Organic reactions in a solid matrix—V: Silica-gel supported chromic acid reagents

Pyridinium chromate-on-silica gel, and chromic acid-on-silica gel are described and evaluated as convenient off-the-shelf reagents for efficient oxidation of a variety of secondary and primary alcohols. Pyridinium chromate-on-silica gel can be safely used for the oxidation of alcohols containing acid-labile functions.     

A novel method for functionalization of C-4 methyl in triterpenoids. A synthesis of cycloeucalanone

Functionalization of 4-methyl group in cycloartane-type triterpenoids has been accomplished utilizing, in the key step, photolytic decomposition of an hypoiodite derived from a 3β-hydroxymethyl-4,4-dimethyl precursor. The synthesis of cycloeucalanone from cyclolaudanone is reported.     

Azulenes and related substances—XI A new azulene synthesis—azulene, 1-methyl-2-methyl- and 1, 3-dimethylazulene

The polyphosphoric acid induced intramolecular acylation of lactones has been applied to the synthesis of the bicyclo [0,3,5] decane system, and the preparation of azulene, 1-methyl-, 2-methyl- and 1,3-dimethylazulene is reported.     

Studies in sesquiterpenes—LI : β-Himachalene epoxide—stereochemistry and solvolysis

Stereochemistry of β-himachalene oxide has been established by its correlation with himachalol. Products of solvolysis of this oxide are dependent on conditions and reagents used. Homoallylic participation becomes the dominant mode with perchloric acid in aqueous dioxane.     

A rapid method for direct quantitative analysis on chromatographic layers

Summary A rapid method is described for direct quantitative determination on the chromatographic layer. The method is based on the measurement of the length of the chromatographic band in the direction of flow.     

Fission track annealing and age determination of hornblende

Hornblende which occurs in igneous and metamorphic rocks is well suited for age determination by the fission track method. The tracks which are readily etched in hydrofluoric acid are annealed in 1 hr at 530° C. Extrapolation of the experimentally determined temperatures suggest that a temperature of 200° C for one m.y. will erase all the tracks present before the heating. Fission track ages of hornblende agree with the main orogenic metamorphic cycles.     

Under what kind of parametric fluctuations is spatiotemporal regularity the most robust?

It was observed that the spatiotemporal chaos in lattices of coupled chaotic maps was suppressed to a spatiotemporal fixed point when some fractions of the regular coupling connections were replaced by random links. Here we investigate the effects of different kinds of parametric fluctuations on the robustness of this spatiotemporal fixed point regime. In particular we study the spatiotemporal dynamics of the network with noisy interaction parameters, namely fluctuating fraction of random links and fluctuating coupling strengths. We consider three types of fluctuations: (i) noisy in time, but homogeneous in space; (ii) noisy in space, but fixed in time; (iii) noisy in both space and time. We find that the effect of different kinds of parametric noise on the dynamics is quite distinct: quenched spatial fluctuations are the most detrimental to spatiotemporal regularity; spatiotemporal fluctuations yield phenomena similar to that observed when parameters are held constant at the mean value, and interestingly, spatiotemporal regularity is most robust under spatially uniform temporal fluctuations, which in fact yields a larger fixed point range than that obtained under constant mean-value parameters.