Molecular Modeling,Synthesis, and Anti‐HIV Activity of Novel Isoindolinedione Analogues as Potent Non‐nucleoside Reverse Transcriptase Inhibitors

Different isoindolinedione derivatives bearing imine, amide, thioamide, and sulfonamide linkages have been designed in silico using discovery studio software (BIOVIA, San Diego, CA, USA), synthesized, and evaluated for their anti‐HIV activity. SAR studies revealed that the linkages in these molecules did affect their anti‐HIV activity and the molecules having sulfonamide linkages were the most potent HIV‐RT inhibitors as the S=O bonds of the sulfonamide moiety interacted with Lys103 (NH or carbonyl or both) and Pro236; the NH part of the sulfonamide linkage formed bond with carbonyl of Lys101. blood–brain barrier (BBB) plots were also studied, and it was found that all the designed molecules have potential to cross BBB, a very vital criteria for anti‐HIV drugs. In vitro screening was performed using HIV‐1 strain IIIB in MT‐4 cells using the MTT assay, and it was seen that some of these molecules were effective inhibitors of HIV‐1 replication at nanomolar concentration with selectivity indices ranging from 33.75 to 73.33 under in vitro conditions. Some of these molecules have shown good anti‐HIV activity at 3–4 nm concentrations. These derivatives have potential to be developed as lead molecules effective against HIV‐1. Novel isoindolinedione derivatives as probable NNRTIs have been synthesized and characterized. Some of these molecules have shown good anti‐HIV activity at 3–4 nm concentrations.     

Synthesis,Evaluation of Pharmacological Activities and Quantitative Structure–Activity Relationship Studies of a Novel Group of bis(4‐Nitroaryl‐1,4‐dihyropyridine)

Voltage‐dependent calcium channels are crucial targets for a wide range of clinically active pharmacological agents. From these agents, 1,4‐dihydropyridines constitute a group of small organic compounds are based on a core pyridine structure which can both block and enhance calcium currents. They are considered specific for L‐Type calcium channels; however, other channel types, and in particular certain T‐Type channels, may show sensitivity to dihydropyridine compounds. In this study, we synthesized a novel group of bis‐1,4‐dihydropyridines using the procedure reported by Dagnino that involved the condensation of n‐alkyl diacetoacetate (n = 2–7) with methyl‐3‐aminocrotonate and nitrophenylaldehyde. The synthesis was run under two conditions: (i) reflux and (ii) microwave. Calcium channels antagonist activity were determined in vitro using guinea‐pig ileum longitudinal smooth muscle assay. Synthesis of these compounds was confirmed with 1H‐NMR, IR and mass spectrometry. Then IC₅₀ of them are calculated and compared with Nifedipine. Finally, the result of this pharmacological assay was used in quantitative structure–activity relationship studies utilizing multiple linear regression analysis. Most of these compounds are less active compared with Nifedipine. Decrease in activity is the result of increase in steric hindrance. The quantitative structure–activity relationship study indicates that the activity is related to the electrostatic and topological parameters and the distance between two C5‐esteric groups of 1,4‐dihydropyridine rings.     

Design,Synthesis, and Biological Evaluation of Novel 4‐Aminopiperidinyl‐linked 3,5‐Disubstituted‐1,2,6‐thiadiazine‐1,1‐dione Derivatives as HIV‐1 NNRTIs

Based on the hybridization of the privileged fragments in DABO and DAPY‐typed HIV‐1 NNRTIs, a novel series of 4‐aminopiperidinyl‐linked 3,5‐disubstituted‐1,2,6‐thiadiazine‐1,1‐dione derivatives were designed, synthesized, and evaluated for their in vitro anti‐HIV activities in MT‐4 cells. Most of the target compounds showed weak inhibitory activity against WT HIV‐1. In order to confirm the mode of action of the target compounds, representative compounds Ba8 and Bb8 were selected to perform the HIV‐1 RT inhibitory assay. In this assay, Ba8 and Bb8 displayed good activity with IC₅₀ values of 3.15 and 1.52 μm , respectively. Additionally, preliminary structure–activity relationships (SARs) analysis and molecular docking studies of newly synthesized compounds are also discussed.     

