Nucleophilic sulfanylation of 1,5-disubstituted pent-2-en-4-yn-1-ones

Article abstract of DOI:10.1134/S1070428014010035

Regioselectivity of nucleophilic addition of benzenethiols and phenylmethanethiol to 1,5-diarylpent-2-en-4-yn-1-ones in ethanol in the presence of triethylamine at 0-30 C is determined by the nucleophile nature. Phenylmethanethiol adds to the double bond,

Full text of DOI:10.1134/S1070428014010035

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 1, pp. 13–20. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © A.A. Golovanov, D.M. Gusev, A.V. Vologzhanina, V.V. Bekin, V.S. Pisareva, 2014, published in Zhurnal Organicheskoi Khimii,
2014, Vol. 50, No. 1, pp. 21–28.
Nucleophilic Sulfanylation
of 1,5-Disubstituted Pent-2-en-4-yn-1-ones
A. A. Golovanova, D. M. Guseva, A. V. Vologzhaninab, V. V. Bekina, and V. S. Pisarevaa
a Togliatti State University, ul. Belorusskaya 14, Togliatti, 445667 Russia
e-mail: aleksandgolovanov@yandex.ru
b Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
ul. Vavilova 28, Moscow, 119991 Russia
Received April 20, 2013
Abstract—Regioselectivity of nucleophilic addition of benzenethiols and phenylmethanethiol to 1,5-diaryl-
pent-2-en-4-yn-1-ones in ethanol in the presence of triethylamine at 0–30°C is determined by the nucleophile
nature. Phenylmethanethiol adds to the double bond, whereas benzenethiols add to the triple bond. The addition
products, 1,5-diaryl-3-benzylsulfanylpent-4-yn-1-ones and 1,5-diaryl-5-(4-arylsulfanyl)penta-2,4-dien-1-ones,
respectively, were isolated in 43–89% yield. Substituents in the aryl rings of the substrates did not affect the
reaction direction.
DOI: 10.1134/S1070428014010035
Nucleophilic sulfanylation of activated α,β-unsatu-
rated compounds provides a simple and efficient
synthetic route to sulfides [1–4] and sulfur-containing
heterocyclic compounds [5–7]. This reaction smoothly
occurs in polar solvents in the presence of bases, such
as amines, alkoxides, and alkalies. Thiols add espe-
cially readily to α,β-unsaturated [8] and acetylenic
ketones [5, 9]. In all cases, nucleophilic attack by the
reagent is directed at the β-carbon atom of the multiple
bond (1,4-addition), and the yields of addition products
attain 80–90%. Acetylenic ketones are more reactive
than their vinyl analogs [10] in nucleophilic sul-
fanylation.
Addition of thiols to activated vinylacetylenes was
studied to a considerably lesser extent. It is known that
nucleophilic sulfanylation of enynoic acids and enyne
ketones may involve both double and triple bonds
therein, depending on the substrate structure, reagent
and catalyst nature, and reaction conditions. Ketones
with the general formula R′CH=CHC(O)C≡CR″ in the
presence of bases at room temperature in alcohol take
up benzenethiols and ethanethiol primarily at the triple
bond [10, 14], whereas mixtures of several further
sulfanylation products are formed when excess reagent
is used [10]. Sodium hydrogen sulfide reacts at both
multiple bonds of such ketones, yielding 2,3-dihydro-
pyran-4-ones [7].
Sulfanylation of acetylenic ketones is characterized
by some stereochemical peculiarities. Thermodynam-
ically controlled reaction of 1,3-diarylprop-2-yn-1-
ones with benzenethiols in the presence of trialkyl-
amines, regardless of the reactant nature, leads to the
formation of a mixture of E- and Z-isomeric 1-aryl-3-
arylsulfanylprop-2-en-1-ones [11], the Z isomer ap-
preciably prevailing. The E/Z-isomer ratio under
kinetic control is determined mainly by the active
reagent species (whether it acts as amine–thiol H-com-
plex, ion pair, or free Et3NH+ and ArS– ions), as well as
by the solvent nature and substituent in arenethiol.
Analogous conclusions were drawn while studying the
reaction kinetics [12, 13].
Benzenethiol and ethanethiol add only to the double
bond of enynes XCH=CHC≡CR (X = CO2Me, CN,
COMe) in the presence of sodium ethoxide to afford
acetylenic sulfides which undergo rearrangement into
dienic ketones on prolonged storage (24–72 h) in the
presence of EtONa [15]. The transformation of acety-
lenic sulfanylation products into dienes is interpreted
as reversible addition–elimination of thiol to the double
bond and irreversible addition to the triple bond.
Taking into account that some unsaturated sulfides
exhibit anticarcinogenic activity and may also be used
as antibiotics and coenzymes [16], development of
convenient procedures for their synthesis from ac-
13

GOLOVANOV et al.
14
tivated vinylacetylenic compounds is an important
problem. In the present work we studied regio- and
stereoselectivity of sulfanylation of 1,5-diarylpent-2-
en-4-yn-1-ones Ia–Ig and the structure of the sul-
fanylation products.
