The asymmetric synthesis of the potent immunosuppressive agent (−)-pateamine A isolated from the marine sponge Mycale sp. is described. A key strategy employed in the synthesis was a β-lactam-based macrocyclization to form the 19-membered dilactone macrolide. The synthesis confirms the relative and absolute stereochemistry as 3R,5S,10S,24S and sets the stage for studies into the mechanism of action of pateamine A. Other studies and findings made in the course of the synthesis and described herein include the following:  (1) a Stille coupling can be competitive with π-allyl formation, (2) SmI2 effects a mild N−O cleavage of N-benzyloxy-β-lactams, (3) the synthesis of a pateamine A-dexamethasone hybrid molecule for use in a yeast three-hybrid assay was accomplished, and (4) IC50 values were determined for synthetic and natural pateamine A and related compounds in the interleukin 2 reporter gene assay.

A series of novel 4-oxopyrimidine TRPV1 antagonists was evaluated in assays measuring the blockade of capsaicin or acid-induced influx of calcium into CHO cells expressing TRPV1. The investigation of the structure-activity relationships in the heterocyclic A-region revealed the optimum pharmacophoric elements required for activity in this series and resulted in the identification of subnanomolar TRPV1 antagonists. The most potent of these antagonists were thoroughly profiled in pharmacokinetic assays. Optimization of the heterocyclic A-region led to the design and synthesis of 23, a compound that potently blocked multiple modes of TRPV1 activation. Compound 23 was shown to be effective in a rodent "on-target" biochemical challenge model (capsaicin-induced flinch, ED50 = 0.33 mg/kg p.o.) and was antihyperalgesic in a model of inflammatory pain (CFA-induced thermal hyperalgesia, MED = 0.83 mg/kg, p.o.). Based on its in vivo efficacy and pharmacokinetic profile, compound 23 (N-{4-[6-(4-trifluoromethyl-phenyl)-pyrimidin-4-yloxy]-benzothiazol-2-yl}-acetamide; AMG 517) was selected for further evaluation in human clinical trials.

Investigations into the structure-activity relationships (SAR) of a series of phthalazine-based inhibitors of p38 are described. These efforts originated from quinazoline 1 and through rational design led to the development of a series of orally bioavailable, potent, and selective inhibitors. Kinase selectivity was achieved by exploiting a collection of interactions with p38alpha including close contact to Ala157, occupation of the hydrophobic gatekeeper pocket, and a residue flip with Gly110. Substitutions on the phthalazine influenced the pharmacokinetic properties, of which compound 16 displayed the most desirable profile. Oral dosing (0.03 mg/kg) of 16 in rats 1 h prior to LPS challenge gave a >50% decrease in TNFalpha production.