start-ver=1.4
cd-journal=joma
no-vol=5
cd-vols=
no-issue=17
article-no=
start-page=10207
end-page=10216
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2020
dt-pub=20200420
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Minimization of Amounts of Catalyst and Solvent in NHC-Catalyzed Benzoin Reactions of Solid Aldehydes: Mechanistic Consideration of Solid-to-Solid Conversion and Total Synthesis of Isodarparvinol B
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Attempts were made to minimize the amounts of catalyst and solvent in the NHC-catalyzed benzoin reactions of solid aldehydes. In some case, solid-to-solid conversions proceeded in the solvent-free NHC-catalyzed benzoin reactions. Even if a mixture of the substrate, N-heterocyclic carbene (NHC) precursor, and inorganic base was initially a powdery solid, the reaction did proceed at reaction temperature lower than the melting points of each compound. The solid mixture partially melted or became a slurry or suspension in the meantime. We call this solid/liquid mixture a semisolid state. The reaction giving an optically active product was faster than that giving a racemic mixture of the same product. Melting-point depression was observed for a series of mixtures of the substrate and product in different substrate/product ratios. Solvent-free solid-to-solid conversions were accelerated by the formation of a semisolid state resulting from the melting-point depression of the solid substrate accompanied by the product formation. In the case of solid substrates with high melting points, melting-point depression was useless, and the addition of a small amount of solvent was needed. The first total synthesis of isodarparvinol B was achieved via the NHC-catalyzed intramolecular benzoin reaction using a small amount of solvent as an additive.
en-copyright=
kn-copyright=

en-aut-name=IwaiKenta
en-aut-sei=Iwai
en-aut-mei=Kenta
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=OnoMasakazu
en-aut-sei=Ono
en-aut-mei=Masakazu
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=NanjoYoshiko
en-aut-sei=Nanjo
en-aut-mei=Yoshiko
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=EmaTadashi
en-aut-sei=Ema
en-aut-mei=Tadashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END

start-ver=1.4
cd-journal=joma
no-vol=11
cd-vols=
no-issue=22
article-no=
start-page=5669
end-page=5675
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2020
dt-pub=20200518
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Aluminum porphyrins with quaternary ammonium halides as catalysts for copolymerization of cyclohexene oxide and CO2: metal–ligand cooperative catalysis
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Bifunctional AlIII porphyrins with quaternary ammonium halides, 2-Cl and 2-Br, worked as excellent catalysts for the copolymerization of cyclohexene oxide (CHO) and CO2 at 120 °C. Turnover frequency (TOF) and turnover number (TON) reached 10 000 h−1 and 55 000, respectively, and poly(cyclohexene carbonate) (PCHC) with molecular weight of up to 281 000 was obtained with a catalyst loading of 0.001 mol%. In contrast, bifunctional MgII and ZnII counterparts, 3-Cl and 4-Cl, as well as a binary catalyst system, 1-Cl with bis(triphenylphosphine)iminium chloride (PPNCl), showed poor catalytic performances. Kinetic studies revealed that the reaction rate was first-order in [CHO] and [2-Br] and zero-order in [CO2], and the activation parameters were determined: ΔH‡ = 12.4 kcal mol−1, ΔS‡ = −26.1 cal mol−1 K−1, and ΔG‡ = 21.6 kcal mol−1 at 80 °C. Comparative DFT calculations on two model catalysts, AlIII complex 2′ and MgII complex 3′, allowed us to extract key factors in the catalytic behavior of the bifunctional AlIII catalyst. The high polymerization activity and carbonate-linkage selectivity originate from the cooperative actions of the metal center and the quaternary ammonium cation, both of which facilitate the epoxide-ring opening by the carbonate anion to form the carbonate linkage in the key transition state such as TS3b (ΔH‡ = 13.3 kcal mol−1, ΔS‡ = −3.1 cal mol−1 K−1, and ΔG‡ = 14.4 kcal mol−1 at 80 °C).
en-copyright=
kn-copyright=