Acetylenic keto sulfides IIIa–IIIf were isolated as
colorless crystalline substances. Their structure was
confirmed by spectral data, as well as by X-ray anal-
1
ysis. The H NMR spectra of III contained two dou-
blets of doublets at δ 3.43–3.62 (J = 16.8–17.4, 7.8–
8.0 Hz) and 3.25–3.48 ppm (J = 16.9, 6.2–6.3 Hz) due
to diastereotopic protons 2-HA and 2-HB (Fig. 1). The
3-H proton appeared as a doublet of doublets at
δ 4.18–4.35 ppm (J = 7.6–7.7, 6.3–6.4 Hz), and the
benzylic protons (18-HA and 18-HB) gave two doublets
at δ 4.03–4.08 (J = 13.3–13.7 Hz) and 3.99–4.02 ppm
(J = 13.3 Hz). In the 13C NMR spectra of IIIa–IIIf,
signals from the triple-bonded carbon atoms were
located at δC 87.8–89.5 (C4) and 84.1–88.6 ppm (C5),
the carbonyl carbon signal was observed at δC 185.0–
195.9 ppm (C1), and signals at δC 43.9–44.2, 30.5–
30.6, and 35.3–36.1 ppm were assigned to alkyl carbon
atoms (C2, C3, and C18, respectively).
Ar1
Ar2
O
Ia–Ig
Ar1 = Ph (a, g), 4-MeC6H4 (b), 4-MeOC6H4 (c), 4-ClC6H4 (d),
4-BrC6H4 (e), furan-2-yl (f); Ar2 = Ph (a–f), 4-BrC6H4 (g).
Compounds Ia–Ig were selected as substrates due
to the possibility for easy variation of electron density
in the enyne fragment via introduction of electron-
donating or electron-withdrawing substituents into the
Ar1 and Ar2 aryl rings [17]. According to the IR,
1H NMR, and X-ray diffraction data, vinylacetylenic
ketones described by us previously [18] have E con-
figuration in the crystalline state and in solution.
As sulfanylating agents we used phenylmethane-
thiol (IIa), and benzenethiols IIb–IId (Ar3 = Ph,
4-MeC6H4, 4-BrC6H4). Preliminarily, we found that no
sulfanylation of ketones I occurred in the absence of
a catalyst. Addition of a catalytic amount of triethyl-
amine ensured smooth sulfanylation in ethanol even at
room temperature. Thiol IIa adds to the double bond
of Ia, leading to the formation of 1,5-diaryl-3-benzyl-
sulfanylpent-4-yn-1-ones III with high regioselectivity
in the temperature range from 0 to 30°C (Scheme 1).
The highest yields (89–90%) were obtained in the
sulfanylation of ketones Id and Ie containing a halogen
atom in the para position of the Ar1 ring. Substituents
in Ar1 and Ar2 in the initial ketones did not affect the
direction of the addition of thiol IIa.
The IR spectra of IIIa–IIIf lacked absorption bands
assignable to stretching vibrations of diene (1650,
1600 cm–1) or allene bond system (1950–1930 cm–1).
The carbonyl group gives rise to a strong narrow peak
at 1690–1676 cm–1, which suggests its conjugation
only with aryl ring. The C≡C stretching vibration band
(~2230 cm–1) is characterized by a low intensity and is
observed only at a high sample concentration, presum-
ably due to high pseudosymmetry. The structure of
IIIa–IIIe was proved by X-ray analysis.
Ketones I reacted with benzenethiols IIb–IId under
analogous conditions, but thiols II added to the triple
bond of I, affording dienic keto sulfides IV (Scheme 1).
The best yields (82–83%) were obtained in the sul-
fanylation of ketone Id. Donor substituents in the aryl
rings of ketones I (Ar1, Ar2) and benzenethiols II (Ar3)
reduced the yield to 43–66%.
Scheme 1.
Ar2
Ar1
PhCH2SH, Et3N
O
S
Ph
IIIa–IIIf
I
H1
H3
H1
H3
Ar3SH, Et3N
Ar1
Ar2
Ar3
Ar1
S
+
Ar3
O
H2
S
O
H2
E,E
Ar2
E,Z
IVa–IVf
III, Ar1 = Ph (a, f), 4-MeC6H4 (b), 4-ClC6H4 (c), 4-BrC6H4 (d), furan-2-yl (e); Ar2 = Ph (a–e), 4-BrC6H4 (f); IV, Ar1 = Ar2 = Ph,
Ar3 = 4-BrC6H4 (a); Ar1 = 4-MeC6H4, Ar2 = Ph, Ar3 = 4-BrC6H4 (b); Ar1 = 4-MeOC6H4, Ar2 = Ph, Ar3 = 4-BrC6H4 (c); Ar1 =
4-ClC6H4, Ar2 = Ar3 = Ph (d); Ar1 = 4-ClC6H4, Ar2 = Ph, Ar3 = 4-MeC6H4 (e); Ar1 = 4-ClC6H4, Ar2 = Ph, Ar3 = 4-BrC6H4 (f).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

NUCLEOPHILIC SULFANYLATION OF 1,5-DISUBSTITUTED PENT-2-EN-4-YN-1-ONES
15
Ketones IVa–IVf were isolated as bright yellow
C9
C8
crystalline substances which are stable on storage.
