Acm, acetamidomethyl

Triphenylmethylcysteine is readily oxidized by iodine (MeOH, 25°) to cystine." The 5-triphenylmethylcysteine group can be selectively cleaved in the presence Of a —Cys(Acm)— group (Acm = acetamidomethyl). 5-Ben-zyl and 5-/-butyl thioethers are stable to the action of iodine. 

FIGURE 6.23 The synthesis of insulin, starting with a cystine-containing peptide. [Kamber et al., 1977]. Moc = methoxycarbonyl, Bpoc = biphenylisopropoxycarbonyl, Trt = trityl, Acm = acetamidomethyl. (a) HOBt-assisted carbodiimide-mediated coupling (b) removal of Trt by HC1 in CF3CH2OH-CH2Cl2 (9 1) at pH 3.5 (c) removal of Bpoc by CF3CH2OH-CH2 Cl2 (9 1) at 60°C (d) removal of Acm and oxidation by iodine. 

Scheme 8. Solid-phase synthesis of a 71-mer vMIP-1 protein segment 34 (Acm, acetamidomethyl BnSH, benzyl mercaptan Boc-SPPS, solid-phase peptide synthesis by the Boc strategy).

SCHEME 11.1 Native chemical ligation and a concept using amino acid having thiol at the (i position. Acm, acetamidomethyl PG, protecting group VA-044,1,2 - azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride. 

Abbreviations Standard abbreviations as recommended by IUPAC-1UB Commission are used in this review (1). Other abbreviations include Acm, acetamidomethyl Bn, benzyl Boc t-butyloxycarbonyl Bom, benzyloxymethyl BHA, benzhydrylamine Cbz, benzyloxycarbonyl cHx, cyclohexyl DCC, N,N-dicyclohexylcarbodiimide DCM, dichloromethane Die, N,N-diisopropylcarbodiimide DMF, N,N-dimethylformamide DMSO, dimethyl sulphoxide For, formyl Fmoc, 9-fluorenylmethyloxycarbonyl HMP, 4-hydroxymethylphenoxyacetyl HOAt,... 

Acm, acetamidomethyl Boc, r rf-butyloxycarbonyl EDTA, ethylenediami-notetraacetic acid Fmoc, 9-fluorenylmethyloxycarbonyl GSH, glutathione (H-y-Glu-Cys-Gly-OH) GSSG, glutathione disulfide Meb, 4-methylbenzyl Mmt, 4-methoxytrityl Mob, 4-methoxybenzyl Npys, 3-nitro-2-pyridinesul-fenyl Tf, trifluoromethanesulfonyl TEA, trifluoroacetic acid Tris, tris(hydroxymethyl)aminomethane Trt, trityl (triphenylmethyl). 

Ac = acetyl Acm - acetamidomethyl AOC = t-amyloxycarbonyl IBM = isobutyloxymethyl BhOC = benzhydryloxycarbonyl BMD = bismethylenedioxy BOC = t-butyloxycarbonyl Btm = benzylthiomethyl... 

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