2,4-Diaryl-1,3-chalcogen azoles bearing pentafluorosulfanyl SF5 groups: A synthetic and structural study

Article abstract of DOI:10.1021/jo500316v

A series of new 2,4-diaryl-1,3-chalcogen azoles having pentafluorosulfanyl SF₅ functional groups has been prepared by means of the two-component cyclization of the selenoamide or thioamide with α-bromoketones. The selenoamides or thioamides were obtained from the reaction of Woollins' reagent or Lawesson's reagent with 4-pentafluorosulfanylbenzonitrile, followed by hydrolysis with water. All new compounds were characterized by ¹H, ¹³C, ⁷⁷Se, ¹⁹F NMR spectroscopy, and accurate mass measurement. X-ray crystal structure analysis of the selenoamide, thioamide, and 2,4-diarylpentafluorosulfanyl-1,3-chalcogen azoles reveal that the selenoamide and thioamide have very similar structural features along with similar intermolecular interactions such as the π-π stacking and the weak N-H...E (E = S or Se) hydrogen bonding. The 2,4-diarylpentafluorosulfanyl- 1,3-chalcogen azoles show the newly formed five-membered N(1)-C(2)-E(3)-C(4)- C(5) ring is either perfectly planar (and coplanar with two peripheral aryl ring planes) or near-planar. The π-π intermolecular interactions and the weak C-H...π and C-H...X (X = Br, F, O) hydrogen bonding are discussed in the cases of 2,4-diarylpentafluorosulfanyl-1,3-chalcogen azoles.

Full text of DOI:10.1021/jo500316v

Article
pubs.acs.org/joc
2,4-Diaryl-1,3-Chalcogen Azoles Bearing Pentafluorosulfanyl SF5
Groups: A Synthetic and Structural Study
Guoxiong Hua, Junyi Du, Alexandra M. Z. Slawin, and J. Derek Woollins*
EaStCHEM School of Chemistry, University of St Andrews, Fife, KY16 9ST, U.K.
S
* Supporting Information
ABSTRACT: A series of new 2,4-diaryl-1,3-chalcogen azoles having penta-
fluorosulfanyl SF5 functional groups has been prepared by means of the two-
component cyclization of the selenoamide or thioamide with α-bromoketones.
The selenoamides or thioamides were obtained from the reaction of Woollins’
reagent or Lawesson’s reagent with 4-pentafluorosulfanylbenzonitrile, followed
1
by hydrolysis with water. All new compounds were characterized by H, 13C,
77Se, 19F NMR spectroscopy, and accurate mass measurement. X-ray crystal
structure analysis of the selenoamide, thioamide, and 2,4-diarylpentafluoro-
sulfanyl-1,3-chalcogen azoles reveal that the selenoamide and thioamide have
very similar structural features along with similar intermolecular interactions
such as the π−π stacking and the weak N−H···E (E = S or Se) hydrogen
bonding. The 2,4-diarylpentafluorosulfanyl-1,3-chalcogen azoles show the
newly formed five-membered N(1)−C(2)-E(3)-C(4)−C(5) ring is either
perfectly planar (and coplanar with two peripheral aryl ring planes) or near-planar. The π−π intermolecular interactions and the
weak C−H···π and C−H···X (X = Br, F, O) hydrogen bonding are discussed in the cases of 2,4-diarylpentafluorosulfanyl-1,3-
chalcogen azoles.
surfactants,12 and successful incorporation of SF5 substituent
INTRODUCTION
■
into an antimalarial drug was developed.13 In addition,
Organic compounds bearing pentafluorosulfanyl (SF5) are
selenium-containing heterocyclic compounds have gradually
recognized as special organic derivatives of sulfur hexafluoride
increased interest in recent years because of their diverse
SF6, because in both SF6 and SF5 derivatives, the sulfur atom is
reactivity and pharmaceutical applications. In particular, the
hypervalent and has a hexacoordinated state with an octahedral
selenazole derivatives are of marked interest due to their
geometry. The pentafluorosulfanyl (SF5) substituent, recently
antitumor, antibacterial and other notable activities.14 Because
labeled as the “substituent of the future”, occupies a special
distinctive properties can be found in both types of the
place due to its remarkable chemical stability and uniqueness.
compounds, we anticipate that the selenozoles combined with a
In recent years, organofluorine compounds bearing strongly
electron-withdrawing and highly lipophilic pentafluorosulfanyl
(SF5) group have attracted much attention from synthetic
SF5 fragment have the potential to exhibit much better activity
than any single type of the above-mentioned compounds. This
expectation stimulated us to synthesize the new type of
organic and medicinal chemists because of its unique high
selenazoles and thiazoles. Herein, we report a very simple route
electronegativity, substantial steric effect, low surface energy,
to prepare a series of novel 1,3-selenazoles and 1,3-thiazoles
incorporating a pentafluorosulfanyl-aryl SF5C6H4 group and
significant hydrophobicity, and high chemical and metabolic
stability.1,2 The pentafluorosulfanyl SF5 group has some
their single crystal X-ray structural profiles. To the best of our
resemblance to the trifluoromethyl CF3, though it is even
knowledge, this is the first report of a systematic synthesis and
more electronegative and sterically demanding.3 Thus, SF5-
containing compounds overtake the corresponding CF3-
containing compounds in altering molecular properties such
X-ray single crystal structures of 2,4-diaryl-1,3-chalcogen azoles
bearing a pentafluorosulfanyl SF5 group.
as density, refractive index, dipole moment, lipophilicity,
RESULTS AND DISCUSSION
■
thermal and chemical stability, and they have a distinct impact
on biological activity.4 Since the first synthesis of pentafluoro-
Synthesis. Synthetic approaches to nitrogen- and sulfur-
sulfanylbenzene was reported nearly 50 years ago,5 a number of
containing heterocyclic compounds have been extensively
explored,15 but methods for the synthesis of their selenium
SF5-group-containing compounds have become available so
far,1a,6 and consequently, wide applications such as super-
analogues have not been appreciably studied due mainly to the
conductivity, metallic conductivity, semiconductivity,7 herbi-
difficulty associated with the availability of the primary
cides,8 enzyme inhibitors,9 liquid crystals,10 and energetic
materials11 have been explored. Recently, SF5 functional
Received: February 10, 2014
aliphatic compounds were used as starting materials for
Published: March 28, 2014
© 2014 American Chemical Society
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Scheme 1. Synthesis of Selenoamide 1 and 1,3-Selenazoles 2−9 (X and Ar Groups Defined in Table 1)
Scheme 2. Synthesis of Thioamide 10 and 1,3-Thiazoles 11−13 (X and Ar Groups Defined in Table 1)
Table 1. Yields, 19F and 77Se NMR Data of Compounds 1−13
compd
X
Ar
yield (%)
19F NMR (δ, ppm)
77Se NMR (δ, ppm)
2
2
1
2
87
99
98
95
90
94
97
89
97
61
93
91
99
82.3 (pentet, J = 150.4 Hz, 1F) 61.7 (d, J = 149.7 Hz, 4F)
766.1
734.5
742.6
725.8
739.9
727.0
746.7
724.7
734.6
2
2
Br
Br
Br
Br
Br
Br
Br
Cl
4-ClC6H4
83.2 (pentet, J = 152.3 Hz, 1F) 62.0 (d, J = 149.5 Hz, 4F)
2
2
3
3-NO2C6H4
83.0 (pentet, J = 153.3 Hz, 1F) 61.9 (d, J = 149.8 Hz, 4F)
2
2
4
4-CH3OC6H4
3,4-di-ClC6H3
4-CH3C6H4
84.3 (pentet, J = 152.1 Hz, 1F) 62.0 (d, J = 149.8 Hz, 4F)
2
2
5
83.1 (pentet, J = 150.4 Hz, 1F) 62.0 (d, J = 149.8 Hz, 4F)
2
2
6
83.3 (pentet, J = 151.7 Hz, 1F) 62.0 (d, J = 149.9 Hz, 4F)
2
2
7
4-NO2C6H4
83.0 (pentet, J = 151.6 Hz, 1F) 61.9 (d, J = 149.6 Hz, 4F)
2
2
8
2,5-di-CH3OC6H3
2,4-di-ClC6H3
83.4 (pentet, J = 149.0 Hz, 1F) 62.1 (d, J = 149.8 Hz, 4F)
2
2
9
83.1 (pentet, J = 149.0 Hz, 1F) 62.0 (d, J = 149.9 Hz, 4F)
2
2
10
11
12
13
82.3 (pentet, J = 150.4 Hz, 1F) 61.7 (d, J = 149.7 Hz, 4F)
2
2
Br
Br
Br
4-NO2C6H4
82.3 (pentet, J = 153.3 Hz, 1F) 61.7 (d, J = 149.7 Hz, 4F)
2
2
2,5-di-CH3OC6H3
4-BrC6H4
83.4 (pentet, J = 150.5 Hz, 1F) 62.0 (d, J = 149.6 Hz, 4F)
2
2
83.2 (pentet, J = 150.7 Hz, 1F) 61.9 (d, J = 149.8 Hz, 4F)
selenocarboxamides,16 which are typically used as important
precursors for the synthesis of the selenium−nitrogen rich
heterocycles.17,18 In general, the methods for the synthesis of
selenoamides involve the reaction of nitrile with H2Se,
NaSeH,16d derived from NaBH4/Se16d,e,19, Se/CO,20 or
tris(trimethylsilyl)monoselenophosphate,21 Another method
involves the reaction of nitrile with Al2Se3 in the presence of
Et3N/pyridine/H2O22 or with P2Se5 in the presence of EtOH/
H2O.17 These synthetic methods need toxic/not readily
available reagents. We have previously reported a highly
efficient approach for the preparation of a series of primary
aryl-selenoamides from the reaction of arylnitriles with
Woollins’ reagent, followed by treatment with water.23
Therefore, by using this documented method, 4-pentafluoro-
sulfanylbenzoselenoamide 1 was prepared in 87% yield by the
reaction of 4-pentafluorosulfanylbenzonitrile and Woollins’
reagent, followed by hydrolysis with water. Then cyclization
of selenoamide 1 with an equivalent of α-haloketones gave a
series of 1,3-selenazoles 2−9 (Scheme 1) in excellent yields, as
shown in Table 1. The lower yields of 1,3-selenazoles 5 (90%)
and 8 (89%) could be attributed to the steric hindrance of the
two substituents (methoxy groups) in one of the phenyl rings.
