1
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Kang G, Xiao LJ, Hesp KD, Huh CW, Lian Y, Richardson P, Schmitt DC, Hong K, Yu JQ. Synthesis of Highly Substituted Aminotetrahydropyrans Enabled by Stereospecific Multivector C-H Functionalization. Org Lett 2024; 26:2729-2732. [PMID: 37294050 DOI: 10.1021/acs.orglett.3c01439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Highly substituted aminotetrahydropyrans were synthesized via sequential C-H functionalizations. The process was initiated with a Pd(II)-catalyzed stereoselective γ-methylene C-H arylation of aminotetrahydropyran, followed by α-alkylation or arylation of the corresponding primary amine. The initial γ-C-H (hetero)arylation was compatible with a range of aryl iodides containing various substituents and provided the corresponding products in moderate to good yields. The subsequent α-alkylation or arylation of the isolated arylated products proceeded with high diastereoselectivity to afford value-added disubstituted aminotetrahydropyrans.
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Affiliation(s)
- Guowei Kang
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Li-Jun Xiao
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Kevin D Hesp
- Treeline Biosciences, 500 Arsenal St, second Floor, Watertown, Massachusetts 02472, United States
| | - Chan Woo Huh
- Medicine Design, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Yajing Lian
- Medicine Design, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Paul Richardson
- Medicine Design, Pfizer Inc., San Diego, California 92121, United States
| | - Daniel C Schmitt
- Medicine Design, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Kai Hong
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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2
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Zhang B, He J, Gao Y, Levy L, Oderinde MS, Palkowitz MD, Dhar TGM, Mandler MD, Collins MR, Schmitt DC, Bolduc PN, Chen T, Clementson S, Petersen NN, Laudadio G, Bi C, Kawamata Y, Baran PS. Complex molecule synthesis by electrocatalytic decarboxylative cross-coupling. Nature 2023; 623:745-751. [PMID: 37788684 PMCID: PMC10754231 DOI: 10.1038/s41586-023-06677-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 09/26/2023] [Indexed: 10/05/2023]
Abstract
Modern retrosynthetic analysis in organic chemistry is based on the principle of polar relationships between functional groups to guide the design of synthetic routes1. This method, termed polar retrosynthetic analysis, assigns partial positive (electrophilic) or negative (nucleophilic) charges to constituent functional groups in complex molecules followed by disconnecting bonds between opposing charges2-4. Although this approach forms the basis of undergraduate curriculum in organic chemistry5 and strategic applications of most synthetic methods6, the implementation often requires a long list of ancillary considerations to mitigate chemoselectivity and oxidation state issues involving protecting groups and precise reaction choreography3,4,7. Here we report a radical-based Ni/Ag-electrocatalytic cross-coupling of substituted carboxylic acids, thereby enabling an intuitive and modular approach to accessing complex molecular architectures. This new method relies on a key silver additive that forms an active Ag nanoparticle-coated electrode surface8,9 in situ along with carefully chosen ligands that modulate the reactivity of Ni. Through judicious choice of conditions and ligands, the cross-couplings can be rendered highly diastereoselective. To demonstrate the simplifying power of these reactions, concise syntheses of 14 natural products and two medicinally relevant molecules were completed.
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Affiliation(s)
- Benxiang Zhang
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Jiayan He
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Yang Gao
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Laura Levy
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Martins S Oderinde
- Department of Discovery Synthesis, Bristol Myers Squibb Research & Early Development, Princeton, NJ, USA
| | - Maximilian D Palkowitz
- Small Molecule Drug Discovery, Bristol Myers Squibb Research & Early Development, Cambridge, MA, USA
| | - T G Murali Dhar
- Bristol Myers Squibb Research & Early Development, Princeton, NJ, USA
| | - Michael D Mandler
- Bristol Myers Squibb Research & Early Development, Princeton, NJ, USA
| | - Michael R Collins
- Oncology Medicinal Chemistry Department, Pfizer Pharmaceuticals, San Diego, CA, USA
| | - Daniel C Schmitt
- Medicine Design, Pfizer Worldwide Research and Development, Groton, CT, USA
- Discovery Chemistry Research and Technologies, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | | | | | | | | | | | - Cheng Bi
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Yu Kawamata
- Department of Chemistry, Scripps Research, La Jolla, CA, USA.
| | - Phil S Baran
- Department of Chemistry, Scripps Research, La Jolla, CA, USA.
