Versatile Preparation of Fluorescent Particles Based on Polyphosphazenes: From Micro- to Nanoscale

A series of intrinsically fluorescent hydrophobic and amphiphilic polyphosphazenes with ethyl tryptophan (EtTrp) and poly(N-isopropylacrylamide) (PNIPAAm) or poly(ethylene glycol) (PEG) as hydrophobic and hydrophilic segments, respectively, are synthesized. Depending on polymer composition and preparation procedure, particles with diameters ranging from micro- to nanoscale can be prepared successfully, which might be used as a visible tracer, both in 14vitro or in 14vivo, in drug- or gene-delivery systems, as well as in other biomedical studies such as diagnostic medicine and brain research. Most importantly, in combination with the flexible synthesis and versatile modification of polyphosphazene, this method provides a general protocol to engineer a broad range of fluorescent particles with different properties based on diverse polymers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57545/1/2081_ftp.pd

Synthesis of the fungal natural product (-)-xylariamide A

The first synthesis of the fungal natural product (-)-xylariamide A 1 is reported. N,O-bis(trimethylsilyl)acetamide induced coupling of D-tyrosine with (E)-but-2-enedioic acid 2,5-dioxo-pyrrolidin-1-yl ester methyl ester 5 produced the dechloro natural product 6, which was subsequently monochlorinated using oxone and KCl to yield synthetic 1. (-)-Xylariamide A 1, (+)-xylariamide A 2 and (-)-dechloroxylariamide A 6 displayed no cytotoxic or antimicrobial activity