Discovery of NBI-77860/GSK561679, a potent corticotropin-releasing factor (CRF1) receptor antagonist with improved pharmacokinetic properties.

Antagonists of the corticotropin-releasing factor (CRF) neuropeptide may prove effective in treating stress and anxiety related disorders. In an effort to identify antagonists with improved physico-chemical properties a new series of CRF(1) antagonists were designed to substitute the propyl groups at the C7 position of the pyrazolo[1,5-a]pyrimidine core of 1 with heterocycles. Compound (S)-8d was identified as a high affinity ligand with a pK(i) value of 8.

N-[6-amino-2-(heteroaryl)pyrimidin-4-yl]acetamides as A2A receptor antagonists with improved drug like properties and in vivo efficacy.

In the present article, we report on a strategy to improve the physical properties of a series of small molecule human adenosine 2A (hA2A) antagonists. One of the aromatic rings typical of this series of antagonists is replaced with a series of aliphatic groups, with the aim of disrupting crystal packing of the molecule to lower the melting point and in turn to improve the solubility. Herein, we describe the SAR of a new series of water-soluble 2,4,6-trisubstituted pyrimidines where R1 is an aromatic heterocycle, R2 is a short-chain alkyl amide, and the typical R3 aromatic heterocyclic substituent is replaced with an aliphatic amino substituent.

Lead optimization of 4-acetylamino-2-(3,5-dimethylpyrazol-1-yl)-6-pyridylpyrimidines as A2A adenosine receptor antagonists for the treatment of Parkinson's disease.

4-Acetylamino-2-(3,5-dimethylpyrazol-1-yl)-pyrimidines bearing substituted pyridyl groups as C-6 substituents were prepared as selective adenosine hA2A receptor antagonists for the treatment of Parkinson's disease. The 5-methoxy-3-pyridyl derivative 6g (hA2A Ki 2.3 nM, hA1 Ki 190 nM) was orally active at 3 mg/kg in a rat HIC model but exposure was poor in nonrodent species, presumably due to poor aqueous solubility.

2,6-Diaryl-4-acylaminopyrimidines as potent and selective adenosine A(2A) antagonists with improved solubility and metabolic stability.

In this report, the strategy and outcome of expanding SAR exploration to improve solubility and metabolic stability are discussed. Compound 35 exhibited excellent potency, selectivity over A(1) and improved solubility of >4 mg/mL at pH 8.0.

Synthesis of N-pyrimidinyl-2-phenoxyacetamides as adenosine A2A receptor antagonists.

A series of N-pyrimidinyl-2-phenoxyacetamide adenosine A(2A) antagonists is described. SAR studies led to compound 14 with excellent potency (K(i) = 0.4 nM), selectivity (A(1)/A(2A) > 100), and efficacy (MED 10 mg/kg p.

2-Amino-N-pyrimidin-4-ylacetamides as A2A receptor antagonists: 2. Reduction of hERG activity, observed species selectivity, and structure-activity relationships.

Previously we have described a series of novel A 2A receptor antagonists with excellent water solubility. As described in the accompanying paper, the antagonists were first optimized to remove an unsubstituted furyl moiety, with the aim of avoiding the potential metabolic liabilities that can arise from the presence of an unsubstituted furan. This effort identified a series of potent and selective methylfuryl derivatives.

2-Amino-N-pyrimidin-4-ylacetamides as A2A receptor antagonists: 1. Structure-activity relationships and optimization of heterocyclic substituents.

Previously we have described a novel series of potent and selective A 2A receptor antagonists (e.g., 1) with excellent aqueous solubility.

2,6-Diaryl-4-phenacylaminopyrimidines as potent and selective adenosine A(2A) antagonists with reduced hERG liability.

In this report, the design and synthesis of a series of pyrimidine based adenosine A(2A) antagonists are described. The strategy and outcome of expanding SAR exploration to attenuate hERG and improve selectivity over A(1) are discussed. Compound 33 exhibited excellent potency, selectivity over A(1), and reduced hERG liability.

Identification of novel, water-soluble, 2-amino-N-pyrimidin-4-yl acetamides as A2A receptor antagonists with in vivo efficacy.

Potent adenosine hA2A receptor antagonists are often accompanied by poor aqueous solubility, which presents issues for drug development. Herein we describe the early exploration of the structure-activity relationships of a lead pyrimidin-4-yl acetamide series to provide potent and selective 2-amino-N-pyrimidin-4-yl acetamides as hA2A receptor antagonists with excellent aqueous solubility. In addition, this series of compounds has demonstrated good bioavailability and in vivo efficacy in a rodent model of Parkinson's disease, despite having reduced potency for the rat A2A receptor versus the human A2A receptor.

