Spectral luminescent properties of 2-aryl-5-(2,4,6-trimethylphenyl)-1Н-1,3,4-oxadiazoles

Article abstract of DOI:10.1134/S1070428017050281

Reaction of aroylhydrazides with 2,4,6-trimethylbenzoyl chloride in the presence of Et₃N afforded N-(mesityl)aroylhydrazides, which through subsequent cyclization at treatment with SOCl₂ resulted in 2-aryl-5-(2,4,6-trimethylphenyl)-1Н-1,3,4-oxadiazoles. For 2-hydroxyphenyl derivative containing a stable O–H N intramolecular bond a low quantum luminescence yield is observed (φ 0.006–0.038) due to the nonradiative deactivation of the agitated state by ESPIT mechanism.

Full text of DOI:10.1134/S1070428017050281

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2017, Vol. 53, No. 5, pp. 808–811. © Pleiades Publishing, Ltd., 2017.
Original Russian Text © Yu.M. Artyushkina, I.E. Mikhailov, G.A. Dushenko, O.I. Mikhailova, Yu.V. Revinskii, O.N. Burov, S.V. Kurbatov, 2017, published in
Zhurnal Organicheskoi Khimii, 2017, Vol. 53, No. 5, pp. 789–792.
SHORT
COMMUNICATIONS
Spectral Luminescent Properties
of 2-Aryl-5-(2,4,6-trimethylphenyl)-1Н-1,3,4-oxadiazoles
Yu. M. Artyushkinaa,b, I. E. Mikhailova,c,* G. A. Dushenkoa,c, O. I. Mikhailovac,
Yu. V. Revinskiia, O. N. Burovb, and S. V. Kurbatovb
a Southern Scientific Center of Russian Academy of Sciences, pr. Chekhova 41, Rostov-on-Don, 344006 Russia
*e-mail: mikhail@ipoc.sfedu.ru
b Southern Federal University, Rostov-on-Don, Russia
c Research Institute of Physical and Organic Chemistry, Southern Federal University, Rostov-on-Don, Russia
Received December 21, 2016
Abstract—Reaction of aroylhydrazides with 2,4,6-trimethylbenzoyl chloride in the presence of Et3N afforded
N-(mesityl)aroylhydrazides, which through subsequent cyclization at treatment with SOCl2 resulted in 2-aryl-5-
(2,4,6-trimethylphenyl)-1Н-1,3,4-oxadiazoles. For 2-hydroxyphenyl derivative containing a stable O–H N
intramolecular bond a low quantum luminescence yield is observed (φ 0.006–0.038) due to the nonradiative
deactivation of the agitated state by ESPIT mechanism.
DOI: 10.1134/S1070428017050281
2,5-Diaryl-1,3,4-oxadiazoles possess a wide range
of versatile biological activity [1], and also interesting
photophysical properties [2] that allow making on their
basis organic [3, 4] and metal complex [5] lumino-
phores, capable of effective radiation in a shortwave
region of visible spectrum [6]. In this connection
extending the range of such compounds and exploring
their spectral luminescent properties is an actual task.
due to π→π* electron transitions indicating the
existence of these compounds in solutions as benzoic
1
structures of type 3. IR and Н NMR spectra of
oxadiazoles 3a–3c are consistent with their benzoic
structures, and in the case of compound 3b they
indicate the presence of a stable intramolecular hydrogen
bond between ortho-phenol hydroxy group and the
nearest nitrogen atom of the azole ring (O–H N).
Namely, in the IR spectrum of 2-(2-hydroxyphenyl)-5-
(2,4,6-trimethylphenyl)-1Н-1,3,4-oxadiazole 3b a wide
band of OH group absorption is present at 3439 cm–1
typical of intramolecular hydrogen bonds that is absent
in compounds 3a and 3c. More than that, the presence
of a stable intramolecular hydrogen bond O–H N in
oxadiazole 3b is indicated by the shift of the stretching
vibrations of the C2=N3 bond (1627 cm–1) to the region
of low frequencies by 20 and 13 cm–1 as compared to
To this end we prepared by the reaction of
hydrazides 1a–1c with 2,4,6-trimethylbenzoyl chloride
in the presence of triethylamine benzoylbenzohydra-
zides 2a–2c, which at subsequent cyclization with
thionyl chloride afforded 2-aryl-5-(2,4,6-trimethyl-
phenyl)-1Н-1,3,4-oxadiazoles 3a–3c.
