Parallel Solution-Phase Synthesis of 2-Alkylthio-5-arylidene-3,5-dihydro-4H-imidazol-4-one by One-Pot Three-Component Domino Reaction

(Z)-2’-((Adamantan-1-yl)thio)-1,1’-dimethyl-2’,3’-dihydro-[2,4’-biimidazolylidene]-4,5,5’(1H,1’H,3H)-trione

The title compound, (Z)-2’-((adamantan-1-yl)thio)-1,1’-dimethyl-2’,3’-dihydro-[2,4’-biimidazolylidene]-4,5,5’(1H,1’H,3H)-trione, was found to be a by-product of the reaction of 1,3-dehydroadamantane with 3-methyl-2-thioxoimidazolidin-4-one and characterized via single-crystal X-ray diffraction.

The preparation of (4H)-imidazol-4-ones and their application in the total synthesis of natural products

(4H)-Imidazol-4-ones are an important scaffold for a variety of applications, including natural products, medicine, agriculture, and other applications. Over the years, there have been a number of preparations published for the synthesis of imidazol-4-ones. This review discusses the progress made on the synthesis of imidazol-4-ones, and their application towards the total synthesis of a range of imidazol-4-one containing natural products. Emphasis is made on areas of the field that still need progress.

Stereospecific Synthesis of ( E)-5-Tetrasubstituted-ylidene-3,5-dihydro-4 H-imidazol-4-ones

A stereospecific synthesis of ( E)-5-tetrasubstituted-ylidene-3,5-dihydro-4 H-imidazol-4-one derivatives is demonstrated through a cascade process by combination of a Michael addition and Boulton-Katritzky rearrangement. The method provides a simple and efficient approach for the synthesis of ( E)-5-tetrasubstituted-ylidene-3,5-dihydro-4 H-imidazol-4-ones from the reactions of N-(isoxazol-3-yl)-propiolamides or N-(1,2,4-oxadiazo-3-yl) propiolamides with N or C nucleophiles.

Unprecedented one-pot chemocontrolled entry to thioxoimidazolidinones and aminoimidazolones: synthesis of kinase inhibitor leucettamine B

A novel and highly chemoselective protocol for the construction of thioxoimidazolidinone and aminoimidazolone frameworks was explored, and the influence of the reaction conditions on product formation was studied to establish two distinct approaches for their selective formation. In this one-pot reaction, ambient temperature generally resulted in the formation of thioxoimidazolidinones, whereas microwave irradiation provided aminoimidazolones exclusively. An attempt to elucidate the observed chemoselectivity is described, and the products were confirmed by X-ray studies. One-pot synthesis toward Leucettamine B, a marine alkaloid, was achieved on the basis of this protocol.

Crystal structure of 8-[7,8-bis-(4-chloro-benzo-yl)-7H-cyclo-penta-[a]ace-naphthylen-9-yl]naphthalene-1-carb-oxy-lic acid

The title compound packs with a three-dimensional supra­molecular architecture via O—H⋯O, C—H⋯O and C—H⋯Cl hydrogen bonds and through C—H⋯π inter­actions.

The title compound, C₄₀H₂₂Cl₂O₄, was formed by a Michael–Aldol domino reaction sequence, which coupled acenaphthene­quinone with 4-chloro­aceto­phenone in the presence of KOH in methanol. The dihedral angles between the central cyclo­penta­[a]ace­naphthyl­ene fused-ring system (r.m.s. deviation = 0.066 Å) and the 4-chloro­benzoyl rings are 62.25 (10) and 70.19 (10)°. The dihedral angle between the central ring system and the naphthoic acid grouping is 62.46 (7)°. This twisting of the pendant rings facilitates the formation of an intra­molecular aromatic π–π stacking inter­action between the 4-chloro­benzoyl and naphthoic acid rings, with centroid–centroid distances of 3.4533 (16) and 3.5311 (16) Å, and a C—H⋯π inter­action between one of the H atoms of the central moiety and the 4-chloro­benzoyl ring with an H⋯π distance of 2.57 Å. In the crystal, carb­oxy­lic acid inversion dimers generate R₂²(8) loops. The dimers are linked by weak C—H⋯O and C—H⋯Cl hydrogen bonds and C—H⋯π inter­actions, generating a three-dimensional architecture.

