Enantioselective Synthesis of Spiro Heterocyclic Compounds Using a Combination of Organocatalysis and Transition-Metal Catalysis.

Over the last ten years, the combination of organocatalysis with transition metal (TM) catalysis has become one of the most important toolboxes used for synthesizing optically pure compounds containing chiral quaternary centers, including spiro heterocyclic molecules. The dominant method in the enantioselective synthesis of spiro heterocyclic compounds based on synergistic catalysis includes chiral aminocatalysis and NHC catalysis, as already established covalent organocatalytic strategies. Another area of organocatalysis widely combined with TM catalysis producing enantiomerically enriched spiro heterocyclic compounds is non-covalent catalysis, dominated by chiral phosphoric acids, thiourea, and squaramide derivatives. This review article aims to summarize enantioselective methods used for constructing spirocyclic heterocycles based on a combination of organocatalysis and transition metal catalysis.

Enantioselective Construction of Chiral Bispiro[Oxindole-Pyrrolidine-Pyrazolone] Derivatives via Sequential and One-Pot Mannich/Hydroamination Reaction.

The atom-economic method for the preparation of novel bispirocyclic compounds containing three fused heterocyclic scaffolds privileged in drug discovery was developed by using a chiral amine-squaramide Mannich reaction and Au(I)-catalyzed hydroamination. The developed synthetic strategy performed either stepwise or as a one-pot process allows the formation of chiral bispirocyclic [oxindole-pyrrolidine-pyrazolones] in high yields (up to 75%) with excellent enantioselectivities (up to 99%).

Highly enantioselective addition of sulfur-containing heterocycles to isatin-derived ketimines.

In this study, we report a highly stereoselective addition of sulfur-containing heterocyclic compounds to isatin-derived ketimines efficiently catalyzed by cinchonidine-derived bifunctional tertiary aminothiourea (1 mol%). This organocatalytic methodology furnishes a new type of optically active heterocyclic compound with two adjacent chiral quaternary carbon stereocenters in good yield (up to 98%), with excellent diastereoselectivity (up to 20 : 1 dr) and high enantioselectivity (up to 95% ee).

Is Central Europe Safe from Environmental Lead Intoxications? A Case Series.

Preventive measures in Central Europe were successful in suppressing both occupational and environmental lead exposure so that they did not constitute a severe public health problem. However, rare lead intoxications still appear. We report on lead intoxication in four family members where the source was removed lead ceiling paint. The symptoms of the lead intoxication started several weeks after removal and the inhalational exposure to the minimum dust residues lasted for more than three months before the poisoning was diagnosed. Father developed anaemia and saturnine colics. He and his two daughters received antidotal treatment which had to be repeated in the children. Finally, all recovered completely.Lead intoxication may be easily overlooked due to the unspecific symptoms. It is necessary to think of this rare poisoning which may be caused by old paints, historical ceramics and lead shots, in addition to commercial products imported from abroad.

Unintentional Pharmaceutical-Related Medication Errors Caused by Laypersons Reported to the Toxicological Information Centre in the Czech Republic.

The purpose of the article was to study unintentional pharmaceutical-related poisonings committed by laypersons that were reported to the Toxicological Information Centre in the Czech Republic. Identifying frequency, sources, reasons and consequences of the medication errors in laypersons could help to reduce the overall rate of medication errors. Records of medication error enquiries from 2013 to 2014 were extracted from the electronic database, and the following variables were reviewed: drug class, dosage form, dose, age of the subject, cause of the error, time interval from ingestion to the call, symptoms, prognosis at the time of the call and first aid recommended. Of the calls, 1354 met the inclusion criteria. Among them, central nervous system-affecting drugs (23.6%), respiratory drugs (18.5%) and alimentary drugs (16.2%) were the most common drug classes involved in the medication errors. The highest proportion of the patients was in the youngest age subgroup 0-5 year-old (46%). The reasons for the medication errors involved the leaflet misinterpretation and mistaken dose (53.6%), mixing up medications (19.2%), attempting to reduce pain with repeated doses (6.4%), erroneous routes of administration (2.2%), psychiatric/elderly patients (2.7%), others (9.0%) or unknown (6.9%). A high proportion of children among the patients may be due to the fact that children's dosages for many drugs vary by their weight, and more medications come in a variety of concentrations. Most overdoses could be prevented by safer labelling, proper cap closure systems for liquid products and medication reconciliation by both physicians and pharmacists.

U0126, a mitogen-activated protein kinase kinase 1 and 2 (MEK1 and 2) inhibitor, selectively up-regulates main isoforms of CYP3A subfamily via a pregnane X receptor (PXR) in HepG2 cells.

