- THE CHEMISTRY OF 1-HYDROXYINDOLE DERIVATIVES: NUCLEOPHILIC SUBSTITUTION REACTIONS ON INDOLE NUCLEUS
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Nucleophilic substitution reactions were newly found to occur generally in the chemistry of 1-hydroxyindole derivatives.Its application to the synthesis of a phytoalexin, brassicanal A, is reported.
- Somei, Masanori,Kawasaki, Toshiya,Fukui, Yoshikazu,Yamada, Fumio,Kobayashi, Tetsuya,et al.
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- A convenient synthesis of the cruciferous phytoalexins brassicanal A and brassilexin by mimicry of a fungal detoxification pathway
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The cruciferous phytoalexin brassilexin 3 has been synthesized in four steps from indoline-2-thione via 3-(aminomethylene)indole-2-thione 2, a metabolic intermediate of the detoxification pathway of the phytoalexin cyclobrassinin 1; in addition, the phytoalexin brassicanal A 8 has been synthesized in two steps from 2-indolinethione.
- Pedras, M. Soledade C.,Okanga, Francis I.
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- Biotransformation of the Brassica Phytoalexin Brassicanal A by the Blackleg Fungus
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The biotransformation of the brassica phytoalexin brassicanal A by the blackleg fungus [Leptosphaeria maculans (Desm.) Ces. et de Not., asexual stage Phoma lingam (Tode ex Fr.) Desm] was investigated. Three main biotransformation products were detected and isolated; their chemical structures were determined by spectroscopic methods and concomitant synthesis. Additionally, the antifungal activities of brassicanal A and its biotransformation products were compared. Overall, the biotransformation pathway suggests that the blackleg fungus has enzymes to carry out this biotransformation different from those involved in the biotransformation of the brassica phytoalexin brassinin.
- Pedras, M. Soledade C.,Khan, Abdul Q.
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- Nucleophilic substitution reaction of 1-methoxyindole-3-carbaldehyde
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1-Methoxyindole-3-carbaldehyde is proved to be a versatile electrophile and reacts regioselectively at the 2-position with various types of nucleophiles providing 2-substituted indole-3-carbaldehydes.
- Yamada, Fumio,Shinmyo, Daisuke,Nakajou, Masahiro,Somei, Masanori
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- Strategies of cruciferous pathogenic fungi: Detoxification of the phytoalexin cyclobrassinin by mimicry
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The remarkable metabolism of the cruciferous phytoalexin cyclobrassinin by the phytopathogenic root rot (Rhizoctonia solani Kuhn) and blackleg [Phoma lingam (Tode ex Fr.) Desm., asexual stage of Leptosphaeria maculans (Desm.) Ces. et de Not.] fungi is reported. It was established that R. solani metabolized and detoxified cyclobrassinin via the phytoalexin brassicanal A, which was further transformed into nontoxic products. Detoxification of cyclobrassinin in P. lingam avirulent isolate unity occurred via the phytoalexin brassilexin, whereas the detoxification in P. lingam virulent isolate BJ 125 occurred via the phytoalexin dioxibrassinin. The chemistry involved in the structure determination of the intermediates of these three apparently different pathways and their antifungal activities are described. In addition, efficient syntheses of both phytoalexins brassicanal A and brassilexin by mimicry of the fungal biotransformation route are reported. Implications of these unprecedented transformations are discussed.
- Pedras, M. Soledade C.,Okanga, Francis I.
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- Syntheses of wasabi phytoalexin (methyl 1-methoxyindole-3-carboxylate) and its 5-iodo derivative, and their nucleophilic substitution reactions
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A simple synthetic method for methyl 1-methoxyindole-3-carboxylate, a phytoalexin isolated from Wasabia japonica, syn. Eutrema wasabi, and its 5-iodo derivative is reported. They underwent nucleophilic substitution reactions selectively at the 2-position.
- Somei, Masanori,Tanimoto, Asuka,Orita, Hitomi,Yamada, Fumio,Ohta, Toshiharu
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p. 425 - 432
(2007/10/03)
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- Derivatives of thiourea and thiosemicarbazide. Structure, transformations, and pharmacological activity: VII. Synthesis of 2-mercaptopyrimido[4,5-b]indole and 2-mercaptoindole-3-carbaldehyde derivatives
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2-Mercaptopyrimido[4,5-b]indole and 2-mercaptoindole-3-carbaldehyde derivatives were synthesized for the first time by reaction of 2-imino-9H-1,3-thiazino[6,5-b]indole with alkyl halides in alkaline medium. The alkylation is preceded by transformation of the thiazine ring into pyrimidine and cleavage of the latter with addition of water molecule and elimination of cyanamide. Attempts to obtain 2-mercaptopyrimido[4,5-b]indole or its 5-methyl derivative by cyclization of N-(2-oxo-2,3-dihydroindol-3-ylmethylene)-thiourea or its S-methyl derivative were unsuccessful. N-(2-Oxo-2,3-dihydroindol-3-ylmethylene)thiourea underwent cleavage of the C=N bond in the side chain.
- Tomchin,Marysheva
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p. 1060 - 1068
(2007/10/03)
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