O-benzyl-N-(2-furoyl)thiocarbamate

Article abstract of DOI:10.1023/B:JOCC.0000014694.33182.ff

The O-benzyl-N-(2-furoyl)thiocarbamate (1) was obtained by direct reaction between furoyl isothiocyanate and benzyl alcohol. The X-ray diffraction analysis of 1 showed an orthorhombic system, with a = 7.811(4) A, b = 9.685(4) A, c = 33.562(15) A, and spac

Full text of DOI:10.1023/B:JOCC.0000014694.33182.ff

Journal of Chemical Crystallography, Vol. 34, No. 2, February 2004 (�
2004)
C
O-benzyl-N-(2-furoyl)thiocarbamate
(
1)�
(
(1)
(2)
Luis Alberto Montiel-Ortega, Susana Rojas-Lima, Elena Otazo-Sanchez,
1)
and Roberto Villag o´ mez-Ibarra
Received February 5, 2003
The O-benzyl-N-(2-furoyl)thiocarbamate (1) was obtained by direct reaction between
furoyl isothiocyanate and benzyl alcohol. The X-ray diffraction analysis of 1 showed an
˚
˚
˚
orthorhombic system, with a = 7.811(4) A, b = 9.685(4) A, c = 33.562(15) A, and space
group P212121. This compound showed two different arrays of structure, corresponding to
two conformers in the same crystal unit. In one conformer the carbonyl and thiocarbonyl
groups are in a syn arrangement while in the other the groups are anti. Both structures
present a non-restricted conformation and show NH OC hydrogen bonding between them.
KEY WORDS: O-benzyl-N-(2-furoyl)thiocarbamate; conformation; thiocarbamic acid O-ester.
Introduction
carbonyl and thiocarbonyl groups towards metal-
lic ions. The O-alkyl-N-furoylthiocarbamates
Materials that can recognize ions or
present other structural alternatives because of
freebondrotationwithintheCO NH CS Omoi-
ety and they represent a new family of potential
ionophores. Their flexible structure could, in prin-
ciple, be useful to selectively complex a metallic
ion with high affinity. These ionophores could also
have improved liposolubility into the sensor mem-
brane compared to thioureas.
molecules have wide applications and are sub-
jects of intense study. For example, O-alkyl-N-
aroylthiocarbamates are useful as selective ex-
tractants of heavy metal ions in water solutions.1
These compounds are also employed in studies of
2
liquid–liquid extraction of Ag(I).
The structure of O-alkyl-N-furoylthio-
carbamates is similar to that reported for
furoylthioureas, which show good ion recogni-
To obtain more information about the struc-
ture of thiocarbamate compounds, we synthe-
sized the O-benzyl-N-(2-furoyl)thiocarbamate
(1), searching for different types of ion-
recognition materials.
3
tion properties in electrochemical sensors. How-
ever, 3-monosubstituted 1-furoylthioureas show
an intramolecular hydrogen bond that forces the
compound to adopt a rigid structure (Fig. 1),
which diminishes the chelating ability of the
Experimental section
(
1)
Centro de Investigaciones Qu ´ı micas (CIQ), Universidad
Aut o´ noma del Estado de Hidalgo, Carretera Pachuca-Tulancingo
km 4.5, Ciudad Universitaria, 42074 Pachuca, M e´ xico.
Instituto Tecnol o´ gico de Toluca (ITT). Av. Instituto Tecnologico
s/n Metepec. 52140 Toluca, M e´ xico.
O-benzyl-N-(2-furoyl)thiocarbamate
(1).
Furoyl chloride (30 mmol, 3.12 mL) was added
to a solution of KSCN (30 mmol, 2.91 g) in
dry acetone (15 mL) with magnetic stirring, at
room temperature. After 10 min, a precipitate of
(2)
�
To whom correspondence should be addressed; e-mail: luisal-
berto montiel@chemist.com.
89
1
074-1542/04/0200-0089/0 �C 2004 Plenum Publishing Corporation

