Synthesis of pyrrolo[3,4-c]quinoline-1,3-diones: a sequential oxidative annulation followed by dehydrogenation andN-demethylation strategy

Abstract

A synthetic strategy for pyrrolo[3,4-c]quinoline-1,3-diones via oxidative annulation followed by DDQ mediated dehydrogenation and N-demethylation.

Photochemical Reaction of N,N‐Dimethylanilines with N‐Substituted Maleimides Utilizing Benzaldehyde as the Photoinitiator

“…The past decade, various methods for the synthesis of tetrahydro‐pyrrolo[3,4‐c]quinolinones, which via aromatization can lead to the desired pyrrolo[3,4‐c]quinolinones, [7d,e] have been developed, primarily focusing on the oxidative annulation by utilizing a catalyst and either air or oxygen or a chemical reagent as the oxidant. Various examples exist in literature employing mainly metal catalysts [7] .…”

“…For example, Kang and coworkers showed that the reaction can be performed with the use of an iron (III) complex and as the external oxidant, which is essential for the completion of the transformation, they used either TBHP or air (Scheme 1A) [7e] . Similarly, Gogoi and coworkers used CeO 2 as the catalyst and air as the oxidant, in order to perform this oxidative annulation (Scheme 1B) [7d] . Photocatalysis has also proposed a number of synthetic approaches for the synthesis of these scaffolds, [8,9] although in most cases metal complexes have been employed as the photocatalyst.…”

Efficiently Constructing Tetrahydroquinolines through Cascade Radical Additions and Cyclizations under the Catalysis of CuI

“…[3] However, in the transformations, only 44-68 % yields for the tetrahydroquinolines could be obtained when N,N-dimethylanilines and 2benzylidenemalononitrile were used as the substrates. Subsequently, Sharma et al developed a CeO 2 catalyst for the oxidative annulation reaction between N,N-dimethylanilines and maleimides to give cyclized product tetrahydroquinolines, [4] but the organic peroxides TBHP (tertbutylhydroperoxide) was required in the transformation. It is generally acknowledged that nucleophilic α-amino alkyl radical generates as the active intermediate, and attacks unsaturated double bonds in the reaction.…”

“…[3,5] Since then, the radical addition of tertiary amines to various deficient unsaturated systems through photoinduced electron transfer process has been described, and several photocatalytic systems have been reported. However, most of these synthetic strategies still suffer from some impediments, [4][5][6] such as high energy UV irradiation, expensive and rare transition metals (Pd, Ru, Rh, and Ir), complicated catalyst structure, or requirement of base or acid additions. Hwang and coworkers have developed an efficient catalytic system for the formation of α-aminoalkyl radicals based on Fe complex, which behaves similarly to bioinspired heme iron catalysts.…”

An Efficient Five‐Component Reaction for the Synthesis of 4,4′‐((2‐Oxoindoline‐3,3‐diyl)bis(methylene))bis(2‐aryl‐1H‐pyrrolo[3,4‐c]quinoline‐1,3(2H)‐dione) Derivatives

“…As a versatile synthetic substrate, isatins can be used to synthesize a variety of organic compounds , which is also an efficient reagent for the preparation of pyrrolo[3,4‐ c ]quinoline derivatives [5a,5b,6b,11,12]. Other methods for the synthesis of quinoline have also been reported . In addition, 3‐oxo‐ N ‐arylbutanamide was also the important reagent in organic synthesis, and lots of compounds were prepared from this substrate .…”