Julien Grimont - Profile on Academia.edu (original) (raw)

Papers by Julien Grimont

Bioorganic & Medicinal Chemistry Letters, Dec 1, 2006

Malaria is a very serious infectious disease affecting over two billion people worldwide. Current... more Malaria is a very serious infectious disease affecting over two billion people worldwide. Currently available antimalarial drugs are losing effectiveness due to the emergence and the spread of resistant parasite strains. In order to regain control over the disease, new treatments are urgently needed. Drug discovery efforts in this direction are most likely to be successful if they target a novel mechanism of action. Such approaches will lead to antimalarial medicines that are functionally and structurally different from the existing drugs and therefore will have the potential to overcome existing resistances. Our own efforts are focused on the aspartic protease plasmepsin II (PMII) which is a promising new drug target for future antimalarial therapies. We have found structurally simple, moderately active, non-peptide inhibitors of plasmepsin II which offer ample opportunity for further optimization efforts.

CYP3A4 Catalyzes the Rearrangement of the Dual Orexin Receptor Antagonist Daridorexant to 4‐Hydroxypiperidinol Metabolites

ChemMedChem, Apr 12, 2023

The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the t... more The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the treatment of insomnia. The purpose of this study was the identification of its metabolic pathways and the human cytochrome P450 (P450) enzymes involved in its biotransformation. With human liver microsomes, daridorexant underwent hydroxylation at the methyl group of the benzimidazole moiety, oxidative O‐demethylation of the anisole to the corresponding phenol, and hydroxylation to a 4‐hydroxy piperidinol derivative. While the chemical structures of the benzylic alcohol and the phenol proved to be products of standard P450 reactions, 1D and 2D NMR data of the latter hydroxylation product was incompatible with the initially postulated hydroxylation of the pyrrolidine ring and suggested the disappearance of the pyrrolidine ring and formation of a new 6‐membered ring. Its formation is best explained by initial hydroxylation of the pyrrolidine ring in 5‐position to yield a cyclic hemiaminal. Hydrolytic ring opening then results in an aldehyde that subsequently cyclizes onto one of the benzimidazole nitrogen atoms to yield the final 4‐hydroxy piperidinol. The proposed mechanism was substantiated using an N‐methylated analogue, which might hydrolyze to the open‐chain aldehyde but cannot undergo the final cyclization step. CYP3A4 was the major P450 enzyme responsible for daridorexant metabolism, accounting for 89 % of metabolic turnover.

CYP3A4 Catalyzes the Rearrangement of the Dual Orexin Receptor Antagonist Daridorexant to 4‐Hydroxypiperidinol Metabolites

ChemMedChem

The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the t... more The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the treatment of insomnia. The purpose of this study was the identification of its metabolic pathways and the human cytochrome P450 (P450) enzymes involved in its biotransformation. With human liver microsomes, daridorexant underwent hydroxylation at the methyl group of the benzimidazole moiety, oxidative O‐demethylation of the anisole to the corresponding phenol, and hydroxylation to a 4‐hydroxy piperidinol derivative. While the chemical structures of the benzylic alcohol and the phenol proved to be products of standard P450 reactions, 1D and 2D NMR data of the latter hydroxylation product was incompatible with the initially postulated hydroxylation of the pyrrolidine ring and suggested the disappearance of the pyrrolidine ring and formation of a new 6‐membered ring. Its formation is best explained by initial hydroxylation of the pyrrolidine ring in 5‐position to yield a cyclic hemiaminal. H...

Journal of Medicinal Chemistry, 2014

In preceding communications we summarized our medicinal chemistry efforts leading to the identifi... more In preceding communications we summarized our medicinal chemistry efforts leading to the identification of potent, selective, and orally active S1P 1 agonists such as the thiophene derivative 1. As a continuation of these efforts, we replaced the thiophene in 1 by a 2-, 3-, or 4-pyridine and obtained less lipophilic, potent, and selective S1P 1 agonists (e.g., 2) efficiently reducing blood lymphocyte count in the rat. Structural features influencing the compounds' receptor affinity profile and pharmacokinetics are discussed. In addition, the ability to penetrate brain tissue has been studied for several compounds. As a typical example for these pyridine based S1P 1 agonists, compound 53 showed EC 50 values of 0.6 and 352 nM for the S1P 1 and S1P 3 receptor, respectively, displayed favorable PK properties, and penetrated well into brain tissue. In the rat, compound 53 maximally reduced the blood lymphocyte count for at least 24 h after oral dosing of 3 mg/kg.

