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961.
Kazuki Ogata Daisuke Sasano Tomoya Yokoi Dr. Katsuhiro Isozaki Ryota Yoshida Dr. Toshio Takenaka Dr. Hirofumi Seike Dr. Tetsuya Ogawa Prof. Dr. Hiroki Kurata Dr. Nobuhiro Yasuda Prof. Dr. Hikaru Takaya Prof. Dr. Masaharu Nakamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12356-12375
The NCN‐pincer Pd‐complex‐bound norvalines Boc‐D /L ‐[PdCl(dpb)]Nva‐OMe ( 1 ) were synthesized in multigram quantities. The molecular structure and absolute configuration of 1 were unequivocally determined by single‐crystal X‐ray structure analysis. The robustness of 1 under acidic/basic conditions provides a wide range of N‐/C‐terminus convertibility based on the related synthetic transformations. Installation of a variety of functional groups into the N‐/C‐terminus of 1 was readily carried out through N‐Boc‐ or C‐methyl ester deprotection and subsequent condensations with carboxylic acids, R1COOH, or amines, R2NH2, to give the corresponding N‐/C‐functionalized norvalines R1‐D /L ‐[PdCl(dpb)]Nva‐R2 2 – 9 . The dipeptide bearing two Pd units 10 was successfully synthesized through the condensation of C‐free 1 with N‐free 1 . The robustness of these Pd‐bound norvalines was adequately demonstrated by the preservation of the optical purity and Pd unit during the synthetic transformations. The lipophilic Pd‐bound norvalines L ‐ 2 , Boc‐L ‐[PdCl(dpb)]Nva‐NH‐n‐C11H23, and L ‐ 4 , n‐C4H9CO‐L ‐[PdCl(dpb)]Nva‐NH‐n‐C11H23, self‐assembled in aromatic solvents to afford supramolecular gels. The assembled structures in a thermodynamically stable single crystal of L ‐ 2 and kinetically stable supramolecular aggregates of L ‐ 2 were precisely elucidated by cryo‐TEM, WAX, SAXS, UV/Vis, IR analyses, and single‐crystal X‐ray crystallography. An antiparallel β‐sheet‐type aggregate consisting of an infinite one‐dimensional hydrogen‐bonding network of amide groups and π‐stacking of PdCl(dpb) moieties was observed in the supramolecular gel fiber of L ‐ 2 , even though discrete dimers are assembled through hydrogen bonding in the thermodynamically stable single crystal of L ‐ 2 . The disparate DSC profiles of the single crystal and xerogel of L ‐ 2 indicate different thermodynamics of the molecular assembly process. 相似文献
962.
我们利用具有不同对称性的同分异构体,通过改变分子间氢键网络,操控单链磁体行为,成功合成了2 例化合物:[NiⅡ(L1)][FeⅢ(Tp)(CN)3]2·3.5H2O (1)和[NiⅡ(L2)][FeⅢ(Tp)(CN)3]2·3H2O (2),其中Tp=hydrotris(pyrazolyl)borate,L1=3,4-bis(1H-imid-azol-1-yl)thiophen,L2=1,2-bis(1H-imidazol-1-yl)thiophen)。磁性研究表明,1和2表现为具有不同矫顽场的单链磁体行为。1的矫顽场为8.41 kOe,而2的矫顽场为3.84 kOe。 相似文献
963.
Iwai Takahiro Inoue Hiroki Kakegawa Ken Ohrui Yasuhiko Nagoya Tomoki Nagashima Hisayuki Miyahara Hidekazu Chiba Koichi Seto Yasuo Okino Akitoshi 《Plasma Chemistry and Plasma Processing》2020,40(4):907-920
Plasma Chemistry and Plasma Processing - High-efficiency decomposition technology for volatile chemical warfare agent sarin was developed using a dielectric-barrier discharge (DBD). The power... 相似文献
964.
Kie Oyama Jianlin Han Hiroki Moriwaki Vadim A. Soloshonok Hiroyuki Konno 《Helvetica chimica acta》2020,103(7):e2000077
Reported here is the asymmetric synthesis of N-Boc-protected (2S,3S)-3-amino-2-hydroxyoctadecanoic acid, a component of ralstonin A and ralstoamide A. Key synthetic steps include alkylation of chiral Ni(II) complex of glycine Schiff base, conversion of COOH to keto acid (CO−COOH) and reduction of the carbonyl group to generate α-hydroxy functionality. The structure and absolute configuration of (2S,3S)-N-Boc-3-amino-2-hydroxyoctadecanoic acid was shown to be identical to that of the naturally occurring compound. 相似文献
965.
Highly Efficient Chiral Resolution of dl‐Arginine by Cocrystal Formation Followed by Recrystallization under Preferential‐Enrichment Conditions
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Dr. Sekai Iwama Kazunori Kuyama Yuko Mori Dr. Kochunnoonny Manoj Dr. Rajesh G. Gonnade Dr. Katsuaki Suzuki Dr. Colan E. Hughes P. Andrew Williams Prof. Kenneth D. M. Harris Dr. Stéphane Veesler Dr. Hiroki Takahashi Prof. Hirohito Tsue Prof. Rui Tamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10343-10350
An excellent chiral symmetry‐breaking spontaneous enantiomeric resolution phenomenon, denoted preferential enrichment, was observed on recrystallization of the 1:1 cocrystal of dl ‐arginine and fumaric acid, which is classified as a racemic compound crystal with a high eutectic ee value (>95 %), under non‐equilibrium crystallization conditions. On the basis of temperature‐controlled video microscopy and in situ time‐resolved solid‐state 13C NMR spectroscopic studies on the crystallization process, a new mechanism of phase transition that can induce preferential enrichment is proposed. 相似文献
966.
967.
Reaction of β-aminothiocarbonyl-α-methylthioenamines (3a-d) derived from ketene-S, N-acetal (1) with benzamidine and guanidine gave 4-arylamino-pyrimidines (4a-d and 5a-d), respectively. 相似文献
968.
9‐Fluorenone (1) smoothly reacts with phenoxyethanol (2) in the presence of Al3+‐montmorillonite catalyst and 3‐mercaptopropionic acid as a cocatalyst under microwave irradiation at 160°C for 10 min to give 9,9‐bis[4‐(2‐hydroxyethoxy)phenyl]fluorene (3) in 81% yield, which was much higher than the yield of 33% obtained by conventional heating using an oil bath. A similar acceleration effect of microwave irradiation was observed in other metal‐cation‐exchanged montmorillonite catalysts as well. 相似文献
969.
Takashi Tomioka Yusuke Takahashi Toshihide Maejima Yuki Yabe Hiroki Iwata Mark T. Hamann 《Tetrahedron letters》2013
Starting from natural d-mannose, a C(42–63) B-ring tetrahydropyran fragment in karlotoxin 2 has been prepared via a common THP intermediate in a concise manner. E-Selective Julia–Kocienski olefination efficiently assembled a C(51–63) chlorodiene subunit and a C(42–50) tetrahydropyran segment. 相似文献
970.
Three types of donor-acceptor-substituted bithiophene and terthiophene compounds were studied as dichroic dyes, which were dissolved in liquid crystals. These compounds were found to have large absorption coefficients, high dichroic ratios, excellent hues, and to be very attractive for guest-host-type liquid crystal displays. They also showed good solvatochromic behaviour in liquid crystal and cyclohexane solutions. These properties were found to be closely related to the solubilities of these compounds in liquid crystals. One donor-acceptorsubstituted bithiophene was found to behave as a polarity indicator in various kinds of liquid crystal. 相似文献