Succinimide Derivatives as Acetylcholinesterase Inhibitors-In Silico and In Vitro Studies.

We studied the effect of succinimide derivatives on acetylcholinesterase activity due to the interest in compounds that influence this enzyme's activity, which could help treat memory issues more effectively. The following parameters were established for this purpose based on kinetic investigations of the enzyme in the presence of succinimide derivatives: the half-maximal inhibitory concentration, the maximum rate, the inhibition constant, and the Michaelis-Menten constant. Furthermore, computational analyses were performed to determine the energy required for succinimide derivatives to dock with the enzyme's active site. The outcomes acquired in this manner demonstrated that all compounds inhibited acetylcholinesterase in a competitive manner. The values of the docking energy parameters corroborated the kinetic parameter values, which indicated discernible, albeit slight, variations in the inhibitory intensity among the various derivatives.

Ru(II)-Catalyzed C-H Alkylation of N-Benzyltriflamide with Maleimides: Synthesis of o-Succinimide Substituted Benzaldehydes.

A ruthenium-catalyzed N-benzyltriflamide assisted C-H alkylation with maleimide followed by hydrolysis of in situ generated imine has been developed for the first time. This synthetic method results in the efficient synthesis of o-succinimide derivatives of benzaldehydes. This reaction involves less expensive and mild reaction conditions and shows excellent site selectivity and good functional group compatibility.

Wide Bandgap Polymer Donors Based on Succinimide-Substituted Thiophene for Nonfullerene Organic Solar Cells.

The advent of nonfullerene acceptors (NFAs) has greatly improved the photovoltaic performance of organic solar cells (OSCs). However, to compete with other solar cell technologies, there is a pressing need for accelerated research and development of improved NFAs as well as their compatible wide bandgap polymer donors. In this study, a novel electron-withdrawing building block, succinimide-substituted thiophene (TS), is utilized for the first time to synthesize three wide bandgap polymer donors: PBDT-TS-C5, PBDT-TSBT-C12, and PBDTF-TSBT-C16. These polymers exhibit complementary bandgaps for efficient sunlight harvesting and suitable frontier energy levels for exciton dissociation when paired with the extensively studied NFA, Y6. Among these donors, PBDTF-TSBT-C16 demonstrates the highest hole mobility and a relatively low highest occupied molecular orbital (HOMO) energy level, attributed to the incorporation of thiophene spacers and electron-withdrawing fluorine substituents. OSC devices based on the blend of PBDTF-TSBT-C16:Y6 achieve the highest power conversion efficiency of 13.21%, with a short circuit current density (Jsc) of 26.83 mA cm-2, an open circuit voltage (Voc) of 0.80 V, and a fill factor of 0.62. Notably, the Voc × Jsc product reaches 21.46 mW cm-2, demonstrating the potential of TS as an electron acceptor building block for the development of high-performance wide bandgap polymer donors in OSCs.

Discovery and Control of Succinimide Formation and Accumulation at Aspartic Acid Residues in The Complementarity-Determining Region of a Therapeutic Monoclonal Antibody.

PURPOSE: Succinimide formation and isomerization alter the chemical and physical properties of aspartic acid residues in a protein. Modification of aspartic acid residues within complementarity-determining regions (CDRs) of therapeutic monoclonal antibodies (mAbs) can be particularly detrimental to the efficacy of the molecule. The goal of this study was to characterize the site of succinimide accumulation in the CDR of a therapeutic mAb and understand its effects on potency. Furthermore, we aimed to mitigate succinimide accumulation through changes in formulation. METHODS: Accumulation of succinimide was identified through intact and reduced LC-MS mass measurements. A low pH peptide mapping method was used for relative quantitation and localization of succinimide formation in the CDR. Statistical modeling was used to correlate levels of succinimide with basic variants and potency measurements. RESULTS: Succinimide accumulation in Formulation A was accelerated when stored at elevated temperatures. A strong correlation between succinimide accumulation in the CDR, an increase in basic charge variants, and a decrease in potency was observed. Statistical modeling suggest that a combination of ion exchange chromatography and potency measurements can be used to predict succinimide levels in a given sample. Reformulation of the mAb to Formulation B mitigates succinimide accumulation even after extended storage at elevated temperatures. CONCLUSION: Succinimide formation in the CDR of a therapeutic mAb can have a strong negative impact on potency of the molecule. We demonstrate that thorough characterization of the molecule by LC-MS, ion exchange chromatography, and potency measurements can facilitate changes in formulation that mitigate succinimide formation and the corresponding detrimental changes in potency.

