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     

Ring opening and closing reactions of imidazoles and other 1,3-diazaheterocycles with vinyl chloroformate and phenyl chloroformate

Treatment of imidazole and benzimidazole with vinyl chloroformate or phenyl chloroformate in weakly alkaline aqueous solution leads to their conversion into the corresponding imidazol-2-ones; in weakly acidic solutions these chloroformates convert adenine into isoguanine, 6-methylaminopurine into 1-methylisoguanine and pyrimidine into an acyclic product.     

Electrophilic reactions of halides of group vi elements. 7. Reactions of allylbenzene and allyl phenyl ether with selenium tetrahalides

The reaction of selenium tetrachloride with allylbenzene and allyl phenyl ether proceeds in accordance with the Markownikoff rule to give 1:2 adducts. The use of selenium tetrabromide changes the course of the reaction and leads to the production of a mixture of adducts in accordance with and counter to the Markownikoff rule, as well as products of cyclization of the intermediate monoadducts to 2-bromomethyl-2,3-dihydrobenzo[b]selenophene or 2-bromomethyl-benzo-1,4-selenoxane derivatives.See [1–6] for previous communications.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 911–913, July, 1982.     

Sequence-regulated oligomers and polymers by living cationic polymerization. III. Synthesis and reactions of sequence-regulated oligomers with a polymerizable group

New sequence-regulated macromonomers ( 3 ) with a vinyl ether terminal were prepared by the HI/ZnI₂-mediated living cationic polymerization of vinyl ethers: CH₃? CH(OR¹)? CH₂CH(OR²)? C(COOEt)₂CH₂CH₂OCH?CH₂ ( 3a : R¹ = nBu, R² = CH₂CH₂OCOPh; 3b : R¹ = iOct, R² = CH₂CH₂Cl). The synthesis consisted of three consecutive steps: (i) quantitative addition of hydrogen iodide to the first vinyl ether into an adduct [CH₃? CH(OR¹)? l]; (ii) propagation of a second vinyl ether from the adduct in the presence of zinc iodide; and (iii) quenching the resulting AB-type heterodimeric living intermediate with a carbanion [^θC(COOEt)₂CH₂CH₂OCH?CH₂] carrying a vinyl ether group. The HI/ZnI₂-initiated living cationic polymerization of 3a and 3b yielded narrowly distributed polymers $\left( {\overline {DP}} _{_n } \sim 10 \right)$ consisting of a poly(vinyl ether) backbone and sequence-regulated oligomer branches. The terminal vinyl ether function of 3 was also utilized to prepare pentamers and hexamers with controlled sequence of functional vinyl ethers by selective dimerization and chain extension reactions with HI/ZnI₂. © 1993 John Wiley & Sons, Inc.     

Living cationic polymerization of azobenzene‐containing vinyl ether and its photoresponsive behavior

The living cationic polymerization of 4‐[2‐(vinyloxy)ethoxy]azobenzene (AzoVE) was achieved with various Lewis acids in the presence of an ester as an added base. When Et_1.5AlCl_1.5 was used as a catalyst, the living polymerization system was controllable by UV irradiation as a result of cis and trans isomerization of the azobenzene side groups. Furthermore, an initiating system consisting of SnCl₄ and EtAlCl₂ realized fast living polymerization of AzoVE. The polymerization rate of this system was 3 orders of magnitude faster than that obtained with Et_1.5AlCl_1.5. Poly(4‐[2‐(vinyloxy)ethoxy]azobenzene) was soluble in a diethyl ether/hexane mixture at 25 °C but became insoluble upon irradiation with UV light. This phase‐transition behavior was sensitive and reversible upon irradiation with UV or visible light and reflected the change in polarity occurring with cis and trans isomerization of the azobenzene side groups in the polymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5138–5146, 2005     

Structure-reactivity correlations in nucleophilic substitution reactions of Y-substituted phenyl X-substituted benzoates with anionic and neutral nucleophiles