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3
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Conn EL, Perry MA, Shi K, Wang G, Hoy S, Sach NW, Qi W, Qu L, Gao Y, Xu Y, Schmitt DC. Identification of parallel medicinal chemistry protocols to expand branched amine design space. Org Biomol Chem 2022; 20:3747-3754. [PMID: 35448901 DOI: 10.1039/d2ob00155a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
α-Branched heteroaryl amines are prevalent motifs in drugs and are typically prepared through C-N bond formation. In contrast, C-C bond-forming approaches to branched amines may dramatically expand available chemical space but are rarely pursued in parallel format due to a lack of established library protocols. Methods for the synthesis of α-branched heteroaryl amines via aldimine addition have been evaluated for compatibility with parallel synthesis. In situ activation of aliphatic carboxylic acids as redox-active esters enables Zn-mediated decarboxylative radical imine addition to access aliphatic-branched heterobenzylic amines. In situ activation of (hetero)aryl bromides via Li-halogen exchange enables heteroaryl-lithium addition to imines to access (hetero)benzhydryl amines. Condensation of heteroaryl amines with heteroaryl aldehydes provides aldimines which may be intercepted with aryl Grignard reagents to provide modular access to (hetero)benzhydryl amines. These protocols minimize synthetic step count and maximize accessible design space, enhancing access to α-branched heteroaryl amines for medicinal chemistry.
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Affiliation(s)
- Edward L Conn
- Medicine Design, Pfizer Worldwide Research, Development and Medical, Groton, Connecticut 06340, USA.
| | - Matthew A Perry
- Medicine Design, Pfizer Worldwide Research, Development and Medical, Groton, Connecticut 06340, USA.
| | - Kecheng Shi
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Guotao Wang
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Susan Hoy
- Medicine Design, Pfizer Worldwide Research, Development and Medical, Groton, Connecticut 06340, USA.
| | - Neal W Sach
- Medicine Design, Pfizer Worldwide Research, Development and Medical, 10770 Science Center Drive, San Diego, California 92121, USA
| | - Wenying Qi
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Liqiang Qu
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Yu Gao
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Yan Xu
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Daniel C Schmitt
- Medicine Design, Pfizer Worldwide Research, Development and Medical, Groton, Connecticut 06340, USA.
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4
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Hernández‐Lladó P, Garrec K, Schmitt DC, Burton JW. Transition Metal‐Free, Visible Light‐Mediated Radical Cyclisation of Malonyl Radicals onto 5‐Ring Heteroaromatics. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202101451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Pol Hernández‐Lladó
- Department of Chemistry Chemistry Research Laboratory University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Kilian Garrec
- Department of Chemistry Chemistry Research Laboratory University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Daniel C. Schmitt
- Medicine Design Pfizer Worldwide Research Development and Medical Groton Connecticut 06340 United States
| | - Jonathan W. Burton
- Department of Chemistry Chemistry Research Laboratory University of Oxford Mansfield Road Oxford OX1 3TA UK
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5
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Rojas JJ, Croft RA, Sterling AJ, Briggs EL, Antermite D, Schmitt DC, Blagojevic L, Haycock P, White AJP, Duarte F, Choi C, Mousseau JJ, Bull JA. Amino-oxetanes as amide isosteres by an alternative defluorosulfonylative coupling of sulfonyl fluorides. Nat Chem 2022; 14:160-169. [PMID: 35087220 DOI: 10.1038/s41557-021-00856-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 11/11/2021] [Indexed: 01/10/2023]
Abstract
Bioisosteres provide valuable design elements that medicinal chemists can use to adjust the structural and pharmacokinetic characteristics of bioactive compounds towards viable drug candidates. Aryl oxetane amines offer exciting potential as bioisosteres for benzamides-extremely common pharmacophores-but are rarely examined due to the lack of available synthetic methods. Here we describe a class of reactions for sulfonyl fluorides to form amino-oxetanes by an alternative pathway to the established SuFEx (sulfonyl-fluoride exchange) click reactivity. A defluorosulfonylation forms planar oxetane carbocations simply on warming. This disconnection, comparable to a typical amidation, will allow the application of vast existing amine libraries. The reaction is tolerant to a wide range of polar functionalities and is suitable for array formats. Ten oxetane analogues of bioactive benzamides and marketed drugs are prepared. Kinetic and computational studies support the formation of an oxetane carbocation as the rate-determining step, followed by a chemoselective nucleophile coupling step.
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Affiliation(s)
- Juan J Rojas
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Rosemary A Croft
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Alistair J Sterling
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Edward L Briggs
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Daniele Antermite
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Daniel C Schmitt
- Pfizer Worldwide Research, Development and Medical, Groton, CT, USA
| | - Luka Blagojevic
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Peter Haycock
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Andrew J P White
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Fernanda Duarte
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Chulho Choi
- Pfizer Worldwide Research, Development and Medical, Groton, CT, USA
| | - James J Mousseau
- Pfizer Worldwide Research, Development and Medical, Groton, CT, USA
| | - James A Bull
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK.
