Alternating copolymerization of methyl acrylate with donor monomers having a protected amine group

Attempts were made to copolymerize p-aminostyrene, p-acetamidostyrene, N-methyl-p-aceta-midostyrene, N-(4-vinylphenyl) phthalimide, N-vinyl succinimide, and N-vinyl phthalimide with methyl acrylate complexed with ethyl aluminum sesquichloride. Only reactions involving N-(4-vinylphenyl)phthalimide and N-vinyl phthalimide yielded alternating copolymers. N-vinyl succinimide gave nonalternating copolymers insoluble in common solvents and the other monomers did not copolymerize. In some cases, the conventional radical copolymers were prepared for comparison purposes. The reactivity ratios of the free-radical initiated copolymerization of methyl acrylate (I) with N-(4-vinylphenyl)phthalimide (II) were r₁ = 0.14 and r₂ 1.56. The alternating copolymers were studied by ¹H-NMR and ¹³C-NMR spectroscopy. The alternating copolymer of N-(4-vinylphenyl)phthalimide with methyl acrylate was hydrazinolyzed to form the alternating copolymer of methyl acrylate with p-aminostyrene. Hydrazinolysis of the alternating copolymer of methyl acrylate with N-vinyl phthalimide removed the phthalimide moiety and generated vinyl amine units which readily cyclized with neighboring methyl acrylate units to form copolymers that contained five-membered lactam rings. The infrared (IR) spectra of the hydrazinolyzed products contain bands due to amine or amide groups and are devoid of the characteristic bands of the phthalimide ring.     

Photoinitiation and electroinitiation in the polymerization of 2-vinylnaphthalene

The zinc chloride-catalyzed polymerization of 2-vinylnaphthalene (VN) with both photoinitiation and electronitiation methods was examined. Good yields were obtained with both methods, the electroinitiated process being somewhat faster. The mechanism for polymerization initiation was investigated through a detailed comparison of the kinetics. Both initiation methods show a similar response to increasing input energy and to change in salt to monomer mole ratio. Both methods indicate formation of a ZnCl₂–(2-VN)₂ complex as intermediate with the formation of the species being rate-determining. These results, together with other similar investigations, are then used to deduce a mechanism that involves the formation of an electronically excited donor–acceptor complex. It is argued that in certain salt-stabilized, electron-delocalized, aromatic systems, such excitation is possible in electroinitiation.     

N-vinyl carbazole copolymers

The synthesis of N-vinyl carbazole (VCbz) copolymers, some of which contain electron-accepting groups, is described. The new copolymers are: copoly[N-vinyl carbazole-di(2-N-carbazylethyl)-fumarate](II); copoly(N-vinyl carbazole-vinyl-2,4-dinitrobenzene-sulfonate)(IV); copoly(N-vinyl carbazole-vinyl-2,4-dinitrobenzene-sulfenate)(V); copoly(n-butyl acrylate-t-butyl peracrylate)(VII); copoly(n-butyl acrylate-t-butyl acrylate-graft-N-vinyl carbazole)(VIII).     

Interaction and Scale of Mixing in Cellulose Acetate/Poly(<Emphasis Type="Italic">N</Emphasis>-vinyl Pyrrolidone-co-vinyl Acetate) Blends

Binary blends and pseudo complexes of cellulose acetate (CA) with vinyl polymers containing N-vinyl pyrrolidone (VP) units, poly(N-vinyl pyrrolidone) (PVP) and poly(N-vinyl pyrrolidone-co-vinyl acetate) [P(VP-co-VAc)], were prepared, respectively, by casting from mixed polymer solutions in N,N-dimethylformamide as good solvent and by spontaneous co-precipitation from solutions in tetrahydrofuran as comparatively poor solvent. The scale of miscibility and intermolecular interaction were examined for the blends and complexes by solid-state ¹³C-NMR spectroscopy. It was revealed that the formation of complexes was due to a higher frequency of hydrogen-bonding interactions between the residual hydroxyl groups of CA and the carbonyl groups of VP residues in the vinyl polymer component. From measurements of CP/MAS spectra and proton spin-lattice relaxation times (T_1ρ^H) in the NMR study, the existence of the hydrogen-bonding interaction was also confirmed for the miscible blends and the homogeneity of the mixing was estimated to be substantially on a scale within a few nanometers.     

