Model reactions of functionalization of polycarbonate. Reactions of phenyl chloroformate with nucleophiles and cationic polymerization behavior of bicyclo orthoesters containing carbonate group

Some model experiments for functionalization of a polycarbonate were carried out. At first, reactivity of phenyl chloroformate with a few nucleophiles was examined. Reaction with alkyl amines gave corresponding carbamates, but in the case of aniline, formation of a byproduct diarylurea was observed. Reactions with alcohols and phenols afforded carbonates in moderate yields, in which p-nitrophenol and isopropyl alcohol were less reactive. On the basis of these results, 1-ethyl-4-phenoxycarboxymethyl-2,6,7-trioxabicyclo[2.2.2]octane (2) and 1-ethyl-4-ethoxycarboxymethyl-2,6,7-trioxabicyclo[2.2.2]octane (3) were prepared by the reaction of phenyl and ethyl chloroformates with 1-ethyl-4-hydroxymethyl-2,6,7-trioxabicyclo[2.2.2]octane in the presence of tert-amine. 2 polymerized cationically with BF₃OEt₂ at more than 80°C to give a polyether containing both ester and carbonate groups in the side chain, with contamination of a gelled polymer.     

Equilibrium polymerization behavior in the cationic single ring‐opening polymerization of bicyclo orthoesters

The synthesis and cationic polymerization of the following bicyclo orthoesters were examined: 4‐ethyl‐2,6,7‐trioxabicyclo[2.2.2]octane, 1,4‐diethyl‐2,6,7‐trioxabicyclo[2.2.2]octane, 4‐ethyl‐1‐phenyl‐2,6,7‐trioxabicyclo[2.2.2]octane, 4‐ethyl‐1‐(4‐methoxyphenyl)‐2,6,7‐trioxabicyclo[2.2.2]octane, and 4‐ethyl‐1‐(4‐nitrophenyl)‐2,6,7‐ trioxabicyclo[2.2.2]octane. All the monomers underwent equilibrium polymerization, which was confirmed by the relationships between the polymerization temperature and monomer conversion. The obtained polymers afforded the original monomers via an acid‐catalyst treatment with a low reagent concentration in CH₂Cl₂ at 20 °C. The equilibrium monomer concentration was constant, regardless of the initial reagent concentration, in both polymerization and depolymerization. The bicyclo orthoesters with a bulky and electron‐withdrawing substituent showed a larger equilibrium monomer concentration. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3159–3167, 2001     

The synthesis,characterization, and polymerization of 1-ethyl-4-[(2-methacryloxy)ethyl carbamoyloxymethyl]-2,6,7-trioxabicyclo[2.2.2]octane

The synthesis of a monomer bearing polymerizable acrylic and bicyclic ortho ester groups is described. The monomer 1-ethyl-4-[(2-methacryloxy)ethyl carbamoyloxymethyl]-2,6,7-trioxabicyclo[2.2.2]octane is characterized by elemental analysis, ¹H- and ¹³C-NMR spectra, mass spectra, and heat of polymerization. The free-radical and ionic polymerization of 4 is probed as is its copolymerization with several vinyl monomers.     

Cationic polymerization of 1-phenyl-4-ethyl-2,6,7-trioxabicyclo[2.2.2]octane

Cationic polymerization of bicyclo ortho ester, 1-phenyl-4-ethyl-2,6,7-trioxabicyclo[2.2.2]octane, was carried out with Lewis acids and cation sources to obtain the polyether containing ester group in the side chain. It was found that boron trifluoride etherate was the most active initiator in the Lewis acids. Magnesium perchlorate and triphenylcarbenium tetrafluoroborate, which have lower nucleophilic counter ions, initiated effectively the polymerization of bicyclo ortho ester.     