A diastereoselective three-component reaction for the assembly of succinimide and isatin hybrid molecules with potent anticancer activities.

A Rh2(OAc)4 catalyzed three-component reaction of vinyl diazosuccinimides with alcohols and isatins has been reported, which provides a practical assess to the direct assembly of succinimide and isatin hybrid molecules in good-to-high yields with excellent stereoselectivity. The antiproliferation activity of these synthesized succinimide and isatin hybrid products has been tested via the CCK8 assay in different cancer cell lines, and compounds 4g (SJSA-1, IC50 = 3.82 µM) and 4r (HCT-116, IC50 = 9.02 µM) exhibit higher anticancer potency than other tested compounds.

New Derivatives of N-Hydroxybutanamide: Preparation, MMP Inhibition, Cytotoxicity, and Antitumor Activity.

Using a novel method of N-substituted succinimide ring opening, new N-hydroxybutanamide derivatives were synthesized. These compounds were evaluated for their ability to inhibit matrix metalloproteinases (MMPs) and their cytotoxicity. The iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide showed the inhibition of MMP-2, MMP-9, and MMP-14 with an IC50 of 1-1.5 µM. All the compounds exhibited low toxicity towards carcinoma cell lines HeLa and HepG2. The iodoaniline derivative was also slightly toxic to glioma cell lines A-172 and U-251 MG. Non-cancerous FetMSC and Vero cells were found to be the least sensitive to all the compounds. In vivo studies demonstrated that the iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide had low acute toxicity. In a mouse model of B16 melanoma, this compound showed both antitumor and antimetastatic effects, with a 61.5% inhibition of tumor growth and an 88.6% inhibition of metastasis. Our findings suggest that the iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide has potential as a lead structure for the development of new MMP inhibitors. Our new synthetic approach can be a cost-effective method for the synthesis of inhibitors of metalloenzymes with promising antitumor potential.

Exploration of Succinimide Derivative as a Multi-Target, Anti-Diabetic Agent: In Vitro and In Vivo Approaches.

Diabetes mellitus (DM) is counted among one of the leading challenges in the recent era, and it is a life-threatening disorder. Compound 4-hydroxy 3-methoxy phenylacetone (compound 1) was previously isolated from Polygonum aviculare. This compound was reacted with N-benzylmaleimide to synthesize the targeted compound 3. The purpose of this research is to exhibit our developed compound 3's ability to concurrently inhibit many targets that are responsible for hyperglycemia. Compound 3 was capable of inhibiting α-amylase, α-glucosidase, and protein tyrosine phosphatase 1 B. Even so, outstanding in vitro inhibition was shown by the compound against dipeptidyl peptidase-4 (DPP-4) with an IC50 value of 0.07 µM. Additionally, by using DPPH in the antioxidant activity, it exhibited good antioxidant potential. Similarly, in the in vivo activity, the experimental mice proved to be safe by treatment with compound 3. After 21 days of examination, the compound 3 activity pattern was found to be effective in experimental mice. Compound 3 decreased the excess peak of total triglycerides, total cholesterol, AST, ALT, ALP, LDL, BUN, and creatinine in the STZ-induced diabetic mice. Likewise, the histopathology of the kidneys, liver, and pancreas of the treated animals was also evaluated. Overall, the succinimde moiety, such as compound 3, can affect several targets simultaneously, and, finally, we were successful in synthesizing a multi-targeted preclinical therapy.

Chiral Phosphine Catalyzed Allylic Alkylation of Benzylidene Succinimides with Morita-Baylis-Hillman Carbonates.

