Reactions of stereoisomeric 3,4-epoxycaranes with alcohols in acidic media

Conclusions In the reaction of the cis-isomer of 3,4-epoxycarane with alcohols in acidic media, opening of the oxide ring was less regioselective than in the case of the -isomer. Rearrangement of the trans-isomer of 3,4-epoxycarane with transannual cyclopropyl participation occurs only in reactions with a secondary alcohol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 648–653, March, 1985.     

Conformational analysis of substituted 1-cycloheptene-5,6- and 1-cycloheptene-6,7-diols from ir,raman, and pmr spectra

Conclusions For a number of substituted vic-cycloheptenediols the chair conformation with a transdiequatorial orientation of hydroxyl groups is suggested by the data of PMR in CDCl₃. The data of IR and Raman spectra of dilute solutions of these compounds in CCl₄, indicate the possibility of multiple conformations due to the different orientation of OH groups forming intramolecular hydrogen bonds or, depending on the nature of substitution, in twist boat forms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1980–1984, September, 1987.The authors wish to thank A. V, Il'yasov for discussing the work.     

Methanolysis of stereoisomeric 4β-chloro-3,10-epoxycaranes

Conclusions Under conditions of acid methanolysis, the stereoisomeric 4-chloro-3,10- and 3,10-epoxycaranes form addition products with predominant cleavage of the oxide ring at the C₁₀-0 bond, while on alkaline catalysis they form products with cleavage of the C₃-0 bond.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2809–2812, December, 1987.     

Synthesis of Schiff bases on the basis of the isosteviol terpenoid

The transformation of the carboxy and keto groups of the isosteviol (ent-16-ketobeyeran-19-oic acid) diterpenoid was used to synthesize its new nitrogen-containing derivatives, including Schiff bases by the C⁴ and C¹⁶ atoms of the isosteviol frame. The structure of the resulting compounds was established by X-ray diffraction.     

Glycosides from <Emphasis Type="Italic">Stevia rebaudiana</Emphasis>

A new laboratory method for isolating the glycosides stevioside and rebaudiosides A and C from leaves of Stevia rebaudiana was proposed. According to HPLC, the glycoside contents in plants grown in Russia (Voronezh Oblast’) and Ukraine (Crimea) were 5–6% (stevioside) and 0.3–1.3% (rebaudiosides A and C). __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 68–71, January–February, 2007     

Alkylation of the isosteviol terpenoid and its oxime with dibromoalkanes in the KOH-DMSO system

The reaction of 16-hydroximinoisosteviol with dihaloalkanes in the KOH-DMSO results in coupling of two isosteviol carcasses by the carboxy groups. The same products were previously synthesized by hydroximination of isosteviol diesters.