Synthesis,structure, and properties of 2-(triphenylstannyloxy)-3,6-di-tert butyl-1,4-benzoquinone

2-(Triphenylstannyloxy)-3,6-di-tert-butyl-1,4-benzoquinone (1) was obtained from the potassium salt of 3,6-di-tert-butyl-2-hydroxy-1,4-benzoquinone and triphenyltin bromide in methanol and characterized by x-ray diffraction analysis, electronic, IR, and NMR spectroscopy. According to x-ray diffraction data, the single crystal of1 has the structure of a chain metal polymer with bridging hydroxy-para-quinone ligands; the coordination number of tin is six. Complex1 is reduced by cobaltocene to the corresponding radical anion. In solutions,1 reacts with metal-centered radicals , and with formation of paramagnetic binuclearortho-semiquinone complexes.Institute of Organometallic Chemistry, Russian Academy of Sciences, 603600 Nizhnii Novgorod. A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2798–2804, December, 1992.     

Study of the reaction of 3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-<Emphasis Type="Italic">о</Emphasis>-benzoquinone with organozinc and organocadmium compounds

The effect of substituents in the reactions of 3,6-di-tert-butyl-о-benzoquinone with organozinc and organocadmium compounds, leading to three types of products: 3-alkyl-6-tert-butyl-о-benzoquinones, 4-alkyl-3,6-di-tert-butyl-о-benzoquinones, and 2-alkoxy-(or 2-phenoxy)-3,6-di-tert-butylphenols. Correlation analysis gave evidence to show that the first- and second-type products are formed by nucleophilic 1,2- and 1,4-addition, while substituted phenols result from single-electron transfer.     

The reaction of 3,6-di-tert-butyl-1,2-benzoquinone and 3,6-di-tert-butylcatechol withtert-butyl hydroperoxide

Reaction of 3,6-di-tert-butyl-1,2-benzoquinone and 3,6-di-tert-butylcatechol withtert-butyl hydroperoxide in aprotic solvents leads to the generation of semiquinone (SQ^.H), alkylperoxy (ROO^.), and alkyloxy radicals. The reaction of SQ^.H and ROO^. produces 2,5-di-tert-butyl-6-hydroxy-1,4-benzoquinone, 3,6-di-tert-butyl-1-oxacyclohepta-3,5-diene-2,7-dione, and 2,5-di-tert-butyl-3,6-dihydroxy-1,4-benzoquinone. The radical generated from solvent attacks SQ^.H at position 4 with C−C bond formation. 4-Benzyl-2,5-di-tert-butyl-6-hydroxycyclohexa-2,5-diene-1-dione produced in this way is transformed into 4-benzyl-3,6-di-tert-butyl-1,2-benzoquinone under the reaction conditions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 943–946, May, 1999.     

Bis(1,4-di-tert-butyl-1,4-diazabutadiene)copper(i) [(3,6-di-tert-butyl-o-benzosemiquinono)(3,6-di-tert-butyl-catecholato)cuprate(ii)]. The molecular structure and intramolecular electron transfer

Bis(1,4-di-tert-butyl-1,4-diazabutadiene)copper(i) [(3,6-di-tert-butyl-o-benzosemiquinono)(3,6-di-tert-butylcatecholato)cuprate(ii)] (1) was synthesized. Complex 1 contains the 1,4-di-tert-butyl-1,4-diazabutadiene and 3,6-di-tert-butyl-o-benzoquinone ligands in the reduced form. The structure of 1 was established by X-ray diffraction analysis. The ESR spectra indicate that dissolution of complex 1 in organic solvents (toluene, THF, CH₂Cl₂, etc.) leads to its symmetrization to give neutral complex 2, which occurs in solutions as an equilibrium mixture of two redox isomers, viz., catecholate (Cat) complex 2c and semiquinone (SQ) complex 2s. In the coordination sphere of the copper atom, the reversible intramolecular metal—ligand electron transfer can proceed as successive steps as exemplified by the reactions of 2 with CO and 2,6-dimethylphenylisonitrile. Copper(i) o-semiquinone complex 2s can be reversibly transformed into copper(ii) catecholate complex 2c through electron transfer from the copper(i) atom to the SQ ligand. The subsequent addition of the neutral ligand (CO or CNAr) to 2c induces, in turn, electron transfer from the Cat ligand to the copper(ii) atom accompanied by the transformation of the catecholate complex into the o-semiquinone complex. In the case of CO, this transformation is also reversible and is efficiently controlled by the temperature.     

