已经制备了一对异构乙酰辅酶 A(乙酰辅酶 A)类似物,其中硫酯基团被仲醇取代。这两种异构体在仲醇的立体构型方面不同,旨在模拟乙酰辅酶 A 依赖性乙酰转移酶反应中四面体中间体或过渡态的两种可能构型。测试这两种异构体作为氯霉素乙酰转移酶和肉碱乙酰转移酶的抑制剂,这两种酶先前已被预测形成与 (S)-醇的构型匹配的四面体中间体。(S)-异构体是两种酶的更有效抑制剂,其 Ki 值比 (R)-异构体的 Ki 值低 12 倍和 6 倍。(S)-异构体也是更有效的磷酸乙酰转移酶抑制剂,乙酰辅酶A合成酶和芳胺乙酰转移酶,其四面体中间体的立体化学以前未知。这些结果表明...
The Michaelreaction of various nitroalkanes 1 with electrophilic alkenes 2 can be performed in NaOH (0.025−0.1 M), without any organic solvent. In many cases the presence of cetyltrimethylammonium chloride (CTACl), as cationic surfactant, produces better results. Good yields of the products 3 are obtained even with hindered, and functionalized starting materials.
A New, One Pot Synthesis of Alkylated Methyl Tri- and Tetracarboxylate Derivatives by Nitrolkanes
作者:Roberto Ballini、Giovanna Bosica、Dennis Fiorini、Maria Victoria Gil、Alessandro Palmieri
DOI:10.1055/s-2004-815948
日期:——
The reaction of nitroalkanes with trimethyl trans-aconitate in acetonitrile, in the presence of DBU as base, allows the one pot formation of alkylated methyl tri- and tetralkanoate derivatives via base induced nitrous acid elimination. The title compounds can also be obtained, in one flask, starting with the reaction of methyl nitroacetate with dimethyl maleate, followed by the addition, in the same flask of the nitroalkane.
Baker's yeast reduction of prochiral γ-nitroketones: Enantioselective synthesis of (S)-4-nitroalcohols
作者:Antonio Guarna、Ernesto G. Occhiato、Laura M. Spinetti、Maria E. Vallecchi、Dina Scarpi
DOI:10.1016/0040-4020(94)01056-6
日期:1995.2
The baker'syeastreduction of seven different prochiral nitroketones 1a-g occurred on the re face of the carbonyl group, thus affording the (S)-nitroalcohols 2a-g, with different level of enantioselectivity (e.e. 15–99%). The best results (e.e. = 99%) were achieved when the substituent R is markedly different from the nitroalkyl group [e.g. 1a (R = Me) and 1e (R = o-MeO-C6H4)]. The e.e. and the configuration
Baker的七个不同的前手性硝基酮酵母还原1A-G上发生了重新羰基的面,由此提供第(小号)-nitroalcohols 2A-G ,具有不同水平的对映选择性(EE 15-99%)。当取代基R与硝基烷基显着不同时(例如1a(R = Me)和1e(R = o -MeO-C 6 H 4)),可获得最佳结果(ee = 99%)。通过相应的Mosher酯的NMR研究确定了生物产物的ee和构型,在一种情况下(2d)的化学相关性。还描述了从2d开始的光学活性内酯7和吡咯烷11的合成。
A New Two-Step Synthesis of 2-Alkylated 1,4-Diketones and α-Alkylated γ-Keto Esters
作者:Roberto Ballini
DOI:10.1055/s-1999-3533
日期:1999.7
A Two Steps Synthesis of γ-Substituted and γ,γ-Disubstituted α-(Alkylmethylene)-γ-butyrolactones