12 research outputs found
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é沢倧åŠè¬åŠéšç 究課é¡/é åçªå·:X00090----457519ç 究æé(幎床):1979åºå
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±éåæäžéäœã®æ¹è¯åæãå®çŸãã.3.ãã®åå¿ããã¯ã¬ãªã·ãã¬ãã«ã«é©çšã,ç«äœååŠçã«çŽç²ãªéèŠåæäžéäœãåŸãããšã«æåã,埮éãã¯ã¬ãªã·ãã§ããã¯ã€ããã·ã³ã®å®çšçåæ,ã¯ã€ããããœã·ã³ã®æåã®åæãå¯èœã«ãã.4.ããã«ã°ãªã·ã³ã®ããã¯åå¿ã¯æ°Žã溶åªãšããå Žåã§ãçé
žæ°ŽçŽ ãããªãŠã ãçšããã®ãããããšãåãã£ã.ãã®ãããªåå¿æ¡ä»¶äžã§ã,è€çŽ ç°ã®ãšãŠåç©ãé»ååžåŒæ§åºããã€ãšãŠåãã³ãŒã³ãšã®åå¿ã¯æºè¶³ãã¹ãçµæãäžããªãã£ã.ããã«å¯ŸããŠ,ããã¿ã¬ã³ãç¡çœ®æãããã¯é»åäŸäžæ§åºãæãããšãŠåãã³ãŒã³ã§ã¯95-98%eeã®ç®çç©ãåç51-66%ã§çæãã.以äžã®çµæ,ãããã®æ¹æ³ãåç¬ã§ã¯Î², γ-äžé£œåã¢ããé
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åŠçŽåºŠã®é«ã(E)-2-(ã¢ãªãŒã«ããã«)ã°ãªã·ã³èªå°äœã®åªããçžè£çåææ³ãšãªãããšãå€æãã.We have developed two methods for synthesis of optically active (E) -2- (arylvinyl) glcine derivatives.(1) In the present investigation N-protected 3- (triphenylphosphonio) alaninates are shown to be useful for the Witting reaction only with aromatic aldehydes : isobutyralehyde, cyclohexanone, and benzophenone proved unsuitable for this reaction.(2) Improved synthesis of the optically pure key intermediate for the synthesis of hypermodified bases of phenylalanine transfer ribonucleic acids was achieved by the Wittig reaction employing N- (methoxycarbonyl) -3- (triphenylphosphonio) alaninate.(3) The Wittig reaction described above was successfully applied to the synthesis at the nucleoside level. Thus, the most probable alternatives for the hypermodified nucleoside of rat liver phenylalanine transfer ribonucleic acid was synthesized for the forst time.(4) For the Heck reaction between (S) -N- (benzyloxycarbonyl) vinylglycine and 4-iodoanisole in H_2O,NaHCO_3O was shown to be best of the bases tested from a viewpoint of optical yield.(5) Scope and limitations of the Heck reaction described above was established in the present study.Various (E) - (2-arylvinyl) glycines of 95-98% ee were obtained in highly stereoselective manners in 51-66% yields from phenyl, tolyl, anisyl, and naphthyl iodides. However, 2-, 3-, and 4-bromophenyl iodides provided the corresponding olefins of somewhat low optical purity (85-90% ee) in 30-51% yields ; iodobenzenes carying an electronwithdrawing 4-nitro or 4-acetyl group gave poor yields of products. Limited success was accomplished with iodides of heterocycles such as thiophene, imidazole, and imidazo [1,2-alpha] purin-9-ones.ç 究課é¡/é åçªå·:07557289, ç 究æé(幎床):1995 â 1996åºå
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å ±åŠç 究æïŒïŒ ïŒhttps://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-07557289/075572891996kenkyu_seika_hokoku_gaiyo/ïŒãå å·¥ããŠäœ
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žãæ§æãã37äœã®ãã¯ã¬ãªã·ãã®æ§é ã¯,ããããã·ã¯ã€ããã³ã®3-β-D-ãªããã©ãã·ã«äœã§ãããšæšå®ãããŠããã«ãããªã.æ¬ç 究ã¯,æšå®æ§é ã«çžåœãã2çš®ã®ãžã¢ã¹ãã¬ãªããŒãåæã,ãããã®æ§è³ªã粟æ»ããããšã«ãã£ãŠåœè©²ãã¯ã¬ãªã·ãã®çäœè©Šæããã®åé¢ã容æã«ã,ãã®æ§é ã決å®ããããšãç®çãšã,次ã®ãããªææãåŸã.1. β-ããããã·ã¯ã€ããã³ã®åææ³ãèžè¥²ããŠåœè©²ãã¯ã¬ãªã·ãã®åæãéæããããã«,åææ³ã®æ¹è¯ãæ€èšã,ååå
