A new route for the synthesis of 1,3-diketones

A simple route for the synthesis of 1,3-diketones by the reaction of acetylenic ketones with amines followed by hydrolysis of the resulting aminovinylketons is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 710–714, April, 1995.     

Electrochemical oxidation of 1,3-diketones in the presence of hydrohalic acid salts

In the presence of a mediator (sodium iodide) acetylacetone dimerizes with the formation of 3,4-diacetylhexane-2,5-dione, with a yield up to 90%. Salts of 2-halosubstituted 1,3-diketones form more highly enolized cyclic 1,3-diketones — 1,3-cyclohexanedione and dimedone under analogous conditions, with a yield up to 90%.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 154–158, January, 1992.     

Reversal of diastereoselectivity in palladium-arene interaction directed hydrogenative desymmetrization of 1,3-diketones

For the metal-catalyzed asymmetric hydrogenation of α-substituted ketones,cis reductive products are generally obtained due to steric hindrance of substituents.Herein,an unprecedented trans reductive products were observed in palladium-catalyzed hydrogenative desymmetrization of cyclic and acyclic 1,3-diketones,providing the chiral trans β-hydroxy ketones with two adjacent stereocenters including one α-tertiary or quaternary stereocenter with high enantioselectivity and diastereoselectivity.Mechanistic studies and DFT calculations suggested that the rarely observed diastereoselectivity reversal is ascribed to the charge-charge interaction between the palladium and aromatic ring of the substrate,which could not only result in the reversal of the diastereoselectivity,but also improve the reactivity.     

Sterically hindered 1,3-diketones in the Michael reaction

The base catalyzed addition of sterically hindered 1,3-diketones to the activated multiple bond of ethyl acrylate and 4-methyl-4-methoxy-1-phenylpent-2-yne-1-one has been studied. The addition of methyl(2-propenyl)ketone is partially accompanied by intramolecular cyclization of the resulting adduct.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 147–149, January, 1996.     

Aminomethylation of hindered 2-propargyl-1,3-diketones

2-Propargyl-substituted methoxy-1,3-diketones react with alkoxymethylamines or paraform and secondary amines in the presence of CuCl at the acetylene group to afford Mannich bases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1293–1295, May, 1996.     

Acylation of sterically hindered 2-propargyl-1,3-diketones

Sterically hindered 2-propargyl-1,3-diketones were acylated at the terminal acetylenic group by acyl chlorides in the presence of CuCl. Some peculiarities of the reaction were revealed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 199–201, January, 1999.     

Synthesis of 3-arylazo-1H-pyridazin-4-ones from difluoroboron chelates of 1,3-diketones

A convenient method for the synthesis of 6-R-3-arylazo-1H-pyridazin-4-ones from difluoroboron chelates of acetylacetone and aroylacetones was developed. The method is based on the ability of the methyl group of the chelates to react with two equivalents of a diazonium salt. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1502–1506, August, 2007.     

Novel,Recyclable, and Thermally Stable Task-Specific Ionic Liquid (TBA Acetate) Medium/Catalyst for the Synthesis of Indolylidinecyclic-1,3- and -1,4-diketones

A simple and efficient synthesis of indolylidinethiazolidnediones (3) and indolylidinecyclic-1,3-diketones (5) has been developed by reaction of indole-3-aldehyde (1) with thiazolidinedione (2) or cyclic-1,3-diketones (4) using tetra butyl ammonium acetate (TBAA) melt as novel, cost-effective, and recyclable ionic liquid under solvent-free green conditions at 100 °C for 15–20 min without additional use of catalyst.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Interaction of fluorine-containing 1,3-dicarbonyl compounds with polyamines

In the reaction of fluorinated copper(II) 1,3-diketonates with diethylenetriamine (or triethylenetetramine) in CHCl₃, N,N-bis(1,3-aminovinylketones) are formed in 21–35% yields. Fluorine-containing 1,3-diketones and 1,3-ketoesters, upon interaction with polyamines without solvent, undergo acid cleavage, forming the corresponding amides. The copper(II) 1,3-ketoesterates are readily cleaved in CHCl₃ at 25°C in excess triethylenetetramine or ethylenediamine.Department of Fine Organic Synthesis, Institute of Organic Chemistry, Ural Branch, Russian Academy of Sciences, 620219 Ekaterinburg. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2591–2596, November, 1992.     

Template reactions of fluorine-containing 1,3-diketones with ethylenediamine

Depending on the nature of the dicarbonyl fragment, the reaction of fluorinated copper(II) bis(1,3-diketonates) with ethylenediamine and its monoprotonated salts under mild conditions gives N,N-ethylenebis(aminovinyl ketones) and/or 1,4-diazepines. In excess ethylenediamine, copper(II) and nickel(II) N,N-ethylenebis(aminovinyl ketonates) undergo cyclization to 1,4-diazepines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2088–2092, September, 1991.     

Synthesis of monoprotected 1,4-diketones by photoinduced alkylation of enones with 2-substituted-1,3-dioxolanes

Photosensitized hydrogen abstraction from 2-alkyl-1,3-dioxolanes by triplet benzophenone gives the corresponding 1,3-dioxolan-2-yl radicals and these are trapped by ,β-unsatured ketones yielding monoprotected 1,4-diketones. With open chain ketones (3-buten-2-one and 4-penten-3-one) the yields are low and competitive pathways in part consume the radicals. With cyclic enones however, yields are good as tested with cyclopentenone, cyclohexenone and 4-hydroxy-cyclopentenone. More generally, this is a viable alternative for the synthesis of 1,4-diketones via radicals while the thermal initiation gives only low yield. The reaction cannot be extended to strongly stabilized radicals, such as the 2-phenyl-1,3-dioxolanyl radical.     

