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81.
Ovchinnikova I. G. Valova M. S. Matochkina E. G. Kodess M. I. Tumashov A. A. Slepukhin P. A. Fedorova O. V. Rusinov G. L. Charushin V. N. 《Russian Chemical Bulletin》2011,60(5):965-974
A new type of intramolecular cyclization of 1,5-bis[2-(E-3-oxo-3-phenylprop-1-enyl)-phenoxy]-3-oxapentane with 3-aminotriazole promoted by potassium ions was discovered. A cascade
mechanism for the formation of crownophane with 4,7-dihydro[1,2,4]triazolo[1,5-a]-pyrimidine fragment was suggested. Effects of oligooxyethylene fragment of the chalcone podand and acid-base catalysis on
the selectivity of the cyclocondensation processes and degree of oxidation of triazolopyrimidine fragments were studied. The
product structures were confirmed by IR, 1H and 13C NMR spectroscopy and X-ray diffraction study. 相似文献
82.
I. G. Ovchinnikova D. K. Nikulov E. V. Bartashevich E. G. Matochkina M. I. Kodess P. A. Slepukhin A. V. Druzhinin O. V. Fedorova G. L. Rusinov V. N. Charushin 《Russian Chemical Bulletin》2011,60(5):824-840
Specific features of crystal packings and pre-organization of diarylideneacetonyl crownophane molecules to solid-phase photochemical
transformations were studied on the basis of X-ray diffraction data using methods of simulation of molecular crystal packings.
The tendency of the most part of the synthesized macrocyclic E,E-isomers to the formation of homochiral crystals (P212121) was revealed, while (23E,26E)-11,12,14,15-tetrahydro-8H-dinaphtho-[2,1-k:1′,2′-r][1,4,7,10]tetraoxacyclononadecine-23,26-dien-25(9H)-one is prone to polymorphism. A phenomenon of solid-phase stereospecific photochemical dimerization of molecules according
to the syn-head-to-tail type without crystal destruction (single crystal—single crystal transformation) was found for one of the modifications
of this crownophane. 相似文献
83.
A. S. Shashkov D. E. Tsvetkov O. A. Lapchinskaya V. V. Kulyaeva G. B. Fedorova A. S. Trenin E. G. Gladkikh V. V. Pogozheva M. O. Makarova G. I. Orlova G. S. Katrukha N. E. Nifantiev 《Russian Chemical Bulletin》2011,60(11):2412-2417
The screening for novel antibiotic producers by selection methods revealed the Streptomyces sp. strain No. 1278 producing the antibiotic INA-1278, which exhibits antimicrobial and antifungal activities. This compound was isolated from the liquid culture by extraction with organic solvents and purified by chromatographic methods. The structure of this antibiotic was studied by mass spectrometry and 1H and 13C NMR spectroscopy. An analysis of the results of the investigation indicate that the compound INA-1278 is structurally related to the antibiotic irumamycin, which has been studied earlier. However, the novel antibiotic may differ from irumamycin in the configurations of some asymmetric centers, which were not established at the present stage of our research. 相似文献
84.
V. L. Gein N. L. Fedorova E. B. Levandovskaya M. I. Vakhrin 《Russian Journal of Organic Chemistry》2011,47(1):95-99
4-Acetyl-1-alkoxyaryl-5-aryl-3-hydroxy-2,5-dihydro-1H-pyrrol-2-ones reacted with amines to give 1-alkoxyaryl-5-aryl-4-(1-R-aminoethylidene)pyrrolidine-2,3-diones. Reactions of amines with 4-benzoyl-substituted analogs involve nucleophilic attack on the C3 atom in the heteroring to produce the corresponding 3-R-amino-1-alkoxyaryl-5-aryl-4-benzoyl-2,5-dihydro-1H-pyrrol-2-ones. Reactions of the title compounds with hydrazine hydrate, regardless on the substituent on C4, afforded 4-aryl-3-methyl(phenyl)-5-[2(4)-methoxyphenyl]-4,6-dihydropyrrolo[3,4-c]pyrazol-6-ones. 相似文献
85.
The term reactive oxygen species refers to small molecules that can oxidize, for example, nearby proteins, especially cysteine, methionine, tryptophan, and tyrosine residues. Tryptophan oxidation is always irreversible in the cell and can yield several oxidation products, such as 5-hydroxy-tryptophan (5-HTP), oxindolylalanine (Oia), kynurenine (Kyn), and N-formyl-kynurenine (NFK). Because of the severe effects that oxidized tryptophan residues can have on proteins, there is a great need to develop generally applicable and highly sensitive techniques to identify the oxidized residue and the oxidation product. Here, the fragmentation behavior of synthetic peptides corresponding to sequences recently identified in three skeletal muscle proteins as containing oxidized tryptophan residues were studied using postsource decay and collision-induced dissociation (CID) in matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF)/TOF mass spectrometry (MS) and CID in an electrospray ionization (ESI) double quadrupole TOF-MS. For each sequence, a panel of five different peptides containing Trp, 5-HTP, Kyn, NFK, or Oia residue was studied. It was always possible to identify the modified positions by the y-series and also to distinguish the different oxidation products by characteristic fragment ions in the lower mass range by tandem MS. NFK- and Kyn-containing peptides displayed an intense signal at m/z 174.1, which could be useful in identifying accordingly modified peptides by a sensitive precursor ion scan. Most importantly, it was always possible to distinguish isomeric 5-HTP and Oia residues. In ESI- and MALDI-MS/MS, this was achieved by the signal intensity ratios of two signals obtained at m/z 130.1 and 146.1. In addition, high collision energy CID in the MALDI-TOF/TOF-MS also permitted the identification of these two isomeric residues by their v- and w-ions, respectively. 相似文献
86.
E. N. Andryukhina O. A. Fedorova Yu. V. Fedorov M. A. Panfilov H. Ihmels M. V. Alfimov S. P. Gromov 《Russian Chemical Bulletin》2005,54(5):1328-1330
The photoinduced electrocyclic transformation of 15-crown-5-containing 2-styrylbenzothiazoles into condensed benzothiazoloquinoline
derivatives was discovered. The process is accompanied by the formation of a C-N bond and elimination of a hydrogen atom.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1290–1292, May, 2005. 相似文献
87.
E. E. Antonov L. G. Dedenko A. A. Kirillov T. M. Roganova G. F. Fedorova E. Yu. Fedunin 《Physics of Atomic Nuclei》2002,65(10):1843-1846
The attenuation length for the charged-particle density at a distance of 600 m from the shower axis may differ from that adopted in experimental investigations by 40–50%. This casts some doubt on experimental estimates previously obtained for the energy of primary-cosmic-ray particles in the region of ultrahigh energies. 相似文献
88.
S. P. Gromov O. A. Fedorova A. L. Vedernikov V. V. Samoshin M. V. Alfimov 《Russian Chemical Bulletin》1993,42(5):960-961
Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, p. 996, May, 1993. 相似文献
89.
Fedorova I. V. Krishtal S. P. Kiselev M. G. Safonova L. P. 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(1):S7-S13
Ab initio calculations weere used to obtain the characteristics of the most stable configurations of the (H3PO4)2, DMFA-H3PO4, and DMFA-(H3PO4)2 complexes in a vacuum. The changes in the geometric parameters in this series of complexes were analyzed and the energies of intermolecular interactions were estimated. The DMFA-(H3PO4)2 complex was found to be most stable. It was established that the hydrogen bond between the DMFA and H3PO4 molecules is formed with the participation of both lone pairs of the oxygen atom of the DMFA molecule. 相似文献
90.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 973–974, April, 1991. 相似文献