"One-pot" methylation of N-Nosyl-alpha-amino acid methyl esters with diazomethane and their coupling to prepare N-methyl dipeptides.
N-Nosyl-alpha-amino acid methyl esters are methylated quantitatively with diazomethane. After proper deprotection of the amino function by treatment with the reagent system mercaptoacetic acid/sodium methoxide, the obtained N-methyl amino acid methyl esters are coupled with N-Fmoc amino acid chlorides to afford the corresponding dipeptides. The obtained products do not show any detectable extent of racemization by (1)H NMR and HPLC.
Di Gioia
Maria Luisa
ML
Dipartimento di Scienze Farmaceutiche and Dipartimento di Chimica, Università degli Studi della Calabria, Via Ponte P. Bucci, Cubo 15/C, I-87036 Arcavacata di Rende (CS), Italy.
Leggio
Antonella
A
Le Pera
Adolfo
A
Liguori
Angelo
A
Napoli
Anna
A
Siciliano
Carlo
C
Sindona
Giovanni
G
D000596:Amino Acids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003978:Diazomethane; D004151:Dipeptides / Q000138:chemical synthesis* / Q000302:isolation & purification; D004952:Esters / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D013237:Stereoisomerism
D000596:Amino Acids; D004151:Dipeptides; D004952:Esters; D003978:Diazomethane