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

Abstract

Synopsis 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,"-(1,2-Ethanediyl)bis(4-nitrophthalimide) (15) and NW-(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-vinylpheny1)-4-nitrophthalimide (25d). Monomers 25a and 25b were polymerized by freeradicd 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 (BFrOEt2). Monomer 25b and styrene were copolymerized and their reactivity ratios were rl = 1.7 and r2 = 0.55, respectively. The prepared polymers are useful as backbone polymers for grafting living anionic polymers. EXPERIMENTALAll melting points were determined in open capillary tubes on a Thomas Hoover Capillary Melting Point Apparatus and are uncorrected. Elemental analyses were performed by Spang Laboratories, Eagle Harbor, Michigan, or by Galbraith Laboratories, Inc., Knoxville, Tennessee. All viscosity measurements were carried out at 25.0°C using Cannon-Ubbelohde Semi-Micro dilution viscometers. UV spectra were recorded on a Perkin-Elmer Model 402 spectrophotometer; IR spectra were recorded on a Perkin-Elmer Model 257 spectrophotometer. NMR spectra were recorded on a Varian T-60 and on a Jasper Electronic Optics Laboratories (JEOL) 100 MHz NMR spectrophotometer. All solvents were of high purity (99.9%) and distilled before use. All other reagents were used as received. N-(2-Hydroxyethyl)-4-Nitrophthalimide (2)4-Nitrophthalimide was prepared according to the literaturelo in 53% yield. The procedure described for the preparation of N-(2-hydroxyethy1)phthalimide in the patent literaturell was adopted here in the following manner. 4-Nitrophthalimide (95.5 g, 0.5 mol), 4-methyl-2-pentanone (300 mL, and chromium tris(2-ethylhexanoate) (1.0 g) were placed in a 1 L autoclave. The mixture was cooled in a dry ice bath and ethylene oxide (26.5 g, 0.6 mol) was added. The autoclave was closed and placed in the oil bath which was then heated to 160-165OC for 2 h. The reaction mixture was allowed to cool to room temperature overnight and the excess ethylene oxide was released.* The solvent was evaporated under reduced pressure and the yellow residue was crystallized from ethanol-acetone to give 112.0 g pale yellow crystals (95% yield) of pure N42hydroxyethyl)-4-nitrophthalimide; m.p. 112-114OC. ANAL. Calcd for CloHsN205: C, 50.85; H, 3.41; N, 11.86. Found C, 50.87; H, 3.42; N, 11.80. NM...

Grafting of living poly(ethylene oxide) onto polystyrene via aromatic nucleophilic displacement of activated nitro groups

“…Benzyl lithium or benzyl magnesium chloride were treated with an HMPA solution of 4-nitro-N-methylphthalimide (6a) or N,N'- (1,3-propanediyl)bis(4-nitrophthalimide) (6b). 9 No displacement of the nitro group could be detected even after two weeks. Instead, the only process observed was elec-tron transfer from the carbanion to the phthalimide residue.…”

“…Displacement of nitro groups with alkoxide as nucleophile is not without precedent16 and has proven successful in our systems. The reaction of sodium methoxide with the model compounds 6a and 6b in hexamethylphosphonamide (HMPA) gave N-methyl-4-methoxyphthalimide (8) and N,"- (1,3-propan-ediyl)bis(4-methoxyphthalimide) (9) in 82 and 87% yields, respectively. Compound 8 has previously been prepared in 74% yield using DMSO as a solvent at 60-70°C.…”