Catalytic asymmetric synthesis of polysubstituted cyclohexa-1,3-dienes from β-branched α,β-alkenals

3-Methyl- and 3-phenylbut-2-enal in the presence of (S)-prolinol (0.1 eq.) in benzene or THF react with the acidic monoesters of alkenylidene, and arylmethylidene-, and alkylidenemalonic acids at –10 to +22 °C to give optically active esters of 4,6-disubstituted cyclohexa-1,3-diene-l-carboxylic acids in moderate (10–43 %) yields. The enantiomeric purity of the products formed from the lint two types of acidic ylidenemalonates varies from 28 to 68 % and is higher than that observed in the case of related alkylidenemalonates. Under similar conditions cyclohexylideneacetaldehyde affords optically active derivatives of 1,5,6,7,8,8a-hexahydronaphthalene as mixtures ofcis andtrans isomers. The enantiomeric purity and absolute configuration of the cyclohexadienes thus obtained were determined using¹H NMR spectroscopy in combination with chiral solvating agents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 663–669, March, 1996.     

The effect of chiral solvent and various kinds of chiral organic salts on the asymmetric hydrogenation of methyl acetoacetate over an improved tartaric acid modified Raney nickel catalyst

The influence of the chiral ionic liquid (CIL) on the asymmetric hydrogenation of methyl acetoacetate (MAA) over an improved tartaric acid-modified Raney nickel catalyst using it as reaction medium was investigated. At the same time, we also studied the effect of up to eight chiral ionic salts, and ionic liquids on this reaction using these ionic salts as co-catalyst. Although no obviously improved optical yields were gained, the possible cause has been given.     

The role of neutral anions in ionic liquid as solvent media for the reactivity and stereoselectivity towards asymmetric Michael addition reaction of n-pentanal with β-nitrostyrene catalyzed by L-Proline

Michael addition reactions of n-pentanal with ß-nitrostyrene in achiral and chiral ionic liquids catalyzed by l-proline were studied. Results indicate anion plays an important role as weak coordination properties in the reactivity and stereoselectivity towards Michael product. 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][NTf₂]) ionic liquid was found to be the best solvent media with a high yield (up to 90%) and a high diastereomeric ratio (syn/anti: 91/9), with moderate enantioselectivity (38% ee) among ten ionic liquids tested. The ionic liquid has been reusable over five numbers of cycles.     

手性3-溴-2(5H)-呋喃酮的合成及其串联的不对称Michael加成 反应的研究

研究了新的手性试剂,5-(l-孟氧基)-3-溴-呋喃酮(5a)的合成及其与亲核性醇发生的串联不对称双Michael加成/分子内亲取代反应。通过此反应,一举生成了四个新的手性中心,得到了一般方法难以合成的含有多个手性中心的丁内酯并螺－环丙烷类化合物8a～8d。详细报道了8a～8d的合成方法以及它们的[α]、IR、UV、^1^HNMR、^13^CNMR、MS、元素分析等结构分析数据。此不对称双Michael加成/分子内亲核取代反应可以为某些新的光学活性螺－环内丙烷类化合物以及某些复杂结构的分子提供合成策略。     

Effect of the surface area of platinum on the activity of a bifunctional aluminoplatinum catalyst in the synthesis of alkylimidazoles from diamines and carbonyl acids

An investigation has been conducted into the effect of the acid and dehydrogenating functions of an aluminoplatinum catalyst on the synthesis of 2-methylimidazole from ethylenediamine and acetic acid. It has been established that formation of the intermediate 2-methylimidazoline involves the acid Al₂O₃ centers and its rate of formation is greater than the rate of its subsequent dehydrogenation to 2-methylimidazole on the Pt centers. The symbatic nature of the variations in the 2-methylimidazole yield and the surface area of the platinum in the aluminoplatinum catalyst has been demonstrated.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 1992–1996, September, 1992.     

手性噁唑硼烷催化α-和β-氨基酮不对称还原反应立体选择性的AM1过渡态模型研究

AM1 transition state (TS) models were developed for the enanfioselecfivifies in the reductions of α-and β-aminoketones catalyzed by (S)-4-benzyl-5,5-diphenyl-1,3,2-oxazaborolidine. The result showed that β-aminoketone gave better enanfioselectivity than its α-analog. Different chiralifies of the final products were obtained, R for the former and S for the latter. These semiempirical TS models are consistent with the experimental data.     

