Sulfanyl chloride induced heterocyclization of N-(pyrazolyl)styrylacetamides

Article abstract of DOI:10.1080/10426507.2018.1528257

Heterocyclization of N-(pyrazol-3-yl)styrylacetamides with arenesulfenyl chlorides yields the corresponding tetrahydrofuran-2-iminium perchlorates isolable after chromatography as trans-5-aryl-4-(arylthio)tetrahydrofuran-2-ones and 5-aryl-4-(arylthio)-1-(

Full text of DOI:10.1080/10426507.2018.1528257

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: https://www.tandfonline.com/loi/gpss20
Sulfanyl chloride induced heterocyclization of N-
(pyrazolyl)styrylacetamides
Ivanna Yu. Danyliuk, Ruslan I. Vas’kevich, Alla I. Vas'kevich, Eduard B.
Rusanov & Mykhailo V. Vovk
To cite this article: Ivanna Yu. Danyliuk, Ruslan I. Vas’kevich, Alla I. Vas'kevich, Eduard
B. Rusanov & Mykhailo V. Vovk (2019): Sulfanyl chloride induced heterocyclization of N-
(pyrazolyl)styrylacetamides, Phosphorus, Sulfur, and Silicon and the Related Elements, DOI:
10.1080/10426507.2018.1528257
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PHOSPHORUS, SULFUR, AND SILICON
https://doi.org/10.1080/10426507.2018.1528257
Sulfanyl chloride induced heterocyclization of N-(pyrazolyl)styrylacetamides
a
a
b
a
a
Ivanna Yu. Danyliuk , Ruslan I. Vas’kevich , Alla I. Vas’kevich , Eduard B. Rusanov , and Mykhailo V. Vovk
a
b
Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine; National Technical University of Ukraine “Igor
Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
ABSTRACT
ARTICLE HISTORY
Heterocyclization of N-(pyrazol-3-yl)styrylacetamides with arenesulfenyl chlorides yields the corre-
sponding tetrahydrofuran-2-iminium perchlorates isolable after chromatography as trans-5-aryl-4-
Received 19 July 2018
Accepted 19 September 2018
(
arylthio)tetrahydrofuran-2-ones and 5-aryl-4-(arylthio)-1-(pyrazol-3-yl)pyrrolidin-2-ones, with the
latter predominating. N-(Pyrazol-4-yl)styrylacetamides react under analogous conditions to give
-aryl-4-(arylthio)-1-(pyrazol-4-yl)pyrrolidin-2-ones, 4-aryl-3-(arylthio)-4-chloro-N-(1-methylpyrazol-4-
KEYWORDS
Arenesulfenyl chlorides;
N-(pyrazolyl)styrylacetamides;
pyrrolidine-2-ones;
5
yl)butanamides, and tetrahydrofuran-2-iminium perchlorates which, when chromatographed,
produce 5-aryl-4-(arylthio)dihydrofuran-2(3H)-ones and 4-aryl-3-(arylthio)-4-methoxy-N-(1-methyl-
tetrahydrofuran-2-ones
1
H-pyrazol-4-yl)butanamides.
GRAPHICAL ABSTRACT
1
. Introduction
polyhydroarylthiobenzazepin-2-ones in addition to arylthio-
substituted pyrrolidin-2-ones and tetrahydrofuran-2-ones.
Conversions of this kind usually occur during the arenesul-
N-Substituted styrylacetamides are known to be biologically
significant compounds and valuable reagents for the prepar-
ation of functionalized heterocycles. They include inhibitors of
recombinant human monoamine oxidase
deacetylase, selective antagonists of A adenosine receptors
[
18]
fenylation of N-(thien-3-yl)styrylacetamides
hydrogenated (arylthio)thienoazepinones, thienylpyrrolones,
[3] and thienylfuranones.
to provide
[
1]
and histone
[
2]
[
4]
It was challenging to conduct such a cyclization with
other N-hetaryl-styrylacetamides in order to extend its syn-
thetic scope and to reveal some hitherto unknown features
of this reaction. Therefore, the present study concerns the
arylsulfenylation of N-(4-pyrazol-3-yl or -4-yl)styrylacetamides
and the neuropeptide YY 2 receptor as well as cardiovascu-
[
5]
[6]
larly and cytotoxically active compounds. The synthetic
potential of N-functionalized styrylacetamides was tested in some
electrophilic cyclization reactions, which revealed the effect of the
reagent structure on the regio- and chemoselectivity of these
reactions. As established, fluoro- and bromocyclizations of N-
hydroxy(acyloxy)-styrylacetamides mainly produce derivatives
1a-d and 5a-e synthesized for the first time with various sub-
stituents on the styryl moiety.
[
7,8]
[9]
of 4-halogenoiminolactones
or 4-bromolactones.
If
reacted with areneselenyl triflates, such styrylamides give 4-
2
. Results and discussion
We have established that N-(pyrazol-3-yl)styrylacetamides
a-c react with benzenesulfenyl chloride 2a in acetic acid in
[
10]
(
arylseleno)lactams
possibly mixed with 4-(arylseleno)lac-
[
11]
tones.
A similar Pd-catalyzed cyclization of N-tosyl-styryla-
[
12]
1
cetamide leads to 3-pyrrolin-2-one.
