Metal and acid-free synthesis of acenaphthenone-2-ylidene ketones in PEG 400 and their radical nitration by TBN in water.

The synthesis of acenaphthenone-2-ylidene ketones has been developed using PEG 400 as a solvent under metal and acid-free conditions. Using TBN as a nitrating agent under atmospheric oxygen, nitration of acenaphthenone-2-ylidene ketones has been accomplished for the first time. Upon nitration, (E)-2-(2-oxo-2-phenylethylidene)acenaphthylen-1(2H)-one and alkyl (E)-2-(2-oxoacenaphthylen-1(2H)-ylidene)acetate give the diastereomer with the same geometry. The variety of substrates employed and low cost and non-toxicity of the chemicals used in this process demonstrate its important applicability. Another noteworthy aspect of the procedure is that, in contrast to previous procedures, it does not use HNO3 or metal nitrates during the transformation.