Research

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11 pages, 1404 KiB

Open AccessArticle

The Generation of Indole-2,3-quinodimethanes from the Deamination of 1,2,3,4-Tetrahydropyrrolo[3,4-b]indoles

by Alison Rinderspacher and Gordon W. Gribble

Molecules 2020, 25(2), 261; https://doi.org/10.3390/molecules25020261 - 09 Jan 2020

Cited by 7 | Viewed by 3576

A novel generation of indole-2,3-quinodimethanes via the deamination of 1,2,3,4-tetrahydropyrrolo[s3,4-b]indoles is reported. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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15 pages, 1728 KiB

Open AccessArticle

Synthesis of Bis-Glyoxylamide Peptidomimetics Derived from Bis-N-acetylisatins Linked at C5 by a Methylene or Oxygen Bridge

by Venty Suryanti, Ruonan Zhang, Vina Aldilla, Mohan Bhadbhade, Naresh Kumar and David StC Black

Molecules 2019, 24(23), 4343; https://doi.org/10.3390/molecules24234343 - 27 Nov 2019

Cited by 3 | Viewed by 2988

Abstract

The bis-glyoxylamide peptidomimetics have been synthesized from bis-N-acetylisatins linked at C5 by ring-opening with alcohols, amines, and amino acid methyl ester hydrochlorides. X-ray images of single crystals of bis-glyoxylamide peptidomimetics have been obtained. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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19 pages, 2406 KiB

Open AccessArticle

[b]-Annulated Halogen-Substituted Indoles as Potential DYRK1A Inhibitors

by Christian Lechner, Maren Flaßhoff, Hannes Falke, Lutz Preu, Nadége Loaëc, Laurent Meijer, Stefan Knapp, Apirat Chaikuad and Conrad Kunick

Molecules 2019, 24(22), 4090; https://doi.org/10.3390/molecules24224090 - 13 Nov 2019

Cited by 13 | Viewed by 3828

Abstract

Since hyperactivity of the protein kinase DYRK1A is linked to several neurodegenerative disorders, DYRK1A inhibitors have been suggested as potential therapeutics for Down syndrome and Alzheimer’s disease. Most published inhibitors to date suffer from low selectivity against related kinases or from unfavorable physicochemical [...] Read more.

Since hyperactivity of the protein kinase DYRK1A is linked to several neurodegenerative disorders, DYRK1A inhibitors have been suggested as potential therapeutics for Down syndrome and Alzheimer’s disease. Most published inhibitors to date suffer from low selectivity against related kinases or from unfavorable physicochemical properties. In order to identify DYRK1A inhibitors with improved properties, a series of new chemicals based on [b]-annulated halogenated indoles were designed, synthesized, and evaluated for biological activity. Analysis of crystal structures revealed a typical type-I binding mode of the new inhibitor 4-chlorocyclohepta[b]indol-10(5H)-one in DYRK1A, exploiting mainly shape complementarity for tight binding. Conversion of the DYRK1A inhibitor 8-chloro-1,2,3,9-tetrahydro-4H-carbazol-4-one into a corresponding Mannich base hydrochloride improved the aqueous solubility but abrogated kinase inhibitory activity. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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15 pages, 2009 KiB

Open AccessCommunication

Synthesis and Cyclooxygenase Inhibition of Sulfonamide-Substituted (Dihydro)Pyrrolo[3,2,1-hi]indoles and Their Potential Prodrugs

by Markus Laube, Cemena Gassner, Torsten Kniess and Jens Pietzsch

Molecules 2019, 24(20), 3807; https://doi.org/10.3390/molecules24203807 - 22 Oct 2019

Cited by 12 | Viewed by 3306

Abstract

Non-invasive imaging of cyclooxygenase-2 (COX-2) by radiolabeled ligands is attractive for the diagnosis of cancer, and novel highly affine leads with optimized pharmacokinetic profile are of great interest for future developments. Recent findings have shown that methylsulfonyl-substituted (dihydro)pyrrolo[3,2,1-hi]indoles represent highly potent [...] Read more.

