title: "One-pot" methylation of N-Nosyl-alpha-amino acid methyl esters with diazomethane and their coupling to prepare N-methyl dipeptides.
abstract: 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.
authors.affiliation: 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.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Di Gioia
authors.forename: Antonella
authors.initials: A
authors.lastname: Leggio
authors.forename: Adolfo
authors.initials: A
authors.lastname: Le Pera
authors.forename: Angelo
authors.initials: A
authors.lastname: Liguori
authors.forename: Anna
authors.initials: A
authors.lastname: Napoli
authors.forename: Carlo
authors.initials: C
authors.lastname: Siciliano
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sindona
mesh_terms: 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
chemical_list: D000596:Amino Acids; D004151:Dipeptides; D004952:Esters; D003978:Diazomethane