22037-22-5Relevant academic research and scientific papers
AZA-ENAMINES-VII. UMPOLUNG OF THE AZOMETHINE REACTIVITY IN THE REACTION OF ALDEHYDE HYDRAZONES WITH SULFONYL ISOCYANATES SUBSTITUENT EFFECTS
Brehme, Rainer,Klemann, Anke
, p. 4113 - 4118 (2007/10/02)
Sulfonyl isocyanates attack the arylaldehyde N,N-dialkylhydrazones 1-3 at the nitrogen or carbon of the azomethine function leading to the formation of the hexahydro-1,3,5-triazine-2,4-diones 4-6 or arylglyoxylic acid sulfonamide-N,N-dialkylhydrazones 7-9 (scheme 1).Under equal experimental conditions the position of the electrophilic attack depends on the contribution of the dipolar structures I'I'' determined by the electron withdrawing or donating potential of the substituents R1 and NR2.The normal reactivity of the =C=N-function is described by eq.1, the umpolung by eq.2.These different reactions correspond to the 13C-chemical shifts of the azomethine carbon atoms.
