Octane Compounds Research Articles

How far the substituent effects in disubstituted cyclohexa-1,3-diene derivatives differ from those in bicyclo[2.2.2]octane and benzene?

Substituents effects in cyclic diene derivatives are studied using quantum chemical modeling and compared to the corresponding effects in aromatic (benzene) and fully saturated (bicyclo[2.2.2]octane) compounds. In particular, electronic properties of the fixed group Y in a series of 3- and 4-X-substituted cyclohexa-1,3-diene-Y derivatives (where Y = NO2, COOH, COO− OH, O−, NH2, and X = NMe2, NH2, OH, OMe, Me, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, NO2, NO) are examined using the B3LYP/6-311++G(d,p) method. For this purpose, quantum chemistry models of the substituent effect: cSAR (charge of the substituent active region) and SESE (substituent effect stabilization energy) as well as traditional Hammett’s substituent constants (σ) and their inductive (F) and resonance (R) components are used. π-electron delocalization of the transmitting moiety (butadiene fragment of the CHD) is described by the HOMA index. This comparative study reveals interplay between inductive and resonance contributions to the substituent effect.

Synthesis, Antifungal Activity, and Biocompatibility of Novel 1,4-Diazabicyclo[2.2.2]Octane (DABCO) Compounds and DABCO-Containing Denture Base Resins.

The fungal pathogen Candida albicans causes a variety of oral infections, including denture stomatitis, which is characterized by inflammation of the oral mucosa in direct contact with dentures and affects a significant number of otherwise healthy denture wearers. While antifungal treatment reduces symptoms, infections are often recurrent. One strategy to address this problem is to incorporate compounds with fungicidal activities into denture materials to prevent colonization. Our laboratory synthesized novel derivatives of 1,4-diazabicyclo[2.2.2]octane (DABCO), which is an organic compound typically used as a catalyst in polymerization reactions. DABCO derivatives with different aliphatic chain lengths (DC16, DC16F, DC18, and C6DC16), as well as methacrylate monomers conjugated to DABCO compounds (DC11MAF and C2DC11MAF), were synthesized and tested for antimicrobial activity. All the compounds exhibited fungicidal activity against several Candida species at concentrations ranging between 2 and 4 μg/ml. Moreover, acrylic denture base resins fabricated to contain 1, 2, or 4 wt% DABCO compounds inhibited surface C. albicans biofilm formation, as well as fungal growth, in disc diffusion assays. Remarkably, discs (4 wt%) aged for 2 months also exhibited approximately 100% growth-inhibitory activity. While some DABCO compounds exerted intermediate to high cytotoxicity against mammalian oral cell types, DC11MAF and denture base resin discs containing 2 or 4 wt% C2DC11MAF exhibited relatively low cytotoxicity against periodontal ligament (PDL) cell and gingival fibroblast (GF) lines, as well as primary oral epithelial cells. These studies demonstrate that DABCO derivatives can be incorporated into denture materials and exert fungicidal activity with minimal cytotoxicity to mammalian cells. DC11MAF and C2DC11MAF are considered strong candidates as therapeutic or preventive alternatives against Candida-associated denture stomatitis.

Cross-trienamines in Asymmetric Organocatalysis

Cross-conjugated trienamines are introduced as a new concept in asymmetric organocatalysis. These intermediates are applied in highly enantioselective Diels–Alder and addition reactions, providing functionalized bicyclo[2.2.2]octane compounds and γ′-addition products, respectively. The nature of the transformations and the intermediates involved are investigated by computational calculations and NMR analysis.

ChemInform Abstract: Preparation of Bridgehead-Substituted Bicyclo(3.3.0)octane Derivatives by the BF3×OEt2-Catalyzed Rearrangement of Bicyclo(3.2.1)oct-6- en-8-ols.

6-t-Butyldimethylsilyl-7-methylthiobicyclo[3.2.1]oct-6-en-8-ol derivatives prepared from the [2+2] cycloadducts of 1-t-butyldimethylsilyl-2-methylthioacetylene and 2-cyclohexenones are rearranged by the treatment with BF3·OEt2 into two types of bicyclo[3.3.0]octane compounds, bicyclo[3.3.0]oct-3-en-2-one or 2-methylenebicyclo[3.3.0]oct-3-ene derivatives selectively, depending on the substituent at C-1 position.

