Iminoiodane mediated aziridination of α-allylglycine: access to a novel rigid arginine derivative and to the natural amino acid enduracididine

The synthesis of fully protected aminodihydrohistidines in optically pure form is described starting from allylglycine derivatives. These compounds represent novel conformationally constrained analogues of arginine, one of them being, in addition, a protected form of the marine natural product, enduracididine. The key step of the strategy is a one-pot copper-catalyzed aziridination of t-butyl (S)-N-(9-phenyl-9H-fluoren-9-yl)allylglycinate ((S)-16) with 2-trimethylsilylethanesulfonamide in the presence of iodosylbenzene.     

Solid phase synthesis of mono- or disubstituted arginine containing peptides from an isothiocitrulline precursor

A method for the solid phase synthesis of substituted arginine containing peptides starting from an isothiocitrulline precursor is described. In this procedure, a peptide containing one or more protected ornithine residue(s) was assembled on a solid support. Following selective deprotection, ornithine residue(s) was (were) converted into S-methyl-isothiocitrulline in three steps. Subsequent reaction with primary or secondary amines afforded mono and disubstituted arginine-containing derivatives, respectively. Using lysine instead of ornithine afforded substituted homoarginine-containing derivatives.     

Studies on Some Gadolinium（Ⅲ） Complexes as New Water－Soluble Paramagnetic Relaxation Reagents（RR） for ￣（13）C NMR Spectrometry

ＳｔｕｄｉｅｓｏｎＳｏｍｅＧａｄｏｌｉｎｉｕｍ（Ⅲ）ＣｏｍｐｌｅｘｅｓａｓＮｅｗＷａｔｅｒ－ＳｏｌｕｂｌｅＰａｒａｍａｇｎｅｔｉｃＲｅｌａｘａｔｉｏｎＲｅａｇｅｎｔｓ（ＲＲ）ｆｏｒ￣（１３）ＣＮＭＲＳｐｅｃｔｒｏｍｅｔｒｙＷＡＮＧＹｉｎｇ－ｚｉ,ＺＨ...