N-ferf-Butoxycarbonylation

Khalil, E. M. Subasinghe, N. L. Johnson, R. L., An Efficient and High Yield Method for the N-ferf-Butoxycarbonyl Protection of Sterically Hindered Amino Acids. Tetrahedron Lett. 1996, 37, 3441. 

These include l,3-bis[diphenylphosphino]propane (DPPP), 2,2 -bis[diphenylphosphino]-l,T-binaphthyl (BINAP), [2,2,-dimethyl-l,3-dioxolane-4,5-diylbismethylene]bisdiphenyl-phosphine (DIOP), N-(ferf-butoxycarbonyl)-4-(diphenylphosphino)-2-[(diphenylphos-phino)methyl]pyrrolidme (BPPM)... 

In a similar way, Hawker and Hedrick [220] synthesized a-amino,cw-aminoxyl PS. Before performing the NMP of styrene, they synthesized a new protected amino diazoic initiator by reaction of N-(ferf-butoxycarbonyl)-4-aminophenol with a bisacid chloride diazo initiator. The resulting initiator was heated in the presence of styrene and TEMPO at 130 °C (Scheme 37). 

Methyl ester of N-ferf-butoxycarbonyl-(Z)-(3-bromodehydroaminobutyric acid, 0.14 g, 0.5 mmol... 

The synthesis of glycopeptides of L-asparagine by the solid-phase procedure required a derivative protected, for example, by the acid-labile N-(ferf-butoxycarbonyl) group. Thus, 1-benzyl N-(terf-butoxycarbonyl)-L-aspartate (88) was condensed with 2,3,4,6-tetra-0-acetyl-)3-D-gluco-pyranosylamine (2), or the 2-acetamido-2-deoxy analog 8, by the active ester method in the presence of DCC and 1-hydroxybenzotriazole, to give 89 and 90, respectively ... 

It has been suggested that protein modifications by malondialdehyde, a major product of hpid peroxidation, contribute to the fluorescence formation of lipofuscin (Kikugawa and Beppu 1987, Tsuchida et al. 1987, Yin 1996). However, Itakura and UCHiDA (2001) isolated an aminoenimine, N,N -bis[5-(terf-butoxy-carboxamido)-5-carboxypent]-l-amino-3-iminopropene, formed from the reaction of malondialdehyde with a lysine derivative, N -ferf-butoxycarbonyl-L-lysine, at neutral pH, and confirmed that the purified Ar,hr-bis[5-(tert-butoxy-carboxyamido) - 5- carboxypent] -1 -amino- 3-imino-propene, exhibited no fluorescence. 

Using curved arrows to symbolize the flow of electrons, write a stepwise mechanism for the formation of N-ferf-butoxycarbonyl-L-alanine from L-alanine and di-fcrf-butyl dicarbonate according to Equation 24.4. 

Discuss the differences observed in the IR and NMR spectra of N-ferf-butoxy-carbonyl-L-alanine, methyl L-phenylalaninate hydrochloride, and methyl N-ferf-butoxycarbonyl-L-alanyl-L-phenylalaninate that are consistent with the formation of the latter in this procedure. 

N Itoh, D Hagiwara, T Kamiya. A new ferf-butoxycarbonylating reagent, 2-ferf-butyl oxycarbonyloxyimino-2-phenylacetonitrile. Tetrahedron Lett 4393, 1975. 

As mentioned in Section 10.6.2, synthesis of 1-hydroxyethylene peptides can be initiated by adding a ferf-butoxycarbonyl N-protected a-amino aldehyde to an optically active Grignard reagent (Scheme 7)J11-13 This reaction affords a diastereomeric mixture of the C4 epimers of the hydroxy ether in good yields. In most cases the mixture is enriched in the 45-epimer and the epimers are readily separable. The yields and the ratios of the resulting 45- and 4R-epimers obtained from several examples of this reaction are summarized in Table 1. When this reaction was attempted with the aldehyde prepared from Aa,Ae-bis-tert-butoxycarbonyl-protected Lys, the desired product was not obtained. The anion of the Lys Ne-tert-butoxy-carbonylamino group probably reacts with the aldehyde to form a cyclic aminol that does not... 

Reaction of 2-allylpiperidine 119 with N,N-di(ferf-butoxycarbonyl)thio-urea in the presence of HgCl2 yielded an epimeric mixtures of 3-(chloromercuriomethyl)perhydropyrido[l,2-c]pyrimidine 120 and 2-chloromercuriomethylperhydrofuro[3,2-fo] pyridine 121 (07C AR1813). 

To exploit the reactions of the C-lithio derivatives of N-unsubstituted pyrroles and indoles, N-protecting/masking groups such as ferf-butoxycarbonyl, terZ-biitylcarbamoyl, benzenesulfonyl, dimethylamino, and dimethylaminomethyl must be used. This is illustrated by a route to G-acylated pyrroles 441. Another very useful process involves N-lithiation, N-carbonation, and lithiation of the resulting indol-l-ylcarboxylate at C(2) reaction with an electrophile and loss of carbon dioxide during work-up give N-unsubstituted 2-substituted indoles, for example, 2-haloindoles in excellent yields. 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

In amino acid and peptide chemistry, the di-ferf-butyl dicarbonate (BocaO) is an extensively used reagent for the clean and rapid Boc-protection of amine functionalities.It is also an efficient ferf-butoxycarbonylating agent for alcohols, thiols, and carbon nucleophiles, and it has been used for the conversion of amines into isocyanates, carbamates, and urea derivatives.The reaction of amino acids with chloroformates to produce N-urethane-protected amino acids if not performed under optimal conditions is accompanied by the formation of N-protected oligomers this has been well documented in the case of and... 

The reaction of a tryptophan derivative, N- tert-butoxycarbonyl)-L-tryptophan, with hypoxanthine/ xanthine oxidase/Fe(III)-EDTA mainly resulted in the oxygenation of the pyrrole ring of the indole nucleus (Itakura etal. 1994). 2-[(ferf-Butoxy-carbonyl)-amino]-3-(3-indolyl)propionic acid and N- (fer f-butoxycarb onyl) -hT-formylkynurenine were identified as the major products. 

A further approach for the synthesis of nonsymmetrically protected lanthionines is the conversion of thiosulfinates of symmetrically protected cystine derivatives into nonsymmetrically protected cystines via a reaction with a cysteine derivative and subsequently the conversion of the resulting unsymmetrically protected cystine into the nonsymmetrically protected lanthionines with a tris(dialkylamino)phosphineJ26l The oxidation of the symmetrically protected cystine, e.g. A,AT-bis(benzyloxycarbonyl)-L-cystine diethyl ester, of one stereochemical configuration to the thiosulfinate with m-chloroperoxybenzoic acid is essentially quantitative. The nonsymmetrical cystine is then formed in a subsequent step by the addition of the /V-/er/-butoxycarbonyl-L-cysteine tert-butyl ester derivative to give N-Z-N -Boc-L-cystine ethyl ferf-butyl diester. The desired 2f ,6f -lanthionine is then formed in the presence of P(NEt2)3 in yields of >50%. 

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