Gomadalactones A, B, and C: Novel 3‐Oxabicyclo[3.3.0]octane Compounds in the Contact Sex Pheromone of the White‐Spotted Longicorn Beetle, Anoplophora malasiaca.

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Gomadalactones A, B, and C: novel 3-oxabicyclo[3.3.0]octane compounds in the contact sex pheromone of the white-spotted longicorn beetle, Anoplophora malasiaca

The ether extract of the females of white-spotted longicorn beetle Anoplophora malasiaca showed activity as contact sex pheromone to males. The extract was fractionated, and a pheromonal activity was revealed only when three fractions; n-hexane, n-hexane/EtOAc 9:1, and EtOAc were blended. The relative structures of gomadalactone A, B, and C, three active components isolated from the EtOAc fraction, were determined by spectroscopic studies to be (1 S ∗,4 R ∗,5 S ∗)-5-hydroxy-4-[( E)-7-hydroxy-4-methylhept-3-enyl]-4,8-dimethyl-3-oxabicyclo[3.3.0]octan-7-en-2,6-dione, (1 R ∗,4 R ∗,5 R ∗)-5-hydroxy-4-[( E)-7-hydroxy-4-methylhept-3-enyl]-4,8-dimethyl-3-oxabicyclo[3.3.0]octan-7-en-2,6-dione, and (1 S ∗,4 R ∗,5 S ∗,8 S ∗)-5-hydroxy-4-[( E)-7-hydroxy-4-methylhept-3-enyl]-4,8-dimethyl-3-oxabicyclo[3.3.0]octan-2,6-dione, respectively.

Cis‐1‐phosphabicyclo[3.3.0]octan

AbstractA new approach to 1‐phosphabicyclo[3.3.0]octane compounds starts from the reaction of 4‐chloro‐hepta‐1.6‐diene with Mg in THF. No Grignard rearrangement is observed. The Grignard reagent is converted into 1‐allyl‐3‐butenylphosphonous dichloride followed by reduction with LiAlH4. Cis‐1‐phosphabicyclo[3.3.0]octane has been prepared by radical‐initiated cyclization of 1‐allyl‐3‐butenylphosphane. The bicyclic phosphane is characterized by analytical data as well as 31P and 13C NMR measurements and the reactionswith NO, S8, KSeCN, CH3I, Ni(CO)4 and HSO3F, respectively.

Development of new chiral building blocks for synthesis of bicyclo[3.3.0]octane compounds.

Ti(II)-mediated tandem cyclization of (E)-5-(tert-butyldimethylsilyloxy)-8-trimethylsilyl-2-octen-7-ynoate (7) prepared from commercially available optically active epichlorohydrin (2) proceeded diastereoselectively to provide 7-(tert-butyldimethylsilyloxy)-2-trimethylsilylbicyclo[3.3.0]oct-1-en-3-one (1), which serves as a useful chiral building block or intermediate to prepare a variety of compounds having a bicyclo[3.3.0]octane framework.

Carborane-containing liquid crystals: synthesis and structural, conformational, thermal, and spectroscopic characterization of diheptyl and diheptynyl derivatives of p-carboranes.

Molecular and electronic structures for four p-carborane derivatives were studied in the context of their liquid crystalline properties. Thus molecular and crystal structures of diheptyl and diheptynyl derivatives of 10- and 12-vertex bi-p-carboranes were determined by X-ray crystallography and compared to the results of ab initio calculations at the HF/6-31G level of theory. Experimentally observed significant positional disorder of one of the substituents in the 10-vertex derivatives, 2[2]a and 2[2]b, was related to conformational properties of the alkyl-carborane bond. Experimental and theoretical studies of the electronic structures were conducted for the four compounds using UV and NMR spectroscopies. The nature of the unique long wavelength absorption band at 232 nm in the diheptynyl derivative 2[2]b was explained using INDO/2//HF/6-31G analysis. The complete assignment of the (13)C signals was accomplished using a long-range coupling technique and was supported by the calculated (HF/6-31G) isotropic shielding tensors. Analysis of absorption spectra, NMR substituent effects, and trends in bond lengths shows generally strong cage-acetylene electronic interactions for the 10-vertex p-carborane, while the 12-vertex p-carborane remains largely electronically isolated. Ab initio calculations revealed that 12-vertex p-carborane has significantly larger electronic polarizability and quadrupole moments than the 10-vertex analogues, which are larger than those for bicyclo[2.2.2]octane compounds. All these results on packing, conformational, and electronic properties form the basis for the discussion of thermal behavior of the four carborane compounds, bicyclo[2.2.2]octane analogues, and some related compounds.