9
0
Montiel-Ortega, Rojas-Lima, Otazo-Sanchez, and Villag o´ mez-Ibarra
C(4) C(54)), 118.4, 113.95 (C(3) C(53)), 112.7,
(
1
7
1
12.0 (C(2) C(52)), 148.1, 145.2 (C(1) C(51)),
2.76, 63.25 (CH O), 142.74, 135.3 (1C), 128.7,
2
1
28.5, 128.3, 126.9, 126.7 (5CH). The H NMR
13
and C NMR spectra were determined on a Jeol
eclipse +400 spectrometer at 400 and 100 MHz,
respectively, using DMSO-d and/or CDCl . The
Fig. 1. Hydrogen bonded structure reported for
-monosubstituted furoylthioureas. The anti conformer
3
6
3
is fixed.
FTIR spectra (KBr pellet or film) were recorded
in a spectrophotometer Perkin-Elmer System
2000.
KCl was filtrated and benzyl alcohol (30 mmol,
3
.06 mL) in dry acetone (20 mL) was added to the
mixture which was stirred overnight. The mixture
was poured slowly into 200 mL of ice-water with
magnetic stirring. The furoyl thiocarbamate sepa-
rated as an oily product which was extracted with
diethyl ether, dried over Na SO and purified by
Table 1 shows crystal data and the struc-
ture refinement parameters corresponding to the
X-ray diffraction analysis. The structure of 1 was
4
solved using the SHELXTL-NT program, data
reduction was carried out using the SAINT-NT5
2
4
flash chromatography (using SiO with a gradient
2
of hexane-ethyl acetate 10:0, 9:1, 8:2, etc.). The
product was collected using the 7:3 hexane-ethyl
acetate mixture, the combined fractions were
evaporated and the product crystallized as pale
yellow needles (m.p. 378 K). Spectroscopic
Table 1. Crystal Data and Structure Refinement
for O-benzyl-N-(2-furoyl)thiocarbamate
Compound
O-benzyl-N-(2-furoyl)thiocarbamate
Systematic chemical name (Furan-2-carbonyl)-thiocarbamic acid
O-benzyl ester
�
1
analysis—IR (KBr, cm )�: 3354 (NH), 3132
CCDC deposit no.
Empirical formula
Formula weight
200827
C13H11NO3S
261.29
(
CH ), 3032 (CH ), 2944 (CH ), 1581 and
ar
as
s
1
469 (C C), 1664 (C O), 1286 (COC), 1013
Crystal color and habit
Crystal system
Space group
Pale yellow/square prism
Orthorhombic
P2 2 2
(
7
furan), 1507 (thioureide I), 1196 (thioureide II),
�
1
68 (thioureide IV). IR (CHCl , cm ) �:
3
1 1 1
˚
˚
3
413 (NH), 3065 (CH ), 2977 (CH ), 2894
Unit cell dimension
a = 7.811(4) A
ar
as
(
15730 reflections
b = 9.685(4) A
(
CH ), 1603 and 1476 (C C), 1683 (C O),
s
˚
in full � range)
c = 33.562(15) A
1
286 (COC), 1011 (furan), 1509 (thioureide
3
˚
Volume, A
2539(2)
8
I), 1196 (thioureide II), 771 (thioureide IV).
Z
1
Density (calculated),
Mg/mm
1.367
H NMR (CDCl 400 MHz) �: 9.58 (N H),
3
,
3
7
6
J2
.1–7.6 (H(1), H(51) and H(3), H(53)),
.51 (H(2), H(52); dd, J2
Absorption coefficient,
0.254
= 1.8 Hz,
� 1
� 1, 52� 51
mm
F(0 0 0)
= 3.3 Hz), 4.5 (CH O), 7.1–7.6
1088
� 3, 52� 53
2
1
3
Diffractometer used
Bruker SMART/CCD area-detector
˚
(5H). C NMR (CDCl 100 MHz) �: 187.8
3
,
Radiation and wavelength Mo K� with � = 0.71073 A
(
C S), 160.5 (C O), 152.6, 147.2 (C(4), C(54)),
18.2, 115.2 (C(3), C(53)), 112.9, 112.2 (C(2),
C(52)), 145.7, 144.0 (C(1), C(51)), 73.9, 64.9
Scan type
� and ω scans
1
Temperature, K
range for data
collection, deg
293(2)
1.21 to 25.05
�
�
(
(
CH O), 134.4 (1CH), 128.5 (2CH), 127.9
2
Reflections collected
Independent reflections
15730
4489
1
2CH), 141.0 (1C). H NMR (DMSO-d 400
6
,
MHz) �: 12.07 (N H), 8.10, 7.9 (H(1), H(51),
s), 7.75, 7.27 (H(3), H(53); d, J3
= 3.4),
Data/restraints/parameters 4489/0/329
Data-to-parameter ratio
Absolute structure
13.6:1
0.08(10)
� 2, 53� 52
� 1, 52� 51
6
.80, 6.70 (H(2), H(52); dd, J2
= 1.9 Hz,
3
parameter
2
J2
= 3.4 Hz), 5.71, 4.69 (CH O), 7.2–7.6
Goodness-of-fit on F
0.739
� 3, 52� 53
2
1
3
Final R indices [I > 2�(I)] R = 0.0568, wR = 0.0536
1
2
(5H arom.). C NMR (DMSO-d 100 MHz) �:
6
,
R indices (all data)
R1 = 0.1826, wR2 = 0.0744
1
88.8 (C S), 159.8, 154.8 (C O), 148.3, 146.1

