Synthesis and Structure of Diisopropyl 6-Hydroxy-6-methyl-4-oxocyclohexane-1,3-dicarboxylates and Their Reactions with Nucleophilic Reagents

Base-catalyzed reactions of isopropyl acetoacetate with aromatic and heterocyclic aldehydes afforded the corresponding diisopropyl 6-hydroxy-6-methyl-4-oxocyclohexane-1,3-dicarboxylates which were brought into reactions with mono- and difunctional nitrogen-containing nucleophiles. According to the X-ray diffraction data, diisopropyl 4-oxocyclohexane-1,3-dicarboxylates in crystal exist in the ketone form.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 1039–1045.Original Russian Text Copyright © 2005 by Gein, Nosova, Potemkin, Aliev, Kriven’ko.     

Reaction of dialkyl 2-aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxylates with aliphatic amines

Benzylamine, phenethylamine, and homoveratrylamine reacted with dialkyl 2-aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxylates at the endocyclic carbonyl group with conservation of the enolic hydroxy group to give dialkyl 4-alkylamino-2-aryl-6-hydroxy-6-methylcyclohex-3-ene-1,3-dicarboxylates. The reaction of dimethyl 4-hydroxy-4-methyl-6-oxo-2-phenylcyclohexane-1,3-dicarboxylate with tryptamine was accompanied by dehydration with formation of dimethyl 4-[2-(1H-indol-3-yl)ethylamino]-6-methyl-2-phenylcyclohexa-3,5-diene-1,3-dicarboxylate, presumably due to basic properties of the indole nitrogen atom.     

Liquid-phase oxidation of sulfides by an aluminum (and titanium) <Emphasis Type="Italic">tert</Emphasis>-butoxide—<Emphasis Type="Italic">tert</Emphasis>-butyl hydroperoxide system

A system aluminum (and titanium) tert-butoxide—tert-butyl hydroperoxide (1 : 2) under mild conditions (20 °C, 1 h) oxidizes aliphatic and alkylaromatic sulfides and diphenyl sulfide to the corresponding sulfones in yields close to 100%. The oxidation is induced by electron-excited dioxygen formed upon thermal decomposition of intermediate metal-containing peroxy trioxides (ozonides). The latter are formed as a result of the reversible reaction of aluminum or titanium tert-butoxides with tert-butyl hydroperoxide followed by the interaction of di-tert-butoxy-tert-butylperoxyaluminum and tri-tert-butoxy-tert-butylperoxytitanium that formed with another Bu^tOOH molecule. Aluminum-containing peroxide (Bu^tO)₂AlOOBu^t oxidizes sulfides to sulfoxides.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1663–1668, August, 2004.     

A free-radical reaction of alkanoic acids with tetrachloroethylene

The di-tert-butyl peroxide-initiated free-radical reaction of C₃-C₆ alkanoic acids with tetrachloroethylene results in the formation of a mixture of isomeric (trichlorovinyl)alkanoic acids with the predominant isomer bearing the trichlorovinyl group at the (–1) position.Translated fromIzveshya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1011–1013, April, 1996.     

Synthesis of Derivatives of of Δ2-Imidazolin-5-one and Imidazolidine Containing Residues of Sterically-hindered Phenols

1-Substituted 4-benzylidene-2-{-[3,5-di(tert-butyl)-4-hydroxyphenyl]vinyl}-4-benzylidene-²-imidazolin-5-ones have been synthesized by the interaction of azomethines and N-acylhydrazones (derivatives of 3,5-di(tert-butyl)-4-hydroxybenzaldehyde) with 4-benzylidene-2-methyloxazol-5-one. The acylation of 1,2-bis[3,5-di(tert-butyl)-4-hydroxybenzylideneamino]ethane with acid chlorides in acetonitrile in the presence of triethylamine leads to 1,3-diacyl-2-[3,5-di(tert-butyl)-4-hydroxyphenyl]imidazolidine.     