Construction of bicyclo[2.2.2]octane ring system via homoallyl-homoallyl radical rearrangement

We designed a sequential three-step, one-pot reaction (homoallyl-homoallyl radical rearrangement reaction) to generate highly functionalized bicyclo[2.2.2]octane ring system, and succeeded in developing a novel synthetic method to bicyclo[2.2.2]octane compounds from simple cyclohexene derivatives.

ChemInform Abstract: Double Michael Addition Reaction of Oxophorone and Its Derivatives Leading to Bicyclo[2.2.2]octane Compounds.

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Double Michael addition reaction of oxophorone and its derivatives leading to bicyclo[2.2.2]octane compounds

Trimethylsilylenol ethers of oxophorone 1 and its derivatives provided bicyclo[2.2.2]octane compounds 5 in a selective way.

Preparation of Bridgehead Substituted Bicyclo[3.3.0]octane Derivatives by the BF3·OEt2-Catalyzed Rearrangement of Bicyclo[3.2.1]oct-6-en-8-ols

Abstract 6-t-Butyldimethylsilyl-7-methylthiobicyclo[3.2.1]oct-6-en-8-ol derivatives prepared from the [2+2] cycloadducts of 1-t-butyldimethylsilyl-2-methylthioacetylene and 2-cyclohexenones are rearranged by the treatment with BF3·OEt2 into two types of bicyclo[3.3.0]octane compounds, bicyclo[3.3.0]oct-3-en-2-one or 2-methylenebicyclo[3.3.0]oct-3-ene derivatives selectively, depending on the substituent at C-1 position.

Stereoselective synthesis of 3,7- and 2,6-dioxabicyclo[3.3.0]octane systems by iodoetherification of diene diols

Perhydrofurofuran (2,6and 3,7-dioxabicyclo[Y3.0]octane) systems are typical structural fragments of lignans I and metabolites of some red algae. 2,3 However, until recently the synthesis of such systems remained an untrivial problem. We have developed a simple way to construct both 2,6and 3,7-dioxabicyclo[3.3.0]octane compounds by intramolecular electrophilic cyclization of diene diols 1 and 2 containing double bonds in the ~,,6-position relative to each hydroxyl. We have found that cyclization 4,s of 2,3-divinyl-l,4diols ~ 1 under the action of 12 NaHCO 3 in an ether water system proceeds stereospecifically to form only one isomer of the corresponding 2,2,6,6-tetrasubstituted cisfused 4,8-di-exo(iodomethyl)3,7-dioxabicyclo[ 3.3.0]octane 3 in 60--80% yield (Scheme 1). Under similar conditions 3,4-dimethylene1,6-diols 2 prepared by allylborylation of carbonyl compounds with 2 ,3-b i s (d ipropylbory lmethyl ) 1 ,3-butadiene 7 yield 3 ,3 ,7 ,7te t rasubst i tu ted 1,5-cis-di(iodomethyl)-2,6dioxabicyclo[3.3.0]octanes (4) along with an unsaturated bicyclic diether 5 (2,2,6,6-tetrasubstituted 3,7-dioxa1,2,3,4,5,6,7,8-octahydronaphthalene) containing no iodine. It should be noted that only 5 (R = Ph) is formed in 75% yield from the tetraphenyl derivative 2c. Compound 5 is likely to be formed due to two intramolecular processes: 1,4-conjugated addition of iodine and hydroxyl oxygen to the diene system followed by nucleophilic substitution of iodine by the oxygen atom of the second hydroxyl group. The structure of the compounds obtained was established on the basis of IH and 13C NMR spectral data, high resolution mass-spectra, and elemental analysis. Compound 3a, m.p. 98-101~ (hexane). Found,%: C 33.00; H 5.02; I 56.74. C12H2oI20 2 Calculated,%: C 32.02; H 4.48; I 56.39. lH NMR spectrum (6,

