We describe an efficient one-pot regio- and stereoselective method for synthesizing diverse 1-hydroxy-12H-6,12-methanodibenzo[d,g][1,3]dioxocines and 3-hydroxy-12H-6,12-methanodibenzo[d,g][1,3]dioxocines using ethylenediammonium diacetate (EDDA) or p-toluenesulfonic acid (PTSA) catalyzed reactions between various resorcinols and a number of 2-hydroxychalcones. These reactions involve a catalyst-controlled cascade Michael-type reaction/double cyclization process. Importantly, these reactions provide a rapid synthetic route to the production of biologically interesting complex molecules that are generally prepared using multi-step reactions.

Ruthenium(II)‐phosphine complexes‐catalyzed [3+2] cycloadditions were conducted to synthesize a variety of dihydrofurans by reactions of cyclic or acyclic diazodicarbonyl compounds with olefins. This method represents a direct and efficient one‐pot synthesis for multi‐substituted dihydrofurans under mild reaction conditions with an excellent regioselectivity. Furthermore, to reduce reaction times and increase yields of dihydrofurans, microwave‐assisted tris(triphenylphosphine)ruthenium(II) chloride/ 1‐butyl‐3‐methylimidazolium tetrafluoroborate {Ru(PPh3)3Cl2/[Bmim]BF4}‐catalyzed reactions were also developed. The synthesized dihydrofurans can be readily converted into biologically interesting tetrahydroindoles.magnified image

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We describe an efficient one-step synthesis of pyrrolo[3,4-c]quinolinedione derivatives using ethylenediamine diacetate (EDDA)-catalyzed cascade reactions of isatins and β-ketoamides. It is the first direct conversion of isatins to pyrrolo[3,4-c]quinolinedione derivatives via C-N bond cleavage and isatin ring expansion. Furthermore, this reaction provides a one-step synthetic route for the production of biologically interesting complex molecules that are generally prepared using multi-step reactions.

With the aim of developing a general and practical method for library production, a novel and efficient two-phase microwave-assisted cascade reaction between isatins and β-ketoamides in [Bmim]BF4/toluene was developed for the synthesis of pyrrolo[3,4-c]quinoline-1,3-diones. The features of this methodology are, the use of microwave-assisted rapid synthesis, mild reaction conditions, high yields, operational simplicity, facile product separation, and recyclability. Furthermore, the antibacterial activities of the pyrrolo[3,4-c]quinoline-1,3-dione derivatives produced were evaluated against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus). These derivatives showed antibacterial activities against Gram-positive strains that were at least equivalent to that against Gram-negative strains. Compound 7{3,5} displayed the most potent antibacterial activity against P. aeruginosa (MIC = 0.5 μg/mL) and greater activity than standard ampicillin (MIC = 1 μg/mL). Compound 7{4,7} exhibited the best inhibitory activity against E. coli and E. aerogenes (MIC = 1 and 0.5 μg/mL), compared with the standard ampicillin (both MICs = 1 μg/mL). The synthesized pyrrolo[3,4-c]quinoline-1,3-diones are expected to be widely used as lead compounds for the development of new antibacterial agents.