Owing to their unique chemical properties, α-alkylidene succinimides generally act as versatile synthons in organic synthesis. Compared with well-established annulations, nucleophilic alkylations of α-alkylidene succinimides are very limited. Accordingly, an organocatalytic allylic alkylation of α-benzylidene succinimides with Morita-Baylis-Hillman (MBH) carbonates was established. In the presence of a chiral phosphine catalyst, α-benzylidene succinimides reacted smoothly with MBH carbonates under mild conditions to furnish a series of optical active succinimides in high yields and enantioselectivities. Different from the reported results, the organocatalytic enantioselective construction of pyrrolidine-2,5-dione frameworks bearing contiguous chiral tertiary carbon centers was achieved via this synthetic strategy. Scaling up the reaction indicated that it is a practical strategy for the organocatalytic enantioselective alkylation of α-alkylidene succinimides. A possible reaction mechanism was also proposed.

New Succinimide-Thiazolidinedione Hybrids as Multitarget Antidiabetic Agents: Design, Synthesis, Bioevaluation, and Molecular Modelling Studies.

Diabetes mellitus (DM) is a metabolic disorder majorly arising from the pathophysiology of the pancreas manifested as a decline in the insulin production or the tissue's resistance to the insulin. In this research, we have rationally designed and synthesized new succinimide-thiazolidinedione hybrids for the management of DM. In a multistep reaction, we were able to synthesize five new derivatives (10a-e). All the compounds were new containing a different substitution pattern on the N-atom of the succinimide ring. Initially, all the compounds were tested against the in vitro α-glucosidase, α-amylase, PTP1B, and DPP4 targets. In all of these targets, the compound 10d was observed to be the most potential antidiabetic agent. Based on this, the antidiabetic activity of the compound 10d was further investigated in experimental animals, which overall gave us encouraging results. The molecular docking studies of the compound 10d was also performed against the target enzymes α-glucosidase, α-amylase, PTP1B, and DPP4 using MOE. Overall, we observed that we have explored a new class of compounds as potential antidiabetic agents.

Synthesis, Molecular Docking, and Preclinical Evaluation of a New Succinimide Derivative for Cardioprotective, Hepatoprotective and Lipid-Lowering Effects.

Cardiac and hepatotoxicities are major concerns in the development of new drugs. Better alternatives to other treatments are being sought to protect these vital organs from the toxicities of these pharmaceuticals. In this regard, a preclinical study is designed to investigate the histopathological effects of a new succinimide derivative (Comp-1) on myocardial and liver tissues, and the biochemical effects on selected cardiac biomarkers, hepatic enzymes, and lipid profiles. For this, an initially lethal/toxic dose was determined, followed by a grouping of selected albino rats into five groups (each group had n = 6). The control group received daily oral saline for 8 days. The 5-FU (5-Fluorouracil) group received oral saline daily for 8 days, added with the administration of a single dose of 5-FU (150 mg/kg I.P.) on day 5 of the study. The atenolol group received oral atenolol (20 mg/kg) for 8 days and 5-FU (150 mg/kg I.P.) on day 5 of the protocol. Similarly, two groups of rats treated with test compound (Comp-1) were administered with 5 mg/kg I.P. and 10 mg/kg I.P. for 8 days, followed by 5-FU (150 mg/kg I.P.) on day 5. Toxicity induced by 5-FU was manifested by increases in the serum creatinine kinase myocardial band (CK-MB), troponin I (cTnI) and lactate dehydrogenase (LDH), lipid profile, and selected liver enzymes, including ALP (alkaline phosphatase), ALT (alanine transaminase), AST (aspartate aminotransferase), BT (bilirubin total), and BD (direct bilirubin). These biomarkers were highly significantly decreased after the administration of the mentioned doses of the test compound (5 mg/kg and 10 mg/kg). Similarly, histological examination revealed cardiac and hepatic tissue toxicity by 5-FU. However, those toxic effects were also significantly recovered/improved after the administration of Comp-1 at the said doses. This derivative showed dose-dependent effects and was most effective at a dose of 10 mg/kg body weight. Binding energy data computed via docking simulations revealed that our compound interacts toward the human beta2-adrenergic G protein-coupled receptor (S = -7.89 kcal/mol) with a slight stronger affinity than the calcium channel T-type (S = -7.07 kcal/mol). In conclusion, the histological and biochemical results showed that the test compound (Comp-1) had prominent cardioprotective, hepatoprotective, and lipolytic effects against 5-FU-induced toxicity in the subjected animal model.

