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Aminopyrazoles. V . Structure assignment of 1 H ‐pyrazol‐3‐and 5‐amines by means of the 1 H NMR δ(4‐H)‐values of their exo‐N ‐toluenesulfonyl derivatives
Author(s) -
Ege Günter,
Franz Hermann
Publication year - 1984
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570210312
Subject(s) - chemistry , substituent , chemical shift , tosyl , pyrazole , medicinal chemistry , computational chemistry , stereochemistry
From the extent of the low field chemical shift of 4‐H caused by exo‐N ‐tosylation of 1‐substituted 1 H ‐pyrazolamines it is possible to distinguish between the 3‐ and 5‐amino‐isomers. The pyrazole substituent increment system of Tensmeyer and Ainsworth has been extended to 3‐ and 5‐amino, 3‐ and 5‐tosylamino, 1‐benzyl and 1‐tosyl substituents. By comparison of δ(4‐H) values, calculated with the aid of these increments, with measured δ(4‐H) values, a differentiation between 3‐ and 5‐tosylaminopyrazoles but not between 3‐ and 5‐aminopyrazoles can be made.