アシルシランエノラートのアルドール反応による連続不斉中心の選択的生成

金沢大学工学部アシルシランシリルエノールエーテル(1)とキラルアルデヒドジメチルアセタール(2)の反応による三連続不斉中心を有するアルドール付加体の生成と、その求核試薬との反応による四連続不斉中心の立体選択的構築について検討した。これらのアルドール反応では、3連続不斉中心を有する4種類の異性体のうち、3、4位炭素の立体配置がsynに規制され、2、3位炭素のそれが異なる2,3-syn-3-メトキシ-1-シリル-1-ブタノン誘導体(3)または2,3-anti-3のいずれかが優先的に生じた。すなわち、ベンジルアシルシランから生成したE-またはZ-1Aとフェニルプロパナ-ルジメチルアセタール(2A)との塩素チタン触媒反応では、E-1Aから2,3-syn-体(3S)が、Z-1Aからは2,3-anti-異性体(3a)がそれぞれ高ジアステレオ選択的に生成した。一方、シリルトリフラート触媒反応では、E、Zいずれの1Aからも3aが優先的に生じた。また、その他のアルキルアシルシランエノールエーテル(1B)と2Aや2-メチルブタナ-ルジメチルアセタール(2B)との反応では、用いた1Bの立体化学と触媒に無関係に、2,3-syn-体(3s)の生成が優先した。本反応における2、3位炭素の立体規制は鎖状遷移状態モデルに、3、4位炭素のそれはCramモデルによって説明された。3にアルキルリチウムを反応させ、対応する4連続不斉中心をもつ3-メトキシ-1-シリル-1-ブタナ-ル誘導体(4)を定量的、かつ高ジアステレオ選択的に得た。4のフッ素アニオン試薬による脱シリルプロトン化は、定量的、かつ立体特異的に進み対応する1,2-anti-3-メトキシ-1-ブタナ-ル誘導体を生じた。3と求核剤での高立体選択性の発現は、3のカルボニル酸素とメトキシ酸素に金属イオンが配位した環状構造を経由して反応が進行したためと考えている。研究課題/領域番号:05750766, 研究期間(年度):1993出典：研究課題「アシルシランエノラートのアルドール反応による連続不斉中心の選択的生成」課題番号05750766（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-05750766/）を加工して作

アシルシランの特性を利用した分子変換反応に関する研究

取得学位：博士(工学)，学位授与番号：博乙第299号，学位授与年月日：平成18年3月22日,学位授与年：200

New route for synthesis of 3- and 5-caffeoylquinic acids via protected quinic acids

Caffeoylquinic acids (CQAs) are a group of the phenylpropanoids produced by certain plant species, which have various biological activities including antioxidant, antibacterial, anticancer, and others. Several synthetic routes have been developed using quinic acids (QAs) and caffeic acid derivatives as starting materials. In this study, alternative pathways of 3- and 5-CQAs preparation using protected quinic acids are described. Both CQAs were achieved by removal of the protecting groups of compound 9 and 18 with acid hydrolysis using dilute HCl solution. These compounds (9 and 18) are novel, resulted from esterification reaction of diacetyl caffeoyl chloride and protected quinic acids. The hydroxyl groups of quinic acid in this case were protected with 2,2-dimethoxy propane or tert-butyldimethylsilyl (TBS) chloride

Joint Symptoms, Aromatase Inhibitor-Related Adverse Reactions, Are Indirectly Associated with Decreased Serum Estradiol

