N-methylpseudoephedrine, diacetone-D-glucose, thiol 계통의 카이랄 보조기를 이용하여 carboxyalkylated flavones 을 비대칭 합성하였다. 동적 열역학적 분할을 통해 N-methylpseudoephedrine 을 카이랄 보조기로 이용하여 O-carboxyalkylated flavones 을 합성할 수 있었다. 용매로 MeCN, base 로 Cs2CO3을 이용한 6-hydroxy flavone 의 치환반응을 통해 98:2 er 값을 갖는 O-carboxyalkylated flavones 을 합성하였고, ...
N-methylpseudoephedrine, diacetone-D-glucose, thiol 계통의 카이랄 보조기를 이용하여 carboxyalkylated flavones 을 비대칭 합성하였다. 동적 열역학적 분할을 통해 N-methylpseudoephedrine 을 카이랄 보조기로 이용하여 O-carboxyalkylated flavones 을 합성할 수 있었다. 용매로 MeCN, base 로 Cs2CO3을 이용한 6-hydroxy flavone 의 치환반응을 통해 98:2 er 값을 갖는 O-carboxyalkylated flavones 을 합성하였고, 친핵체로 chrysin을 이용한 경우에도 96:4 er 이상의 높은 입체 선택성을 보이는 7-O-carboxyalkylated chrysins 을 얻었다. 카이랄 보조기로 diacetone-D-glucose 을 이용하여 O-, N-carboxyalkylated flavones 을 합성할 수 있었다. DIEA, TBAI 존재 하, amino flavones 과 α-bromo acetate 의 반응을 통해 99:1 dr 의 높은 입체선택성을 갖는 N-carboxyalkylated flavones 을 얻었다. 반면 K2CO3 를 base 로 이용한 hydroxyl flavones 과 α-bromo acetate 의 반응은 다소 낮은 입체선택성을 보였다. 마지막으로 thiol 카이랄 보조기는 광학적으로 순수한 α-mercapto carboxylic acid 유도체로부터 합성이 가능하다. 이렇게 합성한 α-bromo thio ester를 DIEA, TBAI 존재 하에 amino flavones 과 반응시켜 80:20 er 값을 갖는 N-carboxyalkylated flavones 을 합성하였다.
N-methylpseudoephedrine, diacetone-D-glucose, thiol 계통의 카이랄 보조기를 이용하여 carboxyalkylated flavones 을 비대칭 합성하였다. 동적 열역학적 분할을 통해 N-methylpseudoephedrine 을 카이랄 보조기로 이용하여 O-carboxyalkylated flavones 을 합성할 수 있었다. 용매로 MeCN, base 로 Cs2CO3을 이용한 6-hydroxy flavone 의 치환반응을 통해 98:2 er 값을 갖는 O-carboxyalkylated flavones 을 합성하였고, 친핵체로 chrysin을 이용한 경우에도 96:4 er 이상의 높은 입체 선택성을 보이는 7-O-carboxyalkylated chrysins 을 얻었다. 카이랄 보조기로 diacetone-D-glucose 을 이용하여 O-, N-carboxyalkylated flavones 을 합성할 수 있었다. DIEA, TBAI 존재 하, amino flavones 과 α-bromo acetate 의 반응을 통해 99:1 dr 의 높은 입체선택성을 갖는 N-carboxyalkylated flavones 을 얻었다. 반면 K2CO3 를 base 로 이용한 hydroxyl flavones 과 α-bromo acetate 의 반응은 다소 낮은 입체선택성을 보였다. 마지막으로 thiol 카이랄 보조기는 광학적으로 순수한 α-mercapto carboxylic acid 유도체로부터 합성이 가능하다. 이렇게 합성한 α-bromo thio ester를 DIEA, TBAI 존재 하에 amino flavones 과 반응시켜 80:20 er 값을 갖는 N-carboxyalkylated flavones 을 합성하였다.
The asymmetric syntheses of carboxyalkylated flavones using N-methylpseudoephedrine, diacetone-D-glucose and a thiol as a chiral auxiliary have been investigated. We synthesized O-carboxyalkylated flavones stereosectively via dynamic thermodynamic resolution of N-methylpseudoephedrine as a chiral au...
The asymmetric syntheses of carboxyalkylated flavones using N-methylpseudoephedrine, diacetone-D-glucose and a thiol as a chiral auxiliary have been investigated. We synthesized O-carboxyalkylated flavones stereosectively via dynamic thermodynamic resolution of N-methylpseudoephedrine as a chiral auxiliary. Substitution with 6-hydroxy flavone, Cs2CO3 in MeCN provided O-carboxyalkylated flavone with 98:2 er. In substitution with chrysin as a nucleophile, several 7-O-carboxyalkylated chrysins were provided with high stereoselectivities higher than 96:4 er. Also, we have developed the syntheses of O-, N-carboxyalkylated flavones via diacetone-D-glucose as a chiral auxiliary. In the presence of DIEA and TBAI, amino flavones react with α-bromo acetate to provide N-carboxyalkylated flavones were provided with high stereoselectivity up to 99:1 dr. In the presence of K2CO3, the reaction of hydroxyl flavones with α-bromo acetate provided O-carboxyalkylated flavones with low stereoselectivities. In addition, thiol chiral auxiliary is prepared from optically pure α-mercapto carboxylic acid derivative. In the presence of TBAI and DIEA, α-bromo thio ester reacts with 60amino flavone to provide N-carboxyalkylated flavone with 80:20 er.
The asymmetric syntheses of carboxyalkylated flavones using N-methylpseudoephedrine, diacetone-D-glucose and a thiol as a chiral auxiliary have been investigated. We synthesized O-carboxyalkylated flavones stereosectively via dynamic thermodynamic resolution of N-methylpseudoephedrine as a chiral auxiliary. Substitution with 6-hydroxy flavone, Cs2CO3 in MeCN provided O-carboxyalkylated flavone with 98:2 er. In substitution with chrysin as a nucleophile, several 7-O-carboxyalkylated chrysins were provided with high stereoselectivities higher than 96:4 er. Also, we have developed the syntheses of O-, N-carboxyalkylated flavones via diacetone-D-glucose as a chiral auxiliary. In the presence of DIEA and TBAI, amino flavones react with α-bromo acetate to provide N-carboxyalkylated flavones were provided with high stereoselectivity up to 99:1 dr. In the presence of K2CO3, the reaction of hydroxyl flavones with α-bromo acetate provided O-carboxyalkylated flavones with low stereoselectivities. In addition, thiol chiral auxiliary is prepared from optically pure α-mercapto carboxylic acid derivative. In the presence of TBAI and DIEA, α-bromo thio ester reacts with 60amino flavone to provide N-carboxyalkylated flavone with 80:20 er.
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