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Titolo:
X-RAY CRYSTAL-STRUCTURE OF WOODININE AND CONFORMATIONAL-ANALYSIS BY SEMIEMPIRICAL AND H-1-NMR METHODS
Autore:
MAHBOOBI S; DOVE S; BEDNARSKI PJ; KUHR S; BURGEMEISTER T; SCHOLLMEYER D;
Indirizzi:
UNIV REGENSBURG,DEPT PHARMACEUT CHEM D-93040 REGENSBURG GERMANY UNIV REGENSBURG,DEPT ORGAN CHEM D-93040 REGENSBURG GERMANY UNIV MAINZ,DEPT ORGAN CHEM D-55099 MAINZ GERMANY
Titolo Testata:
Journal of natural products
fascicolo: 6, volume: 60, anno: 1997,
pagine: 587 - 591
SICI:
0163-3864(1997)60:6<587:XCOWAC>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
ASCIDIAN RITTERELLA-SIGILLINOIDES; EUDISTOMIN-K;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
17
Recensione:
Indirizzi per estratti:
Citazione:
S. Mahboobi et al., "X-RAY CRYSTAL-STRUCTURE OF WOODININE AND CONFORMATIONAL-ANALYSIS BY SEMIEMPIRICAL AND H-1-NMR METHODS", Journal of natural products, 60(6), 1997, pp. 587-591

Abstract

The molecular structure of (-)-woodinine (1), a carboline-based alkaloid with antibacterial and antimycobacterial activities, was investigated by X-ray crystallographic, NMR, and semiempirical quantum chemicalmethods. Compound 1 was prepared by reacting 5-bromotryptamine and (tert-butoxycarbonyl)pyrrolidine-2-carboxyaldehyde in a Pictet-Spengler-type reaction. The debrominated analogue of 1 was methylated at the indole nitrogen with methyl methane sulfonate after deprotonation with n-BuLi. The X-ray crystal structure of 1 showed the indole ring in the expected planar conformation, the pyrrolidine ring in an envelope conformation, and a weak intramolecular hydrogen bond between the pyrrolidine nitrogen and the proton of the indole nitrogen. NMR experiments indicated that this hydrogen bond is not present in solution and that further differences exist between the crystal and the solution structures of 1. By semiempirical quantum chemical methods, different local energy minimum conformations of 1, resulting from inversions within the piperideine moiety and from rotation of the pyrrolidine ring, were calculated. The totality of all NOE signals can only be explained to originate from a population of some of these conformers, and additionally from different envelope and twisted conformations of the pyrrolidine ring.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/10/20 alle ore 08:55:10