In our previous studies
N-aryl-styrylacetamides in highly polar media in the pres- form cyclic episulfonium perchlorates A and then to
[
13–15]
[16,17]
on the arenesulfenylation of the presence of LiClO
as a “doping” agent
to initially
4
[
16,17]
ence of LiClO as a “doping” agent,
a new alternative rearrange to tetrahydrofuran-2-iminium perchlorates
B
4
cyclization pathway was discovered which involved the which are isolable after chromatographic purification on silica
N-aryl group as
a
nucleophilic center and afforded gel as trans-5-aryl-4-(arylthio)tetrahydrofuran-2-ones 3a-c in
CONTACT Ivanna Yu. Danyliuk
ivannayu@ukr.net
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/icnv.
Supplemental data for this article can be accessed on the publisher’s website
ß 2019 Taylor & Francis Group, LLC

2
I. Y. DANYLIUK ET AL.
4
2-47% yields (see path a in Scheme 1). Nitromethane, a that the chemoselectivity of the 1a-d cyclization is mainly
more polar solvent which we successfully used in analogous governed by the structure of the arenesulfenyl chloride.
[
13–15,18]
reactions
does not promote the cyclization, probably
As cyclosulfenylation of styrylacetamides 1a-d gives rise to
due to the adduct formation between sulfenyl chloride and two new stereogenic centers at C-4 and C-5 of the tetrahydro-
the nucleophilic pyrazole nucleus. The adducts are not furan or pyrrolidone ring, it would be expected that both the
formed if nitromethane is replaced by acetic acid as a result products, 3 and 4, appear as four stereoisomers. In fact, this
1
13
of specific solvation of the latter.
does not happen and, according to the H and C NMR
The use of the softer analog 4-toluenesulfenyl chloride spectra of 3 and 4, a single diastereoisomer is formed for
b instead of benzenesulfenyl chloride 2a drastically either compound implying the high diastereoselectivity of the
2
changes the regiochemistry of the process. As we found, process. We propose a pathway for the cycloarenesulfenyla-
N-(pyrazol-3-yl)amides 1a-c react with 2 b to yield a mixture tion, which involves the following two successive steps:
of 5-aryl-4-arylthiotetrahydrofuran-2-ones 3d-f (20–27%)
and 5-aryl-4-arylthio-1-(pyrazol-3-yl)pyrrolidin-2-ones 4a-c a. An initial equally probable attack on both sides of the
(
60-76%), with ratios being practically independent of the
substrate double bond by the arenesulfenyl chloride
leading to two equally possible cyclic episulfonium
nature of the aryl substituent in the styryl moiety (see paths
a and b in Scheme 1 and Table 1). Pyrazol-1-yllactams 4a-c
synthesized by us have been reported to be of potential
[
23,24]
intermediates A
(one of them is shown in
Scheme 1).
[
19–22]
value in biomedical research.
b. A subsequent trans-attack on the intermediate A by the
At the same time, the reaction of the amides 1b,d with 4-
nitrobenzenesulfenyl chloride 2c affords the products 3g,h
in 52% and 65% yields, respectively, thus strongly suggesting
internal nucleophile, viz. the O or N atom.
Due to the trans-configuration of the initial substrates
1
a-d, the 4-arylthio and 5-aryl substituents are on the
opposite side of the tetrahydrofuran or pyrrolidone ring of
[
25–27]
the corresponding products.
The assumed geometry of
the 5-aryl-4-(arylthio)-1-(pyrazol-3-yl)pyrrolidin-2-ones syn-
thesized by us has been corroborated by X-ray diffraction
analysis of compound 4 b suggesting the relative (4RS,5SR)
configuration of the racemic pyrrolidin-2-ones (Figure 1).
In structure 4 b (Figure 1), the central 2-oxopyrrolidine
ring is non planar and has an envelope conformation with
dihedral angles between planes N1C1C2C4 and C2C3C4 of
ꢀ
2
6.0(2) . The pyrazole ring is planar with RMS deviation of
ꢀ
fitted atoms 0.0043 and forms a dihedral angle of 18.7(1)
with the N1C1C2C4 plane. Three nonequivalent formally
single bond lengths N1C1 1.367(3), N1C5 1.402(3) and
N1C4 1.471(3) Å where found. The last value corresponds
to standard C-N bond lengths (1.45-1.47 Å) whereas rest
ones corresponds to delocalized C-N bond lengths due to
conjugation of the lone pair on N1 with the p-system of the
Scheme 1. 1,4: Ar ¼ (a) Ph, (b) 4-Me-C
6
H
N-C
4
, (c), 4-F-C
6
H
4
; (d) 1: Ar ¼4-Cl-C
3: Ar ¼ Ph, (a) Ar ¼ Ph, (b) 4-Me-
, Ar ¼ (d) Ph, (e) 4-Me-C , (f) 4-F-C
, (h) 4-Cl-C
6 4
H
1
1
2
: Ar ¼ (a) Ph, (b) 4-Me-C
6
H
4
, (c), 4-O
; Ar ¼ 4-Me-C
, (g) 4-Me-C
2
H
6 4
1
C
6
H
4
, (c) 4-F-C
H
6 4
6
H
4
6
H
4
6 4
H ;
1
Ar ¼ 4-O
2
N-C
H
6 4
H
6 4
6 4
H .
