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This work describes the demonstration of a kilogram-scale synthesis of a γ-secretase modulator from a plant-sterol-derived starting material. Key to developing a synthetic route capable of delivering a kilogram of the target compound was the development of a four-reaction telescope process and a selective O-alkylation of a triol intermediate. These improvements enabled the successful delivery of kilogram-scale batches of API for preclinical development studies.

The process development and production of two cycloartenol triterpenoid glycosides on a multikilogram scale are described. The two compounds were used as key intermediates for the synthesis of a γ-secretase modulator and a novel potential therapeutic agent for Alzheimer’s disease (SPI-1865). This practical and efficient process includes extraction of precursor triterpenoid glycosides from Actaea racemosa (black cohosh) and a ZrCl4-catalyzed rearrangement reaction.

Selectfluor® is an easy to handle, air-stable and powerful electrophilic fluorination agent that can be used in a novel oxidative Mannich-type carbon–carbon bond forming process to allylate electron deficient tertiary amines in moderate to good yields. This process is rapid, operationally simple, insensitive to atmospheric conditions and of potentially broad use, especially in the construction of homoallylamines.

We report herein a novel series of difluoropiperidine acetic acids as modulators of gamma-secretase. Synthesis of 2-aryl-3,3-difluoropiperidine analogs was facilitated by a unique and selective beta-difluorination with Selectfluor. Compounds 1f and 2c were selected for in vivo assessment and demonstrated selective lowering of Abeta42 in a genetically engineered mouse model of APP processing. Moreover, in a 7-day safety study, rats treated orally with compound 1f (250mg/kg per day, AUC(0-24)=2100microMh) did not exhibit Notch-related effects.

Ongoing clinical studies indicate that inhibitors of Class I and Class II histone deacetylase (HDAC) enzymes show great promise for the treatment of cancer. Zolinza® (SAHA, Zolinza®) was recently approved by the FDA for the treatment of the cutaneous manifestations of cutaneous T-cell lymphoma. As a part of an ongoing effort to identify novel small molecules to target these important enzymes, we have prepared several classes of amino acid-derived HDAC1 inhibitors. The design rationale and in vitro activity against the HDAC1 enzyme and HCT116 cell line are described in this letter.

A multigram synthesis of the C29−C51 subunit of altohyrtin C (spongistatin 2) has been accomplished. Union of this intermediate with the C1−C28 fragment and further elaboration furnished the natural product. Completion of the C29−C51 subunit began with the aldol coupling of the boron enolate derived from methyl ketone 8 and aldehyde 9. Acid-catalyzed deprotection/cyclization of the resulting diastereomeric mixture of addition products was conducted in a single operation to afford the E-ring of altohyrtin C. The diastereomer obtained through cyclization of the unwanted aldol product was subjected to an oxidation/reduction sequence to rectify the C35 stereocenter. The C45−C48 segment of the eventual triene side chain was introduced by addition of a functionalized Grignard reagent derived from (R)-glycidol to a C44 aldehyde. Palladium-mediated deoxygenation of the resulting allylic alcohol was followed by adjustment of protecting groups to provide reactivity suitable for the later stages of the synthesis. Th...

Early lead compounds in this gamma secretase modulator series were found to potently inhibit CYP3A4 and other human CYP isoforms increasing their risk of causing drug–drug-interactions (DDIs). Using structure–activity relationships and CYP3A4 structural information, analogs were developed that minimized this DDI potential. Three of these new analogs were further characterized by rat PK, rat PK/PD and rat exploratory toxicity studies resulting in selection of SPI-1865 (14) as a preclinical development candidate.

The identification and in vitro and in vivo characterization of a potent SHI-1:2 are described. Kinetic analysis indicated that biaryl inhibitors exhibit slow binding kinetics in isolated HDAC1 and HDAC2 preparations. Delayed histone hyperacetylation and gene expression changes were also observed in cell culture, and histone acetylation was observed in vivo beyond disappearance of drug from plasma. In vivo studies further demonstrated that continuous target inhibition was well tolerated and efficacious in tumor-bearing mice, leading to tumor growth inhibition with either once-daily or intermittent administration.

Introduction Modulation of the gamma-secretase enzyme, which reduces the production of the amyloidogenic Aβ42 peptide while sparing the production of other Aβ species, is a promising therapeutic approach for the treatment of Alzheimer's disease. Satori has identified a unique class of small molecule gamma-secretase modulators (GSMs) capable of decreasing Aβ42 levels in cellular and rodent model systems. The compound class exhibits potency in the nM range in vitro and is selective for lowering Aβ42 and Aβ38 while sparing Aβ40 and total Aβ levels. In vivo, a compound from the series, SPI-1865, demonstrates similar pharmacology in wild-type CD1 mice, Tg2576 mice and Sprague Dawley rats. Methods Animals were orally administered either a single dose of SPI-1865 or dosed for multiple days. Aβ levels were measured using a sensitive plate-based ELISA system (MSD) and brain and plasma exposure of drug were assessed by LC/MS/MS. Results In wild-type mice using either dosing regimen, brain Aβ42 and Aβ38 levels were decreased upon treatment with SPI-1865 and little to no statistically meaningful effect on Aβ40 was observed, reflecting the changes observed in vitro. In rats, brain Aβ levels were examined and similar to the mouse studies, brain Aβ42 and Aβ38 were lowered. Comparable changes were also observed in the Tg2576 mice, where Aβ levels were measured in brain as well as plasma and CSF. Conclusions Taken together, these data indicate that SPI-1865 is orally bioavailable, brain penetrant, and effective at lowering Aβ42 in a dose responsive manner. With this unique profile, the class of compounds represented by SPI-1865 may be a promising new therapy for Alzheimer's disease.

