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Anilinolysis of O ‐butyl phenyl phosphonochloridothioate in acetonitrile: Synthesis, characterization, kinetic study, and reaction mechanism
Author(s) -
Barai Hasi Rani,
Kim Jihoon,
Joo Sang Woo
Publication year - 2017
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3679
Subject(s) - chemistry , kinetic isotope effect , sn2 reaction , acetonitrile , deuterium , nucleophilic substitution , nucleophile , nuclear magnetic resonance spectroscopy , kinetic energy , selectivity , reaction mechanism , spectroscopy , computational chemistry , medicinal chemistry , stereochemistry , organic chemistry , catalysis , physics , quantum mechanics
This paper describes a simple optimized method for the synthesis of O ‐butyl phenyl phosphonochloridothioate ( 4 ) under mild conditions. The target compounds were characterized by 1 H‐nuclear magnetic resonance (NMR), 13 C‐NMR, and 31 P‐NMR spectroscopy, as well as mass spectroscopy. The apparent structure of 4 was confirmed by optimization using the B3LYP/6‐311 + G(d,p) level in the Gaussian 09 program in acetonitrile. The nucleophilic substitution reactions of 4 with X‐anilines (XC 6 H 4 NH 2 ) and deuterated X‐anilines (XC 6 H 4 ND 2 ) were investigated kinetically in acetonitrile at 55.0°C. The free energy relationship with X in the anilines looked biphasic concave upwards with a break region between X = H and X = 3‐MeO, giving large negative ρ X and small positive β X values. The deuterium kinetic isotope effects were secondary inverse ( k H / k D < 1: 0.789‐0.995) and the magnitudes, ( k H / k D ), increased when the nucleophiles were changed from weakly basic to strongly basic anilines. A concerted S N 2 mechanism is proposed on the basis of the selectivity parameters and the variation trend of the deuterium kinetic isotope effects with X.