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6
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Saint-Denis TG, Lam NYS, Chekshin N, Richardson PF, Chen JS, Elleraas J, Hesp KD, Schmitt DC, Lian Y, Huh CW, Yu JQ. Mechanistic study of enantioselective Pd-catalyzed C(sp 3)-H activation of thioethers involving two distinct stereomodels. ACS Catal 2021; 11:9738-9753. [PMID: 35572380 DOI: 10.1021/acscatal.1c02808] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enantioselective C(sp3)-H activation has gained considerable attention from the synthetic chemistry community. Despite the intense interest in these reactions, the mechanisms responsible for enantioselection are still vague. In the course of the development of aryl thioether-directed C(sp3)-H arylation, we noticed extreme variation in sensitivity of two substrate classes to substituent effects of ligands and directing groups: whereas 3-pentyl sulfides (prochiral α-center) responded positively to substitution on ligands and directing groups, isobutyl sulfides (prochiral β-center) were entirely insensitive. Quantitative structure selectivity relationship (QSSR) analyses of directing group and ligand substitution and the development of a new class of mono-N-acetyl protected amino anilamide (MPAAn) ligands led to high enantiomeric ratios (up to 99:1) for thioether-directed C(sp3)-H arylation. Key to the realization of this method was the exploitation of transient chirality at sulfur, which relays stereochemical information from the ligand backbone to enantiotopic carbons of the substrate in a rate- and enantio-determining cyclometallation deprotonation. The absolute stereochemistry of the products for these two substrates were revealed to be opposite. DFT evaluation of all possible diastereomeric transition states confirmed initial premises that guided rational ligand and directing group design. The implications of this study will assist in the further development of enantioselective C(sp3)-H activation, namely by highlighting the non-innocence of directing groups, distal steric influences, and the delicate interplay between steric Pauli repulsion and London dispersion in enantioinduction.
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Affiliation(s)
| | - Nelson Y S Lam
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037
| | - Nikita Chekshin
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037
| | - Paul F Richardson
- Oncology Medicinal Chemistry, Pfizer Global Research and Development, San Diego, CA 92121
| | - Jason S Chen
- Automated Synthesis Facility, The Scripps Research Institute, La Jolla, CA 92037
| | - Jeff Elleraas
- Oncology Medicinal Chemistry, Pfizer Global Research and Development, San Diego, CA 92121
| | - Kevin D Hesp
- Medicine Design, Pfizer Global Research and Development, Groton, CT 06340
| | - Daniel C Schmitt
- Medicine Design, Pfizer Global Research and Development, Groton, CT 06340
| | - Yajing Lian
- Medicine Design, Pfizer Global Research and Development, Groton, CT 06340
| | - Chan Woo Huh
- Medicine Design, Pfizer Global Research and Development, Groton, CT 06340
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037
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7
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Abstract
An efficient approach to the parallel synthesis of benzimidazoles from anilines is described. Library approaches to vary the N1 and C2 vectors of benzimidazoles are well established; however, C4-C7 variation has traditionally relied on 1,2-dianiline building blocks, providing limited chemical space coverage. We have developed an amidine formation/oxidative cyclization sequence that enables anilines as a diversity set for benzimidazole C4-C7 SAR generation in parallel format. The amidine annulation was achieved using PIDA or Cu-mediated oxidation to access both N-H and N-alkyl benzimidazoles. This library protocol has now been utilized for analog production in four medicinal chemistry projects. Additionally, the synthesis of aza-benzimidazoles from aminopyridines was achieved via an analogous sequence.
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Affiliation(s)
- Eric P. Arnold
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Prolay K. Mondal
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Daniel C. Schmitt
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
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8
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Ni S, Padial NM, Kingston C, Vantourout JC, Schmitt DC, Edwards JT, Kruszyk MM, Merchant RR, Mykhailiuk PK, Sanchez BB, Yang S, Perry MA, Gallego GM, Mousseau JJ, Collins MR, Cherney RJ, Lebed PS, Chen JS, Qin T, Baran PS. A Radical Approach to Anionic Chemistry: Synthesis of Ketones, Alcohols, and Amines. J Am Chem Soc 2019; 141:6726-6739. [PMID: 30943023 DOI: 10.1021/jacs.9b02238] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Historically accessed through two-electron, anionic chemistry, ketones, alcohols, and amines are of foundational importance to the practice of organic synthesis. After placing this work in proper historical context, this Article reports the development, full scope, and a mechanistic picture for a strikingly different way of forging such functional groups. Thus, carboxylic acids, once converted to redox-active esters (RAEs), can be utilized as formally nucleophilic coupling partners with other carboxylic derivatives (to produce ketones), imines (to produce benzylic amines), or aldehydes (to produce alcohols). The reactions are uniformly mild, operationally simple, and, in the case of ketone synthesis, broad in scope (including several applications to the simplification of synthetic problems and to parallel synthesis). Finally, an extensive mechanistic study of the ketone synthesis is performed to trace the elementary steps of the catalytic cycle and provide the end-user with a clear and understandable rationale for the selectivity, role of additives, and underlying driving forces involved.
