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.     

Three-component condensation of α-nitroacetophenone,aromatic aldehydes,and methylurea

The three-component condensation of aromatic aldehydes, methylurea, and α-nitroacetophenone affords both N(1)-and N(3)-methyl-substituted 4,6-diaryl-5-nitro-3,4-dihydropyrimidin-2(1H)-ones depending on the structure of aldehyde. Intermediate 4,6-diaryl-4-hydroxy-3-methyl-5-nitrohexahydropyrimidin-2-ones and trisubstituted urea, which is the transformation product of the 4-hydroxy-3-methyl derivative in an acidic medium (retro-Henry reaction), were identified in the reaction mixtures. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1141–1145, June, 2007.     

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.     

Three-component condensation in the synthesis of substituted tetrahydropyridinethiolates

Multicomponent cyclocondensation of Meldrum's acid, 2-chlorobenzaldehyde, and N-(4-bromophenyl)-3-amino-3-thioxopropanamide in the presence of N-methylmorpholine afforded N-methylmorpholinium 3-[N-(4-bromophenyl)carbamoyl]-4-(2-chlorophenyl)-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolate in 65% yield. When treated with dilute HCl, the thiolate easily transformed into N-(4-bromophenyl)-4-(2-chlorophenyl)-2-oxo-6-thioxopiperidine-5-carboxamide, which reacted with alkyl halides to give products of regioselective S-alkylation in high yields. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1297–1298, May, 2005.     

Some properties of nitrogen heterocycles synthesized from arylamines and cyclic ketones

The mobilities of the hydrogen atoms of the methylene groups of l,2,3,4-tetrahydroacridine-10-carboxylic acid and of ,-trimethyllenecinchoninic acid on condensation with some aldehydes and ketones of the aliphatic, aromatic, and heterocyclic series and with phthalic anhydride have been studied.     

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.     

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.     

Microwave-assisted aldol condensation of benzil with ketones

Under microwave irradiation,the corresponding hydroxycyciopentenones were prepared in high yields by the cross-aldol reactions of benzil with various ketones.When the reactions were performed in vailOUS solvents under classical heating for a long time,they produced the products in relatively low yields.     

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.     

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.     

The condensation of 1-morpholinocyclohexene with mannich ketones

Summary By the reaction of 1-morpholinocyclohexene with 1-diethylaminobutanone-3 and 1-diethylaminopentanone-3, with subsequent treatment with hydrochloric acid, ^1,8a-octalone-2 and 1-methyl-^1,8a-octalone-2 were obtained in yields of 40 and 66%.     

A novel three-component reaction of 1, 1-dicyano-2-(trifluoromethyl)ethylenes,primary arylamines,and ketones

1, 1-Dicyano-2, 2-bis(trifluoromethyl)ethylene and 3, 3-dicyano-2-(trifluoromethyl)acrylates react with primary arylamines in the presence of ketones to form 1, 1-aryl-1, 4-dihydropyridme derivatives under mild conditions. The mechanism of this three-component reaction includes the formation of Schiffs bases as intermediates. 1, 4-Dihydropyridine derivatives, which are the products of three-component heterocyclization, were also obtained by reaction the corresponding Schiffs bases with 1, 1-dicyano-2-(trifluoromethyl)ethylenes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 552–559, March, 1993.For preliminary communication see Ref. 1.     

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.     

Concerning the products obtained from the condensation of 4-methyl-4-penten-2-ol with benzaldehyde

The products formed in the condensation reaction of4-methyl-4-penten-2-ol with benzaldehyde were reinvcstigated. Their constitutions and configurations were determined spectroscopically. For further characterisation, the three olefins 8–10 were epoxidised.     

Iodine-catalyzed cycloalkenylation of dihydroquinolines and arylamines through a reaction with cyclic ketones under neat conditions

An iodine-catalyzed direct cycloalkenylation of dihydroquinolines and arylamines has been developed. This method consists of a Friedel–Crafts reaction between dihydroquinolines (or arylamines) and cyclic ketones in which the double bond is selectively generated throughout the course of the reaction resulting in a direct cycloalkenylation, under neat conditions.