2,3-Di-tert-butyl-1-telluradiphosphiran und verwandte Phosphor—Tellur-Heterocyclen

2,3-Di-tert-butyl-1-telluradiphosphirane and related Phosphorus—Tellurium Heterocycles 2,3-Di-tert-butyl-1-telluradiphosphirane was isolated in pure state by trap to trap condensation after reaction of 1,2-Di-tert-butyl-1,2-dichlorodiphosphane with sodium telluride in pentane suspension. The telluradiphosphirane and other P? Te heterocycles (t-BuP)_nTe_m (n = 2, m = 1; n = 3, m = 1,2; n = 4, m = 1,2) are formed from 1,2-Di-tert-butyl-1,2-dichlorodiphosphane or tert-butyldichlorophosphane with bis(trimethylsilyl)telluride and from the reaction of tert-butylbis(trimethylsilyl)phosphane with elemental tellurium. The proposed structures of the P? Te heterocycles are based on ³¹P- and ¹²⁵Te-n.m.r. and MS data     

Reactions of [(3,5-Di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-oxocyclohexa-2,5-dien- 1-ylidene)methyl]phosphonates with Phenols

Dialkyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonates reacted with phenol and benzenediols in the presence of trifluoromethanesulfonic acid to give products of electrophilic substitution in the benzene ring, the corresponding diarylmethylphosphonates or [phenylenebis(arylmethylene)]- diphosphonates. The reaction of diphenyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonate with 2-methylbenzene-1,3-diol at a ratio of 1: 1 afforded 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-6-hydroxy-7-methyl-2-phenoxy-2,3-dihydro-1,2λ⁵-benzoxaphosphol-6-one.     

Synthesis of aromatic tetracyclic tin compounds by template and transmetallation reactions: Alkyl vs aryl migration from tin to nitrogen

The syntheses of [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]diphenyltin (1) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]dichloro-phenyl-stannate (2) by template reactions using 3,5-di-tert-butylcatechol, aqueous ammonia and SnPh₂Cl₂ are reported. We also report the syntheses of compounds 2, [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]trichloro-stannate (4), [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)methylamine]chloro-methyltin (5), and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)-n-butylamine]n-butyl-chlorotin (6) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]n-butyl-dichloro-stannate (7), performed by transmetallation reactions of the octahedral zinc coordination compound Zn[3,5-di-tert-butyl-1,2-quinone-(3,5-di-tert-butyl-2-hydroxy-1-phenyl)imine]₂ (3) with SnPhCl₃ or SnPh₂Cl₂, SnCl₄, SnMe₂Cl₂, Sn(nBu)₂Cl₂ and Sn(nBu)Cl₃, respectively. The X-ray diffraction structures of compounds 1, 2, 4 and 6 are reported. The transmetallation reactions with Sn(alkyl)₂Cl₂ afforded pentacoordinated tin compounds, where an alkyl group migrated from tin to nitrogen, while similar reactions with Sn-Ph compounds did not present any phenyl group migration.     

Synthesis of new ordered aromatic polyester copolymers

Aromatic polyesters of 3,5-di-tert-butyl-4-hydroxybenzoic acid and 3,5-diisopropyl-4-hydroxybenzoic acid were prepared. The polymers were found to be high-melting but largely insoluble in organic solvents. The polymer based on 3,5-di-tert-butyl-4-hydroxy-benzoic acid was not degraded to monomer by sulfuric acid. A number of new aromatic polyesters were also prepared. Several new monomers for aromatic polyesters were synthesized, including bis(2,5-di-tert-butyl-4-carbophenoxyphenyl)terephthalate, m- and p-phenylene bis(3,5-di-tert-butyl-4-hydroxybenzoate), bis(2,6-di-tert-butyl-4-chlorocarboxyphenyl)terephthalate, and m-phenylene bis(3,5-diisopropyl-4-hydroxybenzoate). An aromatic polyester prepared from bis(2,6-di-tert-butyl-4-chlorocarboxyphenyl) terephthalate and resorcinol had a η_inh (trichloroethylene) of 1.05 (0.5%, 30°C) and a possible melting point of 330°C (DSC). Tough, creasable films could be cast from trichloroethylene solution of this polymer. Attempts to observe or to trap the keto-ketene that might result when 3,5-di-tert-butyl-4-hydroxybenzoyl chloride is treated with base were unsuccessful.     

