Synthesis of 1-Aryl-1,3-Diketones Containing the Dimethyl Malonate Moiety

The synthesis of new 1,3-diketones malonates 3 a-j were prepared in good yield from 1,5-diketones 2 a-j by employing the 1,5 → 1,3 diketone rearrangement.     

Reaction of 3,5-diamino-4-nitropyrazole with electrophilic reagents

The interaction of 3,5-diamino-4-nitropyrazole with such electrophilic reagents as acetic anhydride, dimethylformamide acetal, orthoformic ester, and ketones has been studied. Derivatives of pyrazolol[1,5-a]pyrimidines were formed on reaction with 1,3-diketones and some of their properties have been studied.Center for Drug Chemistry, All-Russian Chemical and Pharmaceutical Research Institute (VNIKhFI), Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 329–335, March, 1997.     

Reaction of 1-amino-, 2-amino-, and 1,2-diaminoimidazoles with β-diketones

1,2-Diamino-4-phenylimidazolium perchlorate condenses with 2 mole of β-diketones to give pyrimido[2′,1′:2,3]imidazo[1,5-b]pyridazinium derivatives, while, like 1-amino-2-mercapto-4-phenylimidazole, to give imidazo[1,5-b]pyridazine derivatives. Salts of 1-benzylideneamino- and 1-(2-thiazolyl)-2-aminoimidazoles react with β-diketones to give substituted imidazo[1,2-a]pyrimidinium derivatives.     

Synthesis of 4H-pyrans by O-cyclization of 1,5-diketones

Substituted 4H-pyrans were obtained in high preparative yields by the reaction of 1,5-diketones with acetic anhydride and boron trifluoride etherate in diethyl ether. It is assumed that the heterocyclization of 1,5-diketones includes a step involving the formation and transformations of an acyloxy carbonium ion.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 320–322, March, 1992.     

Chemistry of 1,5-diketones: I. Halogenation of aryl-substituted pent-2-ene-1,5-diones,pentane-1,5-diones,and their fused analogs

Halogenation of 3-(4-methoxyphenyl)-1,5-diphenylpent-2-ene-1,5-dione, 3-(4-methoxyphenyl)-1,5-diphenylpentane-1,5-dione, and 2-[1-(4-methoxyphenyl)-3-oxo-3-phenylpropyl)-1,2,3,4-tetrahydroaphthalen-one with bromine, chlorine, and dichloro(phenyl)-λ³-iodane leads to formation of the corresponding monobromo-, dichloro-, or trichloro-substituted 1,5-diketones, depending on the conditions. Halogenation of the aliphatic chain and methoxyphenyl substituent can be accompanied by heterocyclization to give pyrylium salts.     

trans-Stereoselective intramolecular crossed pinacol coupling of aromatic 1,4-, 1,5-, and 1,6-diketones by electroreduction

Electroreduction of aromatic 1,4-, 1,5-, and 1,6-diketones in the presence of chlorotrimethylsilane and triethylamine gave four-, five-, and six-membered 1,2-diols with trans-stereoselectivity.     

Reactions of 1,5-diketones

Two-ring 1,5-diketones of the benzylidenedicyclohexanone type are capable of existing in equilibrium with 4a-hydroxy-1,2,3,4,4a,5,6,7,8,9a-decahydroxanthenes, the position of which depends on the structure of the 1,5-diketone.     

Synthesis and stereochemistry of 2-arylperhydrocyclopenta[b]pyridin-1-ols, 8-azaestrone fragments

Different stereoisomers of 2-arylperhydrocyclopenta[b]pyridin-1-ols, which form structural motifs of 8-azaestrone, were prepared via reductive cyclization from mono-oximes derived from 1,5-diketones, by using sodium borohydride and acetic acid in THF at reflux.     

Synthesis of benzylidenecycloalkan-1-ones and 1,5-diketones under Claisen–Schmidt reaction: Influence of the temperature and electronic nature of arylaldehydes

Herein, we present the results of the influence of reaction temperature and the electronic nature of arylaldehydes in the reactions of benzocycloalkan-1-ones and arylaldehydes under classical Claisen–Schmidt condensation conditions. The products obtained, 2-arylidene derivatives of benzocycloalkan-1-ones and/or spiropolycyclic-1,5-diketones through multicomponent reactions, depended on the electronic nature of arylaldehyde and the reaction temperature. Besides, under identical conditions, 2-arylideneindan-1-ones afforded bis-indane-1,5-diketones through a process that involves Michael addition reaction, which is also dependent on the temperature. Theoretical studies using density-functional theory allowed understanding the chemical reactivity and the site selectivity of α,β-enones used in this work through the calculation of global and local electrophilicity on C–β. Both the electrophilicity of C-β and the temperature led the course of reaction toward the formation of aldol condensation, aldol condensation/Michael addition, and aldol condensation/dimerization products. This work is the first to perform the structural and configurational assignments of bis-indane-1,5-diketones.     

