New heterocyclic derivatives of benzimidazole with germicidal activity--XI--Experimental validation of OSAR prediction on antibacterial and antimycotic activity of benzimidazole derivatives.

In continuation of previous studies, Authors describe the synthesis of three new derivatives of 2-(5'-nitro-2'-furyl) benzimidazole, having hydroxy, methoxy or amino group at position 5. The new compounds, synthesized as suggested by a previous chemometric study, were tested in vitro against 5 Gram + and 4 Gram- strains and the mycete C. albicans. Two derivatives (R = OH, NH2) showed a good degree of antibacterial activity, especially the 5-hydroxy derivative, but they were practically inactive against the mycete; these results are in agreement with the prediction of chemometric study.

New heterocyclic derivatives of benzimidazole with germicidal activity. X-In vivo toxicity of 5-fluoro-2-(5'-nitro-2'-furyl)-benzimidazole (F-O-NO2); preliminary observations.

The in vivo toxicity of 5-fluoro-2-(5'-nitro-2'-furyl) benzimidazole vehiculated in liposomes (L-FONO2), induced in mice by intraperitoneal injection, was evaluated. Toxicity was tested looking at the liver and kidney damage by determining some specific functional parameters (seric urea, seric GPT and urinary beta-NAG): no modifications were observed after administration of L-FONO2 for seven days.

Comparative fluorometric study of benzo(a)pyrene and aza-aromatic hydrocarbon penetration and metabolism kinetics in the skin of hairless mice.

The kinetics of penetration and metabolism of BaP, BACs, DB(a,h)ACs and DB(c,g)Cs in the skin of hairless mice was studied. The relative fluorescence intensities were measured during three hours after applying 10 nmoles of the compound to the interscapular region of the mice. By using a kinetical model which combines a non-steady diffusion of a hydrocarbon through the stratum corneum and the metabolic oxidation by epidermal cells, the rate constants for the two processes were calculated. It has been shown that B(a)AC, B(c)AC and 12-MB(a)AC penetrate into the skin and are oxidized by epidermal cells more efficiently than BaP. In contrast, alkyl-DB(a,h)ACs (except 14-MDB(a,h)AC) show a great stability in the mouse skin. The carcinogenic BaP, 7-MB(c)AC and DB(a,h)AC have average rates of elimination from the skin.

New heterocyclic derivatives of benzimidazole with germicidal activity--IX--HPLC detection of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2) in biological samples.

The HPLC technique for the isolation and quantitation of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2), previously described by the same Authors, in biological samples from mice is reported. Evidence is given that the highest biological concentration and the time needed for reaching it depend both on the dose and on the administration route. In fact, almost the same maximal biological concentration of F-O-NO2 (about 0.18 micrograms/mouse) is reached after 60 min from either 40 mg/Kg IP or 200 mg/Kg os drug administration, whereas the maximal biological concentration of F-O-NO2 (5.75 micrograms/mouse) is reached after 30 min from 120 mg/Kg IP drug administration.

Chemometric approach in a QSAR study: the antibacterial and antimicotic activities of benzofused heteroaromatic derivatives.

In order to establish quantitative relationships between the antibacterial activities of a number of thienyl- and furyl-benzimidazoles and benzoxazoles, the biological data were measured homogeneously for a selected set of 16 representative compounds of the available set of 103. The data were analyzed by the PLS method. The results of linear PLS modelling and PLS response surface modelling permitted a straightforward interpretation of the structural features relevant to the activities and the prediction of a possible optimal structure.

New heterocyclic derivatives of benzimidazole with germicidal activity--VII--2-(5'-nitro-2'-furyl or 2'-thienyl) benzimidazoles with different substituents in the 5-position.

In continuation of our previous research, the synthesis of 13 2-(5'-nitro-2'-furyl or 2'-thienyl) benzimidazoles with different substituents in 5 position is described. The new compounds were tested in vitro against 5 (Gram+) and 4 (Gram-) strains and a mycete Candida Albicans. All the derivatives showed a certain degree of antibacterial and antimycotic activity, which in some cases was fairly good.

[New heterocyclic derivatives with germicidal activity. VI. Synthesis and activity of new 2-benzoxazoyl-2'-furanes and -thiophenes variously substituted in 5 and 5' positions]. / Nuovi derivati eterociclici ad attività germicida. VI. Sintesi ed attività di nuovi 2-benzossazolil-2'-furani e-tiofeni, variamente sostituiti in 5 e 5'.

Seventeen derivatives of 2'-furyl-2-benzoxazole and three derivatives of 2'-thienyl-2-benzoxazole, having different substituents in the benzene moiety (position 5) and in the furanic or thiophenic ring (position 5'), are described, with the aim of studying antibacterial and antimycotic structure-activity relationships. None of the compounds show an important antibacterial and/or antimycotic activity, when tested against nine bacteria and Candida albicans cultures; in any case it was much lower than that previously reported for the corresponding benzimidazoles. It seems that the = NH group of the imidazole ring, which is absent in the benzoxazole derivatives, might be important for the biological activity of this class of compounds.

