On the inhibition of HIV-1 protease by hydrazino-ureas displaying the N-->C=O interaction.

To create novel HIV-1 protease (HIV PR) inhibitors, we have extended our investigations of the N-->C=O interaction as a moiety that reproduces electrostatic properties of the transition state of peptidolysis. Consequently, we prepared a series of compounds with an unusual hydrazino-urea core. In polar protic media, these adopt solely a cyclic constitution displaying the interaction on one side of the molecule while offering a urea moiety on the opposite side meant to hydrogen-bond with the enzyme flaps. Each inhibitor candidate was obtained via a key series of three synthetic steps employing carbonyl-di-imidazole (CDI). It was thus possible to efficiently fuse two independent building blocks, a hydrazine and a protected aminoaldehyde in a convergent manner. NMR and UV analysis proved that all compounds, when dissolved in polar protic media, existed exclusively in the cyclic constitution exhibiting the N-->C=O interaction. In total, five inhibitor candidates were tested with HIV PR for their potency. The one carrying the least bulk in peripheral substituents showed the highest activity. Its very low molecular weight (365 g/mol) holds great promise for future improvements in affinity without violating Lipinski's rule of remaining within the limit of 500 g/mol.

[Inpatient Mental Health Care without Mechanical Restraint, Seclusion or Compulsory Medication]. / Auf Fixierungen kann in der klinischen Praxis verzichtet werden ­ ohne dass auf Zwangsmedikation oder Isolierungen zurückgegriffen wird.

Mechanical restraint is a common occurance in Germany's mental health care facilities; less common though not unusual are seclusion and compulsory medication. The authors describe a model to calculate additional resources required to provide mental health care without any of these forms of coercive measures. An analysis of actual clinical situations that led to mechanical restraint provides information of the 1:1, 2:1 or 3:1 intensive support necessary to cope with crises in inpatient mental health care. The additional resources required to provide inpatient mental health care without mechanical restraint, seclusion or compulsory medication would be at 4 % of the annual hospital budget. A national shortage of skilled nursing staff appears to be a limiting factor in moving towards a human-rights based mental health care.

Diversity-oriented synthesis of a drug-like system displaying the distinctive N-->C=O interaction.

This study describes the syntheses and characterization of two hydrazino ureas. These fold into a six-membered ring by virtue of the infrequently observed (delta+)N-->C=O (delta-) interaction when solvated by polar protic media. The highly polar functional group resulting from this interaction is hypothesized to especially reproduce electronic but also steric features of the transition states of peptide hydrolysis. The urea moiety constitutes an additional key element of modern HIV-1 protease (HIV PR) inhibitors and is meant to interact with the enzyme flaps. We have developed an efficient, convergent synthetic route to enantiopure compounds that uses CDI to couple two independent building blocks, one derived from amino acids and the other one from easily accessible hydrazines. It is thus amenable to rapid generation of diversity in order to screen for novel HIV PR inhibitors. A complete study using one- and two-dimensional NMR as well as UV spectroscopy confirmed the sole existence of the cyclic constitution of target compounds 7 and 8 in methanol. Total reversal to the linear aldehydic form is observed upon passage to apolar media.

Screen-printed bienzymatic sensor based on sol-gel immobilized Nippostrongylusbrasiliensis acetylcholinesterase and a cytochrome P450 BM-3 (CYP102-A1) mutant.

