Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation
Proanthocyanidins, also known as condensed tannins or oligomeric flavonoids, are found in many edible plants and exhibit interesting biological activities. Herein, we report a new, simple method for the stereoselective synthesis of procyanidin B6, a (+)-catechin-(4-6)-(+)-catechin dimer, by Lewis ac...
Main Authors: | , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2018-01-01
|
Series: | Molecules |
Subjects: | |
Online Access: | http://www.mdpi.com/1420-3049/23/1/205 |
id |
doaj-fed0581131cb4f058bfa907d68ba98e0 |
---|---|
record_format |
Article |
spelling |
doaj-fed0581131cb4f058bfa907d68ba98e02020-11-24T23:58:16ZengMDPI AGMolecules1420-30492018-01-0123120510.3390/molecules23010205molecules23010205Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular CondensationYusuke Higashino0Taisuke Okamoto1Kazuki Mori2Takashi Kawasaki3Masahiro Hamada4Noriyuki Nakajima5Akiko Saito6Graduate School of Engineering, Osaka Electro-Communication University (OECU), 18-8 Hatsu-cho, Neyagawa-shi, Osaka 572-8530, JapanGraduate School of Engineering, Osaka Electro-Communication University (OECU), 18-8 Hatsu-cho, Neyagawa-shi, Osaka 572-8530, JapanGraduate School of Engineering, Osaka Electro-Communication University (OECU), 18-8 Hatsu-cho, Neyagawa-shi, Osaka 572-8530, JapanCollege of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, JapanDepartment of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University (TPU), 5180, Kurokawa, Imizu, Toyama 939-0398, JapanDepartment of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University (TPU), 5180, Kurokawa, Imizu, Toyama 939-0398, JapanGraduate School of Engineering, Osaka Electro-Communication University (OECU), 18-8 Hatsu-cho, Neyagawa-shi, Osaka 572-8530, JapanProanthocyanidins, also known as condensed tannins or oligomeric flavonoids, are found in many edible plants and exhibit interesting biological activities. Herein, we report a new, simple method for the stereoselective synthesis of procyanidin B6, a (+)-catechin-(4-6)-(+)-catechin dimer, by Lewis acid-catalyzed intramolecular condensation. The 5-O-t-butyldimethylsilyl (TBDMS) group of 5,7,3′4′-tetra-O-TBDMS-(+)-catechin was regioselectively removed using trifluoroacetic acid, leading to the “regio-controlled” synthesis of procyanidin B6. The 5-hydroxyl group of the 7,3′,4′-tri-O-TBDMS-(+)-catechin nucleophile and the 3-hydroxyl group of 5,7,3′,4′-tetra-O-benzylated-(+)-catechin electrophile were connected with an azelaic acid. The subsequent SnCl4-catalyzed intramolecular condensation proceeded smoothly to give the 4-6-condensed catechin dimer. This is the first report on the complete regioselective synthesis of a 4-6-connected oligomer without modifying the 8-position.http://www.mdpi.com/1420-3049/23/1/205condensed tanninproanthocyanidinsintramolecular condensationprocyanidin B6 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yusuke Higashino Taisuke Okamoto Kazuki Mori Takashi Kawasaki Masahiro Hamada Noriyuki Nakajima Akiko Saito |
spellingShingle |
Yusuke Higashino Taisuke Okamoto Kazuki Mori Takashi Kawasaki Masahiro Hamada Noriyuki Nakajima Akiko Saito Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation Molecules condensed tannin proanthocyanidins intramolecular condensation procyanidin B6 |
author_facet |
Yusuke Higashino Taisuke Okamoto Kazuki Mori Takashi Kawasaki Masahiro Hamada Noriyuki Nakajima Akiko Saito |
author_sort |
Yusuke Higashino |
title |
Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation |
title_short |
Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation |
title_full |
Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation |
title_fullStr |
Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation |
title_full_unstemmed |
Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+)-Catechin Dimer, by Intramolecular Condensation |
title_sort |
regioselective synthesis of procyanidin b6, a 4-6-condensed (+)-catechin dimer, by intramolecular condensation |
publisher |
MDPI AG |
series |
Molecules |
issn |
1420-3049 |
publishDate |
2018-01-01 |
description |
Proanthocyanidins, also known as condensed tannins or oligomeric flavonoids, are found in many edible plants and exhibit interesting biological activities. Herein, we report a new, simple method for the stereoselective synthesis of procyanidin B6, a (+)-catechin-(4-6)-(+)-catechin dimer, by Lewis acid-catalyzed intramolecular condensation. The 5-O-t-butyldimethylsilyl (TBDMS) group of 5,7,3′4′-tetra-O-TBDMS-(+)-catechin was regioselectively removed using trifluoroacetic acid, leading to the “regio-controlled” synthesis of procyanidin B6. The 5-hydroxyl group of the 7,3′,4′-tri-O-TBDMS-(+)-catechin nucleophile and the 3-hydroxyl group of 5,7,3′,4′-tetra-O-benzylated-(+)-catechin electrophile were connected with an azelaic acid. The subsequent SnCl4-catalyzed intramolecular condensation proceeded smoothly to give the 4-6-condensed catechin dimer. This is the first report on the complete regioselective synthesis of a 4-6-connected oligomer without modifying the 8-position. |
topic |
condensed tannin proanthocyanidins intramolecular condensation procyanidin B6 |
url |
http://www.mdpi.com/1420-3049/23/1/205 |
work_keys_str_mv |
AT yusukehigashino regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation AT taisukeokamoto regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation AT kazukimori regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation AT takashikawasaki regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation AT masahirohamada regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation AT noriyukinakajima regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation AT akikosaito regioselectivesynthesisofprocyanidinb6a46condensedcatechindimerbyintramolecularcondensation |
_version_ |
1725450856257552384 |