Novel 5-substituted 2,4-thiazolidinedione and 2,4-oxazolidinedione derivatives as insulin sensitizers with antidiabetic activities

Elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles using trifluoroacetic anhydride as reagent

An elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles from the reaction of acetophenone oxime acetates with trifluoroacetic anhydride is described.

N-Arylation of ferrocenyl 2,4-thiazolidinedione conjugatesviaa copper-catalysed Chan–Lam cross coupling reaction with aryl boronic acids and their optoelectronic properties

Copper catalysed Chan–LamN-arylation of ferrocenyl 2,4-thiazolidinedione conjugates is described.

Transition-metal-free synthesis of oxazoles: valuable structural fragments in drug discovery

This review article encapsulates the recent developments in the metal-free approaches used to construct oxazole moiety.

Novel rhodanines with anticancer activity: design, synthesis and CoMSIA study

A library of novel rhodanines are reported for their anticancer activity along with the 3D QSAR.

Fe-catalyzed synthesis of substituted N-aryl oxazolidines

An unprecedented Fe-catalyzed oxazolidine formation was observed from the reaction of allyl alcohols with arylhydroxylamines in presence of formaldehyde or its equivalents.

Prospective QSAR-Based Prediction Models with Pharmacophore Studies of Oxadiazole-Substituted α-Isopropoxy Phenylpropanoic Acids with Dual Activators of PPARα and PPARγ

A series of oxadiazole-substituted [Formula: see text]-isopropoxy phenylpropanoic acids with dual activators of PPARα and PPARγ derivatives were subjected to two-dimensional and k-Nearest Neighbors molecular field analysis. The statistically significant best 2D-QSAR (PPARα ) model having good predictive ability with statistical values of r(2) = 0:8725; q(2) = 0:7957and pred_r(2) = 0:8136 was developed by GA-PLS with the descriptors like SsClcount, SddsN (nitro) count and SsOHcount that contribute significantly to the biological activity. The best 3D-QSAR studies (PPARα ) were performed using the genetic algorithm selection k-nearest neighbor molecular field analysis approach; a leave-one-out cross-validated correlation coefficient q(2) = 0:7188 and predicate activity pred_r(2) = 0.7508 were obtained. The influences of steric and electrostatic field effects generated by the contribution plots are discussed. The best pharmacophore model includes three features, viz. hydrogen bond donor, hydrogen bond acceptor and aromatic features. The information rendered by 2D-QSAR and 3D-QSAR models may lead to a better understanding of structural requirements of substituted α-isopropoxy phenylpropanoic derivatives and also aid in designing novel potent PPARα and PPARγ for antihyperglycemic molecules.

Design, synthesis, and anti-inflammatory evaluation of novel diphenylthiazole-thiazolidinone hybrids

A series of diphenylthiazole-thiazolidinone hybrids was synthesized and evaluated in vitro and in vivo as anti-inflammatory/analgesic agents. The inhibition of cyclooxygenase (COX) enzymes was suggested as a molecular mechanism for the hybrids to exert their anti-inflammatory action. Of these compounds, 13b, 14, and 15b showed the most potent COX inhibitory activity with IC50 values between 2.03 and 12.27 µM, but with different selectivity profiles. All compounds were further evaluated in vivo for their anti-inflammatory/analgesic activities using three animal models. Interestingly, the results of the COX assay were in agreement with those of in vivo assays where the most potent COX inhibitors, 13b, 14, and 15b, exhibited the highest anti-inflammatory/analgesic activities compared to diclofenac. On the contrary, compounds 11 and 12 were the least potent ligands in vitro and in vivo as well.

Iodine catalysed intramolecular C(sp3)–H functionalization: synthesis of 2,5-disubstituted oxazoles from N-arylethylamides

Iodine catalyzed synthesis of 2,5-substituted oxazoles from N-arylethylamides through intramolecular C(sp³)–H functionalization under metal-free conditions is described.

