Alkaloids ofArundo donax. IV. donaxanine — a new pyrrolidine alkaloid fromArundo donax

The new pyrrolidone alkaloid donaxanine, C₁₂H₁₄N₂O₂, has been isolated from Arundo donax. Its structure has been shown by chemical transformations and a study of its IR, mass, and PMR spectra as spiro[(N-methylpyrrolidin-2-one)-3,4-(3,1-benzoxazine).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 728–730, September–October, 1995. Original article submitted June 5, 1995.     

Ternatine, a new diterpene alkaloid fromDelphinium ternatum

A new alkaloid, ternatine (C₂₄H₃₃NO₅), was isolated from aerial parts of theDelphinium ternatum plant. According to the¹H,¹³C NMR, IR, and mass spectra of the base and its triacetate, ternative was assumed to have the structure of 4β-methyl-7α-isobutyryloxy-11α,15β,19β-trihydroxyhetisane. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 187–189, January, 1997.     

Alkaloids ofNitraria sibirica. Structure and absolute configuration of sibirinine

The chemical properties of sibirinine have been studied, its synthesis has been performed, and its¹H and¹³C NMR spectra have been analyzed. From the results obtained its structure and absolute configuration have been deduced.Institute of the Chemistry of Plant Substances of the Uzbek SSSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 685–689, September–October, 1987.     

Phytoecdysteroids of plants of the genusSilene XIV. Brahuisterone fromSilene brahuica

A new ecdysteroid with the composition C₂₇H₄₄O₆ which has been called brahuisterone has been isolated from the epigeal part of the plantSilene brahuica Boiss. Its chemical and complete spatial structures have been established by spectral studies and the x-ray structural method (diffractometer, Cu-K_α radiations, 996 reflections, direct method, R=0.119).     

Alkaloids of the Nitraria Genus. Komavine and Acetylkomavine

Two new alkaloids, komavine (1) and acetylkomavine (2) were isolated for the first time from the aerial part ofNitraria komarovii.Their ¹ H and ¹³ C NMR spectra were studied. Komavine was synthesized by condensation of tryptamine with cyclohexanone. These same alkaloids were also isolated fromNitraria schoberi     

Numerical solution of optimal control problems for loaded lumped parameter systems

An optimal control problem for the system of linear (with respect to phase variables) loaded ordinary differential equations with initial (local) and nonseparated multipoint (nonlocal) conditions is investigated. Necessary optimality conditions are obtained, numerical schemes of their solution are proposed, and results of numerical experiments are presented.     

Chemistry of Azobenzazole Systems. 3. Reactions of 2-Hydrazinobenzoxazole with Carbonyl Compounds

The reaction of 2-hydrazinobenzoxazole with various carbonyl compounds was studied. Only the corresponding azides were obtained with acylating agents such as acid anhydrides and acid chlorides and products with a fused triazole ring were not obtained. Only the corresponding hydrazones were obtained from furfural and 2-carboxy-3,4-dimethoxybenzaldehyde.     

Change of the magnetic-field topology by an ergodic divertor and the effect on the plasma structure and transport

The magnetic-field perturbation produced by the dynamic ergodic divertor in TEXTOR changes the topology of the magnetic field in the plasma edge, creating an open chaotic system. The perturbation spectrum contains only a few dominant harmonics and therefore it can be described by an analytical model. The modeling is performed in the vacuum approximation without assuming a backreaction of the plasma and does not rely on any experimentally obtained parameters. It is shown that this vacuum approximation predicts in many details the experimentally observed plasma structure. Several experiments have been performed to prove that the plasma edge behavior is defined mostly by the magnetic topology of the perturbed volume. The change in the transport can be explained with the knowledge of only the magnetic structures; i.e., the ergodic pattern dominates the plasma properties.