Tiechao Li

Aryl[a]pyrrolo[3,4-c]carbazoles as selective cyclin D1-CDK4 inhibitors

The synthesis of new analogues of Arcyriaflavin A in which one indole ring is replaced by an aryl or heteroaryl ring is described. These new series of aryl[a]pyrrolo[3,4-c]carbazoles were evaluated as inhibitors of Cyclin D1-CDK4. A potent and selective D1-CDK4 inhibitor, 7a (D1-CDK4 IC(50)=45 nM), has been identified. The potency, selectivity profile against other kinases, and structure-activity relationship (SAR) trends of this class of compounds are discussed.

Studies on cyclin-dependent kinase inhibitors: indolo-[2,3-a]pyrrolo[3,4-c]carbazoles versus bis-indolylmaleimides

A series of indolo[2,3-a]pyrrolo[3,4-c]carbazoles and their bis-indolylmaleimides precursors have been prepared in order to compare their activity as D1-CDK4 inhibitors. Both enzymatic and antiproliferative assays have shown that the structurally more constrained indolo[2,3-a]pyrrolo[3,4-c]carbazoles are consistently more active (8-42-fold) in head-to-head comparison with their bis-indolylmaleimides counterparts. Cell-cycle analysis using flow cytometry have also shown that the indolocarbazoles are selective G1 blockers while the bis-indolylmaleimides arrest cells in the G2/M phase.

Novel 1,3-disubstituted-5,10-dihydro-5,10-dioxo-1H-mbenzo[g]isochromene-3-carboxamides as potent antitumor agents

Novel antitumor 5,10-dihydro-5,10-dioxo-1H- benzo[g]isochromene-3-carboxamides were discovered.

Dehydrogenation by air: Preparation of 1,3-disubstituted-5,1-dioxo-5,10-dihydro-1H-benzo[g] isochromene scaffold

Naphthaquinopyrans 5a-d, 10 and 12 have been converted to benzoisochromene IIb via base-promoted air oxidation. A mechanism is proposed to account for the observed results. Use of peroxide scavenger was found necessary for consistent yields. IIb proved to be a versatile scaffold for diversity expansion.