1
C10
C11
According to the H NMR data, adducts IV are mix-
tures of E,E and E,Z isomers. The major E,Z isomer is
represented in the H NMR spectra by two doublets at
1
δ 6.97–7.05 (J = 11.2–11.5 Hz) and 7.05–7.10 ppm
(J = 11.2–11.5 Hz) from 3-H and 1-H and by a doublet
of doublets at δ 8.20–8.29 ppm (J = 11.2–11.5, 14.9–
14.4 Hz) from 2-H. The latter signal is displaced
appreciably downfield relative to the 3-H and 1-H
signals, which may be due to deshielding effect of the
C7
C6
C5
C4
C3
C23
C22
O1
C24
C14
C13 C1
H18B
C19
C2
C15
1
Ar3 ring. In the H NMR spectra of the E,E isomers,
C18
C12
C17
C21
H2A
the doublets at δ 6.19–6.29 (J = 11.7 Hz) and 6.74–
6.88 ppm (J = 14.7–14.9 Hz) with the coupling con-
stants typical of trans configuration correspond to 1-H
and 3-H, respectively. The 2-H signal is overlapped by
those belonging to aromatic protons. The E,E/E,Z ratio
in CDCl3 ranges from 1:1.5 to 1:2.7; compounds IVc
and IVe in solution were pure E,Z isomers. In the 13C
NMR spectra of IVa, IVb, and IVd–IVf we observed
two signals in the region δC 180–190 ppm, which
belong to the carbonyl carbon atoms of the two
isomers.
H2B
C20
H18A
S1
C16
Fig. 1. Structure of the molecule of 1,5-diphenyl-3-benzyl-
sulfanylpent-4-yn-1-one (IIIa) according to the X-ray dif-
fraction data. Non-hydrogen atoms are shown as thermal
vibration ellipsoids with a probability of 50%.
under catalysis by tertiary amines the nucleophilic
species is benzenethiolate ion, both free and in a sol-
vent-separated ion pair (RC6H4S– ||HN+Et3) [20, 21].
Quantum chemical calculations [17] showed that elec-
trophilic centers in ketones I may be the C1, C3, and C5
atoms; however, the double bond is more polarizable
and is more sensitive than the triple bond to the
activating effect of the carbonyl group. Therefore, the
double bond is more reactive toward such soft bases as
thiols. Presumably, all thiols IIa–IId initially add to
the double bond of I (kinetically controlled process).
Due to fairly high resonance stability of benzene-
thiolate ions, the reaction with benzenethiols IIb–IId
is reversible [22]. Benzenethiolate ion occurring in
equilibrium with acetylenic keto sulfide V slowly adds
to the triple bond of I, yielding adduct IV (thermo-
dynamically controlled process; Scheme 2).
The IR spectra of compounds IV in CCl4 contained
two poorly resolved carbonyl stretching vibration
bands. The high-frequency band (1657–1660 cm–1)
corresponds to the E,Z isomer, and the shoulder at
1645–1637 cm–1, to the E,E isomer. The assignment of
these bands to C=O stretching vibrations is confirmed
by their low-frequency shift by 5–6 cm–1 in going from
carbon tetrachloride to more polar methylene chloride
[19]. The IR spectra of crystalline samples (in KBr)
displayed only one carbonyl band (1653–1648 cm–1),
indicating that compounds IV in crystal are likely to
exist as a single isomer.
Thus, as with 1,3-diarylprop-2-yn-1-ones, the ad-
dition of benzenethiols to ketones I in the presence of
triethylamine gives mixtures of two stereoisomers, the
Z isomer prevailing.
Unlike benzenethiolate ion, resonance stabilization
of PhCH2S– is impossible. Therefore, the addition of
phenylmethanethiol to vinylacetylenic ketones I is
almost irreversible, and no subsequent transformation
of acetylenic keto sulfides III into dienes is observed.
It is known that in the sulfanylation of α,β-unsat-
urated ketones in polar solvents (alcohols, acetonitrile)
Scheme 2.
Ar2
Ar1
(Ar3S– ||HNEt3)
(PhCH2S– ||HNEt3)
III
I
–(Ar3S– ||HNEt3)
(Ar3S– ||HNEt3)
O
S
Ar3
V
IV
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

GOLOVANOV et al.
