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We have developed reflective diffraction optical elements (DOE) for focusing monochromatic coherent radiation of 400 W terahertz Novosibirsk free-electron laser (FEL). Operational characteristics of two modifications of the refractive kinoform lenses were studied. Quasioptical Toepler system with terahertz radiation recording by a thermosensitive luminescent screen was fabricated for the examination of film and solid deformation. A system for real-time terahertz radioscopy of objects with image recording with a microbolometer matrix (MBM) was fabricated. Images of objects illuminated with a plane wave or diffuse radiation were studied with the MBM. It was shown that the speckle pattern, which appears in the second case, can be averaged by means of the scatterer rotation.

3-Ethyl substituted triterpenoids with a fragmented and 5-membered A ring were synthesized from the lupane ketoxime via the Beckmann reaction and intramolecular oxonitrile cyclization, respectively. Transformations of the triterpenic isopropylidene fragment with the formation of C(30) and C(20) modified derivatives were performed by either allylic C(30) oxidation or ozonolytic cleavage of the C(20)-C(29) double bond. Antitumor activity of the synthesized compounds was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,3-diphenyl-tetrazolium bromide test against 7 human cancer cell lines. Methyl 1-cyano-3-ethyl-3-oxo-2,3-seco-2-norlup-20(29)-en-30-al-28-oate (4), methyl 3-[1-bromoethyl]-1-cyano-3-oxo-2,3-seco-2-norlup-20(29)-en-30-al-28-oate (6), and methyl 1-cyano-3-ethyl-2-norlup-1(3),20(29)-dien-30-al-28-oate (9) were selected as compounds with highest cytotoxicity (IC50 1.38-15.91 μM).

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