carried out chemical syntheses. toward AChE. The present data indicate that compounds 2, 7, 17, 18, and 36 may represent attractive multipotent molecules for the potential treatment of Alzheimers disease. = 8.4 Hz, 1H) and 7.22 (d, 1H, = 8.4 Hz, CH), corresponding to H5 and H6, in the 1H NMR spectrum of compound 20, as well PB1 as two singlets at 7.53 and 2.76, integrating for one and three protons, and corresponding to H5 and C(7)CH3, respectively, in the 1H NMR spectrum of compound 21, clearly support the structure of the Friedl?nder products. The formation of major reaction product 20, as the result of a preferred intramolecular cyclization through the methyl versus the methylene group, leading to major C-7 susbtituted [1,8]naphthyridine, is also in good agreement with previous results reported in the literature from similar reagents using the same catalyst.49 Open in a separate window Scheme 5 Reaction conditions: (a) Pyrrolidine, CH2Cl2/MeOH. The syntheses of pyrazolo[3,4-( 0.05) prevented by compounds 2, 7, and 13 (10 M), whereas compounds 3 and 6 displayed a slightly neuroprotective effect against A. In contrast, compounds 4, 5, and 12 did not protect against A1C42 neurotoxicity (Figure ?(Figure4A). We4A). We have also tested the potential neuroprotective role of compounds 14C18 (2.5 M) and 35C37 (5 M) against A1C42, incubated for 24 h (Figure ?(Figure4B).4B). As can be seen in Figure ?Figure4B4B only compounds 17, 18, 35, and 36 were able to prevent A-neurotoxicity ( 0.05). Compounds 14C16 and 37 caused a slight protection without statistical significance ( 0.05). Open in a separate window Figure 4 Assessment of the neuroprotective effect of phenoxyalkylamino-4-phenylnicotinates (2C7) and phenoxyalkoxybenzylidenemalononitriles (12,13) (A), as well as of pyridonepezils (14C18) and pyrazolo[3,4- 0.05) reduction in the AChE activity, whereas compound 6 did not affect significantly this enzyme (Figure ?(Figure5A).5A). All compounds were effective in preventing the enhancement of AChE activity Tinostamustine (EDO-S101) induced by A1C42, which is the AChE activity in neurons challenged to A1C42. The pyridonepezils Tinostamustine (EDO-S101) 17 and 18 decreased the activity by 50% and 30%, respectively, whereas compound 16 caused a significant reduction of about 12% in AChE activity of cells challenged to A1C42. Regarding the pyrazolo[3,4- 0.05) inhibition in AChE, preventing the upregulation of this enzyme induced by A1C42 (Figure ?(Figure55B). Open in a separate window Figure 5 Assessment of the phenoxyalkylamino-4-phenylnicotinates (2C7) and phenoxyalkoxybenzylidenemalononitriles (12,13) (A), as well as pyridonepezils (14C18) and pyrazolo[3,4-homeostasis are implicated in Tinostamustine (EDO-S101) diverse disease processes and have become a major focus of study in multifactorial neurodegenerative disorders such as AD. Since no cure is currently known, targeting Cadyshomeostasis as an underlying and integral component of AD pathology may result in novel and effective treatments for AD.32 The phenoxyalkylamino-4-phenylnicotinates (2,3,7), the phenoxyalkoxybenzylidenemalononitriles (12,13), the pyridonepezils (16C18), and the pyrazolo[3,4-levels, so when these cells were K+-depolarized the influx of Ca2+ was lower than in control cells and the effects of compounds were not detectable (data not shown) . However, when compounds 2, 7, 12, 13, 17, 18, and 36 were tested in control cells, it was observed that they significantly prevented the Cainflux evoked by KCl (50 mM) depolarization, suggesting that these set of compounds can act as antagonists of VSCC. Open in a separate window Figure 6 Influx of Ca2+ triggered by KCl Tinostamustine (EDO-S101) (50 mM) depolarization in neuronal cells (SH-SY5Y) in the presence of compounds 2, 3, 7, 12, 13, 16C18, and 35C37. Control cells were treated with 0.1% DMSO, the compound vehicle. The intracellular Ca2+ levels were measured, using the fura-2 fluorescent dye, and the fluorescence was measured Tinostamustine (EDO-S101) at of 340, 380 excitation and 510 nm emission (see Methods). The Ca2+ influx was calculated as the difference between peak of fura-2 fluorescence upon depolarization and the basal fura-2 fluorescence. Data are mean SEM of three to four independent experiments and expressed as arbitrary units (a.u.) of fluorescence. Previous studies also demonstrated donepezil might have a neuroprotective effect by inhibition of Ca2+ channels, as it was reported to inhibit the high potassium-induced [Ca2+]i rise at high concentrations59 and block voltage-gated calcium channels.