In absorption spectra of oxadiazoles 3a–3c a maximum
of longwave band is observed at 261–311 nm which is
R
O
O
R
O
R
N
N
O
Et3N
SOCl2
N
N
NHNH2
+
H
H
O
Cl
2a_2c
3a_3c
1a_1c
R = H (a), OH (b), OMe (c).
808

SPECTRAL LUMINESCENT PROPERTIES
809
similar absorption in IR spectra of oxadiazoles 3a
(1647 cm–1) and 3c (1640 cm–1), in which this
interaction is not present. In Н NMR spectrum of
oxadiazole 3b in CDCl3 a downfield shift of the signal
of the hydroxy group proton (10.31 ppm) is observed
phenyl)-1Н-1,3,4-oxadiazol 3b by phenyl or ortho-
methoxyphenyl group blocks the ESIPT process in
oxadiazoles 3a and 3c. As a result they show a strong
radiation in the shortwave region of visible spectrum
with spectral luminescent characteristics, allowing
classing them among widely popular organic
luminophores of oxadiazole series.
1
that also evidences the presence of
intramolecular hydrogen bond.
a stable
N'-Benzoyl-2,4,6-trimethylbenzohydrazide (2a).
To solution of 1.36 g (10 mmol) of benzohydrazide 1а
in 20 mL of dried acetonitrile at stirring was added in
succession 5 mL of triethylamine and 2.01 g (11 mmol)
of 2,4,6-trimethylbenzoyl chloride in 30 mL of dried
acetonitrile. The reaction mixture was left for 24 h at
room temperature and afterwards it was boiled for 3 h.
The solvent was removed in a vacuum, oily residue
was washed with water (2 × 10 mL), dried in air, the
reaction product was isolated by column chromato-
graphy on silica gel (0.063–0.200 mm, eluent ethyl
acetate–petroleum ether, 1 : 2), collecting fraction with
Rf 0.75. After distilling off the solvent the residue was
recrystallized from 2-propanol (2 × 15 mL). Yield 2.40 g
(85%), colorless crystals, mp. 203–204°С (mp. 202–
205°С [15, 16]). IR spectrum (KBr), ν, cm–1: 3240,
3174 (NH); 1685, 1637 (C=O); 1616, 1599 (C=C);
1551, 1516, 1489, 1461, 1448, 1379, 1259, 1243,
In the luminescence spectra of oxadiazole 3b two
bands are present: a shortwave (λmfalx 354–397 nm, φ
0.002–0.035) with a normal (4219–6965 cm–1) and a
fl
max
longwave (λ
476–491 nm, φ 0.001–0.004) with
abnormally high (11460–12081 cm–1) Stocks shift. By
fluorescence excitation spectra the shortwave
luminescence was assigned to the initial benzoic
structure 3b, and the longwave band, to the emission
of short-lived phototautomer resulting from a proton
transfer in the excited state from phenol hydroxyl to
the nitrogen atom of oxadiazole bound to it with the
intramolecular hydrogen bond by ESIPT mechanism
(excited-state intramolecular proton transfer) [7, 8].
The low summary quantum yield of oxadiazole 3b
luminescence (φ 0.006–0.038) is caused by the
nonradiative deactivation of its excited state by ESIPT
mechanism. Previously such effects were discovered in
spectra of ortho-hydroxyphenyl-1,3,4(1,2,4)-oxadi-
azoles [9–11] and 1,2,4-triazoles [12] structurally
similar to compound 3b.