Design and synthesis of tricyclic corticotropin-releasing factor-1 antagonists.

Antagonists of the corticotropin-releasing factor (CRF) neuropeptide should prove to be effective in treating stress and anxiety-related disorders. In an effort to identify antagonists with improved physicochemical properties, new tricyclic CRF(1) antagonists were designed, synthesized, and tested for biological activity. As a result of studies aimed at establishing a relationship between structure and CRF(1) binding affinity, NBI 35965 (12a) was identified as a high-affinity antagonist with a pK(i) value of 8.

Design and synthesis of tricyclic imidazo[4,5-b]pyridin-2-ones as corticotropin-releasing factor-1 antagonists.

The synthesis and SAR studies of tricyclic imidazo[4,5-b]pyridin-2-ones as human corticotropin-releasing factor receptor (CRF(1)) antagonists are discussed herein. Compound 16g was identified as a functional antagonist that inhibited CRF-stimulated cyclic adenosine monophosphate production and CRF-induced adrenocorticotrophic hormone release. Pharmacokinetics studies in rats showed that 16g was orally bioavailable, had good brain penetration, and had a moderate half-life.

Potent, orally active corticotropin-releasing factor receptor-1 antagonists containing a tricyclic pyrrolopyridine or pyrazolopyridine core.

Two new classes of tricyclic-based corticotropin-releasing factor (CRF(1)) receptor-1 antagonists were designed by constraining known 1H-pyrrolo[2,3-b]pyridine and 1H-pyrazolo[3,4-b]pyridine ligands. Pyrrole- and pyrazole-based molecules 19g and 22a, respectively, were discovered that potently bind the recombinant CRF(1) receptor (K(i) = 3.5, 2.

Synthesis and structure-activity relationships of uracil derived human GnRH receptor antagonists: (R)-3-[2-(2-amino)phenethyl]-1-(2,6-difluorobenzyl)-6-methyluracils containing a substituted thiophene or thiazole at C-5.

The synthesis of a series of (R)-3-[2-(2-amino)phenethyl]-1-(2,6-difluorobenzyl)-6-methyluracils containing a substituted thiophene or thiazole at C-5 is described. SAR around C-5 of the uracil led to the discovery that a 2-thienyl or (2-phenyl)thiazol-4-yl group is required for optimal receptor binding. The best compound from the series had a binding affinity of 2 nM (K(i)) for the human GnRH receptor.

Synthesis and structure-activity relationships of 1-arylmethyl-5-aryl-6-methyluracils as potent gonadotropin-releasing hormone receptor antagonists.

Based on the SAR from bicyclic gonadotropin-releasing hormone (GnRH) antagonists such as 6-aminomethyl-7-aryl-pyrrolo[1,2-a]pyrimid-4-ones (5) and 2-aryl-3-aminomethyl-imidazolo[1,2-a]pyrimid-5-ones (6a,b), a series of novel uracil compounds (8) were derived as GnRH antagonists. The synthesis and SAR studies of 6-methyluracils as human GnRH receptor antagonists are discussed herein. Introduction of a small methyl substituent at the beta-position of the N3 side-chain improved the GnRH binding potency by 5-10-fold.

Nanoerythrosomes, a new derivative of erythrocyte ghost II: identification of the mechanism of action.

We have recently developed a new drug which is a carrier from red blood cell membrane. This carrier, named nanoerythrosome (nEryt), is prepared by extrusion of erythrocyte ghosts to produce small vesicles having an average diameter of 100 nm. Daunorubicin (DNR) was covalently conjugated to the nEryt (nEryt-DNR) using glutaraldehyde as homobifunctional linking arm.

Nanoerythrosome, a new derivative of erythrocyte ghost: preparation and antineoplastic potential as drug carrier for daunorubicin.

Liposomes and monoclonal antibodies are used as drug carriers for the optimal delivery of pharmacologic agents. However, they present disadvantages that led us to develop a new model of drug carriers: the nanoerythrosomes. Nanoerythrosomes are vesicles prepared by the extrusion of red blood cell ghosts, the average diameter of these vesicles is 0.

AMMONIA: POSSIBLE USE FOR PRESERVING FISH.

Eviscerated oil sardines (Sardinella longiceps) that have been treated with ammonia can be stored at a temperature of 25 degrees to 30 degrees C for more than 2 months without deterioration of their nutritive value. There is no measurable residue of ammonia in the final product.