Table 1. Preparative yields for the products of amides 1a-d cyclization.
Yields, %
1
Initial amide
Ar SCl
3a–h
4a–c
1
1
1
1
1
1
1
1
a
b
c
a
b
c
2a
2a
2a
2b
2b
2b
2c
2c
42
43
47
27
20
23
43
47
—
—
—
62
76
60
—
—
b
d
Figure 1. Molecular structure of 4b (50% ellipsoids probability).

PHOSPHORUS, SULFUR, AND SILICON
3
carbonyl group and the pyrazole ring. The bond lengths of
As seen from the experimental results obtained for the
S1C16 1.772(3) and S1C3 1.817(3) Å also differ because con- cyclosulfenylation of N-(pyrazol-4-yl)amides 5a–e, the prod-
jugation of the lone pairs on S1 with the p-system of the uct ratio for the competing lactonization and lactamization
aromatic ring C16-C21 is possible, whereas conjugation with processes is governed by the substituents on the aryl ring
3
the sp hybridized C3 atom is impossible.
both in the styryl moiety of the substrate and in the sulfeny-
N-(Pyrazol-4-yl)styrylacetamides 5a-c were reacted with lating reagent.
benzenesulfenyl chloride 2a in acetic acid in the presence of
The supposed structures of all synthesized compounds
1
13
an equimolar amount of LiClO , followed by chromato- are confirmed by their IR, H and C NMR spectra, and
4
1
graphic separation of the reaction mixture with a mixture of chromatography-MS coupling. As an example, the H NMR
chloroform/methanol (25:1) as eluents, to obtain furan-2- doublets (J ¼ 5.2-6.4 Hz) from the 5-H protons of the lac-
ones 3a-c and 4-aryl-4-methoxy-3-(phenylthio)-N-(1-methyl- tones 3a–k point to their trans-configuration with respect to
[
25]
1
1
1
H-pyrazol-4-yl)butanamides 6a–c with respective yields of the 4-H protons.
The H NMR spectra of the lactams 4a-
0–19% and 65–68% (see Scheme 2 and Table 2). It is most c exhibit the doublets of doublets from the methylene pro-
likely that the products are derived from the initially formed tons (2.51–2.54 and 3.06–3.08 ppm) and the multiplets from
iminium salts C under the conditions of chromatographic the methine protons (3.65–3.70 and 5.35–5.39 ppm) which
[
13–15,18]
separation. Thus, the butanamides 6a–c result from the are characteristic of such systems,
tetrahydrofuran ring cleavage with the eluent methanol.
resonances from the pyrazole ring. Similar spectra are
Likewise, amides 5a,b (Ar ¼ Ph, 4-Me-C H ) react with observed for the lactams 7a,b isomeric to 4a-c, with slightly
along with the
6
4
4
-toluenesulfenyl chloride 2 b to give pyrrolidin-2-ones 7a,b
Table 2. Yields of the cyclization products of the amides 5a–e.
and the corresponding iminium salts C which are converted
to the products 3d,e and 6d,e on chromatography. At the
same time, the analogous amides 5c–e bearing a halogen Initial amide
atom on the phenyl ring did not produce pyrrolidin-2-one 5a
derivatives in this reaction. Instead, only the products 3f,i,j
and 6f–h were isolated.
Yields, %
1
Ar SCl
3a–h
6a–h
7a,b
8a,b
2a
2a
2a
2b
2b
2b
2b
2b
2c
2c
19
11
10
15
22
20
10
24
22
20
65
68
67
41
43
69
75
64
—
—
—
—
—
30
30
—
—
—
—
—
—
—
—
—
—
—
—
—
71
69
5
5
5
b
c
a
In the reaction of the amides 5b,c (Ar ¼4-Me-C H , 4-F- 5b
6
4
5
5
5
c
d
e
C H ) with 4-nitrobenzenesulfenyl chloride 2c, electrophilic
6
4
addition predominates over cyclosulfenylation at the oxygen
atom. As a result, mainly N-(pyrazol-4-yl)butanamide deriva- 5b
tives 8a,b are yielded and lactones 3g,h appear as by-products.
5
c
1
1
Scheme 2. 5: Ar ¼ Ph (a), 4-Me-C
6
H
H
4
(b), 4-F-C
6
H
4
4
(c), 2-F-C
H
6 4
(d), 4-Cl-C
H
6 4
(e); 3: Ar ¼ 4-Me-C
6
H
4
, Ar ¼2-F-C
6
H
4
(i), 4-Cl-C
6
H
4
(j), Ar ¼ 4-O
2 6 4 6 4
N-C H , 4-F-C H (k);
1
1
6
: Ar ¼ Ph, Ar ¼ Ph (a), 4-Me-C
6
4
(b), 4-F-C
6
H
(c), Ar ¼ 4-Me-C , Ar ¼ Ph (d), 4-Me-C
6
H
4
6
H
4
(e), 4-F-C
6
H
4
(f), 2-F-C
H
6 4
(g), 4-Cl-C
6
H
4
(h); 7: Ar ¼ Ph (a), 4-Me-C
6 4
H
(
b); 8: Ar ¼4-Me-C (a), 4-F-C
6
H
4
H (b).
