A novel approach to isoindolo[2,1-a]indol-6-ones

Abstract

A convenient route to isoindolo[2,1-a]indol-6-ones has been developed starting from the appropriate 2-(N-phthaloyl)benzoic acids. Formation of the acid chlorides with thionyl chloride followed by heating with triethyl phosphite in a suitable solvent resulted in a multistep reaction giving tetracyclic β-ketophosphonates that on reduction with sodium borohydride gave the required indolones in good overall yields. Analogous β-ketophosphonates were also prepared starting with N,N-(1,8-naphthaloyl)-2-aminobenzoic acid and 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzoic acids although of these only the naphthaloyl product could be reduced with sodium borohydride without cleaving the amide bond in the ring system.

One-pot three-component synthesis of peptidomimics for investigation of antibacterial and antineoplastic properties

“…Over the last three decades, organophosphorus compounds have been notably recognized for their pharmacological anticancer (Pratt, 1989;Wardle et al, 2005) and antibiotic activity (Duncanson et al, 2012), especially when they are associated with various heterocycles (Franco et al, 1995). One of the most important of these bioactive heterocycles is the pyrazole nucleus (Lee et al, 2003;Elguero, 1996).…”

Synthesis of 6H‐Isoindolo[2,1‐a]indol‐6‐ones Through Wittig Reaction and Tandem Reductive Cyclization–Lactamization

“…Monneret et al [2,5] synthesized isoindoloindolones using intramolecular Wittig cyclization as a key step. Griffiths et al [10] developed a route to isoindoloindolones starting from 2-(Nphthaloyl)benzoic acids via β-ketophosphonates. Boussard [ [7] developed a cascade approach involving sigmatropic shift-elimination-cyclization reaction of methyl 2-(indol-1-yl)benzoate by flash vacuum pyrolysis (FVP).…”

“…Bao [9] and co-workers prepared a series of isoindoloindolones from ortho-gem-dibromovinyl aniline through one-pot sequential Cu catalyzed C-N coupling and Pd catalyzed C-H activation reaction. Griffiths et al [10] developed a route to isoindoloindolones starting from 2-(Nphthaloyl)benzoic acids via β-ketophosphonates. However, many of these syntheses are either lengthy or involve complex precursors, thus, a simple, efficient, and versatile syn-thetic route would increase the scope for preparing structurally similar derivatives for biological and other studies.…”

Isoindoloindolones - biological activities and syntheses

“…Griffiths and his group 26 developed a novel route to isoindoloindolones using o-(Nphthaloyl)benzoic acids 34 (Scheme 11, Table 7). The process involves formation of acid chlorides followed by reaction with triethyl phosphite to give tetracyclic-β-keto phosphonates 35 via a carbon-carbon bond forming reaction involving phosphonate anion.…”