Publications by authors named "Brad M Savall"

21 Publications

  • Page 1 of 1

Discovery of Imidazo[1,2-]pyrazines and Pyrazolo[1,5-]pyrimidines as TARP γ-8 Selective AMPAR Negative Modulators.

ACS Med Chem Lett 2019 Mar 26;10(3):267-272. Epub 2018 Dec 26.

Janssen Research & Development L.L.C., 3210 Merryfield Row, San Diego, California 92121 United States.

This report discloses the discovery and characterization of imidazo[1,2-]pyrazines and pyrazolo[1,5-]pyrimidines as selective negative modulators of α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPARs) associated with transmembrane AMPAR regulatory protein γ-8. Imidazopyrazine was initially identified as a promising γ-8 selective high-throughput screening hit, and subsequent structure-activity relationship optimization yielded subnanomolar, brain penetrant leads. Replacement of the imidazopyrazine core with an isosteric pyrazolopyrimidine scaffold improved microsomal stability and efflux liabilities to provide , JNJ-61432059. Following oral administration, exhibited time- and dose-dependent AMPAR/γ-8 receptor occupancy in mouse hippocampus, which resulted in robust seizure protection in corneal kindling and pentylenetetrazole (PTZ) anticonvulsant models.
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http://dx.doi.org/10.1021/acsmedchemlett.8b00599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6421542PMC
March 2019

Lead Optimization of 5-Aryl Benzimidazolone- and Oxindole-Based AMPA Receptor Modulators Selective for TARP γ-8.

ACS Med Chem Lett 2018 Aug 13;9(8):821-826. Epub 2018 Jul 13.

Janssen Research & Development L.L.C., 3210 Merryfield Row, San Diego, California 92121, United States.

Glutamate mediates fast excitatory neurotransmission via ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The trafficking and gating properties of AMPA receptors (AMPARs) can be amplified by transmembrane AMPAR regulatory proteins (TARPs), which are often expressed in localized brain regions. Herein, we describe the discovery, lead optimization, and preclinical characterization of 5-arylbenzimidazolone and oxindole-based negative modulators of AMPARs associated with TARP γ-8, the primary TARP found in hippocampus. High-throughput screen lead was optimized for potency and brain penetration to provide benzimidazolone , JNJ-55511118.1 Replacement of the benzimidazolone core in with an oxindole mitigated reactive metabolite formation and led to the identification of (GluA1/γ-8 pIC = 9.7). Following oral dosing in rats, demonstrated robust target engagement in hippocampus as assessed by autoradiography (ED = 0.6 mg/kg, plasma EC = 9 ng/mL).
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http://dx.doi.org/10.1021/acsmedchemlett.8b00215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6088354PMC
August 2018

4-Methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridine-Based P2X7 Receptor Antagonists: Optimization of Pharmacokinetic Properties Leading to the Identification of a Clinical Candidate.

J Med Chem 2017 06 25;60(11):4559-4572. Epub 2017 May 25.

Janssen Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

The synthesis and preclinical characterization of novel 4-(R)-methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridines that are potent and selective brain penetrant P2X7 antagonists are described. Optimization efforts based on previously disclosed unsubstituted 6,7-dihydro-4H-triazolo[4,5-c]pyridines, methyl substituted 5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazines, and several other series lead to the identification of a series of 4-(R)-methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridines that are selective P2X7 antagonists with potency at the rodent and human P2X7 ion channels. These novel P2X7 antagonists have suitable physicochemical properties, and several analogs have an excellent pharmacokinetic profile, good partitioning into the CNS and show robust in vivo target engagement after oral dosing. Improvements in metabolic stability led to the identification of JNJ-54175446 (14) as a candidate for clinical development. The drug discovery efforts and strategies that resulted in the identification of the clinical candidate are described herein.
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http://dx.doi.org/10.1021/acs.jmedchem.7b00408DOI Listing
June 2017

Identification of (R)-(2-Chloro-3-(trifluoromethyl)phenyl)(1-(5-fluoropyridin-2-yl)-4-methyl-6,7-dihydro-1H-imidazo[4,5-c]pyridin-5(4H)-yl)methanone (JNJ 54166060), a Small Molecule Antagonist of the P2X7 receptor.