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Affiliation(s)
- Shengyang Ni
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Natalia M Padial
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Cian Kingston
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Julien C Vantourout
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Daniel C Schmitt
- Pfizer Medicinal Sciences , Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Jacob T Edwards
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Monika M Kruszyk
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Rohan R Merchant
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Pavel K Mykhailiuk
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States.,Enamine Ltd. , Chervonotkatska 78 , 02094 Kyiv , Ukraine.,Chemistry Department , Taras Shevchenko National University of Kyiv , Volodymyrska 64 , 01601 Kyiv , Ukraine
| | - Brittany B Sanchez
- Automated Synthesis Facility , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Shouliang Yang
- Department of Chemistry , La Jolla Laboratories , Pfizer 10770 Science Center Drive , San Diego , California 92121 , United States
| | - Matthew A Perry
- Pfizer Medicinal Sciences , Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Gary M Gallego
- Department of Chemistry , La Jolla Laboratories , Pfizer 10770 Science Center Drive , San Diego , California 92121 , United States
| | - James J Mousseau
- Pfizer Medicinal Sciences , Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Michael R Collins
- Department of Chemistry , La Jolla Laboratories , Pfizer 10770 Science Center Drive , San Diego , California 92121 , United States
| | - Robert J Cherney
- Research & Development , Bristol-Myers Squibb Company , Rt. 206 & Province Line Road , Princeton , New Jersey 08543 , United States
| | - Pavlo S Lebed
- Enamine Ltd. , Chervonotkatska 78 , 02094 Kyiv , Ukraine.,ChemBioCenter , Taras Shevchenko National University of Kyiv , Volodymyrska 64 , 01601 Kyiv , Ukraine
| | - Jason S Chen
- Automated Synthesis Facility , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Tian Qin
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Phil S Baran
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
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9
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Ni S, Garrido-Castro AF, Merchant RR, de Gruyter JN, Schmitt DC, Mousseau JJ, Gallego GM, Yang S, Collins MR, Qiao JX, Yeung KS, Langley DR, Poss MA, Scola PM, Qin T, Baran PS. A General Amino Acid Synthesis Enabled by Innate Radical Cross-Coupling. Angew Chem Int Ed Engl 2018; 57:14560-14565. [PMID: 30212610 PMCID: PMC6352899 DOI: 10.1002/anie.201809310] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 01/21/2023]
Abstract
The direct union of primary, secondary, and tertiary carboxylic acids with a chiral glyoxylate-derived sulfinimine provides rapid access into a variety of enantiomerically pure α-amino acids (>85 examples). Characterized by operational simplicity, this radical-based reaction enables the modular assembly of exotic α-amino acids, including both unprecedented structures and those of established industrial value. The described method performs well in high-throughput library synthesis, and has already been implemented in three distinct medicinal chemistry campaigns.
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Affiliation(s)
- Shengyang Ni
- Scripps Research, North Torrey Pines Road, La Jolla, CA, 92037, USA
| | | | - Rohan R Merchant
- Scripps Research, North Torrey Pines Road, La Jolla, CA, 92037, USA
| | | | - Daniel C Schmitt
- Pfizer Medicinal Sciences, Eastern Point Road, Groton, CT, 06340, USA
| | - James J Mousseau
- Pfizer Medicinal Sciences, Eastern Point Road, Groton, CT, 06340, USA
| | - Gary M Gallego
- Department of Chemistry, La Jolla Laboratories, Pfizer, 10770 Science Center Drive, San Diego, CA, 92121, USA
| | - Shouliang Yang
- Department of Chemistry, La Jolla Laboratories, Pfizer, 10770 Science Center Drive, San Diego, CA, 92121, USA
| | - Michael R Collins
- Department of Chemistry, La Jolla Laboratories, Pfizer, 10770 Science Center Drive, San Diego, CA, 92121, USA
| | - Jennifer X Qiao
- Department of Discovery Chemistry, Bristol-Myers Squibb Company, Research and Development, P.O. Box 4000, Princeton, NJ, 08543, USA
| | - Kap-Sun Yeung
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, CT, 06492, USA
| | - David R Langley
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, CT, 06492, USA
| | - Michael A Poss
- Department of Discovery Chemistry, Bristol-Myers Squibb Company, Research and Development, P.O. Box 4000, Princeton, NJ, 08543, USA
| | - Paul M Scola
