1
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Ghosh AK, Yadav M. Synthesis of optically active SARS-CoV-2 Mpro inhibitor drug nirmatrelvir (Paxlovid): an approved treatment of COVID-19. Org Biomol Chem 2023; 21:5768-5774. [PMID: 37293830 PMCID: PMC10526638 DOI: 10.1039/d3ob00653k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nirmatrelvir (Paxlovid) is an FDA approved drug that targets SARS-COV-2 3CLprotease. We report an optically active synthesis of nirmatrelvir that avoids a critical epimerization step. Our initial coupling of gem-dimethyl bicyclo[3.1.0]proline methyl ester with tert-leucine-trifluoroacetamide using standard coupling reagents, EDC and HOBt, provided the corresponding dipeptide derivative in excellent yield, however, a significant epimerization was observed at the tert-leucine bearing chiral center. To circumvent this epimerization problem, we developed a ZnCl2-mediated direct N-trifluroacetylation of Boc-derivatives for the synthesis of nirmatrelvir. This protocol has been utilized for N-acyl bond formation with other anhydrides without epimerization. The present synthetic route can be useful for the synthesis of structural variants of nirmatrelvir without significant epimerization.
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Affiliation(s)
- Arun K Ghosh
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
| | - Monika Yadav
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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2
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Zhou C, Zheng H, Chen Y, Mao G, Deng GJ. Modular Synthesis of Tetrasubstituted Pyrroles through a Four-Component Cyclization Strategy Using Ammonium Salt as the Nitrogen Source. J Org Chem 2023; 88:1533-1544. [PMID: 36655334 DOI: 10.1021/acs.joc.2c02556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A four-component synthesis of tetrasubstituted pyrroles was developed under metal-free conditions. The pyrrole ring was formed in one pot through [2 + 1 + 1 + 1] condensation using ammonium salt as the nitrogen source. In this strategy, 1,4-naphthoquinones and maleimides were used as the versatile C2 fragments to provide substituted benzo[f]isoindole-4,9-diones and pyrrolo[3,4-c]pyrrole-1,3-diones, respectively. This work is highlighted by using ammonium salt as the nitrogen source, readily available starting materials and multibond formation (two C-C and two C-N bonds) in a single operation.
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Affiliation(s)
- Chunlan Zhou
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Haolin Zheng
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Ya Chen
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Guojiang Mao
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, PR China
| | - Guo-Jun Deng
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
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3
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Hashimoto M, Wang Z, Ishikawa S, Ohashi F, Sagisaka R, Murai Y, Puteri Tachrim Z, Suzuki T. Novel Synthesis and Properties of Optically Pure N-Trifluoroacetylphenylglycine Hydroxysuccinimide Ester. HETEROCYCLES 2022. [DOI: 10.3987/com-22-s(r)11] [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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4
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Lin ZQ, Li CD, Su JY, Niu WJ, Gao JR, Li YJ. Sequential Cu(II)-promoted oxidation/[3 + 2] cycloaddition/aromatization tandem reaction for the synthesis of 2-substituted benzo[f]isoindole-4,9-dione. CAN J CHEM 2020. [DOI: 10.1139/cjc-2019-0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An efficient method for the synthesis of 2-substituted benzo[f]isoindole-4,9-dione derivatives from N-substituted iminodiacetates and quinones via a Cu(II)-promoted oxidation/[3 + 2] cycloaddition/aromatization tandem reaction was reported. This tandem reaction uses a wide range of N-substituted iminodiacetate derivatives that contain the chain-alkyl, cycloalkyl, and aryl group on the N-atom. Based on optimized reaction conditions, the desired product of 2-substituted benzo[f]isoindole-4,9-diones was obtained in moderate to excellent yields. Taken together, the promising results of this research would provide an especially efficient strategy to synthesize polysubstituted pyrroles from easy available starting materials and promoted by cheaper Cu(OAc)2.
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Affiliation(s)
- Zhang-qi Lin
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Chao-dong Li
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jun-yi Su
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Wen-jie Niu
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jian-rong Gao
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yu-jin Li
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
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5
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Fang B, Meng JP, Luo Y. Crystal structure of methyl 2-(6,11-dioxo-2,3,6,11-tetrahydro-1 H-benzo[ f]pyrrolo[2,1- a]isoindole-5-carbonyl)benzoate, C 24H 17NO 5. Z KRIST-NEW CRYST ST 2020. [DOI: 10.1515/ncrs-2020-0278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
C24H17NO5, triclinic, P1̄ (no. 2), a = 8.5858(2) Å, b = 9.2397(4) Å, c = 13.7831(8) Å, α = 97.11(3)°, β = 103.23(3)°, γ = 113.33(3)°, V = 948.8(2) Å3, Z = 2, R
gt(F) = 0.0545, wR
ref(F
2) = 0.1669, T = 296(2) K.
