Crystal structure of a tetrabromo derivative of cyclopropyldihydroarglabin and its antifungal activity

A tetrabromo derivative of arglabin was synthesized stereoselectively. The molecular structure of the new compound was established using PMR and 13C NMR spectra and an x-ray structure analysis. Its antifungal activity was demonstrated. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 253–254, May–June, 2006.     

Epoxidation of sesquiterpene lactones tourneforin and ludartin

Epoxy derivatives of the sesquiterpene lactones ludartin and tourneforin were synthesized. Their structures were elucidated using spectral data and x-ray structure analysis.     

Structure of the Intermediate in the Addition Reaction of Dialkylphosphorous Acids to Grosshemin

The intermediate in the reaction of grosshemin and dialkylphorphorous acids was isolated and characterized structurally. It has been found that addition of a dialkylphosphite anion occurs under these reaction conditions first at an exomethylene and then at the ketone of grosshemin.     

Synthesis of Dihalocarbene Derivatives of Arglabin

Dibromocarbene and bisdichlorocarbene derivatives of the available sesquiterpene lactone arglabin were synthesized for the first time. The structures of the molecules were established by spectra methods and XSA. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 451–453, September–October, 2005.     

Phosphorus Derivatives of Natural Lactones. Synthesis of New Grosshemin Dialkylphosphonates

New phosphorus-containing derivatives of grosshemin were synthesized in 68-70% yield by reacting this guaianolide with dialkylphosphites. Their structures were established by IR, PMR, ¹³C NMR, and ³¹P NMR spectroscopies and two-dimensional ¹H-¹H NMR spectroscopy (COSY). The reaction of grosshemin with dialkylphosphites was found to be highly stereoselective.     

Thermodynamic Properties of Dimethylaminoarglabin Methyl Iodide C1 8H2 8O3NI and Its Analogs

The heat of solution of dimethylaminoarglabin methyl iodide C_{1 8}H_{2 8}O₃NI at dilutions (mole of salt/mole of water) of 1 : 75000, 1 : 100000, and 1 : 150000 was determined by isothermal calorimetry. The data obtained were used to calculate the standard heat of solution of the compound in an infinitely dilute (standard) aqueous solution. The heats of combustion, melting, and formation of C_{1 8}H_{2 8}O₃NI and 33 its analogs were estimated by approximate methods of chemical thermodynamics.     

Phosphate Derivatives of Natural Lactones. I. Synthesis of Novel Isoalantolactone Dialkylphosphonates

Novel isoalantolactone dialkylphosphonates were synthesized in 70-87% yields by reacting this eudesmanolide with dialkylphosphites. Their structures were proved by spectral analysis using IR, PMR, ¹³C and ³¹P NMR, and two-dimensional ¹H-¹H (COSY) spectroscopy. The reaction of isoalantolactone with dialkylphosphites is highly stereoselective.