Metal and catalyst‐free carbohydroxylations and carboetherifications at room temperature have been achieved by a combination of beneficial factors including high aryl diazonium concentration and visible light irradiation. The acceleration of the reaction by visible light irradiation is particularly remarkable against the background that neither the aryldiazonium salt nor the alkene show absorptions in the respective range of wavelength. These observations point to weak charge transfer interactions between diazonium salt and alkene, which are nevertheless able to considerably influence the reaction course. As highly promising perspective, many more aryldiazonium‐based radical arylations might benefit from simple light irradiation without requiring a photocatalyst or particular additive.

Functionalizations of arenes and alkenes via additive-free radical reactions using highly photosensitive, fluorescein-derived diazonium salts are described. The particular properties of the diazonium salts enable unique Meerwein-type carbohydroxylations of non-activated alkenes, which can be rationalized by a reaction mechanism involving forth and back electron transfer from and to the xanthene subunit of the fluorescein moiety.

Endogenous biomarkers are discussed as tools for detection of drug‐drug interactions mediated by renal transport proteins, such as organic cation transporter 2 (OCT2), multidrug and toxin extrusion proteins (MATE1 and MATE2‐K) and organic anion transporters (OAT1 and OAT3). Whereas sensitivity of some endogenous biomarkers against at least one clinical transporter inhibitor has frequently been shown, intrastudy comparisons of the extent of effects of inhibitors on different biomarkers are frequently lacking. Moreover, in vivo specificity of such discussed biomarkers has frequently not been studied. We therefore investigated changes of ten previously described putative biomarkers for inhibition of OCT2/MATEs, as well as 15 previously described putative biomarkers for OATs in human plasma and urine samples of healthy volunteers in response to treatment with four inhibitors of transport proteins [verapamil (P‐glycoprotein), rifampin (organic anion transporting polypeptides), cimetidine (OCT2/MATEs), and probenecid (OATs)]. Two of the putative biomarkers had been suggested for both OCT2/MATEs and OATs. All substances were unequivocally identified in an untargeted metabolomics assay. The OCT2/MATE biomarkers choline and trimethylamine N‐oxide were both sensitive and specific (median log2‐fold changes ‐1.18 in estimated renal elimination and ‐0.85 in urinary excretion, respectively). For renal OATs, indoleacetyl glutamine and indoleacetic acid (median log2‐fold changes ‐3.77 and ‐2.85 in estimated renal elimination, respectively) were the candidates for sensitive and specific biomarkers with the most extensive change, followed by taurine, indolelactic acid and hypoxanthine. This comprehensive study adds further knowledge on sensitivity and specificity of 23 previously described biomarkers of renal OCT2/MATE‐ and OAT‐mediated drug‐drug interactions.