1
1170, 1103, 1070, 1027, 1002, 986, 847, 784, 782. Н
NMR spectrum (CDCl3), δ, ppm: 2.28 s (3H, 4-CH3),
2.35 s (6H, 2,6-CH3), 6.86 s (2Harom), 7.48 d.d (2Harom
,
In 2-phenyl- and 2-(2-methoxyphenyl)derivatives
3a and 3c the ESIPT process is impossible due to the
lack of mobile proton of ortho-phenol hydroxy group
in its molecules; as a result in their luminescence
J1 7.9, J2 7.5 Hz), 7.52 d.d (1Harom, J1 7.5, J2 1.4 Hz),
7.83 d.d (2Harom, J1 7.9, J2 1.5 Hz), 8.63 d (1H, NH, J
2.5 Hz), 9.45 d (1H, NH, J 2.5 Hz). 13C NMR spectrum
(CDCl3), δ, ppm: 19.92 (2,6-CH3), 21.16 (4-CH3),
123.85 (Сarom.quat.), 126.89 (Сarom), 128.24 (2Сarom),
129.12 (Сarom), 131.55 (Сarom.quat.), 131.82 (Сarom),
135.11 (2Сarom.quat.), 139.21 (Сarom.quat.), 168.33 (С=O),
173.34 (С=O). Found, %: С 72.25; Н 6.44; N 9.97.
С17H18N2O2. Calculated, %: С 72.32; Н 6.43; N 9.92.
spectra only one highly intensive shortwave
fl
max
luminescence band (λ 349–360 nm, φ 0.30–0.98) is
present that undergoes slight shift into the red region
with increasing solvent polarity (5–6 nm), and also
with electron-donor character of the aryl substituent in
the position 2 of oxadiazole ring (by 2–4 nm). The
highest quantum luminescence yield for compounds 3a
and 3c is observed in acetonitrile (φ 0.86, 0.98), and
the lowest, in DMSO (φ 0.30, 0.68). Such effects are
also observed in the spectra of 8-hydroxy-2-
styrylquinolines at substitution of mobile proton of
phenol group by methyl or benzyl substituent [13, 14].
As a result, as in the case of 3a and 3c, a significant
increase in the luminescence quantum yield occurs in
the corresponding alkyl derivatives compared to initial
compounds.
N'-(2-Hydroxybenzoyl)-2,4,6-trimethylbenzo-
hydrazide (2b) was obtained similarly from hydrazide
of salicylic acid 1b. Yield 2.33 g (78%), colorless
crystals, mp. 140–142°С. IR spectrum (KBr), ν, cm–1:
3421 (OH); 3294, 3270 (NH); 1685, 1654 (C=O);
1640, 1613, 1598 (C=C); 1540, 1490, 1488, 1378,
1350, 1291, 1257, 1215, 1162, 1151, 1103, 1050,
1
1035, 979, 951, 889, 847, 828. Н NMR spectrum
(DMSO-d6), δ, ppm: 2.46 s (3H, 4-CH3), 2.54 s (6H,
2,6-CH3), 7.10 s (2Harom), 7.14–7.23 m (2Harom), 7.67
d.d (1Harom, J1 7.6, J2 7.5 Hz), 8.18 d.d (1Harom, J1 7.6,
J2 7.5 Hz), 10.28 d (1H, NH, J 4.5 Hz), 10.88 d (1H,
NH, J 4.5 Hz), 12.31 s (1Н, ОН). 13C NMR spectrum
Hence, the replacement of the ortho-phenol
substituent in 2-(2-hydroxyphenyl)-5-(2,4,6-trimethyl-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017

ARTYUSHKINA et al.
810
(DMSO-d6), δ, ppm: 19.42 (2,6-CH3), 21.34 (4-CH3),
114.47 (Сarom.quat.), 117.91 (Сarom), 119.46 (Сarom), 128.21
(2Сarom), 128.69 (Сarom), 133.68 (Сarom.quat.), 134.12
(Сarom), 134.94 (2Сarom.quat.), 138.11 (Сarom.quat.), 160.05
(Сarom.quat.), 168.53 (С=O), 168.94 (С=O). Found, %: С
68.49; Н 6.05; N 9.42. С17H18N2O3. Calculated, %: С
68.44; Н 6.08; N 9.39.
121.56 (Сarom.quat.), 124.52 (Сarom.quat.), 127.28 (2C,
Сarom), 129.31 (2C, Сarom), 129.51 (2Сarom), 132.08
(Сarom), 139.17 (2Сarom.quat.), 141.45 (Сarom.quat.), 164.35
(СHt,quat.), 165.26 (СHt,quat.). Found, %: С 77.31; Н 6.12;
N 10.57. C17H17N2O. Calculated, %: C 77.25; H 6.10;
N 10.60.
