Mechanism of tee cyclooligomerization of butadiene in the presence of low-valence nickel complexes

Conclusions The kinetic behavior of the cyclooligomerization of butadiene on the Ni(acac)_a-(C₂H₅O)Al(C₂H₅)₂ catalytic system was studied and the most likely kinetic model for this process was proposed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1509–1515, July, 1980.     

Claisen rearrangement taking place in the mass spectrometer

Conclusions The Claisen rearrangement of bucharaine and of the aldehyde bucharainal takes place under the conditions of mass spectrometry. At low temperatures inversion predominates and at high temperatures the anomalous rearrangement.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 577–583, September–October, 1970.     

Studies on pyran,its analogs,and related compounds

The action of guanidine on esters of chromone-2-carboxylic acids leads to the opening of the pyrone ring and to the formation of hydantoin derivatives — 2-imino-5-(2-hydroxybenzoylmethylene)tetrahydroimidazol-4-ones — in addition to other reaction products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 874–875, July, 1970.     

Conformation of hedycaryol isomers

Ground state conformation for all possible geometrical isomers of hedycaryol was estimated by the molecular mechanics calculations. All isomers are indicated to exist in more than two conformations and the parallel conformation (TC or TT) is most stable for all isomers.     

Triterpene glycosides ofScabiosa soongorica

Partial syntheses of glycosides of oleanolic acid — the 3-0-β-D-xylopyranoside (songoroside A), the 3,28-bis-0-β-D-xylopyranoside, and the 28-0-β-gentiobioside-3-0-β-D-xylopyranoside — and also the formation of 3-0-β-D-xylopyranosyloleanolic acid 13,28-lactone are described.