Showing papers by "Badiadka Narayana published in 2013"

A study on the reactions of alkyl 4,6-bis(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate and in vitro antioxidant activity of derivatives

Abstract: New functionalized derivatives were prepared using alkyl 4,6-bis(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate as a building block. Newly prepared compounds were well characterized using 1H NMR, IR, and mass spectral data. All the synthesized products were screened for their antioxidant properties. Among the tested compounds, indazole derivatives exhibited noticeable DPPH radical scavenging activity and reducing power capacity in comparison with the standard Glutathione.

Synthesis and crystal structures of N-substituted pyrazolines.

Abstract: Four pyrazole compounds, 3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde (1), 5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-carbaldehyde (2), 1-[5-(4-chlorophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone (3) and 1-[3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]propan-1-one (4), have been prepared by condensing chalcones with hydrazine hydrate in the presence of aliphatic acids, namely formic acid, acetic acid and propionic acid. The structures were characterized by X-ray single crystal structure determination. The dihedral angles formed between the pyrazole and the fluoro-substituted rings are 4.64(7)° in 1, 5.3(4)° in 2 and 4.89(6)° in 3. In 4, the corresponding angles for molecules A and molecules B are 10.53(10)° and 9.78(10)°, respectively.

2-(2,4-Dichloro-phen-yl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide.

Abstract: In the crystal structure of the title compound, C19H17Cl2N3O2, the mol­ecules form dimers of the R22(10) type through N—H⋯O hydrogen bonding. As a result of steric repulsion, the amide group is rotated with respect to both the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 80.70 (13) and 64.82 (12)°, respectively. The dihedral angle between the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings is 48.45 (5)° while that between the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings is 56.33 (6)°.

2-(2,6-Dichloro-phen-yl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide.

Abstract: In the title compound, C19H17Cl2N3O2, the amide group is planar and, through N—H⋯O hydrogen bonding to an adjoining mol­ecule, forms dimers of the R22(10) type. As a result of steric repulsion, the amide group is rotated with respect to both the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 71.63 (11) and 57.93 (10)°, respectively. The dihedral angle between the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings is 76.60 (10)° while that between the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings is 49.29 (7)°. The crystal structure also features weak C—H⋯O inter­actions.

Pseudosymmetry, polymorphism and weak interactions: 4,4′′-difluoro-5′-hydroxy-1,1′:3′,1′′-terphenyl-4′-carboxylic acid and its derivatives

Abstract: The crystal structures of three derivatives of 4,4′′-difluoro-5′-hydroxy-1,1′:3′,1′′-terphenyl-4′-carboxylic acid are discussed. The acid itself (1), its ethyl ester (2)and hydrazide (3) have been chosen to study the influence of the hydrogen bonding potential on the crystal packing. In 1 and 2 short intramolecular O–H⋯O hydrogen bonds between the hydroxyl and carbonyl groups engage the strong hydrogen bond donors and acceptors, and both these compounds show the effects of packing conflicts. In 1 almost centrosymmetric, stable hydrogen-bonded dimers form between symmetry independent molecules, but the crystal structure is non-centrosymmetric and contains altogether four symmetry-independent molecules (two independent dimers), which show different pseudo-symmetries. In 2 dimer formation is impossible but two different crystal forms of this compound have been found. Both polymorphs crystallize in the P space group and differ mainly in the orientation of the OEt group. In turn in 3 there are no intramolecular hydrogen bonds and the crystal structure is determined mainly by the open motifs created by classical hydrogen bonds and by the complementarity of the respective hydrophilic and hydrophobic parts of the molecule.

Radioprotective effect of an edaravone analogue 3-methyl-1- (4-(trifluoromethyl)phenyl)-1,2-dihydropyrazol-5-one

Abstract: 1 Department of Chemistry, P.A. College of Engineering, Nadupadavu, Mangalore 574 153, Karnataka, India. 2 Industrial Chemistry Division, Department of Chemistry, Mangalore University, Mangalagangotri-Mangalore-574199, Karnataka, India. 3 Department of Chemistry, Mangalore University, Mangalagangotri-574199, Mangalore-574199, Karnataka, India. 4 Microtrone Centre, Department of Physics, Mangalore University, Mangalagangotri, Mangalore – 574199.

