On the unusual hydrolysis reaction of 8-acetamido-2,4,4,8-tetramethyl-3-azanium-bicyclo[3.3.1]non-2-ene perchlorate

The recently synthesized iminium salt 8-acetamido-2,4,4,8-tetramethyl-3-azanium-bicyclo[3.3.1]non-2-ene perchlorate (ATABNEP) shows unusual reluctance to undergo hydrolysis. It was established that ATABNEP is not attacked by water in acid or neutral media but readily reacts in alkaline solutions yielding the corresponding imine by direct abstraction of the iminium proton. The imine crystallizes as a monohydrate. Crystals belong to the monoclinic space group P21 with a = 6.915(2) A, b = 8.459(4) A, c = 13.287(6) A, β = 92.53(3)°. Crystal structure of this compound was determined by X-ray diffraction using direct methods and refined to an R factor of 5.6%. As expected, the organic molecule structure is practically the same as that of ATABNEP. The imine molecules are arranged in sheets parallel to the ab plane linked, within a sheet, through a net of hydrogen bonds via the water protons and the hydrogen atom of the acetamido group. Keywords: iminium salt, hydrolysis, X-ray diffraction, molecular structure.