All new compounds 1−9 are yellow or white or purple
crystalline solids which are soluble in common organic solvents.
stretch and an absorption band in the range of 593−584 cm−1,
which might be assigned to the ν(Se−C) vibration.16f,24,25 The
1H NMR spectra consist of a strong single peak of the sole
azole proton in the range of 8.19−8.83 ppm and the 19F NMR
spectra comprise a quintet pattern for one F atom and a
doublet pattern for the other four F atoms in SF5 group (more
details shown in the Experimental Section). The spectroscopic
data for 2−9 provide support for the formulation of these
compounds. It is worth noting that the 77Se NMR chemical
shift values are in the range of 724.5−746.7 ppm in 1,3-
selenazoles 2−9 and are significantly lower than that in their
starting material selenoamide 1 (766.1 ppm) (Table 1). In
general, more electron-withdrawing groups result in higher 77Se
chemical shifts.
Similarly, four sulfur analogues, thioamide 10 and 1,3-
thiazoles 11−13, were also prepared following the same general
procedure as the preparation of compounds 1−9. 4-Penta-
fluorosulfanylbenzothioamide 10 was obtained in 61% yield by
the reaction of 4-pentafluorosulfanylbenzonitrile and Law-
esson’s reagent, followed by treatment with water. Further
treating thioamide 10 with an equivalent of α-haloketones
afforded the corresponding 1,3-thiazoles 11−13 in excellent
yields, as shown in Scheme 2 and Table 1. Once again, new
compounds 10−13 are yellow or white crystalline solids, which
are soluble in common organic solvents. In their mass spectra,
we observed the anticipated [M + H]+ or [M + Na]+ peak, and
satisfactory accurate mass measurements were found for all
compounds. A strong single peak of the sole azole proton at the
range of 7.49−8.02 ppm in the 1H NMR spectra of compounds
11−13 was observed, and we note that the values are obviously
1
Compounds 1−9 were characterized by H, 13C, 19F, and 77Se
NMR spectroscopy, IR spectroscopy, and mass spectrometry.
All compounds showed the anticipated [M + H]+ or [M + Na]+
peak in their mass spectra and satisfactory accurate mass
measurements. The IR spectra of compounds 2−9 show an
absorption band between 1508−1606 cm−1 due to v(C−N)
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Table 2. Details of the X-ray Data Collections and Refinements for Compounds 1−6
compound
formula
1
2
3
4
5
6
C7H6F5NSSe
310.14
monoclinic
P21/c
C15H9ClF5NSSe
444.71
orthorhombic
Pnma
C15H9F5N2O2SSe
455.26
C16H12F5NO2SSe
440.29
monoclinic
C2/c
C15H8Cl2F5NSSe
479.15
C16H12F5NSSe
424.29
orthorhombic
Pna21
Mw
crystal system
triclinic
P-1
monoclinic
P21/n
space group
a/Å
17.608(10)
5.871(2)
10.079(4)
90
12.536(3)
6.791(4)
18.646(4)
90
7.911(11)
10.43(2)
11.61(2)
109.181(3)
109.09(12)
100.490(13)
808(2)
35.77(5)
6.207(8)
15.93(3)
90
15.288(8)
5.682(3)
19.113(10)
90
7.789(9)
33.34(4)
6.278(8)
90
b/Å
c/Å
α
β
106.40(2)
90
90
107.03(2)
90
101.98(11)
90
90
γ
90
90
U/A3
999.6(6)
4
1587.3(5)
4
3381(8)
8
1624.1(15)
4
1630(4)
4
Z
2
μ/cm−1
40.036
8097
27.154
15 600
1972
25.194
24.003
20 519
5631
28.204
24.81
reflections collected
10 284
11 719
17 000
5227
independent reflections
1146
5146
2854
Rint
0.1404
0.0621
0.1745
0.1126
0.0590
0.1102
0.0810
0.0717
0.0714
0.2290
0.1759
0.1299
0.0629
0.1899
R1
0.0599
0.0718
wR2 [I > 2σ(I)]
0.1479
0.2210
Table 3. Details of the X-ray Data Collections and Refinements for Compounds 7, 8, 10−13
compound
formula
7
8
10
11
12
13
C15H9F5N2O2SSe
455.26
orthorhombic
P212121
6.761(5)
12.748(8)
18.642(12)
90
C17H14F5NO2SSe
470.32
C7H6F5NS2
263.24
monoclinic
P21/c
C15H9F5N2O2S2
408.36
orthorhombic
Pnma
C17H14F5NO2S2
423.42
monoclinic
P21/c
C15H9F5BrNS2
442.26
orthorhombic
Pnma
Mw
crystal system
triclinic
P-1
space group
a/Å
9.650(4)
12.717(6)
15.930(7)
77.557(13)
75.92(11)
77.43(2)
1823(2)
4
17.361(6)
5.7603(16)
9.950(3)
90
12.889(8)
6.737(4)
18.371(12)
90
12.075(10)
9.345(7)
16.111(13)
90
12.804(3)
6.7729(16)
18.485(4)
90
b/Å
c/Å
α
β
90
106.615(7)
90
90
106.76(3)
90
90
γ
90
90
90
U/A3
1607(2)
4
953.4(5)
4
1595.1(18)
4
1741(3)
4
1603(6)
4
Z
μ/cm−1
25.35
22.354
5.98
4.019
3.697
28.817
13 170
1536
reflections collected
13 869
3765
23 912
11 794
1717
11 651
1528
12 559
3056
independent reflections
11 731
Rint
0.0747
0.0544
0.1681
0.0478
0.1463
0.1210
0.3179
0.0782
0.0495
0.1504
0.1227
0.1192
0.3828
0.1718
0.0567
0.1550
R1
0.0553
wR2 [I > 2σ(I)]
0.1658
smaller than those (8.19−8.83 ppm) in compounds 2−9. Not
surprisingly, the 19F NMR spectra comprise two typical
patterns (a quintet pattern for one F atom and a doublet
pattern for another four F atoms) for the SF5 group in
compounds 11−13.