4-(4-Iodo­anilino)-2-methyl­ene-4-oxo­butanoic acid

Abstract: In the title compound, C11H10INO3, an addition product of itaconic acid anhydride and 4-iodo­aniline, the least-squares planes defined by the atoms of the aromatic moiety and the non-H atoms of the carb­oxy­lic acid group enclose an angle of 7482 (11)° In the crystal, classical O—H⋯O hydrogen bonds formed by carb­oxy­lic groups, as well as N—H⋯O hydrogen bonds formed by amide groups, are present along with C—H⋯O contacts Together, these connect the mol­ecules into dimeric chains along the b-axis direction

(2E)-1-(4-Chloro-phen-yl)-3-(4-nitro-phen-yl)prop-2-en-1-one.

Abstract: In the title compound, C15H10ClNO3, a substituted chalcone, the dihedral angle between the benzene rings is 5.1 (7)°. The nitro group makes a dihedral angle of 12.5 (3)° with the benzene ring to which it is attached. In the crystal, weak C—H⋯O inter­actions link the mol­ecules into a one-dimensional array along [010]. The crystal studied was an inversion twin, with a refined ratio for the twin components of 0.6060 (9):0.3939 (1).

Sensitive Spectrophotometric Determinations of Paracetamol and Protriptyline HCl Using 3-Chloro-7-hydroxy-4-methyl-2H-chromen-2-one

Abstract: A new spectrophotometric method is developed for the determination of Paracetamol (PCT) and protriptyline HCl (PTP) in pure forms and in pharmaceutical formulations. The experiment involves the use of 3-chloro-7-hydroxy-4-methyl-2H-chromen-2-one as a novel chromogenic reagent for the determination of PCT and PTP. The method is based on the formation of charge transfer complex between the drugs and chromogenic reagent. Beer's law is obeyed in the concentration ranges 10.00–60.00 µg mL−1 for PCT at 545 nm and 40.00–160.00 µg mL−1 for PTP at 468 nm. The molar absorptivity, Sandell, sensitivity, and limit of detection and quantification are also calculated. The method has been successfully applied for the determination of both PCT and PTP in pharmaceutical samples with acceptable results.

4-[Bis(4-fluoro-phen-yl)meth-yl]-1-[(2E)-3-phenyl-prop-2-en-1-yl]piperazin-1-ium 3-carb-oxy-propano-ate.

Abstract: In the title salt, C26H27F2N2+·C4H5O4−, the piperazine N atom bearing the vinylic substituent is protonated. The piperazine ring adopts a chair conformation. In ther crystal, the succinate monoanions are connected via short O—H⋯O hydrogen bonds between the carb­oxy­lic acid and carboxyl­ate groups into undulating chains extending along [001] and the flunarizinium monocations are attached to these chains via N+—H⋯O− hydrogen bonds. C—H⋯O inter­actions connect these chains into a three-dimensional network. The shortest centroid–centroid distance of 3.7256 (10) A was found between one of the fluorinated benzene rings and the non-fluorinated phenyl ring in the neighbouring mol­ecule related by a glide plane.

N-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-di-hydro-1H-pyrazol-4-yl)-2-phenyl-acetamide.

Abstract: The title compound, C19H19N3O2, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit In mol­ecule A, the pyrazole ring adopts a slightly disordered half-chair conformation while in B it is planar [rms deviation = 00386 (15) A] The dihedral angle between the mean planes of the two phenyl rings is 562 (8) in A and 382 (3)° in B The N-phenyl substituent on the pyrazole ring is twisted by 465 (2) in A and 586 (4)° in B while the extended phenyl ring is twisted by 822 (8) in A and 875 (9)° in B The mean plane of the amide group forms an angle of 748 (3) in A and 677 (1)° in B with respect to the phenyl ring In addition, the amide group is rotated by 514 (1) in A and 536 (2)° in B from the the mean plane of the pyrazole ring In the crystal, the two molecules are linked via N—H⋯O hydrogen bonds, supported by weak C—H⋯O inter­actions, forming dimers enclosing an R22(10) ring motif The dimers are linked via C—H⋯O inter­actions, forming a three-dimensional structure

2-(4-Bromo-phen-yl)-N-(pyrazin-2-yl)acetamide.

Abstract: In the title compound, C12H10BrN3O, the dihedral angle between the mean planes of the 4-bromo­phenyl and pyrazin-2-yl rings is 54.6 (3)°. An intra­molecular C—H⋯O hydrogen bond generates an S(6) graph-set motif. In the crystal, weak N—H⋯N hydrogen bonds link the mol­ecules into chains along [100]. The chains are linked via C—H⋯N and C—H⋯O hydrogen bonds, forming two-dimensional networks lying parallel to the ab plane.

