3-Aryl β-carbolin-1-ones as a new class of potent inhibitors of tumor cell proliferation: synthesis and biological evaluation

Synthesis of 2,3-Disubstituted 4-Ethoxycarbonyl-β-carbolin-1-ones: Application to the Synthesis of SL651498 and Its Analogue

Synthesis of 2,3-disubstituted 4-ethoxycarbonyl-β-carbolin-1-ones is developed using palladium-catalyzed intramolecular amination of 3-amino-4-(2-bromophenyl)-2-pyridones prepared by the conjugate addition reaction of diethyl 2-aminomalonate to alkynyl imines. The method was applied to the total syntheses of SL651498 exhibiting anxiolytic activity and its analogue.

Reactivity of alkynylindole-2-carboxamides in [Pd]-catalysed C–H activation and phase transfer catalysis: formation of pyrrolo-diindolones vs. β-carbolinones

[Pd]-Catalysed reaction of 3-alkynylindole-2-carboxamidesviaC–H activation leads to pyrrolodiindolones; in contrast, under phase-transfer catalysis, the same precursors afford β-carbolinones.

Oxidative C(sp3)–H functionalization of acetonitrile and alkanes with allylic alcohols under metal-free conditions

Direct oxidative C(sp³)–H functionalization of acetonitrile and alkanes with α,α-diaryl allylic alcohols has been developed.

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed Buchwald-Hartwig-type reactions, copper-mediated Ullmann-type and Chan-Lam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than Chan-Lam reactions. Chan-Lam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and Buchwald-Hartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired C-N bond formation in the course of a total synthesis or drug synthesis.

The gramine route to pyrido[4,3-b]indol-3-ones - identification of a new cytotoxic lead

A novel approach to 3-oxo-γ-carbolines was worked out starting from methyl indol-2-ylacetate via a gramine derivative. After quaternization, ammonia and 4-methoxybenzylamine could be inserted giving appropriate 3-oxo-γ-carbolines. Condensation with 2-chlorobenzaldehyde under microwave irradiation gave a 4-(2-chlorobenzyl)-3-oxo-γ-carboline. N-methylation lead to a product with very promising antifungal and cytotoxic activities.

CR229, a novel derivative of beta-carbolin-1-one, induces cell cycle arrest and apoptosis in HeLa cells via p53 activation

In the course of screening for novel anticancer compounds, CR229 (6-Bromo-2,3,4,9-tetrahydro-carbolin-1-one), a novel derivative of beta-carbolin-1-one, was generated as a new scaffold candidate. For the first time, the authors demonstrate that CR229 inhibited the growth of HeLa cells by the induction of cell cycle arrest and apoptosis. Analysis of flow cytometry and western blots of HeLa cells treated with 2.5 microM CR229 revealed an appreciable cell cycle arrest in the G1, G2/M phase and apoptotic induction via the p53-dependent pathway. Furthermore, the release of cytochrome c from mitochondria was detected using confocal microscopy in HeLa cells treated with CR229. Accordingly, these data demonstrate that the anticancer activity of CR229 is associated with: (i) the down-regulation of cyclins and cyclin-dependent kinase; (ii) the induction of p53, p21, and p16; and (iii) the activation of caspase-3.

Stereoselective Quaternization of α-Amino Phenylacetonitriles Mediated by a Remote Sulfinyl Group

Enantiomerically pure alpha-substituted alpha-amino phenylacetonitriles have been readily prepared from 2-p-tolylsulfinylbenzaldimines following a two-step sequence: a moderately stereoselective hydrocyanation of the imines and a completely stereoselective quaternization of the resulting diastereoisomeric mixture of alpha-amino phenylacetonitriles with different alkylating or acylating reagents in the presence of KHMDS. Theoretical calculations support a stereoselectivity control exerted by the remote sulfinyl group, as long as it is responsible for the conformational preferences of the benzyllithium intermediates, which suffer the attack of the electrophiles to the less hindered diastereotopic face.