Rh(III)-catalyzed C-H activation of primary benzamides and tandem cyclization with cyclic 2-diazo-1,3-diketones for the synthesis of isocoumarins

A simple and efficient Rh(III)-catalyzed C-H activation and tandem intramolecular cyclization for the synthesis of isocoumarins has been developed. The protocol uses easily available primary benzamides and cyclic 2-diazo-1,3-diketones as starting materials. This reaction proceeds via C-C and C-O bond formation in a single reaction vessel, and the corresponding isocoumarins were obtained in moderate to excellent yields (58%–97%). The well established protocol showed high functional group tolerance, which provided an efficient and alternative route to isocoumarin backbone.     

New access to 1,3-diketones from aldehydes

A simple and efficient methodology to introduce an 1,3-diketone motif from various aldehyde precursors in three steps with good overall yields is described using β-ketosulphone 7 as masked equivalent of acetone.     

A four-step tandem synthesis of 3,5-diaroyl-4-arylpyrazoles from 1,3-diaryl-propane-1,3-diketones

A novel four-step tandem procedure was developed for efficient synthesis of 3,5-diaroyl-4-arylpyrazoles by simply stirring the mixture of 1,3-diarylpropane-1,3-diketones, TsN₃, aqueous MeNH₂ and Na₂CO₃ in DMF at 85 °C for 3 h.     

Copper-catalyzed methylation of 1,3-diketones with tert-butyl peroxybenzoate

Copper-catalyzed radical methylation of 1,3-diketones with tert-butyl peroxybenzoate in air is described, providing a general pathway to α-methyl 1,3-diketones in moderate to good yields. This protocol has been scaled up to 50 g, and one of the synthesized products can be used in the synthesis of medicine, Rosuvastatin.     

Synthesis and antiangiogenic activities of 5-amino-1,3-dihydro-1, 3-dioxo-2H-isoindole-2-propanoic acid derivatives

Based on the structure-activity relationships and antiangiogenic mechanism of RGD-containing peptides,a series of 5-amino- 1,3-dihydro-1,3-dioxo-2H-isoindole derivatives were synthesized.The structures were characterized by ~1H NMR,MS and elementary analysis.There ability to inhibit angiogenesis were evaluated by chick embryo chorioallantoic membrane assay at 10~(-5) mol/L.Compounds 7a and 7b displayed obvious antiangiogenic activity.     

Unexpected synthesis of 1,3,5-triarly-1,5-diketones from aryl ketones via di-enamine mechanism

An unexpected reaction of aryl ketone with acetohydrazone of aromatic aldehyde via 1,2-di-enamine/di-iminium mechanism was discovered, leading to efficient synthesis of 1,3,5-triaryl-1,5-diketones in good to excellent yields.     

Condensation of 1,3-diketones with 1,8-diaminonaphthalene: Synthesis ofbis(2,3-dihydroperimidine-2-spiro)cycloalkanes

Summary Cyclic 1,3-diketones like cyclopentane-1,3-dione, cyclohexane-1,3-dione, and 5,5-dimethylcyclohexane-1,3-dione react with 1,8-diaminonaphthalene to afford new condensed heterocyclic spiro systems.

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Kondensation von 1,3-Diketonen mit 1,8-Diaminonaphthalin: Synthese vonBis(2,3-dihydroperimidin-2-spiro)cycloalkanen

Zusammenfassung Cyclische 1,3-Diketone wie Cyclopentan-1,3-dion, Cyclohexan-1,3-dion und 5,5-Dimethylcyclohexan-1,3-dion reagieren mit 1,8-Diaminonaphthalin zu neuen kondensierten heterocyclischen Spiranen.

     

Synthesis of 2′-hydrazine oligonucleotides and their efficient conjugation with aldehydes and 1,3-diketones

Oligodeoxyribonucleotides that contain a novel nucleoside, 2′-O-(2-hydrazinoethyl)uridine, were synthesised by NaBH₃CN reduction of hydrazones formed from 2′-O-(2-oxoethyl)oligonucleotides with FmocNHNH₂, followed by concd aq NH₃ deprotection. The 2′-hydrazine oligonucleotides obtained were then used to synthesise a number of conjugates with aldehydes via hydrazone formation and with1,3-diketones via pyrazole formation. The method was shown to be applicable for the preparation of oligonucleotide-peptide conjugates.     

Regioselective synthesis of fluorine-containing indazolones from 2-acylcyclohexane-1,3-diones

New regioisomeric indazolones containing fluorine atoms in the aromatic ring have been synthesized in high yield by the interaction of 2-acylcyclohexane-1,3-diones, and of their enol methyl ethers, obtained by methylating the initial β,β′-triketones with dimethyl sulfate in the presence of calcined potassium carbonate, with 4-fluorophenylhydrazine hydrochloride and with pentafluorophenylhydrazine. The structures of the synthesized compounds were confirmed by data of IR and ¹H, ¹³C, and ¹⁹F NMR spectra. Dedicated to Distinguished Scientist Academician A. A. Akhrem in his 95^th Year. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 393–403, March, 2008.