Synthesis of 2,3-dihydro-7-nitroimidazo[5,1-b]oxazoles as potential tuberculostatic agents

A series of 2,3-dihydro-7-nitroimidazo[5,1-b]oxazoles has been prepared in one-pot reaction. The proposed new method of their synthesis requires a treatment of 4,5-dinitroimidazole or 2-methyl-4,5-dinitroimidazole with oxiranes. Some of the obtained compounds have been tested in vitro for antimycobacterial activity and the spatial structure of them has been also discussed.     

Potential Antitumor Agents,VII. 5-Substituted 6-Phenylimidazo[2,1-b]thiazoles

The Vilsmeier reaction for the synthesis of the 5-formylimidazo[2,1-b]thiazoles 7–12 bearing a p-substituted phenyl ring in position 6 is reported. These compounds were used for the synthesis of the thiosemicarbazones 7a-12a , tosylhydrazones 7b-12b and 5-hydroxymethyl derivatives 13–18 which, in turn, were used as starting materials for preparing the methylcarbamic 13a-18a , ethylcarbamic 13b-18b and acetic esters 13c-18c . Preliminary results in the P-388 leukemia test are reported.     

Chromene-Based Synthetic Chalcones as Potent Antileishmanial Agents: Synthesis and Biological Activity

Two types of regioisomeric chromene-based chalcones namely, 1-(6-methoxy-2H-chromen-3-yl)-3-phenylpropen-1-ones and 3-(6-methoxy-2H-chromen-3-yl)-1-phenylpropen-1-ones were prepared and investigated for their antileishmanial activity against promastigotes form of Leishmania major. The obtained results from in vitro biological assays indicated that chloro-substituted 1-(6-methoxy-2H-chromen-3-yl)-3-phenylpropen-1-ones exhibited excellent activity against Leishmania major at non-cytotoxic concentrations.     

Synthesis and antituberculosis activity of a novel series of optically active 6-nitro-2,3-dihydroimidazo[2,1-b]oxazoles

In an effort to develop potent new antituberculosis agents that would be effective against both drug-susceptible and drug-resistant strains of Mycobacterium tuberculosis, we prepared a novel series of optically active 6-nitro-2,3-dihydroimidazo[2,1-b]oxazoles substituted at the 2-position with various phenoxymethyl groups and a methyl group and investigated the in vitro and in vivo activity of these compounds. Several of these derivatives showed potent in vitro and in vivo activity, and compound 19 (OPC-67683) in particular displayed excellent in vitro activity against both drug-susceptible and drug-resistant strains of M. tuberculosis H37Rv (MIC = 0.006 microg/mL) and dose-dependent and significant in vivo efficacy at lower oral doses than rifampicin in mouse models infected with M. tuberculosis Kurono. The synthesis and structure-activity relationships of these new compounds are presented.     

Dihydro-5,6-imidazo[2,1-b]thiazoles, dihydro-2,3-imidazo[2,1-b]benzothiazoles, analogs of levamisole

New compounds containing 5,6-dihydro imidazo[2,1-b]thiazole, 2,3,5,6-tetrahydro imidazo[2,1-b]thiazole and 2,3-dihydro imidazo[2,1-b]benzothiazole rings, substituted by heterocycles analogue to chromones, were synthesized and screened against three nematodes, in vitro. The results indicate moderate anthelmintic properties, compared to levamisole; nevertheless, some products exhibit a significant degree of activity.     

Patent Evaluation: Novel Imidazol[2,1-b]thiazole Derivatives as Anti-ulcer Agents

Summary

Novelty: Novel imidazol[2,1-b]thiazole derivatives, said to exhibit gastric acid secretion inhibiting activity, are disclosed. The compounds are potentially useful as anti-ulcer agents and possess very low toxicity.

Biology: The compounds were evaluated for anti-ulcer activity against the following models: aspirin-induced, water-immersion, stress-induced and ethanol induced, and rodent ulcer. The compounds were also evaluated for their gastric juice secretion inhibition activity and for their toxicity. A selected compound gave inhibition rates of over 40% in all ulcer models.

