Tubulin-binding dibenz[c,e]oxepines as colchinol analogues for targeting tumour vasculature

Abstract

Various methoxy- and hydroxy-substituted dibenz[c,e]oxepines were prepared via the copper(I)-induced coupling of ether-tethered arylstannanes or the dehydrative cyclisation of 1,1′-biphenyl-2,2′-dimethanols, assembled using the Ullmann cross-coupling of ortho-bromoaryl carbonyl compounds. The dibenzoxepines were screened for their ability to inhibit tubulin polymerisation and the in vitrogrowth of K562 human chronic myelogenous leukemia cells. The most active was 5,7-dihydro-3,9,10,11-tetramethoxydibenz[c,e]oxepin-4-ol, whose tubulin inhibitory and cytotoxicity (IC₅₀) values were 1 μM and 40 nM, respectively.