Synthesis and characterization of asymmetric o- and m-nitrobenzoic acids with a 1,3-benzodioxole skeleton
作者:Masaya Suzuki、Yoshihiro Nishida、Yuya Ohguro、Yoshiko Miura、Akiko Tsuchida、Kazukiyo Kobayashi
DOI:10.1016/j.tetasy.2003.10.030
日期:2004.1
A symmetric o- and m-nitrobenzoic acids with a 1,3-benzodioxole skeleton have been synthesized and characterized. The synthesis involved nitration at either the C-5 or C-6 position of 2-tert-butyl-2-methyl-1,3-benzodioxole-4-carboxylate derived from catechol. These were then resolved with chiral solid-phased HPLC columns into each of enantiomers (>99% ee), which were characterized by circular dichroism. The (S)-enantiomers were also obtained by fractional crystallization of the precursor prior to the nitration. When applied as chiral derivation agents for alcohols and amines, m-nitrobenzoic acid showed notable ability to separate the enantiomers in both HPLC and NMR analyses. On the other hand, H-1 NMR and X-ray data of their ester and amide derivatives strongly suggested that the o-nitrobenzoic acid would serve as a fluorescent building block useful for the assembly of beta-peptide linkages with a defined conformation. (C) 2003 Elsevier Ltd. All rights reserved.