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en: Concentration-dependence of specific rotation of optically active glycerol analogues and structurally related compounds: The significance of intermolecular hydrogen bonding

en: Specific rotation of optically active glycerol analogues, (S)-3-(benzyloxy)propane-1,2-diol [(S)-1], (S)-3-methoxypropane-1,2-diol [(S)-6] and (S)-3-phenoxypropane-1,2-diol [(S)-13], changed its sign from (+) to () with increasing concentration in CHCl3, whereas no significant concentration-dependent change was observed in MeOH. The 1H NMR spectrum of (S)-1 showed concentration-dependent changes of the chemical shift in CDCl3. Intermolecular interaction by OHOH hydrogen bonds was suggested by single crystal X-ray crystallography of (S)-13. The concentration-dependent changes of specific rotation of (S)-1, (S)-6, and (S)-13 in CHCl3 can therefore be presumed to be due to self-assembly of these compounds via intermolecular hydrogen bonding at high concentration. The remarkable concentration-dependent changes in specific rotation were also observed to occur in the compounds with related chemical structures, such as (S)-3-hydroxy-4-methoxy-4-oxobutanoic acid [(S)-10], (S)-1-[(2-methylpropan-2-yl)oxycarbonyl]pyrrolidine-2-carboxylic acid [Boc-L-Pro-OH, (S)-14], (R)-3-hydroxy-4,4-dimethylhydrofran-2(3H)-one [(R)-15], (R)-tetrahydrofuran-2-carboxylic acid [(R)-16], (S)-3-methyl-2-[(2-methylpropan-2-yl)oxycarbonylamino]butanoic acid [Boc-L-Val-OH, (S)-17], (R)-oxiran-2-ylmethanol [(R)-18], and (4S)-4-isopropyloxazolidin-2-one [(S)-19]. The existence of intermolecular interaction by C=OHO hydrogen bonds was suggested by single crystal X-ray crystallography of (S)-10, (S)-13, and (S)-14. Thus, this series of chiral compounds have multiple functional groups in appropriate positions that serve as hydrogen-bond donors and/or acceptors, resulting in significant concentration-dependent changes of specific rotation.

en: Results in Chemistry

ja: Results in Chemistry


en: Synthesis of Novel Phosphorus-Substituted Stable Isoindoles by a Three-Component Coupling Reaction of ortho-Phthalaldehyde, 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-Oxide, and Primary Amines

en: A three-component coupling reaction of ortho-phthalaldehyde, 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide, and various primary amines readily afforded novel phosphorus-substituted stable isoindoles in good to excellent yields. The importance of the reversible ring-opening of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide by methanolysis in the three-component coupling reaction became apparent.

en: SynOpen

ja: SynOpen


en: Efficient One-Pot, Three-Step Synthesis of 1,2,3,5-Tetrasubstituted Pyrroles via Aza-Michael Addition of Methyl 3-Iminoacrylates

en: An efficient one-pot, three-step procedure for the aza-Michael addition of methyl 3-iminoacrylates with secondary amines followed by intramolecular cyclization and silylation successfully afforded novel 1,2,3,5-tetrasubstituted pyrroles in high yields.

en: Heterocycles

ja: Heterocycles


en: Synthesis of Novel 2,3-Disubstituted Thiophenes via Tandem Thia-Michael/Aldol Reaction of Allenyl Esters

en: A tandem thia-Michael/aldol reaction of allenyl esters and mercaptoacetaldehyde in the presence of triethylamine provided 2,3,4-trisubstituted tetrahydrothiophenes. Novel 2,3-disubstituted thiophenes were obtained in high yield by the subsequent dehydration of the 2,3,4-trisubstituted tetrahydrothiophenes using p-toluenesulfonic acid monohydrate as an effective catalyst.


en: Catalytic Asymmetric Ring-Opening of σ-Symmetric Cyclic Carbonates with Chiral Sulfonamide-Amine Catalysts

en: Enantioselective ring-opening of σ-symmetric six-membered cyclic carbonates with benzyl alcohol catalyzed by 20 mol% of chiral amino sulfonamide catalysts afforded chiral acyclic carbonates in up to 79% ee.


en: Synthesis of Three Stereoisomers of Erythrochelin, a Hydroxamate-Type Tetrapeptide Siderophore from Saccharopolyspora erythraea

en: Details of the synthesis of three stereoisomers of erythrochelin, a hydroxamate-type tetrapeptide siderophore produced by Saccharopolyspora erythraea, were described. Both enantiomers of protected δ-N-hydroxyornithine were used as key intermediates in the synthesis of stereoisomers of erythrochelin containing a (3S,6S)-3,6-disubstituted-2,5-diketopiperazine ring. From comparisons of 1H and 13C NMR spectra, neither of stereoisomers provided a match for the erythrochelin spectral data, and the absolute configuration of erythrochelin was unambiguously reconfirmed to be (R,R,S,S).