Thermal reaction of ethynylphthalimides and hydration of N-(4-ethynylphenyl)phthalimide

Three ethynyl substituted phenylphthalimides were prepared and characterized by high pressure liquid chromatography, differential scanning calorimetry, and mass spectroscopy. When the preparation of N-(4-ethynylphenyl)phthalimide was attempted by the thermal cyclodehydration of N-(4-ethynylphenyl)-2-carboxybenzamide, N-(4-acetylphenyl)phthalimide was obtained as the major component. This unusual hydration of an ethynyl group was investigated and a mechanism was proposed to explain it.     

A convergent, modular access to complex amines

Various xanthates can be added to N-vinyl phthalimide with little formation of oligomers, if the xanthate is used in excess and the medium slightly diluted. The adduct xanthates thus obtained can in turn undergo radical additions to numerous olefins, providing a convergent and modular access to densely functionalized amines.     

Reactions of 4,5-diaminouracils

Reactions of 4,5-diaminopyrimidines with various phthalic derivatives, depending on the conditions employed, led to pyrimidines with a 5-N-substituted phthalamic acid (III), 5-N-substituted phthalimide (II) and 4,5-bis-N-substituted phthalimide (VI).     

A facile entry to l-aryl-4,5-dihydro[1,4]oxazepino-[5,4-a]isoindole-2,7-diones

The titled compounds were prepared by reacting N-(2-bromoethyl)phthalimide with enolates of phenylacetic acid esters. 2,3-Dihydrooxazolo[2,3-a]isoindolones are believed to be intermediates in the process. An X-ray crystallographic analysis was conducted on one of the compounds.     

Crystallization of titania ultra-fine particles from peroxotitanic acid in aqueous solution in the present of polymer and incorporation into poly(methyl methacylate) via dispersion in organic solvent

We report a novel strategy for incorporation of titanium dioxide (TiO₂) particles, which were crystallized from peroxotitanic acid in the presence of hydrophilic polymer by hydrothermal treatment in aqueous solution, into poly(methyl methacrylate) (PMMA) via dispersion into chloroform. Dispersion of TiO₂ particles into chloroform was achieved by solvent change from water to chloroform in aid of amphiphilic polymer dispersant, poly(N-vinyl pyrrolidone) (PVP), poly(N-vinyl pyrrolidone-co-methyl methacrylate) (PVP-co-PMMA), poly(N-vinyl pyrrolidone-block-methyl methacrylate) (PVP-b-PMMA) through azeotropical removal of water. Incorporation of TiO₂ particles into PMMA was carried out by a casting process of a mixture of TiO₂ particles dispersed with PVP₁₅₄-b-PMMA₁₅₆ in chloroform and PMMA on a glass substrate. Resultant hybrid film containing TiO₂ less than 10 wt.% showed high transparency in visible region attributable to homogeneous dispersion into PMMA matrix. The refractive index of the hybrid films increased with TiO₂ content and agreed with the calculated values.     

Anionic polymerization of N-ethyl-2-vinylcarbazole and N-ethyl-3-vinylcarbazole

The polymerization of N-ethyl-2-vinylcarbazole and N-ethyl-3-vinylcarbazole by an anionic mechanism has been demonstrated. Polymerization reactions were monitored by ultraviolet/visible spectroscopy and λ_max and ε values for the propagating carbanions determined. The 2-vinyl monomer exhibits all the features of a standard “living” polymer; the carbanion is stable at ambient temperatures and high molecular weight, M?_n ? 10⁶, narrow distribution polymers and block copolymers with styrene have been prepared. The carbanion from the 3-vinyl monomer is much less stable and a clean polymerization can only be conducted at temperatures below -60°C. A comparison of the anionic polymerization characteristics of the N-, 2-, and 3-vinyl carbazole monomer series is presented.     

Syntheses and polymerizations of some vinyl monomers containing nitro- or fluorophthalimides

4-Nitro-N-vinylphthalimide ( 4 ) was synthesized by two different procedures. Compound 4 was not polymerizable or copolymerizable by AIBN. Poly(N-vinylphthalimide) ( 17 ) was prepared and partially nitrated at 10–25°C. N,N′-(1,2-Ethanediyl)bis(4-nitrophthalimide) ( 15 ) and N,N′-(1,3-propanediyl)bis(4-nitrophthalimide) ( 16 ) were prepared by the condensation of the corresponding diamine with phthalic anhydride followed by nitration of the condensation products. 4-Nitrophthalic anhydride was prepared by the hydrolysis of 15 . Four styrene-substituted phthalimide monomers were synthesized. These include N-(4-vinylphenyl)phthalimide ( 25a ), N-(4-vinylphenyl)-3-fluorophthalimide ( 25b ), N-(4-vinylphenyl)-3-nitrophthalimide ( 25c ), and N-(4-vinylphenyl)-4-nitrophthalimide ( 25d ). Monomers 25a and 25b were polymerized by freeradical initiator (AIBN), whereas monomers 25c and 25d were not polymerizable or copolymerizable by AIBN due to a strong inhibitive effect exerted by the nitrophthalimide group. Monomers 25c and 25d were cationically polymerized (BF₃·OEt₂). Monomer 25b and styrene were copolymerized and their reactivity ratios were r₁ = 1.7 and r₂ = 0.55, respectively. The prepared polymers are useful as backbone polymers for grafting living anionic polymers.     

