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81.
82.
Yu Suzuki Takanori Higashi Takahiro Yamamoto Hideyasu Okamura Takehiro K. Sato Tetsuo Asakura 《Molecules (Basel, Switzerland)》2022,27(2)
Spider dragline silk is a biopolymer with excellent mechanical properties. The development of recombinant spider silk protein (RSP)-based materials with these properties is desirable. Formic acid (FA) is a spinning solvent for regenerated Bombyx mori silk fiber with excellent mechanical properties. To use FA as a spinning solvent for RSP with the sequence of major ampullate spider silk protein from Araneus diadematus, we determined the conformation of RSP in FA using solution NMR to determine the role of FA as a spinning solvent. We assigned 1H, 13C, and 15N chemical shifts to 32-residue repetitive sequences, including polyAla and Gly-rich regions of RSP. Chemical shift evaluation revealed that RSP is in mainly random coil conformation with partially type II β-turn structure in the Gly-Pro-Gly-X motifs of the Gly-rich region in FA, which was confirmed by the 15N NOE data. In addition, formylation at the Ser OH groups occurred in FA. Furthermore, we evaluated the conformation of the as-cast film of RSP dissolved in FA using solid-state NMR and found that β-sheet structure was predominantly formed. 相似文献
83.
Ir(III)‐Catalyzed C7‐Position‐Selective Oxidative CH Alkenylation of Indolines with Alkenes in Air
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An efficient method for C7‐position‐selective alkenylation of N‐substituted indolines with alkenes is reported. Various 7‐alkenylindolines were obtained in moderate to excellent yields in air in the presence of catalytic amounts of [Cp*IrCl2]2, AgOTf, and Cu(OAc)2. The protocol relies on the use of a carbonyl or carbamoyl group on the nitrogen atom of indoline as a directing group and is potentially applicable to the synthesis of 7‐alkenylindoles and 7‐alkylindoles. 相似文献
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Masanori Miura Takanori Koike Tsukasa Ishihara Fukushi Hirayama Shuichi Sakamoto Minoru Okada 《合成通讯》2013,43(24):3809-3820
A one‐pot synthetic procedure for 2,2′‐disubstituted biaryls was developed via a Suzuki cross‐coupling reaction of aryl triflates in a biphasic solvent system. The effects of various bases and solvents were investigated. Results showed that the Na2CO3–toluene/H2O combination gave the highest yields. 相似文献
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Ohkita M Kawano M Suzuki T Tsuji T 《Chemical communications (Cambridge, England)》2002,(24):3054-3055
The crystallization of 2,4,6-triethynyl-1,3,5-triazine (2) leads to a pi-stacked layered structure of a C(sp)-H...N hydrogen-bonded unique hexagonal network structure, which may be regarded as a supramolecular analogue of a hitherto unknown graphyne network: in-plane intermolecular interactions are short and linear H...N contacts (2.31 and 2.34 A) and the interlayer separation is 3.23 A. 相似文献
90.
Tagmatarchis N Georgakilas V Prato M Shinohara H 《Chemical communications (Cambridge, England)》2002,(18):2010-2011
Electrophilic addition of chloroform to SWNTs followed by hydrolysis resulted in the addition of hydroxy groups to the surface of the nanotubes; further esterification with propionyl chloride led to the corresponding ester derivatives, which allowed us to identify their structure, also providing better solubility in organic solvents. 相似文献