Development of a continuous measurement system for atmospheric N2O and CO concentrations and its application to in-situ observation at Syowa Station, Antarctica

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Direct Nucleophilic Substitution of Alcohols Using an Immobilized Oxovanadium Catalyst

Direct nucleophilic substitution of alcohols with thiols or carbon nucleophiles was achieved using a mesoporous silica-supported oxovanadium catalyst (VMPS4). Benzyl and allyl alcohols were compatible in this reaction under mild conditions, affording the products in high yields. The VMPS4 catalyst showed excellent chemoselectivity toward alcohols in the presence of acid-labile functional groups, which is in contrast to that observed for the commonly used Lewis acid catalysts, which exhibit poor selectivity. The VMPS4 catalyst could be recycled by simple centrifugation, and the catalytic activity was maintained over seven cycles.This is the pre-peer reviewed version of the following article:Nishio T., Yoshioka S., Hasegawa K., et al. Direct Nucleophilic Substitution of Alcohols Using an Immobilized Oxovanadium Catalyst. European Journal of Organic Chemistry 2021, 4417 (2021), which has been published in final form at https://doi.org/10.1002/ejoc.202100569. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archivin

The Wood Odor Caused by Hand Sawing

本研究の目的は，ヒノキ集成材で製作された木製品のにおいと，その製品に使用された板材を被験者が手びきのこぎりびきする際に生じるにおいとについて，測定機による検査と官能検査とで比較することである。被験者は大学生と中学生とした。測定機での検査では，ほとんどの被験者ののこぎりびきにおいて測定されたにおいの値が木製品のそれより大変大きかった。板材の切断に要する時間が短いほどにおいの値が大きかった。官能検査でにおいの強度と快・不快度を調べると，切断に要する時間が短いほどにおいの強度が大きくなり，においの強度が大きいと快度が大きくなった。のこぎりびき中に大学生が感じたにおいの強度は，木製品各部のそれより大きかった。ヒノキ集成材を手びきのこぎりびきして生じるにおいの強度の大きさが認識された

Continuous-Flow Dynamic Kinetic Resolution of Racemic Alcohols by Lipase-Oxovanadium Cocatalysis

Higashio K, Katsuragi S, Kundu D, et al. Continuous-Flow Dynamic Kinetic Resolution of Racemic Alcohols by Lipase-Oxovanadium Cocatalysis. European journal of organic chemistry. 2020;2020(13):1961-1967.A continuous-flow dynamic kinetic resolution of racemic secondary alcohols was carried out using a single column reactor packed with a mixture of immobilized lipase and an immobilized oxovanadium species, VMPS4. As a result, optically pure esters were produced in 88-92 % yields. Problems encountered in this study were overcome by using fillers that efficiently maintained the initial distribution of the catalysts in the reactor and by using a packing method in which the mixing ratio of the two catalysts was varied in a stepwise fashion. The flow process led to an increased turnover number of each catalyst compared to those of batch reactions

Promising System for Selecting Healthy In Vitro–Fertilized Embryos in Cattle

Conventionally, in vitro–fertilized (IVF) bovine embryos are morphologically evaluated at the time of embryo transfer to select those that are likely to establish a pregnancy. This method is, however, subjective and results in unreliable selection. Here we describe a novel selection system for IVF bovine blastocysts for transfer that traces the development of individual embryos with time-lapse cinematography in our developed microwell culture dish and analyzes embryonic metabolism. The system can noninvasively identify prognostic factors that reflect not only blastocyst qualities detected with histological, cytogenetic, and molecular analysis but also viability after transfer. By assessing a combination of identified prognostic factors—(i) timing of the first cleavage; (ii) number of blastomeres at the end of the first cleavage; (iii) presence or absence of multiple fragments at the end of the first cleavage; (iv) number of blastomeres at the onset of lag-phase, which results in temporary developmental arrest during the fourth or fifth cell cycle; and (v) oxygen consumption at the blastocyst stage—pregnancy success could be accurately predicted (78.9%). The conventional method or individual prognostic factors could not accurately predict pregnancy. No newborn calves showed neonatal overgrowth or death. Our results demonstrate that these five predictors and our system could provide objective and reliable selection of healthy IVF bovine embryos