6 4

4
I. Y. DANYLIUK ET AL.
shifted methylene signals (2.51–2.57 and 3.06–3.12 ppm) and
methine signals (3.63–3.67 and 4.84–4.88 ppm).
In structure 6f shown in Figure 2, the pyrazole ring is
planar with RMS deviation of 0.0013 Å. The pyrazole ring
ꢀ
The linear adducts 8a,b give rise to the multiplet for 3-H mean plane makes a dihedral angle of 22.91(18) with the
(
4.23–4.28ppm) and the doublet for 4-H (5.89 ppm, C3-C18-O2-N3 moiety, whereas the N3-C19 and the N3-
1
J ¼ 6.8–7.2 Hz). H Resonances of the 3-arylthiobutanamides
C18 bond lengths are 1.409(3) and 1.344(4) Å, respectively.
Taken together, this suggests that the N3 lone electron pair
is conjugated with the p-systems of the carbonyl group and
the pyrazole ring. As another peculiarity, two phenyl rings,
6
a–h appear as multiplets for 3-H (3.65–3.74ppm) and 4-H
(4.34–4.38ppm), and by the singlet of the OCH3 group
(3.26–3.29ppm). Their structure is unambiguously established
by an X-ray diffraction analysis of 6f (Figure 2), which defin-
itely indicates the relative (3RS,4SR) configuration of the
racemic products. It is thus evident that the configuration at
C-5 is retained during the furan ring cleavage with methanol.
This special feature of nucleophilic substitution rules out a
methanol attack from the rear and is likely to result from two
ꢀ
C4-C9 and C12-C17, make a dihedral angle of 13.9(2) ,
accompanied by interatomic distances C4ꢁꢁꢁC17 and
C5ꢁꢁꢁC16 of 3.286 and 3.495Å, respectively. This geometry is
characteristic of the p-p intramolecular inter-phenyl inter-
action. The S1-C1 and the S1-C4 bond lengths are unequal
being 1.823(3) and 1.767(3) Å, respectively. The S1-C4 bond
shortening may well be attributed to the conjugation of the
S1 lone pairs with the p-system of the phenyl ring C4-C9.
Details for the crystal structure and data refinement
parameters are given in Table 3. Full crystallographic details
have been deposited at Cambridge Crystallographic Data
Centre (CCDC). Any request to the CCDC for these materi-
als should quote the full literature citation and reference
number CCDC 1849324 and CCDC 1836448.
[28–30]
successive S 2 reactions.
The first one, anchimerically
N
assisted by the sulfur atom in the arylthio moiety at the
b-position to the eliminating group, leads to the cyclic episul-
fonium intermediate D, which is subsequently attacked by
methanol as an external nucleophile.
3. Conclusions
We have demonstrated that cyclosulfenylation of N-pyra-
zolyl-styrylacetamides is a highly diastereoselective reaction.
The regiochemistry of the reaction is governed both by the
nature of the applied arenesulfenyl chlorides and the sub-
stituents in the styryl moiety of the substrates. As a result of
the study, novel arylthio derivatives of pyrrolidin-2-ones and
tetrahydrofuran-2-ones suitable for biological screening have
been synthesized and isolated in a pure state.
Figure 2. Molecular structure of 6f (30% ellipsoids probability).
Table 3. Crystal structure and data refinement parameters.
Compound
4b
6f
Empirical Formula
Formula Weight
C
22
H
23
N
3
OS
C
22
H
3 2
24FN O S
377.50
413.51
Crystal System/Space Group
Triclinic/P-1
9.605(11)
9.980(9)
10.961(8)
90.94(5)
110.26(2)
102.48(3)
957.6(15)
2
Monoclinic/C2/c
20.792(3)
5.1480(9)
39.597(9)
90
98.358(6)
90
4193.3(14)
8
a/Å
b/Å
c/Å
ꢀ
a/
ꢀ
b/
ꢀ
c/
3
V/Å
Z
D
3
calc (g/cm )
1.309
0.186
1.310
0.186
-
1
l (mm )
Crystal size (mm)
Color / Shape
F (000)
Theta range for collection
Reflections collected
Independent reflections
Data/restraints/parameters
0.07 ꢂ 0.27 ꢂ 0.37
Colorless
400
1.99–27.59
15430
4403
0.23 ꢂ 0.29 ꢂ 0.36
Colorless
1744
1.98–26.57
20211
4300
ꢀ
ꢀ
4403/0/247
1.027
4300/0/266
1.009
2
Goodness of fit on F
Final R1/wR2 [I > 2r(I)]
R1/wR2 [all data]
Largest difference peak/hole
0.0544/0.1100
0.1000/0.1290
0.40/ꢃ0.35
0.0561/0.1262
0.0984/0.1450
0.29/ꢃ0.21

PHOSPHORUS, SULFUR, AND SILICON
5
4
. Experimental
4.4. (4SR,5RS)-5-(4-Methylphenyl)-4-[(4-methylphenyl)thio]-
1
-(1-methyl-1H-pyrazol-3-yl)pyrrolidin-2-one (4b)
The IR spectra were recorded in KBr on a Bruker Vertex 70
1
13
ꢀ
spectrometer. The H and C NMR spectra were acquired White powder, m.p. 135–137 C (AcOEt), yield 0.57g (76%);
1
on a Varian VXR-400 instrument (400 and 126 MHz,
respectively) in pulsed Fourier transform mode in DMSO-d6
H NMR: 2.29 (3H, s, CH ); 2.36 (3H, s, CH ); 2.51 (1H, dd,
3 3
1
2
1
J ¼ 1.8, J ¼ 17.8, CH pyrrolidinone); 3.08 (1H, dd, J ¼ 7.8,
2
2
J ¼ 17.8, CH pyrrolidinone); 3.66–3.69 (4H, m, NCH , CHS
solution (compound 6f) or in CDCl solution (the rest of
2
3
3
pyrrolidinone); 5.36 (1H m, CH pyrrolidinone); 6.75 (1H,
the compounds), with TMS as internal standard. Coupling
constants J are given in Hz. Elemental analysis was per-
formed on a PerkinElmer 2400 CHN analyzer at the analyt-
ical laboratory of the Institute of Organic Chemistry,
National Academy of Sciences of Ukraine. Melting points
were determined on a Kofler bench and were not corrected.
