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15 N, 13 C and 1 H NMR study of azo coupling products from diazonium salts and enaminones
Author(s) -
Macháček Vladimír,
Lyčka Antonín,
Šimůnek Petr,
Weidlich Tomáš
Publication year - 2000
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(200004)38:4<293::aid-mrc639>3.0.co;2-x
Subject(s) - tautomer , chemistry , azo coupling , salt (chemistry) , chemical shift , carbon 13 nmr , diazonium compounds , coupling constant , proton nmr , medicinal chemistry , computational chemistry , stereochemistry , organic chemistry , physics , particle physics
Reactions of diazonium salts with 4‐substituted phenylaminopent‐3‐en‐2‐ones produce the corresponding 4‐phenylimino‐3‐phenylhydrazonopentan‐2‐ones. On the other hand, the reaction of diazonium salt with 4‐amino(or 4‐methylamino)pent‐3‐en‐2‐one gives a mixture of two isomers approaching the tautomeric form of 4‐amino‐3‐phenylazopent‐3‐en‐2‐ones. The tautomeric form of the individual coupling products was determined by means of 13 C and 15 N NMR chemical shifts and J ( 15 N,H) coupling constants. With the help of TPPI‐NOESY spectra it was possible to follow the rate of mutual exchange of four protons of NH groups in both isomers of 4‐amino‐3‐(4‐methylphenylazo)pent‐3‐en‐2‐one. Copyright © 2000 John Wiley & Sons, Ltd.