X-ray Single-Crystal Structures. Crystals of compounds
1−8 and 10−13 suitable for X-ray crystallographic analysis
were grown by diffusion of a dichloromethane solution of the
compound into hexane at room temperature in each case. All
structures have a single molecule of the compound in the
asymmetric unit, the exception being compound 8, which
contains two independent molecules with mirror symmetry.
Crystal data and structure refinement for compounds 1−8 and
10−13 are summarized in Tables 2 and 3. Selected bond
lengths and angles are listed in Tables 4−6.
longer than that in literature values [1.270(7)−1.324(8) Å].30
The selenoamide functionality is not particularly coplanar with
the aryl backbone, with the selenium atom lying 0.263 Å from
the aryl ring plane and with the Se(1)−C(1)−N(1) mean plane
inclining by 16.7° from the aryl ring plane in this case. In
thioamide 10, the conformation is quite similar to selenoamide
1, and the bond distances for CS and C−N are 1.679(7) and
1.321(9) Å, respectively, which are very close to the literature
values for the thioamides.31,32 The thioamide functionality is
not coplanar with the phenyl backbone with the sulfur atom
lying 0.274 Å from the phenyl ring plane and the S(1)−C(1)−
N(1) plane inclined by 19.2° from the phenyl mean plane.
However, it is interesting to note that in both 1 and 10, the
pentafluorosulfanyl SF5 group is arranged with the equatorial
S−F bonds essentially bisecting the aryl plane as previously
proposed to be energetically favorable33 and in accord with the
strongly electron-withdrawing and highly lipophilic properties
of the pentafluorosulfanyl (SF5) group. The sulfur atom of the
SF5 group has octahedral coordination geometry for both
The CSe bond length in compound 1 (Figure 1) is
1.828(8) Å, which is within the range of ordinary CSe bond
distances in other selenoamides [1.81(5)−1.856(4) Å],23,26−30
whereas the C−N bond distance [1.328(11) Å] is marginally
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In both 1 and 10, there are hydrogen bond interactions
between the primary amine hydrogen atoms of one molecule
and the S or Se atom of another molecule resulting in a “infinite
chain” framework built from the basic dimer unit as shown in
Figure 2. The N−H···Se distance is 2.779 Å, and Se···N is 3.490
Å, and along with the angle N−H···Se 126.4°, these are the
typical motifs for hydrogen bonding in primary selenoa-
mides.23,30 It is interesting to note that strong hydrogen
bonding is observed in 10, cf. 1, in which the N−H···S distance
is 2.615 Å and S···N 3.303(6) Å, with the N−H···S angle being
127.4°.
Table 4. Selected Bond Distances [Å] and Angles [°] for
Compounds 1 and 10 (* E = Se or S)
1
10
E1*−C7
N1−C7
C4−C7
S1−F1
S1−F2
S1−F3
S1−F4
S1−F5
1.828(8)
1.328(11)
1.484(11)
1.592(7)
1.586(5)
1.570(7)
1.585(5)
1.586(5)
1.679(7)
1.321(9)
1.492(12)
1.587(4)
1.604(4)
1.587(4)
1.564(4)
1.570(5)
The supramolecular assemblies in 1 and 10, forming three-
dimensional networks, were built by the N−H···E (S or Se)
hydrogen bonds and π-systems as shown in Figure 3. “Head-to-
head” pairs of molecules are linked by paired N−H···E (S or
Se) hydrogen bonds to form the centrosymmetric pair unit.
The centrosymmetric pair unit is the key building block for the
network conformation held together by strong π−π stacking
interaction leading to the three-dimensional network motifs.
The SF5 groups of molecules in adjacent tapes pack together,
although there are no close contacts between the SF5 group and
the other surrounding functional groups.
The crystal characteristics of compounds 2−8 and 11−13,
despite their rather similar molecular formulas, are all
somewhat different. Thus, compounds 2, 5, 6, 7, 8, 11, 12,
and 13 are assigned to seven different space groups (Pnma, P-1,
C2/c, P21/n, Pna21, P212121, and P21/c, respectively) belonging
to three different space systems (monoclinic, orthorhombic,
and triclinic space systems). Surprisingly, the structures 2, 11,
and 13 show the newly formed five-membered N(1)−C(2)−
E(3)−C(4)−C(5) rings being a perfectly planar arrangement,
which is also coplanar with two peripheral aryl ring planes. The
E1−C7-N1
E1−C7-C4
N1−C7−C4
F1−S1−F2
F1−S1−F3
F1−S1−F4
F1−S1−F5
F2−S1−F3
F2−S1−F4
F2−S1−F5
F3−S1−F4
F3−S1−F5
F4−S1−F5
119.7(6)
121.4(6)
123.2(6)
117.0(7)
90.0(3)
176.4(3)
88.7(3)
88.1(3)
90.6(3)
175.4(3)
87.9(3)
90.5(3)
88.4(3)
87.7(3)
121.5(5)
117.1(6)
89.8(2)
175.9(3)
90.3(2)
88.2(2)
89.5(2)
176.8(3)
88.0(3)
90.2(2)
87.8(2)
88.8(2)
compounds. In 10, the bond distances of S−Fax 1.570(5) Å; S−
Feq 1.587(4), 1.604(4), 1.587(4), 1.564(4) Å; the bond angles
of Fax−S−Feq 88.2(2), 88.0(3), 87.8(2), 88.8(2)°; Feq−S−Feq
89.8(2), 90.3(2), 89.5(2), 90.2(2)° and the C−S bond distance
of 1.679(7) Å are comparable to that in the analogous 3-
pentafluorosulfanylbenzoic acid,34 3-acetamidopentafluoro-
sulfanylbenzene, and 4-acetamidopentafluorosulfanylbenzene.35
Table 5. Selected Bond Distances [Å] and Angles [°] for Compounds 2−6
2
3
4
5
6
N1−C2
N1−C5
C2−E3
E3−C4
C4−C5
S1−F1
S1−F2
S1−F3
1.295(7)
1.388(7)
1.890(6)
1.837(6)
1.346(8)
1.573(3)
1.572(4)
1.593(4)
1.572(4)
1.573(3)
1.293(5)
1.385(6)
1.893(6)
1.839(4)
1.375(7)
1.576(5)
1.572(4)
1.559(5)
1.589(4)
1.585(4)
1.308(5)
1.398(6)
1.905(5)
1.829(5)
1.388(7)
1.583(4)
1.592(5)
1.589(5)
1.591(4)
1.587(4)
1.299(13)
1.398(15)
1.894(11)
1.830(11)
1.344(15)
1.574(7)
1.575(6)
1.567(7)
1.571(6)
1.579(7)
1.310(9)
1.399(9)
1.918(8)
1.876(8)
1.381(10)
1.591(5)
1.602(6)
1.587(5)
1.587(5)
1.594(5)
a
a
S1−F4
S1−F5
N1−C2−E3
C2-E3-C4
E3−C4−C5
C4−C5−N1
C5−N1−C2
F1−S1−F2
F1−S1−F3
F1−S1−F4
F1−S1−F5
F2−S1−F3
F2−S1−F4
F2−S1−F5
F3−S1−F4
F3−S1−F5
F4−S1−F5
114.2(4)
114.2(4)
114.6(4)
113.1(8)
113.6(5)
84.0(3)
112.3(5)
116.3(5)
113.2(5)
89.97(17)
174.58(18)
88.95(17)
87.16(15)
84.8(2)
110.9(4)
116.7(3)
113.5(4)
89.5(2)
85.0(2)
111.2(4)
117.0(4)
112.2(4)
89.6(3)
84.4(5)
113.1(9)
114.9(4)
114.4(9)
89.8(4)
175.4(5)
89.4(4)
87.6(4)
89.6(4)
175.2(4)
87.8(4)
90.9(4)
87.9(4)
87.4(3)
84.5(3)
111.2(6)
116.1(6)
114.6(6)
91.0(3)
175.5(3)
89.5(3)
87.7(3)
89.2(3)
175.4(3)
89.9(3)
87.8(3)
89.9(3)
87.8(3)
a
a
174.89(17)
89.2(2)
175.59(18)
89.7(3)
87.32(18)
91.0(3)
87.7(2)
a
90.6(2)
90.3(3)
a
174.58(18)
87.48(15)
89.95(17)
87.48(15)
87.16(15)
175.4(2)
87.76(19)
89.9(2)
175.55(19)
87.5(2)
a
a
a
90.1(3)
87.61(18)
87.82(18)
87.9(2)
88.1(2)
a
E: Se or S; F2A and F1A in compound 2 correspond to the respective F3 and F4 in compounds 3−8, 12.
