organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
configuration at atom C22. Compounds (II)–(VI) all crystal-
lize with Z0 = 1, either in the space group C2/c [(V)], or in
space groups P21/c or P21/n [(II)–(IV) and (VI)], but the cell
dimensions of (I) bear no close resemblance to those in any of
(II)–(VI).
ISSN 0108-2701
3-Benzyl-2-(4-fluorophenyl)-1,3-thia-
zolidin-4-one
a
b
c
´
Alexander Gutierrez, Braulio Insuasty, Justo Cobo and
Christopher Glidewelld*
a
´
´
Ciudadela Universitaria, Universidad Tecnologica del Choco, AA 292 Quibdo,
b
´
Colombia, Departamento de Quımica, Universidad de Valle, AA 25360 Cali,
c
´
´
´
´
Colombia, Departamento de Quımica Inorganica y Organica, Universidad de Jaen,
23071 Jaen, Spain, and dSchool of Chemistry, University of St Andrews, Fife
´
KY16 9ST, Scotland
Correspondence e-mail: cg@st-andrews.ac.uk
Received 23 September 2010
Accepted 31 October 2010
Online 8 December 2010
The title compound, C16H14FNOS, crystallizes with Z0 = 2 in
the space group P21/c. In one of the two independent
molecules, the heterocyclic ring is effectively planar, but in
the other molecule this ring adopts an envelope conformation.
The molecules are weakly linked by two C—Hꢀ ꢀ ꢀO hydrogen
bonds to form C22(14) chains. Comparisons are made with
some symmetrically substituted 2-aryl-3-benzyl-1,3-thiazoli-
din-4-ones.
In molecule 1 of (I), the heterocyclic ring is effectively
planar, with a maximum deviation from the mean plane
˚
through the ring atoms of only 0.021 (3) A for atom C15.
However, the corresponding ring in molecule 2 adopts an
envelope conformation, folded across the line C22ꢀ ꢀ ꢀC25, with
ring-puckering parameters (Cremer & Pople, 1975) for the
atom sequence S21—C22—N23—C24—C25 of Q2
=
Comment
ꢁ
˚
0.220 (3) A and ’2 = 184.4 (8) . Similar envelope conforma-
tions were observed in each of (III)–(VI), but in (II) the
heterocyclic ring adopts a half-chair conformation, twisted
about the S1—C5 bond (Cunico et al., 2007). It seems likely
that the saturated heterocyclic rings in (I)–(VI) are all fairly
flexible and that their detailed conformations may, to some
extent, be a reflection of direction-specific intermolecular
forces.
In our synthetic search for new bioactive compounds, we have
recently focused on the preparation of thiazol-4-one deriva-
tives, which have shown a wide range of pharmacological
activities (Insuasty et al., 2010, and references therein), i.e.
antibacterial, antifungal, antimicrobial, antiviral and anti-
convulsant activity. We report here the structure of the title
compound, (I) (Fig. 1), an asymmetrically substituted 2-aryl-3-
benzyl-1,3-thiazolidin-4-one derivative, which we compare
with the series of symmetrically substituted analogues (Cunico
et al., 2007), compounds (II)–(VI) (see Scheme). Compound
(I) was prepared in excellent yield using a three-component
cyclocondensation reaction between benzylamine, 4-fluoro-
benzaldehyde and mercaptoacetic acid. By contrast, com-
pounds (II)–(VI) were all prepared using the reactions of aryl
aldehydes with l-valine [(S)-2-amino-3-methylpropionic acid]
and mercaptoacetic acid (Cunico et al., 2006). In all of (I)–
(VI), atom C2 in the heterocyclic ring is a stereogenic centre,
but all of the compounds are formed as racemic mixtures,
despite the presence of an enantiomerically pure amino acid in
the synthesis of (II)–(VI).
The molecules of (I) are weakly linked into chains by two
C—Hꢀ ꢀ ꢀO hydrogen bonds (Table 1), but C—Hꢀ ꢀ ꢀꢀ(arene)
hydrogen bonds and aromatic ꢀ–ꢀ stacking interactions are
absent, despite the presence of four independent and rela-
tively unencumbered aryl rings in the asymmetric unit. Within
the selected asymmetric unit, the two molecules are linked by
a hydrogen bond having atom O14 as the acceptor, and
dimeric units of this type, related to one another by transla-
tion, are linked by a second hydrogen bond having atom O24
as the acceptor, so giving rise to a C22(14) (Bernstein et al.,
1995) chain running parallel to the [100] direction (Fig. 2).
There is a reasonably short C—Hꢀ ꢀ ꢀF contact in (I) invol-
ving atom F124, but no corresponding contact occurs involving
atom F224. However, this contact should not be regarded
neither as a hydrogen bond nor indeed as structurally signif-
icant, as it has been established that halogen atoms bonded to
C atoms are extremely poor acceptors, even from O—H or
Compound (I) crystallizes with Z0 = 2 in the space group
P21/c, and in the selected asymmetric unit, molecule 1,
containing atom S11 (Fig. 1), has the R configuration at atom
C12, while molecule 2, containing atom S21, has the S
o10 # 2011 International Union of Crystallography
doi:10.1107/S0108270110044550
Acta Cryst. (2011). C67, o10–o12