Synthesis of nitrocyclopropanedicarboxylic acid derivatives by addition of ��-bromonitroalkanes to methylidene malonic, methylidene cyanoacetic or maleic acid derivatives

A potassium carbonate promoted addition of 2-bromonitroalkanes to methylidenemalonic and methylidenecyanoacetic acid derivatives and N-benzylmaleimide leads to the functionalized nitrocyclopropanes. In the case of less active olefins, it is reasonable to use the phase-transfer catalyst Bu₄NPF₆ (10 mol.%), whereas in the case of N-benzylmaleimide, to carry out the process in the ionic liquid [bmim]BF₄.     

Triterpene Glycosides of Scheffleropsis angkae. IV. Structure of Glycosides L-C2 and L-I2

Two new triterpene glycosides of the -amyrin series, L-C ₂ and L-I ₂ , 27-hydroxyursolic acid 3-O--L-arabinopyranoside and its 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl ester, are isolated from leaves ofScheffleropsis angkae(Araliaceae). The structures of the glycosides are established using chemical methods and NMR techniques ( ¹ H, ¹³ C, ¹³ C-APT, COSY, TOCSY, HSQC, HMBC, and ROESY).     

Diastereoselective synthesis of polyfunctional compounds based on the tandem sequence of threeAd E reactions using cyclic vinyl ethers as first alkene components

The reaction of the bicyclic thiophanium ions salts, generated by the sequential interaction ofp-TolSCI with dihydropyran or 1-methoxycycloalkene and then with an acyclic alkyl vinyl ether in the presence of a Lewis acid and with silicon- or tin-capped π-donors, proceeds with high diastereoselectivity at all newly created chiral centers. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 82–94, January, 2000.     

Laser Effect in the Explosion of Porous Silicon

JETP Letters - In the explosive reaction of composites based on porous silicon with perchlorate oxidizers, a new effect has been discovered: the intensity accompanying the explosive reaction...     

Calculation of the Efficiency of the Higher Order Mode Damping in a 350 MHz Accelerating Cavity Using Waveguide Power Output Devices

Physics of Atomic Nuclei - In this paper, two options for damping higher order modes (HOMs) using rectangular waveguides and corrugated cylindrical waveguides are considered. The tuning of the two...     

Reactions of aminoguanidine and guanidine with 3- and 5-formyl-4-arylaminopyridones

Amidinohydrazones were prepared by the condensation of 4-arylamino-2-oxo-5-formyl-1,2-dihydropyridine-3-carbonitriles and 4-arylamino-2-oxo-1,2-dihydropyridine-3-carbaldehydes with aminoguanidinium carbonate with the purpose to investigate their biological activity as putative NO donors. The reaction of 5- и 3-formylpyridones with diguanidinium carbonate was studied. The formation of stable complexes of 4-arylamino-5-formyl-2-oxo-1,2-dihydropyridine-3-carbonitriles with aminoguanidine and guanidine was discovered. Amidinohydrazones obtained possess antiinflammatory, antidiabetic, and antihypertensive activities.     

Structure of 2(5)-alkyl-4-hydroxy-3,4-diphenylcyclopent-2-en-1-ones,cyclocondensation products of benzil with aliphatic ketones

The reaction of benzil with methyl alkyl ketones gave three isomeric cyclopentenone derivatives, 2-substituted and cis- and trans-5-substituted 4-hydroxy-3,4-diphenylcyclopent-2-en-1-ones. cis- and trans-2,5-Disubstituted 4-hydroxy-3,4-diphenylcyclopent-2-en-1-ones were formed in analogous reaction of benzil with dialkyl ketones. The structure of the products was confirmed by ¹H NMR spectroscopy and molecularmechanics calculations.