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, CT, 06492, USA
| | - Tian Qin
- Scripps Research, North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Phil S Baran
- Scripps Research, North Torrey Pines Road, La Jolla, CA, 92037, USA
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10
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Ni S, Garrido-Castro AF, Merchant RR, de Gruyter JN, Schmitt DC, Mousseau JJ, Gallego GM, Yang S, Collins MR, Qiao JX, Yeung KS, Langley DR, Poss MA, Scola PM, Qin T, Baran PS. A General Amino Acid Synthesis Enabled by Innate Radical Cross-Coupling. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809310] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Shengyang Ni
- Scripps Research; North Torrey Pines Road La Jolla CA 92037 USA
| | | | | | | | | | | | - Gary M. Gallego
- Department of Chemistry; La Jolla Laboratories; Pfizer; 10770 Science Center Drive San Diego CA 92121 USA
| | - Shouliang Yang
- Department of Chemistry; La Jolla Laboratories; Pfizer; 10770 Science Center Drive San Diego CA 92121 USA
| | - Michael R. Collins
- Department of Chemistry; La Jolla Laboratories; Pfizer; 10770 Science Center Drive San Diego CA 92121 USA
| | - Jennifer X. Qiao
- Department of Discovery Chemistry; Bristol-Myers Squibb Company; Research and Development; P.O. Box 4000 Princeton NJ 08543 USA
| | - Kap-Sun Yeung
- Department of Discovery Chemistry; Bristol-Myers Squibb Research and Development; 5 Research Parkway Wallingford CT 06492 USA
| | - David R. Langley
- Department of Discovery Chemistry; Bristol-Myers Squibb Research and Development; 5 Research Parkway Wallingford CT 06492 USA
| | - Michael A. Poss
- Department of Discovery Chemistry; Bristol-Myers Squibb Company; Research and Development; P.O. Box 4000 Princeton NJ 08543 USA
| | - Paul M. Scola
- Department of Discovery Chemistry; Bristol-Myers Squibb Research and Development; 5 Research Parkway Wallingford CT 06492 USA
| | - Tian Qin
- Scripps Research; North Torrey Pines Road La Jolla CA 92037 USA
| | - Phil S. Baran
- Scripps Research; North Torrey Pines Road La Jolla CA 92037 USA
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11
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Abstract
A modular, two-pot assembly of 7-arylpyrazolo[1,5- a]pyrimidones from aryl/heteroaryl halides and aminopyrazoles in library format was developed. Sonogashira coupling of aryl bromides with triethyl orthopropiolate, followed by in situ orthoester hydrolysis, provides access to β-aryl ynoates, which undergo regioselective cyclocondensation with aminopyrazoles. The ability to vary the C7 vector of 7-arylpyrazolo[1,5- a]pyrimidones in two steps using readily available (hetero)aryl halides significantly enhances synthetic access to this challenging vector.
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Affiliation(s)
- Daniel C. Schmitt
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Nootaree Niljianskul
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Neal W. Sach
- Department of Chemistry, La Jolla Laboratories, Pfizer Inc., 10770 Science Center Drive, San Diego, California 92121, United States
| | - John I. Trujillo
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
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12
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Hall J, Ralph EC, Shanker S, Wang H, Byrnes LJ, Horst R, Wong J, Brault A, Dumlao D, Smith JF, Dakin LA, Schmitt DC, Trujillo J, Vincent F, Griffor M, Aulabaugh AE. The catalytic mechanism of cyclic GMP-AMP synthase (cGAS) and implications for innate immunity and inhibition. Protein Sci 2017; 26:2367-2380. [PMID: 28940468 PMCID: PMC5699495 DOI: 10.1002/pro.3304] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/12/2017] [Accepted: 09/18/2017] [Indexed: 01/05/2023]
Abstract
Cyclic GMP-AMP synthase (cGAS) is activated by ds-DNA binding to produce the secondary messenger 2',3'-cGAMP. cGAS is an important control point in the innate immune response; dysregulation of the cGAS pathway is linked to autoimmune diseases while targeted stimulation may be of benefit in immunoncology. We report here the structure of cGAS with dinucleotides and small molecule inhibitors, and kinetic studies of the cGAS mechanism. Our structural work supports the understanding of how ds-DNA activates cGAS, suggesting a site for small molecule binders that may cause cGAS activation at physiological ATP concentrations, and an apparent hotspot for inhibitor binding. Mechanistic studies of cGAS provide the first kinetic constants for 2',3'-cGAMP formation, and interestingly, describe a catalytic mechanism where 2',3'-cGAMP may be a minor product of cGAS compared with linear nucleotides.
