巻号一覧
63 巻, 7 号
選択された号の論文の7件中1～7を表示しています
- |<
- <
- 1
- >
- >|
-
丸岡 啓二2005 年 63 巻 7 号 p. 686-695
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーApart from enzymes as biocatalysts, a broad repertoire of chiral reagents, auxiliaries, and catalysts can be developed in recent years. In this respect, the design of new catalysts and new reactions in a practical and an environmentally benign manner is increasingly important in the 21st century for the construction of new and useful organic molecules. Accordingly, we have developed new catalytic asymmetric reactions based on [1] the rational design of conceptually new, chiral bidentate Lewis acids (particularly, aluminum and titanium Lewis acids) in organic synthesis including catalytic asymmetric synthesis; [2] the design of environmentally benign, binaphthylmodified chiral phase-transfer catalysts as chiral organocatalysts for practical asymmetric synthesis.抄録全体を表示PDF形式でダウンロード (1590K) -
田中 克典, 勝村 成雄2005 年 63 巻 7 号 p. 696-708
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーRecently, we found that (E)-3-carbonyltrienal compounds irreversibly reacted with the specific Lys of phospholipase A2 (PLA2) to produce 1, 2-dihydropyridine via facile 6π-azaelectrocyclization leading to inactivation of the enzyme. The smooth azaelectrocyclization was due to the presence of both the C 4-carbonyl group and the C 6-alkenyl group in 1-azatriene: this attractive discovery prompted us to investigate the substituent effects on azaelectrocyclization and to develop it as a method of natural products synthesis. The paper describes our efforts on (i) establishing the new synthesis of 3-cis-1-azatrienes as the precursors of azaelectrocyclization, (ii) cyclization studies, and (iii) rationale for smooth electrocyclization based on molecular orbital calculation. Then, we achieved (iv) one-pot pyridine synthesis and (v) highly stereoselective asymmetric azaelectrocyclization, which were applied to the formal syntheses of the ocular age pigment, A 2-E, and an optically active indole alkaloid, 20-epiuleine, respectively.抄録全体を表示PDF形式でダウンロード (2093K) -
アルドラーゼ抗体から低分子のアミノ酸およびアミン触媒まで田中 富士枝, Carlos F. Barbas III2005 年 63 巻 7 号 p. 709-721
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーEnamines are key intermediates in both organic chemistry and enzyme catalysis. Natural aldolase enzymes form an enamine intermediate from aldehydes and ketones in order to catalyze aldol reactions under mild ambient conditions. We have developed man-made aldolase catalytic antibodies and small peptides that catalyze aldol reactions, in which catalyst molecules form enamines from aldehydes and ketones in situ, like natural aldolase enzymes do. Through these studies, we have also developed small amine- and amino acid-catalyzed bond-forming reactions that use an enamine mechanism and that can be performed under mild ambient conditions. These low molecular weight amines form enamine intermediates in situ and the enamine reacts with electrophiles to afford products with high diastereo- and enantioselectivities. Our organocatalytic methodologies include catalytic asymmetric aldol, Mannich, Michael, and Diels-Alder reactions. Our catalysts, from aldolase antibodies to small organic amine and amino acid catalyst molecules, emulate many of the features of nature's enzymes.抄録全体を表示PDF形式でダウンロード (2048K) -
カルボシランデンドリマー構造がO157 : H7が産生するベロ毒素の阻害活性に及ぼす効果照沼 大陽, 松岡 浩司, 幡野 健2005 年 63 巻 7 号 p. 722-727
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーAs a novel type of artificial multivalent receptor for verotoxins, eight pairs of carbosilane dendrimers carrying up to 36 units of trisaccharide moieties of globotriaosyl ceramide (Galα1-4 Galβ1-4 Glcβ1-Cer) were prepared. The receptors (referred to as SUPER TWIG) were obtained in a generally applicable one-pot reaction by treating periphery functionalized carbosilane dendrimers with globotriaose derivative which has a thiobenzyl ether moiety as a precursor for generation of thiolate anion under Birch reduction conditions. Biological estimations of SUPER TWIGs for inhibition of Shiga toxin-producing Escherichia coli O157 : H7 showed unexpected magnitude depend on the structure of the carbosilane dendrimer used both in vitro and in vivo. It was found that the carbosilane dendrimer carrying six periphery units of trisaccharide moieties (referred to as Dumbbell (1)6) is one of the most effective agent among the SUPER TWIGs we prepared so far.抄録全体を表示PDF形式でダウンロード (1139K) -
久保寺 登2005 年 63 巻 7 号 p. 728-738
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーA little over two decades ago, the vitamin D3 activation pathway was elucidated and alfacalcidol arrived on the scene as a prodrug for active vitamin D3, 1α, 25-dihydroxyvitamin D3, to remedy vitamin D3 deficiency. With the concurrent reported discovery of the differentiation-inducing effect of active vitamin D3, its diverse physiological effects have become appreciated and the research aiming to accentuate selected physiological effects by analogue synthesis has made a fresh development. Our studies aimed particularly at separating the differentiation-inducing effect/cell growth-inhibitory effect and the calcemic effect of active vitamin D3 led to the development of two characteristic analogues, OCT and ED-71. OCT, characterized by its profound differentiation-inducing effect and modest calcemic effect, is currently in practical use as an injectable therapeutic agent for secondary hyperparathyroidism as well as in clinical settings an ointment for the treatment of psoriasis vulgaris, an intractable skin disease. The other analogue, ED-71, possesses a profile inverse to that of OCT and is now under clinical development as an oral preparation for treatment of osteoporosis. The present overview focuses on the search for and synthesis of OCT and ED-71. It also refers to methodology of searching next-generation analogues, exemplifying a new analogue, DD-281, based on the knowledge accumulated through process development of OCT and ED-71.抄録全体を表示PDF形式でダウンロード (1648K) -
井上 豪, 甲斐 泰, 裏出 良博2005 年 63 巻 7 号 p. 739-745
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーHematopoietic prostaglandin (PG) D synthase (H-PGDS) catalyzes the isomerization of PGH2 to PGD2, an allergic and inflammatory mediator, in the presence of glutathione (GSH) in mast and Th2 cells. We have determined the crystal structures of the Ca2+- and Mg2+- bound forms of human H-PGDS, revealing the metal activation mechanism, in which Ca2+ or Mg2+ increases its activity to150% of the basal level, with half maximum effective concentrations of 400μM for Ca2+ and 50μM for Mg2+. Especially, we found a four-fold reduction in the Km of the enzyme for GSH in the presence of Mg2+. We also performed the X-ray crystallographic studies of the complex crystals with some inhibitors. Among them HQL-79 is effect with orally treatment with IC50 value of 5.8μM, and three new inhibitors derived from HQL-79 were designed. The complex structures with these inhibitors provide a novel insight into the anti-allergic drug designs.抄録全体を表示PDF形式でダウンロード (1892K) -
田中 富士枝, 久保寺 登, 照沼 大陽, 井上 豪2005 年 63 巻 7 号 p. 746
発行日: 2005/07/01
公開日: 2009/11/13
ジャーナル フリーPDF形式でダウンロード (209K)
- |<
- <
- 1
- >
- >|