A kinetic study is reported for the reactions of 4-nitrophenyl X-substituted benzoates (1a-1) and Y-substituted phenyl benzoates (2a-1) with two anionic nucleophiles (OH(-) and CN(-)) and three amines (piperidine, hydrazine, and glycylglycine) in 80 mol% H(2)O-20 mol% dimethyl sulfoxide (DMSO) at 25.0 +/- 0.1 degrees C. Each Hammett plot exhibits two intersecting straight lines for the reactions of 1a-1 with the anionic nucleophiles and piperidine, while the Yukawa-Tsuno plots for the same reactions are linear. The Hammett plots for the reactions of 2a-1 with hydrazine and glycylglycine demonstrate much better linear correlations with sigma(-) constants than with sigma degrees or sigma constants, indicating that the leaving group departure occurs at the rate determining step (RDS). On the contrary, sigma(-) constants result in poorer Hammett correlation than sigma degrees constants for the corresponding reactions with OH(-) and CN(-), indicating that the leaving group departure occurs after the RDS for the reactions with the anionic nucleophiles. The large rho(X) value (1.7 +/- 0.1) obtained for the reactions of 1a-1 with the anionic nucleophiles supports the proposal that the reactions proceed through an addition intermediate with its formation being the RDS.     

Reactions of ethoxyethynylphosphines with phenyl azide and nucleophiles. 1,5-Alkylotropic migration in phosphorus(IV)-substituted ketene acetals

Ethoxyethynyl-di-tert-butylphosphine reacts with phenyl azide in the presence of amines, alcohols, phenol, or water by addition of the nucleophile to the triple bond of the unstable ethoxyethynyldi-tert-butyl-N-phenyliminophosphorane. It has been found that iminophosphorylated ketene acetals are usually unstable, undergoing 1,5-alkylotropic migration to give alkoxycarbonylmethyl-ene(alkylphenylamino)phosphoranes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2850–2855, December, 1991.     

Reactions of N-alkylazinium cations. 3. Quaternary pteridinium salts. Synthesis,structure, and reactions with simple nucleophiles

4-Morpholinopteridine reacts with triethyloxonium tetra-fluoroborate to give two types of isomeric quaternary salts, viz., 1-ethyl- and 8-ethyl-4-morpholinopteridinium tetrafluoroborates. The structures of the pteridinium cations were proved by the ¹H and ¹³C NMR spectra and also by chemical transformations in reactions with simple nucleophiles.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1257–1264, September, 1985.     

Reactions of cationic rhodium(I) carbonyl compounds with nucleophiles to form alkoxo,carboalkoxy and carboxylato complexes. Part II

Summary The rhodium(I) carbonyl compounds [Rh(CO)L₂2] [BF₄]. 1/2CH₂Cl_nn2 (L = PPh₂ or AsPh₃) react with the nucleophiles OMe⁻, RCOO⁻ (R = Me, Et) under nitrogen to form [Rh(OR)(CO)L₂] (1)–(2) and [Rh(OOCR)(CO)L₂] (7)–(₁₀), respectively. Addition of [Rh(CO)₂(PPh₃)₂]-[BF ₄] to OMe⁻ under nitrogen produces [Rh(COOMe)-(CO) (PPh₃)₂]-MeOH (3), whilst reactions of [Rh(CO)-(PPh₃)₂] [BF₄]·1/2CH₂Cl₂ and [Rh(CO)₂(PPh₃)₂] [BF₄] with OR_- (R = Me, Et or n-Pr) in the presence of CO produce [Rh(COOR)(CO)₂(PPh₃)₂] (4)–(6). The products have been characterised by i.r., ¹H, ³¹P, ¹³Cn.m.r. spectroscopy and elemental analysis.     

Reactions of tetrafluoroethene oligomers. Part 4. Some reactions of the major hexamer oligomer with nucleophiles based on oxygen and sulphur

The major hexamer oligomer of tetrafluoroethene [perfluoro-2-(1-ethyl-1-methylpropyl)-3-methyl-pent-1-ene] (1) reacted with sodium hydroxide under vigorous conditions to afford perfluoro-[(1-ethyl-1-methylpropyl) (1-methylpropyl)]keten (3). Reaction of (1) with methoxide ion in methanol afforded 4-methoxycarbonyl-heneicosafluoro-3,5-dimethyl-5-ethyl-hept-3-ene (5) whereas reaction with methanol In the presence of triethylamine initially afforded (5), but on further reaction yielded (E, Z)-4H-heneicosafluoro-3,5-dimethyl-5-ethylhept-3-ene (4). Reaction of (1) with potassium-t-butoxide in t-butanol afforded (3) whilst with water/triethylamine (4) was obtained. With ethanethiol and sodium benzylthiolate, respectively, hexamer (1) gave ethyl and benzyl [tricosafluoro-3-ethyl-3-methyl-2-(1-methylpropyl)pent-1-enyl]sulphides (6) and (7). With aqueous potassium cyanide 1-cyanotricosafluoro-3-ethyl-3-methyl-2-(1-methylpropyl)pent-1-ene (8) was obtained.     

