Bio-based synthesis of cyclopentane-1,3-diamine and its application in bifunctional monomers for poly-condensation

A novel and green route for the synthesis of cyclopentane-1,3-diamine (CPDA) from hemicellulosic feedstock is established in this work. Through many explorations and optimizations, the single successful multi-step synthesis was found to comprise: (1) the Piancatelli rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone (4-HCP), (2) a highly improved isomerization of 4-HCP into cyclopentane-1,3-dione (CPDO) using the Ru Shvo catalyst, (3) conversion of CPDO into cyclopentane-1,3-dioxime (CPDX), and (4) a mild oxime hydrogenation of CPDX over Rh/C to afford the desired CPDA. In addition, diastereomerically pure cis- and trans-isomers of CPDA were reacted with (A) bio-based lactones, and (B) 5-(hydroxymethyl)furfural (HMF) to synthesize novel bifunctional diol monomers with internal amide and imine groups, respectively. Monomer 5, derived using γ-valerolactone (GVL), was successfully applied in the synthesis of polyurethanes.