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101.
Watanabe Sou Sano Yuichi Kofuji Hirohide Takeuchi Masayuki Shibata Atsuhiro Nomura Kazunori 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(3):1113-1117
Journal of Radioanalytical and Nuclear Chemistry - The extraction chromatography experiments for Am(III) and Cm(III) recovery from genuine HLLW were carried out in order to demonstrate modified 2... 相似文献
102.
Phosphine‐Catalyzed anti‐Carboboration of Alkynoates with 9‐BBN‐Based 1,1‐Diborylalkanes: Synthesis and Use of Multisubstituted γ‐Borylallylboranes 下载免费PDF全文
Ayaka Yamazaki Kazunori Nagao Dr. Tomohiro Iwai Prof. Dr. Hirohisa Ohmiya Prof. Dr. Masaya Sawamura 《Angewandte Chemie (International ed. in English)》2018,57(12):3196-3199
Trialkylphosphine organocatalysis has enabled the regioselective anti‐carboboration of alkynoates with 9‐BBN‐based 1,1‐diborylalkanes to produce secondary allylboranes with β‐alkoxycarbonyl and γ‐boryl substituents. The utility of the densely functionalized allylboranes was demonstrated by the highly diastereoselective allylation of N‐(trimethylsilyl)aldimines to produce homoallylamines containing tertiary allylborane and acrylate moieties. 相似文献
103.
Mitsunori Fukaya Shota Nagamine Dr. Taro Ozaki Yaping Liu Miina Ozeki Taro Matsuyama Dr. Kazunori Miyamoto Prof. Dr. Hirokazu Kawagishi Prof. Dr. Masanobu Uchiyama Prof. Dr. Hideaki Oikawa Dr. Atsushi Minami 《Angewandte Chemie (International ed. in English)》2023,62(44):e202308881
Mushroom terpenoids are biologically and chemically diverse fungal metabolites. Among them, melleolides are representative sesquiterpenoids with a characteristic protoilludane skeleton. In this study, we applied a recently established hot spot knock-in method to elucidate the biosynthetic pathway leading to 1α-hydroxymelleolide. The biosynthesis of the sesquiterpene core involves the cytochrome P450 catalyzing stepwise hydroxylation of the Δ6-protoilludene framework and a stereochemical inversion process at the C5 position catalyzed by short-chain dehydrogenase/reductase family proteins. The highlight of the biosynthesis is that the flavoprotein Mld7 catalyzes an oxidation-triggered double-bond shift accompanying dehydration and acyl-group-assisted substitution with two different nucleophiles at the C6 position to afford the Δ7-protoilludene derivatives, such as melleolide and armillarivin. The complex reaction mechanism was proposed by DFT calculations. Of particular importance is that product distribution is regulated by interaction with the cell membrane. 相似文献
104.
Noda N Tani H Morita N Kurata S Nakamura K Kanagawa T Tsuneda S Sekiguchi Y 《Analytica chimica acta》2008,610(2):211-216
A modified solvent microextraction with back extraction method (SME/BE) combined with high performance liquid chromatography and fluorescence detection (HPLC-FD) was developed for the determination of citalopram in human plasma. Extraction process was performed in a home-made total glass vial without using a teflon ring, usually employed in SME/BE. Citalopram was first extracted from 0.5 mL of plasma, modified with sodium hydroxide, into hexane. Back extraction step was then performed into 5.2 μL of 45 mM ammonium formate solution (pH 4) using a GC microsyringe. The extract was subsequently transferred into a liner-like vial and then injected into the HPLC system. An enrichment factor of 150 along with a good sample clean-up was obtained. The calibration curve showed linearity in the range of 1.0–130.0 ng mL−1 with regression coefficient corresponding to 0.992. This range covers therapeutic window and even lower amounts which is important in pharmacokinetic studies. Limits of detection and quantification, based on a signal to noise ratio (S/N) of 3 and 10, were 0.3 and 0.8 ng mL−1, respectively. The method was also applied for the determination of citalopram in plasma samples after oral administration of 40 mg single dose of citalopram. 相似文献
105.
