Synthesis of Quinone Methide Substituted Neonicotinoid Derivatives via 1,6-Conjugate Addition of N-Benzyl Nitro Ketene Aminals with para-Quinone Methides Accompanying Oxidation

Abstract

A concise and efficient route for the synthesis of quinone methide substituted neonicotinoid derivatives (4–5) via the one-pot Cs2CO3-catalyzed 1,6-conjugate addition of N-benzyl nitro ketene amines (2) or 1,1-enediamines (3) with para-quinone methides (1) in acetone and an oxidation reaction using atmospheric oxygen has been developed. This protocol represents a route to obtain a novel class of quinone methide substituted neonicotinoid derivatives in a concise, rapid, and practical manner. This reaction is particularly attractive because of the following features: low-cost and biocompatible solvent, mild temperature, atomic economy, high yields, and potential biological activity of the product.

Stereoselective Synthesis of Tri- and Tetrasubstituted Olefins via 1,6-Additions of Diazo Compounds and Their Precursors to p-Quinone Methides

“…Initially, the base (KOH) abstracts a proton from the active methylene compound 9 to generate the enolate ion VII , which then adds to p -QM 1 in a 1,6-fashion to form adduct 10 . Further deprotonation of 10 and stabilization of the resulting enolate IX via keto–enol tautomerism weakens the doubly benzylic C–H bond, thereby facilitating aerial oxidation to corresponding quinone VIII . Later, the quinone VIII undergoes rearomatization to afford the tetrasubstituted olefin 7 .…”

Uncatalyzed Addition and Cyclization of T_SN₃to 1,1-Enediamines: An Effective Green Route to Highly Functionalized 1,2,3-Triazole Compounds

“…All chemicals and solvents were used as received without further purification unless otherwise stated. Compounds 1 were obtained according to the literature [37][38][39][40][41].…”

“…1,1-Enediamines (EDAMs) are fascinating and versatile building blocks that are widely used to synthesize various heterocyclic compounds [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Many of these compounds have a wide range of biological activities, such as antitumor [53][54][55], pesticide [56][57][58], and others.…”

Catalyst-Free 1,6-Conjugate Addition/Aromatization/Sulfonylation of para-Quinone Methides: Facile Access to Diarylmethyl Sulfones

“…To address these limitations, developing efficient, green, and sustainable strategies to construct diarylmethyl sulfones remains important and is challenging. In continuation of our interest in constructing functionalized molecules, − herein, we report a catalyst-free, facile, and efficient route for the synthesis of diarylmethyl sulfones from the readily available starting materials, sulfonyl hydrazides , and p -quinone methides ( p -QMs), − which are widely used in modern organic synthesis because of the assembly of carbonyl and olefinic moieties (Figure b).…”