Synthesis of oxazolidine-2,4-diones by a tandem phosphorus-mediated carboxylative condensation–cyclization reaction using atmospheric carbon dioxide

A novel access to oxazolidine-2,4-diones using atmospheric CO₂ and readily available substrates under mild and transition-metal-free conditions is developed.

Copper-catalyzed oxidative cyclization of arylamides and β-diketones: new synthesis of 2,4,5-trisubstituted oxazoles

Various 2,4,5-trisubstituted oxazoles were prepared from benzamides and β-diketones using CuBr as the sole catalyst.

Prospective QSAR-based prediction models with pharmacophore studies of oxadiazole-substituted α-isopropoxy phenylpropanoic acids on with dual activators of PPARα and PPARγ

A series of oxadiazole-substituted α-isopropoxy phenylpropanoic acids with dual activators of PPARα and PPARγ derivatives were subjected to two dimensional and k-nearest neighbour Molecular field analysis. The statistically significant best 2D-QSAR (PPARα) model having good predictive ability with statistical values of r2 = 0.8725, q2 = 0.7957 and pred_r2 = 0.8136, was developed by GA-PLS with the descriptors like SsClcount, SddsN (nitro) count and SsOHcount contribute significantly to the biological activity. The best 3D-QSAR studies (PPARα) were performed using the genetic algorithm selection k-nearest neighbor molecular field analysis approach; a leave-one-out cross-validated correlation coefficient q2=0.7188 and predicate activity pred_r2 =0.7508 were obtained. The influences of steric and electrostatic field effects generated by the contribution plots are discussed. The best pharmacophore model includes three features viz. hydrogen bond donor, hydrogen bond acceptor, and aromatic features were developed. The information rendered by 2D, 3D QSAR models may lead to a better understanding of structural requirements of substituted α-isopropoxy phenylpropanoic derivatives and also aid in designing novel potent PPARα and PPARγ for antihyperglycemic molecules.

Synthesis of substituted oxazoles from enamides

2,5- and 2,4,5-substituted oxazoles were prepared in one-pot by the NBS/Me₂S-mediated cyclization of enamides in the presence of base.

SAR and Computer-Aided Drug Design Approaches in the Discovery of Peroxisome Proliferator-Activated Receptor γ Activators: A Perspective

Activators of PPARγ, Troglitazone (TGZ), Rosiglitazone (RGZ), and Pioglitazone (PGZ) were introduced for treatment of Type 2 diabetes, but TGZ and RGZ have been withdrawn from the market along with other promising leads due cardiovascular side effects and hepatotoxicity. However, the continuously improving understanding of the structure/function of PPARγ and its interactions with potential ligands maintain the importance of PPARγ as an antidiabetic target. Extensive structure activity relationship (SAR) studies have thus been performed on a variety of structural scaffolds by various research groups. Computer-aided drug discovery (CADD) approaches have also played a vital role in the search and optimization of potential lead compounds. This paper focuses on these approaches adopted for the discovery of PPARγ ligands for the treatment of Type 2 diabetes. Key concepts employed during the discovery phase, classification based on agonistic character, applications of various QSAR, pharmacophore mapping, virtual screening, molecular docking, and molecular dynamics studies are highlighted. Molecular level analysis of the dynamic nature of ligand-receptor interaction is presented for the future design of ligands with better potency and safety profiles. Recently identified mechanism of inhibition of phosphorylation of PPARγ at SER273 by ligands is reviewed as a new strategy to identify novel drug candidates.

Solvent-catalyzed ring-chain-ring tautomerization in axially chiral compounds

The mechanism of ring-chain-ring tautomerization and the prominent effect of the solvent environment have been computationally investigated in an effort to explain the enantiomeric interconversion observed in 2-oxazolidinone derivatives, heterocyclic analogues of biphenyl atropisomers, which were isolated as single stable enantiomers and have the potential to be used as axially chiral catalysts. This study has shed light on the identity of the intermediate species involved in the ring-chain-ring tautomerization process as well as the catalytic effect of polar protic solvents. These mechanistic details will prove very useful in predicting and understanding ring-chain tautomeric equilibria in similar heterocyclic systems and will further enable experimentalists to devise appropriate experimental conditions in which axially chiral catalysts remain stable as single enantiomers.

