Residues of chlorinated pesticides in mother\u27s milk and child\u27s serum

Uzorci mlijeka i seruma 27 hospitaliziranih dojilja iz Bjelovara i Zaboka s okolnim mjestima analizirani su na ostatke kloriranih insekticida aldrina, dieldrina, endrina, heptaklora, heptaklor epoksida, lindana i ostalih stereoizomera heksaklorcikloheksana, pp-\u27DDT-a i metabolita (pp-\u27DDE i pp-\u27DDD) i op-\u27DDT. Posebno je još analizirano 18 seruma majki i isto toliko seruma njihove djece koji su svi iz Zagreba. U uzorcima smo dokazali prisutnost samo Gama-HCH (Lindan). Alfa-HCH, pp-\u27DDE, op-\u27DDT, pp-\u27DDD i pp-\u27DDT. Koncentracije nađenih insekticida mnogo su veće u mlijeku dojilja nego u serumima. U serumima djece bilo je manje samo pp-\u27DDE i pp-\u27DDT nego u serumima njihovih majki. Uzorci seruma dojilja iz Zaboka i okolnih mjesta, hospitaliziranih u Zaboku i serumi dojilja iz Bjelovara hospitaliziranih u Zagrebu (N = 27) sadržavaju više navedenih insekticida nego uzorci seruma dojilja s područja Zagreba (N = 18).Milk samples obtained from 27 hospitalized lactating women and an equal number of sera from the same women were examined for residues of chlorinated hydrocarbon insecticides: aldrin, dieldrin, endrin, heptachlor, heptachlorepoxide, lindan and other steroisomers of hexachlorcyclohexane, pp\u27DDT and its metabolites (pp\u27-DDE, pp\u27-DDD) and op\u27-DDT. Additional 18 samples of mother\u27s sera and an equal number of their children\u27s sera were examined separately. The aim was to find out whether there is a correlation between the pesticide residues in mother\u27s serum and mother\u27s milk and in the serum of the mother and her child. The insecticides were determined according to the procedure used by the US Food and Drug Administration (4). Chlorinated hydrocarbon insecticides in the serum were examined with the method described by Wyllie and coworkers (5). In all samples only the presence of a-HCH, y-HCH, pp\u27-DDE, op\u27-DDT, pp\u27-DDD and pp\u27-DDT could be demonstrated. The concentration ratio between mother\u27s milk and serum was between 4 and 11. The concentration ratio between mother\u27s and child\u27s serum was below 1 except for pp\u27-DDE and pp\u27-DDT

Total Synthesis of a Reported Fluorometabolite from <i>Streptomyces</i> sp. TC1 Indicates an Incorrect Assignment. The Isolated Compound Did Not Contain Fluorine

3,5-Di-<i>tert-</i>butyl-4-fluorophenylpropionic acid (<b>1</b>) was recently reported as a natural product from <i>Streptomyces </i>sp<i>.</i> TC1. This was a notable disclosure because fluorinated natural products are exceedingly rare, and in this case it suggested that the bacterium had the capacity to mediate an enzymatic aryl fluorination reaction. However, a synthesis of the putative metabolite <b>1</b> demonstrates that the spectroscopic data are inconsistent with the proposed structure. There is no evidence that the isolated compound contained a fluorine atom

Synthesis of Homoleptic and Heteroleptic Bis-N-heterocylic Carbene Group 11 Complexes

A straightforward synthetic route has been developed permitting the formation of homoleptic and heteroleptic bis-N-heterocyclic carbene metal complexes. The methodology has proven efficient for all group 11 members. These complexes are easily synthesized using [M­(Cl)­(NHC)] with different NHC salts in the presence of inexpensive bases such as sodium hydroxide. These systems were fully characterized and displayed high stability even in the presence of light

Telescoped Synthesis of Stereodefined Pyrrolidines

Telescoped and one-pot olefination/asymmetric functionalization approaches to disubstituted pyrrolidines (dr up to 99:1, up to 99% ee) have been developed using commercially available tetramisole (0.1 to 5 mol %). Using OTMS-quinidine as the Lewis base gives preferential access to an <i>anti</i>-configured pyrrolidine in high enantioselectivity