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žãžãšã¹ãã«ãžã®å€æã,ããªãžã³ååšäžãã¹ã²ã³ãçšããæ¹æ³ã«å€ããããšã«ãã£ãŠåçã®æ¹åã«æåãã.3. ç³éšãã·ãªã«åºã§ä¿è·ããçž®å3ç°æ§ã¢ã«ãããã«å¯ŸããŠæ¹è¯ãŠã£ããã£ããåå¿ãæå¹ã§ããããšã蚌æã,ç°ç¶çé
žãžãšã¹ãã«ãçµãŠç®çã®ãã¯ã¬ãªã·ãã®2çš®ã®ãžã¢ã¹ãã¬ãªããŒã®åæã«æåãã.次ã«,ãã®ãã¯ã¬ãªã·ãã®çž®å3ç°éšã®7äœçœ®æåºãš6äœçœ®æåºãå
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æ°ŽçŽ çµåãå¯èœãªçœ®æåºã¯æŽã«è»¢äœãä¿é²ãã.(1)An improved synthesis of the key intermediates for the synthesis of [R-(R*, S*)]- and [S-(R*, R*)]-beta-hydroxywybutines, the most probable structures for the minor base from rat liver tRNA^, has been achieved by the Wittig reaction between 1-benzyl-7-formylwye and the phosphorane derived from (R)- 2-[(methoxycarbonyl)amino]-3-(triphenylphosphonio)- propanoate, followed by methylation, 0S0_4 oxidation, and cyclo-condensation with COCl_2 in the presence of pyridine. (R*, R*)-beta-Hydroxywybutine and its diastereomer, which were required for the determination of the optical purity of the chiral bases by means of chiral HPLC, were conveniently prepared through pyrolysis of the cyclic carbonate followed by NaBH_4 reduction and catalytic hydrogenolysis. The samples of [R-(R*, S*)]- and [S-(R*, R*)-beta-hydroxywybutines were thus shown to be optically pure.(2)The synthesis at the nucleoside level started with the Vilsmeier reaction of 3-[2,3,5-tris-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]wye and proceeded through the Wittig reaction with (R)-2-[(methoxycarbonyl)-amino]-3-(triphenylphosphonio)propanoate, methylation with trimethyl-silyldiazomethane, 0s04 oxidation, cyclocondensation with triphosgene, and catalytic hydrogenolysis. Chromatographic separation of the resulting diastereomeric mixture and subsequent deprotection afforded the two desired nucleosides for the first time.(3)it has been revealed that the rate of isomerization of l-benzyl-4-methyl-4,9-dihydro- 1H-imidazo[1 ; 2-alpha]purin-9-ones in 0.1 M MeONa-MeOH at .25*C increases with increasing electron-withdrawing nature of the 7-substituent and that the reactivity is further promoted by the intramolecular hydrogen bond between the carbonyl group at the 9-position and the 7-substituent.ç 究課é¡/é åçªå·:09672140, ç 究æé(幎床):1997 â 1998åºå
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é沢倧åŠè¬åŠéš1. (E)-1-ãã³ãžã«ãŒ7-ãã«ãã«ã¯ã€ããªã¹ããŠé
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èŠãªåæäžéäœ(S)-(E)-1-ãã«ãžã«ãŒ7-(3-ã«ã«ãã¡ããã·ãŒ3-ã«ã«ãã¡ã€ããã·ã¢ãããŒ2-ãããã«)ã¯ã€ã®åææ³ãæ¹è¯ãã. ããªãã¡, 1-ãã³ãžã«ã¯ã€ãNaHCO_3ååšäžI_2ãšã®åå¿ã«ãã£ãŠå®¹æãã€é«åçã§1-ãã³ãžã«ãŒ7-ãšãŒãã¯ã€ãšã, ããã«ã°ãªã·ã³èªå°äœãšã®Heckåå¿ã«ãã£ãŠç®çãéãã. ãã®åå¿ã®æäœã¯éåžžã«ç°¡åãªã®ã§, ããã«éèŠäžéäœã®å€§éåæãå¯èœã«ãªã£ããã®ãšæããã. ããããªãã, äžæ¹ã®åæã§ããå
