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181.
Yuta Ito Misaki Matsuo Kazuki Yamamoto Wakana Yamashita Takashi Osawa Yoshiyuki Hari 《Tetrahedron》2018,74(47):6854-6860
A practical and operationally simple post-synthetic modification of oligonucleotides containing 5-trifluoromethylpyrimidine bases is described. Trifluoromethyl group was used as a post-synthetic precursor and 5-trifluoromethylpyrimidine bases within oligonucleotides were converted into the corresponding 5-carboxy-, 5-cyano-, 5-amidinyl-, and 5-carbamoyl derivatives by treatment with an alkaline solution and amines. Moreover, post-synthetic treatment of fully protected and controlled pore glass (CPG)-attached oligonucleotides proceeded successfully with the simultaneous removal of all protecting groups, cleavage from CPG, and conversion of the trifluoromethyl group to afford the corresponding modified oligonucleotides. 相似文献
182.
Kaku Uehara Yoshiyuki Ohashi Makoto Tanaka 《Journal of polymer science. Part A, Polymer chemistry》1977,15(3):707-717
The binary system of bis(acetylacetonato)metal(II) [M(acac)2] and chloral induced the polymerization of chloral [M = Mn(II), Co(II), Mg(II), and Cu(II)], the ring-opening polymerization of styrene oxide [M = Co(II) and Mg(II)], and the radical polymerization of methyl methacrylate [M = Mn(II) and Co(II)]. The similar order of activity of M(acac)2 as the catalyst for the polymerization of chloral and for the aldol reaction of chloral with acetylacetone, the deactivation of the catalyst by the introduction of a substituent at the 3-position of M(acac)2, the presence of saturated β-diketone at the end of the polymer of chloral and that of styrene oxide, and the visible light spectral data supporting the formation of the β-ketoalcoholate intermediate in the binary system of Co(acac)2 and chloral are all experimental findings which suggest that M(acac)2 is subject to the aldol addition by chloral at the 3-position of the chelated acetylacetone and that the resultant β-ketoalcoholate is a common active species for these polymerizations. 相似文献
183.
Normorphine-3- and -6-glucuronides were synthesized, and their analgesic effects were examined. Normorphine-3-glucuronide was obtained by condensation of normorphine with acetobromoglucuronate in the presence of sodium hydroxide in acetone. On the other hand, normorphine-6-glucuronide was synthesized by condensing N,O3-biscarbobenzoxynormorphine with acetobromoglucuronate in the presence of silver carbonate, and removing the protecting groups from the resultant reaction product by catalytic hydrogenation and solvolysis with sodium methoxide and barium hydroxide. The analgesic effect of normorphine-6-glucuronide (ED50 0.036 nmol/mice) was 125-fold more potent than that of normorphine in mice injected i.c.v. Normorphine-3-glucuronide was shown to be 37% effective at a dose of 2 nmol/mice, but induced convulsion at higher doses when given by i.c.v. injection. 相似文献
184.
Itaru SatoKousuke Kadowaki Hiroki UrabeJong Hwa Jung Yoshiyuki OnoSeiji Shinkai Kenso Soai 《Tetrahedron letters》2003,44(4):721-724
Highly enantiomerically enriched (up to 96-97% ee) 5-pyrimidyl alkanol was obtained by the addition of diisopropylzinc to pyrimidine-5-carbaldehyde in the presence of the artificially designed chiral inorganic material, right- and left-handed helical silica. 相似文献
185.
Hojo H Matsumoto Y Nakahara Y Ito E Suzuki Y Suzuki M Suzuki A Nakahara Y 《Journal of the American Chemical Society》2005,127(39):13720-13725
Peptide thioester corresponding to a MUC2 tandem repeat unit, which retains seven GalNAc moieties, was prepared by the Fmoc method followed by the low TfOH treatment to remove benzyl groups at the carbohydrate portions. The glycosylated peptide thioester was then consecutively joined by the activation of a thioester group by silver ions to obtain a MUC2 tandem repeat model composed of 141 amino acids with 42 GalNAc moieties. 相似文献
186.
187.
The metastable intermediate product, CIONO, which is formed from gaseous CINO and Cl2O at about 203 K, has been detected by microwave spectroscopy. The rotational constants and the inertial defects for the 35Cl and 37Cl species establish that the observed spectrum is that of planar cis CIONO. 相似文献
188.
Shannon Haymond Jerzy K. Zak Yoshiyuki Show James E. Butler Gerald T. Babcock Greg M. Swain 《Analytica chimica acta》2003,500(1-2):137-144
The spectroelectrochemical responsiveness of an optically transparent diamond electrode (OTE) toward ferrocene was investigated. A freestanding, mechanically polished, boron-doped diamond disk (0.38 mm thick and 8 mm in diameter) served as the OTE for UV-Vis transmission spectroelectrochemical measurements. A specially designed, thin-layer spectroelectrochemical cell was constructed for the measurements in which ferrocene was electrooxidized to ferricinium ion via a one-electron redox reaction. The oxidation reaction product was spectroscopically monitored in the ultraviolet (λ=252, 285 nm) region of the electromagnetic spectrum. Well-defined and highly stable spectroelectrochemical responses were observed for this type of diamond OTE. The results indicate that diamond is a useful OTE material for spectroelectrochemically studying nonaqueous redox reactions. 相似文献
189.
Topological particle field theory,general coordinate invariance and generalized Chern-Simons actions
We show that recently proposed generalized Chern-Simons action can be identified with the field theory action of a topological point particle. We find the crucial correspondence which makes it possible to derive the field theory actions from a special version of the generalized Chern-Simons actions. We provide arguments that the general coordinate invariance in the target space and the flat connection condition as a topological field theory can be accommodated in a very natural way. We propose series of new gauge invariant observables. 相似文献
190.
Kojima Y Fujita T Ona EP Matsuda H Koda S Tanahashi N Asakura Y 《Ultrasonics sonochemistry》2005,12(5):359-365
Sonochemical degradation of MCPA ((4-chloro-2-methylphenoxy) acetic acid) in dilute aqueous solutions was studied using ultrasound with a frequency of 500 kHz. The effect of gas atmosphere on MCPA degradation was investigated in nitrogen (N(2)), air (O(2)/N(2)), oxygen (O(2)), argon (Ar) and Ar/O(2) (60/40% v/v) atmospheres. For sonochemical degradation of MCPA in N(2), air (O(2)/N(2)), O(2) and Ar atmospheres, the rate enhancement of MCPA decomposition by sonolysis was found to be more effective in an O(2)-enriched atmosphere compared to Ar atmosphere. It was considered that a higher amount of oxidants was formed in a higher O(2) partial pressure, which accelerated MCPA decomposition in a radical reaction system. On the other hand, both dechlorination and total organic carbon (TOC) removal rates were higher in Ar atmosphere, compared to those in O(2)/N(2) atmosphere. It was found that, MCPA was most effectively decomposed by sonication in Ar/O(2) (60/40% v/v) atmosphere, with higher rates of decomposition, dechlorination and TOC removal. 相似文献