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Removal of the BOC group in amino acids can be accomplished with strong acids such as trifluoroacetic acid in dichloromethane, or with HCl in methanol. [2] [3] [4] A complication may be the tendency of the t-butyl cation intermediate to alkylate other nucleophiles; scavengers such as anisole or thioanisole may be used.
The Boc group can later be removed from the amine using moderately strong acids (e.g., trifluoroacetic acid). Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an ...
A very spectacular example application of protecting groups from natural product synthesis is the 1994 total synthesis of palytoxin acid by Yoshito Kishi's research group. [108] Here 42 functional groups (39 hydroxyls, one diol, an amine group, and a carboxylic acid) required protection.
Fmoc/tBu SPPS is less atom-economical, as the fluorenyl group is much larger than the Boc group. Accordingly, prices for Fmoc amino acids were high until the large-scale piloting of one of the first synthesized peptide drugs, enfuvirtide, began in the 1990s, when market demand adjusted the relative prices of Fmoc- vs Boc- amino acids.
In proteinogenic amino acids, it bears the amine and the R group or side chain specific to each amino acid, as well as a hydrogen atom. With the exception of glycine, for which the side chain is also a hydrogen atom, the α–carbon is stereogenic.
The fluorenylmethoxycarbonyl protecting group (Fmoc) is a base-labile amine protecting group used in organic synthesis, particularly in peptide synthesis. [1] It is popular for its stability toward acids and hydrolysis and its selective removal by weak bases, such as piperidine , without affecting most other protecting groups or sensitive ...
Di-tert-butyl-iminodicarboxylate is an organic compound that can be described with the formula [(CH 3) 3 COC(O)] 2 NH.It is a white solid that is soluble in organic solvents. The compound is used as a reagent for the preparation of primary amines from alkyl halides
Glycine N-carboxyanhydride is the parent member of the amino acid N-carboxyanhydrides.. NCAs are typically prepared by phosgenation of amino acids: [4]. They were first synthesized by Hermann Leuchs by heating an N-ethoxycarbonyl or N-methoxycarbonyl amino acid chloride in a vacuum at 50-70 °C: [5] [6]