Axially chiral bis(α-amino acid)s and dioxopiperazines. Synthesis and configurational assignment
1999; Elsevier BV; Volume: 55; Issue: 42 Linguagem: Inglês
10.1016/s0040-4020(99)00717-6
ISSN1464-5416
AutoresLuděk Ridvan, Miloš Buděšı́nský, Miloš Tichý, Petr Maloň, Jiřı́ Závada, Jaroslav Podlaha, Ivana Cı́sařová,
Tópico(s)Chemical Synthesis and Analysis
ResumoAbstract Conversion of the easily accessible racemic bis(amino acid)s cis- and trans-2a into the (S)-enantiomers via the corresponding Schiff bases with (1S,2S,5S)-2-hydroxy-3-pinanone is described. Condensation of the N-Boc-protected bis(amino acid)s with esters of the corresponding axially chiral amino acids (R)- and (S)- 1b afforded tetraspiro-substituted bis(dioxopiperazine)s 7 representing a rare case of primary helical topology. Absolute configuration of the products was assigned by NMR and CD spectra and confirmed by X-ray analysis of the Schiff base (S)-cis- 3 .
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