Amide Ionic Liquids(AILs)/L-Proline Synergistic Catalyzed Asymmetric Mannich Reactions

Amide ionic liquids （MLs）/L-proline synergistic catalyzed Mannich reactions of isovaleraldehyde, methyl ketones, and aromatic amines were carried out in moderate to high yields （ up to 96% ） and high stereo selectivities （ 〉99% e. e. ）. The products were easily isolated by extraction; and the catalyst system was readily recycled at least thrice without significant loss of efficiency. The scope of the substrates was studied and the interpretation of the manifest improvement of the reaction rates and enantio-selectivity of the novel catalyst system was speculated.

A New Investigation of Mannich Reaction

During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of product IM is postulated and discussed on the basis of deuterium labelling.

Theoretical Studies on the Mechanism of Mannich Reaction Involving Iminium Salt as Potential Mannich Reagent(1)--Use Acetaldehyde as Pseudo-acid Component

This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calculations, the activation energies of key steps in conventional Mannich reactions between ammonia, formaldehyde and acetaldehyde in neutral and acidic media are 438 8 kJ/mol and 393 9 kJ/mol respectively. The activation energy of the rate controlling step of the Mannich reaction which contains the potential Mannich reagent is 274 7 kJ/mol. Therefore, it can be derived that the potential Mannich reagent can increase the rate of the reaction remarkably. The reasons for this have been discussed in terms of the orbital match and electrostatic interaction between the atoms of reactant complexes. In this paper another different conjectured mechanism of the potential Mannich reagent which can reduce the activation energy is considerably studied.

Synthesis and Crystal Structure of the Derivative of Hydroquinone from Mannich Reaction

The regioselective Mannich-type aminomethylation of hydroquinone afforded a nitrogen-containing compound, 2,5-bis-(morpholinomethyl)hydroquinone A, and its crystal structure was determined by single-crystal X-ray diffraction. Crystal data for A: C16H24N2O4, Mr = 308.37, orthorhombic, space group Pbca, a = 10.479(4), b = 10.298(4), c = 14.865(5) ?, V = 1604.3(11) ?3, Z = 4, Dc = 1.277 g/cm3, F(000) = 664, μ = 0.092 mm-1, GOF = 1.078, the final R = 0.0508 and wR = 0.1075 for 1416 observed reflections with I > 2σ(I). There exist two intramolecular O–H…N hy- drogen bonds between the phenolic O atoms and the morpholine N donors and the morpholino rings assume the preferred chair conformation.

Stereoselectivities in α- and β-Amino Acids Catalyzed Mannich Reactions Involving Cyclohexanone

The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C ＂C bond-forming step with the addition of enamine intermediate to the imine for the L-proline（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-amino acid）-catalyzed processes were reported.B3LYP/6-31G calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts（syn-selectivity for the ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.

Effect of Polyethyleneimine Assisting the Growth of Eu-doped ZnO Nanowire Arrays in Mannich Reaction

In study on the growth reaction mechanism of Eu-doped ZnO nanowire（NW）, the intermedium of reaction is characterized by measures such as FTIR. Besides, the influences of polyethyleneimine（PEI） on morphology, structure and photoelectric property of NW are observed by SEM, TEM, XRD, UV-vis and PL spectrum. According to the result, it manifests that Eu-doped ZnO NW array growth response experiences six mutually associated reaction processes in PEI-HMTA system：（a） chelation reaction of PEI and Zn^2＋ ＆ Eu^3＋;（b） protonation reaction of PEI and NH_3;（c） decomposition reaction of hexamethylenetetramine（HMTA）;（d） Mannich reaction of HCHO and PEI;（e） formation of precursor of Eu-doped ZnO;（f） dehydration condensation of Eu-doped ZnO precursors, further forming a doped ZnO NW array. Among them, PEI is the key factor of the whole doping growth reaction process. It both plays a role in modifying the growth of ZnO NW and makes it become longer and thinner. In the meantime, it also facilitates doping of Eu and enables ZnO NW to capture more photoelectrons and higher transmission rate, which is critical to improve photovoltaic performance of optoelectronic devices.

A New One-Pot Synthesis of Macroheterocycles Using Mannich Reaction

Three N,N-heterylmethyl derivates of diaza-18-crown-6(I) are readily prepared by the reaction of (I) with paraformaldehyde and heterocyclic compounds in dry benzene.

苯磺酸锰配合物的制备及其催化Mannich反应性能研究

以氯化锰与苯磺酸钠为原料,通过加热合成了苯磺酸锰,进一步将溶剂挥发,得到了苯磺酸锰配合物.通过单晶X-射线衍射技术测定了晶体结构,分子式为:[Mn(H_(2)O)_(6)](C_(6)H_(5)SO_(3))2.粉末X-射线衍射证明目标产物具有较高的相纯度.红外光谱法验证了目标产物的分子结构.热重分析方法表明目标产物的热稳定性较好,在510℃前未分解.实验使用Mannich反应作为探针,考察了苯磺酸锰配合物的催化性能,结果表明,该配合物在催化Mannich反应时,用量少,效率高,重复使用三次仍保持催化活性,苯磺酸锰配合物催化性能良好.

酒石酸衍生的双羟基手性磷酸催化不对称Mannich-type反应

设计合成了数种由天然酒石酸衍生的双羟基手性磷酸,并考察了其对不对称Mannich-type反应的催化性能.结果发现:设计合成的双羟基手性磷酸可以高效催化该反应,并显示中等至良好的对映选择性(高达91%ee).