16
Table 1. Some bond lengths (Å) in molecules IIIa–IIIe
Bond
IIIa IIIb IIIc IIId IIIe
C1–O1 1.218(4) 1.217(2) 1.219(1) 1.216(2) 1.216(4)
C1–C2 1.517(4) 1.519(2) 1.516(2) 1.516(2) 1.512(4)
C2–C3 1.522(4) 1.533(3) 1.526(2) 1.530(2) 1.538(4)
C3–C4 1.467(4) 1.461(2) 1.465(2) 1.463(2) 1.464(4)
C4–C5 1.199(4) 1.198(2) 1.195(2) 1.196(2) 1.201(4)
C3–S1 1.829(3) 1.836(1) 1.834(1) 1.835(2) 1.824(3)
S1–C18 1.821(3) 1.821(2) 1.821(1) 1.823(2) 1.815(4)
our present data on the steric structure of compounds
IV, we can state that the addition reactions of benzene-
thiols to vinylacetylenic ketones I and 1,3-diarylprop-
2-yn-1-ones are analogous from the stereochemical
viewpoint.
Substituents in the aryl rings of vinylacetylenic
ketones I do not affect the direction of nucleophilic
attack by thiol but only the yield of adducts. Therefore,
the selectivity of the addition is determined mainly by
the chemical nature of the reagent. The proposed
scheme makes it possible to rationalize the regioselec-
tivity of reactions with different thiols. Undoubtedly,
further more detailed studies of nucleophilic reactions
with activated enyne systems are necessary to confirm
the proposed mechanism.
Table 2. Some bond and torsion angles (deg) in molecules
IIIa–IIIe
Angle
IIIa
IIIb
IIIc
IIId
IIIe
O1C1C2
C1C2C3
C4C3C2
C3C4C5
C18S1C3
121.7(3) 121.4(2) 121.6(1) 121.7(1) 122.2(3)
113.2(3) 113.7(1) 114.0(1) 113.1(1) 111.8(3)
111.6(3) 112.1(1) 112.1(1) 111.7(1) 111.5(3)
176.2(3) 178.1(1) 177.7(1) 177.5(1) 176.1(3)
100.6(2) 100.5(1) 100.8(1) 100.5(1) 100.6(2)
The X-ray diffraction data for compounds III
showed that rupture of conjugation leads to extension
of not only C2–C3 bond (Fig. 1; Tables 1, 2) where
thiol adds but also of the neighboring C3–C4 and (to
a lesser extent) C1–C2 bonds and that the triple C4–C5
bond slightly shortens [18]. The fact that in all cases
the S1–C18 bond is shorter than S1–C3 indicates elec-
tron density transfer from the phenyl group of the
benzyl fragment. This also follows from the formation
of characteristic intermolecular contacts (see below).
Unlike initial ketones I [18], the Ar1 ring lies almost in
the plane passing through the C12, C1, O1, and C2
atoms. Insofar as rotation of the Ar1 ring about the
ordinary C1–C12 bond should not be hindered, its
coplanar arrangement is likely to be determined by
intermolecular contacts. In fact, molecules IIIa–IIId in
crystal are linked to form dimers via C2–H2B···π(Ar1)
interactions; the dimers formed by compounds IIIb,
IIId, and IIIe are additionally stabilized by
C3–H···H(Me) or C3–H···Hlg interactions. Here, the
distance between the coplanar ArCOCH2 fragments
(through inversion center) is 3.19(1)–3.53(1) Å. The
presence in molecule IIIe of an electron-acceptor furan
oxygen atom makes H···O(Ar1) interactions more
favorable than H···π(Ar1). The identity of the substit-
uents on C5 and C1 in compounds IIIa–IIId enables
analogous contacts (C=O···H) with participation of
hydrogen atoms in the meta positions of different
phenyl groups (Ar2 and benzylic phenyl group), since
displacement of the electron density toward the triple
bond and sulfur atom should result in localization of
partial positive charge just on the above atoms.
Analogous contact with hydrogen atom of the benzylic
fragment was also detected for compound IIIe and
initial ketones I (Ar2 = Ph). If Ar2 ≠ Ph, electron
density redistribution and steric hindrances hamper this
O1C1C12C13 1.3
1.9
0.2
3.6
2.2a
O1C1C12O2.
a
In order to confirm the proposed mechanism, we tried
to detect kinetically controlled adduct V in the reaction
mixtures. In the IR spectrum of the reaction mixtures,
recorded in 15 min after addition of triethylamine,
we observed two absorption bands in the carbonyl
stretching vibration region, at 1687–1676 and 1655–
1649 cm–1. In some cases, the high-frequency band
appeared as a shoulder. The absorption band at
~1685 cm–1 corresponds to the adduct in which the
carbonyl group is conjugated only with the aryl ring,
i.e., to the kinetically controlled product (V). The low-
frequency band arises from the C=O group of dienic
keto sulfides IV. After 18 h, the high-frequency band
disappears almost completely from the IR spectrum,
whereas the intensity of the low-frequency band
appreciably increases. Kinetically controlled adduct V
was also detected in the reaction mixture by capillary
GLC. In all cases, the chromatograms of samples with-
drawn from the reaction mixture in the initial moment
contained an additional peak with a retention time
matching neither initial reactants nor dienone IV; after
18–25 h, that peak was no longer detected.
