Synthesis of sulfur containing dihydro-pyrrolo derivatives and their biological evaluation as antioxidants

The 1,3-dipolar cycloaddition to N-phenylmaleimide of azomethine ylides, generated in situ from sulfanyl-substituted imines of glycine esters, yields 5H-dihydro-pyrrolo products with syn diastereoselectivity. The syn (major) and anti (minor) products were isolated chromatographically and fully characterized by spectroscopic methods and in two cases also by X-ray analysis. The diastereomeric cycloadducts were tested for their antioxidant activity with good results.

Synthesis of Highly Functionalized Pyrrolidines via a Mild One-Pot, Three-Component 1,3-Dipolar Cycloaddition Process

[reaction: see text] A simple and efficient one-pot, three-component synthesis of highly functionalized pyrrolidines via cascade imine --> azomethine ylide --> 1,3-dipolar cycloadditions is reported. Admixing a variety of aldehydes, dimethyl 2-aminomalonate, and electron deficient alkenes in THF leads to the clean production of pyrrolidines in good to excellent yields. The mild reaction conditions enabled the generation of previously inaccessible azomethine ylides from enolizable aldehydes. Endo selectivity was exclusive with N-phenyl maleimide and maleic anhydride. Good chemo-, regio-, and stereoselectivities were observed with methyl acrylate, though catalysis by Ag(I) was necessary with this dipolarophile.

Parallel solution- and solid-phase synthesis of spiropyrrolo-pyrroles as novel neurokinin receptor ligands

The combination of a 3,5-bis(trifluoromethyl)phenyl needle with the spiropyrrolo-pyrrole motive as a privileged GPCR scaffold was the basis for designing a focused combinatorial library targeted towards the neurokinin-1 receptor. A solution- and solid-phase method is described and binding affinities of representative compounds are presented.

Methylation of L-trans-2,4-pyrrolidine dicarboxylate converts the glutamate transport inhibitor from a substrate to a non-substrate inhibitor

The 4-methyl analogue of the potent inhibitor of CNS L-glutamate neurotransmitter transporters, L-trans-2,4-PDC, was synthesized via a 1,3-dipolar cycloaddition reaction sequence. The bioassays performed not only exhibit increased potency of the methylated derivative over L-trans-2,4-PDC, but also exhibit non-substrate properties at the rat forebrain synaptosomal glutamate transporter while the parent L-trans-2,4-PDC exhibits substrate properties. These results support two hypotheses developed for distinguishing the physiological properties of transport inhibitors based on molecular modeling studies, and are reported here.