Pyridines from Biomass

Mechanism + Description

Pyridines from lignin

Aldehydes / ketones in biomass or formed on pyrolysis react with ammonia and aromatize via elimination of oxidation.

General comments

A number of routes have been described that produce pyridines directly from biorenewable feedstocks. Pyrolysis of biomass with ammonia or ammonia derivatives can give pyridines , but synthetic utility is currently somewhat limited by low yields and complex mixtures.

A better strategy toward single pyridine structures is to employ synthetic biology approaches to make single pyridines in a fermentation using modified microorganisms. Routes toward pyridine carboxylic acids using lignin as a feedstock have been described.

Pyridines can be synthesized from furans. A number of these starting materials can be produced from renewable biomass feedstocks like C6 and C5 sugars.

Key references

Mycroft, Z.; Gomis, M.; Mines, P.; Law, P.; Bugg, T. D. H. Biocatalytic conversion of lignin to aromatic dicarboxylic acids in Rhodococcus jostii RHA1 by re-routing aromatic degradation pathways. Green Chem., 2015, 17, 4974–4979.

Spence, E. M.; Calvo‑Bado, L.; Mines, P.; Bugg, T. D. H. Metabolic engineering of Rhodococcus jostii RHA1 for production of pyridine-dicarboxylic acids from lignin. Microb Cell Fact. (2021) 20:15.

Xu, L.; Yao, Q.; Han, Z.; Zhang, Y.; Fu, Y. Producing Pyridines via Thermocatalytic Conversion and Ammonization of Waste Polylactic Acid over Zeolites. ACS Sustain. Chem. Eng. 2016, 4, 1115−1122.

Li, H.; Guo, H.; Fang, Z.; Aida, T. M.; Smith, Jr. R. L. Cycloamination strategies for renewable N-heterocycles. Green Chem. 2020, 22, 582–611.

Scale-up example

Green Chem. 2020, 22, 6047–6054.
150 g scale