N-deacetyl-N-aminoacylthiocolchicine derivatives:: Synthesis and biological evaluation on MDR-positive and MDR-negative human cancer cell lines

A new series of N-deacetyl-N-(N-trifluoroacetylaminoacyl)thiocolchicine derivatives 9-15 have been synthesized starting from the corresponding N-deacetylthiocolchicine (3) and the N-trifluoroacetylamino acids 5-8 which were used as a racemic mixture. The trifluoroacetyl protecting group has been removed easily, giving the corresponding N-deacetyl-N-aminoacylthiocolchicines 16-22. Optical pure compounds 9-22 were isolated from the diastereoisomeric mixture or were prepared starting from compound 3 and an optical pure amino acid derivative; the configuration of each compound was assigned unequivocally. The diastereoisomeric couples of amino acids synthesized were tested, and their antiproliferative activity on MDR-positive and MDR-negative human cancer cell lines was evaluated.