Miyamoto C Suzuki K Iwatsuki S Inamo M Takagi HD Ishihara K 《Inorganic chemistry》2008,47(5):1417-1419
The rate constants for a boronate ion were determined for the first time using the reaction systems of 3-nitrophenylboronic acid (3-NO2PhB(OH)2) with ethylene glycol (EG) and propylene glycol (PG) in an alkaline solution: the rate constants (25 degrees C, I = 0.10 M) for the reactions of 3-NO2PhB(OH)3- are 1.2 M(-1) s(-1) (EG) and 1.5 M(-1) s(-1) (PG), which are at least 10(3) times smaller than those for the reactions of 3-NO 2PhB(OH)2 [1.0 x 10(4) M(-1) s(-1) (EG) and 5.8 x 10(3) M(-1) s(-1) (PG)]. 相似文献
106.
Shoma Mizutani Kenta Komori Tohru Taniguchi Kenji Monde Kouji Kuramochi Kazunori Tsubaki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(33):9705-9708
A biomimetic synthesis of naturally occurring lactams rubrobramide, flavipucine, and isoflavipucine is described. The key step is a regioselective Darzens reaction between isobutyl glyoxal and an α‐bromo‐β‐ketoamide. The construction of the core tricyclic ring system of rubrobramide was achieved by a cascade reaction in a single step from an α,β‐epoxy‐γ‐lactam. Furthermore, the absolute configuration of naturally occurring (+)‐rubrobramide was determined by vibrational circular dichroism. (±)‐Flavipucine and (±)‐isoflavipucine were synthesized from an epoxyimide, which was prepared by reaction of isobutyl glyoxal with a protected α‐bromo‐β‐ketoamide. Deprotection of the epoxyimide and formation of the pyridone ring gave (±)‐flavipucine, which was converted into (±)‐isoflavipucine by thermal isomerization. 相似文献
107.
4-(Difluoroiodo)toluene-induced domino lambda(3)-iodanation-1,4-halogen shift-ring enlargement-fluorination reaction of 5-halopentynes with a four-, five-, or six-membered carbocycle afforded the ring-expanded (E)-delta-fluoro-beta-halovinyl-lambda3-iodanes stereoselectively in high yields, probably via the intermediacy of five-membered halonium ions. Use of internal alkynes makes it possible to synthesize tetrasubstituted beta-halovinyl-lambda(3)-iodanes with defined stereochemistry. 相似文献
108.
Matsuoka D Iwata T Zikihara K Kandori H Tokutomi S 《Photochemistry and photobiology》2007,83(1):122-130
Phototropin is a blue-light photoreceptor in plants that mediates phototropism, chloroplast relocation, stomata opening and leaf expansion. Phototropin molecule has two photoreceptive domains named LOV1 (light-oxygen-voltage) and LOV2 in the N-terminus and a serine/threonine kinase domain in the C-terminus, and acts as a blue light-regulated kinase. Each LOV domain binds a flavin mononucleotide as a chromophore and undergoes unique cyclic reactions upon blue-light absorption that comprises a cysteinyl-flavin adduct formation through a triplet-excited state and a successive adduct break to revert to the initial ground state. The molecular reactions underlying the photocycle are reviewed and one of the probable molecular schemes is presented. Adduct formation alters the secondary protein structure of the LOV domains. This structural change could be transferred to the linker between the kinase domain and involved in the photoregulation of the kinase activity. The structural changes as well as the oligomeric structures seem to differ between LOV1 and LOV2, which may explain the proposed roles of each domain in the photoregulation of the kinase activity. The photoregulation mechanism of phototropin kinase is reviewed and discussed in reference to the regulation mechanism of protein kinase A, which it resembles. 相似文献
109.
110.