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Affiliation(s)
- Justin Hall
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Erik C Ralph
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Suman Shanker
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Hong Wang
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Laura J Byrnes
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Reto Horst
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Jimson Wong
- Hit Discovery and Lead Profiling, Pfizer Centers for Therapeutic Innovation (CTI), Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Amy Brault
- Hit Discovery and Lead Profiling, Pfizer Centers for Therapeutic Innovation (CTI), Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Darren Dumlao
- Hit Discovery and Lead Profiling, Pfizer Centers for Therapeutic Innovation (CTI), Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - James F Smith
- Hit Discovery and Lead Profiling, Pfizer Centers for Therapeutic Innovation (CTI), Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Leslie A Dakin
- Worldwide Medicinal Chemistry, Pfizer, 610 Main St, Cambridge, Massachusetts, 02139
| | - Daniel C Schmitt
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - John Trujillo
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Fabien Vincent
- Hit Discovery and Lead Profiling, Pfizer Centers for Therapeutic Innovation (CTI), Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Matt Griffor
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
| | - Ann E Aulabaugh
- Worldwide Medicinal Chemistry, Pfizer, Eastern Point Road, Groton, Connecticut, 06340
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13
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Abstract
1,3-Diols engage in ruthenium-catalyzed hydrogen transfer in the presence of alkyl hydrazines to provide 1,4-disubstituted pyrazoles. Regioselective synthesis of unsymmetrical pyrazoles from β-hydroxy ketones is also described.
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Affiliation(s)
- Daniel C Schmitt
- Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Alexandria P Taylor
- Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Andrew C Flick
- Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Robert E Kyne
- Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
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14
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Dechert-Schmitt AMR, Schmitt DC, Gao X, Itoh T, Krische MJ. Polyketide construction via hydrohydroxyalkylation and related alcohol C-H functionalizations: reinventing the chemistry of carbonyl addition. Nat Prod Rep 2014; 31:504-13. [PMID: 24514754 PMCID: PMC3954971 DOI: 10.1039/c3np70076c] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Despite the longstanding importance of polyketide natural products in human medicine, nearly all commercial polyketide-based drugs are prepared through fermentation or semi-synthesis. The paucity of manufacturing routes involving de novo chemical synthesis reflects the inability of current methods to concisely address the preparation of these complex structures. Direct alcohol C-H bond functionalization via"C-C bond forming transfer hydrogenation" provides a powerful, new means of constructing type I polyketides that bypasses stoichiometric use of chiral auxiliaries, premetallated C-nucleophiles, and discrete alcohol-to-aldehyde redox reactions. Using this emergent technology, total syntheses of 6-deoxyerythronolide B, bryostatin 7, trienomycins A and F, cyanolide A, roxaticin, and formal syntheses of rifamycin S and scytophycin C, were accomplished. These syntheses represent the most concise routes reported to any member of the respective natural product families.
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Affiliation(s)
- Anne-Marie R Dechert-Schmitt
- University of Texas at Austin, Department of Chemistry and Biochemistry, 105 E 24th St., Welch Hall A5300, Austin, TX 78712-1165, USA.
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15
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Schmitt DC, Lee J, Dechert-Schmitt AMR, Yamaguchi E, Krische MJ. Ruthenium catalyzed hydroaminoalkylation of isoprene via transfer hydrogenation: byproduct-free prenylation of hydantoins. Chem Commun (Camb) 2013; 49:6096-8. [PMID: 23722271 DOI: 10.1039/c3cc43463j] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ruthenium catalyst derived from Ru3(CO)12 and triphos [Ph2P(CH2CH2PPh2)2] promotes the direct C-C coupling of isoprene with aryl substituted hydantoins 1a–1f at the diene C4-position to furnish products of n-prenylation 2a–2f. A mechanism involving hydantoin dehydrogenation followed by diene-imine oxidative coupling to furnish a transient aza-ruthencyclopentene is proposed.
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Affiliation(s)
- Daniel C Schmitt
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
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16
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Dechert-Schmitt AMR, Schmitt DC, Krische MJ. Protecting-Group-Free Diastereoselective CC Coupling of 1,3-Glycols and Allyl Acetate through Site-Selective Primary Alcohol Dehydrogenation. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209863] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Dechert-Schmitt AMR, Schmitt DC, Krische MJ. Protecting-group-free diastereoselective C-C coupling of 1,3-glycols and allyl acetate through site-selective primary alcohol dehydrogenation. Angew Chem Int Ed Engl 2013; 52:3195-8. [PMID: 23364927 DOI: 10.1002/anie.201209863] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Indexed: 11/07/2022]
Affiliation(s)
- Anne-Marie R Dechert-Schmitt
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station-A5300, Austin, TX 78712-1167, USA
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18
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Schmitt DC, Dechert-Schmitt AMR, Krische MJ. Iridium-catalyzed allylation of chiral β-stereogenic alcohols: bypassing discrete formation of epimerizable aldehydes. Org Lett 2012; 14:6302-5. [PMID: 23231774 PMCID: PMC3529126 DOI: 10.1021/ol3030692] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cyclometalated π-allyliridium 3,4-dinitro-C,O-benzoate complex modified by (R)- or (S)-Cl,MeO-BIPHEP promotes the transfer hydrogenative coupling of allyl acetate to β-stereogenic alcohols with good to excellent levels of catalyst-directed diastereoselectivity to furnish homoallylic alcohols. Remote electronic effects of the C,O-benzoate of the catalyst play a critical role in suppressing epimerization of the transient α-stereogenic aldehyde.