Non-invasive imaging of cyclooxygenase-2 (COX-2) by radiolabeled ligands is attractive for the diagnosis of cancer, and novel highly affine leads with optimized pharmacokinetic profile are of great interest for future developments. Recent findings have shown that methylsulfonyl-substituted (dihydro)pyrrolo[3,2,1-hi]indoles represent highly potent and selective COX-2 inhibitors but possess unsuitable pharmacokinetic properties for radiotracer applications. Based on these results, we herein present the development and evaluation of a second series of sulfonamide-substituted (dihydro)pyrrolo[3,2,1-hi]indoles and their conversion into the respective more hydrophilic N-propionamide-substituted analogs. In comparison to the methylsulfonyl-substituted leads, COX inhibition potency and selectivity was retained in the sulfonamide-substituted compounds; however, the high lipophilicity might hinder their future use. The N-propionamide-substituted analogs showed a significantly decreased lipophilicity and, as expected, lower or no COX-inhibition potency. Hence, the N-(sulfonyl)propionamides can be regarded as potential prodrugs, which represents a potential approach for more sophisticated radiotracer developments. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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15 pages, 5920 KiB

Open AccessArticle

Sequential Annulations to Interesting Novel Pyrrolo[3,2-c]carbazoles

by Alice Benzi, Lara Bianchi, Massimo Maccagno, Angela Pagano, Giovanni Petrillo and Cinzia Tavani

Molecules 2019, 24(20), 3802; https://doi.org/10.3390/molecules24203802 - 22 Oct 2019

Cited by 10 | Viewed by 2339

Abstract

Herein we report a significant, valuable extension of a recently implemented pyrrole benzannulation methodology that, employing versatile nitrodienes from our lab as useful C₄ building blocks, led to indole derivatives characterized by unusual patterns of substitution. The 6-nitro-7-arylindoles resulting from suitably derivatized, [...] Read more.

Herein we report a significant, valuable extension of a recently implemented pyrrole benzannulation methodology that, employing versatile nitrodienes from our lab as useful C₄ building blocks, led to indole derivatives characterized by unusual patterns of substitution. The 6-nitro-7-arylindoles resulting from suitably derivatized, non-symmetric dienes are of foreseeable synthetic interest in search for new polyheterocyclic systems. As an example, pyrrolocarbazoles with a rarely reported ring fusion were synthesized with the classical Cadogan protocol. Furthermore, the proven easy reducibility of the nitro group to amine will surely open the way to further interesting elaborations. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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15 pages, 4846 KiB

Open AccessArticle

Synthesis and Density Functional Theory Studies of Azirinyl and Oxiranyl Functionalized Isoindigo and (3Z,3’Z)-3,3’-(ethane-1,2-diylidene)bis(indolin-2-one) Derivatives

by Gholamhossein Khalili, Patrick M. McCosker, Timothy Clark and Paul A. Keller

Molecules 2019, 24(20), 3649; https://doi.org/10.3390/molecules24203649 - 10 Oct 2019

Cited by 2 | Viewed by 2834

Abstract

The design and synthesis of functionalized isoindigo compounds by reaction of isoindigo with (S)-glycidyl tosylate, epibromohydrin, 2-(bromomethyl)-1-(arylsulfonyl)aziridine, and 2-(bromomethyl)-1-(alkylsulfonyl)aziridine in the presence of MeONa proceed under mild conditions in moderate yields. (3Z,3’Z)-3,3’-(Ethane-1,2-diylidene)bis(1-(oxiran-2-ylmethyl)indolin-2-one), with an extended central olefin [...] Read more.

