Acrylate-Assisted Arene–Chromium Bond Cleavage: Generation of a [Cr(CO)2] Fragment under Mild Conditions*

Displacement of the benzene ligand in 1 surprisingly occurs more readily than that of the methyl acrylate ligand. This paves the way for 1 to undergo arene exchange and arene substitution reactions, which may be triggered by a η²→η⁴ haptotropic rearrangement of the acrylate. Complex 1 is thus a mild precursor of the highly unsaturated fragments [Cr(CO)₂] (see scheme) and [Cr(CO)₂(η₂-acrylate)].     

New half life limits for theβ β 2v+0v decay of76Ge to the excited states of76Se from the Heidelberg-Moscow ββ experiment

Half life limits for theββ _2v+0v decay of⁷⁶Ge to excited states of⁷⁶Se are deduced from the background spectrum of a passive shielding of zone refined germanium (139.5 kg). A special low-activity HPGe-detector (102 ccm) was mounted inside this shielding to search for the transition photons emitted in the decay of the excited states. The resulting limits for the (0⁺→2 ₁ ⁺ and the (0⁺→0 ₁ ⁺ ) transition are 6.3·10²⁰ y (68%cl).     

Synthesis and high-resolution NMR spectra of A-nor-derivatives of 11-deoxyglycyrrhetic acid

Several skeletal and oxidative transformations of 11-deoxyglycyrrhetic acid were carried out to produce A-nor-derivatives. Signals for protons and C atoms in the PMR and ¹³C NMR spectra of the A-nor-derivatives were assigned using high-resolution ¹H (400 MHz) and ¹³C (125 MHz) NMR spectroscopy. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 445–448, September–October, 2006.     

Triterpene glycosides of plants of the family Caryophyllaceae

In this review, tables of 25 glycosides are given and the previously unknown structures of 11 of them are established. Characteristic features of the glycosides of the family Caryophyllaceae are considered. Methods are shown for isolating the glycosides and, using acanthophylloside B — a compound having carbohydrate chains of complex structure — as example, methods of determining their structures are demonstrated.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 417–433, July–August, 1981. Original article submitted May 6, 1981.     

Xanes for Pd and Pt in square and octahedral chloride complexes

Inorganic Chemistry Institute, Siberian Branch, Academy of Sciences of the USSR. Catalysis Institute, Siberian Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 29, No. 2, pp. 68–76, March–April, 1988     

The first optically active organometallic porphyrin:meso-tetrakis[(1S)-2-methylcymantrenyl] porphine

Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 959–961, May, 1994.The present work has been financially supported by the Russian Foundation for Basic Research (Project 93-03-5827) and the Russian State Scientific and Technical Program Ecologically Safe Processes in Chemistry and Chemical Technology.