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Biomedical subjects

John E Macor

Publications and source records attributed to John E Macor.

15 recordsLinked to original sources
PubMed2006

A selective small molecule agonist of the melanocortin-1 receptor inhibits lipopolysaccharide-induced cytokine accumulation and leukocyte infiltration in mice.

It is well established that melanocortins are peptides that have potent anti-inflammatory activity. Recent research has focused on understanding which of the known melanocortin receptors mediates the anti-inflammatory actions of the melanocortins. The aim of this study was to assess the anti-inflammatory activity of a synthetic MC-1R agonist. BMS-470539 is a potent, selective, full agonist of human and murine MC-1R with EC(50) values in a cAMP accumulation assay of 16.8 and 11.6 nM, respectively. BMS-470539 dose-dependently inhibited TNF-alpha-induced activation of a NF-kappaB transcriptional reporter in human melanoma cells, which endogenously express MC-1R. In vivo studies with BMS-470539 demonstrated that subcutaneous administration of BMS-470539 resulted in a dose-dependent inhibition of LPS-induced TNF-alpha production in BALB/c mice. In this model, the compound had an ED(50) of approximately 10 micromol/kg and a pharmacodynamic half-life of approximately 8 h. Pharmacokinetic analysis of the compound indicated that the compound had a t(1/2) of 1.7 h. In a model of lung inflammation, administration of 15 micromol/kg BMS-470539 resulted in a 45% reduction in LPS-induced leukocyte infiltration (an infiltrate comprised primarily of neutrophils). The compound was also effective in a model of delayed-type hypersensitivity, reducing paw swelling by 59%, comparable with that seen with 5 mg/kg dexamethasone. These studies demonstrate that a selective small molecule agonist of the melanocortin-1 receptor is a potent anti-inflammatory agent in vivo and provides compelling evidence for the involvement of this receptor in the modulation of inflammation.

Animals↗
PubMed2005

Enantioselective synthesis of a highly potent selective serotonin reuptake inhibitor. An application of imidazolidinone catalysis to the alkylation of indoles with an alpha,beta-disubstituted alpha,beta-unsaturated aldehyde.

The synthesis of the highly potent and selective serotonin reuptake inhibitor 1 (BMS-594726) is described. In the key construction step, an enantioselective alkylation of the indole nucleus with an alpha-branched alpha,beta-unsaturated aldehyde 7 was accomplished utilizing MacMillan's imidazolidinone catalyst 3b. A rationale is presented for the unexpected stereochemical result, as well as the novel reactivity of the alpha-branched substrate. [reaction: see text]

Aldehydes↗
PubMed2005

Characterization of the in vitro atropisomeric interconversion rates of an endothelin A antagonist by enantioselective liquid chromatography.

Substituted biphenyl I (BMS-207940), a selective antagonist of the endothelin A (ETA) receptor, has been proposed for the treatment of congestive heart failure. The structure of I possesses a stereogenic axis due to the hindered rotation about the biphenyl bond in the presence of its large ortho-substituents. As a result, I exhibits atropisomerism in which two nonplanar, axially enantiomers exist, which will be generically referred to as isomers A and B. Within the pharmaceutical industry, both from a scientific and regulatory point of view, characterization of enantiomeric drugs has become an important step in the development process. To investigate the configurational stability of I atropisomers, normal phase enantiomeric LC with tandem UV and laser polarimetric detection was used under pseudo-physiological conditions: first in a simple aqueous medium at 37 degrees C, and then in human serum at 37 degrees C. Kinetic studies indicated that the half-life of I enantiomerization in an aqueous medium at 37 degrees C was ca. 15 h. Enantiomerization of I atropisomers was greatly accelerated in the presence of human serum and human serum albumin, and the rate of enantiomerization depended on the concentration of I. The sera-concentration-dependent enantiomerization behavior of I strongly suggests a restricted site-specific substrate/I interaction mechanism. It was therefore demonstrated that atropisomeric interconversion studies for the compound studied required consideration of temperature, presence of plasma proteins, and drug concentration to account for the kinetic data.

Biphenyl Compounds↗
PubMed2005

Stereoselective synthesis of new conformationally restricted analogues of a potent CGRP receptor antagonist.

