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The photophysical and mechanicalproperties of novel poly(carbonate-amide)sderived from two biorenewable resources, ferulic acid (FA) and l-tyrosine ethyl ester, were evaluated in detail. From thesetwo bio-based precursors, a series of four monomers were generated(having amide and/or carbonate coupling units with remaining functionalitiesto allow for carbonate formation) and transformed to a series of fourpoly(carbonate-amide)s. The simplest monomer, which was biphenolicand was obtained in a single amidation synthetic step, displayed bright,visible fluorescence that was twice brighter than FA. Multidimensionalfluorescence spectroscopy of the polymers in solution highlightedthe strong influence that regioselectivity and the degree of polymerizationhave on their photophysical properties. The regiochemistry of thesystem had little effect on the wettability, surface free energy,and Young’s modulus (ca. 2.5 GPa) in the solid state. Confocalimaging of solvent-cast films of each polymer revealed microscopicallyflat surfaces with fluorescent emission deep into the visible region.Fortuitously, one of the two regiorandom polymers (obtainable fromthe biphenolic monomer in only an overall two synthetic steps fromFA and l-tyrosine ethyl ester) displayed the most promisingfluorescent properties both in the solid state and in solution, allowingfor the possibility of translating this system as a self-reportingor imaging agent in future applications. To further evaluate the potentialof this polymer as a biodegradable material, hydrolytic degradationstudies at different pH values and temperatures were investigated.Additionally, the antioxidant properties of the degradation productsof this polymer were compared with its biphenolic monomer and FA. [ABSTRACT FROM AUTHOR]

Ferulic acid (FA), a bio-based resourcefound in fruits and vegetables,was coupled with a hydroxyl-amino acid to generate a new class ofmonomers to afford poly(carbonate–amide)s with potential todegrade into natural products. l-Serine was first selectedas the hydroxyl-amino partner for FA, from which the activated p-nitrophenyl carbonate monomer was synthesized. Unfortunately,polymerizations were unsuccessful, and the elimination product wassystematically obtained. To avoid elimination, we revised our strategyand used l-tyrosine ethyl ester, which lacks an acidic protonon the α position of the ethyl ester. Four new monomers weresynthesized and converted into the corresponding poly(carbonate–amide)swith specific regioselectivities. The polymers were fully characterizedthrough thermal and spectroscopic analyses. Preliminary fluorescentstudies revealed interesting photophysical properties for the monomersand their corresponding poly(carbonate–amide)s, beyond thefluorescence characteristics of l-tyrosine and FA, makingthese materials potentially viable for sensing and/or imaging applications,in addition to their attractiveness as engineering materials derivedfrom renewable resources. [ABSTRACT FROM AUTHOR]

The structure and properties of β-thiolactones (2-thietanones) are discussed with an emphasis on the differences with β-lactones. Methods for the synthesis of β-thiolactones are reviewed as are the reactions of this relatively little explored class of sulfur-based hetereocycles. Finally, the biology of β-thiolactones is reviewed. [ABSTRACT FROM PUBLISHER]

An investigation into the comparative reactivity of simple β-lactones and β-thiolactones toward a thiol and a primary amine is reported. A simple 3-mercaptomethyl-2-oxetanone is found to undergo rearrangement in the presence of aqueous base to give the corresponding thietane-3-carboxylic acid rather than the 3-hydroxymethyl-2-thietanone. Implications for the use of β-thiolactones in bioorganic and medicinal chemistry are discussed.