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Mashiko T, Shingai Y, Sakai J, Adachi S, Matsuzawa A, Kamo S, Sugita K. Enantioselective Total Syntheses of (+)-Ganocin A and (-)-Cochlearol B. Org Lett 2023; 25:8382-8386. [PMID: 37955425 DOI: 10.1021/acs.orglett.3c03572] [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: 11/14/2023]
Abstract
Herein, we report the total syntheses of (+)-ganocin A and (-)-cochlearol B, featuring pentacyclic skeletons, in optically active forms. We utilized asymmetric Corey-Bakshi-Shibata reduction, phenolic oxidative cyclization, the intramolecular radical cyclization-benzylic oxidative cyclization sequence, and intramolecular [2 + 2] photocycloaddition. These key steps enabled enantioselective access with the longest linear sequence of 17 steps and 9% overall yield for (+)-ganocin A and with 16 steps and 9% overall yield for (-)-cohlearol B.
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Affiliation(s)
- Tomoya Mashiko
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Yuta Shingai
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Jun Sakai
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Shinya Adachi
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Akinobu Matsuzawa
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Shogo Kamo
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Kazuyuki Sugita
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
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Mashiko T, Shingai Y, Sakai J, Kamo S, Adachi S, Matsuzawa A, Sugita K. Total Synthesis of Cochlearol B via Intramolecular [2+2] Photocycloaddition. Angew Chem Int Ed Engl 2021; 60:24484-24487. [PMID: 34533883 DOI: 10.1002/anie.202110556] [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] [Received: 08/06/2021] [Revised: 09/15/2021] [Indexed: 11/12/2022]
Abstract
Herein, we describe the first total synthesis of cochlearol B, a meroterpenoid natural product featuring a 4/5/6/6/6-fused pentacyclic structure. Key steps, oxidative cyclization and subsequent intramolecular [2+2] photocycloaddition, which constructed the pentacyclic structure in highly stereoselective manner, allowed efficient access to cochlearol B with the longest linear sequence of 16 steps, and in 9 % overall yield. Single-crystal X-ray crystallographic analysis clearly confirmed the stereochemistry of cochlearol B.
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Affiliation(s)
- Tomoya Mashiko
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Yuta Shingai
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Jun Sakai
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Shogo Kamo
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Shinya Adachi
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Akinobu Matsuzawa
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Kazuyuki Sugita
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
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Mashiko T, Shingai Y, Sakai J, Kamo S, Adachi S, Matsuzawa A, Sugita K. Total Synthesis of Cochlearol B via Intramolecular [2+2] Photocycloaddition. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Tomoya Mashiko
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
| | - Yuta Shingai
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
| | - Jun Sakai
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
| | - Shogo Kamo
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
| | - Shinya Adachi
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
| | - Akinobu Matsuzawa
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
| | - Kazuyuki Sugita
- Department of Synthetic Medicinal Chemistry Faculty of Pharmaceutical Sciences Hoshi University 2-4-41 Ebara, Shinagawa-ku Tokyo 142-8501 Japan
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Hino K, Kitase A, Satoh Y, Fujiwara D, Yamaguchi Y, Korenaga M, Shingai Y, Konishi T, Yamashita S, Uchida K, Mori K, Hanada H, Kodama T, Nukui K, Okita K. Interferon retreatment reduces or delays the incidence of hepatocellular carcinoma in patients with chronic hepatitis C. J Viral Hepat 2002; 9:370-6. [PMID: 12225332 DOI: 10.1046/j.1365-2893.2002.00366.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Inhibition of hepatocarcinogenesis is a crucial issue in treating chronic hepatitis C patients, especially those who do not respond completely to interferon therapy. Interferon has been reported to reduce the incidence of hepatocellular carcinoma (HCC) not only in sustained virological responders but also in transient biochemical responders. However, the incidence of HCC increases in 5 years or more after interferon therapy in transient biochemical responders. The aim of this study is to assess whether interferon retreatment reduces the incidence of HCC in chronic hepatitis C patients in whom hepatitis C virus was not eradicated during initial interferon therapy. We enrolled 309 patients who were not sustained virological responders after initial interferon treatment consisting of a total dose of more than 250 megaunits of interferon and were followed for more than 2 years after treatment. Ninety-nine patients received interferon retreatment and 210 did not. Two courses of interferon therapy were administered in 84, three courses in 14 and five courses in one. The incidence of HCC was compared between patients with retreatment and those without. In the clinical characteristics, retreated patients were younger and followed up for a longer time period. The cumulative incidence of HCC was significantly lower in retreated patients. In multivariate analysis, patients' age (P=0.018) and the number of courses of interferon therapy (P=0.022) were independently associated with HCC incidence. These results suggest that interferon retreatment reduces or delays the incidence of HCC in chronic hepatitis C patients who did not completely respond to initial therapy.
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Affiliation(s)
- K Hino
- Department of Gastroenterology and Hepatology, Yamaguchi University, School of Medicine, Ube, Japan.
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Oka S, Noda K, Murata M, Shingai Y, Harada H, Tada M, Matsuda K, Yanai H, Kinukawa K, Okazaki Y. [The histochemical and biochemical studies on gamma-glutamyl transpeptidase in human gastric cancer]. Nihon Shokakibyo Gakkai Zasshi 1985; 82:2538-43. [PMID: 2868139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Yasunaga M, Okita K, Sanuki K, Murata M, Ogino M, Shingai Y, Kado U, Nawata H, Yoshida T, Konishi T. [Influence of H2-receptor antagonists to liver blood flow in rat]. Nihon Shokakibyo Gakkai Zasshi 1985; 82:1348-53. [PMID: 2863407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Ogino M, Okita K, Nawata H, Yasanaga M, Shingai Y, Kado Y, Oda M, Ezaki T, Matsuda S, Ando K. [Purification of a new glutathione S-transferase from rat liver cytosol and its significance during hepatocarcinogenesis]. Nihon Shokakibyo Gakkai Zasshi 1984; 81:1012-8. [PMID: 6748311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Hanta T, Okita K, Matsuda S, Konishi T, Yasunaga M, Kado Y, Nawata H, Ogino M, Shingai Y, Fukumoto Y. [A case of fulminant hepatitis developing in a HBsAG carrier after chemotherapy of malignant lymphoma]. Nihon Shokakibyo Gakkai Zasshi 1984; 81:1089-93. [PMID: 6748319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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