連続的多重マイケル反応によるアヌレーション テルペノイド合成の一断面

The kinetic enolates or trimethylsilyl enol ethers of 1-acetylcyclohexene undergo successive double Michael reactions with α, β-unsaturated carbonyl compounds to give substituted decalones. The kinetic enolates of cyclohexenone provide bicyclo [2.2.2] octane derivatives via double Michael reaction. These double Michael reactions have been extended to bicycloannulation leading to tricyclo [4.4.0.01.5] decane or tricyclo [3.2.1.02.7] octane compounds by employing α-bromo-α, β-unsaturated esters with cyclohexenone or 1-acetylcyclohexene, respectively. Divinylketone and the trimethylsilyl enol ethers of cyclohexenone undergo Lewis acid assisted triple Michael reactions yielding tricyclo [5.3.1.03.8] undecane derivatives. These successive multifold Michael reactions have enabled the synthetic studies of e-cadinene, khusitone, khusilal, isoeremolactone, ishwarane, and seychellene.

ChemInform Abstract: Bicyclo(2.2.2)octane Compounds in Pharmaceutical Research

ChemInformVolume 18, Issue 2 Reviews ChemInform Abstract: Bicyclo(2.2.2)octane Compounds in Pharmaceutical Research G. BUCHBAUER, G. BUCHBAUER Inst. Pharm. Chem., Univ. Wien, A-1090 Wien, AustriaSearch for more papers by this authorH. SPREITZER, H. SPREITZER Inst. Pharm. Chem., Univ. Wien, A-1090 Wien, AustriaSearch for more papers by this authorC. + MUELLAUER, C. + MUELLAUER Inst. Pharm. Chem., Univ. Wien, A-1090 Wien, AustriaSearch for more papers by this author G. BUCHBAUER, G. BUCHBAUER Inst. Pharm. Chem., Univ. Wien, A-1090 Wien, AustriaSearch for more papers by this authorH. SPREITZER, H. SPREITZER Inst. Pharm. Chem., Univ. Wien, A-1090 Wien, AustriaSearch for more papers by this authorC. + MUELLAUER, C. + MUELLAUER Inst. Pharm. Chem., Univ. Wien, A-1090 Wien, AustriaSearch for more papers by this author First published: January 13, 1987 https://doi.org/10.1002/chin.198702357Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue2January 13, 1987 RelatedInformation

Ring-cleavage Reactions of Aromatic Hydrocarbons Studied by FT–IR Spectroscopy. II. Photooxidation of o-, m-, and p-Xylenes in the NOx–Air System

Abstract α-Dicarbonyl compounds produced in the photooxidation of o-, m-, and p-xylenes were analyzed quantitatively using long-path FT–IR spectroscopy. Glyoxal, methylglyoxal, and biacetyl were observed in the case of o-xylene, and glyoxal and methylglyoxal were observed in cases of m- and p-xylenes. Yields of glyoxal, methylglyoxal, and biacetyl were 8, 23, and 10% (mole/mole) of o-xylene consumed, respectively. Yields of glyoxal and methylglyoxal were 13 and 42% in the case of m-xylene, and 24 and 12% in the case of p-xylene. These yields could be explained by the ring cleavage of 6,7-dioxabicyclo[3.2.1]octane compounds of OH–aromatics-O2 adduct. Formations of maleic anhydride was observed in the case of o-xylene and it is suggested that maleic anhydride is produced from cis-2-butenedial. Formation of 3-hexene-2,5-dione (unsaturated γ-dicarbonyl) was observed from p-xylene. The ring-cleavage process accounts for 41, 55, and 36% of the total reaction in o-, m-, and p-xylenes, respectively.

Confirmation of the E and Z attribution to the isomers of 3‐ethylidene‐1‐azabicyco‐[2,2,2]octane by CMR spectroscopy

AbstractCMR spectra of the following bicyclo[2,2,2]octane compounds were measured: 1‐azabicyclo[2,2,2]octan‐3‐one (3), 2‐azabicyclo[2,2,2]octan‐3‐one (5), bicyclo[2,2,2]octaone (4), 3‐ethyl‐1‐azabicyclo[2,2,2]oct‐2‐ene (6) and of the Z and E isomers of 3‐ethylidene‐1‐azabicyclo‐[2,2,2]octane (1 and 2). The attribution of the signals and confirmation of the Z and E configuration of isomers (1) and (2) is described.