Aza-enamines-VII: Umpolung of the azomethine reactivity in the reaction of aldehyde hydrazones with sulfonyl isocyanates substituent effects

摘要: Abstract Sulfonyl isocyanates attack the arylaldehyde N,N-dialkylhydrazones 1 - 3 at nitrogen or carbon of azomethine function leading to formation hexahydro-1, 3,5-triazine-2,4-diones 4 6 arylglyoxylic acid sulfonamide-N, N-dialkylhydrazones 7 9 (scheame 1). Under equal experimental conditions position electrophilic depends on contribution dipolar structures IXXX XXX determined by electron withdrawing donating potential substituents R1 and NR2. The normal reactivity CN-function is described eq.1, umpolung eq.2. These different reactions correspond 13C-chemical shifts atoms.