The discovery of a new series of γ-secretase modulators is disclosed. Starting from a triterpene glycoside γ-secretase modulator that gave a very low brain-to-plasma ratio, initial SAR and optimization involved replacement of a pendant sugar with a series of morpholines. This modification led to two compounds with significantly improved central nervous system (CNS) exposure.

The Amyloid Hypothesis states that the cascade of events associated with Alzheimer's disease (AD)—formation of amyloid plaques, neurofibrillary tangles, synaptic loss, neurodegeneration, and cognitive decline—are triggered by Aβpeptide dysregulation (Kakuda et al., 2006, Sato et al., 2003, Qi-Takahara et al., 2005). Sinceγ-secretase is critical for Aβproduction, many in the biopharmaceutical community focused onγ-secretase as a target for therapeutic approaches for Alzheimer's disease. However, pharmacological approaches to controlγ-secretase activity are challenging because the enzyme has multiple, physiologically critical protein substrates. To lower amyloidogenic Aβpeptides without affecting otherγ-secretase substrates, the epsilon (ε) cleavage that is essential for the activity of many substrates must be preserved. Small molecule modulators ofγ-secretase activity have been discovered that spare theεcleavage of APP and other substrates while decreasing the production of Aβ42. Multiple chemical classes ofγ-secretase modulators have been identified which differ in the pattern of Aβpeptides produced. Ideally, modulators will allow theεcleavage of all substrates while shifting APP cleavage from Aβ42and other highly amyloidogenic Aβpeptides to shorter and less neurotoxic forms of the peptides without altering the total Aβpool. Here, we compare chemically distinct modulators for effects on APP processing andin vivoactivity.

The process can be run with a variety of electron-poor tertiary amine substrates and different carbon nucleophiles.

The development of a novel series of purines as gamma-secretase modulators for potential use in the treatment of Alzheimer's disease is disclosed herein. Optimization of a previously disclosed pyrimidine series afforded a series of potent purine-based gamma-secretase modulators with 300- to 2000-fold in vitro selectivity over inhibition of Notch cleavage and that selectively reduces Alphabeta42 in an APP-YAC transgenic mouse model.

[formula: see text] Isoschizogamine has been prepared for the first time. The synthesis requires eight steps from a readily available ketone starting material and features an aminal-forming cyclization that is based on a proposed biosynthetic transformation.

A multigram synthesis of the C29-C51 subunit of altohyrtin C (spongistatin 2) has been accomplished. Union of this intermediate with the C1-C28 fragment and further elaboration furnished the natural product. Completion of the C29-C51 subunit began with the aldol coupling of the boron enolate derived from methyl ketone 8 and aldehyde 9. Acid-catalyzed deprotection/cyclization of the resulting diastereomeric mixture of addition products was conducted in a single operation to afford the E-ring of altohyrtin C. The diastereomer obtained through cyclization of the unwanted aldol product was subjected to an oxidation/reduction sequence to rectify the C35 stereocenter. The C45-C48 segment of the eventual triene side chain was introduced by addition of a functionalized Grignard reagent derived from (R)-glycidol to a C44 aldehyde. Palladium-mediated deoxygenation of the resulting allylic alcohol was followed by adjustment of protecting groups to provide reactivity suitable for the later stages of the synthesis. The diene functionality comprising the remainder of the C44-C51 side chain was constructed by addition of an allylzinc reagent to the unmasked C48 aldehyde and subsequent dehydration of the resulting alcohol. Completion of the synthesis of the C29-C51 subunit was achieved through conversion of the protected C29 alcohol into a primary iodide. The synthesis of the C29-C51 iodide required 44 steps with a longest linear sequence of 33 steps. From commercially available tri-O-acetyl-d-glucal, the overall yield was 6.8%, and 2 g of the iodide was prepared. The C29-C51 primary iodide was amenable to phosphonium salt formation, and the ensuing Wittig coupling with a C1-C28 intermediate provided a fully functionalized, protected seco-acid. Selective deprotection of the required silicon groups afforded an intermediate appropriate for macrolactonization, and, finally, global deprotection furnished altohyrtin C (spongistatin 2). This synthetic approach required 113 steps with a longest linear sequence of 37 steps starting from either tri-O-acetyl-d-glucal or (S)-malic acid.

In this communication we present details of our analog efforts within a novel series of gamma-secretase modulating compounds. Esters and carbamates were investigated as bioisosteres for a glycoside moiety present in an initial hit isolated from black cohosh extract. We identified elements within each series that retain the potency and selectivity of the initial lead while improving physicochemical properties.

An enantioselective aldol reaction of N-propionylthiazolidinethione and representative aldehydes is disclosed. The reaction is catalyzed by [Ni(S,S)-t-BuBox](Otf)2. Enolization is effected by 2,6-lutidine, and TMSOTf facilitates catalyst turnover. Syn diastereoselectivities range from 88:12 to 97:3, and enantioselectivities are 90% or greater. Both aromatic and enolizable aliphatic aldehydes are included within the scope of this aldol addition process.