Reactions of azinium cations. 8. Electron structures of 3-substituted 1,2,4-triazines and protonation,quaternization, and reactions with nucleophiles

The electron structures of 3-substituted 1,2,4-triazines and isomeric N-methyltriazinium salts were calculated by the CNDO/2 method. The results of the calculations were compared with the parameters of the ¹³C, ¹⁵N, and ¹⁴N NMR spectra, as well as with experimental data on the protonation, N-alkylation, and reactions of 1,2,4-triazines with simple nucleophiles. The protonation centers of 1,2,4-triazines were determined by means of ¹H, ¹³C, and ¹⁴N NMR spectroscopy. The covalent adducts formed by the proton salts of 3-methoxy-, 3-methylthio-, 3-morpholino-, and 3-pyrrolidino-1,2,4-triazine with water and methanol were recorded by ¹H NMR spectroscopy.Communication 7: O. N. Chupakhin, V. N. Chaurushin, I. V. Kazantseva, M. G. Poinzovskii, E. O. Sidorov, P. A. Torgashev, and A. V. Belik, Khim. Geterotsikl. Soedin., No. 10, 1385 (1987).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 525–533, April, 1988.     

Reactions of 2,2,4,4-tetramethyl-1,3-cyclobutanedione with amines and other nucleophiles. II

The reaction of 2,2,4,4-tetramethyl-1,3-cyclobutanedione with various nucleophiles has been demonstrated to be dependent on the reaction conditions, steric factors and the nucleophilicity of the attacking species. In the reaction with primary amines the intermediate has been established as the N-substituted imine which is hydrolyzed to the corresponding amide in the presence of water. The reaction of diamines with the dione has been shown to be a method of synthesizing 2-substituted imidazolines and 1 H-4,5-dihydropyrimidines.     

Vinyl ethers with a functional group: Living cationic polymerization and synthesis of monodisperse polymers

The living cationic polymerization of vinyl ethers (VEs) having a (polar) functional pendant has been achieved by the hydrogen iodide/iodine (HI/I₂) initiating system to give polymers with a very narrow molecular weight distribution (MWD) (M_w/M_n ≤ 1.2). The functional pendants include benzyl, saturated or unsaturated ester, (poly) oxyethylene, and substituted phenoxyl groups. Although these polar groups often disturb cationic vinyl polymerization by inducing chain transfer and termination, the HI/I₂ initiator cleanly polymerized the “functionalized” VEs without side reactions, mostly in nonpolar media at low temperatures below −15 °C. The HI/I₂-initiated living polymerization also provided facile methods to synthesize new functional polymers, including water-soluble polymers, macromolecular amphiphiles, and macromers, all having a narrow MWD. The simplest example is the living polymerization of VEs carrying an oxyethylene chain [-(CH₂CH₂O)_n-R] as pendant, which directly yields water-soluble polymers. The debenzylation of poly(benzyl VE) prepared with HI/I₂ led to poly(vinyl alcohol). Polymers of the saturated ester-containing monomers (2-acetoxyethyl and 2-benzoyloxyethyl VEs) were readily hydrolyzed into poly (2-hydroxyethyl VE), soluble in water and swellable in methanol. This lead was extended to the synthesis of a new amphiphile, poly(cetyl VE-b-2-hydroxyethyl VE), from a block copolymer of cetyl and 2-acetoxyethyl VEs prepared by their sequential living polymerization initiated with HI/I₂. An adduct between HI and 2-vinyloxyethyl methacrylate [CH₃-CH(I)-OCH₂CH₂OCOC(CH₃) =CH₂] was found to initiate living polymerizations of VEs in the presence of iodine; the products were methacrylate-type macromers carrying a poly(VE) side chain with a narrow chain-length distribution.     

