ABSTRACT
Grimmel's method was optimized as well as modified leading to the cyclization and incorporation of alanine linked sulphonamide in 4-quinazolin-(3H)-ones. Further, the generation of heterocyclic motif at position-3 of 4-quinazolinones was explored by synthesis of imines, which unfortunately led to an isomeric mixture of stereoisomers. The hurdle of diastereomers encountered on the path was eminently rectified by development of new rapid and reproducible methodology involving the use of imidazolium based ionic liquid as solvents as well as catalyst for cyclization as well as synthesis of imines in situ at position-3 leading to procurement of single E-isomer as the target hybrid heterocyclic molecules. The purity and presence of single isomer was also confirmed by HPLC and spectroscopic techniques. Further, the synthesized sulphonamide linked 4-quinazolin-(3H)-ones hybrids were screened for their antimalarial potency rendering potent entities (4b, 4c, 4â¯l, 4â¯t and 4u). The active hybrids were progressively screened for enzyme inhibitory efficacy against presumed receptor Pf-DHFR and h-DHFR computationally as well as in vitro, proving their potency as dihydrofolate reductase inhibitors. The ADME properties of these active molecules were also predicted to enhance the knowhow of the oral bioavailability, indicating good bioavailability of the active entities.
Subject(s)
Alanine/pharmacology , Antimalarials/pharmacology , Enzyme Inhibitors/pharmacology , Plasmodium falciparum/drug effects , Quinazolinones/pharmacology , Tetrahydrofolate Dehydrogenase/metabolism , Alanine/chemistry , Animals , Antimalarials/chemical synthesis , Antimalarials/chemistry , Caco-2 Cells , Catalysis , Chlorocebus aethiops , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Folic Acid/metabolism , Humans , Ionic Liquids/chemistry , Models, Molecular , Molecular Structure , Parasitic Sensitivity Tests , Quinazolinones/chemical synthesis , Quinazolinones/chemistry , Stereoisomerism , Structure-Activity Relationship , Vero CellsABSTRACT
An optimization of a modified Grimmel's method for N-heterocyclization of Leucine linked sulphonamide leading to 2,3-disustituted-4-quinazolin-(3H)-ones was accomplished. Further, nineteen hybrid quinazolinone motifs (5a-5s) were synthesized by N-heterocyclization reaction under microwave irradiation using TEAA (IL) as green solvent as well as catalyst. The in vitro screening of the hybrid entities against the plasmodium species P. falciparum yielded five antimalarial potent molecules 5g, 5l, 5m, 5n &5p owing comparable activity to the reference drugs. The active scaffolds were further evaluated for enzyme inhibition efficacy against alleged receptor Pf-DHFR computationally as well as in vitro, proving their candidature as lead dihydrofolate reductase inhibitors. The prediction of the ADMET properties of the potent molecules also indicated their good oral bioavailability.
Subject(s)
Antimalarials/chemical synthesis , Folic Acid Antagonists/chemical synthesis , Quinazolines/pharmacology , Amino Acids/chemistry , Antimalarials/pharmacology , Biological Availability , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Folic Acid Antagonists/pharmacology , Plasmodium falciparum/drug effects , Quinazolines/chemical synthesis , Sulfonamides/chemistry , Tetrahydrofolate DehydrogenaseABSTRACT
Sulfonamide substituted 8-hydroxyquinoline derivatives were prepared using a microwave synthesizer. The interaction of sulfonamide substituted 8-hydroxyquinoline derivatives and their transition metal complexes with Plasmid (pUC 19) DNA and Calf Thymus DNA were investigated by UV spectroscopic studies and gel electrophoresis measurements. The interaction between ligand/metal complexes and DNA was carried out by increasing the concentration of DNA from 0 to 12 µl in UV spectroscopic study, while the concentration of DNA in gel electrophoresis remained constant at 10 µl. These studies supported the fact that, the complex binds to DNA by intercalation via ligand into the base pairs of DNA. The relative binding efficacy of the complexes to DNA was much higher than the binding efficacy of ligands, especially the complex of Cu-AHQMBSH had the highest binding ability to DNA. The mobility of the bands decreased as the concentration of the complex was increased, indicating that there was increase in the interaction between the metal ion and DNA. Complexes of AHQMBSH were excellent for DNA binding as compared to HQMABS.
ABSTRACT
A novel 4-[(8-hydroxyquinolin-5-yl)methyl]aminobenzenesulfonamide (HQMABS) was synthesized by optimized reaction of 4-aminobenzenesulfonamide with 5-chloromethyl-8-hydroxyquinoline hydrochloride (CMHQ). Various oxinates of HQMABS were also prepared using Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) metal salts. All compounds were analyzed by physicochemical, thermogravimetric and spectroscopic techniques. Antimicrobial activity was carried out using agar-plate method against various strains of bacteria (Staphylococcus aureus, Bacillus subtillis, Pseudomonas aerugionsa, and Escherichia coli) and spores of fungi (Aspergillus niger and Aspergillus flavous). The results showed significantly higher antimicrobial activity of HQMABS compared to the parent 8-hydroxyquinoline and sulfonamide, while oxinates of HQMABS showed milder activity.
