Leonard L. Winneroski

Salt form selection and characterization of LY333531 mesylate monohydrate

LY333531 is a potent protein kinase C(beta) (PKC(beta)) inhibitor currently under development for the treatment of diabetic complications. Seven salts of LY333531 (hydrochloride, sulfate, mesylate, succinate, tartrate, acetate and phosphate) were evaluated during the early phase of development. Physical property screening techniques including microscopy, DSC, TGA, XRPD, hygroscopicity and solubility were utilized to narrow the selection to two salts: the mesylate and hydrochloride. Identification of the optimal salt form was based upon solubility, bioavailability, physical stability and purity. During the evaluation process three hydrated forms (anhydrate, monohydrate, and tetrahydrate) of the hydrochloride salt were identified. The mesylate salt was found to give only one, a monohydrate. Processing parameters (e.g. filtration rate, crystal form stability) demonstrated that the anhydrate was the preferred form of the hydrochloride salt. Bioavailability studies in dogs indicated that the C(max) and area under the plasma concentration vs. time curve (AUC) for LY333531 and its active metabolite, LY338522, following administration of the mesylate salt were approximately 2.6 times those obtained after the LY333531 HCl dose. This difference was presumed to be due primarily to the fact that the mesylate was five times more soluble than the hydrochloride salt in water. These factors led to selection and development of LY333531 mesylate monohydrate as the active pharmaceutical ingredient for clinical evaluation.

The Potent BACE1 Inhibitor LY2886721 Elicits Robust Central Aβ Pharmacodynamic Responses in Mice, Dogs, and Humans

BACE1 is a key protease controlling the formation of amyloid β, a peptide hypothesized to play a significant role in the pathogenesis of Alzheimers disease (AD). Therefore, the development of potent and selective inhibitors of BACE1 has been a focus of many drug discovery efforts in academia and industry. Herein, we report the nonclinical and early clinical development of LY2886721, a BACE1 active site inhibitor that reached phase 2 clinical trials in AD. LY2886721 has high selectivity against key off-target proteases, which efficiently translates in vitro activity into robust in vivo amyloid β lowering in nonclinical animal models. Similar potent and persistent amyloid β lowering was observed in plasma and lumbar CSF when single and multiple doses of LY2886721 were administered to healthy human subjects. Collectively, these data add support for BACE1 inhibition as an effective means of amyloid lowering and as an attractive target for potential disease modification therapy in AD.

A new one step synthesis of maleimides by condensation of glyoxylate esters with acetamides

Bisphenyl, Bisheteroaryl, indolylaryl and indolylcycloalkyl maleimides are prepared in one step and 67–99% yield by condensation of glyoxylate esters with acetamides using a 1.0 M solution of potassium tert-butoxide in THF. The mechanism of the reaction is discussed.

Aryl[a]pyrrolo[3,4-c]carbazoles as selective cyclin D1-CDK4 inhibitors

The synthesis of new analogues of Arcyriaflavin A in which one indole ring is replaced by an aryl or heteroaryl ring is described. These new series of aryl[a]pyrrolo[3,4-c]carbazoles were evaluated as inhibitors of Cyclin D1-CDK4. A potent and selective D1-CDK4 inhibitor, 7a (D1-CDK4 IC(50)=45 nM), has been identified. The potency, selectivity profile against other kinases, and structure-activity relationship (SAR) trends of this class of compounds are discussed.

PALLADIUM-CATALYZED ACYLATION OF A 1,2-DISUBSTITUTED 3-INDOLYLZINC CHLORIDE

Abstract 3-Acylindoles were prepared by pallladium catalyzed coupling of an acid sensitive 1,2-disubstituted 3-indolylzinc chloride with a number of acid chlorides to give the corresponding ketones in 33–74% yields.

Synthesis of 2′,3′-dideoxy-3′-hydroxymethylcytidine; a unique antiviral nucleoside

Abstract The synthesis of 2′,3′-dideoxy-3′-hydroxymethylcytidine 1 was accomplished using two different approaches. First, uridine and cytidine were used to prepare the key intermediate epoxides 15 and 31 which were opened with cyanide, deoxygenated by elimination to vinyl nitriles 17 and 36, and reduced by 1,4 hydride addition to the saturated nitriles 18 and 37. Secondly, a novel Rh-catalyzed hydroformylation reaction of 2′,3′-didehydro-2′,3′-dideoxycytidine 46 was used to prepare 1 in four steps. The attempted use of 2′-deoxyuridine and 2′-deoxycytidine to prepare 1 is also discussed.

Synthesis of bisindolylmaleimide macrocycles

Abstract The synthesis of a novel class of N-N′-macrocyclic bisindolylmaleimides is reported. The key step involves a remarkably efficient intramolecular cyclization reaction. The method was further developed to provide an efficient synthesis of this type of macrocycle through an intermolecular alkylation with subsequent intramolecular cyclization.

A CORRELATIONAL ANALYSIS OF EXPOSURE AND PHARMACODYNAMIC EFFECTS OF THE BACE1 INHIBITOR LY3202626 IN PDAPP MICE FOLLOWING ACUTE ORAL DOSING

Background: LY3202626 is a potent, freely CNS-penetrant small molecule BACE1 inhibitor in development for the treatment of Alzheimer’s disease (AD). Herein, we demonstrate strong pharmacokinetic / pharmacodynamic (PK/PD) relationships in PDAPP mice between central LY3202626 exposure and central (hippocampal and cortical brain tissue) BACE1 inhibition as determined by quantifying markers of amyloid precursor protein (APP) metabolism. Methods: In a dose response study, young female PDAPP mice (n1⁄46/group) were orally administered 0, 0.3, 1.0, or 3.0 mg LY3202626/kg and were sacrificed at 3 hr post-dose. In a separate time course study, young female PDAPP mice were sacrificed at 3, 6, 9, or 12 hours following a 3 mg LY3202626/kg oral dose. In all studies, LY3202626 concentrations were determined in plasma and brain samples by LC/MS/MS and concentrations of sAPPbeta, C99 and Abeta 1-X were determined in hippocampus and cortex using ELISA methodology. Results: Oral administration of LY3202626 to PDAPPmice produced dose-dependent reductions in brain Abeta, C99, and sAPPbeta with LY3202626 brain concentrations negatively-correlated with all three PD endpoints (r values > 0.56). Changes in each BACE1 biomarker were similar in the cortical and hippocampal brain regions (all r values > 0.90). In a timecourse study following a dose of 3 mg/kg LY3202626, free brain exposure over the 3-12 hour time-course study correlated well with hippocampal Abeta 1-X changes (r 1⁄4 0.60), indicating that the robust PK/PD relationship was maintained over time. All correlations were significant, with p-values <0.0001. Observed free (unbound) concentrations in brain and plasma across these studies suggest LY3202626 is highly brain penetrant in PDAPP mice. Conclusions:LY3202626 is a potent inhibitor of BACE1. Administration of LY3202626 results in significant changes in central biomarkers of BACE1 activity, and the magnitude of these changes correlate well with observed.