1
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Ikeda R, Nishio T, Kanomata K, Akai S. Nucleophilic Deprotection of p-Methoxybenzyl Ethers Using Heterogeneous Oxovanadium Catalyst. Chem Pharm Bull (Tokyo) 2024; 72:213-219. [PMID: 38382974 DOI: 10.1248/cpb.c23-00897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Nucleophilic deprotection of p-methoxybenzyl (PMB) [p-methoxyphenylmethyl (MPM)] ethers was developed using a heterogeneous oxovanadium catalyst V-MPS4 and a thiol nucleophile. The deprotection method had a wide reaction scope, including PMB ethers of primary, secondary, and tertiary alcohols bearing various functional groups. In addition, the PMB ether of an oxidation-labile natural product was successfully removed by V-MPS4 catalysis, while a common oxidative method of PMB deprotection afforded a complex mixture. The V-MPS4 catalyst was reusable up to six times without a significant loss in the product yield. The advantages of using the heterogeneous catalyst were further demonstrated by conducting the deprotection reaction in a continuous flow process, which resulted in a 2.7-fold higher catalyst turnover number and 60-fold higher turnover frequency compared to those of the corresponding batch reaction.
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Affiliation(s)
- Rei Ikeda
- Graduate School of Pharmaceutical Sciences, Osaka University
| | - Tomoya Nishio
- Graduate School of Pharmaceutical Sciences, Osaka University
| | - Kyohei Kanomata
- Graduate School of Pharmaceutical Sciences, Osaka University
| | - Shuji Akai
- Graduate School of Pharmaceutical Sciences, Osaka University
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2
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Miyazaki M, Ura Y. Palladium/Iron-Catalyzed Wacker-Type Oxidation of Aliphatic Terminal and Internal Alkenes Using O 2. ACS OMEGA 2023; 8:41983-41990. [PMID: 37969998 PMCID: PMC10634151 DOI: 10.1021/acsomega.3c07577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 10/06/2023] [Indexed: 11/17/2023]
Abstract
The Wacker-type oxidation of aliphatic terminal alkenes proceeds using a Pd/Fe catalyst system under mild reaction conditions using 1 atm O2 without other additives. The use of 1,2-dimethoxyethane/H2O as a mixed solvent was effective. The slow addition of alkenes is also important for improving product yields. Fe(III) citrate was the most efficient cocatalyst among the iron complexes examined, whereas other complexes such as FeSO4, Fe2(SO4)3, Fe(NO3)3, and Fe2O3 were also operative. This method is also applicable to aliphatic internal alkenes, which are generally difficult to oxidize using conventional Pd/Cu catalyst systems. The gram-scale synthesis and reuse of the Pd catalysts were also demonstrated.
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Affiliation(s)
- Mayu Miyazaki
- Department of Chemistry,
Biology, and Environmental Science, Faculty of Science, Nara Women’s University, Kitauoyanishi-machi, Nara 630-8506, Japan
| | - Yasuyuki Ura
- Department of Chemistry,
Biology, and Environmental Science, Faculty of Science, Nara Women’s University, Kitauoyanishi-machi, Nara 630-8506, Japan
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3
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Greve RD, Jensen HH. Lewis Acid Promoted Deprotection of Benzylidene Acetals and p-Methoxybenzyl Ethers with Mercaptoacid Acid as Scavenger. Org Lett 2023; 25:3628-3632. [PMID: 37191475 DOI: 10.1021/acs.orglett.3c00958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We demonstrate a new and high-yielding method for removal of benzylidene acetals and para-methoxybenzyl ethers under catalytic conditions (BF3:OEt2 orFeCl3, 10 mol%) with mercaptoacetic acid as a scavenger. The reaction coproducts are converted to water-soluble molecules, which can be removed by aqueous extraction, thereby bypassing the need for chromatographic purification. The reaction was demonstrated on both multimilligram and multigram scale.
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Affiliation(s)
- Rasmus D Greve
- Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Henrik H Jensen
- Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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4
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Luo T, Xu TT, Guo YF, Dong H. SnCl 4 Promoted Efficient Cleavage of Acetal/Ketal Groups with the Assistance of Water in CH 2Cl 2. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238258. [PMID: 36500346 PMCID: PMC9736348 DOI: 10.3390/molecules27238258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022]
Abstract
Acetalization and deacetalation are a pair of routine manipulations to protect and deprotect the 4- and 6-hydroxyl groups of glycosides in the synthesis of glycosyl building blocks. In this study, we found that treatment of SnCl4 with various carbohydrates containing acetal/ketal groups with the assistance of water in CH2Cl2 led to deacetalization/deketalization products in almost quantitative yields. In addition, for substrates containing both acetal/ketal and p-methoxylbenzyl groups, we also found that the p-methoxylbenzyl group was selectively cleaved by the use of a catalytic amount of SnCl4, while the acetal/ketal groups remained. Furthermore, based on this, 4,6-benzylidene glycosides can be conveniently converted to 4,6-OAc or 4-OH, 6-OAc glycosides.
