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Efforts have been devoted for the discovery and development of positive allosteric modulators (PAMs) of 5-HT 2C R because of their potential advantages over the orthosteric agonist like Lorcaserin that was withdrawn from the market. On the other hand, pursuing a positive ago-allosteric modulator (PAAM) is considered as beneficial particularly when an agonist is not capable of affecting the potency of the endogenous agonist sufficiently. In search of a suitable PAAM of 5-HT 2C R we adopted an in silico based approach that indicated the potential of the 3-(1-hydroxycycloalkyl) substituted isoquinolin-1-one derivatives against the 5-HT 2C R as majority of these molecules interacted with the site other than that of Lorcaserin with superior docking scores. These compounds along with the regioisomeric 3-methyleneisoindolin-1-one derivatives were prepared via the Cu(OAc) 2 catalyzed coupling of 2-iodobenzamide with 1-ethynylcycloalkanol under ultrasound irradiation. According to the in vitro studies, most of these compounds were not only found to be potent and selective agonists but also emerged as PAAM of 5-HT 2C R whereas Lorcaserin did not show PAAM activities. According to the SAR study the isoquinolin-1(2H)-ones appeared as better PAAM than isoindolin-1-ones whereas the presence of hydroxyl group appeared to be crucial for the activity. With the potent PAAM activity for 5-HT 2C R (EC 50  = 1 nM) and 107 and 86-fold selectivity towards 5-HT 2C over 5-HT 2A and 5-HT 2B the compound 4i was identified as a hit molecule. The compound showed good stability in male BALB/c mice brain homogenate (∼85 % remaining after 2 h), moderate stability in the presence of rat liver microsomes (42 % remaining after 1 h) and acceptable PK properties with fast reaching in the brain maintaining ∼ 1:1 brain/plasma concentration ratio. The compound at a dose of 50 mg/kg exhibited decreased trend in the food intake starting from day 3 in S.D. rats, which reached significant by 5th day, and the effect was comparable to Lorcaserin (10 mg/kg) on day 5. Thus, being the first example of PAAM of 5-HT 2C R the compound 4i is of further medicinal interest., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

A series of indole based novel Schiff bases was designed as potential agonists of 5-HT 2C receptor that was supported by docking studies in silico. These compounds were synthesized via Amberlyst-15 catalysed condensation of an appropriate pyrazole based primary amine with the corresponding indole-3-aldehyde under ultrasound irradiation at ambient temperature. A number of target Schiff bases were obtained in good yields (77-87%) under mild conditions within 1 h. Notably, the methodology afforded the corresponding pyrazolo[4,3-d]pyrimidin-7(4H)-one derivatives when the primary amine was replaced by a secondary amine. Several Schiff bases showed agonist activity when tested against human 5-HT 2C using luciferase assay in HEK293T cells in vitro. The SAR (Structure-Activity-Relationship) studies suggested that the imine moiety was more favorable over its cyclic form i.e. the corresponding pyrazolopyrimidinone ring. The Schiff bases 3b (EC 50 1.8 nM) and 3i (EC 50 5.7 nM) were identified as the most active compounds and were comparable with Lorcaserin (EC 50 8.5 nM). Also like Lorcaserin, none of these compounds were found to be PAM of 5-HT 2C . With ∼24 and ∼150 fold selectivity towards 5-HT 2C over 5-HT 2A and 5-HT 2B respectively the compound 3i that reduced locomotor activity in zebrafish (Danio rerio) larvae model emerged as a promising hit molecule for further study., (Copyright © 2021 Elsevier Inc. All rights reserved.)

