Exploring selectivity requirements for peripheral versus central benzodiazepine receptor binding affinity: QSAR modeling of 2-phenylimidazo[1,2-a]pyridine acetamides using topological and physicochemical descriptors.

Considering the potential of peripheral benzodiazepine receptor (PBR) ligands in therapeutic applications and clinical benefit in the management of a large spectrum of different indications, quantitative structure-activity relationship (QSAR) study has been attempted to explore the structural and physicochemical requirements for selectivity of 2-phenylimidazo[1,2-a]pyridineacetamides for binding with peripheral over central benzodiazepine receptors (CBRs). For PBR binding affinity, molar refractivity (MR) shows a parabolic relation with binding affinity suggesting that binding affinity increases with increase in volume of the compounds, until it reaches the critical value, after which the affinity decreases. The negative coefficients of S_aaN and S_ssNH indicate that binding affinity increases with decrease in E-state value of (N/) (aromatic nitrogen) and HN< (secondary amino group) fragments. The coefficient of 3XVC and JX term indicates the importance of shape and branching for binding affinity. For CBR binding affinity, lipophilicity of molecules is detrimental to the binding affinity, while presence of hydrogen at Y position is conducive to the activity. Selectivity pattern of these ligands for peripheral (cortex) over central receptors requires the presence and absence of methyl group at R2 and R3 positions respectively, and shows the importance of MR and shape parameter. Similarly, selectivity of these ligands for peripheral (ovary) over central receptors requires the presence and absence of methyl group at R2 and R3 positions respectively, presence of phenyl group at R1 and R2 positions and selectivity relation shows importance of MR, shape and branching.

Synthesis and antimicrobial activity of 3,5-bis- [1-3,4-oxadiazol-5-yl] -, [1,3-thiazolo] hydrazony1-and [7H] s-Triazolo- [3,4-b] -1,3,4 Thiadiazinyl] pyridine derivatives

Different 3, 5-bis [oxadiazolyl] pyridine derivatives 3-5 have been obtained from 1 depending on the reaction condition. Reaction of 5 with amines or alkylhalides afforded the corresponding Mannich bases 6 or s-alkyl derivatives 7. The latter derivatived were treated with ammonium acetate to give 9 and with hydrazine hydrate affording bis bicyclic pyridine derivatives 10. Preliminary antimicrobial tests showed products 6e and 8 to possess higher activity when compared with oxytetracycline

Synthesis of some new benzimidazole derivatives as antimicrobial agents

Synthesis of 2-[p-4-aryl-3-cyano-2-oxo[IH] pyridin-6-yl] anilino] benzimidazoles [2a-g] and the 2-[p-[4-aryl-3-cyano-2-imino[IH] pyridin-6-yl] anilino] benzimidazoles [3a-g] were obtained in one step reaction between the 2-[p-acetylanilino] benzimidazole [1] with ethyl cyanoacetate and/or malononitrile and the appropriate aldehydes in the presence of ammonium acetate. The new compounds showed considerable antimicrobial activity against Gram +ve, Gram -ve bacteria, yeast and fungi

New antimicrobial quinazolinone derivatives

A series of quinazolin-4-ones incorporated with pyridones, iminopyridines, thiazole, semicarbazone and thiosemicarbazone moieties were synthesized. Some tested compounds showed considerable biological activity against some microorganisms

Synthesis of certain new pyridine derivatives of expected pharmacological activity

In this investigation, some new pyridyl-s-triazole, pyridyl oxadiazoline and pyridyl-s-triazole [3-4-b]-1,3,4-thiadiazole derivatives have been synthesize and characterized by elemental and spectral analyses

Ionization potentials and electron affinities of nicotinic acid and nicotinamide calculated with HAM/3

Ionization potentials and electron affinities of nicotinic acid and nicotinamide were calculated by HAM/3. Observed photoelectron spectra of the molecules were analyzed with the aid of the calculated ionization potentials. Chemical reactivity of the molecules was discussed.

Conformational Equilibria in 1, 3-Azabicyclic Systems

La comparación de los parámetros de RMN'H para la perhidro-oxazolo (3,4-a) piridina (Jgem-2.5 Hz, delta4.40,3.81 ) con los 6-etilderivados 7 y 8, muestra la existencia de un equilibrio conformacional entre los conformadores trans-fusionado y el O-interno del cis-fusionado. La espectroscopia de RMN a bajas temperaturas permitió observar señales para ambos conformadores; y la integración de estas señales indican un equilibrio existente a 18ºK entre el 73 por ciento de 3-t y el 27 por ciento de 3-c

Chemical and biological reactivity of newly synthesized 2-chloro-6-ethoxy -4-acetylpyridine

Alpha, Beta UNSATURATED ketones are very important compounds for their high reactivity usefulness in organic synthesis as key starting materials to form various classes of biologically active compounds[1-4]. As far as we know, reported investigations dealing with the use of alpha, beta - unsaturated ketones incorporating two heterocyclic moieties[1-3] were not extended to substituted pyridine in this connection-, 2,6- dichloroisonicotinic acid l[5] was selected to undertake this course of investigation, due to the broad spectrum biological features[6-9] of its derivatives. The acetyl derivative of 1 required for the synthesis of the designed 4-cinnamoyl pyridines was obtained by Claisen- condensation of ethyl ester of 1 with ethyl acetate in the presence of sodium ethoxide. The reaction was undertaken under the same conditions described by Barrus and Powell[10] followed by cleavage of the condensation product 2 with sulfuric acid to afford 2-chloro -6- ethoxy -4-acetylpyridine 4 in 45 percent yield. An unexpected product, identified as, 2-chloro -6-ethoxy -4- pyridinecarboxylic acid 3[11] was isolated, along with product 4. The Structure of 4 was furnished according to its elemental and spectral features. Formation of 3 could be attributed to partial hydrolysis of 2

Kinetics of reaction of P-chloranil with pyridine in aqueous dioxane

The rate of reaction of p-chloranil with pyridine has been measured in different dioxane-water mixtures at different temperatures. The reaction is found to follow an overall third order kinetics, first with respect to chloranil and second with respect to pyridine. The reaction rate increases with increasing dielectric constant of the medium. A mechanism involved in the rate-determining steps, has been proposed for the reaction. Various activation parameters have been calculated and discussed