tBuOLi-Mediated Alkynylation of Aldehydes

The lithium tert-butoxide reagent was found to promote the addition of terminal aromatic alkynes to various aromatic aldehydes. This reaction was efficiently carried out in anhydrous dimethylformamide at room temperature in air for 50 min, and the corresponding propargylic alcohols were obtained in good to excellent yields (up to 95%).

Beryllium-Induced Conversion of Aldehydes

Aldehydes play a key role in the human metabolism. Therefore, it is essential to know their reactivity with beryllium compounds in order to assess its effects in the body. The reactivity of simple aldehydes towards beryllium halides (F, Cl, Br, I) was studied through solution and solid-state techniques and revealed distinctively different reactivities of the beryllium halides, with BeF₂ being the least and BeI₂ the most reactive. Rearrangement and aldol condensation reactions were observed and monitored by in situ NMR spectroscopy. Crystal structures of various compounds obtained by Be²⁺-catalyzed cyclization, rearrangement, and aldol addition reactions or ligation of beryllium halides have been determined, including unprecedented one-dimensional BeCl₂ chains and the first structurally characterized example of an 1-iodo-alkoxide. Long-term studies showed that only aldehydes without a β-H can form stable beryllium complexes, whereas other aldehydes are oligo- and polymerized or decomposed by beryllium halides.     

Synthesis of Difluoromethylthioesters from Aldehydes

Difluoromethylthioester compounds are yet another important kind of organofluorine compound and are reported here for the first time. They can be efficiently synthesized from various aldehydes. The synthetic method features mild reaction conditions, good tolerance of functional groups, broad substrate scope, and importantly, no metal is involved in the reaction. The approach has the potential to become an important tool for the late‐stage functionalization of advanced synthetic intermediates, and should have many applications in medicinal chemistry.     

Iridium-Catalyzed Formyl-Selective Deuteration of Aldehydes

We report the first direct catalytic method for formyl-selective deuterium labeling of aromatic aldehydes under mild conditions, using an iridium-based catalyst designed to favor formyl over aromatic C−H activation. A good range of aromatic aldehydes is selectively labeled, and a one-pot labeling/olefination method is also described. Computational studies support kinetic product control over competing aromatic labeling and decarbonylation pathways.     

Reaction of Hexamethyldisilazane with Aldehydes

Russian Journal of General Chemistry -     

Mesoionic Carbene-Catalyzed Formyl Alkylation of Aldehydes

Ketones are among the most useful functional groups in organic synthesis, and they are commonly encountered in a broad range of compounds with various applications. Herein, we describe the mesoionic carbene-catalyzed coupling reaction of aldehydes with non-activated secondary and even primary alkyl halides. This metal-free method utilizes deprotonated Breslow intermediates derived from mesoionic carbenes (MICs), which act as super electron donors and induce the single-electron reduction of alkyl halides. This mild coupling reaction has a broad substrate scope and tolerates many functional groups, which allows to prepare a diversity of simple ketones as well as bio-active molecules by late-stage functionalization.     

Microwave Assisted Oxidation of Aromatic Aldehydes

Aromatic aldehydes are converted to carboxylic acids in 6-8 minutes, and in the absence of any external promoting agent, under microwave irradiation conditions.     

Reactivity of Polysaccharide Aldehydes toward N-Nucleophiles

The conversion of aldehyde groups in polysaccharide aldehydes to azomethine groups in reactions with amines and hydrazine derivatives was studied in relation to the structure of polysaccharide aldehyde and reaction conditions.     

Salting-out chromatography : Aldehydes and Ketones

Mixtures of aldehydes and/or ketones have been separated by salting-out chromatography. The effects of such variables as sample size, flow rate, concentration of the eluent, cross-linking, mesh size, and type of resin on the elution behavior of the compounds were studied. Salting-out parameters were determined for thirteen ketones and four aldehydes. The differential pH method of Roe and Mitchell is applicable to the determination of carbonyl compounds in aqueous salt solutions.     

Spectrophotometric Determination of Some Aromatic Aldehydes

Abstract

A spectrophotometric quantitative determination method of aromatic aldehydes via interaction with diphenylamine in the presence of 5N hydrochloric acid was developed. The colored products obtained display maximum absorption at λ = 590-640 nm, E_cm ^1% in the range 50-410, and a concentration range of 5-75 μg/ml. The effects of time, concentration and temperature on the nature of reaction products were investigated. Various other organic compounds do not interfere.     

Aldehydes as Alkylating Agents for Ketones

Common and non-toxic aldehydes are proposed as reagents for alkylation of ketones instead of carcinogenic alkyl halides. The developed reductive alkylation reaction proceeds in the presence of the commercially available ruthenium catalyst [(cymene)RuCl₂]₂ (as low as 250 ppm) and carbon monoxide as the reducing agent. The reaction works well for a broad substrate scope, including aromatic and aliphatic aldehydes and ketones. It can be carried out without a solvent and often gives nearly quantitative yields of the products. This straightforward and cost-effective method is promising not only for laboratory application but also for industry, which produces carbon monoxide as a large-scale waste product.     

L-脯氨酸催化的硝基烷烃与醛的缩合反应

研究了氨基酸催化的硝基烷烃与醛的缩合反应。以L-脯氨酸(5%~20%)为催化剂,高产率(77%~95%)地合成了一系列硝基烯烃类化合物,其结构经1H NMR,IR和MS表征。     

Aldehydes of the dibenzene chromium series

Conclusions Bis-(-benzoylvinylbenzene)chromium and bis(ethylcinnamate) chromium have been obtained by the condensation of bis(benzaldehyde)chromium with acetophenone and ethylacetate in an alkaline medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 922–924, April, 1976.The authors express their gratitude to P. V. Petrovskii and V. A. Svoren' for recording the paramagnetic resonance spectra, Yu. S. Nekrasov and N. I. Vasyukova for recording the mass spectra, and B. V. Lokshin for recording the infrared spectra.     

Azomethines Based on Pyridoxal-Derived Aromatic Aldehydes

The reaction of pyridoxal with 2,4-dihydroxybenzaldehyde in a hydrochloric acid solution gave 1-(5-formyl-2,4-dihydroxyphenyl)-7-hydroxy-6-methyl-1,3-dihydrofuro[3,4-c]pyridin-5-ium chloride. Treatment of the latter with sodium hydride in ethanol afforded a free aldehyde in 85% yield. A series of azomethines and imidazolidines was obtained by reacting the obtained aldehyde with various amines and diamines.     

N-乙氧羰基亚甲基苯甲亚氨酸乙酯与脂肪及醛的反应

在氨基酸合成方法研究中,我们已经报道了 N-乙氧羰基亚甲基苯甲亚氨酸乙酯及 N-氰甲基苯甲亚氨酸乙酯的烷基化和 Micheal 加成反应,从而合成了一系列碳链增长的α-氨基酸。本文报道亚氨酸酯(1)与脂肪醛(2)在固液相转移催化条件下的反应。产物经快速柱层析分离,得到一对非对映异构体——顺式和反式(口恶)唑啉酯(3～7),(口恶)唑啉酯在盐酸中水     

Reaction of Tribenzylphosphine Oxide with Aldehydes

Tribenzylphosphine oxide readily and stereoselectively reacts with aliphatic, aromatic, and heteroaromatic aldehydes in the presence of strong bases yielding exclusively (or predominantly) E-isomers of 1-organyl-2-phenylethenes and dibenzylphosphinic acid.