Synthesis,in-vitroMicrobial and Cytotoxic Studies of New Benzimidazole Derivatives

Cu-catalyzed convenient synthesis of 2-trifluoromethyl benzimidazoles via cyclization of o-phenylenediamines with hexafluoroacetylacetone

An efficient and convenient method for the synthesis of 2-trifluoromethyl benzimidazoles is described in this paper. The cyclization reaction of various o-phenylenediamines with hexafluoroacetylacetone proceeded smoothly in the presence of Cu2O as the catalyst to produce 2-trifluoromethyl benzimidazoles in satisfactory to excellent yields (up to >99% yield). The CF3 source, hexafluoroacetylacetone, acted not only as cyclization partner, but also acted as a ligand for the Cu catalyst. Various synthetically useful functional groups, such as halogen atoms, cyano, and methoxycarbonyl groups, remained intact during the cyclization reactions. The reaction mechanism was thoroughly investigated and was determined to involve a seven-membered cyclic diimine intermediate.

Design, Synthesis and Evaluation of Antiproliferative Activity of New Benzimidazolehydrazones

The synthesis and antiproliferative activity of new benzimidazole derivatives bearing an hydrazone mojety at the 2-position is described. The new N′-(4-arylidene)-1H-benzo[d]imidazole-2-carbohydrazides were evaluated for their cytostatic activity toward the murine leukemia (L1210), human T-cell leukemia (CEM), human cervix carcinoma (HeLa) and human pancreas carcinoma cells (Mia Paca-2). A preliminary structure-activity relationship could be defined. Some of the compounds possess encouraging and consistent antiproliferative activity, having IC₅₀ values in the low micromolar range.

An Efficient and Facile Synthesis of 1,2,4-Aryl Triazoles and 4-Thiazolidinones Bearing 6-Fluorochroman Nucleus

A new generation of chroman bearing heterocyclic five membered ring such as 1,2,4-triazoles and thiazolidinones was designed and synthesized. New chroman based nucleus 5-(6-fluorochroman-2-yl)-4-aryl-4H-1,2,4-triazole-3-thiol and 6-fluorochroman-N-(4-oxo-2-arylthiazolidinin-3-yl) chroman-2-carboxamides were synthesized. Aryl triazole compounds 4a–4j were synthesized from 6-fluorochroman-2-carbohydrazide 2 on reaction with base in methanol and CS₂ followed by reaction with substituted aniline. Thiazolidinone compounds 5a–5j were synthesized from 6-fluorochroman-2-carbohydrazide 2 on reaction with substituted aryl aldehyde and thioglycolic acid.

Synthesis, in-vitro antimicrobial and cytotoxic studies of novel azetidinone derivatives

Developing novel antimicrobial drugs is increasingly important in the modern pharmaceutical industry. A series of novel 3-chloro-4-[4-(2-oxo-2H-chromen-4-ylmethoxy)phenyl]-1-phenylazetidin-2-ones 5a-o have been synthesized from 4-bromomethylcoumarins 1a-e and 4-aryliminomethyl-phenols 3a-c. These compounds were screened for their in-vitro antibacterial activity against two Gram-positive (Staphylococcus aureus and Vancomycin resistant enteroccoccus) and two Gram-negative (Escherichia coli and Shigella dysentery) bacterial strains and antifungal activity against Aspergillus fumigatus, Candida albicans, and Penicillium. Results revealed that compounds 5c, 5f, 5h, 5j, and 5m showed excellent activity against a panel of microorganisms. The brine-shrimp bioassay was also carried out to study their in-vitro cytotoxic properties and two compounds, 5h and 5m, possessing LD(50) = 7.154x10(-4 )M and 5.782x10(-4) M, respectively, displayed potent cytotoxic activity against Artemia salina. The presence of a chlorine group in the coumarin moiety, its effect on their antibacterial, antifungal, and cytotoxic activities is discussed. All newly synthesized compounds were characterized by elemental analysis, IR, (1)H-NMR,( 13)C-NMR, and MS.

Analgesic, anti-pyretic and DNA cleavage studies of novel pyrimidine derivatives of coumarin moiety

A novel series of 4-[4-(6-phenyl-pyrimidin-4-yl)-phenoxymethyl]-chromen-2-ones [5-7(a-e)] were synthesized from various 4-bromomethyl coumarins 1(a-e). The synthesized compounds were screened for in-vivo analgesic and anti-pyretic activities at a dose of 25 and 100 mg/kg body weight (b.w), respectively. Among them, compounds 5(d), 6(c) and 7(d) exhibited significant analgesic activity comparable with standard drug analgin using Tail-flick model. Compounds 5(a) and 7(a-d) showed significant anti-pyretic activities comparable with standard drug aspirin using yeast-induced pyrexia model. DNA cleavage study by agarose gel electrophoresis method was also studied. Qualitative SAR studies indicate that, compounds with amino group at 2-position of pyrimidine ring enhances analgesic and anti-pyretic activities and compounds with hydroxyl and thio group at 2-position of pyrimidine ring increase DNA cleavage activities.

In-vivo analgesic and anti-inflammatory activities of newly synthesized benzimidazole derivatives

A series of 2-methylaminobenzimidazole derivatives (1-11) were synthesized by the reaction of 2-(chloromethyl)-1H-benzimidazole derivatives with primary aromatic amines. All these compounds were characterized by IR, 1H NMR, 13C NMR, GC-MS and elemental analysis. The newly synthesized compounds were screened for analgesic and anti-inflammatory activities on acetic acid induced writhing in mice and carrageenan induced paw oedema in rats. Compounds (7) and (2) showed a potent analgesic (89% at 100 mg/kg b.w) and anti-inflammatory (100% at 100 mg/kg b.w) activities compared with standard drug Nimesulide (100% at 50 mg/kg b.w) respectively. The other compounds showed good analgesic and anti-inflammatory activities.

Derivatives of benzimidazole pharmacophore: synthesis, anticonvulsant, antidiabetic and DNA cleavage studies

In seeking broad spectrum pharmacological activities of benzimidazole derivatives, a group of 4-thiazolidinones 5(a-j) and 1,3,4-oxadiazoles 6(a-j) containing 2-mercapto benzimidazole moiety were synthesized and screened for in vivo anticonvulsant activity by Maximal Electroshock (MES) model and antidiabetic activity using Oral Glucose Tolerance Test (OGTT). Compounds (5c), (5d), (5g) and (5i) exhibited potent anticonvulsant results and (6c), (6d), (6h) and (6i) showed excellent antidiabetic activities and also pharmacophore derived from active molecules suggested that presence of -OH group was a common feature in all active compounds. In DNA cleavage studies, compound (5d) cleaved DNA completely as no trace of DNA was found. On the other hand, a sharp streak was found for compounds (5c), (6a) and (6d).