The design and synthesis of functionalized isoindigo compounds by reaction of isoindigo with (S)-glycidyl tosylate, epibromohydrin, 2-(bromomethyl)-1-(arylsulfonyl)aziridine, and 2-(bromomethyl)-1-(alkylsulfonyl)aziridine in the presence of MeONa proceed under mild conditions in moderate yields. (3Z,3’Z)-3,3’-(Ethane-1,2-diylidene)bis(1-(oxiran-2-ylmethyl)indolin-2-one), with an extended central olefin π-conjugated moiety was also reacted with methyl-oxiranes to give the corresponding N,N’-disubstituted derivative. Calculations with DFT and TD-DFT of hypothetical isoindigo-thiophene DA molecules with various electron withdrawing substituents, including aziridine, oxirane, nitrile, carbonyl, and sulfonate, indicated that the proximity and strength of the functional group have a significant effect on the HOMO, LUMO, vertical excitation energy, and oscillator strength of the π–π* transitions. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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20 pages, 4068 KiB

Open AccessArticle

Spiroindolone Analogues as Potential Hypoglycemic with Dual Inhibitory Activity on α-Amylase and α-Glucosidase

by Mezna Saleh Altowyan, Assem Barakat, Abdullah Mohammed Al-Majid and H.A. Al-Ghulikah

Molecules 2019, 24(12), 2342; https://doi.org/10.3390/molecules24122342 - 25 Jun 2019

Cited by 24 | Viewed by 3780

Abstract

Inhibition of α-amylase and α-glucosidase by specified synthetic compounds during the digestion of starch helps control post-prandial hyperglycemia and could represent a potential therapy for type II diabetes mellitus. A new series of spiroheterocyclic compounds bearing oxindole/benzofuran/pyrrolidine/thiazolidine motifs were synthesized via a 1,3-dipolar [...] Read more.

Inhibition of α-amylase and α-glucosidase by specified synthetic compounds during the digestion of starch helps control post-prandial hyperglycemia and could represent a potential therapy for type II diabetes mellitus. A new series of spiroheterocyclic compounds bearing oxindole/benzofuran/pyrrolidine/thiazolidine motifs were synthesized via a 1,3-dipolar cyclo-addition reaction approach. The specific compounds were obtained by reactions of chalcones having a benzo[b]furan scaffold (compounds 2a–f), with a substituted isatin (compounds 3a–c) and heterocyclic amino acids (compounds 4a,b). The target spiroindolone analogues 5a–r were evaluated for their potential inhibitory activities against the enzymes α-amylase and α-glucosidase. Preliminary results indicated that some of the target compounds exhibit promising α-amylase and α-glucosidase inhibitory activity. Among the tested spiroindolone analogues, the cycloadduct 5r was found to be the most active (IC₅₀ = 22.61 ± 0.54 μM and 14.05 ± 1.03 μM) as α-amylase and α-glucosidase inhibitors, with selectivity indexes of 0.62 and 1.60, respectively. Docking studies were carried out to confirm the binding interaction between the enzyme active site and the spiroindolone analogues. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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Review

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46 pages, 24189 KiB

Open AccessReview

Indolylboronic Acids: Preparation and Applications

by Marek Čubiňák, Tereza Edlová, Peter Polák and Tomáš Tobrman

Molecules 2019, 24(19), 3523; https://doi.org/10.3390/molecules24193523 - 28 Sep 2019

Cited by 9 | Viewed by 7493

Abstract

Indole derivatives are associated with a variety of both biological activities and applications in the field of material chemistry. A number of different strategies for synthesizing substituted indoles by means of the reactions of indolylboronic acids with electrophilic compounds are considered the methods [...] Read more.

Indole derivatives are associated with a variety of both biological activities and applications in the field of material chemistry. A number of different strategies for synthesizing substituted indoles by means of the reactions of indolylboronic acids with electrophilic compounds are considered the methods of choice for modifying indoles because indolylboronic acids are easily available, stable, non-toxic and new reactions using indolylboronic acids have been described in the literature. Thus, the aim of this review is to summarize the methods available for the preparation of indolylboronic acids as well as their chemical transformations. The review covers the period 2010–2019. Full article

(This article belongs to the Special Issue Indole Derivatives: Synthesis and Application)

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