Efficient and Sustainable Synthesis of Biobased 8-Hydroxyquinoline with the Heterogeneous Catalytic System in Aqueous Media

Efficient and sustainable synthesis of value-added compounds based on biobased materials is consistent with the principles of green chemistry. Biobased chemicals are primarily synthesized from glucose and related feedstocks via two main routes: enzymatic catalysis for one-step synthesis and whole-cell catalysis for multistep synthesis, with the latter being more cost-effective than the former. However, due to the diversity of intracellular conversion pathways, whole-cell synthesis often exhibits a low atom economy for specific reactions. For example, in the key step of quinoline synthesis involving the construction of a nitrogen-containing six-membered ring, the conversion rate in the fermentation broth is less than 15%. To address this issue, we have developed a biochemical fusion preparation process that combines whole-cell synthesis of 2-aminophenol with the chemical catalytic technology. This approach enables the one-pot construction of C–N, C–C, and C═C bonds in situ within the fermentation broth, using 2-aminophenol and biobased acrolein as substrates, thereby efficiently synthesizing the nitrogen-containing six-membered ring and obtaining the target product, 8-hydroxyquinoline (8-HQ). The metal–organic framework catalyst was rationally designed with a Zr metal center for C–N bond formation and sulfonic acid group for C–C and C═C bond formation, while the pore size was optimized for efficient transformation at low substrate concentrations. This precise engineering strategy culminated in the performance of HI-UiO-66-SO3H-3.3, which delivers an 80.7% yield of 8-HQ within 3 h in aqueous solution. The synthesis efficiency of biochemical fusion catalysis is 6.36 times higher than that of conventional biological catalysis, achieving 200 mg·L–1·h–1. The recycling of water and catalyst exhibits clear advantages in terms of green chemistry metrics. In summary, this study achieved the synthesis of biobased 8-HQ in the biochemical fusion catalytic system, which provided the theoretical and experimental support for in situ green derivatization of biobased platform compounds.