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Kinetics of the reaction of 2-chloro-3-nitro- and 2-chloro-5-nitropyridines with aryloxide ions in methanol

✍ Scribed by Ali A. El-Bardan

Publisher: John Wiley and Sons
Year: 1999
Tongue: English
Weight: 71 KB
Volume: 12
Category: Article
ISSN: 0894-3230
DOI: 10.1002/(sici)1099-1395(199904)12:4<347::aid-poc134>3.0.co;2-g

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✦ Synopsis

The kinetics of the reaction of 2-chloro-3-nitropyridine (ortho-like) and 2-chloro-5-nitropyridine (para-like) with a series of aryloxide ions were studied in methanol at different temperatures. Plots of DH ≠ versus DS ≠ for both reactions gave good straight lines with isokinetic temperatures of 168 and 195 °C. Good linear relationships were obtained from the plots of log k 2 against s°values with relatively large negative r values indicating the formation of Meisenheimer s-complex intermediates. Plots of log k 2 against pK a values gave good straight lines indicating that the reactions show an appreciable degree of bond formation in the transition state. An additionelimination mechanism is suggested.

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