Hepatocyte tumor cell lines lack the expression or induction properties of major cytochrome P450 (CYP) enzymes compared to primary human hepatocytes. The Ras/Raf/MEK/ERK signaling cascade contributes to hepatocarcinogenesis, dedifferentiation and loss of hepatocyte drug metabolism in hepatocyte tumors. In the present study, we examined whether MEK1/2 inhibitors can restore the expression of CYP genes in hepatocarcinoma HepG2 cells. We found that U0126, a prototype dual MEK1/2 inhibitor, is a potent inducer of CYP3A4, CYP3A5 and CYP3A7 mRNA expression (>100-fold) in HepG2 cells and CYP3A4 mRNA expression in primary human hepatocytes. This U0126-mediated induction is sensitive to the transcriptional inhibitor actinomycin D and was not detected for CYP2B6 or MDR1 mRNA expression. In gene reporter assays, U0126 activates a CYP3A4 promoter luciferase reporter construct containing PXR response elements (PXREs), but not a construct containing mutated PXREs. Based on a ligand binding assay and the examination of a PXR mutant expressing an obstructed ligand binding pocket, we found that U0126 is a ligand of PXR. We also found that U0126 up-regulates the mRNA expression of the nuclear receptors HNF4α, CAR, VDR and PXR but abolishes small heterodimer partner (SHP) corepressor expression in HepG2 cells. The MEK1/2 inhibitors PD0325901 and PD184352, as well as dominant-negative MEK1 expression, also down-regulate SHP mRNA expression. In contrast, dominant-negative MEK1 expression does not significantly induce CYP3A4 gene in HepG2 cells. In conclusion, we found that U0126 is an atypical PXR ligand that via direct (binding and activation of PXR) and indirect (SHP dowregulation) mechanisms selectively restores CYP3A genes in HepG2 cells.

Paracetamol poisonings in the Czech and Slovak Republic and N-acetylcysteine treatment. Data analysis.

OBJECTIVES: Paracetamol overdose belongs to frequent calls to Toxicological Information Centre (TIC) in the Czech Republic and to the National Toxicological Information Centre (NTIC) in Slovakia. The aim of the study was to evaluate outcomes and side effects of paracetamol overdose in both countries. METHODS: Data concerning paracetamol poisoning extracted from TIC and NTIC databases 2000-2013 and discharge reports were analysed. Numbers and outcomes in patients presenting within 24 hours of a single paracetamol overdose were compared in relation to 3 paracetamol concentration bands (≤ 100 mg/l, 100-149 mg/l, and 150 mg/l). RESULTS: 5397 inquiries concerning paracetamol were recorded in TIS and NTIC. Data from 196 discharge reports with plasma level were studied. Median age of the patients was 18 (0.2-86) years. Eight/196 (4.1%) patients developed side effects after N-acetylcysteine (NAC) administration. 120 cases fulfilled time criteria of the study and were divided into 3 groups, where 55.7%, 73.1% and 96.9% patients have been treated with NAC. Among these 120 patients, favourable outcome was seen in 100%, 100%, and 92.8%, respectively. One death due to suicidal attempt with plasma level 407 mg/l presenting at 20 hours has been recorded among 120 patients. No patient without NAC treatment died due to acute overdose and plasma concentration ≤ 150 mg/I at 4 hours. CONCLUSIONS: These data support the opinion that NAC should not be used in patients with < 149 mg/l levels in absence of higher risk factors because of very low risk of hepatotoxicity on one side, and side effects on the other side.

Trends in CNS affecting drugs in the calls to the Toxicological Information Center from 1997 to 2012.

OBJECTIVES: To analyze the number and trends in calls to the Toxicological Information Center (TIC) concerning pharmaceutical poisoning retrospectively during the past 15 years and to compare selected characteristics of the poisonings. DESIGN: Inquiries arising from drug poisonings in the years 1997-2012 were extracted and evaluated from the Czech database recording the consultations of TIC specialists. In addition, their cause, severity and dose evaluation (data electronically collected after 2005) were compared in the years 2005-2012 using standard statistical methods. RESULTS: During 15 years total 152,649 calls due to all types of potentially toxic agents were recorded in the TIC database. Central nervous system (CNS) affecting drugs represented 39.8% of calls due to all pharmaceutical poisonings. The proportion of adults was 72.2% and women comprised 64.4% of all patients. Whereas the number of calls caused by poisoning with tricyclic antidepressants (TCAs) and barbiturates decreased (by 366.7% and 340%, respectively), the calls due to selective serotonin reuptake inhibitors (SSRIs) and benzodiazepines overdose increased (by 1347.4% and 359.8%). The dose of CNS affecting drugs in 2005-2012 was considered lethal in 14.6% of the inquiries due to barbiturates and 8.6% due to TCAs, but only in 1.6% calls due to SSRIs and 0.5% of benzodiazepines. The highest percentage of medications errors was found during the treatment with barbiturates (16.4%). CONCLUSIONS: The current drugs prescription with improved safety profiles brings the beneficial effect of lowering the severity of poisonings and better prognosis of intoxications as observed in the TIC statistics.