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The total synthesis of iromycin, a microbial metabolite conducted by using a flexible and highly convergent approach demonstrated its interesting biological activity as a NO synthase inhibitor.

The synthesis of functionalized 2-alkyl-idenepyrrolidines and pyrroles by the reaction of 1,3-bis-silyl enol ethers with 2-azido-1,1-dimethoxyethane and subsequent Staudinger-aza-Witting reaction is reported. The condensation of 1,3-dicarbonyl dianions with [alpha]-azidoketones afforded open-chained condensation products that were transformed into pyrroles by dreactions and the subsequent treatment with trifluoroacetic acid.

Treatment of γ-azido-β-hydroxyketones with triphenylphosphine resulted, depending on the structural features of the starting materials, in a domino "Staudinger/semi-aza-Wittig/fragmentation" reaction rather than a normal aza-Wittig reaction. 2-Azido-1-hydroxy-1-(2,4-dioxoalkyl)cyclopentanes, readily available by condensation of 1,3-dicarbonyl dianions with 2-azidocyclopentanone, proved to be optimal starting materials for these reactions which afforded 1-(1,3-dioxoalkyl)amino-2-(alkylidene)cyclopentanes. [ABSTRACT FROM AUTHOR]

Hydroxylated rhodamines, carbopyronines, silico- and germanorhodamines with absorption maxima in the range of 530-640 nm were prepared and applied in specific labeling of living cells. The direct and high-yielding entry to germa- and silaxanthones tolerates the presence of protected heteroatoms and may be considered for the syntheses of various sila- and germafluoresceins, as well as -rhodols. Application in stimulated emission depletion (STED) fluorescence microscopy revealed a resolution of 50-75 nm in one- and two-color imaging of vimentin-HaloTag fused protein and native tubulin. The established structure-property relationships allow for prediction of the spectral properties and the positions of spirolactone/zwitterion equilibria for the new analogues of rhodamines, carbo-, silico-, and germanorhodamines using simple additive schemes., (© 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Reversibly photoswitchable 1,2-bis(2-ethyl-6-phenyl-1-benzothiophene-1,1-dioxide-3-yl)perfluorocyclopentenes (EBT) having fluorescent "closed" forms were decorated with four or eight carboxylic groups and attached to antibodies. Low aggregation, efficient photoswitching in aqueous buffers, specific staining of cellular structures, and good photophysical properties were demonstrated. Alternating light pulses of UV and blue light induce numerous reversible photochemical transformations between two stables states with distinct structures. Using relatively low light intensities, EBTs were applied in biology-related super-resolution microscopy based on the reversible saturable (switchable) optical linear fluorescence transitions (RESOLFT) and demonstrated optical resolution of 75 nm., (© 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)