Phenanthrenes, 9,10-dihydrophenanthrenes, bibenzyls with their derivatives, and malate or tartrate benzyl ester glucosides from tubers of Cremastra appendiculata

Chemical Constituents from the Aerial Parts of Cyrtopodium paniculatum

“…The methylene at position C-13 also had NOESY correlation with the proton H-10 on the dihydrophenanthrene subunit. The relative configuration between H-11 and H-12 was assumed to be trans because of the NOESY correlation between H-12 to H-2 /H-6 as well as the coupling constant of 3.3 Hz supporting a trans-configuration as previously reported in dihydrophenanthrenofuran derivatives [54]. The CD spectrum of 8 showed a negative Cotton effect at 273 nm, allowing the assignment of a 11S, 12R.…”

“…The connection between the two units allows a new cyclization leading to a furan ring. It is noteworthy that this kind of dihydrophenanthrene derivative is considered as a chemotaxonomic marker for the species in the genus Pleione [59,73,[75][76][77], but has been also found in the genus Bulbophyllum [55] and Cremastra [54]. The last set of compounds were the dimers, occurring as either homo-(two units of 9,10-dihydrophenanthrene or phenanthrene) or as heterodimers (combinations of a 9,10-dihydrophenanthrene and a phenanthrene unit) having a C-C bond linkage.…”

“…The last set of compounds were the dimers, occurring as either homo-(two units of 9,10-dihydrophenanthrene or phenanthrene) or as heterodimers (combinations of a 9,10-dihydrophenanthrene and a phenanthrene unit) having a C-C bond linkage. These biphenanthrene derivatives occur mostly in species of the genus Bletilla [33,41,71,[78][79][80], Bulbophyllum [55,[81][82][83] and Cremastra [54,[84][85][86][87][88]. The existence of dimers together their respective monomers in the same species provides support for a proposed biogenetic pathway for biaryl-derived compounds occurring from their corresponding monomers as a result of free radical [56] or an enzymatic oxidative phenolic coupling reaction [82,[89][90][91].…”

“…The IR spectrum showed typical absorption bands of a hydroxyl group at 3245 cm −1 and of aromatic rings at 1608, 1585, 948, 865 and 830 cm −1 . In 1D-NMR spectrum (Table 2), the presence of two deshielded aromatic proton signals at δ H 9.42 (1H, d, J = 9.2 Hz, H-5) and δ H 8.28 (1H, s, H-4 ) suggested that 4 was a dimeric molecule formed from the fusion of a phenanthrene unit [23,46,53] and a 9,10-dihydrophenanthrene subunit [28,54]. The 1 H spectrum showed resonances for a pair of ortho-coupled aromatic protons at δ H 9.42 (1H, d, J = 9.2 Hz, H-5) and 7.31 (1H, d, J = 9.2 Hz, H-6), a broad singlet integrated for two aromatic protons at δ H 7.43 (2H, s, H-9, H-10), two meta-coupled aromatic protons at δ H 6.39 (1H, d, J = 2.6 Hz, H-6 ) and 6.42 (d, J = 2.6 Hz, H-8 ) and three isolated aromatic protons at δ H 7.11 (1H, s, H-1), 6.92 (1H, s, H-1 ) and 8.28 (1H, s, H-4 ).…”

Bioactive secondary metabolites from Juncaceae species

“…Almost all of the naturally occurring phenanthrenes are substituted with hydroxy group or they can be O-glycosides, which suggests that those compounds were also hydroxylated biogenetically. 67 The hydroxy group is generally linked at C-2 or C-7. The second most common substituent is the methoxy group, mainly at positions C-2, C-4, C-5 and C-6.…”