Quantum Chemical Calculation of Fluorine-Containing Pyrimidines

摘要

Quantum chemical calculation of a molecules of 2-methylsulfanil-4-difluoromethoxypyrimidine,2-ethylsulfanil-4-difluoromethoxypyrimidine,2-isopropyl sulfanil-4-difluoromethoxypyrimidine,2-isobutylsulfanil-4-difluoromethoxypyrimidine, 2-methylsulfanil-4-difluoromemoxy-6-methylpyrimidine,2-ethylsulfanil-4-difluoro methoxy-6-methylpyrimidine,2-isobutylsulfanil-4-difluoromethoxy-6-methylpyrimidine is executed by methods MNDO and AB INITIO in base 6-311G** with optimization of geometry on all parameters for the first time. The Optimized geometrical and electronic structure of these compounds is received. Acid force of these compounds is theoretically appreciated (MNDO: 26≤pKa≤27, AB INITIO: 28≤pKa≤32). It is established, than 2-methylsulfanil-4-difluoromethoxypyrimidine,2-ethylsulfanil-4-difluoromethoxy pyrimidine,2-isopropylsulfanil-4-difluoromethoxypyrimidine,2-isobutylsulfanil-4-difluoromethoxypyrimidine,2-methylsulfanil-4-difluoromethoxy-6-methylpyrimidine,2-ethylsulfanil-4-difluoromethoxy-6-methylpyrimidine,2-isobutylsulfanil-4-difluoro methoxy-6-methylpyrimidine to relate to a class of weak H-acids (pKa＞14).