Synthesis of a well-defined cyclic polystyrene via α-carboxyl, ω-amino heterodifunctional polystyrene

Living anionic polymerization of styrene was carried out in benzene at room temperature using 1-(3-lithiopropyl)-4-methyl-2,6,7-trioxabicyclo[2.2.2]octane and 2,2,5,5-tetramethyl-1-(3-bromopropyl)-1-aza-2,5-disilacyclopentane as an initiator and terminator, respectively, to obtain α-2,2-bis(hydroxymethyl)propoxycarbonyl, ω-amino heterodifunctional polystyrene. It was hydrolyzed to α-carboxyl, ω-amino heterodifunctional polystyrene which gave a well-defined cyclic polystyrene by the intramolecular cyclization under high dilution conditions. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2027–2033, 1999     

双环笼状四配位硅的合成及其结构表征

研究了以SiO₂为原料低温合成高反应活性的五配位硅酸酯, 并与1-氧代-1-磷杂-2,6,7-三氧杂双环[2.2.2]-4-氯甲基辛烷反应合成出具有对称结构的双环笼状四配位硅, 通过红外光谱、¹³C和²⁹Si固体核磁共振、质谱等测试手段确定了其结构. 热分析结果表明, 双环笼状四配位硅在700 ℃的失重仅为19.98%, 且炭层呈密实片层状, 说明目标产物具有优异的热稳定性和成炭性质.     

A stereoselective synthesis of 3-substituted (S)-pyroglutamic and glutamic acids via OBO ester derivatives

(S)-Pyroglutamic acid is transformed to the Cbz-protected 4-methyl-2,6,7-trioxabicyclo[2.2.2] octane (OBO) ester. This ortho ester functionality is employed as a bulky steering group for stereoselective introduction of alkyl and aryl groups via 1,4-cuprate addition to 3,4-unsaturated pyroglutamates. After deprotection and ringopening, 3-substituted glutamic acids are obtained.     

Study of the initial stages of alkoxo synthesis involving Ti(OBu)4 and cyclophosphites

The reactivities of cyclophosphite precursors in alkoxo syntheses involving titanium(iv) tetra(n-butoxide) were studied by ³¹P NMR and IR spectroscopy. 2-Diethylamido-4-methyl-1,3,2-dioxaphosphinane and 4-ethyl-2,6,7-trioxaphosphabicyclo[2.2.2]octane in benzene are inert toward Ti(OBu)₄. Gelation is accompanied by hydrolysis 2-diethylamido-4-methyl-1,3,2-dioxaphosphinane to give the corresponding hydrophosphoryl compound, while 4-ethyl-2,6,7-trioxaphosphabicyclo[2.2.2]octane remains intact during gelation.     

Synthesis and Structure of A Novel Caged Bicyclic Phosphate Flame Retardant

IntroductionThe ecological safety of polymer flame retardant has become a major subject in the modern polymer industry, and there is an international demand for the control of polymer flammability without the use of halogenated additives. Consequently, current research is mainly focused on looking for environmental friendly additives in the form of organophosphorus compounds, which are being thought as the alternatives of the halogen containing flame retardants1. Among the organophosphorus fla…     

Interaction between Exocyclic s-cis-Butadiene and Homoconjugated Functions. Preparation and Diels-Alder Reactivity of Remotely Substituted 2,3-Dimethylidenebicyclo[2.2.2]octanes

The preparations of 5,6-dimethylidene-2exo-bicyclo[2.2.2]octanol ( 8 ), its endo isomer 9 , 5,6-dimethylidene-2-bicyclo[2.2.2]octanone ( 10 ) and 2 exo, 3 exo-epoxy-5,6dimethylidenebicyclo[2.2.2]octane ( 11 ) are described. The kinetics of their cycloaddition to tetracyanoethylene has been measured in toluene at 25° together with those of 2,3-dimethylidenebicyclo[2.2.2]octane ( 7 ) and 5,6-dimethylidenebicyclo[2.2.2]oct-2-ene (12). The effects of remote substitution on the Diels-Alder reactivity of 2,3-dimethyl idenebicyclo[2.2.2]octanes are compared with those observed in the 2,3-dimethylidenenorbornane series ( 1–6 ).     

Synthesis of anticonvulsant activity of some 2-phenylcarbamoyl-1,2-diazabicyclo[2.2.2]octanes

A number of aryl isocyanates were adducted to 1,2-diazabicyclo[2.2.2]octane and afforded 2-phenyl-carbamoyl-1,2-diazabicyclo[2.2.2]octanes. Some of the products displayed anticonvulsant activity.     