Background. Joint symptoms (JSs) are problematic adverse drug reactions (ADRs) of aromatase inhibitors (AIs). Involvement of decreased serum estradiol (SE) has been suggested. Patients and Methods. 104 postmenopausal breast cancer patients administered an AI were prospectively investigated regarding various clinical parameters, JS and hot flashes as ADRs, and the SE level. Results. JS manifested in 31.7% of patients and hot flashes in 18.3%. Chi-square testing showed a significantly higher incidence of JS in several patient strata: <55 years old, decreased SE, and elevated total cholesterol (TC). In univariate analysis, JS correlated significantly with a pre-AI % YAM of ≥80%, decreased SE, and elevated TC. Eight (7.7%) patients maintained SE at ≥5 pg/mL for >6 consecutive months, with no JS. In chi-square testing, hot flashes showed a significantly higher incidence in patients <55 years old. Conclusion. AI-ADRs occurred more readily in younger patients. Decreased SE may be indirectly involved in JS

Stereoselective hetero Diels-Alder reaction of selenoaldehydes with pentavalent phosphole chalcogenides

金沢大学大学院自然科学研究科物質創成金沢大学工学部Stereoselective hetero Diels-Alder reaction of selenoaldehydes, generated by thermal retro Diels-Alder reaction of anthracene cycloadducts, with pentavalent 3,4-dimethylphosphole chalcogenides at 110 °C in toluene to give the corresponding [4+2] cycloadducts as a single diastereoisomer in good yields, accompanied by a slight scrambling of chalcogen atoms. Higher reaction temperature led to an increase of the scrambling between chalcogen atoms. © 2007 Elsevier Ltd. All rights reserved

Genetic screen in Drosophila muscle identifies autophagy-mediated T-tubule remodeling and a Rab2 role in autophagy.

Transverse (T)-tubules make-up a specialized network of tubulated muscle cell membranes involved in excitation-contraction coupling for power of contraction. Little is known about how T-tubules maintain highly organized structures and contacts throughout the contractile system despite the ongoing muscle remodeling that occurs with muscle atrophy, damage and aging. We uncovered an essential role for autophagy in T-tubule remodeling with genetic screens of a developmentally regulated remodeling program in Drosophila abdominal muscles. Here, we show that autophagy is both upregulated with and required for progression through T-tubule disassembly stages. Along with known mediators of autophagosome-lysosome fusion, our screens uncovered an unexpected shared role for Rab2 with a broadly conserved function in autophagic clearance. Rab2 localizes to autophagosomes and binds to HOPS complex members, suggesting a direct role in autophagosome tethering/fusion. Together, the high membrane flux with muscle remodeling permits unprecedented analysis both of T-tubule dynamics and fundamental trafficking mechanisms

Crystal structures of racemic and enantiomeric 5-isopropyl-5-methylhydantoin

Crystal structures of racemic and enantiomeric 5-isopropyl-5-methylhydantoin (IPrMH) have been determined by single crystal X-ray diffraction. Melting temperatures and solid state infrared spectra are also measured. Racemic IPrMH has a lower melting temperature than the pure enantiomer by 25 °C. The infrared spectrum of racemic IPrMH is identical with that of the pure enantiomer. Nevertheless, the racemic IPrMH doesn’t crystallize as a conglomerate but as a racemic compound. The racemic and the enantiomeric crystals are very similar to each other in molecular geometries and intermolecular interactions. In the both cases, the molecules are connected via N−H···O hydrogen bonds to form R22(8) rings, and these rings are linked into infinite one-dimensional tapes. In the racemic crystal, a single tape is composed of single enantiomer and itself is homochiral

A case of matrix-producing carcinoma of the breast

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An efficient 1,3-dipolar cycloaddition between aromatic selenoaldehydes and nitrile oxides or nitrile imines: an easy access to selenium-containing five-membered heterocyclic ring system

金沢大学大学院自然科学研究科物質創成金沢大学工学部1,3-Dipolar cycloaddition between aromatic selenoaldehydes, generated by thermal retro Diels-Alder reaction of anthracene cycloadducts, and nitrile oxides or nitrile imines proceeded efficiently to give the corresponding [3+2] cycloadducts as a single isomer in good yields, being 1,4,2-oxaselenazoles or 1,3,4-selenadiazoles, respectively. © 2007 Elsevier Ltd. All rights reserved