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The statements and discussions in this commentary are based on the disastrous situation near Baia Mare in Romania, where a dam of a cyanide basin burst on January 30, 2000, with serious consequences.

The phloroglucine derivatives (2 a–h) react with (+)-trans-p-menthadien-(2,8)-ol-(1) to give the oxygen analogous of (—)-Δ8-tetrahydrocannabinole such as 3 a–h. Some of these derivatives were converted by HCl-addition/elimination into the isomeric Δ9-compounds. The proposed structures of the derivatives are supported by spectroscopic data (1H NMR, IR and MS).

Using 14C-labelled dieldrin, the resorption, body distribution, and rate of excretion as well as the metabolism was investigated qualitatively and quantitatively. The experiments with mice, rats, rabbits, Rhesus monkeys, and chimpanzees were performed under identical conditions to obtain reliably comparable results.

The urea herbicide buturon (N-[p-chlorophenyl] -N' -methyl-N' -isobutinyl-urea), 14C-labeled, was sprayed on winter wheat as an aqueous formulation (2.98 kg/ha) under outdoor conditions. Upon harvest (three months after application), a total of 49. 2% of the applied radiocarbon was recovered: 2.0% in the plants, 46.9% in the soil, and 0.3% in the leaching water (depth > 50 cm); less than 0.1% was in the grains (0.464 ppm). Only about half of the radioactivity present in plants could be recovered under mild extraction conditions; about half of this was unchanged buturon. In straw and husk extracts, the following metabolites were identified by gaschromatography/mass spectrometry: N-(p-chlorophenyl)-N-methyl-O-methyl-carbamate (metabolite I), N-phenyl-N' -formyl-urea (metabolite II), two unstable metabolites giving (p-chlorophenyl)-isocyanate upon purification (metabolites III and IV), N-(p-chlorophenyl)-N' -methyl-N' -isobutenylol-urea (metabolite V), p-chloroformanilide (metabolite VI) and biologically bound p-chloroaniline (metabolite VII). In the root and basal stem extract, the following metabolites were identified by gas chromatography/mass spectrometry: N-(p-chlorophenyl)-O-methyl-carbamate (metabolite VIII) and N-(p-chlorophenyl)-N' -methyl-urea (metabolite IX).

In seven successive outdoor experiments, lindane-14C was applied to lettuce or endive leaves as an aqueous formulation (about 12 mg on 20 plants for each experiment). The growing periods varied between 21 and 37 days. After this time, between 4.5% and 13.9% of the applied radiocarbon was recovered from the plants. Conversion rates to soluble metabolites as well as to unextractable residues appeared to be dependent on weather conditions. During the summer months, the radiocarbon in plants consisted of 36% soluble metabolites and of 30% unextractable residues (average of 4 experiments); in autumn, the conversion rates were much lower. The following metabolites were identified in both plant species by gas chromatography/mass spectrometry: a polar group (a free trichlorophenol, 2,3,4,6-tetrachloropnenol, pentachlorophenol, conjugates of the latter two compounds, and unidentified water-soluble products) amounting to 35% of the radioactivity in plants cultivated in summer, and a nonpolar group (a dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3,5, and/or 1,2,4,5-tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, and γ-pentachlorocyclohexene amounting to 1% of the radioactivity in plants cultivated in summer.The 20 cm top-soil layer had about 14% of the total radioactivity applied to all plants. Six % of the radioactivity recovered from the soil was soluble metabolites and about 50% was not extractable. The soluble metabolites comprised a polar group (free and conjugated 2,3,4,6-tetrachlorophenol, pentachlorophenol, and unidentified water soluble products) amounting to 5% of the radioactivity in the soil as well as a nonpolar group (1,2,3-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,3,5 and/or 1,2,4,5-tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, and γ-pentachloro-cyclohexene) amounting to 1% of the radioactivity in the soil.

The biotransformation and disposition of 3-chloro-4-methyl-(4-14C)-7-hydroxycoumarin [(14C) chlorferron] were investigated in rats after single oral administration. Following administration of (14C) chlorferron at 0.5 and 20 mg/kg body weight to male rats, > 90% of the given dose was eliminated in the urine (77–84%) and faeces (7–15%) within 24 h. Low levels of (14C) chlorferron derived residues were detected in different organs of rats 7 days after dosing. Administration of (14C) chlorferron at 20 mg/kg allowed the isolation of three metabolites in the 24-h urine of male and female rats. Compounds tentatively identified were dechlorinated metabolites of chlorferron besides unchanged chlorferron. The majority of the metabolites were excreted in conjugated forms. The pattern of biotransformation of chlorferron was qualitatively similar in male and female rats. Comparative studies on the elimination and biodistribution of (14C) chlorferron and its parent compound (14C) coumaphos in male rats indicated rapid metabolism and faster elimination of chlorferron and its metabolites from the body than that of the parent compound.

