SYNTHESIS, CYCLIZATION, AND EVALUATION OF THE ANTICANCER ACTMTY AGAINST HeLa S-3 CELLS OF ETHYL 2-ACETYLAMINQ-3-ETHYNYLAZULENE-1-CARBOXYLATES1'

摘要

Reaction of ethyl 2-aminoazulene-1-carboxylate with NIS in CHCl3 gave 2,2'-diamino-3,3'-diethoxycarbonyl-1,1'-biazulene (3) and a terazulene derivative. The coupling of azulenes was catalyzed by acid. Operation of the reaction in the presence of Et3N in CH2Cl2 for 7 min at -7 °C retarded the coupling of the azulene nuclei to give ethyl 2-amino-3-iodoazulene-1-carboxylate (1a) in 95% yield. Sonogashira cross-coupling of ethyl 2-acetylamino-3-iodoazulene-1-carboxylate (lb) gave ethyl 2-acetylamino-3-ethynylazulene-1-carboxylates (5a and 5b) in good yields. Cyclization of ethyl 2-acetylamino-3-phenylethynylazulene-1-carboxylate with Pd-catalyst gave azuleno[2,1-b]pyrrole derivatives. Compounds (3 and 5b) showed potent cytotoxic activity against HeLa S-3 cells (IC50 [μM] : 3: 2.9 ± 0.2,5b: 13.4 ± 1.1).