1,1',3,3'-Tetramethyl-5-(4-methylamino-3-nitrobenzyl)-5,5'-methylenebisbarbituric acid

Abstract

The previously proposed structure (2) for the compound named in the title is confirmed by spectroscopic methods and by synthesis of related compounds. The barbituric acid undergoes a very facile thermal fragmentation in the mass spectrometer into 1,3-dimethyl-5-(4-ethylamino-3-nitrobenzy1)-barbituric acid (3) (which was also prepared by unambiguous synthesis) and 1,3-dimethyl-5-methylenebarbituric acid (4). The electron-impact, chemical-ionization, and negative-ion mass spectrometric behaviour of the barbituric acid (2) was examined.