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Some new class of amino isoxazolidine derivatives have been synthesized from α-amino nitrones in water with good to excellent yields. The new isoxazolidines are further functionalized into new scaffolds of peptides with good synthetic potentiality. Simple reaction methodology, greener approaches, atom efficiency, noninvolvement of catalysts, faster reaction conditions, excellent yields, and a new approach in peptide synthesis are the attractions in these syntheses.

α-amino nitrones are found to have a great significance in the synthesis of peptides. Simple reaction methodology, high yield, and atom efficiency in these reactions have made this protocol highly attractive. The synthetic route may be extended to the synthesis of dipeptides in enantiomerically pure form. Potential biological activity of the newly synthesized peptides is the major application in this new methodology.

α-amino nitrones are found to have a great significance in the synthesis of peptides. Simple reaction methodology, high yield, and atom efficiency in these reactions have made this protocol highly attractive. The synthetic route may be extended to the synthesis of dipeptides in enantiomerically pure form. Potential biological activity of the newly synthesized peptides is the major application in this new methodology.

Microwave-induced 1,3-dipolar cycloaddition reactions of dihydropyran derived nitrone with various activated alkenes have been studied in situ and found to afford new isoxazolidine derivatives with moderate selectivity.

1,3-Dipolar cycloaddition reactions of α-chloro and simple nitrones have been studied with novel α-N-methyl/phenyl furan derivatives as new dipolarophiles. The reactions are found to be highly regioselective to afford single 5-spiro isoxazolidines with high yield in a short reaction time.

Microwave-induced 1,3-dipolar cycloaddition reactions of nitrone (III) with activated alkenes such as (IV) and (VIII) provides access to new isoxazolidine derivatives.

Organic Chemistry Laboratory, Sikkim Government College, Gangtok-737 102, Sikkim, India E-mail : bchakraborty42@gmail.com Manuscript received 10 Marc/1 2011, revised 30 June 2011. accepted 23 August 2011 Microwave assisted 1,3-dipolar cycloaddition reaction of N-phenyl-α-amino nitrone with various alkynes as dipolarophile afforded novel isoxazoline derivatives with high synthetic potentials.

The present work describes dynamic uptake of the antibiotic drug ciprofloxacin hydrochloride (CH), by using a cost-effective agricultural by-product . sawdust (SD). The sawdust was characterised by FTIR and SEM analysis. The sorbent particles were highly porous with average pore diameter of nearly 10 ƒÊm. The optimum pH and solid/liquid ratio for sorption of CH were found to be 5.8 and 2.0, respectively. The dynamic drug uptake data was applied to various kinetic models and their order of fitness was found to be pseudo second order > Elovich equation > power function model, as indicated by their regression values. The experimental equilibrium uptake values (qe) were in close agreement with those evaluated from the pseudo second order equation for initial sorbate concentrations of 10 and 20 mgE.-1 at 33‹C. The drug uptake mechanism was found to be attractive non-electrostatic interactions, involving H-bonding interactions between H atoms and other electronegative species such as F, O and N of the drug molecule. The mechanism is discussed on the basis of pHpzc of sawdust and zwitterionic nature of drug CH. Mass transfer analysis was carried out using the drug uptake data obtained with sorbate concentrations of 10 and 20 mgE.-1. The used sorbent could be regenerated using 1.0 molE.-1 HCl solution with a regeneration efficiency of nearly 85%.

1,3-Dipolar cycloaddition reactions of α-chloro and simple nitrones have been studied with novel α-N-methyl/phenyl furan derivatives as new dipolarophiles. The reactions are found to be highly regioselective to afford single 5-spiro isoxazolidines with high yield in a short reaction time.