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Table 6. Selected Bond Distances [Å] and Angles [°] for Compounds 7, 8, 11−13
7
8
11
12
13
N1−C2
N1−C5
C2−E3
E3−C4
C4−C5
S1−F1
S1−F2
S1−F3
1.310(7)
1.392(7)
1.875(6)
1.828(7)
1.375(8)
1.572(5)
1.579(5)
1.585(6)
1.581(6)
1.584(4)
1.308(4)[1.304(5)]
1.390(6)[1.393(5)]
1.891(4)[1.889(3)]
1.851(4)[1.852(5)]
1.368(6)[1.377(5)]
1.571(3)[1.581(4)]
1.582(3)[1.579(4)]
1.592(3)[1.576(4)]
1.577(3)[1.591(4)]
1.583(4)[1.585(3)]
113.5(3)[114.3(3)]
84.67(17)[84.56(15)]
111.9(3)[111.7(3)]
115.4(3)[115.4(4)]
114.5(3)[114.1(3)]
90.06(17)[90.0(2)]
174.2(2)[175.30(18)]
89.96(19)[89.4(2)]
87.44(18)[87.3(2)]
88.62(16)[90.5(2)]
174.72(18)[175.36(16)]
87.19(16)[87.92(19)]
90.84(18)[89.7(2)]
86.88(17)[88.03(19)]
87.54(17)[87.45(19)
1.299(5)
1.378(6)
1.728(4)
1.673(6)
1.376(7)
1.575(3)
1.575(3)
1.578(3)
1.578(3)
1.585(3)
1.299(13)
1.391(14)
1.735(10)
1.701(11)
1.395(12)
1.588(6)
1.608(5)
1.596(6)
1.596(6)
1.589(8)
1.295(12)
1.361(10)
1.723(9)
1.670(9)
1.386(13)
1.569(5)
a
a
a
a
1.576(6)
1.576(6)
a
S1−F4
S1−F5
1.569(5)
1.588(6)
N1−C2−E3
C2−E3−C4
E3−C4−C5
C4−C5−N1
C5−N1−C2
F1−S1−F2
F1−S1−F3
F1−S1−F4
F1−S1−F5
F2−S1−F3
F2−S1−F4
F2−S1−F5
F3−S1−F4
F3−S1−F5
F4−S1−F5
113.2(4)
113.3(3)
114.9(8)
113.8(7)
85.9(3)
111.0(5)
115.9(5)
114.0(5)
90.2(3)
174.3(3)
89.7(3)
86.9(3)
88.9(3)
174.9(3)
86.9(3)
90.7(3)
87.4(3)
88.0(3)
90.1(2)
89.6(5)
110.5(8)
113.6(9)
111.3(8)
89.6(3)
174.9(4)
90.9(3)
87.9(4)
89.6(3)
175.2(4)
87.0(4)
89.5(3)
87.0(4)
87.3(4)
90.3(5)
110.1(7)
114.3(8)
111.5(8)
90.0(2)
174.1(3)
88.7(3)
86.8(2)
90.7(3)
174.1(3)
87.4(2)
111.4(4)
112.9(4)
112.3(4)
a
a
a
a
90.57(17)
174.78(14)
89.73(14)
87.70(13)
89.73(14)
174.78(14)
a
a
a
a
a
a
87.6(2)
a
a
89.3(3)
90.0(32)
87.4(2)
87.1(2)
a
a
87.1(2)
86.8(2)
a
E: Se or S; F1A, F2A and F2 in compound 11 correspond to the respective F2, F3, and F4 in compounds 3−8, 12; F3A and F1A in compound 13
correspond to the respective F2 and F4 in compounds 3−8, 12.
Figure 1. Single crystal X-ray structures of selenoamide 1 and thioamide 10.
Figure 2. Molecular structures of 1 (a) and 10 (b) showing the atom-labeling scheme and the intermolecular N−H···Se and N−H···S hydrogen
bonds (dashed line).
similar motifs could be seen in previously reported 1,3-
selenazoles.36 However, the newly formed five-membered
N(1)−C(2)−E(3)−C(4)−C(5) rings in structures of 3, 4, 5,
6, 7, 8 and 12 adopt the near-planar conformation with
chalcogen (Se or S) atom being 0.006, 0.007, 0.009, 0.005,
0.005, 0.005[0.003], and 0.001 Å, respectively, out of the
N(1)−C(2)−E(3)−C(4)−C(5) mean plane with the two
peripheral aryl ring planes having dihedral angles of 16.48,
18.86, 11.61, 21.64, 6.19, 12.58(3.62), 11.52°, respectively. For
all structures of 3, 4, 5, 6, 7, 8, and 12, the dihedral angles
between the newly formed five-membered ring N(1)−C(2)−
E(3)−C(4)−C(5) mean planes and the SF5-attaching aryl ring
planes varying from 1.81 to 20.39° indicate the apparent effect
of the peripheral aryl rings with different substituents.
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SF5 resulting in an additional component to the overall dipole
moment in the direction of the long molecular axis.37
The C−Se bond distances in structures of 2−8 differ from
1.828(7) to 1.918(8) Å, covering the range of C−Se bond
lengths found in the reported 1,3,4-selenadiazoles [1.87−1.90
Å];30,38−40 however, these values are marginally shorter than
those expected for a typical C−Se single bond (ca. 1.92−1.94
Å). In addition, the CN bond lengths in these structures
differing from 1.293(5) to 1.310(9) Å and the C−N bond
distances ranging from 1.385(6) to 1.399(9) Å are close to the
reported 1,3-seleazoles [1.268(11) Å for the CN bond and
1.384(11) Å for the C−N];16f however, these values are
significantly shorter than the usual C−N single bond length of
1.47 Å,36,41,42 indicating clearly that some degree of
delocalization is present. The C−Se−C angles in structures of
2−8 [84.0(3)−85.9(3)°] are marginally wider than that in the
reported similar structure [83.3(5)°].16f The results further
support the assertion of a special effect of the peripheral SF5
group within the molecules.
When compared to the above structures of 2−8, their sulfur
analogous structures of 11−13 have obvious differences in C−S
and C−N bond lengths and C−S−C angles. The C−S bond
distances ranging from 1.670(9) to 1.701(11) Å and the CN
and C−N bond lengths differing from 1.295(12) to 1.299(13)
Å and 1.361(10) to 1.391(14) Å, respectively, are in good
agreement with those observed in the similar structures.43,44
However, the C−S bond lengths are considerately shorter, and
the C−S−C angles altering from 89.6(5) to 90.3(5)° are much
wider than that in their selenium counterparts (Figure 4).
Although the similarity of molecular geometries and types of
intramolecular interactions might lead to similar packing motifs,
this is not found in each case. The intermolecular interactions,
namely, π−π interactions and weak C−H···O hydrogen
bonding and C−H···F hydrogen bonding and C−H···Br close
contacts, combined in a different way, give a variety of packing
networks. In 4, the layer-like network consists of the crossed-
layer-like “three molecules group” and the “two molecules
group”, which are built up by the π−π interaction, the weak C−
H···O hydrogen bonding, and the weak C−H···F hydrogen
bonding, leading to the three-dimensional motif network. The
situation in the case of 13 is somewhat different. The sheet
network comprises a “single molecule sheet”, which is linked
together by the weak C−H···Br hydrogen bonding and the
weak C−H···F hydrogen bonding, C−H···π interaction, and
π−π interaction, resulting in the different three-dimensional
motif network (Figures 5 and 6).
Figure 3. Views of the three-dimensional network in 1 (c) and 10 (d)
formed by the combination of N−H···E (S or Se) hydrogen bonding
and π-stacking.
