Condensation products of 2-bromo-3-substituted-inden-1-ones with several primary amines

2-Bromo-3-substituted-inden-1-ones 2 reacted with L-cysteine or 2-aminobenzenethiol to produce 2,3-dihydro-5-phenylindeno[2,1-b][1,4]thiazine in moderate yield or 6-substituted-indeno[2,1-b][1,4]benzothiazines in good yield. The debrominated oxime and the phenylhydrazone of 2 were separated into their respective E- and Z-conformers by column chromatography and their E- and Z-configurations were obtained from the ¹H nmr spectra.     

Condensation of substituted 2-aminopyridine with β-ketocarboxylic esters: 4H-pyrido[1,2-a]pyrimidin-4-ones and pyridin-2-ones

We report the condensation of substituted 2-aminopyridines 5 with β-ketocarboxylic esters in polyphosphoric acid. In this reaction were obtained together with the target compounds, 4H-pyrido[1,2-a]pyrirnidin-4-ones 6 also the pyridin-2-ones 7 . All the compounds 7 were tested for their calcium-antagonistic activity but failed to evoke any vasorelaxant response.     

Michael condensation of 3-arylidene-3H-pyrrol-2-ones and 3-arylidene-3H-furan-2-ones with cyclohexanone

The Michael condensation in the series of 5-aryl-3-arylidene-3H-pyrrol-2-ones and 5-aryl-3-arylidene-3H-furan-2-ones, containing an activated C=C bond, with cyclohexanone was investigated. It was shown that the condensation products were 1,5-dicarbonyl compounds containing a heterocyclic fragment. The enolization of one of the oxo groups, leading to the formation of hydroxypyrrole or hydroxyfuran structures, was demonstrated by the spectral data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–827, June, 2007.     

Common and Specific Features of the Michael Condensation in the Series of 3-R-3H-Furan-2-ones

The Michael condensation in the series of 5-aryl-3H-furan-2-ones with chalcones containing electron-donating substituents was studied. In the case of ,-unsaturated ketones containing an electrondonating substituent, the reaction does not stop at the stage of formation of 1,5-dicarbonyl compounds but is accompanied by intramolecular cyclodehydration yielding a new series of furo[2,3-b]-4H-pyrans. A mechanism of formation of these products was suggested. The structure of reaction products was proved by IR and ¹H NMR spectroscopy.     

Condensation of 5-Acetyl-3,4-dihydropyrimidin-2(1H)-ones with Hydrazine

Russian Journal of Organic Chemistry - 3,4-Dihydropyrimidines obtained by the Biginelli reaction react with hydrazine to give a mixture of N-[(3,5-dimethyl-1H-pyrazol-4-yl)(R)methyl]ureas and...     

Condensation of 3,5-Dialkyltetrahydro-4H-thiopyran-4-ones with Formaldehyde

Russian Journal of General Chemistry - The reaction of 3,5-dimethyl- and 5-methyl-3-(2-propyl)tetrahydro-4H-thiopyran-4-ones with formaldehyde without or in the presence of 0.1–0.5 equiv....     

Bromination of 5-Substituted 3H-Furan-2-ones and 3H-Pyrrol-2-ones

The bromination of 5-alkyl(aryl)-3H-furan-2-ones and 5-alkyl(aryl)-3H-pyrrol-2-ones and also their derivatives takes place at the ethylene bond with the formation of 4-monobromo derivatives. N-Phenyl-3H-pyrrol-2-ones are brominated simultaneously at the ethylene bond of the heterocycle and at the phenyl substituent at the nitrogen atom.     

Heterocyclic compounds from 3,3-dimercapto-1-aryl-2-propen-1-ones. Note 3. Condensation with N-methyl-o-phenylenediamine and N-benzyl-o-phenylenediamine

Two seven-membered ring compounds and three five-membered ring compounds were obtained by reaction in hot xylene of 3,3-dimercapto-l-phenyl-2-propen-1-one (1) with N-alkyl-o-phenylenediamines (2) . Compounds isolated were the 4-phenyl-5-alkyl-1,5-dihydro-2H-1,5-benzodiazepine-2-thiones (3) the 1-alkyl-4-phenyl-1,3-dihydro-2H-1,5-benzodiazepine-2-thiones (4) , the 1-alkyl-2-phenacylbenzimidazoles (5) , the 1-alkyl-2-phenylbenzimidazoles (6) and the 1-alkyl-2-methylbenzimidazoles (7) . The structures of these compounds were elucidated from their chemical reactivity and their nmr and ir spectra.     

Cross metathesis with strained exocyclic enones: synthesis of 3-alkylideneoxetan-2-ones from 3-methyleneoxetan-2-ones

[reaction: see text] 3-Alkylideneoxetan-2-ones have been prepared in good to excellent yields with high Z-selectivity by olefin cross metathesis with 3-methyleneoxetan-2-ones in the presence of second generation metathesis catalysts 1 or 2.     