Enantioselective Synthesis in Continuous Flow: Polymer-Supported Isothiourea-Catalyzed Enantioselective Michael Addition–Cyclization with α‑Azol-2-ylacetophenones

A packed reactor bed incorporating a polymer-supported isothiourea HyperBTM catalyst derivative has been used to promote the enantioselective synthesis of a range of heterocyclic products derived from α-azol-2-ylacetophenones and -acetamides combined with alkyl, aryl, and heterocyclic α,β-unsaturated homoanhydrides in continuous flow via an α,β-unsaturated acyl-ammonium intermediate. The products are generated in good to excellent yields and generally in excellent enantiopurity (up to 97:3 er). Scale-up is demonstrated on a 15 mmol scale, giving the heterocyclic product in 68% overall yield with 98:2 er after recrystallization

Zwitterionic Alkali-Metal Silanides of Tripodal Ligand Geometry: Synthesis, Structure, and Lewis Acid–Base Chemistry

A unique family of zwitterionic alkali-metal silanides of general formula [Si­(SiMe₂OR)₃M] (M-<b>3</b>), where M = Li, Na, K and R = CH₂CH₃ (M-<b>3b</b>), CH­(CH₃)₂ (M-<b>3c</b>), CH₂CH­(CH₃)₂ (M-<b>3d</b>), CH₂CH₂OSCH₃ (M-<b>3g</b>), CH₂CH₂N­(CH₃)₂ (M-<b>3h</b>), have been synthesized and their structures fully characterized. Compounds M-<b>3</b> were prepared from reactions of the corresponding alkali-metal alkoxides, R′OM (R′ = Bu^t, Buⁱ; M = Li, Na, K) with the silanes Si­(SiMe₂OR)₄ (<b>2a</b>–<b>h</b>), where R = CH₂CH₃ (<b>b</b>), CH­(CH₃)₂ (<b>c</b>), CH₂CH­(CH₃)₂ (<b>d</b>), CH₂CH₂OSCH₃ (<b>g</b>), CH₂CH₂N­(CH₃)₂ (<b>h</b>), via selective Si–Si bond cleavage. Analysis of the X-ray data of Li-<b>3a</b>–<b>e</b>,<b>g</b>, Li-<b>h</b>, Li-<b>4</b>, Na-<b>3a</b>–<b>c</b>,<b>e</b>,<b>f</b>,<b>h</b>, and K-<b>3b</b>,<b>d</b>,<b>e</b>,<b>g</b> revealed two major structural motifs in the solid state: infinite chain type and monomeric zwitterions. The reaction of Si­(SiMe₂OCH₂CH₃)₃Li (Li-<b>3b</b>) with BPh₃ in THF gave the zwitterionic Lewis acid–base complex Ph₃BSi­(SiMe₂OCH₂CH₃)₃Li·THF (Li-<b>5b</b>). Reactions of W­(CO)₆ with Li-<b>3b</b>–<b>d</b> and Na-<b>3b</b>,<b>c</b> resulted in the formation of the zwitterionic silyl tungstenate complexes (CO)₅WSi­[SiMe₂OCH₂CH₃]₃Li (Li-<b>6b</b>), (CO)₅WSi­[SiMe₂OCH­(CH₃)₂]₃Li (Li-<b>6c</b>), (CO)₅WSi­[SiMe₂OCH₂CH­(CH₃)₂)]₃Li (Li-<b>6d</b>), (CO)₅WSi­(SiMe₂OCH₂CH₃)₃Na (Na-<b>6b</b>), and (CO)₅WSi­[SiMe₂OCH­(CH₃)₂]₃Na (Na-<b>6c</b>), respectively. The solid-state structures of Li-<b>5b</b> and Na-<b>6b</b> were determined by X-ray crystallography

Modular Synthesis of Complex Benzoxaboraheterocycles through Chelation-Assisted Rh-Catalyzed [2 + 2 + 2] Cycloaddition

