Table 1 Justification of the principles of green chemistry.

Relevant Principles of Green Chemistry and analysis for the synthesis of alkoxybutenolide monomers from furfural.

Principles of Green ChemistryJustification
Less hazardous chemical synthesisIn the synthesis, starting from the platform chemical furfural, benign solvents (methanol and toluene) are used for the preparation of alkoxybutenolides. As vacuum distillation is used as the purification method, no other environmentally hazardous solvents are used.
Design for energy efficiencyThe oxidation of furfural is performed photochemically (visible light) at ambient temperature. Scalable photooxidation procedures with energy-efficient lamps (TL and LED) have been designed.
Use of renewable feedstocksFurfural, a platform chemical derived from the acid-mediated dehydration of lignocellulose (H2O as waste), is used as sole starting material for the synthesis of alkoxybutenolides (45, 46).
Reduce derivativesThe hemiacetal moiety in hydroxybutenolide B1 allows facile derivatization toward alkoxybutenolides without the use of protecting/activation groups.
CatalysisThe oxidation of furfural is photocatalytic using molecular oxygen, preventing the use of stoichiometric amounts of oxidants.
Inherently safer chemistry for accident preventionThe flow reactor designed for the upscaling of the photooxidation of furfural allows a safer handling of reactive substrates (pressurized oxygen) or intermediates (endoperoxide) as low concentrations, and no accumulation is present in flow (30).