Investigations on regio- and stereoselectivities in cycloadditions involving α- (3-pyridyl)-N-phenylnitrone: Development of an efficient route to novel nicotine analogs

Facile Synthesis of Some New Peptidomimetic β3 -and β2,3 -Amino Alcohols Possessing Pyridyl Moiety via Reductive Ring Opening of Pyridyl-isoxazolidines

Regio- and stereoselective 1,3-dipolar cycloadditions of C-(3-pyridyl)-N-phenylnitrone (2) with variedly substituted dipolarophiles (3, 4) were carried out to obtain substituted pyridyl-isoxazolidines (5-8). Reductive cleavage of pyridyl-isoxazolidines (5-8) with ammonium formate, methanol-THF solvents, at ambient temperature, in the presence of Pd/C provided a facile route for the synthesis of β3 -and β2,3 -amino alcohols (9-12), with a substitution pattern having pronounced influence on torsional angles. The obtained compounds (9-12) are valuable scaffolds which can be utilized for peptidomimetics. Thus, the present methodology for reductive opening of isoxazolidine ring avoids the disadvantages of using expensive apparatus and hazards involved in the use of hydrogen gas. The preferential formation of amino-alcohols in case of bicyclic isoxazolidines (8a-c), which precludes any recyclization is rationalized by DFT calculations.

Regio- and stereoselective synthesis of novel isoxazolidine heterocycles by 1,3-dipolar cycloaddition between C-phenyl-N-methylnitrone and substituted alkenes. Experimental and DFT investigation of selectivity and mechanism

A series of isoxazolidine heterocycles was synthesized through the 1,3-dipolar cycloaddition (13DC) reaction of C-phenyl-N-methylnitrone with different substituted alkenes.

PASS assisted prediction and pharmacological evaluation of novel nicotinic analogs for nootropic activity in mice

The aim of present study is to predict the probable nootropic activity of novel nicotine analogues with the help of computer program, PASS (prediction of activity spectra for substances) and evaluate the same. Two compounds from differently substituted pyridines were selected for synthesis and evaluation of nootropic activity based on their high probable activity (Pa) value predicted by PASS computer program. Evaluation of nootropic activity of compounds after acute and chronic treatment was done with transfer latency (TL) and step down latency (SDL) methods which showed significant nootropic activity. The effect on scopolamine induced amnesia was also observed along with their acetylcholine esterase inhibitory activity which also showed positive results which strengthened their efficacy as nootropic agents through involvement of cholinergic system. This nootropic effect was similar to the effect of nicotine and donepezil used as standard drugs. Muscle coordination and locomotor activity along with their addiction liability, safety and tolerability studies were also evaluated. These studies showed that these compounds are well tolerable and safe over a wide range of doses tested along with the absence of withdrawal effect which is present in nicotine due to its addiction liability. The study showed that these compounds are true nicotine analogs with desirable efficacy and safety profile for their use as effective nootropic agents.