Novel thermooxidatively stable poly(ether-imide-benzoxazole) and poly(ester-imide-benzoxazole)

4-Hydroxy-5-nitrophthalimides were produced via nucleophilic aromatic substitution (NAS) of 4,5-dichloro phthalimide substituents by potassium nitrite. The use of a N-phenyl-phthalimide having a protected 4′-hydroxyl group allows concurrent deprotection and nitro reduction to amine to give the 4-hydroxy-5-amino-N-(4′-hydroxyphenyl) phthalimide. This key intermediate is the precursor to a poly (ether-imide-benzoxazole), and is the condensable monomer for a poly (ester-imide-benzoxazole). Benzoxazole monomer formation via condensation with p-fluorobenzoyl chloride afforded 2-(4′-fluorophenyl)-5,6,-N-[4′(-hydroxyphenyl) imide]-benzoxazole, which was polymerized under NAS conditions to produce a poly(ether-imide-benzoxazole) having an endothermic transition at 454°C with weight retention of 90% at 500°C in both air and nitrogen. Solution polycondensation of the 4-hydroxy-5-amino-N-(4′-hydroxyphenyl) phthalimide monomer with isophthaloyl chloride afforded a poly(ester-amide-imide) which was isolated and thermally cyclodehydrated in the solid state under vacuum to give a poly(ester-imide-benzoxazole) having 95% weight retention at 500°C in both air and nitrogen, with no detectable DSC transitions up to 500°C. © 1994 John Wiley & Sons, Inc.     

Synthesis,structure, and properties of <Emphasis Type="Italic">N</Emphasis>-(nitramino)phthalimide

N-(Nitramino)phthalimide R₂N-NHNO₂ (R₂NH is phthalimide) was synthesized by nitration of N-aminophthalimide with nitronium tetrafluoroborate. The structure of this compound was established by X-ray diffraction and confirmed by ¹H, ¹³C, and ¹⁴N NMR spectroscopy. The methylation of this compound with diazomethane affords a mixture of N-methyl (R₂N-NMeNO₂) and O-methyl (R₂N-N=N(O)OMe) isomers. The latter compound contains the previously unknown high-nitrogen-oxygen fragment. The thermal decomposition of N-(nitramino)phthalimide in vacuo at 80–100 °C gives 2H-3,1-benzoxazine-2,4(1H)-dione (isatoic anhydride) as the major product. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 625–630, March, 2008.     

Amidomethylation of phenanthridines: Synthesis and structure determination by 1H NMR

Phenanthridine reacts with N-(hydroxymethyl)phthalimide to give, in two steps, three monosubstituted aminomethylphenanthridines. The three isomers were separated by chromatography on silica gel. The position of substitution was determined using one- and two-dimensional ¹H nmr methods.     

Thermochemical studies of phthalimide and two N-alkylsubstituted phthalimides (ALKYL=ETHYL AND n-PROPYL)

The standard (p⁰=0.1 MPa) molar enthalpies of formation, Δ_fH_m⁰, for crystalline phthalimides: phthalimide, N-ethylphthalimide and N-propylphthalimide were derived from the standard molar enthalpies of combustion, in oxygen, at the temperature 298.15 K, measured by static bomb-combustion calorimetry, as, respectively, – (318.0±1.7), – (350.1±2.7) and – (377.3±2.2) kJ mol^–1. The standard molar enthalpies of sublimation, Δ_cr^gH_m⁰, at T=298.15 K were derived by the Clausius-Clapeyron equation, from the temperature dependence of the vapour pressures for phthalimide, as (106.9±1.2) kJ mol^–1 and from high temperature Calvet microcalorimetry for phthalimide, N-ethylphthalimide and N-propylphthalimide as, respectively, (106.3±1.3), (91.0±1.2) and (98.2±1.4) kJ mol^–1. The derived standard molar enthalpies of formation, in the gaseous state, are analysed in terms of enthalpic increments and interpreted in terms of molecular structure.     