The supplemental materials section contained the sample
d, J ¼ 2.0, CH pyrazol); 6.95 (2H, d, J ¼ 8.0, H Ar); 7.08
13
(
2H, d, J ¼ 8.4, H Ar); 7.15 (2H, d, J ¼ 8.0, H Ar); 7.17 (1H,
d, J ¼ 2.0, CHN pyrazol); 7.37 (2H, d, J ¼ 8.0, H Ar).
C
NMR: 21.11; 21.20; 36.90; 38.92; 48.53; 67.52; 97.59; 125.50;
1
1
29.45; 129.70; 130.04; 130.57; 133.27; 136.94; 137.38; 138.23;
ꢃ1
46.54; 171.43 (C ¼ O). IR/cm : 1677 (C¼O). Analysis for
1
13
C H N OS (377.50); Calculated, %: C 70.00; H 6.14; N
22 23 3
H NMR, C NMR spectra for 3a-3k, 7a,b and 8a,b.
1
1.13; S 8.49. Found, %: C 69.92; H 6.01; N 11.08; S 8.35.
4
.1. Synthesis of compounds 1, 5
4
.5. (4SR,5RS)-5-(4-Fluorophenyl)-4-[(4-methylphenyl)thio]-
1-(1-methyl-1H-pyrazol-3-yl)pyrrolidin-2-one (4c)
General method. To a stirred solution of the corresponding
styrylacetic acid (4 mmol) in CHCl (60 mL), SOCl (44 mL,
6
was heated at 60 C for 2 h, followed by cooling and low-
pressure evaporation of the solvent and the excess of SOCl2.
The solid residue was dissolved in CHCl3 (15 mL) and
3
2
ꢀ
White powder, m.p: 72–73 C (AcOEt), yield 0.46 g (60%);
mmol) in CHCl (30 mL)was added. The reaction mixture
1
1
2
3
ꢀ
H NMR: 2.36 (3H, s, CH ); 2.54 (1H, dd, J ¼ 2.4, J ¼ 18.0,
3
1
2
CH pyrrolidinon) ; 3.06 (1H, dd, J ¼ 7.8, J ¼ 17.8, CH
2
2
pyrrolidinon) ; 3.65–3.67 (4H, m, NCH , CHS pyrrolidinon);
3
5.36 (1H, m, CH pyrrolidinon) ; 6.75 (1H, d, J ¼ 2.0, CH
ꢀ
added dropwise at 0 C to a mixture of the corresponding
aminopyrazole (4.8 mmol) and triethylamine (0.67 mL,
pyrazol); 6.92–6.97 (2H, m, H Ar); 6.99–7.03 (2H, m, H Ar);
7
.15 (2H, d, J ¼ 8.4, H Ar); 7.18 (1H, d, J ¼ 2.0, CHN pyra-
13
5
.5 mmol) in CHCl (40 mL). After stirring the reaction mix-
3
zol); 7.37 (2H, d, J ¼ 7.6, H Ar). C NMR: 21.19; 36.89;
2
ture at room temperature for 8 h, the solvent was removed 38.90; 48.56; 67.21; 97.61; 115.65 (d, J ¼ 21.37); 127.31 (d,
CF
3
by low-pressure evaporation and water (20 mL) was added
to the residue. The resulting crystalline precipitate was fil-
tered off, washed with hexane (10 mL), and dried in air.
JCF ¼ 7.54); 129.45; 130.10; 130.65; 133.49; 135.75 (d,
4
1
JCF ¼ 3.77); 138.48; 146.35; 162.17 (d, J ¼ 246.4); 171.21.
CF
ꢃ1
IR/cm : 1702 (C¼O). Analysis for C21
H20FN OS (381.47);
3
Calculated, %: C 66.12; H 5.28; N 11.02, S 8.41. Found, %:
C 66.05; H 5.18; N 10.94, S 8.35.