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修食塩åºã«å¯Ÿããæšçååç©7-(3-ã«ã«ãã¡ããã·ãŒ3-ã«ã«ãã¡ããã·ã¢ãããŒ2-ããããã·ããã«)ã¯ã€ã®(B,S)-åã³(S,S)-äœãåæããããšã«æåãã.4. ããã«åŸãæšçååç©ã®ååŠçæ§è³ªã®æ€èšåã³é¡èšå¡©åºã®çäœè³æããã®åé¢ã¯çŸåšç¶è¡äžã§ãã.1. The synthesis of a model compound for the title fluorescent base has been established by a series of the reactions: the Witting reaction between 1-benzy1-7-(triphenylphosphoniomethyl)wye and isobutyraldehyde, oxidation with OsO_4, cyclic carbonate formation by treatment with (COCL)_2, and catalytic hydrogenolysis over Pd-C.2. The Heck reaction of 1-benzy1-7-iodowye with (S)-N-(methoxycarbonyl)vinylglycine followed by methylation has provided an improved method for the synthesis of\u27(S)-(E)-1-benzy1-7-[3-methoxycarbonyl-3-(methoxycarbonyl)amino-1-butenyl]wye, the key intermediate for the synthesis of the target compounds. Oxidation of the intermediate with OsO_4 gave a pair of the diastereomers of the diols and the (S,S,S) configurations were assigned to the major product by means of X-ray analysis. According to the model experiments mentioned above, the diols were transformed into [R-(R^*,S^*)]- and [S-(R^*,R^*)]-hydroxywybutine, two alternatives for the title base.3. Investigation of the chemical properties of the isomers of hydroxywybutine and isolation of the base from natural sources are in progress.ç 究課é¡/é åçªå·:61570998, ç 究æé(幎床):1986 â 1987åºå
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žããåé¢ãããã¯ã€ããã·ã³ã®å æ°Žå解é床ãšåçšåºŠã§ãã£ããååç©1ã®ããªã¢ã»ãã«äœã¯ãã®ãžã¢ã¹ãã¬ãªã-ãšé«é液äœã¯ãããã°ã©ãã£-ãªã©ã«ãã£ãŠæçã«åºå¥ããããšãã§ããã®ã§ãã¯ã€ããã·ã³ã®åé¢åå®ã¯å®å®ãªããªã¢ã»ãã«äœã§è¡ãªãã®ãåŸçã§ããããã®ç·ã«æ·»ã£ãäœæ¥ãéæç¶è¡äžã§ãããWe had already achieved the synthesis of wybutine, the base of the title compound, wybutosine, by means of the Wittig or the, Heck reaction as a key step. Neither similar Wittig approach nor the modified procedure effected the synthesis of our target compound, 3-beta-D-ribofuranosylwye (1). On the other hand, the Heck reaction at the nucleoside level successfully afforded 1. This product, however, proved to be contaminated by its diastereomer. In order to develop a stereoselective synthesis of 1, we attempted several recent methods of C-C bond forming reactions as well as modification of the Heck reaction. Because none of them gave a positive result, we focused on separation of (S)-4,9-dihydro-alpha-[(methoxycarbonyl)amino]-4,6-dimethyl-9-oxo-3-(2,3,5-tri-omicron-acetyl-beta- D-ribofuranosyl)-3H-imidazo[1,2-alpha]purine-7-butanole acid (2), a precursor for the synthesis of 1, from its diastereomer by high-performance liquid chromatography. The separation was attained by use of a reversed-phase system [acetonitrile-0.02 M aqueous sodium dihydrogen phosphate (15:85, v/v)]. Compound 2 was treated with trimethyl- silyldiazomethane followed by deacetylation to afford stereochemically pure I for the first time. Compound 1 thus obtained underwent unusually fast hydrolysis at the N-glycosidic bond and the rate was of the same order of magnitude as that reported for wybutosine. Because 2\u27,3\u27,5\u27-tri-omicron-acetyl derivative of 1 proved much more stable than 1, isolation and identification of wybutosine should be done through its triacetate.ç 究課é¡/é åçªå·:63570988, ç 究æé(幎床):1988 â 1989åºå
