An Easy Access to Carbazolones and 2,3‐Disubstituted Indoles

Abstract

Synthesis of carbazol‐4‐ones, 3,4‐dihydrocyclopental‐indol‐1‐one, and indole derivatives by a Fe/AcOH‐mediated intramolecular reductive N‐heteroannulation of 3‐hydroxy‐2‐(2‐nitrophenyl)enones is demonstrated. The same protocol has been extended to access indolocarbazolone and indoloquinolone derivatives.

A practical one‐pot three‐component procedure for preparation of 3a,8a‐dihydroxyindeno[1,2‐d]imidazole derivatives in aqueous ethanol

“…A wide range of benzyl chlorides bearing electron donating and electron withdrawing groups could be used regardless of their substituted position, to give the corresponding 3a,8adihydroindeno [1,2d]imidazoles 2a-j in good to high yields (entries [1][2][3][4][5][6][7][8][9]. Surprisingly, the one-pot three-components reaction worked excellently for alkyl and allylic chlorides (entries [11][12][13][14] and their precipitated products 2k-n were separated in high yields. The precipitation of the products from the reaction medium not only caused by the development of a driving force for fast progress and completion of the reactions but also resulted in more efficient and rapid separation of pure products.…”

“…[7] Therefore, these derivatives have attracted considerable attention from both medicinal and synthetic chemists in recent years. [8][9][10][11][12][13] Imidazole and its derivatives have broad therapeutic applications, [14] and incorporated into many important biologically and pharmaceutically active molecules. [15,16] Their biological activities could also be improved if they joined to other heterocyclic compounds.…”

Synthesis of Heteroarene‐Fused Cyclopentadienes and Related Compounds Suitable for Metallocene Preparation

“…[174] The best yields of 263 and 4methyl derivative 265 were obtained from the accessible starting compound cyclopentane-1,3-dione using a Pd-catalyzed Heck reaction. [175,176] 1-Phenyl-1,2-dihydrocyclopenta[b]indol-3(4H)-one 266 was prepared by the Wittig reaction of the Nprotected anhydride of 1H-indole-2,3-dicarboxylic acid followed by Nazarov cyclization (Scheme 43). [177] The Nazarov cyclization of a number indolyl vinyl ketones was also studied by Bergman et al [178] Cycliza-Scheme 40.…”

“…Preparation of 2,3-dihydrocyclopenta[b]indol-1 (4H)-ones. [172,173,175,176] Scheme 43. Synthesis of 1-phenyl-1,2-dihydrocyclopenta[b]indol-3(4H)-one.…”

Design, synthesis, and molecular docking of new 5-HT reuptake inhibitors based on modified 1,2-dihydrocyclopenta[b]indol-3(4H)-one scaffold

“…The first step in designing a new bioactive molecule is the synthetic pathway, which allows easy and efficient preparation of the compound. The scaffold containing the indole moiety fused with an alicyclic ring might be formed in a few different ways, including Fisher indolization, 34 oxidative cyclizations of arylenaminones, 35 Heck-type cyclizations, 36 reductive cyclizations, 37 or Friedel-Crafts acylation. 38 Retrosynthetic analysis (Scheme 2) led us to assume that the desired key intermediate 1-aryl-1,2-dihydrocyclopenta [b]indol-3(4H)-one (5) might be easily formed through intramolecular Friedel-Crafts acylation.…”