In summary, Woollins’ reagent or Lawesson’s reagent reacts
with an equivalent of 4-pentafluorosulfanylbenzonitrile, and
when followed by treatment with water, the reaction led to the
corresponding 4-pentafluorosulfanylbenzoselenoamide (1) and
4-pentafluorosulfanylbenzothioamide (10) in good yields. The
cyclization of primary 4-pentafluorosulfanylbenzoselenoamide
or 4-pentafluorosulfanylbenzothioamide with α-haloketones
afforded a variety of new 2,4-diaryl-1,3-selenazoles 2−9 and
2,4-diaryl-1,3-thiazoles 11−13 in excellent yields. The
structures of all new compounds have been elucidated by
The equatorial planes of the SF5 group having an umbrella
shape canting toward the fifth axial fluorine atom in all
structures, as previously reported with the SF5 group.34 The Fax
and S atoms in structures of 2, 3, 7, 11, and 13 are coplanar
with the adjacent aryl ring planes. Although the observed
deviations of Fax and S atoms out of the adjacent aryl ring
planes in structures of 5, 6, 8 range from 0.020−0.179 Å,
0.015−0.097 Å, respectively. Two exceptions are structures of 4
and 12, only the Fax atom in structure of 4 is coplanar with the
adjacent aryl ring plane with the S atom being 0.030 Å from the
aryl ring plane. By contrast, the S atom in structure of 12 is
coplanar with the adjacent aryl ring plane, and the Fax atom is
0.030 Å out of this plane. The results may explain the relatively
high dipole moment of the aromatic pentafluorosulfanyl group
1
using H, 13C, 77Se, 19F NMR spectroscopy, and accurate mass
measurement. Ten single-crystal structures were investigated. 4-
Pentafluorosulfanylbenzoselenoamide (1) and 4-penta-
fluorosulfanylbenzothioamide (10) have very close structural
similarity along with similar intermolecular interactions, with
π−π stacking and the weak N−H···E (E = S or Se) hydrogen
bonding. However, 1,3-selenazoles 2−9 and 1,3-thiazoles 11−
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Figure 4. Single crystal X-ray structures of 1,3-selenazoles 2−8 and 1,3-thiazoles 11−13.
13 display a diverse story of molecular configuration and
intermolecular interaction information. The structures of 2, 11,
and 13 show the newly formed five-membered N(1)−C(2)−
E(3)−C(4)−C(5) rings being perfectly planar and also
coplanar with two substituent aryl ring planes. However,
near-planar conformations were observed for the newly formed
five-membered N(1)−C(2)−E(3)−C(4)−C(5) rings in the
other seven structures. Typical π−π intermolecular interactions
and the weak C−H···π and C−H···X (X = Br, F, O) hydrogen
bonding have been highlighted in two cases of 4 and 13 for
their packing configurations.
EXPERIMENTAL SECTION
■
Unless otherwise stated, all reactions were carried out under an oxygen
free nitrogen atmosphere using predried solvents and standard Schlenk
techniques, and subsequent chromatographic and workup procedures
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Figure 5. View of the three-dimensional network, which makes up the
structure in 4, formed by three sets of hydrogen bonds: C−H···O
hydrogen bonding (shown as red dashed line), C−H···N hydrogen
bonding (shown as orange dashed line), and C−H···F hydrogen
bonding (shown as green dashed line), as well as the π−π interaction
which connects them into a three-dimensional network.
were performed in air. 1H (270 MHz), 13C (67.9 MHz), and 77Se-{1H}
(51.4 MHz referenced to external Me2Se) NMR spectra were recorded
at 25 °C (unless stated otherwise). 19F NMR spectra were recorded at
25 °C (unless stated otherwise) and were referenced to CFCl3 as the
external standard. Chemical shifts are reported in parts per million
(ppm), and coupling constants (J) are given in Hertz (Hz). IR spectra
were recorded as KBr pellets in the range of 4000−250 cm−1.
X-ray crystal structures were determined for compounds 1−8 and
10−13 at −148(1) °C45 with SHINE optic using Mo Kα radiation (k
= 0.71073 A). The data were corrected for Lorentz, polarization, and
absorption. The data were collected and processed using Crystal-
Clear.46 The structures were solved by direct methods47 and expanded
using Fourier techniques.48 Hydrogen atoms were refined using the
riding model. All calculations were performed using the CrystalStruc-
ture49 and SHELXL 97.50 These data can be obtained free of charge
via www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge
Crystallographic Data center, 12 Union Road, Cambridge CB2 1EZ,
UK; fax (+44) 1223−336−033; e-mail: deposit@ccdc.cam.ac.uk.
CCDC 1 992938, 2 985909, 3 989010, 4 985911, 5 992939, 6
985913, 7 985914, 8 985915, 10 992940, 11 992941, 12 985918, 13
992942.
Figure 6. View of the three-dimensional network in 13. (e) A view of a
three-dimensional layer-like network. (f) A view of the network clearly
displaying C−H···Br close contacts (shown as the red dashed line) and
C−H···F (shown as the green dashed line) contacts, as well as the C−
H···π interaction and π−π interaction, which lead into the three-
dimensional network.
1629(s), 1428(s), 1308(m), 1263(m), 1198(m), 1146(m), 1099(m),
891(s), 836(vs), 699(m), 669(m), 637(m), 601(s), 573(m); 1H NMR
(CD2Cl2, δ) 8.77 (s, 2H,), 7.92 (d, J(H,H) = 8.8 Hz, 2H,), 7.77 (d,
J(H,H) = 8.8 Hz, 2H,) ppm; 13C NMR (CD2Cl2, δ) 205.7, 127.0,
126.4, 126.3, 126.2 ppm; 77Se NMR (CD2Cl2, δ) 766.1 ppm; 19F
2
NMR (CD2Cl2, δ) 82.3 (quintet, J(F,F) = 150.4 Hz, 1F), 61.7 (d,
2J(F,F) = 149.7 Hz, 4F) ppm; MS (APCI+, m/z) 312 [M + H]+;
accurate mass measurement (APCI+, m/z): [M + H]+ Calcd for
C7H6F5SNSeH 311.9379; Found 311.9376.
General Procedure for the Synthesis of Compounds 2−9. A
mixture of α-haloketones (1.0 mmol) in 20 mL of ethanol was added
dropwise to a refluxing solution of 4-pentafluorosulfanylbenzo-
selenoamide (0.263 g, 1.0 mmol) in 20 mL of ethanol in the course
of 1 h. The reaction mixture was then allowed to reflux for another 1 h.
After the mixture was cooled to room temperature, it was concentrated
by a rotary evaporator. The residue was neutralized with 5% aqueous
ammonia (30 mL) and extracted with dichloromethane (30 mL × 3),
combined the organic layers, washed with water (20 mL × 3), and
dried over MgSO4. After we filtered and dried the sample to remove
solvent in vacuo, the organic residue was purified by a silica gel column
(1:9 ethyl acetate/dichloromethane) to give the expected products 2−
9.
