Ab initio method study on the isomerization of 3-amino-2-pyridone

Ab initio calculations with RHF/6-31G and MP2/6-31G have been used to study the isomerization of 3-amino-2-pyridone in gas-phase and in water. The res ults obtained show that 3-amino-2-pyridone is isomerized into 3-amino-2-hyd roxy pyridine via a four-center cyclic transition state in the gas-phase, a nd via a six-center cyclic transition state in water. The activation energi es of this reaction are 226.3336(RHF/6-31G) and 171.2269(MP2/6-31G) in gas- phase, and 81.6398(RHF/6-31G) and 59.8668(MP2/6-31G) kJ mol(-1) under the c ondition of a single water molecule as the catalyst, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.