Synthesis, antibacterial, and antitubercular studies of some novel isatin derivatives

The rise in clinical significance of multi drug-resistant bacterial pathogens has directed us to synthesize a novel series of isatin derivatives and characterize them by IR, NMR, mass spectral, and elemental analysis. Compounds were evaluated for their preliminary in vitro antibacterial activity against Gram-positive (Staphylococcus aureus, Staphylococcus?epidermis, Micrococcus?luteus, Bacillus?cereus) bacteria and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain by microplate alamar blue assay (MABA) method. Some synthesized compounds showed very good antibacterial and antitubercular activities.     

Synthesis and pharmacological activities of hydrazones, Schiff and Mannich bases of isatin derivatives

Schiff bases and phenyl hydrazone of isatins were prepared by reacting isatin and the appropriate aromatic primary amine/hydrazines. A new series of the corresponding N-mannich bases were synthesized by reacting them with formaldehyde and diphenylamine. The chemical structures were confirmed by means of their 1H-NMR, IR spectral data and elemental analysis. The compounds were screened for analgesic, antiinflammatory and antipyretic activity. 1-Diphenylaminomethyl-3-(1-naphthylimino)-1,3-dihydroindol-3-one (4), 3-(1-naphthylimino)-5-bromo-1,3-dihydroindol-2-one (2) and 1-diphenylaminomethyl-3-(4-methylphenylimino)-1,3-dihydroindol-3-one (7) were found to exhibit the highest analgesic, anti-inflammatory and antipyretic activity respectively. 1-Diphenylaminomethyl-3-(4-methylphenylimino)-1,3-dihydroindol-3-one (7) was found to be the most active compound of the series.     

Synthesis, antibacterial, antifungal and anti-HIV evaluation of Schiff and Mannich bases of isatin and its derivatives with triazole

Isatin (indole 2,3-dione) and its 5-chloro and 5-bromo derivatives have been reacted with 3-(4'-pyridyl)-4-amino-5-mercapto-4-(H)-1,2,4-triazole to form Schiff bases and the N-Mannich bases of these compounds were synthesised by reacting them with formaldehyde and several secondary amines. Their chemical structures have been confirmed by means of their IR, 1H-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by agar dilution method against 27 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (III B) in MT-4 cells. Among the compounds tested 1-(piperidinomethyl) 5-bromo 3-[3'-(4"-pyridyl)-5'-mercapto-4'-(H)-1',2',4'-triazol 4'-yl]imino isatin showed the most favourable antimicrobial activity.     

Biological activities of isatin and its derivatives

Isatin is an endogenous compound identified in humans that possesses a wide range of biological activities. Isatin has anxiogenic, sedative, anticonvulsant activities and acts as a potent antagonist on atrial natriuretic peptide receptors in vitro. A series of p-substituted isatin semicarbazones have shown anticonvulsant activity in MES, scPTZ and scSTY tests. Various isatin-N-Mannich bases of isatin-3-thiosemicarbazones have shown antiviral and tuberculostatic activity. Methisazone is an effective compound against variola and vaccinia viruses. The N-dimethyl and morpholino derivative of 5-methyl isatin and trimethoprim exhibited an EC50 of more than 4.3 and 17.7 mg mL(-1), respectively. Isatin (3-o-nitrophenyl) hydrazone has shown activity against Walker carcinoma-256. Various substituted indolinones showed antitubercular activity against M. tuberculosis H37Rv with MIC ranging from 10-20 microg mL(-1). Isatin derivatives of Mannich bases had fibrinolytic, muscle relaxant, antiallergic, immunosuppressant, and antithrombotic activity. Isatin showed cardioinhibitory effect on frog heart, and hypotensive, respiratory depression and antidiuretic effects.     

Synthesis, antibacterial, antifungal and anti-HIV activities of Schiff and Mannich bases derived from isatin derivatives and N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide.

