- 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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- 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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- Total synthesis of the host defense stimulant maesanin
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An efficient total synthesis of the host defense stimulant maesanin has been achieved by a route featuring a photochemical aromatic annulation as a key step.
- Danheiser, Rick L.,Cha, Don D.
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p. 1527 - 1530
(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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