Reaction of sterically hindered bromocyclohexadienones with 2,4,6-tri-tert-butylphenol

Conclusions The EPR method was used to study the kinetics of the reaction of quinone bromide compounds, containing functional substituents, with 2,4,6-tri-tert-butylphenol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 859–861, April, 1971.     

Synthesis of liquid crystalline materials based on 1,3,5-triphenylbenzene and 2,4,6-triphenyl-1,3,5-s-triazine

C₃-symmetric alkyloxy/aryloxy polyether dendrimers have been synthesized from 1,3,5-triphenylbenzene and 2,4,6-triphenyl-1,3,5-s-triazine and their liquid crystalline properties have been studied. C₃-symmetric derivatives with n-hexyl and n-dodecyl chains at the periphery show mesophase properties when they are complexed with trinitrofluorenone at different temperatures.     

Thermodynamic study of 1,2,3-triphenylbenzene and 1,3,5-triphenylbenzene

The energetic study of 1,2,3-triphenylbenzene (1,2,3-TPhB) and 1,3,5-triphenylbenzene (1,3,5-TPhB) isomers was carried out by making use of the mini-bomb combustion calorimetry and Knudsen mass-loss effusion techniques. The mini-bomb combustion calorimetry technique was used to derive the standard (p° = 0.1 MPa) molar enthalpies of formation in the crystalline state from the measured standard molar energies of combustion for both isomers. The Knudsen mass-loss effusion technique was used to measure the dependence with the temperature of the vapour pressure of crystalline 1,2,3-TPhB, which allowed the derivation of the standard molar enthalpy of sublimation, by application of the Clausius–Clapeyron equation. The sublimation study of 1,3,5-TPhB had been performed previously. From the combination of data obtained by both techniques, the standard molar enthalpies of formation in the gaseous state, for both isomers, at T = 298.15 K, were calculated. The results indicate a higher stability of the 1,3,5-TPhB isomer relative to 1,2,3-TPhB, similarly to the terphenyls. Nevertheless, the 1,2,3-TPhB isomer is not as energetically destabilized as one might expect, supporting the existence of a π–π displacive stacking interaction between both pairs of outer phenyl rings. The volatility difference between the two isomers is ruled by the enthalpy of sublimation. The volatility of the 1,2,3-TPhB is two orders of magnitude higher than the 1,3,5-TPhB isomer, at T = 298.15 K.     

4.

Self-addition of a sterically hindered alkynylselenolate     

Pietschnig R  Schäfer S  Merz K 《Organic letters》2003,5(11):1867-1869

[structure: see text] The unprecedented formation of a complex macrocyclic selenium-carbon ring system, which is initiated by the action of coordinating reagents upon a sterically hindered alkynylselenolate, has been observed. The crystal structure of the product could be obtained and shows a rigid tricyclic arrangement consisting only of selenium and sp(2)-hybridized carbon atoms. This reactivity stands in contrast to the corresponding unsubstituted alkynylselenolates and is an example where a bulky substituent destabilizes an adjacent unsaturated pi-system.     

5.

1,3,5-三乙酰基六氢均三嗪的小分子法合成反应机理研究   总被引：1，自引：0，他引：1  

娄忠良  王鹏  孟子晖  刘越  覃光明  葛忠学  王伯周 《有机化学》2010,30(7)

1,3,5-三乙酰基六氢均三嗪(1,3,5-triacetyl-1,3,5-triazacyclohexane,TRAT)是高性能单质炸药黑索金的关键硝化前体.本研究以小分子三聚甲醛和乙腈为原料,浓硫酸为催化剂,合成了TRAT,产率为89%.合成并表征了N,N'-亚甲基二乙酰胺和未见报道的三乙酰基二亚甲基三胺.根据已得到的几个中间体,推测了TRAT合成反应的可能机理.     

6.

Reaction of 4-nitro-2,4,6-tri-tert-butyl-2,5-cyclohexadienone with sterically hindered phenols and diphenylpicrylhydrazine     

A. I. Prokof'ev  S. P. Solodovnikov  A. A. Volod'kin  V. V. Ershov 《Russian Chemical Bulletin》1971,20(6):1239-1241

Conclusions The EPR method was used to study the reaction of 4-nitro-4-methyl-2,6-di-tert-butyl-2,5-cyclohexadienone with some sterically hindered phenols and diphenylpicrylhydrazine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1333–1335, June, 1971.The authors express their gratitude to S. L. Soshk for assistance in the work when taking the oxidation polarograms.     

7.

Reaction of salts of sterically hindered phenols with 4-bromo-2,4,6-tri-tert-butyl-2,5-cyclohexadienone     

S. G. Kukes  N. N. Bubnov  A. I. Prokof'ev  S. P. Solodovnikov  A. A. Volod'kin  G. A. Nikiforov  V. V. Ershov 《Russian Chemical Bulletin》1973,22(1):191-192

     

8.

