Band-Gap Determination from Photoconductivity Excitation Spectra

Journal of Applied Spectroscopy - The possibility to determine the direct and indirect band gap from the photoconductivity spectrum is shown. The band gap determined from the photoconductivity...     

Electron-impact mass spectra of natural phenylethanoids

The electron-impact mass spectra of a number of phenylpropanoids and iridoid glycosides containing a phenylethanoid fragment in their structure have been studied. This has revealed features of the formation of fragments of 4-hydroxyphenylethyl and 3,4-dihydroxyphenylethyl alcohols and also of fragments of phenylethylamine and indolylethylamine derivatives present in the structures of the compounds investigated.     

Automatic activation analysis of fertilizers and plant samples by fast neutrons

Instrumental neutron activation methods are suggested in order to carry out automatic analysis of fertilizers and plant samples for N, P, K and Si allowing for the investigation of more than 40 samples per 8 hours. The experimental errors do not exceed ±3% for N, ±6% for P, ±5% for K and ±15% for Si.     

Investigations in the fie ld of substituted furanurona ldehydes steric directivity of the nitromethane condensation

Summary 1. The condensation of the anomeric methyl 2,3-di-O-benzyl-D-xylofuranosiduronaldehydes with nitromethane has been studied.2. It has been shown that the position of the substituent at the glycosidic center has an influence on the steric directivity of this reaction.3. The structure of the 6-nitro-6-deoxyhexofuranosides synthesized has been confirmed by their conversion into known derivatives of methyl D-glucofuranosides.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 8–12, January–February, 1972.     

Effect of matrix annealing on ethyl radical oxidation in methanol-d4 glass at 87 K

The effect of matrix annealing on ethyl radical oxidation in excess oxygen has been studied by an ESR method. The annealing decelerates the nonstationary kinetics making it close to the exponential one. It has been shown that the nonstationarity cannot be attributed only to annealing.

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Alkaloids of a new type fromSophora alopecuroides L.

Summary The structures of aloperine and allylaloperine (fromSophora alopecuroides L.) — alkaloids of a new structural type for the genusSophora — have been established by chemical and spectral methods. A number of parameters, NMR spectra, and mass spectra characterizing this class of compounds has been obtained. The partial synthesis of allylaloperine has been performed.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–37, January–February, 1975.     

Benzyl cleavage in the oxidation of cycleanine by mercuric acetate

The dehydrogenation of cycleanine with mercuric acetate in 10% AcOH (at the boil) has been studied. It has been shown that it is accompanied by oxidative cleavage similar to benzyl cleavage under the action of electron impact. The main reaction product (without complexone) is the 8-(4-hydroxymethylphenoxy)-6,7-dimethoxy-2-methylisoquinolinium salt C₁₉H₂₀NO₄Cl·1.5H₂O, mp 196°C. The oxidation of cycleanine in the presence of ethylenediaminetetraacetic acid gave the mercuride C₁₉H₁₉NO₃I₂Hg·2H₂O, mp 240°C (water).All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 676–680, September–October, 1979.