Jun Li, J. Uzawa, Y. Doi
Jul 15, 1998
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0
Influential Citations
11
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
Oligomers of (R)-3-hydroxybutanoic acid (3-HB) with different end groups and chain lengths have been prepared as model compounds of bacterial poly[(R)-3-hydroxybutanoate] [P(3-HB)]. They were studied in terms of their conformational behavior generated by rotation about CH2–CH bond of 3-HB units in solutions. The conformational behaviors of 3-HB oligomers were investigated in various solvents by analysis of vicinal coupling in the 500-MHz 1H NMR spectra. For all 3-HB oligomers studied in this work, 3-HB units without hydroxy group were found, in every solvent, to adopt similar conformational distributions to those of P(3-HB) polymer backbone in solutions, in which trans and gauche conformers are preferable, while the other gauche conformer is strongly disfavored. On the other hand, 3-HB units adjacent to hydroxy terminal group in 3-HB oligomers show different conformational behaviors relative to those of other 3-HB units. In non-polar organic solvents, only gauche conformer is predominant, due to the forma...