The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Michio Takido - One of the best experts on this subject based on the ideXlab platform.
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constituents of compositae plants 2 triterpene diols Triols and their 3 o fatty acid esters from edible chrysanthemum flower extract and their anti inflammatory effects
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Motohiko Ukiya, Yoshimasa Kasahara, Yumiko Kimura, Tamotsu Nikaido, Kazuo Koike, Toshihiro Akihisa, Ken Yasukawa, Michio TakidoAbstract:The n-hexane soluble and the nonsaponifiable lipid fractions of the edible flower extract of chrysanthemum (Chrysanthemum morifolium) were investigated for triterpene diol and triol constituents. These triterpenes occur as the 3-O-fatty acid esters in the n-hexane soluble fraction from which 26 new and 6 known fatty acid esters were isolated and characterized. From the nonsaponifiable lipid fraction, 24 triterpene diols and Triols were isolated, of which 3 were new compounds: (24S)-25-methoxycycloartane-3β,24-diol (11), (24S)-25-methoxycycloartane-3β,24,28-triol (22), and 22α-methoxyfaradiol (23). Faradiol (9) and heliantriol C (19), present in the nonsaponifiable lipid fraction and as the 3-O-palmitoyl esters in the n-hexane soluble fraction, were the most predominant triterpene diol and triol constituents. Fourteen triterpene diols and Triols and 9 fatty acid esters were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in...
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constituents of compositae plants 2 triterpene diols Triols and their 3 o fatty acid esters from edible chrysanthemum flower extract and their anti inflammatory effects
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Motohiko Ukiya, Yoshimasa Kasahara, Yumiko Kimura, Tamotsu Nikaido, Kazuo Koike, Toshihiro Akihisa, Ken Yasukawa, Michio TakidoAbstract:The n-hexane soluble and the nonsaponifiable lipid fractions of the edible flower extract of chrysanthemum (Chrysanthemum morifolium) were investigated for triterpene diol and triol constituents. These triterpenes occur as the 3-O-fatty acid esters in the n-hexane soluble fraction from which 26 new and 6 known fatty acid esters were isolated and characterized. From the nonsaponifiable lipid fraction, 24 triterpene diols and Triols were isolated, of which 3 were new compounds: (24S)-25-methoxycycloartane-3beta,24-diol (11), (24S)-25-methoxycycloartane-3beta,24,28-triol (22), and 22alpha-methoxyfaradiol (23). Faradiol (9) and heliantriol C (19), present in the nonsaponifiable lipid fraction and as the 3-O-palmitoyl esters in the n-hexane soluble fraction, were the most predominant triterpene diol and triol constituents. Fourteen triterpene diols and Triols and 9 fatty acid esters were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in mice. All of the triterpenes examined showed marked inhibitory activity, with a 50% inhibitory dose (ID50) of 0.03-1.0 mg/ear, which was more inhibitive than quercetin (ID50 = 1.6 mg/ear), a known inhibitor of TPA-induced inflammation in mice.
Comfort M. Nkambule - One of the best experts on this subject based on the ideXlab platform.
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dibutyltin oxide mediated diastereoselective cyclodehydration sulfonylation of 1 2 4 Triols
Tetrahedron Letters, 2015Co-Authors: Makhosazana P. Gamedze, Comfort M. NkambuleAbstract:Abstract Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-Triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-Triols favouring cyclodehydration (78–85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-Triols favouring monosulfonylation (66–87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-Triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72–79% yields.
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Dibutyltin oxide mediated diastereoselective cyclodehydration/sulfonylation of 1,2,4-Triols
Tetrahedron Letters, 2015Co-Authors: Makhosazana P. Gamedze, Comfort M. NkambuleAbstract:Abstract Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-Triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-Triols favouring cyclodehydration (78–85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-Triols favouring monosulfonylation (66–87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-Triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72–79% yields.
Cornelia Herriger - One of the best experts on this subject based on the ideXlab platform.
