Article PDF
References
D. J. Cram and D. Y. Sogah, J. Am. Chem. Soc., 107, 8301 (1985).
Y. Okamoto, K. Suzuki, K. Ohta, K. Hatada, and H. Yuki, J. Am. Chem. Soc., 101, 4763 (1979).
Y. Okamoto, E. Yashima, T. Nakano, and K. Hatada, Chem. Lett., 1987, 759 (1987).
Y. Okamoto, K. Suzuki, and H. Yuki, unpublished data. In the polymerization of these monomers with the Sp-BuLi complex in toluene at −78°C, the isotacticity of the obtained polymers was low, and a highly isotactic poly(1,1-diphenylmethyl methacrylate) was obtained by using Sp-cyclohexylmagnesium bromide complex. However, the [α]D25 of these polymers was less than two degree.
GPC separation was performed on a GPC column (maximum porosity 3000) using chloroform as eluent.
The separation was performed on a silica gel column (Develosil 100-5, 50×0.72 (i.d.) cm) using an acetonitrile-butyl chloride mixture (5:95–50:50) as an eluent under gradient conditions. [ G. D. Andrews and A. Vatvars, Macromolecules, 14, 1603 (1981)].
Optical resolution was carried out on a cellulose tris(3,5-dimethylphenylcarbamate) column (25×0.46 (i.d.) cm) using a hexane-ethanol mixture as an eluent [ Y. Okamoto, M. Kawashima, and K. Hatada, J. Chromatogr., 363, 173 (1986)].
FD mass spectrum was taken on a JNM-DX303HF spectrometer.
K. Hatada, K. Ute, K. Tanaka, M. Imanari, and N. Fujii, Polym. J., 19, 425 (1987).
Polymerization was carried out at [MMA]/[1-NpMgBr]=20 (MÌ… n=3,800, MÌ… w/MÌ… n=1.65).
The m and r assignment of ω-end dyad is opposite to that reported in ref 9. The present assignment is supported by X-ray analysis of mm trimer [K. Hatada, K. Ute, T. Kitayama, K. Tanaka, M. Imanari, and N. Fujii, Polym. J., to be submitted;
K. Ute, T. Nishimura, K. Hatada, and Y. Matsuura, Polym. J., 21, (1989) in press.]
Values of specific rotation were estimated from the chromatograms shown in Figure 4. Concentration of the sample was calculated from the weight of the sample injected and the volume of the HPLC flow cell (length 5 cm, diameter 0.20 cm). The amounts of racemic samples were 2.1 mg for 5-mer and 2.0 mg for 8-mer.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Okamoto, Y., Nakano, T. & Hatada, K. Optical Activity of Isotactic Oligomers of Methyl Methacrylate. Polym J 21, 199–201 (1989). https://doi.org/10.1295/polymj.21.199
Issue Date:
DOI: https://doi.org/10.1295/polymj.21.199