Each of five male and five female rats was orally dosed with 49.2 μg 2,2'-dichlorobiphenyl- 14C daily for 42 days. After 36 days, the radioactivity in the body reached a plateau level, and male rats had excreted 84.5% of the applied radioactivity, females 87.9%; the residues in most organs were below 0.2 mg/kg. The daily excreted radioactivity after 50 days had decreased to 0.7% (males) and 0.5% (females) of the daily dose; the total excretion was then 86.2% (males) and 89.4% (females) of the total applied dose, and the organs contained <0.1 mg/kg. More than 90% of the radioactivity in the excreta was due to metabolites (one monomethoxy-, three monohydroxy-, three dihydroxy-, one trihydroxy-2,2'-dichlorobiphenyl, conjugates, and a dechlorinated derivative).

Controlled release formulations of the molluscicides niclosamide, Bayluscide, trifenmorph and mercaptodimethur have been prepared by incorporation into plates of ethylene-vinylacetate copolymer (EVA) in order to develop a more environmentally compatible method for controlling Schistosomiasis transmitting water snails. With the exception of mercaptodimethur, all substances were released into water at low rates from most formulations (<5% in 25 days). Attempts to influence release rates of niclosamide and Bayluscide by modifying the formulations have been successful in respect to increase as well as to decrease the substance release.

Die früher von uns als wachstumsfördernd für Strept. faecalis R erkannten Pteridine ließen sich in 2 Gruppen unterteilen, von denen die eine erst bei der Umsetzung mit Zuckern Aktivität erlangt. Die Umsetzung wird auf N-Glykosid-Bildung zurückgeführt. Zu dieser Gruppe gehört auch der 2-Amino-6.9-dioxy-pteridinaldehyd-(8), als dessen Vorstufe in Bakterien Iso-xanthop-terincarbonsäure wahrscheinlich gemacht wurde. Ihre Wirksamkeit wird durch die entsprechende 8-Essigsäure aufgehoben. Aminopterin vernichtet die Wachstumsaktivität aller als wirksam erkannten Pteridine.

Zur Klärung des biochemischen Syntheseweges der Pteroylglutaminsäure (Folsäure) wurden eine Reihe weiterer synthetischer Pteridine auf ihre Wuchs- bzw. Hemmstoffwirkung auf Streptococcus faecalis R untersucht. Es ließ sich zeigen, daß ihr Einfluß mit der früher geäußerten Vorstellung übereinstimmt, daß der 2-Amino-6.9-dioxy-pteridinaldehyd-(8) in glykosidierter Form eine Zwischenstufe darstellt, die über die 9-Oxy-pteroylglutaminsäure in Folsäure übergeht. Als eine Vorstufe des Pteridinsystems wurde das Pyrimidinderivat Vicin wahrscheinlich gemacht, während das Convicin keinen Einfluß auf das Wachstum ausübt. Es wird vermutet, daß die mangelhafte Fähigkeit dieses Bakteriums, Folsäure zu bilden, auf der Unfähigkeit beruht, Convicin in Vicin überzuführen.

Synthese und Eigenschaften von 3-Benzoyl-3.4-dihydro-1-thio-cumarin werden beschrieben. Durch Acyl-lacton-Umlagerung gelangt man zum 3-Äthoxycarbonyl-1-thioflaven (V). Abfangreaktionen mit Guanidin, Acetamidin und Phenylhydrazin führen zu den 4- bzw. 5-subst. Pyrazolonen-(5) (VIII) und 6-Hydroxypyrimidinen (VII a und VII b). Die NMR- und IR-Spektren der erhaltenen Verbindungen werden diskutiert.

In a-Stellung acylierte cyclische Carbonsäurederivate sind die Ausgangsverbindungen für zahlreiche O-S- und N-Heterocyclen nach dem Reaktionsschema der Acyl-lacton-Umlagerung.

In der Ordnung der Contortae lassen sich die einzelnen Familien, Unterfamilien usw. durch ihre chemische Synthesefähigkeit charakterisieren. Die Loganiaceae enthalten Alkaloide (Brucin, Strychnin) und leiten durch das Meliatin zu den Menyanthaceae über. Diese sind von den Gentianaceae getrennt durch deren Inhaltsstoff Gentiopikrin. Bei den formenreichen Apocynaceae bilden die Unterglieder getrennt voneinander Alkaloide, Steroidalkaloide und Cardenolidglykoside. Die Asclepiadaceae enthalten ihren Unterfamilien folgend Cardenolidglykoside und Bitterstoffe (Vincetoxintyp).