[structures: see text] A stereocontrolled racemic synthesis of conformationally restricted analogues 2a and 2b of a potent CGRP receptor antagonist 1 by novel functionalization of 2-substituted octahydropyrido[1,2-a]pyrazin-6-ones is described. The new diastereoselective LDA-promoted alpha-nitration of intermediate lactams established the required trans-configuration in the desired products.

Benzimidazoles↗
PubMed2005

Homotryptamines as potent and selective serotonin reuptake inhibitors (SSRIs).

A series of N,N-dimethylhomotryptamines was prepared and their binding affinities at the serotonin transporter (SERT) were determined. Compounds possessing an electron withdrawing substituent at the C5-position of the indole nucleus were found to be potent SSRIs. Initial attempts at conformational restriction of the propylamine sidechain by incorporation of a quinuclidine bicyclic structure did not improve binding affinity at SERT.

Cell Line↗
PubMed2005

Tryptamine and homotryptamine-based sulfonamides as potent and selective inhibitors of 15-lipoxygenase.

A series of inhibitors of mammalian 15-lipoxygenase based on tryptamine and homotryptamine scaffolds is described. Compounds with aryl substituents at C-2 of the indole core of tryptamine and homotryptamine sulfonamides (e.g., 37a-p) proved to be potent inhibitors of the isolated enzyme. Selected compounds also demonstrated desirable inhibition selectivities over isozymes 5- and P-12-LO.

Animals↗
PubMed2005

Dual angiotensin II and endothelin A receptor antagonists: synthesis of 2'-substituted N-3-isoxazolyl biphenylsulfonamides with improved potency and pharmacokinetics.

In a previous report we demonstrated that merging together key structural elements present in an AT(1) receptor antagonist (1, irbesartan) with key structural elements in a biphenylsulfonamide ET(A) receptor antagonist (2) followed by additional optimization provided compound 3 as a dual-action receptor antagonist (DARA), which potently blocked both AT(1) and ET(A) receptors. Described herein are our efforts directed toward improving both the pharmacokinetic profile as well as the AT(1) and ET(A) receptor potency of 3. Our efforts centered on modifying the 2'-side chain of 3 and examining the isoxazolylsulfonamide moiety in 3. This effort resulted in the discovery of 7 as a highly potent second-generation DARA. Compound 7 also showed substantially improved pharmacokinetic properties compared to 3. In rats, DARA 7 reduced blood pressure elevations caused by intravenous infusion of Ang II or big ET-1 to a greater extent and with longer duration than DARA 3 or AT(1) or ET(A) receptor antagonists alone. Compound 7 clearly demonstrated superiority over irbesartan (an AT(1) receptor antagonist) in the normal SHR model of hypertension in a dose-dependent manner, demonstrating the synergy of AT(1) and ET(A) receptor blockade in a single molecule.

Administration, Oral↗
PubMed2004

A chiral synthesis of (-)-spiro[1-azabicyclo[2.2.2]octane-3,5'- oxazolidin-2'-one]: a conformationally restricted analogue of acetylcholine that is a potent and selective alpha7 nicotinic receptor agonist.

A direct, short chiral synthesis of the selective alpha7 nicotinic receptor agonist (-)-spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin-2'-one] (AR-R17779) is presented. The key step utilized attack of the dianion of the (R)-HYTRA ester [(R)-(+)-2-hydroxy-1,2,2-triphenylethyl acetate] on quinuclidin-3-one, followed by a selective precipitation of the diasteriomeric tertiary alcohol that led to (S)-(-)-AR-R17779 in two additional steps.

Bridged-Ring Compounds↗
PubMed2004

Quinolines as extremely potent and selective PDE5 inhibitors as potential agents for treatment of erectile dysfunction.

In a continuing effort to discover novel chemotypes as potent and selective PDE5 inhibitors for the treatment of male erectile dysfunction (ED), we have found that 4-benzylaminoquinoline derivatives are very potent and selective PDE5 inhibitors. Some compounds in this series had PDE5 IC(50)'s as low as 50 pM. While an electron withdrawing group at the C6-position of the quinoline substantially improved PDE5 potency, an ethyl group at the C8-position not only improved the PDE5 potency but also the isozyme selectivity. Substitutents at the C3-position can incorporate a variety of different groups. The synthesis and primary structure-activity relationship of this new series of potent PDE5 inhibitors are described.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2004

Novel dual action AT1 and ETA receptor antagonists reduce blood pressure in experimental hypertension.

