Doebner condensation in ionic liquids [Bmim]BF_4 and [Bpy]BF_4 to synthesize α,β-unsaturated carboxylic acid

Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.

Poly Ethylene Glycols as Efficient Media for the Synthesis of <i>β</i>-Nitro Styrenes from <i>α</i>, <i>β</i>-Unsaturated Carboxylic Acids and Metal Nitrates under Conventional and Non-Conventional Conditions

Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.

DMAP-Catalyzed [4＋2] Cycloaddition of α,β-Unsaturated Carboxylic Acids with Ketones for Synthesis of ,β-Unsaturated δ-Lactones （pages 397–400）

The DMAP-catalyzed [4＋2] cycloaddition of α,β-unsaturated carboxylic acids with ketones furnishing α,β-unsaturated δ-lactones in good yields （up to 80%） is described, which is the first example of remote -C（sp^3）-H activation of α,β-unsaturated carboxylic acids facilitated by DMAP, a pyridine-based catalyst.

Chemoselective Catalytic Hydrogenation of α,β-Unsaturated Ketones and α,β-Unsaturated Carboxylic Esters

The effect of catalysts P-2 00-Ni(Nickel boride) and P-2 00-Ni-M(M: Co, Fe, Cu, Sn), prepared by adopting a modified recipe, on the chemoselective hydrogenation of carbon carbon double bonds in α,β- unsaturated ketones, and the activity of catalysts P-1.80-Ni, P-2 00-Ni or P-1.80(2 00) -Ni-M(M: Pd, Co, Cu) in the selective hydrogenation of carbon carbon double bonds in α,β-unsaturated carboxylic esters, were investigated systematically. According to the experimental results, the selectivities of these catalysts toward the hydrogenation of the carbon carbon double bonds of α,β-unsaturated keones or α,β-unsaturated carboxylic esters are 96%—100% or 100%, respectively.

Decarboxylative bromination of α,β-unsaturated carboxylic acids via an anodic oxidation

A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation.In this method,ammonium bromide was employed as a bromine source and the reaction features transition-metal-free,short time,and no additional supporting electrolyte.

C(sp^3)–H bond functionalization of non-cyclic ethers by decarboxylative oxidative coupling with α,β-unsaturated carboxylic acids

A copper-catalyzed decarboxylative oxidative coupling of α,β-unsaturated carboxylic acids with non-cyclic ethers is developed.This method provides a new approach for C(sp^3)–H bond functionalization of non-cyclic ethers. Mechanism study shows the reaction involves a radical process.

Corrosion inhibition of α,β-unsaturated carbonyl compounds on steel in acid medium

Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.

Theoretic Simulation of Pr^(3+) and Nd^(3+) Complexes with αHydroxyl Carboxylic Acids

The potential energy difference of trivalent Pr/Nd complex ions with various α hydroxyl carboxylic acids were computed by molecular mechanics plus(MM +) model. Its relationships with the steric hindrance of the coordinating lignads and with the separation factor of Pr/Nd were discussed. It is found that the MM + model can be used for selecting and designing ligand as effective eluant, with which Pr 3+ and Nd 3+ can be separated by ion exchange chromatography.

Enabling heterogeneous catalysis to achieve carbon neutrality: Directional catalytic conversion of CO_(2) into carboxylic acids

The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable conditions.Recently,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value chemicals.The purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal catalysis.Special attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance catalysts.In addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic activity.Finally,challenges and prospects are provided for the future development of this field.It is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs.

Stereoselective electrochemical carboxylation ofα,β-unsaturated sulfones

As an attractive C1 synthon,carbon dioxide(CO_(2))has been extensively used in organic synthesis to produce carboxylic acids.In this research,stereoselective electrochemical carboxylation ofα,β-unsaturated sulfones has been developed under transition-metal-free conditions.All the cinnamic acids and the derivatives are obtained selectively in the E-configuration.Besides,arylpropiolates also can be produced from alkynyl sulfones.