New Organotin Compounds Including a Tin–Zinc Bond

Abstract

The reaction of dialkyltinhydrides with dialkylzinc results in a tin metal bond formation. Crystal structures of 1,1,1,2,3,3,3-hepta-phenyl-2-(ethylzincio)tristannane *TMEDA 1, 1,1,2,2,3,3,4,4-octaphenyl-1,4-(ethylzincio)tetrastannane*2TMEDA 2, and triphenyl(phenylzincio)stannane*TMEDA 3 could be obtained.

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GRAPHICAL ABSTRACT     

Antiradical activity of morpholine- and piperazine-functionalized triphenylantimony(V) catecholates

The antiradical activity of the functionalized triphenylantimony(V) catecholates Ph₃Sb[4-O(CH₂CH₂)₂N-3,6-DBCat] (I), Ph₃Sb[4,5-Piperaz-3,6-DBCat] (II), and Ph₃Sb[4-PhN(CH₂CH₂)₂N-3,6-DBCat] (III) (where [4-O(CH₂CH₂)₂N-3,6-DBCat]^2?, [4,5-Piperaz-3,6-DBCat]^2?, and [4-PhN(CH₂CH₂)₂N-3,6-DBCat]^2? are the dianionic ligands 3,6-di-tert-butyl-4-(morpholin-1-yl)-, 3,6-di-tert-butyl-4,5-(piperazine-1,4-diyl)-, and 3,6-di-tert-butyl-4-(4-phenylpiperazin-1-yl)catecholates, respectively) was studied in reactions with the diphenylpicrylhydrazyl radical during autooxidation of unsaturated fatty (oleic and linoleic) acids with lipid peroxidation of Russian sturgeon (Acipenser gueldenstaedti B.) sperm and human blood erythrocytes in vitro as examples. The EC₅₀ and n _DPPH values obtained indicate the high antiradical activity of complexes II and III in the reactions with the stable radical. On the whole, complexes I–III inhibit the lipid peroxidation in both model (oxidation of unsaturated fatty acids) and in vitro experiments. The inhibiting effects of the complexes are comparable with and even, in some cases, higher than those of the known antioxidant ionol.     

Self-association of trimethylsilyl-3,6-di-tert-butyl-o-semiquinone

The reaction of sodium 3,6-di-tert-butyl-o-semiquinolate with Me₃SiCl in THF leads to the formation of 2-(2-trimethylsiloxy-3,6-di-tert-butylphenoxy)-2-trimethylsiloxy-3,6-di-tert-butylcyclohexadien-3,5-one 1. On the basis of IR and UV spectroscopy and analysis of the reaction products, it has been determined that the cyclohexadiene structure 1 is preserved on heating to moderate temperatures or on reaction with water or HCl, but photolysis leads to its decomposition, and so does reaction with metallic sodium or alkali. A scheme of the process is propounded.Institute of Organometallic Chemistry, Russian Academy of Sciences, 603600 Nizhnii Novgorod. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2385–2389, October, 1992.     

Reactions of lithium phenylacetylenide and lithium 3,3-dimethylbut-1-ynide with 3,6-di-tert-butyl-1,2-benzoquinone. Molecular structure of 2,5-di-tert-butyl-8-(3,6-di-tert-butyl-1,2-benzoquinon-4-yl)-8-phenylocta-2,4,6,7-tetraen-1,6-olide

Reactions of 3,6-di-tert-butyl-1,2-benzoquinone with PhC≡CLi and Bu^tC≡CLi are multistage processes. In the first stage, nucleophilic 1,2-addition of the organometallic compound too-benzoquinone occurs to form the corresponding hydroxycyclohexadienone derivative. In polar solvents, the latter undergoes rearrangement through insertion of the oxygen atom into the ring to form a new allenic organolithium compound. The reaction of the newly formed organometallic compound with the initialo-quinone occurs either as a one-electron transfer to yield lithium semiquinolate and a dimerization product,viz., 4,4′-bi(2,5-di-tert-butyl-9,9-dimethyldeca-2,5-dien-7-yn-1,6-olide), or as the 1,4-addition to yield 2,5-di-tert-butyl-8-(3,6-di-tert-butyl-1,2-benzoquinon-4-yl)-8-phenylocta-2,4,6,7-tetraen-1,6-olide. The structure of the latter compound was established by X-ray diffraction analysis and by NMR and IR spectroscopy. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 351–356, February, 1999.     