Angiotensin II and endothelin-1 activate their respective AT(1) and ET(A) receptors on vascular smooth muscle cells, producing vasoconstriction, and both peptides are implicated in the pathogenesis of essential hypertension. Angiotensin II potentiates the production of endothelin, and conversely endothelin augments the synthesis of angiotensin II. Both AT(1) and ET(A) receptor antagonists lower blood pressure in hypertensive patients; thus, a combination AT(1)/ET(A) receptor antagonist may have greater efficacy and broader utility compared with each drug alone. By rational drug design a biphenyl ET(A) receptor blocker was modified to acquire AT(1) receptor antagonism. These compounds (C and D) decreased Sar-Ile-Angiotensin II binding to AT(1) receptors and endothelin-1 binding to ET(A) receptors, and compound C inhibited angiotensin II- and endothelin-1-mediated Ca(2+) transients. In rats compounds C and D reduced blood pressure elevations caused by intravenous infusion of angiotensin II or big endothelin-1. Compound C decreased blood pressure in Na(+)-depleted spontaneously hypertensive rats and in rats with mineralocorticoid hypertension. Compound D was more efficacious than AT(1) receptor antagonists at reducing blood pressure in spontaneously hypertensive rats, and its superiority was likely due to its partial blockade of ET(A) receptors. Therefore compounds C and D are novel agents for treating a broad spectrum of patients with essential hypertension and other cardiovascular diseases.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2003

Discovery of 4'-[(imidazol-1-yl)methyl]biphenyl-2-sulfonamides as dual endothelin/angiotensin II receptor antagonists.

A series of 4'-[(imidazol-1-yl)methyl]biphenylsulfonamides has potent antagonist activity against both angiotensin II AT(1) and endothelin ET(A) receptors. Such dual-acting antagonists could have utility in the treatment of hypertension, heart failure, and other cardiovascular diseases in a broad patient population. Certain compounds in the present series are orally active in a rat model of angiotensin II-mediated hypertension.

Angiotensin Receptor Antagonists↗
PubMed2003

Substituted pyrazolopyridopyridazines as orally bioavailable potent and selective PDE5 inhibitors: potential agents for treatment of erectile dysfunction.

Novel pyrazolopyridopyridazine derivatives have been prepared as potent and selective PDE5 inhibitors. Compound 6 has been identified as a more potent and selective PDE5 inhibitor than sildenafil (1). It is as efficacious as sildenafil in in vitro and in vivo PDE5 inhibition models, and it is orally bioavailable in rats and dogs. The superior isozyme selectivity of 6 is expected to exert less adverse effects in humans when used for erectile dysfunction treatment.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2002

Discovery of N-isoxazolyl biphenylsulfonamides as potent dual angiotensin II and endothelin A receptor antagonists.

The ET(A) receptor antagonist (2) (N-(3,4-dimethyl-5-isoxazolyl)-4'-(2-oxazolyl)-[1,1'-biphenyl]-2-sulfonamide, BMS-193884) shares the same biphenyl core as a large number of AT(1) receptor antagonists, including irbesartan (3). Thus, it was hypothesized that merging the structural elements of 2 with those of the biphenyl AT(1) antagonists (e.g., irbesartan) would yield a compound with dual activity for both receptors. This strategy led to the design, synthesis, and discovery of (15) (4'-[(2-butyl-4-oxo-1,3-diazaspiro[4.4]non-1-en-3-yl)methyl]-N-(3,4-dimethyl-5-isoxazolyl)-2'-[(3,3-dimethyl-2-oxo-1-pyrrolidinyl)methyl]-[1,1'-biphenyl]-2-sulfonamide, BMS-248360) as a potent and orally active dual antagonist of both AT(1) and ET(A) receptors. Compound 15 represents a new approach to treating hypertension.

Angiotensin II↗