Antioxidant Activity of Ruthenium Cyclopentadienyl Complexes Bearing Succinimidato and Phthalimidato Ligands.

In these studies, we investigated the antioxidant activity of three ruthenium cyclopentadienyl complexes bearing different imidato ligands: (η5-cyclopentadienyl)Ru(CO)2-N-methoxysuccinimidato (1), (η5-cyclopentadienyl)Ru(CO)2-N-ethoxysuccinimidato (2), and (η5-cyclopentadienyl)Ru(CO)2-N-phthalimidato (3). We studied the effects of ruthenium complexes 1-3 at a low concentration of 50 µM on the viability and the cell cycle of peripheral blood mononuclear cells (PBMCs) and HL-60 leukemic cells exposed to oxidative stress induced by hydrogen peroxide (H2O2). Moreover, we examined the influence of these complexes on DNA oxidative damage, the level of reactive oxygen species (ROS), and superoxide dismutase (SOD) activity. We have observed that ruthenium complexes 1-3 increase the viability of both normal and cancer cells decreased by H2O2 and also alter the HL-60 cell cycle arrested by H2O2 in the sub-G1 phase. In addition, we have shown that ruthenium complexes reduce the levels of ROS and oxidative DNA damage in both cell types. They also restore SOD activity reduced by H2O2. Our results indicate that ruthenium complexes 1-3 bearing succinimidato and phthalimidato ligands have antioxidant activity without cytotoxic effect at low concentrations. For this reason, the ruthenium complexes studied by us should be considered interesting molecules with clinical potential that require further detailed research.

New insights into the mechanisms of age-related protein-protein crosslinking in the human lens.

Although protein crosslinking is often linked with aging as well as some age-related diseases, very few molecular details are available on the nature of the amino acids involved, or mechanisms that are responsible for crosslinking. Recent research has shown that several amino acids are able to generate reactive intermediates that ultimately lead to covalent crosslinking through multiple non-enzymatic mechanisms. This information has been derived from proteomic investigations on aged human lenses and the mechanisms of crosslinking, in each case, have been elucidated using model peptides. Residues involved in spontaneous protein-protein crosslinking include aspartic acid, asparagine, cysteine, lysine, phosphoserine, phosphothreonine, glutamic acid and glutamine. It has become clear, therefore, that several amino acids can act as potential sites for crosslinking in the long-lived proteins that are present in aged individuals. Moreover, the lens has been an invaluable model tissue and source of crosslinked proteins from which to determine crosslinking mechanisms that may lead to crosslinking in other human tissues.

Understanding the pathway and kinetics of aspartic acid isomerization in peptide mapping methods for monoclonal antibodies.

Isomerization of aspartic acid (Asp) in therapeutic proteins could lead to safety and efficacy concerns. Thus, accurate quantitation of various Asp isomerization along with kinetic understanding of the variant formations is needed to ensure optimal process development and sufficient product quality control. In this study, we first observed Asp-succinimide conversion in complementarity-determining regions (CDRs) Asp-Gly motif of a recombinant mAb through ion exchange chromatography, intact protein analysis by mass spectrometry, and LC-MS/MS. Then, we developed a specific peptide mapping method, with optimized sample digestion conditions, to accurately quantitate Asp-succinimide-isoAsp variants at peptide level without method-induced isomerization. Various kinetics of Asp-succinimide-isoAsp isomerization pathways were elucidated using 18O labeling followed by LC-MS analysis. Molecular modeling and molecular dynamic simulation provide additional insight on the kinetics of Asp-succinimide formation and stability of succinimide intermediate. Findings of this work shed light on the molecular construct and the kinetics of the formation of isoAsp and succinimide in peptides and proteins, which facilitates analytical method development, protein engineering, and late phase development for commercialization of therapeutic proteins.

Newly Found Digital Memory Characteristics of Pyrrolidone- and Succinimide-Based Polymers.

