Gas-phase pyrolytic reactions of N-ethyl, N-isopropyl, and N-t-butyl substituted 2-aminopyrazine and 2-aminopyrimidine

The rates of gas-phase elimination of N-ethyl (1), N-isopropyl (2), N-t-but yl (3) substituted 2-aminopyrazine and N-ethyl (4), N-isopropyl (5), and N- t-butyl (6) substituted 2-aminopyrimidine have been measured. The compounds undergo unimolecular first-order pyrolytic reactions. The relative rates o f the primary:secondary: tertiary alkyl homologues at 600 K are 1 : 14.4: 3 8.0 for the pyrazines and 1 :20.8: 162.5 for the pyrimidines, respectively. The reactivities of these compounds have been compared with those of the a lkoxy analogues and with each other. Product analyses, together with the ki netic data. were used to outline a feasible pathway for the elimination rea ction of the compounds under study. (C) 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 403-407, 2000.