GC-ECD determination of traces of 3-phenyl-4-hydroxy-6-chloropyridazine after chemical derivatisation

Summary The development and application of a method for the determination of residue of 3-phenyl-4-hydroxy-6-chloropyridazine — the main metabolite of the new herbicide Pyridate — in matrices of cereals is described. The method involves after acetone extraction a three step clean-up process, derivatisation into 3-phenyl-4,6-dichloropyridazine and final measurement via Capillary-GC with EC-detection. The structure of the derivatisation product is confirmed by Capillary-GC/FTIR-spectroscopy combination.Detection and determination limits are estimated to be 5 ng/g and 20 ng/g respectively with recoveries between 90 and 96% in the 20 ng/g to 100 ng/g range. The part of the metabolite which is bound to the plant carbohydrates is released by acidic hydrolysis. The hydrolysation products are worked up and determined in the same way as the procedure for the free metabolite.

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GC-ECD-Bestimmung von Spuren von 3-Phenyl-4-hydroxy-6-chlorpyridazin nach Derivatisierung

Zusammenfassung Beschrieben wird die Entwicklung und Anwendung einer Methode zur Rückstandsbestimmung von 3-Phenyl-4-hydroxy-6-chlorpyridazin — dem ersten Metaboliten des neuentwickelten Herbizids Pyridate — in Getreide. Die Endbestimmung erfolgt mit Kapillar-GC mit EC-Detektion nach einer 3-stufigen Aufarbeitung und Derivatisierung zu 3-Phenyl-4,6-dichlorpyridazin. Die Struktur dieses Derivatisierungsprodukts ist mit Kapillar-GC/ FTIR-Spektroskopie bestätigt.Nachweis- und Bestimmungsgrenzen liegen bei 5 ng/g bzw. 20 ng/g, die Wiederfindung zwischen 90% und 96% im Konzentrationsbereich von 20 ng/g bis 100 ng/g.Der Anteil des Metabolits, der an die Kohlehydrate der Pflanze gebunden ist, wird durch saure Hydrolyse freigesetzt. Er wird nach derselben Aufarbeitungs- und Bestimmungsmethode, wie sie für den freien Metabolit Anwendung findet, erfaßt.

     

Determination of 3-phenyl-4-hydroxy-6-chloropyridazine in groundwater using enrichment on porous organic polymers

Summary A method is described for the determination of 3-phenyl-4-hydroxy-6-chloropyridazine in potable water. The method is based on isolation and enrichment by passing the water sample through a column of macroreticular polymeric adsorbent resin, concentration, derivatisation with pentafluorobenzoyl chloride and GC measurement with a N-specific detector. The individual experiments for establishing the working conditions, especially the adsorption characteristics of different types of resin, are described. The highest enrichment efficiency is obtained with the methacrylate-type resin XAD7. In field-sampling experiments a 10cm column yields 57% recovery at 100mLmin^–1 flow rate, 0.3 ppb concentration level and 1 L sample volume. The method is completely documented; performance data are a detection limit of 0.07 g L^–1 and a mean recovery of 75% at the 0.3 ppb level.     

Synthesis of 1,5-methano-2-benzazocines from 3-hydroxy-1,3-dimethyl-6-phenyl-4-piperidone

Reaction of 3e-hydroxy-1e,3a-dimethyl-6e-phenyl-4-piperidone with cyanoacetic ester affords 6e,8a-dimethyl-2-oxo-5e-phenyl-3-cyanofuro[2,3-c]piperidine, the epoxide of which undergoes intramolecular cyclization on treatment with 80% H₂SO₄, to give 1,2,5,6-tetrahydro-2-endo-4-dimethyl-1,5-methano-6-oxo-2-benzazocin-3-ene. It has been found that the latter is formed via the intermediate 3-hydroxy-6e,8a-dimethyl-2-oxo-5e-phenylfuro[2,3-c]piperidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1371–1374, October, 1986.     

Synthesis and biological evaluation of ethyl 6-alkoxy-7-phenyl-4-hydroxy-3-quinolinecarboxylates against Eimeria tenella

<正>A series of ethyl 6-alkoxy-7-phenyl-4-hydroxy-3-quinolinecarboxylates were designed and synthesized.Their structures were confirmed by ~1H NMR,~(13)C NMR,IR and HRMS.The biological activities were primarily evaluated against Eimeria tenella according to Anticoccidial Index(ACI) method in vivo.The results showed that compounds 5e,5f and 5i exhibited anticoccidial activities against E.tenella at 27 mg kg~(-1).     