Strategies to Design Chemocatalytic Racemization of Tertiary Alcohols: State of the Art & Utilization for Dynamic Kinetic Resolution

Gröger H, Horino S, Kanomata K, Akai S. Strategies to Design Chemocatalytic Racemization of Tertiary Alcohols: State of the Art & Utilization for Dynamic Kinetic Resolution. Chemistry - A European Journal . 2024: e202304028.In this "Concepts"-article, the difficulties in racemizing tertiary alcohols are described as well as a summary of the different chemocatalytic concepts to overcome these hurdles and to pave a way for efficiently racemizing of tertiary alcohols. When combined with the enantioselective enzymatic esterification of tertiary alcohols, the racemization protocols enable a DKR to convert the racemates into enantiomerically pure esters of tertiary alcohols, which are of high interest in the field of pharmaceutically active products. Very recently, various research groups have succeeded in solving the challenging task of identifying suitable chemocatalysts for an efficient racemization of tertiary alcohols and simultaneously suppressing unwanted dehydration side-reactions. It is noteworthy that such methods are based on different, complementary catalysis concepts. Besides Bronsted acids, oxovanadium catalysts as well as piperidine as a representative of an organocatalyst have been found to be useful for the racemization of each type of alcohols. The latter two types of catalysts also turned out to be compatible with lipase-catalyzed kinetic resolution, thus leading to the first two examples of a proof-of-concept for chemoenzymatic DKR of tertiary alcohols. © 2024 Wiley‐VCH GmbH

Lipase-catalyzed dynamic kinetic resolution of C 1 - and C 2 -symmetric racemic axially chiral 2,2′-dihydroxy-1,1′-biaryls

We have discovered that the racemization of configurationally stable, axially chiral 2,2′‐dihydroxy‐1,1′‐biaryls proceeds with a catalytic amount of a cyclopentadienylruthenium(II) complex at 35–50 °C. Combining this racemization procedure with lipase‐catalyzed kinetic resolution led to the first lipase/metal‐integrated dynamic kinetic resolution of racemic axially chiral biaryl compounds. The method was applied to the synthesis of various enantio‐enriched C1‐ and C2‐symmetric biaryl diols in yields of up to 98 % and enantiomeric excesses of up to 98 %, which paves the way for new developments in the field of asymmetric synthesis

Construction of Functionalized ortho-Naphthoquinone Methides via Site-Selective Ring Opening of 1-Siloxy-1,4-epoxy-1,4-dihydronaphthalenes

1-Siloxy-4-(benzyloxy)methyl-1,4-epoxy-1,4-dihydronaphthalenes, generated from benzynes and furans, underwent automatic site-selective ring opening because of the synergetic effect of the steric strain of the 1,4-epoxy moiety and the electron-donating ability of the siloxy group on the acetal structure to afford the precursors of ortho-naphthoquinone methides (o-NQMs). Subsequent Lewis acid-facilitated o-NQM formation and annulation with olefins afforded multi-fused heterocycles. Notably, the consecutive hexacyclic skeleton of rubioncolin B was constructed via solvent-dependent regioselective annulation of naphthofuran derivatives.This is the peer reviewed version of the following article: Aijima T., Komagawa S., Akai S., et al. Construction of Functionalized ortho-Naphthoquinone Methides via Site-Selective Ring Opening of 1-Siloxy-1,4-epoxy-1,4-dihydronaphthalenes. Advanced Synthesis and Catalysis 365, 3981 (2023), which has been published in final form at https://doi.org/10.1002/adsc.202300968. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited

Base-promoted lipase-catalyzed kinetic resolution of atropisomeric 1,1′-biaryl-2,2′-diols

Herein we report a dramatic acceleration of the lipase-catalyzed kinetic resolution of atropisomeric 1,1′-biaryl-2,2′-diols by the addition of sodium carbonate. This result likely originates from the increased nucleophilicity of the phenolic hydroxyl group toward the acyl-enzyme intermediate. Under these conditions, various substituted C2-symmetric and non-C2-symmetric binaphthols and biphenols were efficiently resolved with ∼50% conversion in only 13–30 h with excellent enantioselectivity