Phthalimide Analogues Research Articles

Phthaloyl amino acids as anti-inflammatory and immunomodulatory prototypes

A series of phthalimide analogs were synthesized by derivatization of phthalic anhydride, a highly toxic substance, using a “one pot” condensation reaction to α-amino acids. All phthaloyl amino acid derivatives presented anti-oral inflammatory activity, but compounds 2e and 2g were found to possess the best activities comparable to thalidomide. Most of the compounds effectively suppressed nitric oxide production in murine cells stimulated with lipopolysaccharide. N-phthaloyl amino acids did not exhibit any significant cytotoxicity in vitro when tested against tumor cells as well as a spleen cell culture of BALB/c mice. Compounds 2a, 2g, and 2h were able to inhibit TNF-α and IL-1β production by macrophages. At the same concentration, thalidomide did not exhibit significant inhibitory activity. [The pharmacological evaluation of eight N-phthaloyl amino acids 2a–h, including their anti-inflammatory and cytotoxic effects and nitric oxide, TNF-α, and IL-1β production, is described.]

Synthesis of Biologically Potent Novel 5-(2-bromopyridin-3-yl-amino)-2- alkyl/aryl-isoindoline-1,3-dione Analogs Via Buchwald-Hartwig C-N Coupling Reaction

A novel series of N-alkyl/aryl substituted phthalimide analogs containing 2-bromopyridyl functionality were synthesized applying optimized Buchwald-Hartwig amination conditions using palladium acetate, cesium carbonate, and ±BINAP in toluene at 110°C under argon atmosphere. The target heteroaryl phthalimide derivatives were obtained in moderate yield ranging from 40% to 51%. In the extra precision (XP) docking studies, at the ATP site of human topoisomerase IIα (hTopoIIα) (PDB id 1ZXM), we identified that compound 3(a) demonstrated remarkable H-bond interactions with catalytic MG2+, ASN 91, SER 148, SER 149, ALA 167 and compound 3(c) with ARG 162, ASN 163, GLY 164, LSY 168, ASN 95 indicating their significance as a plausible hTopoIIα inhibitors. In the in vitro evaluation of A549 cell line, compounds 3(a) and 3(c) were observed to have only moderate cytotoxicity (IC50 180μg/ml and 210μg/ml respectively). The developed process could be widely employed for the synthesis of novel heterocyclic compounds with one of the components as N-alkyl/aryl substituted phthalimide derivatives and has the potential to be developed as a major route for the identification of active drug candidates. Keywords: Buchwald-Hartwig (C-N) coupling, BINAP, palladium acetate, phthalimide, topoisomerase II, in silico, in vitro antiproliferation, 1ZXM

A new series of N2-substituted-5-(p-toluenesulfonylamino)phthalimide analogues as α-glucosidase inhibitors

Several members of a new family of non-sugar-type α-glycosidase inhibitors, bearing a 5-(p-toluenesulfonylamino)phthalimide moiety and various substituent at the N2 position, were synthesized and their activities were investigated. The newly synthesized compounds displayed different inhibition profile towards yeast α-glycosidase and rat intestinal α-glycosidase. Almost all the compounds had strong inhibitory activities against yeast α-glycosidase. Regarding rat intestinal α-glycosidase, only analogs with N2-aromatic substituents displayed varying degrees of inhibitory activities on rat intestinal maltase and lactase and nearly all compounds showed no inhibition against rat intestinal α-amylase. Structure–activity relationship studies indicated that 5-(p-toluenesulfonylamino)phthalimide moiety is a favorable scaffold to exert the α-glucosidase inhibitory activity and substituents at the N2 position have considerable influence on the efficacy of the inhibition activities.

4,5,6,7-Tetrachloro-2-(1H-imidazol-2-yl)isoindoline-1,3-dione

4,5,6,7-Tetrachloro-2-(1H-imidazol-2-yl)isoindoline-1,3-dione was obtained by reaction of 2-aminoimidazole with 3,4,5,6-tetrachlorophthalic anhydride in refluxing acetic acid.