Synthesis and Chemical Transformations of β-(3,5-DI-tert-butyl-4-hydroxyphenyl)propionic Hydrazide

A method for synthesis of -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic hydrazide. Certain chemical properties of the product were studied. It was found that -(3,5-di-tert-butyl-4-hydroxyphenyl) -(3,5-di-tert-butyl-4-hydroxyphenyl)hydrazide is highly susceptible to oxidation.     

Reactions of 3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-1,2-benzoquinone with mercapto carboxylic acids

Heating of an equimolar mixture of 3,5-di-tert-butyl-1,2-benzoquinone with thiosalicylic acid led to 2-[(4,6-di-tert-butyl-2,3-dihydroxyphenyl)thio]benzoic acid. In the case of β-mercaptopropionic acid, 2-[(4,6-di-tert-butyl-2,3-dihydroxyphenyl)thio]propionic acid was formed, which upon reflux in Ac2O was converted to 6,8-di-tert-butyl-9-hydroxy-3,4-dihydro-2H-1,5benzoxathiepin-2-one.     

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.     

Reaction of a stable silylene with tetrahydrofuran

Reduction of 1,3-di-tert-butyl-2,2-dichloro-2,3-dihydro-1H-1,3,2-diazasilole with metallic potassium gave, instead of a stable silylene, 1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2λ²-diazasilylolene, a product of insertion of the latter into the carbon-oxygen bond of tetrahydrofuran, 1,4-di-tert-butyl-6-oxa-1,4-diaza-5-silaspiro[4,5]dec-2-ene.     

Antiradical activity of benzazole-2-thiones

Reaction of benzoxazole-2-thione with 3,5-di-tert-butyl-4-hydroxybenzylacetate in methanol affords S-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-mercaptobenzoxazole as the major product. Antiradical activity of S- and N-3,5-di-tert-butyl-4-hydroxybenzyl derivatives of benzothiazole(oxazole, imidazole)-2-thione with respect to 2,2-diphenyl-1-picrylhydrazyl is varies widely. S-Benzyl derivatives exhibit higher reactivity at 30°C.     

Reaction of <Emphasis Type="Italic">o</Emphasis>-Quinones in Cyclohexane Solutions with Alkyl Radicals Generated by Solution γ-Irradiation

The structures of products formed in reactions of tert-butylated o-quinones with alkyl radicals were determined by ¹H and ¹³C NMR and two-dimensional ¹H-¹H NOESY spectroscopy, and also by gas chromatography-mass spectrometry. The major products formed upon γ-irradiation of deaerated solutions of 4-tert-butyl-1,2-benzoquinone and 3,5-di-tert-butyl-1,2-benzoquinone in cyclohexane are monoalkyl ethers and products of addition to the C=C bond. In the case of 4-tert-butyl-1,2-benzoquinone, these are products of mixed O-C and C-C alkylation; the adduct formed by addition of the cyclohexyl radical to the C=C bond in 3,5-di-tert-butyl-1,2-benzoquinone gives an unsymmetrical dimer whose structure was proved by single-crystal X-ray diffraction.     

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.     

Monoetherification of tert-Butylated Pyrocatechols upon Irradiation of Their Solutions in Hydrocarbons

Products of reactions of tert-butylated pyrocatechols with alkyl radicals were studied. The major products formed upon -irradiation of deaerated solutions of 4-tert-butyl- and 3,5-di-tert-butylpyrocatechol in hexane and cyclohexane are monoalkyl ethers, which were identified by NMR spectroscopy (¹H, ¹³C, ¹H-¹H NOESY technique) and gas chromatography-mass spectrometry.     

