Discovery of +(2-{4-[2-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)ethoxy]phenyl}-cyclopropyl)acetic acid as potent and selective alphavbeta3 inhibitor: design, synthesis, and optimization.

The integrin alpha(v)beta(3) is expressed in a number of cell types and is thought to play a major role in several pathological conditions. Various small molecules that inhibit the integrin have been shown to suppress tumor growth and retinal angiogenesis. The tripeptide Arg-Gly-Asp (RGD), a common binding motif in several ligands that bind to alpha(v)beta(3), has been depeptidized and optimized in our efforts toward discovering a small molecule inhibitor. We recently disclosed the synthesis and biological activity of several small molecules that did not contain any peptide bond and mimic the tripeptide RGD. The phenethyl group in one of the lead compounds was successfully replaced with a cyclopropyl moiety. The new lead compound was optimized for potency, selectivity, and for its ADME properties. We describe herein the discovery, synthesis, and optimization of cyclopropyl containing analogs that are potent and selective inhibitors of alpha(v)beta(3).

Synthesis of pyrazoles and isoxazoles as potent alpha(v)beta3 receptor antagonists.

We describe a series of pyrazole and isoxazole analogs as antagonists of the alpha(v)beta3 receptor. Compounds showed low to sub-nanomolar potency against alpha(v)beta3, as well as good selectivity against alpha(IIb)beta3. In HT29 cells, most analogs also demonstrated significant selectivity against alpha(v)beta6. Several compounds showed good pharmacokinetic properties in rats, in addition to anti-angiogenic activity in a mouse corneal micropocket model. Compounds were synthesized in a straightforward manner from readily available glutarate precursors.

Convergent, parallel synthesis of a series of beta-substituted 1,2,4-oxadiazole butanoic acids as potent and selective alpha(v)beta3 receptor antagonists.

We describe a series of 1,2,4-oxadiazoles, which are potent antagonists of the integrin alpha(v)beta3 and, in addition, show selectivity relative to the other beta3 integrin alpha(IIb)beta3. In whole cells, the majority of these analogs also demonstrated modest selectivity against other alpha(v) integrins such as alpha(v)beta1 and alpha(v)beta6.

Synthesis of 2,5-thiazole butanoic acids as potent and selective alpha(v)beta3 integrin receptor antagonists with improved oral pharmacokinetic properties.

We describe a series of 2,5 thiazole containing compounds, which are potent antagonists of the integrin alpha(v)beta3 and show selectivity relative to the other integrins, such as alpha(IIb)beta3 and alpha(v)beta6. These analogs were demonstrated to have high bioavailability relative to other relative heterocyclic analogs.

Synthesis of cinnamic acids and related isosteres as potent and selective alpha v beta 3 receptor antagonists.

We describe a series of conformationally-restricted cinnamic acid peptidomimetics as well as several cinnamic acid isosteres, including 3-phenylpropionic acids, 2-amino-3-phenylpropionic acids, phenoxyacetic acids and 2-phenylcyclopropylcarboxylic acids. Several analogues demonstrated low to sub-nanomolar potencies against alpha(v)beta(3) and greater than 200-fold selectivity against the other beta(3) integrin alpha(IIb)beta(3). In whole 293 cells, many of these analogues also showed modest selectivity against other alpha(v) integrins such as alpha(v)beta(1) and alpha(v)beta(5). These compounds were synthesized from readily available starting materials using either Heck or Mitsunobu coupling conditions.

Synthesis of potent leukotriene A(4) hydrolase inhibitors. Identification of 3-[methyl[3-[4-(phenylmethyl)phenoxy]propyl]amino]propanoic acid.

Leukotriene B(4) (LTB(4)) is a potent, proinflammatory mediator involved in the pathogenesis of a number of diseases including inflammatory bowel disease, psoriasis, rheumatoid arthritis, and asthma. The enzyme LTA(4) hydrolase represents an attractive target for pharmacological intervention in these disease states, since the action of this enzyme is the rate-limiting step in the production of LTB(4). Our previous efforts focused on the exploration of a series of analogues related to screening hit SC-22716 (1, 1-[2-(4-phenylphenoxy)ethyl]pyrrolidine) and resulted in the identification of potent, orally active inhibitors such as 2. Additional structure-activity relationship studies around this structural class resulted in the identification of a series of alpha-, beta-, and gamma-amino acid analogues that are potent inhibitors of the LTA(4) hydrolase enzyme and demonstrated good oral activity in a mouse ex vivo whole blood LTB(4) production assay. The efforts leading to the identification of clinical candidate SC-57461A (8d, 3-[methyl[3-[4-(phenylmethyl)phenoxy]propyl]amino]propanoic acid) are described.