Skimmia

Slfinrnnianini , C14H13O4N. This alkaloid was first isolated from the leaves oi Skimmia japonica Thunb. by Honda, and later from S, laureola Hook by Chopra et It has also been recorded from Fagara spp. 

Some quinoline alkaloids from the aerial parts of Skimmia laureola (DC.) Dene have shown antiChE activity in vitro and methyl isoplatydesmine (49) was shown to be the most active inhibitor of both AChE and BuChE. Solanidine (50), related compounds and glycosides are... 

Dictamnine (158) was first isolated from white dittany root (Dictamnus albus L.) (23MI31700). Later, it was found in the leaves of Skimmia repens Nakai, by Asahina and coworkers (30CB2045), who proved its identity with the dictamnus-root alkaloid and elucidated its structure. Dictamnine forms colorless prisms with m.p. 132-133 °C. 

Evodia merrillii, Ruta graveolens, Skimmia arborescens, S.japonica Dictamnus, Esenbeckia, Fagara, Glycosmis, Haplophyllum,... 

Skimmia laureola Oil A North Indian shrub whose leaves are burned as incense there. The leaf oil has 4.6% vanillin [77]. 

Isolation and Detection.—The isolation of new quinoline alkaloids and of alkaloids of established structure that have been obtained from new sources is recorded in the Table.Thin-layer chromatography is employed increasingly to recognize the presence of known quinoline alkaloids, and a useful account of the application of the method to a large group of quinoline alkaloids is now available. Gas-liquid chromatography was introduced for the detection and estimation of quinoline alkaloids and was applied to the analysis of basic extracts of Skimmia species and of Otoisya ternata. A bisexual Skimmia hybrid contains skimmianine (1 = H, =... 

Hydroxy-l-methyl-2-phenyl-4-quinolone (3), obtained previously from Lunasia quercifolia, now has been isolated from Skimmia japonica. Details have been published of the Italian synthesis of halfordamine (6) (see Vol. 4 and Vol. 5 of these Reports) and related 2-quinolones. ... 

Skimmtn. 7-(0-D-Glucopyrano ytoxy -2H-I-ben-zopyran-2-ane 7-(glucosyloxy)coumarin 7 -hydroxycouma-rin -7 -glucoside umbelliferone glucoside. C,sH]403 mo] wt 324.28. C 55.55%, H 4.97%, O 39,47%. In bark and wood of Skimmia japonica Thunb., Rutaceae. lsoln, structure and synthesis Spath. Neufeld, Rec. Trav. Chim. ST, 535 (1938). 

A quaternary alkaloid extracted by Boyd and Grundon (37) from leaves of Skimmia japonica Thunb. was shown to be the (+)-A/-methyl-platydesminium salt (51) by comparison with the racemate that had been synthesized earlier (27). The alkaloid has subsequently been isolated from Ruta graveolens (39) and from Araliopsis tabouensis (66). 

Earlier theories of the biosynthesis of quinoline alkaloids found in the Rutaceae have been discussed in Volume IX of this treatise, and the first experimental results using radioactive tracers were also reviewed. Spenser and his collaborators showed that anthranilic acid is incorporated intact into dictamnine in Dictamnus albus and that C-10 and C-ll (cf. 328) are derived from C-l and C-2 of acetate, respectively (220). Matsuo et al. (221) demonstrated almost simultaneously that the quinoline ring of skimmianine in Skimmia japonica was formed similarly. Since then, the biosynthesis of furo- and isopropyldihydrofuroquinoline alkaloids has been studied intensively, with particular interest in the origin of the C2 and C5 side chains present at the 3-position of the quinoline ring of these alkaloids. 

Quinoline Alkaloids.—An efficient and specific conversion of (-f)-platydesmine (156), C-labelled as shown, into dictamnine (157) has been demonstrated in Skimmia japonica, as has its presence in this plant. Its role as an intermediate between the dimethylallylquinoline (155) and the furanoquinoline dictamnine is thus established. Platydesmine was also incorporated into platydesminium metho-salt (159) and skimmianine (158), but into the latter with low efficiency. The metho-salt (159) was poorly incorporated into dictamnine. 

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