CONDENSATION REACTION OF 1-OXO-4-CHLOROCARBONYL-1-PHOSPHA-2,6,7-TRIOXABICYCLO[2.2.2]OCTANE WITH N-t-BUTYL-N-BENZOYLHYDRAZINE

Abstract

1-Oxo-4-chlorocarbony1-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane (5) was obtained from phosphorus oxychloride. Benzyl chloroformate was synthesized by the reaction of benzyl alcohol and triphosgene in good yield for the first time. N-r-Butyl-N-benzoylhydrazine(II) was prepared in a new and convenivent procedure with good yield. The reaction of 5 and II proceeded smoothly in the presence of sodium carbonate and afforded the desired compound 13 in good yield, while in the presence of triethylamine, the elimination of butyl was observed and afforded the compound 12.     

1-氧代-1-磷杂-2, 6, 7-三氧杂双环[2.2.2]-4-含硫取代基辛烷 的合成

本文利用中间体1-氧代-1-磷杂2,6,7-三氧杂双环[2.2.2]-4-羟甲基辛烷(1)和1-氧代-1-磷杂-2,6,7-三氧杂双环[2.2.2]-4-氯甲酰基辛烷(3)分别与RSH或取代硫醇按步骤反应得到了相应的4-亚甲基硫醚(5a～f)、4-亚甲基亚砜(6a～f)、4-(氯代乙硫基)甲酰基(7)及4-(β-烷硫基)-α-硫代酯基(8a～i)的双环笼状磷酸酯新衍生物共22个。所有的化合物经元素分析、IR和^1HNMR得到了证实。     

Oxidative Dearomatization: Synthesis of Functionalized Bicyclo[2.2.2]octenones,Sigmatropic Shift in Excited State,and Radical-Induced Cleavage of Cyclopropane Ring

Synthesis of novel bicyclo[2.2.2]octenones endowed with a β,γ-enone system in which γ-carbon is substituted with an electron-withdrawing group from simple aromatics is described. Oxa-di-pi-methane reaction of bicyclo[2.2.2]octenones to functionalized bicyclo[3.3.0]octanes and their transformation to bicyclo[3.2.1]octane framework are also presented.     

Synthesis of 1, 2-diazabicyclo [2.2.2] octane, 1, 2-diazabicyclo [3.2.1]-octane,and their derivatives

1, 2-Diazabicyclo [2.2.2] octane, its 6-methyl homolog, and 1, 2-diazabicyclo [3.2.1] octane are synthesized by a general method involving nitrosation of piperidine carboxylic acids, subsequent reduction to 1-aminopiperidine carboxylic acids, cyclization to 3-keto-1, 2-diazabicycloalkanes, reduction of the latter to 1, 2-diazabicycloalkanes. A number of 2-substituted 1, 2-diazabicyclo [2.2.2] octanes are synthesized.     

Synthesis And Biological Activities of 4-Neoalkyl-2,6,7-Trioxa-1-PhosphabicycIo[2.2.2] Octanes

4-Alkyl derivatives of 2,6,7-trioxa-1-phosphabicyclo[2.2.2] octanes are extensively used for spectroscopic studies and are candidates for use as flame retardants, vinyl resin stabilizers and antioxidants^[1-4]. Bicyclic phosphates are antagonist of GABA receptor, further research show that these compounds act on the chloride ion channel connecting with GABA receptor. So bicyclic phosphate can act as drugs to probe the Cl^- channel. Our preliminary pharmacological results indicate that these bicyclic phosphorus compounds should be handled with great care because of their high toxicity to mammals. Some derivatives of bicyclic phosphates have been prepared in our laboratory.     

