Sulfur ylides. 3. Synthesis of keto-group stabilized amino-containing sulfur ylides from amino acids

An effective path of synthesis was developed of new synthetic intermediates, the optically active, keto-group stabilized amino-substituted sulfur ylides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 612–620, March, 1990.     

On the dynamics of a two-mode laser with periodically modulated parameter

The results for a numerical simulation of a two-mode homogeneously-broadened laser due to a periodic pump modulation are presented. The region with the parameters for the complicated periodic and chaotic laser-intensities pulsation to be observed has also been defined. Complex bifurcation diagram versus modulation frequency with the periodic and chaotic regimes alternation is presented.     

13C NMR spectra of biologically active compounds.

The¹³C spectra of 25 new substituted cyclopropanes of the pyrethoid series have been investigated and a stereochemical assignment has been made of the stereoisomers formed. As the criterion for stereochemical assignment it is proposed to use the values of the chemical shifts for the -carbon atoms of the substituents in the cyclopropane ring.Institute of Chemistry, Bashkir Branch, USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 266–272, March–April, 1989.     

Synthesis of β-D-xylofuranosyl- and 2,2′-anhydro-1-β-D-lyxofuranosylpyrimidine nucleosides

-D-Xylofuranosylpyrimidines were obtained by condensation of silyl derivatives of pyrimidines with 1,2-di-O-acetyl-3,5-di-O-benzoyl-D-xylofuranose with subsequent deprotection of the sugar fragment. Refluxing 2-O-tosyl derivatives of nucleosides with NaI results in the formation of 2,2-anhydro-compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1137–1141, June, 1993.     

Triterpenoids from the Aerial Parts of Kalidium foliatum

Studies on the chemical constituents of the aerial parts of Kalidium foliatum led to the isolation of three new olean‐12‐ene‐23,28‐dioic acids in their either partly or fully esterified forms (Me or glucosyl (Glc) esters), which were named kalidiumoside A ( 1 ), kalidiumin ( 2 ), and kalidiumoside B ( 3 ). Their structures were elucidated through spectral studies including 2D‐NMR experiments (HMQC, HMBC, COSY, NOESY) and J‐resolved spectra. Also isolated were the two known compounds dianic acid and dianoside F, which were identified through comparison of their spectroscopic data with those reported in the literature.     

Reactions of diazoalkanes with unsaturated compounds 16. Catalytic reactions of diazomethane with 2-alkenyl-1,3-oxazolidines and 2-alkenyl-1,3-oxathiolanes

The influence of 1,3-oxazolidine and 1,3-oxathiolane fragments in substituted alkenes on the direction of their catalytic reaction with diazomethane has been investigated. The olefins bearing an oxazolidine substituent in the α- or γ-position and an oxathiolane substituent in the γ-position relative to the C=C bond react with diazomethane in the presence of Pd(acac)₂ selectively resulting in cyclopropanation products. The use of Cu(OTf)₂ does not result in cyclopropanation; however Cu(OTf)₂ catalyzes the reaction of diazomethane with 2-(alk-1-enyl)-1,3-oxathiolanes yielding 2,3,5,6-tetrahydro-1,4-oxathiocines formed through the [2,3]-sigmatropic rearrangement of the intermediate sulfonium ylides. For Part 15 see Ref. 1. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 604–608, March, 2008.     

Cu(OAc)2-2,4-lutidine-ZnCl2 as an effective catalyst of functionalization of isobutylene oligomers and 1,2-polybutadiene with methyl diazoacetate

The possibility of [1+2]-cycloaddition of methoxycarbonylcarbene generated by catalytic decomposition of methyl diazoacetate in the presence of the Cu(OAc)₂-2,4-lutidine-ZnCl₂ system to the carbon-carbon double bound in isobutylene oligomers and syndiotactic 1,2-polybutadiene was examined. A comparative analysis of physicochemical properties of the starting compounds and their functionalized products was performed.     

Cationic peptides and proteins from seeds of plants of the family Malvaceae

Total cationic peptides from seeds of plants of the family Malvaceae were separated by chromatography. The molecular weights of the isolated peptides were determined by MALDI-TOF mass spectroscopy. The antifungal activity of total cationic peptides from seeds of plants of this family against Phytophtora infestans was demonstrated on potato disks.     

Numerical modelling of unsteady heating and melting of the anode by electric arc. Part 2. Numerical characteristics of the anode weldpool

Numerical computations of the electric-arc heating and anode melting were carried out within the framework of the two-dimensional unsteady mathematical model. The influence of the viscous interaction ??plasma-melt??, surface tension forces, electromagnetic forces, and gravitational convection on the formation of the hydrodynamics of the anode melt was considered.     

Phosphazenes: I. Reactions with electron-deficient alkenes

Triphenylphosphazenes reacted with methyl vinyl ketone, methyl acrylate, methyl methacrylate, and dimethyl maleate to give the corresponding substituted dihydropyrazoles.