Amino Acid Derivatives,Part 4: Synthesis and Anti‐HIV Activity of New Naphthalene Derivatives

A new series of 2‐(naphthalen‐2‐yloxy)‐N‐[(aryl‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐3‐yl)methyl] acetamides 5a–f was synthesized from naphthalene‐derived glycine derivative 2 via the hydrazinoacetamide analogs 4a–f . Alternatively, treatment of 4a with H₂SO₄ afforded 2‐(naphthalen‐2‐yloxy)‐N‐((5‐(phenylamino)‐1,3,4‐thiadiazol‐2‐yl)methyl) acetamide 6a . Alkylation or sulphonylation of 5a afforded the S‐alkylated derivatives 7 and 8 , respectively. Interestingly, treatment of 3 with methoxide ion gave the triazine derivative 9 . The synthesized compounds have been screened for their inhibitory activity against HIV‐1 and HIV‐2 in MT‐4 cells. However, 7 was found to be the potent inhibitor in vitro for the replication of HIV‐1 (EC₅₀ = 0.20 μg/mL), suggesting a new lead in the development of an antiviral agent.     

Synthesis and Biological Evaluation of Novel 5,8‐Disubstituted‐2‐methyl‐2,3,4,5‐tetrahydro‐1H‐pyrido[4,3‐b] indoles as 5‐HT6 and H1 Receptors Antagonists

Synthesis, biological evaluation, and structure‐activity relationships (SAR) for a series of novel γ‐carboline analogues of Dimebon are described. Among the studied compounds, tetrahydro‐γ‐carboline 5b (2,8‐dimethyl‐5‐[cis‐2‐pyridin‐3‐ylvinyl]‐2,3,4,5‐tetrahydro‐carboline) has been identified as the most potent small molecule antagonist, in particular against histamine H₁ and serotonin 5‐HT₆ receptors (IC₅₀ < 0.45 μM and IC₅₀ = 0.73 μM, respectively). A thorough comparative SAR study performed for the tested compounds has revealed significant correlations between the nature of side substituents and the related antagonistic activity.     

Synthesis and biological evaluation of novel imidazopyrimidin‐3‐amines as anticancer agents

Groebke–Blackburn–Bienayme reaction has been utilized for the synthesis of new imidazo[1,2‐a]pyrimidine derivatives as novel anticancer agents. The cytotoxic activities of compounds were evaluated against human cancer cell lines including MCF‐7, T‐47D, and MDA‐MB‐231, compared with etoposide as the standard drug. Among the tested compounds, hydroxy‐ and/or methoxy‐phenyl derivatives ( 6a–c and 6k ) with IC₅₀ values of 6.72–14.36 μm were more potent than etoposide against all cell lines. The acridine orange/ethidium bromide double staining and DNA fragmentation studies demonstrated that the cytotoxic effect of 3‐hydroxy‐4‐methoxyphenyl derivative 6c is associated with apoptosis in cancer cells.     

Synthesis and kinetics studies of N′‐(2‐(3,5‐disubstituted‐4H‐1,2,4‐triazol‐4‐yl)acetyl)‐6/7/8‐substituted‐2‐oxo‐2H‐chromen‐3‐carbohydrazide derivatives as potent antidiabetic agents

A novel series of N′‐(2‐(3,5‐disubstituted‐4H‐1,2,4‐triazol‐4‐yl)acetyl)‐6/7/8‐substituted‐2‐oxo‐2H‐chromen‐3‐carbohydrazides were synthesized and studied for their α‐glucosidase inhibition activity. Most of the synthesized compounds exhibited potential α‐glucosidase inhibition activity with IC₅₀ values ranging from 0.96 ± 0.02 to 32.86 ± 0.73 µg/ml. Among them, compounds 3e and 4e , having a methoxy group on the coumarin ring, proved to be the most potent ones, showing an enzyme inhibition activity with IC₅₀ = 0.96 ± 0.02 and 1.44 ± 0.06 µg/ml, respectively. The kinetic study through Lineweaver–Burk plots revealed that the inhibition mechanism of the most active compounds 3d, 3e, 4d , and 4e , on the α‐glucosidase activity, was found to be in the competitive mode.     

Design,synthesis, and evaluation of novel heteroaryldihydropyrimidine derivatives as non‐nucleoside hepatitis B virus inhibitors by exploring the solvent‐exposed region

In continuation of our efforts toward the discovery of potent non‐nucleoside hepatitis B virus (HBV) inhibitors with novel structures, we have explored the solvent‐exposed protein region of heteroaryldihydropyrimidine derivatives. Herein, the morpholine ring of GLS4 was replaced with substituted sulfonamides and triazoles to generate novel non‐nucleoside HBV inhibitors with desirable potency. In in vitro biological evaluation, several derivatives showed good anti‐HBV DNA replication activity compared to lamivudine. In particular, compound II‐1 displayed the most potent activity against HBV DNA replication (IC₅₀ = 0.35 ± 0.04 μM). The preliminary structure–activity relationships of the new compounds were summarized, which may help in discovering more potent anti‐HBV agents via rational drug design.