Discovery of 5-Azaquinoxaline Derivatives as Potent and Orally Bioavailable Allosteric SHP2 Inhibitors.

SHP2 has emerged as an important target for oncology small-molecule drug discovery. As a nonreceptor tyrosine phosphatase within the MAPK pathway, it has been shown to control cell growth, differentiation, and oncogenic transformation. We used structure-based design to find a novel class of potent and orally bioavailable SHP2 inhibitors. Our efforts led to the discovery of the 5-azaquinoxaline as a new core for developing this class of compounds. Optimization of the potency and properties of this scaffold generated compound 30, that exhibited potent in vitro SHP2 inhibition and showed excellent in vivo efficacy and pharmacokinetic profile.

Discovery of a series of 2-(1H-pyrazol-1-yl)pyridines as ALK5 inhibitors with potential utility in the prevention of dermal scarring.

A series of 2-(1H-pyrazol-1-yl)pyridines are described as inhibitors of ALK5 (TGFß receptor I kinase). Modeling compounds in the ALK5 kinase domain enabled some optimization of potency via substitutions on the pyrazole core. One of these compounds PF-03671148 gave a dose dependent reduction in TGFß induced fibrotic gene expression in human fibroblasts. A similar reduction in fibrotic gene expression was observed when PF-03671148 was applied topically in a rat wound repair model. Thus these compounds have potential utility for the prevention of dermal scarring.

5-Alkyl-2-urea-Substituted Pyridines: Identification of Efficacious Glucokinase Activators with Improved Properties.

Two 1-(4-aryl-5-alkyl-pyridin-2-yl)-3-methylurea glucokinase activators were identified with robust in vivo efficacy. These two compounds possessed higher solubilities than the previously identified triaryl compounds (i.e., AM-2394). Structure-activity relationship studies are presented along with relevant pharmacokinetic and in vivo data.

Total Synthesis of (+)-Papuamine: An Antifungal Pentacyclic Alkaloid from a Marine Sponge, Haliclona sp.

The total synthesis of (+)-papuamine, the antipode of the C(2)-symmetric, optically active, pentacyclic diamine natural product, starting from a chiral diol is described. The diol is available via an asymmetric Diels-Alder reaction between 1,3-butadiene and di-(-)-menthyl fumarate. The key transformation in the synthesis is an intramolecular Pd(0)-catalyzed (Stille) coupling reaction to form the central 13-membered diazadiene macrocyclic ring.

Rational design and synthesis of 4-((1R,2R)-2-hydroxycyclohexyl)-2(trifluoromethyl)benzonitrile (PF-998425), a novel, nonsteroidal androgen receptor antagonist devoid of phototoxicity for dermatological indications.

4-((1 R,2 R)-2-Hydroxycyclohexyl)-2(trifluoromethyl)benzonitrile [PF-0998425, (-)- 6a] is a novel, nonsteroidal androgen receptor antagonist for sebum control and treatment of androgenetic alopecia. It is potent, selective, and active in vivo. The compound is rapidly metabolized systemically, thereby reducing the risk of unwanted systemic side effects due to its primary pharmacology. (-)- 6a was tested negative in the 3T3 NRU assay, validating our rationale that reduction of conjugation might reduce potential phototoxicity.

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.

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.

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.

Practical enantioselective synthesis of beta-substituted-beta-amino esters.

[reaction: see text] A practical, large-scale synthesis of a beta-amino ester 1 was developed. A chiral imine derived from (S)-phenylglycinol and 3-trimethylsilylpropanal was coupled with the Reformatsky reagent 3 with high diastereoselectivity (de > 98%) to give (SS)-4a as the major isomer. The amino alcohol residue of the coupling product 4 was oxidatively cleaved with sodium periodate in the presence of methylamine. An unusual selective oxidative cleavage of the (SS)-isomer was observed and the imine 6 was obtained with ee > 99% while the (RS)-4b isomer was not cleaved. Reaction with p-toluenesulfonic acid monohydrate allowed for the hydrolysis of the imine and the isolation of the amine as its salt. The title compound 1 was then obtained by transesterification, desilylation, and hydrochloride salt formation in a one-pot process. The method was successfully applied toward the synthesis of a wide variety of beta-amino esters.