Thus, the mechanism proposed previously for the
sulfanylation of activated vinylacetylenic compounds
XCH=CHC≡CR, where X is an electron-withdrawing
group [15], is likely to be general. Taking into account
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NUCLEOPHILIC SULFANYLATION OF 1,5-DISUBSTITUTED PENT-2-EN-4-YN-1-ONES
17
Table 3. Principal crystallographic data and parameters of X-ray diffraction experiments for compounds IIIa–IIIe
Parameter
IIIa
IIIb
IIIc
IIId
IIIe
CCDC entry no.
Molecular weight
933440
356.46
933441
370.49
933442
390.90
933443
435.36
933444
346.42
Crystal dimensions, mm 0.36×0.30×0.25 0.41×0.36×0.28 0.43×0.37×0.21 0.36×0.22×0.19 0.26×0.15×0.13
a, Å
09.150(7)
09.686(7)
11.084(8)
102.660
103.404
090.475
930.5(12)
1.272
09.2932(5)
10.1093(5)
11.2485(6)
105.343(1)
102.112(2)
095.263(9)
984.20(9)
1.250
09.3431(14)
10.0112(12)
11.2636(14)
105.734(4)
102.194(3)
095.255(4)
978.7(2)
09.4997(13)
10.2173(12)
11.0080(12)
104.673(3)
102.339(6)
095.837(6)
995.9(2)
11.5354(3)
09.2601(3)
33.3338(8)
90
b, Å
c, Å
α, deg
β, deg
γ, deg
V, Å3
90
90
3560.7(2)
1.292
d
calc, g/cm3
1.326
1.452
μ, mm–1
0.183
0.176
0.313
2.179
1.700
Number of independent
3627 (0.083)
5198 (0.028)
5154 (0.014)
5801 (0.018)
2875 (0.051)
reflections (Rint)
Number of observed
reflections/parameters
2275 / 235
3978 / 245
4385 / 244
5071 / 244
2232 / 226
R, % [I > 2σ(I)]
Rw, %
0.058
0.121
1.020
0.041
0.098
1.010
0.032
0.091
1.010
0.028
0.081
1.010
0.057
0.143
1.050
Goodness of fit S
interaction, which leads to change of the crystal
packing. Thus, compounds IIIa–IIId in crystal (i.e., in
the absence of solvent molecules) are characterized by
similar intermolecular interactions which determine
not only similarity of their geometries (Fig. 2) but also
isotypy of their unit cells in crystal (Table 3). In all
cases, similar C=O···H contacts with participation of
meta-hydrogen atoms in the phenyl group are observed
for compounds III with Ar2 = Ph. Electron density
redistribution in keto sulfide IIIe changes the topology
of intermolecular bonds and hence molecular geometry
(the Ar2 plane is turned through a considerable angle
with respect to the C5–C6 bond, Fig. 2), so that isotypy
in the series of the examined compounds is violated
(Table 3).
EXPERIMENTAL
The IR spectra were recorded on an FSM-1201
instrument. The NMR spectra were obtained on Bruker
AM-300 and Jeol ECX-400A instruments using tetra-
methylsilane as internal standard.
(a)
(b)
C5
C4
C5
S1
C4
S1
C2
C3
C2
C3
C1
C1
O1
O1
Fig. 2. Superpositions of (a) molecules IIIa and IIIb and (b) IIIa and IIIe. The positions of O1, C1, C2, and C3 coincide in pairs.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

GOLOVANOV et al.
The progress of reactions and the purity of products
4.04 m (2H, SCH2), 4.18 t (1H, CH, J = 7.7, 6.3 Hz),
18
7.22–7.35 m (10H, Harom), 7.55 d (2H, Harom, J =
8.5 Hz), 7.94 d (2H, Harom, J = 8.7 Hz). 13C NMR spec-
trum (100 MHz, DMSO-d6), δC, ppm: 30.5 (CH), 35.3
(SCH2), 44.2 (CH2), 84.1 and 89.3 (C≡C); 122.7,
127.6, 129.1, 129.2, 129.4, 129.5, 130.6, 131.9, 135.4,
138.4, 139.0 (Carom); 195.9 (C=O). Found, %: C 73.50;
H 4.95; S 8.11. C24H19ClOS. Calculated, %: C 73.73;
H 4.91; S 8.19.
were monitored by TLC on Sorbfil plates (ethyl
acetate–hexane, 1:2), as well as by GLC on a Kristall
4000M chromatograph equipped with a flame ioniza-
tion detector (ZB-1 capillary column, 50 m×0.25 mm,
stationary phase 100% polydimethylsiloxane, film
thickness 0.5 μm; oven temperature 230°C, injector
and detector temperature 315°C).
(E)-1,5-Diarylpent-2-en-4-yn-1-ones Ia–Ig were
3-Benzylsulfanyl-1-(4-bromophenyl)-5-phenyl-
pent-4-yn-1-one (IIId). Yield 90%, mp 81–82°C
(from Me2CO–H2O). IR spectrum (KBr), ν, cm–1: 2853
synthesized according to [18].
