F. Odame et al. / Journal of Molecular Structure 1216 (2020) 128302
3
2
.3.5. N-[(benzyloxy)methanethioyl]benzamide (IV)
Benzyl alcohol was added to benzoyl isothiocyanate in 1 mL of
were located on a difference Fourier map and refined freely. Data
were corrected for absorption effects using the numerical method
implemented in SADABS [12].
acetone and subjected to ultrasonic radiation for 60 min at room
temperature. The product was recrystallized and obtained as a
pale-yellow solid from DMSO: toluene (4:1). Yield ¼ 86% (ultra
2.5. Computational studies
ꢂ
1
sound) 70% (conventional method), Mp ¼ 67e68 C, H NMR
(
7
ppm): 12.09 (s, 1H), 7.90 (d, 2H, J ¼ 7.6 Hz), 7.60 (t, 1H, J ¼ 7.2 Hz),
The calculations were carried out using the Gaussian 09 pro-
gram [13]. Molecular geometries of the singlet ground state of all
the compounds were fully optimized in the gas phase at the density
functional theory (DFT) level of theory using hybrid B3LYP [14e16],
B3PW91, and wB97XD functionals together with the 6-31G (d,p)
basis set.
The B3LYP functional has been used in computing vibrational
frequencies, NMR, MEP, by Mulliken population analysis (MPA),
Hirshfeld population analysis (HPA) and Natural population anal-
ysis (NPA) schemes as well as computation of thione-thiol isomers
[17e19].
.48 (m, 4H), 7.40 (m, 3H), 5.60 (s, 2H), 1 C NMR (ppm): 189.2 (C]
3
S), 165.3 (C]O), 135.0 (PheH), 133.0 (PheH), 128.4 (PheH), 127.9
ꢁ1
(
(
(
PheH), 72.2 (CH
C]O), 1692 (C]O), 1601 (C]C), 1514 (C]C), 1489 (CeN), 1455
CeN), 1373 (CeO). Anal. calcd. for C15 S: C, 66.40; H, 4.83; S,
1.82; N, 5.16. Found: C, 66.32; H, 4.76; S, 11.79; N, 5.11. LRMS (m/z,
2
), IR (nmax, cm ): 3307 (NeH), 3244 (NeH), 1710
H13NO
2
1
þ
M ): Found for C15
H13NO
2
S ¼ 271.28, Expected mass ¼ 271.33.
2.3.6. 1-Benzoyl-3-(2-hydroxyethyl)thiourea (V)
Ethanolamine was added to benzoyl isothiocyanate in 1 mL of
acetone and subjected to ultrasonic radiation for 60 min at room
temperature. The product was recrystallized and obtained as a
colourless solid from DMSO:toluene (4:1). Yield ¼ 89% (ultra
For compound I a frequency calculation was carried out to
ensure that the optimized molecular structure corresponded to a
minimum [20], thus only positive frequencies were expected. The
HOMO and LUMO results as well as the information for bond length
and bond angles were obtained using Avogadro.
ꢂ
1
sound) 71% (conventional method), Mp ¼ 114e116 C, H NMR
(
ppm): 11.26 (s, 1H), 11.04 (s, 1H), 7.92 (d, 2H, J ¼ 7.2 Hz), 7.63 (t, 1H,
13
J ¼ 7.2 Hz), 7.56 (t, 2H, J ¼ 76 Hz) 5.05 (s, 1H), 3.04 (m, 4H) C NMR
(
ppm): 180.3 (C]S), 168.0 (C]O), 132.9 (PheH), 132.3 (PheH),
3. Results and discussion
ꢁ
1
1
28.4 (PheH), 58.4 (CH
2
), 47.5 (CH
224 (NeH), 2947 (CeH), 1668 (C]O), 1602 (C]C), 1525 (C]C),
300 (CeO). Anal.calcd. for C10 S: C, 53.55; H, 5.39; S, 14.30;
2
). IR (nmax, cm ): 3322 (NeH),
3
3.1. Synthesis
1
12 2 2
H N O
N, 12.49. Found: C, 53.48; H, 5.33; S, 14.25; N, 12.42. LRMS (m/z,
The different amine derivatives were added to benzoyl iso-
thiocyanate and subjected to ultrasonic radiation for 60 min at
room temperature. Scheme 1 gives the synthetic schemes for the
synthesis of compounds I-VI.
þ
M ): Found for C10
H
12
N
2
O
2
S ¼ 224.22, Expected mass ¼ 224.28.
2
.3.7. 3-Benzoyl-1-(1-benzylpiperidin-4-yl)thiourea (VI)
-Amino-N-benzylpiperidine was added to benzoyl isothiocya-
nate in 1 mL of acetone and subjected to ultrasonic radiation for
0 min at room temperature. The product was recrystallized and
obtained as light brown solid from DMSO:toluene (4:1).
