- Total synthesis of maesanin and analogues
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An efficient total synthesis of maesanin and related quinones is reported, through direct alkylation of 1,2,4,5-tetramethoxybenzene with alkylbromides, followed by oxidation with ceric ammonium nitrate (CAN) which provokes formation of the quinone and dep
- Poigny, Stephane,Guyot, Michele,Samadi, Mohammad
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p. 14791 - 14802
(2007/10/03)
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- Synthesis of Natural Compounds with Alkyl-methoxy-1,4-benzoquinone Structure
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The 1,4-benzoquinones 1-7 occurring in various plants and having interesting biological properties have been synthesized from the tetrahydropyranyl ethers 17 and 21.Reaction with n-butyllithium gave selectively the ortho-lithiated compounds.These could be alkylated with the haloalkenes 13-16 and haloalkanes to give the substituted phenols 18-20 and 22-25 in high yield after methanolysis.Alkylations of the methoxyisopropylether 8 of 10-undecyn-1-ol with bromobutane and bromohexane gave 9 and 10.These alkynols could be selectively hydrogenated with Lindlar-Palladium catalyst to give the (Z)-alkenols 11 and 12 which could be converted into the bromoalkenes 13, 14 and the iodoalkenes 15, 16.Oxidation of the phenols 18-20 and 22-25 with molecular oxygen in the presence of salcomine as catalyst produced the substituted 1,4-benzoquinones 1-3 and 26-29 in high yield.Selective hydrolysis with perchloric acid converted 26-29 into the natural products 4-7. - Key Words: Tetrahydropyranyl-ethers / ortho-Lithiation / ortho-Alkylation / 1,4-Benzoquinones, alkyl-methoxy- / 1,4-Benzoquinones, alkyl-hydroxy-methoxy-
- Pfeifer, Jochen,Gerlach, Hans
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p. 131 - 138
(2007/10/02)
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- 1,4-benzoquinone derivatives and benzene derivatives, and process for preparing the same
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1,4-Benzoquinone derivatives and benzene derivatives having cerebral- and cardiac-blood flow improving activities and preventive activities of cerebral ischema with low toxicities, and thus are useful as activators for cardiac and cebral metabolisms, curing agents for heart failure, cardiac and cerebral blood flow improving agents, as well as anti-allergic agents for slow reacting allergy (IV-type allergy).
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- Naturally occurring 5-lipoxygenase inhibitor. II. Structures and syntheses of ardisianones A and B, and maesanin, alkenyl-1,4-benzoquinones from the rhizome of Ardisia japonica
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New alkenyl-1,4-benzoquinones, ardisianones A (1) and B (2), and the known maesanin (3) as 5-lipoxygenase inhibitors have been isolated from the rhizome of Ardisia japonica. Their structures have been elucidated as 2-methoxy-6-[(Z)-10'-pentadecenyl]-1,4-benzoquinone and 5-hydroxy-2-methoxy-6-[(Z)-8'-tridecenyl]-1,4-benzoquinone, respectively, on the basis of spectroscopic data and chemical degradation. Ardisianone A (1), maesanin (3) and belamcandol A (7) have been synthesized starting from belamcandol B (6), readily prepared by Wittig reaction between 9-(2-tetrahydropyranyloxy)nonanal and 3,5-dimethoxybenzyltriphenylphosphonium bromide followed by selective demethylation with sodium thioethoxide.
- Fukuyama,Kiriyama,Okino,Kodama,Iwaki,Hosozawa,Matsui
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p. 561 - 565
(2007/10/02)
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- ISOLATION, STRUCTURE AND SYNTHESIS OF MAESANIN, A HOST DEFENSE STIMULANT FROM AN AFRICAN MEDICINAL PLANT MAESA LANCEOLATE
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The isolation, characterization and an efficient synthesis of maesanin 1, a host defense stimulant isolated from an African medicinal plant Maesa lanceolate, is reported.
- Kubo, Isao,Kim, Mujo,Ganjian, Iraj,Kamikawa, Tadao,Yamagiwa, Yoshiro
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p. 2653 - 2660
(2007/10/02)
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- ISOLATION, STRUCTURE AND SYNTHESIS OF MAESANIN, A HOST DEFENSE STIMULANT FROM AN AFRICAN MEDICINAL PLANT MAESA LANCEOLATA
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The isolation, characterization and an efficient synthesis of maesanin 1, a host defense stimulant isolated from an African medicinal plant Maesa lanceolata is reported.
- Kubo, Isao,Kamikawa, Tadao,Miura, Iwao
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p. 3825 - 3828
(2007/10/02)
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