4
.2. Compounds 3–8
To a stirred mixture of amide 1, 5 (2 mmol) and LiClO4
0.21 g, 2 mmol) in acetic acid (10 mL), a solution of 2 mmol
4
.6. (4SR,5RS)-4-Methoxy-N-(1-methyl-1H-pyrazol-4-yl)-4-
phenyl-3-(phenylthio)butanamide (6a)
(
arenesulfenyl chloride 2a-c in acetic acid (6 mL)was added
dropwise at room temperature. After stirring the reaction
mixture for 10 h, the solvent was removed under vacuum
and the residue was purified by column chromatography on
1
Yellow viscous oil, yield 0.50g (65%); H NMR: 2.58 (1H, dd,
1
2
1
2
J ¼ 8.6, J ¼ 15.4, CH ); 2.77 (1H, dd, J ¼ 4.4, J ¼ 15.2,
2
CH ); 3.28 (3H, s, OCH ); 3.78–3.83 (4H, m, CHSþ NCH );
2
3
3
4
.39 (1H, d, J ¼ 5.2, CH); 7.18–7.25 (11H, m, 10H Arþ H-5
13
silica gel with CHCl /MeOH (25:1) as eluent.
3
pyrazol); 7.74 (1H, s, NH); 7.83 (1H, s, H-3 pyrazol).
C
NMR: 37.13; 38.63; 51.99; 57.18; 84.81; 120.39; 122.07; 126.72;
4
.3. (4SR,5RS)-4-[(4-Methylphenyl)thio]-1-(1-methyl-1H-
1
1
26.79; 127.60; 127.91; 128.46; 129.42; 131.76; 134.16; 138.07;
pyrazol-3-yl)-5-phenylpyrrolidin-2-one (4a)
ꢃ1
67.60 (C ¼ O). IR/cm : 3256 (N-H); 1613 (C¼O). Analysis
1
for C H N O S (381.49); Calculated, %: C 66.12; H 6.08; N
Yellow viscous oil, yield 0.45 g (62%); H NMR: 2.36 (3H, s,
21 23 3 2
1
2
11.01; S 8.41. Found, %: C 66.07; H 6.03; N 10.97; S 8.38.
CH ); 2.52 (1H, dd, J ¼ 1.8, J ¼ 17.8, CH pyrrolidinone);
3
2
1
2
3
.08 (1H, dd, J ¼ 8.0, J ¼ 18.0, CH pyrrolidinone); 3.66
2
4
.7. (4SR,5RS)-4-Methoxy-4-(4-methylphenyl)-N-(1-methyl-
(3H, s, NCH ); 3.68–3.70 (1H, m, CHS pyrrolidinone); 5.39
3
1
H-pyrazol-4-yl)-3-(phenylthio)butanamide (6b)
(
1H, m, CH pyrrolidinone); 6.77 (1H, d, J ¼ 2.0, CH pyra-
zol); 7.05 (2H, d, J ¼ 7.2, H Ar); 7.15 (2H, d, J ¼ 7.6, H Ar);
1
Yellow viscous oil, yield 0.54 g (68%); H NMR: 2.30 (3H, s,
1
2
7
.18 (1H, d, J ¼ 2.4, CHN pyrazol); 7.21–7.29 (3H, m, H
13
CH ); 2.57 (1H, dd, J ¼ 8.2, J ¼ 15.4, CH ); 2.77 (1H, dd,
3
2
1
2
Ar); 7.38 (2H, d, J ¼ 8.0, H Ar). C NMR: 21.19; 36.90;
J ¼ 4.8, J ¼ 15.2, CH ); 3.28 (3H, s, OCH ); 3.76–3.81 (1H,
2
3
3
1
8.89; 48.55; 67.69; 97.55; 125.58; 127.62; 128.75; 129.63;
m, CHS); 3.84 (3 H, s, NCH ); 4.37 (1H, d, J ¼ 5.2, CH);
3
30.06; 130.57; 133.40; 138.33; 139.96; 146.54; 171.40 7.09–7.14 (5H, m, H Ar); 7.20–7.22 (2H, m, H Ar); 7.32
ꢃ1
(
(
C¼O). IR/cm : 1701 (C¼O). Analysis for C H N OS (1 H, s, H-5 pyrazol); 7.34–7.36 (2H, m, H Ar); 7.62 (1H, s,
2
1
21 3
13
363.48); Calculated, %: C 69.39; H 5.82; N 11.56; S 8.82. NH); 7.84 (1H, s, H-3 pyrazol). C NMR: 21.10; 37.69;
39.11; 52.40; 57.52; 85.10; 120.84; 122.44; 127.08; 127.18;
Found, %: C 69.28; H 5.72; N 11.49; S 8.76.

6
I. Y. DANYLIUK ET AL.
1
1
28.88; 129.07; 129.82; 132.17; 134.63; 135.43; 137.79; 4.11. (3RS,4SR)-4-(4-Fluorophenyl)-4-methoxy-3-[(4-
ꢃ1
68.00. IR/cm : 3255 (N-H); 1618 (C¼O). Analysis for
methylphenyl)thio]-N-(1-methyl-1H-pyrazol-4-
yl)butanamide (6f)
C H N O S (395.52); Calculated, %: C 66.81; H 6.37; N
2
2
25
3
2
1
0.62; S 8.11. Found, %: C 66.77; H 6.30; N 10.58; S 8.05.