Inhibition of monoamine oxidase by C5-substituted phthalimide analogues

Literature reports that isatin as well as C5- and C6-substituted isatin analogues are reversible inhibitors of human monoamine oxidase (MAO) A and B. In general, C5- and C6-substitution of isatin leads to enhanced binding affinity to both MAO isozymes compared to isatin and in most instances result in selective binding to the MAO-B isoform. Crystallographic and modeling studies suggest that the isatin ring binds to the substrate cavities of MAO-A and -B and is stabilized by hydrogen bond interactions between the NH and the C2 carbonyl oxygen of the dioxoindolyl moiety and water molecules present in the substrate cavities of MAO-A and -B. Based on these observations and the close structural resemblances between isatin and its phthalimide isomer, a series of phthalimide analogues were synthesized and evaluated as MAO inhibitors. While phthalimide and N-aryl-substituted phthalimides were found to be weak MAO inhibitors, phthalimide homologues containing C5 substituents were potent reversible inhibitors of recombinant human MAO-B with IC50 values ranging from 0.007 to 2.5μM and moderately potent reversible inhibitors of recombinant human MAO-A with IC50 values ranging from 0.22 to 9.0μM. By employing molecular docking the importance of hydrogen bonding between the active sites of MAO-A and -B and the phthalimide inhibitors are highlighted.

A quantitative structure–activity relationship study on HIV-1 integrase inhibitors using genetic algorithm, artificial neural networks and different statistical methods

In this work, quantitative structure–activity relationship (QSAR) study has been done on tricyclic phthalimide analogues acting as HIV-1 integrase inhibitors. Forty compounds were used in this study. Genetic algorithm (GA), artificial neural network (ANN) and multiple linear regressions (MLR) were utilized to construct the non-linear and linear QSAR models. It revealed that the GA–ANN model was much better than other models. For this purpose, ab initio geometry optimization performed at B3LYP level with a known basis set 6–31G (d). Hyperchem, ChemOffice and Gaussian 98W softwares were used for geometry optimization of the molecules and calculation of the quantum chemical descriptors. To include some of the correlation energy, the calculation was done with the density functional theory (DFT) with the same basis set and Becke’s three parameter hybrid functional using the LYP correlation functional (B3LYP/6–31G (d)). For the calculations in solution phase, the polarized continuum model (PCM) was used and also included optimizations at gas-phase B3LYP/6–31G (d) level for comparison. In the aqueous phase, the root–mean–square errors of the training set and the test set for GA–ANN model using jack–knife method, were 0.1409, 0.1804, respectively. In the gas phase, the root–mean–square errors of the training set and the test set for GA–ANN model were 0.1408, 0.3103, respectively. Also, the R2 values in the aqueous and the gas phase were obtained as 0.91, 0.82, respectively.

Recent Advances in the Chemistry of Phthalimide Analogues and their Therapeutic Potential

Phthalimide analogues have been extensively used in medicinal chemistry owing to their wide range of applications as anti-convulsant, anti-inflammatory, analgesic, hypolipidimic and immunomodulatory activities. Number of anti-inflammatory phthalimide analogues have been synthesized as tumor necrosis factor-alpha (TNF-alpha) inhibitors. TNF-alpha plays a critical role in certain physiological immune systems and its over-production causes severe damage to the host. It promotes the inflammatory response leading to many of the clinical problems associated with auto-immune disorders like rheumatoid arthritis, Crohn's disease, ankylosing spondylitis, psoriasis and refractory asthma. One of the phthalimide derivatives, LASSBio-468, was recently demonstrated to inhibit TNF-alpha production induced by lipopolysaccharide (LPS), in vivo. Its potential against chronic inflammatory diseases was also witnessed. Another derivative, DIMP, showed good anti-androgenic activity. These analogues have also been employed for the synthesis of several kinds of important therapeutic synthones. However extensive research on the chemistry and biological activities of phthalimide analogues have been carried out and number of reports appeared, a compilation focusing on chemistry and biological activity is still needed. This review, concisely describes the chemical and therapeutic aspects of phthalimide derivatives.