Ethyl 6-(4-chlorophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate

Abstract: Department of Studies in Chemistry, Mangalore University, Mangalagangotri 574 199, India, Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India, Department of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA, and Department of Chemistry, Howard University, 525 College Street NW, Washington, DC 20059, USA Correspondence e-mail: jjasinski@keene.edu

3-Chloro-4-fluoro­anilinium picrate

Abstract: In the title picrate salt of a dihalogenated aniline derivative, C6H6ClF+·C6H2N3O7−, the intra­cyclic C—C—C angles in the picrate anion cover a broad range [111.95 (12)–125.38 (13)°], while those in the aromatic cation span a much narrower range [118.25 (14)–122.33 (13)°]. In the crystal, classical N—H⋯O hydrogen bonds, as well as C—H⋯O contacts, connect the ions into layers parallel to (001).

2-(3,4-Dichloro-phen-yl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide.

Abstract: In the title compound, C19H17Cl2N3O2, there are three mol­ecules (A, B and C) in the asymmetric unit and each differs in the conformation adopted. As a result of steric repulsion, the amide group is rotated with respect to both the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 44.5 (2) and 56.2 (2)°, respectively in A, 51.1 (2) and 54.1 (2)° in B, and 53.8 (2) and 54.6 (2)° in C. The dihedral angles between the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings are 54.8 (2), 76.2 (2) and 77.5 (2)° in mol­ecules A, B and C, respectively, while the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings make dihedral angles of 45.3 (2), 51.2 (2) and 42.8 (2)°, respectively. In the crystal, two of the mol­ecules are linked through N—H⋯O hydrogen bonding to an adjoining mol­ecule, forming dimers of the R22(10) type, while the third mol­ecule forms such dimers with itself. C—H⋯O inter­actions link the dimers.

Synthesis and Crystal Structures of Four New Dihydropyridine Derivatives

Abstract: Four new Hantzsch 1,4-dihydropyridine derivatives, dimethyl 4-(4-hydroxy-3-methoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, (I), dimethyl 4-(4-bromophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, (II), dimethyl 4-(3-bromo-4-methoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, (III), and dimethyl 2-(2,5-dimethoxyphenyl)-4,6-dimethyl-1,2-dihydropyridine-3,5-dicarboxylate, (IV), have been synthesized and examined by X-ray crystallography, B3LYP/6-31 G (d) molecular orbital calculations and Hirshfeld surface and fingerprint plots. (I), C18H20NO6, is monoclinic with space group P21/n and cell constants a = 9.60810(10) A, b = 7.41900(10) A, c = 24.1821(3) A, = 94.1970(10)°, V = 1719.14(4) A3, and Z = 4. (II), C17H15BrN2O6, is orthorhombic with space group P212121 and cell constants a = 11.8865(5) A, b = 13.1157(4) A, c = 21.9515(9) A, V = 3422.2(2) A3, and Z = 8. (III), C18H20BrNO5, is orthorhombic with space group Pbca and cell constants a = 8.55470(10) A, b = 15.5248(2) A, 27.0657(5) A, V = 3594.60(9) A3, and Z = 8. (IV), C19H23NO6, is orthorhombic with space group Pbca and cell constants a = 11.6798(3) A, b = 13.6319(3) A, 23.0976(5) A, V = 3677.55(15) A3, and Z = 8. The first three have the same 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate skeleton with different substituted phenyl ligands attached to the 4-site of the dihydropyridine ring. The fourth derivative (IV) consists of a related 4,6-dimethyl-1,2-dihydropyridine-3,5-dicarboxylate skeleton with 2,5-dimethoxyphenyl and methyl ligands attached to the 2 and 4 sites of the 1,2-dihydropyridine ring. The dihedral angle between the mean planes of the dihydropyridine and benzene rings is 89.6(2)° (I), 86.0(6)° or 87.2(9)° (II), 87.7(6)° (III), and 87.3(8)° (IV), respectively. O–H··· (I), N–H···O (II), N–H···O (IV) hydrogen bonds and weak N–H···O, C–H···O (I), C–H···O (II), N–H···O (III), C–H···O (IV) intermolecular hydrogen bond interactions help stabilize crystal packing in each of their unit cells. A comparison of the angles between mean planes of the benzene rings in the crystals and with the DFT theoretical calculation as well as inclusion of weak intermolecular hydrogen bond interactions has been included for each molecule. Hirshfeld surface analysis for visually analyzing intermolecular interactions in crystal structures employing 3D molecular surface contours and 2D fingerprint plots have also been used to examine molecular shapes. Molecular orbital diagrams provide visual representations of the top level molecular orbital surfaces in each compound. Synthesis, crystal structures, density functional theory (DFT), Hirshfeld and molecular orbital surface calculations of four new dihydropyridine derivitives.

