Efficient, Environmentally Sustainable Approach for Aromatic Nitration
These biocatalysts can generate novel nitroaromatic end products and building blocks for the synthesis of more complex compounds in an environmentally friendly manner. Nitro aromatic and heterocyclic derivatives are important industrial chemicals that are used as food additives, pesticides, herbicides, polymers, dyes and pharmaceuticals. Small nitroaromatics are common building blocks of complex molecules in chemical synthesis and chemical aromatic nitration is widely used in organic synthesis. However, the current processes are not environmentally sound and have other challenges including poor selectivity, low yield, and generation of multiple isomers and by-products. Researchers at the University of Florida have developed a biocatalyst system that is capable of transferring a nitro group onto an indole moiety of a variety of tryptophan analogues with greater efficiency, a higher degree of selectivity, and minimal environmental impact.
Biocatalyst-based aromatic nitration reaction transfers the nitro functional group to the indole structural core motif with greater efficiency and a higher degree of selectivity than current processes. These biocatalysts can generate nitroaromatics in an environmentally friendly manner and this approach can be used for the generation of novel nitroaromatics.
- Introduces direct aromatic nitration, eliminating environmentally unfriendly by-products
- Enzymes increase regio- and stereo-selectivity of added nitro group, increasing yield and reducing the generation of multiple isomers
- Boosts functional group tolerance, expanding its use in generating products with specific requirements
This nitration process utilizes biocatalysts to add a nitro group to aromatic molecules. The biocatalysts are engineered as “self-sufficient enzymes,” meaning they are able to perform their function without adding any auxiliary redox proteins. Researchers create them by fusing the nitration-promoting P450 with reductase domains of irrelevant P450s from Bacillus megatorium and Rhodococcus species. The engineered self-sufficient cytochrome P450 enzymes are capable of nitrating the indole of L-tryptophan analogues carrying one or more substituents on the indole, using nitric oxide and oxygen as co-substrates.