Investigations on carotenoids in lichens. XXXII. Carotenoids occurring in the thalli of lichens from Kenya (Equatorial Africa)

The presence of cartenoids in nineteen species of lichens from Kenya (Equatorial Africa) was studied by column and thinlayer chromatography. This investigations revealed the presence of the following carotenoids: neurosporene, α-carotene, β-carotene, rubixanthin, α-cryptoxanthin, β-cryptoxanthin, zeaxanthin, lutein, 3'-epilutein, torularhodin, diatoxanthin, neoxanthin, echinenone, 3'-hydroxyechinenone, canthaxanthin, α-doradexanthin, astaxanthin, β-carotene epoxide, antheraxanthin, lutein epoxide, violaxanthin, mutatoxanthin, flavoxanthin, capsochrome, β-apo-8'-carotenal, β-apo-10'-carotenal and apo-12'-violaxanthal. Five of these, torularhodin, 3'-hydroxyechinenone, capsochrome, β-apo-8'-carotenal and β-apo-10'-carotenal, are reported for the first time from lichens. The total carotenoid content of the material ranged from 15.88 (Pyxine cocoes) to 135.44 µg g-1 dry weight (Telaschistes chrysophthalmus).

Synthesis of new compounds of the aryloxyaminopropanol type and their HPLC enantioseparation

This article describes a preparation of some new compounds of the aryloxyaminopropanol type derived from 4-hydroxyphenylpropan- 1-one with phenylamino, cyclohexylamino and isobutylamino group in the hydrophilic part and methoxymethyl or ethoxymethyl substituent in the lipophilic part of the molecule. The purity of the prepared compounds was checked by thinlayer chromatography and the structure was confirmed on the basis of interpretation of the IR, UV, 1H NMR and 13C NMR spectra. An enantioseparation of the prepared compounds was performed by using high-performance liquid chromatography on an amylase tris(3,5-dimethylphenylcarbamate) (Chiralpak AD) and native teicoplanin (Chirobiotic T). The chromatographic results such as retention, separation and resolution factors have shown that Chiralpak AD is more suitable for enantioseparation of some of the prepared compounds.

Hydroxylamin-Funktion als Nachbargruppe bei Dehydrierungen / Hydroxylamine Function as Neighboring Group with Dehydrogenations

The β -amino-hydroxylamines 5a - d are prepared of the α-amino-oximes 1a - d with boranedimethylsulfide. With mercury-EDTA, 5a - d react to (E/Z)-oxime-lactams 3a - d and benzaldoxime 7. Additionally 5b,c give the bicyclic amidine-N-oxides 8b,c, which slowly hydrolyze to the hydroxylamine-lactams 9b,c. These are easily oxidized to (E/Z)-3b,c. Postulated as intermediates in the mercury-assisted reduction of 5, the cyclic hydroxylamines 10a - d are available from the nitrones 4a - d with LiAlH4. From 10a - d with mercury-EDTA the same products are obtained as from 5a - d but without 7. Only the pyrrolidine 10a forms besides (E/Z)-3a the nitrone 4a. Thinlayer chromatography shows that the pure isomers of 3a - d in solution isomerize, contrary to the amine-oximes 1a - d. The configuration of the oxime-lactams depends on the manner of preparation. With mercury-EDTA, 1b,c yield 3b,c with retention of the configuration, while the oximation of phenacyl-lactams 13b,c give rise to (E/Z)-mixtures of 3b,c. The condensed imidazoles 12 result from the nitrones 4a - d and the dihydrooxadiazines 2a,d on treatment with hydrogen chloride.

Detection and Separation of Fenpropathrin, Flucythrinate, Fluvalinate, and PP 321 by Thin-Layer Chromatography

Four synthetic pyrethroids having α-cyano ester groups, i.e., fenpropathrin, flueythrinate, fluvalinate, and PP 321, are separated by thinlayer chromatography and detected by a new set of chromogenic reagents. Synthetic pyrethroids containing the α-cyano group react with sodium hydroxide to liberate cyanide which forms pink spots with o-dinitrobenzene and p-nitrobenzaldehyde. The detection limit is 0.1 μg and the method can be applied for identification and confirmation of these synthetic pyrethroids in vegetables.

Analysis of Natural Coloring Matters in Food. III. Applications of Methylation with Diazomethane for the Detection of Lac Color

A new method has been proposed for detection of lac color in food. Lac color is a natural color additive derived from a secretion of the insect Coccus Laccae (Laccifer lacca Kerr). It is extracted from food with methanolic oxalic acid and eluted from a column of Amberlite XAD-2 with the same solvent. The fraction containing the lac color is treated with diazomethane to produce 2 reddish-orange markers. The marker species in the reaction mixture are detected by both thinlayer chromatography and reverse-phase liquid chromatography.

Thin-Layer Chromatographic Determination of Sterigmatocystin in Cheese: Interlaboratory Study

A collaborative study of a method for the determination of sterigmatocystin in cheese was conducted by 10 laboratories. The study included control samples and samples spiked at levels of 5, 10, and 25 ppb, in coded blind pairs. Recoveries were 60.0, 90.7, and 59.3%, outliers excluded, for the respective levels. The mean reproducibilities, outliers excluded, were 81.97, 17.13, and 52.77%, respectively. Mean repeatabilities, outliers excluded, were 77.66,17.13, and 46.40%, respectively. Results of this collaborative study indicate that the method, modified as described in this report, is applicable to the determination of sterigmatocystin in cheese at low levels (5-50 ppb) for the purpose of surveys. With regard to the difficulty with thinlayer chromatography in this study, it is recommended that a more satisfactory determinative step be developed. Recommendation for official first action status is deferred

Absorption, Translocation, and Metabolism of Bentazon in Sunflower (Helianthus annum)

Addition of a surfactant (alkylaryl polyglycol ether) increased the rate and quantity of14C-bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] absorbed by leaves of 3-week-old hydroponically grown sunflower (Helianthus annuusL.). Autoradiographs and radioassays of plant parts indicated that the surfactant enhanced acropetal movement of bentazon in sunflower, whereas bentazon applied alone remained in the treated leaves. Basipetal movement of14C-bentazon was insignificant in sunflower. High-pressure liquid chromatography showed that 3 days after treatment 40% of the absorbed14C-bentazon was metabolized to a methanol-soluble metabolite. Thinlayer chromatography substantiated the occurrence of a14C-bentazon metabolite 3 days after treatment.