An improved stereocontrolled synthesis of pyochelin, siderophore of Pseudomonas aeruginosa and Burkholderia cepacia

A considerably improved stereocontrolled synthesis of pyochelin, a hydroxyphenylthiazolinylthiazolidine type of siderophore common to most strains of Pseudomonas aeruginosa and Burkholderia cepacia is described. 2'-(2-Hydroxyphenyl)-2'-thiazoline-4'-carbox-aldehyde, a key molecule involved in this synthesis has been prepared by reduction of 2'-(2-hydroxyphenyl)-2'-thiazoline-4'-(N-methoxy,N-methyl) carboxamide with lithium aluminium hydride. The aldehyde was further coupled with (R)-N-methylcysteine to yield pyochelin. Under the conditions reported, epimerization at the C-4' center was considerably diminished. (C) 1999 Elsevier Science Ltd. All rights reserved.