Halogenation of 1,5-Diketones

Published and experimental data of authors on halogenation of 1,5-diketones from acyclic (among them chalcogen-containing), semicyclic and bicyclic series resulting in formation of mono-, di-, tri-, and tertahalosubstituted 1,5-dioxo compounds, pyrylium halides, and their fused analogs or aroylfurans are reviewed.     

Lewis Acid Mediated Addition of Aminoketene Dithioacetals to α, β-Unsaturated Ketones

Lewis acids catalyse the addition of aminoketene dithioacetals to α-β-unsaturated ketones to give 1,5-diketones after hydrolytic work-up.     

A facile one-pot highly chemo- and regioselective synthesis of the novel heterocyclic system indolo[1,2-c]azolo[1,5-a]quinazoline-8,10-dione

A series of novel indolo[1,2-c]azolo[1,5-a]quinazoline-8,10-diones was obtained by a multi-component reaction between cyclic 1,3-diketones, α-aminoazoles, and glyoxal. The unexpected cyclization process was established by NMR spectroscopy and X-ray diffraction measurements.     

New Tetracyclic Spiro-1,2,4-trioxolanes (Ozonides). Synthesis and Mass Spectrometric Study

Russian Journal of Organic Chemistry - New tetracyclic dispiro-1,2,4-trioxolanes (ozonides) were synthesized by reactions of 5–7-membered alicyclic 1,5-diketones with 30% hydrogen peroxide in...     

Xanthene Derivatives and <Emphasis Type="Italic">ortho</Emphasis>-Substituted Phenols — Products from Dehydrogenation of Acyclic 1,5-Diketones

Xanthene derivatives and ortho-substituted phenols were obtained during the dehydrogenation of 1,5-diketones and their ketol forms at a Pt/C catalyst at 280–320°C. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1637–1643, November, 2005.     

Unsaturated 1,5-diketones and their halogen-substituted derivatives — Preparation and use in the synthesis of heterocycles

Published data and the results of the authors' own research on methods for the production of unsaturated 1,5-diketones and halogen-substituted 2-pentene-1,5-diones and their use in the synthesis of difficulty obtainable pyrylium, 3,5-dichloropyrylium, and 3-chlorothiopyrylium salts, aroylfurans, 40-chloroaroylfurans, isoxazolines, pyrazolines, 3,5-dichloropyridines, 1,4-tetramethylenebispyridines, and others are summarized. Aspects of the structure of 2-pentene-1,5-diones and their 2,4-dichloro-substituted analogs and features of their heterocyclization are discussed in comparison with pentane-1,5-diones and their 2,4-dichloro-substituted derivatives.N. G. Chernyshevskii Saratov State University, Saratov, K. A. Fedin Saratov State Pedagogical Institute, Saratov. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1319, October, 1996. Original article submmited June 8, 1995     

Modified reaction conditions to achieve high regioselectivity in the two component synthesis of 1,5-diarylpyrazoles

The factors affecting regioselectivity during the formation of 1,5-diarylpyrazoles from aryl hydrazines and 1,3-diketones are identified and the regioisomers were characterized by 1D NOESY, LC-NMR and X-ray analyses. A simple alteration in the usual reaction conditions is reported, which allows the exclusive formation of 1,5-diarylpyrazoles.     

Heterocyclization of 1,5-diketones by catalytic reduction (review)

Literature reports and the writers' own work on the synthesis of saturated six-membered oxygen heterocycles by catalytic reduction of 1,5-diketones are reviewed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1011–1018, August, 1990.     

Reactions of 1,5-diketones with 2-aminobenzyl alcohol and 2-aminomethylaniline and behavior of the products in oxidative coupling

Reactions of some 1,5-diketones with 2-aminobenzyl alcohol and 2-aminomethylaniline follow double cyclization scheme with formation of pyridobenzoxazine and pyridoquinazoline derivatives, respectively. Oxidative coupling of the cyclization products with CH acids occurs at the 4-position of the pyridine ring.     

Regioselective hydration of alkynones by palladium catalysis

Diketones are regioselectively prepared from alkynyl ketones under mild conditions by palladium catalysis; 5-heptyn-2-one and 2-(2-nonynyl)cyclohexanone give 1,4-dikektones whereas 2-(2-heptynyl)cyclopentanone and 5,6-didehydroprostaglandin E₂ methyl ester afford 1,5-diketones.     

Thiapyrylium and pyrylium salts with furyl substituents

The possibility of obtaining pyrylium and thipyrylium salts that contain acidophobic furyl substituents by the action of protic acids on the corresponding 1,5-diketones in acetic acid or methanol, depending on the position of the furan rings relative to the carbonyl groups, was established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1604–1607, December, 1981.