J Med Chem 2016 09 8;59(18):8535-48. Epub 2016 Sep 8.

Janssen Pharmaceutical Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121 United States.

The synthesis and SAR of a series of 4,5,6,7-tetrahydro-imidazo[4,5-c]pyridine P2X7 antagonists are described. Addressing P2X7 affinity and liver microsomal stability issues encountered with this template afforded methyl substituted 4,5,6,7-tetrahydro-imidazo[4,5-c]pyridines ultimately leading to the identification of 1 (JNJ 54166060). 1 is a potent P2X7 antagonist with an ED50 = 2.3 mg/kg in rats, high oral bioavailability and low-moderate clearance in preclinical species, acceptable safety margins in rats, and a predicted human dose of 120 mg of QD. Additionally, 1 possesses a unique CYP profile and was found to be a regioselective inhibitor of midazolam CYP3A metabolism.
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http://dx.doi.org/10.1021/acs.jmedchem.6b00989DOI Listing
September 2016

Reply to "A Comment on 'Discovery and Characterization of AMPA Receptor Modulators Selective for TARP-γ8'".

J Pharmacol Exp Ther 2016 09;358(3):527

Janssen Research & Development, LLC, Neuroscience Therapeutic Area, San Diego, California.

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http://dx.doi.org/10.1124/jpet.116.234815DOI Listing
September 2016

The evolution of P2X7 antagonists with a focus on CNS indications.

Bioorg Med Chem Lett 2016 08 30;26(16):3838-45. Epub 2016 Jun 30.

Janssen Pharmaceutical Research & Development L.L.C., 3210 Merryfield Row, San Diego, CA 92121, United States.

The P2X7 receptor is an ATP-gated nonselective cation channel that has been linked to a number of inflammatory diseases. Activation of the P2X7 receptor by elevated levels of ATP results in the release of proinflammatory cytokines and elevated levels of these cytokines has been associated with a variety of disease states. A number of research groups in both industry and academia have explored the identification of P2X7R antagonists as therapeutic agents. Much of this early effort focused on the treatment of diseases related to peripheral inflammation and resulted in several clinical candidates, none of which were advanced to market. The emerging role of the P2X7 receptor in neuroinflammation and related diseases has resulted in a shift in medicinal chemistry efforts toward the development of centrally penetrant antagonists. This review will highlight the biology supporting the role of P2X7 in diseases related to neuroinflammation and review the recent medicinal chemistry efforts to identify centrally penetrant antagonists.
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http://dx.doi.org/10.1016/j.bmcl.2016.06.048DOI Listing
August 2016

Discovery and Characterization of AMPA Receptor Modulators Selective for TARP-γ8.

J Pharmacol Exp Ther 2016 May 17;357(2):394-414. Epub 2016 Mar 17.

Janssen Research and Development, LLC, Neuroscience Therapeutic Area, San Diego, California (M.P.M., N.W., S.R., M.K.A., B.M.S., C.L., B.L., R.M.W., J.A.M., C.D., S.Y., A.D.W., N.I.C., T.W.L.); and Janssen Research and Development, a Division of Janssen Pharmaceutica NV, Neuroscience Therapeutic Area, Beerse, Belgium (L.V.D., T.S.).

