Endopolygalacturonase (EC 3.2.1.15) activity, endopolygalacturonase protein detected immunologically and water-soluble uronide were measured in tomato fruit samples (cv. Rutgers) at different stages of ripening. Endopolygalacturonase activity and endopolygalacturonase protein were only detected in samples in which ripening had been initiated for 2 or more days. Enzyme activity and enzyme protein increased during ripening and were highly correlated. A high molecular weight form of the enzyme appeared 2 or 3 days after ripening was initiated. Lower molecular weight forms of endopolygalacturonase appeared later and eventually accounted for most of the enzyme protein. The content of water-soluble uronide did not increase until fruit had been ripening for 4 or more days. It is concluded that endopolygalacturonase is not involved in the initiation of ripening.

Two synthetic routes to the octahydroindeno[lV2-b]furanone derivative strigol (1 ), a germination stimulant of witchweed seeds, and its stereoisomers are described.

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A diene synthesis using 2,6-xyloquinone as dienophile and boron trifluoride as catalyst does not follow the normal orientation rules and leads to a facile synthesis of ring A-aromatic steroids. A tetracyclic adduct prepared by a similar reaction and containing the steroidal C19-methyl group is also reported.

Thermolyses in polar solvents, of Δ3-1,3,4-oxadiazolin-2-ones or 2-phenylimino-Δ3-1,3,4-oxadiazolines derived from α,β-epoxyketones, yields acetylenic carbonyl compounds. Good yields of acetylenic aldehydes and ketones are obtained for those cases in which the epoxide is ring fused. Extension to acyclic cases failed primarily due to predominance of a parallel decomposition pathway. The method complements the procedures developed by Eschenmoser and co-workers for the conversion of, α,β-epoxyketones into acetylenic carbonyl compounds.