Crystal structure of 2-methyl-4-[(thio­phen-2-yl)methyl­idene]-1,3-oxazol-5(4H)-one

Preetika Sharma; K N Subbulakshmi; B Narayana; K Byrappa; Rajni Kant

doi:10.1107/S2056989015000833

. 2015 Jan 21;71(Pt 2):o123–o124. doi: 10.1107/S2056989015000833

Crystal structure of 2-methyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one

Preetika Sharma ^a, K N Subbulakshmi ^b, B Narayana ^b, K Byrappa ^c, Rajni Kant ^a,^*

PMCID: PMC4384586 PMID: 25878864

Abstract

The asymmetric unit of the title compound, C₉H₇NO₂S, contains two crystallographically independent molecules (A and B). Both molecules are almost planar [maximum deviations = 0.047 (1) and 0.090 (1) Å, respectively, for the S atoms] with the oxazole and thiophene rings being inclined to one another by 2.65 (16)° in molecule A and by 4.55 (15)° in molecule B. In the crystal, the individual molecules are linked via C—H⋯O hydrogen bonds, forming –A–B–A–B– chains along the [10-1] direction. The chains are linked via C—H⋯π and π–π interactions [intercentroid distances = 3.767 (2) and 3.867 (2) Å] involving inversion-related oxazole and thiophene rings in both molecules, forming a three-dimensional structure.

Keywords: crystal structure; azlactones; 1,3-oxazol-5(4H)-one; hydrogen bonding; C—H⋯π and π–π interactions

Related literature

For the different roles of 1,3-oxazol-5(4H)-one derivatives, see: Etschenberg et al. (1980 ▸); Reed & Kingston (1986 ▸). For the crystal structure of 2-(naphthalen-1-yl)-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one, see: Gündoğdu et al. (2011b ▸). For the crystal structures of some oxazole compounds, see: Gündoğdu et al. (2011a ▸); Sun & Cui (2008 ▸); Huang et al. (2012 ▸); Asiri & Ng (2009 ▸).

Experimental

Crystal data

C₉H₇NO₂S
M _r = 193.22
Monoclinic,
a = 12.2264 (11) Å
b = 9.8581 (7) Å
c = 15.8735 (13) Å
β = 112.129 (10)°
V = 1772.3 (2) Å³
Z = 8
Mo Kα radiation
μ = 0.33 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.20 mm

Data collection

Oxford Diffraction Xcalibur Sapphire3 diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010 ▸) T _min = 0.842, T _max = 1.000
7052 measured reflections
3472 independent reflections
2477 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.126
S = 1.04
3472 reflections
237 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.34 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▸); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2015 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S2056989015000833/su5054sup1.cif

e-71-0o123-sup1.cif^{(24.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015000833/su5054Isup2.hkl

e-71-0o123-Isup2.hkl^{(166.8KB, hkl)}

Click here for additional data file.^{(3.5KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015000833/su5054Isup3.cml

Click here for additional data file.^{(1.2MB, tif)}

. DOI: 10.1107/S2056989015000833/su5054fig1.tif

A view of the molecular structure of the two independent molecules of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 40% probability level.

Click here for additional data file.^{(1.8MB, tif)}

b A B . DOI: 10.1107/S2056989015000833/su5054fig2.tif

A view along the b axis of the crystal packing of the title compound. The C—H⋯O ydrogen bonds are shown as dashed lines (see Table 1 for details; molecule A blue; molecule B red).

CCDC reference: 1043723

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

Cg1 is the centroid of the thiophene ring S1A/C1AC4A.

DHA	DH	HA	D A	DHA
C3AH3AO2B ⁱ	0.93	2.56	3.449(3)	161
C3BH3BO2A ⁱⁱ	0.93	2.49	3.336(3)	151
C9BH9B2Cg1ⁱⁱⁱ	0.96	2.96	3.783(4)	145

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

RK acknowledges the Department of Science and Technology for the single-crystal X-ray diffractometer, sanctioned as a National Facility under Project No. SR/S2/CMP-47/2003. KNS gratefully acknowledges the Department of Chemistry and Shri Madhwa Vadiraja Institute of Technology, Bantakal, for providing research facilities.

supplementary crystallographic information

S1. Comment

Erlenmeyer azlactones have been used in a wide variety of reactions as precursors for biologically active peptides (Etschenberg et al., 1980; Reed & Kingston, 1986), herbicides and fungicides, pesticides, agrochemical intermediates and as drugs. The crystal structures of some 1,3-oxazol-5(4H)-one derivative viz., 2-(naphthalen-1-yl)-4-(naphthalen-1-ylmethylidene)-1,3-oxazol-5(4H)-one (Gündoğdu et al., 2011a), 2-phenyl-4-(3,4,5-trimethoxybenzylidene)-1,3-oxazol-5(4H)-one (Sun & Cui, 2008), 4-[(3-methoxyanilino)methylidene]-2-phenyl-1,3-oxazol-5(4H)-one (Huang et al., 2012), (E)-4-(2,5-dimethoxybenzylidene)-2-phenyl-1,3-oxazol-5(4H)-one (Asiri & Ng, 2009) have been reported. In view of the importance of 1,3-oxazol-5(4H)-one, we report herein on the crystal structure of the title compound.

The asymmetric unit of the title compound, Fig. 1, contains two crystallographically independent molecules (A and B), which are almost identical (Fig. 2). The molecular structure is comprised of an oxazole and a thiophene ring which are almost coplanar with a dihedral angle between the rings of 2.65 (16)° in molecule A and 4.55 (15)° in molecule B. All the bond lengths and angles of the title molecule are within normal ranges, and are close to those observed for a very similar structure, viz. 2-(naphthalen-1-yl)-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one (Gündoğdu et al., 2011b).

In the crystal, the individual molecules are linked via C—H···O hydrogen bonds forming -A-B-A-B- chains along direction [101]; Fig. 2 and Table 1. The chains are linked via C-H···π (Table 1) and π-π interactions forming a three dimensional structure [Cg1···Cg2ⁱ = 3.767 (2) A° and Cg3···Cg4ⁱⁱ = 3.886 (2) Å where Cg1, Cg2, Cg3 and Cg4 are the centroids of rings S1A/C1A-C4A, O1A/N1A/C6A-C8A, S1B/C1B-C4B and O1B/N1B/C6B-C8B, respectively, with symmetry codes: (i) -x+1, -y+1, -z and (ii) -x+1, -y+1, -z+1].

S2. Experimental

A mixture of acetyl glycine (2 g, 0.017 mol), thiophene-2-carbaldehyde (1.91 g, 0.017 mol), anhydrous sodium acetate (1.39 g, 0.017 mol) and acetic anhydride (5.20 g, 0.051 mol) was heated on electric plate with constant stirring. As soon as the mixture liquefied completely, the resulting solution was refluxed for 2 h. 25 ml of ethanol was added slowly to the contents of the flask and the mixture was allowed to stand overnight in a refrigerator. The solid mass that separated out was stirred with 60 ml of cold water, filtered, washed with cold water and recrystallized from carbon tetrachloride. Single crystals were grown from chloroform by the slow evaporation method (m.p.: 411-412 K).