Chemistry: 5-(1-Hydroxybutyl)-6-methylimidazo[2,1-b]-thiazole is one of three specifically claimed compounds.

Structure:      

Fused Thiopyrano[2,3-d]thiazole Derivatives as Potential Anticancer Agents

rel-(5aR,11bR)-3,5a,6,11b-tetrahydro-2H,5H-chromeno[4′,3′:4,5]thiopyrano[2,3-d][1,3]thiazol-2-ones formed by the stereoselective Knoevenagel-hetero-Diels-Alder reaction were functionalized at the nitrogen in position 3 via reactions of alkylation, cyanoethylation, and acylation. The synthesized compounds were evaluated for their anticancer activity in NCI60 cell lines. Among the tested compounds, 3f was found to be the most active candidate with the greatest influence on leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, prostate cancer, and breast cancer subpanel cell lines with GI₅₀ values over a range of 0.37–0.67 μM.     

Potential antitumor agents. XX (1) 6-anilinoimidazo[2,1-b]thiazoles

The synthesis of 6-anilinoimidazo[2,1-b]thiazoles, related to the well-known antitumor agent amsacrine, is reported. The cytotoxic activity of the new compounds was evaluated on HeLa cells. Compound 3a, the most closely related to amsacrine, was significantly active.     

Synthesis of certain pyrimido[2,1-b]benzothiazole and benzothiazolo[2,3-b]quinazoline derivatives for in vitro antitumor and antiviral activities

Some new pyrimido[2,1-b]benzothiazole and benzothiazolo[2,3-b]quinazoline derivatives have been synthesized and tested for their antitumor and antiviral activities. Among therm, compounds 5c and 8d exhibited a broad spectrum antitumor activity with full panel (MG-MID) median growth inhibition (GI50) of 11.0 and 11.9 mumol/l, respectively. On the other hand, compounds 5c and 5d showed potential activity against Herpes simplex type-1(HSV-1) with 61 and 50% reduction in the viral plaques, respectively. The detailed synthesis, spectroscopic and biological data are reported.     

Synthesis and antimicrobial activities of novel naphtho[2,1-b]pyran, pyrano[2,3-d]pyrimidine and pyrano[3,2-e][1,2,4]triazolo[2,3-c]-pyrimidine derivatives

The synthesis of new naphtho[1',2':5,6]pyrano[2,3-d]pyrimidines and related heterocycles has been reported. The key intermediate 3-amino-8-bromo-1-(p-methoxyphenyl)-1H-naphtho[2,1-b] pyran-2-carbonitrile (3c) was obtained in one pot synthesis by treating alpha-cyanocinnamonitrile (1c) with 6-bromo-2-naphthol (2). Antimicrobial activity was shown for some of the synthesized compounds.     

Potential antitumor agents. 37. Synthesis and antitumor activity of guanylhydrazones from imidazo[2,1-b]thiazoles and from the new heterocyclic system thiazolo[2',3':2,3]imidazo[4,5-c]quinoline

This paper reports synthesis and antitumor activity of new guanylhydrazones from imidazo[2,1-b]thiazoles and from the new heterocyclic system thiazolo[2',3':2,3]imidazo[4,5-c]quinoline. The compounds were tested as potential antitumor agents at the National Cancer Institute. The effect of the guanylhydrazone of 2-chloro-6-(2,5-dimethoxy-4-nitrophenyl)imidazo[2,1-b]thiazole-5-carbaldehyde (41) was investigated, and it was found to be an inhibitor of Complex III of the mitochondrial respiratory chain and is able to induce apoptosis in the cell lines HT29 and HL60.     

