Browsing by Author "Islor, A.M."

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1-[5-Acetyl-2,6-dimethyl-4-(5-phenyl-1H-pyrazol-3-yl)-1, 4-dihydropyridin-3-yl]ethanone monohydrate
(2012) Islor, A.M.; Malladi, S.; Sundershan, S.; Gerber, T.; Hosten, E.; Betz, R.
In the title compound, C20H21N3O 2·H2O, the aza-substitued six-membered ring adopts a L4 B conformation. In the crystal, classical N-H?O, N-H?N and O-H?O hydrogen bonds connect the entities into a three-dimensional network. Intramolecular C-H?O contacts are also observed.
3-(4-Chlorophenyl)-5-phenyl-4,5-dihydro-1,3-oxazole
(2012) Islor, A.M.; Yaradoni, R.; Garudachari, B.; Gerber, T.; Hosten, E.; Betz, R.
In the title compound, C15H12ClNO, the isoxazoline ring adopts an envelope conformation with the C atom bearing an unsubstituted phenyl ring as the flap atom. The chlorinated phenyl group is nearly in-plane with the four coplanar atoms of the heterocycle and the corresponding mean planes enclosing an angle of 1.16(7)°. The unsubstituted phenyl group attached to the envelope flap atom approaches a nearly perpendicular orientation relative to the isoxazoline ring with a dihedral angle of 74.93(7)°. In the crystal, weak C-H?O, C-H?N and C-H?? interactions connect the molecules into layers perpendicular to the a axis.
Crystal structure of ethyl 6-methyl-4-oxo-1,4-dihydroquinoline-3- carboxylate, C13H13NO3
(2013) Garudachari, B.; Islor, A.M.; Satyanarayan, M.N.; Gerber, T.; Hosten, E.; Betz, R.
(Equation presentation)(Table presentation) Source of material Diethyl{[(4-methylphenyl)amino]methylidene}propanedioate (1.0 g, 0.003 mol) and Dowtherm (10 mL) were heated to 250 °C for 5 h. The reactionmixture was then cooled to 25 °C and stirred in n-hexane (10 mL) for 10 min. The solid product obtained was filtered, dried and recrystallized from ethanol. Single crystals suitable for the X-ray diffraction study were grown by slow evaporation of a diluted ethanol solution of the compound at room temperature, yield: 0.79 g (95.1 %) [8]. Discussion Heterocyclic derivatives attract the interest ofmedicinal chemists because of their varied biological activities such as their anti-microbial [1] or analgesic [2] properties. Particularily intriguing are quinoline and its derivatives as these have already found application as anticancer [3], antiviral [4] and antimalarial [5] agents. In view of the biological importance as well as possible pharmacological applications, the title compound was synthesized to study its crystal structure. Although the title compound could be present in an aromatic form spanning the whole core of themolecule (i.e. as ethyl 4-hydroxy-6-methylquinoline-3-carboxylate), a tautomer featuring only an aromatic system on the non-heterocyclic ring is observed in the solid state. The least-squares planes defined by the respective intracyclic atoms of each of the two sixmembered rings enclose an angle of just 1.41(11)°. The leastsquares plane defined by all non-hydrogen atoms of the aza-naphthalene core is essentially flat (r.m.s. of all fitted atoms = 0.015 Å) with the carbon atom bearing the ester substituent deviatingmost from the plane (by 0.026(2) Å). The hydrogen atom of the secondary amine group forms a hydrogen bond to the two doublebonded oxygen atom of the ester group. In terms of graph-set analysis [6, 7], the descriptor for the N-H Otype hydrogen bond necessitates a C1 1(6). In total, the molecules are connected to chains along the b direction. (Table presentation).
Diethyl 2,6-dimethyl-4-[5-(4-methylphenyl)-1H-pyrazol-4-yl]-1,4- dihydropyridine-3,5-dicarboxylate
(2012) Islor, A.M.; Malladi, S.; Telkar, S.; Gerber, T.; Hosten, E.; Betz, R.