2-[5-(2,4,6-Trimethylphenyl)-1Н-1,3,4-oxadi-
azol-2-yl]phenol (3b) was obtained similarly. Yield
0.94 g (48%), colorless crystals, mp. 92–94°С. IR
spectrum (KBr), ν, cm–1: 3439 (OH); 1627, 1614
(C=N); 1595, 1591 (C=C); 1559, 1545, 1516, 1507,
1489, 1383, 1359, 1259, 1256, 1238, 1211, 1148,
2,4,6-Trimethyl-N'-(2-methoxybenzoyl)benzo-
hydrazide (2c) was obtained similarly from hydrazide
1с. Yield 2.53 g (81%), colorless crystals, mp. 160–
162°С. IR spectrum (KBr), ν, cm–1: 3321, 3233 (NH);
1689, 1636 (C=O); 1634, 1611, 1600, 1577 (C=C);
1508, 1507, 1484, 1470, 1460, 1434, 1317, 1294,
1250, 1183, 1157, 1120, 1018, 851. 1Н NMR spectrum
(CDCl3), δ, ppm: 2.24 s (3H, 4-CH3), 2.33 s (6H, 2,6-
CH3), 4.08 s (3H, OCH3), 6.82 s (2Harom), 6.98–7.06 m
(2Harom), 7.48 d.d (1Harom, J1 7.6, J2 7.5 Hz), 7.92 d.d
(1Harom, J1 7.6, J2 7.5 Hz), 9.53 d (1H, NH, J 7.5 Hz),
10.87 d (1H, NH, J 7.5 Hz). 13C NMR spectrum
(CDCl3), δ, ppm: 19.56(2,6-CH3), 21.45 (4-CH3),
46.23 (OCH3), 111.52 (Сarom), 118.69 (Сarom.quat.), 121.33
(Сarom), 128.36 (2Сarom), 132.30 (Сarom.quat.), 132.31
(Сarom), 133.88 (Сarom), 135.42 (2Сarom.quat.), 139.07
(Сarom.quat.), 157.76 (Сarom.quat.), 161.06 (С=O), 166.25
(С=O). Found, %: С 69.23; Н 6.44; N 9.02.
C18H20N2O3. Calculated, %: С 69.21; Н 6.45; N 8.97.
1049, 1032, 975, 850, 846, 745. UV spectrum, λmax
,
nm [ε·10–4, L/(mol·cm), λexcit 300 nm]: isooctane, 202
[8.30], 264 [3.39], 311 [2.43], λmfalx (φ) 397 (0.002), 491
fl
(0.004); acetonitrile, 258 [2.59], 308 [1.72], λ (φ)
max
fl
354 (0.005), 476 (0.001); DMSO, 307 [0.93], λ (φ)
max
1
365 (0.035), 488 (0.003). Н NMR spectrum (CDCl3),
δ, ppm: 2.39 s (6H, 2,6-CH3), 2.42 s (3H, 4-CH3), 7.03–
7.11 m (3Harom), 7.21 d (1Harom, J 7.6 Hz), 7.51 d.d
(1Harom, J1 7.6, J2 7.5 Hz), 7.82 d (1Harom, J 7.5 Hz),
10.31 s (1H, OH). 13C NMR spectrum (CDCl3), δ, ppm:
20.56 (2C, 2,6-CH3), 21.32 (4-CH3), 108.27 (Сarom.quat.),
117.65 (Сarom), 120.21 (Сarom), 120.35 (Сarom.quat.),
126.58 (Сarom), 129.06 (2Сarom), 133.66 (Сarom), 138.91
(2Сarom.quat.), 141.47 (Сarom.quat.), 157.66 (Сarom.quat.),
163.29 (СHt,quat.), 164.85 (СHt,quat.). Found, %: С 72.83;
Н 5.77; N 10.03. С17H16N2O2. Calculated, %: С 72.84;
Н 5.75; N 9.99.