6‐Substituted Indolo[1,2‐c]quinazolines as New Antimicrobial Agents

A series of 2‐o‐arylidineaminophenylindoles and their cyclic derivatives (indolo[1,2‐c]quinazolines) were synthesized. The reactions occurred under relatively mild conditions and afforded the desired product in good yields. Molecular structures of the synthesized compounds were confirmed by IR, ¹H‐NMR, ¹³C‐NMR, MS spectra, and elemental analyses. Furthermore, all the final products were screened for in‐vitro antibacterial activity against three Gram‐positive and three Gram‐negative bacteria and also tested for their inhibitory action against three strains of fungi. Compound IIc showed potent activity against all the bacterial (except S. typhimurium) and fungal strains. Especially, compounds IIi and IIj which have isoquinolyl and pyridyl substituents displayed potent antibacterial as well as antifungal activities compared to those of the respective standard drugs Ampicillin and Ketoconazole.     

吡啶并[2,3-b]吡嗪类FGFR抑制剂的设计、合成及抗胃癌活性研究

目的设计并合成一系列吡啶并[2,3-b]吡嗪类成纤维细胞生长因子受体(FGFR)抑制剂,同时对其抗胃癌活性进行初步评价。方法以5-溴吡啶-2-胺为起始原料,经9步反应合成了13个未见报道的化合物,并通过MTT法评价其抗胃癌活性。结果与结论目标化合物的结构经NMR和HRMS确证,其中多个化合物对胃癌SNU-16细胞系具有良好的抑制活性,具有进行更深入的构效研究价值,有望成为一种潜在的新增FGFR抑制剂。     

1,2-Dihydro-3,1-benzoxazin-4-one and 4H-1,2-dihydro-pyrido-[2,3-d]- [1,3]-oxazin-4-one derivatives as potential prodrugs. Part I: Synthesis.

1-Mono- and previously unknown 1,2-disubstituted 1,2-dihydro-3,1-benzoxazin-4-ones 7 and 9, potential prodrugs of flufenamic acid (6) and mefenamic acid (8), and 4H-1,2-dihydro-pyrido-[2,3-d]-[1,3]-oxazin-4-ones 11, potential prodrugs of niflumic acid (10), were prepared; the structures of all new compounds wereconfirmed by spectroscopic methods.     

1,2-Dihydro-3,1-benzoxazin-4-one and 4-H-1,2-dihydro-pyrido-[2,3-d]-[1,3]-oxazin-4-one derivatives as potential prodrugs. Part II: Hydrolysis.

The kinetics of the spontaneous hydrolysis of the potential prodrugs 1a-1f, 2a-2g, and 3a-3e in methanol-buffer mixtures (3:7) at various pH-values was studied and a simple analytical uv-spectroscopic method was developed. The results show that most of the new potential prodrugs were very quickly reconverted to their parent drugs under these conditions. All of the potential prodrugs are very sensitive between pH 4.0 and 8.0, with half lives less than 50 min at 20 degrees C, except for compounds 1f, 2f, and 3d. Compounds 1b and 1c are so sensitive that they reconverted to their parent drug during the mixing of the stock solution and the buffer-methanol-mixture.     

Substituted Xanthones as Antimycobacterial Agents,Part 2: Antimycobacterial Activity

A series of substituted xanthones was tested for their activity against four mycobacterial strains (Mycobacterium tuberculosis, M. avium, M. lufu, M. smegmatis) by determination of the minimum inhibitory concentrations (MIC values). For the most active compounds, supplementary characterisation was performed by bacterial growth kinetics, which allows a more precise interpretation of their antimycobacterial effects. From the test set, 1-methyl-2,4,7-trinitroxanthone ( 8a ) showed the highest antimycobacterial activity with a MIC value of 3 μg/mL against M. tuberculosis, which is comparable to the effect of well known drugs used in the treatment of tuberculosis. For all other compounds, the MIC values could not be determined, due to the comparatively low activity and to the poor solubility of the compounds, respectively. The semiquantitative evaluation of activity against the different strains of mycobacteria resulted in a classification into three activity classes, which will be used as dependent parameter in QSAR investigations, to be published in Part 3 of this series.     

Condensed Thienopyrimidine Derivatives. Part 20: Synthesis and Neurotropic Activity of a Series of New Pyrano[4',3':4,5]Thieno[3,2-e]Imidazolidino-[2,1-b]Pyrimidines

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