This study reports for the first time the excellent nonvolatile and volatile digital memory characteristics of polymers bearing 2-pyrrolidone and succinimide moieties. A series of new polymers is synthesized from poly(ethylene-alt-maleic anhydride) and four alcohol derivatives with and without 2-pyrrolidone and succinimide moieties. All polymers, including polyvinylpyrrolidone, are found to be thermally stable up to 195 °C or higher, and characterized regarding their molecular orbital energy levels, bandgap, and resistive digital memory behaviors. Excitingly, the polymers bearing either 2-pyrrolidone or succinimide moiety demonstrate p-type digital memory behaviors with high ON/OFF current ratios and long reliabilities. Nonvolatile digital memory performance is achieved over the film thickness range of 10-80 nm, whereas volatile digital memory is demonstrated over a much narrower range of film thickness. All digital memory performances can be originated from the 2-pyrrolidone and succinimide moieties possessing high affinity and stabilization power to charges via charge traps and transformations based on a hopping conduction process. Hence, these new polymers are suitable for the production of high-performance p-type nonvolatile and volatile digital memory devices. Moreover, 2-pyrrolidone and succinimide can be used as new and economical electroactive building blocks for the development of advanced digital memory materials.

Research progress in biological activities of succinimide derivatives.

Succinimides are well recognized heterocyclic compounds in drug discovery which produce diverse therapeutically related applications in pharmacological practices. Researches in medicinal chemistry field have isolated and synthesized succinimide derivatives with multiple medicinal properties including anticonvulsant, anti-inflammatory, antitumor and antimicrobial agents, 5-HT receptor ligands and enzyme inhibitors. Simultaneously, SAR (Structure-Activity Relationship) analysis has been gradually possessed, along with a great deal of derivatives have been derived for potential targets. In this article, we comprehensively summarize the biological activities and SAR for succinimide derivatives, along with the featuring bioactive molecules reported in patents, wishing to provide an overall retrospect and prospect on the succinimide analogues.

Three-Component Access to Functionalized Spiropyrrolidine Heterocyclic Scaffolds and Their Cholinesterase Inhibitory Activity.

A novel one-pot [3+2]-cycloaddition reaction of (E)-3-arylidene-1-phenyl-succinimides, cyclic 1,2-diketones (isatin, 5-chloro-isatin and acenaphtenequinone), and diverse α-aminoacids such as 2-phenylglycine or sarcosine is reported. The reaction provides succinimide-substituted dispiropyrrolidine derivatives with high regio- and diastereoselectivities under mild reaction conditions. The stereochemistry of these N-heterocycles has been confirmed by four X-ray diffraction studies. Several synthetized compounds show higher inhibition on acetylcholinesterase (AChE) than butyrylcholinesterase (BChE). Of the 17 synthesized compounds tested, five exhibit good AChE inhibition with IC50 of 11.42 to 22.21 µM. A molecular docking study has also been undertaken for compound 4n possessing the most potent AChE inhibitory activity, disclosing its binding to the peripheral anionic site of AChE enzymes.

Characterization and quantification of succinimide using peptide mapping under low-pH conditions and hydrophobic interaction chromatography.

Characterization of asparagine deamidation and aspartic acid isomerization is an important aspect of biotherapeutic protein analysis due to the potential negative effect of these modifications on drug efficacy and stability. Succinimide has long been known to be an intermediate product of asparagine deamidation and aspartic acid isomerization, but despite the key role of succinimide in these reactions, its analysis remains challenging due to its instability. We have developed a paradigm in which two interlinked analytical methods are used to develop an optimized approach to analyze succinimide. In the first method, low-pH protein digestion is used for detailed characterization of succinimide with peptide mapping. At low pH, succinimide is stable and can be analyzed with accurate mass measurements and tandem mass spectrometry to confirm its identity and localize its modification site. These results are then used to establish a hydrophobic interaction chromatography (HIC)-based method that can be used for release and stability studies. In this method, unmodified protein, deamidated products, and succinimide are well separated and quantified. Good correlation was obtained between the data from low-pH protein digestion-based peptide mapping and the HIC-based method. Method qualification showed that the HIC-based method is robust, accurate, and precise and has excellent linearity.