[New heterocyclic derivatives of benzimidazole with germicidal activity. V. Synthesis and activity of new derivatives of di-2-benzimidazolyl-2,5-furan]. / Nouveaux derives heterocycliques du benzimidazole a activite germicide. V. Synthese et activité de nouveaux di-2-benzimidazolyl-2,5-furranes asymétriques.

In continuation of the research in the field of germicidal and antimycotic agents, the synthesis of 14 new derivatives of di-2-benzimidazolyl-2,5-furan is described. These derivatives are differently substituted (R not equal to R') in the position 5 of the two benzene rings. These new compounds showed no germicidal or fungicidal activity, when tested on different cultures. New compounds are under investigation.

New heterocyclic derivatives of benzimidazole with germicidal activity. IV--In vivo anticandida activity of 5-fluoro-2-(5'-nitro-2'-furyl) benzimidazole (F-O-NO2).

We have studied the possible in vitro and in vivo antibacterial activity of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2). Our data demonstrate that F-O-NO2 is able to inhibit the in vitro growth of different mycetes and bacteria, including Candida albicans and Cryptococcus neoformans. We also tested the possible in vivo activity against Candida albicans. The results clearly show that treatment with F-O-NO2 is able to significantly augment the survival of all treated animals; in particular, when injected i.p. at the dose of 120 mg/kg, 30' or 1 hr after Candida albicans challenge, it givens a MST (Medium Survival Time) longer than 60 days. These data demonstrate that F-O-NO2 has antibacterial and antimycotic activity.

[New heterocyclic derivatives of benzimidazole with germicidal activity. III. Synthesis and activity of derivatives of (formyl-5'-furyl-2')-2-benzimidazole with different substitutions at position 5]. / Nouveaux dérivés hétérocycliques du benzimidazole à activité germicide. III--Synthèse et activité de derivés du (formyl-5'-furyl-2')-2-benzimidazole, différemment substitués en position 5.

The synthesis and germicidal properties of 28 new derivatives of furyl-2-benzimidazole are described. The compounds are substituted both in position 5 of the benzene moiety and in position 5' of the heterocycle moiety. The germicidal properties of the new molecules were tested using 9 strains of bacteria and Candida albicans. Some of them exhibited germicidal properties versus Gram + bacteria and versus Candida. Some derivatives were also tested using Mycobacterium aurum: two isonicotinoylhydrazones derivatives exhibited tubercolostatic activity comparable to that of streptomycin and not much lower than that of isoniazide.

[New heterocyclic derivatives of benzimidazole with germicidal activity. II. Mechanism of action of fluoro-5-(nitro-2'-furyl)-2-benzimidazole in B. subtilis and C. albicans]. / Nouveaux dérivés heterocycliques du benzimidazole à activité germicide. II. Etude du mecanisme d'action du fluoro-5-(nitro-2'-furyl)-2-benzimidazole sur B. subtilis et C. albicans.

Study of the microbiological activity of 5-fluoro-(2'-nitrofuryl)-2-benzimidazole F-O-NO2 (I) was continued. The substance was tested on cultures of B. subtilis and C. albicans. From the microbial strains studied, the mortality rate, the minimum inhibitory and bacterial concentrations and the cytotoxicity were determined. The action mechanism was studied using tritiated leucin, uracil and thymidine. Acute toxicity in the mouse (DL50 = 275 mg/kg) was also determined. The germicidal activity of (II), homologous N-ethyl derivative of (I), was also studied. On the basis of the results obtained, a possible mechanism of action of compound (I) is discussed.

[N1-substituted 1H-indazole-3-ethyl carboxylates and 1H-indazole-3-hydroxamic acids]. / 1H-Indazole carboxylates d'éthyle-3 N1-substitués et acides 1H-indazole hydroxamiques-3.

Sixty five new derivatives of ethyl-1H-indazole-3-carboxylate are described; they contain in N1 various aliphatic or aromatic acyl radicals. Moreover halogens or methyl groups are present as substituents at the 5 position or methyl groups at 5,6. The synthesis of seven 1H-indazole-3-hydroxamic acids, substituted at 6 and/or 5 as above, is also described. Some of the synthesized derivatives have preliminarily been tested on rats to investigate acute toxicity, possible antiarthritic effects on primary or secondary arthritis, and their action on weight gain. Some of these indazole derivatives had an antiarthritic effect at doses much lower than the toxic ones; among the compounds tested up to now, the ethyl-5-methyl-N1-p-chlorobenzoyl-1H-indazole-3-carboxylate gave the best results. Weight gain as not affected by any of the examined compounds.