F-Boc protecting group

Acts as a catalyst for cleaving the f-Boc protecting group from amino acids in peptide synthesis (Section 26.7). 

Synthesis of the four-helix bundles was accomplished by a two-step procedure (outlined as a flow chart in Figure 2). Proteins were synthesized by solid phase methods in accordance with general principles (62-64) using a peptide synthesizer (model 431, Applied Biosystems (ABI), Foster City, CA). L-con-figuration amino acid derivatives were used (The Peptide Institute, Osaka, Japan). The acid-labile fert-butyloxycarbonyl- (f- Boc)-protecting groups were... 

After the C-terminal amino acid is attached to the resin, the f-BOC protecting group is removed (Section 23.9). The next amino acid, with its amino group protected with f-BOC and its carboxyl group activated with DCC, is added to the column. 

After the C-terminal amino acid is attached to the resin, the f-BOC protecting group is removed (Section 22.10). The next amino acid, with its amino group protected with t-BOC and its carboxyl group activated with DCC, is added to the colunm, and then its protecting group is removed. Then the next N-terminal-protected and C-activated amino acid is added to the column. Thus, the protein is synthesized from the C-terminal end to the N-terminal end. (Proteins are synthesized in nature from the N-terminal end to the C-terminal end Section 26.9.) Because the process uses a solid support and is automated, Merrifield s method of protein synthesis is called automated solid-phase peptide synthesis. 

Then, we synthesized AB6 dendron 31 with six molecules of aminomethyl-pyrene as reporter units and the f-butyloxycarbonyl (Boc) protecting group as a trigger (Fig. 5.23). The dendron was designed to release its six tail units upon removal of the protecting group. 

Hydrolysis of the hydrazine BOC-protecting group of 90 followed by treatment with sodium hydride gave pyrazolo[4,3-f][l,2,4]triazine-3-one 44 by nucleophilic cyclization onto the 5-ethoxycarbonyl group (Scheme 64) <2006JA5646>. 

C. Agami, F. Couty, The Reactivity of the N-Boc Protecting Group An Underrated Feature, Tetrahedron 2002, 58, 2701-2724. 

Gibson, F. S. Bergmeier, S. C. Rapoport, H., Selective Removal of an N-BOC Protecting Group in the Presence of a tert-Butyl Ester and Other Acid-Sensitive Groups. J. Org. Chem. 1994, 59,... 

A mixture of an F-Boc-protected diamine with a slight excess of benzoic acid, aldehyde, and isonitrile in MeOH was subjected to MW irradiation for 10-20 min at 100 °C to give the linear Ugi product 39. Subsequent deprotection of the amine group (de-Boc) induced cyclization and the final product 38 was formed after 10-20 min, again under MW irradiation, now in TFA-THF (1 1). The reaction mixture was purified by fiuorous solid-phase extraction (F-SPE) and afforded 38 in up to 67% yield. 

Later, it was found that the imidazole-iV-carboxylate esters (35 and 36) formed by the reaction of 1 and either secondary or tertiary alcohols react selectively with primary hydroxyls in polyols containing mixtures of primary, secondary, and tertiary hydroxyls, without the need for protecting group chemistry (eq 29). With this method, selective f-Boc protection of primary hydroxyl groups could be easily achieved through a single step. 

J f-(6-Diphenylphosphinopyridine-2-carbonyl)-guanidine, another type of such self-assembling ligands, has been prepared in a 10 g scale by the condensation of diphenylphosphinopyridine-2-carboxyhc acid with Boc-protected guanidine in the presence of the peptide-couphng reaction BOP (Scheme 2.3) [9]. After removal of the Boc-protective group, the multifunctionalized phosphine was ready for screening in several rhodium-catalyzed tandem reactions [10]. 

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