Isatin, its 5-chloro and 5-bromo derivatives have been reacted with N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting them with formaldehyde and three secondary amines. Their chemical structures have been confirmed by means of IR, 1H-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by agar dilution method against 28 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (IIIB) in MT-4 cells. Among the compounds tested 1-[N,N-dimethylaminomethyl]-5-bromo isatin-3-{1'-[4"-(p-chlorophenyl) thiazol-2"-yl] thio semicarbazone} 10 showed the most favourable antimicrobial activity.     

Synthesis and antitubercular activity of novel amino acid derivatives

In this work, 17 new N-acylhydrazone derivatives of amino acids have been evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis H37Rv. The compounds 8b, 8e, 8f, 9a-d, and 10c exhibited an important minimum inhibitory concentration activity between 12.5 and 50 μg/mL, which can be compared with that of the tuberculostatic drug d-cycloserine (20 μg/mL).     

Synthesis, antibacterial, antifungal and anti-HIV evaluation of Schiff and Mannich bases of isatin derivatives with 3-amino-2-methylmercapto quinazolin-4(3H)-one

Isatin (Indole 2,3-dione), its 5-chloro and 5-bromo derivatives were added to 3-amino-2-methylmercapto quinazolin-4(3H)-one to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting with formaldehyde and several secondary amines. Their chemical structures have been confirmed by means of their IR, 1H-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by an agar dilution method against 26 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (III B) in MT-4 cells. Among the compounds tested 5-chloro-3-(3',4'-dihydro-2'-methylmercapto-4'-oxoquinazolin-3'-yl )- l-morpholino methyl imino isatin was the most active antimicrobial agent.     

含有取代吲哚满二酮-1-乙基的加替沙星衍生物的合成与抗结核作用研究

目的寻找具有优秀活性的喹诺酮类抗结核药物。方法设计合成脂溶性更大的含有取代吲哚满二酮-1-乙基的加替沙星衍生物,测定其体外抗分枝杆菌活性。结果共合成了14个新化合物,其结构经1H-NMR、MS和HRMS确证。目标物普遍具有良好的抗分枝杆菌活性(MIC为1.56~6.25μg/mL),但均弱于其母药加替沙星。其中,化合物3h对草分枝杆菌CMCC93201和耻垢分枝杆菌CMCC93202的活性分别是利福平的4倍和2倍。结论脂溶性并非决定喹诺酮类化合物抗分枝杆菌活性的唯一因素。     

Synthesis, biological activity and docking study of some new isatin Schiff base derivatives

A set of novel Schiff bases of isatin were synthesized and characterized by reaction of isatin with various aromatic or heterocyclic primary amines. Cytotoxic activities for some of the synthesized compounds were evaluated by MTT assay in three human cancer cell lines (HeLa, LS180 and Raji). Half of the tested compounds showed good cytotoxicity in HeLa cells. 3-(2-(4-nitrophenyl) hydrazono) indolin-2-one was found to be the most potent molecule among the studied isatin derivatives. Docking studies of 3-substituted indolin-2-one scaffolds on vascular endothelial growth factor receptor 2 (VEGFR-2) involved in cell proliferation and angiogenesis was performed. 3-(naphthalen-1-ylimino) indolin-2-one and 3-(2-(4-nitrophenyl) hydrazono) indolin-2-one exhibited higher docking binding energies with receptor. For 3-(2-(4-nitrophenyl) hydrazono) indolin-2-one, H-bond interaction with Cys917 residue of target active site was in common with reported crystallographic benzoimidazole derivative (PDB code: 2OH4). New key H-bonds involving Glu915, Asn921, and Arg1049 residues in VEGFR-2 active site could be detected for 3-(2-(4-nitrophenyl) hydrazono) indolin-2-one. Extended lipophilic rings containing H-bond acceptors on the 3 position of indoline scaffold seemed to be important factors in developing potent VEGFR-2 inhibitors virtually. Based on the ligand efficiency indices, some isoxazole or thiazole substituted isatin derivatives may be regarded as efficient candidates for further molecular developments of anticancer agents.     