Interaction of Alkyl Radicals with Dihydric Phenol Derivatives in Hexane Solutions under γ-Radiolysis

The influence of structurally different dihydric phenols on the radical reactions of hexane in deaerated solutions under -irradiation was studied. It was found that 4-tert-butylpyrocatechol (I), 3,5-diisopropylpyrocatechol (II), 2,5-di-tert-butylhydroquinone (III), and 4,6-di-tert-butylresorcinol (IV) effectively inhibited the formation of hexyl radical combination products. Using the chromatography–mass spectrometry technique, it was shown that the adducts of alkyl radicals with I–III have the structure of a monoalkyl ether. Phenol IV gave a mixture of dimers with O- and C-alkylation products.     

Effects of Aminophenol Derivatives on Radiation-Induced Reactions Involving Various Organic Radicals

The effects of some aminophenol derivatives, diphenylamine, and ionol on the formation of ethanol and hexane radiolysis products in aerated and deaerated solutions were studied. The results allowed conclusions to be made about the effect of the structure of test compounds on their reactivity to oxygen- and carbon-centered radicals. It was found that 4,6-di-tert-butyl-2-(N-acetylamino)phenol, 4,6-di-tert-butyl-2-(N-benzoylamino)phenol, 2-hydroxydiphenylamine, and 4-hydroxydiphenylamine were highly competitive with commercial antioxidants in the efficiency of inhibition of radiation-induced processes of hexane oxidation. N-(2-Hydroxy-3,5-di-tert-butylphenyl)aniline, 4,6-di-tert-butyl-2-cyclohexylaminophenol, 2-hydroxydiphenylamine, 4-hydroxydiphenylamine, and N-phenyl-1,4-benzoquinonemonoimine were superior to ionol and diphenylamine in the inhibition of reactions of alkyl and -hydroxyalkyl radicals.     

Synthesis and properties of 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-5-nitroindazole

N-(2-Azido-5-nitrobenzylidene)-3,5-di-tert-butyl-4-hydroxyaniline (3a) and N-(2-azido-5-nitrobenzilidene) aniline (3b), when heated in dimethylformamide yielded 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-5-nitroindazole (4a) and 2-phenyl-5-nitroindazole (4b), respectively. The structure of4b was confirmed by X-ray analysis. A stable phenoxyl radical was shown to originate from the oxidation of4a with lead (IV) dioxide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1095–1097, June, 1994.     

NMR and X-Ray Diffraction Study of Some Inositol Derivatives 1

Abstract

We have determined the preferred conformers in solution by a detailed NMR analysis using COSY and HETCOR experiments of three inositol isomers: myo (1), scyllo (2) and epi (3) plus sixteen derivatives of myo-inositol: 1,2,3,4,5,6-hexa-O-acetyl-myo-inositol (4), 1,2,-O-isopropylidene-myo-inositol (5), 1,2:4,5-di-O-isopropylidene-myo-inositol (6), 3,4,5,6-tetra-O-acetyl-1,2-O-isopropylidene-myo-inositol (7), 3,4,5,6-tetra-O-acetyl-myo-inositol (8), 1,2-O-isopropylidene-3,6-di-O-tosyl-myo-inositol (9), 1,2-O-isopropylidene-3,4,6-tri-O-tosyl-myo-inositol (10), 1,2:4,5-di-O-isopropylidene-3-O-tosyl-myo-inositol (11), 3,6-di-O-benzyl, 1,2:4,5-di-O-isopropylidene-myo-inositol (12), 3,6-di-O-benzyl-1,2-O-isopropylidene-myo-inositol (13), 3,6-di-O-benzyl-myo-inositol (14), 1,2-O-cyclohexylidene-myo-inositol (15), 1,2:4,5-di-O-cyclohexylidene-myo-inositol (16), 1,2:5,6-di-O-cyclohexylidene-myo-inositol (17), 1,3,5-O-(orthoformate)-myo-inositol (18) and 2-benzyl-1,3,5-O-(orthoformate)-myo-inositol (19). The X-ray diffraction structure of compounds 2, 6-8, 18 and 19 are reported.