Benzoxaboraheterocycles (BOBs) are moieties of increasing interest in the pharmaceutical industry; however, the synthesis of these compounds is often difficult or impractical due to the sensitivity of the boron moiety, the requirement for metalation–borylation protocols, and lengthy syntheses. We report a straightforward, modular approach that enables access to complex examples of the BOB framework through a Rh-catalyzed [2 + 2 + 2] cycloaddition using MIDA-protected alkyne boronic acids. The key to the development of this methodology was overcoming the steric barrier to catalysis by leveraging chelation assistance. We show the utility of the method through synthesis of a broad range of BOB scaffolds, mechanistic information on the chelation effect, intramolecular alcohol-assisted BMIDA hydrolysis, and linear/cyclic BOB limits as well as comparative binding affinities of the product BOB frameworks for ribose-derived biomolecules

Orthogonal Recognition Processes Drive the Assembly and Replication of a [2]Rotaxane

Within a small, interconnected reaction network, orthogonal recognition processes drive the assembly and replication of a [2]­rotaxane. Rotaxane formation is governed by a central, hydrogen-bonding-mediated binding equilibrium between a macrocycle and a linear component, which associate to give a reactive pseudo­rotaxane. Both the pseudo­rotaxane and the linear component undergo irreversible, recognition-mediated 1,3-dipolar cycloaddition reactions with a stoppering maleimide group, forming rotaxane and thread, respectively. As a result of these orthogonal recognition-mediated processes, the rotaxane and thread can act as auto-catalytic templates for their own formation and also operate as cross-catalytic templates for each other. However, the interplay between the recognition and reaction processes in this reaction network results in the formation of undesirable pseudo­rotaxane complexes, causing thread formation to exceed rotaxane formation in the current experimental system. Nevertheless, in the absence of competitive macrocycle-binding sites, realization of a replicating network favoring formation of rotaxane is possible

Cationic Platinum(II) Complexes Bearing Aryl-BIAN Ligands: Synthesis and Structural and Optoelectronic Characterization

Five cationic platinum­(II) complexes bearing a 2-(3′-substituted aryl)­pyridine cyclometalating ligand (C^∧N) and a neutral Ar-BIAN ligand have been synthesized: [Pt­(ppy)­(PhBIAN)]­PF₆ (<b>1</b>), [Pt­(3Fppy)­(PhBIAN)]­PF₆ (<b>2</b>), [Pt­(3MeOppy)­(PhBIAN)]­PF₆ (<b>3</b>), [Pt­(3MeOppy)­(4-FPhBIAN)]­PF₆ (<b>4</b>), [Pt­(ppy)­(4-MeOPhBIAN)]­PF₆ (<b>5</b>). All complexes have been characterized by NMR spectroscopy and mass spectrometry. Complexes <b>2</b> and <b>3</b> have been characterized by X-ray crystallography. Structure–property relationships were established from UV–visible spectroscopy and cyclic voltammetry studies. Interestingly, we found that when both the C^∧N and the Aryl-BIAN ligands contained electron-donating MeO groups the absorption spectrum for the platinum complex extended out to 650 nm. The electrochemical studies of these complexes established that they are electronically compatible dye molecules for dye-sensitized solar cells

Cationic Platinum(II) Complexes Bearing Aryl-BIAN Ligands: Synthesis and Structural and Optoelectronic Characterization

Five cationic platinum­(II) complexes bearing a 2-(3′-substituted aryl)­pyridine cyclometalating ligand (C^∧N) and a neutral Ar-BIAN ligand have been synthesized: [Pt­(ppy)­(PhBIAN)]­PF₆ (<b>1</b>), [Pt­(3Fppy)­(PhBIAN)]­PF₆ (<b>2</b>), [Pt­(3MeOppy)­(PhBIAN)]­PF₆ (<b>3</b>), [Pt­(3MeOppy)­(4-FPhBIAN)]­PF₆ (<b>4</b>), [Pt­(ppy)­(4-MeOPhBIAN)]­PF₆ (<b>5</b>). All complexes have been characterized by NMR spectroscopy and mass spectrometry. Complexes <b>2</b> and <b>3</b> have been characterized by X-ray crystallography. Structure–property relationships were established from UV–visible spectroscopy and cyclic voltammetry studies. Interestingly, we found that when both the C^∧N and the Aryl-BIAN ligands contained electron-donating MeO groups the absorption spectrum for the platinum complex extended out to 650 nm. The electrochemical studies of these complexes established that they are electronically compatible dye molecules for dye-sensitized solar cells