In the title compound, C23H27N3O4, the dihydropyridine ring adopts a 1,4 B conformation. Intramolecular C-H?O contacts occur. In the crystal, N-H?O and N-H?N hydrogen bonds and C-H?N contacts connect the molecules into strands along the a-axis direction.
Dimethyl 2,6-dimethyl-4-{3-[4-(methylsulfanyl)phenyl]-1H-pyrazol-4-yl}-1,4- dihydropyridine-3,5-dicarboxylate monohydrate
(2012) Islor, A.M.; Vijesh, A.M.; Gerber, T.; Hosten, E.; Betz, R.
In the title compound, C21H23N3O4S·H2O, the methylsulfanyl group is disordered over two sets of sites with site-occupancy factors of 0.631 (11) and 0.369 (11). The dihydropyridine ring adopts an E 4 conformation. In the crystal, classical O-H?N, O-H?O and N-H?O hydrogen bonds, as well as C-H?O and C-H?S contacts, connect the molecules into a three-dimensional network.
Ethyl (Z)-3-(4-methylanilino)-2-[(4-methylphenyl)carbamoyl]prop-2-enoate
(2012) Islor, A.M.; Garudachari, B.; Gerber, T.; Hosten, E.; Betz, R.
The title compound, C20H22N2O3, is a secondary amine featuring an amide and an ester functionality in connection with a Michael system. The conformation about the C=C bond is E. Intramolecular N-H?O hydrogen bonds occur. In the crystal, C-H?O contacts connect the molecules into chains along the b-axis direction.
Ethyl 3-(2-ethoxy-2-oxoethoxy)-6-(trifluoromethyl)furo[3,2-c]quinoline-2- carboxylate
(2012) Garudachari, B.; Islor, A.M.; Vijesh, A.M.; Gerber, T.; Hosten, E.; Betz, R.
In the title compound, C19H16F3NO6, a quinoline derivative featuring an annealated furan substituent, the mean planes of the carboxy substituents are at an angle of 74.3 (2)°. In the crystal, C-H?O contacts result in undulating chains along [110]. C-H?F contacts also occur. The shortest centroid-centroid distance between rings is 3.3376 (7) Å, involving two furan rings of neighbouring molecules.
Ethyl 4-({1-[2-(4-bromophenyl)-2-oxoethyl]-1H-1,2,3-triazol-4-yl}methoxy)- 8-(trifluoromethyl)quinoline-3-carboxylate
(2012) Islor, A.M.; Garudachari, B.; Shivananda, K.N.; Gerber, T.; Hosten, E.; Betz, R.
The title compound, C24H18BrF3N4O4, is a 1,2,3-triazole derivative featuring, among others, a quinoline-derived substituent. In the crystal, C-H?O, C-H?N and C-H?F contacts connect the molecules into a three-dimensional network. The shortest centroid-centroid distance between two aromatic systems is 3.896 (2) Å and is found between the two different six-membered rings of the quinoline scaffold in neighbouring molecules.
Ethyl 4-oxo-8-trifluoromethyl-1,4-dihydroquinoline-3-carboxylate
(2012) Garudachari, B.; Islor, A.M.; Satyanarayan, M.N.; Gerber, T.; Hosten, E.; Betz, R.
The asymmetric unit of the title compound, C13H10F3NO3, contains two independent molecules with similar conformations. In the crystal, N-H?O hydrogen bonds link alternating independent molecules into chains in [-110]. In the chain, the quinoline planes of the independent molecules are almost perpendicular to each other, forming a dihedral angle of 89.8 (1)°. ?-? interactions between the aromatic rings of quinoline bicycles related by inversion centres [for two independent centrosymmetric dimers, the shortest centroid-centroid distances are 3.495 (1) and 3.603 (1) Å] link the hydrogen-bonded chains into layers parallel to (110). Weak C-H?F and C-H?O interactions further consolidate the crystal packing.
Quinolin-3-amine
(2012) Islor, A.M.; Chandrakantha, B.; Shetty, P.; Gerber, T.; Hosten, E.; Betz, R.
