1. Synthesis and Neuroprotective Action of Optically Pure Neoechinulin A and Its Analogs
- Author
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Toshiaki Aoki, Kensuke Ohnishi, Masaaki Kimoto, Satoshi Fujieda, Kouji Kuramochi, Toshifumi Takeuchi, Atsuo Nakazaki, Nobuo Watanabe, Fumio Sugawara, Takao Arai, and Susumu Kobayashi
- Subjects
neoechinulin A ,intramolecular cyclization ,cytoprotective activity ,Medicine ,Pharmacy and materia medica ,RS1-441 - Abstract
We developed an efficient, stereoselective synthetic method for the diketopiperazine moiety of neoechinulin A and its derivatives. The intramolecular cyclization at 80 ºC proceeded with minimal racemization of the stereogenic center at C-12 on neoechinulin A, even though the cyclization at 110 ºC caused partial racemization. In contrast with these results, the cyclization on diketopiperazine of 8,9-dihydroneoechinulin A derivatives did not cause epimerization of the stereogenic centers, even at 110 °C. We examined the structure-activity relationships for the cytoprotective activity against cytotoxicity induced by 3-morpholinosydnonimine (SIN-1) in nerve growth factor (NGF)-differentiated PC12 cells. The C-8/C-9 double bond, but not the stereogenic center derived from alanine, was found to play a key role in the cytoprotective activity.
- Published
- 2010
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