Balakrishna Kalluraya

Regioselective reaction: synthesis, characterization and pharmacological studies of some new Mannich bases derived from 1,2,4-triazoles.

In the present investigation, a series of new 4[(3-substituted-1H-pyrazol-4-yl)methyleneamino]-5-substituted-2-[(4-methylpiperzine-1-yl)methyl]-2H-1,2,4-triazole-3(4H)-thiones (4) were synthesized by the aminomethylation of 4-(3-substituted-1H-pyrazol-3-yl)methyleneamino-5-substituted-4H-1,2,4-triazole-3-thiols (3) with formaldehyde and N-methylpiperzine. These newly synthesized Schiff and Mannich bases were characterized by IR, (1)H NMR, mass spectral data and elemental analyses. These compounds were screened for their antibacterial and antifungal activity. Some of the compounds were found to exhibit significant antimicrobial activity.

Synthesis and pharmacological properties of some quinoline derivatives.

A series of 2-(2-thienyl) cinchoninic acids 3, their derivatives 5 and 4-(3-substituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazolo-6-yl)-2-( 2-thienyl) quinolines 6 were synthesized. The structures of the newly synthesized compounds are confirmed by analytical, IR, NMR and mass spectral data. The newly synthesized compounds were evaluated for their anti-inflammatory, analgesic and anthelmintic activity. The results indicated that dinitrothiophene derivatives 5 are more active.

Synthesis, characterization and biological activities of some new benzo[b]thiophene derivatives.

Benzo[b]thiophene molecules are found to be important tools in synthetic medicinal chemistry. They are of current interest due to their wide spectrum of pharmacological properties. In view of the biological activities of benzo[b]thiophene containing molecules, in this present research work, we propose the synthesis of some new benzo[b]thiophene derivatives such as thiadiazoles, oxadiazoles, pyrazolin & diaryl pyrazoles starting from 3-chlorobenzo[b]thiophene-2-carboxyl chloride. These newly synthesized compounds were characterized by elemental analyses, I.R, NMR and Mass spectral studies. Some of the selected compounds were screened for their antibacterial, antifungal and anti-inflammatory studies. Many of the molecules were found to be potent.

Synthesis, structural characterization, crystallographic analysis and antibacterial properties of some nitrofuryl triazolo[3,4-b]-1,3,4-thiadiazines

Abstract A series of 1-(5-nitro-2-furyl)-2-bromo-3-aryl-2-propen-1-ones has been prepared through dehydrobromination of 2,3-dibromo-1-(5-nitro-2-furyl)-3-arylpropan-1-ones. Condensation of 1-(5-nitro-2-furyl)-2-bromo-3-aryl-2-propen-1-ones with 4-amino-5-mercapto-1,2,4-triazoles afforded a new class of 6-(5-nitro-2-furyl)-7-arylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines. The structure of the condensation products are fully confirmed by analytical, IR, NMR and mass spectral data. The formation of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines rather than 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines in the above condensation has also been confirmed by X-ray crystallographic analysis. The newly synthesized compounds have been screened for their in vitro antibacterial activity against Gram-positive and Gram-negative bacteria.

Synthesis and pharmacological study of 1-acetyl/propyl-3-aryl-5-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-pyrazoline

A series of 1-acetyl/propyl-3-aryl-5-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-pyrazolines were synthesized in one step by condensing suitably substituted propenones, hydrazine and acetic/propionic acid. The newly synthesized pyrazolines were characterized by analytical and spectral data. The new compounds were screened for analgesic and anti-inflammatory activity and most of them showed good activity comparable with that of standard drugs Pentazocin and Diclofinac sodium respectively.

Regioselective reaction: synthesis and pharmacological study of Mannich bases containing ibuprofen moiety.

A series of 4-[(4-aryl)methylidene]amino-2-(substituted-4-ylmethyl)-5-{1-[4-(2-methylpropyl)phenyl]ethyl}-2,4-dihydro-3H-1,2,4-triazole-3-thione (6) were synthesized from an arylpropionic acid namely, ibuprofen by a three-component Mannich reaction. Aminomethylation of 4-[(4-aryl)methylidene]amino-5-{1-[4-(2-methylpropyl)phenyl] ethyl}-4H-1,2,4-triazole-3-thiol (5) with formaldehyde and a secondary amine furnished this novel series of Mannich bases (6). Both Schiff bases (5) and Mannich bases (6) were well characterized on the basis of IR, NMR, mass spectral data and elemental analysis. They were screened for their anti-inflammatory, analgesic, antibacterial and antifungal activities. Some of the Mannich bases (6) carrying morpholino and N-methylpiperazino residues were found to be promising anti-inflammatory and analgesic agents.

4-Chloro-N′-[(Z)-4-nitro­benzyl­idene]benzohydrazide monohydrate

In the title compound, C14H10ClN3O3·H2O, the benzohydrazide group is not planar and the molecule exists in a cis configuration with respect to the methylidene unit. The dihedral angle between the two substituted benzene rings is 38.7 (3)°. In the crystal structure, molecules are linked by O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds into a two-dimensional network parallel to the (100) plane. The crystal structure is further stabilized by weak C—H⋯O interactions.

Synthesis and antimicrobial activities of a new series of 4-S-[41-amino-51-oxo-61-substituted benzyl-41,51-dihydro-11,21,41-triazin-3-yl]mercaptoacetyl-3-arylsydnones

The synthesis of some 4-S-(4(1)-amino-5(1)-oxo-6(1)-substituted benzyl-4(1),5(1)-dihydro-1(1),2(1),4(1)-triazin-3-yl)mercaptoacetyl-3-arylsydnones by the reaction of 3-aryl-4-bromoacetylsydnones with 6-substituted-4-amino-3-mercapto-1,2,4-triazin-5-ones is described. The IR, (1)H NMR, mass spectra and elemental analysis characterized the newly synthesized compounds. The synthesized compounds were screened for their antimicrobial activity. All the compounds showed higher activity than that of standard drug during antimicrobial studies and the activity was comparable with the standard drug for antifungal activity.

Regioselective reaction: Synthesis, characterization and pharmacological activity of some new Mannich and Schiff bases containing sydnone

A novel series of 1-substituted aminomethyl-3-[1-(4-isobutylphenyl)ethyl]-4-(3-aryl-4-sydnonylidene) amino-1,2,4-triazol-5-thiones (9), was prepared from the 3-[1-(4-isobutylphenyl)ethyl]-4-(3-aryl-4-sydnonylidene) amino 5-mercapto-1,2,4-triazoles (8) by aminomethylation with formaldehyde and secondary amine. The structures of Schiff bases (8) and Mannich bases (9) were characterized on the basis of IR, NMR, mass spectra1 data and elemental analysis. The newly synthesized compounds were screened for their anti-inflammatory and analgesic activities. Mannich bases (9) carrying piperidine and morpholine residues showed promising anti-inflammatory and analgesic activity.

4-Chloro-N′-[(Z)-4-(dimethyl­amino)benzyl­idene]benzohydrazide mono­hydrate

In the title compound, C16H16ClN3O·H2O, the dihedral angle between the two aromatic rings is 44.58 (11)°. The N atom of the dimethylamino group adopts a pyramidal configuration. In the crystal structure, molecules are linked into a two-dimensional network parallel to the (001) plane by intermolecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds involving the water molecule and C—H⋯Cl hydrogen bonds. In addition, C—H⋯π interactions are observed.