Yield 86% (ultra sound) 76%,(conventional method)
4
3.2. Spectroscopic characterization
6
a
Signals for the NeH proton were observed between 12.98 and
10.37 ppm. Aromatic protons gave signals between 8.58 and
6.80 ppm, whilst aliphatic protons gave signals between 3.04 and
¼
ꢂ
1
Mp ¼ 112e114 C. H NMR (ppm): 10.95 (s, 1H), 7.91 (d, 2H,
13
J ¼ 7.6 Hz), 7.60 (t, 1H, J ¼ 7.2 Hz), 7.50 (s, 2H), 7.30 (s, 4H), 7.24 (m,
1.97 ppm. In the C NMR spectrum the thione signal was observed
between 180.3 and 177.6 ppm whilst the carbonyl occurred be-
tween 168.3 and 161.0 ppm. Signals for aromatic carbons were
observed between 157.6 and 148.9 ppm. Aliphatic carbon signals
were observed between 58.4 and 40.3 ppm. The IR spectrum gave
1
H), 4.22 (s, 1H), 3.47 (s, 2H), 2.65 (m, 2H), 2.17 (t, 2H), 1.97 (m, 2H),
13
1
1
.58 (q, 2H, C(5)eH)). C NMR (ppm): 178.9 (C]S), 168.2 (C]O),
38.2 (PheH), 133.0 (PheH), 131.9 (PheH), 128.8 (PheH), 128.5
PheH), 128.4 (PheH), 128.1 (PheH), 127.1 (PheH), 62.0 (CH ), 51.0
max, cm ): 3229 (NeH), 2980 (CeH), 1725
C]O), 1654 (C]O), 1509 (C]C), 1164 (CeN). Anal.calcd. for C20
(
(
(
2
ꢁ
1
ꢁ1
CH
2
), 30.0 (CH
2
). IR (
n
signals for the NeH stretch between 3322 and 3109 cm , which is
within the range reported for NeH of thiones [21]. The NeH signal
H
23
N
3
OS: C, 67.96; H, 6.56; S, 9.07; N,11.89. Found: C, 67.90; H, 6.52;
for compound I coincides with the broad OH signal hence signal
þ
ꢁ1
S, 9.02; N, 11.82. LRMS (m/z, M ): Found for C20
Expected mass ¼ 353.48.
H
23
N
3
OS ¼ 353.42,
suppression could account for the low NH value of 3109 cm . The
ꢁ1
aliphatic CeH stretch occurred between 2980 and 2810 cm . The
C]O stretch of a carbonyl was observed between 1783 and
ꢁ1
ꢁ1
and between 1669 and 1654 cm whilst the C]C
2.4. X-ray crystal structure determination
1710 cm
stretch was observed between 1598 and 1525 cm
ꢁ1
.
X-ray diffraction analyses of IV, V and VI were performed at
Table 2 gives the list of synthesized compounds and their yields.
2
00 K using a Bruker Kappa Apex II diffractometer with mono-
chromated Mo K
for data collection and [11], for cell refinement and data reduction.
The structures were solved by direct methods using SHELXSe2013
a
radiation (
l
¼ 0.71073 Å). APEXII [10], was used
3.3. Crystal structures of compounds IV, V and VI
Compounds IV, V and VI were recrystallized from DMSO:To-
luene (1:1). Compound IV was obtained as a pale yellow solid,
whilst compounds V and VI were obtained as colourless and light
brown solids respectively. The crystallographic data, selected
experimental and computed bond lengths and bond angles for the
crystal structures of compounds IV, V and VI are provided in
Tables 3, 4, 5 and 6. The ORTEP diagrams for compounds IV, V and
VI are presented in Figs. 1e3. Compound IV crystallized in the
orthorhombic space group Iba2, whilst compounds V and VI crys-
tallized in the monoclinic space group P21/c (see Table 5) (see
Table 6).
[
[
10] and refined by least-squares procedures using SHELXL-2013
11], with SHELXLE [10], as a graphical interface. All non-
hydrogen atoms were refined anisotropically. Carbon-bound H
atoms were placed in calculated positions (CeH 0.95 Å for aromatic
carbon atoms and CeH 0.99 Å for methylene groups) and were
included in the refinement in the riding model approximation, with
Uiso (H) set to 1.2Ueq (C). The H atoms of the methyl groups were
allowed to rotate with a fixed angle around the CeC bond to best fit
the experimental electron density (HFIX 137 in the SHELX program
suite [11]) with Uiso (H) set to 1.5Ueq (C). Nitrogen-bound H atoms