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2016 Volume 36 Issue 1
2016, 36(1): 121-129
doi: 10.6023/cjoc201507012
Abstract:
The isatin derivatives 4a～4f were prepared and underwent oxidative hydrolysis to give the anthranilic acid 5a～5d. A and/or D-ring substituted tryptanthrins were designed and synthesized from 4a～4f to 5a～5d. Then C-ring Schiff bases of tryptanthrin were synthesized by condensation of 6-carbonyl with hydrazine and hydroxylamine hydrochloride. Finally, the B-ring was replaced with piperazine to give 11H-indeno[1, 2-b]quinoxalin-11-one. 20 compounds were synthesized and their structures were confirmed by 1H NMR, IR and elemental analysis. To best of our knowledge, 13 of them were unknown in the literature. The antitumor activities of synthesized compounds were evaluated against A549 cell line in vitro. The preliminary results indicated that 1b, 1c, 1i, 1j, 1p and 1q showed good antitumor activity with the IC50 of 3.58, 0.99, 1.03, 2.10, 0.51 and 0.43 μmol·L－1, respectively. Structure-activity relationship showed that halogen substitution located in the D-ring enhanced the anti-tumor activity, while the same substitution located in the A ring reduced the activity. The anti-tumor activity disappeared when B-ring was replaced by piperazine, while there was no significant difference for tryptanthrin and its C-ring Schiff base.
The isatin derivatives 4a～4f were prepared and underwent oxidative hydrolysis to give the anthranilic acid 5a～5d. A and/or D-ring substituted tryptanthrins were designed and synthesized from 4a～4f to 5a～5d. Then C-ring Schiff bases of tryptanthrin were synthesized by condensation of 6-carbonyl with hydrazine and hydroxylamine hydrochloride. Finally, the B-ring was replaced with piperazine to give 11H-indeno[1, 2-b]quinoxalin-11-one. 20 compounds were synthesized and their structures were confirmed by 1H NMR, IR and elemental analysis. To best of our knowledge, 13 of them were unknown in the literature. The antitumor activities of synthesized compounds were evaluated against A549 cell line in vitro. The preliminary results indicated that 1b, 1c, 1i, 1j, 1p and 1q showed good antitumor activity with the IC50 of 3.58, 0.99, 1.03, 2.10, 0.51 and 0.43 μmol·L－1, respectively. Structure-activity relationship showed that halogen substitution located in the D-ring enhanced the anti-tumor activity, while the same substitution located in the A ring reduced the activity. The anti-tumor activity disappeared when B-ring was replaced by piperazine, while there was no significant difference for tryptanthrin and its C-ring Schiff base.
