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| 1.
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Kaneko, Chikara ; Fujii, Harue ; Kawai, Shinji ; Hashiba, Kazuhiko ; Karasawa, Yoshio ; Wakai, Masue ; Hayashi, Reiko ; Somei, Masanori
概要:
Irradiation (≥300 nm) of methyl 2-phenyl-3, 1-benzoxazepine-5-carboxylate in an alcohol afforded the Z-isomer of methyl
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3-alkoxy-2-(2-benzamidophenyl)-acrylate as the major addition product. In contrast, thermal reaction of the oxazepine with a primary alcohol in the presence of triethylamine led to the exclusive formation of the corresponding E-isomer. The same kinds of Michael addition products were also obtained stereoselectively from 3, 1-benzoxazepines having an acetyl group at the 5-position under these conditions. The interrelation between the stereoisomers obtained from the oxazepine and an alcohol under these two conditions was established by photochemical equilibration, and the stereochemistry of the two isomers was determined by proton magnetic resonance spectroscopy. An explanation is proposed for the observed stereoselectivities in the two kinds (photochemical and thermal) of reactions.
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| 2.
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Kaneko, Chikara ; Naito, Toshihiko ; Hashiba, Marimi ; Fujii, Harue ; Somei, Masanori
概要:
Two alkaloids, 1-methyl-4-(3-methylbut-2-enyloxy)-2-quinolone (revenine : IIc) and 4-methoxy-1-methyl-2-quinolone (IIa), were synthesized by means of a photochemical rearrangement reaction of the corresponding
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4-alkoxy-2-methylquinoline 1-oxide (Ic and Ia), which were conveniently prepared from 4-chloro-2-methylquinoline 1-oxide (XVII), which in turn is readily obtainable from 2-methylquinoline 1-oxide via the 4-nitrated compound (XVIII). The mechanism of the photo-rearrangement reaction of 4-alkoxy-2-methylquinoline 1-oxides (Ia-d) in methanol is discussed.
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| 3.
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Somei, Masanori ; Sato, Haruhiko ; Komura, Naoko ; Kaneko, Chikara
概要:
金沢大学大学院自然科学研究科生理活性物質科学<br />金沢大学薬学部
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| 4.
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Kaneko, Chikara ; Naito, Toshihiko ; Momose, Yu ; Shimomura, Naoyuki ; Ohashi, Tetsuo ; Somei, Masanori
概要:
Cyclopentane ring annelation methods for 2-pyridone derivatives are provided by cyclobutane ring expansion of 1, 2-dihydrocyclobuta [c] pyridin-3 (4H)-ones having an appropriate function at the l-position. Since the latter compounds are
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readily accessible from 4-alkoxy-2-pyridones via our two-step procedure (Kaneko-Naito method), the methods seem to have wide applicability for the synthesis of cyclopenta [c] pyridines.
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| 5.
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Somei, Masanori ; Karasawa, Yoshio ; Shoda, Toshiya ; Kaneko, Chikara
概要:
A convenient synthesis of 5-substituted isocoumarin derivatives, such as 5-nitroisocoumarin (2), 5-aminoisocoumarin (8), 3, 4-dihydro-3-methoxy-5-nitroisocoumarin (3), and 5-amino-3,
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4-dihydro-3-methoxyisocoumarin (10), from 2-methyl-3-nitrobenzoic acid (1) is reported. Several synthetic routes to methyl indole-4-carboxylate (9) from methyl 2-methyl-3-nitrobenzoate (4) directly or via these isocoumarins (8 and 10) are also presented.
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| 6.
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Kaneko, Chikara ; Fujii, Harue ; Kawai, Shinji ; Yamamoto, Atsushi ; Hashiba, Kazuhiko ; Kimata, Toshihiko ; Hayashi, Reiko ; Somei, Masanori
概要:
A novel photochemical ring-contraction reaction of 5-unsubstituted 3, 1-benzoxazepines and their 5-halogeno or carboxyl
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derivatives to yield 3-formylindoles in an aprotic solvent is reported. This ring contraction was successfully extended to oxazepines having an alkoxycarbonyl function at the 5-position to give the indoles having this function at the 3-position. Though most of the oxazepines underwent the ring-contraction reaction only on irradiation at 254 nm, 5-carboxy derivatives or their esters afforded the ring-contraction products even at ≥ 300 nm. The intermediacy of 3H-indole species in these photochemical ring-contraction reactions was demonstrated by the isolation of methyl 3-acetyl-2-phenyl-3H-indole-3-carboxylate during the photolysis of methyl 4-methyl-2-phenyl-3, 1-benzoxazepine-5-carboxylate. It was found that this 3H-indole afforded methyl 6-and 4-acetyl-2-phenyl-indole-3-carboxylates upon further irradiation. The mechanism of this acetyl migration is discussed based on the result of the photochemical acetyl migration of methyl 1-acetyl-2-phenylindole-3-carboxylate.
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| 7.
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Somei, Masanori ; Inoue, Satomi ; Tokutake, Shoichi ; Yamada, Fumio ; Kaneko, Chikara
概要:
Various 1-hydroxyindoles carrying a nitro, methoxycarbonyl, or benzyloxy group at the 4 position were prepared by the co
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ntrolled reduction of 6-substituted trans-β-dimethylamino-2-nitrostyrenes with either aqueous titanium (III) chloride or zinc in aqueous ammonium chloride. The stability of 4-substituted 1-hydroxyindoles decreased in the following order : 4-nitro-»4-methoxycarbonyl->4-benzyloxy-1-hydroxyindole. This result clearly indicates that an electron-withdrawing group at the 4-position can stabilize the 1-hydroxyindole structure. It was also found that 4-hydroxy-and 4-benzyloxy-indole were readily accessible by the reduction of 6-benzyloxy-2-nitrophenyl acetaldehyde. A unique route to 4-or 7-aminoindole from cinnoline is also described.
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| 8.
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Somei, Masanori ; Tokutake, Shoichi ; Kaneko, Chikara
概要:
The first syntheses of 6, 6a, 7, 8, 9, 9a-hexahydro-and 6, 6a, 9, 9a-tetrahydro-2H-isoindolo [4, 5, 6-cd] indoles are described. The preparation of 1, 3, 4, 5-tetrahydrobenz [cd] indole derivatives is also included.
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| 9.
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Somei, Masanori ; Yamada, Fumio ; Kurauchi, Takashi ; Nagahama, Yoshiyuki ; Hasegawa, Masakazu ; Yamada, Koji ; Teranishi, Sakiko ; Sato, Haruhiko ; Kaneko, Chikara
概要:
Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a),
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bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported.
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