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žãžãšã¹ãã«ã®éžæçåææ³ã®ç¢ºç«ãç®æããå®éšãé²ããŠãããThe synthesis of the title compounds involves the Witting reaction or the Heck reaction, and transformation of the 1,2-diol compound to the cyclic carbonate, as the key steps. Although the Witting reaction using (R)-[2-carboxy-2-[(methoxycarbonyl)amino]ethyl]triphenylphosphonium chloride (1) had not afforded the desired product at the nucleoside level, we obtained the key intermediate by employing 7- formyl-3-[2,3,5-tri-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]wye and the inner salt 2 derived from 1. We also demonstrated that the product obtained in the Wittig reaction between 2 and piperonal was optically pure. For the synthesis of compounds labelled with an isotope, several phosphonium salts (type 2) differently protected at the amino group were synthesized. Among them benzyloxycarbonyl and tert-butoxycarbonyl compounds gave positive results in the Wittig reaction with piperonal; the former was better in view of the yield. On the other hand N-(tert-butoxycarbonyl)vinylglycine was better than the benzyloxycarbonyl compound for the Heck reaction with 1-benzyl- 7-iodowye. Thus we established two stereoselective methods of preparing optically active (E)-(2-arylvinyl)glycine derivatives.It was necessary for us to elucidate the mechanism of the formation of the cyclic carbonates in the reaction of 1,2-glycols and oxalyl chloride for improvement of the yield of the target nucleosides. We then studied the reactions of oxalyl chloride with various 1,2- glycols; the results allow us to explain the formation of the carbonates in terms of stereoelectronically controlled cleavage of the tetrahedral intermediates. According to the proposed mechanism we may have a chance of finding how to prepare exclusively the carbonates or the oxalates, whichever we want. Further investigation along this line is under progress.ç 究課é¡/é åçªå·:03670997, ç 究æé(幎床):1991 â 1992åºå
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žãžãšã¹ãã«ã®äŸå€çãªå®å®æ§ã説æãåŸããã®ã§ãã£ã.We have already disclosed that oxalyl chloride reacts with acyclic 1,2-glycols in tetrahydrofuran in the presence of triethylamine to afford a different type of compound as a major product, depending on the structure of the glycol : unsubstituted, monosubstituted, and erythro-disubstituted ethylene glycols provided the cyclic oxalates or polymeric oxalates, while the threoisomers and pinacol afforded the cyclic carbonates.1.The only exception we found was trans-cyclohexane-1,2-diol, which exclusively afforded the cyclic oxalates. This reaction probably proceeded through the tetrahedral intermediate with a boat form, avoiding steric interference between the bridge-head hydrogen and carbonyl oxygen.2.The dramatic reversal of the product ratio was realized in the reaction with pinacol or the threo-compounds by the use of pyridine instead of triethylamine to afford the cyclic oxalates. 1,1\u27-Oxalyldiimidazole was found to be a good choice for the exclusive formation of the cyclic oxalates. The formation of the polymeric oxalates from the erythro-compounds was completely suppressed by the use of 2,4,6-collidine.3.The cyclic oxalates thus obtained underwent hydrolytic cleavage of the acyl-alkoxy linkage to afford the monoester of oxalic acid at pH 5 at the rate of 200-1000 times faster than the cyclic oxalate of pinacol. The three-dimensional structure elucidated by X-ray crystal analysis shows that the carbonyl carbons of the cyclic oxalate of pinacol are effectively blocked by two of the four methyl groups.ç 究課é¡/é åçªå·:06672095, ç 究æé(幎床):1994 â 1995åºå
