Hydrogels are superior wound dressings because they can provide protection and hydration of the wound, as well as the controlled release of therapeutic substances to aid tissue regeneration and the healing process. Hydrogels obtained from natural precursors are preferred because of their low cost, biocompatibility, and biodegradability. We describe the synthesis of novel functional hydrogels based on two natural products—citric acid (CA) and pentane-1,2,5-triol (PT, a product from lignocellulose processing) and poly(ethylene glycol) (PEG-600)—via an environment friendly approach. The hydrogels were prepared via monomer crosslinking through a polycondensation reaction at an elevated temperature in the absence of any solvent. The reagents were blended at three different compositions with molar ratios of hydroxyl (from PT and PEG) to carboxyl (from CA) groups of 1:1, 1:1.4, and 1.4:1, respectively. The effect of the composition on the physicomechanical properties of materials was investigated. All hydrogels exhibited pH-sensitive behavior, while the swelling degree and elastic modulus were dependent on the composition of the polymer network. The proteolytic enzyme serratiopeptidase (SER) was loaded into a hydrogel via physical absorption as a model drug. The release profile of SER and the effects of the enzyme on healthy skin cells were assessed. The results showed that the hydrogel carrier could provide the complete release of the loaded enzyme.

In this study, as a product from the efficient Achmatowicz rearrangement and mild subsequent hydrogenation–reduction reactions of biorenewable C5 alcohols derived from lignocellulose, pentane-1,2,5-triol was successfully used after oxypropylation in the preparation of rigid polyurethane foams—one of the most important classes of polymeric materials. Despite the broad range of applications, the production of polyurethanes is still highly dependent on petrochemical materials considering the need of renewable raw materials and new process technologies for the production of polyol or isocyanate components as a key point for the sustainable development of polyurethane foams. The synthesized oxypropylated pentane-1,2,5-triol was analyzed using proton NMR spectroscopy, hydroxyl number, and viscosity, whereas the newly obtained foams incorporated with up to 30% biorenewable polyol were characterized using compressive stress, thermogravimetry, dynamic mechanical analysis, and scanning electron microscopy. The modified rigid polyurethanes showed better compressive strength (>400.0 kPa), a comparable thermal degradation range at 325–450 °C, and similar morphological properties to those of commercial polyurethane formulations.

Enantiomerically pure (S)-1-phenylethan-1-amine has been applied in Mannich-type condensation between formaldehyde and naphthalenediols leading to the synthesis of chiral bis-dihydro[1,3]naphthoxazines in excellent yields. Salen-type structures have been synthesized, applying R,R- or S,S-cyclohexane-1,2-diamines in condensation with formaldehyde and naphthalene-2-ol. The obtained chiral imidazolidine derivatives of the type 1,1′-(((3a,7a)-hexahydro-1H-benzo[d]imidazole-1,3(2H)diyl)bis(methylene))bis(naphthalen-2-ol) were evaluated as pre-catalysts for the addition of diethyl zinc to aldehydes. The structures of the newly synthesized compounds were elucidated using ¹D and ²D NMR experiments (COSY, HMBC, HSQS), elemental analysis, mass spectrometry (HRMS spectra) and single-crystal X-ray diffraction (SCXRD). The products were further characterized with powder X-ray diffraction (PXRD) and thermal analysis (DSC).