Reaction of sterically hindered cyclohexadienones with 2,4,6-tri-tert-butylphenol and 2,2′,6,6′-tetra-tert-butylindophenol     

Prokof'ev  A. I.  Solodovnikov  S. P.  Volod'kin  A. A.  Ershov  V. V. 《Russian Chemical Bulletin》1971,20(2):352-354

Conclusions 1. The EPR method was used to study the kinetics of the reaction of 4-bromo-2,4,6-tri-tert-butyl-2,5-cyclohexadienone, 4-chloro-2,4,6-tri-tert-butyl-2,5-cyclohexadienone and 4-nitro-2,4,6-tri-tert-butyl-2,5-cyclohexadienone with 2,4,6-tri-tert-butylphenol and 2,2,6,6-tetra-tert-butylindophenol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 419–421, February, 1971.     

9.

Radical-anions of sterically hindered alkylbenzophenones     

A. I. Samokhvalova  O. G. Sokol  V. M. Kazakova 《Journal of Structural Chemistry》1978,18(5):764-766

     

10.

1,3,5-2,4,6-functionalized,facially segregated benzenes-exploitation of sterically predisposed systems in supramolecular chemistry     

Hennrich G  Anslyn EV 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(10):2218-2224

In the present article, we introduce the unique steric features of 1,3,5-substituted triethylbenzenes as a design principle for host molecules and supramolecular systems. Due to steric gearing, all three functional substituents are disposed on the same side of the phenyl plane. The use of this benzene scaffold has lead to the synthesis of various receptor molecules for a wide range of different guest species. Furthermore, the facially segregated systems can be used as building blocks with a controlled conformation in the synthesis of macrocycles or self-assembled supramolecular systems.     

11.

High-pressure transesterification of sterically hindered esters     

Jan Romanski  Piotr NowakKrzysztof Kosinski  Janusz Jurczak 《Tetrahedron letters》2012,53(39):5287-5289

A mild, rapid, and efficient method for the solvolysis of sterically hindered esters under high pressure is described. Transesterification is carried out in the presence of DBU at room temperature and at a pressure of 10 kbar to give quantitative conversions within short reaction times. The substrates examined included aromatic and aliphatic esters of sterically hindered alcohols and phenols. An optically pure benzyl ester of phenylalanine was chosen to study racemization of the amino acid esters under high-pressure reaction conditions.     

12.

Aquametric microdetermination of sterically hindered ketones     

F. B. Sherman  Ch'ang Man Pin  V. A. Klimova 《Russian Chemical Bulletin》1972,21(4):895-897

Conclusions The previously developed aquametric micromethod for determining carbonyl compounds also gives reliable results when most of the sterically hindered ketones studied by us are analyzed. The determination error is ±0.3%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 942–944, April, 1972.     

13.

Photoisomerization of sterically hindered polymethine dyes     

A. P. Darmanyan  V. A. Kuz'min  L. M. Panova  M. A. Al'perovich  I. I. Levkoev 《Russian Chemical Bulletin》1977,26(8):1790-1794

Conclusions In sterically hindered polymethine dyes the photoisomerization process, with the formation of sterically hindered trans and di-cis forms, successfully competes with the nonradiative degradation of the energy on the higher vibrational sublevels of the ground state.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1926–1930, August, 1977.     

14.

Claisen rearrangement of sterically hindered N-alkenylindolines     

I. B. Abdrakhmanov  A. G. Mustafin  G. A. Tolstikov  L. V. Spirikhin  L. M. Khalikov 《Russian Chemical Bulletin》1987,36(3):561-565

Conclusions Claisen rearrangement of N-(1-methyl-2-butenyl)-2-methyl-2-ethylindoline occurs under mild conditions upon treatment with acids at 20°C. Tricyclic compounds, namely, 6,6-dimethylperhydroeyclopent[g]-2-methyl-2-ethylindoline and 8-methyl-8-ethylpyrrolidino[h, i]-3-methyl-2-ethylindole, were obtained from 7-(1-methyl-2-butenyl)-2-methyl-2-ethylindoline.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 613–618, March, 1987.     

15.

Conformation of sterically hindered 4-nitropiperidines     

L. A. Myshkina 《Russian Chemical Bulletin》1983,32(4):752-755

     

16.

Mass spectra of sterically hindered phenols     

A. V. Krokhin  O. S. Chizhov  N. N. Mikheeva  V. V. Ershov  A. A. Volod'kin 《Russian Chemical Bulletin》1975,24(10):2219-2221

     

17.

