Studies of the condensation of sulfones with ketones and aldehydes

[reaction: see text] The condensation of ketones or aldehydes with sulfones was shown to give a variety of products. Condensation of 2-methylcyclohexanone with dimethyl sulfone using potassium t-butoxide as base gave useful yields of 1,2-dimethylenecyclohexane. Under the same conditions, cycloheptanone, 3-methyl-2-butanone, and 2-butanone were converted to dienes. Remarkably, these reaction conditions converted acetophenone into p-terphenyl (10%) and (E)-1,4-diphenyl-3-penten-1-one (44%). Propiophenone was converted to 2'-methyl-p-terphenyl (61%). Using alpha-tetralone produced 1-methynaphthalene and naphthalene. No reaction took place with beta-tetralone. Using diethyl sulfone with alpha-tetralone lead to pure naphthalene. Condensation of isobutyraldehyde and dimethyl sulfone using potassium t-butoxide gave isoprene in low yield. Using benzaldehyde and benzyl phenyl sulfone in N,N-dimethylacetamide gave 1,2-diphenyl-1-phenylsulfonylethylene, N,N-dimethylcinnamide, and a complex condensation product. Only 1,2-diphenyl-1-phenylsulfonylethylene was obtained when the solvent was THF.     

Molybdenum hexacarbonyl-catalyzed condensation of malononitrile with ketones and aldehydes

Molybdenum hexacarbonyl activated with pyridine or morpholine catalyzes the condensation of malononitrile with ketones and aldehydes at 140 °C, which leads to alkylidenemalononitriles in 75–100% yield.     

Three-component condensation of hetarylguanidines with aldehydes (ketones) and dicarbonyl compounds

The three-component condensation of benzoxa(thia)zolylguanidines, aldehydes (ketones), and β-dicarbonyl compounds (acetyl-and benzoylacetone, ethyl acetoacetate, acetoacetanilides, cyclohexanedione-1,3 and its derivatives) has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1549–1554, October 2006.     

Direct synthesis of Cbz-protected β-amino ketones by iodine-catalyzed three-component condensation of aldehydes, ketones and benzyl carbamate

Iodine has been found to be very effective catalyst for a Mannich reaction between an aryl aldehyde, an aryl ketone and benzyl carbamate, even though this is a less reactive amine, to produce Cbz-protected β-aryl β-amino carbonyl compounds in high yields.     

The Darzens condensation of α,β-unsaturated aldehydes and ketones

The one-pot Darzens condensation of α,β-unsaturated aldehydes and ketones with enolates of an α-bromo ester or ketone is described.     

Selective synthesis of alpha,beta-unsaturated ketones by dibutyltin dimethoxide-catalyzed condensation of aldehydes with alkenyl trichloroacetates

Various alpha,beta-unsaturated ketones were stereoselectively synthesized in high yields up to 94% by a condensation reaction between alkenyl trichloroacetates and aldehydes using dibutyltin dimethoxide as a catalyst in the presence of methanol. This process is superior to the classical Claisen-Schmidt condensation with respect to mildness of the base catalyst and product selectivity.     

Synthesis of sterically hindered enamides via a Ti-mediated condensation of amides with aldehydes and ketones

The first TiCl(4)-mediated condensation of secondary amides with aldehydes and ketones has been achieved. The reaction proceeds at room temperature and is complete within 5 h in most cases. The optimized procedure used 5 equiv of an amine base hinting that the in situ activation of both the amide and the Lewis acid is required. The reaction affords polysubstituted (E)-enamides.     

Structures and some properties of the products of condensation of phthalazone hydrazones with aldehydes and ketones

The products of condensation of 2-H-phthalazone hydrazones with carbonyl compounds in solution and in the crystalline form have phthalazone ylidenehydrazone (unsymmetrical azine) rather than phthalazinylhydrazone I structures, as has previously been assumed. 2-H-Phthalazone arylidenehydrazones exist in the EE form, and their analogs methylated in the 2-N position of the phthalazone ring exist in the ZE' form. Facile ZE' ZZ' isomerization was noted for 2-methyl-4-chlorophthalazone ethylenehydrazone in halogen-containing solvents. Its unmethylated analog — 4-chlorophthalazone ethylenehydrazone (VIIIb) — is a mixture of geometrical isomers (EE'/EZ'=31).Communication LIX from the series Hydrazones. See [1] for communication LVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 690–698, May, 1978.     

Synthetic talc as a solid base catalyst for condensation of aldehydes and ketones

Magnesium organo silicates (MOSs; synthetic talc) as such and with amine surface functionalities were synthesized by sol–gel method under non-hydrothermal conditions and characterized by spectroscopic techniques. The synthesized talc samples were observed to be thermally stable up to 200 °C in nitrogen atmosphere and used as catalysts for condensation of aldehydes and ketones. Application of synthetic talc as a solid base catalyst for condensation of aldehydes and ketones is being reported for the first time. The effect of solvent, solvent to reactant molar ratio, amount of catalyst and temperature was studied in detail for self-condensation of propanal. High conversion (86%) of propanal with 95% selectivity of 2-methylpentenal was achieved using dimethyl sulphoxide as a solvent. The kinetic study was carried out for the condensation of propanal catalyzed by amine functionalized MOS under optimum reaction conditions. Catalyst was re-used without significant loss in activity up to three cycles.     