Reaction of 3-arylhydrazono-3H-furan-2-ones with o-phenylenediamine

Depending on the conditions, 3-arylhydrazono-3H-furan-2-ones reacted with o-phenylenediamine along two pathways with formation of 2-hydrazonotetrahydrobenzopyrrolo[1,2-a]imidazol-1-ones and 2-(1-aryl-1H-pyrazol-3-yl)benzimidazoles.     

A novel route to substituted 3-methylidenechroman-2-ones and 3-methylchromen-2-ones

3-Methylidenechroman-2-ones, or their rearrangement products 3-methylchromen-2-ones, were efficiently synthesized by Michael addition of various nucleophiles to 3-diethoxyphosphorylchromen-2-ones followed by Horner-Wadsworth-Emmons reaction of the adducts with formaldehyde. Relative configuration and conformation of the intermediate adducts were studied using NMR spectroscopy and semiempirical PM3 calculations.     

Arylmethylene derivatives of 5-R-3H-furan-2-ones and N-aryl-5-R-3H-pyrrol-2-ones in reaction with acetylacetone

Reaction with acetylacetone in the series of 3-arylmethylene-substituted furan-2-ones and pyrrol-2-ones was studied. 8-R-4-Acyl-5-aryl-3-oxo-9-oxabicyclo[4.3.0]nona-1,7-dienes and N-tolyl-8-R-4-acyl-5-aryl-3-oxo-9-azabicyclo[4.3.0]nona-1,7-dienes were synthesized. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1457–1462, October, 2007.     

Condensation of β-cyclocitral with benzaldehyde

β-Cyclocitral 1b condenses with benzaldehyde in the presence of base catalysts giving the 2-benzopyrans 4, 5 and 6 , and in the presence of acid catalysts giving exclusively the aldehyde 7 . The cyclocitrals 1a and 1b are both isomerized by strong base anion exchange resins, but their aldehyde-protected derivatives 2 and 3 are not. Some tests used to characterize the aldehydes and their condensation products are described.     

1-Organyl-2-azasilatran-3-ones

New 1-organyl-2-azasilatran-3-ones have been synthesized via the reaction of trifunctional silanes RSiX₃ (R = Et, Pr, Ph, CH₂=CH, or ClCH₂; X = Cl or Me₂N) with N,N-bis(2-hydroxyethyl)glycinamides (HOCH₂CH₂)₂NCH₂C(O)NHR (R = H or Me) and their N′,O-trimethylsilyl derivatives. The obtained products can be hydrolyzed to give the corresponding organylsilanetriols. Lithiation of 1-methyl- and 1-phenyl-2-azasilatran-3-ones with n-butyllithium or their reduction with lithium aluminum hydride leads to the products of splitting of the atrane backbone RSiBu₃ and RSiH₃ (R = Me or Ph), respectively.     

Heterocyclic compounds from 3,3-dimercapto-1 -aryl-2-propen-1-ones. Note 2. Condensation with o-aminothophenol and o-aminophenol

The condensation of 3,3-dimercapto-1-phenyl-2-propen-1-one with o-aminothiophenol and o-aminophenol in hot xylene gave 2-phenacylbenzothiazole ( 3 ) and 2-phenacylbenzoxazole ( 5 ). When the reaction with o-aminophenol was carried out in hot benzene, 2-beuzoylthioacctamidophenol ( 4 ) was obtained, which, heated in hot xylene gave 5. Ethyl benzoylacetale by reaction with o-aminothiophenol gave 3 , whereas by reaction with o-aminophenol gave no heterocyclic compound. However, we were able to isolate 2-benzoylacetamidophenol ( 6 ), ethyl β-phenyl-β-(o-hydroxy)phenyliminopropionate ( 7 ), and 2-[β-(o-hydroxy)anilino] cinnamoylamidophenol ( 8 ). Ir and nmr spectra of synthesized compounds point out the existence of tautomers.     

Convenient synthesis of 3-aminomethylenedihydrofuran-2-ones

A simple and convenient synthesis of a series of 3-aminomethylenedihydrofuran-2-ones from the reaction of 3-trichloroacetyl-4,5-dihydrofuran with amines, is presented.     

Features of 2-, 3-Aminopyridines and 2-Aminopyrimidine Condensation with 2-Formylimidazoles

Condensation of 2-, 3-aminopyridines and 2-aminopyrimidine with 1-vinyl- and 1-ethylimidazole-2-carbaldehydes and 1-vinyl-, 1-ethylbenzimidazole-2-carbaldehydes takes two paths depending on the reagents structure: either form Schiff bases or aminals of the corresponding heterocyclic carbaldehydes.     

Parallel synthesis of 3-amino-4H-quinolizin-4-ones, fused 3-amino-4H-pyrimidin-4-ones, and fused 3-amino-2H-pyran-2-ones

On the basis of the enaminone methodology, libraries of 3-amino-4H-quinolizin-4-ones, fused 3-amino-4H-pyrimidin-4-ones, and fused 3-amino-2H-pyran-2-ones were synthesized by the solid-phase and by the solution-phase parallel synthesis. The solution-phase approach turned out to be advantageous over the solid-phase approach. The solution-phase synthesis afforded, in most cases, analytically pure products in high yields, whereas the solid-phase approach gave products in poor yields and in low purity.