A new synthesis of nitroketene aminals

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, p. 2660, November, 1990.     

Ecdysteroids of a culture of tissues and cells ofAjuga turkestanica

The possibility has been studied of obtaining ecdysteroids — ecdysterone and turkesterone — with the aid of a culture of the tissues and cells of the plantAjuga turkestanica. Conditions have been selected under which the yield of ecdysteroids in the culture of tissues and cells is comparable with amounts of the same substances in the organs of the whole plant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–52, January–February, 1990.     

Synthesis of aza-, oxa-, and thiabicyclo[3.1.0]hexane heterocycles from a common synthetic intermediate

[reaction: see text] An efficient and stereospecific approach to the synthesis of structurally constrained aza-, oxa-, and thiabicyclo[3.1.0]hexane heterocycles has been achieved through application of the intramolecular cyclopropanation reaction of diazoacetates. The various constrained heterocycles (X = N, O, or S) are conveniently prepared from a common diol intermediate accessible from readily available cinnamyl alcohols. Application of the methodology to the synthesis of conformationally constrained oxazolidinone antibacterials is also discussed.     

35Cl NQR study of CCl3 reorientations in the carbonyl-containing derivatives of 3,3,3-trichloropropene

Temperature dependences of³⁵Cl NQR frequencies and spin-lattice relaxation times were measured for the CCl₃ groups of compounds CCl₃CH=CHR and CCl₃CH=CR₂ with R=COCH₃ and COOCH₃. The activation energies of CCl₃ reorientations reflect the significant contribution of intermolecular steric interactions to the value of the potential barrier hindering these reorientations. In the CCl₃CH=CHCOCH₃ crystal, the reorientations of the CCl₃ group are hindered more than those of the molecule as a whole. Perm State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 2, pp. 54–60, March–April, 1994. Translated by L. Smolina     

Apparent two-dimensional behavior of TiO2 nanotubes revealed by light absorption and luminescence

Optical absorption and photoluminescence (PL) properties of colloidal TiO(2) nanotubes, produced by the alkali hydrothermal method, were studied at room temperature in the range 300-700 nm. Nanotubes having an internal diameter in the range 2.5-5 nm have very similar optical properties, in contrast to the expected behavior for quasi-1-D systems. This is explained by the complete thermal smearing of all 1-D effects, due to the large effective mass of charge carriers in TiO(2), resulting in an apparent 2-D behavior of TiO(2) nanotubes.