1,3-Bis[tert-butyl(di-tert-butylfluorsilyl)amino]trisulfan – eine Verbindung mit FSiNSSSNSiF-Helix

1,3-Bis[tert-butyl(di-tert-butylfluorosilyl)amino]trisulfane – a Compound with FSiNSSSNSiF Helix The lithium derivative of tert-butyl(di-tert-butylfluorosilyl)-amine ( 1 ) reacts with sulfur or selenium to give the bis[(fluorosilyl)-amino]di- and -trisulfanes 2, 3 and -selane 4 , respectively. The trisulfane 3 crystallizes from n-hexane and exhibits a helical structure (X-ray analysis).     

A New Synthetic Method for the Preparation of N,N-Dimethylformamide DI-Tert-Butyl Acetal

A new synthetic method for the preparation of N,N-dimethylformamide di-tert-butyl acetal by acid catalyzed transacetalization of readily available N,N-dimethylformamide dimethyl acetal is described.     

Complexation of copper(II) with β-<Emphasis Type="Italic">tert</Emphasis>-butyl L-aspartate in the presence of anionic surfactant

Complexation of copper(II) with -tert-butyl L-aspartate in aqueous solutions of the anionic surfactant, sodium dodecyl sulfate, was studied by spectrophotometry, followed by mathematical processing of the results. Compositions of complexes and equilibrium constants of their formation reactions were determined.Translated from Kolloidnyi Zhurnal, Vol. 66, No. 6, 2004, pp. 860–861.Original Russian Text Copyright © 2004 by Vladimirova, Vladimirov.     

Chemoselective acylation of monosubstituted thiacalix[4]arene with di-<Emphasis Type="Italic">tert</Emphasis>-butyl dicarbonate

Mono-, di-, and tetrasubstituted derivatives of p-tert-butylthiacalix[4]arene containing tert-butylcarbamate, tert-butylcarbonate, and tert-butyl fragments have been prepared for the first time. Depending on the reaction conditions (reagents ratio, temperature, and the presence of a base), the interaction of the monoamine derivative of p-tert-butylthiacalix[4]arene with di-tert-butyl dicarbonate can lead to the formation of mono-, di-, and tetrasubstituted products.     

Homolytic and Conjugate Addition of Thiols to 2,4-Dimethyl-2-vinyl-1,3-dioxa-2-silacyclohexane

Homolytic reaction of 1-propane- and 1-pentanethiols to 2,4-dimethyl-2-vinyl-1,3-dioxa-2-silacyclohexane, initiated by di-tert-butyl peroxide at 130°C, yields a mixture of isomeric sulfides (95%) as a result of addition at the - and -positions of the vinyl group. Conjugate addition of alkanethiols in the presence of the corresponding sodium thiolate at 100°C gives 10% of the same - and -regioisomeric sulfides at a ratio of 1:20.     

Synthesis and molecular structure of 7<Emphasis Type="Italic">H</Emphasis>-12-oxa-3,7-diazapleiadene-substituted 1,3-tropolones

An acid-catalyzed reaction of substituted 2-methyl-7H-12-oxa-3,7-diazapleiadenes with 1,2-benzoquinones leads to 7H-12-oxa-3,7-diazapleiadene-substituted 1,3-tropolones. Molecular structure of 5,7-di(tert-butyl)-2-[9,11-di(tert-butyl)-4-methyl-7H-12-oxa-3,7-diazapleiaden-2-yl]-4-nitro-1,3-tropolone was established by X-ray crystallography. Energy and structural characteristics of isomeric 5,7-di(tert-butyl)-2-[9,11-di(tert-butyl)-4-methyl-7H-12-oxa-3,7-diazapleiaden-2-yl]-4-nitro-1,3-tropolones in the gaseous phase and a polar solution were studied by the PBE0/6-31G** method.     