Room temperature copper(II)-catalyzed oxidative cyclization of enamides to 2,5-disubstituted oxazoles via vinylic C-H functionalization

A copper(II)-catalyzed oxidative cyclization of enamides to oxazoles via vinylic C-H bond functionalization at room temperature is described. Various 2,5-disubstituted oxazoles bearing aryl, vinyl, alkyl, and heteroaryl substituents could be synthesized in moderate to high yields. This reaction protocol is complementary to our previously reported iodine-mediated cyclization of enamides to afford 2,4,5-trisubstituted oxazoles.

5-(4-Hydroxy-2,3,5-trimethylbenzylidene) thiazolidine-2,4-dione attenuates atherosclerosis possibly by reducing monocyte recruitment to the lesion

A variety of benzylidenethiazole analogs have been demonstrated to inhibit 5-lipoxygenase (5-LOX). Here we report the anti-atherogenic potential of 5-(4-hydroxy- 2,3,5-trimethylbenzylidene) thiazolidin-2,4-dione (HMB-TZD), a benzylidenethiazole analog, and its potential mechanism of action in LDL receptor-deficient (Ldlr-/-) mice. HMB-TZD Treatment reduced leukotriene B4 (LTB4) production significantly in RAW264.7 macrophages and SVEC4-10 endothelial cells. Macrophages or endothelial cells pre-incubated with HMB-TZD for 2 h and then stimulated with lipopolysaccharide or tumor necrosis factor-alpha (TNF-α) displayed reduced cytokine production. Also, HMB-TZD reduced cell migration and adhesion in accordance with decreased proinflammatory molecule production in vitro and ex vivo. HMB-TZD treatment of 8-week-old male Ldlr-/- mice resulted in significantly reduced atherosclerotic lesions without a change to plasma lipid profiles. Moreover, aortic expression of pro-atherogenic molecules involved in the recruitment of monocytes to the aortic wall, including TNF-α , MCP-1, and VCAM-1, was downregulated. HMB-TZD also reduced macrophage infiltration into atherosclerotic lesions. In conclusion, HMB-TZD ameliorates atherosclerotic lesion formation possibly by reducing the expression of proinflammatory molecules and monocyte/macrophage recruitment to the lesion. These results suggest that HMB-TZD, and benzylidenethiazole analogs in general, may have therapeutic potential as treatments for atherosclerosis.

Synthesis of tryptoline-3-carboxylic Acid derivatives a novel antidiabetic agent

The compounds, 2-(methylsulfonyl)-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid (DM3), 2-(phenylsulfonyl)-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid (DM₄), and 2-(p-toluenesulfonyl)-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid (DM₅) were synthesized by coupling of 1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid (DM₂) with methanesulfonyl chloride, benzenesulfonyl chloride, and toluenesulfonyl chloride, which in turn, was synthesized by dissolving dilute aqueous ammonia with 2-(N-hydroxy methyl amino)-indol-3-yl-propanoic acid (DM₁) which is the reaction product of l-tryptophan and formalin. All the intermediates and title compounds were characterized by physical, chemical, analytical, and spectral data. All the title compounds have been screened for in vivo antidiabetic activity in streptozotocin-induced diabetic rats, and serum glucose was estimated spectrophotometrically at 505 nm by glucose oxidase/peroxidase method. Compound DM₅ showed potent antidiabetic activity.

