N-propargyl-2-alkynylbenzothiazolium aza-enediynes:: Role of the 2-alkynylbenzothiazolium functionality in DNA cleavage

The 2-alkynylbenzothiazolium salts 3a-d incorporating an N-propargyl moiety have been prepared as aza-enediyne analogues. While these aza-enediynes are shown to be modest DNA cleavage agents, DNA cleavage was also observed with the N-methyl-2-alkynylbenzothiazolium salt 4, which lacks the aza-enediyne moiety. The structural requirements for DNA cleavage, and the correlation of DNA cleavage efficiency with the propensity of these compounds to undergo nucleophilic addition by methanol support a proposed DNA cleavage mechanism involving DNA alkylation. by appropriate 2-alkynyl-substituted benzothiazolium salts. (C) 2001 Elsevier Science Ltd. All rights reserved.