Design and Synthesis of New Pyrimidine-Quinolone Hybrids as Novel hLDHA Inhibitors

Abstract

A battery of novel pyrimidine-quinolone hybrids was designed by docking scaffold replacement as lactate dehydrogenase A (hLDHA) inhibitors. Structures with different linkers between the pyrimidine and quinolone scaffolds (10-21 and 24–31) were studied in silico, and those with the 2-aminophenylsulfide (U-shaped) and 4-aminophenylsulfide linkers (24–31) were finally selected. These new pyrimidine-quinolone hybrids (24–31)(a–c) were easily synthesized in good to excellent yields by a green catalyst-free microwave-assisted aromatic nucleophilic substitution reaction between 3-(((2/4-aminophenyl)thio)methyl)quinolin-2(1H)-ones 22/23(a–c) and 4-aryl-2-chloropyrimidines (1–4). The inhibitory activity against hLDHA of the synthesized hybrids was evaluated, resulting IC50 values of the U-shaped hybrids 24–27(a–c) much better than the ones of the 1,4-linked hybrids 28–31(a–c). From these results, a preliminary structure–activity relationship (SAR) was established, which enabled the design of novel 1,3-linked pyrimidine-quinolone hybrids (33–36)(a–c). Compounds 35(a–c), the most promising ones, were synthesized and evaluated, fitting the experimental results with the predictions from docking analysis. In this way, we obtained novel pyrimidine-quinolone hybrids (25a, 25b, and 35a) with good IC50 values (<20 μM) and developed a preliminary SAR.

Synthesis and hLDH Inhibitory Activity of Analogues to Natural Products with 2,8-Dioxabicyclo[3.3.1]nonane Scaffold

“…The enzymatic assay was conducted on 96-well microplates and the decrease in the β-NADH fluorescence (λ excitation = 340 nm; λ emission = 460 nm) was detected in a TECAN Infinite 200 Pro M Plex fluorescent plate reader (Tecan Instrument, Inc.) at 28 °C. The activity was determined according to our previously described protocol [ 34 , 35 ]. The final volume in each well was set to 200 µL using 100 mM potassium phosphate buffer, 0.041 units/mL LDHA, 155 µM β-NADH, 1 mM pyruvate (saturated conditions), and DMSO solutions (5%, v / v ) of pure compounds at concentrations in the range of 1–600 µM.…”

“…The fact that these compounds have emerged as a new family of hLD selective inhibitors [35], encouraged us to systematically design a series of 2,8-dioxab clo[3.3.1]nonane compounds in order to gain insight into the structural requirements are responsible for hLDHA activity and hLDHA/hLDHB selectivity. In that sense, 44 b clic derivatives (1-6; 42-70) (35 are new compounds) have been prepared by reaction tween 9 different flavylium salts (27)(28)(29)(30)(31)(32)(33)(34)(35) (3 are new compounds), with modifications a and B-rings, and phloroglucinol (36) and other non-phenolic π-nucleophiles (37 (Scheme 1). Nucleophiles 36-38 are commercially available, but pyrone-type compou 39-41 have been prepared as racemic mixtures according to a previously reported m odology by reaction of the proper benzaldehyde derivative and ethyl acetoacetate [48 The yields obtained and the spectroscopic data of these pyrone derivatives are consis with the reported ones (39 (88%) [48], 40 (80%) [48], and 41 (74%) [48,50]).…”

“…In any case, a combined treatment with both types of pharmacological agents could have synergistic effect and benefits, such as lowering the required doses or the frequency of administration. Actually, approaches based on attenuated expression of LDHA or inhibition of LDHA activity by small-molecule drugs appear as emerging strategies for the treatment of these diseases [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. Pharmaceutical companies and researchers in academia are investing significant efforts to identify natural or synthetic h LDHA inhibitors with a huge structural variability.…”

“…Our research group is also interested in the development of h LDHA inhibitors as a pharmacological option for the treatment of PHs, a rare life-threatening genetic disease [ 34 , 35 ]. We recently reported the detection of (±)-2,8-dioxabicyclo[3.3.1]nonane derivatives, analogues to A-type proanthocyanidin natural products, as a new family of h LDHA inhibitors [ 35 ].…”

Proanthocyanidins in Pruning Wood Extracts of Four European Plum (Prunus domestica L.) Cultivars and Their hLDHA Inhibitory Activity

“…However, nowadays, several pharmacological strategies are under study for the treatment of PHs [33] . One of them is the direct inhibition of human hepatic isozyme Lactate Dehydrogenase A ( h LDHA), which is in charge of the transformation of glyoxylate into oxalate, by small synthetic molecules [34–38] . In addition, some natural products and plant extracts rich in phenolic compounds (phenylpropanoids, flavonoids and procyanidins) have been studied for their ability to inhibit h LDHA, [39–41] although it is a field still poorly explored.…”