2-Trifluoromethylperimidines with electron-withdrawing groups at the 6(7)-position: a case of extremely hindered annular prototropy

摘要

In solutions of 6(7)-formyl-, 6(7)-acetyl- and 6(7)-p-toluenesulfonyl-2-trifluoromethylperimidines in non-polar solvents, both of the NH tautomers were detected using H-1 NMR spectroscopy even on heating up to 130 degreesC. [References: 12]