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Human tuberculosis (TB) is primarily caused by Mycobacterium tuberculosis (Mtb) that inhabits inside and amidst immune cells of the host with adapted physiology to regulate interdependent cellular functions with intact pathogenic potential. The complexity of this disease is attributed to various factors such as the reactivation of latent TB form after prolonged persistence, disease progression specifically in immunocompromised patients, advent of multi- and extensivelydrug resistant (MDR and XDR) Mtb strains, adverse effects of tailor-made regimens, and drug-drug interactions among anti-TB drugs and anti-HIV therapies. Thus, there is a compelling demand for newer anti-TB drugs or regimens to overcome these obstacles. Considerable multifaceted transformations in the current TB methodologies and molecular interventions underpinning hostpathogen interactions and drug resistance mechanisms may assist to overcome the emerging drug resistance. Evidently, recent scientific and clinical advances have revolutionised the diagnosis, prevention, and treatment of all forms of the disease. This review sheds light on the current understanding of the pathogenesis of TB disease, molecular mechanisms of drug-resistance, progress on the development of novel or repurposed anti-TB drugs and regimens, host-directed therapies, with particular emphasis on underlying knowledge gaps and prospective for futuristic TB control programs.

A series of some novel (E)-2-methyl/propyl-4-[(2-(substitutedbenzylidene)hydrazinyl]-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines was synthesized and characterized by adopting an appropriate synthetic scheme. The effect of electron withdrawing and electron donating groups at the aromatic ring in presence of methyl and propyl substituents at the 2-position of the scaffold was evaluated for anthelmintic activity against adult Indian earthworms (Pheretima posthuma). Among 2-methyl-thieno[2,3-d]pyrimidine analogs, compounds with electron donating methoxy group either at para-position or at meta and para-positions of the aromatic ring showed potent anthelmintic activity at 100 μg/ml (284 and 261.8 μM concentrations) for compounds 5g and 5h with a mean paralytic time of 2.32, 2.22 min, and helminthicidal time of 22.38, 19.43 min, respectively. In contrast, the presence of electron withdrawing chloro group at ortho and para-position of the aromatic ring was found to be favorable for the anthelminthic activity of the compounds 5n and 5o (at concentration of 259.7 μM) with propyl group at the 2-position of the thieno[2,3-d]pyrimidine scaffold, exhibiting mean paralytic time of 2.5 min, 2.81 min and helminthicidal time of 21, 20.03 min, respectively. Anthelmintic activities of these four compounds 5g, 5h, 5n, and 5o (at the concentrations of 284, 261.8, 259.7, and 259.7 μM, respectively) were found to be on par with the standard drug piperazine adipate (time for paralysis and death at 6.25 and 24.5 min, respectively) at concentration of 100 μg/ml (431.03 μM). Overall, the potency of these compounds (5g, 5h, 5n, and 5o) is better than standard drug as they exhibited the same activity at 259.7–284 μM as that of a standard drug (which has shown the same activity at 431.03 μM). Further, the predicted ADME properties of all the synthesized compounds were found to be in the satisfactory ranges as predicted by SwissADME software and found to have drug-like properties. Thus, further modification of these compounds might lead to the discovery of more potent analogs.

The cyclooxygenase-2 (COX-2) enzyme is an important target for drug discovery and development of novel anti-inflammatory agents. Selective COX-2 inhibitors have the advantage of reduced side-effects, which result from COX-1 inhibition that is usually observed with nonselective COX inhibitors. In this study, the design and synthesis of a new series of 7-methoxy indolizines as bioisostere indomethacin analogues (5a–e) were carried out and evaluated for COX-2 enzyme inhibition. All the compounds showed activity in micromolar ranges, and the compound diethyl 3-(4-cyanobenzoyl)-7-methoxyindolizine-1,2-dicarboxylate (5a) emerged as a promising COX-2 inhibitor with an IC50 of 5.84 µM, as compared to indomethacin (IC50 = 6.84 µM). The molecular modeling study of indolizines indicated that hydrophobic interactions were the major contribution to COX-2 inhibition. The title compound diethyl 3-(4-bromobenzoyl)-7-methoxyindolizine-1,2-dicarboxylate (5c) was subjected for single-crystal X-ray studies, Hirshfeld surface analysis, and energy framework calculations. The X-ray diffraction analysis showed that the molecule (5c) crystallizes in the monoclinic crystal system with space group P 21/n with a = 12.0497(6)Å, b = 17.8324(10)Å, c = 19.6052(11)Å, α = 90.000°, β = 100.372(1)°, γ = 90.000°, and V = 4143.8(4)Å3. In addition, with the help of Crystal Explorer software program using the B3LYP/6-31G(d, p) basis set, the theoretical calculation of the interaction and graphical representation of energy value was measured in the form of the energy framework in terms of coulombic, dispersion, and total energy.

