Functionalization of polyesters with multiple B vitamins

A method to covalently attach combinations of six different B vitamins provided an avenue to new functional thermosets without multi‐step coupling reactions. The melt polymerization strategy required no organic solvent and facilitated covalent attachment of OH (B₁, B₂, B₅, B₆) or COOH (B₇, B₉) groups on B vitamins via Fischer esterification. Characterization of model reactions with LC/MS, FTIR, and GPC confirmed covalent attachment. Based on control experiments, B vitamins demonstrated unexpected thermal stability and appreciable solubility in the melt polymerization. This approach was demonstrated with citric acid and diglycerol, but has wide‐ranging potential for other polar monomers with negative octanol–water partition coefficients (LogP). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3308–3316     

Incorporation of nonmethyl branches by isoprenoid-like logic: multiple beta-alkylation events in the biosynthesis of myxovirescin A1

Several polyketide secondary metabolites are predicted to undergo isoprenoid-like beta-alkylations during biosynthesis. One such secondary metabolite is myxovirescin A1, produced by Myxococcus xanthus. Myxovirescin is of special interest in that it appears to undergo two distinct beta-alkylations. Additionally, the myxovirescin biosynthetic gene cluster lacks tandem thiolation domains required in the synthesis of other beta-branched secondary metabolites. To probe the origins of the beta-branches in myxovirescin, we heterologously overexpressed the proteins predicted to be responsible for myxovirescin beta-alkylation and reconstituted their activities in vitro on model substrates. Our results confirm that myxovirescin undergoes two isoprenoid-like beta-alkylations during its biosynthesis, including an unprecedented beta-ethylation. The study of its biosynthesis should shed light on the scope and requirements for isoprenoid-like biosynthetic logic in a polyketide context.