Inhibitors of Plasmepsin II—potential antimalarial agents

Bioorganic & Medicinal Chemistry Letters, 2006

In order to overcome the problem of drug resistance in malaria, it appears wise to concentrate dr... more In order to overcome the problem of drug resistance in malaria, it appears wise to concentrate drug discovery efforts toward new structural classes and new mechanisms of action. We report our results, targeting Plasmepsin II, a Plasmodium falciparum aspartic protease active in hemoglobin degradation, a parasite specific catabolic pathway. The results show that the new structural class is not only inhibiting PMII in vitro but is also active in a P. falciparum infected human red blood cell assay.

Journal of Medicinal Chemistry, 2014

In preceding communications we summarized our medicinal chemistry efforts leading to the identifi... more In preceding communications we summarized our medicinal chemistry efforts leading to the identification of potent, selective, and orally active S1P 1 agonists such as the thiophene derivative 1. As a continuation of these efforts, we replaced the thiophene in 1 by a 2-, 3-, or 4-pyridine and obtained less lipophilic, potent, and selective S1P 1 agonists (e.g., 2) efficiently reducing blood lymphocyte count in the rat. Structural features influencing the compounds' receptor affinity profile and pharmacokinetics are discussed. In addition, the ability to penetrate brain tissue has been studied for several compounds. As a typical example for these pyridine based S1P 1 agonists, compound 53 showed EC 50 values of 0.6 and 352 nM for the S1P 1 and S1P 3 receptor, respectively, displayed favorable PK properties, and penetrated well into brain tissue. In the rat, compound 53 maximally reduced the blood lymphocyte count for at least 24 h after oral dosing of 3 mg/kg.

Bioorganic & Medicinal Chemistry Letters, Dec 1, 2006

Malaria is a very serious infectious disease affecting over two billion people worldwide. Current... more Malaria is a very serious infectious disease affecting over two billion people worldwide. Currently available antimalarial drugs are losing effectiveness due to the emergence and the spread of resistant parasite strains. In order to regain control over the disease, new treatments are urgently needed. Drug discovery efforts in this direction are most likely to be successful if they target a novel mechanism of action. Such approaches will lead to antimalarial medicines that are functionally and structurally different from the existing drugs and therefore will have the potential to overcome existing resistances. Our own efforts are focused on the aspartic protease plasmepsin II (PMII) which is a promising new drug target for future antimalarial therapies. We have found structurally simple, moderately active, non-peptide inhibitors of plasmepsin II which offer ample opportunity for further optimization efforts.

CYP3A4 Catalyzes the Rearrangement of the Dual Orexin Receptor Antagonist Daridorexant to 4‐Hydroxypiperidinol Metabolites

ChemMedChem, Apr 12, 2023

The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the t... more The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the treatment of insomnia. The purpose of this study was the identification of its metabolic pathways and the human cytochrome P450 (P450) enzymes involved in its biotransformation. With human liver microsomes, daridorexant underwent hydroxylation at the methyl group of the benzimidazole moiety, oxidative O‐demethylation of the anisole to the corresponding phenol, and hydroxylation to a 4‐hydroxy piperidinol derivative. While the chemical structures of the benzylic alcohol and the phenol proved to be products of standard P450 reactions, 1D and 2D NMR data of the latter hydroxylation product was incompatible with the initially postulated hydroxylation of the pyrrolidine ring and suggested the disappearance of the pyrrolidine ring and formation of a new 6‐membered ring. Its formation is best explained by initial hydroxylation of the pyrrolidine ring in 5‐position to yield a cyclic hemiaminal. Hydrolytic ring opening then results in an aldehyde that subsequently cyclizes onto one of the benzimidazole nitrogen atoms to yield the final 4‐hydroxy piperidinol. The proposed mechanism was substantiated using an N‐methylated analogue, which might hydrolyze to the open‐chain aldehyde but cannot undergo the final cyclization step. CYP3A4 was the major P450 enzyme responsible for daridorexant metabolism, accounting for 89 % of metabolic turnover.