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Affiliation(s)
- Bo Fang
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences , Chongqing 402160, P.R. China
| | - Jiang Ping Meng
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences , Chongqing 402160, P.R. China
| | - Yan Luo
- College of Pharmacy, Chongqing University of Arts and Sciences , Chongqing 402160, P.R. China
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6
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Walunj RM, Natu AD, Chikate RC, Paradkar MV, Narwade SC, Kathwate GH, Deobagkar DD. A non-lithiation route towards facile synthesis of bioactive 4, 9-dimethoxynaphthalide. SYNTHETIC COMMUN 2020. [DOI: 10.1080/00397911.2020.1794656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Raju M. Walunj
- Department of Chemistry, Post-Graduate and Research Centre, MES Abasaheb Garware College, Pune, India
| | - Arun D. Natu
- Department of Chemistry, Post-Graduate and Research Centre, MES Abasaheb Garware College, Pune, India
| | - Rajeev C. Chikate
- Department of Chemistry, Post-Graduate and Research Centre, MES Abasaheb Garware College, Pune, India
| | - Madhusudan V. Paradkar
- Department of Chemistry, Post-Graduate and Research Centre, MES Abasaheb Garware College, Pune, India
| | - Santosh C. Narwade
- Department of Zoology, Molecular Biology Research Laboratory, Centre for Advance Studies, Savitribai Phule Pune University, Pune, India
| | | | - Deepti D. Deobagkar
- Department of Zoology, Molecular Biology Research Laboratory, Centre for Advance Studies, Savitribai Phule Pune University, Pune, India
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7
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Lin ZQ, Li CD, Li YJ, Zhang YJ, Zhou ZC, Ye Q, Gao JR. Acid-induced intermolecular [3+2] cycloaddition/oxidation to synthesize polysubstituted benzo[ f]isoindole-4,9-diones. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.1177/1747519819867235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A novel one-pot 1,3-dipolar cycloaddition/oxidation reaction of 1,4-quinones, aromatic aldehydes, and N-substituted amino esters to construct polysubstituted benzo[ f]isoindole-4,9-diones induced by benzoic acid is reported. Based on optimized reaction conditions, various polysubstituted benzo[ f]isoindole-4,9-diones derivatives are obtained in moderate yields. This straightforward methodology employs mild reaction conditions, a green oxidant, and readily available starting materials. Notably, a wide range of substrates is tolerated.
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Affiliation(s)
- Zhang-qi Lin
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
| | - Chao-dong Li
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
| | - Yu-jin Li
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
| | - Yong-jian Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
| | - Zi-chun Zhou
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
| | - Qing Ye
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
| | - Jian-rong Gao
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, P.R. China
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8
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Tachrim ZP, Oida K, Ikemoto H, Ohashi F, Kurokawa N, Hayashi K, Shikanai M, Sakihama Y, Hashidoko Y, Hashimoto M. Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel-Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester. Molecules 2017; 22:molecules22101748. [PMID: 29039791 PMCID: PMC6151496 DOI: 10.3390/molecules22101748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/11/2017] [Accepted: 10/13/2017] [Indexed: 11/24/2022] Open
Abstract
Chiral N-protected α-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel–Crafts acylation of N-protected α-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxysuccinimide ester (OSu), which has high storage stability, can react rapidly with amino components and produces fewer side reactions, including racemization. This study reports the first synthesis and utilization of N-trifluoroacetyl (TFA)-protected α-amino acid-OSu as a potential acyl donor for Friedel–Crafts acylation into various arenes. The TFA-protected isoleucine derivative and its diastereomer TFA-protected allo-isoleucine derivative were investigated to check the retention of α-proton chirality in the Friedel–Crafts reaction. Further utilization of OSu in other branched-chain and unbranched-chain amino acids results in an adequate yield of TFA-protected α-amino aryl-ketone without loss of optical purity.
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Affiliation(s)
- Zetryana Puteri Tachrim
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Kazuhiro Oida
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Haruka Ikemoto
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Fumina Ohashi
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Natsumi Kurokawa
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Kento Hayashi
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Mami Shikanai
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Yasuko Sakihama
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Yasuyuki Hashidoko
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Makoto Hashimoto
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
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9
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Chen G, Liu H, Li S, Tang Y, Lu P, Xu K, Zhang Y. A Novel PPh 3 Mediated One-Pot Method for Synthesis of 3-Aryl or Alkyl 1,2-Benzisoxazoles. Org Lett 2017; 19:1792-1795. [PMID: 28357871 DOI: 10.1021/acs.orglett.7b00563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel, efficient, and facile protocol has been developed for transforming 2-hydroxybenzonitriles and bromides into a range of 3-aryl or alkyl substituted 1,2-benzisoxazoles in good to excellent yields mediated by PPh3. The electronic and steric effects of bromides on the reaction are discussed. This is the first example to construct a C-C bond and heterocycle in a Barbier-Grignard-type reaction featuring easier recovery of PPh3 than a metallic catalyst in one step.
