Synthesis of All-l Cyclic Tetrapeptides Using Pseudoprolines as Removable Turn Inducers

Cyclic tetrapeptides have generated great interest because of their broad-ranging biological properties. In order to synthesize these highly strained 12-membered cyclic compounds, a cyclization strategy using pseudoprolines as removable turn inducers has been developed. The pseudoproline derivatives induce a cisoid amide bond in the linear peptide backbone which facilitates cyclization. After cyclization, the turn inducers can be readily removed to afford cyclic tetrapeptides containing serine or threonine residues.

环状四肽因其广泛的生物学特性而备受关注。为了合成这些高度张力的12元环状化合物，一种采用伪脯氨酸作为可移除的转折诱导剂的环化策略已被开发。伪脯氨酸衍生物在直链肽骨架中诱导形成顺式酰胺键，从而促进环化。环化完成后，转折诱导剂可轻易去除，从而得到含有丝氨酸或苏氨酸残基的环状四肽。