Synthesis of 4-Pentafluorosulfanylbenzoselenoamide (1).23
A mixture of 4-pentafluorosulfanylbenzonitrile (0.458 g, 2.0 mmol)
and Woollins’ reagent (1.07 g, 2.0 mmol) in 20 mL of dry toluene was
refluxed for 8 h. After the reaction mixture was cooled to 90 °C, 1.0
mL of water was added, and the reaction mixture was allowed to
continue refluxing for another 1 h. After cooling the reaction mixture
to room temperature, it was concentrated to ca. 5.0 mL in vacuo,
extracted with dichloromethane (20 mL × 3), combined the
dichloromethane solution, and dried over MgSO4. After we filtered
and dried the sample to remove the solvent, the organic residue was
purified by a silica gel column (9:1 ethyl acetate/dichloromethane) to
give the expected compounds 1 as a bright yellow solid (0.270 g) in
87% isolated yield: mp, 148−150 °C; selected IR (KBr, cm−1)
4-(4′-Chlorophenyl)-2-(4″-pentafluorosulfanylphenyl)-1,3-
selenazole (2). Purple solid (0.440 g) in 99% isolated yield; mp,
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170−172 °C; selected IR (KBr, cm−1) 1595(m), 1508(m), 1481(s),
1402(m), 1284(m), 1091(s), 1043(m), 1012(m), 958(m), 821(vs),
738(m), 658(m), 587(s); 1H NMR (CD2Cl2, δ) 8.24 (s, 1H), 8.06 (d,
J(H,H) = 8.3 Hz, 2H), 7.94 (d, J(H,H) = 8.5 Hz, 2H), 7.83 (d, J(H,H)
= 8.5 Hz, 2H), 7.41 (d, J(H,H) = 8.3 Hz, 2H) ppm; 13C NMR
(CD2Cl2, δ) 171.4, 156.2, 139.0, 133.9, 133.6, 129.0, 128.0, 127.1,
126.8, 126.7, 120.8 ppm; 77Se NMR (CD2Cl2, δ) 734.5 ppm; 19F
(d, J(H,H) = 8.5 Hz, 2H), 7.85 (d, J(H,H) = 8.5 Hz, 2H) ppm; 13C
NMR (CD2Cl2, δ) 172.1, 155.1, 147.3, 140.7, 138.7, 127.3, 127.2,
127.0, 126.9, 126.8, 124.2 ppm; 77Se NMR (CD2Cl2, δ) 746.7 ppm;
19F NMR (CD2Cl2, δ) 83.0 (quintet, 2J(F,F) = 151.6 Hz, 1F), 61.9 (d,
2J(F,F) = 149.6 Hz, 4F) ppm; MS (APCI+, m/z) 457 [M + H]+;
accurate mass measurement (APCI+, m/z) [M + H]+ Calcd for
C15H9O2N2F5SSeH 456.9543; Found 456.9532.
2
NMR (CD2Cl2, δ) 83.2 (quintet, J(F,F) = 152.3 Hz, 1F), 62.0 (d,
4-(2′,5′-Dimethoxy)-2-(4″-pentafluorosulfanylphenyl)-1,3-
selenazole (8). Off-white solid (0.417 g) in 89% isolated yield: mp,
104−106 °C; selected IR (KBr, cm−1) 1606(m), 1501(s), 1462(m),
1439(m), 1403(m), 1315(m), 1261(m), 1214(m), 1181(m),
1158(m), 1096(m), 1048(s), 829(vs), 762(m), 723(m), 657(m),
593(s); 1H NMR (CD2Cl2, δ) 8.72 (s, 1H), 8.05 (d, J(H,H) = 8.0 Hz,
2H), 7.95 (s, 1H), 7.79 (d, J(H,H) = 8.0 Hz, 2H), 6.94 (d, J(H,H) =
8.8 Hz, 1H), 6.87 (d, J(H,H) = 8.8 Hz, 1H), 3.89 (s, 3H), 3.83 (s, 3H)
ppm; 13C NMR (CD2Cl2, δ) 168.8, 153.8, 153.1, 151.5, 139.3, 127.1,
125.5, 124.4, 121.3, 119.8, 112.6, 56.0, 55.7 ppm; 77Se NMR (CD2Cl2,
2J(F,F) = 149.5 Hz, 4F) ppm; MS (APCI+, m/z) 446 [M + H]+;
accurate mass measurement (APCI+, m/z): [M + H]+ Calcd for
C15H9ClF5NSSeH 445.9300; Found 445.9294.
4-(3′-Nitrophenyl)-2-(4″-pentafluorosulfanylphenyl)-1,3-se-
lenazole (3). Dark purple solid (0.446 g) in 98% isolated yield: mp,
138−140 °C; selected IR (KBr, cm−1) 1600(m), 1527(s), 1482(m),
1403(m), 1347(s), 1278(m), 1099(m), 966(m), 851(vs), 822(vs),
1
741(m), 660(m), 598(m), 584(m); H NMR (CD2Cl2, δ) 8.83 (s,
1H), 8.43 (s, 1H), 8.34−8.08 (m, 3H), 7.86 (d, J(H,H) = 8.8 Hz, 2H),
7.63 (d, J(H,H) = 8.8 Hz, 2H) ppm; 13C NMR (CD2Cl2, δ) 172.1,
154.9, 148.9, 138.8, 136.5, 132.4, 129.9, 127.2, 126.9, 126.8, 122.7,
122.6, 121.5 ppm; 77Se NMR (CD2Cl2, δ) 742.6 ppm; 19F NMR
(CD2Cl2, δ) 83.0 (quintet, 2J(F,F) = 153.3 Hz, 1F), 61.9 (d, 2J(F,F) =
149.8 Hz, 4F) ppm; MS (APCI+, m/z) 457 [M + H]+; accurate mass
measurement (APCI+, m/z): [M + H]+ Calcd for C15H9F5N2O2SSeH
456.9543; Found 456.9536.
4-(4′-Methoxyphenyl)-2-(4″-pentafluorosulfanylphenyl)-
1,3-selenazole (4). Pale yellow solid (0.420 g) in 95% isolated yield:
mp, 106−108 °C; selected IR (KBr, cm−1) 1604(s), 1525(m),
1511(m), 1483(m), 1461(m), 1402(m), 1302(m), 1254(s), 1175(m),
1028(m), 959(m), 844(vs), 745(m), 665(m), 640(m), 586(s); 1H
NMR (CD2Cl2, δ) 8.50 (s, 1H), 8.10 (d, J(H,H) = 8.5 Hz, 2H), 7.91
(d, J(H,H) = 8.5 Hz, 2H), 7.82 (d, J(H,H) = 7.2 Hz, 2H), 6.95 (d,
J(H,H) = 7.2 Hz, 2H), 3.83 (s, 3H) ppm; 13C NMR (CD2Cl2, δ)
170.9, 159.8, 139.3, 131.2, 130.5, 128.0, 127.1, 126.7, 118.4, 114.1,
113.7, 55.4 ppm; 77Se NMR (CD2Cl2, δ) 725.8 ppm; 19F NMR
(CD2Cl2, δ) 84.3 (quintet, 2J(F,F) = 152.1 Hz, 1F), 62.0 (d, 2J(F,F) =
149.8 Hz, 4F) ppm; MS (APCI+, m/z) 442 [M + H]+; accurate mass
measurement (APCI+, m/z): [M + H]+ Calcd for C16H12ONF5SSeH
441.9798; Found 441.9787.
2
δ) 724.7 ppm; 19F NMR (CD2Cl2, δ) 83.4 (quintet, J(F,F) = 149.0
Hz, 1F), 62.1 (d, 2J(F,F) = 149.8 Hz, 4F) ppm; MS (APCI+, m/z) 472
[M + H]+; accurate mass measurement (APCI+, m/z): [M + H]+
Calcd for C17H14F5NO2SSeH 471.9903; Found 471.9899.
4-(2′,4′-Dichloro)-2-(4″-pentafluorosulfanylphenyl)-1,3-sele-
nazole (9). Pale yellow solid (0.467 g) in 97% isolated yield: mp, 94−
96 °C; selected IR (KBr, cm−1) 1587(m), 1481(m), 1449(m),
1403(m), 1261(m), 1107(m), 1029(m), 957(m), 849(vs), 821(vs),
1
658(m), 591(s); H NMR (CD2Cl2, δ) 8.50 (s, 1H), 8.03 (d, J(H,H)
= 8.3 Hz, 2H), 7.84 (s, 1H), 7.82 (d, J(H,H) = 8.3 Hz, 2H), 7.35 (d,
J(H,H) = 8.8 Hz, 1H), 7.33 (d, J(H,H) = 8.8 Hz, 1H) ppm; 13C NMR
(CD2Cl2, δ) 163.3, 153.0, 141.7, 132.8, 130.2, 127.3, 127.2, 126.9,
126.8, 126.7, 126.2 ppm; 77Se NMR (CD2Cl2, δ) 734.6 ppm; 19F
2
NMR (CD2Cl2, δ) 83.1 (quintet, J(F,F) = 149.0 Hz, 1F), 62.0 (d,
2J(F,F) = 149.9 Hz, 4F) ppm; MS (APCI+, m/z) 480 [M + H]+;
accurate mass measurement (APCI+, m/z): [M + H]+ Calcd for
C15H8Cl2F5NSSeH 479.8908; Found 479.8899.