Here, we describe the development of a bi-enzymatic biosensor that simplifies the sample pretreatment steps for insecticide detection, and opens the way for a highly sensitive detection of phosphorothionates in food. These compounds evolve their inhibitory activity towards acetylcholinesterases (AChEs) only after oxidation, which is performed in vivo by P450 monooxygenases. Consequently, phosphorothionates require a suitable sample pretreatment by selective oxidation to be detectable in AChE based systems. In this study, enzymatic phosphorothionate activation and AChE inhibition were integrated in a single biosensor unit. A triple mutant of cytochrome P450 BM-3 (CYP 102-A1) and Nippostrongylus brasiliensis AChE (NbAChE) was immobilized using a fluoride catalyzed sol-gel process. Different sol-gel types were fabricated and characterized regarding enzyme loading capacity and enzyme activity containment. The enzyme sol-gel itself already proved to be suitable for the highly sensitive detection of paraoxon and parathion in a spectrometric assay. A method for screen-printing of this enzyme sol-gel on thick film electrodes was developed. Finally, amperometric biosensors containing coimmobilized NbAChE and the cytochrome P450 BM-3 mutant were produced and characterized with respect to signal stability, organophosphate detection, and storage stability. The detection limits achieved were 1 microg/L for paraoxon and 10 microg/L for parathion, which is according to EC regulations the highest tolerable pesticide concentration in infant food.

Desymmetrizations of meso-tert-norbornenols by rhodium(I)-catalyzed enantioselective retro-allylations.

Rhodium-catalyzed desymmetrizations of meso-tert-norbornenols by retro-allylations generate allyl-rhodium species that allow for a rich and diverse downstream reactivity.

Bibenzyl- and stilbene-core compounds with non-polar linker atom substituents as selective ligands for estrogen receptor beta.

A series of structurally simple bibenzyl-diol and stilbene-diol core molecules, structural analogs of the well-known hexestrol and diethylstilbestrol non-steroidal estrogens, were prepared and evaluated as estrogen receptor (ER) subtype-selective ligands. Analysis of their ERalpha and ERbeta binding showed that certain substitution patterns engendered binding affinities that were >100-fold selective for ERbeta. When further investigated in cell-based gene transcription assays, some molecules showed similarly high relative transcriptional potency selectivity in favor of ERbeta. Interestingly, the most ERbeta-selective molecules were those bearing non-polar substituents on one of the internal carbon atoms. These compounds should be useful probes for determining the physiological roles of ERbeta, and they might lead to the development of more selective and thus safer pharmaceuticals.

Phenethyl pyridines with non-polar internal substituents as selective ligands for estrogen receptor beta.

To create estrogen receptor beta (ERbeta)-selective ligands with improved biological characteristics, we have extended our investigations of structurally simple bibenzyl-core ligands by preparing a series of compounds in which one phenol is replaced by a 3-hydroxypyridine ring. These phenethyl pyridines were obtained by picoline anion alkylation, and compounds with different patterns of alkyl substitution on the central two carbon units were prepared. Binding affinities for ERalpha and ERbeta were determined, and ligands with promising affinities and selectivities for ERbeta were further tested for their gene transcriptional activity. Several compounds had high affinity selectivity and good potency selectivity in transcription assays. This study advances our understanding of compounds having ER-subtype selectivity and will help to direct efforts in developing novel ER ligands.

Isocoumarins as estrogen receptor beta selective ligands: Isomers of isoflavone phytoestrogens and their metabolites.

In a search for new ligands selective for the estrogen receptor beta (ERbeta), we prepared a series of non-steroidal compounds having an isocoumarin core structure. An interesting feature of these derivatives is that they bear the same functionalities as the well-known ERbeta -selective, isoflavone phytoestrogens daidzein and genistein, but in an isomeric arrangement. These compounds could be prepared efficiently by electrophilic cyclization of acetylenic ester precursors, followed by simple manipulations to introduce additional substituents. Through a reduction of some of the isocoumarins, we also obtained isomeric analogs of the isoflavone metabolites equol and dehydroequol. The compounds we prepared were evaluated in ER binding assays, and selected compounds were studied further in cell-based gene transcription assays. Several of the isocoumarins and their analogs are high-affinity ligands that show considerable selectivity for ERbeta in terms of binding affinity, and strikingly high ERbeta selectivity in terms of potency in gene transcription assays. Two of the best compounds, which combine high transcriptional potency with an ERbeta selectivity greater than 1000, should prove to be excellent probes of ERbeta function in vivo.