N-benzyloxycarbonyl -protected

Unsymmetrical N-benzyloxycarbonyl-protected 1-amino-1 -arylalkylphos-phonate mixed esters have been synthesized using a one-pot reaction of benzyl carbamate aromatic aldehydes and alkoxydichlorophosphine followed by... 

Knudsen, K.R.. Holden. J.. Ley. S.V.. and Ladlow, M. (2007) Optimisation of conditions for O-benzyl and N-benzyloxycarbonyl protecting group removal using an automated flow... 

In order to test the influence of the C-terminus protecting groups on the properties of the resulting polymer, the ethyl, hexyl, and palmityl esters of N-benzyloxycarbonyl-L-tyrosyl-L-tyrosine were synthesized and the corresponding polymers (poly(CTTE),... 

In a synthesis of the L-serine derivative 133, Kunz and Buchholz100 treated N-(benzyloxycarbonyl)-L-serine 2-bromoethyl ester (135) with tetra-O-benzoyl-a-D-glucopyranosyl bromide (136) protection of the... 

Synthesis of N-Protected a-Amino Acids from N-(Benzyloxycarbonyl)-L-Serine via Its g-Lactone N -(Benzyloxycarbonyl)-p-(Pyrazol-1-yl)-L-Alanine... 

Alternatively, oxazolones have been used as reagents to activate and to couple N-protected dicarboxylic amino acids wherein the carboxylate moiety acts as the nucleophile. For example, 2,4-dimethyl-5(4//)-oxazolone 255 reacts with N-benzyloxycarbonyl-L-aspartic acid to give a mixture of the anhydrides 256 and 257. Subsequent reaction of 256 and 257 with phenylalanine methyl ester hydrochloride and A-methylmorpholine produces a mixture of the a-isomer 258 and p-isomer 259 of Al-benzyloxycarbonyl-aspartylphenylalanine methyl ester (Scheme 7.83). °... 

The racemic mixture of Z-Gly-DL-Alap can be separated to give pure enantiomers by simple crystallization with enantiomeric a-methylbenzylaminesJ7] An example of the separation of enantiomers is given in Scheme 5 for the separation of Z-L-Ala-D-Ala and Z-L-Ala-D-Ala.[7] The N-terminal protecting benzyloxycarbonyl group is removed by standard hydrogenolysis on 5% Pd/C catalyst. 

To add a leucine residue to the N terminus of the ethyl ester of Z-Phe-Gly, the benzyloxycarbonyl protecting group must first be removed. This can be accomplished by hydrogenolysis. 

Although CDI was applied as early as 1972 as reagent for the esterification of starch and dextran, it has only scarcely been used up to now. Its renaissance during the last few years may be due to the fact that it became an affordable commercially available product. Among the first attempts for the esterification of polysaccharides via CDI is the binding of amino acids onto dextran. Besides CDI, -(thiocarbony diimidazole can be utilised to obtain the corresponding imidazolide [198]. The amino acids bound via this path are glycine, L-leucine, L-phenylalanine, L-histidine and L-alanyl-L-histidine. They are protected with N-trifluoroacetyl, N-benzyloxycarbonyl... 

Derivatives of threonine have also been used as chiral building blocks in natural product synthesis, For example, a synthesis of the rare monosaccharide Callipel-lose [Scheme 3.125] began with the N-benzyloxycarbonyl derivative of D-threo-nine methyl ester (125.1).243 Simultaneous protection of the amino and hydroxyl... 

Protecting group abbreviations are as follows N-benzyloxycarbonyl (Z), N-lert-butyloxycarbonyl (Boc), (ert-butyl ether (Bu ), and S-leit-butyl (Bu ). 

Since the use of N,N-dimethylacetamide and triethylamine improved the rate and extent of cleavage of the N-benzyloxycarbonyl group m several difficult cases, these additives have been incorporated into the submitters standard procedure and are included in the present procedures. Deprotection with this method has been carried out with as much as 25 g. of the protected peptide. 

---