Biomass to Aromatic Amine Module: Alkali Catalytic Conversion of N‐Acetylglucosamine into Unsubstituted 3‐Acetamidofuran by Retro‐Aldol Condensation

An alkali catalytic system for the selective conversion of N-acetyl-d-glucosamine (NAG) into unsubstituted 3-acetamidofuran (3AF) via retro-aldol condensation has been developed. 3AF with 73.9 % yield is obtained in the presence of a ternary Ba(OH)₂−H₃BO₃−NaCl catalytic system.

Abstract

Aminofurans are widely used in drug synthesis as aromatic modules analogous to aniline. However, unsubstituted aminofuran compounds are difficult to prepare. In this study, a process for the selective conversion of N-acetyl-d-glucosamine (NAG) into unsubstituted 3-acetamidofuran (3AF) is developed. The yield of 3AF from NAG catalyzed by a ternary Ba(OH)₂−H₃BO₃−NaCl catalytic system in N-methylpyrrolidone at 180 °C for 20 min can reach 73.9 %. Mechanistic studies reveal that the pathway to 3AF starts with a base-promoted retro-aldol condensation of the ring-opened NAG, affording the key intermediate N-acetylerythrosamine. Judicious selection of the catalyst system and conditions enables the selective conversion of biomass-derived NAG into 3AF or 3-acetamido-5-acetylfuran.

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