Iodine-catalyzed conjugate addition of indoles onto en-1,4-dione: A novel synthesis of 3-(1-(1H-indol-3-yl)-2-oxo-2-phenylethyl)indolin-2-ones as antibacterial and antifungal agents

TfOH-Catalyzed One-Pot Domino Reaction for Diastereoselective Synthesis of Polysubstituted Tetrahydrospiro[carbazole-1,3′-indoline]s

“…Initially, the reaction conditions were examined by using 1-methylindole, acetophenone, and ethyl ( E )-2-(1-benzyl-5-chloro-2-oxoindolin-3-ylidene)­acetate as a standard . When the three-component reaction was carried out in the presence of TsOH and TfOH, 1-methylindole was quickly added to 3-methyleneoxindoline to give the known Michael addition product in high yield . To prevent the formation of this Michael addition product, 1-methylindole first reacted with acetophenone in toluene in the presence of TfOH.…”

“…We were pleased to find that they have the same relative configuration, in which the aryl group, ethoxycarboxyl, exists in the cis -position and the phenyl group of the oxindoline moiety stands at the trans -configuration. It should be pointed out that the ethoxycarbonyl group and the phenyl group of the oxindoline moiety usually exist at the cis -position in the starting ethyl ( E )-2-(2-oxoindolin-3-ylidene)­acetates . Thus, the formation of a trans -configuration for these two groups in the obtained tetrahydrospiro­[carbazole-1,3′-indoline]­s 1a – 1l suggested that the reaction contained a more complicated cyclization process rather than the expected concerted Diels–Alder reaction, which would afford the tetrahydrospiro­[carbazole-1,3′-indoline]­s 1a – 1l with a cis -configuration …”

Selective Synthesis of 3-(9H-Carbazol-2-yl)indolin-2-ones and Spiro[tetrahydrocarbazole-3,3′-oxindoles] via a HOTf Catalyzed Three-Component Reaction

“…14 In order to shed more light on the proposed reaction mechanism, further control experiments were carried out (Scheme 2). At first, the HOTf catalyzed reaction of 3phenacylideneoxindoles (X = H, Cl) with 1-methylindole in toluene in less than 10 min not only gave the known Michael adducts 7a and 7b in good yields 17 but also afforded other kind of products, 8a and 8b, in lower yields. The reaction of the initially prepared compounds, 7a, 7b, 8a, and 8b, with an excess of acetophenone in toluene in the presence of HOTf afforded the carbazole derivatives 4a and 4b in high yields (eq 4 in Scheme 2).…”

Synthesis, characterization and cytotoxic investigations of novel bis(indole) analogues besides antimicrobial study

“…In particular, C-3-substituted indoles are important building blocks for the synthesis of many biologically active compounds which possess antimalarial (Agarwal et al, 2005), inhibitors of HIV-1 (Meanwell et al, 2009), antimicrobial (Lakshmi et al, 2010;Reddy et al, 2011), antioxidant (Lakshmi et al, 2010), anticancer (Lakshmi et al, 2010), cytotoxic (Gu et al, 1999), inhibitors of hepatitis C virus (Jin et al, 2014), anti-diabetic (Rajesh et al, 2007), and neuro protective (Mohareb et al, 2011) activities. On the other hand, N-1 and C-3-substituted indole derivatives have been found to play an important role in many biologically active compounds especially with antiinflammatory (Hall et al, 2008;Singh et al, 2008), anticancer (Singh et al, 2008;Madadi et al, 2014), anti-nociceptive (Adam et al, 2010) and antipsychotic (Madadi et al, 2013) activities.…”