Pulchellin C and inuchinenolide C from Inula caspica

The pseudoguaianolide inuchinenolide C and the eudesmanolide pulchellin C have been isolated for the first time from the flower heads and leaves ofInula caspica Blume, and their spatial structures have been established by an x-ray structural experiment as 2,6-diacetoxy-6-hydroxy-1,7(H),8,10(H)-pseudoguai-11(13)-en-8,12-olide and 2,3-dihydroxy-5,7,8(H)-eudesma-4(15),11(13)-dien-8,12-olide, respectively.Institute of Organic Synthesis and Coal Chemistry, Academy of Sciences of the Kazakh SSR, Karaganda. A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 748–757, November–December, 1990.     

Thermochemistry of Sesquiterpene Lactone 3,4β-Epoxyarglabin

The enthalpies of dissolution of 3,4β-epoxyarglabin C₁₅H₁₈O₄ are measured via isothermal calorimetry at lactone: 96% ethanol molar ratios of 1: 6000, 1: 12000, 1: 24000 at 298.15 K. The standard enthalpy of dissolution of C₁₅H₁₈O₄ in 96% ethanol is calculated from the obtained data; the value is 40.1 ± 0.4 kJ/mol. The enthalpies of combustion, melting, and formation of 3,4β-epoxyarglabin C₁₅H₁₈O₄ are estimated by approximate means.     

Preparation and structure elucidation of two minor products from reaction of arglabin with chloroform in the presence of a crown ether

A pentachloro derivative, the structure of which was proved by x-ray structure analysis, in addition to a new dichlorocarbene derivative were obtained for the first time by dichlorocyclopropanation of arglabin guaianolide. The stereochemistry of the principal reaction product was established. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 450–452, September–October, 2007.     

Rhaposerine and rhaserolide, new sesquiterpene lactones fromRhaponticum serratuloides

Two new crystalline guaianolides,viz., rhaposerine and rhaserolide, were isolated from an ethanolic extract of the above-ground part of the plantRhaponticum serratuloides by column chromatography along with sesquiterpene lactones,viz., centaurepensin and acroptilin, which have been found in other plants. The chemical structures of the title lactones were established by¹H and¹³C NMR spectroscopy and 2D¹H−¹H (COSY) and¹³C−¹H (COSY and COLOC) NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2010–2014, October, 1999.     

Chemical modification of argolide

Chemical transformations have been made of argolide, a sesquiterpene lactone of the germacrane type, as a result of which new epoxy, amino, and hydroxy derivatives of it have been obtained.Institute of Phytochemistry, Academy of Sciences of the Republic of Kazakhstan, Karaganda, fax (3212) 433144, e-mail: arglabin@phyto, karaganda, su. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 188–192, March–April, 1999.