1.2.3.4.5.6- Hexasubstituted cyclohexane

The vast majority of discotic mesogens with cyclohexane cores and six substituent chains are based on ui- and s-IS. Pertinent to the discussion above concerning the relationship between the direction of projection of chains on 1,2,3,4,5,6-hexasubstituted cyclohexanes, the hexa(n-hexyl) ether of m-IS with one axial hexyloxy (6-O-m-IS) has been shown not to be liquid crystalline the corresponding s-IS hexaether with a more disk-like shape (6-O-s-IS) forms an enantiotropic columnar discotic phase... 

If the fluoro-compounds be excepted the results in Tables 4 and 5 can be generalised as follows. Barriers for 1,1-disubstituted cyclohexanes are not consistently different from those of the unsubstituted compound while those in 1,1,4,4-tetrasubstituted cyclohexanes are slightly larger than in cyclohexane itself. ) Barriers to ring inversion in 1,1,3,3-tetrasubstituted cyclohexanes are slightly lower than in cyclohexane while those of 1,1,3,3,5,5-hexasubstituted cyclohexanes are substantially lower. 

An unusual group of antibiotics, the aminoglycoside antibiotics, is based on oligosaccharide structures almost exclusively. Of particular therapeutic importance is streptomycin (an antituberculosis agent), isolated in 1944 from cultures of the mold Streptomyces griseus. The molecule consists of three subunits the furanose streptose, the glucose derivative 2-deoxy-2-methylamino-L-glucose (an example of the rare l form), and streptidine, which is actually a hexasubstituted cyclohexane. 

Under the conditions of Figure 12.12 acetophenone yields 1,3,5-triphenylbenzene. Lewis rather than Bronsted acids initiate the cyclodehydration of ketones to give aromatic compounds in an analogous fashion. Under influence of titanium tetrachloride and zinc chloride the steroid coprostanone, for example, leads to the formation of hexasubstituted benzene the 3x3 cyclohexane chairs that constitute the substituents of the resulting benzene ring are rigid... 

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