Nucleophilic Substitution Reactions of O-Methyl N,N-Diisopropylamino Phosphonochloridothioate with Anilines and Pyridines

作者：Barai Hasi Rani; Lee Hai Whang^*

来源：BULLETIN OF THE KOREAN CHEMICAL SOCIETY, 2014, 35(4): 1016-1022.

DOI：10.5012/bkcs.2014.35.4.1016

• Thiophosphoryl transfer reaction
• Anilinolysis
• Pyridinolysis
• O-Methyl N,N-diisopropylamino phosphonochloridothioate
• Biphasic concave upward free energy relationship

The kinetic studies on the reactions of O-methyl N,N-diisopropylamino phosphonochloridothioate with X-anilines and X-pyridines have been :carried out in acetonitrile. The free energy relationship with X in the anilines exhibits biphasic concave upward with a break region between X = (H and 4-F), giving unusual negative beta(X) and positive rho(X) values with weakly basic anilines. The unusual phenomenon is rationalized by isokinetic relationship. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed based on the selectivity parameter and variation trend of the deuterium kinetic isotope effects with X. The free energy relationship with X in the pyridines exhibits biphasic concave upwards with a break point at X = 3-MeO. A concerted mechanism is proposed based on relatively small beta(X) value, and frontside and backside nucleophilic attack are proposed with strongly and weakly basic pyridines, respectively.

• 出版日期2014-4-20