3-Benzylsulfanyl-1,5-diphenylpent-4-yn-1-one
(IIIa). Five drops of triethylamine were added to a sus-
pension of 1020 mg (4.4 mmol) of ketone Ia and
550 mg (4.4 mmol) of thiol IIa in 10 mL of
95% ethanol, and the mixture was stirred and left to
stand for 10 h. An oily material separated and was
ground with a glass rod to induce crystallization. The
precipitate was filtered off, washed with 50% ethanol,
and dried in air. Yield 890 mg (57%), mp 44–45°C
(from CH2Cl2–C6H14). IR spectrum (KBr), ν, cm–1:
1
(SCH2), 1688 (C=O). H NMR spectrum (500 MHz,
CDCl3), δ, ppm: 3.22–3.45 m (2H, CH2), 3.99–4.06 m
(2H, SCH2), 4.30 t (1H, CH, J = 7.0, 6.3 Hz), 7.24–
7.41 m (10H, Harom), 7.58 d (2H, Harom, J = 8.5 Hz),
7.72 d (2H, Harom, J = 8.5 Hz). Found, %: C 66.24;
H 4.74; S 7.07. C24H19BrOS. Calculated, %: C 66.21;
H 4.41; S 7.35.
3-Benzylsulfanyl-1-(furan-2-yl)-5-phenylpent-
4-yn-1-one (IIIe). Yield 81%, colorless crystals,
mp 85–86°C (from Me2CO–H2O). IR spectrum (KBr),
ν, cm–1: 2852 (SCH2), 1676 (C=O). 1H NMR spectrum
(400 MHz, CDCl3), δ, ppm: 3.16–3.37 m (2H, CH2),
3.98–4.07 m (2H, SCH2), 4.28–4.32 m (1H, CH),
6.52 d.d (1H, furan, J = 3.4, 1.6 Hz), 7.16 d (1H, furan,
J = 3.7 Hz), 7.23–7.41 m (10H, Harom). 7.58 s (1H,
furan). 13C NMR spectrum (100 MHz, DMSO-d6), δC,
ppm: 30.5 (CH), 36.0 (SCH2), 43.9 (CH2), 84.9 and
87.8 (C≡C); 112.5, 118.0, 122.9, 127.3, 128.4, 128.4,
128.7, 129.2, 131.9, 138.0, 147.0, 152.5 (Carom); 185.0
(C=O). Found, %: C 75.95; H 5.45; S 9.01. C22H18OS.
Calculated, %: C 76.28; H 5.25; S 9.24.
1
2851 (SCH2), 1690 (C=O). H NMR spectrum
(400 MHz, CDCl3), δ, ppm: 3.28–3.54 m (2H, CH2),
4.00–4.09 m (2H, SCH2), 4.35 t (1H, CH, J = 7.0 Hz),
7.24–7.34 m (6H, Harom), 7.40–7.42 m (4H, Harom),
7.46 d (2H, Harom, J = 7.8 Hz), 7.57 t (1H, Harom, J =
7.3 Hz), 7.89 d (2H, Harom, J = 7.6 Hz). Found, %:
C 81.19; H 6.06; S 8.62. C24H20OS. Calculated, %:
C 80.85; H 5.67; S 9.00.
Compounds IIIb–IIIf and IVa–IVf were synthe-
sized in a similar way.
3-Benzylsulfanyl-1-(4-methylphenyl)-5-phenyl-
pent-4-yn-1-one (IIIb). Yield 75%, mp 55–56°C
(from Me2CO–H2O). IR spectrum (KBr), ν, cm–1: 2854
3-Benzylsulfanyl-5-(4-bromophenyl)-1-phenyl-
pent-4-yn-1-one (IIIf). Yield 78%, mp 150–151°C
(from Me2CO–H2O). IR spectrum (KBr): ν 1681 cm–1
(C=O). 1H NMR spectrum (400 MHz, CDCl3), δ, ppm:
3.27–3.52 m (2H, CH2), 3.97–4.06 m (2H, SCH2),
4.31 d.d (1H, CH, J = 7.7, 6.3 Hz), 7.23–7.47 m (11H,
1
(SCH2), 1682 (C=O). H NMR spectrum (400 MHz,
CDCl3), δ, ppm: 2.41 s (3H, CH3), 3.27–3.53 m (2H,
CH2), 4.02–4.11 m (2H, SCH2), 4.38 d.d (1H, CH, J =
7.56, 6.4 Hz), 7.24–7.36 m (8H, Harom), 7.42–7.45 m
(4H, Harom), 7.81 d (2H, Harom, J = 8.2 Hz). 13C NMR
spectrum (100 MHz, DMSO-d6), δC, ppm: 21.8 (CH3),
30.6 (CH), 36.1 (SCH2), 44.1 (CH2), 84.1 and 88.4
(C≡C); 123.0, 127.3, 128.4, 128.5, 128.8, 129.2, 129.5,
131.9, 134.2, 138.2, 144.4 (Carom); 195.7 (C=O).
Found, %: C 81.06; H 6.36; S 8.31. C25H22OS. Cal-
culated, %: C 81.05; H 6.00; S 8.64.
