Results of the bromination and dehydrobromination of several angular methylated decalindiones are described. The key reaction, base-induced cyclization of the monobromo keto ester (3), and the dibromo ketone (4), leads to the formation of tricyclic systems (6) and (9) respectively.

Microorganisms are well-known producers of a wide variety of bioactive compounds that are utilized not only for their primary metabolism but also for other purposes such as defense, detoxification, or communication with other micro- and macro-organisms. Natural products containing a 'decalin ring' occur often in microorganisms. They exhibit diverse and remarkable biological activities, includin...

Electrocyclic ring opening of 4,6-fused cyclobutenamides 1 under thermal conditions leads to cis,trans-cyclooctadienones 2-E,E as transient intermediates, en route to 5,5-bicyclic products 3. Theoretical calculations predict that 4,5-fused cyclobutenamides should likewise undergo thermal ring opening, giving cis,trans-cycloheptadienones, but in this case conversion to 5,4-bicyclic products is t...

In the title compound, C31H30N2O, the cis-fused cyclo-hexene and cyclo-octane rings adopt boat and boat-chair conformations, respectively. The essentially planar five-membered N-heterocyclic ring [r.m.s. deviation = 0.017 (1) Å] is cis- and trans-fused, respectively, with the cyclo-hexene and cyclo-octane rings. In the crystal, mol-ecules are linked into inversion dimers through pairs of weak C...

Reactions between conjugated dienols and maleic anhydride provide either cis-fused or trans-fused bicyclic products as major products, depending upon how the reaction is carried out. Simply mixing the two reactants together generally leads to cis-fused lactone acids in thermal reactions which proceed viaintermolecular Diels-Alder reaction followed by intramolecular esterification. Pre-forming t...

GroEL encapsulates non-native protein in a folding cage underneath GroES (cis-cavity). Here we report the maximum size of the non-native protein to stay and fold in the cis-cavity. Using total soluble proteins of Escherichia coli in denatured state as binding substrates and protease resistance as the measure of polypeptide held in the cis-cavity, it was estimated that the cis-cavity can accommo...

The depletion-induced phase separation in a mixture of colloidal particles (PMMA-latex) and nonadsorbing polymers [poly(styrene)] in a solvent (mixture of tetralin, cis-decalin, and carbon tetrachloride) was investigated in real space with confocal scanning laser microscopy in the initial, intermediate, and final stage. It was found that the kinetics and the morphology of the phase separation s...

The title compound, digoxigenone, C(23)H(30)O(5)·H(2)O, was biotransformed from digoxigenin. In the crystal, inter-molecular O-H⋯O hydrogen bonds contribute to the formation of a three-dimensional supra-molecular structure. The title compound has three fused six-membered rings (A,B,C) and two non-fused five-membered rings (D,E). As in other structures, compound nucleus has a cis-trans-cis confo...

We investigate the dehydrogenation of decalin for the production of pure hydrogen for fuel cell applications. Supported Pt catalysts can achieve about 98% conversion with >99.9% selectivity for the dehydrogenation reaction. Cracking reactions occur only at high temperature. The partially dehydrogenated product, tetralin, was formed with a molar selectivity <6%, depending on the operating condit...