Anti-atherogenic effect of BHB-TZD having inhibitory activities on cyclooxygenase and 5-lipoxygenase in hyperlipidemic mice

Cyclooxygenase (COX) and 5-lipoxygenase (5-LOX), which play pivotal roles in atherogenesis, have been reported to be involved in plaque stability. Licofelone, a dual COX and 5-LOX inhibitor, has been reported to possess anti-atherogenic effect in rabbit atherosclerosis model. We therefore investigated the anti-atherogenic effect of BHB-TZD [5-(3,5-di-tert-butyl-4-hydroxybenzylidene)thiazolidin-2,4-dione], a dual COX and 5-LOX inhibitor, in low density lipoprotein receptor null (LDLR-/-) mice. Fifteen LDLR-/- mice were fed a western diet (control group), whereas 15 were fed a western diet plus 0.1% (w/w) BHB-TZD (BHB-TZD group). After 8 weeks, the BHB-TZD group had markedly lower serum levels of leukotriene B(4) and prostaglandin E(2) than the control group. Interestingly, BHB-TZD treatment also reduced plasma triglyceride level without significant changes in total cholesterol and HDL levels. Compared with control mice, BHB-TZD fed mice had 52% fewer fatty streak lesions in the aortic sinus, as well as fewer initial lesions in the aortic arch. Macrophage infiltration into the lesions was 40% lower, and collagen and smooth muscle cells were increased by 102% and 96%, respectively, in the BHB-TZD group compared with the control group. In addition, aortic expression of proatherogenic molecules including TNF-alpha, IL-1beta, IL-6, MCP-1 and VCAM-1, was lower in the BHB-TZD group than the control group. BHB-TZD treatment also reduced MMP-2 and MMP-9 expressions in aorta. In conclusion, BHB-TZD effectively attenuated atherosclerosis in mouse model, suggesting its therapeutic potential for atherosclerosis.

Synthesis of new imidazolidin-2,4-dione and 2-thioxoimidazolidin-4-ones via C-phenylglycine derivatives

Hydantoins and their derivatives constitute a group of pharmaceutical compounds with anticonvulsant and antiarrhythmic properties, and are also used against diabetes. N-3 and C-5 substituted imidazolidines are examples of such products. As such, we have developed a synthesis of 2,4-dione and 2-thioxo-4-one imidazolidinic derivatives by reaction of amino acids with C-phenylglycine, phenyl isocyanate and phenyl isothiocyanate. Four amino-derivatives IG(1-4) and eight imidazolidinic derivatives, IM(1-8), were obtained in yields of 70–74%. The mass, infrared, ¹H and ¹³C-NMR spectra of representative products are discussed.

Structure-activity relationship (SAR) studies of 3-(2-amino-ethyl)-5-(4-ethoxy-benzylidene)-thiazolidine-2,4-dione: development of potential substrate-specific ERK1/2 inhibitors

A series of analogs of 3-(2-amino-ethyl)-5-(4-ethoxy-benzylidene)-thiazolidine-2,4-dione, a putative substrate-specific ERK1/2 inhibitor, were synthesized and biologically characterized in human leukemia U937 cells to define its pharmacophore. It was discovered that shift of ethoxy substitution from the 4- to the 2-position on the phenyl ring significantly improved functional activities of inhibiting cell proliferation and inducing apoptosis. This may provide access to a new lead for developing ERK1/2 substrate-specific inhibitors.

Electrophilic alpha-thiocyanation of chiral and achiral N-acyl imides. A convenient route to 5-substituted and 5,5-disubstituted 2,4-thiazolidinediones

Electrophilic alpha-thiocyanation of N-acyl carboximides using N-thiocyanatosuccinimide and hydrolytic cyclization of the adducts affords 5-substituted and 5,5-disubstituted 2,4-thiazolidinediones in good overall yields. Alpha-thiocyanation of chiral N-acyl carboximides proceeds with excellent diastereoselectivity, although partial racemization occurs during subsequent cyclization.

Design and synthesis of 6-methyl-2-oxo-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid derivatives as PPARγ activators

The design and synthesis of novel series of 6-methyl-2-oxo-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid (pyrimidone) derivatives that are high affinity ligands for peroxisome proliferators activated receptor gamma have been reported as a potential substitute of 2,4-thiazolidinedione head group. The FlexX docking and radioligand binding affinity of some promising compounds of this series is comparable to that of thiazolidinedione based antidiabetic drugs currently in clinical use.