Elusive Dehydroalanine Derivatives with Enhanced Reactivity

Abstract

For the first time, a simple methodology for the chemical synthesis and use of highly reactive 4‐methylenoxazol‐5(4H)‐ones from serine is presented. These dehydroalanine derivatives, which resemble the natural 4‐methylidenimidazole‐5‐one (MIO) cofactor present in lyases and aminomutases, undergo rapid reaction with carbon nucleophiles such as silyl enol ethers, as well as cycloaddition reactions with diazo compounds and reactive dienes, under very mild conditions and without any need for metal catalysts or ring‐strain activation, offering potential for bioconjugation.

Online Grooming: de los juegos en línea a la obtención de material de abuso sexual.

“…Como se menciona si existen características de las personas con un trastorno psiquiátrico como lo es la pedofilia de acuerdo con los criterios del manual diagnóstico y estadístico de los trastornos mentales DSM-5 el primer criterio que se presenta es la excitación y la edad de los menores y agresores (Pérez-Aydillo, 2019). Como se menciona, hay elementos o características de los abusadores la mayoría pertenecen a el sexo masculino, no todos los abusadores sexuales hacen uso de la violencia es un porcentaje minoritario, sus estrategias se basan en persuasión y manipulación, en aquellos casos de abuso sexual intrafamiliar hacia niños, niñas y adolescentes los abusadores sexuales buscan oportunidades a través de la cercanía y confianza de la víctima.…”

Synthesis of Nβ-Substituted α,β-Diamino Acids via Stereoselective N-Michael Additions to a Chiral Bicyclic Dehydroalanine

“…Conventional Dha derivatives are normally poor Michael acceptors 41 so that strong bases or acids are needed to enhance their reactivity towards nucleophilic addition. We have recently described two different strategies to activate the Dha backbone by embedding it into achiral 42 and chiral cyclic scaffolds. 43 Initially, we reported the synthesis of a chiral Dha derivative 1', which was used in stereoselective S-Michael additions, showing excellent Michael acceptor properties, cleanly reacting with thiols using a base, under -78 ºC.…”