The mechanisms of the formation of by-products in the catalytic synthesis of C-alkylimidazoles from diamines and carboxylic acids

The formation of 1-ethyl-2-methylimidazole (1-Et-2-MI) and 1-ethyl-2-methylimidazoline (1-Et-2-MIN), intermediates in the synthesis of 2-methylimidazole (2-MI) from ethylenediamine (EDA) and AcOH in the presence of a platinum-on-alumina catalyst, was studied. Using CH₃ ¹⁴COOH the incorporation of two acetate units into 1-Et-2-MI and 1-Et-2-MIN molecules was demonstrated. The same products were also obtained on dehydrogenation of 2-methylimidazoline (2-MIN) under mild conditions (220–230 °C). A part of the latter is transformed to N-ethyl ethylendiamine (EEDA) and EDA. These facts indicate that both 1-Et-2-MI and 1-Et-2-MIN result from hydrogenolysis of the imidazoline ring with subsequent ethylation. A reverse reaction, the C₅-cyclization of EEDA, was also observed. The formation of 2-MI is favored by increasing temperature.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 937–940, May, 1993.     

The staged synthesis of 2-methylimidazole from ethylenediamine and acetic acid in the presence of a bifunctional aluminoplatinum catalyst

An investigation has been conducted into the staged synthesis of 2-methylimidazole from ethylenediamine and acetic acid in the presence of a bifunctional aluminoplatinum catalyst. It has been shown that the formation stage of 2-methylimidazoline occurs more quickly on -Al₂O₃ than its dehydrogenation on the Pt centers. From a comparison of the processes of dehydrogenation of 2-methylimidazoline in the molten phase and in aqueous solution it follows that the water eliminated in the imidazoline formation stage could cause the decrease in activity during the dehydrogenation on the Pt centers. The structures of the secondary and intermediate products have been established for each stage of the process and their formation routes are discussed.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 1997–2002, September, 1992.     

Melamine trisulfonic acid:A new,efficient and recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones in the absence of solvent

Melamine trisulfonic acid(MTSA) can be used as an efficient and recyclable catalyst for the promotion of the synthesis of 3,4- dihydropyrimidin-2(1H)-ones/thiones(DHPMs) in the absence of solvent.All reactions were performed at 80℃in good to high yields.     

CaO对Cu-ZnO-ZrO_2催化CO_2加H_2合成甲醇性能影响

用CaO作为改性助剂,采用并流共沉淀法制备了CuO∶ZnO∶ZrO_2为5∶4∶1(物质的量比),CaO添加量为0、1%、2%、4%、8%、16%(摩尔分数)的六组催化剂。用X射线衍射(XRD)、微商热重(TG-DTG)、傅里叶红外(FT-IR)、N2吸附脱附(BET)、X射线光电子能谱(XPS)、氢气程序升温还原(H_2-TPR)、CO_2程序升温脱附(CO_2-TPD)、NH_3程序升温脱附(NH_3-TPD)对催化剂进行了表征。用自制固定床评价了催化剂活性。结果表明,添加CaO后,催化剂路易斯酸性和表面碱性增强;催化剂母体中高温碳酸盐含量增加,热稳定性增强,CuO颗粒粒径变小,Cu-Zn协同作用增强,Cu比表面积增大,分散性变好。催化剂活性受到表面酸碱性、铜比表面积、Cu-Zn协同作用和铜分散性共同影响。当CaO为2%时,铜比表面积为79.3 m2/g、铜分散度为34.8%、CO_2转化率为24.55%、甲醇选择性为19.01%、甲醇收率为0.044 g/(gcat·h),催化剂活性最好。过量CaO占据催化剂孔道和覆盖表面活性位,使催化剂路易斯酸性和表面碱性过强,CuO与H_2有效接触减少,CO_2难以脱附,催化活性下降。因此,适量CaO(2%)添加可促进CO_2加氢反应合成甲醇。     

An improved synthesis of quinolines from β‐bromovinyl aldehydes and primary arylamines in the presence of a palladium catalyst

β‐Bromovinyl aldehydes are effectively cyclized with primary arylamines in DMF at 110 °C in the presence of a catalytic amount of a palladium catalyst to give the corresponding quinolines in high yields. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of analyte lipophilicity on the resolution of α‐ and β‐amino acids on liquid chromatographic ligand exchange chiral stationary phases

