Tetracyclic diterpenoids with a new carbon skeleton forming products of the cyclization of labdane diterpenoids
From the product of the cyclization of a mixture of isomeric ent-copalols (i) [i] with a mixture of formic and concentrated acids, we have isolated an oxygen-containing fraction (yield 47%) consisting of a mixture of five alcohols and their formates. Three of the alcohols proved to be known: isoagath-12-en-15-ols epimeric at Cz4 [2] and 14~-hibanol [3]. For the other two alcohols, with the composition C2oH3~O, structures (2) and (3) were shown, these being based on a new carbon skeleton [4].
Chiroptical studies. Part LXXXIX. An empirical analysis of the circular dichroism of hexahydroindanones, bicyclo[4.2.0]octan-7-ones, and their polycyclic analogues
An empirical analysis of c.d. data for five-membered ring ketones of the hexahydroindanone type, including androstan-15-ones, -16-ones, and -17-ones and similar compounds, has established the main features of the relationships between Cotton effects and structural and conformational types in this series. The analysis has been extended to a few compounds of steroid-like structure which include a cyclobutanone ring (bicyclo[4.2.0]octan-7-ones). Five stereochemical types of hexahydroindanone are recognised, three for hexahydroindan-1-ones and two for hexahydroindan-2-ones.In the first stage of the analysis, estimates of c.d. contributions (δΔIµ) are obtained from experimental data for the following units: (a) the bicyclic systems, (b) angular methyl groups, and (c)‘third rings’. Estimates of the contribution of the ‘second’(cyclohexane) ring to the total value of ΔIµ for each of the bicyclic systems are then obtained by regarding the effects of individual bonds of the ‘second’ ring as equivalent to those of C–Me bonds at ‘α’ or ‘β’ positions of the cyclopentanone ring. The δΔIµ values obtained in this way for ‘second’ rings are used to derive δΔIµ values for the chiral cyclopentanone rings themselves. The values confirm earlier suggestions that the sign and magnitude of the Cotton effect is controlled largely by the chirality of the cyclopentanone ring itself, although other major contributions may come from any ‘α’-quasi-axial substituents present at the ring junction. Effects of alkyl substituents elsewhere on the cyclopentanone ring are discussed briefly.
Use of a specific antiserum for renin detection in human kidney.
The use of anti-human renin antibodies made possible the intrarenal localization of renin in human kidney by immunofluorescence. In normal kidney, only some juxtaglomerular apparatus (JGA) were fluorescent. In these JGA, granular or diffuse fluorescence was only seen in afferent arterioles and was not present in all cells. In the ischemic areas of partially infarcted kidney, fluorescence was seen in all JGA and in interlobular arteries. In these arteries the most eccentric cells were often the most positive. In the nonischemic areas of the same kidneys, fluorescence was not seen in JGA, but was observed in proximal tubular cells, suggesting the reabsorption of filtered renin at this site.