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5
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Monkcom EC, Negenman HA, Masferrer-Rius E, Lutz M, Ye S, Bill E, Klein Gebbink RJ. 2H1C Mimicry: Bioinspired Iron and Zinc Complexes Supported by N,N,O Phenolate Ligands. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202101046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Emily C. Monkcom
- Utrecht University: Universiteit Utrecht Organic Chemistry and Catalysis Universiteitsweg 99 3584CG Utrecht NETHERLANDS
| | - Hidde A. Negenman
- Utrecht University: Universiteit Utrecht Organic Chemistry and Catalysis Universiteitsweg 99 3584CG Utrecht NETHERLANDS
| | - Eduard Masferrer-Rius
- Utrecht University: Universiteit Utrecht Organic Chemistry and Catalysis Universiteitsweg 99 3584CG Utrecht NETHERLANDS
| | - Martin Lutz
- Utrecht University: Universiteit Utrecht Crystal and Structural Chemistry Universiteitsweg 99 3584CG Utrecht NETHERLANDS
| | - Shengfa Ye
- Chinese Academy of Sciences Institute of Chemistry 457 Zhongshan Road 116023 Dalian CHINA
| | - Eckhard Bill
- Max Planck Institute of Coal Research: Max-Planck-Institut fur Kohlenforschung Inorganic Spectroscopy Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr GERMANY
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6
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Zuleta EC, Bozell JJ. Alkylation of monomeric, dimeric, and polymeric lignin models through carbon-hydrogen activation using Ru-catalyzed Murai reaction. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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7
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Polemic against conclusions drawn in “Palladium/iodide catalyzed oxidative carbonylation of aniline to diphenylurea: Effect of ppm amounts of iron salts” (J. Catal. 369 (2019) 257–266). J Catal 2019. [DOI: 10.1016/j.jcat.2019.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Ikeuchi K, Murasawa K, Ohara K, Yamada H. p-Methylbenzyl Group: Oxidative Removal and Orthogonal Alcohol Deprotection. Org Lett 2019; 21:6638-6642. [PMID: 31437002 DOI: 10.1021/acs.orglett.9b02144] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We describe the practical removal of p-methylbenzyl (MBn) protections of alcohols by treatment with 2,3-dichloro-5,6-dicyano-p-benzoquinone. When a molecule bears benzyl and MBn groups, the oxidant selectively removes the latter groups. Further, the MBn groups tolerate ceric ammonium nitrate, resulting in chemoselective removal of the p-methoxybenzyl group in the presence of the MBn groups. These orthogonal alcohol deprotections would provide novel synthetic strategies of organic compounds.
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Affiliation(s)
- Kazutada Ikeuchi
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan.,Department of Chemistry, Faculty of Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo 060-0810, Japan
| | - Kentaro Murasawa
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
| | - Kenya Ohara
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
| | - Hidetoshi Yamada
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
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9
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Sajiki H, Sawama Y, Kawajiri T, Yamamoto Y, Shishido Y, Goto R. Acetal Elimination Reaction Accompanied with Regioselective Ring Opening of 1,4-Bisacetal-1,4-epoxy-1,4-dihydronaphthalenes. HETEROCYCLES 2019. [DOI: 10.3987/com-18-s(f)50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Miao M, Jin M, Xu H, Chen P, Zhang S, Ren H. Synthesis of 5H-Dibenzo[c,g]chromen-5-ones via FeCl3-Mediated Tandem C–O Bond Cleavage/6π Electrocyclization/Oxidative Aromatization. Org Lett 2018; 20:5718-5722. [DOI: 10.1021/acs.orglett.8b02434] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Maozhong Miao
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P. R. China
| | - Mengchao Jin
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P. R. China
| | - Huaping Xu
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P. R. China
| | - Panpan Chen
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P. R. China
| | - Shouzhi Zhang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P. R. China
| | - Hongjun Ren
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P. R. China
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11
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Mao Y, Liu Y, Hu Y, Wang L, Zhang S, Wang W. Pd-Catalyzed Debenzylation and Deallylation of Ethers and Esters with Sodium Hydride. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00185] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Yujian Mao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, 199 Ren’ai Road, Suzhou, Jiangsu 215123, China
| | - Ye Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, 199 Ren’ai Road, Suzhou, Jiangsu 215123, China
| | - Yanwei Hu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, 199 Ren’ai Road, Suzhou, Jiangsu 215123, China
| | - Liang Wang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Shilei Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, 199 Ren’ai Road, Suzhou, Jiangsu 215123, China
| | - Wei Wang
- State Key Laboratory of Bioengineering Reactor, and Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
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12
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Wu K, Xie ZP, Cui DM, Zhang C. Formal total synthesis of salvianolic acid N. Org Biomol Chem 2018; 16:832-837. [DOI: 10.1039/c7ob03025h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Salvianolic acid N was synthesized starting from 3,4-dimethoxybenzaldehyde in 11 steps and with an overall yield of 11%. The key reaction steps were the Wittig reaction for Z-stereoselectivity, the copper catalyzed intramolecular cyclization for seven membered ring skeleton, and the deprotected allylic group with Pd catalysis.
