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Dou X, Patel BA, D'Amico T, Subramanian C, Cousineau E, Yi Y, Cohen M, Blagg BSJ. Synthesis and Evaluation of Simplified Cruentaren A Analogues. J Org Chem 2022; 87:9940-9956. [PMID: 35894845 DOI: 10.1021/acs.joc.2c00948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The 90 kDa heat shock protein (Hsp90) belongs to a group of molecular chaperones that regulate homeostasis via the folding of nascent polypeptides into their biologically active proteins, many of which are involved in cancer development and progression. As a result, inhibition of Hsp90 is an exciting area of research for the treatment of cancer. However, most of the 18 Hsp90 N-terminal inhibitors evaluated in clinical trials exhibited deleterious side effects and toxicities. Cruentaren A is a natural product that manifests potent anticancer activity against various human cancer cell lines via disruption of interactions between Hsp90α and F1FO ATP synthase, which does not induce the pro-survival, heat shock response, a major limitation associated with current Hsp90 inhibitors. However, the development of cruentaren A as a new anticancer agent has been hindered by its complex structure. Herein, we systematically removed the functionalities present in fragment 2 of cruentaren A and incorporated some key structural modifications from previous work, which produced 12 simplified analogues. Our studies determined that all functional groups present in fragment 2 are essential for cruentaren A's anticancer activity.
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Affiliation(s)
- Xiaozheng Dou
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Bhargav A Patel
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Terin D'Amico
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Chitra Subramanian
- General Surgery Clinic, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Eric Cousineau
- General Surgery Clinic, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yi Yi
- Global Blood Therapeutics, San Francisco, California 94080, United States
| | - Mark Cohen
- General Surgery Clinic, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brian S J Blagg
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, Indiana 46556, United States
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2
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Joshi BD, Chisholm JD. Formation of Pyrroloindolines via the Alkylation of Tryptamines with Trichloroacetimidates. Tetrahedron Lett 2021; 77:153256. [PMID: 34334833 PMCID: PMC8321311 DOI: 10.1016/j.tetlet.2021.153256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Pyrroloindolines and related systems are present in a large number of complex natural products. These core structures have generated considerable synthetic interest, as many of the compounds possess challenging, elaborate structures and interesting biological properties. Recently we have focused on using trichloroacetimidates for the synthesis of these fascinating molecules. Trichloroacetimidates can be used as an electrophilic source of an alkyl group to form the pyrroloindoline directly from tryptamine derivatives. In this manner trichloroacetimidates provide a flexible solution to forming highly functionalized pyrroloindoline core structures, needing only a catalytic amount of a Lewis acid to effect the requisite transformations.
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Affiliation(s)
- Bhaskar D Joshi
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, NY 13244
| | - John D Chisholm
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, NY 13244
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3
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Esterifications with 2-(Trimethylsilyl)ethyl 2,2,2-Trichloroacetimidate. ORGANICS 2021. [DOI: 10.3390/org2010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
2-(Trimethylsilyl)ethyl 2,2,2-trichloroacetimidate is readily synthesized from 2-trimethylsilylethanol in high yield. This imidate is an effective reagent for the formation of 2-trimethylsilylethyl esters without the need for an exogenous promoter or catalyst, as the carboxylic acid substrate is acidic enough to promote ester formation without an additive. A deuterium labeling study indicated that a β-silyl carbocation intermediate is involved in the transformation.
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4
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Suzuki T, Mate NA, Adhikari AA, Chisholm JD. Dialkylation of Indoles with Trichloroacetimidates to Access 3,3-Disubstituted Indolenines. Molecules 2019; 24:molecules24224143. [PMID: 31731742 PMCID: PMC6891773 DOI: 10.3390/molecules24224143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 12/02/2022] Open
Abstract
2-Substituted indoles may be directly transformed to 3,3-dialkyl indolenines with trichloroacetimidate electrophiles and the Lewis acid TMSOTf. These reactions provide rapid access to complex indolenines which are present in a variety of complex natural products and medicinally relevant small molecule structures. This method provides an alternative to the use of transition metal catalysis. The indolenines are readily transformed into spiroindoline systems which are privileged scaffolds in medicinal chemistry.