An improved and rapid synthesis of mefenamic acid based indole derivatives has been achieved via the ligand free Cu-catalyzed coupling-cyclization method under ultrasound irradiation. This simple, straightforward and inexpensive one-pot method involved the reaction of a terminal alkyne derived from mefenamic acid with 2-iodosulfanilides in the presence of CuI and K 2 CO 3 in PEG-400. The reaction proceeded via an initial CC bond formation (the coupling step) followed by CN bond formation (the intramolecular cyclization) to afford the mefenamic acid based indole derivatives in good to acceptable yields. Several of these compounds showed inhibition of PDE4 in vitro and the SAR (Structure Activity Relationship) within the series is discussed. The compound 3d has been identified as a promising and selective inhibitor of PDE4B (IC 50  = 1.34 ± 0.46 µM) that showed TNF-α inhibition in vitro (IC 50  = 5.81 ± 0.24 µM) and acceptable stability in the rat liver microsomes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Light-responsive nanoliposomes are being reported to induce cancer cell death through heat and reactive oxygen species (ROS). Nanoliposomes (CIR NLPs) encapsulating a near-infrared (NIR) light-sensitive dye, IR780, and a bioactive chlorophyll-rich fraction of Anthocephalus cadamba (CfAc) were synthesized and characterized. These CIR NLPs, when activated by NIR light, displayed localized synergistic cancer cell death under in vitro and in vivo conditions. We demonstrated a NIR light-mediated release of CfAc in cancer cells. The bioactive CfAc was selective in causing ROS generation (leading to autophagic cell death) in cancer cells, while normal healthy cells were unaffected. An increase in the intracellular ROS leading to enhanced lipidation of microtubule-associated protein light chain 3 (LC3-II) was observed only in cancer cells, while normal cells showed no increase in either ROS or LC3-II. In vivo analysis of CIR NLPs in an orthotopic mouse model showed better anti-tumorigenic potential through a combined effect (i.e. via heat and CfAc). We reported for the first time induction of selective and localized, bioactive phyto fraction-mediated autophagic cancer cell death through an NIR light trigger. The synergistic activation of ROS-mediated autophagy by light-triggered nanoliposomes can be a useful strategy for enhancing the anticancer potential of combinational therapies.

The chorismate mutase (CM) is considered as an attractive target for the identification of potential antitubercular agents due to its absence in animals but not in bacteria. A series of 3-indolylmethyl substituted pyrazolotriazinone derivatives were designed and docked into CM in silico as potential inhibitors. These compounds were efficiently synthesized using the Pd/Cu-catalyzed coupling-cyclization in a single pot involving the construction of indole ring. The methodology was later extended to the preparation of corresponding benzo analogs of pyrazolotriazinones i.e. 3-indolylmethyl substituted benzotriazinone derivatives. Several of these novel compounds showed significant inhibition of CM when tested in vitro at 30 µM. The SAR (Structure-Activity-Relationship) studies suggested that benzotriazinone moiety was more favorable over the pyrazolotriazinone ring. The two best active compounds showed IC 50  ∼ 0.4-0.9 µM (better than the reference/known compounds used) and no toxicity till 30 µM in vitro., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A new class of PDE4 inhibitors were designed and synthesized via the InCl 3 mediated heteroarylation of indoles and their further derivatization through the Pd(II)-catalyzed CH activation strategy. This effort allowed us to discover a series of 2-(1H-indol-3-yl)-quinoxaline based inhibitors possessing PDE4B selectivity over PDE4D and PDE4C. One of these compounds i.e. 3b (PDE4B IC 50  = 0.39 ± 0.13 μM with ∼27 and > 250 fold selectivity for PDE4B over PDE4D and C, respectively) showed effects in Zebrafish experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis when dosed at 3, 10 and 30 mg/kg intraperitoneally. Indeed, it halted the progression of the disease across all these doses tested. At an intraperitoneal dose of 30 mg/kg the compound 3b showed promising effects in adjuvant induced arthritic rats. The compound reduced paw volume, inflammation and pannus formation (in the knee joints) as well as pro-inflammatory gene expression/mRNA levels significantly in arthritic rats. Moreover, this compound was found to be selective towards PDE4 over other families of PDEs in vitro and safe when tested for its probable toxicity (e.g. teratogenicity, hepatotoxicity and cardiotoxicity) in Zebrafish., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Background: The indolo[2,3-b]quinoline framework is often found in various natural products displaying a range of pharmacological activities. This is an attractive template for the design and discovery of potential drugs especially for the identification of new anticancer agents., Methods: The synthesis of 6-substituted indolo[2,3-b]quinolones was undertaken and carried out using a ultrasound assisted method involving two sequential C-N bond forming reactions between 3-(2- bromophenyl)-2-chloroquinoline and amines in a single pot in the presence of Pd(OAc)2 and a ligand (S)-BINAP. All the synthesized compounds were tested in vitro against two cancer cell lines e.g. MCF7 and HepG2 along with non-cancerous HEK293 cell lines., Results: Two of these compounds showed promising and selective growth inhibition of MCF7 cell lines and one induced significant apoptosis in cancer (MCF7) cells., Conclusion: Compounds based on indolo[2,3-b]quinolone framework may be useful for the identification of new cytotoxic agents thereby potential cure for breast cancer., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

TFA alone was found to be remarkably effective for the intramolecular hydroarylation (IMHA) of alkynes when employed as a solvent in the cyclization of 3-alkynyl substituted 2-(indol-3-yl)quinoxalines. This simple and metal free cyclization method afforded a range of indolophenazines as new and potential cytotoxic agents. The use of excess TFA was found to be crucial for the success of this reaction.

