Cycloaddition reactions of cross-conjugated enaminones

Novel benzoic acid derivatives: Synthesis and biological evaluation as multitarget acetylcholinesterase and carbonic anhydrase inhibitors

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by dementia, memory impairment, cognitive dysfunction, and speech impairment. The utility of cholinergic replacement by acetylcholinesterase (AChE) inhibitors in AD treatment has been well documented so far. Recently, studies have also evidenced that human carbonic anhydrases (hCAs) serve as an important target for AD treatment. In this direction, the improvement of new multitarget drugs, which can simultaneously modulate several mechanisms or targets included in the AD pathway, may be a potent strategy to treat AD. In light of these data for understanding and developing AD-related multitarget AChE and hCAs inhibitors, in this study, novel methylene-aminobenzoic acid and tetrahydroisoquinolynyl-benzoic acid derivatives (4a-g and 6a-g) were designed. The synthesized analogs were experimentally validated for their effects by in vitro and direct enzymatic tests. Also, the compounds were subjected to in silico monitoring with Schrödinger Suite software to assign binding affinities of potential derivatives based on Glide XP scoring, molecular mechanics-generalized Born surface area computing, and validation by molecular docking. The results revealed that 6c (1,3-dimethyldihydropyrimidine-2,4-(1H,3H)-dione-substituted, K_I  value of 33.00 ± 0.29 nM), 6e (cyclohexanone-substituted, K_I  value of 18.78 ± 0.09 nM), and 6f (2,2-dimethyl-1,3-dioxan-4-one-substituted, K_I  value of 13.62 ± 0.21 nM) from the benzoic acid derivatives in this series were the most promising derivatives, as they exhibited a good multifunctional inhibition at all experimental levels and in the in silico validation against hCA I, hCA II, and AChE, respectively, for the treatment of AD.

Novel thioureido-benzenesulfonamide derivatives with enaminone linker as potent anticancer, radiosensitizers and VEGFR2 inhibitors

In this study, novel series of thioureido-benzenesulfonamide derivatives bearing an enaminone linker either meta or para oriented and having terminal linear or substituted aromatic or heteroaromatic ring system 5-16a,b were designed and synthesized based on the general pharmacophoric features of type II VEGFR2 inhibitors. Evaluation of the synthesized compounds against HEPG2 hepatocellular carcinoma cells in vitro identified compounds 5b, 6b and 10-13b as most active anticancer agents with IC50 equal to 0.12, 0.29, 0.58, 0.44, 0.42 and 0.66 µM, respectively. These compounds were evaluated for their ability to in vitro inhibit VEGFR2 kinase enzyme. The results demonstrated highly potent dose-related VEGFR2 inhibition with IC50 values in nanomolar range (33, 57, 210, 37, 37 and 220 nM, respectively). The radiosensitizing ability of the most promising compounds was studied which showed an increase in the cell killing effect of radiation after combination with the synthesized compounds which revealed lowered IC50 by nearly 50%. Molecular docking for the most potent compounds was performed to predict their possible binding mode within VEGFR2 active site and they showed binding affinity in a similar way to sorafenib.

Regioselectivity and diastereoselectivity of three-component reaction of α-amino acid, dialkyl acetylenedicarboxylates and 2-arylidene-1,3-indanediones

The 1,3-dipolar cycloaddition of active azomethine ylide, which were generated in situ from addition reaction of α-amino acids with dialkyl acetylenedicarboxylates, with 2-arylidene-1,3-indanediones showed versatile regioselectivity and diastereoselectivity. The reaction of sarcosine and glycine afforded one kind of functionalized spiro[indene-2,3'-pyrrolidines]. The other primary α-amino acids such as alanine, phenylalanine and leucine gave another kind of regioisomeric spiro[indene-2,3'-pyrrolidines]. The cyclic α-amino acids resulted in the corresponding spiro[indene-2,2'-pyrrolizines] and [indene-2,6'-pyrrolo[1,2-c]thiazoles].

Convenient synthesis of functionalized pyrrolo[3,4-b]pyridines and pyrrolo[3,4-b]quinolines via three-component reactions

A simple protocol for convenient construction of pyrrolo[3,4-b]pyridine skeleton was successfully developed by base promoted three-component reaction of β-enamino imide, aromatic aldehydes and malononitrile as well as its ester and amide derivatives.

Triflic acid promoted fries rearrangement of C-3 vinyl/isopropenyl-azetidin-2-ones: single-pot synthesis of C-3 functionalized-2-aryl-2,3-dihydro-quinoline-4(1H)-ones

Single-pot synthesis of C-3 functionalized-2-aryl-2,3-dihydro-quinoline-4(1H)-ones with stability profile validation using density functional theory (DFT) calculations.

Synthesis of 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via Four-component reactions of aromatic aldehydes, cyclic 1,3-carbonyls, arylamines, and dimethyl acetylenedicarboxylate

A protocol has been developed for the efficient synthesis of structurally diverse 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via four-component reactions of arylamines, acetylenedicarboxylate, aromatic aldehydes and cyclic 1,3-diketones. The selective formation of the very different pyridinone or pyran derivatives depends on the structure of cyclic 1,3-diketone. The key steps are proposed to involve Michael addition of the enamino ester formed in situ from the reaction of arylamine with dimethyl acetylenedicarboxylate to arylidine cyclic 1,3-diketones.