Structures of the products of condensation of phthalazone hydrazones with mesityl oxide

It was established on the basis of data from the UV and PMR spectra, the dipole moments, and the synthesis of fixed structures that the products of the condensation of phthalazone hydrazones with mesityl oxide have the structures of mixed phthalazone azines and mesityl oxide rather than the phthalazinylhydrazone structure that was previously assumed for them.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 678–683, May, 1981.     

The reaction of lead tetraacetate with unsubstituted hydrazones of some aromatic ketones and aldehydes

N-Unsubstituted hydrazones of some aromatic ketones and aldehydes were found to react with lead tetraacetate giving the corresponding diazo compounds as primary reaction products, and the derived 1-monoacetoxy- and 1,1-diacetoxy-1-arylalkanes, as well as azines, as final products. The yields obtained depend on the stability of the diazo compound initially formed and on the experimental conditions employed (amount of lead tetraacetate, presence of acid or base). Mechanisms for the formation of products are discussed.     

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.     

Synthesis of pyrazolines by the condensation of monoalkyl hydrazones with aldehydes

Acetaldehyde readily condenses with its monalkyl hydrazones with the formation of 1-alkyl-5-methyl-2-pyrazolines. A number of pure 2pyrazolines have been synthesized in this way with yields of 40–60%. In the condensation of propionaldehyde with its isopropyl hydrazone, because of the occurrence of rearrangements and the nonstereospecificity of the process, a mixture of structural and stereoisomeric 2-pyrazolines is formed. The promising condensation of aldehydes with monalkyl hydrazones of other aldehydes and ketones is accompanied by transhydrazonation, which limits the preparative possibilities of this reaction.From the text of the thesis of N. B. Burmanova, defended in May, 1967.     

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.     

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.     

Knoevenagel condensation products from some cyclic ketones : Structure and stereochemistry

NMR spectra are used to determine the stereochemistry of the Knoevenagel condensation products of type I. Correct structures are given for the products of condensation between ethyl cyanoacetate and isatin, indan-1-one, or indan-2-one; and between α-tetralone and cyano-acetamide.     

A convenient method for the preparation ofN-unsubstituted hydrazones of aromatic ketones and aldehydes

A general and useful method for the synthesis ofN-unsubstituted hydrazones of aromatic ketones and aldehydes in good yields was elaborated. The use of a large excess of hydrazine hydrate and catalytic amounts ofp-toluenesulfonic acid makes it possible to prepare the hydrazones without an admixture of the corresponding azine. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2197–2199, November, 1999.     

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.     

Studies with dithizone--XII. Formation of thiadiazolines by condensation with aldehydes and ketones

The red colour that develops when mineral acids are added to solutions of dithizone (I; 3-mercapto-1,5-diphenylformazan) in certain samples of dioxan is mainly due to the formation of 2-methyl-3-phenyl-5-phenylazo-1,3,4-thiadiazoline (II) derived in part from adventitious traces of 2-methyldioxalane. A purple compound of molecular formula C(13)H(10)N(4)S is also formed from (I) by an independent and slower reaction. The thiadiazoline (II) is readily prepared from (I) and acetaldehyde, but analogous compounds from formaldehyde benzaldehyde, acetone and ethyl methyl ketone are obtained in better yield by starting from diphenylthiocarbazide. Di-p-tolyldithizone gives similar reactions. Reduction of the thiadiazoline (II) [which has spectra very closely resembling those of 1:1 complexes of (I) with arylmercury (II) cations] with ammonium hydrogen sulphide in ethanol yields diphenylthiocarbazide by opening of the hetero-ring and elimination of an alkyl residue from the intermediate 3-alkylmercapto-1,5-diphenylformazan. Other examples of nucleophilic displacements from the formazan group by SH(-) have been investigated.     

Kinetics of the condensation of urea with some aliphatic aldehydes

The rate and equilibrium constants of the condensation of urea with some aliphatic aldehydes to form alkylidenediureas have been measured spectrophotometrically in aqueous solutions at 24·2°. The rate is always expressed as: v = k[H₂NCONH₂][free RCHO]. Electron-releasing groups in aldehydes tend to decrease the rate of forward reaction with Taft's ρ^* value of +3·5. The reaction is reversible and is subject to both acid and base catalysis. The Brönsted catalysis law, κ_A = G_AK_A^α, is applicable to the acid catalysis, and the α values in the equation are 0·38 for propionaldehyde, 0·43 for n-butyraldehyde, and 0·45 for isobutyraldehyde. These results agree with the expectation from the suggested reaction mechanism involving the rate-determining attack of urea on free aldehyde molecule.     

Luminescence and photochemical properties of hydrazones of aromatic aldehydes

Luminescence and photochemical properties found by us earlier for several hydrazones of aromatic aldehydes have been shown to be characteristic also of other compounds of this class. The structure of the product of reversible photochemical reaction of hydrazones of aromatic aldehydes is explained by specific interactions between the lone electron pairs of the two vicinal nitrogen atoms in the molecule of hydrazine. Compounds possessing photochromic properties have been suggested and prerequisites of application of luminescent hydrazones as luminophors have been formulated.     

Macrocyclic condensation products of indole and simple aldehydes

Under strongly acid conditions the reaction between indole or 1-methylindole with formaldehyde gives cyclooligomeric products in small yields. The corresponding products are also formed by simple acid treatment of 3,3′-diindolylmethane and 3,3′-di(1-methylindolyl)methane. The reaction between indole and aromatic aldehydes gives dimeric products.