Synthesis and Properties of 4,5-trans-2-Alkylthio-3-cyano-6-hydroxy-6-methyl-4-phenyl-5-pyridinio-1,4,5,6-tetrahydropyridine Iodides

Alkylation of 4,5-trans-4-aryl-3-cyano-6-hydroxy-6-methyl-5-pyridinio-1,4,5,6-tetrahydropyridine-2-thiolates 1, 2 was carried out. The presence of 5-pyridinio cation in thiolates 1, 2 as a strong electron-withdrawing group leads to a pronounced enhancement of their stability to dehydration but decreases their reactivity with electrophilic reagents. Steric structures of 2-alkylthio-6-hydroxytetrahydropyridines 3-5 are discussed in the light of ¹H NMR spectra and crystal X-ray diffraction data.     

A study of the acylation of 4-hydroxy-6-methyl-2-pyrone and 4 hy(lroxy-6-phenyl-2-pyrone

The acylation of 4-hydroxy-6-melhyl-2-pyrone (1) and 4-hydroxy-6-phenyl-2-pyrone (XXII) with aliphatic acid anhydrides, or with aliphatic acid chlorides in trifluoroacetic acid, has been found to product; first the corresponding ester, which then rearranges, partially or wholly, depending on the conditions and on the nature of the acyl moiety, to form the corresponding 3-acylpyrone. With aromatic acid chlorides in pyridine or in trichloroacetic acid only the corresponding ester was obtained. These esters, however, could be rearranged to the corresponding 3-acylpyrones with aluminum chloride. Acetoaeetylation of 1 and 4-hydroxycoumarin (XXIX) with diketene gave, in both cases, the C-acetoacetylated product.     

Spectrophotometric determination of selenium with 6-amino-1-naphthol-3-sulphonic acid (J-acid) and its application in trace analysis

A selective procedure for spectrophotometric determination of selenium with 6-amino-1-naphthol-3-sulphonic acid (J-acid) is described. In acidic conditions selenium forms a yellow complex with J-acid which has an absorption maximum at 392 nm. The molar absorptivity is 1.48 x 10(4) 1 mol(-1)cm(-1). Beer's law is obeyed for selenium in the range of 0.08-0.8 mg/1. The method has been applied to the determination of trace amounts of selenium in water, polluted water, plant material and steel plant dust. The proposed method is sensitive, rapid, simple and accurate.     

Spectrophotometric determination of titanium(IV) with 1-phenyl-2-methyl-3-hydroxy-4-pyridone

Analytical and Bioanalytical Chemistry -     

Synthesis and Properties of Ammonium 5-Benzoyl-4-(2-chlorophenyl)-3-cyano-6-hydroxy-6-phenyl-1,4,5,6-tetrahydropyridine-2-thiolates

The reaction of 2-chlorobenzaldehyde with cyanothioacetamide and dibenzoylmethane in the presence of piperidine or N-methylmorpholine gave the corresponding 5-benzoyl-4-(2-chlorophenyl)-3-cyano-6-hydroxy-6-phenyl-1,4,5,6-tetrahydropyridine-2-thiolates, used in the synthesis of 1-alkylthio-4-benzoyl-1-benzoylamino-3-(2-chlorophenyl)-2-cyanobut-1-enes.     

Structure of 4-amino-6-phenyl-5-cyano-2-cyclohexanespiro-1,3-dithia-4-cyclohexene and its recyclization to 5,6-tetramethylene-4-phenyl-3-cyano-2[1H]pyridinethione

Conclusions An intramolecular conformationally-rigid conjugation system was found in 4-amino-6-phenyl-5-cyano-2-cyclohexanespiro-1,3-dithia-4-cyclohexene. A probable mechanism for recyclization to the corresponding 2(1H)-pyridinethione was proposed on the basis of the geometrical parameters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1768–1774, August, 1985.     

Spectrophotometric determination of tungsten as a mixed thiocyanate-1-phenyl-2-methyl-3-hydroxy-4-pyridone complex

Spectrophotometric determination of tungsten with thiocyanate was described. Tungsten(VI) was reduced with tin(II) chloride in hydrochloric acid solution, complexed with thiocyanate ions, and the complex formed was extracted with 1-phenyl-2-methyl-3-hydroxy-4-pyridone (HX) in chloroform. The extracted complex had the ratio W:SCN:HX 1:3:2. The method described is sensitive, selective, and reproducible. The color of the tungsten-thiocyanate complex in the organic phase is stable. Few metals interfere; the separation of the interfering elements was discussed.