Members of the α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionic acid (AMPA) subtype of ionotropic glutamate receptors mediate the majority of fast synaptic transmission within the mammalian brain and spinal cord, representing attractive targets for therapeutic intervention. Here, we describe novel AMPA receptor modulators that require the presence of the accessory protein CACNG8, also known as transmembrane AMPA receptor regulatory protein γ8 (TARP-γ8). Using calcium flux, radioligand binding, and electrophysiological assays of wild-type and mutant forms of TARP-γ8, we demonstrate that these compounds possess a novel mechanism of action consistent with a partial disruption of the interaction between the TARP and the pore-forming subunit of the channel. One of the molecules, 5-[2-chloro-6-(trifluoromethoxy)phenyl]-1,3-dihydrobenzimidazol-2-one (JNJ-55511118), had excellent pharmacokinetic properties and achieved high receptor occupancy following oral administration. This molecule showed strong, dose-dependent inhibition of neurotransmission within the hippocampus, and a strong anticonvulsant effect. At high levels of receptor occupancy in rodent in vivo models, JNJ-55511118 showed a strong reduction in certain bands on electroencephalogram, transient hyperlocomotion, no motor impairment on rotarod, and a mild impairment in learning and memory. JNJ-55511118 is a novel tool for reversible AMPA receptor inhibition, particularly within the hippocampus, with potential therapeutic utility as an anticonvulsant or neuroprotectant. The existence of a molecule with this mechanism of action demonstrates the possibility of pharmacological targeting of accessory proteins, increasing the potential number of druggable targets.
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http://dx.doi.org/10.1124/jpet.115.231712DOI Listing
May 2016

Preclinical characterization of substituted 6,7-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one P2X7 receptor antagonists.

Bioorg Med Chem Lett 2016 Jan 17;26(2):257-261. Epub 2015 Dec 17.

Janssen Pharmaceutical Research & Development L.L.C., 3210 Merryfield Row, San Diego, CA 92121, United States.

The synthesis, SAR, and preclinical characterization of a series of substituted 6,7-dihydro[1,2,4]triazolo[4,3]pyrazin-8(5H)-one P2X7 receptor antagonists are described. Optimized leads from this series comprise some of the most potent human P2X7R antagonists reported to date (IC50s<1nM). They also exhibit sufficient potency and oral bioavailability in rat to enable extensive in vivo profiling. Although many of the disclosed compounds are peripherally restricted, compound 11d is brain penetrant and upon oral administration demonstrated dose-dependent target engagement in rat hippocampus as determined by ex vivo receptor occupancy with radiotracer 5 (ED50=0.8mg/kg).
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http://dx.doi.org/10.1016/j.bmcl.2015.12.052DOI Listing
January 2016

Allyl-Assisted, Cu(I)-Catalyzed Azide-Alkyne Cycloaddition/Allylation Reaction: Assembly of the [1,2,3]Triazolo-4,5,6,7-tetrahydropyridine Core Structure.

J Org Chem 2015 Nov 20;80(21):11003-12. Epub 2015 Oct 20.

Janssen Research & Development LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

We report a Cu(I)-catalyzed azide-alkyne-allyl halide three-component reaction for a one-pot synthesis of 1,4-disubstituted 5-allyl-1,2,3-triazoles. The allyl moiety provides not only the electrophile but also a coordinating ligand to Cu, which is essential for the reaction to occur under mild conditions. A concise synthesis of a potential drug candidate 1 is realized based on this key reaction.
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http://dx.doi.org/10.1021/acs.joc.5b02174DOI Listing
November 2015

Synthesis, SAR, and Pharmacological Characterization of Brain Penetrant P2X7 Receptor Antagonists.

ACS Med Chem Lett 2015 Jun 24;6(6):671-6. Epub 2015 Apr 24.

Janssen Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

We describe the synthesis and SAR of 1,2,3-triazolopiperidines as a novel series of potent, brain penetrant P2X7 antagonists. Initial efforts yielded a series of potent human P2X7R antagonists with moderate to weak rodent potency, some CYP inhibition, poor metabolic stability, and low solubility. Further work in this series, which focused on the SAR of the N-linked heterocycle, not only increased the potency at the human P2X7R but also provided compounds with good potency at the rat P2X7R. These efforts eventually delivered a potent rat and human P2X7R antagonist with good physicochemical properties, an excellent pharmacokinetic profile, good partitioning into the CNS, and demonstrated in vivo target engagement after oral dosing.
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http://dx.doi.org/10.1021/acsmedchemlett.5b00089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4468405PMC
June 2015

Functional Profiling of 2-Aminopyrimidine Histamine H4 Receptor Modulators.