A strategy based on Pd-mediated ring closure of 1,2-disubstituted indoles containing an unactivated olefin leading to indole-1,2-fused 8- and 9-membered rings has been developed for the identification of new and potential scaffolds for apoptosis. A large number of fused indole derivatives containing an endocyclic double bond were synthesized using this robust methodology. A representative compound showed promising apoptotic properties in zebrafish embryos.

A number of 2H-1,3-benzoxazin-4(3H)-one derivatives containing indole or benzofuran moieties were synthesized by using Pd/C-Cu mediated coupling-cyclization strategy as a key step. The o-iodoanilides or o-iodophenol were coupled with 3-{2-(prop-2-ynyloxy)ethyl}-2H-benzo[e][1,3]oxazin-4(3H)-one using 10%Pd/C-CuI-PPh3 as a catalyst system and Et3N as a base to give the target compounds. All the synthesized compounds were tested for their PDE4B inhibitory potential in vitro using a cell based cAMP reporter assay. Some of them showed fold increase of the cAMP level when tested at 30 μM. A representative compound showed encouraging PDE4B inhibitory properties that were supported by its docking results., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Unprecedented synthesis of functionalized indoles of potential pharmacological interest has been developed via a Pd-mediated cascade reaction involving an intramolecular Heck coupling followed by the construction of a fused cyclopentane ring in a single pot.

A new, versatile and direct Pd-mediated method involving intramolecular cyclization of N-(2-iodoaryl)-N-(1-alkyl-1H-indol-2-yl)alkane/arene/heteroarene sulfonamide has been developed leading to a diverse and unique class of indolo[2,3-b]indoles for the potential inhibition of sirtuins.

Novel N-indolylmethyl substituted spiroindoline-3,2'-quinazolines were designed as potential inhibitiors of SIRT1. These compounds were synthesized in good yields by using Pd/C-Cu mediated coupling-cyclization strategy as a key step involving the reaction of 1-(prop-2-ynyl)-1'H-spiro[indoline-3,2'-quinazoline]-2,4'(3'H)-dione with 2-iodoanilides. Some of the compounds synthesized have shown encouraging inhibition of Sir 2 protein (a yeast homologue of mammalian SIRT1) in vitro and three of them showed dose dependent inhibition of Sir 2. The docking results suggested that the benzene ring of 1,2,3,4-tetrahydroquinazolin ring system of these molecules occupied the deep hydrophobic pocket of the protein and one of the NH along with the sulfonyl group participated in strong H-bonding interaction with the amino acid residues., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A conceptually new and straightforward introduction of sulfonyl groups at the C-7 position of an indole ring has been achieved via AlCl(3) mediated unexpected regioselective sulfonyl group migration for N-alkyl/aryl/heteroarylsulfonyl indoles affording potential inhibitors of Mycobacterium tuberculosis H37Rv chorismate mutase.

A new one-pot synthesis of 2-(hetero)aryl indoles via sequential C-C coupling followed by C-Si bond cleavage and a subsequent tandem C-C/C-N bond forming reaction is described. A variety of functionalized indole derivatives were prepared by conducting this four step reaction under Pd/C-Cu catalysis. The methodology involved coupling of (trimethylsilyl)acetylene with iodoarenes in the presence of 10% Pd/C-CuI-PPh(3) and triethylamine in MeOH, followed by treating the reaction mixture with K(2)CO(3) in aqueous MeOH, and finally coupling with o-iodoanilides. The single crystal X-ray data of a synthesized indole derivative is presented. Application of the methodology, in vitro pharmacological properties of the synthesized compound, along with a docking study is described.

3-Methylindole is acylated regioselectively at the methyl group when treated with a variety of acyl chlorides in 1,2-dichloroethane in the presence of AlCl(3), affording a mild and direct method for the synthesis of 3-(2-oxoalkyl)indoles. The product formation in this one-pot reaction largely depends on the conditions of the reaction employed. The methodology does not require protection-deprotection steps and is amenable for the scale-up synthesis of these indole derivatives.