H
H
arom), 7.57 t (1H, Harom, J = 7.3 Hz), 7.89 d (2H,
arom, J = 7.6 Hz). 13C NMR spectrum (100 MHz,
DMSO-d6), δC, ppm: 30.6 (CH), 36.1 (SCH2), 44.0
(CH2), 88.6 and 89.5 (C≡C); 121.9, 122.6, 127.4,
128.3, 128.8, 129.1, 131.6, 133.3, 133.6, 136.5, 138.0
(Carom); 195.9 (C=O). Found, %: C 65.97; H 4.35.
C24H19BrOS. Calculated, %: C 66.21; H 4.41.
3-Benzylsulfanyl-1-(4-chlorophenyl)-5-phenyl-
pent-4-yn-1-one (IIIc). Yield 89%, mp 77–78°C (from
Me2CO–H2O). IR spectrum (KBr), ν, cm–1: 2852
(E,E)- and (E,Z)-5-(4-Bromophenylsulfanyl)-1,5-
diphenylpenta-2,4-dien-1-one (IVa, isomer mixture,
1:1.5). Yield 63%, mp 75–76°C (from Me2CO–H2O).
IR spectrum (CCl4), ν, cm–1: 1660 (C=O, E,Z), 1645
1
(SCH2), 1689 (C=O). H NMR spectrum (400 MHz,
DMSO-d6), δ, ppm: 3.45–3.65 m (2H, CH2), 3.97–
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

NUCLEOPHILIC SULFANYLATION OF 1,5-DISUBSTITUTED PENT-2-EN-4-YN-1-ONES
19
1
(C=O, E,E). H NMR spectrum (400 MHz, CDCl3), δ,
ppm: 6.28 d (3-H, E,E, J = 11.7 Hz), 6.84 d (1-H, E,E,
J = 14.9 Hz), 8.23 d.d (2-H, E,Z, J = 11.2, 15.1 Hz).
Found, %: C 65.71; H 4.07. C23H17BrOS. Calculated,
%: C 65.68; H 4.08.
J = 8.2 Hz), 7.59 d (2H, Harom), 7.90 d (2H, Harom, J =
8.2 Hz), 8.29 d.d (1H, 3-H, J = 11.2, 14.9 Hz).
13C NMR spectrum (100 MHz, CDCl3), δC, ppm: 21.1
(CH3); 127.0, 128.5, 129.0, 129.3, 129.8, 130.0, 130.5,
130.6, 131.8, 136.7, 136.8, 139.0, 139.1, 141.6, 148.1
(Carom, C2, C3, C4, C5); 189.5 (C=O). Found, %:
C 73.84; H 4.87. C24H19ClOS. Calculated, %: C 73.73;
H 4.91.
(E,E)- and (E,Z)-5-(4-Bromophenylsulfanyl)-1-
(4-methylphenyl)-5-phenylpenta-2,4-dien-1-one
(IVb, isomer mixture, 1:2.7). Yield 82%, mp 119–
120°C (from Me2CO–H2O). IR spectrum (CCl4), ν,
(E,E)- and (E,Z)-5-(4-Bromophenylsulfanyl)-
1-(4-chlorophenyl)-5-phenylpenta-2,4-dien-1-one
(IVf, isomer mixture, 1:2.2). Yield 83%, mp 123–
125°C (from Me2CO–H2O). IR spectrum, ν, cm–1:
1661 (C=O, E,Z), 1638 (C=O, E,E). 1H NMR spectrum
(400 MHz, CDCl3), δ, ppm: 6.24 d (3-H, E,E, J =
11.7 Hz), 6.81 d (1-H, E,E, J = 14.7 Hz), 7.14 d (1-H,
E,Z, J = 15.1 Hz), 8.23 d.d (2-H, E,Z, J = 11.1,
15.0 Hz). Found, %: C 61.04; H 3.63. C23H16BrClOS.
Calculated, %: C 60.60; H 3.55.
cm–1: 1660 (C=O, E,Z), 1643 (C=O, E,E). H NMR
1
spectrum (400 MHz, CDCl3), δ, ppm: 6.29 d (3-H,
E,E, J = 11.7 Hz), 6.88 d (1-H, E,E, J = 14.9 Hz),
7.04 d (3-H, E,Z, J = 11.7 Hz), 7.20 d (1-H, E,Z, J =
14.9 Hz), 8.22 d.d (2-H, E,Z, J = 11.1, 15.0 Hz).
Found, %: C 66.52; H 4.52. C24H19BrOS. Calculated,
%: C 66.21; H 4.41.
(E,Z)-5-(4-Bromophenylsulfanyl)-1-(4-methoxy-
phenyl)-5-phenylpenta-2,4-dien-1-one (IVc). Yield
43%, mp 99–100°C (from Me2CO–H2O). IR spectrum
Detection of kinetically controlled adduct V. One
drop of triethylamine was added at room temperature
to a solution of 0.1 mmol of ketone I and 0.1 mmol of
benzenethiol IIb–IId in 1 mL of 95% ethanol. The
mixture was stirred, and two drops were withdrawn
from the mixture using a pipette at definite time
intervals. The solvent was evaporated from the sample,
and the oily residue was pelleted with KBr and
analyzed by IR spectroscopy (2300–1600 cm–1).
