Efficient solid-phase synthesis of 2-substituted-3-hydroxy-4(1H)-quinolinone-7-carboxamides with two diversity positions

Phosphine-Mediated Redox Cyclization of 1-(2-Nitroaryl)prop-2-ynones to 3-Hydroxyquinolin-4-ones: Formal Intramolecular Oxyamination of α,β-Ynones

3-Hydroxyquinoline-4(1H)-ones (3HQs) are privileged structural motifs. The current methods for their synthesis necessitate strongly acidic or basic conditions, which hamper the generality and practicality. Here, we describe phosphine-mediated redox transformation of easily accessible 1-(2-nitroaryl)prop-2-ynones to 3HQs. Besides establishing a new entry to the synthesis of 3HQs under neutral conditions, this method is the first formal intramolecular oxyamination of α,β-ynones. The synthetic utility of this method is demonstrated in the total synthesis of japonine, its analogs, and rare quinoline derivatives.

Polymer-supported synthesis of N-substituted anthranilates as the building blocks for preparation of N-arylated 3-hydroxyquinolin-4(1H)-ones

Fast and simple access to N-arylated 3-hydroxyquinolin-4(1H)-ones starting from easily available 1-methyl-2-iodoterephthalate and variously substituted anilines is presented. N-Alkylated anthranilic acid derivatives represent important intermediates. They can be advantageously prepared by solid-phase synthesis, by Buchwald–Hartwig amination or reductive amination with wide substrate scope and with excellent crude purities.

Fast and simple access to N-arylated 3-hydroxyquinolin-4(1H)-ones starting from easily available 1-methyl-2-iodoterephthalate and variously substituted anilines is presented.

Identification of Eukaryotic Translation Elongation Factor 1-α 1 Gamendazole-Binding Site for Binding of 3-Hydroxy-4(1 H)-quinolinones as Novel Ligands with Anticancer Activity

Here, we have identified the interaction site of the contraceptive drug gamendazole using computational modeling. The drug was previously described as a ligand for eukaryotic translation elongation factor 1-α 1 (eEF1A1) and found to be a potential target site for derivatives of 2-phenyl-3-hydroxy-4(1 H)-quinolinones (3-HQs), which exhibit anticancer activity. The interaction of this class of derivatives of 3-HQs with eEF1A1 inside cancer cells was confirmed via pull-down assay. We designed and synthesized a new family of 3-HQs and subsequently applied isothermal titration calorimetry to show that these compounds strongly bind to eEF1A1. Further, we found that some of these derivatives possess significant in vitro anticancer activity.

Solid-supported hydrazone of 4-(4'-formyl-3'-methoxyphenoxy)butyric acid as a new traceless linker for solid-phase synthesis

The use of a hydrazine derived from a backbone amide linker as a new hydrazone-based traceless linker for solid-phase organic synthesis is described. The stability of the linker was tested under various conditions, including treatment with acids, bases, and borohydrides. Final compounds can be released by selective cleavage using trimethylsilanolate. To demonstrate the versatility of the linker, the synthesis of a model compound under various reaction conditions was performed with good results.

Preparation of 2-phenyl-3-hydroxyquinoline-4(1H)-one-5-carboxamides as potential anticancer and fluorescence agents

A simple pathway leading to 3-hydroxyquinoline-4(1H)-one-5-carboxamides was developed. Target compounds were identified as potential anticancer agents and fluorescent labels.

2-phenylsubstituted-3-hydroxyquinolin-4(1H)-one-carboxamides: Structure-cytotoxic activity relationship study

A structure-activity relationship of some derivatives of 2-phenylsubstituted- 3-hydroxyquinolin-4(1H)-one-7-carboxamides was systematically studied using combinatorial solid-phase synthesis and in vitro cytotoxic activity screening on representative cancer lines. The effect of substituent type in position 2 as well as of the carboxamide group was investigated via synthesis of generic libraries constructed with respect to polarity and bulkiness of appropriate substituents. The process of development afforded a set of compounds with significant cytotoxic activity. Subsequently, corresponding 2-phenylsubstituted-3-hydroxyquinolin-4(1H)-one-6-carboxamides and 2-phenylsubstituted-3-hydroxyquinolin-4(1H)-one-8-carboxamides were prepared to evaluate the influence of the carboxamide group position on the resulting biological activity.

Polymer-supported alpha-acylamino ketones: preparation and application in syntheses of 1,2,4-trisubstituted-1H-imidazoles

Polymer-supported alpha-acylamino ketones were prepared from resin-bound amines, bromoketones, and carboxylic acids. Selective monoalkylation of amines by bromoketones was carried out via 4-nitrobenzenesulfonamides. There was a striking difference in the reaction outcome between 2-Nos and 4-Nos derivatives. Alpha-acylamino ketones were converted to imidazoles. The cyclization was performed on resin, allowing further polymer-supported elaboration of imidazoles including synthesis of bis-heterocyclic compounds. A small combinatorial array of imidazoles was synthesized. Target compounds were prepared under mild conditions using commercially available building blocks for the introduction of three points of diversity.

Efficient traceless solid-phase synthesis of 3,4-dihydropyrazino[1,2-b]indazoles and their 6-oxides

A highly efficient novel traceless solid-phase synthesis of 3,4-dihydropyrazino[1,2-b]indazoles and their 6-oxides was developed by using commercially available building blocks, diamines, 2-nitrobenzenesulfonyl chlorides, and bromoketones/bromoacetates. Mild reaction conditions, diversely substituted building blocks, and high purity of crude products enabled effective combinatorial syntheses of libraries.

Efficient solid-phase synthesis of 3-substituted-5-oxo-5H-thiazolo[2,3-b]-quinazoline-8-carboxamides under mild conditions with two diversity positions

Highly efficient solid-phase synthesis of thiazolo[2,3,b]quinazolines under mild conditions was developed using resin-bound 2-amino-terephthalamic acid, Fmoc-NCS, and bromoketones. Primary amines immobilized to an acid-cleavable backbone amide linker were acylated with 1-methyl-2-aminoterephtalate. Following cleavage of the methyl ester, Fmoc-NCS was used to form a resin-bound thiourea. Bromoketones were subsequently added to form an aminothiazole ring and the cyclization was performed using DIC/HOBt to afford thiazolo[2,3,b]quinazolines. Highly efficient solid-phase synthesis is amenable to high throughput/combinatorial synthesis.