Separation of the two enantiomers of racemic α‐ and β‐amino acids on two ligand exchange chiral stationary phases (CSPs) prepared previously by covalently bonding sodium N‐((S)‐1‐hydroxymethy‐3‐methylbutyl)‐N‐undecylaminoacetate or sodium N‐((R)‐2‐hydroxy‐1‐phenylethyl)‐N‐undecylaminoacetate on silica gel was studied with variation of the organic modifier (methanol) concentration in the aqueous mobile phase. In particular, the variation of retention factors with changing organic modifier concentration in the aqueous mobile phase was found to be strongly dependent on both the analyte lipophilicity and the stationary phase lipophilicity. In general, the retention factors of relatively lipophilic analytes on relatively lipophilic CSPs tend to increase with increasing organic modifier concentration in the aqueous mobile phases while those of less lipophilic or hydrophilic analytes tend to increase. However, only highly lipophilic analytes show decreasing retention factors with increasing organic modifier concentration in the aqueous mobile phase on less lipophilic CSPs. The contrasting retention behaviors on the two CSPs were rationalized by the balance of the two competing interactions, viz. hydrophilic interaction of analytes with polar aqueous mobile phase and the lipophilic interaction of analytes with the stationary phase.     

助剂和原料气中CO2浓度对CuFeZr催化剂用于合成气制混合醇的影响

考察了不同助剂（Mn、Zn、Co）对CuFeZr催化剂用于合成气制混合醇的影响。借助BET、XRD、H₂-TPR等对其物化性质进行了表征,结果表明,加入助剂可减小颗粒粒径并且增强对CO的吸附能力以及催化剂表面碱性,其中,加入Zn可以增强CuFe间的相互作用,改善CuFeZr催化剂的还原性质,提高对CO的吸附能力,以及提供最强的表面碱性。用固定床反应器对催化剂的反应性能进行了评价,反应结果表明,加入Zn可以显著提高CuFeZr催化剂用于合成气制混合醇的反应活性及醇选择性,使醇时空收率从0.026 g/（g_cat·h）提高至0.071 g/（g_cat·h）。由于循环条件下,反应产物CO₂同时也是原料气的组成成分,进一步地探究了原料气中CO₂浓度对催化剂反应性能的影响。结果表明,加入CO₂可提高CO转化率和醇以及烃的收率,但阻碍链增长反应并使得产物烯烷比降低。其中,在所考察浓度范围内,原料气中含有2.5%的CO₂最有利于醇和烃的生成尤其是低碳醇和低碳烃的生成。     

Catalytic asymmetric synthesis and anticancer effects of the novel non-calcemic analog of vitamin D, 2α-fluoro-19-nor-22-oxa-1α,25-dihydroxyvitamin D3 in metastatic lung carcinoma

1α,25-Dihydroxyvitamin D₃ (1α,25-D₃) has potent antiproliferative and anti-invasive properties in vitro in cancer cells. However, the major limitation to its clinical use is that it causes hypercalcemia. Therefore, vitamin D analogs with potent cell regulatory effects but with weaker calcemic effects than 1α,25-D₃ are required. Among them, 22-oxa-1α,25-D₃ and 19-nor-1α,25-D₃ have anti-cancer effects with relatively low calcemic effects. Modifications at the C-2α position of the A-ring also produced analogs with a unique biological profile. Not only the side-chain but also the A-ring modification thus generates a unique analog with potent cell regulatory effects and low calcemic activity as well. We report here that the hybrid 1α,25-D₃ analog, synthesized via the highly regio- and stereo-selective ring opening 2α-fluorination and catalytic asymmetric carbonyl-ene cyclization, with 2α-fluoro, 19-nor, and 22-oxa modification exhibits unique cell regulatory activities against the development of metastatic lung carcinoma.     

Ethylp-(2-methyl-3-oxopropyl)- andp-(2-methyl-3-oxo-1-propenyl)benzoates: preparation and use in the synthesis of biologically active derivatives ofp-(nor-polyprenyl)benzoic acids

Novel ways for preparing the title compounds have been developed. Saturated (1) and unsaturated (2) aldehydoesters, which are easily accessible by a Pd-catalyzed reaction of ethyl 4-bromobenzoate with methallyl alcohol and aldol condensation of ethyl 4-formyl-benzoate with propanal, respectively, are strategically advantageous intermediates for the synthesis. The results of thein vitro assays of some of the synthesized compounds are compared with the known data on their pharmacological effectsin vivo.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2126–2129, December, 1993.