ꢀ
1
White powder, m.p: 119–122 C, yield 0.57 g (69%);
H
1
NMR: 2.30 (3H, s, CH3 ArS); 2.56 (1H, dd, J ¼ 8.6,
2
1
2
J ¼ 14.8, CH ); 2.75 (1H, dd, J ¼ 4.6, J ¼ 14.6, CH ); 3.26
2
2
4
.8. (4SR,5RS)-4-(4-Fluorophenylphenyl)-4-methoxy-N-(1-
(
3H, s, OCH ); 3.65–3.70 (1H, m, CHS); 3.86 (3H, s,
3
methyl-1H-pyrazol-4-yl)-3-(phenylthio)butanamide (6c)
NCH ); 4.34 (1H, d, J ¼ 5.2, CHOCH ); 6.98 (2 H, t, J ¼ 8.4,
3
3
1
Yellow viscous oil, yield 0.54 g (67%); H NMR: 2.58 (1H,
H Ar); 7.03 (2 H, d, J ¼ 7.6, H Ar); 7.20–7.24 (4 H, m, H
1
2
1
2
dd, J ¼ 8.0, J ¼ 15.2, CH ); 2.81 (1H, dd, J ¼ 4.8, J ¼ 15.2,
2
Ar); 7.33 (1H, s, H-5 pyrazol). 7.45 (1H, s, NH); 7.86 (1H, s,
13
CH ); 3.25 (3H, s, OCH ); 3.74–3.78 (1H, m, CHS); 3.86
2
3
H-3 pyrazol). C NMR: 21.09; 37.79; 39.20; 52.93; 57.52;
2
(
3 H, s, NCH ); 4.34 (1H, d, J ¼ 6.0, CH); 6.96 (2H, t,
3
84.70; 115.23 (d, JCF ¼ 22.63); 120.88; 122.39; 128.96 (d,
1
3
J ¼ 8.0, H Ar); 7.19–7.30 (7H, m, H Ar); 7.34 (1 H, s, H-5
JCF ¼ 7.54); 129.75; 129.97; 130.66; 132.87; 134.52 (d,
1
3
4
1
pyrazol); 7.60 (1H, s, NH); 7.86 (1H, s, H-3 pyrazol).
C
JCF ¼ 3.77); 137.65; 162.48 (d, J ¼ 246.4); 167.91 (C ¼ O).
CF
ꢃ1
NMR: 37.95; 39.18; 52.57; 57.49; 84.83; 115.22 (d,
IR/cm
:
3312 (N-H); 1653 (C¼O). Analysis for
2
3
JCF ¼ 21.37); 120.81; 122.50; 127.31; 127.48 (d, J ¼ 7.54);
CF
C H FN O S (413.51); Calculated, %: C C 63.90; H 5.85;
22 24 3 2
4
1
28.92; 129.00; 132.19; 134.38 (d, J ¼ 2.51); 134.52; 162.48
CF
N 10.16; S 7.75. Found, %: C 63.82; H 5.76; N 10.03; S 7.66.
1
ꢃ1
(
1
d, JCF ¼ 246.4); 167.83 (C ¼ O). IR/cm : 3261 (N-H);
624 (C¼O). Analysis for C H FN O S (399.48);
21
22
3 2
Calculated, %: C 63.14; H 5.55; N 10.52; S 8.03. Found, %:
C 63.09; H 5.50; N 10.48; S 7.97.
4
.12. (4SR,5RS)-4-(2-Fluorophenyl)-4-methoxy-3-[(4-
methylphenyl)thio]-N-(1-methyl-1H-pyrazol-4-
yl)butanamide (6g)
ꢀ
1
White powder, m.p: 118–121 C, yield 0.62 g (75%);
H
4.9. (4SR,5RS)-4-Methoxy-3-[(4-methylphenyl)thio]-N-(1-
1
NMR: 2.29 (3H, s, CH3 ArS); 2.54 (1H, dd, J ¼ 9.2,
methyl-1H-pyrazol-4-yl)-4-phenylbutanamide (6d)
2
1
2
J ¼ 15.2, CH ); 2.75 (1H, dd, J ¼ 4.6, J ¼ 15.4, CH ); 3.29
2
2
ꢀ
1
White powder, m.p: 130–132 C, yield 0.32 g (41%);
H
(3H, s, OCH ); 3.83–3.85 (4H, m, CHS, NCH ); 4.74 (1H, d,
3 3
1
NMR: 2.30 (3H, s, CH3 ArS); 2.56 (1H, dd, J ¼ 8.2, J ¼ 5.2, CHOCH ); 6.97–7.10 (4 H, m, H Ar); 7.21–7.36
3
2
1
2
J ¼ 15.8, CH ); 2.75 (1H, dd, J ¼ 5.6, J ¼ 15.6, CH ); 3.29 (5 H, m, 4 H Ar þ H-5 pyrazol); 7.75 (1H, s, NH); 7.82 (1H,
2
2
13
(
3H, s, OCH ); 3.70–3.75 (1H, m, CHS); 3.84 c (3H, s, s, H-3 pyrazol). C NMR: 21.11; 37.51; 39.18; 51.17; 57.88;
3
2
NCH ); 4.39 (1H, d, J ¼ 5.2, CHOCH ); 7.04 (2 H, d, J 7.2, 79.06; 115.53 (d, JCF ¼ 21.37); 120.89; 122.44; 124.12 (d,
3
3
4
2
3
H Ar); 7.23–7.32 (8 H, m, 7H Ar þ H-5 pyrazol); 7.71 (1H,
JCF ¼ 3.77); 125.92 (d, J ¼ 12.57); 128.09 (d, J ¼ 5.03);
CF
CF
13
3
s, NH); 7.84 (1H, s, H-3 pyrazol). C NMR: 21.12; 37.28; 129.57 (d,
J
¼ 8.79); 129.72; 129.95; 130.42; 132.82;
1 ꢃ1
CF
3
1
1
9.19; 52.87; 57.69; 120.89; 122.40; 127.20; 128.05; 128.40; 137.59; 160.89 (d, J ¼ 245.14); 167.88 (C ¼ O). IR/cm
:
CF
29.76; 129.93; 130.01; 130.77; 132.93; 137.59; 138.70; 3315 (N-H); 1645 (C¼O). Analysis for C H FN O S
