THE REDUCTIVE DIMERIZATION OF N-BENZYLIDENE ANILINE

Abstract

The formation of alkali metal adducts of N-benzylidene aniline in several inert solvents is studied by protonolysis of the adducts and analysis of the reaction products, the diastereomeric N,N′,1,2-tetraphenylethylenediamines. With sodium and potassium metal in polar solvents, the product is predominantly the dd,ll diamine. With lithium metal or with solvents of low polarity, the product contains approximately equal quantities of the two diastereomers.It is demonstrated that the initially formed diastereomeric mixture generally contains appreciable amounts of the meso isomer. In polar solvents with sodium, isomerization to the stable dd,ll diastereomer occurs. However, with lithium or with sodium in nonpolar solvents, the isomerization does not occur. The reasons for the preponderance of the dd,ll-disodio compound in the equilibrating systems are discussed.