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asymmetric synthesis of 2 trifluoromethyl 1 2 3 Triols
European Journal of Organic Chemistry, 2007Co-Authors: Dieter Enders, Cornelia HerrigerAbstract:The asymmetric synthesis of the 2-trifluoromethylated 1,2,3-Triols 5 starting from 2,2-dimethyl-1,3-dioxan-5-one (1) is described. The enantiomerically pure α-alkylated dioxanones 3 and 6 were obtained via the SAMP/RAMP hydrazone methodology. Trifluoromethylation of the monoalkylated dioxanones 3 with (trifluoromethyl)trimethylsilane in the presence of TBAF gave the 2-trifluoromethylated acetonide-protected Triols 4 in high diastereo-and enantiomeric excesses (de ≥ 96 %, ee = 92 – ≥ 98 %) and good overall yields (52–97 %). Finally, deprotection of the triol under acidic conditions afforded the title compound 5 (de ≥ 96 %, ee = 95, 96 %) as a typical example. In addition, the methodology was extended to the trialkylated dioxanone 6 leading to the trifluoromethylated alcohol 7 with two neighbouring quaternarystereocenters in good yield (77 %) and very good diastereo- and enantiomeric excesses (de ≥ 96 %, ee = 98 %). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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Asymmetric Synthesis of 2‐Trifluoromethyl‐1,2,3‐Triols
European Journal of Organic Chemistry, 2007Co-Authors: Dieter Enders, Cornelia HerrigerAbstract:The asymmetric synthesis of the 2-trifluoromethylated 1,2,3-Triols 5 starting from 2,2-dimethyl-1,3-dioxan-5-one (1) is described. The enantiomerically pure α-alkylated dioxanones 3 and 6 were obtained via the SAMP/RAMP hydrazone methodology. Trifluoromethylation of the monoalkylated dioxanones 3 with (trifluoromethyl)trimethylsilane in the presence of TBAF gave the 2-trifluoromethylated acetonide-protected Triols 4 in high diastereo-and enantiomeric excesses (de ≥ 96 %, ee = 92 – ≥ 98 %) and good overall yields (52–97 %). Finally, deprotection of the triol under acidic conditions afforded the title compound 5 (de ≥ 96 %, ee = 95, 96 %) as a typical example. In addition, the methodology was extended to the trialkylated dioxanone 6 leading to the trifluoromethylated alcohol 7 with two neighbouring quaternarystereocenters in good yield (77 %) and very good diastereo- and enantiomeric excesses (de ≥ 96 %, ee = 98 %). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Motohiko Ukiya - One of the best experts on this subject based on the ideXlab platform.
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constituents of compositae plants 2 triterpene diols Triols and their 3 o fatty acid esters from edible chrysanthemum flower extract and their anti inflammatory effects
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Motohiko Ukiya, Yoshimasa Kasahara, Yumiko Kimura, Tamotsu Nikaido, Kazuo Koike, Toshihiro Akihisa, Ken Yasukawa, Michio TakidoAbstract:The n-hexane soluble and the nonsaponifiable lipid fractions of the edible flower extract of chrysanthemum (Chrysanthemum morifolium) were investigated for triterpene diol and triol constituents. These triterpenes occur as the 3-O-fatty acid esters in the n-hexane soluble fraction from which 26 new and 6 known fatty acid esters were isolated and characterized. From the nonsaponifiable lipid fraction, 24 triterpene diols and Triols were isolated, of which 3 were new compounds: (24S)-25-methoxycycloartane-3β,24-diol (11), (24S)-25-methoxycycloartane-3β,24,28-triol (22), and 22α-methoxyfaradiol (23). Faradiol (9) and heliantriol C (19), present in the nonsaponifiable lipid fraction and as the 3-O-palmitoyl esters in the n-hexane soluble fraction, were the most predominant triterpene diol and triol constituents. Fourteen triterpene diols and Triols and 9 fatty acid esters were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in...
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constituents of compositae plants 2 triterpene diols Triols and their 3 o fatty acid esters from edible chrysanthemum flower extract and their anti inflammatory effects
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Motohiko Ukiya, Yoshimasa Kasahara, Yumiko Kimura, Tamotsu Nikaido, Kazuo Koike, Toshihiro Akihisa, Ken Yasukawa, Michio TakidoAbstract:The n-hexane soluble and the nonsaponifiable lipid fractions of the edible flower extract of chrysanthemum (Chrysanthemum morifolium) were investigated for triterpene diol and triol constituents. These triterpenes occur as the 3-O-fatty acid esters in the n-hexane soluble fraction from which 26 new and 6 known fatty acid esters were isolated and characterized. From the nonsaponifiable lipid fraction, 24 triterpene diols and Triols were isolated, of which 3 were new compounds: (24S)-25-methoxycycloartane-3beta,24-diol (11), (24S)-25-methoxycycloartane-3beta,24,28-triol (22), and 22alpha-methoxyfaradiol (23). Faradiol (9) and heliantriol C (19), present in the nonsaponifiable lipid fraction and as the 3-O-palmitoyl esters in the n-hexane soluble fraction, were the most predominant triterpene diol and triol constituents. Fourteen triterpene diols and Triols and 9 fatty acid esters were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in mice. All of the triterpenes examined showed marked inhibitory activity, with a 50% inhibitory dose (ID50) of 0.03-1.0 mg/ear, which was more inhibitive than quercetin (ID50 = 1.6 mg/ear), a known inhibitor of TPA-induced inflammation in mice.
Makhosazana P. Gamedze - One of the best experts on this subject based on the ideXlab platform.
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dibutyltin oxide mediated diastereoselective cyclodehydration sulfonylation of 1 2 4 Triols
Tetrahedron Letters, 2015Co-Authors: Makhosazana P. Gamedze, Comfort M. NkambuleAbstract:Abstract Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-Triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-Triols favouring cyclodehydration (78–85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-Triols favouring monosulfonylation (66–87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-Triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72–79% yields.
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Dibutyltin oxide mediated diastereoselective cyclodehydration/sulfonylation of 1,2,4-Triols
Tetrahedron Letters, 2015Co-Authors: Makhosazana P. Gamedze, Comfort M. NkambuleAbstract:Abstract Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-Triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-Triols favouring cyclodehydration (78–85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-Triols favouring monosulfonylation (66–87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-Triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72–79% yields.
