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| 1.
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Fujii, Tozo ; Yoshifuji, Shigeyuki ; Yoshida, Kiyoshi ; Ohba, Masashi ; Ikegami, Shiro ; Kirisawa, Makoto
概要:
The alkaline ferricyanide oxidation of the quaternary pyridinium salts (Ia-g) furnished pairs of the isomeric 2-pyridones (IIa-g) and 6-pyridones (IIIa-g) in good total yields. In all cases, the oxidation at the 2-position was much
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favored over that at the 6-position. The effect of the aryl group in the N-aralkyl chain on the orientation of the oxidation seemed to be negligibly small regardless of the number of the methylene groups separating the aryl group from the nitrogen. The extent of the 6-oxidation was slightly increased as the alkyl group at the 3-position was changed from the methyl to the ethyl group. The nuclear magnetic resonance spectra of these pyridones were measured in deuteriochloroform, carbon tetrachloride, and benzene-d_6. On the basis of the results summarized in Tables III-VI, the effects of the aryl group and the number of the methylene groups in the N-substituent on the chemical shifts for the pyridone-ring and neighboring group protons are discussed.
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| 2.
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Fujii, Tozo ; Yoshifuji, Shigeyuki ; Hatanaka, Yasumaru ; Yoshida, Kiyoshi ; Ohba, Masashi ; Yamada, Koichiro ; Ohkuma, Mihoko ; Shinoda, Hirotaka ; Mizuno, Denichi
概要:
Seventy-four compounds related to lactams and pyridones were synthesized and their anti-tumor activity was examined using Ehrlich carcinoma cells. 4-(2-Piperidyl) butyric acid hydrochloride was found to have some anti-tumor
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effect on the solid type of Ehrlich carcinoma cells, but no other substances were found to be effective. Correlation between the anti-tumor activity and structure of the tested compounds still remains uncertain.
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| 3.
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Fujii, Tozo ; Yoshida, Kiyoshi ; Ohba, Masashi ; Yoshifuji, Shigeyuki
概要:
The mercuric acetate-(ethylenedinitrilo) tetraacetic acid oxidation of 1-(3,4-dimethoxyphenyl)-2-(3-substituted piperidino) ethanols (7c-f), which carry the n-butyl, isopropyl, benzyl, and phenyl group as the 3-substituent in
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the piperidine ring, has been found to produce the corresponding 2- (8c-f) and 6-piperidones (12c-f) in good yields in ratios of 41 : 59,29 : 71,26 : 74,and 15 : 85. It is suggested that the 3-substituents exert both steric and electronic effects. The structures of the lactam alcohols (8c-f, 12c-f) have been confirmed by the chemical correlation with the known pyridones (11c-f, 15c-f) through the lactams (10c-f, 14c-f). The starting piperidinoethanols (7c-f) have been synthesized from the 3-substituted pyridines (5c-f) by quaternization with 3,4-dimethoxyphenacyl bromide followed by catalytic and sodium borohydride reductions.
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| 4.
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Fujii, Tozo ; Ohba, Masashi ; Yoshifuji, Shigeyuki ; Kirihara, Makoto
概要:
In the alkaline ferricyanide oxidation at 32°of 3-substituted 1-(3,4-dimethoxyphenethyl) pyridinium bromides (type 3), t
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he hydroxymethyl, N, N-dimethylaminomethyl, carbamoyl, and 1,1-ethylenedithioethyl groups at the 3-position have been found to orient the oxidation to both the 2-(type 4) and the 6-position (type 5) in ratios of 70 : 30,26 : 74,50 : 50,and 4 : 96. The carboxyl or 1,1-ethylenedioxyethyl group at the 3-position has oriented the oxidation to the 6-position exclusively, and possible factors in determining the regioselectivity in the ferricyanide oxidation of the 1,3-disubstituted pyridinium salts are discussed. For preparation of additional pyridone derivatives, 1-(3,4-dimethoxyphenethyl)-5-carboxy-2(1H)-pyridone (5d) was esterified with methanolic hydrogen chloride to the methyl ester (5h), and 1-(3,4-dimethoxyphenethyl)-5-(1,1-ethylenedioxyethyl)-2 (1H)-pyridone (5e) was converted into the methyl ketone (5i) by acid hydrolysis. The structures of the pyridones (4a, b, c, f, 5a-i) thus prepared have assigned on the basis of their ultraviolet, infrared, and nuclear magnetic resonance spectra.
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| 5.
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Fujii, Tozo ; Yamada, Koichiro ; Minami, Shinzaburo ; Yoshifuji, Shigeyuki ; Ohba, Masashi
概要:
The first total synthesis of alangicine (3), an Alangium lamarckii alkaloid, has been achieved in the form of a racemic
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modification by means of an initial alkaline hydrolysis of the (±)-tricyclic ester 6 and succeeding steps proceeding through the intermediates (±)-7,(±)-10,and (±)-9. A parallel synthetic route starting with the (-)-tricyclic ester 6,derived from (+)-cincholoipon ethyl ester (8), produced the chiral target molecule (+)-3 with alangicine unequivocally established the structure and absolute stereochemistry of this alkaloid. The ^<13>C nuclear magnetic resonance spectra of (±)-alangicine (3) and the ipecac and Alangium alkaloid psychotrine (18) confirmed their endocyclic double bond structures in the dihydroisoquinoline moiety. Catalytic reductions of 11,(±)-12,and 15 using hydrogen and Pd-C were investigated, and the results have shown that hydrogenolysis of the benzyloxy group proceeds much faster than saturation of the endocyclic C=N bond.