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Affiliation(s)
- Kong Wu
- College of Pharmaceutical Science
- Zhejiang University of Technology
- Hangzhou 310014
- China
| | - Zhong Pao Xie
- College of Pharmaceutical Science
- Zhejiang University of Technology
- Hangzhou 310014
- China
| | - Dong-Mei Cui
- College of Pharmaceutical Science
- Zhejiang University of Technology
- Hangzhou 310014
- China
| | - Chen Zhang
- School of Pharmaceutical Sciences
- Zhejiang University
- Hangzhou 310058
- China
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13
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Wu C, Ikejiri Y, Zeng X, Elsegood MRJ, Redshaw C, Yamato T. Synthesis of Mono-O-alkylated Homooxacalix[3]arene and a Protection-Deprotection Strategy for Homooxacalix[3]arene. Org Lett 2017; 19:66-69. [PMID: 27936785 DOI: 10.1021/acs.orglett.6b03338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The regioselective synthesis of mono-O-alkylated homooxacalix[3]arene is accomplished for the first time. The synthetic route relies on two key steps: (i) a facile protection of two OH groups at the lower rim of the homooxacalix[3]arene and (ii) the deprotection of 9-anthrylmethyl groups via the Pd/C-catalyzed hydrogenation under atmospheric hydrogen. An efficient protection-deprotection strategy for the functionalization of homooxacalix[3]arene is presented.
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Affiliation(s)
- Chong Wu
- Department of Applied Chemistry, Faculty of Science and Engineering, Saga University , Honjo-machi 1, Saga 840-8502, Japan
| | - Yusuke Ikejiri
- Department of Applied Chemistry, Faculty of Science and Engineering, Saga University , Honjo-machi 1, Saga 840-8502, Japan
| | - Xi Zeng
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University , Guiyang, Guizhou 550025, China
| | - Mark R J Elsegood
- Chemistry Department, Loughborough University , Loughborough, Leicestershire LE11 3TU, U.K
| | - Carl Redshaw
- School of Mathematics and Physical Sciences, The University of Hull , Cottingham Road, Hull, Yorkshire HU6 7RX, U.K
| | - Takehiko Yamato
- Department of Applied Chemistry, Faculty of Science and Engineering, Saga University , Honjo-machi 1, Saga 840-8502, Japan
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14
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Schiavo L, Jeanmart L, Lanners S, Choppin S, Hanquet G. FeCl3·6H2O/acetaldehyde, a versatile system for the deprotection of ketals and acetals via a transacetalization process. NEW J CHEM 2017. [DOI: 10.1039/c6nj03439j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mild and efficient catalytic deprotection of ketals/acetals mediated by FeCl3·6H2O/acetaldehyde has been described in this paper.
