201864-70-2Relevant articles and documents
A one-pot procedure for the preparation of N-9-fluorenylmethyloxycarbonyl- α-amino diazoketones from α-amino acids
Siciliano, Carlo,De Marco, Rosaria,Guidi, Ludovica Evelin,Spinella, Mariagiovanna,Liguori, Angelo
, p. 10575 - 10582 (2013/02/22)
The study describes a new "one-pot" route to the synthesis of N-9-fluorenylmethyloxycarbonyl (Fmoc) α-amino diazoketones. The procedure was tested on a series of commercially available free or side-chain protected α-amino acids employed as precursors. The conversion into the title compounds was achieved by masking and activating the α-amino acids with a single reagent, namely, 9-fluorenylmethyl chloroformate (Fmoc-Cl). The resulting N-protected mixed anhydrides were reacted with diazomethane to lead to the α-amino diazoketones, which were isolated by flash column chromatography in very good to excellent overall yields. The versatility of the procedure was verified on lipophilic α-amino acids and further demonstrated by the preparation of N-Fmoc-α-amino diazoketones also from α-amino acids containing side-chain masking groups, which are orthogonal to the Fmoc one. The results confirmed that tert-butyloxycarbonyl (Boc), tert-butyl (tBu), and 2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl (Pbf), three acid-labile protecting groups mostly adopted in the solution and solid-phase peptide synthesis, are compatible to the adopted reaction conditions. In all cases, the formation of the corresponding C-methyl ester of the starting amino acid was not observed. Moreover, the proposed method respects the chirality of the starting α-amino acids. No racemization occurred when the procedure was applied to the synthesis of the respective N-Fmoc-protected α-amino diazoketones from l-isoleucine and l-threonine and to the preparation of a diastereomeric pair of N-Fmoc-protected dipeptidyl diazoketones.
Efficient and direct solid phase synthesis of ketomethylenimino and ketomethylenamino peptides
Bernard, Elise,Vanderesse, Régis
, p. 8603 - 8606 (2007/10/03)
The reaction between the free amino terminus of a solid-supported peptide and a glyoxal leads to two families of pseudopeptides, the ketomethylenimino and the ketomethylenamino peptides. The aim of this study is the synthesis of pseudopeptides on solid supports, in order to quickly obtain modified peptides. We report a convenient step-by-step synthesis of ketomethylenimino ψ[CO-CH=N] and ketomethylenamino ψ[CO-CH2-NH] peptides. The key is the reaction between the free amino terminus of the supported peptide and a glyoxal-modified amino acid, leading to a ketomethylenimino bond, which can be reduced to a ketomethylenamino bond.
Convenient and simple homologation of Nα-urethane protected α-amino acids to their β-homologues with concomitant o-nitrophenylesters formation
Ananda,Gopi,Suresh Babu
, p. 790 - 795 (2007/10/03)
The Wolff rearrangement of α-aminodiazoketones derived from Nα-urethane protected α-amino acids in presence of o-nitrophenol catalyzed by silver acetate at low temperature is described. The potential utility of the well-known ketene intermediat
Convenient and simple synthesis of N-{[(9H-fluoren-9- yl)methoxy]carbonyl}-(Fmoc) protected β-amino acids (=homo-α-amino acids) employing Fmoc-α-amino acids and dicyclohexylcarbodiimide(DCC) mixtures
Ananda,Suresh Babu
, p. 418 - 423 (2007/10/03)
A simple approach for the homologation of α-amino acids to β-amino acids by the Arndt-Eistert method employing Fmoc-α-amino acid and N, N1- dicyclohexylcarbodiimide (DCC) mixture for the acylation of diazomethane, synthesizing the key intermediates Fmoc-α-amino acyldiazomethanes as crystalline solids is described.
Synthesis of N-{[(9H-Fluoren-9-yl)methoxy]carbonyl}-Protected (Fmoc) β-Amino Acids (= Homo-α-Amino Acids) by Direct Homologation
Ellmerer-Mueller, Ernst P.,Broessner, Dagmar,Maslouh, Najib,Tako, Andreas
, p. 59 - 65 (2007/10/03)
The successful application of the Arndt-Eistert protocol starting from commercially available N-{[(9H-fluoren-9-yl)methoxy]carbonyl}-protected (Fmoc) α-amino acids leading to enantiomerically pure N-Fmoc-Protected β-amino acids in only two steps and with high yield is reported.
