Structures of angrendiol, ferolin, and chimganidin
SummaryOn the basis of the results of a study of the products of chemical transformations and spectra, the structure of angrendiol has been established as 4,8-dihydroxygermacra-1(10), 5(6)-diene. It has been shown that ferolin and chimganidin are monoesters of angrendiol with parahydroxybenzoic and vanillic acids, respectively, at the secondary hydroxy group.
Cope rearrangement of some germacrane-type furan sesquiterpenes. Part I
Cope rearrangements of some germacrane-type furan sesquiterpenes have been examined and the absolute configuration of the rearrangement products has been confirmed. The results suggest that the stereochemistry of the rearrangement product is controlled by the conformation of the ten-membered ring compound.
Submicron polymer structures with X-ray lithography and hot embossing
This article describes the process chain for replication of submicron structures with varying aspect ratios (AR) up to 6 in polymethylmethacrylate (PMMA) by hot embossing to show the capability of the entire LIGA process to fabricate structures with these dimensions. Therefore a 4.7 μm thick layer of MicroChem 950k PMMA A11 resist was spin-coated on a 2.3 μm Ti/TiOx membrane. It was patterned with X-ray lithography at the electron storage ring ANKA (2.5 GeV and λc ≈ 0.4 nm) at a dose of 4 kJ/cm3 using a Si3N4 membrane mask with 2 μm thick gold-absorbers. The samples were developed in GG/BDG and resulted in AR of 6–14. Subsequent nickel plating at 52°C resulted in a 200 μm thick nickel tool of 100 mm diameter, which was used to replicate slit-nozzles and columns in PMMA. Closely packed submicron cavities with AR 6 in the nickel shim were filled to 60% during hot embossing.