Synthesis, structure and cytotoxicity of trimethylsilyl oligothienylcarbaldehydes and their derivatives

Trimethylsilyl end-capped bi- and terthiophene carbaldehydes were prepared by reaction of bi- and terthienyl lithium with DMF. Condensation of 5-trime thylsilyl-2,2'-bithiophene-5'-carbaldehyde with dinitrile of malonic acid g ave silylbithienyl methylidenedinitrile in good yield, while reaction with hydroxylamine was accompanied by desilylation. The reaction of hydroxylamin e with silylbithienyldinitrile leads to the formation of 2-[5-(5'-trimethyl silyl-2,2'-bithienyl)methylidene]malonic acid bisamidoxime. The cytotoxic e ffect of bi- and terthiophene derivatives was investigated in vitro on two monolayer tumor cell lines: MG-22A (mouse hepatoma) and HT-1080 (human fibr osarcoma). The molecular structure of 5-trimethylsilyl-2,2'-bithiophene-5'- carbaldehyde was studied by X-ray diffraction. (C) 2001 Elsevier Science B. V. All rights reserved.