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261.
Ricardo ABREU-BLAYA Juan BORY-REYES Fred BRACKX Hennie DE SCHEPPER Frank SOMMEN 《数学学报(英文版)》2012,(11)
A Hilbert transform for Hlder continuous circulant (2 × 2) matrix functions, on the d-summable (or fractal) boundary Γ of a Jordan domain Ω in R2n , has recently been introduced within the framework of Hermitean Clifford analysis. The main goal of the present paper is to estimate the Hlder norm of this Hermitean Hilbert transform. The expression for the upper bound of this norm is given in terms of the Hlder exponents, the diameter of Γ and a specific d-sum (d d) of the Whitney decomposition of Ω. The result is shown to include the case of a more standard Hilbert transform for domains with left Ahlfors-David regular boundary. 相似文献
262.
263.
Synthesis and Polymerization of the Organometallic Monomer Series Based on Cymantrenylethyl Acrylate
{η5 -C5H4[CH(CH3)OC(O)CH = CH2])Mn(CO)3, {η5—C5[CH-(CH3)OC(O)C(CH3)=CH2]]Mn(CO)3, and {η5—C5H4[CH(CH3)-OC(O)CH=C(CH3)2])Mn(CO)3 were synthesized (63, 57, and 51%, respectively) from {η5—C5H4[CH(CH3)OH])Mn(CO)3, toluene-sulfonic acid, and the acrylic, methacrylic, and dimethylacrylic acids, and from (η5-C5H4[CH(CH3)OH]}Mn(CO)3, pyridine, and the acrylic, methacrylic, and dimethylacrylic acyl chlorides [26, 48, and 25% (impure), respectively]. No product was obtained when NaH was used as the base in the latter method. The acrylate and methacrylate monomers were bulk homopolymerized at 65°C with AIBN (75% yield, Mn = 88,550 g/mol; 78% yield, Mn = 349,350 g/mol, respectively). The dimethylacrylate did not polymerize under these conditions. The polymers lost vinylcymantrene upon heating to 257 and 279°C, respectively. The polymers did not exhibit a clear Tg but were observed to soften at 85 and 160°C, respectively, and they could be pulled into fibers. 相似文献
264.
Yan Li Dr. Kazuki Fukushima Dr. Daniel J. Coady Dr. Amanda C. Engler Dr. Shaoqiong Liu Yuan Huang Dr. John S. Cho Dr. Yi Guo Dr. Lloyd S. Miller Dr. Jeremy P. K. Tan Dr. Pui Lai Rachel Ee Dr. Weimin Fan Prof. Yi Yan Yang Dr. James L. Hedrick 《Angewandte Chemie (International ed. in English)》2013,52(2):674-678
265.
Methyl acetoacetate and 2,4-pentanedione dianions were condensed with aldehydes and ketones to afford a 1,3,5-trioxygenated carboskeleton. Intramolecular cyclization of the aldol adducts delivered the title compounds in good yield. 相似文献
266.
Two readily available and different quaternary ammonium salts have been prepared by the alkylation of vinamidinium salt reduction products. These salts have been successfully converted to 2-aryl-1-cyano-1-propenes and this methodology represents a clean and efficient procedure for the construction of such systems. 相似文献
267.
The synthesis of 4-dimethylmethoxysilyl-2,6-diethylani-line (1) from 2,6-diethylaniline (2) is described. An intermediate in the process, disilazane 5 appears to be the first 2,6-dialkylaniline to be protected with 1,1,5,5-tetramethyl-1,4-dichlorodisilethylene (4). 相似文献
268.
A convenient and efficient four step synthesis of 2-methyl-5-(methylthio)benzothiazole is presented. 相似文献
269.
R. Bryan Miller 《合成通讯》2013,43(5):273-280
One of the most challenging aspects of the synthesis of gibberellic acid2 and structurally related compounds such as steviol3 is the construction of the bicyclo[3.2.1]octane system with the unusual features of an exocyclic methylene group adjacent to a bridgehead tertiary hydroxyl group. In gibberellic acid this structural feature comprises the C, D ring system, which is fused to the five-membered B ring. 相似文献
270.