2-(2,4,6-Trimethylphenyl)-5-phenyl-1Н-1,3,4-
oxadiazole (3a). A solution of 1.98 g (7 mmol) of
hydrazide 2а in 50 mL of thionyl chloride was boiled
during 5 h, then thionyl chloride was distilledoff while
heating on a water bath. Into the flask with oily residue
50 g of crushed ice was added, the precipitate was
filtered off, washed it with cold water (2 × 30 mL),
dried in open air, and purified by column
chromatography (eluent ethylcetate–petroleum ether,
1 : 5), fraction was collected with Rf 0.75–0.80. After
distilling off the solvent the residue was recrystallized
from 2-propanol. Yield 1.02 g (55%), colorless
crystals, mp. 93–94°С (mp. 92–94°С [15], 95–96°С
[16]). IR spectrum (KBr), ν, cm–1: 1647, 1610 (C=N);
1590, 1567 (C=C); 1551, 1512, 1482, 1456,
1448, 1352, 1261, 1247, 1167, 1098, 1071, 1049,
1024, 964, 867, 850, 779, 752. UV spectrum, λmax, nm
[ε·10–4 L/(mol·cm), λexcit 300 nm]: toluene, 290 [1.56],
2-[(2,4,6-Trimethylphenyl)-5-(2-methoxyphe-
nyl)]-1Н-1,3,4-oxadiazole (3c) was obtained similarly.
Yield 1.28 g (62%), colorless crystals, mp. 60–62°С.
IR spectrum (KBr), ν, cm–1: 1640, 1607 (C=N); 1591,
1572 (C=C); 1543, 1475, 1472, 1437, 1350, 1278,
1266, 1182, 1159, 1053, 1041, 1024, 968, 863, 771,
756. UV spectrum, λmax, nm [ε·10–4, L/(mol·cm), λexcit
fl
300 nm]: toluene, 305 [0.88], λ
(φ) 355 (0.69);
max
acetonitrile, 255 [1.80], 298 [0.86], λmfalx (φ) 353 (0.86);
fl
1
DMSO, 302 [0.87], λ
(φ) 360 (0.68). Н NMR
max
spectrum (CDCl3), δ, ppm: 2.32 s (9H, 2,4,6-CH3), 3.95
s (3H, OCH3), 6.96 s (2Harom), 7.03–7.11 m (2Harom),
7.49 d.d (1Harom, J1 7.6, J2 7.5 Hz), 7.98 d.d (1Harom, J1
7.5, J2 2.5 Hz). 13C NMR spectrum (CDCl3), δ, ppm:
20.94 (2,6-CH3), 21.67 (4-CH3), 56.35 (OCH3), 112.20
(Сarom), 113.67 (Сarom.quat.), 121.18 (Сarom), 121.76
(Сarom.quat.), 129.26 (2Сarom), 130.81 (Сarom), 133.37
(Сarom), 139.26 (2Сarom.quat.), 141.19 (Сarom.quat.), 158.30
(Сarom.quat.), 164.10 (СHt,quat.), 164.07 (СHt,quat.). Found,
%: С 73.41; Н 6.18; N 9.48. С18H18N2O2. Calculated,
%: С 73.45; Н 6.16; N 9.52.
fl
fl
λ
(φ) 352 (0.84); acetonitrile, 261 [2.70], λ (φ)
max
max
fl
1
349 (0.98); DMSO, 264 [1.88], λ (φ) 358 (0.30). Н
max
NMR spectrum (CDCl3), δ, ppm: 2.31 s (6H, 2,6-CH3),
2.33 s (3H, 4-CH3), 6.96 s (2Harom), 7.47–7.54 m
(3Harom), 8.06–8.15 m (2Harom). 13C NMR spectrum
(CDCl3), δ, ppm: 20.90 (2C, 2,6-CH3), 21.68 (4-CH3),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017

SPECTRAL LUMINESCENT PROPERTIES
811
7. Serdyuk, O.V., Evseenko, I.V., Dushenko, G.A.,
Revinskii, Yu.V., and Mikhailov, I.E., Russ.
J. Org. Chem., 2012, vol. 48, p. 78. doi 10.1134/
S1070428012010113
8. Doroshenko, A.O., Posokhov, E.A., Verezubo-
va, A.A., and Ptyagina, L.M., J. Phys. Org.