J Med Chem 2015 Sep 3;58(18):7119-27. Epub 2015 Jun 3.

Janssen Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

Histamine is an important endogenous signaling molecule that is involved in a number of physiological processes including allergic reactions, gastric acid secretion, neurotransmitter release, and inflammation. The biological effects of histamine are mediated by four histamine receptors with distinct functions and distribution profiles (H1-H4). The most recently discovered histamine receptor (H4) has emerged as a promising drug target for treating inflammatory diseases. A detailed understanding of the role of the H4 receptor in human disease remains elusive, in part because low sequence similarity between the human and rodent H4 receptors complicates the translation of preclinical pharmacology to humans. This review provides an overview of H4 drug discovery programs that have studied cross-species structure-activity relationships, with a focus on the functional profiling of the 2-aminopyrimidine chemotype that has advanced to the clinic for allergy, atopic dermatitis, asthma, and rheumatoid arthritis.
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http://dx.doi.org/10.1021/acs.jmedchem.5b00516DOI Listing
September 2015

Diaminopyrimidines, diaminopyridines and diaminopyridazines as histamine H4 receptor modulators.

Bioorg Med Chem Lett 2015 Feb 23;25(4):956-9. Epub 2014 Dec 23.

Janssen Pharmaceutical Research & Development, LLC, 3210 Merryfield Row, San Diego, CA 92121, United States.

Previously disclosed H4 receptor modulators, the triamino substituted pyridines and pyrimidines, contain a free primary amino (-NH2) group. In this Letter we demonstrate that an exocyclic amine (NH2) is not needed to maintain affinity, and also show a significant divergence in the SAR of the pendant diamine component. These des-NH2 azacycles also show a distinct functional spectrum, that appears to be influenced by the diamine component; in the case of the 1,3-amino pyrimidines, the preferred diamine is the amino pyrrolidine instead of the more common piperazines. Finally, we introduce 3,5-diamino pyridazines as novel histamine H4 antagonists.
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http://dx.doi.org/10.1016/j.bmcl.2014.12.027DOI Listing
February 2015

The effect of pK(a) on pyrimidine/pyridine-derived histamine H4 ligands.

Bioorg Med Chem Lett 2014 Dec 13;24(23):5489-92. Epub 2014 Oct 13.

Janssen Pharmaceutical Research & Development, LLC, 3210 Merryfield Row, San Diego, CA 92121, United States.

During the course of our efforts toward the discovery of human histamine H4 antagonists from a series of 2-aminiopyrimidines, it was noted that a 6-trifluoromethyl group dramatically reduced affinity of the series toward the histamine H4 receptor. This observation was further investigated by synthesizing a series of ligands that varied in pKa of the pyrimidine derived H4 ligands by over five orders of magnitude and the effect on histamine H4 affinity. This trend was then extended to the discovery of C-linked piperidinyl-2-amino pyridines as histamine H4 receptor antagonists.
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http://dx.doi.org/10.1016/j.bmcl.2014.10.013DOI Listing
December 2014

Discovery and SAR of 6-alkyl-2,4-diaminopyrimidines as histamine H₄ receptor antagonists.

J Med Chem 2014 Mar 21;57(6):2429-39. Epub 2014 Feb 21.

