163461-20-9Relevant academic research and scientific papers
Antimalarial Pyrido[1,2- a]benzimidazole Derivatives with Mannich Base Side Chains: Synthesis, Pharmacological Evaluation, and Reactive Metabolite Trapping Studies
Okombo, John,Brunschwig, Christel,Singh, Kawaljit,Dziwornu, Godwin Akpeko,Barnard, Linley,Njoroge, Mathew,Wittlin, Sergio,Chibale, Kelly
, p. 372 - 384 (2019/01/26)
A novel series of pyrido[1,2-a]benzimidazoles bearing Mannich base side chains and their metabolites were synthesized and evaluated for in vitro antiplasmodium activity, microsomal metabolic stability, reactive metabolite (RM) formation, and in vivo antimalarial efficacy in a mouse model. Oral administration of one of the derivatives at 4 × 50 mg/kg reduced parasitemia by 95% in Plasmodium berghei-infected mice, with a mean survival period of 16 days post-treatment. The in vivo efficacy of these derivatives is likely a consequence of their active metabolites, two of which showed potent in vitro antiplasmodium activity against chloroquine-sensitive and multidrug-resistant Plasmodium falciparum (P. falciparum) strains. Rapid metabolism was observed for all the analogues with 40% of parent compound remaining after 30 min of incubation in liver microsomes. RM trapping studies detected glutathione adducts only in derivatives bearing 4-aminophenol moiety, with fragmentation signatures showing that this conjugation occurred on the phenyl ring of the Mannich base side chain. As with amodiaquine (AQ), interchanging the positions of the 4-hydroxyl and Mannich base side group or substituting the 4-hydroxyl with fluorine appeared to block bioactivation of the AQ-like derivatives though at the expense of antiplasmodium activity, which was significantly lowered.
Antiplasmodial imidazopyridazines: structure-activity relationship studies lead to the identification of analogues with improved solubility and hERG profiles
Cheuka, Peter Mubanga,Lawrence, Nina,Taylor, Dale,Wittlin, Sergio,Chibale, Kelly
, p. 1733 - 1745 (2018/10/26)
3,6-Diarylated imidazopyridazines have recently been shown to possess good in vitro antiplasmodial and in vivo antimalarial activity. However, frontrunner compounds have been associated with poor solubility and a hERG (human ether-a-go-go-related gene) inhibition liability raising concerns for potential cardiotoxicity risks. Herein, we report the synthesis and structure-activity relationship studies of new imidazopyridazines aimed at improving aqueous solubility and countering hERG inhibition while maintaining antiplasmodial potency. While we identified new analogues with potent antiplasmodial activity (IC50 = 0.031 μM against the NF54 drug-sensitive strain, and IC50 = 0.0246 μM against the K1 multidrug resistant strain), hERG inhibition remained an issue. Excitingly, on the other hand, new analogues with a substantially improved hERG inhibition profile (IC50 = 7.83-32.3 μM) with sub-micromolar antiplasmodial activity (NF54, IC50 = 0.151-0.922 μM) were identified. Similarly, the introduced molecular features also resulted in analogues with moderate to high solubility (60-200 μM) while also displaying sub-micromolar antiplasmodial potency (NF54, IC50 = 0.136-0.99 μM).
7-CHLORO-QUINOLIN-4-AMINE COMPOUNDS AND USES THEREOF FOR THE PREVENTION OR TREATMENT OF DISEASES INVOLVING FORMATION OF AMYLOID PLAQUES AND/OR WHERE A DYSFUNCTION OF THE APP METABOLISM OCCURS
-
Page/Page column 49, (2011/07/07)
The present invention relates to compounds having the following Formula (I) for use in the prevention and/or the treatment of diseases involving formation of amyloid plaques and/or where a dysfunction of the APP metabolism occurs.
The Effect of Fluorine Substitution on the Metabolism and Antimalarial Activity of Amodiaquine
O'Neill, Paul M.,Harrison, Anthony C.,Storr, Richard C.,Hawley, Shaun R.,Ward, Stephen A.,Park, B. Kevin
, p. 1362 - 1370 (2007/10/02)
Amodiaquine (AQ) (2) is a 4-aminoquinoline antimalarial which causes adverse side effects such as agranulocytosis and liver damage.The observed drug toxicity is believed to be related to the formation of an electrophilic metabolite, amodiaquine imine (AQQI), which can bind to cellular macro-molecules and initiate hypersensitivity reactions. 5'-Fluoroamodiaquine (5'-FAQ, 3), 5',6'-difluoroamodiaquine (5',6'-DIFAQ, 4), 2',6'-difluoroamodiaquine (2',6'-DIFAQ, 5), 2',5',6'-trifluoroamodiaquine (2',5',6'-TRIFAQ, 6) and 4'-dehydroxy-4'-fluoroamodiaquine (4'-deOH-4'-FAQ, 7) have been synthesized to assess the effect of fluorine substitution on the oxidation potential, metabolism, and in vitro antimalarial activity of amodiaquine.The oxidation potentials were measured by cyclic voltammetry, and it was observed that substitution at the 2',6'- and 4'-positions (2',6'-DIFAQ and 4'-deOH'4'-FAQ) produced analogues with significantly higher oxidation potentials than the parent drug.Fluorine substitution at the 2',6'-positions and 4'-position also produced analogues that were more resistant to bioactivation.Thus 2',6'-DIFAQ and 4'-deOH-4'-FAQ produced thioether conjugates corresponding to 2.17percent (SD: +/-0.27percent) and 0percent of the dose compared with 11.87percent (SD: +/-1.31percent) of the dose for amodiaquine.In general the fluorinated analogues had similar in vitro antimalarial activity to amodiaquine against the chloroquine resistant K1 strain of Plasmodium falciparum and the chloroquine sensitive T9-96 strain of P. falciparum with the notable exception of 2',5',6'-TRIFAQ (6).The data presented indicate that fluorine substitution at the 2',6'-positions and replacement of the 4'-hydroxyl of amodiaquine with fluorine produces analogues ( 5 and 7) that maintain antimalarial efficacy in vitro and are more resistant to oxidation and hence less likely to form toxic quinone imine metabolites.