Hypervalent and binuclear silicon and germanium derivatives from bis-(3,5-di-tert-butyl-2-phenol)-oxamide

The reactions of bis-(3,5-di-tert-butyl-2-phenol)oxamide (1) with Cl₂SiR₂ (Me or Ph) or Cl₂GeR₂ (Me, nBu or Ph) in THF provided binuclear pentacoordinated silicon and germanium compounds: bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-dimethylsilane (2), bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-diphenylsilane (3), bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-dimethylgermane (4), bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-di-n-butylgermane (5) and bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-diphenylgermane (6). The mono-nuclear tetracoordinated silicon compounds N-acetyl-bis-(3,5-di-tert-butyl-2-oxo-phenyl)-amide-bis-(dimethylsilane) (8) and N-acetyl-bis-(3,5-di-tert-butyl-2-oxo-phenyl)-amide-bis-(diphenylsilane) (9) were synthesized from N-(3,5-di-tert-butyl-2-phenol)acetamide (7) and Cl₂SiR₂ (R = Me and Ph). Comparison of the ²⁹Si NMR chemical shifts of the penta- (2 and 3) and tetracoordinated (8 and 9) silicon compounds provided information about the intramolecular coordination of the carbonyl group to the silicon atom. Compounds 3 and 6 were characterized by single-crystal X-ray analyses. They have planar hexacyclic structures where the central atoms present distorted tbp geometries with one nitrogen and two carbon atoms in equatorial positions and two oxygen atoms in apical positions.     

Chlorination of 3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-1,2-benzoquinone in two-phase catalytic system

Chlorination of 3,6-di-tert-butyl-1,2-benzoquinone in a two-phase catalytic system (CH₂Cl₂, HCl- H₂O, H₂O₂, Bu₄NCl) led to halogen addition at the C=C bond, and subsequent dehydrochlorination of the adduct gave 3,6-di-tert-butyl-4-chloro-1,2-benzoquinone. Chlorination of the latter afforded 3,6-di-tert-butyl-4,5-dichloro-1,2-benzoquinone.     

Dissociation energies of O–H bonds in alkylseleno- and alkyltelluro-substituted phenols

The O?H bond dissociation energy (D _O?H) has been determined for eight alkylseleno-substituted phenols, one alkyltelluro-substituted phenol, and one alkyltelluro-substituted pyridinol. D _O?H has been estimated by the intersecting-parabolas method from kinetic data using five reference compounds: α-tocopherol (D _O?H = 330.0 kJ/mol), 3,5-di-tert-butyl-4-methoxyphenol (D _O?H = 347.6 kJ/mol), 4-methylphenol (D _O?H = 361.6 kJ/mol), 2,6-di-tert-butyl-4-methylthiophenol (D _O?H = 336.3 kJ/mol), and 2,6-di-ter-tbutyl-4-methylphenol (D _O?H = 338.0 kJ/mol). The following D _O?H values (kJ/mol) have been obtained: 335.9 for 2,5,7,8-tetramethyl-2-phytyl-6-hydroxy-3,4-dihydro-2H-1-benzoselenopyran, 342.6 for 2-methyl-5-hydroxy-2,3-dihydrobenzoselenophene, 333.5 for 2,4,6,7-tetramethyl-5-hydroxy-2,3-dihydrobenzoselenophene, 339.4 for 2-tert-butyl-4-methoxy-6-octylselenophenol, 357.9 for dodecyl 3-(4-hydroxyphenyl) propyl selenide, 348.5 for dodecyl 3-(3,5-dimethyl-4-hydroxyphenyl)propyl selenide, 350.9 for dodecyl 3-(3-tert-butyl-4-hydroxyphenyl)propyl selenide, 338.0 for dodecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propyl selenide, 343.0 for 2,6-di-tert-butyl-4-(tellurobutyl-4′-phenoxy)phenol, and 338.8 for 6-octyltelluro-3-pyridinol. The stabilization energies of phenoxyl radicals containing R substituents (X = O, S, Se, Te) have been compared.     