A series of ethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-3-carboxylates 4a&ndash, f and dimethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylates 4g&ndash, k have been synthesized and evaluated for their anti-tubercular (TB) activities against H37Rv (American Type Culture Collection (ATCC) strain 25177) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis by resazurin microplate assay (REMA). Molecular target identification for these compounds was also carried out by a computational approach. All test compounds exhibited anti-tuberculosis (TB) activity in the range of 8&ndash, 128 &micro, g/mL against H37Rv. The test compound dimethyl-1-(4-fluorobenzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylate 4j emerged as the most promising anti-TB agent against H37Rv and multidrug-resistant strains of Mycobacterium tuberculosis at 8 and 16 &micro, g/mL, respectively. In silico evaluation of pharmacokinetic properties indicated overall drug-likeness for most of the compounds. Docking studies were also carried out to investigate the binding affinities as well as interactions of these compounds with the target proteins.

Acetylcholine is a neurotransmitter that plays a significant role in a variety of physiological functions. Cholinergic neurons synthesize, store, and release acetylcholine and are also responsible for sympathetic and parasympathetic responses of the autonomous nervous system. The wide range of functions that the cholinergic system plays explains the diverse range of therapeutic potential that targets this system. Over the decades, cholinergic and anticholinergic drugs are utilized as treatment options for various conditions including ophthalmology, neurogenic bladder, myasthenia gravis, dementia, postoperative urinary retention, xerostomia, anticholinergic overdose, snakebites, Parkinson’s disease, and Alzheimer’s disease. Alongside, they are also investigated for various promising therapeutics. This chapter provides an overview of the cholinergic system pharmacology, functions in the body, cholinergic and anticholinergic compounds, and their potential role in the medical field. Further, the chapter highlights the updates on the cholinergic compounds currently used to treat various conditions as well as compounds under investigation.

A series of novel 7-amino-5-oxo-2-substituted-aryl/hetero-aryl-5,8-dihydro[1,2,4]triazolo[1,5-a]pyridine-6-carbonitriles (4a-4t) was synthesized, characterized and evaluated for their binding affinity and selectivity towards hA1 , hA2A , hA2B and hA3 adenosine receptors (ARs). Compound 4a with a phenyl ring at 2-position of the triazolo moiety of the scaffold showed high affinity and selectivity for hA1 AR (Ki hA1 = 0.076 μM, hA2A = 25.6 μM and hA3 > 100 μM). Introduction of various electron donating and withdrawing groups at different positions of the phenyl ring resulted in drastic reduction in affinity and selectivity towards all the ARs, except compound 4b with a 4-hydroxyphenyl group at 2-position. Interestingly, the replacement of the phenyl ring with a smaller heterocyclic thiophene ring (π excessive system) resulted in further improvement of affinity for hA1 AR of compound 4t (Ki hA1 = 0.051 μM, hA2A = 9.01 μM and hA3 > 13.9 μM) while retaining the significant selectivity against all other AR subtypes similar to compound 4a. The encouraging results for compounds 4a and 4t indicate that substitution at 2-position of the scaffold with π-excessive systems other than thiophene may lead to even more potent and selective hA1 AR antagonists.

A rapid synthesis of a series of new 5,6-dimethyl-7-phenyl-2-alkyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidinones and 5,6-dimethyl-7-benzyl-2-alkyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidinones was accomplished in good yields using microwave irradiation under base catalysis.

A series of alkyl- and aryl-1,2,4-triazino[4,3-c]quinazolines (5a-h and 8a-h) were synthesized and characterized. The title compounds were evaluated for their in vivo bronchodilator activity on guinea pigs. All the test compounds exhibited good protection against histamine-induced bronchospasm. The structure-activity relationships based on the results obtained for these series were studied. Incorporation of an aryl ring with halo substitution to the theophylline bioisostere increases its potency. Among the compounds tested, 5b was found to be the most potent with 88.7% protection against histamine-induced bronchospasm compared to the standard compound aminophylline (87.8%).

A rapid synthesis of a series of new 5,6-dimethyl-7-phenyl-2-alkyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidinones and 5,6-dimethyl-7-benzyl-2-alkyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidinones was accomplished in good yields using microwave irradiation under base catalysis.