Synthesis, in-vitro α-glucosidase inhibition, antioxidant, in-vivo antidiabetic and molecular docking studies of pyrrolidine-2,5-dione and thiazolidine-2,4-dione derivatives.

α-Glucosidase is considered as a therapeutic target for the treatment of type 2 diabetes mellitus (DM2). In current study, we synthesized pyrrolidine-2,5-dione (succinimide) and thiazolidine-2,4-dione derivatives and evaluated for their ability to inhibit α-Glucosidase. Pyrrolidine-2,5-dione derivatives (11a-o) showed moderate to poor α-glucosidase inhibition. Compound 11o with the IC50 value of 28.3 ±â€¯0.28 µM emerged as a good inhibitor of α-glucosidase. Thiazolidine-2,4-dione and dihydropyrimidine (TZD-DHPM) hybrids (22a-c) showed excellent inhibitory activities. The most active compound 22a displayed IC50 value of 0.98 ±â€¯0.008 µM. Other two compounds of this series also showed activity in low micromolar range. The in-vivo antidiabetic study of three compounds 11n, 11o and 22a were also determined using alloxan induced diabetes mice model. Compounds 11o and 22a showed significant hypoglycemic effect compared to the reference drug. In-vivo acute toxicity study showed the safety of these selected compounds. In-silico docking studies were carried out to rationalize the in-vitro results. The binding modes and bioassay results of TZD-DHPM hybrids showed that interactions with important residues appeared significant for high potency.

Comparison of the activation energy barrier for succinimide formation from α- and ß-aspartic acid residues obtained from density functional theory calculations.

The l-α-Asp residues in peptides or proteins are prone to undergo nonenzymatic reactions to form l-ß-Asp, d-α-Asp, and d-ß-Asp residues via a succinimide five-membered ring intermediate. From these three types of isomerized aspartic acid residues, particularly d-ß-Asp has been widely detected in aging tissue. In this study, we computationally investigated the cyclization of α- and ß-Asp residues to form succinimide with dihydrogen phosphate ion as a catalyst (H2PO4-). We performed the study using B3LYP/6-31+G(d,p) density functional theory calculations. The comparison of the activation barriers of both residues is discussed. All the calculations were performed using model compounds in which an α/ß-Asp-Gly sequence is capped with acetyl and methylamino groups on the N- and C-termini, respectively. Moreover, H2PO4- catalyzes all the steps of the succinimide formation (cyclization-dehydration) acting as a proton-relay mediator. The calculated activation energy barriers for succinimide formation of α- and ß-Asp residues are 26.9 and 26.0kcalmol-1, respectively. Although it was experimentally confirmed that ß-Asp has higher stability than α-Asp, there was no clear difference between the activation barriers. Therefore, the higher stability of ß-Asp residue than α-Asp residue may be caused by an entropic effect associated with the succinimide formation.

Two New Succinimide Derivatives Cladosporitins A and B from the Mangrove-derived Fungus Cladosporium sp. HNWSW-1.

Two new succinimide-containing derivatives, cladosporitins A (1) and B (2), were isolated from the fermentation cultures of the mangrove-derived fungus Cladosporium sp. HNWSW-1, along with a new pyrone, clapone (3), as well as the previously reported talaroconvolutin A (4) and anthraquinone (5). The structures of the isolated compounds were elucidated by 1D, 2D NMR, and HRMS spectral analysis. Compound 2 showed cytotoxicity against BEL-7042, K562 and SGC-7901 cell lines with IC50 values of 29.4 ± 0.35 µM, 25.6 ± 0.47 µM, and 41.7 ± 0.71 µM, respectively, whereas compound 4 exhibited cytotoxicity against Hela and BEL-7042 cell lines with IC50 values of 14.9 ± 0.21 µM and 26.7 ± 1.1 µM, respectively. In addition, compounds 4 and 5 displayed inhibitory activity against α-glycosidase, with IC50 values of 78.2 ± 2.1 µM and 49.3 ± 10.6 µM, respectively.