O-benzyl-N-(2-furoyl)thiocarbamate
91
Table 2. More Significant Planes and Angles Between Them Obtained Through PLATON
˚
Software With Deviation <0.1 A
Number of plane
Plane determining atoms
1
2
3
4
8
O(1), C(1), C(2), C(3), C(4) (furanic ring)
O(51), C(51), C(52), C(53), C(54) (furanic ring)
C(8), C(9), C(10), C(11), C(12), C(13) (bencenic ring)
C(58), C(59), C(60), C(61), C(62), C(63) (bencenic ring)
S(1), O(3), N(1), C(6), C(7)
1
0
S(2), O(53), N(51), C(55), C(56), C(57)
Planes
Angle (deg)
Planes
Angle (deg)
Planes
Angle (deg)
1
1
2
3
4
–2
–8
–4
–4
–8
55.3(4)
30.3(3)
45.2(4)
29.4(3)
33.9(3)
1–3
1–10
2–8
3–8
4–10
21.6(3)
70.3(3)
76.8(3)
12.7(3)
59.3(3)
1–4
2–3
2–10
3–10
8–10
12.2(3)
74.7(4)
16.6(3)
88.0(3)
87.67(18)
program, and the refinement of the structure per-
Results and discussion
4
formed using the SHELXTL-NT software. The
6
ORTEP-3 software was used to produce molec-
O-benzyl-N-(2-furoyl)thiocarbamate sho-
wed two different structures in the same crystal
sample. The structures of syn (I) and anti (II) con-
formers present an almost planar conformation
throughout the furoylthiocarbamoyl moiety. Both
conformersarehydrogenbondedtoeachotherand
contained in the same asymmetric unit. The asym-
metric unit is shown in Fig. 2. Torsional angles are
listed in Table 3.
ular graphics.
Non-hydrogen atoms were refined anisotrop-
ically. The hydrogen atoms were positioned ge-
ometrically and refined using a “riding-model.”
H(71) was found by Fourier difference and one
overall isotropic thermal parameter was refined.
Atomic coordinates and equivalent isotropic dis-
placement parameters are given in the supplemen-
tary material. The planes, and the angles between
them, are given in Table 2, and were calculated
using the PLATON software.7
The intermolecular hydrogen bonding
between both conformers in the asymmetric unit
is best observed in Fig. 2. The distance between
Table 3. Torsional/Dihedral Angles (deg) for 1
Anti conformer
Syn conformer
C(55) N(51) C(56) S(2)
C(5) N(1) C(6) S(1)
C(5) N(1) C(6) O(3)
C(6) N(1) C(5) O(2)
C(6) N(1) C(5) C(4)
C(6) O(3) C(7) C(8)
C(7) O(3) C(6) N(1)
C(7) O(3) C(6) S(1)
C(9) C(8) C(7) O(3)
C(13) C(8) C(7) O(3)
O(2) C(5) C(4) O(1)
O(2) C(5) C(4) C(3)
N(1) C(5) C(4) C(3)
N(1) C(5) C(4) O(1)
171.2(5)
� 7.6(9)
6.4(9)
� 176.6(5)
12.9(10)
� 166.7(5)
173.9(5)
� 176.6(4)
0.5(7)
123.1(6)
� 59.2(7)
0.5(9)
C(55) N(51) C(56) O(53)
C(56) N(51) C(55) O(52)
C(56) N(51) C(55) C(54)
C(56) O(53) C(57) C(58)
C(57) O(53) C(56) N(51)
C(57) O(53) C(56) S(2)
C(59) C(58) C(57) O(53)
C(63) C(58) C(57) O(53)
O(52) C(55) C(54) O(51)
O(52) C(55) C(54) C(53)
N(51) C(55) C(54) C(53)
N(51) C(55) C(54) O(51)
� 19.5(10)
160.6(5)
� 168.4(6)
178.1(4)
� 0.6(9)
2.3(9)
� 179.2(5)
� 5.5(9)
170.9(6)
� 9.2(10)
174.4(4)
178.2(7)
� 2.3(10)
� 179.9(5)