Synthesis of sterically hindered aromatic aldehydes     

A. P. Yakubov  D. V. Tsyganov  L. I. Belen'kii  M. M. Krayushkin 《Russian Chemical Bulletin》1991,40(7):1427-1432

Formylation of mesitylene, durene, and m-xylene derivatives containing electron-donor and electron-acceptor substituents by dichloromethyl methyl ether was studied in the presence of TiCl₄. A series of functionally substituted sterically hindered benzaldehydes was prepared from the products of these reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1609–1615, July, 1991.     

18.

Synthesis of sterically hindered aromatic dialdehydes     

A. P. Yakubov  D. V. Tsyganov  L. I. Belen'kii  M. M. Krayushkin 《Russian Chemical Bulletin》1991,40(7):1509-1512

A study was carried out on the formylation of a series of aromatic compounds containing two mesitylene or durene residues [dimesityl (I), dimesitylmethane (II), 1,2-dimesitylethane (III), 1,6-dimesitylhexane (IV), dimesityl sulfide (V), 1,1-dimesitylethylene (VI), 1,1-dimesityl-1-butene (VII), and didurylmethane (VIII)] by the action of dichloromethyl methyl ether (DCM) in the presence of A1C1₃ and TiCl₄. The corresponding dialdehydes are the major products. The formylation products when the reaction is carried out in the presence of A1C1₃ in the case of (I) and (V) contain significant amounts of monoaldehydes, while partial cleavage of the substrates with the formation of products containing only one benzene ring is observed in the case of (II) and (VIII) in addition to formylation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1700–1703, July, 1991.     

19.

Dipole moments of sterically hindered p-hydroxystyrylpyridines     

N. R. Kal'nitskii  A. K. Sheinkman  A. N. Rozenberg  G. N. Bogdanov 《Chemistry of Heterocyclic Compounds》1973,9(11):1383-1386

On the basis of measurements of dipole moments and a comparison of the results obtained with those calculated by a vectorial additive scheme, the structure of a series of sterically hindered p-hydroxystyrylpyridines have been determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1528–1531, November, 1973.     

20.

Synthesis of sterically hindered benzoquinone methacrylates     

M. P. Shurygina  O. V. Markina  N. O. Druzhkov  T. I. Kulikova  A. V. Cherkasov  A. V. Piskunov  S. A. Chesnokov  V. K. Cherkasov 《Russian Chemical Bulletin》2012,61(6):1215-1219

Sterically hindered p- and o-benzoquinone methacrylates, viz., 2,5-di(tert-butyl)-3,6-di-oxocyclohexa-1,4-dienyl methacrylate and 2,5-di(tert-butyl)-3,4-dioxocyclohexa-1,5-dienyl methacrylate, were synthesized by O-acylation of the lithium and tetrabutylammonium salts of 3,6-di(tert-butyl)-2-hydroxy-p-benzoquinone with methacryloyl chloride. The influence of the nature of cation and solvent on regioselectivity of the acylation was studied. The o-benzoquinone derivative obtained can serve as a paramagnetic ligand in metal complexes.     

Self-addition of a sterically hindered alkynylselenolate

[structure: see text] The unprecedented formation of a complex macrocyclic selenium-carbon ring system, which is initiated by the action of coordinating reagents upon a sterically hindered alkynylselenolate, has been observed. The crystal structure of the product could be obtained and shows a rigid tricyclic arrangement consisting only of selenium and sp(2)-hybridized carbon atoms. This reactivity stands in contrast to the corresponding unsubstituted alkynylselenolates and is an example where a bulky substituent destabilizes an adjacent unsaturated pi-system.     

1,3,5-三乙酰基六氢均三嗪的小分子法合成反应机理研究

1,3,5-三乙酰基六氢均三嗪(1,3,5-triacetyl-1,3,5-triazacyclohexane,TRAT)是高性能单质炸药黑索金的关键硝化前体.本研究以小分子三聚甲醛和乙腈为原料,浓硫酸为催化剂,合成了TRAT,产率为89%.合成并表征了N,N'-亚甲基二乙酰胺和未见报道的三乙酰基二亚甲基三胺.根据已得到的几个中间体,推测了TRAT合成反应的可能机理.     

Reaction of 4-nitro-2,4,6-tri-tert-butyl-2,5-cyclohexadienone with sterically hindered phenols and diphenylpicrylhydrazine

Conclusions The EPR method was used to study the reaction of 4-nitro-4-methyl-2,6-di-tert-butyl-2,5-cyclohexadienone with some sterically hindered phenols and diphenylpicrylhydrazine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1333–1335, June, 1971.The authors express their gratitude to S. L. Soshk for assistance in the work when taking the oxidation polarograms.     

