31087-58-8Relevant academic research and scientific papers
(±)-Diinsininone: made nature's way
Selenski, Carolyn,Pettus, Thomas R.R.
, p. 5298 - 5307 (2007/10/03)
We report the synthesis of diinsininone (33), the aglycone of (±)-diinsinin (2). Thereby, we complete the first construction of a proanthocyanidin (PA) type-A compound incorporating a [3.3.1]-bicyclic ketal as its characteristic core. Our strategy utilizes a coupling between a benzopyrilium salt and a flavanone that proves applicable to other PA type-A compounds. During this undertaking, treatment of naringenin (9) with 2-iodoxybenzoic acid (IBX) followed by reductive work-up affords eriodictyol (10). This reactivity mirrors that of catechol hydroxylase (F3H) found in the flavonoid pathway. Other interesting transformations include the formation of flavonoids through an ortho-quinone methide (o-QM) cycloaddition-oxidation sequence and regioselective β-glycosidations of several unprotected flavanones suggesting a likely synthesis of 2 from the aglycone 33.
Total synthesis of apigenin 7,4′-di-O-β-glucopyranoside, a component of blue flower pigment of Salvia patens, and seven chiral analogues
Oyama, Kin-Ichi,Kondo, Tadao
, p. 2025 - 2034 (2007/10/03)
We have succeeded in the first total synthesis of apigenin 7,4′-di-O-β-D-glucopyranoside (1a), a component of blue pigment, protodelphin, from naringenin (2). Glycosylation of 2 according to Koenigs-Knorr reaction provided a monoglucoside 4a in 80% yield, and this was followed by DDQ oxidation to give apigenin 7-O-glucoside (12a). Further glycosylation of 4′-OH of 12a with 2,3,4,6-tetra-O-acetyl-α-D- glucopyranosyl fluoride (5a) was achieved using a Lewis acid-and-base promotion system (BF3·Et2O, 2,6-di-tert-butyl-4- methylpyridine, and 1,1,3,3-tetramethylguanidine) in 70% yield, and subsequent deprotection produced 1a. Synthesis of three other chiral isomers of 1a, with replacement of D-glucose at 7 and/or 4′-OH by L-glucose (1b-d), and four chiral isomers of apigenin 7-O-β-glucosides (6a,b) and 4′-O-β- glucosides (7a,b) also proved possible.
Chiral molecular recognition on formation of a metalloanthocyanin: A supramolecular metal complex pigment from blue flowers of salvia patens
Kondo, Tadao,Oyama, Kin-Ichi,Yoshida, Kumi
, p. 894 - 897 (2007/10/03)
Most blue flower color is the result of a metalloanthocyanin, a stoichiometric self-assembled supramolecular pigment consisting of six molecules of an anthocyanin, six molecules of an anthocyanin, six molecules of flavone, and two metal atoms. We have iso
