Hexapole helicenes 1, which contain six [5]helicene substructures, were synthesized by Pd-catalyzed [2+2+2]cycloadditions of aryne precursor 6. Among the possible 20 stereoisomers, include ten pairs enantiomers, HH-1 was obtained selectively. Density functional theory (DFT) calculations identified as second most stable isomer that quantitatively isomerizes under thermal conditions into (HH-2). Both enantiomers HH-2 can be separated chiral HPLC. Single-crystal X-ray diffraction analyses...

The effects of various structured triglycerides containing medium-chain (caprylic or capric acids) and long-chain (linoleic acid) fatty acids on acid cholesterol absorption were studied in lymph-cannulated rats. A considerable portion caprylic was absorbed through the lymph duct, although to a lesser extent than linoleic acid. Capric located at 2-position 2-decanoyl-1,3-dilinoleoyl-glycerol (18:2/10:0/18:2) 2-linoleoyl-1,3-didecanoyl-glycerol (10:0/18:2/10:0), respectively, tended be more...

Three-bladed propeller-shaped triple [5]helicene was synthesized using eliminative and oxidative photocyclization reactions, which proceeded in 37 63% yields, respectively. Chromatographic purification gave a mixture of diastereomers, the PPM PMM isomers were gradually converted to thermodynamically more stable PPP MMM at room temperature. The activation parameters for racemization determined, structure determined by X-ray crystallographic analysis.

A new method has been developed for the potassium iodide-mediated oxidative photocyclization of stilbene derivatives. Compared with conventional iodine-mediated reactions, this requires shorter reaction times and affords cyclized products in yields 45–97%. This proceeds a catalytic amount iodide works an air-driven manner without addition external scavenger. The radical-mediated derivatives using TEMPO was also investigated.

We report the discovery of a new class light-sensing molecules. These light sensors are composed fluorophore oligomers assembled on DNA backbone. A combinatorial library tetrafluorophores consisting over 14 000 compounds was synthesized and screened for rapid responses toward exposure. Among most light-sensitive molecules, at least three tetramers were found to respond exposure with apparent color changes, rather than simple photobleaching.

(+)-Iso-A82775C is a proposed biosynthetic precursor of the chloropupukeananin family and an important intermediate for related natural products. The first enantioselective total synthesis (+)-iso-A82775C (18 steps, 2.2% overall yield) toward eventual biomimetic described. key steps are (1) Diels–Alder reaction 4-bromo-3-hydroxy-2-pyrone with methyl 2-chloroacrylate using cinchonine as organocatalyst (2) anti-selective Cu-mediated SN2′ to afford axially chiral vinylallene moiety.

Abstract A three‐dimensional π‐conjugated chiral cage with six [5]helicene units (a triple helicene cage) was synthesized for the first time. Taking advantage of Yamamoto coupling reaction, triflate‐substituted [5]helicene, a strained and preorganized precursor, dimerized to afford target compound. Single‐crystal X‐ray diffraction analysis revealed unique structural features cage: cage‐shaped rigid structure outer helical grooves an inner cavity. All‐ P all‐ M enantiomers were separated...

The total synthesis of pestheic acid based on an intramolecular SNAr reaction without a nitro group and the asymmetric (−)-maldoxin by catalytic enantioselective oxidative dearomatization are described. reactivity as diene in Diels–Alder is also investigated.

BackgroundThickening of the pericoronary adipose tissue (PCAT) is a proven risk factor for coronary artery disease, but it poorly understood whether PCAT stores pro-atherogenic substances with oxidized low-density lipoprotein (oxLDL) and (LDL), an anti-atherogenic substance high-density (HDL) supply them to intima.MethodsUsing immunohistochemical techniques, localization oxLDL, LDL HDL in its adjacent segments was examined 30 epicardial arteries excised from 11 human autopsy...

A 6-O-o-nitrobenzyl methylglucoside and methylmannoside were synthesized by reacting 4,6-O-o-nitrobenzylidene acetals with triethylsilane boron trifluoride etherate. 2,6-di-O-o-nitrobenzyl a 3,6-di-O-o-nitrobenzyl obtained from 2,3:4,6-di-O-o-nitrobenzylidene the same method. The photolabile sugars deprotected irradiation at 350 nm to afford methylglycosides.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNew Dendritic Caged Compounds: Synthesis, Mass Spectrometric Characterization, and Photochemical Properties of Dendrimers with α-Carboxy-2-nitrobenzyl Compounds at Their PeripherySoichiro Watanabe, Mika Sato, Shigeru Sakamoto, Kentaro Yamaguchi, Michiko IwamuraView Author Information Department Biomolecular Science Faculty Science, Toho University 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan Chemical Analysis Center, 1-33 Yayoicho,...

A facile and useful method for preparing caged DNAs was developed. The includes a caging reaction of linear dsDNA having minimal sequence protein expression with Bio-Bhc-diazo affinity separation the DNA. Effective suppression photo-mediated restoration were demonstrated.

Objectives It is generally believed that low-density lipoprotein enters the vascular wall from its lumen and oxidized (oxLDL), after which it plays an important role in atherosclerosis. Because voluminous epicardial adipose tissue a risk factor for coronary events, there possibility pericoronary (PCAT), part of tissue, acts as by supplying oxLDL to arterial wall. The present study was performed whether PCAT stores supplies Methods Localization relation plaque morphology were examined...

Chloropupukeananin, chloropupukeanolides, and chloropestolides are a family of structurally complex bioactive natural products that possess highly functionalized tricyclo[4.3.1.03,7]decane or bicyclo[2.2.2]octane skeletons. Biosynthesis the chloropupukeananin is triggered by intermolecular heterodimeric Diels–Alder reaction between maldoxin iso-A82775C; however, enzymes involved have not yet been identified. We herein report one-pot biomimetic synthesis chloropupukeanolide D. Moreover,...

In this paper, a harvestman-like hexapod walking robot named ASURA I is proposed and its leg mechanism design discussed. Modeled on harvestman in nature, the authors have introduced concept of mobile form that has long legs small body to enhance performance rough terrain. To develop relative body, special parallel link drive joints powerfully effectively I. First, we discuss problems detail: length, DOF configuration, actuator selection driving system. Then, analysis kinematics, singularity...

VCD spectroscopy was applied to allenic natural products elucidate their axial chirality. The sign and intensity of CCC antistretching signal were found be affected by substituents on the allene.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAn Endohedral Simple Enol: The First Isolation of a β-Unsubstituted Enol Utilizing Lantern-Shaped Molecular FrameworkSoichiro Watanabe, Kei Goto, Takayuki Kawashima, and Renji OkazakiView Author Information Department Chemistry, Graduate School Science University Tokyo, 7-3-1 Hongo, Bunkyo-ku Tokyo 113, Japan Cite this: J. Am. Chem. Soc. 1997, 119, 13, 3195–3196Publication Date (Web):April 2, 1997Publication History Received3 September...

Graphical Abstract

Abstract The title thioaldehyde 1 undergoes [4 + 2] cycloaddition with 2,3-dimethyl-1,3-butadiene at 160 °C and [3 cycloadditions diphenylnitrilimine mesitonitrile oxide room temperature. intermediary cycloadduct cycloreversion to give 2,4,6-tri-t-butylbenzaldehyde mesityl isothiocyanate as the final products. Oxidation of m-chloroperbenzoic acid (mCPBA) dimethyldioxirane (9) gives a mixture (E)- (Z)-isomers corresponding S-oxides (sulfines), former latter being kinetically thermodynamically...