Reaction of aromatic aldehydes with β-dicarbonyl compounds in a catalytic system: Piperidinium acetate-1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

Condensation of aromatic (heteroaromatic) aldehydes with 1,3-dicarbonyl compounds under the 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF₄]) ionic liquid-piperidinium acetate catalytic system (0.2 equiv. of each component) in the absence of a solvent affords, depending on the structures of the reagents, 2-arylidene derivatives of methyl acetoacetate and acetylacetone, diethyl 2,4-bis(trifluoroacetyl)-3-phenylpentanedioate, or dimethyl 2-aryl-4-hydroxy-6-oxocyclohexane-1,3-dicarboxylates. The reactions of the resulting 2-arylidene derivatives with O-methylisourea in the [Bmim][BF₄] ionic liquid produced methyl 2-methoxy-4-methyl-6-aryldihydropyrimidine-5-carboxylates and 1-(2-methoxy-4-methyl-6-phenyldihydropyrimidin-5-yl)ethanone (mixtures of 3,6- and 1,6-dihydro isomers), which were transformed into the corresponding 3,4-dihydropyrimidin-2(1H)-one derivatives. 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. 1199–1204, May, 2005.     

Reaction Between 5-Isopropylidene-2,2-dimethyl-1,3-dioxane-4,6-dione and <Emphasis Type="Italic">tert</Emphasis>-Butyl Isocyanide in the Presence of Primary or Secondary Amines

Summary. 5-Isopropylidene-2,2-dimethyl-1,3-dioxane-4,6-dione (the condensation product of Meldrums acid and acetone) reacts smoothly with tert-butyl isocyanide in the presence of primary or secondary amines to produce N-tert-butyl-2,2-dimethylbutyramide derivatives and/or 1-tert-butyl-4,4-dimethyl-2,5-dioxopyrrolidine-3-carboxamides in good yields.     

Crystal and molecular structure of the (1 : 1) clathrate between a calix[4]arene containing onep-nitrophenol unit and toluene

p-(Methyl,tert-butyl, nitro,tert-butyl) calix[4]arene: toluene, C₃₇H₄₁NO₆. C₇H₈,M _r = 687.87, triclinic, ,a = 13.668(2),b = 12.187(2),c = 13.231(1) Å, = 106.78(8), = 77.88(1), = 114.00(1)°,V = 1916.8(8) ų,Z = 2,D _x = 1.19 g cm^–3, (CuK ) = 1.54178 Å, = 5.90 cm^–1,F(000) = 736,T = 293 K, finalR = 0.068 for 6309 observed reflections. This macrocycle, having different substituents at the positionspara to the hydroxyl groups, is the first one of its type to be studied. The general conformation of this calix[4]arene is compared to similar symmetrical ones. Thetert-butyl groups are not disordered as is usual and toluene is retained between the macrocycles. Two calixarene molecules are positioned to permit atert-butyl group of one to be inside the cavity of the second to establish CH₃- interactions.     

Rate constants for the reactions of OH radicals and Cl atoms with diethyl sulfide,Di-n-propyl sulfide,and Di-n-butyl sulfide

Rate constants for the reactions of OH radicals and Cl atoms with diethyl sulfide (DES), di-n-propyl sulfide (DPS), and di-n-butyl sulfide (DBS) have been determined at 295 ± 3 K and a total pressure of 1 atm. Hydroxyl radical rate data was obtained using the absolute technique of pulse radiolysis combined with kinetic spectroscopy. The chlorine atom rate constants were measured using a conventional photolytic relative rate method. The rate constant for the reaction of Cl atoms with dimethyl sulfide (DMS) was also determined. The following rate constants were obtained:      

Carbon-carbon bond formation by radical addition of α-trifluoromethylacrylate with cyclic ethers

The radical addition reactivity of tert-butyl α-trifluoromethylacrylate (CH₂C(CF₃)COOC(CH₃)₃) (BFMA) with cyclic ethers was investigated in order to compare to that of perfluoroisopropenyl ester. One to one addition compound of BFMA with tetrahydrofuran (THF) was produced in fairy high yields in the presence of 2,2′-azobisisobutyronitrile, benzoyl peroxide or di-tert-butyl peroxide to give 2-substituted THF derivative. Time-conversion investigation showed much higher reactivity of BFMA compared to that of 2-benzoxypentafluoropropene [CF₂C(CF₃)OCOC₆H₅]. Radical additions of BFMA with 1,4-dioxane, 1,3-dioxolane and tetrahydropyran were also examined to afford corresponding 1:1 addition products in fairly high yields by achieving carbon-carbon bond formation. It is then concluded that no interconversion of fluoroalkylcarbon radical and hydrocarbon radical may take place in the reaction system of BFMA which possesses two less fluorines in the vinyl group compared to 2-benzoxypentafluoropropene. The method may be a facile way to prepare trifluoromethyl-substituted organic compounds accompanied by the formation of carbon-carbon bonds by the aid of fluorine atoms.     