Structure of the condensation products of 3-sulfanylpropionic acid hydrazide with aldehydes,ketones, and aldoses

Condensation products of aliphatic aldehydes with 3-sulfanylpropionic acid hydrazide exist in solution as mixtures of linear hydrazone and cyclic 1,3,4-thiadiazepine tautomers. Hydrazones derived from 3-sulfanylpropionic acid hydrazide and aromatic aldehydes and ketones have mostly linear structures of different stereoisomers arising from Z-E isomerism with respect to the double C=N bond and restricted rotation about the C(O)-N bond. Condensation products of 3-sulfanylpropionohydrazide with a series of aldoses give rise to ring-chain-ring tautomeric equilibrium between α,β-isomeric pyranose structures, open-chain aldose hydrazone tautomer, and two diastereoisomeric seven-membered cyclic 1,3,4-thiadiazepine forms.     

Regioselectivity in the cross condensation of α,β-unsaturated aldehydes and methyl ketones promoted by magnesium phenoxides

“Kinetic selectivity” in the cross condensation of α,β-unsaturated aldehydes and methyl ketones are obtained using 2,4,6-trimethylphenoxymagnesium bromide (2,4,6-TMPOMgBr) in benzene as catalyst.     

Solvent-free condensation of arylacetonitrile with aldehydes

The condensation of a series of arylacetonitriles with aldehydes can be carried out by mixing equivalent amounts of reagents with neat powdered KOH at room temperature for 3-60 min depending on the aldehyde steric hindrance. At higher temperature (110 °C), yields were generally higher and purity increased within very short reaction times (1-5 min). With pentamethylphenylacetonitrile, a phase transfer agent was necessary to give a satisfactory yield.     

Condensation of aldehydes and ketones

The Mannich reaction with methylene- and benzylidenediacetophenones has given: 1,3-dibenzoyl-4-piperidinobutane, 1,3-dibenzoyl-4-morpholinobutane, 1,3-dibenzoyl-4-diethylamino-2-phenylbutane, 1,3-dibenzoyl-2-phenyl-4-piperidinobutane, 1,3-dibenzoyl-4-diethylaminobutane, and 1,3-dibenzoyl-4-dimethylamino-2-phenylbutane. From the latter two compounds, 3-diethylaminomethyl-2,6-diphenylpyridine and 3-dimethylaminomethyl-2,4,6-triphenylpyridine have been obtained.For part XVII, see [7].     

Reduction of aldehydes and ketones by transfer hydrogenation with 1,4-butanediol

1,4-Butanediol has been used as the hydrogen donor in transfer hydrogenation reactions. The equilibrium is driven by the formation of gamma-butyrolactone, and the diol is therefore not required in excess.     

Condensation of aldehydes and ketones

The alkaline condensation of β-aceto-and β-propionaphthalenes with furfural has given, respectively, 2-(α-furfuryl)-1, 3-di(β-naphthoyl)-propane and 3-(α-furyl)-2,4-di(β-naphthoyl)pentane; both δ-diketones have also been obtained by the Michael condensation. Under more severe conditions, two molecules of furfural condense with three molecules of β-acetonaphthalene to form 2, 4-di(α-furyl)-1, 3, 5-tri(β-naphthoyl)pentane. Under similar conditions, benzaldehyde exhibits only a feeble capacity for triketone condensation with β-acetonaphthalene. The condensation of β-propionaphthalene with furfural has given the new compound furylidenepropionaphthalene. It has been shown that both under the conditions of the improved Chichibabin pyridine synthesis and under the conditions of the Leuckhardt reaction, 3-(α-furyl)-1, 3-di(β-naphthoyl)propane gives 4-(α-furyl)-2, 6-di(β-naphthyl)pyridine.     

Reductive coupling of isatins with ketones and aldehydes by low-valent titanium

The reductive coupling of isatins with ketones and aldehydes by Zn–TiCl₄ in THF gave two- and four-electron reduced products, 3-hydoxy-3-(1-hydoxyalkyl)oxindoles and 3-alkylideneoxindoles, selectively by controlling the reaction conditions. Although the 3-(1-hydoxyalkyl)oxindoles were also produced as the four-electron reduced products in some cases, these products were readily dehydrated to 3-alkylideneoxindoles. The 3-alkylideneoxindoles derived from aldehydes were formed as mixtures of geometric isomers. The both geometric isomers were isomerized to the equilibrium mixtures by reflux in cat. PPTS/benzene.     

Reactions on a surface. 2. Role of oxides in condensation of 3-methyl-3-buten-1-ol with aldehydes and ketones

The formation of di- and tetrahydropyrans on an oxide surface in the reaction of 3-methyl-3-buten-1-ol with carbonyl compounds is due primarily to the adsorptive properties of the surface itself, Lewis acid centers hardly catalyzing this reaction at all under the conditions being considered.See [1] for Communication 1 of the series.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 183–186, February, 1990.