4-(3-Fluoro-4-methyl-anilino)-2-methyl-idene-4-oxo-butanoic acid.

Abstract: The title compound, C12H12FNO3, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. The dihedral angle between the mean planes of the 3-fluoro-4-methyl­phenyl ring and the oxo­amine group is 25.7 (7)° in mol­ecule A and 71.3 (7)° in mol­ecule B, while the mean plane of the 2-methyl­idene-4-oxo­butanoic acid group is twisted by 76.2 (1)° from that of the oxo­amine group in mol­ecule A and by 76.2 (4)° in mol­ecule B. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds [the latter forming an R22(8) graph-set motif] link the mol­ecules into a two-dimensional network parallel to the ac plane.

(E)-N'-(4-Fluoro-benzyl-idene)-2-(3-methyl-phen-yl)acetohydrazide.

Abstract: In the title compound, C16H15FN2O, the dihedral angles between the benzene rings are74.7(8), 74.1 (1), 74.2 (7) and 74.3 (5)° in the four independent mol­ecules in the asymmetric unit. In the crystal, N—H—O hydrogen bonds involving the hydrazide and acetyl groups, which form R22(18) ring motifs, link the mol­ecules into dimers, which form columns along [010].

2-(4-Chlorophenyl)-N-(3,4-difluorophenyl)acetamide

Abstract: In the title compound, C14H10ClF2NO, the dihedral angle between the mean planes of the 4-chloro­phenyl and 3,4-di­fluoro­phenyl rings is 65.2 (1)°. These two planes are twisted by 83.5 (5) and 38.9 (9)°, respectively, from that of the acetamide group. In the crystal, N—H(...)O hydrogen bonds form infinite chains along [100]. Weak C—H(...)O and C—H(...)F inter­actions are also observed and stack mol­ecules along the b axis.

2-(3,4-Dichlorophenyl)-N-(1,3-thiazol-2-yl)acetamide

Abstract: In the title compound, C11H8Cl2N2OS, the mean plane of the dichlorophenyl ring is twisted by 61.8 (1)° from that of the thiazole ring. In the crystal, molecules are linked via pairs of N—H⋯N hydrogen bonds with an R 2 2(8) graph-set motif, forming inversion dimers which stack along the a-axis direction.

N-(4-Bromo­phen­yl)acetamide: a new polymorph

Abstract: A new polymorph of the title compound, C8H8BrNO, has been determined at 173 K in the space group P21/c. The previous room-temperature structure was reported to crystallize in the ortho­rhom­bic space group Pna21 [Andreetti et al. (1968). Acta Cryst. B24, 1195–1198]. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds forming chains along [010]. Weak C—H⋯π inter­actions are also present.

Crystal structure of (2E)-3-(biphenyl-4-yl)-1-(4,4’’-difluoro-5’-methoxy- 1,1’:3’,1’’-terphenyl-4’-yl)prop-2-en-1-one, C34H24F2O2

Abstract: Abstract C34H24F2O2, monoclinic, P21/c (no. 14), a = 15.6240(5) Å, b = 7.0828(2) Å, c = 24.3641(7) Å, β = 105.522(2)°, V = 2597.9 Å3, Z = 4, Rgt(F) = 0.0516, wRref(F2) = 0.1260, T = 200 K.

2-(4-Bromo-phen-yl)-N-(3,4-di-fluoro-phen-yl)acetamide.

Abstract: In the title compound, C14H10BrF2NO, the dihedral angle between the mean planes of the 4-bromo­phenyl and 3,4-di­fluoro­phenyl rings is 66.4 (1)°. These two planes are twisted by 40.0 (5) and 86.3 (2)°, respectively, from that of the acetamide group. In the crystal, N—H⋯O hydrogen bonds and weak C—H⋯O and C—H⋯F inter­actions form infinite chains along [100].