     

Alkoxylation of 3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-1,2-benzoquinone. New bis-1,2-benzoquinones

Alkoxylation of 3,6-di-tert-butyl-1,2-benzoquinone with a number of diols, including propane-1,3-diol, butane-1,4-diol, di-, and triethylene glycols, and cyclohexane-1,4-diyldimethanol, was studied. Nine new 4-alkoxy-3,6-di-tert-butyl-1,2-benzoquinones were synthesized, four of which were bis-1,2-benzoquinones with different tethers (6–13 atoms) between the quinone fragments. Depending on the length of the chain between the hydroxy groups in glycols, bicyclic 4,5-disubstituted 3,6-di-tert-butyl-1,2-benzoquinones were formed or their stepwise alkoxylation occurred. The newly synthesized o-benzoquinone derivatives can be reduced with alkali metals to give radical anions and converted into semiquinone chelates with manganese carbonyl.     

One-Pot Synthesis and Asymmetric Oxidation of 2-Nitro-4-(Trifluoromethyl)Benzene Containing Sulfides

Abstract

An efficient one-pot method for the preparation of 2-nitro-4-(trifluoromethyl)benzene containing sulfides from 1,1′-disulfanediylbis[2-nitro-4-(trifluoromethyl)benzene] is proposed. The corresponding enantiomerically enriched sulfoxides with up to 78% enantiomeric excess are prepared by the asymmetric oxidation of sulfides using a modified Sharpless method. The yield of sulfoxides is shown to decrease with an increase in the bulk of the aliphatic group and with a decrease of the inductive effect of the hydrocarbonic moiety on the sulfur atom.

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GRAPHICAL ABSTRACT      

Kinetics and mechanism of the reaction of ozone with 3,6-di-tert-butylpyrocatechol

The reaction of ozone with 3,6-di-tert-butylpyrocatechol at 20°C was investigated, and it was found that the main reaction product was 3,6-di-tert-butylquinone, while the reaction rate was proportional to the concentrations of the reagents. A reaction scheme explaining the mechanism of formation of the main and side products is proposed.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1443–1447, June, 1992.     

Investigation on the Ring-Opening Reactions of 3-(1H-1,2,4-Triazol-1-yl)1,5-benzothiazepines with Arylonitrile Oxides

Abstract

Novel ring opening compounds, (Z)-2-((Z)-((E)-1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)allylidene)amino)aryl N-hydroxybenzimidothioates 4a–r, were obtained from the reaction of 2,4-diaryl-3-(1H-1,2,4-triazol-1-yl)-2,5-dihydro-1,5-benzothiazepines 3a–f and arylonitrile oxides. The structure of these products has been elucidated by spectroscopic analysis and, in one case, X-ray crystallographic analysis. According to the result, it was presumed that this reaction did not proceeded through 1,3-dipolar cycloaddition reaction.

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GRAPHICAL ABSTRACT      

Functionalized derivatives of sterically hinderedo-quinones and pyrocatechols. 3,6-di-tert-butyl-4-dicyanometyl-1,2-benzoquinone and its isomers

Base-catalyzed interaction of 3,6-di-tert-butyl-1,2-benzoquinone with malononitrile mainly occurs as 1,4-addition to give 3,6-di-tert-butyl-4-dicyanomethylpyrocatechol. Its oxidation leads to 3,6-di-tert-butyl-4-dicyanomethyl-1,2-benzoquinone, which converts into 3,6-di-tert-butyl-2-hydroxy-α,α-dicyano-1,4-quinomethane in solution and in the solid state. The latter rearranges into isomeric 3,6-di-tert-butyl-5-dicyanomethylenecyclohex-3-ene-1,2-dione. Reverse conversion occurs under the action of amines. Semiquinone complexes of dicyanomethylquinone were studied in solutions by ESR.     

Synthesis of New 1-Naphthol Aza Oxa Thia Crowns

Abstract

New dinaphthosulfide aza oxa thia crowns from 1-naphthol were prepared. At first, 2,2′-thiobis(1-hydroxynaphthalene) (a dinaphthol) was prepared from 1-naphthol. Then diester was prepared from the reaction of dinaphthol and methylchloroacetate. Aza crowns were synthesized from the reaction of diester and diamines (ethylene diamine, 1,3-diaminopropane, 1,4-diaminobutane, and 1,6-diaminohexane) in methanol.

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GRAPHICAL ABSTRACT      

Regioselective Syntheses of 1-Aryl-substituted-5H-[1,3]thiazolo[3,2-a]quinazoline-5-ones During Sonogashira Coupling

Abstract

Reaction of 2-mercaptopropargylquinazoline-4-one with various aryliodides catalyzed by Pd–Cu leads to the regioselective formation of 1-arylsubstituted-5H-[1,3]thiazolo-[3,2-a]quinazoline-5-ones.

GRAPHICAL ABSTRACT