O-methylcyclovirobuxine-D — A new alkaloid fromBuxus sempervirens

The amounts and compositions of the essential oils in the leaves and fruit of Meyer's lemon in the various vegetation periods have been studied. It has been established that as the fruit ripens the amount of essential oils and of monoterpene hydrocarbons in its peel and in the leaves increases.Institute of Plant Biochemistry, Academy of Sciences of the Georgian SSR. Sukhumi Zonal Experimental Station of Essential-Oil Crops. Sukhumi Experimental Station of Subtropical Crops, All-Union Institute of Plant Growing. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 784–787, November–December, 1985.     

Reaction of 3-Benzoyl-2,3-dibromopropionic Acid with Substituted ortho-Phenylenediamines

3-Benzoyl-2,3-dibromopropionic acid reacts with 4-substituted o-phenylenediamines to give 3-aryl-2-carboxymethylene-1,2-dihydroquinoxalines.     

Laboratory and Industrial Applications of Microwave Techniques

The use of microwave techniques in scientific research is reviewed. Also some semicommercial-scale microwave units are examined.     

Influence of the Structure of Cetyltrimethylammonium Bromide Based Microemulsions on Base Hydrolysis of Carboxylic Acid Esters

The structure of water/cetyltrimethylammonium bromide/n-butanol/hexane microemulsions was studied by conductometry, viscometry, and Fourier transform ¹H NMR spectroscopy with pulse magnetic field gradient. The regions of phase inversion from inverse micelles in hexane through a bicontinual structure to a dispersion of normal micelles in water were determined. The influence of the structure of the microemulsions on the rate of hydrolysis of carboxylic acid p-nitrophenyl esters was analyzed. The hydrolysis rate constants considerably increase in going from inverse to normal microemulsions.     

High-Sensitivity Determination of Hydrocarbon Impurities in Arsine by Reaction Gas Chromatography

It is shown that the results of determining methane in high-purity arsine by reaction gas chromatography can be overestimated by more than two orders of magnitude. This overestimation is caused by the formation of methane as a side product of the reaction. Cryogenic preconcentration at the injection stage is proposed to improve the accuracy of determination of methane, and the cryofocusing of impurity hydrocarbons is proposed to improve separation. Detection limits of (3–10) × 10^–6 vol % are achieved for C₁–C₅ hydrocarbons.