Asymmetric 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, 1H 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 β-peptide linkages with a defined conformation.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry