Tert-Butyloxycarbonyl -protected

It has been found that the tris(tert-butyloxycarbonyl) protected hydantoin of 4-piperidone 2, selectively hydrolyses in alkali to yield the N-tert-butyloxycarbonylated piperidine amino acid 3. The hydrolysis, which is performed in a biphasic mixture of THF and 2.0M KOH at room temperature, cleanly partitions the deprotonated 4-amino-N -(tert-butyloxycarbonyl)piperidine-4-carboxylic acid into the aqueous phase of the reaction with minimal contamination of the hydrolysis product, di-tert-butyl iminodicarboxylate, which partitions into the THF layer. Upon neutralization of the aqueous phase with aqueous hydrochloric acid, the zwitterion of the amino acid is isolated. The Bolin procedure to introduce the 9-fluorenylmethyloxycarbonyl protecting group efficiently produces 4.8 This synthesis is a significant improvement over the previously described method9 where the final protection step was complicated by contamination of the hydrolysis side-product, di-tert-butyl iminodicarboxylate, which is very difficult to separate from 4, even by chromatographic means. 

Rich DH, Gurwara SK. Preparation of a new o-nitrobenzyl resin for solid-phase synthesis of tert-butyloxycarbonyl-protected peptide acids. J Am Chem Soc 1975 97 1575-1579. 

RE Reid. Solid phase peptide synthesis. A study on the effect of trifluoroacetic acid concentration on the removal of the tert-butyloxycarbonyl protecting group. J Org Chem 41, 1027, 1976. 

L Moroder, A Hallett, E Wiinsch, O Keller, G Wersin. di-tert-Butyldicarbonat — an advantageous reagent for introduction of the tert-butyloxycarbonyl protecting group. Hoppe-Seyler s Z Physiol Chem 357, 1651, 1976. 

The amide phase systems are also applicable to preparative scale separations. A semi-preparative bonded column (10 mm i.d. X 25 cm) was prepared, yielding a loading capacity of ca. 1 mg per 1 g packing material. Enantiomeric and diastereomeric pairs of benzyloxycarbonyl and tert-butyloxycarbonyl protected di- and tri-peptides were resolved successfully using this chiral amide-bonded column system. 

N-tert-Butyloxycarbonyl-Protected 2-Bromo-4-(trifluoromethoxy)aniline ... 

A CONVENIENT PREPARATION OF AN ORTHOGONALLY PROTECTED C ,C -DISUBSTITUTED AMINO ACID ANALOG OF LYSINE l-tert-BUTYLOXYCARBONYL-4-((9-FLUORENYLMETHYLOXYCARBONYL)AMINO)-PIPERIDINE-4-... 

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

A nitrogen-protective benzyl group was hydrogenolytically removed and replaced by a tert-butyloxycarbonyl moiety in a single operation. The protected compound and (Boc)20 in MeOH and 10% Pd/C were treated for 48 hours under 3 atm H2 (Scheme 4.79).325,326... 

Amino group protection may be achieved by converting the amine into its Al-tert-butyloxycarbonyl (tBOC or just BOC) derivative, by reaction with di-tert-butyl dicarbonate. This reagent should be considered as a variant of a carboxylic acid... 

The amino-oxy group can be incorporated into peptides or small molecules in the form of protected TV-tert-butyloxycarbonyl amino-oxy acetic acid (Boc-Aoa-OH, Nova Biochem). For peptides, the Aoa functional group can be coupled to the N-terminus. If the free N-terminus of the peptide is required for biological function, the Boc-Aoa-OH can be coupled to the side chain of some diamino acid (e g., diaminopropionic acid [Dpr], lysine [Lys], or ornithine [Om]) at the... 

The most common method for the preparation of 1,2,3-benzothiadiazoles (e.g., 440) is the diazotization of 2-aminobenzenethiol or its derivatives . This method has been extended to include heterocyclic derivatives thus the tert-butyloxycarbonyl (Boc)-protected derivative of 2-aminothiophene 441 can be converted into the thienothiadiazole 442 on treatment with sodium nitrite in HC1 in high yield (Scheme 229) <1999JHC761>. 

The temporary amino protecting group most commonly employed in the liquid phase method is A-tert-butyloxycarbonyl (Boc). This group can be removed from... 

It was shown that amide formation can be suppressed by the appropriate choice of reaction conditions, such as homogeneous solutions, e.g. in DMF, DMSO, HMPA, high acidity and low temperatures (-30 to -5°C). If the peptide hydrazide contains acid-labile protecting groups, e.g. trityl, 2-(4-biphenyl)propyloxycarbonyl, tert-butyloxycarbonyl, tert-butyl esters and ethers, the temperature has to be kept below -20 °C. Generally, tert-butyl or butyl nitrite is used as the organic nitrite, and for sterically hindered peptides amyl nitrite is employed. The time required for full conversion of the hydrazide into the azide may vary between 5 to 30 min and can be monitored by spray reagents (see experimental procedure below). 

A perfluoro-tagged tert-butyloxycarbonyl group ( Boc) has been used for the protection of primary amino functions in the synthesis of a small amide library [29]. The Boc-protected amino acids were coupled wifh primary or secondary amines. The products were purified by preparative fluorous HPLC. After deprotection by add treatment, the products were isolated by conventional extractive work-up. 

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