Separation of α-glucosidase-inhibitory and liver X receptor-antagonistic activities of phenethylphenyl phthalimide analogs and generation of LXRα-selective antagonists

Liver X receptor (LXR) α/β dual agonists are candidate medicaments for the treatment of metabolic syndrome, because their biological actions include increasing cholesterol efflux mediated by LXRβ. However, their clinical application is currently limited by their enhancing effect on triglyceride (TG) synthesis mediated by LXRα. Combination of an LXRα-selective antagonist with an LXRα/β dual agonist may overcome this disadvantage. In the present work, structural development studies of phenethylphenyl phthalimide 9, which possesses LXRα/β dual-antagonistic activity and α-glucosidase-inhibitory activity, led to the LXRα-selective antagonist 23f. Specific α-glucosidase inhibitors were also obtained.

QSAR analysis of some phthalimide analogues based inhibitors of HIV-1 integrase

A quantitative structure activity relationship (QSAR) study has been performed on phthalimide analogues based inhibitors of HIV-1 integrase to understand the structural features influencing the affinity of these inhibitors towards the enzyme. The compounds in the selected series were characterized by molecular descriptors calculated using the QSAR software Dragon and molecular modeling software ChemOffice 2001. QSAR models were derived by stepwise multiple regression analysis employing the method of least squares. The best QSAR model describing the HIV-1 integrase inhibitory activity of phthalimide analogues was selected on the basis of statistical significance and predictive ability as gauged by cross-validation procedure and external test-set method. The generated QSAR models revealed that increased HIV-1 inhibitory potency of tricyclic phthalimide derivatives could be achieved by increasing the overall lipophilicity of the molecules and by incorporating halogen substituents in the benzylic aromatic ring attached to the phthalimido nitrogen atom. Additionally, the model also suggests that the increase in the molecular flexibility by incorporation of rotatable bonds is conducive for HIV-1 inhibitory activity of phthalimide derivatives whereas increase in molecular branching appears to be detrimental to the activity.

Design and Optimization of Tricyclic Phtalimide Analogues as Novel Inhibitors of HIV-1 Integrase

Human immunodeficiency virus type-1 integrase is an essential enzyme for effective viral replication and hence a valid target for the design of inhibitors. We report here on the design and synthesis of a novel series of phthalimide analogues as integrase inhibitors. The short synthetic pathway enabled us to synthesize a series of analogues with a defined structure diversity. The presence of a single carbonyl-hydroxy-aromatic nitrogen motif was shown to be essential for the enzymatic activity and this was confirmed by molecular docking studies. The enzymatically most active compound from this series is 7-(3,4-dichlorobenzyl)-5,9-dihydroxypyrrolo[3,4-g]quinoxaline-6,8-dione (15l) with an IC(50) value of 112 nM on the HIV-1 integrase enzyme, while ((7-(4-chlorobenzyl)-5,9-dihydroxy-pyrrolo[3,4-g]quinoxaline-6,8-dione (15k)) showed an EC(50) of 270 nM against HIV-1 in a cell-based assay.

ChemInform Abstract: Synthesis and Antitumor Activity of Some New Phthalimide Analogues.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Phthalimide analogs of CB 1954: synthesis and bioactivation.

Four novel 4-substituted 5-nitrophthalimides (5-substituted-6-nitro-1,3-dihydro-isoindol-1,3-diones), 6, 7, 10 and 11, and the known 5 are prepared as analogs of the dinitrobenzamide prodrug CB 1954, 1, and considered as potential candidates for gene-directed enzyme prodrug therapy. All the phthalimides are poor substrates for Escherichia coli nitroreductase compared to CB 1954. However, 6, 7, 10 and 11 are reduced by both the human and rat forms of DT-diaphorase; 10 is a particularly good substrate but 7 decomposes in phosphate buffer. A cell-line panel consisting of V79 cells that have been engineered to express various levels of either the human or rat forms of DT-diaphorase in an identical cellular background was used to evaluate these compounds as prodrugs activated by this enzyme. The cytotoxic effect of CB 1954 is proportional to the activity of either the rat or human enzyme but cells expressing the rat enzyme were much more sensitive (10000-fold at higher levels of DT-diaphorase activity) than cells expressing comparable levels of the human enzyme. These results demonstrate that the resistance of human tumors to CB 1954 can be accounted for solely by the kinetic properties of the enzyme for this prodrug. The nitrophthalimide analogs overcome this kinetic failing of CB 1954. However, these compounds are not activated to produce cytotoxicity in these DT-diaphorase-expressing cell lines. It is postulated their reduction products fail to undergo an acylation reaction in a manner analogous to CB 1954. Thus, reduction by DT-diaphorase is not predictive of cytotoxicity in this class of prodrugs.

