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Biomedical subjects

K Waisser

Publications and source records attributed to K Waisser.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Antimicrobial salicylanilides and 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-diones].

Salicylanilides and 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-diones are strong antimycobacterial substances which can be considered to be potential antituberculotics. In order to be able to verify the prognostics of the relationships between the structure and antimycobacterial activity, the series of previously evaluated substances was extended to include 4'-ethoxycarbonylsalicylanilide, 4'-trifluoromethylsalicylanilide, 4'-cyanidosalicylanilide, 4'-thiocarbamoylsalicylanilide, 3-(4-ethoxycarbonylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dione, 3-(4-trifluoromethylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dione, and 3-(4-cyanidophenyl)-2H-1,3-benzoxazine-2,4-(3H)-dione. The substances were evaluated against Mycobacterium tuberculosis, M. kansasii, and M. avium. In harmony with the previous study (see ref. 1), antimycobacterial activity increased with increasing lipophilicity and electron-acceptor properties of substituents. As the values of regression coefficients were not substantially changed after the complementation of the group, the present authors consider the problem under study to be solved.

Anti-Bacterial Agents↗
PubMed2001

[Advances in the development of new antitubercular agents from a group of ortho-condensed heterocyclic compounds. Part 1. Compounds containing one heteroatom per six-membered ring].

Tuberculosis and other mycobacterial diseases are considered to be one of the most important problems of contemporary health service. Since 1985 and particularly in the 1990s and at present the search for new structures of antimycobacterial agents have ranked among the foremost areas of chemotherapeutic research. The present review paper is already the 16th communication in a group of review papers about the development of new antituberculotics in recent 15 years. The literature search is based on the journal Chemical Abstracts, Current Awareness in Biomedicine, part Mycobacteria, and original papers. Current Awareness in Biomedicine is, however, a very imperfect literature search source, recording only a fraction of communications. Though none of the ortho-condensed heterocyclic compounds has been introduced into practice, the in vitro evaluated activities of some of them equalled those of routine antituberculotics. Polycyclic systems make it possible to widely model the structures, and therefore the present review paper can inspire a search for new structures of antimycobacterial agents.

Antitubercular Agents↗
PubMed2001

[Advances in the development of new antitubercular agents from a group of orthocondensed heterocyclic compounds. Part 2. Substances containing more nitrogen atoms in the 6-membered ring].

Tuberculosis and other mycobacterial diseases are considered to be one of the most important problems of contemporary health service. Since 1985 and particularly in the 1990s and at present the search for new structures of antimycobacterial agents have ranked among the foremost areas of chemotherapeutic research. The present review paper is already the 17th communication in a group of review papers about the development of new antituberculotics, the sixth about the development in recent 15 years and the second communication devoted in this series to ortho-condensed heterocyclic compounds. The classification of ortho-condensed compounds is based on six-membered heterocyclic substructural fragments. The literature search is based on the journal Chemical Abstracts, Current Awareness in Biomedicine, part Mycobacteria, and original papers. Current Awareness in Biomedicine is, however, a very imperfect literature search source, recording only a fraction of communications.

Antitubercular Agents↗
PubMed2001

[Advances in the development of new antitubercular agents from orthocondensed heterocyclic compounds. Part 3. Substances containing several types of heteroatoms in the six-membered ring].

Tuberculosis and other mycobacterial diseases are considered to be one of the most important problems of contemporary health service. Since 1985 and particularly in the 1990s and at present the search for new structures of antimycobacterial agents have ranked among the foremost areas of chemotherapeutic research. The present review paper is already the 18th communication in a group of review papers about substances with antituberculotic effects, and the third, final, communication devoted in this series about the development of new antimycobacterial agents to ortho-condensed heterocyclic compounds in recent 15 years. The classification of ortho-condensed compounds is based on six-membered heterocyclic substructural fragments and the present study deals with the substructural fragments containing a greater number of different heteroatoms. The literature search is based on the journal Chemical Abstracts, Current Awareness in Biomedicine, part Mycobacteria, and original papers. Current Awareness in Biomedicine is, however, a very imperfect literature search source, recording only a fraction of communications. Review papers about five-membered heterocyclic antituberculotic ortho-condensed compounds was published in the present journal in 1999.

Antitubercular Agents↗
PubMed2000

Combination of molecular modeling and quantitative structure-activity relationship analysis in the study of antimycobacterial activity of pyridine derivatives.

A set of 4-benzylsulfanyl derivatives of pyridine-2-carbonitriles and pyridine-2-carbothioamides, previously tested for their antimycobacterial activity, were analysed by quantitative structure-activity relationship (QSAR) techniques, using some physicochemical and quantum-chemical parameters. The resulting QSAR revealed that the activity increases with electron withdrawing substituents in the benzyl moiety of studied compounds. HOMO orbitals can play an important role in the description of the mechanism of interactions at the molecular level. Additionally, the results of multiple linear regression indicate the differences between Mycobacterium tuberculosis and M. avium. The hydrophobicity of studied compounds is important for activity against M. avium.

