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Titolo:
TOTAL SYNTHESIS OF BOUVARDIN, O-METHYLBOUVARDIN, AND O-METHYL-N-9-DESMETHYLBOUVARDIN
Autore:
BOGER DL; PATANE MA; ZHOU JC;
Indirizzi:
SCRIPPS CLIN & RES INST,DEPT CHEM,10666 N TORREY PINES RD LA JOLLA CA92037
Titolo Testata:
Journal of the American Chemical Society
fascicolo: 19, volume: 116, anno: 1994,
pagine: 8544 - 8556
SICI:
0002-7863(1994)116:19<8544:TSOBOA>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANTITUMOR CYCLIC HEXAPEPTIDES; CATALYZED ASYMMETRIC DIHYDROXYLATION; ULLMANN MACROCYCLIZATION REACTION; SUBUNIT FUNCTIONAL ROLES; RA-VII; RUBIAE RADIX; CONFORMATIONAL-ANALYSIS; BICYCLIC HEXAPEPTIDES; ENANTIOMERIC PURITY; KINETIC RESOLUTION;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
106
Recensione:
Indirizzi per estratti:
Citazione:
D.L. Boger et al., "TOTAL SYNTHESIS OF BOUVARDIN, O-METHYLBOUVARDIN, AND O-METHYL-N-9-DESMETHYLBOUVARDIN", Journal of the American Chemical Society, 116(19), 1994, pp. 8544-8556

Abstract

Concise total syntheses of bouvardin (1) and O-methylbouvardin (2) are described based on the asymmetric synthesis of the -methyl-erythro-beta-hydroxy-L-4-iodophenylalanine derivative 24, its coupling with theselectively protected N,O-4-dimethyl-L-DOPA methyl ester to provide 40, and subsequent incorporation into a surprisingly successful key Ullmann macrocyclization reaction for preparation of the 14-membered 13 (S)-hydroxycycloisodityrosine subunit 15 of the bicyclic hexapeptides. Coupling of 15 with BOCNH-D-Ala-Ala-NMe-Tyr(OMe)-Ala-OC6F5 followed by18-membered-ring macrocyclization strategically conducted with formation of a secondary amide at a D-amino acid amine terminus (C-2-N-3 amide) provided O-methylbouvardin (2). Selective demethylation (BBr3) of 2 provided bouvardin (1) in excellent conversion (86%). The extensionsof the studies to the preparation of O-methyl-N-9-desmethylbouvardin (51) are detailed and its solution-phase conformational properties examined by H-1 NMR in efforts which confirm that the additional minor conformation of 1 and 2 (ca. 10-15%) observed in nonpolar solvents (CDCl3, THF-d(8)), arise from a cis N-9-C-8 N-methylamide conformation.

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Documento generato il 23/09/20 alle ore 20:52:27