Radical polymerization of 2,5‐norbornadienes containing ester groups by AIBN and oxygen gas

Abstract

New 2,5‐norbornadiene‐type monomers bearing 1‐adamantyl and cyclohexyl ester groups on their 2‐position polymerized with azobisisobutyronitrile to form the polymers consisting of two types of polymer unit structures. The major part had a saturated nortricyclene framework, which was formed by 2,6‐addition along with intramolecular cyclization on the norbornadiene moiety. The minor part consisted of 2‐norbornene‐type units constructed via 2,3‐addition. A series of norbornadiene‐based monomers spontaneously polymerized in the presence of oxygen. Because a radical inhibitor, namely hydroquinone, could suppress this spontaneous reaction, it was indicated that the oxygen‐induced polymerization proceeds via free‐radical polymerization mechanism. Changing a quantity of provided oxygen gas (O2) to a norbornadiene monomer significantly affected on polymerization results, in specific, molecular weight of the formed polymer, which indicated that oxygen serves as one of the key reagents for the formation of free‐radical initiating species. It was proven that the combination of norbornadiene ethyl ester with O2 was applicable as a new free‐radical initiator for polymerization of methyl methacrylate. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2528–2536

Synthesis of 2,3-Dihydro-4-pyridones and 4-Pyridones by the Cyclization Reaction of Ester-Tethered Enaminones

“…After filtration, the solvent was evaporated under reduced pressure and the residue was purified by column chromatography on silica gel using PE (bp 40–60 °C)/EtOAc (100:0 to 95:5) to give 287.0 mg (75%) of the ester as a colourless liquid. IR: ν 3263, 2118, 1711, 1235 cm –1 ; 1 H NMR (500.3 MHz, CDCl 3 ): δ 4.84–4.89 (m, 1H), 2.85 (s, 1H), 1.87–1.91 (m, 2H), 1.73–1.78 (m, 2H), 1.22–1.56 (m, 6H); 13 C­{ 1 H} NMR (125.8 MHz, CDCl 3 ): δ 152.2, 75.3, 75.2, 73.9, 31.3, 25.1, 23.6.…”

Silica Gel as a Promoter of Sequential Aza‐Michael/Michael Reactions of Amines and Propiolic Esters: Solvent‐ and Metal‐Free Synthesis of Polyfunctionalized Conjugated Dienes

“…40–60 °C)/EtOAc; 100:0–95:5) to give 2 e as a colorless liquid (yield: 287.0 mg, 75 %). 1 H NMR (500.3 MHz, CDCl 3 ): δ =1.22–1.56 (m, 6 H), 1.73–1.78 (m, 2 H), 1.87–1.91 (m, 2 H), 2.85 (s, 1 H), 4.84–4.89 ppm (m, 1 H); 13 C NMR (125.8 MHz, CDCl 3 ): δ =23.6, 25.1, 31.3, 73.9, 75.2, 75.3, 152.2 ppm; IR: =3263, 2118, 1711, 1235 cm −1 .…”

“…40-60 8C)/EtOAc; 100:0-95:5) to give 2e as ac olorless liquid (yield:2 87.0 mg, 75 %). 1 HNMR (500.3 MHz, CDCl 3 ): [33] Phenylpropiolate (2 f) Phenyl propiolate (2f)w as obtained according to the procedure given for the synthesis of aryl alkynoate esters. [34] As olution of DCC (N,N'-dicyclohexylcarbodiimide) (520.0 mg, 2.5 mmol) in CH 2 Cl 2 (2 mL) was added to as olution of propiolic acid (197.0 mg, 2.8 mmol) in CH 2 Cl 2 (2 mL) at 0 8C.…”

Synthesis and Characterization of a High-Temperature Thermoset Network Derived from a Multicyclic Cage Compound Functionalized with Exocyclic Allylidene Groups

“…This is despite the extensive investigation of the polymerization chemistry of multicyclic compounds, such as norbornene, norbornadiene, and dicyclopentadiene (Scheme ). − In general, polymers of these simple unsaturated species exhibit high T g values, good mechanical strength, and high thermal stability, leading to their utility in a variety of aerospace and industrial applications . In contrast, polymers based on the adamantane core have only been sparsely investigated since 1960.…”

“…Heptacyclo[6.6.0.0 2,6 .0 3,13 .0 4,11 .0 5,9 .0 10,14 ]tetradecanes (HCTD) represent a unique class of cage molecules with highly symmetrical structures. 1 Similar to the multicyclic cubanes (four-membered rings) and adamantanes (six-membered rings), HCTD species are a distinct repository of fused five-membered carbocyclic rings (Scheme 1).…”