Synthesis of N,N'-bis(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines bearing various linkers and biological evaluation as potential inhibitors of kinases

The synthesis in 4 steps of new N,N'-bis(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines issued from various symmetric primary diamines as linkers was reported. The key step of our strategy has been the sulphur/nitrogen displacement of (5Z)-5-arylidene-2-ethylsulfanyl-3,5-dihydro-4H-imidazol-4-ones 6 with respectively ethylenediamine 7a, piperazine 7b and N,N'-bis(3-aminopropyl)piperazine 7c using solvent-free reaction conditions under microwave irradiation with retention of configuration. These compounds were tested for their kinase inhibitory potencies toward four kinases (GSK-3α/β, DYRK1A, CLK1 and CLK3).

5-Arylidenethioxothiazolidinones as inhibitors of tyrosyl-DNA phosphodiesterase I

Tyrosyl-DNA phosphodiesterase I (Tdp1) is a cellular enzyme that repairs the irreversible topoisomerase I (Top1)-DNA complexes and confers chemotherapeutic resistance to Top1 inhibitors. Inhibiting Tdp1 provides an attractive approach to potentiating clinically used Top1 inhibitors. However, despite recent efforts in studying Tdp1 as a therapeutic target, its inhibition remains poorly understood and largely underexplored. We describe herein the discovery of arylidene thioxothiazolidinone as a scaffold for potent Tdp1 inhibitors based on an initial tyrphostin lead compound 8. Through structure-activity relationship (SAR) studies we demonstrated that arylidene thioxothiazolidinones inhibit Tdp1 and identified compound 50 as a submicromolar inhibitor of Tdp1 (IC₅₀ = 0.87 μM). Molecular modeling provided insight into key interactions essential for observed activities. Some derivatives were also active against endogenous Tdp1 in whole cell extracts. These findings contribute to advancing the understanding on Tdp1 inhibition.

A practical approach to new (5Z) 2-alkylthio-5-arylmethylene-1-methyl-1,5-dihydro-4H-imidazol-4-one derivatives

A practical protocol for the preparation of (5Z)-2-alkylthio-5-arylmethylene-1-methyl-1,5-dihydro-4H-imidazol-4-one derivatives is reported. The new compounds were obtained in good yield and stereoselectivity in two steps, namely a solvent-free Knoevenagel condensation under microwave irradiation, followed by an S-alkylation reaction with various halogenoalkanes.

Synthesis and preliminary biological evaluation of new derivatives of the marine alkaloid leucettamine B as kinase inhibitors

New derivatives of the marine alkaloid leucettamine B were prepared in five steps with overall yields ranging from 23 to 30%. The key step of our strategy has been the sulfur/nitrogen displacement under solvent-free microwave irradiation of (5Z) 5-benzo[1,3]-dioxo-5-ylmethylene-2-ethylsulfanyl-3,5-dihydroimidazol-4-one 3 with a mono-protected ethylenediamine 2. After deprotection of the N-Boc group, the amino derivative of leucettamine B 5 was subjected to reductive amination in two steps with retention of configuration of the double bond, to lead to eight new analogs of leucettamine B. The effect of these compounds on CK1alpha/beta, CDK5/p25, and GSK-3alpha/beta were investigated.

Soluble polymer-supported synthesis of 5-arylidene thiazolidinones and pyrimidinones using a novel traceless linker strategy

An efficient method for the soluble polymer-supported synthesis of 5-arylidene thiazolidinones and pyrimidinones using aniline as a traceless linker was described. Aldehyde substrates were attached to the polyethylene glycol (PEG)-bound aniline via an imine linkage, and after the subsequent PEG-promoted Suzuki coupling reaction for the diversification, Knoevenagel condensation was readily employed as the cleavage strategy.