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Three new cucwbitacins as well as thirteen know ones were isolated from the h i t s of B v n i a vemcosa. The new compounds were characterized by chemical and qxxtral methods.An effective and simple method to isomerize 2-hydroxy-3-ketocucurbiracins in acid media is described.

Letters a group of PAHs are present in the plant extract and contributed to the light-mediated antiviral activity. We believe that the source of the PAHs was not from contamination in the purification procedure. With separation and analytical techniques capable of purifying trace components, it is more of a possibility that impurities from materials used in the processing can be accumj.ilated and be found in an identifiable quantity. The major solvent used in this procedure consisted of a mixture of hexanes. The impurities remaining from the evaporation of four liters of hexanes under reduced pressure were submitted for NMR and the spectrum obtained was not complex enough to indicate the presence of PAHs. Polycycic aromatic hydrocarbons have been found in foliage as well as in crops (6). PAils are generated by the incomplete combustion of fossil fuels and are found throughout the environment. If the occurrence of 245-261.

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