Anti-Infective Agents↗
PubMed2000

3-Phenyl-5-methyl-2H,5H-furan-2-ones: tuning antifungal activity by varying substituents on the phenyl ring.

A series of racemic 3-phenyl-5-methyl-2H,5H-furan-2-ones related to a natural product, (-)incrustoporine, was synthesized, and their antifungal activity evaluated. The key structural feature, furanone ring, was closed via H2SO4-mediated cyclization of 2-phenylpent-4-enoic acids. The compounds displayed antifungal activity, especially against filamentous fungi. Expressed as the minimum inhibition concentration (MIC) in micromol/L, the activity of the most promising derivative against Absidia corymbifera matched that of ketoconazole (31.25 micromol/L). In terms of microg/mL, the substance was more active (7.6 microg/mL) than this standard antifungal drug (16.6 microg/mL).

4-Butyrolactone↗
PubMed2000

Antifungal properties of substituted 1-phenyl-5-mercaptotetrazoles and their oxidation product, 5-bis-(1-phenyltetrazolyl)disulfide.

The antifungal effect of substituted 1-phenyl-5-mercaptotetrazoles was tested with Candida tropicalis, C. pseudotropicalis, C. mogii, Trichosporon cutaneum, Cryptococcus albidus and S. cerevisiae. Candida strains exhibited the lowest sensitivity to the compounds; the most sensitive was S. cerevisiae. The MIC values ranged from 40 to > 1000 mg/mL. The antifungal effect of halogenated compounds decreased in the series of bromo > chloro > fluoro derivatives. The electrochemical oxidation of substituted 1-phenyl-5-mercaptotetrazole derivatives in an acetonitrile medium was studied as a model for the enzymic oxidation of the substance, including study of the effect of water, perchloric and trifluoromethanesulfuric acids on E1/2 and I1. 5-Bis-(1-phenyltetrazolyl)disulfide, the compound with no antifungal effect, has been identified as the main oxidation product of 1-phenyl-5-mercaptotetrazole.

Acetonitriles↗
PubMed2000

[Antitubercular derivatives of quinazoline].

The study is a review paper about the development of antituberculous substances in the group of quinazoline derivatives. Most antituberculous compounds under study contain the pertinent pharmacophores in the functional groups and their antituberculous activity cannot be considered to be specific for quinazolines. Nevertheless, several groups of antituberculously effective quinazoline derivatives were found which do not contain the known pharmacophores of antituberculous activity. The substances are, on the rule, of medium activity, but the activity of some of them, evaluated in vitro, approaches that of commonly used antituberculous agents. They can thus initiate new research in this direction. The present paper is already the 12th communication in a series of review papers about substances with antituberculous activity.

Antitubercular Agents↗
PubMed2000

[Advances in the development of new antitubercular agents from pyridine derivatives].

Tuberculosis and other mycobacterial diseases are considered to be one of the major health problems at present. Since 1985, and in particular in the 1990s, a search for new structures of antimycobacterial substances has been one of the priorities of chemotherapeutic research. Pyridine derivatives have always attracted the interest of research laboratories searching for new chemotherapeutic agents against tuberculosis. The present review paper, based on the journal Chemical Abstracts and original papers, surveys these attempts in recent fifteen years.

Antitubercular Agents↗
PubMed2000

[Advances in the development of new antitubercular agents from a group of monocyclic 6-membered heterocyclic compounds with a greater number of nitrogen atoms].

Tuberculosis and other mycobacterial diseases are considered to be one of the major health problems at present. Since 1985, and in particular in the 1990s, a search for new structures of antimycobacterial substances has been one of the priorities of chemotherapeutic research. Pyrazine derivatives have always attracted the interest of research laboratories searching for new chemotherapeutic agents against tuberculosis. The present review paper, based on the journal Chemical Abstracts and original papers, surveys the attempts of the laboratories searching for new antituberculotic agents in the region of six-membered heterocyclic pyrimidine, pyrazine, and triazines compounds in recent fifteen years.

Antitubercular Agents↗
PubMed1999

New pyridine derivatives as potential antimicrobial agents.

A set of pyridine derivatives bearing a substituted alkylthio chain or a piperidyl ring in position 2 or 4 were synthesized, and their antimycobacterial and antifugal activities were evaluated. Chemical structures were confirmed by IR and NMR data, and by elemental analysis. Minimum inhibitory concentrations (MIC) were used for the evaluation of microbiological activity in vitro. The compounds were moderately active against both Mycobacterium tuberculosis and nontuberculous mycobacteria. The most active compound was 2-cyanomethylthiopyridine-4-carbonitrile (7) with MIC against Mycobacterium kansasii in the range of 8-4 mumol/l. The antifungal activities of the compounds were relatively low.

