A Survey of Synthetic Routes and Antitumor Activities for Benzo[]quinoxaline-5,10-diones.

Anthracycline antibiotics play an important role in cancer chemotherapy. The need to improve their therapeutic index has stimulated an ongoing search for anthracycline analogs with enhanced properties. This review aims to summarize the common synthetic approaches to benzo[]quinoxaline-5,10-diones and their uses in heterocyclic chemistry.

Metal-Free Regiodivergent Addition of Carbon Nucleophiles to α,β-Unsaturated Electrophiles.

A mild and metal-free regiodivergent addition of carbon nucleophiles to α,β-unsaturated electrophiles was developed. Total 1,2-regioselectivity was observed in the addition of nitrobenzyl chloride derivative to α,β-unsaturated aldehydes in the presence of TDAE. Moreover, the reaction between -nitrobenzyl chloride and α,β-unsaturated iminium salts led to the formation of the 1,4-adduct with total regioselectivity.

Practical and Metal-Free Synthesis of Novel Enantiopure Amides Containing the Potentially Bioactive 5-Nitroimidazole Moiety.

We report here a practical and metal-free synthesis of novel enantiopure amides containing the drug-like 5-nitroimidazole scaffold. The first step was a metal-free diastereoselective addition of 4-(4-(chloromethyl)phenyl)-1,2-dimethyl-5-nitro-1-imidazole to enantiomerically pure --butanesulfinimine. Then, the --butanesulfinyl-protected amine was easily deprotected under acidic conditions.

Original Synthesis of Fluorenyl Alcohol Derivatives by Reductive Dehalogenation Initiated by TDAE.

We report here a novel and easy-to-handle reductive dehalogenation of 9-bromofluorene in the presence of arylaldehydes and dicarbonyl derivatives to give the corresponding fluorenyl alcohol derivatives and Darzens epoxides as by-products in tetrakis(dimethylamino)ethylene (TDAE) reaction conditions. The reaction is believed to proceed via two successive single electron transfers to generate the fluorenyl anion which was able to react with different electrophiles. A mechanistic study was conducted to understand the formation of the epoxide derivatives.