Mesityl oxide oxalic ester

By using mesityl oxide and oxalic ester the condensation product is mesityl-oxide-oxalic ester ... 

There is of course ample evidence that acid-base catalysis in solvents of low dielectric constant does not necessarily involve a concerted process. Such a process cannot operate when catalysis is effected by a single acid or base present in an aprotic solvent, and there are many examples of this, including typical prototropic reactions such as the halogenation of acetone, the racemization and inversion of optically active ketones, and the mutarotation of nitrocamphor. Moreover, in the isomerization of mesityl oxide oxalic ester in chlorobenzene, which depends kinetically on the interconversion of two isomeric enols, the velocity in a solution containing both an amine and an acid is no greater than the sum of the velocities for the two catalysts separately, in contrast to the behaviour found by Swain for the mutarotation reaction. 

In these classes directions of both left- and right-handed rotation of the plane of polarization must exist in the same crystal. An earlier claim that optical activity is exhibited by a crystal in class m (mesityl oxide oxalic methyl ester) has since been disproved, but it has been experimentally verified in both 4 (CdGa2S4) and 42m (AgGaSj). )... 

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