The initial reaction of primary amines with pyrylium cations to give the ring-opened intermediate is fast for strongly basic amines and is base-catalysed for weak amines. Ring-closure of the intermediate to give the pyridinium derivative is subject to steric and electronic hindrance and is acid-catalysed. Solvent effects and the structure of the ring-opened intermediates are discussed.
If you are not the author of this article and you wish to reproduce material from it in a third party non-RSC publication you must formally request permission using RightsLink. Go to our Instructions for using RightsLink page for details.
Authors contributing to RSC publications (journal articles, books or book chapters) do not need to formally request permission to reproduce material contained in this article provided that the correct acknowledgement is given with the reproduced material.
Reproduced material should be attributed as follows:
If the material has been adapted instead of reproduced from the original RSC publication "Reproduced from" can be substituted with "Adapted from".
In all cases the Ref. XX is the XXth reference in the list of references.
If you are the author of this article you do not need to formally request permission to reproduce figures, diagrams etc. contained in this article in third party publications or in a thesis or dissertation provided that the correct acknowledgement is given with the reproduced material.
Reproduced material should be attributed as follows:
If you are the author of this article you still need to obtain permission to reproduce the whole article in a third party publication with the exception of reproduction of the whole article in a thesis or dissertation.
Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.
Fetching data from CrossRef.