Synthesis, Characterization, and Evaluation of Cytotoxicity of Poly(3-methylene-2-pyrrolidone)

Computational Chemistry-Assisted Highly Selective Radical Cascade Cyclization of 1,6-Enynes with Thiols: Access to Sulfur-Substituted 4-Enyl-2-Pyrrolidones

In this study, an efficient method for the synthesis of sulfur-substituted 4-enyl-2-pyrrolidones was successfully developed through AIBN-promoted highly selective 5-exo-dig radical cascade cyclization of 1,6-enynes with sulfur sources with the aid of theoretical and computational chemistry. This protocol enables the first practical and green synthesis of an array of 4-enyl-2-pyrrolidones in moderate-to-good yields with broad substrate scopes and high regioselectivities (>20:1). Moreover, excellent stereoselectivities have also been achieved (up to >20:1, Z/E). Most interestingly, when the sulfur source is electron-rich thiophenol, reverse stereoselectivities were discovered. In addition, the control experiments indicate that the cascade cyclization is realized by radical reactions, and the detailed reaction mechanism and regioselectivities have also been explained by theoretical studies.

Reversible deactivation radical (co)polymerization of dimethyl methylene oxazolidinone towards responsive vicinal aminoalcohol-containing copolymers

Well-defined oxazolidinone-containing copolymers produced by controlled radical polymerization give access to multi-responsive vicinal amino-alcohol functional poly(vinyl alcohol)s.

Natural α-methylenelactam analogues: Design, synthesis and evaluation of α-alkenyl-γ and δ-lactams as potential antifungal agents against Colletotrichum orbiculare

In our continued efforts to improve the potential utility of the α-methylene-γ-lactone scaffold, 62 new and 59 known natural α-methylenelactam analogues including α-methylene-γ-lactams, α-arylidene-γ and δ-lactams, and 3-arylideneindolin-2-ones were synthesized as the bioisosteric analogues of the α-methylenelactone scaffold. The results of antifungal and cytotoxic activity indicated that among these derivatives compound (E)-1-(2, 6-dichlorobenzyl)-3-(2-fluorobenzylidene) pyrrolidin-2-one (Py51) possessed good selectivity with the highest antifungal activity against Colletotrichum orbiculare with IC₅₀ = 10.4 μM but less cytotoxic activity with IC₅₀ = 141.2 μM (against HepG2 cell line) and 161.2 μM (against human hepatic L02 cell line). Ultrastructural change studies performed by transmission electron microscope showed that Py51 could cause important cell morphological changes in C. orbiculare, such as plasma membrane detached from cell wall, cell wall thickening, mitochondria disruption, a dramatic increase in vacuolation, and eventually a complete loss in the integrity of organelles. Significantly, mitochondria appeared one of the primary targets, as confirmed by their remarkably aberrant morphological changes. Analysis of structure-activity relationships revealed that incorporation of the aryl group into the α-exo-methylene and the N-benzyl substitution increased the activity. Meanwhile, the α-arylidene-γ-lactams have superiority in selectivity over the 3-arylideneindolin-2-ones. Based on the results, the N-benzyl substituted α-(2-fluorophenyl)-γ-lactam was identified as the most promising natural-based scaffold for further discovering and developing improved crop-protection agents.