A review on diverse heterocyclic compounds as the privileged scaffolds in antimalarial drug discovery.

The upward extend of malaria collectively with the emergence of resistance against predictable drugs has put enormous pressure on public health systems to introduce new malaria treatments. Heterocycles play an important role in the design and discovery of new malaria active compounds. Heterocyclic compounds have attracted significant attention for malaria treatment because of simplicity of parallelization and the examining power with regard to chemical space. Introduction of a variety of heterocyclic compounds have enabled to maintain the high levels of antimalarial potency observed for other more lipophilic analogues whilst improving the solubility and the oral bioavailability in pre-clinical species. In this review, we present an overview of recent literature to provide imminent into the applications of different heterocyclic scaffolds in fighting against malaria.

Ultrasound-assisted one-pot four-component synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole scaffold and their biological broadcast.

An alternative and environmentally caring way for the synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole nucleus is reported by one-pot four-component cyclocondensation reaction of substituted 5-(1H-imidazol/4-methyl-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (3a-b), malononitrile (4), ammonium acetate (5) and aromatic (6a-f)/heterocyclic methyl ketones (7a-d) under ultrasonic irradiation. The newly synthesized compounds were evaluated for their in vitro antibacterial activity against a panel of pathogenic stains of bacteria and fungi, in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv stain and in vitro antioxidant activity by ferric-reducing antioxidant power method. Compounds 8e, 8h, 8l, 9c, 9g and 9h exhibited excellent antibacterial activity and compounds 3a, 8k, 9a and 9bshowed moderate antituberculosis activity as compared with the first line drugs. Majority of the compounds showed excellent antioxidant activity. This approaches claimed to be an environment friendly protocol as it afforded numerous advantages i.e. excellent yields, cleaner reaction profile and shorter reaction time.

Synthesis, characterization and pharmacological screening of some novel 5-imidazopyrazole incorporated polyhydroquinoline derivatives.

A new category of polyhydroquinoline derivatives 8a-t were synthesized in moderate to good yield (64-85%) by one-pot three-component cyclocondensation reaction of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 3 with various enaminones 6a-h and different active methylene compounds (malononitrile 7a, ethylcaynoacetate 7b and caynoacetamide 7c) in absolute ethanol. The newly synthesized compounds were evaluated for their in vitro antimalarial activity against Plasmodium falciparum, in vitro antibacterial activity against a panel of pathogenic strains of bacteria and fungi and also for their antitubercular activity against Mycobacterium tuberculosis H37Rv strain. Two of them (8n, 8t) exhibited excellent antimalarial activity. Some of them exhibited excellent antibacterial activity and moderate antituberculosis activity compared with the first line drugs.

Catalytic regioselective synthesis of pyrazole based pyrido[2,3-d]pyrimidine-diones and their biological evaluation.

A new type of biopolymer-based heterogeneous catalyst, cellulose supported acidic ionic liquid (Cell-IL), which was developed earlier in our lab, has been found to be very effective for the regioselective synthesis of pyrazole based pyrido[2,3-d]pyrimidine-diones. Its regioselectivity was confirmed by (1)H NMR spectroscopy. All the newly synthesized compounds were characterized by LC-MS, (1)H NMR, (13)C NMR, IR spectroscopy and elemental analysis. The newly synthesized compounds were evaluated for their in vitro antimalarial activity against Plasmodium falciparum, in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv strain and also for their antibacterial activity against a panel of pathogenic strains of bacteria and fungi. Some of them exhibited excellent activity when compared with first line drugs.