DIAZABENZENES .2. SYNTHESIS, PHOTOLYSIS AND MASS-SPECTRA OF SOME TETRAALKYLPYRAZINES

2, 3, 5, 6- Tetramethyl-, tetraethyl- and tetraisopropyl-pyrazines were obtained by fusion of ammonium acetate with the appropriate acyloin or reduction of the α, ά-diketone dioxime with zinc dust and alkali. Photolysis of a cyclohexane solution of tetraisopropylpyrazine led inter alia to formation of bicyclohexyl. Photolysis of an aqueous solution of tetramethylpyrazine containing sodium boro- hydride caused complete reduction of the pyrazine ring to the hexahydro stage. The high-resolution mass spectra of these pyrazines are discussed and explained in the light of deuterium labelling and metastable defocusing information. © 1979, CSIRO. All rights reserved.