Protecting Group Combinations

P Sieber, B Iselin. Peptide synthesis using the 2-(p-diphenyl)-isopropoxycarbonyl (Dpoc) amino protecting group. Helv Chim Acta 51, 622, 1968. 

R Schwyzer, B Rittel. Synthesis of intermediates for a corticotropic nonadecapeptide. I. A, -ferf-Butoxycarbonyl-L-lysine, A a(M-/c rt-biitoxycarbonyl-i,-lysyl)-/Vr-/ rt-butoxycarbonyl-L-lysine, M-tert-butoxycarbonyl-L-lysyl-i.-prolyl-i.-valylglycine and derivatives. Helv Chim Acta 44, 159, 1961. 

R Schwyzer, P Sieber. The total synthesis of adrenocorticotrophic hormone. Nature 199, 172, 1963. 

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

C-D Chang, J Meienhofer. Solid-phase synthesis using mild base cleavage of Na-fluorenylmethoxycarbonylamino acids, exemplified by a synthesis of dihydrosoma-tostatin. Int J Pept Prot Res 11, 246, 1978. 

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Different Amino and Carboxyl Protecting-Group Combinations of L-Serine/L-Threonine Used for Glycopeptide Chain-Lengthening... 

PROTECTING GROUP COMBINATIONS FOR SOLID-PHASE SYNTHESIS... 

FIGURE 5.13 Protecting group combinations employed in solid-phase synthesis. The protector written in italics is removed after each residue is incorporated into the chain. (A) Boc/Bzl3 is not an orthogonal system — all substituents are removed by acidolysis. (B) Fmoc/tBu27 [Atherton et al., 1978] is an orthogonal system - Fmoc is removed by P-elimi-nation, other substituents by acidolysis. More suitable variants of the side-chain protectors are also used. 

M. Ciommer and H. Kunz, Synthesis of glycopeptides with partial structure of human glycophorin using the fluorenylmethoxycaibonyl/allyl ester protecting group combination, Synleti p. 593 (1991). 

H. Kunz and 1. Miirz, Synthesis of glycopeptides with Lewis antigen side chain and HIV peptide T sequence using the trichloroethoxycaibonal/allyl ester protecting group combination, Synlett p. 591 (1992). 

Sheppard RC, Williams BJ, A new protecting group combination for solid phase synthesis of protected peptides, J. Chem. Soc. Chem. Commun., 587-589, 1982. 

Conventional method stepwise synthesis or fragment condensation using an optimized choice of protecting group combination and the most favorable coupling methods 1 8 ... 

The UDP-activated sugars and GDP-Man are a-phosphates and their chemical S5mthesis poses greater problems. Although various protecting group combinations and phosphorylation protocols were investigated, none led to the exclusive formation of the desired a-phosphates (see Schemes 3 and 6). The purification of those compoimds is further hampered by their notorious instability. 

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