86631-38-1Relevant articles and documents
METHOD FOR PRODUCING 4- TO 6-MER OF CATECHIN AND EPICATECHIN
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Paragraph 0059; 0060; 0063; 0064, (2016/10/08)
PROBLEM TO BE SOLVED: To provide a method for producing a 4- to 6-mer of catechin or epicatechin optical selectively and efficiently. SOLUTION: The 4- to 6-mer of catechin can be produced efficiently by using a 3- to 5-mer of catechin as a nucleophile, and a catechin monomer as an electrophile, and by reacting them in the presence of silver triflate (Ag(CF3SO3)). Furthermore, the 4- to 6-mer of epicatechin can be produced efficiently by using a 2-mer of epicatechin as a nucleophile, and a 2- to 4-mer of epicatechin monomer as an electrophile, and reacting them in the presence of zinc triflate (Zn(CF3SO3)2). SELECTED DRAWING: None COPYRIGHT: (C)2016,JPO&INPIT
Versatile synthesis of epicatechin series procyanidin oligomers, and their antioxidant and DNA polymerase inhibitory activity
Saito, Akiko,Mizushina, Yoshiyuki,Tanaka, Akira,Nakajima, Noriyuki
experimental part, p. 7422 - 7428 (2009/12/24)
Proanthocyanidins, known as condensed tannins or oligomeric flavonoids, exist in many edible plants and show various interesting biological activities. We have developed a simple and versatile method of synthesizing procyanidin oligomers consisting of (-)
Studies in polyphenol chemistry and bioactivity. 4. Synthesis of trimeric, tetrameric, pentameric, and higher oligomeric epicatechin-derived procyanidins having all-4β,8-interflavan connectivity and their inhibition of cancer cell growth through cell cycle arrest
Kozikowski, Alan P.,Tueckmantel, Werner,Boettcher, Gesine,Romanczyk Jr., Leo J.
, p. 1641 - 1658 (2007/10/03)
We report an improved synthesis of bis(5,7,3′,4′-tetra-O-benzyl)epicatechin 4β,8-dimer (3) from 5,7,3′,4′-tetra-O-benzylepicatechin (1) and 5,7,3′,4′-tetra-O-benzyl-4-(2-hydroxyethoxy)epicatechin (2) by replacing the previously employed Lewis acid, titanium tetrachloride, with the clay mineral Bentonite K-10. Under the same conditions, the benzyl-protected all-4β,8-trimer, -tetramer, and -pentamer were obtained regioselectively from their lower homologues, albeit in rapidly decreasing yields. Reaction of 2 with an organoaluminum thiolate generated from 2-mercaptobenzothiazole and trimethylaluminum followed by acetylation produced 3-O-acetyl -4-[(2-benzothiazolyl)thio]5,7,3′,4′-tetra-O-benzylepicatechin (12). Medium-sized protected oligomers with 4β,8-interflavan linkages are obtained in improved yields by using this compound as the electrophile and silver tetrafluoroborate as activator and are isolated by reversed-phase HPLC. Their deprotection by ester saponification followed by hydrogenolysis yielded the free procyanidins, which were characterized as their peracetates. The synthetic procyanidins are identical by normal-phase HPLC with fractions isolated from cocoa. The principle of chain extension by two members was demonstrated using a dimeric electrophile obtained by self-condensation of compound 12. Both the synthetic and natural pentamer 32 inhibit the growth of several breast cancer cell lines. Using the MDA MB 231 line, it was established that this outcome is based on the induction of cell cycle arrest in the G0/G1 phase. Subsequent cell death is more likely necrotic rather than apoptotic. Control experiments demonstrate that the polyphenol itself, rather than hydrogen peroxide potentially formed by its autoxidation, is the causative agent.