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Reactions of oxalyl chloride with 1,2-cycloalkanediols in the presence of triethylamine
The relationship between the product patterns and the configurations of 1,2-cycloheptane- and 1,2-cyclooctanediols 9 in the cyclocondensations with oxalyl chloride in the presence of tricthylamine at 0°C has been shown analogous to that obtained for 1,2-disubstituted acyclic ethylene glycols 1: cis-1,2-cyclooctanediol (9f) produced the cyclic oxalate 14f as the major product, while trans-1,2-cycloheptanediol (9e) and trans-1,2-cyclooctanediol (9g) formed the cyclic carbonates 12e, g as the major products. On the other hand, the cyclic oxalates 14a-d were formed as the major products from 1,2-cyclopentane- and 1,2-cyclohexanediols regardless of the configuration. These results can be accounted for by assuming the boat-like transition states for cyclizations of the half esters of comparatively rigid five- and six-membered diols 9a-d. The cyclic oxalates 14a, c may be directly formed through the resulting tetrahedral intermediates from cis-diols (9a, c), and the cyclic carbonates 12a, c as the minor products after ring inversion of the tetrahedral intermediates. The tetrahedral intermediates from the trans-isomers 9b,d cannot undergo ring inversion, producing no traces of the cyclic carbonates 12b,d. © 2002 Pharmaceutical Society of Japan
Efficient synthesis and hydrolysis of cyclic oxalate esters of glycols
Based on the mechanism postulated for the formation of the cyclic carbonates 3 in the reactions of glycols 1 with oxalyl chloride in the presence of triethylamine, we present here three efficient syntheses of the cyclic oxalates 2 of various glycols 1 by controlling the formation of 3: replacement of the base by pyridine markedly diminishes yields of 3 in all reactions, realizing dramatic reversals of the product ratios in the reactions with the (R*,R*)-compounds 1g-i, q, r and pinacol (1k); although considerable amounts of the oxalate polymers are formed in the reactions with some (R*,S*)-glycols, this drawback can be removed by the use of 2,4,6-collidine instead of pyridine; 1,1â²-oxalyldiimidazole is useful for the synthesis of two selected cyclic oxalates 2e, f. The cyclic oxalates 2 other than trisubstituted and tetrasubstituted ones were found to be very reactive: kinetic studies on the hydrolysis of 1,4-dioxane-2,3-dione (2a) as well as its mono- and some selected 5,6-disubstituted derivatives 2 have revealed that they undergo hydrolysis 260-1500 times more rapidly than diethyl oxalate (12) in acetate buffer-acetonitrile (pH 5.69) at 25°C. Although the cyclic oxalate 2l from cis-1,2-cyclopentanediol (1l) was 1.5 times more reactive than 2a, it has been shown with other substrates that increasing number of the alkyl substituents decreases the rate of hydrolysis. On the contrary, the phenyl group was found to have somewhat accelerative effect. © 2002 Pharmaceutical Society of Japan