丝氨酸蛋白酶肠肽酶(EP)的抑制为发现用于治疗代谢性疾病的化学疗法开辟了一条新途径。在日本,卡莫司他已被临床用于治疗慢性胰腺炎。但是,尚未完全阐明观察到的临床疗效的机理基础。我们证明了camostat是EP的有效可逆共价抑制剂,其抑制力(k inact / K I)为1.5×10 4 M -1 s -1。高分辨率液相色谱-质谱(LC-MS)显示,在与卡莫司他反应后,EP中添加了161.6 Da,这与卡莫司他的羧基苯基胍部分的插入相符。camostat对EP的共价抑制是可逆的,酶的半衰期为14.3小时。共价加合物的形成进一步受到解析为2.19Å的晶体结构的支持,这表明密莫司他的紧密类似物对EP的催化丝氨酸进行了修饰,导致形成了羧基苯胍基酰基转移酶,与预期的相同。特别要注意的是,稳压器的微小结构修饰导致了抑制机制的改变。我们从其他研究中观察到,需要持续抑制EP才能减少累积食物摄入量和体重,同时
Copper-catalyzed coupling of aryl iodides and tert-butyl β-keto esters: efficient access to α-aryl ketones and α-arylacetic acid tert-butyl esters
作者:Duo Zhao、Yongwen Jiang、Dawei Ma
DOI:10.1016/j.tet.2013.10.017
日期:2014.5
catalyzed coupling of aryl iodides with tert-butyl β-ketoesters proceeded smoothly at 40 °C in DMF, providing α-aryl ketones after acid-promoted deprotection and decarboxylation of tert-butyl ester group. While CuI/2-picolinic acid catalyzed coupling of aryl iodides with tert-butyl acetoacetate at 70 °C in dioxane delivered α-arylacetic acid tert-butyl esters upon spontaneous deacylation. A wide range of
CuI /反-4-羟基-1-脯氨酸催化的芳基碘化物与叔丁基β-酮酯的偶联在DMF中在40°C下顺利进行,在酸促进叔丁酯的脱保护和脱羧反应后得到α-芳基酮团体。CuI / 2-吡啶甲酸在二恶烷中于70°C催化芳基碘化物与乙酰乙酸叔丁酯偶合时,在自发脱酰作用下释放出α-芳酸叔丁酯。各种各样的官能团,例如乙酰基,甲氧基,腈,硝基,溴和氯与反应条件相容。
Palladium-Catalyzed α-Arylation of Esters with Chloroarenes
作者:Takuo Hama、John F. Hartwig
DOI:10.1021/ol800258u
日期:2008.4.1
Palladium-catalyzed alpha-arylations of esters with chloroarenes are reported. The reactions of chloroarenes with the sodium enolates of tert-butyl propionate and methyl isobutyrate occur in high yields with 0.2-1 mol % of [P(t-Bu)3]PdBr}2 or the combination of Pd(dba)2 and P(t-Bu)3 as catalyst. The reactions of chloroarenes with the Reformatsky reagent of tert-butylacetate were most challenging but occurred
Catalytic Asymmetric Fluorination of Copper Carbene Complexes: Preparative Advances and a Mechanistic Rationale
作者:Michael Buchsteiner、Luis Martinez‐Rodriguez、Paul Jerabek、Iago Pozo、Michael Patzer、Nils Nöthling、Christian W. Lehmann、Alois Fürstner
DOI:10.1002/chem.202000081
日期:2020.2.21
Cu-catalyzed reaction of substituted α-diazoesters with fluoride gives α-fluoroesters with ee values of up to 95 %, provided that chiralindane-derivedbis(oxazoline) ligands are used that carry bulky benzyl substituents at the bridge and moderately bulky isopropyl groups on their core. The apparently homogeneous solution of CsF in C6 F6 /hexafluoroisopropanol (HFIP) is the best reaction medium, but
取代的 α-重氮酯与氟化物的铜催化反应可产生 ee 值高达 95% 的 α-氟酯,前提是使用手性茚满衍生的双(恶唑啉)配体,该配体在桥上带有大的苄基取代基和中等大的异丙基以团体为核心。CsF 在 C6 F6 /六氟异丙醇 (HFIP) 中的明显均匀溶液是最好的反应介质,但在两相混合物 CH2 Cl2 /HFIP 中的 CsF 也能提供良好的结果。DFT 研究表明,氟化物首先攻击瞬时供体/受体卡宾中间体的 Cu 原子,而不是 C 原子。这个不寻常的步骤之后是 1,2-氟化物位移;为了发生这种迁移插入,卡宾必须绕 Cu-C 键旋转以确保轨道重叠。C2 对称结合位点内的这种旋转运动的方向性决定了感应的感觉。该模型与使用通过毛细管结晶生长的这种先验蜡状材料的单晶通过 X 射线衍射测定的所得产物的绝对构型非常一致。
Palladium-Catalyzed α-Arylation of Zinc Enolates of Esters: Reaction Conditions and Substrate Scope
作者:Takuo Hama、Shaozhong Ge、John F. Hartwig
DOI:10.1021/jo401476f
日期:2013.9.6
The intermolecular α-arylation of esters by palladium-catalyzed coupling of aryl bromides with zinc enolates of esters is reported. Reactions of three different types of zinc enolates have been developed. α-Arylation of esters occurs in high yields with isolated Reformatsky reagents, with Reformatsky reagents generated from α-bromo esters and activated zinc, and with zinc enolates generated by quenching
报道了通过芳基溴化物与酯的烯醇锌的钯催化偶联实现酯的分子间α-芳基化。已经开发出三种不同类型的烯醇锌的反应。使用分离的 Reformatsky 试剂、使用由 α-溴代酯和活化锌生成的 Reformatsky 试剂以及使用氯化锌猝灭酯的碱金属烯醇化物生成的锌烯醇化物,可以高产率进行酯的 α-芳基化。使用烯醇锌代替碱金属烯醇化物大大扩展了酯的芳基化范围。该反应在室温或 70 °C 下与含有氰基、硝基、酯、酮、氟、烯醇化氢、羟基或氨基官能团的溴代芳烃以及与溴代吡啶发生。酯的范围包括无环乙酸酯、丙酸酯和异丁酸酯、α-烷氧基酯和内酯。使用带有受阻五苯基二茂铁基二叔丁基膦(Q-phos)或高反应性二聚Pd(I)络合物[P( t -Bu) 3 ]PdBr} 2 的催化剂进行酯的烯醇锌的芳基化。
Photoinduced Palladium‐Catalyzed Negishi Cross‐Couplings Enabled by the Visible‐Light Absorption of Palladium–Zinc Complexes
作者:Irini Abdiaj、Lena Huck、José Miguel Mateo、Antonio de la Hoz、M. Victoria Gomez、Angel Díaz‐Ortiz、Jesús Alcázar
DOI:10.1002/anie.201808654
日期:2018.10
A visible‐light‐induced Negishicross‐coupling is enabled by the activation of a Pd0–Zn complex. With this photocatalytic method, the scope of deactivated aryl halides that can be employed in the Negishicoupling was significantly expanded. NMR experiments conducted in the presence and absence of light confirmed that the formation of the palladium–zinccomplex is key for accelerating the oxidative