Janssen Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

This report discloses the discovery and SAR of a series of 6-alkyl-2-aminopyrimidine derived histamine H4 antagonists that led to the development of JNJ 39758979, which has been studied in phase II clinical trials in asthma and atopic dermatitis. Building on our SAR studies of saturated derivatives from the indole carboxamide series, typified by JNJ 7777120, and incorporating knowledge from the tricyclic pyrimidines led us to the 6-alkyl-2,4-diaminopyrimidine series. A focused medicinal chemistry effort delivered several 6-alkyl-2,4-diaminopyrimidines that behaved as antagonists at both the human and rodent H4 receptor. Further optimization led to a panel of antagonists that were profiled in animal models of inflammatory disease. On the basis of the preclinical profile and efficacy in several animal models, JNJ 39758979 was selected as a clinical candidate; however, further development was halted during phase II because of the observation of drug-induced agranulocytosis (DIAG) in two subjects.
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http://dx.doi.org/10.1021/jm401727mDOI Listing
March 2014

Tricyclic aminopyrimidine histamine H4 receptor antagonists.

Bioorg Med Chem Lett 2011 Nov 19;21(21):6577-81. Epub 2011 Aug 19.

Johnson & Johnson Pharmaceutical Research & Development, LLC 3210 Merryfield Row, San Diego, CA 92121, USA.

This report discloses the development of a series of tricyclic histamine H(4) receptor antagonists. Starting with a low nanomolar benzofuranopyrimidine HTS hit devoid of pharmaceutically acceptable properties, we navigated issues with metabolism and solubility to furnish a potent, stable and water soluble tricyclic histamine H(4) receptor antagonist with desirable physiochemical parameters which demonstrated efficacy a mouse ova model.
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http://dx.doi.org/10.1016/j.bmcl.2011.08.014DOI Listing
November 2011

Triamino pyrimidines and pyridines as histamine H(4) receptor modulators.

Bioorg Med Chem Lett 2011 May 30;21(10):3113-6. Epub 2011 Mar 30.

Johnson & Johnson Pharmaceutical Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.

Two series of triamino pyrimidines and a series of triamino pyridines have been synthesized and their structure-activity relationships evaluated for activity at the H(4) receptor in competitive binding and functional assays. Small structural changes in these three hetereoaromatic cores influenced the functional activity of these compounds.
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http://dx.doi.org/10.1016/j.bmcl.2011.03.017DOI Listing
May 2011

Agonist/antagonist modulation in a series of 2-aryl benzimidazole H4 receptor ligands.

Bioorg Med Chem Lett 2010 Jun 11;20(11):3367-71. Epub 2010 Apr 11.

Johnson & Johnson Pharmaceutical Research & Development, L.L.C, 3210 Merryfield Row, San Diego, CA 92121, USA.

The present work details the transformation of a series of human histamine H(4) agonists into potent functional antagonists. Replacement of the aminopyrrolidine diamine functionality with a 5,6-fused pyrrolopiperidine ring system led to an antagonist. The dissection of this fused diamine led to the eventual replacement with heterocycles. The incorporation of histamine as the terminal amine led to a very potent and selective histamine H(4) agonist; whereas incorporation of the constrained histamine analog, spinacamine, modulated the functional activity to give a partial agonist. In two separate series, we demonstrate that constraining the terminal amino portion modulated the spectrum of functional activity of histamine H(4) ligands.
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http://dx.doi.org/10.1016/j.bmcl.2010.04.017DOI Listing
June 2010

Identification of a potent, selective, and orally active leukotriene a4 hydrolase inhibitor with anti-inflammatory activity.

J Med Chem 2008 Jul 28;51(14):4150-69. Epub 2008 Jun 28.

Johnson & Johnson Pharmaceutical Research & Development, L.L.C., 3210 Merryfield Row, San Diego, California 92121, USA.