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Mahajani NS, Meador RIL, Smith TJ, Canarelli SE, Adhikari AA, Shah JP, Russo CM, Wallach DR, Howard KT, Millimaci AM, Chisholm JD. Ester Formation via Symbiotic Activation Utilizing Trichloroacetimidate Electrophiles. J Org Chem 2019; 84:7871-7882. [PMID: 31117564 DOI: 10.1021/acs.joc.9b00745] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Trichloroacetimidates are useful reagents for the synthesis of esters under mild conditions that do not require an exogenous promoter. These conditions avoid the undesired decomposition of substrates with sensitive functional groups that are often observed with the use of strong Lewis or Brønsted acids. With heating, these reactions have been extended to benzyl esters without electron-donating groups. These inexpensive and convenient methods should find application in the formation of esters in complex substrates.
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Affiliation(s)
- Nivedita S Mahajani
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Rowan I L Meador
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Tomas J Smith
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Sarah E Canarelli
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Arijit A Adhikari
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Jigisha P Shah
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Christopher M Russo
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Daniel R Wallach
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Kyle T Howard
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - Alexandra M Millimaci
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
| | - John D Chisholm
- Department of Chemistry , Syracuse University , 1-014 Center for Science and Technology , Syracuse , New York 13244 , United States
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6
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Abstract
Substituted indole scaffolds are often utilized in medicinal chemistry as they regularly possess significant pharmacological activity. Therefore the development of simple, inexpensive and efficient methods for alkylating the indole heterocycle continues to be an active research area. Reported are reactions of trichloroacetimidate electrophiles and indoles to address the challenges of accessing alkyl decorated indole structures. These alkylations perform best when either the indole or the imidate is functionalized with electron withdrawing groups to avoid polyalkylation.
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Affiliation(s)
- Tamie Suzuki
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, NY 13244
| | - John D Chisholm
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, NY 13244
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Mahajani NS, Chisholm JD. Promoter free allylation of trichloroacetimidates with allyltributylstannanes under thermal conditions to access the common 1,1'-diarylbutyl pharmacophore. Org Biomol Chem 2018; 16:4008-4012. [PMID: 29766199 DOI: 10.1039/c8ob00687c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
1,1'-Diarylbutyl groups are a common pharmacophore found in many biologically active small molecules. To access these systems under mild conditions, the reaction of diarylmethyl trichloroacetimidates with allyltributylstannanes was explored. Simply heating allyltributylstannane with the trichloroacetimidate resulted in substitution of the imidate with an allyl group. Unlike other methods used to access these systems, no strong base, transition metal catalyst, Brønsted acid or Lewis acid promoter was required to affect the transformation. Conversions are best with electron rich benzylic trichloroacetimidate systems, where excellent yields are achieved just by refluxing the reactants together in nitromethane.
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Affiliation(s)
- Nivedita S Mahajani
- Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244, USA.
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8
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Mahajani NS, Chisholm JD. Synthesis of 1,1'-Diarylethanes and Related Systems by Displacement of Trichloroacetimidates with Trimethylaluminum. J Org Chem 2018; 83:4131-4139. [PMID: 29478311 PMCID: PMC5889320 DOI: 10.1021/acs.joc.8b00027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Benzylic trichloroacetimidates are readily displaced by trimethylaluminum under Lewis acid promoted conditions to provide the corresponding methyl substitution product. This method is a convenient way to access 1,1'-diarylethanes and related systems, which play a significant role in medicinal chemistry, with a number of systems owing their biological activity to this functionality. Most benzylic substrates undergo ready displacement, with electron deficient systems being the exception. The use of an enantiopure imidate showed significant racemization, implicating the formation of a cationic intermediate.