2
2
24
3 2
ꢃ1
67.97. IR/cm : 3254 (N-H); 1610 (C¼O). Analysis for (413.51); Calculated, %: 63.90; H 5.85; N 10.16; S 7.75.
C H N O S (395.52); Calculated, %: C 66.81; H 6.37; N Found, %: C 63.83; H 5.77; N 10.02; S 7.64.
2
2
25
3
2
1
0.62; S 8.11. Found, %: C 66.73; H 6.25; N 10.54; S 8.04.
4
.10. (4SR,5RS)-4-Methoxy-4-(4-methylphenyl)-3-[(4-
methylphenyl)thio]-N-(1-methyl-1H-pyrazol-4-
yl)butanamide (6e)
4.13. (4SR,5RS)-4-(4-Chlorophenyl)-4-methoxy-3-[(4-
methylphenyl)thio]-N-(1-methyl-1H-pyrazol-4-
yl)butanamide (6h)
1
ꢀ
1
Yellow viscous oil, yield 0.35 g (43%); H NMR: 2.30 (3H, s, White powder, m.p: 116–118 C, yield 0.55 g (64%);
H
1
1
CH ArS); 2.32 (3H, s, CH3 Ar); 2.55 (1H, dd, J ¼ 7.6, NMR: 2.30 (3H, s, CH3 ArS); 2.54 (1H, dd, J ¼ 8.6,
3
2
1
2
2
1
2
J ¼ 15.4, CH ); 2.74 (1H, dd, J ¼ 4.8, J ¼ 15.2, CH ); 3.29 J ¼ 15.0, CH ); 2.76 (1H, dd, J ¼ 4.8, J ¼ 15.2, CH ); 3.26
2
2
2
2
(
3H, s, OCH ); 3.68–3.73 (1H, m, CHS); 3.85 c (3H, s, (3H, s, OCH ); 3.66–3.71 (1H, m, CHS); 3.85 (3H, s,
3
3
NCH ); 4.36 (1H, d, J ¼ 5.2, CHOCH ); 7.04 (2 H, d, J ¼ 8.0, NCH ); 4.32 (1H, d, J ¼ 5.2, CHOCH ); 7.03 (2 H, d, J 8.0,
3
3
3
3
H Ar); 7.12–7.13 (3 H, m, H Ar); 7.25–7.27 (3 H, m, H Ar); H Ar); 7.16–7.21 (4 H, m, H Ar); 7.24 (2 H, s, H Ar); 7.32
.31 (1H, s, H-5 pyrazol); 7.60 (1H, s, NH); 7.84 (1H, s, H-3 (1 H, s, H-5 pyrazol); 7.54 (1H, s, NH); 7.84 (1H, s, H-3
7
1
3
13
pyrazol). C NMR: 21.10; 21.14; 37.54; 39.10; 52.79; 57.54; pyrazol). C NMR: 21.10; 37.70; 39.18; 52.77; 57.61; 84.69;
8
1
3
5.01; 120.99; 122.47; 127.12; 129.09; 129.72; 129.93; 130.78; 120.81; 122.45; 128.50; 128.69; 129.76; 129.91; 130.57;
ꢃ1
ꢃ1
32.89; 135.57; 137.51; 137.74; 168.23 (C ¼ O). IR/cm
:
132.87; 133.81; 137.31; 137.70; 167.83 (C ¼ O). IR/cm
:
244 (N-H); 1615 (C¼O). Analysis for C H N O S 3322 (N-H); 1654 (C¼O). Analysis for C H ClN O S
23
27
3
2
22 24
3
2
(409.54); Calculated, %: C 67.45; H 6.65; N 10.26; S 7.83. (429.96); Calculated, %: C 61.46; H 5.63; N 9.77; S 7.46.
Found, %: C 67.35; H 6.56; N 10.19; S 7.74. Found, %: C 61.37; H 5.54; N 9.69; S 7.38.

PHOSPHORUS, SULFUR, AND SILICON
7
4.14. X-ray structure determination
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2
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4
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