LTA 4H is a ubiquitously distributed 69 kDa zinc-containing cytosolic enzyme with both hydrolase and aminopeptidase activity. As a hydrolase, LTA 4H stereospecifically catalyzes the transformation of the unstable epoxide LTA 4 to the diol LTB 4, a potent chemoattractant and activator of neutrophils and a chemoattractant of eosinophils, macrophages, mast cells, and T cells. Inhibiting the formation of LTB 4 is expected to be beneficial in the treatment of inflammatory diseases such as inflammatory bowel disease (IBD), asthma, and atherosclerosis. We developed a pharmacophore model using a known inhibitor manually docked into the active site of LTA 4H to identify a subset of compounds for screening. From this work we identified a series of benzoxazole, benzthiazole, and benzimidazole inhibitors. SAR studies resulted in the identification of several potent inhibitors with an appropriate cross-reactivity profile and excellent PK/PD properties. Our efforts focused on further profiling JNJ 27265732, which showed encouraging efficacy in a disease model relevant to IBD.
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http://dx.doi.org/10.1021/jm701575kDOI Listing
July 2008

Total synthesis of formamicin.

J Am Chem Soc 2004 Aug;126(30):9307-17

Department of Chemistry, University of Michigan, 930 North University, Ann Arbor, Michigan 48109, USA.

The enantioselective total synthesis of the cytotoxic plecomacrolide natural product formamicin (1) is described. Key aspects of this synthesis include the efficient transacetalation reactions of MOM ethers 28 and 38 to form the seven-membered formyl acetals 29 and 39, a late-stage Suzuki cross-coupling reaction of the highly functionalized vinyl boronic acid 6 and vinyl iodide 7, a highly beta-selective glycosidation reaction of beta-hydroxy ketone 4 with 2,6-dideoxy-2-iodoglucopyranosyl fluoride 3, and the global desilylation of penultimate intermediate 77 mediated by in situ generated Et(3)N.2HF.
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http://dx.doi.org/10.1021/ja048493lDOI Listing
August 2004

Total synthesis of the formamicin aglycon, formamicinone.

Org Lett 2003 Feb;5(3):377-9

Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.

[structure: see text] The total synthesis of formamicinone (2), the aglycone of formamicin (1), has been accomplished via the late-stage Suzuki cross-coupling of fragments 5 and 6, the macrolactonization of seco ester 14, and the Mukaiyama aldol reaction of aldehyde 3 and methyl ketone 4. An efficient and highly stereoselective second generation synthesis of vinyl iodide 6 is also described.
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http://dx.doi.org/10.1021/ol027569kDOI Listing
February 2003

Total synthesis of (-)-bafilomycin A(1).

J Am Chem Soc 2002 Jun;124(24):6981-90

Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.

A highly stereoselective total synthesis of (-)-bafilomycin A(1), the naturally occurring enantiomer of this potent vacuolar ATPase inhibitor, is described. The synthesis features the highly stereoselective aldol reaction of methyl ketone 8b and aldehyde 60c and a Suzuki cross-coupling reaction of the highly functionalized advanced intermediates 12 and 39. Vinyl iodide 12 was synthesized by a 14-step sequence starting from the readily available beta-alkoxy aldehyde 14, while the vinylboronic acid component 39 was synthesized by a nine-step sequence from beta-hydroxy-alpha-methyl butyrate 44 via a sequence involving the alpha-methoxypropargylation of chiral aldehyde 49 with the alpha-methoxypropargylstannane reagent 54. Syntheses of fragments 12 and 39 also feature diastereoselective double asymmetric crotylboration reactions to set several of the critical stereocenters. The Suzuki cross-coupling of 12 and 39 provided seco ester 40, which following conversion to the seco acid underwent smooth macrolactonization to give 41. The success of the macrocyclization required that C(7)-OH be unprotected. The Mukaiyama aldol reaction between aldehyde 60c and the TMS enol ether generated from 8b provided aldol 65 with high diastereoselectivity. Finally, all silicon protecting groups were removed by treatment of the penultimate intermediate 65 with TAS-F (tris(dimethylamino)sulfonium difluorotrimethylsilicate), thereby completing the total synthesis of (-)-bafilomycin A(1).
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http://dx.doi.org/10.1021/ja017885eDOI Listing
June 2002