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Affiliation(s)
- Daniel C. Schmitt
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
| | | | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
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19
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Boyce GR, Greszler SN, Johnson JS, Linghu X, Malinowski JT, Nicewicz DA, Satterfield AD, Schmitt DC, Steward KM. Silyl glyoxylates. Conception and realization of flexible conjunctive reagents for multicomponent coupling. J Org Chem 2012; 77:4503-15. [PMID: 22414181 PMCID: PMC3356452 DOI: 10.1021/jo300184h] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This Perspective describes the discovery and development of silyl glyoxylates, a new family of conjunctive reagents for use in multicomponent coupling reactions. The selection of the nucleophilic and electrophilic components determines whether the silyl glyoxylate reagent will function as a synthetic equivalent to the dipolar glycolic acid synthon, the glyoxylate anion synthon, or the α-keto ester homoenolate synthon. The ability to select for any of these reaction modes has translated to excellent structural diversity in the derived three- and four-component coupling adducts. Preliminary findings on the development of catalytic reactions using these reagents are detailed, as are the design and discovery of new reactions directed toward particular functional group arrays embedded within bioactive natural products.
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Affiliation(s)
- Gregory R. Boyce
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Stephen N. Greszler
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Jeffrey S. Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Xin Linghu
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Justin T. Malinowski
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - David A. Nicewicz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Andrew D. Satterfield
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Daniel C. Schmitt
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Kimberly M. Steward
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
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20
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Abstract
Silyl glyoxylates react with enolates and enones to afford either glycolate aldol or Michael adducts. Product identity is controlled by the countercation associated with the enolate. Reformatsky nucleophiles in the presence of additional Zn(OTf)(2) result in aldol coupling (A), while lithium enolates provide the Michael coupling (B). Deprotonation of the aldol product A with LDA induces equilibration to form the minor diastereomer of Michael product B. This observation suggests that formation of the major diastereomer of Michael product B does not occur via an aldol/retro-aldol/Michael sequence.
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Affiliation(s)
- Daniel C Schmitt
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
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21
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Abstract
Three-component coupling of the lithium enolate of t-BuOAc, silyl glyoxylate, and an α,β-unsaturated ketone enables the rapid construction of the trachyspic acid carbon skeleton. A 3,4-disubstituted isoxazole is utilized to mask the C7/C9 dicarbonyl. New enolsilane/nitrile-oxide cycloadditions enable the preparation of various 3,4-disubstituted isoxazoles that are challenging to access by other means.
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Affiliation(s)
- Daniel C. Schmitt
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290
| | - Leighann Lam
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290
| | - Jeffrey S. Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290
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22
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Anzeneder T, Ailer G, Ohlms U, Schmitt DC, Waldner C. Abstract P4-13-01: Follow-Up in Biobanking — Strategy and Outcomes of Patients’ Tumor Bank of Hope (PATH). Cancer Res 2010. [DOI: 10.1158/0008-5472.sabcs10-p4-13-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Purpose: Breast Cancer Patients established PATH in 2002 to collect tumor sam-ples, blood samples and data at high ethical standards and under uniform SOPs. Since 2004 more then 4500 women and men in Germany gave their informed consent for the collection. In addition, PATH has successfully started to collect follow-up data from all patients, covering both disease and therapy process.
Design: Specimen (tumor, normal tissue, blood serum) are stored in liquid nitrogen tanks (fresh frozen quality) operated by pathologists at seven certified breast cancer centers in Germany. To provide a benefit for the donors, the first aliquot is stored exclusively for the patient. The rest of the material is donated to research purposes. Processing, handling and labelling of the samples is defined in rigid SOPs, accompanied by monitoring. Data regarding clinical findings, tumor-biology and sample processing are collected and centrally managed. In order to annotate the samples follow up started in early 2009. As a patient driven, non-profit organization PATH has a special reliability. Thus, the Foundation is given the right to establish direct contact with any patient that has given informed con-sent. This approach was confirmed by ethics committee, the Bavarian Commission of Data Protection and a university professor of medical law. In order to get the follow-up data, PATH contacts the patient by letter. A structured phone call follows, carried out by female medical students, who are specially trained. The patient is asked to provide details on their individual course of disease. Additionally they are asked about their compliance with therapy. Procedure, data volume and data quality are specified and standardized. If patients could not be reached by call they are asked to complete an additionally mailed questionnaire. As the last source for data PATH will try to get data from tumor registers. In case of re-currence the data obtained from the patients is validated by check-ups with medical reports from the practitioners.