CYP3A4 Catalyzes the Rearrangement of the Dual Orexin Receptor Antagonist Daridorexant to 4‐Hydroxypiperidinol Metabolites

ChemMedChem

The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the t... more The dual orexin receptor antagonist daridorexant was approved in 2022 in the USA and EU for the treatment of insomnia. The purpose of this study was the identification of its metabolic pathways and the human cytochrome P450 (P450) enzymes involved in its biotransformation. With human liver microsomes, daridorexant underwent hydroxylation at the methyl group of the benzimidazole moiety, oxidative O‐demethylation of the anisole to the corresponding phenol, and hydroxylation to a 4‐hydroxy piperidinol derivative. While the chemical structures of the benzylic alcohol and the phenol proved to be products of standard P450 reactions, 1D and 2D NMR data of the latter hydroxylation product was incompatible with the initially postulated hydroxylation of the pyrrolidine ring and suggested the disappearance of the pyrrolidine ring and formation of a new 6‐membered ring. Its formation is best explained by initial hydroxylation of the pyrrolidine ring in 5‐position to yield a cyclic hemiaminal. H...

Journal of Medicinal Chemistry, 2014

In preceding communications we summarized our medicinal chemistry efforts leading to the identifi... more In preceding communications we summarized our medicinal chemistry efforts leading to the identification of potent, selective, and orally active S1P 1 agonists such as the thiophene derivative 1. As a continuation of these efforts, we replaced the thiophene in 1 by a 2-, 3-, or 4-pyridine and obtained less lipophilic, potent, and selective S1P 1 agonists (e.g., 2) efficiently reducing blood lymphocyte count in the rat. Structural features influencing the compounds' receptor affinity profile and pharmacokinetics are discussed. In addition, the ability to penetrate brain tissue has been studied for several compounds. As a typical example for these pyridine based S1P 1 agonists, compound 53 showed EC 50 values of 0.6 and 352 nM for the S1P 1 and S1P 3 receptor, respectively, displayed favorable PK properties, and penetrated well into brain tissue. In the rat, compound 53 maximally reduced the blood lymphocyte count for at least 24 h after oral dosing of 3 mg/kg.

Inhibitors of Plasmepsin II—potential antimalarial agents

Bioorganic & Medicinal Chemistry Letters, 2006

In order to overcome the problem of drug resistance in malaria, it appears wise to concentrate dr... more In order to overcome the problem of drug resistance in malaria, it appears wise to concentrate drug discovery efforts toward new structural classes and new mechanisms of action. We report our results, targeting Plasmepsin II, a Plasmodium falciparum aspartic protease active in hemoglobin degradation, a parasite specific catabolic pathway. The results show that the new structural class is not only inhibiting PMII in vitro but is also active in a P. falciparum infected human red blood cell assay.

Journal of Medicinal Chemistry, 2014

In preceding communications we summarized our medicinal chemistry efforts leading to the identifi... more In preceding communications we summarized our medicinal chemistry efforts leading to the identification of potent, selective, and orally active S1P 1 agonists such as the thiophene derivative 1. As a continuation of these efforts, we replaced the thiophene in 1 by a 2-, 3-, or 4-pyridine and obtained less lipophilic, potent, and selective S1P 1 agonists (e.g., 2) efficiently reducing blood lymphocyte count in the rat. Structural features influencing the compounds' receptor affinity profile and pharmacokinetics are discussed. In addition, the ability to penetrate brain tissue has been studied for several compounds. As a typical example for these pyridine based S1P 1 agonists, compound 53 showed EC 50 values of 0.6 and 352 nM for the S1P 1 and S1P 3 receptor, respectively, displayed favorable PK properties, and penetrated well into brain tissue. In the rat, compound 53 maximally reduced the blood lymphocyte count for at least 24 h after oral dosing of 3 mg/kg.