The percutaneous absorption of the xenoestrogen 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A) 1 has been studied and compared with results on dibenzoyl peroxide 2, a component of drug formulations for topical application. Isolated perfused bovine udders from slaughtered cows were employed as models for human skin. The deuterium labelled compounds 1-d14 and 2-d10 were applied to enhance the reliability of GC-MS trace determinations by use of reverse isotope dilution analysis. 1-d14 was found in perfusate and milk equivalent samples obtained between 60 and 300 min after topical application with maximum concentrations between 120 and 180 min. 1-d14 was enriched in the milk samples by a factor of about 300 compared with the perfusate. The results confirm a possible penetration of 1 from the environment through the skin into the capillary system. 2 studied on the same model system penetrated faster than 1 by a factor of about three.

mer‐Trichloro(2,2′‐bipyridin)nitridotechnetium(VI), [TcNCl3(bipy)], entsteht bei der Reaktion von (NBu4)[TcNCl4] mit 2,2′‐Bipyridin in Acetonitril, während die gleiche Umsetzung in Methanol das Technetium(V)‐Kation [TcN(Cl)(bipy)2]+ liefert. Die EPR‐Spektren von [TcNCl3(bipy)] weisen auf eine meridionale Koordination der Chloro‐Liganden hin. [TcNCl3(bipy)] kristallisiert monoklin in der Raumgruppe P21/n; a = 8,572(1); b = 15,462(1); c = 10,110(1) Å; β = 104,21(1)° mit Z = 4. Auf der Grundlage von 3 040 gemessenen Reflexen wurde ein R‐Wert von 0,034 erreicht. Das Technetiumatom befindet sicht in einer verzerrt oktaedrischen Umgebung. Die drei Chloroliganden sind meridional‐cis zum Nitridostickstoff angeordnet. Der Bindungsabstand TcN(1) beträgt 1,669(4) Å. Durch den starken trans‐Effekt des „N3−”︁‐Liganden ist die TcN(3)‐Bindung stark aufgeweitet (2,371(4) Å).

A technical mixture of isomeric nonylphenols NP is formed as rather persistent degradation product of nonionic surfactants and has become widespread in the environment, e.g., in surface waters. Information about possible pathways for incorporation is needed for risk assessments, as NP has estrogenic properties. NP uptake after skin contact was determined using isolated and perfused bovine udders as models for human skin. NP-d2 labelled in the positions ortho to the OH-group was prepared by an exchange procedure which did not measurably change the relative amount of isomers. Samples of udder perfusate, milk equivalent produced during the experiments and skin tissue were taken immediately before administration of 500 mg or 50 mg NP-d2 on an udder skin area of 200 cm2 and then for 5 h. They were analyzed by GC-MS for NP and NP-d2 after cleanup by steam distillation and final extraction with SPME fibres. The results are an unambiguous proof of the penetration of NP into the capillary system of living mammals after skin contact.

The cathodic reduction of dibenzofuran (2), 2‐chlorodibenzofuran (4), and 3‐chlorodibenzofuran (1) in deuterated methanol is investigated. The Birch‐type reduction product 1,4‐dibenzofuran (3) is formed from 1 via 2, whereas 2‐chloro‐1,4‐dihydrodibenzofuran (5) is obtained as by‐product besides 3 from 4 as starting compound. Deuterium is only incorporated into the reduction products if CH3OD or CD3OD but not if CD3OH are used. This observation is strongly indicative of a polar mechanism involving protonation rather than a radical mechanism with hydrogen atom abstraction to be operative.

The kinetic hydrogen isotope effects in electrochemical reductions of CCl,COOD, CDClzCOOD, CCb, CDCl2, benzyl chloride, lchloronaphthalene and Cchlorobenzonitrile in deuterated reaction media were determined. The aliphatic chloro compounds are reduced with rather small isotope effects kH/kD = 1.2.. . 1.7, as expected if anionic intermediates are formed and protonated. Benzyl chloride is reduced with an apparent kH/kD = 2.1, which is probably too high due to radical reactions. Aromatic chloro compounds are reduced with significant participation of a second mechanism via radical intermediates which abstract carbon-bound hydrogen atoms from the components of the reaction system. The resulting isotope effects are kH/kD = 1.2 for the part of the reduction which proceeds via anions and kH/kD -2.5 for the competing radical reaction.