A one light strand: 2′‐Deoxyguanosine was made fluorescent by attaching a vinyl group at the C8 position (see structure). The resulting fluorophore is highly sensitive towards DNA double‐strand formation and alterations in the secondary structure of its parent oligonucleotide, such as formation of different quadruplex structures. These differences can be readily detected in the emission spectrum (see picture).

A number of 2-phenylindole derivatives with one hydroxy group in the meta or para position of the phenyl ring and a second one in position 5, 6, or 7 of the indole nucleus were synthesized. In addition, different alkyl groups were introduced into positions 1 and 3 of the heterocycle. The influence of these structural variations on the binding affinity for the calf uterine estrogen receptor was studied. A prerequisite for the binding is the presence of an alkyl group at the nitrogen. Favorable are a hydroxy group located in the para position of the phenyl ring and short alkyl chains both in position 1 and 3 of the indole. The highest relative binding affinity (RBA) values (e.g., 33 for 20b, 21 for 24b, 23 for 35b) are close to that of hexestrol (RBA = 25, estradiol = 100). Depending on the positions of the oxygen functions and size of the alkyl residues, the indole derivatives behaved as strong estrogens (20c, 24c, 35c) or impeded estrogens with antagonistic activity (23c, 29c, 30c, 31c, 40c, 44c) in the immature mouse. Some of these derivatives (20c, 23c, 24c, 29c, 30c, 31c) were tested for their inhibitory effect on dimethylbenzanthracene-induced hormone-dependent mammary tumors of the rat. Both types exhibited a strong growth inhibition with a reduction of the average tumor area at appropriate dosage. A mode of action involving the estrogen receptor system is assumed.

Differences in transporter expression in Caco-2 cells compared with jejunal tissue, as well as expression dependence on culture time must be considered in in vitro studies to avoid under- or overestimation of certain transporters. The Caco-2 cell model is not suitable for the evaluation of DDIs caused by transporter induction. Copyright © 2016 John Wiley & Sons, Ltd.

Hydroxy-2-phenylindoles carrying substituted benzyl groups and similar substituents at the nitrogen were synthesized and tested for their ability to displace estradiol from its receptor. All of the derivatives tested exhibited high binding affinities for the calf uterine estrogen receptor, with RBA values ranging from 0.55 to 16 (estradiol 100). The mouse uterine weight tested revealed only low estrogenicity for this class of compounds. Several derivatives showed antiestrogenic activity with a maximum inhibition of estrone-stimulated uterine growth of 40%. Two of the compounds (6c, 21c) were tested for antitumor activity in dimethylbenanthracene- (DMBA-) induced estrogen-dependent rat mammary tumors. Only the 4-cyanobenzyl derivative 21c was active. After 4 weeks of treatment with 12 mg/kg (6 times/week), the average tumor area was decreased by 57% (control +204%). In vitro, an inhibitory effect of 21b was only observed with hormone-sensitive MCF-7 breast cancer cells but not with hormone-independent MDA-MB 231 cells. These results make a mode of action involving the estrogen receptor system likely.

Attachment of a vinyl group at guanine position 8 provides fluorescent properties of the nucleobase. Therefore, 8-vinylguanine was introduced as a 2-aminoethylglycine peptide nucleic acid (PNA) building block. Incorporation of the guanine analog in short PNA sequences by Fmoc solid phase peptide synthesis allowed the differentiation between hybridization states of specific double strands with DNA, RNA, and PNA as well as quadruplex forming RNA/PNA oligomers based on fluorescence intensity.