Anionic condensations of 3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4(2)-hydroxybenzaldehydes in the presence of weak bases

Products of the reactions of 4- and 2-hydroxy-3,5-di-tert-butyl-benzaldehydes with malonic acid, diethyl malonate, and acetic anhydride in the presence of weak bases were isolated and identified. The reactions of 3,5-di-tert-butyl-4-hydroxybenzaldehyde with malonic acid and acetic anhydride in the presence of sodium acetate and piperidine gave 3,5-di-tert-butyl-4-hydroxycinnamic acid. The reaction of its 2-hydroxy isomer with acetic anhydride stopped at the stage of formation of the corresponding O-acetyl derivative, while in the reaction with malonic acid the corresponding substituted cinnamic acid and its lactone (coumarin derivative) were formed as intermediate products in a transformation sequence finally leading to 3-(3,5-di-tertbutyl-2-hydroxyphenyl)-3-piperidinopropionic acid and 6,8-di-tert-butyl-2-oxo-3,4-dihydro-2H-chromen-4-ylacetic acid. Analogous differences were typical of reactions of isomeric 4- and 2-hydroxy-3,5-di-tert-butylbenzaldehydes with diethyl malonate. The transformations of the 2-hydroxy isomer were accompanied by hydrolysis and formation of an adduct of intermediate coumarin derivative with diethyl malonate and piperidine.     

Two-dimensional correlation NMR study of the structure of by-product in the reaction of 2-methylquinoline with 3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-1,2-benzoquinone

The reaction of 2-methylquinoline with 3,5-di-tert-butyl-1,2-benzoquinone afforded a mixture of 5,7-di-tert-butyl-3-hydroxy-2-(quinolin-2-yl)cyclohepta-2,4,6-trien-1-one and previously unknown 10-tert-butylindolo[1,2-a]quinoline-8,11-dione. The structure of the latter was determined by two-dimensional heteronuclear correlation NMR spectroscopy.     

Synthesis,structure and antioxidant activity of sulfur-containing tetrakisphenol

3-[2-(3,5-Di-tert-butyl-4-hydroxyphenylsulfanyl)acetoxy]2,2-bis[2-(3,5-di-tert-butyl-4-hydroxyphenylsulfanyl) acetoxymethyl]propyl 3,5-di-tert-butyl-4-hydroxyphenylsulfanylacetate was synthesized. Its structure was determined by means of ¹H and ¹³C NMR spectroscopy and X-ray-diffraction analysis. This compound was found to possess high antioxidant activity in the conditions of auto-oxidation of low-pressure polyethylene.     

Reactions of Arylenedioxytrihalophosphoranes with Acetylenes: XV.<Superscript>1</Superscript> Reaction of 2,2,2-Tribromo-4,6-di-<Emphasis Type="Italic">tert</Emphasis>-butylbenzo-1,3,2λ<Superscript>5</Superscript>-dioxaphospholedioxaphosphole with Pent-1-yne

2,2,2-Tribromo-4,6-di-tert-butylbenzo-1,3,2λ⁵-dioxaphospholedioxaphosphole reacted with a terminal alkyne, pent-1-yne, to give a mixture of two isomeric 1,2-benzoxaphosphinine derivatives, 6,8- and 5,7-di-tert-butyl-2-bromo-4-propylbenzo-1,2λ⁵-oxaphosphinin-2-oxides, at a ratio of 5.9: 1. The regioselectivity of substitution of oxygen in the dioxaphosphole fragment by carbon differs from that observed previously in the reaction with 4,6-di-tert-butyl-2,2,2-trichlorobenzo-1,3,2λ⁵-dioxaphosphole: the minor isomer was formed as a result of substitution of the oxygen atom in the ortho position with respect to one tert-butyl group of the initial phosphole.     

Features of photolytic transformations of di-<Emphasis Type="Italic">o</Emphasis>-quinones containing sulfide fragments

Quantum yields and products of photolytic transformation of bis(2,5-di-tert-butylcyclohexadiene-1,5-dion-3,4-yl)sulfide and 1,4,7,10-tetra-tert-butyl-5,6,11,12-tetrathia-dibenzo-cyclooctene-2,3,8,9-tetraone dissolved in saturated hydrocarbon at the action of irradiation with wavelength 436 and 313 nm, respectively. Possible mechanism of these photo reactions is proposed.