Coumarins of Ferula kopetdaghensis and the structure of kopeolin and kopeoside
SummaryThe roots ofFerula kopetdaghensis Eug. Kor. have yielded five coumarins — umbelliferone and four new compounds (kopetin, kopeodin, kopeolin, and kopeoside).On the basis of NMR, mass, and IR spectroscopy, derivatives, and transformation products, the structures of two of the new coumarins kopeolin and kopeoside have been established. It has been shown that kopeolin is a derivative of farnesiferol C and kopeoside is kopeolin 3-O-β-D-glucoside.
Zur Kenntnis der Sesquiterpene und Azulene. 127. Mitteilung. Über die Inhaltsstoffe der Asa foetida II. Farnesiferol B und C
Structures III and XXV have been derived on the basis of degradative work and physical evidence for Farnesiferol B and C, two isomeric C24H30O4 compounds previously isolated from Asa foetida (Umbelliferae).
Comparison of different antenna configurations for probing of layered media
The paper presents the results of a comparative analysis of the different configurations of antenna systems (bistatic, monostatic, differential) in terms of the simplicity and accuracy of determining the thickness of the subsurface layers of stratified environment. To this end, corresponding diffraction problems are solved by the finite-difference time-domain forward solver for each measurement setup. The analysis has shown the advantages and prospects of using differential system with vertically spaced antennas in solving of practical problems of the layered medium GPR probing.