Toshio Kakurai

Effect of boron trifluoride-diethyl ether (BF3.OEt2= in the Diels-Alder reaction of quinoline- and isoquinoline-5,8-dione with unsymmetrical aliphatic dienes : theoretical study on the orientation of cycloadditions

The Diels–Alder reaction of quinoline- and isoquinoline-5,8-dione with piperylene or isoprene gave regioisomers of the substituted azaanthraquinones, while the Lewis acid catalyst boron trifluoride–diethyl ether showed a drastic effect on regioselectivity in the reactions with piperylene. The Frontier Molecular Orbital (FMO) theory (calculated by CNDO/2 method) was applied to explain the orientation of the catalysed regioselective cycloadditions, by considering secondary orbital interactions.

Anionic Graft Copolymerization of 2-Vinylpyridine by Metallated Polymer and Some Properties of Graft Copolymers

2-Vinylpyridine was grafted anionically by and onto lithiated poly(styrene-co-p-benzylstyrene)having known molecular weight (M.) and the narrow-molecu1ar weight distribution. The yield in each run was about 100%o. The results of the M. measurement and the turbidimetric titration showed that the graft copolymer was the only product. On the assumption that the number of the branches of the graft copolymer is nearly equal to (anion number/molecule) of metallated polymer, M. of the branches of graft copolymer was calculated. Graft copolymers having knewn chemical composition, known molecular structure and multi-branches could be synthesized by the above-mentioned method.The solubility and intrinsic viscositses ([T]) of graft copolymers depended on their molecular structure. [op] values of graft copolymers in benzene at 300C were smaller than those expected on the basis of their M. values. The intrinsic viscosities were affected mainly by M. of branches and M. of backbone, but hardly by the number of branches. The solubility of graft copolymers was higher than that of poly(2-vinylpyridine) and lower than that of poly(styrenecop-benzylstyrene) in a mixed solvent of 2-butanone and n-heptane. lt shows that backbone Segments protect the branch segments from precipitation. On graft copolymers having the same M. and the same chemical composition, the solubility of the graft copolymer having the higher M. of branches was lower than that of the graft copolymer having the smaller of branches.