Planar molecules enzyme induction

Since there is a molecular size and shape requirement for tumor induction by PAHs, either modifying (a) the size of the incumbrance area of planar molecule to < 100 or >135 A2, (b) the shape to contain more than four fused, linearly oriented rings, or (c) the structure to be symmetric will make the chemical less favorable for absorption, enzyme activation, and DNA interaction. 

PCN exposure to rats causes enzyme induction in the liver, kidney and lung [250-252]. Mixed-function oxygenases (MFO) are involved in the hydroxyla-tion of xenobiotica. The induction potency of a compound depends on the chlorination degree, substitution pattern and planarity of the molecule. The compounds 3-methylcholanthrene and phenobarbital induce two different... 

Desymmetrization of an achiral, symmetrical molecule through a catalytic process is a potentially powerful but relatively unexplored concept for asymmetric synthesis. Whereas the ability of enzymes to differentiate enantiotopic functional groups is well-known [27], little has been explored on a similar ability of non-enzymatic catalysts, particularly for C-C bond-forming processes. The asymmetric desymmetrization through the catalytic glyoxylate-ene reaction of prochiral ene substrates with planar symmetry provides an efficient access to remote [28] and internal [29] asymmetric induction (Scheme 8C.10) [30]. The (2/ ,5S)-s> i-product is obtained with >99% ee and >99% diastereoselectivity. The diene thus obtained can be transformed to a more functionalized compound in a regioselective and diastereoselective manner. 

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