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| 6.
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Fujii, Tozo ; Ohba, Masashi ; Yoshifuji, Shigeyuki
概要:
1-(3,4-Dimethyoxyphenyl)-2-(3-substituted piperidino) ethanols (3a-d), which carry the carbamoyl, methoxycarbonyl, acetyl, and 1,1-ethylenedioxyethyl group as the 3-substituent in the piperidine ring, have been prepared from
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3-substituted pyridines (type 1) through 1-(3,4-dimethoxyphenacyl) pyridinium bromides (type 2). In the mercuric acetate-EDTA oxidation of 3a-d, these 3-substituents have been found to orient the lactam carbonyl formation to the 6-position almost exclusively. It is suggested that the 3-substituents exert both steric and electronic effects.
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| 7.
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Fujii, Tozo ; Yoshifuji, Shigeyuki ; Ohba, Masashi
概要:
3,4-Dimethoxy, 3-benzyloxy-4-methoxy, 3,4,5-trimethoxy, 2-hydroxy-3,4-dimethoxy, and 2-benzyloxy-3,4-dimethoxy derivatives (3a-e) of phenacyl bromide have been prepared in 44-84% yields from the corresponding acetophenones by bromination
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with bromine in a mixture of ether and chloroform.
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| 8.
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Fujii, Tozo ; Ohba, Masashi ; Yoshifuji, Shigeyuki ; Akiyama, Shigeaki
概要:
In order to investigate the effect of an N-substituent on thermal cis-trans isomerization of the 5-ethyl-2-oxo-4-piperid
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ineacetic acid system, the N-alkyl analogs (±)-1b, c and (±)-2b, c and the N-(2-arylethyl) analogs (-)-1f, g, i and (+)-2f, g, i were separately heated neat at 180℃, and the propress of their cis-trans isomerization reactions was followed by determining the isomer ratios in the reaction mixtures according to the previously reported C-13 nuclear magnetic resonance spectroscopic method. It has been found that in all cases the reaction comes to equilibrium within 28-130 min, when the cis and trans isomers exist in a ration of 1 : 2. These results together with those obtained previously with the analogs (±)-1a, d, e, (-)-1h, (±)-2a, d, e, and (+)-2h indicate that a higher and/or bulkier N-substituent tends to decrease the rate of cis-trans isomerization of the 5-ethyl-2-oxo-4-piperidineacetic acid system, which is a useful synthon for the synthesis of benzo-[a] quinolizidine-type Alangium alkaloids. Among the substrates used in the present equilibration study, (±)-1b, c and (±)-2b, c were prepared from the corresponding N-unsubstituted lactam esters (±)-3 and (±)-7 by the"lactim ether method."
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| 9.
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Fujii, Tozo ; Yoshida, Kiyoshi ; Ohba, Masashi ; Mitsukuchi, Morihiro ; Tanaka, Izumi ; Yoshifuji, Shigeyuki ; Kirisawa, Makoto
概要:
The alkaline ferricyanide oxidation at 32°of 1-(3,4-dimethoxyphenethyl) pyridinium bromides (3c-f) carrying the n-butyl,
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isopropyl, benzyl, and phenyl group at the 3-position has been found to produce the corresponding 2-(4c-f) and 6-pyridones (5c-f) in ratios of 74 : 26,71 : 29,69 : 31,and 13 : 87. In the case of the 3-benzyl derivative (3e), 1-(3,4-dimethoxyphenethyl)-5-benzoyl-2 (1H)-pyridone (5g) has also been obtained in 1% yield. On the basis of the present and earlier data, possible factors in determining the orientation in the ferricyanide oxidation of 1,3-disubstituted pyridinium salts are discussed.
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| 10.
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Fujii, Tozo ; Ohba, Masashi ; Yoneyama, Kaoru ; Kizu, Hiroko ; Yoshifuji, Shigeyuki
概要:
A formal chiral synthesis of the Alangium alkaloid (-)-ankorine [(-)-6] has been accomplished in the form of the synthesis of the lactam phenol (+)-14 from the (+)-trans-lactim ether (+)-5 and 2-benzyloxy-3,4-dimethoxyphenacyl bromide
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through the intermediates (+)-10 and 11. A parallel sequence of conversions starting from the (-)-trans-lactim ether (-)-5 and proceeding through the intermediates (-)-10,24,(-)-14,(-)-15,26,(+)-27,and (+)-28 produced the enantiomer [(+)-6] of natural ankorine. For an alternative chial synthesis of (-)-6,ethyl cincholoiponate [(+)-19] was acetylated and the resulting N-acetyl derivative (+)-20-was oxidized with RuO_4 to give the 6-piperidone (+)-21,and 2-piperidone (-)-23 in 55% and 27% yields, respectively. The (-)-cis-lactim ether (-)-16,obtained by ethylation of (+)-21 with triethyl-oxonium fluoroborate, was then converted into (-)-13,a known precursor for the synthesis of (-)-ankorine [(-)-6], in good overall yield by a "lactim ether route, " which proceeded through (+)-15 and 12.
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