A Challenge to Revisit Deamination Mechanisms

In Sections 7.3-7.5, we discussed a selection of investigations on the deamination mechanisms of aliphatic amines by direct nitrosation in various solvents and by rearrangement processes of amine derivatives. These investigations are a very small fraction of all studies made in that area. It would take too many pages to summarize, and even more, to critically discuss the majority of all results. 

In 1983, Kirmse and Siegfried published a paper with the title 2-Norbornane-diazonium Ions Revisited . These authors considered it essential to reinvestigate the deamination of the endo- and exo-norbornylamine, not least within the context of the well-known discussion on nonclassical carbocations. We adopt the word revisit from this paper for this section and combine it with challenge , i. e., an expression indicating encouragement to reinvestigate deamination mechanisms in the future, because today (1995) we still have the impression that there are too many ambiguities in mechanistic interpretations of experimental results in deamination studies. 

Results obtained during the last ten years or so are certainly more reliable Bartlett s statement in 1965 of a need for better resolved reagents and for improved separations of isomers for work on nonclassical carbocations was definitely appropriate. Care was taken successfully, as shown by the investigation of the deamination of [l- H]butylamine by Brosch and Kirmse (1991) discussed in Section 7.3. 

All these interpretations fit the experimental results - but which is the most credible This question is, in our opinion, a typical case to be solved on the basis of Popper s book Logic of Scientific Discovery (1935, 1980) A hypothesis is postulated from observations. The hypothesis should then be tested by experiment, designed either to verify or to falsify the original hypothesis. A verification is never definitive and absolute, but a falsification is. If two or more hypotheses fit certain experimental results, a new experiment must be designed in such a way that it will verify one hypothesis, but falsify the other. By such a procedure, erroneous hypotheses can be 

To decide difficult cases one often uses as a stopgap the principle of Ockham s razor, i.e., one choses that interpretation of a mechanism that is the simplest. If the basis for this choice is clearly declared as a stopgap, it is acceptable — in spite of the danger that, later, other scientists will quote that interpretation without reservation. 

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