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Affiliation(s)
- Nivedita S. Mahajani
- Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244
| | - John D. Chisholm
- Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244
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9
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Engl OD, Saadi J, Cosimi E, Wennemers H. Synthesis of Monothiomalonates - Versatile Thioester Enolate Equivalents for C-C Bond Formations. Helv Chim Acta 2017. [DOI: 10.1002/hlca.201700196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Oliver D. Engl
- Laboratorium für Organische Chemie; D-CHAB; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Jakub Saadi
- Laboratorium für Organische Chemie; D-CHAB; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Elena Cosimi
- Laboratorium für Organische Chemie; D-CHAB; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Helma Wennemers
- Laboratorium für Organische Chemie; D-CHAB; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
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10
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McGregor LM, Jenkins ML, Kerwin C, Burke JE, Shokat KM. Expanding the Scope of Electrophiles Capable of Targeting K-Ras Oncogenes. Biochemistry 2017. [PMID: 28621541 DOI: 10.1021/acs.biochem.7b00271] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is growing interest in reversible and irreversible covalent inhibitors that target noncatalytic amino acids in target proteins. With a goal of targeting oncogenic K-Ras variants (e.g., G12D) by expanding the types of amino acids that can be targeted by covalent inhibitors, we survey a set of electrophiles for their ability to label carboxylates. We functionalized an optimized ligand for the K-Ras switch II pocket with a set of electrophiles previously reported to react with carboxylates and characterized the ability of these compounds to react with model nucleophiles and oncogenic K-Ras proteins. Here, we report that aziridines and stabilized diazo groups preferentially react with free carboxylates over thiols. Although we did not identify a warhead that potently labels K-Ras G12D, we were able to study the interactions of many electrophiles with K-Ras, as most of the electrophiles rapidly label K-Ras G12C. We characterized the resulting complexes by crystallography, hydrogen/deuterium exchange, and differential scanning fluorimetry. Our results both demonstrate the ability of a noncatalytic cysteine to react with a diverse set of electrophiles and emphasize the importance of proper spatial arrangements between a covalent inhibitor and its intended nucleophile. We hope that these results can expand the range of electrophiles and nucleophiles of use in covalent protein modulation.
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Affiliation(s)
- Lynn M McGregor
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco , San Francisco, California 94158, United States
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria , Victoria, BC V8W 2Y2, Canada
| | - Caitlin Kerwin
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco , San Francisco, California 94158, United States
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria , Victoria, BC V8W 2Y2, Canada
| | - Kevan M Shokat
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco , San Francisco, California 94158, United States
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11
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Adhikari AA, Suzuki T, Gilbert RT, Linaburg MR, Chisholm JD. Rearrangement of Benzylic Trichloroacetimidates to Benzylic Trichloroacetamides. J Org Chem 2017; 82:3982-3989. [PMID: 28323428 DOI: 10.1021/acs.joc.7b00245] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The rearrangement of allylic trichloroacetimidates is a well-known transformation, but the corresponding rearrangement of benzylic trichloroacetimidates has not been explored as a method for the synthesis of benzylic amines. Conditions that provide the trichloroacetamide product from a benzylic trichloroacetimidate in high yield have been developed. Methods were also investigated to transform the trichloroacetamide product directly into the corresponding amine, carbamate, and urea. A cationic mechanism for the rearrangement is implicated by the available data.
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Affiliation(s)
- Arijit A Adhikari
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University , Syracuse, New York 13244, United States
| | - Tamie Suzuki
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University , Syracuse, New York 13244, United States
| | - Reesheda T Gilbert
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University , Syracuse, New York 13244, United States
| | - Matthew R Linaburg
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University , Syracuse, New York 13244, United States
| | - John D Chisholm
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University , Syracuse, New York 13244, United States
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12
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Wallach DR, Chisholm JD. Alkylation of Sulfonamides with Trichloroacetimidates under Thermal Conditions. J Org Chem 2016; 81:8035-42. [PMID: 27487402 PMCID: PMC5010445 DOI: 10.1021/acs.joc.6b01421] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An intermolecular alkylation of sulfonamides with trichloroacetimidates is reported. This transformation does not require an exogenous acid, base, or transition metal catalyst; instead the addition occurs in refluxing toluene without additives. The sulfonamide alkylation partner appears to be only limited by sterics, with unsubstituted sulfonamides providing better yields than more encumbered N-alkyl sulfonamides. The trichloroacetimidate alkylating agent must be a stable cation precursor for the substitution reaction to proceed under these conditions.