Results: By May 2010 more than 4500 patients gave informed consent. 4042 cases have been documented in their entirety in the data base. 75% have stored a patient's tumor specimen and 61% a research tumor sample in the bio bank. As many patients have multiple samples there is a total of 4080 tumor specimen, 9029 blood serum and 4075 normal tissue aliquots for research purposes. 2253 cases were contacted for follow up, 1491 (66,2%) patients were interviewed by phone and 142 (6,3%) women returned the questionnaire. In 72,5% of the con-tacted cases follow-up data is available.
The mean age of all patients who do-nated their tumor specimen is 60,3 years. 78,9% of the tumors are ER-positive, 11,4% triple negative. The data includes 20 cases of recurrence and 61 cases of metastases. Conclusion: Within 16 months PATH contacted 40% of all patients included in the bio bank and gained follow up data. Thus PATH will provide a great variety and quantity of fresh frozen tissue and blood samples with excellent quality and a mean follow up of 5 years in less than 12 months.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-13-01.
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Affiliation(s)
- T Anzeneder
- Stiftung PATH-Patients’ Tumor Bank of Hope, Augsburg, Bavaria, Germany
| | - G Ailer
- Stiftung PATH-Patients’ Tumor Bank of Hope, Augsburg, Bavaria, Germany
| | - U Ohlms
- Stiftung PATH-Patients’ Tumor Bank of Hope, Augsburg, Bavaria, Germany
| | - DC Schmitt
- Stiftung PATH-Patients’ Tumor Bank of Hope, Augsburg, Bavaria, Germany
| | - C. Waldner
- Stiftung PATH-Patients’ Tumor Bank of Hope, Augsburg, Bavaria, Germany
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23
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Abstract
Organozinc, -magnesium, and -lithium nucleophiles initiate a Brook/Ireland-Claisen rearrangement sequence of allylic silyl glyoxylates resulting in the formation of gamma,delta-unsaturated alpha-silyloxy acids.
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Affiliation(s)
- Daniel C Schmitt
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
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24
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Nicewicz DA, Satterfield AD, Schmitt DC, Johnson JS. Self-consistent synthesis of the squalene synthase inhibitor zaragozic acid C via controlled oligomerization. J Am Chem Soc 2009; 130:17281-3. [PMID: 19053214 DOI: 10.1021/ja808347q] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite the prevalence of repeating subunits in chiral natural products, stereocontrolled oligomerization is a largely unexplored strategy for construction of carbon skeletal frameworks. This report describes the use of silyl glyoxylates as dipolar glycolic acid synthons in a controlled oligomerization reaction for the efficient construction of the squalene synthase inhibitor zaragozic acid C. This new methodology allows rapid, stereocontrolled formation of the carbon skeleton with a desirable protecting group scheme while minimizing functional group repair and oxidation state manipulations.
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Affiliation(s)
- David A Nicewicz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
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25
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Lux MP, Radosavac D, Tänzer TD, Kara H, Bani MR, Schrauder M, Schmitt DC, Haidinger R, Overbeck-Schulte B, Schulte H, Beckmann MW, Fasching PA. Einflussfaktoren von Patientinnen mit einem Mammakarzinom auf die Vorstellung über Therapieeffektivitäten und Akzeptanz von Therapieoptionen – Ergebnisse der Gut Informieren – Gemeinsam Entscheiden!-Studie. Geburtshilfe Frauenheilkd 2008. [DOI: 10.1055/s-2008-1079206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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26
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Lux MP, Radosavac D, Tänzer TD, Kara H, Bani MR, Schrauder M, Schmitt DC, Haidinger R, Overbeck-Schulte B, Schulte H, Beckmann MW, Fasching PA. Patientinnen mit einem Mammakarzinom und ihre Ärztinnen und Ärzte unterscheiden sich in der Beurteilung des notwendigen Benefits von Therapieoption – Ergebnisse der Gut Informieren – Gemeinsam Entscheiden!-Studie. Geburtshilfe Frauenheilkd 2008. [DOI: 10.1055/s-2008-1079205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Abstract
Synthesis of the spiroisoxazoline natural product (+)-calafianin is reported using asymmetric nucleophilic epoxidation and nitrile oxide cycloaddition as key steps. Synthesis and spectral analysis of all calafianin stereoisomers led to unambiguous assignment of relative and absolute stereochemistry.
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Affiliation(s)
- Sujata Bardhan
- Department of Chemistry and Center for Chemical Methodology and Library Development, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
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