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Affiliation(s)
- GuiFang Chen
- Department of Chemistry, College of Chemistry and Materials, Jinan University , Guangzhou 510632, China
| | - Hong Liu
- Department of Chemistry, College of Chemistry and Materials, Jinan University , Guangzhou 510632, China
| | - ShuJia Li
- Department of Chemistry, College of Chemistry and Materials, Jinan University , Guangzhou 510632, China
| | - Yu Tang
- Department of Chemistry, College of Chemistry and Materials, Jinan University , Guangzhou 510632, China
| | - PeiYao Lu
- Department of Pharmacy, College of Pharmacy, Jinan University , Guangzhou 510632, China
| | - KaiTian Xu
- Department of Chemistry, College of Chemistry and Materials, Jinan University , Guangzhou 510632, China
| | - YuanMing Zhang
- Department of Chemistry, College of Chemistry and Materials, Jinan University , Guangzhou 510632, China
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10
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Convenient, scalable synthesis of 2-methyl-3-(3′,3′-carboxymethylpropyl)-1,4-naphthoquinone, the principal vitamin K urinary metabolite. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.11.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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11
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Balachandra B, Shanmugam S, Muneeswaran T, Ramakritinan M. Iodine catalyzed one-pot synthesis of highly substituted N-methyl pyrroles via [3 + 2] annulation and their in vitro evaluation as antibacterial agents. RSC Adv 2015. [DOI: 10.1039/c5ra11094g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new class of highly substituted pyrroles have been synthesized via a simple, fast, and efficient method using environmentally friendly iodine catalyzed [3 + 2] annulation.
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Affiliation(s)
- Biguvu Balachandra
- Department of Organic Chemistry
- School of Chemistry
- Madurai Kamaraj University
- Madurai – 625 021
- India
| | - Sivakumar Shanmugam
- Department of Organic Chemistry
- School of Chemistry
- Madurai Kamaraj University
- Madurai – 625 021
- India
| | - Thillaichidambaram Muneeswaran
- Department of Marine and Coastal Studies
- School of Energy, Environment and Natural Resources
- Madurai Kamaraj University
- Madurai – 625 021
- India
| | - Muthiah Ramakritinan
- Department of Marine and Coastal Studies
- School of Energy, Environment and Natural Resources
- Madurai Kamaraj University
- Madurai – 625 021
- India
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12
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The first iodine improved 1,3-dipolar cycloaddition: facile and novel synthesis of 2-substituted benzo[f]isoindole-4,9-diones. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.08.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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14
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Li YJ, Huang HM, Dong HQ, Jia JH, Han L, Ye Q, Gao JR. The Synthesis of Benzo[f]isoindole-1,3-dicarboxylates via an I2-Induced 1,3-Dipolar Cycloaddition Reaction. J Org Chem 2013; 78:9424-30. [DOI: 10.1021/jo401652k] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yu-Jin Li
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Huan-Ming Huang
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Hua-Qing Dong
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Jian-Hong Jia
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Liang Han
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Qing Ye
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Jian-Rong Gao
- State Key
Laboratory Breeding
Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
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15
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Li YJ, Huang HM, Ju J, Jia JH, Han L, Ye Q, Yu WB, Gao JR. Iodine mediated reaction of quinones and N-substituted amino esters to 2-substituted benzo[f]isoindole-4,9-diones. RSC Adv 2013. [DOI: 10.1039/c3ra44095h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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16
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Baglai I, Maraval V, Voitenko ZV, Duhayon C, Volovenko YM, Chauvin R. Versatile reactivity of 3-chloro-2-phenyl-isoindole-1-carbaldehyde: hydrolysis and alkylating rearrangement to 1-amino-4-isochromanones. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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17
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de Lucas NC, Corrêa RJ, Garden SJ, Santos G, Rodrigues R, Carvalho CEM, Ferreira SB, Netto-Ferreira JC, Ferreira VF, Miro P, Marin ML, Miranda MA. Singlet oxygen production by pyrano and furano 1,4-naphthoquinones in non-aqueous medium. Photochem Photobiol Sci 2012; 11:1201-9. [DOI: 10.1039/c2pp05412d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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18
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Unexpected reaction of 2-amino-1,4-naphthoquinone with aldehydes: new synthesis of naphtho[2,1-d]oxazole compounds. Tetrahedron 2011. [DOI: 10.1016/j.tet.2010.10.082] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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19
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Five-Membered Ring Systems. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/s0959-6380(11)22006-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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20
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