Gynocardin and cyclopentenylglycine in Rawsonia lucida

Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution

“…These data, not reported previously for the free amino acids, 10 are of interest for determination of epimeric composition of naturally occurring 2-(cyclopent-2Ј-enyl)glycine. 1,8,9 The diastereotopic H-5Ј protons and the olefinic protons H-2Ј and H-3Ј were assigned from NOESY spectra, using correlations to H-1Ј. The 13 C resonances were assigned from 1 H, 13 C-shift correlation experiments.…”

“…The (2S,1ЈR) isomer, either alone or together with the (2S,1ЈS) epimer, was shown to accumulate in several plant species, including Androsiphonia adenostegia, 1 Caloncoba echinata, 8 Hydnocarpus anthelminthica, 8 and Rawsonia lucida. 9 Because of the biological importance of 2-(cyclopent-2Ј-enyl)glycine, development of routes to enantiomerically pure stereoisomers of the amino acid has attracted considerable interest. Thus, four diastereomeric esters obtained by esterification of the N-acetylamino acid with (R)-2-acetylamino-2-phenylethanol were separated by chromatography and converted to pure stereoisomers of N-acetyl-2-(cyclopent-2Ј-enyl)glycine, the relative and absolute stereochemistry of which was elucidated by combined use of X-ray crystallography, CD spectroscopy, and chemical correlation with N-acetyl-2-cyclopentylglycines.…”

“…Recently, a fully stereoselective synthetic method leading to the (2S,1ЈS) isomer was described. 15,16 The (2S,1ЈR) isomer, although detected in plant isolates, 1,8,9 has not yet been characterized as a pure compound. The inhibitory activity of 2-(cyclopent-2Ј-enyl)glycine was reported to be associated with this stereoisomer.…”

Synthesis of epimers of L‐cyclopentenylglycine using enzymatic resolution

“…The (2S,1ЈR) isomer, either alone or together with the (2S,1ЈS) epimer, was shown to accumulate in several plant species, including Androsiphonia adenostegia, 1 Caloncoba echinata, 8 Hydnocarpus anthelminthica, 8 and Rawsonia lucida. 9 Because of the biological importance of 2-(cyclopent-2Јenyl)glycine, development of routes to enantiomerically pure stereoisomers of the amino acid has attracted considerable interest. Thus, four diastereomeric esters obtained by esterification of the N-acetylamino acid with (R)-2acetylamino-2-phenylethanol were separated by chromatography and converted to pure stereoisomers of N-acetyl-2-(cyclopent-2Ј-enyl)glycine, the relative and absolute stereochemistry of which was elucidated by combined use of X-ray crystallography, CD spectroscopy, and chemical correlation with N-acetyl-2-cyclopentylglycines.…”

“…Recently, a fully stereo-selective synthetic method leading to the (2S,1ЈS) isomer was described. 15,16 The (2S,1ЈR) isomer, although detected in plant isolates, 1,8,9 has not yet been characterized as a pure compound. The inhibitory activity of 2-(cyclopent-2Јenyl)glycine was reported to be associated with this stereoisomer.…”