| abstract |
Amino-acids contg. protecting gps. such as t-butoxycarbonyl, t-amyloxycarbonyl, benzhydryloxycarbonyl, benzyloxycarbonyl, p-methoxybenzyloxycarbonyl or 2-phenyl-isopropoxycarbonyl, are useful in peptide synthesis. They are prepd. readily in very high yields by reacting a mixed phenyl carbonate contg. the desired protecting gp. with the aminoacid to be protected in a dipolar solvent (e.g., DMF or DMSO) in the presence of a very strong org. base (e.g., 1,1,3,3-tetramethylguanidine) and isolating the protected amino-acid from the reaction mixt. |