Synthesis of 4-Pentafluorosulfanylbenzothioamide (10). A
mixture of 4-pentafluorosulfanylbenzonitrile (0.458 g, 2.0 mmol) and
Lawesson’s reagent (0.808 g, 2.0 mmol) in 20 mL of dry toluene was
refluxed for 10 h. After the mixture was cooled to 90 °C, 1.0 mL of
water was added, and the mixture was subjected to refluxing for
another 1 h. After the reaction mixture was cooled to room
temperature, it was concentrated to ca. 5.0 mL and extracted with
dichloromethane (20 mL × 3), combined the dichloromethane
solution, and dried over MgSO4. After we filtered and dried the sample
to remove solvent, the organic residue was purified by a silica gel
column (9:1 ethyl acetate/dichloromethane) to give 0.341 g of the
compounds 10 as greenish yellow solid (61%): mp, 136−137 °C;
selected IR (KBr, cm−1) 1632(s), 1423(s), 1323(m), 1276(m),
1145(m), 1099(m), 899(m), 836(vs), 728(m), 673(m), 641(m),
4-(3′,4′-Dichlorophenyl)-2-(4″-pentafluorosulfanylphenyl)-
1,3-selenazole (5). Pale purple solid (0.430 g) in 90% isolated yield:
mp, 115−117 °C; selected IR (KBr, cm−1) 1508(m), 1475(m),
1401(m), 1307(m), 1252(m), 1128(m), 1099(m), 1051(m), 964(m),
1
836(vs), 744(m), 729(m), 665(m)m 590(s); H NMR (CD2Cl2, δ)
8.27 (s, 1H), 8.13 (s, 1H), 8.05 (d, J(H,H) = 9.1 Hz, 2H), 7.85−7.79
(m, 3H), 7.50 (d, J(H,H) = 8.5 Hz, 1H) ppm; 13C NMR (CD2Cl2, δ)
171.7, 154.9, 135.0, 132.9, 131.9, 130.8, 128.6, 127.2, 126.9, 126.8,
126.7, 125.9, 121.8 ppm; 77Se NMR (CD2Cl2, δ) 739.9 ppm; 19F
2
NMR (CD2Cl2, δ) 83.1 (quintet, J(F,F) = 150.4 Hz, 1F), 62.0 (d,
2J(F,F) = 149.8 Hz, 4F) ppm; MS (APCI+, m/z) 480 [M + H]+;
1
602(m), 576(m); H NMR (CD2Cl2, δ) 7.91 (d, J(H,H) = 8.3 Hz,
accurate mass measurement (APCI+, m/z) [M + H]+ Calcd for
C15H9NCl2F5SSeH 479.8908; Found 479.8891.
2H), 7.75 (d, J(H,H) = 8.3 Hz, 2H), 7.30 (s, 2H) ppm; 13C NMR
(CD2Cl2, δ) 200.5, 142.2, 129.2, 127.3, 126.2 ppm; 19F NMR
(CD2Cl2, δ) 82.3 (quintet, 2J(F,F) = 150.4 Hz, 1F), 61.7 (d, 2J(F,F) =
149.7 Hz, 4F) ppm; MS (APCI+, m/z) 264 [M + H]+; accurate mass
measurement (APCI+, m/z): [M + H]+ Calcd for C7H6F5NS2H
263.9935; Found 263.9936.
4-(4′-Methylphenyl)-2-(4″-pentafluorosulfanylphenyl)-1,3-
selenazole (6). Pale purple solid (0.400 g) in 94% isolated yield: mp,
152−154 °C; selected IR (KBr, cm−1) 1507 (m), 1480(s), 1448(m),
1400(m), 1296(m), 1227(m), 1098(m), 1041(m), 958(s), 838(vs),
824(vs), 742(s), 668(m), 588(s), 521(m); 1H NMR (CD2Cl2, δ) 8.19
(s, 1H), 8.07 (d, J(H,H) = 8.3 Hz, 2H), 7.88 (d, J(H,H) = 8.3 Hz,
2H), 7.83 (d, J(H,H) = 8.8 Hz, 2H), 7.26 (d, J(H,H) = 8.8 Hz, 2H),
2.38 (s, 3H) ppm; 13C NMR (CD2Cl2, δ) 171.0, 157.5, 139.3, 138.3,
132.3, 129.5, 129.1, 128.6, 127.1, 126.6, 119.6, 21.1 ppm; 77Se NMR
General Procedure for the Synthesis of Compounds 11−13.
A mixture of α-haloketones (1.0 mmol) in 20 mL of ethanol was
added dropwise to a refluxing solution of 4-pentafluorosulfanylbenzo-
thioamide (0.263 g, 1.0 mmol) in 20 mL of ethanol in the course of 1
h. The reaction mixture was then refluxed for another 1 h. After the
mixture was cooled to room temperature, it was concentrated by a
rotary evaporator. The residue was neutralized with 5% aqueous
ammonia (30 mL) and extracted with dichloromethane (30 mL × 3),
combined organic layers, washed with water (20 mL × 3), and dried
over MgSO4. After we filtered and dried the sample to remove solvent,
the organic residue was purified by a silica gel column (1:9 ethyl
acetate/dichloromethane) to give the expected products 11−13.
4-(4′-Nitrophenyl)-2-(4″-pentafluorosulfanylphenyl)-1,3-
thiazole (11). Off-white solid (0.379 g) in 93% isolated yield: mp,
175−176 °C; selected IR (KBr, cm−1) 1600(s), 1518(s), 1476(m),
2
(CD2Cl2, δ) 727.0 ppm; 19F NMR (CD2Cl2, δ) 83.3 (quintet, J(F,F)
2
= 151.7 Hz, 1F), 62.0 (d, J(F,F) = 149.9 Hz, 4F) ppm; MS (APCI+,
m/z) 426 [M + H]+; accurate mass measurement (APCI+, m/z): [M +
H]+ Calcd for C16H12NF5SSeH 425.9848; Found 425.9835.
4-(4′-Nitrophenyl)-2-(4″-pentafluorosulfanylphenyl)-1,3-se-
lenazole (7). Pale yellow solid (0.440 g) in 97% isolated yield: mp,
195−197 °C; selected IR (KBr, cm−1) 1597(s), 1519(s), 1483(m),
1402(m), 1343(s), 1187(m), 1109(m), 1092(m), 1045(m), 957(m),
821(vs), 731(m), 657(m), 587(s); 1H NMR (CD2Cl2, δ) 8.49 (s, 1H),
8.28 (d, J(H,H) = 8.8 Hz, 2H), 8.17 (d, J(H,H) = 8.8 Hz, 2H), 8.08
3884
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Article
1403(m), 1343(s), 1093(m), 1060(m), 981(m), 823(vs), 737(m),
645(m), 593(m), 573(m); H NMR (CD2Cl2, δ) 8.23 (d, J(H,H) =
Compounds; Akiba, K., Ed.; Wiley-VCH: New York, 1999; pp 295−
326. (e) Winter, R. W.; Gard, G. L. In Inorganic Fluorine Chemistry-
Toward the 21st Century; Thrasher, J. S.; Strauss, S. H., Eds.; American
Chemical Society: Washington, DC, 1994; pp 128−147.
(2) (a) Verma, R. D.; Kirchmeier, R. L.; Shreeve, J. M. In Advance in
Inorganic Chemistry; Sykes, A. G., Ed.; Academic Press: San Diego,
1994; pp 125−169. (b) Lentz, D.; Seppelt, K. In Chemistry of
Hypervalent Compounds; Akiba, K. Y., Ed.; Wiley-VCH: New York,
1999; p 295.
1
8.8 Hz, 2H), 8.10 (d, J(H,H) = 8.5 Hz, 2H), 8.07 (d, J(H,H) = 8.5 Hz,
2H), 7.80 (d, J(H,H) = 8.8 Hz, 2H), 7.76 (s, 1H) ppm; 13C NMR
(CD2Cl2, δ) 166.4, 154.7, 147.9, 140.2, 136.5, 129.6, 127.4, 127.2,
124.6, 124.2, 118.1 ppm; 19F NMR (CD2Cl2, δ) 82.3 (quintet, 2J(F,F)
2
= 150.4 Hz, 1F), 61.7 (d, J(F,F) = 149.7 Hz, 4F) ppm; MS (APCI+,
m/z) 409 [M + H]+; accurate mass measurement (APCI+, m/z): [M +
H]+ Calcd for C15H9F5N2O2S2H 409.0098; Found 409.0099.
