Amidines. Part 13. Influence of substitution at imino nitrogen atom on pKavalues of N1N1-Dimethylacetamidines
- 1 January 1984
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 10,p. 1643-1646
- https://doi.org/10.1039/p29840001643
Abstract
20 N1N1-Dimethylacetamidines containing alkyl, aralkyl, or substituted phenyl groups have been synthesized, and their pKa values in 95.6% ethanol (azeotrope) measured. The pKa values obtained were correlated with Hammett σ constants. The appliciability of various σ values is discussed, and it is shown that for substituents at nitrogen σ° values should be used. It has also been shown that the pKa values of amidines correlate well with the pKa values of corresponding primary amines, and that this correlation can serve for the prediction of the pKa of amidine. Comparison of the correlations for N1N1-dimethylacetamidines with those for N1N1-dimethylformamidines indicate that sensitivity of the amidine group to substitution at the imino nitrogen atom depends to a considerable degree on substitution at a functional carbon atom.Keywords
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