Synthesis and in vitro antitumor activity of multi-methoxyl carbazole analogues

AimTo design and synthesize new methoxyl carbazole analogues as antitumor compounds. MethodsMethoxyl-nitrobiphenyls (3_a-3_c) were prepared through the Ullmann reaction of 4,5-dimethoxyl-2-bromonitrobenzene and methoxyl-iodobenzene compounds with the catalysis of copper powder, and then reduced by P(EtO)₃ to obtain methoxyl carbazoles 4_a-4_c. The modification at 9-position of the methoxyl carbazoles (4_a-4_c) gives 16 carbazole derivatives (5_a-5_p). These compounds were confirmed by ¹HNMR, MS, IR and elemental analysis. Resultin vitro antitumor activities evaluation in vitro demonstrated that IC₅₀ value of the target compounds 4_c, 5_a, 5_b, 5_g, 5_h, 5_i, 5_I, 5_n and 5_p against HT-29 cells were 12.1, 10.6， 8.1， 3.1， 4.4， 10.1 and 9.2 μmol·L^-1 respectively, and IC₅₀ value of the target compound 4_a against KB was 17.7 μmol·L^-1. ConclusionSome of the target compounds have better inhibitory effects against H-29 and KB cells.