Synthetic Studies on Indolocarbazoles: A Facile Synthesis of Staurosporinone Analogues

Abstract

Synthesis of indolocarbazoles was achieved through thermal electrocyclization followed by triethyl phosphite‐mediated nitrene insertion reactions. Total synthesis of staurosporinone analogues was achieved from commercially available 2‐methylindole. The CDK5/p25 kinase inhibition potential of some representative staurosporinone analogues was explored by using the TRFRET kinase assay.

The synthesis of biologically active indolocarbazole natural products

“…The same group subsequently reported extending the approach to synthesise a variety of aglycone analogues. 84 An approach centred on strategic C-H functionalisations was published in 2016 by Gaunt and co-workers, which exploited the amine moiety in the central ring to direct four out of the seven key transformations (Scheme 16). 85 Ortho-arylation of aniline 108 was followed by hydrogenolysis and carbamoylation to switch the directing nature of the group and give anilide 110.…”

Copper‐Mediated Decarboxylative Coupling of Benzamides with ortho‐Nitrobenzoic Acids by Directed C−H Cleavage

“…Subsequent dehydrative chlorination of 12 aa furnished the 6-chlorophenanthrizine 13 aa in ag ood overall yield, and it can serve as ac oupling partner in various metal-catalyzed cross-coupling reactions.T he nitro group can also work as an itrene equivalent, and 3aa was transformed into the corresponding carbazole 14 aa in 65 %yield upon treatment with P(OEt) 3 . [23] Scheme 4. Copper-mediateddecarboxylativeC ÀHa rylation and cyclization sequence.…”

Copper‐Mediated Decarboxylative Coupling of Benzamides with ortho‐Nitrobenzoic Acids by Directed C−H Cleavage

“…Thec orresponding product 3aa is finally formed by reductive elimination following decarboxylation. [23] Scheme 4. The8 -aminoquinolinyl directing group of 3aa and 3da was easily removed in heated methanol with BF 3 ·OEt 2 to produce the corresponding methyl esters 10 aa and 10 da in 75 and 58 %, respectively.I na ddition, the nitro group can be aversatile synthetic handle,asthereaction of the nitrobiphenyls 10 with PhMgBr (3.0 equiv) formed 4,6diarylphenanthrizines 11 through nucleophilic acyl substitution at the ester,t ransformation from nitrobenzenes to 2amino-2'-hydroxy-1,1'-biaryls by [3,3] sigmatropic rearrangement, [22] and intramolecular condensation.…”