Reactions of 3а,6a-diaza-1,4-diphosphapentalene with activated acetylenes

The reaction of cyclohexane-annulated 3 a,6a-diaza-1,4-diphosphapentalene (DDP) with di-tert-butyl acetylenedicarboxylate (DBAD) affords the 1,3-dipolar cycloaddition product of the acetylene moiety to the phosphorus and sp²-carbon atoms of DDP in 90% yield. No individual products were isolated in the reaction of DDP with dimethyl acetylenedicarboxylate (DMAD). In the three-component DDP–DMAD–carbazole system (1: 2: 1), a product was generated in 73% yield via successive reactions, including the 1(P),3(C)-dipolar cycloaddition of DMAD to DDP, the addition of the second equivalent of DMAD to the three-coordinate phosphorus atom of the intermediate, and the NH addition of carbazole at the unsaturated C=C bond of the second DMAD moiety. The structures of the reaction products were established by X-ray diffraction.     

Synthesis and Biological Activity of Some Trifluoromethyl Derivatives of 5-tert-Butyl-2-furylmethylideneanilines and Their Silyl Analogs

We have synthesized the corresponding aldimines by condensation of 5-tert-butylfurfural and its trimethyl- and triethylsilyl analogs with 2-, 3-, and 4-trifluoromethylanilines in the presence of 4 molecular sieves. We have studied their neurotropic and antitumor activity. The phenamine motor activity test showed that tert-butyl derivatives exhibit high efficacy and also shorten the ethanol narcosis time. Some silyl derivatives exhibit significant anti-corazole activity. The tert-butyl derivatives have high cytotoxicity toward human lung fibrosarcoma cells (the 3-trifluoromethyl-substituted derivative) and mouse hepatoma cells (the 2-trifluoromethyl-substituted derivative).     

Spectres RMN et analyse conformationnelle de germa-4 dioxannes-1,3

Methods for the calculation of the torsional angle of the C? C linkage

1 Voir Réf. 1.

are applied to some 4-germa-1,3-dioxanes. It is thereby shown that 4,4-diethyl-2trichloromethyl-4-germa-1,3-dioxane in CCl ₄ and C ₆ D ₆ adopts the chair conformation, with the equatorial C? Cl ₃ group distorted by the presence of the germanium: the torsional angle of the Ge-CH ₂ -CH ₂ -O-fragment is 45°. The most stable 6-alkyl derivatives ( cis isomers) have the same conformation; the less stable trans - tert -butyl isomer prefers a skew-boat form compatible with a torsional angle of about 60°.     

Reaction Between Alkyl Isocyanides and Cyclic 1,3-Diketones: A Convenient Synthesis of Functionalized 4 H-Pyrans

Alkyl isocyanides react with dialkyl acetylendicarboxylates in the presence of CH-acids such as cyclopentane-1,3-dione, cyclohexane-1,3-dione, or 5,5-dimethylcyclohexane-1,3-dione to afford highly functionalized 4H-pyrans in fairly high yields. In the case of reaction between dimethyl acetylenedicarboxylate and 5,5-dimethylcyclohexane-1,3-dione in the presence of cyclohexyl isocyanide or benzyl isocyanide tetrahydro-cyclopenta[b]pyran derivatives were isolated in addition to the 4H-pyran system. The free energy barrier (96.9kJmol^–1) for restricted rotation around the polarized double bond of the enaminone moiety in dimethyl 2-[cyclohexylamino-(4,4-dimethyl-2,6-dioxocyclohexylidene)methyl]but-2-enedioate was determined by dynamic NMR spectroscopy.