Co-crystal structure of mixed molecules of methyl 2-(3-chloro-4-methyl-2- oxo-2H-chromen-7-yloxy)acetate and 2-(2-aminophenyl)benzothiazole

Article abstract of DOI:10.1134/S002247661303030X

A co-crystal is obtained in a methanolic solution from methyl 2-(3-chloro-4-methyl-2-oxo-2H-chromen-7-yloxy)acetate and 2-(2-aminophenyl) benzothiazole. In the crystal these molecules are connected via usual N-H.O and weak C-H.O H-bonds. The co-crystals are very stable.

Full text of DOI:10.1134/S002247661303030X

Journal of Structural Chemistry. Vol. 54, No. 3, pp. 648-649, 2013
Original Russian Text Copyright © 2013 by A. A. Al-Amiery, A. A. Al-Temimi,
A. A. H. Kadhum, Ya. K. Al-Majedy, R. I. Al-Bayati, H. A. Aday, A. B. Mohamad
CO-CRYSTAL STRUCTURE OF MIXED MOLECULES
OF METHYL 2-(3-CHLORO-4-METHYL-2-OXO-2H-CHROMEN-
7-YLOXY)ACETATE AND 2-(2-AMINOPHENYL)BENZOTHIAZOLE
1,2
A. A. Al-Amiery, A. A. Al-Temimi, A. A. H. Kadhum,
2
1
UDC 548.737
2
Ya. K. Al-Majedy, R. I. Al-Bayati, H. A. Aday,
2
2
1
and A. B. Mohamad
A co-crystal is obtained in a methanolic solution from methyl 2-(3-chloro-4-methyl-2-oxo-2H-chromen-7-
yloxy)acetate and 2-(2-aminophenyl)benzothiazole. In the crystal these molecules are connected via usual
N–H…O and weak C–H…O H-bonds. The co-crystals are very stable.
DOI: 10.1134/S002247661303030X
Keywords: 2-(2-aminophenyl)benzothiazole, co-crystal, coumarins, methanol, single crystal X-ray.
Drug resistance has become a growing problem in the treatment of infectious diseases caused by bacteria and fungi
[1, 2]. Coumarin and its derivatives represent one of the most active classes of compounds possessing a wide spectrum of
biological activity [3-7]. Structure activity relationships of coumarin derivatives have revealed that the presence of substituted
amino derivatives is an essential feature of their pharmacological action. Based on these findings, we tried to describe the
synthesis of some compounds featuring different heterocyclic rings fused onto the coumarin moiety with the aim of obtaining
more potent pharmacologically active compounds, but the reaction did not occur.
Experimental. The chemicals used during the synthesis were supplied by Sigma-Aldrich. Purity of the compounds
was checked on thin layer chromatography (TLC) plates (Silica gel G) in benzene: ethyl acetate : methanol (40:30:30, v/v/v)
and toluene : acetone (75:25, v/v) solvent systems. The spots were located under UV light 254 nm and 365 nm.
General procedure for the synthesis of the co-crystal. A mixture of 0.05 mol of 2-(2-aminophenyl)benzothiazole
and 0.05 mol of methyl 2-(3-chloro-4-methyl-2-oxo-2H-chromen-7-yloxy)acetate in methanol was refluxed for 2 h; a suitable
co-crystal was obtained by evaporation of the methanol solution.
Crystal structure determination. Diffraction data were collected on a Bruker APEX CCD area-detector
diffractometer at 298(2) K on a crystal with dimensions 0.50×0.33×0.26 mm (MoK radiation, wavelength 0.71073 Å).
α
Empirical formula C H ClN O S; formula weight 508.96, monoclinic, space group P2 /n, unit cell dimensions
26 21 2 5 1
3 3
a = 12.611(2) Å, b = 7.3544(13) Å, c = 25.980(5) Å, β = 99.031(4)°, V = 2379.7(7) Å , Z = 4. Calculated density = 1.421 g/cm .
–1
Absorption coefficient = 0.290 mm . F(000) = 1056. θ range for data collection 1.59° to 25.50°. Limiting indices
–15 ≤ h ≤ 15, –8 ≤ k ≤ 8, –31 ≤ l ≤ 23. Reflections collected/unique 13480/4416 [R(int) = 0.0263]. Completeness to θ =
2
25.50° 99.8%. Max. and min. transmission 0.9285 and 0.8687. Refinement method: full-matrix least-squares on F .
2
Data/restraints/parameters 4416/0/321. GOOF on F 1.033. R indices (all data) R = 0.0679, wR = 0.1435. Largest diff. peak
1
2
3 3
and hole 0.524 e/Å and –0.411 e/Å .
1
Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti of
2
Kebangsaan Malaysia, Bangi, Selangor, 43600, Malaysia; dr.ahmed1975@gmail.com. Chemistry Division, Applied Science
Department, University of Technology, Baghdad, Iraq. The text was submitted by the authors in English. Zhurnal Strukturnoi
Khimii, Vol. 54, No. 3, pp. 593-594, May-June, 2013. Original article submitted February 24, 2012.
648
0022-4766/13/5403-0648 © 2013 Springer Science+Business Media, Inc.