Synthesis of Chiral α-Benzyl-β^(2)-hydroxy Carboxylic Acids through Iridium-Catalyzed Asymmetric Hydrogenation of α-Oxymethylcinnamic Acids

An asymmetric hydrogenation of α-oxymethylcinnamic acids was developed by using chiral spiro phosphineoxazoline/iridium complexes as catalysts to prepare β^(2)-hydroxycarboxylic acids with high reactivity(TON up to 2000)and excellent enantioselectivity(up to 99.5%ee).By using this highly efficient asymmetric hydrogenation as a key step,a concise total synthesis of natural product homoisoflavone(S)-(+)-4 was accomplished.

Synthesis and Crystal Structure of a Copper(II) Complex with α-Hydroxylated Acid, [Cu(C_(14)H_8O_3)(C_5H_(13)NO)(H_2O)].0.5H_2O

The complex monoaqua[(9-hydroxy-fluorene-9-carboxylato)(N,N-Dimethylisopro- panolamine)]copper(II) semihydrate, Cu(C14H8O3)(C5H13NO)(H2O)]0.5H2O (Mr = 417.93), crystallizes in triclinic system, space group P with a = 9.846(2), b =12.419(3), c =16.781(3)? =75.55(3), b = 75.00(3), g = 84.58(3), V =1918.5(7)?, Z = 4, F(000) =872, Dc=1.45g/cm3 and m= 1.17mm-1. The final R and wR are 0.0481 and 0.1427 for 7099 observed reflections, respectively. The coordination polyhedron around the copper atom is a distorted square pyramid, the basal plane consisting of one carboxyl oxygen atom and one -hydroxylated oxygen atom from a 9-hydroxy-fluorene-9-carboxylato ligand, one nitrogen atom and one oxygen atom from the N,N-dimethylisopropanolamine ligand; while the axial coordination site is occupied by a water oxygen atom with a Cu-O bond length of 2.428(3)?

Synthesis,thermal decomposition and crystal structure of copper(Ⅱ)α,β-unsaturated carboxylate with urea

A detailed synthesis is described for binuclear cage ternary complexes Cu2A4 [（NH2）2CO]2, where A = CH2 =CH—COO- and CH2 =C（CH3）—COO-. Elemental analysis and thermal analysis have been investigated. The molecular structure of Cu2 （CH2 = CH—COO）4[（NH2）2CO]2 was determined by single crystal X-ray diffraction. The material forms blue crystal with tetragronal symmetry, space group P42/n, a = b = 1. 239 35（6） nm, c = 1. 398 05 （16） nm, Z = 4. There exists, a magnetic exchange interaction between the two paramagnetic Cu atoms. The Cu—Cu bond length is 0.260 94 nm.

Syntheses,characterization,crystal structure and magnetic properties of copper(Ⅱ) α,β-unsaturated carboxylate complexes with trimethyl phosphate

Two ternary complexes Cu2A4[OP(OCH3)3]2 (A represents CH2=CH-COO- and CH2=C(CH3)-COO-) have been synthesized, and elemental analyses, IR, ESR, electronic reflectance spectra and magnetic studies were carried out. The single crystal X-ray diffraction shows that Cu2[CH2=C(CH3)-COO]4[OP(OCH3)3]2 is triclinic, with space group P1, a = 1.05128(13), b = 1.7559(5), c = 1.94479(3) nm, α =91.263(14)°,(β = 102.559(6)°,γ= 106.339(13)°, Z = 4 and R = 0.0668. Two copper(Ⅱ) atoms are bridged by four (a-methacrylate groups, and each copper(Ⅱ) atom is coordinated with a trimethyl phosphate molecule in the axial position, forming a distorted square pyramidal configuration. The symmetric center is between the two copper(Ⅱ) atoms, and the Cu-Cu bond distance is 0.26098(6) nm. The Cu-Cu distance and magnetic studies suggest that there exist anti-ferromagnetic interactions between the two copper(Ⅱ) atoms.

