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A Haemers

Publications and source records attributed to A Haemers.

At least 37 records · Page 2Linked to original sources
PubMed1991

Quinolone antimicrobial agents: structure-activity relationships.

The rapid growth in the quinolone research changed the whole face of the previous SAR concepts. So far structural modifications at all positions of the quinolone nucleus except the 4-oxo group have successfully lead to the discovery of potent antimicrobial agents. At position 1, ethyl and its bioisosteres such as fluoroethyl, methylamino, methoxy, etc, are optimal substituents while some groups with a tert.-carbon atom directly connected with N-1 position such as tert.-butyl, phenyl, etc. are also promising for the activity of the quinolone compounds. Steric bulk is no longer considered as the only factor which influences the activity of the compounds. However, it could only be answered by further research how big such steric bulk tolerance at position 1 would be and what is the precise role that the N-1 substituents play in the mechanism of action of the quinolones. Fluorination has been extensively employed as a modifying technique to almost all possible positions of the quinolone nucleus. While being maintained at C-6, a fluorine atom was also introduced to C-5 and C-8 to produce potent analogues. Fluorination of N-1 substituents, e.g., fluoroethyl, fluorophenyl, etc., and C-7 substituents, e.g. 2-((fluoromethyl)piperazinyl and fluorohomopiperazinyl, etc., yielded also a handful of potent quinolones. Amino-and chloro groups are found to be beneficial for positions 5 and 8, respectively. The "medium size" concept concerning the 7-substituents is no longer valid. Numerous potent quinolones with a "large" group substituted on position 7 have been discovered. A certain amount of free rotation in the 7-substituents appears to emerge as an important factor which influences the activity of the compounds. Some radical modifications in 7-substituents, e.g. C--C linkage between the nucleus and 7-substituents, afforded new insight into the SAR of quinolones. A planarity between the 4-oxo group and 3-carboxylic group may be important for binding to the DNA gyrase as demonstrated by a group of enolized isothiazoloquinolone derivatives. Further research will surely lead to the better understanding on the mechanism of action of quinolones as well as the discovery of analogues with better activity features, lower adverse effects and more favourable pharmacokinetic properties.

4-Quinolones↗
PubMed1990

Influence of N substitution on antimycobacterial activity of ciprofloxacin.

Ciprofloxacin analogs with various substitutions on the piperazine nitrogen were tested against several mycobacteria. In contrast to what has been found with other gram-positive and gram-negative bacteria, alkyl analogs such as N-isopropylciprofloxacin were shown to be significantly more active than ciprofloxacin. MICs of 0.125 microgram/ml against Mycobacterium tuberculosis were found.

Ciprofloxacin↗
PubMed1989

Eflornithine. A new drug in the treatment of sleeping sickness.

Eflornithine (alpha-difluoromethylornithine; DFMO) is a recently developed drug against African trypanosomiasis (sleeping sickness). After a short description of trypanosomiasis and the current treatment, the mechanism of action of eflornithine is discussed, some clinical data is given and attention is paid to recently discovered analogues of eflornithine. Some examples of combination therapy with eflornithine and possible applications are mentioned.

Animals↗
PubMed1987

Postoperative biliocutaneous fistula: successful treatment by insertion of an endoprosthesis.

An elderly patient with a postoperative biliocutaneous fistula, the persistence of which was due to an unrecognized fibro-malignant stricture of the distal common bile duct, was treated by the insertion of an endoscopic biliary endoprosthesis. Immediately after the procedure, bile discharge through the fistula ceased completely, and the fistula closed in three days. Endoscopic treatment methods are worth trying before surgical revision of a biliocutaneous fistula is performed.

Aged↗
PubMed1987

The mycobacterial cell-wall as target for antimycobacterial drugs. I--Synthesis and activity of some diphenylalkylanalogues of mycolic acids.

Mycolic acids are 2-alkyl-3-hydroxyfatty acids and are essential parts of the peptidoglycan of mycobacteria. Potential antimetabolites were prepared by substituting a longchain alkylgroup by a diphenylmethylfunction. 3-Oxo esters and 3-hydroxy esters and acids were prepared. The 3-oxo esters showed a slight activity against M. tuberculosis and some atypical mycobacteria.

Anti-Bacterial Agents↗