Phenolic Compounds from the Aerial Parts of <i>Diplomorpha canescens</i>

6,8-Di-C-methyl-flavonoids with neuroprotective activities from Rhododendron fortunei

“…Repeated chromatographic purification of the EtOAc and n-BuOH fractions by silica gel, RP C-18, Sephadex LH-20, and HPLC resulted in the isolation of ten C-methyl-flavonoids, of which six are new compounds. Comparing their NMR data with reported values, we assigned the sructures of the four known C-methyl-flavonoids to be farrerol (4b) 22 , (2R,3R)-6,8-di-C-methyldi-hydrokaempferol (7) 21 , 6,8-di-C-met-hylkaempferol 7-O-β-D-glucopyranoside (8) 23 , and 6,8-di-C-methyl-kaempferol (9) 18 . Compound 1 was obtained as a yellow amorphous solid.…”

“…Their CD spectra ( Figure 4) are totally different, and are almost mirror images of each other. The absolute configuration of C-2 in compound 4a was determined as R by a positive Cotton effect at 290 nm and a negative Cotton effect at 334 nm in the CD spectrum 22,28 , while the 2S configuration in compound 4b was determined by the negative Cotton effect at 290 nm and the positive Cotton effect at 335 nm in the CD spectrum. Thus, compound 4a was established as (2R)-farrerol.…”

Thotneosides A, B and C: Potent Antioxidants from Nepalese Crude Drug, Leaves of <i>Aconogonon molle</i>

“…The absolute configuration of D-glucopyranosyl moiety in compound 2 was further supported by the application of Klyne's rule, 7) as the sign for the molecular rotation ([MD] D ) of 2 (−122.8°) is similar to the sign of methyl-β-Dglucopyranoside (−66.3°). 10,11) Thus, the structure of compound 2 was elucidated as quercetin- +44.3° and co-TLC with authentic sample. The absolute configuration of D-glucopyranosyl moiety in compound 3 was further confirmed by the application of Klyne's rule, 7) as the sign of molecular rotation of compound 3 (−84.3°) was similar to the molecular rotation…”

Diplomorphanins A and B: New <i>C</i>-Methyl Flavonoids from <i>Diplomorpha canescens</i>

“…2) We have previously reported four new compounds such as (2R,3S)-6,8-di-C-methyldihydrokaempferol, (2R,3R)-6,8-di-C-methyldihydrokaempferol, 3) farrerol 4′-O-β-d-glucopyranoside (4), 4) and diplomorphanone A 5) along with twenty-five known compounds from the aerial parts of D. canescens. In continuing further chemical analysis, we isolated and identified two new C-methyl flavonoids, diplomorphanins A (1) and B (2) along with farrerol 7-O-β-dglucopyranoside (3) 6) ( Fig.…”

“…Acid Hydrolysis of 1 Acid hydrolysis was performed by heating a solution of compound 1 (8.0 mg) in 2 M HCl (2 mL) in a sealed tube at 70°C for 3 h. The aglycone (5, 4.0 mg) was extracted with EtOAc and the structure was confirmed as farrerol 4) by comparing its NMR data and co-TLC with an authentic sample. …”