Rapid and efficient synthesis of peptide fragments containing α- aminoisobutyric acid using Fmoc-amino acid chlorides/potassium salt of 1- hydroxybenzotriazole

The synthesis of peptides containing multiple Aib residues was accomplished using Fmoc-Aib-Cl in presence of KOBt. As no additional base was added, the duration of coupling reactions could be extended. Thus, the synthesis of the alamethicin 1-4 fragment, Aib-Pro-Aib-Ala, the emerimicin 2- 6 fragment, Aib-Aib-Aib-Val-Gly and the Aib tetramer, Fmoc-(Aib)4-OBzl were accomplished in good yield and purity

Synthesis of peptides employing Fmoc-amino acid chlorides and commercial zinc dust

Coupling of Fmoc-amino acid chlorides mediated by activated commercial zinc dust for the synthesis of peptides is described. The reaction is carried out in an organic medium. The necessity of using an inorganic base like NaHCO3/Na2CO3 or an organic base like DIEA/NMM/TEA/pyridine is circumvented. The coupling is reasonably fast, clean, racemization free and high yielding

Homologation of alpha-amino acids to beta-amino acids using Fmoc-amino acid pentafluorophenyl esters

The homologation of alpha-amino acids to beta-amino acids by the two-step Arndt-Eister method is achieved by using Fmoc-alpha-amino acid pentafluorophenyl esters for the acylation of diazomethane, synthesizing the key intermediates Fmoc-aminoacyldiazomethanes as crystalline solids in good yields and purity

ChemInform Abstract: Synthesis of Boc‐ and Z‐Protected Amino Acid Fluorides Employing DAST as a Fluorinating Agent.

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Synthesis of β-amino acids using Boc-/Z-amino acid pentafluorophenyl esters

The pentafluorophenyl esters of Boc-/Z-amino acids are used for the preparation of the key intermediates α-aminoacyldiazomethanes during the homologation of α-amino acid to α-amino acid. Thus, all the Boc-/Z-amino acid diazoketones and the corresponding β-amino acids were obtained as crystalline solids in satisfactory yields. © 1999 Kluwer Academic Publishers

Synthesis of [Leu5]​enkephalin using Fmoc-​amino acid chloride​/KOAt

The coupling of Fmoc-​amino acid chlorides can be mediated by the potassium salt of 1-​hydroxy-​7-​azabenzotriazole. Thus the synthesis of [Leu5]​enkephalin has been accomplished in good yield and purity

Convenient and simple homologation of N(α)-urethane protected α-amino acids to their β-homologous with concomitant pentafluorophenyl ester formation

The Wolff rearrangement of α-aminodiazoketones derived from N(α)-urethane protected α-amino acids in the presence of pentafluorophenol catalyzed by silver acetate at low temperature results in the homologation of Fmoc-/Boc-/Z-α-amino acids to β-amino acids with concomitant formation of the corresponding pentafluorophenyl esters in good yield and purity

Zinc-promoted simple synthesis of oligomer-free N(α)-Fmoc-amino acids using Fmoc-Cl as an acylating agent under neutral conditions

A range of N(α)-Fmoc-protected amino acids, including those that contain t-butyl moiety, have been synthesized by employing Fmoc-Cl utilizing the activated, commercial zinc dust-promoted synthesis of carbamates under neutral conditions. A general procedure is described that circumvents the oligomerization side reaction normally noticed in Schotten-Baumann conditions. It is a simple, convenient and clean method. Thus, Fmoc-amino acids are obtained in high yield (85-92) and purity as checked by thin-layer chromatography, high-performance liquid chromatography and other physical methods

Zinc promoted simple synthesis of Z-amino acids under neutral conditions

The introduction of benzyloxylcarbonyl (Z) group into amino acids is described at neutral pH using benzyloxylcarbonyl chloride and activated zinc powder. The reaction is simple, fast and clean. Thus the Z-amino acids are prepared in good yield and purity

Rapid and efficient synthesis of peptides containing α,α-dialkylamino acids employing KOBt

Several Fmoc-α,α-dialkylamino acids and their acid chlorides have been prepared, isolated and characterised. The synthesis of peptides containing sterically hindered dialkylamino acids has been accomplished using acid chloride/KOBt in dichloromethane. The yields as well as the purity of the peptides were satisfactory. © 1998 Kluwer Academic Publishers