Koen Muylaert

Synthesis Of Pyrido-Annelated Seven-Membered N-Containing Heterocycles.

Pharmaceutical industry is struggling with a lack of potential drugs in the pipe line. However, there is still a great opportunity to elaborate interesting scaffolds for medicinal chemistry. Various scaffolds that hold promise are rarely described in the literature. The last couple of decades, the wide range of biological activities of benzodiazepine derivatives have been investigated thoroughly and make the benzodiazepine scaffold, particularly the 1,4-benzodiazepine system, one of the most important structures for drug discovery. The substantial research on benzodiazepines has led to the synthesis of heterocycle-fused azepine derivatives with potentially new pharmacological activity. Some pyridoazepines are known to be active in the central nervous system and have a comparable activity to the well-known benzodiazepine scaffolds, which make the synthesis and study of pyridoazepines an important research topic.

Straightforward entry to pyrido[2,3-d]pyrimidine-2,4(1H,3H)-diones and their ADME properties.

A straightforward synthesis of pyrido[2,3-d]pyrimidine-2,4(1H,3H)-diones was developed starting from 2-chloropyridine-3-carboxylic acid by esterification, nucleophilic aromatic substitution and amide formation in one step, and ring closure allowing their synthesis with two identical or two different group attached to nitrogen. The structural diversity of these [2,3-d]pyrimidine-2,4(1H,3H)-diones resulted in significant variation in the biopharmaceutical properties. This was reflected by the broad range in fasted state simulated intestinal fluid solubility values (12.6 μM to 13.8 mM), Caco-2 permeability coefficients (1.2 × 10(-6)cm/s to 90.7 × 10(-6)cm/s) and in vitro-predicted human in vivo intrinsic clearance values (0 to 159 ml/min/kg).

Synthesis of Pyrido-annelated Diazepines, Oxazepines and Thiazepines

The immense amount of research on benzodiazepines resulted in the synthesis of heterocycle-fused diazepine derivatives with potential pharmacological activity. Pyridoazepines are recognized to be active in the central nervous system and have a comparable activity to the well-known benzodiazepines. This makes the synthesis and the study of pyridodiazepines an important research topic. This review comprises of the synthesis and activity of pyridodiazepines, pyridooxazepines and pyridothiazepines. Although these structures have a great similarity with benzodiazepines, much less work has been published on their synthesis or derivatization. Therefore, there is a need to further develop these classes of underexplored scaffolds, in search for new chemistry, new methodology and hence new biological features.

Beyond the Diketopiperazine Family with Alternatively Bridged Brevianamide F Analogues.

A method for the preparation of 3,5-bridged piperazin-2-ones from a tryptophan-proline-based diketopiperazine is described using diphosgene to induce the ring closure. Density functional theory calculations were conducted to study the mechanism of this C-C bond formation. Several derivatives of the thus obtained α-chloroamine were synthesized by substitution of the chlorine atom using a range of O-, N-, S-, and C-nucleophiles. This novel class of brevianamide F analogues possess interesting breast cancer resistance protein inhibitory activity.