9
2
Montiel-Ortega, Rojas-Lima, Otazo-Sanchez, and Villag o´ mez-Ibarra
Fig. 2. Conformers I and II of O-benzyl-N-(2-furoyl)thiocarbamate in the same
asymmetric unit, with the atomic numbering scheme. Displacement ellipsoids are
drawn at the 30% probability level.
˚
O(2) and H(71) N(51) is 2.152 (2) A (O(2) ���
is outside the asymmetric unit and has a distance
�
˚
H(71) N(51) = 171.75 ), this value is signifi-
of 2.152 A for N(1) H(21) ���O(52) (N(1)
�
cantly shorter than the sum of the van der Waals
H(21) ���O(52) = 151.16 ) (symmetry code: x,
8
˚
radii of Oxygen and Hydrogen (2.70 A). The
other intermolecular hydrogen bonding observed
y + 1, z) (Fig. 3). These two intermolecular
bonding form a zigzag chain along the b-axis.
Fig. 3. Intermolecular hydrogen bonding inside and outside asymmetric unit along b-axis.

O-benzyl-N-(2-furoyl)thiocarbamate
93
1
The angle between the plane defined
by N(1) C(6)(S(1)) O(3) C(7) (anti conformer)
and the plane defined by N(51) C(56)(S(2))
O(53) C(57) (syn conformer) was 87.67(18) , in-
dicating that both conformers have an orthogonal
position in the asymmetric unit.
The H NMR spectrum of 1 shows a signal at
9
.58 ppm in CDCl , and at 12.07 ppm in DMSO-
d6, which corresponds to an acidic NH (thiocarba-
mate). Similar values are reported for 1-furoyl-3-
benzylthiourea in DMSO-d . Each furan proton
and CH shows two signals on each solvent. The
C NMR spectrum in both solvents shows the
same phenomena, indicating the existence of two
structures in solution in spite of the different prop-
erties of the solvents studied. The C S (at 187.8
and 188.8 ppm) and C O (160.5 and 159.8 ppm)
signals (in CDCl and DMSO-d , respectively) are
3
�
3
6
2
13
The furan ring of one conformer and the aro-
matic ring of the other have a parallel orientation
�
and the angle between those groups was 12.2(3) .
On the other hand, the furan ring of the syn con-
former and the aromatic ring of the anti conformer
have a different orientation and the angle between
3
6
�
these groups is 74.7(4) .
within the expected chemical shifts.
In the anti conformer, the torsional angle of
�
the C(5) N(1) C(6) O(3) moiety is � 7.6 (9)
and the torsional angle of the C(5) N(1) C(6)-
S(1) unit is 171.2(5) . In the syn conformer
Acknowledgments
�
the torsional angle formed between O(53)
C(56) N(51) C(55) and S(2) C(56) N(51)
We are grateful to CONACyT (Project
32718-E)for financial support. AM acknowledges
CONACyT for a MSc fellowship. We are grateful
to Dr. Alejandro Alvarez (UAEH) for the English
review.
�
�
C(55) atoms are � 176.6(5) and 6.4(9) , respec-
tively (Table 3). These last values are almost op-
posite for both conformers. The angle between the
plane defined by the phenyl ring atoms (C(58)
C(59) C(60) C(61) C(62) C(63)), and the
plane defined by the N(51) C(56)(S(2)) O(53)
References
�
C(57) atoms is 59.3(3) in the anti conformer. In
the syn conformer those groups have a different
position and therefore, the angle formed between
them is 12.7(3) .
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3
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Rojas-Lima, S.; Alonso-Chamarro, J. J. Chem. Soc. Perkin Trans.
�
The KBr IR spectrum of 1 displays absorp-
�
1
tions at 1664 cm (C O) and a broad, strong ab-
2001, 2, 2211.
�
1
4. SHELXTL-NT Version 5.1; Bruker Analytical X-Ray Systems:
sorption at 3354 cm (NH). These bands are con-
Madison, USA, 1998.
sistent with hydrogen bonding. In CHCl solution,
3
5. Spek, A.L. Acta Cryst. Sect. C. 1990, A46, 34.
6. SAINT + NT Version 6.01; Bruker Analytical X-ray Systems:
Madison, USA, 1999.
where the free (non H-bonded) form is present,
the signal of both absorptions appear at higher fre-
7. Farrugia, L.J. J. Appl. Cryst. 1997, 30, 565.
�
1
� 1
quencies: 3413 cm (NH) and 1683 cm (C O).
8. Bondi, A. J. Phys. Chem. 1964, 68, 441.