en-aut-name=DengJingyuan
en-aut-sei=Deng
en-aut-mei=Jingyuan
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=RatanasakManussada
en-aut-sei=Ratanasak
en-aut-mei=Manussada
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=SakoYuma
en-aut-sei=Sako
en-aut-mei=Yuma
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=TokudaHideki
en-aut-sei=Tokuda
en-aut-mei=Hideki
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=MaedaChihiro
en-aut-sei=Maeda
en-aut-mei=Chihiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=HasegawaJun-ya
en-aut-sei=Hasegawa
en-aut-mei=Jun-ya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=NozakiKyoko
en-aut-sei=Nozaki
en-aut-mei=Kyoko
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

en-aut-name=EmaTadashi
en-aut-sei=Ema
en-aut-mei=Tadashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=8
ORCID=

affil-num=1
en-affil=Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo
kn-affil=

affil-num=2
en-affil=Institute for Catalysis, Hokkaido University
kn-affil=

affil-num=3
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=5
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=6
en-affil=Institute for Catalysis, Hokkaido University
kn-affil=

affil-num=7
en-affil=Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo
kn-affil=

affil-num=8
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END

start-ver=1.4
cd-journal=joma
no-vol=11
cd-vols=
no-issue=1
article-no=
start-page=11883
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2021
dt-pub=20210604
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Enhancement of protein thermostability by three consecutive mutations using loop-walking method and machine learning
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=We developed a method to improve protein thermostability, "loop-walking method". Three consecutive positions in 12 loops of Burkholderia cepacia lipase were subjected to random mutagenesis to make 12 libraries. Screening allowed us to identify L7 as a hot-spot loop having an impact on thermostability, and the P233G/L234E/V235M mutant was found from 214 variants in the L7 library. Although a more excellent mutant might be discovered by screening all the 8000 P233X/L234X/V235X mutants, it was difficult to assay all of them. We therefore employed machine learning. Using thermostability data of the 214 mutants, a computational discrimination model was constructed to predict thermostability potentials. Among 7786 combinations ranked in silico, 20 promising candidates were selected and assayed. The P233D/L234P/V235S mutant retained 66% activity after heat treatment at 60 degrees C for 30 min, which was higher than those of the wild-type enzyme (5%) and the P233G/L234E/V235M mutant (35%).
en-copyright=
kn-copyright=

en-aut-name=YoshidaKazunori
en-aut-sei=Yoshida
en-aut-mei=Kazunori
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=KawaiShun
en-aut-sei=Kawai
en-aut-mei=Shun
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=FujitaniMasaya
en-aut-sei=Fujitani
en-aut-mei=Masaya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=KoikedaSatoshi
en-aut-sei=Koikeda
en-aut-mei=Satoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=KatoRyuji
en-aut-sei=Kato
en-aut-mei=Ryuji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=EmaTadashi
en-aut-sei=Ema
en-aut-mei=Tadashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

affil-num=1
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University
kn-affil=

affil-num=3
en-affil=Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University
kn-affil=

affil-num=4
en-affil=Innovation Center, Amano Enzyme Inc.
kn-affil=

affil-num=5
en-affil=Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University
kn-affil=

affil-num=6
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END

start-ver=1.4
cd-journal=joma
no-vol=
cd-vols=
no-issue=
article-no=
start-page=
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2021
dt-pub=20211018
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Chiral exciplex dyes showing circularly polarized luminescence: extension of the excimer chirality rule
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=A series of axially chiral binaphthyls and quaternaphthyls possessing two kinds of aromatic fluorophores, such as pyrenyl, perylenyl, and 4-(dimethylamino)phenyl groups, arranged alternately were synthesized by a divergent method. In the excited state, the fluorophores selectively formed a unidirectionally twisted exciplex (excited heterodimer) by a cumulative steric effect and exhibited circularly polarized luminescence (CPL). They are the first examples of a monomolecular exciplex CPL dye. This versatile method for producing exciplex CPL dyes also improved fluorescence intensity, and the CPL properties were not very sensitive to the solvent or to the temperature owing to the conformationally rigid exciplex. This systematic study allowed us to confirm that the excimer chirality rule can be applied to the exciplex dyes: left- and right-handed exciplexes with a twist angle of less than 90 degrees exhibit (-)- and (+)-CPL, respectively.
en-copyright=
kn-copyright=