Unexpectedly similar charge transfer rates through benzo-annulated bicyclo[2.2.2]octanes

A 4-(pyrrolidin-1-yl)phenyl electron donor and 10-cyanoanthracen-9-yl electron acceptor are attached via alkyne linkages to the bridgehead carbon atoms of bicyclo[2.2.2]octane and all three benzo-annulated bicyclo[2.2.2]octanes. The sigma-system of bicyclo[2.2.2]octane provides a scaffold having nearly constant bridge geometry on which to append multiple, weakly interacting benzo pi-bridges, so that the effect of incrementally increasing numbers of pi-bridges on electron transfer rates can be studied. Surprisingly, photoinduced charge transfer rates measured by transient absorption spectroscopy in toluene show no benefit from increasing the number of bridge pi-systems, suggesting dominant transport through the sigma-system. Even more surprisingly, the significant changes in hybridization undergone by the sigma-system as a result of benzo-annulation also appear to have no effect on the charge transfer rates. Natural Bond Orbital analysis is applied to both sigma- and pi-communication pathways. The transient absorption spectra obtained in 2-methyltetrahydrofuran (MTHF) show small differences between the benzo-annulated molecules that are attributed to changes in solvation. All charge transfer rates increase significantly upon cooling the MTHF solutions to their glassy state. This behavior is rationalized using combined molecular dynamics/electronic structure trajectories.     

Rapid Access to Oxabicyclo[2.2.2]octane Skeleton through Cu(I)‐Catalyzed Generation and Trapping of Vinyl‐o‐quinodimethanes (Vinyl‐o‐QDMs)†

A Cu(I)‐catalyzed three‐component reaction of terminal enynals/enynones, diazo compounds, and alkenes has been developed. With this method, a series of oxabicyclo[2.2.2]octanes were effectively synthesized in high yields under mild reaction conditions. This transformation is proposed to proceed through trapping of the cyclic vinyl‐o‐quinodimethanes (vinyl‐o‐QDMs) species, which were generated from terminal enynals/enynones and diazo compounds by alkenes. The obvious advantages of wide substrate scopes, mild reaction conditions, and high seteroselectivity and atom efficiency make this reaction highly appealing for construction of highly rigid [2.2.2]octane skeleton.     

Rubbery wound closure adhesives. II. initiators for and initiation of 2‐octyl cyanoacrylate polymerization

The polymerization of 2‐octyl cyanoacrylate (OctCA) initiated by five N‐bases [N,N‐dimethyl‐p‐toluidine (DMT), pyridine (Pyr), triethyl amine (Et₃N), azobicyclo[2.2.2]octane (ABCO), and diazobicylo[2.2.2]octane (DABCO)] was investigated. Our main objective was to assess the suitability and relative reactivity of these initiators for neat OctCA polymerization as wound closure adhesives. Methodologies were developed to determine stir‐stop and set times of OctCA polymerization and to use these quantities to assess initiation reactivity. According to these studies Et₃N, ABCO, DABCO, and Pyr are most reactive initiators, while DMT is much less reactive. Polymerizations were much faster in the presence of small amounts of tetrahydrofuran than toluene, indicating solvent polarity effects. Initiator reactivity is discussed in terms of structural parameters. NMR and MALDI‐TOF analyses of low molecular weight P(OctCA) prepared with DMT did not show evidence for the expected aromatic head group proposed by earlier investigators, which suggests complex initiation mechanism. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1652–1659     

Diazabicycloalkanes with nitrogen atoms in the nodal positions. 7. Synthesis and configuration of 2,3-diphenyl-1,4-diazabicyclo[2.2.2]-octane

The reaction of ethylene oxide with the meso and d,l diasteromers of 1,2-diphenyl-ethylenediamine gave N,N'-bis(-hydroxyethyl)-1,2-diphenylethylenediamines, which upon refluxing with SOCl₂ form N,N'-bis (-chloroethyl)-1,2-ethylenediamines. The latter upon heating in dimethylformamide (DMF) at 150 ° C undergo cyclization to give, respectivley, cis- and trans-2,3-diphenyl-1,4-diazabicyclo[2.2.2]octane. Evidence for the spatial orientation of the phenyl substituents in the diazabicyclooctanes obtained was obtained by means of an analysis of the multiplicity of the methylene protons in the PMR spectra. The vicinal spin-spin coupling constants for the benzyl protons of the isomeric 2,3-diphenyl-1,4-diazabicyclo[2.2.2]octanes in the ¹³C-H satellites were measured. The values obtained were compared with the literature data and with the dihedral angles calculated from mechanical models of the molecules.See [1] for Communication 6.Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 1. pp. 95–100. January, 1982.The authors thank V. I. Mamatyuk and Yu. V. Gatilov for their assistance in interpreting the PMR spectra and performing the mathematical calculations.