The kinetics and mechanism of alkaline hydrolysis of N-substituted phthalimides

The aqueous cleavage of N-(2-bromoethyl)phthalimide (NBEPH), N-(3-bromopropyl)phthalimide (NBPPH), and N-carbethoxyphthalimide (NCPH) have been studied within the [ōH] range of 5 × 10^?4 M to 2 × 10^?3 M, pH range of 8.82 to 10.62 and 8.06 to 8.66, respectively. The observed pseudo-first-order rate constants, k_obs, reveal a linear relationship with [ōH] with essentially zero intercept. The alkaline hydrolysis of N-(hydroxymethyl)phthalimide (NHMPH) has been studied within the [ōH] range of 5.64 × 10^?6 M to 2.0 M. The [OH]-rate profile reveals that both ionized and nonionized NHMPH are reactive toward ōH. The second-order rate constant, k_OH, for the reaction of ōH with non-ionized NHMPH is ca. 10⁴ times larger than that with ionized NHMPH. The values of k_OH obtained for NBEPH, NBPPH, NCPH, and nonionized NHMPH show a reasonable linear relationship with Taft substituent constants, and the slope (ρ*) of the plot is 1.01 ± 0.10. The low value of ρ* of 1.01 is attributed to nucleophilic attack as the rate-limiting. The k_OH value for ionized NHMPH reveals nearly 10³-fold negative deviation from the linear Taft plot.     

Synthesis and characterization of new soluble polyamides containing phthalimide pendent group

A dicarboxylic acid monomer, 5-phthalimidoisophthalic acid, containing a phthalimide pendent group was prepared by the condensation of 5-aminoisophthalic acid and phthalic anhydride in glacial acetic anhydride. The monomer was reacted with various aromatic diamines to produce polyamides using triphenyl phosphite and pyridine as condensing agents. These polyamides were produced with inherent viscosities of 0.64–1.14 dL · g⁻¹. All the polymers, characterized by wide-angle X-ray diffraction, revealed an amorphous nature resulting from the presence of the bulky pendent group. These polyamides exhibited excellent solubility in a variety of solvents such as N- methyl-2-pyrrolidinone, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, dimethyl sulfoxide, pyridine, and cyclohexanone. These polyamides showed glass-transition temperatures (T_g's) between 247 and 273 °C (by DSC) and 248 and 337 °C (by a dynamic mechanical analyzer). The thermogravimetric analytic measurement revealed the decomposition temperature at 10% weight-loss temperatures (Td₁₀) ranging from 442 to 530 °C in nitrogen. The polyamides containing phthalimide groups exhibited higher T_g and Td₁₀ values than those having no phthalimide groups. Transparent, tough, and flexible films of these polyamides could be cast from the DMAc solutions. These casting films had tensile strengths ranging from 81 to 126 MPa, elongations at break ranging from 7 to 13%, and tensile moduli ranging from 2.0 to 2.9 GPa. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1557–1563, 2001     

Induced Circular Dichroism and Magnetic Circular Dichroism Spectra of Maleimide and Related Molecules

The induced circular dichroism (ICD) spectra of the inclusion complexes of maleimide, phthalimide, and naphthalene‐2,3‐dicarboximide with β‐ or γ‐cyclodextrin (CDx) have been measured. The structure of the CDx inclusion complexes are interpreted by the signs and shapes of ICD spectra compared with the results of PPP calculations. In maleimide and naphthalene‐2,3‐dicarboximide, the ICD spectra of the β‐CDx inclusion complex are very similar to those of the γ‐CDx inclusion complex in spite of the differences in dimensions between the cavity of β‐CDx and that of γ‐CDx. In phthalimide, the ICD spectra of the β‐CDx inclusion complex are very different from those of the γ‐CDx inclusion complex. The split‐type ICD bands at 220–235 nm show that the dimer of phthalimide is formed in the presence of β‐CDx.     

A novel potent non‐nucleoside reverse transcriptase inhibitor acyl­thio­carbamate derivative with extensive intra­molecular π–π inter­actions

In the crystal structure of the novel acyl­thio­carbamate derivative O‐[2‐(1,3‐dioxo‐2,3‐dihydro‐1H‐isoindol‐2‐yl)­ethyl] N‐(4‐methyl­phenyl)‐N‐(3‐nitro­benzoyl)thio­carbamate, C₂₅H₁₉N₃O₆S, intra‐ and inter­molecular π–π inter­actions occur between the phthalimide and N‐benzoyl moieties. The partial atomic charges, calculated by ab initio methods, are consistent with the observed structure.