Interaction of thalidomide, phthalimide analogues of thalidomide and pentoxifylline with the anti-tumour agent 5,6-dimethylxanthenone-4-acetic acid: concomitant reduction of serum tumour necrosis factor-alpha and enhancement of anti-tumour activity.

DMXAA (5,6-dimethylxanthenone-4-acetic acid), a novel anti-tumour agent currently undergoing clinical evaluation, appears to mediate its anti-tumour effects through immune modulation and the production of the cytokine tumour necrosis factor-alpha (TNF). Our previous studies have shown that thalidomide, a potent inhibitor of TNF biosynthesis that has numerous biological effects, including inhibition of tumour angiogenesis, unexpectedly augments the anti-tumour response in mice to DMXAA. We show here that thalidomide (100 mg kg(-1)) has no effect when administered with inactive doses of DMXAA, and that it must be given simultaneously with an active dose of DMXAA to have its maximum potentiating effect on the growth of the murine Colon 38 adenocarcinoma. To address the issue of whether inhibition of serum TNF production is important for potentiation of anti-tumour activity, we have tested three potent analogues of thalidomide. All three analogues, when co-administered with DMXAA to mice at doses lower than those used with thalidomide, inhibited TNF production and were effective in potentiating the anti-tumour activity of DMXAA against transplanted Colon 38 tumours. One of the analogues, N-phenethyltetrafluorophthalimide, was 1000-fold more potent than thalidomide and at a dose of 0.1 mg kg(-1) in combination with DMXAA (30 mg kg(-1)) cured 100% of mice, compared with 67% for the group treated with DMXAA alone. We also tested pentoxifylline and found it to suppress TNF production in response to DMXAA and to potentiate the anti-tumour effect of DMXAA. The results are compatible with the hypothesis that pharmacological reduction of serum TNF levels might benefit the anti-tumour effects of DMXAA and suggest new strategies for therapy using this agent.

Novel Biological Response Modifiers Derived from Thalidomide

Thalidomide (N-alpha-phthalimidoglutarimide) was used widely as a hypnotic/sedative agent in the late 1950s and the early 1960s, but had to be withdrawn from the market because of its severe teratogenicity. In spite of this, there has been a resurgence of interest in the drug in recent years due to its potential usefulness for the treatment of various diseases, including acquired immunodeficiency syndrome (AIDS) and graft-versus-host disease (GVHD). The effectiveness of the drug in these diseases has been attributed to its specific inhibitory activity on tumor necrosis factor-alpha (TNF-alpha) production. Because TNF-alpha, a cytokine mediating host defence and immune regulation, with a wide range of activities, has deleterious pathophysiological effects in various diseases, including AIDS, tumors, rheumatoid arthritis and diabetes, its production-regulators are attractive lead compounds for novel biological response modifiers. The regulatory effect of thalidomide on TNF-alpha production has been found to be bidirectional, depending on both the cell-type and the TNF-alpha production-inducer; i.e., thalidomide possesses both enhancing and inhibiting activities on TNF-alpha production. Structural modification of thalidomide aiming at the creation of superior TNF-alpha production-regulators has afforded a number of phenyl- and benzylphthalimide analogs possessing more potent activity than thalidomide itself. The structure-activity relationships of these analogs has been investigated. The bidirectional TNF-alpha production-regulating activity is electronic state- and enantio-dependent, and both pure inhibitors and pure enhancers of TNF-alpha production has been obtained. Further structural development of the phthalimide analogs has yielded potent non-steroidal androgen antagonists.

