THE NATURE OF THE TRANSITION-STATE IN AMIDES PYROLYSIS - THE RATES OFPYROLYSIS OF N-BENZOYL AND N-ACETYLPROPANAMIDE, N-BENZOYL AND N-ACETYL-2-METHYLPROPANAMIDE, AND N-THIOACETYLPROPANAMIDE

The rates of gas-phase elimination reactions of N-benzoyl and N-acetyl -propanamide and N-benzoyl and N-acetyl-2-methylpropanamide are measur ed and discussed. They undergo unimolecular first-order elimination re actions. The reactivities of N-benzoylamides have been compared with e ach other and with those of N-acetylamides. The kinetic data together with the product analysis reveals that, the statistical factor of the availability of beta-hydrogen atoms for elimination as well as steric factor are obscured by polar factor in gas-phase elimination reactions of N-benzoylamides while the statistical factor rather than electroni c effect operates in each of N-acetylamides. (C) 1995 John Wiley & Son s, Inc.