Synthesis, characterization and crystal structure of 3'-[(4-fluorophenyl)carbonyl]-5'-(hydroxymethyl)-4’-phenyl spiro[indole-3,2'-pyrrolidin]-2(1h)-one

Abstract: The title compound 3'-[(4-fluorophenyl)carbonyl]-5'-(hydroxymethyl)-4’-phenyl spiro[indole-3,2'-pyrrolidin]-2(1 H )-one is synthesized by the straightforward multicomponent reaction of 1-(4-fluorophenyl)-3-phenylprop-2-en-1-one, isatin and serine, and is crystallises in monoclinic space group C2/c.The molecule is essentially planar except one of the pyrrolidin ring which adopts normal envelope conformation. The supermoleular assembly is consolidated by ᴨ-ᴨ interactions [centroid- centroid distance= 3.7983(18)]. The crystal structure is stabilized by one C-H…O intra-hydrogen bond, two N-H…O and one O-H…N inter-hydrogen bonds, and these interactions links the molecules into chain extending along the b-axis.

Redetermination of the crystal structure of N-acetyl glycine (2-acetamidoacetic acid), C4H7NO3

Abstract: C4H7NO3, monoclinic, P21/c (no. 14), a = 4.8110(2) A, b = 11.5030(5) A, c = 9.7660(4) A, = 97.864(2)°, V = 535.4 A 3 , Z =4 ,Rgt(F) = 0.0356, wRref(F 2 ) = 0.1099, T = 200 K. Source of material In an Erlenmeyer flask, glycine (7.5 g, 0.1 mol) was suspended in water (30 mL) and stirred vigorously until complete dissolution had occurred. Acetic anhydride (21.5 g, 0.2 mol) was added in one portion and stirring was continued for 15–20 min. The solution was kept in a refrigerator overnight to effect complete crystallization. The crystals were collected by filteration and dried at 100–110 °C. The residue was recrystallized from boiling water, yield: 89%. Experimental details Carbon-bound H atoms were placed in calculated positions (C–H 0.99 A) and were included in the refinement in the riding model approximation, with Uiso(H) set to 1.2Ueq(C). The H atoms of the methyl group were allowed to rotate with a fixed angle around the C–C bond to best fit the experimental electron density (HFIX 137 in the SHELX program suite [11]), with Uiso(H) set to 1.5Ueq(C). The H atom of the hydroxyl group was allowed to rotate with a fixed angle around the C–O bond to best fit the experimental electron density (HFIX 147 in the SHELX program suite [11]), with Uiso(H) set to 1.5Ueq(O). The nitrogen-bound H atom was located on a difference Fourier map and refined freely. Discussion

2-(2,6-Dichloro­phen­yl)-N-(1,3-thia­zol-2-yl)acetamide

Abstract: In the title compound, C11H8Cl2N2OS, the mean plane of the dichloro­phenyl ring is twisted by 79.7 (7)° from that of the thia­zole ring. In the crystal, molecules are linked via pairs of N—H⋯N hydrogen bonds, forming inversion dimers which stack along the a-axis direction.

2'-[(4-Fluorophenyl)carbonyl]-1'-phenyl-1',2',5',6',7',7a'-hexahydrospiro[indole-3,3'-pyrrolizin]-2(1H)-one

Abstract: A new spiro[indole-3,3'-pyrrolizine] derivative is regioselectively synthesized by the straightforward multicomponent reaction of 1-(4-fluorophenyl)-3-phenylprop-2-en-1-one, isatin and L-proline without any catalyst. The structure of the newly synthesized compound is characterized by IR, NMR, UV-visible and mass spectral data. The compound is also screened for its reducing power assay.

4-Hy-droxy-N-methyl-benzamide.

Abstract: Three independent mol­ecules comprise the asymmetric unit of the title compound, C8H9NO2, in which the dihedral angles between the amide group and the benzene ring are 3.0 (2), 4.0 (3) and 3.3 (9)°. In the crystal, O—H⋯O hydrogen bonds and weak C—H⋯N inter­actions are observed, forming infinite chains along [101].

N-(1,3-Benzo-thia-zol-2-yl)acetamide.

Abstract: The title compound, C9H8N2OS, crystallizes with two mol­ecules (A and B) in the asymmetric unit. The dihedral angles between the mean planes of the 1,3-benzo­thia­zol-2-yl ring system and the acetamide group are 2.7 (4) (mol­ecule A) and 7.2 (2) A (mol­ecule B). In the crystal, pairs of N—H⋯N hydrogen bonds link the A and B mol­ecules into dimers, generating R22(8) loops. The dimers stack along [100].