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Affiliation(s)
- Lucie Schiavo
- Laboratoire de Chimie Moléculaire (UMR CNRS 7509)
- University of Strasbourg
- ECPM
- 67087 Strasbourg
- France
| | - Loïc Jeanmart
- Unité de Chimie Organique et Bioorganique Supramoléculaire
- University of Namur
- 5000 Namur
- Belgium
| | - Steve Lanners
- Unité de Chimie Organique et Bioorganique Supramoléculaire
- University of Namur
- 5000 Namur
- Belgium
| | - Sabine Choppin
- Laboratoire de Chimie Moléculaire (UMR CNRS 7509)
- University of Strasbourg
- ECPM
- 67087 Strasbourg
- France
| | - Gilles Hanquet
- Laboratoire de Chimie Moléculaire (UMR CNRS 7509)
- University of Strasbourg
- ECPM
- 67087 Strasbourg
- France
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15
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Sawama Y, Masuda M, Nakatani R, Yokoyama H, Monguchi Y, Dohi T, Kita Y, Sajiki H. Site-Selective Iron(III) Chloride-Catalyzed Arylation of 4-Aryl-4-methoxy-2,5-cyclohexadienones for the Synthesis of Polyarylated Phenols. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600577] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Yoshinari Sawama
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Masahiro Masuda
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Ryosuke Nakatani
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Hiroki Yokoyama
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Yasunari Monguchi
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Toshifumi Dohi
- College of Pharmaceutical Sciences; Ritsumeikan University; 1-1-1 Nojihigashi Kusatsu Shiga 525-8577 Japan
| | - Yasuyuki Kita
- College of Pharmaceutical Sciences; Ritsumeikan University; 1-1-1 Nojihigashi Kusatsu Shiga 525-8577 Japan
| | - Hironao Sajiki
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
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16
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Mishiro K, Hu F, Paley DW, Min W, Lambert TH. Macrosteres: The Deltic Guanidinium Ion. European J Org Chem 2016; 2016:1655-1659. [PMID: 27790071 PMCID: PMC5079176 DOI: 10.1002/ejoc.201600137] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Indexed: 11/12/2022]
Abstract
The "deltic guanidinium" ion is described here as a "macrostere" of the guanidinium ion. The use of the 2,4-dimethoxybenzyl protecting group allows for the synthesis of the fully unsubstituted parent compound and a variety of derivatives bearing multiple N-H functions for the first time. Deltic urea, deltic thiourea, and deltic benzamidine are also synthesized. A comparison of the physical properties of guanidinium and deltic guanidinium ions is provided. The use of a deltic guanidinium dendrimer for cell transport is demonstrated.
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Affiliation(s)
- Kenji Mishiro
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027 USA, Fax: (+) 212-932-1289, http://www.columbia.edu/cu/chemistry/groups/lambert/
| | - Fanghao Hu
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027 USA, Fax: (+) 212-932-1289, http://www.columbia.edu/cu/chemistry/groups/lambert/
| | - Daniel W. Paley
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027 USA, Fax: (+) 212-932-1289, http://www.columbia.edu/cu/chemistry/groups/lambert/
| | - Wei Min
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027 USA, Fax: (+) 212-932-1289, http://www.columbia.edu/cu/chemistry/groups/lambert/
| | - Tristan H. Lambert
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027 USA, Fax: (+) 212-932-1289, http://www.columbia.edu/cu/chemistry/groups/lambert/
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17
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Zhang JZ, Tang Y. Iron-Catalyzed Regioselective Oxo- and Hydroxy-Phthalimidation of Styrenes: Access to α-Hydroxyphthalimide Ketones. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201500732] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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18
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Sawama Y, Masuda M, Honda A, Yokoyama H, Park K, Yasukawa N, Monguchi Y, Sajiki H. Additional Nucleophile-Free FeCl 3-Catalyzed Green Deprotection of 2,4-Dimethoxyphenylmethyl-Protected Alcohols and Carboxylic Acids. Chem Pharm Bull (Tokyo) 2016; 64:778-84. [DOI: 10.1248/cpb.c16-00161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Rival N, Albornoz Grados A, Schiavo L, Colobert F, Hanquet G. Mild deprotection of PMB ethers using tert-butyl bromide. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.10.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Asai S, Yabe Y, Goto R, Nagata S, Monguchi Y, Kita Y, Sajiki H, Sawama Y. Gold-Catalyzed Benzylic Azidation of Phthalans and Isochromans and Subsequent FeCl3-Catalyzed Nucleophilic Substitutions. Chem Pharm Bull (Tokyo) 2015; 63:757-61. [PMID: 26423031 DOI: 10.1248/cpb.c15-00347] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The benzylic positions of the phthalan and isochroman derivatives (1) as benzene-fused cyclic ethers effectively underwent gold-catalyzed direct azidation using trimethylsilylazide (TMSN3) to give the corresponding 1-azidated products (2) possessing the N,O-acetal partial structure. The azido group of the N,O-acetal behaved as a leaving group in the presence of catalytic iron(III) chloride, and 1-aryl or allyl phthalan and isochroman derivatives were obtained by nucleophilic arylation or allylation, respectively. Meanwhile, a double nucleophilic substitution toward the 1-azidated products (2) occurred at the 1-position using indole derivatives as a nucleophile accompanied by elimination of the azido group and subsequent ring opening of the cyclic ether nucleus produced the bisindolylarylmethane derivatives.
