Triterpenes from the leaves ofBetula ermanii
SummaryFrom the unsaponifiable fraction of an ethereal extract of the leaves ofBetula ermanii a new triterpene of the dammarane series — 20,24-epoxydammarane-3β,6α,25-trol (II) — and its 6-O-acetyl derivative (I) have been isolated.
13C NMR Study of ginseng sapogenins and their related dammarane type triterpenes
Abstract In connection with structure studies on dammarane type triterpenes and their glycosides, assignments of 13 C NMR signals of fifteen 20-hydroxy-dammarane derivatives including Ginseng sapogenins have been achieved by the aid of shift reagents and deuterated compounds. It has been found that the differences of the 17 C, 21 C and 22 C chemical shifts between pairs of C-20 epimers are remarkable especially in the case of 12β-hydroxy derivatives, being significant for the study of the C-20 stereochemistry.
Hill country sheep production. I. The influence of age, flock, and year on some components of reproduction rate in Romney and Border Leicester × Romney ewes.
Data from 7,091 straightbred Romney and Border Leicester × Romney ewes grazed at the Whatawhata Hill Country Research Station over the period 1959 to 1967 have been used to obtain estimates of flock and age-of-ewe effects on reproduction rate and its components and of year-to-year variation. The ewes were from six groups: a Romney control (RCR) flock, a Romney flock in which ewes were mated either to Romney (RER) or to Border Leicester rams (REB), and flocks of first-cross (F1), second-cross (F2), and third-cross (F3) Border Leicester × Romney ewes mated to first-cross Border Leicester × Romney rams. The ewes' ages at lambing varied from 2 to 5 years and no selection was practised. The ratio of number of lambs weaned per ewe present at lambing increased from the RCR (0.84) to the F1 (1.07), then declined with interbreeding to the F2 (0.92) and further to the F3 (0.87) ewes. Similar changes were evident for the percentage of ewes lambing, of multiple births, and of lambs surviving to weaning. Over...