1988 Fiscal Year Final Research Report Summary
Synthesis of an antitumor active chelerythrine type alkaloid using Claisen rearrangement of a propargyl ether
| Project/Area Number |
61570992
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Chemical pharmacy
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| Research Institution | Chiba University |
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Principal Investigator |
ISHII Hisashi Professor, Faculty of Pharmaceutical Sciences, Chiba University, 薬学部, 教授 (70009166)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKAWA Tsutomu Research Associate, Faculty of Pharmaceutical Sciences, Chiba University, 薬学部, 助手 (20114233)
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| Project Period (FY) |
1986 – 1988
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| Keywords | synthesis / antitumor active alkaloid / Claisen rearrangement / furan ring cleavage / propargy ether |
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| Research Abstract |
1. Claisen Rearrangement of Aryl Propargyl Ether in the Presence of CsF: We found that Claisen rearrangement of the propargyl ether (1) in the presence of CsF , easily prepared, gave only the furan (3) but not the pyran (2) . This new reaction was examined in detail using the -naphthol derivative (4). The following facts were found on formation of a furan ring: (a) The best solvent was PHNET_2. (b) Other additives ex-cept CsF could not act. (c) A catalytic amount of CsF was enough, but practically about equimolar amount of it was needed. Heating 5__-, 6__- and the acetal of 7__- in PhNEt_2 containing CsF gave the corresponding furans in good yields, respectively, indicating generality of the reaction.
KA
2. Cleavage of the Furan Ring: The furan (8) derived from 7__- was used as a model compound for cleavage reaction of a furan ring. Successive treatment of 8__- with a stoichiometric amount of OsO_4, NaIO_4, and dil. NaHCO_3 aq. provided the desired salicylaldehyde (9) in satisfactory yield.
3. Synthesis of Chelerythrine (11): The aldehyde (10) was prepared from 3__- using the method mentioned adove. Treatment of the methyl ether of 10__- with TsOH resulted in deprotection and cyc-lization to give chelerythrine (11). We succeeded in synthesizing a chelerythrine type alkaloid.
KA
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