One-step synthesis of α,β-unsaturated arylsulfones by a novel multicomponent reaction of aromatic aldehydes,chloroacetonitrile,benzenesulfinic acid sodium salt

A new and green method for the synthesis of α,β-unsaturated arylsulfones had been achieved through the condensation of aromatic aldehydes, chloroacetonitrile, benzenesulfinic acid sodium salt in the presence of 1-butyl-3-methyl imidazolium hydroxide （[bmim]OH） in EtOH under reflux. The ionic liquid was recovered and recycled for subsequent reactions. The advantages of this protocol were non-toxic, easy work-up and good yields.

Two New Phenolic Carboxylic Acid Esters from Opuntia vulgaris

Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.

α,β-不饱和羧酸参与的脱羧二氟烷基化反应研究进展

含氟化合物在医药、农药和材料等领域发挥着不可缺少作用。其中,二氟亚甲基(-CF2-)具有很好的代谢稳定性,可以改善有机分子的物理和化学性质,具有提高有机分子的代谢稳定性和生物利用度等特点。因此,向有机分子中引入二氟甲基在氟化学领域备受关注。α,β-不饱羧酸具有稳定的化学性质和物理性质,其参与的二氟烷基化反应已取得显著发展。整理了到目前为止α,β-不饱羧酸参与的二氟烷基化反应,并从过渡金属催化和可见光催化两方面对该类型反应进行归纳总结。

1,2-Dibromoethane and KI mediated α-acyloxylation of ketones with carboxylic acids

The 1,2-dibromoethane-and Kl-mediatedα-acyloxylation of ketones is reported in moderate to good yield without the use of transition metals and strong oxidants.Various acids are well tolerated with wide functional group compatibility.An 1,2-dibromoethane-and Kl-catalysed reaction mechanism is proposed based on the results of control experiments.

Divergent pathways of β,γ-unsaturated α-diazocarbonyl compounds catalyzed by dirhodium and Lewis acids catalysts separately or in combination

β,γ-Unsaturated a-diazocarbonyl compounds possess two reactive sites for electrophilic addition-one at the diazo carbon and the other at the vinylogous γ-position.Controlled by catalyst,divergent transformations are achieved starting from the same starting materials,either by Lewis acid-catalyzed addition or by dirhodium-catalyzed metal carbene reactions.In select cases two catalysts working in combination or in sequence provide a relay for cascade transformations.In this review,we summarize advances in catalyst-dependent divergent transformations of β,γ-unsaturated α-diazocarbonyl compounds and highlight the potential of this exciting research area and the many challenges that remain.

Resolution of racemic R.S-α-arylethylamine by a new resolving agent (R)thiazolidine-2-thione-4-carboxylic acid

Racemic R.S-α-arylethylamine was resolved by R (-) thiazolidine-2-thione-4-carboxylic acid, a new resolving agent abbreviated as [R (-) TTCA], by which R (-) TTCA.S(-) arylethylamine salts2a-2e, [α] D 20 =-47.24° — 64.40° and optically active R(+)-a-arylethylamines3a – 3e, 74. 54%-94. 45% e, e., were obtained. Optically active S (-) -α-arylethylamines4a-4e, 72.84%-90.36% e.e., were obtained by the decomposition of2a-2e in basic solutions. The influence of substitutive group of the benzene ring on the basicity of the amino group was studied by semiempirical PM3 method. The structures of the R (-) TTCA.S (-) -α-phenylethylamine salt (2a(R-S) configuration) and R (-) TTCA-R(+)-a-phenylethylamine salt (2a(R-R) configuration) have been established by means of X-ray diffraction. They crystallize in a monoclinic system. Space group isP21. The cell constants of2a(R-S) configuration were obtained as follows: α = 1.387 8(2), b = 0.664 05(101,c = 1.580 O(2) nm; β = 90.844(10)° Z = 4; those obtained for2a(R-R) configuration were α = 1.080 6(2),b = 0.584 80(12),c = 1.2188(2) nm, β= 110.38(3)dg, V = 0.7220nm3,Z = 2. There are intermolecular hydrogen bonds in the crystals of the two kinds of configurations of the amine salt. The hydrogen bond number in the unit cell of R (-) TTCA.S (-)-α-phenylethylamine salt is twice as much as that of R (-) TTCA.R(+)-a-phenylethylamine salt.