A sample for GLC analysis was withdrawn using
a microsyringe and was directly injected into the
chromatograph.
(CCl4): ν 1657 cm–1 (C=O). H NMR spectrum
1
(400 MHz, CDCl3), δ, ppm: 3.88 s (3H, CH3O), 6.96 d
(2H, Harom, J = 8.7 Hz), 7.01 d (2H, Harom, J = 8.5 Hz),
7.05 d (1H, 2-H, J = 11.5 Hz), 7.21 d (1H, 1-H, J =
14.4 Hz), 7.22–7.28 m (6H, Harom, J = 8.2 Hz), 7.59 d
(2H, Harom), 7.98 d (2H, Harom, J = 7.8 Hz), 8.20 d.d
(1H, 3-H, J = 11.5, 14.4 Hz). 13C NMR spectrum
(100 MHz, CDCl3), δC, ppm: 55.6 (CH3O); 113.9,
120.5, 128.2, 128.3, 128.6, 129.3, 130.9, 131.1, 131.3,
132, 133.4, 133.9, 138.7, 139.9, 144.9, 163.5 (Carom
,
C2, C3, C4, C5); 188.9 (C=O). Found, %: C 63.76;
H 4.30. C24H19BrO2S. Calculated, %: C 63.86; H 4.25.
X-Ray analysis of compounds IIIa–IIIe. Single
crystals of IIIa–IIIe were obtained by crystallization
from chloroform–hexane. Compounds IIIa–IIId crys-
tallized in triclinic crystal system (at 100 K), and
compound IIIe, in rhombic. Reflection intensities were
measured on a Bruker APEX II diffractometer at
100 K [λMoKα 0.71073 Å for compounds IIIa–IIId,
λCuKα 1.54178 Å for IIIe]. Space group P-1¯ (IIIa–
IIId), Pbca (IIIe). The structures were solved by the
direct methods. All non-hydrogen atoms were local-
ized by difference syntheses of electron density, and
their positions were refined against F2hkl in anisotropic
approximation. Hydrogen atoms on carbon atoms were
visualized geometrically and were refined in isotropic
approximation according to the rigid body model:
Uiso(H) = 1.5Ueq(Ci) for methyl groups and Uiso(H)
=1.2Ueq(Cii) for other carbon atoms, where Ueq(C) is
the equivalent temperature factor of the carbon atom to
which the given hydrogen atom is attached. All calcu-
lations were performed with the aid of SHELXTL 5.10
(E,E)- and (E,Z)-1-(4-Chlorophenyl)-5-phenyl-5-
phenylsulfanylpenta-2,4-dien-1-one (IVd, isomer
mixture, 1 : 2.4). Yield 82%, mp 91–93°C (from
Me2CO–H2O). IR spectrum (CCl4), ν, cm–1: 1660
1
(C=O, E,Z), 1637 (C=O, E,E). H NMR spectrum
(400 MHz, CDCl3), δ, ppm: 6.19 d (3-H, E,E, J =
11.7 Hz), 6.74 d (1-H, E,E, J = 14.7 Hz), 7.02 d (3-H,
E,Z, J = 11.2 Hz), 7.12 d (1-H, E,Z, J = 14.9 Hz),
8.27 d.d (2-H, E,Z, J = 11.2, 15.0 Hz). Found, %:
C 73.33; H 4.67. C23H17ClOS. Calculated, %: C 73.29;
H 4.56.
(E,Z)-1-(4-Chlorophenyl)-5-(4-methylphenylsul-
fanyl)-5-phenylpenta-2,4-dien-1-one (IVe). Yield
66%, mp 121–122°C (from Me2CO–H2O). IR spec-
1
trum (CCl4): ν 1660 cm–1 (C=O). H NMR spectrum
(400 MHz, CDCl3), δ, ppm: 2.19 s (3H, CH3), 6.92 d
(2H, Harom, J = 7.8 Hz), 6.97 d (1H, 2-H, J = 11.2 Hz),
7.06 d (2H, Harom, J = 8.0 Hz), 7.10 d (1H, 1-H, J =
15.3 Hz), 7.22–7.25 m (3H, Harom), 7.44 d (2H, Harom
,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

GOLOVANOV et al.
20
12. Korzhova, N.V., Korshunov, S.P., Statsyuk, V.E., and
Bodrikov, I.V., Izv. Vyssh. Uchebn. Zaved., Ser. Khim.
Khim. Tekhnol., 1982, vol. 25, p. 813.
13. Bodrikov, I.V., Korshunov, S.P., Bazhan, L.I., Sta-
tsyuk, V.E., and Korzhova, N.V., Zh. Org. Khim., 1988,
vol. 24, p. 679.
software package [23]. The principal crystallographic
data and refinement parameters are given in Table 3.
This study was performed under financial support
by the Ministry of Education and Science of the
Russian Federation (project no. 3.1168.2011).
14. Bondarev, G.N. and Petrov, A.A., Zh. Org. Khim., 1968,
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