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Affiliation(s)
- Daniel R. Wallach
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, NY 13244
| | - John D. Chisholm
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, NY 13244
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13
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Adhikari AA, Chisholm JD. Lewis Acid Catalyzed Displacement of Trichloroacetimidates in the Synthesis of Functionalized Pyrroloindolines. Org Lett 2016; 18:4100-3. [PMID: 27486831 DOI: 10.1021/acs.orglett.6b02024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The pyrroloindoline core is found in many natural products. These structures often differ at the C3a position, which may be substituted with an oxygen, nitrogen, or sp(3)- or sp(2)-hybridized carbon. Utilizing a trichloroacetimidate leaving group, a diversity-oriented approach to these structures has been developed. The trichloroacetimidate intermediate allows for the rapid incorporation of anilines, alcohols, thiols, and carbon nucleophiles. This method was applied in the synthesis of arundinine and a formal synthesis of psychotriasine.
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Affiliation(s)
- Arijit A Adhikari
- Department of Chemistry, Syracuse University , 1-014 Center for Science and Technology, Syracuse, New York 13244, United States
| | - John D Chisholm
- Department of Chemistry, Syracuse University , 1-014 Center for Science and Technology, Syracuse, New York 13244, United States
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Howard KT, Duffy BC, Linaburg MR, Chisholm JD. Formation of DPM ethers using O-diphenylmethyl trichloroacetimidate under thermal conditions. Org Biomol Chem 2016; 14:1623-8. [PMID: 26691695 PMCID: PMC4986612 DOI: 10.1039/c5ob02455b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alcohols are effectively converted to their corresponding diphenylmethyl (DPM) ethers by reaction with O-diphenylmethyl trichloroacetimidate in refluxing toluene without the requirement of a catalyst or other additives. A number of acid and base sensitive substrates were protected in excellent yield using this new method without disturbing the pre-existing functionality present in these molecules. This reaction is the first example of the formation of an ether from stoichiometric amounts of a trichloroacetimidate and an alcohol without the addition of a Brønsted or Lewis acid catalyst.
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Affiliation(s)
- Kyle T Howard
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, USA.
| | - Brian C Duffy
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, USA.
| | - Matthew R Linaburg
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, USA.
| | - John D Chisholm
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, USA.
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Howard KT, Chisholm JD. Preparation and Applications of 4-Methoxybenzyl Esters in Organic Synthesis. ORG PREP PROCED INT 2016; 48:1-36. [PMID: 27546912 DOI: 10.1080/00304948.2016.1127096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Kyle T Howard
- Department of Chemistry, 1-014 Center for Science & Technology, Syracuse University, Syracuse, NY 13244, USA
| | - John D Chisholm
- Department of Chemistry, 1-014 Center for Science & Technology, Syracuse University, Syracuse, NY 13244, USA
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16
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17
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Wallach DR, Stege PC, Shah JP, Chisholm JD. Brønsted Acid Catalyzed Monoalkylation of Anilines with Trichloroacetimidates. J Org Chem 2015; 80:1993-2000. [DOI: 10.1021/jo5027222] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Daniel R. Wallach
- Department of Chemistry,
1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, United States
| | - Patrick C. Stege
- Department of Chemistry,
1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, United States
| | - Jigisha P. Shah
- Department of Chemistry,
1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, United States
| | - John D. Chisholm
- Department of Chemistry,
1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244, United States
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