Chemistry of the compositae. Part 38. Structure and absolute configuration of gallicin, a new germacranolide from Artemisia

Abstract

Gallicin, a new germacranolide, w a s isolated from Arternisia rnaritirna gallica Willd and assigned structure (3a) on chemical and spectroscopic evidence. Its absolute configuration w a s determined by the fact that it can be converted to the dihydrosantamarin (5) by a biogenetic cyclization process.ARTEMIN (1) was earlier isolated from Artemisia maritima and now from the same species two more sesquiterpene lactones have been separated. One has been identified by its physical constants and spectral data as 1 p-hydroxy-6B,7cc, 11 pH-selin-4-en-6,12-olide (2) previously obtained in this laboratory.2 The second lactone not hitherto reported has been called gallicin (3a).Gallicin, C15H2203, m/e 232 ( M -IS), displays hydroxy group, y-lactone, and C-C double bond i.r. absorptions; its l H n.m.r. spectrum shows a doublet at 6 1.20 ( J 7 Hz) due to a secondary methyl (ll-Me)J a doublet at 6 1.70 ( J 2 Hz) assigned to a vinyl methyl (4-Me), a complex signal a t 6 3.90 (l-H)J a doublet of doublets ( J 10 and 9 Hz) at 6 4.40 (6-H), two broad singlets at 6 4.75 and 5.17 (15-H), and a doublet ( J 9 Hz) a t 6 5.15 (5-H).Judging from the nature and number of its functional groups and its composition in general, gallicin would seem to have a bicyclic skeleton, which, taken together with its lH n.m.r. spectrum, indicates the germacranot Part 37, A

Novel Flavoalkaloids from White Tea with Inhibitory Activity against the Formation of Advanced Glycation End Products

“…The n-butanol-soluble fraction was fractionated by repeated CC and semi-preparative HPLC to provide four flavoalkaloids (Figure 2): two novel pure compounds (1 and 2) and a mixture of two isomers (3a and 3b). At the same time, 12 known compounds were obtained from the Chinese commercial white tea, including gallicin (4), 24 (+)-catechin (5), 25 (−)-epicatechin (6), 25 gallic acid (7), 26 kaempferol (8), 27 procyanidin B2 (9), 28 kaempferol-3− 7-O-β-D-dirhamnoside (10), 29 epigallocatechin-(4β-8)-epicatechin-3-O-gallate (11), 30 EGCG (12), 31 1,6-di-O-galloyl-β-Dglucose ( 13), 32 1-O-galloyl-4,6-(−)-hexahydroxydiphenoyl-β-Dglucose ( 14), 30 and 1,4,6-tri-O-galloyl-β-D-glucose (15). 30 Compounds 1, 2, 3a, and 3b showed a similar IR spectrum, which suggested the presence of hydroxyl groups (broad peak around 3397 cm −1 ), carbonyl groups (1695 cm −1 ), and aromatic rings (1620 and 1539 cm −1 ).…”

Flavones and Sesquiterpene Lactones from Achillea atrata subsp. multifida: Antimicrobial Activity

“…Si gel column chromatography of the crude extract, followed by rechromatography of selected fractions exhibiting antimicrobial activity and/or containing compounds that could be interesting from a pharmacological as well as a phytochemical point of view (e.g., sesquiterpene lactones), afforded the four flavones, santin ( 1 ), centaureidin ( 2 ), apigenin ( 3 ), and its 7- O -β-glucoside ( 4 ) . In addition, nine sesquiterpene lactones, all belonging to a 12,6α-olide group (with 11αH configuration), have been isolated: 8α-hydroxy-1α,4α,5α,11βH-guaia-10(14)-en-12,6α-olide ( 5 , a new guaianolide), the elemanolide temisin ( 6 ), three germacranolides [balchanolide ( 7 ), 1β-hydroperoxy-8α-hydroxygermacra-4,10(14)-dien-6β,7α,11βH-12,6α-olide ( 8 ), shonachalin A ( 9 ) 13 ], and four eudesmanolides [11β,13-dihydroreynosin ( 10 ), 1β-hydroxy-6β,7α,11βH-selin-3-en-6,12-olide ( 11 ), 8α-hydroxy-11β,13-dihydrobalchanin ( 12 ), and artapshin ( 13 ) 15 ]. The lactones and flavones isolated previously from other plants were identified by comparison of their spectral data with the published ones.…”

Sesquiterpenes and Other Constituents from Dendranthema zawadskii var. latilobum

“…The chemical shifts and the values of the coupling constants of H-13 at δ H 1.14 (d, J=7.4 Hz) and H-11 at δ H 2.75 (dq, J=7.9, 7.8 Hz), as well as the chemical shift of C-13 at δ C 9.8, suggested that both H-7 and H-11 were in the cis-configuration relative to each other. 18,20,27) All these results established that 4 was 1β,3β,15-trihydroxy-germacra-4Z,10(14)-dien-6β,7α,11αH-12,6-olide and named zawadskinolide D.…”