Michiyasu Nakao, Akihito Nakamura, Shoki Yamada, Syuji Kitaike and Shigeki Sano : Concentration-dependence of specific rotation of optically active glycerol analogues and structurally related compounds: The significance of intermolecular hydrogen bonding, Results in Chemistry, Vol.7, 101415--, 2024.
(要約)
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.
Michiyasu Nakao, Akihito Nakamura, Tomoyuki Takesue, Syuji Kitaike, Hiro-O Ito and Shigeki Sano : 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, SynOpen, Vol.7, No.3, 394-400, 2023.
(要約)
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.
Michiyasu Nakao, Ken Horikoshi, Syuji Kitaike and Shigeki Sano : Efficient One-Pot, Three-Step Synthesis of 1,2,3,5-Tetrasubstituted Pyrroles via Aza-Michael Addition of Methyl 3-Iminoacrylates, Heterocycles, Vol.106, No.8, 1397-1406, 2023.
(要約)
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.
Michiyasu Nakao, Munehisa Toguchi, Ken Horikoshi, Syuji Kitaike and Shigeki Sano : Synthesis of Novel 2,3-Disubstituted Thiophenes via Tandem Thia-Michael/Aldol Reaction of Allenyl Esters, Heterocycles, Vol.104, No.2, 379-388, 2022.
(要約)
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.
Michiyasu Nakao, Tomomi Shozui, Daisuke Inoue, Takahito Ihara, Syuji Kitaike and Shigeki Sano : Catalytic Asymmetric Ring-Opening of σ-Symmetric Cyclic Carbonates with Chiral Sulfonamide-Amine Catalysts, Heterocycles, Vol.103, No.2, 1011-1022, 2021.
(要約)
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.
Michiyasu Nakao, Ayumu Adachi, Syuji Kitaike and Shigeki Sano : Synthesis of Three Stereoisomers of Erythrochelin, a Hydroxamate-Type Tetrapeptide Siderophore from Saccharopolyspora erythraea, Heterocycles, Vol.101, No.1, 347-356, 2020.
(要約)
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).
Michiyasu Nakao, Nanako Nishikiori, Akihito Nakamura, Murasaki Miyagi, Nao Shibata, Syuji Kitaike, Makoto Fukui, Hiro-O Ito and Shigeki Sano : Synthesis of Sterically Protected Isoindoles from ortho-Phthalaldehyde, SynOpen, Vol.2, No.1, 50-57, 2018.
(要約)
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.
Michiyasu Nakao, Kazue Tanaka, Syuji Kitaike and Shigeki Sano : Synthesis of Fluorine-Containing Analogues of 1-Lysoglycerophospholipids via HornerWadsworthEmmons Reaction, Synthesis, Vol.49, No.16, 3654-3661, 2017.
(要約)
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).
Shigeki Sano, Eiko Kujime, Hiroko Tanaka, Syuji Kitaike and Michiyasu Nakao : Enzymatic Synthesis of Chiral P-Stereogenic Phosphonoacetates, Chemical Data Collections, Vol.5/6, 12-20, 2016.
(要約)
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).
Michiyasu Nakao, Shunsuke Tsuji, Syuji Kitaike and Shigeki Sano : Synthesis of Erythrochelin: A Hydroxamate-Type Siderophore from Saccharopolyspora erythraea, Synthesis, Vol.48, No.23, 4149-4154, 2016.
(要約)
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.
Shigeki Sano, Masanori Kamura, Akihito Nakamura, Syuji Kitaike and Michiyasu Nakao : Asymmetric Synthesis of cis-4a,5,8,8a-Tetrahydrophthalazin-1(2H)-one Derivatives Based on Organocatalytic Alcoholysis of Cyclic Dicarboxylic Anhydride, Heterocycles, Vol.93, No.1, 391-398, 2016.
(要約)
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.
Shuhei Horio, Syuji Kitaike, Ryoji Fukabori, Takashi Ueyama and Kazuto Kobayashi : Close relationship between histamine H1 receptor-expressing neurons and CRH neurons in the mouse hypothalamic paraventricular nucleus., The Journal of Physiological Sciences, Vol.65, S293, 2015.
13.
Michiyasu Nakao, Shintaro Fukayama, Syuji Kitaike and Shigeki Sano : Synthesis of Rhodotorulic Acid and Its 1,4-Dimethylated Derivative, Heterocycles, Vol.90, No.2, 1309-1316, 2015.
S Horio, Syuji Kitaike, Y Minokoshi, N Kai, K Kobayashi, T Ueyama and H Fukui : Selective ablation of histamine H1 receptor-expressing neurons in the hypothalamic paraventricular nucleus increased food intake and body weight gain., The Journal of Physiological Sciences, Vol.62, S209, 2012.
17.
Shigeki Sano, Yoshinori Okubo, Atsushi Handa, Michiyasu Nakao, Syuji Kitaike, Yoshimitsu Nagao and Hisao Kakegawa : Reinvestigation of the Synthesis of Isoliquiritigenin (ILG): Application of Horner-Wadsworth-Emmons Reaction and Claisen-Schmidt Condensation, Chemical & Pharmaceutical Bulletin, Vol.59, No.7, 885-888, 2011.
(要約)
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.