Lossen Rearrangement Reaction of Aromatic and Aliphatic Hydroxamates

The main goal of this research is to explore a potential of the most green and non-toxic possible route to the synthesis of industrially important chemicals, such as isocyanates and amines, based on the bio-based starting materials. In this work, we demonstrated the synthesis of 1,4-diisocyanatobenzene and 1,4- diisocyanatobutane in three steps. First step is the synthesis of hydroxamic acid, second step involves a conversion of the hydroxamic acid to its corresponding hydroxamate, and the final step is the transformation of the hydroxamate into the corresponding isocyanate by Lossen rearrangement reaction. The starting materials for PPDI and BDI are diethyl terephthalate and dimethyl adipate, respectively. Both esters are derivatives of acids that are now available from biomass. The final products were characterized IR, NMR, MS, TGA, and DSC.