Anti-Bacterial Agents↗
PubMed1999

Fused 1,2-dithioles, V: Carbenoid anions as intermediates in reactions of pyrrothines and their heteroanalogues.

Pyrrothines like thiolutine and other bicyclic 1,2-dithioles of type 1 when unsubstituted in 3-position are marked by their CH acidity. In the presence of weak bases such as triethylamine the pyrrothine 4 degraded via its anion to a thioketene trapped as the 1,3-dithietane 5. The carbenoid anions of several compounds 1 reacted with elemental sulphur forming enthiolates whose alkylation led to the corresponding thioethers or, in the case of the thiolactam 9, to the bicyclic trithiones 10 and 11. In the same manner selenides can be obtained via intermediate selenolate ions. Introduction of an aryl- or heteroarylmercapto group into compounds 1 was achieved directly by reaction of the corresponding anions with suitable disulphides. Though there may be structural limitations, this sulphurization reaction can be extended to 3-unsubstituted trithiones. The new compounds exhibited significant activity against Mycobacterium tuberculosis in the primary screening.

Antitubercular Agents↗
PubMed1999

[Advances in the development of new antitubercular agents from a group of 5-membered heterocyclic compounds containing one type of heteroatom].

Tuberculosis and other mycobacterial diseases are considered at present to be one of the prominent problems of health services. Since 1985, and in particular in the 1990s, a search for new structures of antimycobacterial drugs is one of the first and foremost fields of chemotherapeutic research. The present review paper surveys the studies carried out in the field of five-membered heterocyclic compounds containing one species of the heteroatom (furan, thiophene, pyrrol, diazoles, triazoles, tetrazoles, indol, carbazol, and other more complex cyclic compounds of nitrogen and sulfur) since 1984, making use of the journal Chemical Abstracts and original papers.

Antitubercular Agents↗
PubMed1999

[Advances in the development of new antitubercular agents from a group of 5-membered heterocyclic compounds containing various heteroatoms].

Tuberculosis and other antimycobacterial diseases are considered to be one of the most important problems of the health service at present. Since 1985, and in particular in the 1990s, a search for new structures of antimycobacterial substances has ranked among the prior fields of chemotherapeutic research. The present review paper links up with the previous communications, and surveys the studies carried out in the field of five-membered heterocyclic compounds containing more heteroatoms since 1984. The most frequently investigated field is thiazole derivatives but the most successful papers originated in the group of oxazoles, where effective antituberculotics for clinical use can be expected in the future. The present research is based on the journal Chemical Abstracts and original papers.

Antitubercular Agents↗
PubMed1998

Relationships between the chemical structure of antimycobacterial substances and their activity against atypical strains. Part 14: 3-Aryl-6,8-dihalogeno-2H-1,3-benzoxazine-2,4(3H)-diones.

A set of eight derivatives of 6,8-dichloro-3-phenyl-2H-benzoxazine-2,4(3H)-dione and nine derivatives of 6,8-dibromo-3-phenyl-2H-1, 3-benzoxazine-2,4(3H)-dione, substituted on the phenyl ring, was prepared by the reaction of the corresponding salicylanilides with ethyl chloroformate. The compounds were evaluated in vitro for antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii, and Mycobacterium avium. Their activity increases with increasing hydrophobicity and electron-withdrawing ability of the substituents on the phenyl ring.

Anti-Bacterial Agents↗
PubMed1998

Antimycobacterial activity of 3'- and 4'-fluorothiobenzanilides.

On the basis of a preliminary study of the antimycobacterial activity of thiobenzanilides, a group of 3'-fluoro- and 4'-fluorothiobenzanilides has been synthesized and tested against Mycobacterium tuberculosis, M. kansasii, M. avium and M. fortuitum. The results of this study demonstrate that electron withdrawing groups increase the activity of thiobenzanilides and fluoro benzothioanilides against atypical strains which is higher then that of INH.

Anilides↗
PubMed1998

[Relation between chemical structure and antimycobacterial activity against atypical strains. XIII. Thiosalicylanilides].

On the basis of a preliminary study of antimycobacterial activity of thiobenzanilides a series of eight thiosalicylanilides have been prepared. Synthetized compounds have been examined in vitro against Mycobacterium tuberculosis, Mycobacterium kansasii, Mycobacterium avium and Mycobacterium fortuitum. All compounds have been found very active. The values of minimal inhibitory concentrations are summarized in Table 1. 3',4'-Salicylanilide was selected for the following research. The compound have been found inactive in vivo (on experimental murine tuberculosis).

Animals↗