Synthesis, antibacterial and antifungal activities of bifonazole derivatives

Two series of chlorinated benzhydryl imidazole and triazole derivatives were synthesized and tested in vitro against representative strains of potent pathogenic bacteria (Staphylococcus aureus CIP 4.83, Escherichia hirae CIP 5855, Pseudomonas aeruginosa CIP 82118, Escherichia coli CIP 53126) and fungi (Aspergillus niger IP 1431.83, Candida albicans IP 48.72, Candida krusei IP 208.52, Trichophython rubrum IP 1657.86). Most of these compounds were devoid of any antimicrobial activity, but several of them inhibited T. rubrum with MIC values in the range of 0.125 to 32 μg/mL, similar or superior to those of bifonazole and clotrimazole, used as standard controls. The replacement of the imidazole ring with a triazole moiety in these compounds led to derivatives with less antifungal activity. A preliminary SAR was undertaken on the effect of the number and the position of chlorine atoms on the distribution of negative charge on the surface of some compounds on antifungal activity.     

Synthesis and biological evaluation of andrographolide derivatives as potent anti-HIV agents

In an attempt to develop potent anti-HIV drugs, 20 andrographolide derivatives were designed, synthesized, and evaluated for their in vitro anti-HIV activity. The screening results revealed that five compounds showed potent anti-HIV activities with therapeutic indices (TI) above 10. The most promising compound 6f shows a significant TI close to 34.07, with the potency to be a new lead.     

Synthesis, antitubercular and anticancer activities of substituted furyl-quinazolin-3(4H)-ones

Some novel substituted-3-{[(1E)-(substituted-2-furyl)-methylene]amino}quinazolin-4(3H)-one (5, 6, 7) a-f were synthesized by a multi-step process. These synthesized compounds are characterized by various spectroscopic techniques and evaluated for their antitubercular and anticancer activities. Biological activity indicated that some of the title compounds are potent antitubercular and anticancer agents.     

Synthesis and anti-HIV and anti-HBV activities of 2'-fluoro-2', 3'-unsaturated L-nucleosides

The synthesis of L-nucleoside analogues containing 2'-vinylic fluoride was accomplished by direct condensation method, and their anti-HIV and anti-HBV activities were evaluated in vitro. The key intermediate 8, the sugar moiety of our target compounds, was prepared from 1,2-O-isopropylidene-L-glyceraldehyde via (R)-2-fluorobutenolide intermediate 5 in five steps. Coupling of the acetate 8 with the appropriate heterocycles (silylated uracil, thymine, N4-benzoylcytosine, N4-benzoyl-5-fluorocytosine, 6-chloropurine, and 6-chloro-2-fluoropurine) in the presence of Lewis acid afforded a series of 2'-fluorinated L-nucleoside analogues (15-18, 23-26, 36-45). The newly synthesized compounds were evaluated for their antiviral activities against HIV-1 in human peripheral blood mononuclear (PBM) cells and HBV in 2.2.15 cells. Cytosine 23, 5-fluorocytosine 25, and adenine 36 derivatives exhibited moderate to potent anti-HIV (EC50 0.51, 0.17, and 1.5 microM, respectively) and anti-HBV (EC50 0.18, 0.225, and 1.7 microM, respectively) activities without significant cytotoxicity up to 100 microM in human PBM, Vero, CEM, and HepG2 cells.     

Synthesis, antimicrobial and molluscicidal activities of new benzimidazole derivatives

A series of benzimidazole Schiff's bases, thiosemicarbazides were synthesized, azole ring systems as 1,3,4-triazole, 1,3,4-oxadiazole were prepared. 1-Methylbenzimidazole incorporated to substituted dithio-carbamate, thiophenol, diethylamine via acetamido group were synthesized. A series of pyrimidinobenzimidazoles, triazinobenz-imidazoles, and 2-(acetonylamino)-1-methylbenzimidazole were prepared. The antimicrobial and molluscicidal activities of some newly prepared compounds were carried out.