Radical polymerization behavior of a vinyl monomer bearing five‐membered cyclic carbonate structure and reactions of the obtained polymers with amines

Radical polymerization behavior of a vinyl substituted cyclic carbonate, 4‐phenyl‐5‐vinyl‐1,3‐dioxoran‐2‐one ( 1 ), is described. Radical polymerization of 1 proceeded through selective vinyl polymerization to produce polymers bearing carbonate groups in the side chain, in contrast to that of an oxirane analogue of 1 , 1‐phenyl‐2‐vinyl oxirane that proceeds via the selective ring‐opening fashion. Although the homopolymerization of 1 produce polymers in relatively lower yield, copolymerizations effectively provided cyclic carbonate‐containing copolymers. Nucleophilic addition of primary amines to the resulting homopolymers and copolymers produced the corresponding multifunctional polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 584–592, 2005     

Reactions of azirines with sulfur nucleophiles. 4. Treatment of 2H-azirine with mercaptosubstituted acids. reactions of aziridinyl alkyl sulfides with carboxylic acids and acyl chloride derivatives

Treatment of 2H-azirines with mercaptosubstituted acids and their derivatives leads to -ketoamides and 2-aziridinyl alkyl sulfides, respectively. 2-Aziridinyl alkyl sulfides, in turn, react with carboxylic acids to give -ketoamides and substituted ethanethiol derivatives. Acylation of 2-aziridinyl alkyl sulfides with acyl halides generates a variety of products, depending on the reaction conditions; either products derived from cleavage and isomerization of the aziridinyl ring or (1-acylaziridinyl-2) alkyl sulfides are obtained.For communication 3, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 206–211, February, 1986.     

Synthesis and cationic ring-opening polymerization of mono- and bifunctional spiro orthoesters containing ester groups and depolymerization of the obtained polymers: An approach to chemical recycling for polyesters as a model system

A spiro orthoester having an ester moiety, 2-acetoxymethyl-1,4,6-trioxaspiro[4.6]undecane (4) was synthesized, and its cationic polymerization and depolymerization of the obtained polymer (5) were carried out. The monomer 4 underwent cationic polymerization with a cationic catalyst to afford the corresponding poly(cyclic orthoester) 5. The obtained polymer 5 could be depolymerized with a cationic catalyst to regenerate the monomer 4 in an excellent yield. Further, bifunctional spiro orthoesters (6, 8, 9) having diester moieties were synthesized from terephthalic acid, succinic acid, and 1,4-cyclohexanedicarboxylic acid, and their acid-catalyzed reversible crosslinking–decrosslinking was examined. The bifunctional monomer 6 derived from terephthalic acid underwent cationic crosslinking to afford the corresponding network polymer (7), which could be also depolymerized to regenerate the original bifunctional monomer 6. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2551–2558, 1999     

Ethynyl carbonium ions. 2. Reactions of 4-ethynylpyrylium perchlorates with alcohols and nitrogen-containing nucleophiles

Derivatives of -alkoxy- and -(phenylamino)styrylpyrylium salts, the hydrolysis of which leads to phenacylpyrylium salts and 4-benzoylmethylenepyrans, are formed in the reaction of 4-phenylethynylpyrylium salts with alcohols and aromatic amines. Ethynyl-substituted pyridines and pyridinium salts were synthesized by the action of ammonium acetate and methylamine, benzylamine, and butylamine. A -methylaminostyryl-1-methyl-substituted pyridinium salt is formed with excess methylamine.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 299–306, March, 1990.     

Living cationic polymerization of vinyl ethers with a functional group. VII. Polymerization of vinyl ethers with a silyloxyl group and synthesis of polyalcohols and related functional polymers

Living cationic polymerizations of two silicon-containing vinyl ethers, 2-(t-butyldimethyl-silyloxyl)ethyl vinyl ether (tBuSiVE) and 2-(trimethylsilyloxyl)ethyl vinyl ether (MeSiVE), have been achieved with use of the hydrogen iodide/iodine (HI/I₂) initiating system in toluene at ?15 or ?40°C, despite the existence of the acid-sensitive silyloxyl pendants. The living nature of the polymerizations was demonstrated by linear increases in the number-average molecular weights (M?_n) of the polymers in direct proportion to monomer conversion and by their further rise upon addition of a second monomer feed to a completely polymerized reaction mixture. The polymers obtained in these experiments all exhibited very narrow molecular weight distributions (MWD) with M?_w/M?_n around or below 1.1. Desilylation of the polymers under mild conditions (with H⁺ for MeSiVE and F^? for tBuSiVE) gave poly(2-hydroxyethyl vinyl ether), a water-soluble polyalcohol with a narrow MWD. The living processes also permitted clean syntheses of amphiphilic AB block copolymers and water-soluble methacrylate-type macromonomers, all of which bear narrowly distributed segments of the polyalcohol derived from the silicon-containing vinyl ethers.