Thermodynamic equilibration of dihydropyridone enolates: application to the total synthesis of (+/−)-epiuleine

Following 1,4-reduction of 2-substituted dihydropyridones (1), the requisite ‘kinetic’ enolate can be isomerized upon warming to allow the isolation of the thermodynamic enolate as its vinyl triflate (3). This enolate interconversion is dependent on the dihydropyridone C-2 substituent and can be interpreted in terms of conformational analysis. This novel scaffold (3) opens another avenue for the strategic deployment of dihydropyridones into both natural product synthesis and drug discovery. To this end, this method is highlighted by its use as a key step in a total synthesis of (+/−) epiuleine (14).     

利用微波技术合成4-芳基-5-甲氧羰基-6-甲基3,4-二氢吡啶-2-酮

微波辐射;二氢吡啶酮;芳醛;麦氏酸;利用微波技术合成4-芳基-5-甲氧羰基-6-甲基3;4-二氢吡啶-2-酮     

Carbonyl-containing spiro-dihydrofurans in reactions with ammonium acetate and hydrazine hydrate

It has been shown that 2-spiro(3-R-6,6-dimethyl-4-oxo-2,3,4,5,6,7-hexahydrobenzofuran)-2′-(5′, 5′-dimethylcyclohexane-1′,3′-diones) undergo conversions in reactions with ammonium acetate and hydrazine hydrate into substituted dihydropyridin-2-ones and tetrahydro-1,2-diazepin-7-ones respectively as a result of ring-opening of the spirodimedonyl fragment through the corresponding amides and hydrazides of δ-keto acids. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1800–1804. December, 2005.     

微波辐射下4-苯基-5-乙氧羰基-6-甲基-3,4-二氢吡啶-2-酮的合成和晶体结构

标题化合物C1 5H1 6NO3由苯甲醛、醋酸铵、乙酰乙酸乙酯、麦氏酸在微波辐射下干反应而得。结构通过单晶X 射线衍射法测定 ,其晶体属单斜晶系 ,空间群P1 ,a =7.870 (1 ) ,b =9 2 90 (1 ) ,c=1 0 .640 (2 ) ,α =1 0 2 .76(3) ,β =1 1 0 .42 (3) ,γ =96.92 (3)°,V =694.2 (2 ) 3,Z =2 ,Mr=2 59.30 ,Dc=1 .2 4 0 g/cm3,μ(MoKα) =0 .0 86mm- 1 ,F(0 0 0 )=2 76。晶体结构用直接法解出 ,经用全矩阵最小二乘法对原子参数进行修正 ,最终的偏离因子为R =0 0 4 2 3,wR =0 .1 2 57。在晶体结构中 ,吡啶酮环与苯环之间的二面角为 87.31°。     

Novel asymmetric total synthesis of the natural (+)-6-epicastanospermine

An efficient noncarbohydrate-based enantioselective synthesis of (+)-6-epicastanospermine has been developed utilizing the Sharpless asymmetric aminohydroxylation of furyl acrylate and oxidation of α-furfurylamine derivative 17 as key steps.     

功能化离子液体为载体液相合成二氢吡啶酮衍生物

在微波辐照条件下, 以甲基咪唑、氯乙醇和四氟硼酸钠为原料制备了含羟基功能化离子液体1-(2-羟乙基)-3-甲基咪唑四氟硼酸盐([2-hydemim][BF₄]), 并以其为液态载体, 首先与乙酰乙酸乙酯反应, 得到的中间体再分别和Meldrum酸、醋酸铵以及各种芳香醛反应, 最后在温和的条件下用甲醇钠进行切割反应, 得到了一系列产率和纯度较高的3,4-二氢吡啶酮衍生物, 目标化合物不需要进一步的色谱纯化处理, 纯度为95%～98%, 产率为83%～93%. 回收得到的功能化离子液体可以重复套用至少6次也不影响其活性. 表明该方法是一种高效的3,4-二氢吡啶酮衍生物的组合化学合成方法.