In the crystal structur of the achiral title compound, C9H 8N2, N-H?N hydrogen bonds connect the molecules into zigzag chains in [100]. Weak intermolecular N-H?? interactions further consolidate the crystal packing.
Redetermination of the structure of 1,4-diethoxybenzene, C 10H14O2
(2013) Islor, A.M.; Garudachari, B.; Gerber, T.; Hosten, E.; Betz, R.
C10H14O2, monoclinic, P21 (no. 4), a = 7.0647(2) Å, b = 7.4686(3) Å, c = 9.4212(3) Å, ? = 110.615(2)°, V = 465.3 Å3, Z = 2, Rgt(F) = 0.0332, wRref(F2) = 0.0898, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.
Redetermination of the structure of 4-amino-benzonitrile, C 7H6N2
(2013) Islor, A.M.; Chandrakantha, B.; Gerber, T.; Hosten, E.; Betz, R.
C7H6N2, monoclinic, P21/c (no. 14), a = 7.2382(6) Å, b = 5.4770(4) Å, c = 16.040(2) Å, ? = 101.680(4)°, V = 622.7 Å3, Z = 4, Rgt(F) = 0.0500, wRref(F2) = 0.1377, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.
Redetermination of the structure of anthracen-9-yl-methanol, C 15H12O
(2013) Islor, A.M.; Somashekara, B.; Garudachari, B.; Gerber, T.; Hosten, E.; Betz, R.
(Equation presentation) (Table presentation) Source of material The title compound was synthesized according to the literature [4]. Experimental details Carbon-bound hydrogen atoms were placed in calculated positions (C-H 0.95 Å for aromatic carbon atoms and C-H 0.99 Å for methylene groups) and were included in the refinement in the ridingmodel approximation, withU iso(H) set to 1.2Ueq(C). TheHatoms of the hydroxyl groups were allowed to rotate with a fixed angle around the C-O bond to best fit the experimental electron density (HFIX 147 in the SHELXprogram suite [5]), withUiso(H) set to 1.5Ueq(C). Due to the absence of a strong anomalous scatterer, the Flack-X parameter is meaningless. Thus, Friedel opposites (1703 pairs) have been merged and the item was removed from the CIF. Discussion Anthracene is a key substance in the production of anthraquinone as well a various dyes, pigments, insecticides, wood preservatives and coatingmaterials. As several anthracene derivatives exhibit light and temperature sensitivity, heat resistance, conductivity, emittability, and corrosion resistance, they have been a focus of chemical research. Due to ?-electron cloud overlaps, anthracene itself exhibits semiconductor properties [1]. Organic semiconductors are interesting due to their abilities of self radiation next to their flexibility, light weight, easy fabrication and low cost. They have been investigated as organic electroluminescence materials for application in organic solar cells, biosensitizers and display devices such as organic light-emitting diodes (OLEDs) [2]. The structure of the title compound at room temperature has been determined earlier during an investigation about triboluminescence effects and the discussion of structural features in this manuscript is scant [3]. The asymmetric unit features two crystallographic independant molecules of the title compound. The aromatic scaffold of both molecules is essentailly flat (r.m.s. of all fitted non-hydrogen atoms = 0.0167 Å and 0.0175 Å, respectively). The least-squares planes defined by the carbon atoms of the "outer" phenyl rings intersect at angles of 1.7(1)° and 1.8(1)°, respectively, in both molecules. The two molecules are not stacked parallel or perpendicular with respect to each other, the aromatic moieties of both molecules enclose an angle of 54.48(5)°. In bothmolecules, the hydroxy-methyl group is orientated approximately perpendicular to the aromatic system, the respective O-C-C-C dihedral angles are measured at -77.8(2)° and 77.9(2)°. The crystal structure is characterized by hydrogen bonds by the hydroxyl groups. These connect the two molecules present in the asymmetric unit intermittently to chains along the crystallographic b axis. (Table presentation).