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SummaryA library of ten 1,3-diyne-linked peptoids has been synthesized through an Ugi four-component reaction (U-4CR) followed by a copper-catalysed alkyne homocoupling (Glaser reaction). The short and chemoselective reaction sequence allows generating diverse (pseudo) dimeric peptoids. A combinatorial version allows the one-pot preparation of, e.g., six-compound-libraries of homo- and heterodimers verified by ESI-MS and HPLC. In a preliminary evaluation, some compounds display moderate activity against the Gram-positive bacterium Bacillus subtilis.

Rational re-design of the substrate pocket of phenylpropanoidflavonoid O-methyltransferase (PFOMT) from Mesembryanthemum crystallinum, an enzyme that selectively methylates the 3'position (= meta-position) in catechol-moieties of flavonoids to guiacol-moieties, provided the basis for the generation of variants with opposite, i. e. 4'-(para-) regioselectivity and enhanced catalytic efficiency. A double variant (Y51R/N202W) identified through a newly developed colorimetric assay efficiently modified the para-position in flavanone and flavanonol substrates, providing access to the sweetener molecule hesperetin and other rare plant flavonoids having an isovanilloid motif.

A series of prevailing prenylated furanocoumarins from leaves of Dorstenia gigas and Dorstenia foetida (Moraceae) were investigated by liquid chromatography/electrospray tandem mass spectrometry. The mass spectral behavior of the furanocoumarins under positive ion electrospray conditions is discussed using both an ion trap and a triple quadrupole system. It is demonstrated that both methods represent valuable tools not only for the rapid classification of this type of compounds, but also with respect to their substitution pattern.