Tumor necrosis factor-alpha production-inhibiting activity of phthalimide analogues on human leukemia THP-1 cells and a structure-activity relationship study

N-Substituted phthalimides (2-substituted 1 H-isoindole-1,3-diones) were prepared and their inhibitory effects on tumor necrosis factor-alpha (TNF-α) production by human leukemia cell line THP-1 stimulated with 12- O-tetradecanoylphorbol 13-acetate (TPA) or okadaic acid (OA) were examined. A structure-activity relationship study of these phthalimide analogues revealed that their inhibitory effects on TPA- and OA-induced TNF-α production by THP-1 cells are well correlated to each other, i.e. they may involve the same target molecule(s). An analysis by the use of phthalimide analogue-immobilized affinity gels indicated the existence of several phthalimide-binding proteins in THP-1 cell extract.

Potent novel nonsteroidal androgen antagonists with a phthalimide skeleton

Anti-androgenic activity of various phthalimide analogs was evaluated based on inhibition of androgen-induced activation of nuclear androgen receptor (CAT assay) and on growth inhibition of the androgen-dependent clonal cell line SC-3. Some compounds showed very potent androgen-antagonistic activity.

Novel biological response modifiers: phthalimides with TNF-alpha production regulating activity

Tumor necrosis factor alpha (TNF-alpha), an important cytokine produced mainly by activated macrophages, plays a critical role in certain physiological immune systems. But it causes severe damage to the host when produced in excess. Therefore, TNF-alpha can be regarded to possess both favorable and unfavorable effects. These pleiotropic effects indicated that TNF-alpha production-enhancers in some cases and TNF-alpha production-inhibitors in other cases would be useful as biological response modifiers (BRMs) under various circumstances. A possible lead compound is thalidomide, which had been used as a hypnotic/sedative agents but was withdrawn from the market because of it's teratogenicity. Thalidomide is a specific inhibitor of TNF-alpha production, and this effect has been shown to be useful for the treatment of various immunodiseases. Recently, we found that the regulation of TNF-alpha production by thalidomide and related hthalimides was both inducer-specific and cell-type-specific, i.e., (I) the compounds enhance 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced TNF-alpha production by HL-60 cells, while they inhibit TPA-induced TNF-alpha production by another human leukemia cell line THP-1, and (II) the compounds inhibit TNF-alpha production both by HL-60 and THP-1 cells when the cells are stimulated with okadaic acid. We also found that in a optically active phthalimide analogues of thalidomide the inducer specific bi-directional regulation of TNF-alpha production is separated. This implies that the target molecule(s) of the two systems are different each other.

Enantio-dependence of inducer-specific bidirectional regulation of tumor necrosis factor (TNF)-alpha production: Potent TNF-α production inhibitors

In optically active phthalimide analogs of thalidomide, the inducer-specific TNF-α production-enhancing and -inhibiting activities are separated. This implies that the target molecules of the two activities are different.

Phthalimide analogs with TNF-α production-enhancing activity

Phthalimide analogs with TNF-α production-enhancing activity

Inducer-Specific Bidirectional Regulation by Thalidomide and Phenylphthalimides of Tumor Necrosis Factor-α Production

Regulation by thalidomide [N(α)-phthalimidoglutarimide] of tumor necrosis factor (TNF)-α production was found to be inducer-specific. Thalidomide enhances TNF-α production by human leukemia HL-60 cells induced with 12-O-tetradecanoylphorbol 13-acetate (TPA), while it inhibits TNF-α production induced with okadaic acid (OA) in the same cell line. Some phthalimide analogs, including PP-33 [2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione] and its 4,5,6,7-tetrafluoro derivative (FPP-33), also showed such an inducer-specific bidirectional TNF-α production-regulating activity. The structure–activity relationships of the compounds tested are similar, but not identical, in the TPA-stimulated HL-60 and OA-stimulated HL-60 assay systems.