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21
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Okada Y, Wakamatsu H, Sugai M, Kauppinen EI, Chiba K. Acid-Triggered Colorimetric Hydrophobic Benzyl Alcohols for Soluble Tag-Assisted Liquid-Phase Synthesis. Org Lett 2015; 17:4264-7. [PMID: 26274781 DOI: 10.1021/acs.orglett.5b02057] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Simple screening of acid-triggered reactions of methoxybenzyl alcohols led to the development of a novel colorimetric hydrophobic benzyl alcohol (HBA) tag. HBA tag-3 (14) retained high solubility in less polar solvents and excellent precipitation properties in polar solvents. Our routine procedure for tag-assisted liquid phase peptide synthesis was applied using HBA tag-3 (14), and an effective synthesis of β-sheet breaker peptide iAβ5 (4) was achieved. The tagged peptides showed a vivid blue color under acidic conditions both on TLC plates and in solution, enabling quantitative assay.
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Affiliation(s)
- Yohei Okada
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology , 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Hiroki Wakamatsu
- Department of Applied Biological Chemistry, Tokyo University of Agriculture and Technology , 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Masae Sugai
- Department of Applied Biological Chemistry, Tokyo University of Agriculture and Technology , 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Esko I Kauppinen
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology , 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.,Department of Applied Physics, Aalto University School of Science , Puumiehenkuja 2, 00076 Aalto, Finland
| | - Kazuhiro Chiba
- Department of Applied Biological Chemistry, Tokyo University of Agriculture and Technology , 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
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22
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Volbeda AG, Kistemaker HAV, Overkleeft HS, van der Marel GA, Filippov DV, Codée JDC. Chemoselective Cleavage of p-Methoxybenzyl and 2-Naphthylmethyl Ethers Using a Catalytic Amount of HCl in Hexafluoro-2-propanol. J Org Chem 2015; 80:8796-806. [PMID: 26230920 DOI: 10.1021/acs.joc.5b01030] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new, fast, mild and chemoselective deprotection method to cleave p-methoxybenzyl and 2-naphthylmethyl ethers using catalytic amounts of hydrochloric acid in a 1:1 mixture of hexafluoro-2-propanol (HFIP) and methylene chloride (DCM) is described. The scope of the methodology becomes apparent from 14 examples of orthogonally protected monosaccharides that are subjected to HCl/HFIP treatment. The applicability of the HCl/HFIP method is illustrated by the synthesis of a sulfated β-mannuronic acid disaccharide.
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Affiliation(s)
- Anne Geert Volbeda
- Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Hans A V Kistemaker
- Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Herman S Overkleeft
- Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Gijsbert A van der Marel
- Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Dmitri V Filippov
- Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands
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23
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Sawama Y, Kawajiri T, Asai S, Yasukawa N, Shishido Y, Monguchi Y, Sajiki H. Biarylmethane and Fused Heterocyclic Arene Synthesis via in Situ Generated o- and/or p-Naphthoquinone Methides. J Org Chem 2015; 80:5556-65. [PMID: 25938963 DOI: 10.1021/acs.joc.5b00434] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
o- and/or p-naphthoquinone methides (NQMs) can be selectively prepared by the ring opening of 1-(siloxymethyl)-1,4-epoxy-1,4-dihydronaphthalene derivatives based on a substituent effect at the 4 position of the substrates. The 4-alkyl- or silyl-substituted 1-(siloxymethyl)-1,4-epoxy-1,4-dihydronaphthalene was transformed to o-NQM (1-naphthoquinone-2-methide), which underwent Friedel-Crafts 1,4-addition of the α,β-unsaturated carbonyl moiety to provide the 2-benzyl-1-naphthol as the biarylmethane and [4 + 2]-cycloaddition with a dienophile to give the fused heterocyclic arene. Meanwhile, the 4-unsubstituted 1-(siloxymethyl)-1,4-epoxy-1,4-dihydronaphthalene could be converted to the corresponding 4-benzyl-1-naphthol by the Friedel-Crafts 1,6-addition of p-NQM (1-naphthoquinone-4-methide) generated by the site-selective ring opening of the 1,4-epoxy moiety. Furthermore, the 4-(siloxymethyl)-(1,4-bis(siloxymethyl))-1,4-epoxy-1,4-dihydronaphthalene was transformed into a 2,4-bisbenzyl-1-naphthol or pentacyclic derivative via both the o- and p-NQM intermediates.
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Affiliation(s)
- Yoshinari Sawama
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Takahiro Kawajiri
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Shota Asai
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Naoki Yasukawa
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Yuko Shishido
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Yasunari Monguchi
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Hironao Sajiki
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
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