Fig. 1. Crystal structure of the co-crystal.
Results and discussion. From the crystal structure (Fig. 1) it was found that there were two molecules in the crystal
structure; the first was methyl 2-(3-chloro-4-methyl-2-oxo-2H-chromen-7-yloxy)acetate and the second 2-(2-aminophenyl)×
benzothiazole). As shown in Fig. 1, there are hydrogen bonds between methyl 2-(3-chloro-4-methyl-2-oxo-2H-chromen-7-
yloxy)acetate and 2-(2-aminophenyl) benzothiazole: N(2)–H…O(4) (H…O distance 2.22(3) Å, N–H…O angle 175(3)°) and
weak C(15)–H…O(2) (H…O 2.51 Å, C–H…O 146°).
2-(2-Aminophenyl)benzothiazole. The benzothiazole group is not coplanar with the aryl ring; this is attributed to a
steric interaction of the aryl group and the amino group with benzothiazole nitrogen. In addition, the C(20)–C(21) bond
length is 1.461 Å and the C(22)–C(21)–C(20) bond angle is 119.7° and C(26)–C(21)–C(20) is 121.4°. Moreover, the С(26)–
С(21)–С(20)–N(1) torsion angle is 12.7°.
2-(3-Chloro-4-methyl-2-oxo-2H-chromen-7-yloxy)acetate (coumarin derivative). From Fig. 1 it is clear that the
coumarin molecule is flatter, but there is a steric interaction of the extension of the acetyl group at O(3). The bond lengths of
O(3)–C(8) is 1.364 Å and O(3)–C(11) is 1.414 Å, and the bond angles for O(3)–C(8)–C(7) is 114.9°, O(3)–C(8)–C(9) 125.0°,
and C(8)–O(3)–C(11) 117.8(2)°. Moreover, the C(8)–O(3)–C(11)–C(12) torsion angle is –178.4°, C(11)–O(3)–C(8)–C(7) is
175.6°, and О(3)–С(11)–С(12)–О(4) is 16.3°.
Conclusions. In this study, the coumarin derivative has been unsuccessfully synthesized. The structure of a stale
shiny light brown crystal was determined by X-ray single crystallography and the hydrogen bonding N–H…O and C–H…O
was found between the molecules of methyl 2-(2-oxo-2H-chromen-7-yloxy)acetate and 2-(2-aminophenyl)benzothiazole).
The bond lengths and bond angles are very close to the corresponding ones found in the Cambridge structural database (ethyl
(4-methyl-7-coumarinyloxy)acetate [8], 2-(o-hydroxyphenyl)-1,3-benzothiazol [9] for example).
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