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3‐Acetamido‐5‐acetylfuran (3A5AF) is a potential platform compound for the production of nitrogen‐containing pharmaceuticals and chemicals. 3A5AF can be obtained by dehydration of chitin or its monomer, N‐acetylglucosamine (NAG). Here, we examined the use of solid catalysts for the dehydration of NAG to 3A5AF to achieve a more economical process that uses a recyclable catalyst. NAG was dehydrated using various solid catalysts in the presence of NaCl and N,N‐dimethyl acetamide as solvent at 433 K. The yield of 3A5AF with the solid catalysts decreased in the following order: Al‐exchanged montmorillonite>H‐ZSM‐5 (SiO2/Al2O3=40)>H‐montmorillonite (K‐10)>Amberlyst15>H‐ZSM‐5 (SiO2/Al2O3=300)>TiO2>γ‐Al2O3>ZrO2>SiO2 ⋅ MgO>Na‐montmorillonite. The highest yield of 3A5AF (14 %) was obtained with the Al‐exchanged montmorillonite. The montmorillonite catalysts were characterized by using inductively coupled plasma optical emission spectroscopy, energy‐dispersive X‐ray spectroscopy, N2 adsorption, Fourier‐transformed infrared spectroscopy, X‐ray diffraction, and 27Al magic‐angle spinning nuclear magnetic resonance spectroscopy (MAS‐NMR). In addition, a combined catalyst of Al‐exchanged montmorillonite and Cl− from synthetic hydrotalcite was found to be an active and recyclable solid catalyst for NAG dehydration to 3A5AF. [ABSTRACT FROM AUTHOR]

Chitosan oligosaccharide and its derivatives are known for their diverse biological activities. In this study, we communicate a convenient one‐pot synthesis of N,N‐dimethyl chitosan oligosaccharide (DMCOS) from chitin via acid‐catalyzed tandem depolymerization‐deacetylation‐N‐methylation pathway using formaldehyde as the methylation reagent. The synthesis protocol offers 77 % DMCOS that features a high degree of deacetylation, a high degree of methylation, and a low average molecular weight. Compared to chitosan, DMCOS exhibits superior antifungal activity against Candida species. Mechanism study reveals a previously non‐reported hydroxyl group‐assisted effect that facilitates the reductive amination reaction under strong acidic conditions. Overall, our findings demonstrate the feasibility of direct synthesis of DMCOS from chitin, highlighting its potential use in anti‐fungal applications. [ABSTRACT FROM AUTHOR]

Abstract: A shell biorefinery would involve fractionation of crustacean shells and incorporation of the components into value‐added products, particularly those that contain nitrogen. In a proof‐of‐concept study that validates this concept, the anticancer alkaloid proximicin A has been synthesized from the chitin‐derived platform chemical 3‐acetamido‐5‐acetylfuran (3A5AF). This study accentuates the leading role chitin is likely to play in the sustainable production of nitrogen‐containing fine chemicals that are not directly attainable from lignocellulose. [ABSTRACT FROM AUTHOR]

Front Cover: One-Pot Chitin Conversion to High-Activity Antifungal N,N-Dimethyl Chitosan Oligosaccharides (ChemSusChem 16/2023) Keywords: chitin; chitosan oligosaccharide; N-methylation; antifungal activity; shell biorefinery EN chitin chitosan oligosaccharide N-methylation antifungal activity shell biorefinery 1 1 1 08/24/23 20230821 NES 230821 B The Front Cover b shows chitin-derived oligosaccharides from marine biomass as powerful antimicrobial "weapon" through the "booster" containing formaldehyde. Chitin, chitosan oligosaccharide, N-methylation, antifungal activity, shell biorefinery. [Extracted from the article]