Pyrazolines are well known and important nitrogen containing 5-membered heterocyclic compounds and various methods have been worked out for their synthesis. Numerous pyrazoline derivatives have been found to possess considerable biological activities, which stimulated the research activity in this field. They have several prominent effects, such as antimicrobial, antimycobacterial, antifungal, antiamoebic, anti-inflammatory, analgesic, antidepressant and anticancer activities. They also possess some potent receptor selective biological activity like Nitric oxide synthase (NOS) inhibitor and Cannabinoid CB1 receptor antagonists activity. 4,5-dihydro-1H- pyrazolines seem to be the most frequently studied pyrazoline type compounds. As a result, a large number of such pyrazolines using different synthetic methods for their preparation have been described in the chemistry literature. The present review provides an insight view to pyrazolines synthesis and its biological activities along with the compilation of recent patents on pyrazolines.

SummarySeveral five membered ring systems, e.g., triazole, oxadiazole dithiazole and thiadiazole with three heteroatoms at symmetrical or asymmetrical positions have been studied because of their interesting pharmacological properties. In this article our emphasis is on synthetic development and pharmacological activity of the triazole moiety which exhibit a broad spectrum of pharmacological activity such as antifungal, antibacterial, anti-inflammatory and anticancer etc. Triazoles have increased our ability to treat many fungal infections, for example, candidiasis, cryptococcal meningitis, aspergillosis etc. However, mortality due to these infections even with antifungal therapy is still unacceptably high. Therefore, the development of new antifungal agents targeting specific fungal structures or functions is being actively pursued. Rapid developments in molecular mycology have led to a concentrated search for more target antifungals. Although we are entering a new era of antifungal therapy in which we will continue to be challenged by systemic fungal diseases, the options for treatment will have greatly expanded.

Antimalarial drugs constitute a major part of antiprotozoal drugs and have been in practice for a long time. Antimalarial agents generally belong to the class of quinoline which acts by interfering with heme metabolism. The recent increase in development of chloroquine-resistant strains of Plasmodium falciparum and failure of vaccination program against malaria have fuelled the drug discovery program against this old and widespread disease. Quinoline and its related derivative comprise a class of heterocycles, which has been exploited immensely than any other nucleus for the development of potent antimalarial agents. Various chemical modifications of quinoline have been attempted to achieve analogs with potent antimalarial properties against sensitive as well as resistant strains of Plasmodium sp., together with minimal potential undesirable side effects. This review outlines essentially some of the recent chemical modifications undertaken for the development of potent antimalarial agents based on quinoline.

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PURPOSE:In view of the potential pharmacophoric nature of imidazole nucleus, two series of imidazole derivatives, 2,4-disubstituted-1 H-imidazoles (2a-m) and 1,2,4-trisubstituted-1 H-imidazoles (3a-m), were synthesized with an aim of obtaining dual acting compounds i.e., anti-inflammatory and antifungal agents.MATERIALS AND METHODS:The title compounds were synthesized from 4-methoxyphenyl glyoxal (1) following multistep synthesis, and their structures were established on the basis of modern analytical techniques (IR, NMR and MS). The synthesized imidazoles were tested for their in vivo anti-inflammatory activity. In addition to that, some compounds were also evaluated for their analgesic and ulcerogenic effects. The compounds were also evaluated for their in vitro antifungal activity.RESULTS:Di- and tri-substituted imidazole derivatives (2a-m and 3a-m) were successfully synthesized. In in vivo anti-inflammatory test, six compounds (2 h, 2 l, 3 g, 3 h, 3 l and 3 m) exhibited good anti-inflammatory activity (49.58 to 58.02% inhibition) with minimal GI irritation (severity index; 0.17 to 0.34). These compounds were also tested for their analgesic activity and showed appreciable protection (40.53 to 49.60% protection) against saline-induced writhing test. Indomethacin was used as standard drug for comparison. In antifungal test, two compounds (3 h and 3 l) displayed appreciable antifungal activity (MIC; 12.5 μg mL-1) against the fungal strains tested.CONCLUSION:Two compounds, 2-(4-nitrophenyl)-4-(4-methoxyphenyl)-1-phenyl-1H-imidazole (3 h) and 2,4-di-(4-methoxyphenyl)-1-phenyl-1H-imidazole (3 l), emerged as lead compounds having dual biological activities; good anti-inflammatory as well as antifungal effect with lesser GI irritation.

A series of secondary amines (4-19) containing 2-chloroquinoline as lipophilic domain have been synthesized based on the structural requirements essential for allylamine/benzylamine antimycotics by nucleophilic substitution reaction of 3-chloromethyl-2-chloroquinoline 3 with various aliphatic and aromatic amines in absolute ethanol in the presence of triethylamine. Some N-methyl derivatives (20-25) were also synthesized by N-methylation using (CH 3 ) 2 SO 4 /NaH. The structures of newly synthesized compounds were established by the combined use of IR, 1 H-NMR, 13 C-NMR, and Mass spectra. Compounds 4-25 were screened in vitro at conc. of 200 g/ml for their antifungal activity against Aspergillus niger MTCC 281, Aspergillus flavus MTCC 277, Monascus purpureus MTCC 369, and Penicillium citrinum NCIM 768 by cupplate method using Terbinafine as a references drug. Among the secondary amines, compounds 4, 5, 8, 10, 14, and 16 exhibited potential antifungal activity and their corresponding N-methyl (20-25) derivatives also showed further increase in antifungal activity against fungal strain Aspergillus niger MTCC 281, Aspergillus flavus MTCC 277. Compounds 3-chloro-N-[(2-chloroquinolin-3-yl)methyl]-4-fluoro-N-methylaniline (24) and 3,4-dichloro-N-[(2-chloroquinolin-3-yl)methyl]-N-methylaniline (25) were the most potent derivatives of the series.

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