Visible-light-induced synthesis of 2,4-disubstituted quinolines from o-vinylaryl isocyanides and oxime esters

A visible-light-induced radical cyclization reaction of o-vinylaryl isocyanides and oxime esters to access various 2,4-disubstituted quinolines was disclosed. Oxime esters were employed as acyl radical precursors via the carbon-carbon bond cleavage. It provided an effective way for the synthesis of 2-acyl-4-arlysubstituted quinolines under mild conditions and exhibited good functional group tolerance and substrate applicability.

Synchronous catalytic depolymerization of alkaline lignin to monophenols with in situ-converted hierarchical zeolite for bio-polyurethane production

Catalytic depolymerization of lignin to high-value chemicals is crucial to the comprehensive achievement of sustainable and economic concerns. Herein, we propose a green, practical, and economic strategy for the synchronous catalytic depolymerization of lignin based on in situ conversion of geopolymer precursor to hierarchical zeolite, using water as a mild solvent and without external H₂, additives, co-catalysts or co-solvents. The in situ-converted hierarchical analcime (ANA) zeolite outperformed previously reported representative catalysts, such as PTA/MCM-41 and CuAlMgO_x in lignin depolymerization with a high monophenol yield (95.61 ± 7.89 mg/g). The synergetic effect of the micro-mesoporous structure and enhanced acidic sites of the ANA played a vital role in regulating the monomer composition and the yield of monophenols. The obtained monophenols are rich in -OH groups and can be utilized as a substitute for petroleum resources, such as ethylene glycol or glycerin for the synthesis of bio-polyurethane foams (bio-PUFs). This work expands the scope of using biomass in a sustainable manner to make high-value chemicals and biomaterials.