Sulfonated poly(4-vinylpyridine) heteropolyacid salts:A reusable green solid catalyst for Mannich reaction

Sulfonated poly（4-vinylpyridine） heteropolyacid salts acted as a heterogeneous catalyst to effectively catalyze the one-pot synthesis of β-amino carbonyl compounds via the Mannich reaction between aromatic aldehydes, aromatic ketone, and aromatic amines. In addition, the catalyst could be easily recovered by the filtration and reused six times without significant loss of catalytic activity.

PEG-OSO_3H as an efficient and recyclable catalyst for the synthesis of β-amino carbonyl compounds via the Mannich reaction in PEG-H_2O

Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H_2O（1：1） as environment-friendly solvents.The reactions were completed in short times and mild reaction conditions with good to excellent yields.

One-pot Three-component Mannich Reaction Catalyzed by 2-Hydroxylpyridine

An effcient synthetic protocol for the β-amino carbonyl compounds was developed via one-pot three- component Mannich reaction of aromatic aldehydes, aromatic amines and cyclohexanone catalyzed by 2-hydroxylpy- ridine under mild reaction conditions, β-Amino carbonyl compounds were obtained in moderate to good yields and rea- sonable diastereoselectivities. The effects of different solvents, catalyst amounts and the scope of different substrates on the Mannich reactions were investigated. The plausible reaction mechanism was also discussed.

Scope and Limitations of Optical Pure Hydantoins as Chiral Auxiliaries in Asymmetric Mannich Reactions

The Mannich reaction of various 5-substituted and N-acyl substituted chiral hydantoins with a series of aldimines smoothly occurred with full stereochemical control. These Mannich adducts have been cleaved by alcoholysis to afford several synthetically useful chiral building blocks like β-amino esters and β-lactams in good yields and in enantiopure form.

Synthesis,Characterization and Application of Some Axially Chiral Binaphthyl Phosphoric Acids in Asymmetric Mannich Reaction

Two novel chiral Brønsted acids 3b and 3c were prepared without involving the complexity of Suzuki coupling.Catalyst 3c bearing two additional hydroxyl groups at 3 and 3'positions of axially chiral 1,1-binaphthalene-2,2'-diol phosphoric acid was applied in a model Mannich reaction to affordβ-amino ester in high yield(92%)and enantiomeric excess(91%)at low reacting temperature of−40℃.In addition,thoseβ-amino ester derivatives with high yields and excellent enatioselectivities were obtained in the presence of catalyst 3c under the above condition.

Chiral Phase-transfer Catalysts Bearing Multiple Hydrogen-bonding Donors Derived from Amino Acids： Efficient Catalysts for Diastereo- and Enantioselective Nitro-Mannich Reaction

The asymmetric nitro-Mannich reaction is one of the traditional methods for forming carbon-carbon bond. By this reaction, the corresponding products with two contiguous stereocenters containing nitrogen substituents can be obtained. These β-nitro amine products can be easily transformed into 1,2-diamines by reduction of the corresponding nitro groups by means of the Nef reaction. It is well known that chiral 1,2-diamines Nay an important role in many fields.

Isosteviol-amino Acid Conjugates as Highly Efficient Organocatalysts for the Asymmetric One-pot Three-component Mannich Reactions

Isosteviol 氨基的酸结合被综合并且是与 hydroxyacetone 为不对称的三部件的 Mannich 反应用作 chiral 催化剂施主分子。好收益(多达 98%) 和优秀 stereoselectivities (依赖 97:3 医生和 99% ee ) 在一短反应时间被完成。另外， -hydroxy--amino 羰基混合物的 syn 配置或反配置与不同 chiral 催化剂作为主要产品被获得。

Highly efficient synthesis of β-amino esters via Mannich-type reaction under solvent-free conditions using ZnCl_2 catalyst

β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives.

A quantum-chemical study on the Mannich reaction with polynitromethanes

According to the results of SCF-CNDO/2 computation, we propose employing the'ladder weighting summation' to define a G_e index which is used to measure the relative magnitudeof the nucleophilicity of the relevant amine and pseudo acid components in a Mannich reaction. Wealso put forward an A_e index to measure the relative magnitude of the electrophilicity of methylene-amine cationic species in the same reaction. A combined use of both G_e and A_e indices is suggestedto evaluate the feasibility of a Mannich reaction for the polynitromethanes and the stability of theproducts. These results are consistent with those conclusions drawn from 'soft-hard acid-basetheory'.

Theoretical Studies on the Mechanism of Mannich Reaction Involving Iminium Salt as Potential Mannich Reagent(4)——Use 2-Methylpropaldehyde as Pseudo-acid Component

以一个真实的Ｍａｎｎｉｃｈ试剂（ＣＨ３）２Ｎ＋ＣＨ２·Ｃｌ－作为研究对象．根据ＡＭ１方法的计算结果，胺、醛及伪酸在中性和酸性介质中的经典Ｍａｎｎｉｃｈ反应的关键步骤的活化能分别为３９０．０和３２１．８ｋＪ／ｍｏｌ．而由新Ｍａｎｎｉｃｈ试剂参与的Ｍａｎｎｉｃｈ反应的关键步骤活化能则为２７８．６ｋＪ／ｍｏｌ．因此新Ｍａｎｎｉｃｈ试剂可以提高反应速率，还分析了新Ｍａｎｎｉｃｈ试剂能降低反应活化能的原因．此外还讨论了另一种可大大降低活化能的新Ｍａｎｎｉｃｈ反应机理本文是研究Ｍａｎｎｉｃｈ反应机理的系列文章之一．