Gas-phase pyrolytic reactions of esters of 2-pyridine and 8-quinoline sulfonic acid

The rates of gas-phase thermal elimination reaction of esters of 2-pyridine sulfonic acid and 8-quinoline sulfonic acid have been measured over at lea st 50 degrees for each compound. The relative rates of the first-order unim olecular decomposition at 500 K for the primary:secondary esters suggest th at C-O bond breaking is kinetically more significant than C-H bond breaking , leading to a transition state of carbocationic character. This is consist ent with the electron-donating effect provided by the methoxy substituent i n 2-p-methoxyphenylethyl of 2-pyridine and 8-quinoline sulfonate esters sta bilizing the carbocation center. (C) 2000 John Wiley & Sons, Inc.