Reaction of sterically hindered cyclohexadienones with 2,4,6-tri-tert-butylphenol and 2,2′,6,6′-tetra-tert-butylindophenol

Conclusions 1. The EPR method was used to study the kinetics of the reaction of 4-bromo-2,4,6-tri-tert-butyl-2,5-cyclohexadienone, 4-chloro-2,4,6-tri-tert-butyl-2,5-cyclohexadienone and 4-nitro-2,4,6-tri-tert-butyl-2,5-cyclohexadienone with 2,4,6-tri-tert-butylphenol and 2,2,6,6-tetra-tert-butylindophenol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 419–421, February, 1971.     

1,3,5-2,4,6-functionalized,facially segregated benzenes-exploitation of sterically predisposed systems in supramolecular chemistry

In the present article, we introduce the unique steric features of 1,3,5-substituted triethylbenzenes as a design principle for host molecules and supramolecular systems. Due to steric gearing, all three functional substituents are disposed on the same side of the phenyl plane. The use of this benzene scaffold has lead to the synthesis of various receptor molecules for a wide range of different guest species. Furthermore, the facially segregated systems can be used as building blocks with a controlled conformation in the synthesis of macrocycles or self-assembled supramolecular systems.     

High-pressure transesterification of sterically hindered esters

A mild, rapid, and efficient method for the solvolysis of sterically hindered esters under high pressure is described. Transesterification is carried out in the presence of DBU at room temperature and at a pressure of 10 kbar to give quantitative conversions within short reaction times. The substrates examined included aromatic and aliphatic esters of sterically hindered alcohols and phenols. An optically pure benzyl ester of phenylalanine was chosen to study racemization of the amino acid esters under high-pressure reaction conditions.     

Aquametric microdetermination of sterically hindered ketones

Conclusions The previously developed aquametric micromethod for determining carbonyl compounds also gives reliable results when most of the sterically hindered ketones studied by us are analyzed. The determination error is ±0.3%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 942–944, April, 1972.     

Photoisomerization of sterically hindered polymethine dyes

Conclusions In sterically hindered polymethine dyes the photoisomerization process, with the formation of sterically hindered trans and di-cis forms, successfully competes with the nonradiative degradation of the energy on the higher vibrational sublevels of the ground state.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1926–1930, August, 1977.     

Claisen rearrangement of sterically hindered N-alkenylindolines

Conclusions Claisen rearrangement of N-(1-methyl-2-butenyl)-2-methyl-2-ethylindoline occurs under mild conditions upon treatment with acids at 20°C. Tricyclic compounds, namely, 6,6-dimethylperhydroeyclopent[g]-2-methyl-2-ethylindoline and 8-methyl-8-ethylpyrrolidino[h, i]-3-methyl-2-ethylindole, were obtained from 7-(1-methyl-2-butenyl)-2-methyl-2-ethylindoline.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 613–618, March, 1987.     

Synthesis of sterically hindered aromatic aldehydes

Formylation of mesitylene, durene, and m-xylene derivatives containing electron-donor and electron-acceptor substituents by dichloromethyl methyl ether was studied in the presence of TiCl₄. A series of functionally substituted sterically hindered benzaldehydes was prepared from the products of these reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1609–1615, July, 1991.     

Synthesis of sterically hindered aromatic dialdehydes

A study was carried out on the formylation of a series of aromatic compounds containing two mesitylene or durene residues [dimesityl (I), dimesitylmethane (II), 1,2-dimesitylethane (III), 1,6-dimesitylhexane (IV), dimesityl sulfide (V), 1,1-dimesitylethylene (VI), 1,1-dimesityl-1-butene (VII), and didurylmethane (VIII)] by the action of dichloromethyl methyl ether (DCM) in the presence of A1C1₃ and TiCl₄. The corresponding dialdehydes are the major products. The formylation products when the reaction is carried out in the presence of A1C1₃ in the case of (I) and (V) contain significant amounts of monoaldehydes, while partial cleavage of the substrates with the formation of products containing only one benzene ring is observed in the case of (II) and (VIII) in addition to formylation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1700–1703, July, 1991.     

Dipole moments of sterically hindered p-hydroxystyrylpyridines

On the basis of measurements of dipole moments and a comparison of the results obtained with those calculated by a vectorial additive scheme, the structure of a series of sterically hindered p-hydroxystyrylpyridines have been determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1528–1531, November, 1973.     

Synthesis of sterically hindered benzoquinone methacrylates

Sterically hindered p- and o-benzoquinone methacrylates, viz., 2,5-di(tert-butyl)-3,6-di-oxocyclohexa-1,4-dienyl methacrylate and 2,5-di(tert-butyl)-3,4-dioxocyclohexa-1,5-dienyl methacrylate, were synthesized by O-acylation of the lithium and tetrabutylammonium salts of 3,6-di(tert-butyl)-2-hydroxy-p-benzoquinone with methacryloyl chloride. The influence of the nature of cation and solvent on regioselectivity of the acylation was studied. The o-benzoquinone derivative obtained can serve as a paramagnetic ligand in metal complexes.