4-(2′,5′-Dimethoxy)-2-(4″-pentafluorosulfanylphenyl)-1,3-
thiazole (12). Pale yellow solid (0.386 g) in 91% isolated yield: mp,
100−101 °C; selected IR (KBr, cm−1) 1679(m), 1595(m), 1495(s),
1463(m), 1440(m), 1405(m), 1273(s), 1216(m), 1161(m), 1095(m),
1052(s), 1921(m), 829(vs), 729(m), 663(m), 593(m); 1H NMR
(CD2Cl2, δ), 8.05 (d, J(H,H) = 8.5 Hz, 2H), 8.02 (s, 1H), 7.89 (s,
1H), 7.76 (d, J(H,H) = 8.5 Hz, 2H), 6.88 (d, J(H,H) = 8.8 Hz, 1H),
6.80 (d, J(H,H) = 8.5 Hz, 1H), 3.83 (s, 3H), 3.76 (s, 3H) ppm; 13C
NMR (CD2Cl2, δ), 163.3, 154.2, 152.8, 151.8, 137.1, 127.0, 123.7,
121.7, 120.2, 119.4, 115.8, 114.6, 112.8 ppm; 19F NMR (CD2Cl2, δ),
83.4 (quintet, J(F,F) = 150.5 Hz, 1F), 62.0 (d, J(F,F) = 149.6 Hz,
4F) ppm; MS (APCI+, m/z), 424 [M + H]+; accurate mass
measurement (APCI+, m/z): [M + H]+ Calcd for C17H14F5NO2S2H
424.0459; Found 424.0459.
(3) Sheppard, W. A. J. Am. Chem. Soc. 1962, 84, 3072−3076.
(4) (a) Salmon, R. Preparation of N-(4-Pentafluorosulfenylphenyl)
Pyrazoles as Insecticides and Acaricides. Patent WO 9306089 19930401,
1993. (b) Howard Jr, M. H. Arthropodicidal Pentafluorothiosubstituted
Anilides. Patent WO 9516676 A1 19950622, 1995.
(5) Sheppard, W. A. J. Am. Chem. Soc. 1962, 84, 3064−3072.
(6) (a) Thrasher, J. S.; Haufe, G. Synlett 2011, 12, 1683−1686.
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13, 1466−1469. (d) Walter, R.; Gard, G. L. J. Fluorine Chem. 2008,
129, 1041−1043. (e) Zarantonello, C.; Guerrato, A.; Ugel, E.; Bertani,
R.; Benetollo, F.; Milani, R.; Venzo, A.; Zaggia, A. J. Fluorine Chem.
2007, 128, 1449−1453. (f) Dolbier, W. R., Jr; Mohand, S. A.; Schertz,
T. D.; Sergeeva, T. A.; Cradlebaugh, J. A.; Mitani, A.; Gard, G. L.;
Winter, R. W.; Thrasher, J. S. J. Fluorine Chem. 2006, 127, 1302−1310.
(g) Winter, R. W.; Dodean, R.; Smith, J. A.; Anikumar, R.; Burton, D.
J.; Gard, G. L. J. Fluorine Chem. 2005, 126, 1202−1214. (h) Winter, R.
W.; Gard, G. L. J. Fluorine Chem. 2004, 125, 549−552. (i) Sergeeva, T.
A.; Dolbier, W. R., Jr Org. Lett. 2004, 6, 2417−2419. (j) Winter, R. W.;
Dodean, R.; Holmes, L.; Gard, G. L. J. Fluorine Chem. 2004, 125, 37−
41. (k) Ou, X.; Janzen, A. F. J. Fluorine Chem. 2000, 101, 279−283.
(l) Bowden, R. D.; Comina, P. J.; Greenhall, M. P.; Kariuki, B. M.;
Loveday, A.; Philp, D. Tetrahedron 2000, 56, 3399−3408.
(7) (a) Schlueter, J. A.; Ward, B. H.; Geiser, U.; Wang, H. H.; Kini, A.
M.; Parakka, J. P.; Morales, E.; Koo, H. J.; Whangbo, M. H.; Winter, R.
W.; Mohtasham, J.; Gard, G. L. J. Chem. Mater. 2001, 11, 2008−2013.
(b) Ward, B. H.; Schlueter, J. A.; Geiser, U.; Wang, H. H.; Morales, E.;
Parakka, J. P.; Thomas, S. Y.; Williams, J. M.; Nixon, P. G.; Winter, R.
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343−351.
2
2
4-(4′-Bromophenyl)-2-(4″-pentafluorosulfanylphenyl)-1,3-
thiazole (13). Pale yellow solid (0.438 g) in 99% isolated yield: mp,
168−169 °C; selected IR (KBr, cm−1) 1687(m), 1591(m), 1473(s),
1401(m), 1272(m), 1093(m), 1071(m), 1009(m), 982(m), 824(vs),
744(s), 643(m), 592(s), 573(m), 486(m); 1H NMR (CD2Cl2, δ), 8.04
(d, J(H,H) = 8.5 Hz, 2H), 7.80 (d, J(H,H) = 8.7 Hz, 2H), 7.77(d,
J(H,H) = 8.7 Hz, 2H), 7.52 (d, J(H,H) = 8.5 Hz, 2H), 7.49 (s, 1H,
Azole-H) ppm; 13C NMR (CD2Cl2, δ) 165.8, 156.0, 155.0, 136.8,
133.5, 132.3, 130.3, 128.4, 127.1, 122.8, 115.1 ppm; 19F NMR
2
2
(CD2Cl2, δ) 3.2 (quintet, J(F,F) = 150.7 Hz, 1F), 61.9 (d, J(F,F) =
149.8 Hz, 4F) ppm; MS (APCI+, m/z) 442 and 444 [M + H]+;
accurate mass measurement (APCI+, m/z): [M + H]+ Calcd for
C15H9BrF5NS2H 441.9353 and 443.9331; Found 441.9353 and
443.9329 .
ASSOCIATED CONTENT
■
S
* Supporting Information
1H, 13C, and 19F NMR, IR, and mass spectra of compounds 1−
13. Thermal Ellipsoid plots of the crystal structures. This
material is free of charge via the Internet at http://pubs.acs.org.
(8) (a) Sipyagin, A. M.; Enshov, V. S.; Kashtanov, S. A.; Bateman, C.
P.; Mullen, B. D.; Tan, Y. T.; Thrasher, J. S. J. Fluorine Chem. 2004,
125, 1305−1316. (b) Lim, D. S.; Choi, J. S.; Pak, C. S.; Welch, J. T. J.
Pestic. Sci. 2007, 32, 255−259.
(9) Stump, B.; Eberle, C.; Schweizer, W. B.; Kaiser, M.; Brun, R.;
Krauth-Siegel, R. L.; Lentz, D.; Diederich, F. ChemBioChem 2009, 10,
79−83.
AUTHOR INFORMATION
Corresponding Author
*E-mail: jdw3@st-and.ac.uk. Tel.: (+44)-1334-463384.
■
(10) (a) Hahn, A.; Kirsch, P. Eur. J. Org. Chem. 2005, 3095−3100.
(b) Kirsch, P.; Hahn, A. Eur. J. Org. Chem. 2006, 1125−1131.
(11) (a) Sitzmann, M. E. J. Fluorine Chem. 1991, 52, 195−199.
(b) Abe, T.; Tao, G. H.; Joo, Y. H.; Gard, G. L.; Winter, R. W.;
Shreeve, J. M. Chem.Eur. J. 2009, 15, 9897−9904.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
(12) Winter, R.; Nixon, P. G.; Gard, G. L. Langmuir 2004, 20, 5776−
5781.
We are grateful to the University of St Andrews for financial
support and the EPSRC National Mass Spectrometry Service
Centre (Swansea) for mass spectral measurements.
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L.; Roncal, N.; Milner, E. E. Org. Biomol. Chem. 2009, 7, 4163−4165.
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