en-aut-name=TakaishiKazuto
en-aut-sei=Takaishi
en-aut-mei=Kazuto
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=MurakamiSho
en-aut-sei=Murakami
en-aut-mei=Sho
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=IwachidoKazuhiro
en-aut-sei=Iwachido
en-aut-mei=Kazuhiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=EmaTadashi
en-aut-sei=Ema
en-aut-mei=Tadashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END

start-ver=1.4
cd-journal=joma
no-vol=15
cd-vols=
no-issue=8
article-no=
start-page=707
end-page=713
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2024
dt-pub=2024
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Terpolymerizations of cyclohexene oxide, CO2, and isocyanates or isothiocyanates for the synthesis of poly(carbonate–urethane)s or poly(carbonate–thioimidocarbonate)s
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Terpolymerization of cyclohexene oxide (CHO), CO2, and aryl isothiocyanates produced poly(carbonate–thioimidocarbonate)s with gradient character, while that of CHO, CO2, and aryl isocyanates furnished poly(carbonate–urethane)s with random sequences. The former underwent partial degradation upon acid treatment or UV irradiation, while the latter was stable under the same conditions.
en-copyright=
kn-copyright=

en-aut-name=NakaokaKoichi
en-aut-sei=Nakaoka
en-aut-mei=Koichi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=MuranakaSatoshi
en-aut-sei=Muranaka
en-aut-mei=Satoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=YamamotoIo
en-aut-sei=Yamamoto
en-aut-mei=Io
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=EmaTadashi
en-aut-sei=Ema
en-aut-mei=Tadashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END

start-ver=1.4
cd-journal=joma
no-vol=14
cd-vols=
no-issue=37
article-no=
start-page=4338
end-page=4343
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2023
dt-pub=2023
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Catalytic synthesis and physical properties of CO2-based cross-linked poly(cyclohexene carbonate)s
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Bifunctional aluminum porphyrins (0.001 mol%) catalyzed the terpolymerization of cyclohexene oxide (CHO), bis(CHO), and CO2 to give cross-linked polycarbonates (CLPs) under solvent-free conditions. A small amount of bis(CHO) acted as a cross-linking agent, and the use of only 0.1 mol% bis(CHO) to CHO produced polymers of quite large sizes. The thermal and mechanical properties of CLPs could be altered by changing the structure and amount of bis(CHO), and the CLPs showed improved thermal stability and tensile strength as compared to linear poly(cyclohexene carbonate)s (PCHCs). The degradation of the CLPs was also investigated, and the selective cleavage of the cross-links was achieved by UV light irradiation to give linear PCHCs. The present study disclosed the potentials of cross-linking terpolymerization for the preparation of various CLPs with a constant CO2 content (31 wt%).
en-copyright=
kn-copyright=

en-aut-name=MaedaChihiro
en-aut-sei=Maeda
en-aut-mei=Chihiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=KawabataKenta
en-aut-sei=Kawabata
en-aut-mei=Kenta
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=NikiKaito
en-aut-sei=Niki
en-aut-mei=Kaito
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=SakoYuma
en-aut-sei=Sako
en-aut-mei=Yuma
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=OkiharaTakumi
en-aut-sei=Okihara
en-aut-mei=Takumi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=EmaTadashi
en-aut-sei=Ema
en-aut-mei=Tadashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

affil-num=1
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=5
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=6
en-affil=Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END