en: Synthesis of Sterically Protected Isoindoles from ortho-Phthalaldehyde

en: o-Phthalaldehyde (OPA) reacts with O-protected tris(hydroxyalkyl)aminomethanes in the presence of 1-propanethiol to afford a novel class of stable isoindoles. Steric protection provided by the bulkiness of C 3-symmetric primary amines derived from tris(hydroxymethyl)aminomethane could be significant for the stabilization of 1-alkylthio-2-alkyl-substituted isoindoles derived from OPA. A plausible reaction mechanism is proposed to explain the formation of the isoindole and an isoindolin-1-one by-product.


en: Synthesis of Fluorine-Containing Analogues of 1-Lysoglycerophospholipids via HornerWadsworthEmmons Reaction

en: An efficient method of synthesizing fluorine-containing analogues of 1-lysoglycerophospholipids (1-LPLs) by introducing a palmitoyl moiety starting from bis(2,2,2-trifluoroethyl)phosphonoacetate (StillGennari reagent) is described. The method effectively employs HornerWadsworthEmmons reagents as masked 1-LPL derivatives to prepare a series of analogues of 1-lysophosphatidic acid (1-LPA), 1-lysophosphatidylethanolamine (1-LPE), and 1-lysophosphatidylcholine (1-LPC).

en: Synthesis

ja: Synthesis


en: Enzymatic Synthesis of Chiral P-Stereogenic Phosphonoacetates

en: In this data article, we describe the enzymatic kinetic resolution of a series of racemic mixed phosphonoacetates, which were successfully prepared from methyl bis(2,2,2-trifluoroethyl)phosphonoacetate (Still-Gennari reagent) by alcoholysis with -symmetrical secondary alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Porcine liver esterase (PLE)-catalyzed kinetic resolution of some of these racemic mixed phosphonoacetates proceeded in a highly stereoselective manner to furnish the chiral P-stereogenic phosphonoacetates (up to > 99% ee).

en: Chemical Data Collections

ja: Chemical Data Collections


en: Synthesis of Erythrochelin: A Hydroxamate-Type Siderophore from Saccharopolyspora erythraea

en: Erythrochelin, a hydroxamate-type siderophore produced by Saccharopolyspora erythraea, is synthesized for the first time. A key building block of erythrochelin containing the 2,5-diketopiperazine ring is prepared by intramolecular cyclization of the corresponding dipep- tide precursor derived from two kinds of protected -N-hydroxy-L-orni- thines. Consecutive condensation of the building block with protected D-serine and protected -N-hydroxy-D-ornithine, followed by deprotec- tion, furnishes erythrochelin.


en: Asymmetric Synthesis of cis-4a,5,8,8a-Tetrahydrophthalazin-1(2H)-one Derivatives Based on Organocatalytic Alcoholysis of Cyclic Dicarboxylic Anhydride

en: Asymmetric synthesis of optically active cis-4-phenyl-4a,5,8,8a- tetrahydrophthalazin-1(2H)-one and its N-alkylated derivatives based on an organocatalytic enantioselective alcoholysis of cyclic dicarboxylic anhydride was described.

en: Heterocycles


en: Close relationship between histamine H1 receptor-expressing neurons and CRH neurons in the mouse hypothalamic paraventricular nucleus.

en: The Journal of Physiological Sciences

ja: The Journal of Physiological Sciences


en: Synthesis of Rhodotorulic Acid and Its 1,4-Dimethylated Derivative


en: Reinvestigation of 1,3,4-Thiadiazol-2(3H)-Iminium Bromide in the Two-Step Synthesis of Imdazo[2,1-b][1,3,4]-Thiadiazoles


en: 実験動物解析装置の設計と試作 -高架式十字迷路

ja: 実験動物解析装置の設計と試作 -高架式十字迷路

en: Journal of Medical Technology

ja: 臨床検査


en: Selective ablation of histamine H1 receptor-expressing neurons in the hypothalamic paraventricular nucleus increased food intake and body weight gain.


en: Reinvestigation of the Synthesis of Isoliquiritigenin (ILG): Application of Horner-Wadsworth-Emmons Reaction and Claisen-Schmidt Condensation

en: Isoliquiritigenin [ILG, (E)-1] was readily prepared via the Horner-Wadsworth-Emmons reactions using β-ketophosphonates 5a, b. An improved protocol for the synthesis of (E)-1 via the Claisen-Schmidt condensation was also presented.

en: Chemical & Pharmaceutical Bulletin

ja: Chemical & Pharmaceutical Bulletin


en: Use of Diketopiperazines for Determining Absolute Configurations of α-Substituted Serines by 1H-NMR Spectroscopy


en: Chemoenzymatic Synthesis of α-Substituted Serines via Enantiodivergent Transformation

en: The Open Organic Chemistry Journal

ja: The Open Organic Chemistry Journal


en: 有機微量元素分析における流路系の対策と検討

ja: 有機微量元素分析における流路系の対策と検討

en: 技術支援部技術報告

ja: 技術支援部技術報告