2-Ethyl-4-(3-methylphenyl)-1,3-thiazol-5-yl]pyridine 1-Oxide (12) hara and Dr. Nicholas Hird for reviewing the manuscript.
To a solution of 8a (2.8 g, 10 mmol) in DMF (50 ml) was added mCPBA
(3.0 g, 12 mmol) at 0 °C and the resulting mixture was stirred at room tem-
perature for 14 h. Aqueous sodium hydrogen carbonate was added to the re-
action mixture and extracted with ethyl acetate. The extracts were washed
with brine, dried, and concentrated to give a solid. The crude crystal was
washed with hexane to afford 2.2 g (yield 74%) of 12 as a solid, mp 143—
144 °C, 1H-NMR (CDCl3) d: 1.45 (3H, t, Jꢁ7.6 Hz), 2.35 (3H, s), 3.09 (2H,
q, Jꢁ7.6 Hz), 7.13—7.26 (5H, m), 7.36 (1H, s), 8.06—8.10 (2H, m). Anal.
Calcd for C17H16N2OS: C, 68.89; H, 5.44; N, 9.45. Found: C, 68.90; H, 5.41;
N, 9.62.
Biological Methods. p38 MAP Kinase Assays. Preparation of Re-
combinant p38 cDNAs encoding human p38a19) were isolated by poly-
merase chain reaction (PCR) with primers containing sequences encoding
a FLAG-tag (DYKDDDDK) in the amino-terminal region and subcloned
into pFASTBAC1 (Life Technologies, U.S.A.). cDNAs encoding human
MKK320) and MKK621) were isolated by PCR and subcloned into pT7Blue-T
vector (Novagen, Germany). Ser189 and Thr193 of MKK3 and Ser151 and
Thr155 of MKK6 were substituted with Glu using a QuickChange Site-Di-
rected Mutagenesis Kit (Stratagene, U.S.A.) and subcloned into pFAST-
BAC1 (Life Technologies, U.S.A.). Recombinant baculoviruses were pre-
pared according to the procedure of the Bac-to-Bac baculovirus expression
system (Life Technologies, U.S.A.). For the preparation of active-type p38a,
Sf21 cells were infected with both p38a and constitutive active MKK3 re-
combinant baculoviruses. Infected Sf21 cells were cultured at 28 °C for 72 h,
and then harvested by centrifugation. Cells were lysed and FLAG-tagged
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