Chem., 2000, vol. 13, p. 253. doi 10.1002/
1099-1395(200005)13:5<253::AID-POC238>3.0.CO;2-D
9. Beldovskaya, A.D., Dushenko, G.A., Vikrishchuk, N.I.,
Popov, L.D., Revinskii, Yu.V., Mikhailov, I.E., and
Minkin, V.I., Russ. J. Org. Chem., 2013, vol. 49,
p. 1861. doi 10.1134/S1070428013120312
10. Mikhailov, I.E., Artyushkina, Yu.M., Burov, O.N.,
Dushenko, G.A., Revinskii, Yu.V., and Minkin, V.I.,
Russ. J. Gen. Chem., 2016, vol. 86, p. 406. doi 10.1134/
S1070363216020341
11. Mikhailov, I.E., Vikrishchuk, N.I., Popov, L.D.,
Dushenko, G.A., Beldovskaya, A.D., Revinskii, Yu.V.,
and Minkin, V.I., Russ. J. Gen. Chem., 2016, vol. 86,
p. 1054. doi 10.1134/S1070363216050121
12. Beldovskaya, A.D., Dushenko, G.A., Vikrishchuk, N.I.,
Popov, L.D., Revinskii, Yu.V., and Mikhailov, I.E.,
Russ. J. Gen. Chem., 2013, vol. 83, p. 2075. doi
10.1134/S1070363213110200
13. Mikhailov, I.E., Svetlichnyi, D.A., Burov, O.N.,
Revinskii, Yu.V., Dushenko, G.A., and Minkin, V.I.,
Russ. J. Gen. Chem., 2015, vol. 85, p. 1074. doi
10.1134/S1070363215050126
14. Mikhailov, I.E., Svetlichnyi, D.A., Burov, O.N.,
Dushenko, G.A., Revinskii, Yu.V., and Kurbatov, S.V.,
Russ. J. Gen. Chem., 2016, vol. 86, p. 989. doi 10.1134/
S1070363216040393
IR spectra were registered on a spectrophotometer
1
Varian Excalibur 3100 FT-IR, Н (250.13 МHz), 13С
(62.90 МHz) NMR spectra were recorded on an instru-
ment Bruker DPX-250. Absorption and fluorescent
spectra were measured on a spectrophotometer Cary Scan
100 and a spectrofluorimeter Cary Eclipse respectively.
Quantum yields of fluorescence were determined with
respect to the acetonitrile solution of anthracene [11].
ACKNOWLEDGMENTS
This study was carried out in the framework of the
State contract of the Russian Ministry of Education
and Science no. 4.129.2014/К.
REFERENCES
1. Prakash, O., Kumar, M., Kumar, R., Sharma, C., and
Aneja, K.R., Eur. J. Med. Chem., 2010, vol. 45, p. 4252.
2. Wang, G., Zhang, Y.G., Cheng, Y.X., Ma, D.G.,
Wang, L.X., Jing, X.B., and Wang, F.S., Synth. Met.,
2003, vol. 137, p. 1119.
3. Mikhailov, I.E., Vikrishchuk, N.I., Popov, L.D.,
Beldovskaya, A.D., Revinskii, Yu.V., Dushenko, G.A.,
and Minkin, V.I., RF Patent no. 2568640, 2015, Byull.
Izobret., 2015, no. 32.
4. Mikhailov, I.E., Popov, L.D., Vikrishchuk, N.I.,
Beldovskaya, A.D., Revinskii, Yu.V., Dushenko, G.A.,
and Minkin, V.I., Russ. J. Gen. Chem., 2015, vol. 85,
p. 203. doi 10.1134/S1070363215010363
5. Beldovskaya, A.D., Dushenko, G.A., Vikrishchuk, N.I.,
Popov, L.D., Revinskii, Yu.V., Mikhailov, I.E., and
Minkin, V.I., Russ. J. Gen. Chem., 2014, vol. 84, p. 171.
doi 10.1134/S1070363214010290
15. Hartmann, K.-P. and Heuschmann, M., Tetrahed-
ron, 2000, vol. 56, p. 4213. doi 10.1016/
S0040-4020(00)00346-X
6. Mikhailov, I.E., Dushenko, G.A., Starikov, D.A.,
Mikhailova, O.I., and Minkin, V.I., Vestn. YuNTs.,
2012, vol. 6, p. 32.
16. Feygelman, V.M., Walker, J.K., Katritzky, A.R., and
Dega-Szafran, Z., Chem. Scripta., 1989, vol. 29, p. 241.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017