203854-49-3Relevant articles and documents
Homologation of α-amino acids to β-amino acids: 9-Fluorenylmethyl chloroformate as a carboxyl group activating agent for the synthesis of Nα-protected aminoacyldiazomethanes
Kantharaju,Suresh Babu, Vommina V.
, p. 2152 - 2158 (2007/10/03)
An efficient and stereospecific homologation of urethane-protected α-amino acids to β-amino acids by Arndt-Eistert approach using an equimolar mixture of Fmoc-/Boc-/Z-α-amino acid and 9-fluorenylmethyl chloroformate for the acylation of diazomethane synth
Synthesis of Fmoc-/Boc-/Z-β-amino acids via Arndt-Eistert homologation of Fmoc-/Boc-/Z-α-amino acids employing BOP and PyBOP
Vasanthakumar,Babu, V. V. Suresh
, p. 1691 - 1695 (2007/10/03)
A simple and efficient protocol for Arndt-Eistert chain homologation of Fmoc-/Boc-/Z-α-amino acids using BOP or PyBOP as a coupling agent to the corresponding β-amino acids, synthesizing the key intermediate α-diazoketones as crystalline solids in good yield is described.
Synthesis of β-amino acids: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyl-uronium tetrafluoroborate (TBTU) for activation of Fmoc-/Boc-/Z-α-amino acids
Patil, Basanagoud S.,Vasanthakumar, Ganga-Ramu,Suresh Babu
, p. 3089 - 3096 (2007/10/03)
A new and efficient method for the homologation of urethane protected α-amino acids to its β-homomers by the Arndt-Eistert method using TBTU as a coupling agent is described. Several Fmoc-/Boc-/Z-protected α-amino diazoketone derivatives have been obtaine
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.
Preparation of N-Fmoc-Protected β2- and β3-Amino Acids and Their Use as Building Blocks for the Solid-Phase Synthesis of β-Peptides
Guichard, Gilles,Abele, Stefan,Seebach, Dieter
, p. 187 - 206 (2007/10/03)
N-Fmoc-Protected (Fmoc = (9H-fluoren-9-ylmethoxy)carbonyl) β-amino acids are required for an efficient synthesis of β-oligopeptides on solid support. Enantiomerically pure Fmoc-β3-amino acids (β3: side chain and NH2 at C(3)(=C(β))) were prepared from Fmoc-protected (S)- and (R)-α-amino acids with aliphatic, aromatic, and functionalized side chains, using the standard or an optimized Arndt-Eistert reaction sequence. Fmoc-β2-Amino acids (β2 side chain at C(2), NH2 at C(3)(=C(β))) configuration bearing the side chain of Ala, Val, Leu, and Phe were synthesized via the Evans' chiral auxiliary methodology. The target β3-heptapeptides 5-8, a β3- pentadecapeptide 9 and a β2-heptapeptide 10 were synthesized on a manual solid-phase synthesis apparatus using conventional solid-phase peptide synthesis procedures (Scheme 3). In the case of β3-peptides, two methods were used to anchor the first β-amino acid: esterification of the ortho-chlorotrityl chloride resin with the first Fmoc-β-amino acid 2 (Method I, Scheme 2) or acylation of the 4-(benzyloxy)benzyl alcohol resin (Wang resin) with the ketene intermediates from the Wolff rearrangement of amino-acid-derived diazo ketone 1 (Method II, Scheme 2). The former technique provided better results, as exemplified by the synthesis of the heptapeptides 5 and 6 (Table 2). The intermediate from the Wolff rearrangement of diazo ketones 1 was also used for sequential peptide-bond formation on solid support (synthesis of the tetrapeptides 11 and 12). The CD spectra of the β2- and β3-peptides 5, 9. and 10 show the typical pattern previously assigned to an (M) 31 helical secondary structure (Fig.). The most intense CD absorption was observed with the pentadecapeptide 9 (strong broad negative Cotton effect at ca. 213 nm); compared to the analogous heptapeptide 5, this corresponds to a 2.5 fold increase in the molar ellipticity per residue!
